JPH042435Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an arm moving mechanism used in a cam device that converts rotational motion into linear motion.

[Background Art and Issues to be Solved] Generally, in a cam device that converts rotational motion into linear motion, the rotation of a cam, which is a driving joint, is transmitted to an arm, which is a driven joint, through a roller, etc., so that the arm moves linearly. It's getting old.

Such a cam device has a structure in which, as the cam rotates, a roller pivotally supported by one end of the arm rolls on the outer peripheral surface of the cam, and the arm moves linearly in one direction. Furthermore, by constantly bringing the roller into contact with the outer peripheral surface of the cam, the linear movement of the arm is stabilized.

Therefore, the cam device has a structure in which the roller is pressed against the outer peripheral surface of the cam by the weight of the arm or the like.

However, when the roller is pressed against the outer circumferential surface of the cam, the load of the roller on the cam increases, which causes wear of the outer circumferential surface of the cam and increases the torque of the cam.

Further, in the cam device shown in FIG. 7, as the rotating cam 10 rotates, the pin 14 connected to the arm 12 slides in a cam groove 16 provided in the normal direction of the rotating cam 10, so that the arm 12 is guided. It has a structure in which it is guided by a pin 18 and moves in a straight line.

In this cam device (shown in FIG. 7), the pin 14 slides on the cam groove 16 as in the above cam device, so the load on the rotating cam 10 of the arm 12 is large and the cam groove 16 wears out. cause
Further, since the pin 14 moves in the radial direction of the rotating cam 10 due to the rotation of the rotating cam 10, the rotating cam 10
torque increases.

The present invention takes the above facts into consideration and aims to provide an arm moving mechanism that can reduce the load on the cam.

[Summary of the invention] The arm moving mechanism according to the invention includes a rotating cam that is rotated by a driving means and has a cam groove provided in an arc shape in the circumferential direction, an arm that is guided so as to be able to reciprocate in a straight line, and one end. a cam follower that is fitted into a cam groove of the rotary cam, the other end is pivotally supported by the arm, and connects the rotary cam and the arm so as to be rotatable in a direction substantially perpendicular to the direction of linear reciprocating movement of the arm; and a biasing means for biasing the arm toward the rotating cam.

In the arm moving mechanism having the above structure, when the rotating cam is rotated by the driving means, the cam groove provided in the circular arc shape in the rotating cam is moved relative to the cam follower, and at the same time, the cam follower is rotationally moved in one direction, and the cam An end of the groove abuts one end of the cam follower.

When the rotary cam is further rotated, one end of the cam follower that is in contact with the end of the cam groove is locked to the end of the cam groove, and while being rotated in one direction, the cam follower is rotated approximately at right angles to the one direction. Moved straight in the other direction.

The arm connected to the cam follower is guided through the bearing section in the direction of linear movement of the cam follower and is moved linearly.

Next, when the rotating cam is rotated in the opposite direction by the driving means, the arm is linearly moved in the opposite direction.

[Configuration of Embodiment] FIGS. 1 to 6 show an embodiment in which the arm moving mechanism according to the present invention is used in a rotary head type video cassette tape recorder.

FIG. 1 shows a mechanism for operating arm 22 by rotation of rotary cam 20. As shown in FIG.

The rotary cam 20 is formed into a disk shape and, as shown in FIGS. 1 and 2, is provided with a driving portion 24 coaxially formed on one side and having a reduced diameter.

This rotary cam 20 is fixed to one end of a support shaft 28 with the driving portion 24 facing the substrate 26 side, and the other end of this support shaft 28 is supported pivotally inside the substrate 26 and rotates together with the rotary cam 20. It is now possible to move.

Further, a belt 3 is attached to the drive section 24 of the rotating cam 20.
0 is wrapped around it.

This belt 30 is connected to a motor (not shown) as a driving means via a pulley (not shown), and the rotating cam 20 and the support shaft 28 are rotated via the belt 30 by the drive of this motor. It's summery.

Further, a cam groove 32 is formed on the driving portion 24 side of the rotating cam 20.

The cam groove 32 extends in the circumferential direction of the rotary cam 20 with the axis of the rotary cam 20 as the center, and is formed approximately half the circumference of the rotary cam 20 .

Further, an arm 22 is arranged below the rotary cam 20 and on the substrate 26.

This arm 22 is formed from a thin plate material into a substantially F-shaped planar shape, and at the end of the side that engages with the cam groove 32 of the rotary cam 20, there is a rising portion facing in the width direction from the flat surface of the plate material. The portion is bent upward to form a bearing portion 36.

A pin 38 passes through the bearing portion 36 of the arm 22. Both ends of the pin 38 are fixed to the bearing portions 36 of the arm 22, and the pin 38 is arranged with its axial direction facing the longitudinal direction of the connecting portion 34 of the arm 22. Further, the intermediate portion of this pin 38 passes through the cam follower 40.

The cam follower 40 is formed in a cylindrical shape, and one end is pivotally supported by the pin 38, and the other end is rotatable about the pin 38. Further, a spherical portion 42 is formed on the end surface of the cam follower 40 on the other end side.

This spherical portion 42 has one end that is smaller in diameter than the cam follower 40 and is formed on the same axis as the axis of the cam follower 40, and the other end is formed into a spherical shape.

Further, this ball portion 42 is fitted into the cam groove 32 of the rotary cam 20, so that the arm 22 is moved by the rotation of the rotary cam 20.

In the vicinity of the connecting portion 34 of the arm 22, a guide pin 44 is erected on the base plate 26 adjacent to the end surface of the connecting portion 34 in the width direction. This guide pin 44 is formed in a cylindrical shape, and one end is attached to the base plate 26 and the other end has a larger diameter than the one end, and limits the movement of the arm 22 in the linear direction, and also connects the arm 22 to the base plate 26. It is designed for installation.

Further, a hook portion 46 is formed on a curved portion protruding from the longitudinally intermediate portion of the connecting portion 34 of the arm 22, and the tip of the leg portion of this hook portion 46 is bent upward. There is.

At the intermediate part between the hook part 46 and the bearing part 36,
A support pin 48 is provided upright on the substrate 26 adjacent to the end face in the width direction of the connecting portion 34 .

One end of a tension coil spring 50, which is a biasing means, is hooked to this support pin 48. The other end of this tension coil spring 50 is the hook portion 46 of the arm 22.
The arm 22 is urged in the direction from the latching part 46 toward the bearing part 36, and the ball part 42 of the cam follower 40 is pushed toward the longitudinal end of the cam groove 32 via the pin 38. It's pressing.

Further, a push pin 52 is provided upright at one end in the longitudinal direction of the connecting portion 34 of the arm 22 and not connected to the bearing portion 36 .

A tension arm 54 is arranged near this push pin 52.

The tension arm 54 is formed from a thin plate material into a substantially U-shape in plan view, and has a shaft 56 erected on the base plate 26 at a connecting portion connected to one end.
A connecting portion that is pivotally supported by the push pin 52 and connected to the other end is disposed above the arm 22 and abuts the tip of the push pin 52 .

Also, the push pin 5 of this tension arm 54
A pole 58 is erected at the tip of the second end, and a hanging shaft 60 is erected near the tip of the other end.

One end of a tension coil spring 62 is latched to this latching shaft 60 . This tension coil spring 62 has its other end hooked to one end of a tension arm 54 disposed near the hook shaft 60, and moves a pole 58 erected on the tension arm 54 in a counterclockwise direction. It is energizing.

The tension arm 54 is rotated counterclockwise about a shaft 56 as the arm 22 moves in the direction of arrow A due to the rotation of the rotary cam 20.

Further, as shown in FIG. 3, this tension arm 54 is arranged on the left side of the video cassette tape recorder.

This video cassette tape recorder is equipped with a rotary head 64 in the center, and the rotary head 64 rotates during play.

Further, in this video cassette tape recorder, a pair of substantially V-shaped grooves 66 are formed in the tangential direction of the rotary head 64 and adjacent to the rotary head 64. One end of a tape guide 70 with 68 is fitted therein.

The tape guide 70 is disposed at one end of a pair of grooves 66 that are close to each other, and is moved to the other end of the groove 66 while being guided through the groove 66 by a loading motor (not shown) during loading. ing.

A pinch roller arm 74 having a pinch roller 72 at one end is disposed on the right side of the video cassette tape recorder.

This pinch roller arm 74 has an intermediate portion that is attached to the substrate 2.
6, and is rotatably supported by a support shaft 76 fixed to 6, so that it rotates clockwise during loading.

This rotational movement of the pinch roller arm 74 causes the pinch roller 72 to come into contact with a capstan 78 attached to the base plate 26.

When the cassette tape 80 is loaded into this video cassette tape recorder, the supply reel 82 of the cassette tape 80 is connected to the tension arm 54.
To the sides, the take-up reams 84 are respectively arranged on the side of the pinch roller arms 74 .
In addition, the supply reel 82 of this cassette tape 80
The magnetic tape 86 wound around the take-up ream 84 is arranged adjacent to the pinch roller 72, the pole 58, and the tape guide pin 68, respectively.

[Operation of the embodiment] As shown above, when loading the video cassette tape recorder to which the arm moving mechanism according to the present embodiment is attached, the cassette tape 8
After 0 is loaded, a loading motor (not shown) is driven.

By this driving of the loading motor, the tape guide pin 68 is guided into the groove 66 together with the tape guide 70, as shown in FIG.
Moved to the 4th side.

As the tape guide pin 68 moves, the pinch roller 72 is rotated clockwise together with the pinch roller arm 74 and is pressed against the capstan 78 via the magnetic tape 86.

Further, simultaneously with the movement of the tape guide pin 68, a motor (not shown) connected to the rotary cam 20 via the belt 30 is driven.

By driving this motor, the rotary cam 20 moves to the fifth position.
When rotated counterclockwise as shown in the figure, the ball portion 42 of the cam follower 40 is rotated by the tension coil spring 5.
It rotates as the cam groove 32 rotates while being pressed against one end in the longitudinal direction of the cam groove 32 by an urging force of zero.

The cam follower 40 connected to the ball portion 42 is rotated about the pin 38 as the ball portion 42 moves, and linearly moved in the axial direction of the pin 38 .
Further, the movement of the pin 38 of the cam follower 40 in the axial direction is transmitted to the arm 22 via the bearing portion 36, and the arm 22 is guided by the guide pin 44 and moved in the direction of arrow A.

As the push pin 52 connected to the arm 22 moves in the direction of arrow A, the tension arm 54 is rotated counterclockwise by the biasing force of the tension coil spring 62.

When the rotating cam 20 is further rotated clockwise, as shown in FIG. 44 and stops.

At the same time as the movement of the arm 22 is stopped, the ball portion 42 of the cam follower 40 is separated from one end of the cam groove 32 in the longitudinal direction, guided by the cam groove 32, and moved to an intermediate portion of the cam groove 32.

Further, the push pin 52 is spaced apart from the tension arm 54, and the tension arm 54 is separated from the pole 58.
The rotational movement is restricted through the magnetic tape 86 to detect the tension of the magnetic tape 86.

Further, during loading, the rotation of the rotary cam 20 is stopped immediately after the movement of the arm 22 is stopped, and the cam follower 40 is supported by the pin 38 with its axis oriented substantially vertically as shown in FIG.

Next, when unloading the magnetic tape 86, the rotary cam 20 is rotated counterclockwise, so that the arm 22 and the tension arm 54 are operated in the opposite direction to that during loading.

In the arm moving mechanism according to this embodiment, as shown above, the ball portion 42 of the cam follower 40 fitted into the cam groove 32 of the rotary cam 20 is rotatable about the pin 38 together with the cam follower 40. , arm 3 due to rotation of rotating cam 20
4, the load on the rotating cam 20 can be made smaller than in the past. Furthermore, even when the ball portion of the cam follower 40 slides in the cam groove 32 of the rotary cam 20, the load on the rotary cam 20 can be made smaller than before.

Furthermore, in the arm moving mechanism according to the present embodiment, since the cam groove 32 is provided in an arc shape centered on the axis of the rotary cam 20, the torque of the rotary cam 20 fluctuates greatly when the rotary cam 20 rotates. Never.

Note that the arm moving mechanism according to this embodiment may have another structure, such as one in which the linked arm 22 is moved linearly above the rotating cam 20.

Further, in the arm moving mechanism according to the present embodiment, one end of the cam follower 40 that is fitted into the cam groove 32 of the rotary cam 20 is a spherical portion 42, but the cam follower 40 is not limited to this. It is fitted into the cam groove 32 of the rotary cam 20, and the other end is supported rotatably around a pin 38 in a direction substantially perpendicular to the linear movement direction of the arm 22.

[Effect of the invention] As explained above, the arm moving mechanism according to the present embodiment includes a rotary cam that is rotated by the driving means and has a cam groove provided in an arc shape in the circumferential direction, and a guide that can reciprocate in a straight line. One end of the arm is fitted into a cam groove of the rotary cam, the other end is pivotally supported by the arm, and the rotary cam and the rotary cam are rotatable in a direction substantially perpendicular to the direction of linear reciprocating movement of the arm. Since it has a cam follower that connects the arm and a biasing means that biases the arm toward the rotating cam, it has the excellent effect of reducing the load on the cam.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the arm moving mechanism according to the present invention, and FIG. 1 shows a part of the video cassette tape recorder in which the embodiment is attached to the video cassette tape recorder. The plan view shown in Fig. 2 is a cross-sectional view taken along the line -
The figure is a plan view showing the structure of a part of the video cassette tape recorder, FIG. 4 is a plan view showing the operating state of FIG. 3, FIG. 5 is a plan view showing the operating state of FIG. 1, and FIG. FIG. 5 is a cross-sectional view taken along the - line, and FIG. 7 is an explanatory diagram showing a conventional arm moving mechanism. 20... Rotating cam, 22... Arm, 32...
Cam groove, 36...Bearing section, 38...Pin, 40...
...Cam follower, 42...Ball portion, 50...Tension coil spring (biasing means).

Claims (1)

[Scope of utility model registration request] A rotary cam that is rotated by a driving means and has a cam groove provided in an arc shape in the circumferential direction, an arm that is guided so as to be able to reciprocate on a straight line, one end of which is fitted into the cam groove of the rotary cam, and the other end of which is a cam follower that is pivotally supported by the arm and connects the rotary cam and the arm so as to be rotatable in a direction substantially perpendicular to the linear reciprocating direction of the arm; and an urging force that biases the arm toward the rotary cam. An arm moving mechanism comprising: means.