GB2196777A

GB2196777A - Automatic reverse mechanism for tape recorder

Info

Publication number: GB2196777A
Application number: GB08623660A
Authority: GB
Inventors: Shinsaku Tanaka; Kunio Kido
Original assignee: Tanashin Denki Co Ltd
Current assignee: Tanashin Denki Co Ltd
Priority date: 1986-10-02
Filing date: 1986-10-02
Publication date: 1988-05-05
Anticipated expiration: 2006-10-02
Also published as: HK48591A; SG34991G; GB2196777B; GB8623660D0

Abstract

Responsive to the stop of left-hand reel shaft 1b by full take-up of a magnetic tape thereon, a contact portion 33b of a cam follower 31b is separated from a cam surface 11b and a cam 12b is brought into contact with the contact portion 33b. A turnable lever 7b is hence caused to turn counterclockwise so that a gear 9b is separated from a gear 26b to interrupt transmission of the rotary force of a capstan 3b to the gear 26b. At the same time, a hook member 24 is caused to turn clockwise so as to allow a changeover bar 17 to return rightwards. As a consequence, a right-hand pinch roller 4a is pressed against a capstan 3a while the left-hand pinch, roller 4b is separated from the capstan 3b. A right-hand turnable lever 7a is pulled counterclockwise by a spring 27a, whereby a gear 9a is brought into meshing engagement with a gear 26 to drive the magnetic tape rightwards. <IMAGE>

Description

SPECIFICATION Automatic reverse mechanism for tape recorder BACKGROUND OF THE INVENTION 1) Field of the Invention: This invention relates to an automatic reverse mechanism for a tape recorder, which can automatically play the B side of a magnetic tape in the reverse direction without need to reverse the sides of the magnetic tape after the A side of the magnetic tape has been played.

2) Description of the Prior Art: As automatic reverse devices for tape recorders, there have heretofore been known those detecting electrically each end of a tape to energize a solenoid so that pinch rollers, which are provided on both sides of a magnetic head respectively, are operated alternately; those detecting mechanically the tension of a tape at each end thereof and operating pinch rollers alternately by the rotary forces of their corresponding flywheels or the like; etc.

Although a variety of automatic reverse devices has been known as mentioned above, the running direction of a tape at the beginning of each operation is the same as its running direction at the time of completion of the previous operation in each of such conventional devices.

Automatic reverse devices, in each of which each end of a tape is electrically detected to cause the tape to run in the reverse direction, are equipped with solenoids, thereby making their structures complex. Use of solenoids is also disadvantageous in reducing the dimensions of tape recorders.

Turning next to automatic reverse devices making use of the rotary force of a flywheel to reverse the running direction of a tape, they generally have such a structure that a pin is provided upright from a portion of the flywheel and a pinch roller changeover mechanism is kicked by the pin. This structure is however accompanied by such drawbacks that the balance of the flywheel may be impaired and since the tension of the tape becomes higher temporarily at the beginning of each operation, this increased tension may be detected to cause a false operation.

When the contents of information recorded on both A and B sides of a tape are continuous for example, it is always desired to start the playback of the information from the A side. In each of conventional automatic reverse devices, the running direction of a tape at the beginning of an operation is the same as that at the time of completion of the previous operation. The conventional automatic reverse devices hence required a cumbersome operation to return to the A side for the first time if the previous operation has been stopped in the course of the playback of the B side for example.

On the other hand, various types of automatic stop devices have been developed to stop tape recorders at one ends of magnetic tapes. There is however no automatic reverse mechanism which can also be used as an automatic stop device. If an automatic stop device is provided in addition to an automatic reverse mechanism, the overall structure of the tape recorder becomes unavoidably complex and renders difficult the size reduction of the tape recorder.

In a tape recorder equipped with a conventional automatic reverse mechanism, the magnetic tape, reel shafts and the like are not visible from the outside especially when the tape recorder is used in a form built in a vehicle. Such a tape recorder is hence accompanied by an inconvenience that the user cannot find out in which direction the tape is running.

Furthermore, a tape recorder equipped with a conventional automatic reverse mechanism does not permit free change-over from the playback mode to the fast feeding mode, from the fast feeding mode to the playback mode in the same feeding direction, or from the fast feeding mode to the playback mode in the opposite feeding direction.

SUMMARY OF THE INVENTION With the foregoing in view, the present invention has as the first object thereof the provision of an automatic reverse mechanism for a tape recorder, which can automatically reverse the running direction of a tape without need for accessory parts such as solenoids and hence facilitates the size reduction of the tape recorder, is free from adverse effects to the balance of flywheels and false operations, and makes the running direction of the tape always the same at the beginning of operations such as playback, recording and the like.

The second object of this invention is to achieve further size reduction and structural simplification of the automatic reverse mechanism which can achieve the first object of this invention.

The third object of this invention is to provide an automatic reverse mechanism for a tape recorder, which can automatically reverse the tape without need for accessories such as solenoids and hence facilitates the size reduction of the tape recorder, is free from adverse effects to the balance of flywheels and false operations, and can also be used as an automatic stop device.

The fourth object of this invention is to provide an automatic reverse mechanism for a tape recorder, which does not require accessories such as solenoids and hence facilitates the size reduction of the tape recorder, is free from adverse effects to the balance of fywheels and false operations, and permits free change-over from the playback mode to the fast feeding mode, from the fast feeding mode to the playback mode in the same feeding direction, or from the fast feeding mode to the playback mode in the opposite feeding direction.

The fifth object of this invention is to provide an automatic reverse mechanism for a tape recorder, which does not require accessories such as solenoids and hence facilitates the size reduction of the tape recorder, is free from adverse effects to the balance of flywheels and false operations, and allows to find out the running direction of the tape at a look.

In an automatic reverse mechanism according to the first embodiment of this invention for a tape recorder, rotation transmitting members and cam followers are respectively provided symmetrically with respect to a magnetic head. The rotation transmitting members are provided with eccentric cam surfaces and cams respectively. Pushing and urging portions are provided respectively on reel shafts. The rotations of the capstans are transmitted to their corresponding reel shafts by way of their corresponding rotation transmitting members and friction mechanisms.While the reel shafts are being rotated, the pushing and urging portions urge their corresponding cam followers so as to maintain contact portions, which are provided on parts of the cam followers respectively, in sliding contact with the corresponding cam surfaces but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, the cams are brought into contact with the contact portions so as to displace the rotation transmitting members to non-engagement positions where the rotation transmitting members are maintained out of engagement with their corresponding shafts.A pinch roller changeover member adapted to bring one of the pinch rollers into contact with its corresponding cap stan and to separate the other pinch rollers from its corresponding capstan is urged normally in one direction. When one of the rotation transmitting member is brought to a nonengagement position relative to its corresponding shaft, the pinch roller changeover member is caused to move in a direction opposite to its urged direction in response to the movement of the rotation transmitting member, whereby the pinch roller changeover member is locked by the hook member. This locking is released in response to the dis placement of the other rotation transmitting member to a non-engagement position relative to its corresponding reel shaft, so that the pinch roller changeover member is allowed to return and the running direction of the tape is changed.Furthermore, the hook member is released by an interlocking member which operates in association with a stopping operation or a playback or recording starting operation of the tape recorder and serves to determine the starting side of the cassette, whereby the running direction of the tape is always the same when the next operation is started.

Namely, when the separation of the contact portion of each cam follower from its corresponding cam surface continues, the cam is brought into contact with the contact portion and the rotation transmitting member is hence displaced to actuate the pinch roller changeover member. When the tape recorder is stopped or a playback or recording operation is started, the interlocking member for determining the starting side of the cassette is actuated so as to make the running direction of the tape always the same at the next playback or recording operation.

In the above-described construction, the pinch roller changeover member is not actuated while either one of the reel shafts is rotating. When either one of the reel shafts has stopped, the changeover member is moved in the opposite direction to alternately actuate the left-hand and right-hand pinch rollers. Accordingly, it does not require accessory parts such as solenoids and facilitates the size reduction.

The automatic reverse mechanism is free from such dangers that the balance of rotation of the flywheels may be deleteriously affected and false operations may take place at start.

Since the running direction of the tape is always the same at the beginning of a playback or recording operation, it is unnecessary to perform the cumbersome operation to reverse the running direction of the tape at the beginning of each playback operation, for example, even if the contents of information on the A and B sides of the tape are continuous.

According to the second embodiment of this invention, there is provided an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams-provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members to non-engagement positions where the rotation transmitting members are maintained out of engagement with their corresponding reel shafts;; a pinch roller changeover member capable of moving, in response to each displacement of either one of the rotation transmitting members to its non-engagement position relative to its corresponding reel shaft in a direction toward the side of the other rotation tr#ansmitting member, whereby one of the pinch rollers, which is associated with the other rotation transmitting member, is brought into contact with its corresponding capstan and the other pinch roller is separated from its corresponding capstan; a locked member capable of dispiacing-in association with each displacement of the magnetic head from its eject position to its playback or recording position;; .* a lock member for locking the locked member at a predetermined position so as to maintain the magnetic head at the playback or recording position thereof or releasing the locked member from the predetermined position so as to allow the magnetic head to return to the eject position thereof; and a selector member mounted on the pinch roller changeover member in such a way that the selector member can selectively assume either one of two positions, said selector member being adapted to displace the lock member and to release the lock member from the locked member only when the pinch roller changeover member moves toward either one of both sides relative to the magnetic head while the selector member assumes selectively one of the two positions thereof.

The automatic reverse mechanism of the second embodiment of this invention can bring such effects that in addition to those brought about the first embodiment, the automatic reverse mechanism can also be used as an automatic stop device depending on the position of the selector member of the automatic reverse mechanism.

According to the third embodiment of this invention, there is provided an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one- of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members from their respective rotation transmitting positions where the rotation transmitting members transmit the rotary forces of the capstans to their corresponding reel shafts;; a pinch roller changeover member for bringing, in response to each displacement of either one of the rotation transmitting position thereof, one of the pinch rollers, which is associated with said one of the rotation transmitting members, into contact with its corresponding capstan and separating the other pinch roller from its corresponding capstan and a tape running direction indicator connected to the pinch roller changeover member and being capable of assuming either one of predetermined two positions in accordance with the position of the pinch roller changeover member so as to indicate the running direction of the tape.

In addition to the advantages of the first embodiment of this invention, the automatic reverse mechanism of the third embodiment can brought about a still further advantage that the running direction of the tape can be readily observed from the indicator for the running direction of the tape. This additional advantage is extremely convenient particularly when the magnetic tape, reel shafts and the like are no visible from the outside, for example, when used in a form built in a vehicle.

According to the fourth embodiment of this invention, there is provided an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members from their respective rotation transmitting positions where the rotation transmitting members transmit the rotary forces of the capstans to their corresponding reel shafts; a pinch roller changeover member for bringing, in response to each displacement of either one of the rotation transmitting members from the rotation transmitting position thereof, one of the pinch rollers, which is associated with said one of the rotation transmitting members, into contact with its corresponding capstan and separating the other pinch roller from its corresponding capstan; and a head mounting member supporting the magnetic head thereon, said head mounting member being provided displaceably between a play position where the magnetic head is maintained in contact with the magnetic tape and a position other than the play position, where the magnetic head is separated from the magnetic tape, and being capable of separating the pinch rollers from their corresponding capstans on both sides of the magnetic head when the head mounting member moves from the play position toward the latter posi tion.; a tape running direction changeover member adapted to manually advance or retreat the pinch roller changeover member so as to change the running direction of the magnetic tape;; a fast-forward feeding member connected to the heat mounting member and normally biasing the head mounting member from the position other than the play position toward the play position, and when pushed manually, being capable of retreating the head mounting member toward the position other than the play position whereby the tape recorder is rendered ready to perform a fast-forward mode; a hook member adapted to hold the fastforward feeding member at a pressed position to maintain the tape recorder in the fast-forward mode when the fast-forward feeding member has been pressed manually to the pressed position, and to release the fast-forward feeding member from the pressed position when the fast-forward feeding member is pressed again; and an interlocking member for causing the hook member to release the fast-forward feeding member in response to each actuation of the tape running direction changeover member.

The automatic reverse mechanism of the fourth embodiment of this invention can bring about such advantages that in addition to the advantages of the second embodiment of this invention, an extremely wide variety of func tions are materialized because it permits free change-over from the playback mode to the fast feeding mode, from the fast feeding mode to the playback mode in the same feeding direction, or from the fast feeding mode to the playback mode in the opposite feeding direction.

According to the fifth embodiment of this invention, there is provided an automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at positions other than the centers of the reel shafts; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; an eccentric cam surface and cam provided about a rotary shaft of one of the rotation transmitting members;; a cam follower having a contact portion at one part thereof and being urged against the pushing and urging portion on the side of the reel shaft, which is rotating in the tape-winding direction, so as to maintain the contact portion thereof in sliding contact with the cam surface and hence to maintain the contact portion out of contact with the cam, but when the reel shaft is stopped and the contact portion assumes a position apart from the cam surface due to elimination of the urging force of the pushing and urging portion, being brought into contact at the contact portion thereof with the cam so as to displace the rotation transmitting member to a non-engagement position where the rotation transmitting member is maintained out of engagement with the stopped reel shaft;; a pinch roller changeover member provided reciprocally but normally biased in one direction, and when the rotation transmitting member equipped with the eccentric cam surface is displaced to its non-engagement position relative to its corresponding reel shaft, said pinch roller changeover member moving in a direction opposite to said biased one direction in response to the displacement of the rotation transmitting member equipped with the eccentric cam surface so as to move the other rotation transmitting member to the engagement position thereof relative to its corresponding reel shaft whereby one of the pinch rollers, which is associated with the other rotation transmitting member, is brought into contact with its corresponding capstan and the rotation transmitting member equipped with the eccentric cam surface is separated from its corresponding capstan; and a hook member for locking the pinch roller changeover member at a position when the pinch roller changeover member has been displaced to the locked position in the direction opposite to said biased one direction upon receipt of a moving force of the rotation transmitting member equipped with the eccentric cam surface, and when the pinch roller changeover member has received a moving force of the rotation transmitting member equipped with the eccentric cam surface, releasing the pinch roller changeover member from the locked position.

The automatic reverse mechanism of the fifth embodiment of this invention can bring about substantially the same advantages as the above-described advantages of the first embodiment of this invention. Since it requires only one cam follower, the structure can be reduced further in size and also simplified further. It has a further advantage that the production cost can also be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings, in which: Figure 1 to Figure 4 schematically illustrate the structure of an automatic reverse mechanism according to the first embodiment of this invention; Figure 5 is a cross-sectional view taken along line V-V in Fig. 4; Figure 6 to Figure 10 schematically show the structure of an automatic reverse mechanism according to the second embodiment of this invention; Figure 11 to Figure 12 schematically show the structure of an automatic reverse mechanism according to the third embodiment of this invention;; Figure 13 to Figure 16 schematically depict the structure of an automatic reverse mechanism according to the fourth embodiment of this invention; and Figure 17 is a cross-sectional view taken along line XVII-XVII in Fig. 14; Figure 18 to Figure 21 schematically illustrate the structure of an automatic reverse mechanism according to the fifth embodiment of this invention.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS Fig. 1 to Fig. 5 show the first embodiment of this invention. A right-hand reel shaft 1a is rotated in Fig. 1 while a left-hand reel shaft 1b is driven in Fig. 4. Fig. 2 and Fig. 3 illustrate the automatic reverse mechanism in the course of its change from the state shown in Fig. 1 to its state depicted in Fig. 4.

Referring first of all to Fig. 1, capstans 3a,3b, pinch rollers 4a,4b and the above-mentioned reel shafts 1a,1b are respectively disposed in a symmetrical arrangement. Small diameter gears 5a,5b and flywheels 6a,6b are respectively secured on the capstans 3a,3b.

Further, rotation transmitting members, namely, turnable levers 7a,7b are also provided on their corresponding capstans 3a,3b in such a way that the turnable levers 7a,7b are allowed to turn about their corresponding capstans 3a,3b. Rotation transmitting units composed in combination of large diameter gears 8a,8b and small diameter gears 9a,9b respectively are supported on one ends of the turnable levers 7a,7b via shafts 10a,10b. Eccentric cam surfaces 1 1a,1 1b are formed respectively about the shafts 10a,10b. In addition, cams 12a,12b also project from and in continuation with the shafts 10a,10b at positions where the eccentric cam surfaces 1 1a,1 1b have the maximum radii. On the other hand, the other ends of the turnable levers 7a,7b terminate in bent end portions 13a,13b.

The pinch rollers 4a,4b are supported on brackets 15a,15b, which are pivotal about pivots 14a,14b respectively, so that the pinch rollers 4a,4b can be releasably brought into contact with their corresponding capstans 3a,3b. Bent edge portions 16a,16b are also provided on the brackets 15a,15b.

Designated at numeral 17 is a pinch roller changeover member, namely, a changeover bar which is slidable horizontally as viewed in Fig. 1. This changeover bar 17 is provided with lugs 18a,19 in such a way that the bent end portion 13a of the right-hand lever 7a is interposed between the lugs 18a,19. Furthermore, a lug 18b is provided on the changeover bar 17 at a position on the left of the bent end portion 13b of the left-hand turnable lever 7b. The changeover bar 17 also defines openings 20a,20b which receive the bent edge portions 16a,16b of the brackets 15a,15b respectively. Tilted edges 21a,21b are formed by the openings 20a,20b.When the changeover bar 17 moves rightwards, the left-hand tilted edge 21b is caused to slide on the bent edge portion 16b of the left-hand bracket 15b as illustrated in Fig. 1, whereby the left-hand pinch roller 4b is separated from its corresponding capstan 3b. When the changeover bar 17 moves leftwards, the righthand tilted edge 21a is caused to slide on the bent edge portion 16a of the right-hand bracket 15a as illustrated in Fig. 4, whereby the right-hand pinch roller 4a is separated from its corresponding capstan 3a. However, the respective brackets 15a,15b are urged by their corresponding unillustrated springs in such directions that the respective pinch rollers 4a,4b are pressed against their corresponding capstans 3a,3b.

An engagement pin 22 is provided upright at a position on the changeover bar 17. The changeover bar 17 is normally biased rightwards by a tension spring 13.

At a location near the changeover bar 17, a hook member 24 is provided turnably. This hook member 24 has an engagement tab 24a corresponding to the engagement pin 22 and a pressure-receiving portion 24b corresponding to the bent end portion 13b of the lefthand turnable lever 7a, and is urged by a tension spring 25 in a counterclockwise direction as viewed in the drawings.

Of the large diameter gears 8a,8b and small diameter gears 9a,9b which in combination constitute the rotation transmitting units, the large diameter gears 8a,8b are maintained in meshing engagement with the small diameter gears 5a,5b while the small diameter gears 9a,9b are selectively engageable with large diameter gears 26a,26b provided coaxially with the reel shafts 1a,1b. By the way, the meshing engagement between the gears 9a and 26a and that between the gears 9b and 26b are controlled respectively by the turning movements of the turnable levers 7a,7b. Both of the turnable levers 7a,7b are however urged by their corresponding tension springs 27a,27b in such directions that the gears 9a,9b are brought into meshing engagement with their corresponding gears 26a,26b.On the other hand, the turning movements of the turnable levers 7a,7b are controlled by the horizontal movement of the changeover bar 17. The turnable levers 7a,7b and changeover bar 17 are linked together in such a way that while one of the gears (for example, the righthand gear 9a) is maintained in meshing engagement with the gear 26a, the other gear 9b is maintained out of engagement from from the gear 26b.

Mounted on the reel shafts 1a,1b are rotary members 28a,28b which rotate together with their corresponding reel shafts 1a,1b. Pin-like pushing and urging portions 29a,29b are fixedly provided on the rotary members 28a,28b respectively. Friction mechanisms (not shown) are interposed between the reel shafts 1a,1b and the rotary members 28a,28b and between the reel shafts 1a,1b and the large diameter gears 26a,26b respectively. For example, the large diameter gear 26a can still be allowed to rotate even when the rotation of the reel shaft la is stopped. In this case, the corresponding friction mechanism undergoes slipping.

Designated at numeral 30 is a fixing plate, on which cam followers 31a,31b and auxiliary holding members 32a,32b are pivotally supported.

The cam followers 31a,31b have contact portions 33a,33b at locations farthest from their fulcrums, pressure receiving portions 34a,34b located respectively on the orbits of revolutions of the pushing and urging portions 29a,29b, and elastic fingers 35a,35b in the vicinity of the fulcrums.

On the other hand, the auxiliary holding members 32a,32b have a substantially L-like configuration. Lower arms 36a,36b are located outside the shafts 10a,10b, while upper arms 37a,37b are positioned in opposition to the elastic fingers 35a,35b of the cam followers 31a,31b.

Numeral 38 indicates a stop lever provided displaceably back and forth across the changeover bar 17. The stop lever 38 serves as an interlocking member for determining the starting side of a cassette. The stop lever 38 has a bulge 39 at a part of the upper surface thereof and is normally biased in the retreating direction. When this stop lever 38 is caused to advance or retreat, the bulge 29 slides onto the lower surface of the turning end portion of the hook member 24 and lifts the hook member 24 in an upward direction as illustrated in Fig. 5. If the engagement pin 22 of the changeover bar 17 is in engagement with the engagement tab 24a of the hook member 24 at this time, their engagement is released owing to the upward displacement of the hook member 24.

The operation of the automatic reverse mechanism according to the first embodiment of this invention will next be described.

In Fig. 1, the magnetic head 2 is held at the play position and at the same time, the righthand pinch roller 4a is pressing the capstan 3a and the rotation of the capstan 3a, the direction of which is indicated by an arrow, is being transmitted via the gears 5a,8a,9a,26a and the unillustrated friction mechanism to the right-hand reel shaft 1a so that a playback operation is being performed (note: the magnetic tape is omitted in the drawing).

At this time, the rotary force of the reel shaft 1a is being transmitted to the cam follower 31a by way of the pushing and urging portion 29a, whereby the contact portion 33a of the cam follower 31a is maintained in sliding contact with the cam surface 1 Ia. So long as the contact portion 33a is maintained in sliding contact with the cam surface 1 1a in the above-described manner, the contact portions 33a is maintained out of contact with the cam 12a.

Since the left-hand reel shaft 1 b serves as the paying-out side while the playback operation is performed with the tape being taken up on the right-hand reel shaft 1a in the above-described manner, the pushing and urging portion 29b is not pressing the pressurereceiving portion 34b of the cam follower 31b. In this state, the left-hand rotation transmitting unit (gears 8b,9b) has however been separated from the large diameter gear 26b to the non-engagement position relative to the reel shaft 1 b. Accordingly, the lower arm 36b is being pressed by the auxiliary holding member 32b.As a result, the upper arm 37b of the auxiliary holding member 32b is pressing the elastic finger 35b of the cam follower 31b so that the auxiliary holding member 32b in place of the pushing and urging portion 29b maintains the contact portion 33b of the cam follower 31b in sliding contact with the cam surface 1 lb.

When the tape has been fully wound up on the right-hand reel, slipping is developed in the friction mechanism interposed between the large diameter gear 26a and the reel shaft 1a so that the reel shaft la stops. The contact portion 33a which has been kept in sliding contact with the cam surface 1 lea is hence separated from the cam surface 1 lea at a location where the contact portion 33a is closest to the shaft 10a and as illustrated in Fig. 2, the pushing and urging portion 12a is brought into contact with the contact portion 33a.

Since the fulcrum of the cam follower 31a does not move, the rotation transmitting member, namely, the turnable lever 7a is hence caused to turn against the force of the spring 27a so that the gear 9a is separated from the large diameter gear 26a. As a result, the transmission of the rotary force to the large diameter gear 26a is stopped.

On the other hand, a turning movement of the turnable lever 7a causes the bent end portion 13a thereof to press the lug 19 of the changeover bar 17 from the right as shown in Fig. 3, thereby moving the changeover bar 17 leftwards. As a result, the engagement pin 22 provided on the changeover bar 17 is brought into engagement with the engagement tab 24a of the hook member 24 (see, Fig. 4).

Here, the left-hand inclined edge 21b of the change-over bar 17 releases the bracket 1-5b as depicted in Fig. 4. Conversely, the righthand inclined edge 21a causes the bracket 15a to turn in a direction opposite to its biased direction. As a result, the left-hand pinch roller 4b is pressed against the capstan 3b while the right-hand pinch roller 4a is separated from the capstan 3a.

Further, the left-hand turnable lever 7b ispulled by the spring 27b and is hence caused to turn clockwise, whereby the small diameter gear 9b is brought into meshing engagement with the large diameter gear 26b in the same rotation transmitting unit.

As shown in Fig. 4, the automatic reverse mechanism therefore is brought into a state opposite to the state illustrated in Fig. 1.

Hence, the left-hand reel shaft 1 b is caused to rotate in the winding direction and a playback or recording operation is performed while the tape is being wound up on the left-hand reel.

When the tape has been taken up fully on the left-hand reel in the above-described manner, slipping takes place in the unillustrated friction mechanism interposed between the large-diameter gear 26b and reel shaft 1b so that the reel shaft 1 b stops. Accordingly, the contact portion 33b which has been kept in sliding contact with the cam surface 11 b is caused to move closest to the shaft 10b and is then separated from the cam surface Ilb, and similar to the operation shown in Fig. 2, the cam 12b is brought into contact with the contact portion 33b. Since the fulcrum of the cam follower 31b does not move, the rotation transmitting unit, i.e., the turnable lever 7b is caused to turn against the force of the spring 27b so that the gear 9b is separated from the large diameter gear 26b.As a result, the transmission of the rotary force to the large diameter gear 26b is stopped (see, Fig. 1).

On the other hand, the bent end portion 13b of the turnable lever 7b presses the pressure receiving portion 24b of the hook member 24 from the left by the counterclockwise rotation of the turnable lever 7b, whereby the hook member 24 is caused to turn so as to release the engagement pin 22 from the engagement tab 24a. The changeover bar 17 is hence allowed to return in the rightward direction owing to the provision of the tension spring 23. As a consequence, the right-hand inclined edge 21a of the changeover bar 17 releases the bracket 15a as depicted in Fig. 1 while the left-hand inclined edge 21b causes the bracket 15b to turn in a direction opposite to the biased direction. The right-hand pinch roller 4 is therefore pressed against the capstan 3a and the left-hand pinch roller 4b is separated from the capstan 3b.

Further, the right-hand turnable lever 7a is pulled by the spring 27a and is caused to turn counterclockwise, whereby the small diameter gear 9a is brought into meshing engagement with the large diameter gear 26 in the same rotation transmitting unit and the tap is again caused to run in the rightward direction.

When it is desired to stop the playback operation, it is only necessary to push the stop lever 38. By this operation, the magnetic head 2 is caused to return to the stop, namely, eject position from the play position and at the same time, the tape-driving motor is stopped, thereby bringing the tape recorder into a stopped state. Description of this mechanism is however omitted here because it is commonly known.

On the other hand, the pushing of the stop lever 38 causes the bulge 39 provided with the stop lever 38 to slide onto the lower surface of the hook member 24 so that the hook member 24 is lifted as depicted in Fig. 5. If the automatic reverse device is at this time in the state shown in Fig. 4 in which the engagement pin 22 is maintained in engagement with the engagement tab 24a and the changeover bar 17 has been moved in the leftward direction, the engagement pin 22 is released from the engagement tab 24a by the upward displacement of the hook member 24 as a result of the sliding contact of the bulge 39 so that the changeover bar 17 is allowed to return in the rightward direction. Therefore, the tap is always allowed to run in the leftward direction when the next playback or recording operation is started.

The stop lever 38 has been described in the first embodiment as one example of the interlocking member for determining the starting side of the cassette. It is also possible provide a play lever or recording lever with a function to release the hook member 24, so that when the previous operation was stopped during the rotation of the left-hand reel shaft, the changeover bar 17 is changed over in the rightward direction at the same time as the pushing of the play lever or recording lever.

Fig. 6 to Fig. 10 illustrate the automatic reverse mechanism according to the second embodiment of this invention, which is suitable for use in a tape recorder. The same elements of structure as those depicted in Fig. 1 to Fig.

5 are identified by the same reference numerals. Description of the same elements of structure is therefore omitted herein.

In the second embodiment, a two-state lever 125 which is pivotal in a two-state fashion between paired stopper pins 123 and 124 by a toggle spring 122 is provided in the vicinity of one end of the changeover bar 17 as shown in Fig. 6. These two-state lever 125 and toggle spring 122 constitute a pinch roller changeover mechanism together with the changeover bar 17. When the changeover bar 17 has moved, for example, in the leftward direction and the two-state lever 125 has been turned to a point beyond the neutral point, the changeover bar 17 is moved further in the leftward direction owing to the turning force of the two-state lever 125, whereby the right-hand pinch roller 4a is separated from the capstan 3a.

On the other hand, the magnetic head 2 is provided on a head mounting plate 138 which is displaceable back and forth in a direction perpendicular to the longitudinal direction of the changeover bar 17. The head mounting plate 138 is biased normally in the retreating direction (towards the stop, i.e., eject position) by means of two torsion springs 139a,139b. An engagement pin 140 as a locked member is provided upright at a rear end position on the upper surface of the head mounting plate 138. The rear end portion of the head mounting plate 138 forms a push button 141.

Underneath the changeover bar 17, there is provided a plate-like lock member 142 which is slidable horizontally in parallel with the changeover bar 17. The lock member 142 has a hook portion 143, which cooperates with the engagement pin 140. A pressure-receiving pin 144 is also provided on the upper surface of the lock member 142 at a position near the hook portion 143. The lock member 142 is normally urged by means of a torsion spring 145 in the rightward direction as viewed in the drawing.

A selector member 146 is also provided at a part of the changeover bar 17 with one end thereof secured pivotally on the changeover bar 17. This selector member 146 has, at the other end thereof a stepped pressing portion 147 which is engageable with the pressurereceiving pin 144. The selector member 146 is pivotally urged by a torsion spring 148 in a direction where the stepped pressing portion 147 is brought into engagement with the pressure-receiving pin 144.

Designated at numeral 149 is a selector lever which is provided displaceably back and forth in a direction perpendicular to the length of the changeover bar 17. This selector lever 149 has a lock pin 150 and is normally urged by a torsion spring 151 in the retreating direction. The lock pin 1150 engages the selector member 146 and holds the selector member 146 at a position where the the selector member 146 is maintained out of engagement from the pressure-receiving pin 144. By pushing the selector lever 149 against the force of the spring 151, the selector member 146 is however caused to turn following the lock pin 150 so that the stepped pressing portion 147 is brought into engagement with the pressurereceiving pin 144 as indicated by an imaginary line in Fig. 6. Incidentally, the selector lever 149 has a hook portion 152 at a position on one of the side edges thereof.By bringing this hook portion 152 into engagement with a spring stud 153 on which the tension spring 151 is hooked, the selector lever 149 is held at its pushed position.

A description will next be made of the operation of the automatic reverse mechanism according to the second embodiment of this invention.

In Fig. 6, the head mounting plate 139 has moved forward and the engagement pin 140 has been brought into engagement with the hook portion 143 of the lock~member 142, whereby the magnetic head 2 is held at the play position thereof. Furthermore, the righthand pinch roller 4a is being pressed against the capstan 3a so that the rotation, the direction of which is indicated by an arrow, of the capstan 3a is transmitted to the right-hand reel shaft 1a by way of the gears 5a,8a,9a,26a and the unillustrated friction mechanisms. Accordingly, a playback mode is being performed there (note: the magnetic tape is omitted in the drawing).

At this time, the rotary force of the reel shaft 1a is transmitted to the cam follower 31a via the pushing and urging portion 29a, thereby bringing the contact portion 33a of the cam follower 31a into sliding contact with the cam surface Ila. So long as the contact portion 33a is maintained in sliding contact with the cam surface 1 1a in the above-described manner, the contact portion 33a and cam 12a are not allowed to contact to each other.

When the playback mode is performed with the tape being wound up on the right-hand reel shaft 1a in the above-described manner, the left-hand reel shaft 1 b serves as a releasing reel shaft. Therefore, the pushing and urging portion 29b is not pressing the pressurereceiving portion 34b of the cam follower 31b. In this state, the left-hand rotation transmitting unit (the gears 8b,9b) have however already separated from the large diameter gear 26 and moved to the non-engagement position relative to the reel shaft 1 b, so that the lower arm 36b of the auxiliary holding member 32b is being pressed by the shaft 10b.The upper arm 37b of the auxiliary holding member 32b is hence pressing the elastic finger 35b of the cam follower 31b, whereby the auxiliary holding member 32b instead of the pushing and urging portion 29b is holding the contact portion 33b of the cam follower 31b in sliding contact with the cam surface Ilb.

When the tape has been fully wound up on the right-hand reel, slipping takes place in the friction mechanism interposed between the large diameter gear 26a and reel shaft 1a so that the reel shaft 1a stops. The contact portion 33a which has been maintained in sliding contact with the cam surface 1 1a is then separated from the cam surface 1 1a at a position closest to the shaft 10a, so that the cam 12a is brought into contact with the contact portion 33a as shown in Fig. 2 of the first embodiment. Since the fulcrum of the cam follower 31 does not move, the rotation transmitting member, namely, the turnable lever 7a is caused to turn against the force of the spring 27a to separate the gear 9a from the large diameter gear 26a. As a result, the transmission of the rotary force to the large diameter gear 26a is stopped.

Further, the turning movement of the turn ble lever 7a causes the bent end portion 13a of the turnable lever 7a to press a lug 19a of the changeover bar 17 form the right as illustrated in Fig. 7, so that the changeover bar 17 is moved in the leftward direction. In response to the leftward movement of the changeover bar 17, the two-state lever 125 is caused to turn clockwise while compressing the toggle spring 122. As soon as the toggle spring 122 is moved beyond the neutral point, the spring force of the spring 122 acts in the direction that the two-state lever 125 is turned further in the clockwise direction.

Hence, the changeover bar 17 is caused to move rapidly in the leftward direction.

At this time, the left-hand inclined edge 21b of the changeover bar 17 releases the bracket 15b as shown in Fig. 8 while the right-hand inclined edge 21a causes the bracket 15a to turn in the direction opposite to its urged direction. As a result, the left-hand pinch roller 4b is pressed against the capstan 3b and the right-hand pinch roller 4a is separated from the capstan 3a.

Further, the left-hand turnable lever 7b is turned clockwise under the pulling force of the spring 27b, whereby the small diameter gear 9b of the rotation transmitting unit is brought into meshing engagement with the large diameter gear 26b in the same rotation transmitting unit.

As illustrated in Fig. 8, the automatic reverse mechanism has thus been brought into a state opposite to that shown in Fig. 6. A playback or recording mode is performed while the left-hand reel shaft 1b is rotating in the winding direction and the tape is being wound up on the left-hand reel.

In the above-described operation, the reversing operation of the magnetic tape is carried out repeatedly. When it is desired to stop this operation, it is only necessary to cause the lock member 142 to move in the leftward direction as viewed in the drawings against the force of the spring 145 by a predetermined stopping operation so that the hook portion 143 is released from the engagement pin 140 to allow the head mounting plate 138 to return to the retreated position.

When it is desired to automatically stop the tape recorder in a playback or recording mode when the magnetic tape has been fully wound up on the right-hand reel, it is only necessary to push the selector lever 149.

When the selector lever 149 is pushed to bring the hook portion 152 into engagement with the spring stud 153 as depicted in Fig.

9, the selector member 146 is caused to turn by the spring 148 following the lock pin 150 so that the stepped pressing portion 147 assumes a position on a side of the pressurereceiving pin 144 provided on the lock member 142.

The magnetic tape is wound fully on the right-hand reel in the above-described state.

When the changeover bar 17 has moved in the leftward direction, the stepped pressing portion 147 pushes the pressure-receiving pin 144 in the leftward direction. Accordingly, the lock member 142 is caused to move leftwards to release the hook portion 143 from the engagement pin 140. As a result, the head mounting plate 138 is hence retreated by the springs 139a,139b so that the magnetic head 2 is caused to return to the stop, i.e., eject position.

Since the changeover bar 17 has moved to the left when the tape recorder was automatically stopped by pushing the selector lever 149, the left-hand reel always serves as a winding reel when a next playback or recording operation is started. Therefore, the magnetic tape runs in the leftward direction.

As an alternative, the play or recording lever may be allowed to return to its original position when the selector member has moved together with the changeover lever (i.e., pinch roller changeover member) to urge the engagement pin (locked portion), whereby the magnetic head is caused to return to its stop, i.e., eject position.

Fig. 11 and Fig. 13 show the third embodiment of this invention. The same elements of structure as those depicted in Fig. 1 to Fig.

10 are identified by the same reference numerals. Description of the same elements of structure is therefore omitted herein.

In the third embodiment, a two-state plate 224 which is pivotal by a toggle spring 222 in a two-state fashion within a range defined by a stopper pin 223 is connected in the vicinity of one end of the changeover bar 17.

These two-state plate 224 and toggle spring 222 constitutes a pinch roller changeover mechanism together with the changeover bar 17. When the changeover bar 17 has moved, for example, in the leftward direction and the two-state plate 224 has turned to a point beyond the neutral point, the changeover bar 17 is moved further in the leftward direction owing to the spring force of the two-state plate 224. As a result, the right-hand pinch roller 4a is separated from the capstan 3a. Namely, they exhibit the same function as the toggle spring 122, stopper pins 123,124 and twostate lever 125 in the second embodiment (see, Fig. 6).

In addition, a tape running direction indicator 225 is fixedly attached to the two-state plate 224. On the outer casing (not illustrated) of the tape recorder, an indicator for indicating the position of the tape running direction indicator 25, in other words, the running direction of the magnetic tape such as "F" and "R" is also provided.

Owing to the above-described construction, the automatic changeover of the running direction of the tape can be performed in the same principle as the second embodiment, namely, the embodiment illustrated in Fig. 6 through Fig. 10. In the third embodiment, the tape running direction indicator 225 is at the "F" position as shown in Fig. 11 while the pinch roller 4a is being pressed against the capstan 3a and the tape is running in the rightward direction. So long as the pinch roller 4b is being pressed against the capstan 3b and the tape is running in the leftward direction, the tape running direction indicator 225 is maintained at the "R" position as depicted in Fig.

12. Since the tape running direction indicator 225 connected to the changeover bar 17 can therefore indicate the running direction of the tape, it is possible to find out immediately in which direction the tape is running, in other words, whether the tape is running leftwards or rightwards by simply taking a look at the tape running direction indicator 225 even in such an application mode that the magnetic tape, reel shafts and the like are not visible from the outside. This is extremely convenient. Moreover, the running direction of the tape can be manually changed over by manually turning the indicator 225 clockwise or counterclockwise as the case may be.

Fig. 13 to Fig. 16 show the fourth embodiment of this invention. The same elements of structure as those depicted in Fig. 11 to Fig.

12 are identified by the same reference numerals. Description of the same elements of structure is therefore omitted herein.

Designated at numeral 238 in Fig. 13 is a head mounting member, which is provided displaceably back and forth in a direction perpendicular to the length of the changeover bar 17. A cam pin 239 projects from an end portion of the head mounting member 238. The cam pin 239 is fit in a cam slot 241 of a fast feeding control member 240 which is provided displaceably in the horizontal direction. The fast feeding member 240 has an engagement jaw 242 at a position near the cam slot 241 and is normally urged by a tension spring 243 in the rightward direction as viewed in the drawing. Owing to the spring force of the spring 243, the head mounting plate 238 is urged toward the play position where the magnetic head 2 is maintained in contact with the magnetic tape.

An engagement pin 244 is provided upright at a central part of the changeover bar 17. As illustrated in Fig. 14 to Fig. 16, one end of an interlocking member 245 is fit over the pin 244. The interlocking member 245 is pivotally supported at a central part thereof on a base (not illustrated) of the tape recorder and is equipped at the other end thereof with a bulge 246.

Numeral 247 indicates a hook member in Fig. 14 to Fig. 17. This hook member 247 defines an engagement recess 248 engageable with the engagement jaw to lock the fast feeding control member 240 at its pushed position, a stopper portion 249 formed in opposition to the engagement recess 248, an inclined edge portion 250 formed in adjacent to the engagement recess 248, a release recess 251 confronting the inclined edge portion 250, a sliding lug 252 located on the moving line of the bulge 246 of the interlocking member 245, and a projection 254 which may be brought into contact with a stopper pin 253 provided on the fixing plate (not shown) so as to limit the range of the turning motion of the hook member 247. The hook member 247 is normally biased by a spring 255 in the counterclockwise direction as viewed in the drawings.

Owing to the above-described construction, the automatic reverse mechanism according to the fourth embodiment of this invention can perform the automatic changeover of the running direction of a tape in the same principle as the mechanism shown in Fig. 11 to Fig.

12.

When it is desired to perform a fast feeding operation of the tape, it can be achieved in the following manner. Namely, the fast feeding control member 240 is pushed as shown in Fig. 15 so that the engagement jaw 242 is brought into engagement with the engagement recess of the hook member 247. Thereafter, the finger is removed from the fast feeding control member 240. Here, the cam pin 239 provided on the head mounting plate 238 moves along the cam slot 241 of the fast feeding member 240 so that the head mounting member 238 is allowed to retreat to separate the magnetic head from the magnetic tape. At the same time, both left-hand and# right-hand brackets 15a,15b cause the pinch rollers 4a,4b to separate from the capstans 5a,5b in response to the retreating motion of the head mounting member 238.As a result, the tape is allowed to run at a fast speed in the same direction so that the fast feeding operation is performed.

In order to have the tape recorder return from this fast feeding mode to the playback or recording mode, there are the following two methods.

When it is desired to return to the playback or recording mode without changing the running direction of the tape, it is necessary to push the fast feeding control member 240 again. As a result, the engagement jaw 242 of the fast feeding control member 240 is released from the engagement recess 248 and is then caused to move into the release recess 251 to assume a position in front of the inclined edge portion 250. Upon simple removal of the finger, the engagement jaw 242 moves along the lower surface of the inclined edge portion 250 so that the engagement jaw 242 separates from the hook member 247, thereby allowing the fast feeding control member 240 to return to the position shown in Fig. 14. Therefore, the tape recorder has been changed from the fast feeding mode to the playback or recording mode again.

When it is desired to change the tape recorder to the playback or recording mode by changing the running direction of the tape on the other hand, it is only necessary to change the tape running direction indicator 225 in the clockwise or counterclockwise direction. Owing to the resulting sliding movement of the changeover bar 17, the interlocking member 245 is caused to rotate. Here, the bulge 246 of the interlocking member 245 is brought into sliding contact with the sliding lug 252 so as to lift the hook member 247. The engagement jaw 242 of the fast feeding control member 240 is hence released from the engagement recess 248 of the hook member 247, thereby allowing the fast feeding control member 240 to return to the position shown in Fig. 15.Since the changeover bar 17 is also moved in the above-described operation, the running direction of the tape is changed over to perform a playback or recording operation.

When such an automatic reverse mechanism is incorporated in a cassette tape recorder, the above-described fast feeding control member 240 may also be provided with the cassette-ejecting function. Namely, it may be designed to allow the fast feeding control member 240 to be pushed beyond its position depicted in Fig. 15 and to actuate the eject mechanism by the extra pushing stroke.

The changeover bar 17 may also be moved by a separate member instead of moving it directly by the members which carry the rotation transmitting units. In addition, the tape running direction indicator 225 is not limited to the pivotal structure shown in the abovedescribed fourth embodiment but may take the horizontally sliding structure or may be composed of a pair of members provided respectively at both ends of the two-state member 224.

In the fourth embodiment, the head mounting member 238 may be replaced by that of the second embodiment so as to incorporate the tension springs 139a,139b, engagement pin 140, push button 141, lock member 142, hook portion 143, pressure receiving pin 144, tension spring 145, selector member 146, stepped pressing portion 147, tension spring 148, selector lever 149, lock pin 150, tension spring 151, hook portion 152 and spring stud 153.

Fig. 18 to Fig. 21 illustrate the fifth embodiment of this invention. In Fig. 18, the righthand reel shaft 1a is rotating. The left-hand reel shaft 1b is rotating in Fig. 21. Fig. 19 and Fig. 20 illustrate the automatic reverse mechanism in the course of its change from the state shown in Fig. 18 to its state depicted in Fig. 21.

In these figures, the same elements of structure as those in the first embodiment (Fig. 1 to Fig. 5) are identified by the same reference numerals. Description of the same elements of structure is therefore omitted herein.

In the fifth embodiment, an eccentric cam surface 11 is formed about the shaft 10a of the large diameter gear 8a on one side only.

In addition, a cam 12 projects from and in continuation with the shaft 10a at the position where the eccentric cam surface 11 has the maximum radius.

Further, an engagement pin 322 projects out from a part of the changeover bar 17. At a position near the changeover bar 17, a hook member 324 is provided turnably. This hook member 324 is urged clockwise as viewed in the drawings by a spring 325 provided at the fulcrum of its pivotal movement.

Numeral 330 indicates a fixing plate, on which a cam follower 331 is pivotally supported. This cam follower 331 has pressure receiving arms 332a,332b corresponding respectively to the pressing and urging members 29a,29b. In addition, a third arm extends toward the eccentric cam surface 11, and a contact portion 333 which can undergo sliding contact with the eccentric cam surface 11 is provided at an end portion of the third arm.

The hook member 324 is provided with its free end directed toward the right. By the spring force of the spring 325, the free end of the hook member 324 is normally maintained in engagement with the engagement pin 322. The hook member 324 defines a locking recess 324 engageable with the engagement pin 322 so as to hold the changeover bar 17 at the leftwardly-moved position thereof, a stopper portion 335 confronting the locking recess 334, an incined portion 336 located in adjacent to the locking recess 334, and a release recess 337 opposing the inclined portion 336.

Designated at numeral 338 is a stop lever provided displaceably back and forth at a right angle with respect to the changeove bar 17.

This stop lever 338 has a bulge 339 at a part of the upper surface thereof and is normally urged in the retreating direction by a torsion spring 340. When this stop lever 338 advances and retreats, the bulge 339 slides on the lower surface of the free end portion of the hook member 324 so as to lift the hook member 324 upwards. If the engagement pin 322 of the changeover bar 17 is in engagement with the locking recess 334 of the hook member 324 at this time, their engagement is released as a result of the upward displacement of the hook member 324.

The operation of the automatic reverse mechanism according to the fifth embodiment will next be described.

In Fig. 18, the magnetic head 2 is maintained at the play position and the right-hand pinch roller 4a is being pressed against the capstan 3a. The rotation of the capstan 3a, the direction of which is indicated by an arrow, is being transmitted to the right-hand reel shaft 1a by way of the gears 5a,8a,9a,26a and the unillustrated friction mechanisms, whereby a playback operation is under way (note: the magnetic tape is omitted in the drawing).

In the above state, the rotary force of the reel shaft la is transmitted to the pressurereceiving arm 332a of the cam follower 331 via the pushing and urging portion 29a so that the contact portion 333 of the cam follower 331 is brought into sliding contact with the cam surface 11. So long as the contact portion 333 is maintained in sliding contact with the cam surface 11 in the above manner, the contact portion 333 and cam 12 are maintained out of contact.

When the tape has been fully wound up on the right-hand reel, slipping takes place in the unillustrated friction mechanism interposed between the large diameter gear 26a and reel shaft la and the reel shaft 1a stops-accordingly. At this time, the contact portion 333 which has been maintained in sliding contact with the cam surface 11 is separated from the cam surface 11 at a position closest to.the shaft 10a and as shown in Fig. 19, the cam 12 is then brought into contact with the contact portion 333. Since the fulcrum of the cam follower 331 does not move, the rotation transmitting unit, namely, the turnable lever 7a is caused to turn against the force of the spring 27a so that the gear 9a is separated from the large diameter gear 26a. As a result, the transmission of the rotary force to the large diameter gear 26a is stopped.

On the other hand, by the turning of the turnable lever 7a, the bent end portion 13a of the turnable lever 7a pushes the lug 19-of the changeover bar 17 from the right whereby the changeover bar 17 is moved in the-leftward direction. As a result, the engagement pin 322 provided on the changeover bar 17 is brought into engagement with the locking recess 332 of the hook member 324 (Fig. 21).

At this time, as shown in Fig. 21, the lefthand inclined edge 21b of the changeover bar 17 releases the bracket 15b while the righthand inclined edge 21a causes the bracket 15a to turn in the direction opposite to its urged direction. As a result, the left-hand pinch roller 4b is pressed against the capstan 3b while the right-and pinch roller 4a is separated form the capstan 3a.

In addition, the left-hand turnable lever 7b is caused to turn clockwise under the pullingforce of the spring 27b, thereby bringing the small diameter gear 9b in the rotation transmitting unit into meshing engagement with the large diameter gear 26b in the same rotation transmitting unit.

As shown in Fig. 21, the automatic reverse mechanism is hence brought into a state opposite to that depicted in Fig. 18 and the lefthand reel shaft 1 b is driven in the winding direction. A playback or recording operation is hence performed while the tape is being taken up on the left-hand reel.

When the tape has been fully wound up on the left-hand reel in the above-described manner, slipping takes place in the unillustrated friction mechanism interposed between the large diameter gear 26b and reel shaft -1 b, resulting in stoppage of the reel shaft 1 b. Accordingly, the contact portion 333 which has been maintained in sliding contact with the cam surface 11 is caused to come closest to the shaft 10a and is then separated from the cam surface 11. Similar to the state shown in Fig. 19, the cam 12 is brought into contact with the contact portion 333. As a result, the turnable lever 7a is turned against the force of the spring 27a and the changeover bar 17 is pushed again in the leftward direction by the bent end portion 13a.As a consequence, the engagement pin 322 is allowed to advance in the locking recess 344 to a position in the release recess 337, said position being located in front of the inclined portion 336.

Upon elimination of the pressing force from the bent end portion 13a, the engagement pin 322 enters underneath the lower surface of the inclined portion 336 so that the changeover bar 17 is allowed to return simply in the rightward direction owing to the pulling force of the tension spring 23. Here, as shown in Fig. 18, the right-hand inclined edge 21a of the changeover bar 17 releases the bracket 15a while the left-hand inclined edge 21b causes the bracket 15b to turn in the direction opposite to its urged direction. As a result, the right-hand pinch roller 4a is pressed against the capstan 3a while the left-hand pinch roller 4b is separated from the capstan 3b.

Furthermore, the right-hand turnable lever 7a is caused to turn counterclockwise under spring force of the spring 27a whereby the small diameter gear 9a in the rotation transmitting unit is brought into meshing engagement with the large diameter gear 26a in the same rotation transmitting unit. As a result, the tap is caused to run rightwards again.

When it is desired to stop the playback operation, it is only necessary to push the stop lever 338. By this operation, the magnetic head 2 is caused to return from the play position to the stop, i.e., eject position and the tape driving motor (not shown) is turned off, so that the tape recorder is stopped. This mechanism is omitted herein because it is commonly known.

When the stop lever 338 is operated on the other hand, the bulge 339 provided on the stop lever 338 slides on the lower surface of the end portion of the hook member 324-so that the hook member 324 is lifted. If the engagement pin 322 is in engagement with the hook member 324 and the changeover bar 17 is in the state moved leftwards as shown in Fig. 21 at this time, the engagement pin 322 is released from the locking recess 334 when the hook member 324 is lifted upwardly owing to the sliding contact of the bulge 339.

As a consequence, the changeover bar 17 is allowed to return in the rightward direction.

The tape always begins to run in the leftward direction when the next playback or recording operation is started. It is hence possible to omit the cumbersome operation to return to the side A even when the contents of information on the sides A and B of a tape is continuous.

As has been described above, the automatic reverse mechanism according to each of the first to fifth embodiments of this invention for a tape recorder does not require accessory parts such as solenoids and hence permits easy size reduction. Since the pinch roller changeover mechanism is actuated by detecting stoppage of the reel shafts without impairing the balance of the flywheels, no false operations are caused to occur even when the tension of a tape becomes temporarily high upon starting the tape recorder.

In the automatic reverse mechanism according to each of the first and fifth embodiment of this invention, the running direction of a tape is always the same upon initiation of each playback operation, recording operation or the like. Even if the contents of information recorded on the sides A and B of a tape are continuous, it is possible to avoid the cumbersome operation to return to the A side before starting a playback operation, recording operation or the like.

Further, the automatic reverse mechanism according to the second embodiment of this invention can also be used as an automatic stopping device by choosing the position of the selector member. It is therefore possible to achieve a variety of functions by the simple structure.

By the automatic reverse mechanism according to the third embodiment of this invention, it is possible to perform with easy the display of the running direction of a tape and manual changeover of the running direction.

The automatic reverse mechanism according to the fourth embodiment permits free changeover from the playback mode to the fast feeding mode, from the fast feeding mode to the playback mode in the same direction, and from the fast feeding mode to the playback mode in the different direction.

The automatic reverse mechanism according to the fifth embodiment can contribute to the materialization of overall simplification.

There has been described an automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at positions other than the centers of the reel shafts; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members to non-engagement positions where the rotation transmitting members are maintained out of engagement with their corresponding reel shafts;; a pinch roller changeover member provided reciprocally but normally biased in one direction, and when one of the rotation transmitting members is displaced to its non-engagement position relative to its corresponding reel shaft, said pinch roller changeover member moving in a direction opposite to said biased one direction in response to the displacement of said one of the rotation transmitting members to the non-engagement position thereof whereby one of the pinch rollers, which is associated with said one of the rotation transmitting members, is brought into contact with its corresponding capstan and the other pinch roller is separated from its corresponding capstan;; a hook member for locking the pinch roller changeover member at a position when the pinch roller changeover member has been displaced to the locked position in the direction opposite to said biased one direction, and when the other rotation transmitting member is displaced to its non-engagement position relative to its corresponding reel shaft, releasing the pinch roller changeover members from the locked position in response to the displacement of the other rotation transmitting member; and an interlocking member for determining the starting side of the cassette, said interlocking member being operative in association with a stopping operation or a playback or recording starting operation of the tape recorder and when the pinch roller changeover member is locked by the hook member, shifting the hook member so as to release the pinch roller changeover member from the hook member.

There has also been described an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members to non-engagement positions where the rotation transmitting members are maintained out of engagement with their corresponding reel shafts;; a pinch roller changeover member capable of moving, in response to each displacement of either one of the rotation transmitting members to its non-engagement position relative to its corresponding reel shaft in a direction toward the side of the other rotation transmitting member, whereby one of the pinch rollers, which is associated with the other rotation transmitting member, is brought into contact with its corresponding capstan and the other pinch roller is separated from its corresponding capstan; a locked member capable of displacing in association with each displacement of the magnetic head from its eject position to its playback or recording position;; a lock member for locking the locked member at a predetermined position so as to maintain the magnetic head at the playback or recording position thereof or releasing the locked member from the predetermined position so as to allow the magnetic head to return to the eject position thereof; and a selector member mounted on- the pinch roller changeover member in such a way that the selector member can selectively assume either one of two positions, said selector member being adapted to displace the lock member and to release the lock member from the locked member only when the pinch roller changeover member moves toward either one of both sides relative to the magnetic head while the selector member assumes selectively one of the two positions thereof.

There has also been described an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated, being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members from their respec tive rotation transmitting positions where the rotation transmitting members transmit the rotary forces of the capstans to their corresponding reel shafts;; a pinch roller changeover member for bringing, in response to each displacement of either one of the rotation transmitting members from the rotation transmitting position thereof, one of the pinch rollers, which is associated with said one of the rotation transmitting members, into contact with its corresponding capstan and separating the other pinch roller from its corresponding capstan and a tape running direction indicator connected to the pinch roller changeover member and being capable of assuming either one of predetermined two positions in accordance with the position of the pinch roller changeover member so as to indicate the running direction of the tape.

There has also been described an automatic reverse mechanism for a tape recorder in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at eccentric positions thereof; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; eccentric cam surfaces and cams provided respectively about the shafts of the rotation transmitting members;; cam followers arranged symmetrically relative to the magnetic head, said cam followers having contact portions at one parts thereof, and while the reel shafts are being rotated being urged by their corresponding pushing and urging portions so as to maintain the contact portions in sliding contact with the corresponding cam surfaces and hence to maintain the contact portions out of contact with their corresponding cams, but when the reel shafts are stopped and the contact portions assume positions apart from the cam surfaces due to elimination of the urging forces of the pushing and urging portions, being brought into contact at the contact portions thereof with the corresponding cams so as to displace the rotation transmitting members from their respective rotation transmitting positions where the rotation transmitting members transmit the rotary forces of the capstans to their corresponding reel shafts;; a pinch roller changeover member for bringing, in response to each displacement of either one of the rotation transmitting members from the rotation transmitting position thereof, one of the pinch rollers, which is associated with said one of the rotation transmitting members, into contact with its corresponding capstan and separating the other pinch roller from its corresponding capstan and a head mounting member supporting themagnetic head thereon, said head mounting member being provided displaceably between a play position where the magnetic head is maintained in contact with the magnetic tape and a position other than the play position, where the magnetic head is separated from the magnetic tape, and being capable of separating the pinch rollers from their corresponding capstans on both sides of the magnetic head when the head mounting member moves from the play position toward the latter position; a tape running direction changeover member adapted to manually advance or retreat the pinch roller changeover member so as to change the running direction of the magnetic tape; a fast-forward feeding member connected to the heat mounting member and normally biasing the head mounting member from the position other than the play position toward the play position, and when pushed manually, being capable of retreating the head mounting member toward the position other than the play position whereby the tape recorder is rendered ready to perform a fast-forward mode; ; a hook member adapted to hold the fastforward feeding member at a pressed position to maintain the tape recorder in the fast-forward mode when the fast-forward feeding member has been pressed manually to the pressed position, and to release the fast-forward feeding member from the pressed position when the fast-forward feeding member is pressed again; and an interlocking member for causing the hook member to release the fast-forward feeding member in response to each actuation of the tape running direction changeover member.

There has also been described an automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged respectively on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a cassette inserted in the tape recorder to run toward the rotating reel shaft, and when the magnetic tape has been fully wound up on the rotating reel shaft, the running direction of the magnetic tape is automatically changed over, comprising:: pushing and urging portions provided on the respective reel shafts at positions other than the centers of the reel shafts; rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being normally rotated about their corresponding shafts under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via corresponding friction mechanisms; an eccentric cam surfaceand cam provided about a rotary shaft of one of the rotation transmitting members;; a cam follower having a contact portion at one part thereof and being urged against the pushing and urging portion on the side of the reel shaft, which is rotating in the tape-winding direction, so as to maintain the contact portion thereof in sliding contact with the cam surface and hence to maintain the contact portion out of contact with the cam, but when the reel shaft is stopped and the contact portion assumes a position apart from the cam surface due to elimination of the urging force of the pushing and urging portion, being brought into contact at the contact portion thereof with the cam so as to displace the rotation transmitting member to a non-engagement position where the rotation transmitting member is maintained out of engagement with the stopped reel shaft;; a pinch roller changeover member provided reciprocally but normally biased in one direction, and when the rotation transmitting member equipped with the eccentric cam surface is displaced to its non-engagement position relative to its corresponding reel shaft, said pinch roller changeover member moving in a direction opposite to said biased one direction in response to the displacement of the rotation transmiNting member- equipped with the eccentric cam surface so as to move the other rotation transmitting member to the engagement position thereof relative to its corresponding reel shaft whereby one of the pinch rollers, which is associated with the other rotation transmitting member, is brought into contact with its corresponding capstan and the rotation transmitting member equipped with the eccentric cam surface is separated from its corresponding capstan; and a hook member for locking the pinch roller changeover member at a position when the pinch roller changeover member has been displaced to the locked position in the direction opposite to said biased one direction upon receipt of a moving force of the rotation transmitting member equipped with the eccentric cam surface, and when the pinch roller changeover member has received a moving force of the rotation transmitting member equipped with the eccentric cam surface, releasing the pinch roller changeover member from the locked position.

Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.

Claims

1. An automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged symmetrically on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a tape cassette inserted in the tape recorder to run in one direction, and when the magnetic tape has been fully wound up, the running direction of the magnetic tape is automatically changed over, comprising:: a rotation transmitting means having a pair of rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being rotated normally under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via friction mechanisms respectively; an eccentric circular cam surface provided eccentrically about a rotary shaft of at least one of the rotation transmitting members, and an engagement portion provided with said at least one rotation transmitting member; a reel-shaft stop detecting means for detecting each stop of at least one of the reel shafts, said means having a cam follower portion and a contact portion and adapted to receive a rotary force of said at least one reel shaft via a friction mechanism; said cam follower being maintained in sliding contact with the eccentric circular cam surface so as to avoid engagement between the contact portion and the engagement portion and when said at least one reel shaft stops, remaining at a position apart from the eccentric circular cam surface, whereby the contact portion is allowed to engage the engagement portion and at the same time said at least one rotation transmitting member is displaced from an engagement position to a non-engagement position relative to the corresponding reel shaft by a turning force developed in said at least one rotation transmitting member; and a reversing means operable responsive to each displacement of said at least one rotation transmitting member to the non-engagement position so that the pinch roller associated with said at least one rotation transmitting member is separated from its corresponding capstan, the other pinch roller is brought into contact with the other rotation transmitting member, and the other rotation transmitting member is displaced to an engagement position relative to its corresponding reel shaft.

2. The automatic reverse mechanism as claimed in Claim 1, wherein the cam follower portion also serves as the contact portion.

3. The automatic reverse mechanism as claimed in Claim 1, wherein the rotation transmitting means includes, in addition to said pair of rotation transmitting members, a pair of turnable members which are arranged symmetrically relative to the magnetic head, are turnable respectively about predetermined central axes, carry the corresponding rotation transmitting members rotatably thereon, and are connected at one ends thereof to the reversing means.

4. The automatic reverse mechanism as claimed in Claim 3, wherein the reel-shaft stop detecting means comprises, with respect to each of the reel shafts, a pushing and urging member provided at a position other than the center of the corresponding reel shaft and adapted to receive a rotary force of the corresponding reel shaft via the associated friction mechanism, and a cam follower member and auxiliary holding member both supported pivotally; the cam follower member has the corresponding cam follower portion and contact portion, a pressure receiving portion positioned on the path of rotation of the pushing and urging member, and an elastic finger; and the auxiliary holding member has two arms, one located outside the rotary shaft of the corresponding rotation transmitting member and the other facing the elastic finger of the corresponding cam follower member.

5. The automatic reverse mechanism as claimed in Claim 3, wherein the reel-shaft stop detecting means is equipped with pushing and urging members, which are provided at positions other than the centers of the respective reel shafts and are adapted to receive rotary forces of theu respective reel shafts via the associated friction mechanisms, and a cam follower common to both reel shafts, said cam follower being supported pivotally; and the cam follower member has two pressurereceiving portions, which correspond to the pushing and biasing members respectively, the cam follower portion, and the contact portion.

6. The automatic reverse mechanism as claimed in Claim 3, wherein the eccentric circular cam surface is an inner peripheral wall of a recess formed around the rotary shaft of the rotation transmitting member and the engagement portion is provided as an engaging projection in the recess.

7. The automatic reverse mechanism as claimed in Claim 3, wherein the reversing means comprises a changeover bar, which is connected to both turnable members and displaceable reciprocally between a first position and second position, and a toggle spring for biasing the changeover bar selectively to either the first or the second position in cooperation with the turnable members.

8. The automatic reverse mechanism as claimed in Claim 7, wherein a manually-operable member is interposed between the changeover bar and the toggle spring.

9. The automatic reverse mechanism as claimed in Claim 8, wherein the manually-operable member also serves as a member for indicating the running direction of the magnetic tape.

10. An automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged symmetrically on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a tape cassette inserted in the tape recorder to run in one direction, and when the magnetic tape has been fully wound up, the running direction of the magnetic tape is automatically changed over, comprising:: a rotation transmitting means having a pair of rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being rotated normally under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via friction mechanisms respectively; an eccentric circular cam surface provided eccentrically about a rotary shaft of at least one of the rotation transmitting members, and an engagement portion provided with said at least one rotation transmitting member; a reel-shaft stop detecting means for detecting each stop of at least one of the reel shafts, said means having a cam follower portion and a contact portion and adapted to receive a rotary force of said at least one reel shaft via a friction mechanism; said cam follower being maintained in sliding contact with the eccentric circular cam surface so as to avoid engagement between the contact portion and the engagement portion and when said at least one reel shaft stops, remaining at a position apart from the eccentric circular cam surface, whereby the contact portion is allowed to engage the engagement portion and at the same time said at least one rotation transmitting member is displaced from an engagement position to a non-engagement po sition relative to the corresponding reel shaft by a turning force developed in said at least one rotation transmitting member;; a reversing means operable responsive to each displacement of said at least one rotation transmitting member to the non-engagement position so that the pinch roller associated with said at least one rotation transmitting member is separated from its corresponding capstan, the other pinch roller is brought into contact with the other rotation transmitting member, and the other rotation transmitting member is displaced to an engagement position relative to its corresponding reel shaft; and a means for determining the starting side of the tape cassette by controlling the reversing means in such a way that an operating mode of the tape recorder is released to stop the tape recorder and responsive to the stop of the tape recorder one of the rotation transmitting members, said one rotation transmitting member being on a predetermined side, is displaced to the engagement position relative to the corresponding reel shaft.

11. The automatic reverse mechanism as claimed in Claim 10, wherein the rotation transmitting means includes, in addition to said pair of rotation transmitting members, a pair of turnable members which are arranged symmetrically relative to the magnetic head, are turnable respectively about predetermined central axes, carry the corresponding rotation transmitting members rotatably thereon, and are connected at one ends thereof to the reversing means.

12. The automatic reverse mechanism as claimed in Claim 11, wherein the reversing means comprises a changeover bar connected to both turnable members and displaceable reciprocally between a first position and second position, a spring for biasing the changeover bar toward the first position, and a hook for holding the changeover bar, which has been displaced by one of the rotation transmitting members toward the second position against the spring, so as to hold the changeover bar at the second position and for releasing its engagement with the changeover bar located at the second position by the other rotation transmitting member and the starting-side determining means.

13. The automatic reverse mechanism as claimed in Claim 12, wherein the starting-side determining means comprises a means for stopping the operation of the tape recorder and a release means for releasing the changeover bar from the hook by an action of the stopping means.

14. The automatic reverse mechanism as claimed in Claim 13, wherein the release means is a projection for lifting the hook, which has engaged a pin provided upright on the changeover bar and is holding the changeover bar at the second position, responsive to the stop means, whereby the engagement between the hook and pin is released.

15. An automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged symmetrically on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a tape cassette inserted in the tape recorder to run in one direction, and when the magnetic tape has been fully wound up, the running direction of the magnetic tape is automatically changed over, comprising:: a rotation transmitting means having a pair of rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being rotated normally under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via friction mechanisms respectively; an eccentric circular cam surface provided eccentrically about a rotary shaft of at least one of the rotation transmitting members, and an engagement portion provided with said at least one rotation transmitting member; a reel-shaft stop detecting means for detecting each stop of at least one of the reel shafts, said means having a cam follower portion and a contact portion and adapted to receive a rotary force of said at least one reel shaft via a friction mechanism; said cam follower being maintained in sliding contact with the eccentric circular cam surface so as to avoid engagement between the contact portion and the engagement portion and when said at least one reel shaft stops, remaining at a position apart from the eccentric circular cam, whereby the contact portion is allowed to engage the engagement portion and at the same time said at least one rotation transmitting member is displaced from an engagement position to a non-engagement relative to the corresponding reel shaft by a turning force developed in said at least one rotation transmitting member;; a reversing means operable responsive to each displacement of said at least one rotation transmitting member to the non-engagement position so that the pinch roller associated with said at least one rotation transmitting member is separated from its corresponding capstan, the other pinch roller is brought into contact with the other rotation transmitting member, and the other rotation transmitting member is displaced to an engagement position relative to its corresponding reel shaft; and a means for determining the starting side of the tape cassette by controlling the reversing means in such a way that an operating mode of the tape recorder is released to stop the tape recorder and responsive to the stop of the tape recorder one of the rotation transmitting members, said one rotation transmitting member being on a predetermined side, is displaced to the engagement position relative to the corresponding reel shaft;; wherein the rotation transmitting means includes, in addition to said pair of rotation transmitting members, a pair of turnable members which are arranged symmetrically relative to the magnetic head, are turnable respectively about predetermined central axes, carry the corresponding rotation transmitting members rotatably thereon, and are connected at one ends thereof to the reversing means, and the starting-side determining means is equipped with a reverse mode selector means which permits manual selection of either one of two positions and stops an operation of the tape recorder responsive to a displacement of one of the turnable members only at one of the two positions.

16. The automatic reverse mechanism as claimed in Claim 15, wherein the reversing means comprises a changeover bar connected to both turnable members and displaceable reciprocally between a first position and second position, a spring for biasing the changeover bar toward the first position, and a hook for holding the changeover bar, which has been displaced by one of the rotation transmitting members toward the second position against the spring, so as to hold the changeover bar at the second position and for releasing its engagement with the changeover bar located at the second position by the other rotation transmitting member and the starting-side determining means; and the reverse mode selector means is equipped with a selector member mounted on the changeover bar in such a state that the selector member can select either one of two positions, and the selector member causes the magnetic head to return to a stop position only when the changeover bar moves in one direction in a state that one of the positions has been selected.

17. An automatic reverse mechanism for a tape recorder, in which capstans, pinch rollers and reel shafts are arranged symmetrically on both sides of an associated magnetic head, the capstans on both sides of the magnetic head and either one of said reel shafts are normally driven and rotated, the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan to cause the magnetic tape of a tape cassette inserted in the tape recorder to run in one direction, and when the magnetic tape has been fully wound up, the running direction of the magnetic tape is automatically changed over, comprising:: a rotation transmitting means having a pair of rotation transmitting members arranged symmetrically relative to the magnetic head, said rotation transmitting members being rotated normally under rotary forces of the corresponding capstans so as to transmit the rotary forces to the corresponding reel shafts via friction mechanisms respectively; an eccentric circular cam surface provided eccentrically about a rotary shaft of at least one of the rotation transmitting members, and an engagement portion provided with said at least one rotation transmitting member; a reel-shaft stop detecting means for detecting each stop of at least one of the reel shafts, said means having a cam follower portion and a contact portion and adapted to receive a rotary force of said at least one reel shaft via a friction mechanism; said cam follower being maintained in sliding contact with the eccentric circular cam surface so as to avoid engagement between the contact portion and the engagement position and when said at least one reel shaft stops, remaining at a position apart from the eccentric circular cam surface, whereby the contact portion is allowed to engage the engagement position and at the same time said at least one rotation transmitting member is displaced from an engagement position to a non-engagement position relative to the corresponding reel shaft by a turning force developed in said at least one rotation transmitting member;; a reversing means operable responsive to each displacement of said at least one rotation transmitting member to the non-engagement position so that the pinch roller associated with said at least one rotation transmitting member is separated from its corresponding capstan, the other pinch roller is brought into contact with the other rotation transmitting member, and the other rotation transmitting member is displaced to an engagement position relative to its corresponding reel shaft; a fast forward feeding member for causing the magnetic head to retreat when the fast forward feeding member is manually pushed in a playback mode; ; a lock means for holding the fast forward feeding member at a pushed position upon manual pushing of the fast forward feeding member, said lock means releasing the holding of the fast forward feeding member when the fast forward feeding member is pushed again; and a fast forward feeding release means for releasing the holding of the fast forward feeding member responsive to an operation of the reversing means when the fast forward feeding member is held at its pushed position by the lock means.

18. An automatic reverse mechanism for a tape recorder substantially as any one of the specific embodiments hereinbefore described with reference to, and as shown in, the accompanying drawings.