Angle adjustment apparatus for vehicle seat

1. Field of the Invention

The present invention relates to an angle adjustment apparatus for a vehicle seat, the apparatus angle-adjustably connecting a first seat member and a second seat member of the vehicle seat.

2. Description of Related Art

An angle adjustment apparatus is a recliner that angle-adjustably connects a seat back to a seat cushion, for example (refer to the specification of U.S. Pat. No. 5,516,198). A conventional recliner has an arm plate provided to a seat back, a base plate provided to a seat cushion, a slider axially movably provided between the arm plate and the base plate, and a movement mechanism axially moving the slider relative to the arm plate.

The arm plate has teeth on a surface facing the slider. The slider has a tubular main body and a flange provided to an end portion of the main body. The flange is provided with teeth on a surface facing the arm plate, the teeth being engaged with the teeth of the arm plate. The movement mechanism has a tubular slider guide to which the slider main body is inserted, and a lever connected to the slider guide. The slider guide is provided with a guide hole extending obliquely in axial and circumferential directions. A pin is inserted to the guide hole, and an end portion of the pin is attached to the slider.

Thus, when the slider guide is axially rotated by the lever, the pin is axially moved along the guide hole of the slider guide. The slider is axially moved concurrently with the pin, and then the teeth of the slider are disengaged from the teeth provided to the arm plate. Thereby, the arm plate is axially rotatable relative to the base plate. When the lever is returned to an original position, the teeth provided to the slider and the teeth provided to the arm plate are engaged again. Thus, the arm plate is regulated from being rotated relative to the base plate.

The lever is provided, however, to an external peripheral surface of the slider guide, and the slider is provided to an internal peripheral side of the slider guide. The slider has the end portion axially extending more than the slider guide, and the flange projecting radially externally from the end portion more than the slider guide. The flange is provided with the teeth. Thus, an input torque is transferred from the radially external side to internal side, when the torque is transferred from the lever to the slider. The teeth of the slider are positioned radially externally in order to obtain the torque. Thus, the conventional angle adjustment apparatus has a complex configuration having radially crossing members.

In view of the above, the present invention provides an angle adjustment apparatus for a vehicle seat. A first advantage of the embodiments of the present invention provides an angle adjustment apparatus for a vehicle seat including a first member attached to a first seat member; a second member attached to a second seat member and rotatably mounted to the first member; a lock member axially movably provided between the first member and the second member; and a movement mechanism axially moving the lock member relative to the first member. The first member has first teeth on a surface facing the lock member. The lock member has second teeth and a rotation regulation portion, the second teeth being engaged with the first teeth at a position radially external to the rotation center of the first member and the second member, the rotation regulation portion being engaged with the second member and regulating the lock member from being axially rotated relative to the second member. The movement mechanism has an input member and a drive member, the input member being provided at the rotation center of the first member and the second member, and being regulated from being axially moved relative to one of the first member and the second member, the drive member being provided between an external peripheral surface of the input member and the lock member, and being regulated from being axially moved relative to the lock member. A first engagement portion is provided to the external peripheral surface of the input member. A second engagement portion engaged with the first engagement portion is provided to the drive member. At least one of the first engagement portion and the second engagement portion is provided extending axially and circumferentially.

Accordingly, when the input member is axially rotated, the drive member is axially moved by the first engagement portion and the second engagement portion, relative to the input member. The drive member is positioned radially external to the input member. The lock member, which is positioned radially external to the drive member, is axially moved by the drive member. Thus, an input torque is transferred from the radial center to the external side. The lock member has the second teeth engaged with the first teeth of the first member at a position radially external to the drive member. Thus, the lock member and the first member are mutually engaged with a relatively large torque. Thereby, the members are radially aligned without having radially crossing portions, and the lock member and the first member are engaged with a large torque. Accordingly, the angle adjustment apparatus can be constructed simply, compared to a conventional configuration.

The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

FIG. 1 is a perspective view of a vehicle seat;

FIG. 2 is a perspective view of an angle adjustment apparatus;

FIG. 3 is an exploded perspective view of the angle adjustment apparatus;

FIG. 4 is an exploded perspective view of the angle adjustment apparatus;

FIG. 5 is a cross-sectional fragmentary view of the angle adjustment apparatus in a locked state taken along line V-V of FIG. 2 ;

FIG. 6 is a cross-sectional fragmentary view of the angle adjustment apparatus in an unlocked state taken along line V-V of FIG. 2 ;

FIG. 7 is an exploded perspective view of an angle adjustment apparatus according to an alternative embodiment;

FIG. 8 is an exploded perspective view of the angle adjustment apparatus according to the alternative embodiment;

FIG. 9 is a cross-sectional view of the angle adjustment apparatus according to the alternative embodiment; and

FIG. 10 is a partially enlarged perspective view of a first member according to the alternative embodiment.

The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description is taken with the drawings making apparent to those skilled in the art how the forms of the present invention may be embodied in practice.

An embodiment of the present invention is explained with reference to FIGS. 1 to 6 . As shown in FIG. 1 , a vehicle seat 10 is a seat mounted to a vehicle and the like. The vehicle seat 10 has a seat back 11 , a seat cushion 12 , and a pair of angle adjustment apparatuses (recliners) 1 . The angle adjustment apparatuses 1 angle-adjustably connect the seat back 11 and the seat cushion 12 . The seat back 11 has a first seat member (back frame) 11 a extending along a side surface of the seat back 11 . The seat cushion 12 has a second seat member (cushion frame) 12 a extending along a side surface of the seat cushion 12 .

As shown in FIGS. 1 to 3 , the angle adjustment apparatus 1 has a first member (ratchet) 2 , a second member (guide member) 3 , and a lock member 4 . The first member 2 is integrally provided with a main body 2 a and a flange 2 c , the main body 2 a having a circular plate shape, the flange 2 c being provided along an external periphery of the main body 2 a . The main body 2 a is provided with teeth 2 b , an attachment portion 2 d , and a projection pin 2 e . The teeth 2 b are provided to a surface facing the lock member 4 . The plurality of teeth 2 b are provided having an equal distance in between, along an entire circumference of an external portion of an internal surface of the main body 2 a.

The attachment portion 2 d is provided projecting in a direction away from the lock member 4 , as shown in FIG. 5 , and is attached to the first seat member 11 a by welding and the like. The projection pin 2 e is provided projecting toward the lock member 4 , as shown in FIG. 3 , and is inserted to an elongated groove 4 f provided to the lock member 4 . A hole 2 f is provided at the center of the main body 2 a , the hole 2 f penetrating the main body 2 a in a thickness direction. The flange 2 c has a ring shape and is rotatably held by the second member 3 .

The second member 3 is integrally provided with a main body 3 a and a flange 3 g , as shown in FIGS. 4 and 5 , the main body 3 a having a circular plate shape, the flange 3 g being provided along an external periphery of the main body 3 a . The main body 3 a is provided with a projection 3 d and an attachment recess 3 f . The projection 3 d is provided projecting in a direction away from the lock member 4 , and is attached to the second seat member 12 a by welding and the like. The attachment recess 3 f is provided to a surface facing the lock member 4 . A first end portion of a biasing member 7 is provided to the attachment recess 3 f . A hole 3 e is provided at the center of the main body 3 a , the hole 3 e penetrating the main body 3 a in a thickness direction.

The flange 3 g of the second member 3 has a ring shape, as shown in FIGS. 4 and 5 . The first member 2 is rotatably provided to an internal periphery of the flange 3 g . Rotation regulation portions 3 b are provided to an area of an internal peripheral surface in the axial direction of the flange 3 g . The plurality of rotation regulation portions 3 b are provided having a predetermined distance in between in the circumferential direction, and projecting from the flange 3 g toward the center of the main body 3 a . Recesses 3 c are provided between the rotation regulation portions 3 b . The rotation regulation portions 3 b and the recesses 3 c are engaged with the lock member 4 .

The lock member 4 is integrally provided with a main body 4 a having a circular plate shape and with a plurality of rotation regulation portions 4 c , as shown in FIGS. 3 and 4 . The plurality of rotation regulation portions 4 c are provided along an external periphery of the main body 4 a at a predetermined distance, and projecting radially externally from the main body 4 a . The rotation regulation portions 4 c are engaged with the recesses 3 c of the second member 3 , and regulate the lock member 4 a from being rotated relative to the second member 3 . Recesses 4 d are provided between the rotation regulation portions 4 c , and are engaged with the rotation regulation portions 3 b of the second member 3 .

The lock member 4 has a plurality of teeth 4 b , as shown in FIGS. 4 and 5 . The respective teeth 4 b are provided radially extending in the main body 4 a and the rotation regulation portions 4 c . The plurality of teeth 4 b are provided having a predetermined distance in between in the circumferential direction in a plurality of areas, along an external periphery of the lock member 4 . The teeth 4 b are provided to a surface of the lock member 4 facing the first member 2 , and are engaged with the teeth 2 b of the first member 2 . A hole 4 e is provided at the center of the main body 4 a , the hole 4 e penetrating the main body 4 a in a thickness direction. A rotation regulation portion 4 e 1 is provided to the hole 4 e , and thus the hole 4 e has a non-circular shape.

The lock member 4 is provided with the elongated groove 4 f having an arc shape, as shown in FIGS. 3 and 4 . The projection pin 2 e of the first member 2 is inserted to the elongated groove 4 f . When the projection pin 2 e is inserted to the elongated groove 4 f , the teeth 4 b of the lock member 4 are engaged with the teeth 2 b of the first member 2 . When the projection pin 2 e is not inserted to the elongated groove 4 f (free zone state), the projection pin 2 e is contacted with the main body 4 a of the lock member 4 , and thereby the teeth 4 b and the teeth 2 b are prevented from being engaged.

The biasing member 7 is provided between the lock member 4 and the second member 3 , as shown in FIGS. 3 and 4 . The biasing member 7 is, for instance, a coil spring. The first end portion of the biasing member 7 is provided to the attachment recess 3 f of the second member 3 , and a second end portion of the biasing member 7 is provided contacting the lock member 4 . The biasing member 7 is elastically deformed, and thereby the lock member 4 is biased against the first member 2 .

As shown in FIGS. 4 and 5 , the angle adjustment apparatus 1 has a mount member 8 , which regulates the first member 2 and the second member 3 from being axially disengaged. The mount member 8 is integrally provided with a ring main body 8 a , a first overhang 8 b , and a second overhang 8 c . The ring main body 8 a has a cylindrical shape, and covers an external peripheral surface of the first member 2 and an external peripheral surface of the second member 3 .

The first overhang 8 b has an annular shape, and is provided to an internal peripheral side of a first end portion of the ring main body 8 a , as shown in FIGS. 4 and 5 . The first overhang 8 b is provided axially adjacent to the first member 2 , and regulates the first member 2 from being moved in a direction disengaging from the second member 3 . The second overhang 8 c has an annular shape, and is provided to an internal peripheral side of a second end portion of the ring main body 8 a . The second overhang 8 c is provided axially adjacent to the second member 3 , and regulates the second member 3 from being moved in a direction disengaging from the first member 2 .

As shown in FIGS. 3 and 4 , the angle adjustment apparatus 1 has a movement mechanism 15 , which axially moves the lock member 4 . The movement mechanism 15 has an input member 5 and a drive member 6 . The drive member 6 is integrally provided with a main body 6 a , an end portion 6 c , and a projection (flange) 6 b . The main body 6 a has a tubular shape. An external peripheral surface of the main body 6 a is non-circular, since the surface has a rotation regulation surface 6 a 1 . When the main body 6 a is inserted to the hole 4 e of the lock member 4 , the rotation regulation surface 6 a 1 is provided opposite to the rotation regulation portion 4 e 1 . Thereby, the drive member 6 is regulated from being axially rotated relative to the lock member 4 , and is axially movably attached.

An engagement portion 6 d , 6 e (female thread) is provided to an internal peripheral surface of the main body 6 a , as shown in FIG. 5 . The engagement portion 6 d , 6 e includes a groove-shaped spiral 6 d (thread) extending axially and circumferentially and a projecting spiral 6 e (thread) extending axially and circumferentially.

The end portion 6 c of the drive member 6 has a cylindrical shape, as shown in FIGS. 3 and 4 , and is axially rotatably provided to the hole 2 f of the first member 2 . The projection 6 b is provided projecting radially externally from the main body 6 a , and projecting between the first member 2 and the lock member 4 . Thereby, the projection 6 b regulates the drive member 6 from being axially moved relative to the first member 2 and the lock member 4 .

The input member 5 is integrally provided with a main body 5 a , a projection 5 c , and a flange 5 b , as shown in FIGS. 3 and 4 . The main body 5 a has a cylindrical shape, and has an engagement portion 5 d , 5 e (male thread) on an external peripheral surface. The engagement portion 5 d , 5 e includes a projecting spiral 5 d (thread) and a groove-shaped spiral 5 e (thread), the projecting spiral 5 d projecting radially from the main body 5 a and extending axially and circumferentially, the groove-shaped spiral 5 e being provided between the projecting spiral 5 d and extending axially and circumferentially.

The projecting spiral 5 d is engaged with the groove-shaped spiral 6 d of the drive member 6 , as shown in FIG. 5 . The groove-shaped spiral 5 e is engaged with the projecting spiral 6 e of the drive member 6 . The main body 5 a is inserted to the hole 3 e of the second member 3 and the hole 6 f of the drive member 6 , as shown in FIGS. 4 and 5 . The main body 5 a passes through the drive member 6 , and thereby the main body 5 a passes through the hole 4 e of the lock member 4 and the hole 2 f of the first member 2 .

The flange 5 b of the input member 5 is provided projecting radially externally from the main body 5 a to an external side surface of the second member 3 , as shown in FIGS. 4 and 5 . An attachment member 9 is mounted to an end portion of the main body 5 a . The attachment member 9 has a ring shape. An internal peripheral portion thereof is mounted to the main body 5 a , and an external peripheral portion thereof is projected to the first member 2 . Thus, the input member 5 is regulated from being axially moved by the attachment member 9 and the flange 5 b.

The projection 5 c of the input member 5 is provided axially extending from the main body 5 a and projecting externally through the second member 3 , as shown in FIGS. 4 and 5 . A lever 14 is attached to the projection 5 c . The lever 14 is provided extending forward from the angle adjustment apparatus 1 , as shown in FIG. 1 . Lifting a front end portion of the lever 14 changes the angle adjustment apparatus 1 from a locked state of FIG. 5 to an unlocked state of FIG. 6 .

When the angle adjustment apparatus 1 is in the locked state, the biasing member 7 biases the lock member 4 against the first member 2 , as shown in FIG. 5 , and thus the teeth 4 b of the lock member 4 are engaged with the teeth 2 b of the first member 2 . The lock member 4 is regulated from being rotated relative to the second member 3 . Thus, the first member 2 and the second member 3 are regulated from being rotated, by the lock member 4 . Thereby, the first seat member 11 a and the second seat member 12 a are regulated from being rotated, by the angle adjustment apparatus 1 .

In order to unlock the angle adjustment apparatus 1 in the locked state, the end portion of the lever is lifted upward, as shown in FIG. 1 . The lever 14 is then axially rotated concurrently with the input member 5 , as shown in FIGS. 5 and 6 . Meanwhile, the drive member 6 is regulated from being rotated, by the lock member 4 and the first member 2 . When the input member 5 is axially rotated, the engagement portion 5 d , 5 e axially pushes the engagement portion 6 d , 6 e of the drive member 6 . Thereby, the drive member 6 is axially moved relative to the input member 5 .

The drive member 6 is moved from the first member 2 toward the second member 3 , as shown in FIG. 6 . The projection 6 b of the drive member 6 pushes the lock member 4 toward the second member 3 . The teeth 4 b of the lock member 4 are disengaged from the teeth 2 b of the first member 2 , and then the first member 2 is axially rotatable relative to the lock member 4 and the second member 3 . Thereby, the first seat member 11 a is rotatable relative to the second seat member 12 a , and thus the seat back 11 can be angle-adjusted relative to the seat cushion 12 , as shown in FIG. 1 .

When the force exerted on the lever 14 is released, the biasing member 7 pushes the lock member 4 toward the first member 2 , as shown in FIG. 5 . The angle adjustment apparatus 1 is then returned from the unlocked state to the locked state. When the seat back 11 is tilted forward more than a predetermined angle, however, the angle adjustment apparatus 1 enters the free zone state. In the free zone state, the projection pin 2 e is not inserted to the elongated groove 4 f , and is contacted with the main body 4 a of the lock member 4 , as shown in FIG. 3 . Thus, the lock member 4 and the first member 2 are not locked. Accordingly, even when the force exerted on the lever 14 is released, the seat back 11 is rotated from the tilted angle more forward than the predetermined angle to an angle aligned up with the seat cushion 12 .

As described above, the angle adjustment apparatus 1 has the lock member 4 and the movement mechanism 15 , as shown in FIG. 3 . The lock member 4 has the second teeth 4 b , which are engaged with the first teeth 2 b at a position radially external to the rotation center of the first member 2 and the second member 3 . The movement mechanism 15 has the input member 5 and the drive member 6 , the input member 5 being positioned at the rotation center of the first member 2 and the second member 3 and being regulated from being axially moved relative to the first member 2 and the second member 3 , the drive member 6 being provided between the external peripheral surface of the input member 5 and the lock member 4 and being regulated from being axially moved relative to the lock member 4 . The first engagement portion 5 d , 5 e is provided to the external peripheral surface of the input member 5 . The second engagement portion 6 d , 6 e , which is engaged with the first engagement portion 5 d , 5 e , is provided to the drive member 6 . The first engagement portion 5 d , 5 e , and the second engagement portion 6 d , 6 e are provided extending axially and circumferentially.

Thus, when the input member 5 is axially rotated, the drive member 6 is axially moved relative to the input member 5 , by the first engagement portion 5 d , 5 e , and the second engagement portion 6 d , 6 e . The drive member 6 is positioned radially external to the input member 5 . The lock member 4 , which is positioned radially external to the drive member 6 , is axially moved by the drive member 6 . Accordingly, an input torque is transferred from the radial center to the external side. The lock member 4 has the second teeth 4 b , which are engaged with the first teeth 2 b of the first member 2 at a position radially external to the drive member 6 . Thus, the lock member 4 and the first member 2 are mutually engaged with a relatively large torque. Accordingly, the respective members 4 to 6 are radially aligned without having radially crossing portions, and thus the lock member 4 and the first member 2 are engaged with a large torque. Thereby, the angle adjustment apparatus 1 can be configured simply, compared with a conventional configuration.

The biasing member 7 is provided between the second member 3 and the lock member 4 , as shown in FIGS. 3 and 4 , the biasing member 7 biasing the lock member 4 against the first member 2 . Thus, the teeth 4 b of the lock member 4 are engaged with the teeth 2 b of the first member 2 by a biasing force of the biasing member 7 .

The hole 4 e is provided at the axial center of the lock member 4 , as shown in FIGS. 3 and 4 . The drive member 6 has the main body 6 a and the first projection 6 b , the main body 6 a being inserted to the hole 4 e of the lock member 4 , and being axially movable and regulated from being axially rotated relative to the hole 4 e , the first projection 6 b projecting from the main body 6 a between the lock member 4 and the first member 2 . Thus, when the drive member 6 is moved from the first member 2 to the second member 3 , the drive member 6 pushes the lock member 4 against the biasing force of the biasing member 7 , and disengages the lock member 4 from the first teeth 2 b of the first member 2 .

When the drive member 6 is moved from the second member 3 to the first member 2 , meanwhile, the lock member 4 is engaged with the first teeth 2 b of the first member 2 by the biasing force of the biasing member 7 . Further, the drive member 6 is axially moved relative to the lock member 4 , even after the lock member 4 is engaged with the first member 2 . Thus, the drive member 6 is prevented from excessively pushing the lock member 4 against the first member 2 .

The input member 5 has the second projection 5 c axially projecting from the second member 3 and mounted with the lever 14 , as shown in FIG. 5 . Thus, rotating the lever 14 mounted to the input member 5 exerts an input torque on the input member 5 .

The first engagement portion 5 d , 5 e , and the second engagement portion 6 d , 6 e extending axially and circumferentially are threads, as shown in FIG. 5 . Thus, the first engagement portion 5 d , 5 e , and the second engagement portion 6 d , 6 e are formed relatively easily.

The angle adjustment apparatus 1 has the mount member 8 regulating the first member 2 and the second member 3 from being axially disengaged, as shown in FIG. 5 . Thus, the first member 2 and the second member 3 are not axially disengaged by the mount member 8 , and are mutually rotatably held in the axial direction.

The angle adjustment apparatus 1 has the projection pin 2 e provided to the first member 2 and the elongated groove 4 f provided to the lock member 4 , as shown in FIG. 3 . Thus, the first member 2 and the second member 3 are not locked in a predetermined rotation angle range, regardless of the movement mechanism 15 .

The present invention is not limited to the above-described embodiment. The present invention may also be an angle adjustment apparatus 21 , as shown in FIGS. 7 to 10 . The angle adjustment apparatus 21 has a first member 22 , a second member 23 , and a plurality of lock members 24 , as shown in FIGS. 7 and 8 .

The first member 22 has a similar configuration to the first member 2 of FIGS. 3 and 4 . As shown in FIGS. 7 and 8 , the first member 22 is integrally provided with a main body 22 a and a flange 22 c . The main body 22 a is provided with teeth 22 b , an attachment portion 22 d , a projection pin 22 e , and a hole 22 f.

The second member 23 has a similar configuration to the second member 3 of FIGS. 3 and 4 . As shown in FIGS. 7 and 8 , the second member 23 is integrally provided with a main body 23 a and a flange 23 g . The main body 23 a is provided with a projection 23 d and a hole 23 e . Rotation regulation portions 23 b and recesses 23 c are alternately provided on an internal periphery of the flange 23 g.

Each of the lock member 24 has a fan-shaped main body 24 a , as shown in FIGS. 7 and 8 . An external peripheral portion 24 a 2 of the main body 24 a is provided to the recess 23 c of the second member 23 . Recess-shaped rotation regulation portions 24 c are provided to both end portions of the main body 24 a . The rotation regulation portions 24 c are engaged with the rotation regulation portions 23 b of the second member 23 . Thus, the lock members 24 are regulated from being rotated relative to the second member 23 . A plurality of teeth 24 b are provided to the external peripheral portion 24 a 2 , the teeth 24 b being engaged with the teeth 22 b of the first member 22 . A recess 24 d is provided to an internal peripheral portion 24 a 1 of the main body 24 a on a surface facing a release plate 30 .

As shown in FIGS. 7 and 9 , the release plate 30 is provided between the first member 22 and the lock members 24 . The release plate 30 has a main body 30 a having a disk shape. The main body 30 a is provided opposite to the internal peripheral portion 24 a 1 of the main body 24 a of the lock member 24 . Thus, the release plate 30 can axially push the lock member 24 toward the second member 23 . The main body 30 a is provided with a projection 30 b , an elongated groove 30 c , and a hole 30 d . The projection 30 b is inserted to the recess 24 d of the lock member 24 , and thus limits rotation of the release plate 30 relative to the lock member 24 .

The elongated groove 30 c is provided extending in an arc shape, as shown in FIGS. 7 and 8 . The projection pin 22 e of the first member 22 is inserted to the elongated groove 30 c . When the projection pin 22 e is inserted to the elongated groove 30 c , the teeth 24 b of the lock member 24 are allowed to be engaged with the teeth 22 b of the first member 22 . When the projection pin 22 e is not inserted to the elongated groove 30 c , the projection pin 22 e is contacted with the main body 30 a of the release plate 30 , and thus the teeth 24 b and the teeth 22 b are prevented from being engaged (free zone).

As shown in FIGS. 7 and 8 , a biasing member 27 is provided between the lock members 24 and the second member 23 . The biasing member 27 is a plate spring having a main body 27 a and a plurality of extensions 27 b . The main body 27 a has a ring shape, and is provided with a hole 27 d at the center. The extensions 27 b are provided extending radially and axially from the main body 27 a toward the lock members 24 . End portions of the extensions 27 b are provided with contacts 27 c contacting the lock members 24 . The main body 27 a is contacted with the second member 23 and the extensions 27 b are elastically deformed, and thereby the biasing member 27 biases the lock members 24 against the first member 22 .

As shown in FIGS. 7 and 8 , the angle adjustment apparatus 21 has a mount member 28 and a movement mechanism 31 . The mount member 28 has a similar configuration to the mount member 8 of FIGS. 3 and 4 . The mount member 28 is integrally provided with a ring main body 28 a , a first overhang 28 b , and a second overhang 28 c.

The movement mechanism 31 has an input member 25 and a drive member 26 , as shown in FIG. 7 . The drive member 26 has a similar configuration to the drive member 6 of FIG. 3 . The drive member 26 is integrally provided with a main body 26 a , an end portion 26 c , and a projection 26 b , as shown in FIGS. 7 and 9 .

A rotation regulation surface 26 a 1 is provided to an external peripheral surface of the main body 26 a , as shown in FIGS. 7 and 9 . When the main body 26 a is inserted to the hole 30 d of the release plate 30 , the rotation regulation surface 26 a 1 faces a rotation regulation portion 30 d 1 provided to the hole 30 d . Thus, the lock members 24 are regulated from being axially rotated relative to the release plate 30 , and are allowed to be axially moved. The projection 26 b is provided projecting radially externally from the main body 26 a , and projecting between the first member 22 and the release plate 30 . An engagement portion 26 d , 26 e (female thread) is provided to an internal peripheral surface of the main body 26 a of the drive member 26 .

The input member 25 has a similar configuration to the input member 5 of FIG. 3 . The input member 25 is integrally provided with a main body 25 a , a projection 25 c , and a flange 25 b , as shown in FIGS. 7 and 8 . An engagement portion 25 d , 25 e (male thread) is provided to an external peripheral surface of the main body 25 a . The main body 25 a passes through the drive member 26 , and an attachment member 29 is mounted to an end portion of the main body 25 a.

The first member 22 is provided with a plurality of grooves 22 g having a predetermined distance in between in the circumferential direction, as shown in FIG. 10 . The teeth 22 b are provided between the grooves 22 g . A chamfer 22 h is provided to an external periphery of an opening of each of the grooves 22 g , the chamber 22 h being inclined in a thickness direction from the main body 22 a to the groove 22 g . The chambers 22 h thus allow easy insertion of the teeth 24 b of the lock members 24 to the grooves 22 g.

When the angle adjustment apparatus 21 is in the locked state, as shown in FIG. 9 , the biasing member 27 biases the lock members 24 against the first member 22 . Thereby, the teeth 24 b of the lock members 24 are engaged with the teeth 22 b of the first member 22 .

When the angle adjustment apparatus 21 is unlocked from the locked state, the input member 25 is axially rotated. Thereby, the drive member 26 is axially moved relative to the input member 25 , and then the drive member 26 pushes the release plate 30 toward the second member 23 . The release plate 30 pushes the lock members 24 against the biasing force of the biasing member 27 , and thus the teeth 24 b of the lock members 24 are disengaged from the teeth 22 b of the first member 22 .

As described above, the angle adjustment apparatus 21 has the plurality of lock members 24 , which are provided having a predetermined distance in between around the rotation center, as shown in FIGS. 7 and 8 . Thus, each of the lock members 24 is engaged with the teeth 22 b of the first member 22 , without being regulated by the remaining lock members 24 . In a case in which a ring-shaped lock member is provided with a plurality of teeth along an entire periphery, for instance, the entire lock member is not engaged with the first member when one of the teeth can not be engaged with the teeth of the first member. According to the present embodiment, however, each of the lock members 24 is surely engaged with the teeth 22 b of the first member 22 , without being affected by the remaining lock members 24 .

The biasing member 27 is provided between the second member 23 an the lock members 24 , as shown in FIGS. 7 and 9 , the biasing member 27 biasing the lock members 24 against the first member 22 . The biasing member 27 is a plate spring having the main body 27 a and the plurality of extensions 27 b , the main body 27 a being provided with the hole 27 d to which the input member 25 is inserted, the plurality of extensions 27 b extending radially and axially from the main body 27 a toward the lock members 24 .

Thus, the biasing member 27 , which is the plate spring, is thin, and can be thinner than a coil spring and the like. Accordingly, an axial length of the angle adjustment apparatus 21 can be short. The biasing member 27 , which has the hole 27 d to which the input member 25 is inserted, can be easily mounted to the input member 25 and the like. Each of the lock members 24 , which is biased by each of the extensions 27 b of the biasing member 27 , can be biased by the biasing member 27 without being interfered by the remaining lock members 24 .

The first teeth 22 b are provided between the plurality of grooves 22 g provided to the main body 22 a of the first member 22 , as shown in FIG. 10 . The chamfers 22 h are provided to the external peripheries of the grooves 22 g . Thus, the chamfers 22 h allow easy insertion of the second teeth 24 b to the grooves 22 g , thus ensuring engagement of the second teeth 24 b and the first teeth 22 b.

Alternative Embodiments

The present invention is not limited to the above-described embodiments, but may be embodied in forms below. For instance, the first seat member 11 a of FIG. 1 is a back frame, and the second seat member 12 a is a cushion frame. However, the first seat member may be a cushion frame, and the second seat member may be a back frame. Alternatively, one of the first seat member and the second seat member may be a seat back, and the other member may be an arm rest, a table, or the like. Alternatively, one of the first seat member and the second seat member may be a seat cushion, and the other member may be a foot rest to support occupant's calves, and the like.

The drive member 6 of FIG. 3 is provided separately from the lock member 4 . The drive member, however, may be integrally provided with the lock member. The projecting spiral 6 e of the drive member 6 of FIG. 5 is provided extending axially and circumferentially. The projecting spiral of the drive member, however, may have a radially projected pin and the like.

The projecting spiral 5 d of the input member 5 of FIG. 5 is provided extending axially and circumferentially. The projecting spiral of the input member, however, may have a radially projected pin shape and the like. The input member 5 of FIG. 5 has the projection 5 c axially projecting from the second member 3 . The input member, however, may have a projection axially projecting from the first member, and a lever may be attached to the projection. The input member 5 of FIG. 5 is regulated from being axially moved relative to the first member 2 and the second member 3 . The input member, however, may be regulated from being axially moved relative to either of the first member or the second member.

The biasing member 7 of FIG. 3 is a coil spring, but may be a rubber. The biasing member 7 of FIG. 3 is provided between the lock member 4 and the second member 3 . The biasing member, however, may be provided between the lock member and the second member, so as to bias the lock member against the first member. The angle adjustment apparatus 1 of FIG. 3 has the biasing member 7 . The angle adjustment apparatus, however, may have no biasing member 7 , and the drive member may be regulated from being moved relative to the lock member in both axial directions. Thereby, the lock member moves in both axial directions concurrently with the drive member.

The angle adjustment apparatus 1 of FIG. 3 has the projection pin 2 e provided to the first member 2 , and the elongated groove 4 f provided to the lock member 4 . The angle adjustment apparatus, however, may have a projection pin provided to the lock member, and an elongated groove provided to the first member. The vehicle seat 10 of FIG. 1 is mounted to a vehicle, such as an automobile, but may also be mounted to a boat, an airplane, and the like.

In the alternative embodiments, the lock member may be provided with teeth provided between a plurality of grooves provided to a main body, and with chamfers to external peripheries of the grooves, similar to the first member 22 of FIG. 10 .

It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular structures, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.

The present invention is not limited to the above-described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention.