JPH0429138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an auto-reverse device for a tape recorder that detects when a reel shaft has stopped and switches between left and right pinch rollers.

[Technical background of the invention]

Conventional auto-reverse devices for tape recorders have either electrically detected the end of the tape and operated an electromagnetic plunger to switch the left and right pinch rollers, or mechanically detected the tension at the end of the tape. There are known devices in which the pinch rollers are switched using the rotational force of a flywheel or the like.

[Problems with background technology]

A device that electrically detects the end of a tape is equipped with an electromagnetic plunger, which results in a complicated structure and is disadvantageous in terms of miniaturization.

In addition, devices that utilize the rotational force of the flywheel generally have a pin set up on a part of the flywheel, and this pin is used to tighten the pinch roller switching mechanism, which may impede the balance of the flywheel and also Sometimes, the tape tension becomes temporarily strong, and this may be detected and cause a malfunction.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to provide a tape that does not require accessory parts such as an electromagnetic plunger, is easy to downsize, and is not likely to disturb the balance of the flywheel or cause malfunction. An object of the present invention is to provide an auto-reverse device for a recorder.

[Summary of the invention]

The auto-reverse device for a tape recorder according to the present invention includes a rotation transmitting body, a cam follower, and a pressing auxiliary member symmetrically, the rotation transmitting body is provided with an eccentric circular cam surface and a pressing protrusion, and the reel shaft is provided with a pressing protrusion. A biasing portion is provided to transmit the rotation of the capstan shaft to the reel shaft via the rotation transmitting body and further via the friction mechanism. While the reel shaft is rotating, the pressing biasing section biases the cam follower to cause the contact section provided on a part of the cam follower to slide into contact with the cam surface, but when the reel shaft is stopped, When the biasing force of the pressing biasing part disappears and the abutting part comes to stay at a position away from the cam surface, the pressing protrusion hits the abutting part and the rotation transmitting body moves to the non-engaging position with respect to the reel shaft. do. The pinch roller switching mechanism operates in response to the operation of the rotation transmitting body. Further, when the rotation transmitting body moves to the disengaged position, the presser auxiliary member is moved by the rotation transmitter or the member supporting it, and this presser auxiliary member is applied to the cam follower instead of the pressing biasing portion. Apply force to make the contact part of the cam follower slide into contact with the cam surface.

That is, if the contact portion of the cam follower continues to be separated from the cam surface, the pressing protrusion will come into contact with the contact portion, the rotation transmitting body will be dislocated, and the pinch roller switching mechanism will operate.

With this configuration, the pinch roller switching mechanism does not operate as long as the reel shaft is rotating, and the mechanism operates when the reel shaft stops, eliminating the need for accessory parts such as electromagnetic plungers, resulting in a smaller size. is easy to measure.

Furthermore, there is no risk of disturbing the rotational balance of the flywheel or causing malfunctions during startup or the like.

[Embodiment of the Invention] The figure shows an embodiment of the present invention, and FIG. 1 shows a state in which the right reel shaft 1a is rotating,
FIG. 4 shows a state in which the left reel shaft 1b is rotating. Further, FIGS. 2 and 3 show the process in the middle of changing from the state shown in FIG. 1 to the state shown in FIG. 4.

First of all, if we pay attention to FIG.
a, 4b and the reel shafts 1a, 1b are arranged symmetrically. capstan shaft 3a,
Small gears 5a, 5b and flywheels 6a, 6b are respectively attached to the pinion 3b, and rotary plates 7a, 7b are further provided to be rotatable about the respective capstan shafts 3a, 3b. Each rotating plate 7a,
At one end of 7b are large and small gears 8a, 8b; 9.
The rotation transmission body consisting of a and 9b is connected to the shafts 10a and 10
b, and these shafts 10a, 10
Eccentric circular cam surfaces 11a, 11b are formed around b, and pressing protrusions 12a, 12b are formed at the maximum radius within each eccentric circular cam surface 1a, 1b.
0a and 10b are continuously provided in a protruding manner. The other end of each rotating plate 7a, 7b is a bent piece 13a, 13.
It becomes b.

The pinch rollers 4a, 4b have shafts 14a, 1
It is supported by supports 15a and 15b which are rotatable about 4b, and can move toward and away from the capstan shaft 3a. Further, each of the supports 15a, 15b is also provided with bent pieces 16a, 16b.

In the figure, reference numeral 17 denotes a switching plate that is slidable in the left-right direction, and this switching plate 17 includes the rotating plates 7a, 7b.
The protrusion 18 is sandwiched between the bent pieces 13a and 13b.
a, 18b; 19a, 19b are provided, and furthermore, bent pieces 16a,
Openings 20a and 20b are provided into which 16b is inserted. Note that inclined edges 21a and 21b are provided in a part of each opening 20a and 20b, and when the switching plate 17 moves to the right, the left inclined edge 21b is moved to the left support as shown in FIG. 15b bent piece 1
6b and pull the left pinch roller 4b away from the capstan shaft 3b, and when the switching plate 17 moves to the left, the right inclined edge 21a as shown in FIG.
is slid onto the bent piece 16a of the right support 15a, and the right pinch roller 4a is attached to the capstan shaft 3.
Pull away from a. However, each support body 15a, 15b is connected to each pinch roller 4 by a spring (not shown).
a, 4b are biased in a direction to press them against the capstan shafts 3a, 3b.

Further, an articulated plate 25 is provided near one end of the switching plate 17 and is movable articulately between a pair of stopper pins 23 and 24 by a deployment spring 22. These articulated plates 25 and expansion springs 22 constitute a pinch roller switching mechanism together with the switching plate 17. For example, when the switching plate 17 moves to the left and the articulated plate 25 rotates to a position exceeding the neutral point, This time, the reversing force of the articulation plate 25 moves the switching plate 17 to the left, thereby causing the right pinch roller 4a to be separated from the capstan shaft 3a.

A large and small integrated gear 8 constituting the rotation transmitting body
a, 8b; Among 9a, 9b, the larger diameter gear 8a,
8b meshes with small gears 5a, 5b which are integrated with the capstan shafts 3a, 3b, and small diameter gears 9a, 9.
b is configured to selectively mesh with large gears 26a and 26b provided coaxially with the reel shafts 1a and 1b. In addition, these gears 9a, 26a
The meshing of the gears 9b and 26b, or the meshing of the gears 9b and 26b, is controlled by the rotation of the rotating plates 7a and 7b. tension spring 27 in the direction of
a, 27b. However, the rotation of the rotation plates 7a and 7b is controlled by the left and right movement of the switching plate 17, and when one gear (for example, the right gear 9a) is meshed with the gear 26a, the other gear 9b is in mesh with the gear 26a. is associated away from gear 26b.

Rotating members 28a, 28b that rotate together with the reel shafts 1a, 1b are attached to a shaft common to the reel shafts 1a, 1b, and pin-shaped pressing biasing parts 29a, 29b are fixed to the rotating members 28a, 28b. There is.
Note that the reel shafts 1a, 1b and the rotating member 28
a, 28b and the large gears 26a, 26b are interposed with a friction mechanism (not shown), so that even if the rotation of the reel shaft 1a is stopped, the large gear 26a can be rotated. in this case,
This will cause slippage in the friction mechanism.

In the figure, 30 is a fixed plate, and this fixed plate 30 includes cam followers 31a, 31b and a presser auxiliary member 32.
a and 32b are rotatably supported.

The cam followers 31a, 31b have abutting portions 33a, 33b at the farthest portions from the fulcrum position, pressure receiving portions 34a, 34b located on the rotational orbits of the pressing and urging portions 29a, 29b, and an elastic portion near the fulcrum position. It has pieces 35a and 35b.

Further, the presser auxiliary member 32a is approximately L-shaped, and one side 36a, 36b is connected to the shafts 10a, 10b.
and the other sides 37a, 37
b is the elastic piece 35 of the cam follower 31a, 31b.
a and 35b.

Next, the action will be explained.

In FIG. 1, the right pinch roller 4a is in pressure contact with the capstan shaft 3a, and the rotation of the capstan shaft 3a in the direction of the arrow is transmitted to the right reel through gears 5a, 8a, 9a, 26a and a friction mechanism (not shown). A state in which the signal is transmitted to the shaft 1a is shown.

At this time, the rotational force of the reel shaft 1a is transmitted to the cam follower 31a via the pressing urging portion 29a,
The contact portion 33a of the cam follower 31a is connected to the cam surface 11.
Slide into contact with a. As long as the contact portion 33a is in sliding contact with the cam surface 11a in this manner, the contact portion 33a and the pressing protrusion 12a will not come into contact with each other.

It is now assumed that playback or recording is being performed while a tape is being wound around the right reel shaft 1a. At this time, the left reel shaft 1b is on the payout side, so the pressing urging portion 29b does not press the pressure receiving portion 34b of the cam follower 31b. However, in this state, the left rotation transmitting body (gears 8b, 9b) has moved away from the large gear 26b and has moved to a non-engaging position with respect to the reel shaft 1b, and the presser auxiliary member 32 is moved by the shaft 10b.
One side of b is pressed. Therefore, the other side of the presser auxiliary member 32b is the elastic piece 35 of the cam follower 31b.
b is now pressed, and the presser auxiliary member 32b instead of the pressing biasing portion 39b holds the contact portion 33b of the cam follower 31 in sliding contact with the cam surface 11b.

Next, when the tape is completely wound onto the right reel, a slip occurs in the friction mechanism inserted between the large gear 26a and the reel shaft 1a.
The reel shaft 1a stops. Therefore, the cam surface 11a
The contact portion 33a that is in sliding contact with the shaft 10a separates from the cam surface 11a when it is closest to the shaft 10a, and the pressing protrusion 12a comes into contact with the contact portion 33a as shown in FIG. When this happens, the cam follower 31
Since the fulcrum of a does not move, the rotation transmitting body, that is, the rotating plate 7a rotates against the spring 27a, separating the gear 9a from the large gear 26a. As a result, the transmission of rotation to the large gear 26a is cut off.

On the other hand, due to the rotation of the rotating plate 7a, this rotating plate 7
The bent piece 13a of a presses the protrusion 19a of the switching plate 17 from the right side as shown in FIG. 3, and moves the switching plate 17 to the left. Along with this, the articulating plate 25 rotates clockwise while accumulating the deployment spring 22, and when the neutral point of the spring 22 is exceeded, the elasticity of the spring 22 acts in the direction of rotating the articulating plate 25. Then, the switching plate 17 is rapidly moved to the left.

At this time, the left inclined edge 21b of the switching plate 17 is released from the support 15b as shown in FIG.
a is rotated in the opposite direction, the left pinch roller 4b comes into pressure contact with the capstan shaft 3b, and the right pinch roller 4a is separated from the capstan shaft 3a.

Further, the left rotating plate 7b is pulled by the spring 27b and rotates clockwise, thereby causing the small gear 9b of the rotation transmission body to mesh with the large gear 26b.

Therefore, as shown in FIG. 4, the configuration is opposite to that in FIG. 1, and the left reel shaft 1b rotates in the winding direction, and the tape is wound on the left reel while being played or recorded. It becomes like this.

〔Effect of the invention〕

As described above, according to the auto-reverse device for a tape recorder according to the present invention, accessory parts such as an electromagnetic plunger are not required, and therefore the configuration is easy to downsize. Furthermore, the balance of the flywheel is not disturbed, and since the pinch roller switching mechanism is actuated by detecting the stoppage of the reel shaft, malfunctions do not occur even if the tape tension temporarily increases during startup.

[Brief explanation of drawings]

1 to 4 are schematic configuration diagrams of an auto-reverse device according to an embodiment of the present invention. 1a, 1b...Reel shaft, 2...Magnetic head,
3a, 3b... Capstan shaft, 4a, 4b...
Pinch roller, 8a, 8b...Large gear, 9a, 9
b... Small gear, 11a, 11b... Eccentric circular cam surface, 12a, 12b... Pressing protrusion, 17... Switching plate (pinch roller switching mechanism), 29a, 29b...
...Press biasing portion, 31a, 31b...Cam follower, 32a, 32b...Press auxiliary member, 33a,
33b...Abutment part.

Claims (1)

[Claims] 1 Arrange the capstan shaft, pinch roller and reel shaft symmetrically on the left and right sides of the magnetic head,
The capstan shafts on both sides and one of the reel shafts are constantly driven to rotate, and the pinch roller on the same side as the rotating reel shaft is pressed against the corresponding capstan shaft to move the magnetic tape in one direction. In an auto-reverse device for a tape recorder that automatically switches the running direction of a magnetic tape when the magnetic tape is wound to the end,
The pressing force is provided at an eccentric position on each of the reel shafts, and the reel shaft is symmetrical in that it constantly rotates under the rotational force of each capstan shaft and transmits the rotational force to the corresponding reel shaft via a friction mechanism. A rotation transmitting body, an eccentric circular cam surface and a pressing protrusion provided around the rotation axis of each rotation transmitting body, and a contact portion in a part, and while the reel shaft is rotating, the above-mentioned By forcing each contact portion to slide into contact with each of the cam surfaces under pressure from the pressing biasing portion, the contact portions are released from the pressing protrusion, the reel shaft stops, and the biasing force of the pressing biasing portion disappears. a symmetrical cam follower that brings the pressing protrusion into contact with the abutting portion and moves the rotation transmitting body to a non-engaging position with respect to the reel shaft when the abutting portion remains at a position away from the cam surface; When the transmission body moves to a non-engaging position with respect to the reel shaft, it is pushed by this rotation transmission body or a member supporting it, and applies a biasing force to the cam follower instead of the pressing biasing unit, causing the abutting part of the cam follower to contact the cam surface. It is equipped with a presser auxiliary member that slides into contact, and a pinch roller switching mechanism that switches the left and right pinch rollers toward and away from the capstan shaft in response to the movement when the rotation transmitting body moves to a non-engaging position. An auto-reverse device for a tape recorder, which is characterized by: