JPH0815510B2 - Overrun prevention device for feed cam in cycle sewing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed cam overrun prevention device in a cycle sewing machine applied to boring and the like.

[0002]

2. Description of the Related Art First, a conventional feed cam overrun prevention device in the above-described cycle sewing machine will be described with reference to FIGS.

An overrun prevention device 1 for a feed cam in a cycle sewing machine of this type is supported by a frame (not shown), and an input shaft 2 having a drive pulley 3 fixed to one end thereof.
The rotary drive force of an electric motor or the like, which is a drive source (not shown), is transmitted to the drive pulley 3 of the input shaft 2 by a V belt or a timing belt.
Then, by rotating the drive pulley 3 in the direction of arrow A in FIG. 5, the input shaft 2 is rotated in the same direction, and the worm 4 that is the input side of the reduction gear fixed to the appropriate position of the input shaft 2 is fixed. The rotational force of the worm 4 that is the input side of the reduction gear transmission is transmitted to the worm wheel 5 that is the output side of the reduction gear transmission in the direction of arrow B in FIG. It is designed to rotate the worm wheel 5.

The worm wheel 5 is rotatably loosely fitted to a horizontal shaft 6a supported by a bearing (not shown), and a clutch collar 8 is fixed to the horizontal shaft 6a by a set screw 7. There is. Then, the rotational force of the worm wheel 5 is transmitted to the clutch collar 8 via a substantially cylindrical one-way clutch spring 10 having one end engaged with an engagement hole 9 provided at an appropriate position of the worm wheel 5. It is being transmitted. The one-way clutch spring 10 is fitted on the outer periphery of the clutch collar 8 with a desired tightening margin, and the worm wheel 5 is provided.
5 is wound in a direction in which the inner diameter is reduced when it is rotated in the direction of arrow B in FIG. Then, when the worm wheel 5 rotates, the one-way clutch spring 10 gradually reduces in diameter from one end engaged with the worm wheel 5, the sliding resistance with the clutch collar 8 increases, and the rotational driving force is increased. It can be transmitted to the clutch collar 8.

A spur gear 12a is provided at one end of the horizontal shaft 6a through a connecting collar 11 to the worm wheel 5a.
It is arranged so as to rotate in the direction of arrow C in FIG. The spur gear 12a is meshed with a spur gear 12b fixed to one end of a horizontal shaft 6b arranged in parallel with the horizontal shaft 6a by a bearing (not shown). Gear 1
2b is rotated in the direction of arrow D in FIG.

Further, a screw gear 13a is fixed to the other end of the horizontal shaft 6b. This screw gear 13a
Is meshed with a screw gear 13b fixed to the upper side in FIG. 5, which is one end of the drive shaft 14 vertically arranged by a bearing (not shown), and the drive shaft 14 is rotated by the screw gear 13a. It is adapted to rotate in the direction of arrow E in FIG. A drive gear 17, which is a spur gear that meshes with a tooth portion 16 provided on the outer circumference of the feed cam 15, is fixed to the lower end, which is the other end of the drive shaft 14. Then, the feed cam 15 is rotated by the drive gear 17 in the direction of arrow F in FIG.

The feed cam 15 is formed in a substantially disc shape, and a through hole 18 provided in the shaft center portion is rotatably supported by a support shaft provided at an appropriate position of a frame (not shown). Are arranged. Further, a flat cam 19 or the like is formed on the upper surface in the drawing which is one surface of the feed cam 15 in the axial direction, and a groove cam for boring is formed on the lower surface which is the other surface of the feed cam 15 in the drawing. Various cams 20 are formed, and a feeding mechanism (not shown) is reciprocated.

The flat cam 19 is, as shown in FIG.
A desired step in the axial direction is provided on a plane projecting in an annular shape on the upper surface of the feed cam 15, and the step is connected by an inclined surface 21. Further, a bell crank-shaped needle swing control arm 22 rotatably supported by a horizontal support pin 22c is disposed above the plane cam 19, and the needle swing control arm 22 is almost free. A cylindrical roller 23 is rotatably disposed at the tip of the horizontal arm 22a extending in the horizontal direction. And this cylindrical roller 2
3 is in contact with the flat cam 19.

Further, the needle swing control arm 22 is urged at the distal end of the vertical arm 22b extending substantially vertically to rotate the needle swing control arm 22 clockwise in FIG. One end of a pulling spring 24 is locked, and the cylindrical roller 23 is brought into contact with the flat cam 19 with a desired pressing force.

By the way, as shown in FIG. 7, when the sewing machine is stopped by a stop instruction, the flat roller cam 19 of the feed cam 15 of the cylindrical roller 23 is inclined as shown in FIG. It stops at the position where it always contacts the surface 21. Therefore, the cylindrical roller 23 stops in a state of being in pressure contact with the inclined surface 21 of the flat cam 19, which provides a force for rotating the feed cam 15 in the direction indicated by the arrow F in FIG. At this time, even if the rotation of the drive pulley 3 is stopped, the rotational force reversely transmitted from the feed cam 15 acts in the direction of expanding the diameter of the one-way clutch spring 10 to cause the worm wheel 5 to move.
One end engaged with is fixed and the other end is rotated by the clutch collar 8 in the direction of arrow C shown in FIG. As a result, the clutch collar 8 rotates, and it is impossible to prevent the rotational force that is transmitted in reverse. Therefore, the feed cam 15 overruns and rotates in the direction indicated by the arrow F in FIG. As a result, the feeding operation and the like are performed even when the driving force of the sewing machine is stopped.

Therefore, conventionally, as shown in FIGS. 5 and 7, a groove 25 having a substantially semicircular cross section is formed in the circumferential direction of the outer peripheral surface of the feed cam 15, and a brake spring 26 is provided in the groove 25.
Thus, the brake band 27, which generates an appropriate frictional resistance when the feed cam 15 overruns, is arranged so as to always come in contact with a desired pressing force to prevent the feed cam 15 from overrunning.

[0012]

However, in the feed cam overrun prevention device 1 in the above-described conventional cycle sewing machine, the feed cam 15 is always provided with the brake band 27 in order to prevent the feed cam 15 from overrunning. Since they are in contact with each other, the rotation torque of the feed cam 15 increases, and a drive motor with a large capacity must be used, and the transmission torque applied to each gear train increases, shortening the life of each gear. There was a problem. Further, since the brake band 27 and the groove 25 of the feed cam 15 are always in contact with each other, the frictional resistance between the brake band 27 and the groove 25 formed on the feed cam 15 is inevitably changed with the lapse of time. There was a problem.

The present invention overcomes the above-mentioned problems in the prior art and prevents the overrun of the feed cam with high reliability by a simple structure without applying a brake band. It is an object to provide a run prevention device.

[0014]

An overrun prevention device for a feed cam in a cycle sewing machine according to the present invention includes a speed reducer composed of a worm and a worm wheel for reducing the rotational driving force of a drive source rotationally driven in one direction. a clutch spring means for transmitting the rotational driving force of the worm wheel on the output side of the reduction gear device to the feed cam of the driven side, to transmit the clutch spring means, a cam feeding rotational output by the speed reduction device Composed of a one-way clutch spring wound in one direction and a reverse clutch spring wound in a direction opposite to the winding direction of the one-way clutch spring, and one end of the one-way spring is locked to the worm wheel. In addition, in the mounted state, the inner circumference of the reverse clutch spring is inscribed in the outer circumference of the one-way clutch spring so as to be integrally formed. It is.

[0015]

According to the feed cam overrun prevention device in the cycle sewing machine of the present invention, when the rotational drive force is transmitted from the drive source, the one-way clutch spring of the clutch spring means contracts and slides as in the conventional case. The resistance can be increased and the driving force can be transmitted to the feed cam. When the feed cam tries to overrun after the rotation driving force from the drive source is stopped, the one-way clutch spring tries to expand its diameter by the rotation driving force reversely transmitted to the clutch spring means, but the one-way clutch The reverse clutch spring on the outside of the spring tries to reduce the diameter, preventing the one-way clutch spring whose one end is locked by the worm wheel in the fixed state from expanding and generating load torque in the clutch spring means. It is possible to stop the reversely transmitted rotational driving force generated when the feed cam tries to overrun.

[0016]

The present invention will be described below with reference to the embodiments shown in the drawings. Note that the same or corresponding configurations as those of the conventional one described above are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

As shown in FIGS. 1 to 4, in the present embodiment, the rotational driving force of an electric motor or the like, which is a drive source (not shown), is decelerated by a speed reducer including a worm 4 and a worm wheel 5, and a clutch spring is used. The brake band 27 is formed so as to be transmitted to the feed cam via the means 34, and is urged by a groove 25 provided in the conventional feed cam 15 and a brake spring 26 abutting the groove 25.
And have been removed. The clutch spring means 34 is formed integrally with the one-way clutch spring 10 by mounting the reverse clutch spring 29 on the outside thereof.

Further, the clutch spring means 34 will be described. As shown in FIG. 2, the clutch collar 8 is wound around the outer periphery of the clutch collar 8 in a direction in which the inner diameter is reduced when the worm wheel 5 rotates in the direction for transmitting the driving force. A rotated one-way clutch spring 10 is fitted with a desired interference, and one end of this one-way clutch spring 10 is fitted into an engagement hole 9 provided at an appropriate position of the worm wheel 5. Are engaged with each other to transmit the driving force. The rotation of the worm wheel 5 reduces the diameter of the one-way clutch spring 10, the sliding resistance between the one-way clutch spring 10 and the clutch collar 8 increases, and the rotational driving force is transmitted. The fixation of one end of the one-way clutch spring 10 and the worm wheel 5 is not particularly limited to the engagement hole 9 as in the present embodiment, but may be fixed by an appropriate method such as bolting. It is better, and it is even better if they are connected in a decomposable state.

A reverse clutch spring 29, which is a one-way clutch spring wound in the opposite direction to the one-way clutch spring 10, is wound around the outer periphery of the one-way clutch spring 10 with a desired tightening margin. It has been turned. An annular hugging collar 30 having an appropriate tightening allowance is attached to the outer circumference of the reverse clutch spring 29, and a tightening allowance of the hugging collar 30 is adjusted by a screw 31. As a result, the one-way clutch spring 10 and the reverse clutch spring 29 are integrated into the clutch collar 8.
It is designed to be attached with an appropriate tightening margin.

The hugging collar 30 is not particularly limited to this embodiment, and the one-way clutch spring 1 is used.
0 and the reverse clutch spring 29 are integrated, for example,
A hose band or the like may be used as long as it can prevent the one-way clutch spring and the reverse clutch spring from coming off.

Further, the feed cam 32 applied to this embodiment.
Unlike the conventional example, only the tooth portion 16 meshed with the drive gear 17 is formed on the outer peripheral surface 33 of. Others are formed similarly to the above-mentioned conventional example.

Next, the operation of this embodiment having the above-mentioned structure will be described.

When the sewing machine is driven to transmit the driving force, it operates in the same manner as the above-mentioned conventional example.

As shown in FIGS. 3 and 4, when the sewing machine is stopped by a stop instruction, the cylindrical roller 23 stops at the position where it abuts the inclined surface 21 of the flat cam 19. At this time, the cylindrical roller 23 presses the inclined surface 21 of the flat cam 19, so that the feed cam 32 overruns in the direction indicated by the arrow F in FIG. 1 as in the conventional example.
This overrunning force is reversely transmitted from the feed cam 32 to the drive source side and then transmitted to the clutch spring means 34.
Then, in the clutch spring means 34, the reversely transmitted rotational force acts in a direction of expanding the diameter of the one-way clutch spring 10 (one end of the one-way clutch spring 10 engaged with the worm wheel 5 is in a fixed state, The other end is given rotation by the clutch collar 8 in the direction of arrow C shown in FIG. 1)
However, the reverse clutch spring 29, which is wound around the outer circumference of the one-way clutch spring 10 and is integrated, acts in the direction of reducing the diameter, and the diameter expanding operation of the one-way clutch spring 10 and the reverse clutch spring 29 are performed.
With the diameter reduction operation, load torque is generated, and the connection state between the one-way clutch spring 10 and the clutch collar 8 can be maintained. The rotational force reversely transmitted from the feed cam 32 has one end fixed. It can be stopped by the load torque generated in the clutch spring means 34 that is locked to the clutch 5.

The length and the mounting position of the reverse clutch spring 29 and the embracing collar 30 with respect to the one-way clutch spring 10 may be the length and the mounting position capable of exhibiting the above functions.

Therefore, even if the cylindrical roller 23 arranged on the needle swing control arm 22 stops on the inclined surface 21 of the flat cam 19 formed on the feed cam 32, the feed cam 32 is held at the stop position. You can Also, since the feed cam prevents the feed cam from overrunning, a drive motor with a smaller capacity than before can be applied to reliably prevent the feed cam from overrunning, and it is less likely to change over time and has a highly reliable cycle. It becomes a feed cam overrun prevention device in the sewing machine.

The present invention is not limited to the above embodiment, but can be modified as necessary.

[0028]

As described above, according to the feed cam overrun prevention device in the cycle sewing machine of the present invention, the feed cam is formed by the clutch spring means in which the reverse clutch spring is arranged on the outer periphery of the one-way clutch spring. Even if the cylindrical roller placed on the needle swing control arm stops due to the inclined part of the flat cam, the feed cam can be held at that stop position, and the overrun of the feed cam is ensured with a simple structure. In addition to the above, the capacity of the drive motor can be reduced, the durability can be improved and the high reliability can be maintained for a long period of time, and an extremely economical effect can be achieved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts showing an entire embodiment of a feed cam overrun prevention device in a cycle sewing machine of the present invention.

FIG. 2 is a front view of the main part of FIG.

FIG. 3 is a diagram illustrating a state where a feed cam overrun occurs.

FIG. 4 is a development view illustrating a plane cam of a feed cam.

FIG. 5 is an exploded perspective view of essential parts showing the entire feed cam overrun prevention device in a conventional cycle sewing machine.

6 is a front view of the main part of FIG.

FIG. 7 is a front view of a main part for explaining a stopped state of a feed cam.

[Explanation of symbols]

 2 Input Shaft 4 Worm 5 Worm Wheel 6a, 6b Horizontal Shaft 8 Clutch Collar 9 Engagement Hole 10 One-way Clutch Spring 12a, 12b Spur Gear 14 Drive Shaft 19 Planar Cam 21 Slope 23 Cylindrical Roller 29 Reverse Clutch Spring 30 Feed Cam 33 Outer peripheral surface 34 Clutch spring means

Claims (1)

[Claims] 1. A speed reducer comprising a worm and a worm wheel for reducing the rotational drive force of a drive source rotationally driven in one direction, and a rotational drive force of a worm wheel, which is an output side of the speed reducer, on a driven side. A one-way clutch spring wound around the clutch spring means in a direction for transmitting the rotational output from the speed reducer to the feed cam; and a winding of the one-way clutch spring. A reverse clutch spring wound in the opposite direction to the turning direction, one end of the one-way spring is locked to the worm wheel, and the one-way clutch spring has an outer circumference of the one-way clutch spring in the mounted state. An overrun prevention device for a feed cam in a cycle sewing machine, wherein the inner periphery is inscribed and integrally formed.