GB2239550A

GB2239550A - Tape recorder reel driving system

Info

Publication number: GB2239550A
Application number: GB9020595A
Authority: GB
Inventors: Bongju Kim
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 1989-12-31
Filing date: 1990-09-21
Publication date: 1991-07-03
Also published as: DE4021601A1; FR2656625A1; GB9020595D0; JPH03212840A; KR910013131A; KR920008480B1

Abstract

A reel driving system for a magnetic tape recorder is disclosed. A power transmitting device 4 driven by means of a Capstan motor 2 is installed between a supply reel disc 1 and a take up reel disc 1'. An idler 5 engaged with the power transmitting device 4 is pivoted by a lateral moving means 7, 8 driven by another power source which is distinct from the capstan motor 2. A typical motor for loading a cassette and tape can be available as the power source of the lateral moving means. Loosening of the tape during the shifting of the driving mode may be prevented and a quick response for the shift of driving mode may be accomplished. <IMAGE>

Description

TAPE RECORDER REEL DRIVEG SYSTEM The present invention relates to a tape

recorder system, and particularly to a reel driving system in which an idler is provided to selectively drive one of two reel discs where a tape supply reel and a tape take-up reel are respectively mounted, and a capstan motor for driving the tape at a constant speed is used as the driving source for the reel discs.

In a conventional video tape recorder, as shown in Figure 1 of the accompanying diagrammatic drawings, a tape T is supplied and wound by means of a supply reel SR and a take-up reel TR, and the tape T is also driven at a constant speed in close contact with capstan shaft CS of a capstan motor CM which is precisely driven and controlled.

The supply reel SR and the take-up reel TR are respectively mounted on reel discs RD and RY, and if either one of the reels is driven in a direction to wind the tape T, then the other one is revolved in a direction to unwind the tape T by being pulled by the moving tape T.

The reel disc RD or RD' is selectively driven by an idler ID which is disposed between the reel discs RD and RY. The idler ID revolves in contact at all times with a power transmitting device D which is driven by the capstan motor CM, while the idler ID also performs lateral movements based upon the rotation of the power transmitting device D so as to selectively contact the reel disc RD or RY. In more detail, the idler ID is provided with a lateral moving means so that the idler ID should be able to move leftwardly or rightwardly upon encountering a shifting of the driving mode correspondingly with the moving direction of the tape T. That is, as shown in Figure 2 of the accompanying diagrammatic drawings, a coupling lever L is conventionally installed on both a fixed shaft DS of the power transmitting device D and on a movable shaft IS of the idler ID in such a manner that the idler ID can be moved leftwardly or rightwardly based on the principle that a rotational moment acts on the coupling lever L depending on the rotating direction of the idler ID when it is rotated by the power transmitting device D.

However, in such a conventional system, it is understood that the capstan motor CM has to be driven in order to cause the lateral movements of the idler ID for the shifting of the driving mode. This means that the tape is being transported during the shifting of the driving mode, with the result that tape loosening occurs near the capstan shaft.

Furthermore, in the conventional system, the distance of the lateral movements of the idler is relatively long, and thus the time required for the lateral movements or the shifting time of the driving mode becomes extended as well as causing significant tape loosening. Therefore, existing video tape recorders utilizing such a conventional driving system can produce wild noises on a television screen because of the loosening of the tape during the shifting of the driving mode and can not accomplish quick response for successive changes of driving mode.

Preferred embodiments of the present invention aim to overcome or mitigate the above described disadvantages of the conventional system.

It is an object of such embodiments to provide a novel reel driving system in which no loosening of the tape occurs during the shifting of the driving mode.

It is another object to provide an improved reel driving system which can reduce the shifting time of a driving mode.

According to a first aspect of the present invention, there is provided a reel driving system for a tape recorder, the system comprising:

1 Z a capstan motor for driving the tape at a constant speed; first and second reel discs for mounting a tape supply reel and a tape take-up reel; an idler arranged to be driven by said capstan motor and being mounted for movement between a first position in which it transfers drive between said capstan motor and said first reel disc for tape transport in one direction, and a second position in which it transfers drive between said capstan motor and said second reel disc for tape transport in an opposite direction; and a moving means for moving said idler between said positions in response to a power source which is operative independently of the capstan motor.

Preferably, the reel driving system includes a power transmitting device arranged to transmit power between the capstan motor and said idler.

Preferably, said power transmitting device comprises a drive wheel arranged to be driven by said capstan motor, said idler is in driven contact with said drive wheel, and said idler is mounted for pivotal movement about said drive wheel, between said first and second positions.

Preferably, said moving means comprises an actuation bar having a cam surface and being longitudinally and reciprocally moveable in a predetermined stroke by said power source, and a member having a cam follower which engages said cam surface and has an engagement portion which engages the idler to move it between said first and second positions.

Preferably, the reel driving system includes at least one respective intermediate power transmitting device between said idler and each of said reel discs.

At least two respective intermediate power transmitting devices may be provided between said idler and each of said reel discs.

The invention extends to a tape recorder provided with a reel driving system as above in accordance with the first aspect of the invention. Such a tape recorder may be a video tape recorder.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to Figures 3 and 4 of the accompanying diagrammatic drawings, which are schematic plan views of one example of a reel driving system embodying the present invention, in alternative modes.

In Figures 3 and 4, a power transmitting device 4 is installed between two reel discs 1 and 1' and is driven by a capstan motor 2 through a belt 3. An idler 5 is driven in contact with the power transmitting device 4. A fixed shaft 4a of the power transmitting device 4 and a movable shaft 5a of the idler 5 are connected by means of a coupling lever 6 which can be pivoted around the fixed shaft 4a.

An actuation bar member 7 which can be moved leftwardly or rightwardly by a separate power source (not shown) serves as a member of a lateral moving means for the idler, and is aligned along the direction that connects the shafts of the two reel discs 1 and F. At the upper portion of the actuation bar 7, there is integrally formed a 2-position-shiftable cam 7a. One end of an interlocking member 8 is provided with an elastic arm 8a which is capable of sliding along the upper surface of the cam 7a, while the other end of the interlocking member 8 is provided with an elongate slot 8b, the interlocking member 8 being pivotable around a fixed supporting pin 8c.

In order to reduce the distance of the lateral niovements, of the idler 5, there are installed first and second intermediate power transmitting devices 9 and 9' and third and fourth intermediate power transmitting devices 10 and 10'. The first and second power transmitting devices 9 and 9' are respectively placed in contact with the two reel discs 1 and 1' at all times, while the third and fourth power transmitting devices 10 and 10' are respectively placed in contact with the first and second power transmitting devices 9 and 9' at all times, and are selectively in contact with the idler 5.

a In the above described system, the actuation bar member 7 can comprise a mode shifting lever of a type which is currently used to accomplish tape transferring and stopping functions in video tape recorders. This mode shifting lever is typically interlocked to a cassette/tape loading motor, a loading cam and a cam lever, without using the power of the capstan motor 2.

An example of operation of the illustrated reel driving system will now be described.

During mode shifting, for example, when the drive is shifted from a normal playback mode (or slow playback mode) to a reverse playback mode (or slow reverse playback mode), the capstan motor 2 is stopped temporarily, and the actuation bar 7 is moved leftwardly or rightwardly by a loading motor (not shown), associated loading cam and cam lever.

Then, the interlocking member 8 which is equipped with the elastic arm 8a interlocked with cam 7a of actuation bar 7 is pivoted so that the idler 5 will be laterally moved. The combination of actuation bar 7 and interlocking member 8 as illustrated enables the shifting of the driving mode to be faster than that of the conventional mechanism as depicted in Figures 1 and 2. Upon completion of the lateral movement, the capstan motor 2 is driven in the required direction, so that reel disc 1 or 1' will be selectively driven, thereby placing the tape in motion.

Figure 3 depicts the case where driving is in a forward mode. Here, the elastic arm 8a of the interlocking member 8 is free from the cam 7a, and the idler is contacted with the fourth intermediate power transmitting device 10'. Under this condition, if the actuation bar member 7 is moved rightwardly by the loading motor (not shown) which is operative independently of capstan motor 2, then the tip of elastic arm 8a is elevated along the sloped surface of cam 7a, and consequently interlocking member 8 moves the idler 5 into contact with the third intermediate power transmitting device 10, as depicted in Figure 4, so that driving is then in a reverse mode.

Upon then moving the actuation bar member 7 back to the left, the cam 7a disengages from the elastic arm 8a, allowing the interlocking member 8 to pivot anti-clockwise, and thereby moving the idler 5 back into contact with the fourth intermediate power transmitting device 10', to re-establish forward mode. In this emobodiment, the interlocking member 8 is biased permanently in an anti- clockwise direction by a resilient biasing means (not shown), so that as the actuation bar 7 is moved to the left at the same time the member 8 pivots anti-clockwise by the above mentioned resilient biasing means 4.

In the illustrated reel driving system as described above, since the driving mode is quickly shifted by moving the idler by a lateral moving means which does not require the power of the capstan motor, the tape loosening phenomenon can be prevented and also quick response for the change of driving mode may be accomplished. Further, owing to the fact that the distance of the lateral movements -2 1 i of the idler between the reel discs is narrowed, the shiftings are carried out during a minimal time period.

The scope of the present invention is not limited to the embodiment described above and illustrated in the drawings, but various modifications and variations will be possible within the technical scope of the present invention as defined in the attached claims.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

CLAMS 1. A reel driving system for a tape recorder, the system comprising:

a capstan motor for driving the tape at a constant speed; first and second reel discs for mounting a tape supply reel and a tape take-up reel; an idler arranged to be driven by said capstan motor and being mounted for movement between a first position in which it transfers drive between said capstan motor and said first reel disc for tape transport in one direction, and a second position in which it transfers drive between said capstan motor and said second reel disc for tape transport in an opposite direction; and a moving means for moving said idler between said positions in response to a power source which is operative independently of the capstan motor.

2. A reel driving system according to claim 1, including a power transmitting 20 device arranged to transmit power between the capstan motor and said idler.

3. A reel driving system according to claim 2, wherein said power transmitting device comprises a drive wheel arranged to be driven by said capstan motor, said idler is in driven contact with said drive wheel, and said idler is mounted for pivotal movement about said drive wheel, between said first and second positions.

4. A reel driving system according to claim 1, 2 or 3, wherein said moving means comprises an actuation bar having a cam surface and being longitudinally and reciprocally moveable in a predetermined stroke by said power source, and a 30 member having a cam follower which engages said cam surface and has an sr engagement portion which engages the idler to move it between said first and second positions.

5. A reel driving system according to claim 1, 2, 3 or 4, including at least one 5 respective intermediate power transmitting device between said idler and each of said reel discs.

6. A reel driving system according to claim 1, 2, 3 or 4, including at least two respective intermediate power transmitting devices between said idler and each of 10 said reel discs.

7. A reel driving system for a tape recorder, the system being substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.

is 8. A tape recorder provided with a reel driving system according to any of the preceding claims.

9. A tape recorder according to claim 8, being a video tape recorder.

Published 1991 at The Patent Office. State House. 66171 High Holbom, L4ondonWC1R41P. Further copies may be obtained frorn Sales Branch. Unit 6. Nine Mile Point. Cwrnfelinfach, Cross Keys, Newport. NPI 7HZ. Printed by Multiplex techniques ltd, St Mary Cray. Kent.