GB2157875A - Tape player - Google Patents

Abstract

A cassette tape player enables a magnetic tape to be played in both directions without being removed from the player. A pivotable carriage 20 carries two tape heads 22 and is arranged to swing the tape head which is upstream of the rotating capstan 8 into its reading position. It is also arranged that the capstan 8 causes take-up wheels 36 both upstream and downstream of the capstan to rotate, but urges only the downstream wheel into engagement with the spool of the tape. <IMAGE>

Description

SPECIFICATION Tape player This invention relates to a tape player which can be played in both directions without removing the tape from the player.

According to the present invention there is provided a tape player for playing a magnetic tape in both directions without removing the tape from the play, comprising a reversible drive motor rotating a capstan upon which a tape pinch wheel bears when the tape is played, a carriage carrying two tape playback heads, the carriage being pivotable about a pivot axis substantially parallel to the axis of rotation of the capstan at a position intermediate the heads, means responsive to the direction in which the motor rotates the capstan for swinging the carriage about its pivot axis so that the playback head upstream of the capstan is moved into a tape reading position, and tape take-up means responsive to the direction in which the motor rotates the capstan whereby a tape spool downstream of the capstan can be rotated so that the tape winds onto it.

In our preferred embodiment the tap pinch wheel is a part of a tape cassette rather than of the tape player.

Preferaly the tape take-up means comprises a take-up wheel on each side of the carriage, one take-up wheel being engageable with one tape spool and the other take-up wheel being engageable with the other tape spool wherein both take-up wheels are rotated when the capstan is rotated but only the take-up wheel downstream of the capstan is moved to a position in which it engages its tape spool.

The take-up means may further comprise a first gear wheel rotated by the motor on a shaft having a fixed axis, a second gear wheel driven by the first gear wheel and disposed on a shaft on which the take-up wheel is disposed, wherein the respective shafts of the gear wheels are journalled in a bracket which is free to turn about the fixed axis of the first gear wheel, whereby rotation of the first gear wheel causes the take-up wheel to rotate and urges it to move transverse to its axis on the arc of a circle centred on the axis of the first gear wheel.

Preferably a tape player embodying the invention has a fast speed mode in which the pinch wheel is held away from the capstan and the take-up wheel engages the tape spool onto which tape is to be wound, the take-up means comprising an input wheel receiving drive from the motor, and a play wheel and a fast speed wheel alternatively operable to transmit drive from the input wheel to the take-up wheel.

The drive to each take-up wheel when the tape player is in its play mode is preferably through a slipping clutch whereby the correct take-up tension is applied to the tape.

Preferably the means for swinging the carriage about its axis comprises a slipping clutch having a rotating member which rotates the capstan and a part engaged with the carriage and movable with the rotating member between positions which correspond to the two extreme positions of the carriage.

The invention provides a tape player which can play a tape in both directions without removing the tape from the player and in which there may be no impediment to the movement of tape downstream from the capstan. The latter feature is of considerable significance since the take-up tension of the tape is an important parameter in the operation of the player.

The invention provides a reversible drive tape player in which the reversibility arises from the use of simple mechanical parts. The use of heavy, power consuming components such as solenoids can thereby be avoided. A tape player constructed according to the present invention can thus be readily portable.

One embodiment of the invention will now be further described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a plan view of the drive mechanism of a tape player; Figure 2 is a view of the drive mechanism from below; Figure 3 is a side elevation of the tape takeup mechanism, viewed in the direction indicated by the arrow A in Fig. 1; and Figure 4 shows our standard design of tape cassette, for use with which the tape player to be described is adapted.

The tape player comprises a constant speed reversible electric motor 2 driving a flywheel 4 through a belt 6. The flywheel 4 carries the capstan 8, which is in the form of a pin or spindle. When the capstan rotates and is engaged by a pinch wheel 10 in the cassette 12 (see Fig. 4) tape is drawn between the capstan and the pinch wheel at constant linear velocity.

Pulley wheels 14 are coaxial with the capstan 8 and are likewise rotated by the flywheel 4. Drive is transmitted via crossedover belts 16 to tape take-up mechanisms 18 on each side of the capstan 8.

As shown in Fig. 2, the drive mechanism includes a carriage 20 which carries two tape playback heads 22. The carriage can pivot about a pivot axis 24 which is in transverse alignment with the capstan 8 and is disposed between the tape take-up mechanism. The playback heads are disposed on either side of the pivot axis 24 and are mutually vertically displaced by the distance between two adjacent tracks on the magnetic tape.

The carriage 20 also carries a bracket 26 having a U-shaped portion 28 spaced from the pivot axis 24, and in which a pin 30 is engaged. The pin 30 is attached to a disc which is a part of a slipping clutch. The freely rotating part of the clutch is the, flywheel 4.

When the flywheel rotates the disc rotates with it until the pin 30 on the disc is obstructed by a stop (not shown). The clutch now slips, nd the flywheel continues to rotate.

The movement of the pin causes the carriage to swing about its pivot and bring the playback head upstream of the capstan to adopt its playback position. The other playback head is held away from the tape. When the motor reverses the carriage is now swung so that the other playback head adopts its playback position. Because the rotation of the capstan has reversed the playback head in use is still upstream of it.

Each tape take-up mechanism has an input wheel in the form of a pulley wheel 32 engaged with the belt 16, a slipping clutch 34 driving a take-up wheel 36 which is engageable with a tape spool, and, engageable alternatively to one another to transmit drive from the pulley wheel 32 to the take-up wheel 36, a play wheel 38 or a fast speed wheel 40. The play wheel 38 is engageable between the pulley wheel 32 and the movable wheel 48 of the clutch 34 whilst the fast speed wheel 40 is engageable between the pulley wheel 32 and a wheel 46 fixed to the output shaft 52 of the clutch so that drive in the fast speed mode is not through the slipping clutch 34.

The play and fast speed wheels 38 and 40 are mounted on a speed change platform 42 which may move relative to the remainder of the take-up mechanism about a pivot point 44 so that the required wheel may be brought into use. The platform 42 may be slotted where the shaft 45 leading from the pulley wheel passes through it to allow this relative movement. The wheels 38 nd 40 operate between wheels of different diameter so that the take-up wheel 36 is caused to rotate rapidly when the advanced speed wheel is used. Thus, the fast speed wheel 40 engages a larger diameter portion of the shaft 45 of the pulley wheel 32 than the play wheel 38, and the wheel 46 fixed on the output shaft 52 of the clutch is of smaller diameter than the movable wheel 48 of the clutch, with which the play wheel 38 engages. The fixed part of the clutch, on which movable part 48 slips, is shown at 50.

The output shaft 52 of the clutch 34 is journalled in a fixed bearing bracket 54 and is thereby restrained against transverse movement. It is also journalled in a U-shaped bracket 56 and carries a gear wheel 58 within the 'U'. Meshing with the gear wheel 58 is a gear wheel 60 on the shaft 62 of the take-up wheel 36. The shaft 62 is also journalled in the bracket 56. When the output shaft 52 of the clutch is rotated the take-up wheel 36 rotates as a result of the interengagement of the gear wheels 58 and 60. Furthermore the gear wheel 60, shaft 62 and take-up wheel 36 are urged to move transversely to their common axis. The fixed bracket 56 constrains them to move on an arc of a circle centred on the axis of the output shaft 52 of the clutch, the bracket being free to move on this arc.

When the motor is operated the pulley wheels of both take-up mechanisms rotate in opposite directions. Both take-up wheels 36 are thereby rotated and the take-up wheel downstream of the capstan 8 swings from its retracted position to a spool-engaging position. The other take-up wheel is urged in the opposite direction but preferably is restrained against moving by an obstruction (not shown).

The cassette 12 used with the player of Figs. 1 to 3 will now briefly be described by way of example with reference to Fig. 4.

The cassette comprises mating housing parts 64 and 66 which retain tape spools 68 and 70. Each housing has a depressed opening 71 to allow a take-up wheel to engage a rim of a spool.

The tape pathway between the spools leads past the pinch wheel 10, on either side of which are disposed felt covered plastics foam pressure pads 72 to support the tape. The pinch wheel 10 is carried by a yoke 74 which is urged by springing towards the tape but which can be moved against the spring force away from the tape. The cassette further includes a spool braking device comprising brake pads 76 to selectively act on each spool.

When the cassette is inserted into the player the brake pads are engaged with the spools and the pinch wheel 10 is held away from the tape and the capstan 8 by means of a linkage assembly 78 coupled to the play button 80 and acting on one side of the yoke 74 against the spring force. When the play button is pressed the linkage assembly 78 moves to allow the pinch wheel 10 to bear against the capstan 8 with the tape in between. A switch coupled to the play button starts the motor.

The correct track for playback may be selected in various ways. For example, the carriage 20 carrying the magnetic heads 22 can be moved up and down by a mechanical lever. Alternatively, multiple track heads may be used. A track change switch (not shown) is used to select the correct motor direction for the track selected. This switch is automatically incremented electromechanically at the end of each track and the other track is then played using the other playback head and reversing the direction of the motor.

When the tape is being played the tape is drawn at constant speed past the playback head upstream of the capstan and pinch wheel. Both take-up wheels are rotating but only the downstream take-up wheel swings to engage the rim of the spool taking up the tape. The correct tape take-up tension is provided as a result of the use of the slipping clutch 34.

When the fast-forward button 82 or rewind button 84 is depressed the cassette brake pads are held away from the spools and the pinch-wheel is held away from the capstan.

Switches connected to the buttons increse the motor speed and the speed-change platforms 42 of both take-up mechanisms are shifted about their respective pivots 44 to bring the fast speed sheels 40 into engagement between the pulley wheel and the wheel 46 on the output shaft of the clutch, which is thereby by-passed. Both speed-change platforms are moved when either button is pressed as a result of a co-ordination plate 86 coupled to both buttons and to both speed change platforms. Parts 88 projecting from the co-ordination plate also act on the yoke 74 to effect the aforementioned movement of the pinch wheel.

The appropriate take-up wheel 36 is caused to swing into engagement with the adjacent tape spool rim when the appropriate button is pressed and the other take-up wheel rotates but is urged away from its tape spool. A switch (not shown) actuated by the rewind lever reverses the direction of the motor whatever its direction is so that pressing the rewind button always causes the tape to rewind. In contrast pressing the fast forward button always causes the tape to advance in the same direction as it was previously playing.

When the rewind or fast foward button is released the brake pads 76 immediately engage the spools 68 and 70.

Claims (10)

1. A tape player for playing a magnetic tape in both directions without removing the tape from the player, comprising a reversible drive motor rotating a capstan upon which a tape pinch wheel bears when the tape is played, a carriage carrying two tape playback heads, the carriage being pivotable about a pivot axis substantially parallel to the axis of rotation of the capstan, means responsive to the direction in which the motor rotates the capstan for swinging the carriage about its pivot axis, the arrangement being such that the playback head upstream of the capstan is moved into a tape reading position, and first and second tape take-up drives responsive to the direction in which the motor rotates the capstan whereby a tape spool downstream of the capstan is rotated so that the tape winds onto it.

2. A player according to claim 1 wherein each tape take-up drive comprises a tape takeup wheel engageable with a respective tape spool, only the take-up wheel downstream of the capstan being moved to a position in which it engages its tape spool.

3. A player according to claim 2 wherein each take-up drive further comprises a first gear wheel rotated by the motor on a shaft restrained from movement transverse to its axis, a second gear wheel driven by the first gear wheel and disposed on a shaft on which the take-up wheel is disposed, wherein the respective shafts of the gear wheels are jour nalled in a bracket which is free to turn about the axis of the first gear wheel, whereby rotation of the first gear wheel causes the take-up wheel to rotate and urges it to move transversely to its axis on the arc of a circle centred on the axis of the first gear wheel.

4. A player according to claim 3, including means to transmit drive from the capstan to the take-up wheels downstream of the capstan.

5. A player according to claim 2, 3 or 4, wherein both take-up wheels are rotated when the capstan is rotated.

6. A player according to any of claims 2 to 5, having a fast speed mode in which the pinch wheel is held away from the capstan, each take-up drive comprising an input wheel receiving drive from the motor, and a play wheel and a fast speed wheel alternatively operable to transmit drive from the input wheel to the take-up wheel.

7. A player according to any preceding claim wherein the means for swinging the carriage about its axis comprises a slipping clutch having a rotating member which rotates the capstan and a part engaged with the carriage and movable with the rotating member between positions which correspond to the two extreme positions of the carriage.

8. A player according to claim 7 wherein the two extreme positions of the carriage are determined by the abutment of a projection carried by the said part with fixed stops.

9. A player according to any preceding claim including means for selecting the direction of play of the tape and means operating at the end of each track of the tape for automatically reversing the direction of play.

10. A tape player substantially as hereinbefore described with reference to the accompanying drawings.