JPH01248346A - Tape termination detector for cassette tape recorder - Google Patents

Abstract

PURPOSE:To thin and miniaturize a device by mounting first and second rotors on a first shaft concentrically and a third rotor on a second shaft rotatably freely, respectively, and furthermore, mounting a frictional member on the third rotor in such a way that it can be turned freely via a clutch mechanism. CONSTITUTION:Since a take-up gear spring 42 and a spring 47 comprising the clutch mechanism are provided on the shafts of a take-up gear shaft 31 and a friction gear shaft 44, respectively, the diameter of the take-up gear spring 42 can be reduced. Also, a take-up gear shaft 31 on which a take-up gear boss 43, a take-up gear 36, and a take-up gear 41 are mounted rotatably freely and a friction gear shaft 44 on which a friction gear 45 and a frictional plate 48 are mounted rotatably freely are provided separately. Therefore, it is possible to reduce size in a thickness direction or a width direction. In such a way, the device can be thinned and miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a tape end detection device for a cassette tape recorder.

(Prior Art) In recent years, portable cassette tape recorder devices (hereinafter simply referred to as tape recorders) that are capable of recording and reproducing information using magnetic tape have become widespread.

Such tape recorders are equipped with a device that detects the end of the tape in order to operate an automatic stop mechanism, an auto-reverse mechanism, and the like.

FIGS. 3 and 4 show such a tape end detection device.

As shown in these figures, a take-up gear shaft 2 is attached to a chassis 1. A take-up gear boss 4 having a flange 3 is rotatably attached to the take-up gear shaft 2. The take-up gear boss 4 is prevented from detaching the take-up gear shaft 2 in the axial direction by a retaining ring 5.

The inner circumferential surface of a cylindrical portion 9 of a take-up gear 8 having an engaging portion 6 and an eccentric cam 7 is in contact with the take-up gear boss 4, and the flange 3 of the take-up gear boss 4 is in contact with a take-up gear 10. The inner walls of the The outer circumferential surface of the cylindrical portion 9 of the take-up gear 8 is in contact with the inner circumferential surface of a hole 14 of a take-up gear wheel 13 having a felt 11 and a flange 12. The felt 11 of the take-up gear wheel 13 is pressed against the surface of the take-up gear 8 by a take-up gear spring 15 that constitutes a clutch mechanism interposed between the take-up gear wheel 13 and the flange 3 of the take-up gear boss 4. It is being

A friction plate 17 having an engagement hole 6 is pressed against the surface of the flange 12 of the winding gear wheel 13 by a spring 18 constituting a clutch mechanism.

Further, a swing lever shaft 19 is attached to the chassis 1. The swing lever shaft 19 has an engagement hole 16 in the friction plate 17.
A swing lever 22 is rotatably mounted, having a protrusion 20 inserted into the eccentric cam 7 and a protrusion 21 abutting the circumferential surface of the eccentric cam 7. The swing lever 22 is prevented from disengaging in the axial direction of the swing lever shaft 9 by a retaining ring 23.

In the figure, 24 is a reel stand to which rotational force is applied by the take-up gear 10, 25 is a release lever for unlocking (automatic stop mechanism) and reverse switching (auto reverse mechanism),
26 is a motor drive gear that transmits the driving force of the motor.

The tape end detection device having such a configuration performs the following operations.

First, when the tape runs, when the motor drive gear 26 rotates in the direction of arrow a due to the driving force of the motor, the take-up gear 8 that meshes with this motor drive gear 26 rotates in the direction of the arrow. Next, the take-up gear wheel 13 rotates in the direction of the arrow due to the frictional force of the felt 11 which is biased against the surface of the take-up gear 8 by the take-up gear spring 15, and the take-up gear spring is pushed through the flange 3 of the take-up gear boss 4. 15 rotates in the same direction. Thereafter, the reel stand 24 that meshes with the take-up gear 10 rotates in the direction of arrow C.

On the other hand, the operation of the swing lever 22 is as follows.

First, the protrusion 2o of the swing lever 22 is connected to the take-up gear wheel 1.
The friction plate 17 is engaged with the engagement hole 16 of the friction plate 17, which attempts to rotate in the direction of the arrow due to the frictional force generated between the friction plate 17 and the
The protrusion 21 biased toward point e moves between point d and point e while always in contact with the circumferential surface of eccentric cam 7. At this time, as the eccentric cam 7 of the take-up gear 8 rotates, the protrusion 21 of the swing lever 22 shifts from point d to point e in the figure. At this time, the end of the swing lever 22 on the release lever 25 side repeats rotation in the directions of arrows g and h using the swing lever shaft 19 as a fulcrum without contacting the release lever 25.

Through this series of operations, the tape continues to run, and when the tape ends, the reel stand 24 stops rotating. Along with this, the take-up gear 1o and the take-up gear wheel 1
Since the rotation of the friction plate 3 stops, the force of the friction plate 17 trying to rotate in the direction of the arrow disappears.

On the other hand, the take-up gear 8, which receives the driving force from the motor via the motor drive gear 26, continues to rotate in the direction indicated by the arrow, against the frictional force of the felt 1 of the take-up gear wheel 13. As a result, the swing lever 2 loses its return force due to the friction plate 17.
The second protrusion 21 is pushed to point e by the eccentric cam 7.

Thereafter, the protrusion 21 of the swinging lever 22 engages with the engagement part 6 of the winding gear 8, and is pushed by the inclined surface of the engagement part 6 from point e to point f further outside. As a result, the end of the swing lever 22 presses the release lever 25 in the direction of the arrow i, so that the release lever 25 rotates in the direction of the arrow i with the shaft 26 as a fulcrum. As a result, an automatic stop mechanism, an auto reverse mechanism, etc. that are linked to the movement of the release lever 25 start operating.

(Problems to be Solved by the Invention) By the way, in the conventional tape end detection device described above, the winding gear 8, the winding gear 10, the friction plate 17, the winding gear spring 15, and the winding gear spring 15 are coaxially disposed on the winding gear shaft 2. 18 are arranged. Further, since the winding gear spring 15 is arranged within the diameter of the spring 18, the diameter of the spring 18 is increased.

As a result, the dimensions of the tape end detection device in the thickness direction and the width direction become large, which hinders the reduction in thickness and size of the Cheaple=6-Korg.

The present invention was made under these circumstances, and an object of the present invention is to provide a tape end detection device for a cassette tape recorder that can be made thinner and smaller.

[Structure of the Invention (Means for Solving the Problems) In order to achieve the above object, the tape end detection device of the cassette tape recorder of the present invention is rotatably attached to a first shaft and interlocked with tape running. a second rotating body that has an eccentric cam and an engaging portion and is rotatably attached coaxially to the first shaft and rotates independently of tape running; A third rotating body connected to the rotating body and rotatably attached to the second shaft; a friction member rotatably attached to the third rotating body via a clutch mechanism; It has an engaging portion that follows the eccentric cam of the second rotary body in response to biasing force and that is engaged with the engaging portion when the rotational movement of the third rotary body stops due to tape running being stopped. A swinging member is provided.

(Function) In the tape end detection device for a cassette tape recorder of the present invention, the first rotating body and the second rotating body are rotatably attached coaxially to the first shaft, and the third rotating body is rotatably attached to the second shaft. Space in the thickness direction and width direction can be effectively saved by attaching a rotary body rotatably and making the friction member rotatable via a clutch mechanism on this third rotary body to detect the end of the tape. can be used.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

1 and 2 show a tape end detection device (hereinafter simply referred to as tape end detection device) of a cassette tape recorder.

As shown in these figures, a take-up gear shaft 31 is attached to the chassis 30. This winding gear shaft 31 has
A take-up gear boss 34, which has a gear 32 and whose take-up gear shaft 31 is prevented from being removed in the axial direction by a plate 33, is rotatably mounted.

The inner peripheral surface of a cylindrical portion 37 of a take-up gear 36 having a flange 35 is in contact with the take-up gear boss 34 . Winding gear 3
The inner circumferential surface of a winding gear 41 having a felt 38, three engaging portions, and an eccentric cam 40 is in contact with the outer circumferential surface of the cylindrical portion 37 of No. 6. A take-up gear spring 42 that constitutes a clutch mechanism is interposed between the take-up gear 41 and the take-up gear boss 34.

A friction gear shaft 44 is attached to the plate 43. A friction gear 45 that meshes with the gear 32 of the take-up gear boss 34 is rotatably attached to the friction gear shaft 44 . A friction plate 48 having an engagement hole 46 and biased by a spring 47 constituting a clutch mechanism is in contact with the friction gear 45 . Further, a shaft 50 is attached between the plate 43 and the sub-chassis 49.

A swing lever 53 is rotatably attached to the shaft 50 and has a protrusion 51 that is inserted into the engagement hole 46 of the friction plate 48 and a protrusion 52 that comes into contact with the circumferential surface of the cam 40 .

In the figure, 54 is a reel stand to which rotational force is applied by the gear 32 of the take-up gear boss 34, 55 is a release lever, and 56 is a motor drive gear that transmits the driving force of the motor.

The tape end detection device having such a configuration performs the following operations.

First, when the tape runs, when the motor drive gear 56 rotates in the direction of arrow A due to the driving force of the motor, the take-up gear 41 meshing with this motor drive gear 56 rotates in the direction of arrow B. Next, the take-up gear 36 rotates in the direction of arrow B due to the frictional force of the felt 38, and at the same time the take-up gear boss 3
4 also rotates in the same direction. Thereafter, the reel stand 54 that meshes with the gear 32 of the take-up gear boss 34 rotates in the direction of arrow C.

On the other hand, the operation of the swing lever 5B is as follows.

-Co-〇- First, as the friction gear 45 that meshes with the protrusion 51 of the swing lever 53 or the gear 32 of the take-up gear boss 34 rotates in the direction of the arrow, the friction plate tries to rotate in the same direction due to the frictional force. Since it is engaged with the engagement hole 46 of 48, the protrusion 5
2 is always in contact with the circumferential surface of the eccentric cam 40 between points E and F.
Move between points. At this time, as the eccentric cam 40 of the take-up gear 41 rotates, the protrusion 52 of the swing lever 53 deviates from point E to point F in the figure. Also at this time, the release lever 5
The end of the swinging lever 53 on the 5 side repeatedly rotates in the directions of the arrows H and 3 using the shaft 50 as a fulcrum without contacting the release lever 55.

Through this series of operations, the tape continues to run, and when the tape reaches its end, the rotation of the reel stand 54 is stopped due to the tension of the tape. Along with this, the winding gear boss 3
4 and the winding gear 36 stop rotating, the friction plate 4
The force that tries to rotate in the direction of the arrow 8 disappears.

On the other hand, the take-up gear 41, which receives the driving force from the motor via the motor drive gear 56, resists the frictional force generated between the felt 38 of the take-up gear 11-41 and the flange 35 of the take-up gear 36. and continue rotating in the direction of arrow B.

As a result, the protrusion 52 of the swing lever 53, which has lost the return force exerted by the friction plate 48, is pushed to point E by the eccentric cam 40.

Thereafter, the protrusion 52 of the swing lever 53 engages with the engagement part 39 of the take-up gear 41, and is further pushed outward to point G by the inclined surfaces of the three engagement parts. Next, the release lever 55 is moved to the shaft 56.
Rotate in the direction of arrow J using as a fulcrum. As a result, an automatic stop mechanism, an auto reverse mechanism, etc. that are linked to the movement of the release lever 55 start operating.

As described above, in this embodiment, the winding gear spring 42 and the spring 47 constituting the clutch mechanism are connected to the winding gear shaft 3, respectively.
1 and on the axis of the friction gear shaft 44,
The diameter of the winding gear spring 42 can be made smaller. Furthermore, a take-up gear shaft 31 to which the take-up gear boss 34, the take-up gear 36, and the take-up gear 41 are rotatably attached, and a friction gear shaft 44 to which the friction gear 45 and the friction plate 48 are rotatably attached are separately provided. Therefore, the dimension of the tape end detection device in the thickness direction can be reduced.

Thereby, the dimensions of the tape end detection device in the thickness direction and the width direction can be reduced, so that the space in the thickness direction and the width direction can be used effectively.

[Effects of the Invention] As explained above, the tape end detection device for a cassette tape recorder of the present invention can effectively use the space in the thickness direction and the width direction, thereby achieving reduction in thickness and size. be able to.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a tape end detection device showing an embodiment of the present invention, FIG. 2 is a sectional view showing the main parts of FIG. 1, and FIG. 3 is a plan view of a conventional tape end detection device. FIG. 4 is a sectional view showing the main part of FIG. 3. 30... Yarn, 31... Take-up gear shaft, 34...
・Take-up gear boss, 36・Take-up gear, 38...Felt,
39... Engaging portion, 40... Eccentric cam, 41... Winding gear, 42... Winding gear spring, 44... Friction gear shaft, 45... Friction gear, 46... Engagement Matching hole, 47... Spring, 48... Friction plate, 51.52
... Projection, 53... Swing lever. Applicant Toshiba Corporation Toshiba Audio/Video Engineering Co., Ltd. Agent Patent Attorney Sasa Suyama −

Claims (1)

[Claims] a first rotating body that is rotatably attached to the first shaft and rotates in conjunction with tape running; a first rotating body that is coaxially rotatably attached to the first shaft and has an eccentric cam and an engaging portion; a second rotating body that rotates independently of traveling; and a third rotating body that is connected to the first rotating body and rotatably attached to a second shaft.
a rotating body, a friction member rotatably attached to the third rotating body via a clutch mechanism, and the friction member receives a biasing force and moves to follow the eccentric cam of the second rotating body. A cassette tape comprising: a swinging member having an engaging portion that is engaged with the engaging portion when the rotational operation of the third rotating body is stopped due to stopping of tape running; Recorder tape end detection device.