JPH041936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cam drive device for switching operating modes using the rotational force of a motor in a magnetic recording/reproducing device.

Conventional configurations and their problems In recent years, magnetic recording and reproducing devices that use the rotational force of a motor to switch between operating modes without using direct manual force have become popular.
Among them, there are those that use a gear cam with a toothless part to utilize the rotational force of the motor, and use the small force of the drive trigger of the gear cam as the operating force.
A method has been proposed in which the trigger is activated by one reciprocating motion (wump push) of a button, so that the trigger can be operated as if it were operated by an electric switch.

A conventional cam drive device will be described below with reference to FIGS. 1, 2, and 3. FIG. 1 is a plan view of a conventional cam drive device, in which 1 is a drive gear that is constantly rotated by a motor, 2 is a cam gear, and the gear part includes toothless parts 2a and 2b, and the center part of the surface is a cam gear. A cam surface (not shown) is provided on the rear surface of the engaging portion 2c. 3 is the engaging part 2c
The eccentric cam shape of the engaging portion 2c urges the cam gear 2 to rotate counterclockwise.

A control arm 4 is pivotally supported by a shaft 5 mounted on a mechanical chassis, and is urged by a spring 6 to rotate clockwise. Reference numeral 7 indicates an operating button, and 8 indicates an operating rod which is slidable guided by a pin 13 and biased in one direction by a spring 14. Reference numeral 9 denotes an operating arm rotatably supported by a shaft 10 mounted on the operating rod 8, and is urged by a spring 11 to rotate counterclockwise. 12 is a pin that locks the rotation of the operating arm 9 by the spring 11.

The operation of the cam drive device configured as described above will be explained below.

First, FIG. 1 shows a state in which the operation button 7 is not pushed in, and one end 4a of the control arm 4 is connected to the cam gear 2.
The cam gear 2 is engaged with the engaging portion 2c of the spring 3.
The biasing force prevents it from rotating counterclockwise. In this state, the cam gear 2 has a missing tooth portion 2a.
is located at a position corresponding to drive gear 1, so the rotational force of drive gear 1 is not transmitted to cam gear 2.

Next, push in the operation button 7 and the operation rod 8 will be pressed.
The operating arm 9, which is pivotally supported, moves in the direction of arrow A. As a result, the protrusion 4b of the control arm 4 is pushed by the protrusion 9a of the operating arm 9, and the control arm 4 is rotated counterclockwise against the biasing force of the spring b. Then, the engagement between the one end 4a of the control arm 4 and the engagement portion 2c of the cam gear 2 is released. Then, the cam gear 2 rotates slightly counterclockwise under the urging force of the spring 3, and the gear portions of the drive gear 1 and cam gear 2 mesh with each other, and the rotational force of the drive gear 1 is transmitted to the cam gear 2. As shown in FIG. 3, this rotational force transmission stops when the cam gear 2 rotates half a turn and the toothless portion 2b reaches a position facing the drive gear 1, and this state is maintained when the one end 4a of the control arm 4 and the cam gear 2 are engaged. It is held by the engagement of the joint portion 2c.

Note that, as the cam gear 2 rotates, any driving force is transmitted from the cam surface formed on the back surface to other mechanisms. Then, when the pressing force on the operating button 7 is released, the operating arm 9 is rotated clockwise by the urging force of the spring 13 against the urging force of the spring 11, and the operating rod 8 is returned to its original position without moving the control arm 4.

As described above, the cam gear 2 can be triggered by one reciprocating movement (wamp push) of the operation button 7, regardless of the duration of the push.

However, according to the above configuration, mechanical parts such as the control arm 4 and the operation arm 9 are required in order to reliably operate the cam gear 2 and switch one operation mode with one reciprocating movement of the operation button 7. As the number of points increases, the cost becomes high, and it is also disadvantageous in terms of space, which hinders miniaturization.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and provides a cam drive device that has a simple configuration with a reduced number of parts and can reliably trigger a cam gear with one reciprocating movement of an operation button. The purpose is to

Structure of the Invention The present invention has a motor, a drive gear that is decelerated by the motor, a cam surface that is in a meshing position with the drive gear and transmits power to another mechanism, and has a first toothless portion and a second toothless portion. A cam gear having at least one or more pairs of toothless parts, and first and second toothless parts, respectively, so as to lock the cam gear correspondingly when the first and second toothless parts face the drive gear. The cam drive device is equipped with an operation member that assumes two positions, and the cam surface from the first toothless portion to the second toothless portion transmits the rotational force of the motor as power to another mechanism,
The cam surface from the second toothless portion to the first toothless portion is configured to maintain the state of the cam surface and not transmit power to other mechanisms, and the reciprocating movement of the operating member between the first and second positions. This is how the power is obtained from the cam gear.

DESCRIPTION OF EMBODIMENTS FIG. 4 shows a plan view of a cam drive device in an embodiment of the present invention. In Figure 4,
Reference numeral 20 is a drive gear that is constantly rotating by being decelerated by a motor, and 21 is a cam gear, the outer periphery of which is provided with toothed portions 22a, 22b, 22c, 22d, first toothless portions 23a, 23c, second toothless portions 23b, It has 23d. 24a, 24b, 24c, and 24d are engagement protrusions integrally formed on the surface of the cam gear 21, respectively, and 25 is a cam integrally provided on the back surface of the cam gear 21.

Further, as shown in FIG. 7, the back surface of the cam gear 21 has a cam surface (cam groove) 35, and the cam gear 21
The pin 3 is guided by the cam surface 35 according to the rotation of the pin 3.
The operating force for the other mechanisms is taken out by a lever 37 with 6. Reference numeral 26 denotes a spring whose one end abuts against the cam 25 and always urges the cam gear 21 to rotate counterclockwise.

27 is an operation button, 28 is an operation rod for the operation button 27, which has a protrusion 28a at one end, and is always connected to a spring 29.
energized by. 30 is a guide bin.

The operation of the above configuration will be explained below.

First, when the operation button 27 is not operated, that is, in the first position, it is in the state shown in FIG.
The cam gear 21 is biased to rotate counterclockwise due to the abutment of the cam gear 21, but since the protrusion 28a of the operating rod 28 is engaged with the engagement protrusion 24b of the cam gear 21, the rotation in the counterclockwise direction is prevented. blocked. At this time, the first toothless portion 23a of the cam gear 21
is opposed to the drive gear 20, so this rotational force is not transmitted to the cam gear 21.

Next, when the operation button 27 is pushed in against the biasing force of the spring 29, that is, in the second position of the operation member, the engagement between the projection 28a and the engagement projection 24b is disengaged, and the spring 2
The cam gear 21 is slightly rotated counterclockwise by the biasing force 6. As a result, the tooth portion 22a of the cam gear 21 meshes with the drive gear 20 and rotational force is transmitted. This state is shown in FIG.

The rotational force of the drive gear 20 rotates the cam gear 21, and as shown in FIG. It is configured such that the amount of movement is taken out as a driving force for other mechanical parts.

Further, if the operation button 27 is continued to be pressed from the state shown in FIG. 5, the teeth 22a of the cam gear 21
At a position where the cam gear 21 is slightly rotated by the biasing force of the spring 26 after the meshing is finished, the protrusion 28a engages with the engagement protrusion 24c, and further rotation is prevented. At this time, the second toothless portion 23b is connected to the drive gear 2.
0, and the rotational force of the drive gear 20 is not transmitted.

In this state, as shown in FIG. 7c, the movement of the lever 37 due to the displacement of the cam surface 35 has ended, and the driving of other mechanical parts has ended.

When the operating button 27 is returned from this state, that is, when the operating member is returned from the second to the first position, the engagement between the protrusion 28a and the engagement protrusion 24c is released.
The cam gear 21 rotates slightly counterclockwise due to the urging force of the drive gear 20 and the cam gear 21.
The cam gear 21 rotates due to the rotational force generated by the meshing with the teeth 22b, and the engagement protrusion 24a and the protrusion 28a rotate.
Rotation stops at the engaged position. At this time, the drive gear 20 is in a position facing the first toothless portion 23c. Further, the cam gear 21 is connected to the protrusion 28a and the engagement protrusion 2.
Although the cam surface 35 rotates for a short time after the engagement of the protrusion 4c is released and the engagement protrusion 24a is engaged with the protrusion 28a, there is no displacement of the cam surface 35 (the length from the center of the cam to the groove of the cam) during this time. The lever 37 is configured not to be moved. Therefore, other mechanical parts are not driven.

Next, when the operation button 27 is pushed in, that is, when the operation member is moved to the second position again, the engagement between the protrusion 28a and the engagement protrusion 24a is released, the teeth 22c engage with the drive gear 20, and the drive gear 20 The rotational force is transmitted to the cam gear 21, and the lever 37 is moved by the cam surface 35 in the direction opposite to the direction of arrow B, thereby returning the other mechanical parts to their original positions. If the operation button 27 is kept pressed when the teeth of the drive gear 20 and the cam gear 21 have finished meshing, the protrusion 2
8a engages with the engagement protrusion 24d, and then the operation button 2
7 is returned, the engagement between the protrusion 28a and the engagement protrusion 24d is released, and the cam gear 21 rotates a little due to the biasing force of the spring 26, further causing the drive gear 20 and the tooth portion 22 to rotate.
After rotating with the engagement shown in FIG. 4, the protrusion 28a engages with the engagement protrusion 24b to stop the rotation and return to the original position shown in FIG. This drive gear 20 is a cam gear 21
While the cam surface 35 faces the second tooth-missing portion 23d, the tooth portion 22d, and the first tooth-missing portion 23a in sequence, there is no displacement of the cam surface 35, and no driving force is transmitted to other mechanical parts.

Further, if the operation button 27 is pressed to release the engagement between the protrusion 28a and the engagement protrusion 24b from the state shown in FIG.
8a does not engage with the engagement protrusion 24c, and the cam gear 21 rotates until it engages with the engagement protrusion 24a. During this time, as described above, while the driving gear 20 and the tooth portion 22a are engaged and the driving force is being transmitted, other mechanical portions are being driven by the lever 37 from the cam surface 35.

Thereafter, the above operation is repeated every time the operation button 27 is pressed.

As described above, according to this embodiment, the protrusion 2
8a and engaging protrusions 24a, 24b, 24c, 24d
Due to the engagement relationship between the first and second positions of the operation button 27, the cam gear 21 can be reliably triggered once by pressing the operation button 27 back and forth between the first and second positions, regardless of the time it is pressed, and the operation is stable. It is something that exists.

Further, since the cam surface 35 is formed so that the other mechanical parts are driven while the teeth 22a and 22b of the cam gear 21 are engaged, the operation is stable.

Further, when the protrusion 28a disengages from the engagement protrusion 24c and engages with the engagement protrusion 24a, that is, when the drive gear 20 moves from the position facing the second toothless portion 23b to the first tooth When moving to the position facing the cutout 23c, the cam gear 21 is moved using the driving force of the drive gear 20 via the teeth 22b, so that the operation is performed reliably.

Further, the number of parts is smaller than that of the conventional example, the structure is simple, and the space required is small, making it possible to downsize.

Effects of the Invention The present invention provides one or more pairs of locking positions for the two toothless portions to correspond to the two positions of the operating rod, and uses the rotational force of the motor to move the two toothless portions. As a result, the cam can be triggered by one reciprocating movement of the operation button regardless of how long it is pressed, reducing the number of parts compared to conventional methods, and realizing a cam drive device that is advantageous in terms of cost and space. It is something.

[Brief explanation of drawings]

1 to 3 are plan views showing a conventional cam drive device, FIGS. 4 to 6 are plan views showing a cam drive device according to an embodiment of the present invention, and FIG. 7 is a plan view showing a cam drive device according to an embodiment of the present invention. FIG. 3 is a plan view showing a cam surface. 20... Drive gear, 21... Cam gear, 23
a, 23c...first tooth-missing portion, 23b, 23d...
...Second tooth missing portion, 24a, 24b, 24c, 24
d...Engagement protrusion, 26...Spring, 28...Operation rod, 28a...Protrusion.

Claims (1)

[Claims] 1 A motor, a drive gear that is decelerated from the motor, a cam surface that is in a position to mesh with the drive gear and transmits power to another mechanism, and a pair of first toothless part and second toothless part. A cam gear having at least one pair of toothless parts and tooth parts formed adjacent to the first toothless part and the second toothless part, and the first and second toothless parts are driven. The cam surface of the first toothless portion to the second toothless portion is provided with an operation member that takes a first position and a second position so as to lock the cam gear when facing the gear, respectively. In this case, the rotational force of the motor is transmitted as power to other mechanisms, and the cam surface from the second toothless portion to the first toothless portion is configured to maintain the state of the cam surface and not transmit power to other mechanisms. A cam drive device characterized in that the power of the cam gear is obtained by the reciprocating movement of the operating member between the first and second positions.