JP2002165663A - Ratchet type drive mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a ratchet type drive mechanism. SOLUTION: This ratchet type drive mechanism comprises a ratchet gear 7 having ratchet teeth 9 on the circumference, a ratchet L to be engaged with the ratchet teeth 9 of the ratchet gear 7, an operation lever 21 for operating the ratchet L, and a neutral returning mechanism T for returning each of the ratchet L and the operation lever 21 to a neutral position. In the neutral returning mechanism T, one return spring end 26 and the other return spring end 27 at both ends of a center return spring 25 formed in a twisted coil shape are elastically hooked with spring hooking parts 28 provided in an optional fixed part, respectively, and an engagement body 30 provided on the ratchet L or operation lever 21, which abuts on the one return spring end 26 and the other return spring end 27 to elastically deform the center return spring 25, is arranged between the one return spring end 26 and the other return spring end 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ratchet type driving mechanism.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 11-342036 discloses a ratchet gear having ratchet teeth on the outer periphery, a ratchet engaging with the ratchet teeth of the ratchet gear, and an operation lever for operating the ratchet. In the apparatus having a neutral return mechanism for returning each of the ratchet and the operation lever to a neutral position, a configuration is described in which two coil center return springs are provided on the outer periphery of the rotating body and are respectively pulled in opposite directions. I have.

[0003]

In the above-mentioned known example, since two tension coil center return springs are provided, there is a problem that a large mounting and working space are required and the device becomes large.

[0004]

An object of the present invention is to reduce the size of a ratchet drive mechanism.

[0005]

SUMMARY OF THE INVENTION The present invention provides a ratchet gear 7 having ratchet teeth 9 on its outer periphery, a ratchet L engaged with the ratchet teeth 9 of the ratchet gear 7, and an operating lever 21 for operating the ratchet L. And a neutral return mechanism T for returning each of the ratchet L and the operation lever 21 to the neutral position.
Is a center return spring 25 formed in a torsion coil shape.
The spring return end 26 and the return spring end 27 at both ends are elastically locked to a spring locking portion 28 provided on an arbitrary fixed portion, respectively, and between the return spring end 26 and the return spring end 27. Is
A ratchet-type driving mechanism is provided in which the ratchet L or the engaging body 30 provided on the operation lever 21 is disposed to abut the return spring one end 26 and the return spring other end 27 to elastically deform the center return spring 25. According to the present invention, the center return spring 25 is provided in the axial direction of the engaging body 30.
The return spring one end 26 and the return spring other end 27 are arranged so as to be in parallel with the axis direction of It is a drive mechanism. According to the present invention, the ratchet gear 7 is axially mounted on the base plate 1 having the base plate 3 parallel to the ratchet gear 7 and a plurality of mounting arms 4 protruding in the axial direction of the ratchet gear 7 on the peripheral edge. The center return spring 25 is provided in the base plate 1 so as to be the same as the axial direction of the ratchet gear 7, and the center return spring 25
The return spring one end 26 and the return spring other end 27 at both ends are elastically engaged with spring engagement portions 28 formed on the left and right side surfaces of the mounting arm portion 4, respectively.
Is a ratchet type driving mechanism disposed between the return spring one end 26 and the return spring other end 27. In the present invention, the operation output shaft 6 is a ratchet-type drive mechanism in which a ratchet mounting member 10 provided with the ratchet L and an operation member 31 having the operation lever 21 are respectively mounted on the shaft.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Is a base plate attached to the seat-side fixing portion 2 of the vehicle seat. A plurality of mounting arms 4 are provided around the base plate 3 so as to protrude toward the seat-side fixing portion 2.
Are positioned at predetermined intervals in front and rear with respect to the seat-side fixing portion 2. In this case, in order to facilitate understanding, the positional relationship between the base plate 1 and the seat-side fixing portion 2 is referred to as front and rear, and the positional relationship is described as upper, lower, left, and right based on this reference, but the direction is not limited thereto. . An insertion hole 5 is provided at a center position of the base plate 3, and an operation output shaft 6 in the front-rear direction is inserted into the insertion hole 5. A ratchet gear 7 whose axis is in the front-rear direction is fixed to the operation output shaft 6 between the seat-side fixing portion 2 and the base plate 3. The ratchet gear 7 is formed to have ratchet teeth 9 on the outer periphery.

The operation output shaft 6 on the side opposite to the seat-side fixing portion 2 of the base plate 3 is provided with a ratchet mounting member 10 having a ratchet L. The ratchet mounting member 10 is formed of a vertically long plate member parallel to the base plate 3, has a mounting hole 11 at one end, and a front-rear direction ratchet mounting shaft 12 is mounted in the mounting hole 11. The ratchet mounting shaft 12 protruding toward the side fixing portion 2 is rotatably mounted with a portion where the bases of the one ratchet 13a and the other ratchet 13b are overlapped, and the one ratchet 13a and the other ratchet 13b are attached to the ratchet mounting shaft 12. Then, each tip engaging claw portion 14 is positioned on the left and right sides so as to form a “C” shape. That is, ratchet L
Has a ratchet 13a and a ratchet 13b, which are separate bodies, arranged in a "C" shape, and each of them independently engages with the ratchet gear 7 and rotates.
When the other ratchet 13b moves in the direction in which one engages the ratchet gear 7, the other ratchet 13b is formed in a shape that does not engage the ratchet gear 7, thereby preventing mechanical lock. On the other hand, the ratchet gear 7 side of the ratchet 13b is
Is formed on an arcuate surface 15 along the outer periphery of.

The guide shaft 1 whose axis is parallel to the operation output shaft 6 is provided between the base of the one ratchet 13a and the base of the other ratchet 13b and the tip engaging claw 14.
6 are provided, and each guide shaft 16 is connected to the ratchet mounting member 1.
0 is inserted into the guide hole 17 provided at the center. The guide hole 17 is formed as an elongated hole for guiding the movement of the guide shaft 16 when the ratchet mounting member 10 rotates about the operation output shaft 6. The one ratchet 13a and the other ratchet 13b
A spring 18 is provided between each of the guide shafts 16 to bias the two in a direction in which the two engage with the ratchet gear 7.
At the periphery of the base plate 3, a neutral bulging portion 20 bulging radially with respect to the axial direction is formed.
When the ratchet L is in the neutral position, the ratchet L comes into contact with the circular arc surface 15 to disengage the tip engaging claw portions 14 of the one ratchet 13a and the other ratchet 13b from the ratchet gear 7 about the center of the ratchet mounting shaft 12. This neutral bulge 20
When the stroke of the operation lever 21 is matched with the stroke length of the operation lever 21 to be described later, the arcuate surface 15 of the ratchet L, which is a non-operation target, is brought into contact with the neutral bulging portion 20 during the operation of the operation lever 21 so as to engage the tip. It is preferable that the claw portion 14 is separated from the ratchet gear 7.

A neutral return mechanism T is provided between the base plate 3 and the ratchet mounting member 10. The neutral return mechanism T is provided between the seat-side fixed portion 2 and the base plate 3 with a center return spring 25 having a configuration in which the axis is a torsion coil shape in the front-rear direction and receives a torsional moment around its axis to store bending elasticity. The return spring one end 26 and the return spring other end 27 of the center return spring 25 are configured to abut and lock the left and right side surfaces of the mounting arm 4 at positions shifted by 180 degrees with respect to the ratchet L. The left and right side surfaces of the mounting arm 4 serve as the spring locking portions 28. On the other hand, on the other end side of the ratchet mounting member 10, an engaging body 30 protruding toward the seat-side fixing portion 2 is provided.
When the ratchet mounting member 10 rotates, the engagement body 30 is brought into contact with one of the return spring one end 26 and the return spring other end 27 in the rotation direction and deformed. Then, when the operation force on the ratchet mounting member 10 is released, the elastic force of the center return spring 25 restores the elasticity until the spring comes into contact with the spring locking portion 28 and returns to the neutral position. In this case, when the base plate 3 of the base plate 1 is formed in a substantially circular shape in a front view, and a plurality of mounting arms 4 are provided on the periphery of the base plate 3, the center return spring 25 is located inside each mounting arm 4. The inside of each of the mounting arms 4 is preferable because it can also be expected to function as a guide for deformation of the center return spring 25 and a case for storing the center return spring 25.

An operating member 31 is provided on the front side of the ratchet mounting member 10. The operation member 31 is formed of a plate member parallel to the base plate 3, and a mounting hole 32 is formed at a position corresponding to the mounting hole 11 of the ratchet mounting member 10, and the ratchet mounting shaft 12 is fitted into the mounting hole 32. The operation lever 21 is provided at a desired position of the operation member 31. Therefore, when the operation lever 21 is operated, the ratchet mounting member 10 is rotated about the operation output shaft 6 via the ratchet mounting shaft 12. In this case, when the plurality of mounting arms 4 of the base plate 1 are provided so as to match the strokes of the operation lever 21 in both operation directions with the neutral position of the operation lever 21 interposed therebetween, the stopper 33 of the operation lever 21 is also used. A guide hole 34 is formed at a position corresponding to the guide hole 17 of the ratchet mounting member 10 of the operation member 31, and when the guide shaft 16 is fitted into each guide hole 34, the movement of the guide shaft 16 is guided. As a result, the operation is further smoothed, the interference between the operation member 31 and the guide shaft 16 is prevented, and errors in manufacturing and assembling accuracy can be absorbed by that amount, thereby facilitating manufacturing.

The operation output shaft 6 is connected to a seat lifter or a height mechanism via braking means or deceleration means, and the operation force from the operation lever 21 is transmitted from the operation output shaft 6 to each device. However, if the load applied to each device is not returned to the operation output shaft 6, the device becomes an operation device for various adjustment mechanisms of the vehicle seat. In this case, the brake force is transmitted from the operation output shaft 6, but the load from each device is stopped.
Is provided inside the center return spring 25, the space can be effectively used and the device can be downsized. When the cover member 36 is attached to the attachment arm 4 of the base plate 1 instead of the seat-side fixing portion 2, the cover member 36 and the operating member 3
It becomes a single assembly part (assembled state part) in a state of being sandwiched by 1, and improves workability in all operations, storage, and assembly.

FIG. 4 is a perspective view showing a disassembled state of the second embodiment, in which a brake case 35 is located between the base plate 1 and the seat-side fixing portion 2, and a center is provided on the outer periphery of the brake case 35. The return spring 25 is positioned. On the other hand, a bearing plate 37 corresponding to the base plate 1 is provided, the ratchet mounting member 10 and the ratchet gear 7 are provided between the base plate and the bearing plate 37, and the operation member 31 is provided outside the bearing plate 37.
The base plate 1 is sandwiched between the base plate 1 and the bearing plate 37 as the cover member 36 to form a single assembly part (assembled state part).
Workability has been improved in all of the assembly.

[0013]

Next, the operation will be described. The ratchet gear 7 is fixed to the operation output shaft 6 mounted on the base plate 1, and the ratchets L engaging with the ratchet gear 7 each have a tip engaging claw portion 14 at the tip and have a “C” shape. The bases of the one ratchet 13a and the other ratchet 13b are superimposed on each other and are rotatably mounted on the ratchet mounting member 10 by the ratchet mounting shaft 12. The ratchet mounting member 10 is mounted on the operation output shaft 6, and is opposite to the ratchet L. A return spring end 26 of a center return spring 25 is provided on the ratchet mounting member 10.
The engagement body 30 is located between the return spring end 27 and the return spring end 27 of the center return spring 25 when no operation is performed. It is in a neutral position.

In the neutral position, the ratchet mounting member 1
A radially projecting neutral bulging portion 20 is formed on the base plate 3 of the base plate 1 on the side of the 0 ratchet L, and the neutral bulging portion 20 has the respective circular arc surfaces of one ratchet 13a and the other ratchet 13b of the ratchet L. 15 are in contact with each other, so that one ratchet 13a and the other ratchet 13b
Is disengaged from the ratchet gear 7.
In this state, when the operation lever 21 is turned up or down, for example, downward, the operation member 31 rotates around the operation output shaft 6 and the ratchet mounting shaft 12 rotates counterclockwise in the figure. As a result, the arcuate surface 15 of the ratchet 13a remains in contact with the neutral bulging portion 20,
On the other hand, the tip engaging claw portion 14 of the ratchet 13a does not engage with the ratchet gear 7, and the tip engaging claw portion 14 of the ratchet 13b has the arcuate surface 15 disengaged from the neutral swelling portion 20. When the ratchet gear 7 is engaged with the ratchet teeth 9 of the gear 7 and the operation lever 21 is further pressed, the ratchet gear 7 is rotated counterclockwise.

When the operating lever 21 is pushed downward until it stops, the engaging member 30 of the ratchet mounting member 10
Is engaged with one end 26 of the return spring and rotates the center return spring 25. When the operator releases the operation lever 21 in this state, the center return spring 25 elastically returns to return the ratchet mounting member 10 to the neutral position. When the operation of the operation lever 21 is repeated downward from the neutral position, the ratchet 13b rotates the ratchet gear 7 counterclockwise. Thus, when the operation lever 21 is rotated to lift upward from the neutral position, the operation member 31 rotates around the operation output shaft 6 and the ratchet mounting shaft 12 rotates clockwise in the figure, As a result, since the arcuate surface 15 of the other ratchet 13b remains in contact with the neutral bulging portion 20, the tip engaging claw portion 14 of the other ratchet 13b separates from the ratchet gear 7 against the elasticity of the spring 18, On the other hand, the tip engaging claw portion 14 of the ratchet 13a engages with the ratchet gear 7 because the arcuate surface 15 is detached from the neutral bulging portion 20, and when the operating lever 21 is further pressed, the ratchet gear 7 rotates clockwise. Let it.

When the operating lever 21 is lifted upward until it stops, the engaging member 30 of the ratchet mounting member 10
Engages with the other end 27 of the return spring and rotates the center return spring 25. If the force is released from the operation lever 21 in this state, the center return spring 25 elastically returns to return the ratchet mounting member 10 to the neutral position. . In the above case, the operation of the operation lever 21 is performed by returning the center ratchet 13 to the first ratchet 13a and the other ratchet 1
3b is disengaged from the ratchet gear 7 by the action of the guide shaft 16 and the neutral bulging portion 20, so that when it is operated from the neutral position in either up or down direction, the ratchet gear 7 is moved in the operating direction. To rotate.

Therefore, regardless of the position of the ratchet gear 7 (adjustment state of the seat adjustment device), the operation lever 21 can be operated from the neutral position to either the upper or lower side regardless of the position. Is not only a single operation but also a repetitive operation that is performed continuously. Further, during continuous repetitive operation on one side, an operation for switching to the other side is also possible by simply returning to the neutral state once, and opposing operations can be performed by one operation lever 21, thereby improving operability. Thus, the ratchet mechanism includes a pair of one ratchet 13a and the other ratchet 1 each having a tip engaging claw portion 14 at the tip.
3b, the one ratchet 13a and the other ratchet 13b are rotatably mounted on the ratchet mounting member 10 by one ratchet mounting shaft 12 with their bases superimposed on each other. , Each of them independently rotates and operates reliably.

When one of the ratchets 13a and the other ratchet 13b move in a direction in which one engages with the ratchet gear 7, the other ratchet 13a and the other ratchet 13b are formed so as not to engage with the ratchet gear 7, thereby preventing mechanical lock. .
That is, the ratchet gear 7 side of the one ratchet 13a and the other ratchet 13b is formed on the arcuate surface 15 along the outer periphery of the ratchet gear 7, so that when one ratchet gear 7 is rotating, the other ratchet gear 7 And does not engage on the ratchet teeth 9 to prevent mechanical lock. In addition, in combination with the above-described configuration in which the one ratchet 13a and the other ratchet 13b are superposed on each other and are rotatably mounted by one ratchet mounting shaft 12, the mechanical lock is further prevented.

Further, the one ratchet 13a and the other ratchet 13b rotate independently of each other, so that the working space is small and the whole device is small. A guide shaft 16 parallel to the operation output shaft 6 is provided between the base of each of the ratchet 13a and the other ratchet 13b and the tip engaging claw 14 at the tip.
Is inserted into the guide hole 17 provided in the ratchet mounting member 10, thereby preventing the one ratchet 13a and the other ratchet 13b from rotating in opposite directions, thereby preventing mechanical lock. Further, since a spring 18 is provided between the guide shaft 16 of the one ratchet 13a and the guide shaft 16 of the other ratchet 13b, one spring 18 securely connects the two ratchets 13a and 13b to the ratchet gear 7. Is engaged.

A neutral bulging portion 20 bulging radially with respect to the axial direction is formed on the periphery of the base plate 3.
When the ratchet L is in the neutral position, the neutral swelling portion 20 is configured to abut on the arcuate surface 15, so that the spring 18 engages each of the one ratchet 13 a and the other ratchet 13 b with the ratchet gear 7. Even when biased, the arcuate surface 15 is brought into contact with the neutral bulging portion 20 to disengage the tip engaging claw portions 14 of the one ratchet 13a and the other ratchet 13b from the ratchet gear 7 about the center of the ratchet mounting shaft 12. To ensure that the neutral position is maintained. In this case, since the neutral bulging portion 20 matches the stroke length of the operation lever 21, the arc surface 15 of the other ratchet L is operated by the operation lever 21 while the other ratchet L is being operated. It is preferable that the vehicle rides on the protrusion 20 and is securely separated from the ratchet gear 7.

The center return spring 25 of the neutral return mechanism T is formed in a torsion coil shape having an axial center in the front-rear direction, and one end 26 and the other end 27 of the return spring at both ends are formed in the front-rear direction. The return spring end 2 is engaged with a spring locking portion 28 formed on the mounting arm portion 4 of the base plate 1.
6 and the return spring other end 27, the engaging body 30 of the ratchet mounting member 10 is positioned, so that when the ratchet mounting member 10 rotates, the engaging body 30 is always returned to the return spring one end 26.
And the center return spring 25 is deformed by contact with one of the other ends 27 of the return spring, so that the neutral return is ensured. In this case, the center return spring 25 is formed in a coil shape, the axial direction thereof is parallel to the axial direction of the engagement body 30, and the center return spring 25 is arranged so that the rotation direction coincides therewith. Since the other end 27 of the spring is configured so as to be in a direction crossing the rotation direction of the engagement body 30, the center return spring 25 is deformed inward and outward with respect to the rotation center of the engagement body 30. And make the device smaller. Also, the return spring one end 26 and the return spring other end 27 at both ends of the center return spring 25 are elastically locked to spring locking portions 28 formed on the left and right side surfaces of the mounting arm 4, respectively. The stoppers at both ends of the center return spring 25 are also used by the mounting arm 4 to reduce the number of parts and reduce the cost. Thus, an operation member 31 having an operation lever 21 is mounted on the operation output shaft 6 on which the ratchet mounting member 10 is mounted, and the operation member 31 is mounted by the ratchet mounting shaft 12 so as to rotate integrally with the ratchet mounting member 10. Therefore, when the ratchet mounting member 10 returns to the neutral position, the operation lever 21 also returns to the neutral position, and the neutral return mechanism T returns both the ratchet L and the operation lever 21 to the neutral position by one center return spring 25. This is a dual-purpose configuration.

Also, spring retaining portions 28 are formed on the left and right side surfaces of the mounting arm portion 4 formed on the base plate 1, and one end of the return spring 26 and the other end 27 of the return spring are engaged with the spring retaining portions 28. The assembling and assembling become easy, and the base plate 1 in this state can be transported, so that workability is extremely improved. In this case, the base plate 3 of the base plate 1 is formed in a substantially circular shape when viewed from the front, and when a plurality of mounting arms 4 are provided on the periphery thereof, a center return spring 25 is brought into contact with the inner circumference of each mounting arm 4 to guide. In other words, the center return spring 25 can be preferably used as a storage case. Further, since the center return spring 25 is formed in the shape of a torsion coil with its axial center in the front-rear direction, a small storage space is required, and the entire apparatus is downsized. In this case, the brake force is transmitted from the operation output shaft 6 but the load from each device is stopped.
It is preferable that the center return spring 25 be provided inside the center return spring 25, because the space can be effectively used and the device can be reduced in size. Also,
When the cover member 36 is mounted on the mounting arm 4 of the base plate 1 instead of the seat-side fixing portion 2, the cover member 36
It is suitable because it becomes a single assembly part (assembled state part) in a state of being sandwiched by the operation member 31 and improves workability in all of work, storage, and assembly. Note that the second embodiment has the same effect.

[0023]

The present invention provides a ratchet gear 7 having ratchet teeth 9 on its outer periphery, a ratchet L engaging with the ratchet teeth 9 of the ratchet gear 7, an operation lever 21 for operating the ratchet L, and a ratchet L. Operation lever 2
1 having a neutral return mechanism T for returning each of them to a neutral position, the neutral return mechanism T includes a return spring end 26 and a return spring other end 27 at both ends of a center return spring 25 formed in a torsion coil shape. Each of the return spring ends 26 is elastically engaged with a spring engagement portion 28 provided on an arbitrary fixed portion.
The ratchet L or the operating lever 21 that elastically deforms the center return spring 25 by contacting the return spring one end 26 and the return spring other end 27 between
Since the ratchet-type drive mechanism in which the engaging members 30 provided in the above-described embodiments are arranged is used, a small storage space is required, and the entire apparatus is downsized. According to the present invention, the center return spring 25 is arranged so that its axial direction is parallel to the axial direction of the engagement body 30 so that the rotation direction coincides with the center return spring 25. Since the ratchet drive mechanism is configured to be in a direction crossing the rotation direction of the united body 30, the center return spring 25 is deformed inward and outward with respect to the rotation center of the engagement body 30. And make the device smaller.
In the present invention, the ratchet gear 7 is
Base plate 1 provided with a plurality of mounting arms 4 protruding in the axial direction of a ratchet gear 7 on the peripheral edge of the base plate 3 and the peripheral edge thereof.
And the center return spring 2
5 is provided in the base plate 1 so as to be the same as the axial direction of the ratchet gear 7, and one end 26 and the other end 27 of the return spring at both ends of the center return spring 25 are provided on the left and right side surfaces of the mounting arm 4. A ratchet-type drive in which the ratchet L or the engaging body 30 provided on the operation lever 21 is elastically locked to the formed spring locking portions 28, respectively, and is disposed between the return spring one end 26 and the return spring other end 27. Since the mechanism is a mechanism, the stoppers at both ends of the center return spring 25 are also used by the mounting arms 4 of the base plate 1 to reduce the number of parts and reduce the cost. In the present invention, the operation output shaft 6 is a ratchet-type drive mechanism in which the ratchet mounting member 10 provided with the ratchet L and the operation member 31 having the operation lever 21 are respectively mounted on a shaft. When the lever 10 returns to the neutral position, the operating lever 21 also returns to the neutral position,
The neutral return mechanism T is configured so that both the ratchet L and the operation lever 21 return to neutral by one center return spring 25.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view.

FIG. 2 is a side view of a neutral position.

FIG. 3 is an operation state explanatory side view.

FIG. 4 is an exploded perspective view of another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base plate, 2 ... Seat side fixed part, 3 ... Base plate, 4 ... Mounting arm part, 5 ... Insertion hole, 6 ... Operation output shaft, 7 ...
Ratchet gear, 9: ratchet teeth, 10: ratchet mounting member, 11: mounting hole, 12: ratchet mounting shaft, 1
3a: one ratchet, 13b: another ratchet, 14
... Tip engaging claw portion, 15... Arc surface, 16... Guide shaft, 17
... Guide holes, 18 ... Springs, 20 ... Neutral bulges, 21 ...
Operation lever, 25 ... Center return spring, 26 ... One end of return spring, 27 ... Other end of return spring, 28 ... Spring locking part, 30 ...
Engagement body, 31 operating member, 32 mounting hole, 33 stopper, 34 guide hole, 35 brake case, 36
Cover member.

Claims (4)

[Claims] 1. A ratchet gear 7 having ratchet teeth 9 on its outer periphery, a ratchet L engaging with the ratchet teeth 9 of the ratchet gear 7, an operation lever 21 for operating the ratchet L, and the ratchet L and the operation lever. 21 having a neutral return mechanism T for returning each of them to a neutral position, wherein the neutral return mechanism T includes a return spring end 26 at both ends of a center return spring 25 formed in a torsion coil shape.
And the other end 27 of the return spring are elastically engaged with a spring engagement portion 28 provided on an arbitrary fixed portion, respectively. And a ratchet-type driving mechanism in which the ratchet L or the engagement body 30 provided on the operation lever 21 is disposed to abut the other end 27 of the return spring to elastically deform the center return spring 25. 2. The center return spring 25 according to claim 1, wherein the center return spring 25 is arranged in such a manner that its axial direction is parallel to the axial direction of the engagement body 30 so that the rotation direction coincides therewith. The other end 27 is a ratchet-type drive mechanism configured to be in a direction crossing the rotation direction of the engagement body 30. 3. The base plate according to claim 1, wherein the ratchet gear 7 is provided with a base plate 3 parallel to the ratchet gear 7 and a plurality of mounting arms 4 protruding in the axial direction of the ratchet gear 7 around the periphery. Operation output shaft 6 in 1
The center return spring 25 is provided in the base plate 1 so as to be the same as the axial direction of the ratchet gear 7. The return spring end 26 and the return spring end 27 at both ends of the center return spring 25 are The mounting arm 4
The latches L or the operating members 21 provided on the operation lever 21 are elastically locked respectively on spring locking portions 28 formed on the left and right side surfaces, and the return spring one end 26 and the return spring other end 27
Ratchet-type drive mechanism located between. 4. A ratchet-type drive mechanism according to claim 3, wherein the operation output shaft 6 is provided with a ratchet mounting member 10 provided with the ratchet L and an operation member 31 having the operation lever 21.