Seat slide device for a vehicle

[0002] This application is based on and claims priority under 35 U.S.C. § 119 with respect to Japanese Application No. 10(1998)-368677 filed on Dec. 25, 1998, the entire content of which is incorporated herein by reference.

[0003] The present invention generally relates to a seat device. More particularly, the present invention pertains to a seat device in which a walk-in mechanism is provided for resuming a predetermined seat position after adjusting the seat position upon passengers entering or exiting the rear seat in cooperation with seat reclining forward adjustment of the seat back with respect to the seat cushion.

[0004] Unexamined Published Japanese Patent Application (Kokai) No. H07 (1995)-81469 discloses a seat slide device for sliding the seat device back and forth on a vehicle floor, a lock plate for holding the seat device in the adjusted position on the floor by engaging the seat slide device with the lock plate, a release lever for releasing the engagement between the lock plate and the seat slide mechanism through operation of the release lever, and a hold member for controlling the operation of the release lever through engagement with the release lever when the lock plate engages the release lever.

[0005] The hold member includes a cantilever spring for causing the hold member to engage with the release lever. By bending the cantilever spring, the hold member can be disengaged from the release lever. However, the cantilever spring generally has a wide distribution of spring force characteristics. Also the spring force characteristics tend to degrade over time. This can bring about an unstable engagement overlapping portion and an unstable disengagement timing between the hold member and the release lever. As a result, it is very difficult to produce an accurate resumed seat position on the vehicle floor.

[0006] A need thus exists for a seat slide device for a vehicle which is not as susceptible to the drawbacks and disadvantages noted above.

[0007] In light of the foregoing, one aspect of the present invention involves a seat device for a vehicle that includes a seat slide device supporting a vehicle seat relative to the vehicle floor at a position that is slidably adjustable in a back and forth direction on the vehicle floor, a lock plate engageable with the seat slide device to hold the seat at a position on the vehicle floor, a release lever rotatably supported on the seat slide device for releasing engagement of the lock plate with the seat slide device to permit sliding movement of the vehicle seat, and a walk-in mechanism having a hold lever for engaging the release lever to control rotation of the release lever when the release lever engages the lock plate.

[0008] According to another aspect of the invention, a seat device for a vehicle includes a lower rail secured to the vehicle floor and an upper rail supporting a vehicle seat and slidably supported on the lower rail, a lock plate engageable with the upper rail to fix the upper rail with respect to the lower rail and hold the vehicle seat at a position with respect to the vehicle floor, a release lever rotatably supported on the seat slide device for releasing engagement of the lock plate with the upper rail to permit sliding movement of the vehicle seat, a spring secured to the upper rail to move the upper rail in a forward direction with respect to the lower rail when the engagement of the lock plate with the upper rail is released by the release lever, and a hold lever movable between one position in which the hold lever engages the release lever to prevent rotation of the release lever and another position in which the hold lever is out of engagement with the release lever to permit rotation of the release lever.

[0009] The foregoing and additional features of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawing figures in which like elements are designated by like reference numerals and wherein:

[0010] FIG. 1 is a perspective view of the seat device in accordance with the present invention;

[0011] FIG. 2 is a cross-sectional view of the seat slide device of the present invention shown in FIG. 1;

[0012] FIG. 3 is a side view of the seat slide device in accordance with the present invention;

[0013] FIG. 4 is a cross-sectional view of a portion of the seat slide device in the region the seat slide lock mechanism shown in FIG. 3;

[0014] FIG. 5 is an inner side view of the seat slide device in accordance with the present invention;

[0015] FIG. 6 is a cross-sectional view of a portion of the seat slide device in the region of the release lever;

[0016] FIG. 7 is a cross-sectional view of a portion of the seat slide device in the region of the hold lever of the walk-in device shown in FIG. 3;

[0017] FIG. 8 is a exploded perspective view of the walk-in device in accordance with the present invention; and

[0018] FIG. 9 is a front view of the walk-in device in accordance with the present invention.

[0019] As shown in FIGS. 1-3, the seat slide device 4 in accordance with the present invention includes a pair of lower rails 1, each of which is fixed to the vehicle floor. The lower rails include right and left lower rails arranged parallel to each other and secured to the vehicle floor by brackets 41. The lower rails 1, 1 each possess a U-shaped cross-section defined by a pair of side wall portions 11 and a base portion 12 connecting the side wall portions 11. The lower rails are elongated in the forward and rearward direction of the vehicle. Engagement flange portions 13 are formed on the lower rails 1, 1 and extend longitudinally along the lower rails 1. The engagement flange portions 13, 13 are spaced apart by a predetermined distance from each other, with each engagement flange portion 13 extending from the upper end of one of the side wall portions 11 and bending toward the inside of the lower rail 1.

[0020] A pair of upper rails 2 that are elongated in the forward and rearward direction of the vehicle are each slidably supported on a respective one of the lower rails 1. The upper rails 2 form right and left upper rails that are fixed by way of brackets 32 on the seat cushion frame 31 forming a part of the seat cushion of the vehicle seat 3. The cross-section of each upper rail 2 possesses an upside-down T-shaped configuration having a horizontal portion 21 and a vertical portion 22. Engagement flange portions 23 forming a part of the upper rail 2 extend from both edges of the upper rail horizontal portion 21. The engagement flange portions 23 are bent upward as seen in FIG. 4. The engagement flange portions 23 of the upper rail 2 engage the engagement flange portions 13 of the lower rail 1 through the intermediary of slide permitting elements (e.g. balls) that permit sliding movement between the upper and lower rails. Thus, each upper rail 2 is slidable supported on the respective lower rail 1 as to be able to slide back and forth. The horizontal portion 21 of the upper rail 2 is arranged parallel to the base portion 12 of the lower rail 1 by way of further slide permitting members (e.g., rollers). Also, as shown in FIGS. 2 and 4, the vertical portion 22 of the upper rail 2 extends upward between the engagement flange portions 13 of the lower rail 1.

[0021] The seat slide device 4 comprising the lower rails 1 and the upper rails 2 is adapted to allow the vehicle seat 3 to be adjustable back and forth with respect to the longitudinal direction of the vehicle. As shown in FIG. 3 and FIG. 5, a spring 42 is installed between the front end of the lower rail 1 and the rear end of the upper rail 2. The spring 42 applies a force which pulls the upper rail 2 in the forward direction.

[0022] As shown in FIG. 3 and FIG. 4, on each inner side of the side wall portions 11 of the lower rails 1, referring to the seat width direction (i.e., the right and left side in FIG. 4), a series of engagement openings 11ais formed. The openings 11aare formed with a predetermined spacing or distance between adjacent openings. A pair of penetration openings 13aare formed on each of the inner engagement flange portions 23 of each upper rail 2, referring to the seat width direction. The height of the penetration openings 13amatch or equal the height of the engagement openings 11a. A pair of auxiliary plates 24 is fixed on each inner side of the vertical portions 22 of each upper rail 2, referring to the seat width direction. The auxiliary plates 24 have engagement openings 24ahaving a height position matching the engagement openings 11a. A lock bracket 25 is fixed on the upper rail 2 together with the auxiliary plate 24. A lock plate 26 is pivotally held on the lock bracket 25 by a pin 25a. The lock plate 26 possesses engagement teeth 26awhich penetrate through the engagement openings 24aand the penetration openings 13a, and further are adapted to engage the engagement openings 11a. The lock plate 26 is biased by a spring 25bthat is set on the pin 25a. The lock plate 26 is biased by the spring 25bin the clockwise direction in FIG. 4 to cause the engagement teeth 26ato engage the engagement openings 11a. Thus the engagement teeth 26aare supported by the engagement openings 24aand the penetration openings 13alocated on both sides of the engagement openings 11a. Because the engagement teeth 26aare held at two portions by the penetration openings 13aand the engagement openings 24a, high lock strength can be achieved. An engagement flange portion 26bis formed on and extends from the lock plate 26 on a side opposite the engagement teeth 26awith respect to the pin 25a.

[0023] As shown in FIGS. 1 and 8, an operation lever 27 is pivotally held by a pin 27aon the inner face (referring to the seat width direction) of the vertical wall portion 22 of each upper rail 2. A flange portion 27bis formed on the rear end of the operation lever 27. An operation handle 43 is fixedly inserted into a hold portion 27cof the operation lever 27. To make the two operating levers 27 on both sides of the seat slide device operate together, an operation handle 43 is formed as a so-called loop handle. The operation handle 43 is arranged under the seat front edge and is fixed with the left and right side operating levers 27. The engagement flange portion 27bfaces the other engagement flange portion 26b, and is adapted to engage the engagement flange portion 26bat its lower portion. The operating lever 27 is biased by a spring 27dto space the engagement flange portion 27bfrom the engagement flange portion 26b. The spring 27dis arranged on a pin 27aand biases the operating lever 27 in the counter clockwise direction in FIG. 3.

[0024] By virtue of the engagement between the engagement teeth 26aof the lock plate 26 and the engagement opening 11aof the lower arm 11, the slide operation of the upper rail 2 on the lower rail 1 is limited or prevented so that the position of the seat 3 is held or fixed. By operating the operation handle 43, the operating lever 27 rotates against the force of the spring 27d, the engagement flange portion 27bcontacts the engagement flange portion 26band the lock plate 26 is thus rotated against the biasing force of the spring 25b. Thus, the engagement between the teeth portion 26aand the engagement openings 13ais released and so the upper rail 2 is able to freely slide on the lower rail 1. In this way, the position of the seat is adjustable.

[0025] As shown FIGS. 1 and 2, left and right lower arms 33 are fixed in a facing and parallel relationship to each other on the rear ends of respective frames 31. Also, left and right upper arms 34 are fixed in a facing and parallel relationship to each other on the lower portions of frames (not shown) which configure the seat back of the seat 3, and are supported pivotally by the lower arm 33. Pivot axles 35 are each supported on and penetrate one of the lower arms 33 and one of the upper arms 34. Ratchets 34aare formed on each of the upper arms 34. The ratchets 34aare formed along an arc having its center on the pivot axles 35. The lower arms slidably support pawls 33awhich are adapted to engage with the ratchet 34a. A cam member 35ais pivotally supported on each axle 35 and contacts one of the pawls 33a. The contact of the pawl 33aby the cam member 35aapplies a thrust force to the pawl 33aand maintains a meshing engagement between the ratchet 34aand pawl 33a. An operation handle 35bis fixed on the axle 35 and a connecting shaft 35cconnects both of the axles 35cso that the axles 35crotate together.

[0026] The seat reclining device 36 comprises the lower arm 33, the upper arm 34 and the axle 35, and adjusts the reclining angle of the seat back relative to the seat cushion. Between the lower arm 33 and the upper arm 34, a spring 37 is arranged to apply a spring force to recline or pivot the upper arm 34 forward.

[0027] The rotation of the upper arm 34 with respect to the lower arm 33 is controlled by the meshing engagement between the pawl 33aand the ratchet 34a. This engagement causes the seat back angle relative to the seat cushion to be held. By operating the operation handle 35b, the axles 35 rotate, the contact between the pawl 33aand the cam 35ais released, the pawl 33aslides, and the meshing engagement between the pawl 33aand the ratchet 34ais released. The rotation of the upper arm 34 relative to the lower arm 33 is thus made possible. The position of the seat back relative to the seat cushion, or the seat back angle, is thus adjustable. The operation handle 35bhas an extended portion for permitting hand operation from the front side of the seat as well as foot operation from the rear of the seat.

[0028] As shown in FIGS. 1, 2 and 9, a pair of reclining plates 51 are provided, each of which is pivotally supported on a respective one of the axles 35. On the outer side vertical wall portions 22 of the upper rails 2 (with reference to the seat width direction), a release lever 52 is pivotally held by a pin 52a. One end of each reclining plate 51 is arranged to engage a bracket 34bfixed on the upper arm 34 when the upper arm 34 rotates forward towards the lower arm 33 beyond a predetermined angle. The reclining plate 51 is rotated on the axle 35 by engagement with the bracket 34b. The other end of the reclining plate 51 is connected with the release lever 52 by a rod 53. On the release lever 52, an engagement pin 52bfixedly stands or is secured in facing relation to the vertical wall portion 22 of the upper rail 2. The engagement flange portion 27bof the operation lever 27 extends through the opening 22aon the vertical wall portion 22 of the upper rail 2. The upper face of the engagement flange portion 27bof the operation lever 27 is able to contact the engagement pin 52b. The release lever 52 is biased to move the engagement pin 52baway from the engagement flange portion 27bby a spring 52carranged on the pin 52a.

[0029] On the outer side of each upper rail 2 vertical wall portion 22, referring to the seat width direction, a hold lever 54 is pivotally held by a pin 54a. As shown in FIG. 9, the release lever 52 has an edge face at the same height level as the edge face of the hold lever 54. A shoulder portion 52dand projected portion 52eare formed on the outer edge face of the release lever 52 which faces the hold lever 54. An arm portion 54bwhich is adapted to engage the shoulder portion 52dand is also adapted to contact the projected portion 52eis formed on the hold lever 54. The hold lever 54 is biased in the clockwise direction in FIG. 5 by a spring 54carranged on a pin 54ato engage the arm portion 54bwith the shoulder portion 52d. Then, by the arm portion 54bof the hold lever 54 and the contact between the release lever 52 and the projected portions 52e, the hold lever 54 rotation is held against the force of the spring 54cforce.

[0030] On the outer side of the engagement flange portion 13 and the outer side face of the side wall portions 11 of each lower rail 1, referring to the seat width direction (i.e., the right and left side direction in FIG. 4), a memory plate 55 is fixed. A foot portion 54dof the hold lever 54 is adapted to engage the memory plate 55 and to maintain the hold lever 54 in the disengagement position with the shoulder portion 52dof the release lever 52, while the seat is in the usual sitting position.

[0031] The walk-in operation associated with the seat slide device of the present invention is as follows. As shown in FIG. 9, during the forward folding operation when the seat back is reclined forward towards the seat cushion beyond a predetermined angle, the bracket 34bof the upper arm 34 contacts the reclining plate 51, thus causing the reclining plate 51 to rotate in the counter clockwise direction in FIG. 9. The rod 53 is thus pulled rearward by the rotation of the reclining plate 51 and the release lever 52 rotates in the counter clockwise direction in FIG. 9 against the biasing force of the spring 52c. Then, the engagement pin 52bof the release lever 52 contacts the upper face of the engagement flange portion 27bof the operation lever 27 and pushes the engagement flange portion 27bdownwardly. The operation lever 27 is thus rotated in the clockwise direction in FIG. 3 against the biasing force of the spring 27d, and the lower face of the engagement flange portion 27bcontacts the engagement flange portion 26bof the lock plate 26 and pushes the engagement flange portion 26bdownwardly. This causes the lock plate 26 to rotate in the counter clockwise direction in FIG. 4 against the biasing force of the spring 25b. Thus the teeth portion 26aof the lock plate 26 disengage from the engagement openings 11aof the lower rail 11 so that the upper rail moves forward on the lower rail by the biasing forced of the spring 42. The position of the seat 3 on the vehicle floor is thus adjustable.

[0032] After the foregoing operation, and after the seat has been moved to the front or forward position where the memory plate 55 does not engage with the foot portion 54dof the hold lever 54, the hold lever 54 is rotated in the counter clockwise direction in FIG. 9 by the biasing force of the spring 54c, because the contact between the projection parts 52eof the release lever 52 and the arm portion 54bof the hold lever 54 is released by the rotation of the release lever 52. The arm portion 54bengages the shoulder portion 52dof the release lever 52 and the clockwise rotation of the release lever 52 in FIG. 9 by the biasing force of the spring 52cis limited or prevented. The engagement between the engagement teeth 26aof the lock plate 26 and the engagement openings 11aof the lower arm 11 is maintained in the released condition. In this condition, the foot portion 54dof the hold lever 54 remains on the moving path of the memory plate 55.

[0033] When the seat back is returned rearward to the original upright position from the forwardly folded position, and the seat 3 is moved back along the floor to the original position, which adjusting operations can be performed simultaneously, the bracket 34bof the upper arm 34 moves away from the reclining plate 51. At the same time, the foot portion 54dof the hold lever 54 hits on the front edge of the memory plate 55, and the hold lever 54 is rotated in the clockwise direction in FIG. 9 against the biasing force of the spring 54c, with the engagement between the arm portion 54band the shoulder portion 52dof the release lever 52 being released so that the release lever 52 rotates in the clockwise direction in FIG. 9 by the biasing force of the spring 52c. As a result, the contact between the engagement pin 52bof the release lever 52 and the upper face of the engagement flange portion 27bof the operation lever 27, and the contact between the lower face of the engagement flange 27band the engagement flange 26bof the lock plate 26 are released, whereby the lock plate 26 rotates in the clockwise direction in FIG. 4 by the force of the spring 25b. The teeth portion 26aof the lock plate 26 thus engage with the engagement opening 11aof the lower rail 1 so that the slide operation of the upper rail 2 on the lower rail 1 is limited or prevented. The seat position is thus held at resumed position. The memory plate 55 position determines the seat 3 position on the floor.

[0034] In the usual use position of the seat, the rotation of the hold lever 54 is restricted by the engagement of the arm portion 54band the projection portion 52eof the release lever 52. The arm portion 54dis thus kept on the outside position of the movement path of the memory plate 55. Then the chattering noise from the contact with the memory plate or the unexpected interference between the upper arm 2 does not occur.

[0035] According to the present invention, the rotation of the hold lever pivotally supported on the seat slide device is controlled by the engagement between the lock plate. By making the engagement lapping portion between the release lever be constant and also the spring force applied on them constant, the engagement or disengagement timing of them is improved to be constant. As a result, the resumed position of the seat can be constant.

[0036] The principles, preferred embodiment and modes of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiment disclosed. Further, the embodiment described herein is to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.