JPS61104454A - Power mechanism of tape recorder - Google Patents

Abstract

PURPOSE:To improve the durability as well as the accuracy of a locking position by providing a stage part having a diameter slightly larger than that of a lock part between the maximum diameter part and said lock part for a cam set to an intermittent gear. CONSTITUTION:When a roller 4a of a power plate 4 gets over the maximum diameter part 3a of a cam 3, the plate 4 starts its resetting action to the left side by the power of a spring 5 with guidance given from a gentle sloping part A. Then the roller 4a moves down along a sudden sloping surface B of the cam 3 and then drops quickly to a stage part C of a small diameter. In this case, the power of the spring 5 is virtaully absorbed by the axial core of the cam 3 since the part C has an arc form concentric with the axial core of the cam 3. At the same time, the plate 4 is stopped temporarily or decelerated greatly at the part C. This produces no revolving power to the cam 3. Then the roller 4a, i.e., the plate 4 is moved at an extremely low speed even after the impact due mostly to the power of the spring 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a power mechanism for a tape recorder. In particular, the shape of the cam is improved to reduce the impact force applied to the locking means of the power plate. , which improves the accuracy of the cam stop position.

[Technical Background of the Invention] There are five modes for tape recorders: stop, play, fast forward, rewind, and program change.
In recent years, tape recorders have become more automated, and each mode can be maintained and switched using the attraction force of an electromagnetic plunger and the driving force of a motor, eliminating the need for manual operation force and simply pressing a switch. Tape recorders that can switch between various modes with extremely simple operations have been put into practical use.

In such an automated tape recorder, various types of power mechanisms have been known for moving each member to a predetermined mode, one of which is the 5th power mechanism.
As shown in the figure, a cam 12 is interlocked with an intermittent gear 11 that intermittently meshes with a drive gear on the motor side, and the cam 12 moves the power plate 13 forward and backward. ! There are devices that move driven members such as head plates and channel change plates. In this type of power mechanism, during a certain mode, the power plate 13 is locked in a position where the intermittent portion 11a of the intermittent gear 11 faces the drive gear 15 using the locking means 14. Even if the motor rotates during execution, the power plate 13 does not move and the driven members are prevented from moving. When moving from this mode to another mode, the locking means 14 is moved using an electromagnetic plunger or other means, the power plate 13 is unlocked, and the intermittent gear 11 is shifted to the drive gear 15.
The power plate 13 is moved to the right side in the figure by the cam 12 of the intermittent gear 11 that is engaged with and rotates, and the driven member that is interlocked with the power plate 3 is moved to a new mode position.

In addition, the power plate 13 is returned in its return direction and is urged by a spring 16, whereby the roller 13a on the plate 13 is pressed against the cam 12, and after the roller 13a has climbed over the maximum diameter portion 12a, , the power plate 13 is returned to its original position by the urging force of the spring 16.

Furthermore, the cam 12 is drawn in by the force of a spring 13 of a power plate 13. That is, when the power plate 13 is locked by the locking means 14 as described above and the intermittent gear 11 comes to a position where the intermittent portion 1 a is opposed to the drive gear 15, the roller 1 of the cam 12
The locking portion 12b with respect to 1a is provided in the middle of the inclined surface before the minimum diameter portion 12a. Then, when a drive signal for the power plate 13 is input, the electromagnetic plunger unlocks the locking means 14 of the power plate 13-, and the power plate 13 is moved in the return direction (drawing direction) by the force of the spring 16. Roller 1 of power plate 13
3a is in the middle of the inclined surface of the cam 12, so the cam 12 is pressed, which causes the cam 12 to rotate, and the intermittent gear 11, which is integrated with the cam 12, rotates and meshes with the drive gear of the motor.
Calling is completed.

[Problems with back song technology] However, the power mechanism of the conventional tape recorder as described above has the following drawbacks.

That is, when the motor operates, the force of the spring 16 applied to the power plate 13 becomes a burden, so in order to reduce this burden, the maximum diameter portion 12a of the cam 12 that pulls the power plate 13 against the spring 16 is used. It is necessary to have a gentle slope, and therefore, its length is required to be long. For this reason, the length after exceeding the maximum diameter portion is relatively shortened, and there is a steeply sloped surface during this period. Therefore, the power plate 13 returns at high speed due to the biasing force of the spring 16, and the biasing force of the spring 16 applied to the power plate 13 is directly applied to the locking means 14 of the power plate 13, but in this case, the maximum Since the fully extended spring 16 instantly contracts, a large impact force is applied to the locking means 14. As a result, the durability of the locking means 14 of the power plate 13 is significantly reduced, posing a serious problem in terms of the performance of the tape recorder.

Furthermore, since the slope from the maximum diameter portion 12a of the cam 12 to the lock portion 12b is in a downward direction with respect to the axis, the rotational force of the cam 12 tends to increase.
2 rotates excessively, it is difficult to accurately stop the roller 13a at the lock portion 12b, and it becomes impossible to lock the power plate 13, which may cause an inconvenience such as the power plate 13 moving again. .

[Object of the Invention] The present invention was proposed in order to eliminate the drawbacks of the prior art as described above, and its purpose is to improve the attachment of the spring applied to the power plate by improving the shape of the cam. To provide a power mechanism for a tape recorder that absorbs force, reduces impact force related to a locking means of a power plate, improves its durability, and improves accuracy of lock position.

[Summary of the Invention] The power mechanism of the tape recorder of the present invention has a structure in which the cam provided in the intermittent gear is provided with a step portion having a diameter slightly larger than the lock portion between the maximum diameter portion and the lock portion. When the roller of the power plate moves from the maximum diameter part to the lock part, the stepped part! By absorbing most of the urging force of the iron splinter, when the power plate is locked to the locking means, the impact force applied to the locking means is reduced.

By configuring this stepped portion to be formed in an arc concentric with the cam or an inclined surface in the opposite direction to the cam, the return spring force received from the roller is received at the axis of the cam.
Since no rotational force is generated on the cam, there is no need to increase the return speed of the power plate, and there is no unnecessary movement on the cam.

There is no inconvenience such as repeating this and making the power plate unstable.

[Embodiment of the Invention] An embodiment of the power mechanism of the tape recorder according to the present invention as described above will be specifically described with reference to FIGS. 1 and 3.

As shown in Fig. 2, the intermittent gear 1 has an intermittent part 1a without gear teeth around it, and rotates clockwise in the figure when it meshes with the drive gear 2 that interlocks with the motor. However, when the drive gear 2 faces the intermittent portion 1a, it does not rotate.

A cam 3 is integrally provided on the surface of the intermittent gear 1,
A roller 4a of a power plate 4 is in contact with the outer periphery of this cam 3. The roller 4a is always pressed against the outer periphery of the cam 3 by the urging force of a spring 5 which urges the power plate 4 in the return direction (leftward in the figure).

As shown in FIG. 1, the cam 3 rotates clockwise in the figure together with the intermittent gear 1, and the shape from the minimum diameter part to the maximum diameter part 3a is the same as that of the conventional one. Then, between the maximum diameter part 3a and the lock part 3b, a slight slope A is formed, which is adjacent to a steep slope B, and furthermore, in front of the lock part, there is a small slope A. A step C is provided. This stepped portion C is provided in an arc shape concentric with the cam 3 with respect to the axis.

Note that the power plate 4 is locked by a locking means 6.

The operation of this embodiment having the above configuration is as follows.

That is, as shown in FIG. 2, when the roller 4a of the power plate 4 is located at the maximum diameter portion 3a of the cam 3, the power plate 4 has moved forward to the foremost position.

Next, when the roller 4a of the power plate 4 exceeds the maximum diameter part 3a of the cam 3, the power plate 4 starts to return to the left in the figure due to the urging force of the spring 5 while being guided by the gentle slope A. However, as shown in FIG. 2, the roller 4a of the power plate 4 descends the steeply inclined surface B of the cam 3, thereby rapidly falling toward the step C having a small diameter. At this time, in particular, since the shape of the stepped portion C is an arc concentric with the axis of the cam 3, most of the urging force of the return spring 5 received from the roller 4a is absorbed by the axis of the cam 3. It will take the form of Furthermore, since the power plate 4 is temporarily stopped or greatly decelerated at this stepped portion C, no rotational force is generated in the cam 3 as in the conventional case.

Even after most of the impact from the urging force of the spring 5 is lost, the intermittent gear 1 integrated with the cam 3 is rotated slightly by the drive gear 2, so that the roller 4a
moves over the step C and toward the lock portion 3b, but since the difference in diameter between the step C and the lock portion 3b is minute, the biasing force of the spring 5 applied to the power plate 4 is also minute.
The roller 4a or the power plate 4 moves at a very slow speed.

Therefore, as shown in FIG. 3, the intermittent portion 1a of the intermittent gear 1 faces the drive gear 2, so that the intermittent gear 1 and the cam 3 stop rotating, and the power plate 4 is locked by the locking means 6. When the power plate 4 moves at an extremely low speed, the impact force applied to the locking means 6 is much reduced compared to the conventional case, and the durability of the locking means 6 is improved. In this case, since the speed of the cam 3 has also been significantly reduced, there is no risk of the intermittent gear 1 and the drive gear 2 meshing again as in the past, causing the cam 3 to repeat unnecessary operations, and therefore the power plate There is no inconvenience that would cause 4 to be in an unstable locked state.

Note that the present invention is not limited to the above-mentioned embodiments. For example, the shape of the stepped portion may not be an arc concentric with the axis of the cam, but may be an inclined surface in the opposite direction to the cam, or As shown in Figure 4°, there is a protrusion 3 for the brake on the minimum diameter side of the step.
If C is provided, the impact caused when the roller contacts the stepped portion can be released in the direction opposite to the rotation of the cam, which is more effective.

[Effects of the Invention] As explained above, according to the present invention, by making a simple improvement to the shape of the cam, the impact force applied to the locking means of the power plate is reduced, and its durability is improved. Furthermore, it is possible to provide an excellent tape recorder power mechanism with more stable operation.

[Brief explanation of drawings]

1 to 3 are plan views showing an embodiment of the power mechanism of a tape recorder according to the present invention, in which FIG. 1 is an enlarged view showing a cam, and FIG. 3 is a diagram showing the state in which the roller of the power plate is in the locking part of the cam, FIG. 4 is an enlarged view showing the cam in another embodiment of the present invention, and FIG. 1 is a plan view showing an example of a power mechanism of a conventional tape recorder. DESCRIPTION OF SYMBOLS 1...Intermittent gear, 1a...Intermittent part, 2...Drive gear, 3...Cam, 3a...Maximum diameter part, 3b...Lock part, 3C...Protrusion part, 4 ...power plate,
4a... Roller, 5... Spring, 6... Locking means, A... Gentle slope, B... Sharp slope,
C... Danbe. . ltm Q 12 Figurell53 Figure

Claims (1)

[Claims] (1) Equipped with an intermittent gear that is intermittently rotated by a drive gear, and a power plate that reciprocates by the action of a cam provided on the intermittent gear, and the movement of this power plate moves each member to the play position or fast forward/rewind position. In a power mechanism of a tape recorder configured such that the power plate is locked by a locking means after a certain stroke operation, a cam provided on the intermittent gear moves the power plate to the frontmost position at the maximum diameter portion. and a lock part that makes the intermittent part of the intermittent gear face the drive gear, and a step part with a slightly larger diameter than the lock part is provided between the maximum diameter part and the lock part, and this step part has a circular arc shape concentric with the cam. Or a power mechanism of a tape recorder, characterized in that it is formed on an inclined surface in the opposite direction to the cam.