JPH11264267A - Steering locking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent illegal lock release while avoiding breaking generated at the time of unjust lock release operation in a steering locking device in need of operation of pushing a rotor into a cylinder body at the time of rotating operation of the rotor from an ACC position to a lock position. SOLUTION: A plurality of tumblers 28 that can be engaged with a rotating cylinder 15 inserted between a rotor 14 and a cylinder body 12 are mounted to the rotor 14 in such a way as to be able to release the engagement of all the tumblers 28 with the rotating cylinder 15 only when a normal key 13 is inserted. A cam face 38 moving a joint 16 from an advance position to a retreat position through each pressing member 36 at the time of rotation from the lock position of the rotating cylinder 15 in the state of being connected to the rotor 14, to an ACC position is provided at the rear part of the rotating cylinder 15. The rotor 14 and the joint 16 are connected in the advance position of the joint 16, and connection between the rotor 14 and the joint 16 is released in the retreat position of the joint 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering lock device and, more particularly, to a fixed cylinder body and a key which is inserted into the cylinder body so that the key can be inserted and the key can be rotated by the inserted key. A rotor, a joint that can rotate in accordance with the rotor, and a steering shaft that is locked together with the rotor so that the steering shaft cannot rotate in response to the rotation of the joint to the LOCK position. And a lock member that is positioned from the ACC position of the rotor.
The present invention relates to a steering lock device that requires an operation of pushing the rotor together with the key into the cylinder body during the rotation operation to the K position.

[0002]

2. Description of the Related Art Conventionally, a LOCK position is set from an ACC position of a rotor.
A steering lock device that requires a pushing operation when rotating to a position is already known, for example, from Japanese Utility Model Publication No. 7-5002, and in such a steering lock device, a rotor is rotated from an ACC position to a LOCK position. In doing so, the pushing operation is forced to prevent the rotor from rotating at a stretch, thereby enhancing the safety during running of the vehicle.

[0003]

In such a steering lock device, it is necessary to prevent unauthorized unlocking of the rotor due to the fact that something other than a regular key is inserted into the rotor. A structure in which the fuse portion (cut portion) provided in the rotor is cut off in response to the forcible rotation and power is not transmitted from the rotor to the joint has already been realized.

However, if the rotor is cut as described above, the rotor will be destroyed after the unauthorized unlocking operation is performed, so the steering lock device needs to be replaced.

[0005] The present invention has been made in view of the above circumstances, and avoids the occurrence of destruction at the time of an unauthorized unlocking operation, eliminates the need for replacement, and prevents the unauthorized unlocking. It is an object to provide a locking device.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fixed cylinder body, a key body, and a key body. A rotor to be inserted, a joint that can rotate following the rotor, and a joint that enables the steering shaft to be locked in a non-rotatable manner as the joint rotates with the rotor to the LOCK position. An interlocking and coupled lock member, wherein a steering lock device which requires an operation of pushing the rotor together with the key into the cylinder when the rotor is rotated from the ACC position to the LOCK position; When the rotor is at a position other than the ACC, the cylinder is inserted into and fixed to the front part. The rotation cylinder is inserted between the rotor and the cylinder body while being restricted from moving in the axial direction, and is inserted between the rotor and the cylinder body. A plurality of tumblers that can be engaged with the moving cylinder are mounted so that the tumblers can be disengaged from all the rotating cylinders only when a regular key is inserted, and the tumbler is in a forward position close to the cylinder body. The cylinder is configured to be movable between a retracted position separated from the cylinder body and a spring biased to a forward position to be able to rotate about the same axis as a rotation axis of the rotor. The rear ends of the plurality of pressing members housed in the housing on the rear side of the body and capable of moving in a direction parallel to the rotation axis of the rotor abut against the front end of the joint. At the rear of the rotary cylinder, the joint is provided via each of the pressing members in accordance with the rotation of the rotary cylinder from the LOCK position to the ACC position in a state where the rotary cylinder is connected to the rotor via the tumbler. A cam surface for moving from a forward position to a retracted position is provided so as to contact a front end of each pressing member, and an engaging portion extending toward a joint is integrally provided at a rear end of the rotor, and the joint is moved forward. A locking recess for inserting the engaging portion in the position is provided at a front portion of the joint so as to disengage the engaging portion in response to movement of the joint to a retracted position. When the engaging portion is inserted into the locking concave portion, the LOCK position of the rotor and A
Although the rotor is allowed to idle by a predetermined angle when rotating between the CC positions, it is formed into a shape in which the engaging portion is engaged so as to be relatively non-rotatable when the rotor rotates between the LOCK position and the ACC position. It is characterized by being formed.

According to this configuration, when a regular key is inserted into the rotor, all of the plurality of tumblers mounted on the rotor do not engage with the rotating cylinder, and the rotating cylinder is not rotated. The rotor can be turned to the right and the joint is also in the forward position. Therefore, the engaging portion integrated with the rotor is inserted into the locking concave portion of the joint, and the rotor and the joint are connected while the rotor idles by a predetermined angle when the rotor rotates between the LOCK position and the ACC position. The joint turns in response to the turning operation of the rotor by a proper key. on the other hand,
If anything other than a regular key is inserted into the rotor, all engagement of the tumbler with the rotating cylinder is not released. The moving cylinder also rotates with the rotor. For this reason, when the rotor rotates from the LOCK position to the ACC position, each pressing member moves the joint to the retracted position, the engaging portion integral with the rotor is disengaged from the locking recess of the joint, and the joint rotates. Since the rotor idles without squeezing, the locked state of the steering shaft by the lock member is not released, and unauthorized unlocking can be prevented. Moreover, even if the rotor is pushed in the ACC position, the rotor rotates idly by a predetermined angle from the LOCK position to the ACC position, so that the engaging portion of the rotor is not inserted into the locking recess of the joint, and And the connection of joints is not possible. Therefore, unauthorized unlocking can be prevented without destroying each component constituting the steering lock device,
After the unauthorized unlocking operation, the steering lock device can be used without replacement.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIGS. 1 to 9 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a steering lock device when a rotor is at an ACC position with a proper key inserted. 2 is a perspective view of the cylinder body as viewed obliquely from the front side, FIG. 3 is a side view of the rotating cylinder, FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1, and FIG. FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 1, and FIG.
FIG. 8 is a sectional view taken along line -8 in FIG.
FIG. 9 is a sectional view taken along a line, and FIG. 1 shows a state where an irregular key is inserted.
It is a longitudinal sectional view corresponding to FIG.

First, in FIG. 1, the steering lock device includes a housing 11 attached to a steering column (not shown), and a housing 11 inserted into a front portion of the housing 11.
A fixed cylinder body 12, a rotor 14 inserted into the cylinder body 12 by enabling a rotation operation with a regular key 13 inserted therein, and a rear portion of the rotor 14 and a cylinder A rotary cylinder 15 inserted between the bodies 12, a joint 16 that can be relatively non-rotatably engaged with the rotor 14, and a joint 16 that enables a steering shaft (not shown) to be locked non-rotatably. A lock member 17 (see FIG. 8), which is linked to and connected to the joint 11, and an ignition switch 18 connected to the joint 16 and attached to the rear end of the housing 11.

The housing 11 is provided with a storage hole 20 whose front end is open.
A cylinder body 12 formed into a bottomed cylindrical shape with a closed rear end is inserted, and a regulating pin 21 inserted into the housing 11 from the outside thereof is inserted into and engaged with the cylinder body 12, whereby the cylinder body 12 is fixed to the front part in the housing 11.

Referring also to FIG. 2, a front end of the cylinder body 12 has a first cam surface 22 as an annular step facing forward.
Is formed to provide the enlarged diameter hole portion 23. The LOCK position, the ACC position, the ON position, and the START position are displayed on the front end face of the cylinder body 12 at intervals in the circumferential direction.

On the other hand, the rotor 14 is formed in a rod shape having a circular cross section with a bottomed key hole 25 having an open front end, and is rotatable in a cylinder hole 26 provided in the cylinder body 12. Inserted. At the front end of the rotor 14, a flange portion 14a inserted into the enlarged diameter hole portion 23 facing the first cam surface 22 at the front portion of the cylinder body 12 is integrally provided so as to project radially outward. A protrusion 24 slidingly in contact with the first cam surface 22 is integrally provided at one position along the circumferential direction of the flange portion 14a.

The first cam surface 22 has a first flat portion 22a formed in an arc shape along a plane perpendicular to the rotation axis of the rotor 14, and a rear surface of the rotor 14 with respect to the first flat portion 22a. A second flat portion 22b which is formed in an arc shape along a plane perpendicular to the rotation axis and is continuous with one end in the circumferential direction of the first flat portion 22a, and the other end in the circumferential direction of the first flat portion 22a; And an inclined portion 22c that smoothly connects the second flat portions 22b. The protrusion 24 of the rotor 14 slides along the first cam surface 22. When the rotor 14 rotates from the ACC position to the LOCK position, the protrusion 24 moves to the first position. The rotor 14 can be pushed from one end of the flat portion 22a to the second flat portion 22b, and the rotor 14 is locked from the ACC position.
As the position moves, the protruding portion 24 becomes the second flat portion 22.
b to the other end of the first flat portion 22a through the inclined portion 22c, so that the rotor 14 pushed in at the ACC position is locked.
The position will automatically return to the original position.

Referring also to FIG. 3, a rotary cylinder 15 capable of rotating relative to the rotor 14 is inserted between the rear portion of the rotor 14 and the cylinder body 12. This rotating cylinder 15
A large-diameter cylindrical portion 15a that slides the outer peripheral surface on the inner peripheral surface of the cylinder hole 26 and slidably contacts the outer peripheral surface of the rotor 14 on the inner peripheral surface, and a step between the rear end of the large-diameter cylindrical portion 15a. And a small-diameter cylindrical portion 15b for slidingly contacting the outer peripheral surface of the rotor 14 with the inner peripheral surface is provided coaxially and integrally with the small-diameter cylindrical portion 15b.
2, the inner end of the regulating pin 21 is engaged with an annular step 27 provided on the outer periphery of the front end of the large-diameter cylindrical portion 15a. Therefore, the rotating cylinder 15 is inserted between the rotor 14 and the cylinder body 12 while being allowed to rotate relative to the rotor 14 while the axial position is regulated between the rear end closing portion of the cylinder body 12 and the regulating pin 21. Will be.

Referring also to FIG. 4, the rotor 14 includes
A plurality of pairs of tumblers 28 are mounted at a plurality of locations spaced apart in the axial direction of the rotor 14 so that one end of the tumblers 28 can be projected from the outer surface of the rotor 14. Springs 29 are provided between the rotors 14, respectively. On the other hand, concave portions 30 are provided on the inner surface of the large-diameter cylindrical portion 15a of the rotary cylinder 15 at portions corresponding to both ends of each tumbler 28. 30... Each tumbler 28 is provided with a regular key 13 to the key hole 25.
When the tumbler 28 is inserted, all of the tumblers 28 are disengaged from the recesses 30..., But the key hole 25 is replaced with a key other than the regular key 13, for example, as shown in FIG. When at least one of the tumblers 28 is inserted, at least one of the tumblers 28 engages with the recess 30 at one end in the axial direction. Therefore, when the regular key 13 is inserted into the key hole 25, the rotating cylinder 15 does not rotate together with the rotor 14, but the rotor 14 is turned by inserting something other than the regular key 13 into the key hole 25. When the moving operation is performed, the rotating cylinder 15 rotates together with the rotor 14.

At the rear side of the cylinder body 12, the housing 11
Inside, a joint 16 capable of rotating about the same axis as the rotation axis of the rotor 14 is provided at an advanced position close to the cylinder body 12 and the cylinder body 12.
The joint 16 is housed so as to be movable between the retracted positions separated from the housing 11, and the joint 16 is spring-biased toward the forward position by a spring 31 interposed between the joint 16 and the housing 11.

At the rear side of the cylinder body 12, the housing 11
An annular step portion 32 facing the cylinder body 12 is provided on the inner surface of the joint 16. At a front end of the joint 16, a flange 16 a facing the step portion 32 projects radially outward. A spring 31, which is provided integrally and biases the joint 16 toward the forward position, is provided between the step portion 32 and the flange portion 16a.

6 and 7, an annular second cam surface 34 is provided on the outer peripheral portion of the front end surface of the joint 16, that is, on the outer peripheral portion of the front surface of the flange portion 16a. Reference numeral 34 denotes a peak 34a which is inclined from the intermediate portion between the LOCK position and the ACC position toward the ACC position toward the cylinder body 12 side, and one end of the peak 34a is connected to the peak 34a at the ACC position with a step. With L
The crest 34 is located at an intermediate portion between the OCK position and the ACC position.
The flat portion 34b is formed so as to extend along a plane orthogonal to the rotation axis of the joint 16 with the arc-shaped flat portion 34b having the other end continuing to the inclination start point a.

On the other hand, a control pin 35 for sliding the inner end of the housing 11 into contact with the second cam surface 34 is press-fitted into the housing 11. Therefore, the rotor 14 and the joint 1
When the rotor 14 is rotated from the ACC position to the LOCK position in a state in which the rotor 6 is connected, the rotor 14 and the joint 16 must be pushed in so that the control pin 35 does not climb over the peak 34a.
Cannot be turned from the ACC position to the LOCK position.

At the front end of the joint 16 on the inner side of the second cam surface 34, a plurality of, for example, a pair of pin-shaped pressing members 36, which can move in a direction parallel to the rotation axis of the rotor 14, The rear end of 36 is abutted. These pressing members 36, 36 are arranged on one diameter line of the joint 16, and a pair of sliding holes through which the pressing members 36, 36 are slidably inserted are formed in the rear end closing portion of the cylinder body 12. 37, 37 are provided.

The tip of each of the pressing members 36, 36 is
5 is slidably contacted with a third cam surface 38 provided at the rear of the fifth cam 5. The third cam surface 38 is formed at a step between the large-diameter cylindrical portion 15a and the small-diameter cylindrical portion 15b in the rotary cylinder 15, and the pressing members 36, 36 when the rotor 14 is at the LOCK position. Are formed into a triangular shape so that the front ends of the
4 are formed on a flat surface along a plane orthogonal to the rotation axis of the pair 4 and connect a pair of flat portions 38b to each other.

According to the third cam surface 38, the rotary cylinder 15 is connected to the rotor 14 via the tumbler 28 in response to the insertion of a key other than the regular key 13 into the rotor 14.
And the rotating cylinder 15 together with the rotor 14
When rotating from the OCK position to the ACC position, as shown by the chain line in FIG. 3, the front ends of the pressing members 36, 36 ride on the flat portions 38b from the concave portions 38a, so that the pressing members 36, 36 The joint 16 is moved from the advanced position to the retracted position against the spring force of the spring 32.

At the center of the rear end of the rotor 14, an engaging portion 40 having, for example, a substantially T-shaped cross section is provided integrally, and the engaging portion 40 closes the rear end of the cylinder body 12. The central portion of the portion is axially movable and pivotable, and extends through the joint 16 side. Thus, the engaging portion 40 is provided with a retaining ring 39 for preventing the rotor 14 from moving forward in the direction of coming out of the cylinder body 12 by coming into contact with the rear surface of the rear end closing portion of the cylinder body 12. You.

On the other hand, at the front of the joint 16, a locking recess 41 for inserting the engaging portion 40 when the joint 16 is at the forward position is engaged with the engaging portion 40 in accordance with the movement of the joint 16 to the retracted position. The locking recess 41 is provided so as to disengage the portion 40.
When the engaging portion 40 is inserted into the
From the K position (the position shown by the chain line in FIG. 6) to the ACC position (FIG.
(A position shown by a solid line in FIG. 3), a play is allowed between the engaging portion 40 and the rotor 14 to allow the rotor 14 to idle by a predetermined angle, and the LOCK position and AC
At the time of rotation of the rotor 14 other than between the C positions, the engagement portion 40 is formed so as to be engaged so as not to rotate relatively.

By the way, when the rotor 14 rotates from the LOCK position to the ACC position, the operation of the second cam surface 34 and the control pin 35 causes the control pin 35 to climb over the peak 34a of the second cam surface 34. Although the joint 16 is pushed rearward, the height of the peak portion 34a on the second cam surface 34 is set so that the engaging portion 40 does not come off from the locking concave portion 41 at that time.

In FIG. 8, a slider 45 having a through hole 44 through which a cam 43 provided in the joint 16 is inserted is slidably fitted to the rear portion of the housing 11, and engages with a steering shaft to engage the steering shaft. A lock member 17 for locking the shaft so that it cannot rotate is connected to the slider 45, and a spring 46 for urging the slider 45 in a direction in which the lock member 17 locks the steering shaft is fixed between the cap 47 and the slider 45. Is provided.

When the rotor 14 is in a position other than the LOCK position, that is, in the ACC position, the ON position, and the START position, the lock member 17 is in a state in which the steering shaft is allowed to rotate.
Is in the LOCK position, the cam 43 is in a rotational position such that the slider 45 is moved by the spring force of the spring 46 so that the lock member 17 is engaged with the steering shaft.

Next, the operation of this embodiment will be described. The rotating cylinder 15 which can rotate relative to the rotor 14 is restricted from moving in the axial direction, and the rotor 14 and the cylinder body 1 are controlled.
A plurality of tumblers 28 which are inserted between the rotors 2 and are spring-biased in a direction of engaging with the rotating cylinder 15 are provided only when the regular key 13 is inserted.
.. Are disengaged from all of the rotating cylinders 15. Therefore, when the regular key 13 is inserted into the rotor 14 as shown in FIG. 1, all the tumblers 28 are disengaged from the rotating cylinder 15 as shown in FIG. The rotor 14 can be rotated without rotating the. On the other hand, FIG.
When a key other than the regular key 13, for example, an irregular key 13 ′ is inserted into the rotor 14, at least a part of each tumbler 28 is engaged with the rotating cylinder 15 as shown in FIG. Key 1
When the rotor 14 is forcibly rotated at 3 ', the rotating cylinder 15 also rotates together with the rotor 14.

Furthermore, the joint 16 is connected to the cylinder 12
Is moved between a forward position close to the cylinder body and a retracted position separated from the cylinder body 12, and is spring-biased toward the forward position to be housed in the housing 11 on the rear side of the cylinder body 12. And a plurality of, for example, a pair of pressing members 36 provided between the joints 16,
The front end of the rotating cylinder 15 is in sliding contact with a third cam surface 38 provided at the rear portion of the rotating cylinder 15.
The joint 16 is moved from the forward position to the retracted position via the pressing members 36 in accordance with the rotation from the LOCK position to the ACC position. Therefore, when the rotor 14 is rotated by the irregular key 13 ', the pressing members 36, 36 move the joint 16 to the retracted position in accordance with the rotation of the rotary cylinder 15.

Moreover, the engaging portion 4 provided integrally with the rotor 14
0 is provided at the front of the joint 16 so that the engaging concave portion 41 for inserting the joint 16 at the forward position is disengaged from the engaging portion 40 in accordance with the movement of the joint 16 to the retracted position. This locking recess 41
Allows the rotor 14 to rotate idly by a predetermined angle when the rotor 14 rotates between the LOCK position and the ACC position when the engaging portion 40 is inserted into the locking concave portion 41. However, the LOCK position and the ACC When the rotor 14 is rotated between positions other than the positions, the engagement portion 40 is formed so as to be engaged so as not to rotate relatively. Therefore, the regular key 1
3, when the rotor 14 rotates, the LOC of the rotor 14
Although the rotor 14 idles by a predetermined angle when rotating between the K position and the ACC position, the rotor 14 and the joint 16 are in a connected state, and the joint 16 is rotated in accordance with the rotating operation of the rotor 14 by the regular key 13. Will do. On the other hand, when the rotor 14 is forcibly rotated by the irregular key 13 ', the pressing members 36, 3 are turned on in accordance with the rotation of the rotor 14 from the LOCK position to the ACC position.
6 moves the joint 16 to the retracted position,
Will be disengaged from the locking recess 41, and the rotor 14 will idle, so that the locked state of the steering shaft by the lock member 17 will not be released, and unauthorized unlocking can be prevented.

Further, even if the rotor 14 is pushed in the ACC position, the rotor 14 rotates idle by a predetermined angle from the LOCK position to the ACC position.
Is not inserted into the locking recess 41 of the joint 16, and the connection between the rotor 14 and the joint 16 is impossible.

In this way, unauthorized unlocking can be prevented without destroying the components constituting the steering lock device, and the steering lock device can be used without replacement after the unauthorized unlocking operation.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0035]

As described above, according to the present invention, when something other than a regular key is inserted into the rotor, the connection between the rotor and the joint is released in accordance with the rotation of the rotor, and the rotor is made to idle. In addition, unauthorized unlocking can be prevented without destroying each component constituting the steering lock device, and the steering lock device can be used as it is without replacement after the unauthorized unlocking operation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a steering lock device when a rotor is at an ACC position with a proper key inserted.

FIG. 2 is a perspective view of the cylinder body as viewed obliquely from the front side.

FIG. 3 is a side view of a rotating cylinder.

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a sectional view corresponding to FIG. 4 when an unauthorized key is inserted.

FIG. 6 is an enlarged sectional view taken along line 6-6 of FIG. 1;

FIG. 7 is a circumferential development sectional view taken along line 7-7 in FIG. 6;

FIG. 8 is a sectional view taken along line 8-8 of FIG. 1;

FIG. 9 is a longitudinal sectional view corresponding to FIG. 1 in a state where an irregular key is inserted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Housing 12 ... Cylinder body 13 ... Key 14 ... Rotor 15 ... Rotating cylinder 16 ... Joint 17 ... Lock member 28 ... Tumbler 36 ... Pressing member 38 cam surface 40 engagement part 41 locking recess

Claims (1)

[Claims] A fixed cylinder body (12) and a key (1)
3) a rotor (14) inserted into the cylinder body (12) to enable insertion of the key (13) and to be rotatable by the inserted key (13);
4) The joint (16) which can be rotated by following and the joint (16) together with the rotor (14)
The joint (1) enables the steering shaft to be locked so as not to rotate in response to the rotation to the CK position.
6) a lock member (17) interlocked with and connected to
A fixed housing for a steering lock device which requires an operation of pushing the rotor (14) together with the key (13) into the cylinder body (12) when the rotor (14) is turned from the ACC position to the LOCK position. The rotor (14) is inserted into the cylinder (12) which is inserted and fixed to the front part inside the (11) so that the rotor (14) cannot be pushed into the cylinder (12) at a position other than its ACC, A rotation cylinder (15) that is capable of relative rotation with (14) is inserted between the rotor (14) and the cylinder body (12) while being restricted from moving in the axial direction,
The rotor (14) has a plurality of tumblers (28) that can be engaged with the rotating cylinder (15) only when the regular key (13) is inserted. 15) is mounted so as to be disengageable from the cylinder body (12), and enables movement between a forward position close to the cylinder body (12) and a retracted position away from the cylinder body (12), and a forward position. The joint (16), which is spring-biased to the side, is able to rotate about the same axis as the rotation axis of the rotor (14), so that the joint (16) is located in the housing (11) behind the cylinder body (12). The rear ends of the plurality of pressing members (36) that are stored and can move in a direction parallel to the rotation axis of the rotor (14) are brought into contact with the front ends of the joints (16), and the rotation is performed. Rear part of tube (15) Is the pivoting cylinder in a state of being connected to the rotor (14) through said tumbler (28) (1
5) the joint (16) through each of the pressing members (36) in response to the rotation from the LOCK position to the ACC position in (5).
(38) for moving the cam from the forward position to the reverse position
Are provided so that the front ends of the pressing members (36) come into contact with each other, and an engaging portion (40) extending toward the joint (16) is integrally provided at the rear end of the rotor (14).
When the joint (16) is in the forward position, the engaging recess (41) for inserting the engaging portion (40) is moved in accordance with the movement of the joint (16) to the retracted position. The engaging recess (41) is provided at the front of the joint (16) such that the engaging portion (40) is inserted into the engaging recess (41). While the rotor (14) is allowed to idle by a predetermined angle when rotating between the LOCK position and the ACC position, the engaging portion (40) is rotated when the rotor (14) rotates between a position other than the LOCK position and the ACC position. ) Is formed in such a shape as to engage relative rotation impossible.