Automotive seat with walk-in mechanism

Abstract: An automotive seat structure includes a seat cushion (A) and a seat back (B) which is operable for selecting a seat back (B) reclining position at first position, for frontwardly inclined position for providing space for a passenger to pass therethrough at a second position and for orienting the seat back (B) at substantially horizontal position. The seat structure comprises a base plate (1) fixed to the seat cushion (A), a first arm (2) pivotably mounted on the base plate (1), a second arm (8) fixed to the seat back (B) of the seat, the second arm (8) being pivotally connected to the first arm (2) at one end, a first locking means for locking the first and second arms in substantially alignment with each other, a second locking means for locking the first (2) and second arms (8) locked in alignment by the first means at a selected angular position relative to the seat cushion (A) at the first position of the seat back (B), a third locking means for locking the second arm (8) while the seat back (B) is placed at the third position, and a manually operable member associated with the first arm (2) for pivotal movement therewith, the manually operable member having first component extending frontwardly and a second component extending rear wardly, the first and second components being selectively operable to a first operational position for releasing locking of the second locking means for permitting pivotal movement of the second arm (8) with the seat back (B) into the second position, and at least one of the first components being further operable to second operational position to release locking of the first means for pivoting the second arm (8) relative to the first arm (2) for establishing the third position of the seat back (B) while the locking of the second locking means is released.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to a seat structure for an automotive vehicle. More specifically, the invention relates to an automotive seat structure with a walk-in mechanism for frontwardly inclining a seat back and, simultaneously, shifting the seat frontwardly for providing a clearance for passing into a rear seat. Further particularly, the invention relates to an automotive seat structure which can fold the seat back beyond the frontwardly inclined position for orienting the back side of the seat back substantially in horizontal so that the back side of the seat back can be used as a table. Additionally, the invention relates to a seat structure which is particularly adapted for a cab-over type wagon, or mini-bus having front, center and rear seats. Description of the Background Art Japanese Patent First (unexamined) Publication (Tokkai) Showa 62-29440 disclose an automotive seat, particularly adapted for cab-over type wagon. The disclosed seat is particularly designed as center or intermediate seat in particular type of wagon having front, center or intermediate and rear seats. The seat has a seat back to be inclined frontwardly. Also, the seat is slidable frontwardly when the seat back is inclined so as to provide a passage for rear seat passengers to pass therethrough. Such mechanism is per se known as walk-in mechanism. The above-identified prior proposed invention further proposes the seat which has a seat back being capable of further inclined so that the back side of the seat back can be oriented substantially in horizontal. Such seat back position may be hereafter referred to as "folded position". At the folded position, the back side oriented substantially horizontally may serve for placing luggage, or, in the alternative, for use as a table. In such an automotive seat, it is essential to maintain a satisfactorily high level of safety. Therefore, in the case of the automotive seat with walk-in mechanism, it has to be assured that as assist lever for operating a walk-in lever is strong enough that the walk-in mechanism will never be operated into the walk-in position unintentionally. This requirement necessarily makes the assist lever bulky. Also, since the walk-in lever is oriented above the slide lock lever, the vertical dimension becomes necessary for facilitating this walk-in lever. DE-A-2 738 599, on which the preambles of the independent claims are based, discloses a hinge fitting for a vehicle seat with a seat bracket bolted to the seat cushion, a link or middle member pivoted to the seat bracket, and a back rest bracket fixed to the seat back and pivoted to the link member. The link member is pivoted relative to the seat bracket to adjust the angle of the seat back, and the back rest bracket is pivoted relative to the link member to fold the seat back flat forwards. A connecting member pivoted to the link member engages both the seat bracket and the back rest bracket to lock the seat into position. Rotation of an operating lever causes a cam to raise the link member vertically, disengaging the connecting member and enabling the seat back to be pivoted as desired. DE-A-2 317 926 discloses a seat that can be tipped up as a whole. A latch is released by operating a foot pedal, either in front of or behind the seat. The invention provides a hinge structure for an automotive seat which is operable for selecting a seat back reclining position for said seat at a first position, for inclining forwardly for providing space for a passenger to pass thereby at a second position, and for orienting said seat back substantially horizontally at a third position, said hinge structure comprising: a base plate secured to a seat cushion of said automotive seat; a lower arm pivotally mounted on said base plate; an upper arm secured to said seat back and pivotably connected to said lower arm; and latch means pivotally mounted on said lower arm and engageable with said upper arm and said base plate; characterised in that said latch means comprises an upper latch pivotally mounted on said lower arm and engageable with said upper arm, a lower latch engageable between said base plate and said lower arm, and a link cooperably connecting said upper and lower latches; and in that an elastic member is mounted on said upper latch for elastic contact with said upper arm. The invention also provides an automotive seat assembly including a seat cushion and a seat back, said seat back being operable for selection of a seat back reclining angle in a first position, for forward inclination for allowing passenger access in a second position, and for being oriented in fully forward, substantially horizontal position in a third position, said seat assembly comprising: a base plate fixed to said seat cushion; a lower arm pivotably supported on said base plate; an operation lever; an upper arm rigidly fixed to a seat back of said seat; a locking pin extending from one end of said upper arm; and a catching lever pivotably mounted on said lower arm and releasably engaging with said locking pin of said upper arm; characterised by said lower arm being biased in a predetermined pivotal direction by a spring; said operation lever being provided for pivotal movement with said lower arm; by a tooth member cooperable with said operation lever for releasably establishing locking engagement with said lower arm; a swing lever for pivotally moving said tooth member for establishing and releasing locking engagement with said lower arm; and a link lever associated with said catching lever for causing pivotal movement thereof, said link lever being cooperably connected to said swing lever. Preferably, the automotive seat structure further comprises an elastic member associated with the upper arm for elastically biasing the upper arm for eliminating free movement of the second arm due to play. Also, the automotive seat structure may comprise a walk-in mechanism including seat sliding means for shifting said seat back and forth, said walk-in mechanism including a seat lock mechanism for locking said seat sliding means, said walk-in mechanism including a walk-in lever associated with said operation lever for synchronizing release of said seat lock mechanism locking said seat sliding means with manual operation of said operation lever for moving said seat back to said second position. The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments but are for explanation and understanding only. In the drawings: Fig. 1 is a perspective illustration of an automotive seat for which the preferred embodiment of a seat structure according to the present invention is applicable; Fig.2 is a side elevation showing the major part of the first embodiment of an automotive seat structure according to the present invention; Fig. 3 is a front elevation of the major part of the first embodiment of the automotive seat structure according to the invention; Fig. 4 is a perspective view of a seat slide construction employed in the first embodiment of the automotive seat structure; Figs. 5 and 6 are side elevation showing variety of seat positions to be implemented by the first embodiment of the automotive seat structure of Figs. 1 through 4 ; Fig. 7 is a slide elevation similar to Fig. 1 but showing the major part of the second embodiment of the automotive seat structure according to the invention; Fig. 8 is a front elevation of the seat mechanism of Fig. 7 ; Fig. 9 is a side elevation similar to Fig. 7 but showing the automotive seat structure operated in variety of positions; Fig. 10 is a side elevation of the preferred construction of a seat back hing employed in the preferred embodiment of the seat structure; Fig. 11 is a front elevation of the seat back hinge of Fig. 10 ; Fig. 12 is an enlarged section of the major part of the seat back hinge of Figs. 10 and 11 ; and Fig. 13 is a side elevatiation showing operation of the preferred construction of seat back hinge. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, particularly to Fig. 1 , the preferred embodiment of an automotive seat, according to the present invention, has a seat cushion A and a seat back B pivotably adjoined with the rear end of the seat cushion. A seat back adjusting mechanism C is provided between the seat cushion A and the seat back B for pivotally adjusting seat back position relative to the seat cushion. The seat back adjusting mechanism C includes a seat back reclining mechanism D for adjusting seat back angular position backward from a predetermined neutral position, and a walk-in seat back adjusting mechanism for permitting the seat back B to be tilted frontwardly from the neutral position. The seat back adjusting mechanism C further includes a double arm structure E for permitting the seat back B to be folded into a folded position, in which the back side of the seat back B is oriented substantially in horizontal as shown by phantom line. At the folded position, the back side of the seat back B can be used as table or luggage shelf for placing drink, food, luggage and so forth. The double arm structure E generally comprises a lower arm 2 and an upper arm 8 which is connected to the upper end of the lower arm in pivotal fashion. The lower arm 2 is associated with a seat back reclining mechanism D fixed on the rear end of a seat cushion frame which is not shown. On the other hand, the upper arm 8 is rigidly secured on a seat cushion frame which is not shown. The lower and upper arms 2 and 8 are normally locked for serving as an integrally formed arm. The upper arm 8 is pivotable with carrying the seat back B for placing the seat back to the folded position. The preferred embodiments of the automotive seat structure according to the present invention will be discussed in greater detail herebelow with reference to Figs. 2 through 13 . Referring to Figs. 2 and 3 , a base plate 1 is rigidly secured onto the seat cushion frame supporting seat cushion A . The lower arm 2 is pivotable about a pivot shaft 3 which extends from the base plate 1 . An arc shaped slot 4 is formed through the base plate 1 , through which a pin 5 projected from the lower arm 2 extends. Therefore, the pivotal movement of the lower arm 2 is guided and restricted by the arc shaped slot 4 . A spiral spring 6 is provided between the pivot shaft 3 and the pin 5 so as to normally bias the lower arm 2 in couterclockwise direction in Fig. 2 . The upper arm 8 is pivotably connected to the upper end of the lower arm 2 for pivotal movement about a pivot 9 . The upper arm 8 has a locking pin 10 in the vicinity of the lower end thereof. The locking pin 10 is engageable with a catching lever 11 which is pivotable about a pivot 12 . The catching lever 11 is normally biased in clockwise direction in Fig. 2 by means of a coil spring 13 which has one end connected to a projection 13a projecting from the upper arm 8 and a projection 13b projecting from the catching lever 11 . The catching lever 11 defines a locking pin receptable recess 14 for establishing locking engagement between the locking pin 10 and the catching lever 11 . The catching lever 11 is integrally formed with a lever section 15 which is oriented substantially perpendicular to the major section. A lock release lever 16 is pivotable about a shaft 17 and oriented in the vicinity of the catching lever 11 so that the lever may contact with the locking pin 10 . The lock release lever 16 has an upper edge 18 where it contact with the locking pin 10 and formed into arc shaped configuration. The lock release lever 16 has a bifurcated legs 19 and 19a . The lock release lever 16 is biased in counterclockwise direction by means of a torsional spring 20 . The leg 19a of the lock release lever 16 is associated with a walk-in lever 21 is pivotally supported by the pivot 3 for pivotal movement thereabout. The walk-in lever 21 has an integrally formed actuation lever section 22 which is oriented in opposition to the leg 19 of the lock release lever 16 . The walk-in lever 21 is connected to an actuation wire 23 which extends through a flexible guide tube 25 , end of which is secured to the seat cushion frame by means of a fastening bracket 24 . Through the actuation wire 23 , the walk-in lever 21 is connected to a walk-in mechanism F . An operation lever 26 is pivotable about the shaft 3 . The operation lever 26 has a lever section 28 which has one end mounted thereon a manual grouper handle 27 . The operation lever 26 is also provided with a foot pedal 29 . A return spring 30 is provided between the operation lever 26 and a holder plate 31 for biasing the operation lever in counterclockwise direction in Fig. 2 . A tooth member 32 is disposed between the base plate 1 and the holder plate 31 and pivotable about a pivot 33 . The tooth member 32 has a locking tooth 35 . The locking tooth 35 is designed for engagement with a locking tooth 34 formed on the outer periphery of the lower arm 2 . A pin 36 extends from a swing lever 43 and extends through an elongated opening 38 formed through the holder plate 31 . Furthermore, the pin 36 extends through an elongated opening 37 of the operation lever 26 . A cam member 39 is provided for pivotal movement about a shaft 40 on the base plate 1 . The cam member 39 is formed a leg 42 which is engageable with a recess 41 of the tooth member 32 . The swing lever 43 is connected with the cam member 39 via an emboss section 44 to be formed into crank shaped configuration as assembled together with the cam member 39 . The swing lever 43 is pivotable about a pivot 40 together with the cam member 39 . The pin 36 which extends though the elongated opening 37 is extended from the swing lever 43 . A link lever 45 is connected to the swing lever 43 via a connecting pin 46 at one end and has a contact pin 47 which contacts with the lever section 15 of the catching lever 11 . A link 48 is pivotally connected to the link lever 45 at one end and to the holder plate 31 at the other end. A stationary damper housing 50 is secured on the lower arm 2 . The stationary damper housing 50 serves as stopper for the pivot 12 of the catching lever 11 . A rubber damper 51 is housed within the stationary damper housing 50 . The rubber damper 51 is frictionally engageable with the side face of the upper arm 8 . An axis a extending through the pivot 12 of the catching lever 11 and the locking pin 10 , and an axis b extending through the locking pin 10 and the pivot 9 of the upper arm 8 intersects to reach other with an angle smaller than or equal to 90°. As shown in Fig. 4 , the walk-in mechanism F includes a seat slide rail 52 including a stationary rail rigidly secured on the floor of the vehicular body and a movable rail. A bracket 53 is secured on the movable rail. The bracket 53 supports a locking lever 56 which is biased by means of a spring 54 for locking engagement with one of a plurality of locking holes 55 formed through the stationary rail. The actuation wire 23 is connected to the free end of the locking lever 56 . A guide bracket 57 is provided for guiding the wire 23 so that the wire can be arranged in alignment with the locking lever 56 at least at the end thereof. In the operation of the aforementioned first embodiment of the automotive structure, the seat back reclining mechanism E can be operated through the operation lever 26 . Namely, by pulling up the operation lever 26 to the uppermost position 26a in clockwise direction in Fig. 1 , the swing lever 43 is pivotally moved about the pivot 40 via the pin 36 . According to pivotal movement of the swing lever 43 the cam member 39, which is integrated with the swing lever and engages the leg 42 with the recess 41 of the tooth member 32 , pivotally moves to cause clockwise rotation of the tooth member 32 about the pivot 33 . By this pivotal movement, the locking engagement between the teeth 34 and 35 is released. By this, the lower arm 2 is permitted to pivot about the pivot 3 . At this position, the force of the spiral spring 6 becomes active for causing forward pivotal movement of the seat back B . However, since the spring force of the spiral spring 6 is not too strong, the seat back will stop moving forwards on contacting a seat occupant's back. On the other hand, by pushing the seat back B against the spring force, the occupant can tilt the seat back B rearwards to increase the reclining angle. When the operation lever 26 is released from its upward position, it is returned to the initial position by the spring force of the spring 30. The pin 36 then causes clockwise pivotal movement of the swing lever 43 . As a result, the cam member 39 pivots in the clockwise direction to release the leg 42 from the recess 41 of the tooth member 32 . Therefore, the tooth member 32 pivots in the counterclockwise direction to cause engagement between the teeth 34 and 35 . Therefore, the lower arm 2 is locked at the selected position. It should be appreciated that with the shown construction, the seat back reclining mechanism permits reclining adjustment between the neutral position P and a fully reclined position Q . When the walk-in mechanism F is to be used, the operation lever 26 is pulled upwardly or the foot pedal 29 is operated. By this, the operation lever 26 is pivoted about the pivot 3 in clockwise direction. Accordingly, the locking engagement between the teeth 34 and 35 is release. Therefore, the lower arm 2 becomes free from the locking engagement. Therefore, the lower arm 2 is pivoted by means of the spiral spring 6 . As can be appreciated, since the walk-in mechanism F is operable in absence of the seat occupant, the lower arm 2 is inclined or tilted frontwardly. At the same time, the pin 5 is pivotally moved along the arc shaped elongated slot 4 of the lower arm 2 . In synchronism with the seat back tilting operation , the lever section 15 of the swing lever comes into contact with the link lever 47 . This causes slight pivotal movement of the catching lever 11 about the pivot 12 in counterclockwise direction. Therefore, incomplete locking between the locking pin receptacle recess 14 of the catching lever 11 and the locking pin 10 is established. When the seat back B is inclined frontwardly, the leg 19 of the lock release lever 16 comes into contact with the leg 22 of the walk-in lever 21 to cause the latter to pivot about the pivot 3 in counterclosewise direction. By this, the actuation wire 32 is pulled for a predetermined direction to pull the locking lever 56 in lock releasing position for causing frontward shifting the movable rail with the seat structure. On the other hand, when the seat back B is to be placed at the folded position for placing the back side of the seat back substantially in horizontal, the operation lever 26 is initially pulled up to the uppermost position 26a as set forth above for causing frontward inclination. At this position, the link lever 45 is placed at a downwardly shifted position since it is depressed downwardly by the lever section 15 of the catching lever 11 . Subsequently, the operation lever 26 is operated to return into the half pulled-up position as represented by 26b . By this, the swing lever 43 pivotally moves about the pivot 40 in clockwise direction. By this, the link lever 45 shifts upwardly to push the the lever section 15 of the catching lever 11 by the contacting pin 47 . As a result, the catching lever 11 is pivoted in the counterclockwise direction. Therefore, the locking pin 10 and the locking pin receptacle recess 14 of the catching lever 11 , which are placed in incomplete engagement state by initially pulling the operation lever 26 in uppermost position 26a , are released. By this, the upper arm 8 becomes free to pivot about the pivot 9 . With the shown construction, the catching lever 11 is designed for slight pivotal movement according to forward tilting movement of the lower arm 2 and maintain the angle between the axes a and b smaller than or equal to 90° , the locking pin 10 becomes easily released from locking engagement with the catching lever 11 . Therefore, despite the force exerted on the catching lever 11 for depressing the upper arm 8 onto the rubber damper 51 , the operational force required for releasing locking engagement between the locking pin 10 and the catching lever 11 becomes small. By pushing the seat back B forwardly into the folded position, the upper arm 8 pivots about the pivot 9 in the counterclockwise direction. Then, a pin 13a receiving one end of the coil spring 13 comes into engagement with the recess 2a of the lower arm 2 . The engagement of the pin 13a and the recess 2a , in cooperation with the spring 13 , ensures that the seat back is maintained in the folded position R . According to pivotal movement of the upper arm 8 as set forth above, the locking pin 10 is shifted off the guide edge 18 of the lock release lever 16 which pushes the lever section 22 of the walk-in lever 21 . As a result, the lock release lever 16 is pivoted about the pivot 17 by means of the spring 20 in counterclockwise direction to place the leg 19a into contact with the pin 5 . As a result, the leg 19 is released from the lever section 22 of the walk-in lever 21 . Therefore, the walk-in lever 21 is forced into pivotal motion by the spring force of the spring 54 via the wire 23 , in clockwise direction. Therefore, the walk-in mechanism D is again placed into locking state. Therefore, the movable rail with the seat cushion is locked to the stationary lever at forwardly shifted position. Therefore, the seat placed at the folded position can be stably maintained. For returning the seat back B from the folded position to the normal position, the upper arm 8 with the seat back is pivoted clockwise, as shown in Fig. 6 . The locking pin 10 comes into contact with the guide edge 18 of the lock release lever 16 to cause clockwise pivotal movement of the latter. Then, the leg 19 of the lock release lever 16 again pushes the leg 22 of the walk-in lever 21 for causing counterclockwise pivotal movement about the pivot 3 of the walk-in lever. By this, the actuation wire 23 is again pulled to release locking of the walk-in mechanism C . At the same time, the locking pin 10 comes into engagement with the locking pin receptacle recess 14 of the catching lever 11 . Furthermore, the side face of the upper arm 8 comes into contact with the rubber damper 51 . Also, the pin 13a shifts from the recess 2a for causing integrally locking of the lower and upper arms 2 and 8 . Then, the movable rail of the seat slide 52 is shifted rearwardly on the stationary rail. Simultaneously, the tilt angle of the seat back B is adjusted to the desired position in the manner discussed with respect to the operation of the seat back reclining mechanism. As desired, the tooth 35 of the tooth member 32 and the tooth 34 of the lower arm 2 comes into engagement. Therefore, the seat back B is fixedly maintained at the selected angular position as illustrated by P . Figs. 7 through 9 shows the second embodiment of the automotive seat structure, according to the present invention. As shown in Figs. 7 and 8 , a base plate 101 is rigidly secured onto the seat cushion frame supporting seat cushion A . The lower arm 102 is pivotable about a pivot shaft 103 which extends from the base plate 101 . An arc shaped slot 104 is formed through the base plate 101 , through which a pin 105 projected from the lower arm 102 extends. Therefore, the pivotal movement of the lower arm 102 is guided and restricted by the arc shaped slot 104 . A spiral spring 106 is provided between the pivot shaft 103 and the pin 105 so as to normally bias the lower arm 102 counterclockwise in Fig. 7 . The upper arm 108 is pivotably connected to the upper end of the lower arm 102 for pivotal movement about a pivot 109 . The upper arm 108 has a locking pin 110 in the vicinity of the lower end thereof. The locking pin 110 is engageable with a catching lever 111 which is pivotable about a pivot 112 . The catching lever 111 is normally biased in the clockwise direction in Fig. 7 by means of a coil spring 113 which has one end connected to a projection 109 projecting from the upper arm 108 and a projection 113b projecting from the catching lever 111 . The catching lever 111 defines a locking pin receptable recess 114 for establishing locking engagement between the locking pin 110 and the catching lever 111 . The catching lever 111 is integrally formed with a lever section 115 which is oriented substantially perpendicular to the major section. The lever section 115 is formed with a pin 116 . The pin 116 is engageable with an elongated arc shaped opening 117 having arc radius centered at the pivot 112 of the lower arm 102 . When the lower arm 102 is tilted forwardly, it comes into contact with an emboss pressed stopper 118 on the base plate 101 . A plate lever 119 is pivotable about the locking pin 110 of the upper arm 108 . The upper arm 108 has a stopper 120 projecting therefrom. The stopper 120 is designed to contact with the side edge of the lower arm 102 when the upper arm is tilted forwardly. A walk-in lever 121 is pivotally supported by the pivot 103 for pivotal movement thereabout. The walk-in lever 121 has an integrally formed actuation lever section 122 which is oriented in opposition to the leg 119 of the lock release lever 116 . The walk-in lever 121 is connected to an actuation wire 123 which extends through a flexible guide tube 125 , end of which is secured to the seat cushion frame by means of a fastening bracket 124 . Through the actuation wire 123 , the walk-in lever 121 is connected to a walk-in mechanism F . An operation lever 126 is pivotable about the shaft 103 . The operation lever 126 has a lever section 128 which has one end mounted thereon a manual gripper handle 127 . The operation lever 126 is also provided with a foot pedal 129 . A return spring 130 is provided between the operation lever 126 and a holder plate 131 for biasing the operation lever in counterclockwise direction in Fig. 7 . A tooth member 132 is disposed between the base plate 101 and the holder plate 131 and pivotable about a pivot 133 . The tooth member 132 has a locking tooth 135 . The locking tooth 135 is designed for engagement with a locking tooth 134 formed on the outer periphery of the lower arm 102 . A pin 136 extends from a swing lever 143 and extends through an elongated opening 138 formed through the holder plate 131 . Furthermore, the pin 136 extends through an elongated opening 137 of the operation lever 126 . A cam member 139 is provided for pivotal movement about a shaft 140 on the base plate 101 . The cam member 139 is formed a leg 142 which is engageable with a recess 141 of the tooth member 132 . The swing lever 143 is connected with the cam member 139 via an emboss section 144 to be formed into crank shaped configuration as assembled together with the cam member 139 . The swing lever 143 is pivotable about a pivot 140 together with the cam member 139 . The pin 136 which extends though the elongated opening 137 is extended from the swing lever 143 . A swing lever 146 is pivotable with a common pivot of the tooth member 132 , at one end. The other end of the swing lever 146 is formed into a configuration adapted to contact with the pin 116 of the catching lever 111 . The swing lever 146 is formed with an elongated opening 148 which is engageable with a projection 149 on the operation lever 112 . It should be appreciated that the attached drawings show the walk-in mechanism in the second embodiment. However, it should be appreciated that the construction of the walk-in mechanism in the second embodiment is identical to that illustrated in Fig. 4 . Therefore, all elements of the walk-in mechanism are represented by the reference numerals "100" greater than the first embodiment. Therefore, it should be appreciated that the elements are of the same construction and function as that of the first embodiment having the same number to the lower two digit of figures in this embodiment. A stationary damper housing 150 is secured on the lower arm 102 . The stationary damper housing 150 serves as stopper for the pivot 112 of the catching lever 111 . A rubber damper 151 is housed within the stationary damper housing 150 . The rubber damper 151 is frictionally engageable with the side face of the upper arm 108 . In the operation of the aforementioned second embodiment of the automotive structure, the seat back reclining mechanism E can be operated through the operation lever 126 . Namely, by pulling up the operation lever 126 to the uppermost position 126a in clockwise direction in Fig. 2 , the swing lever 143 is pivotally moved about the pivot 140 via the pin 136 . According to pivotal movement of the swing lever 143 , the cam member 139 , which is integrated with the swing lever and engages the leg 142 with the recess 141 of the tooth member 132 , pivotally moves to cause clockwise rotation of the tooth member 132 about the pivot 133 . By this pivotal movement, the locking engagement between teeth 134 and 135 is released. By this, the lower arm 102 is permitted to pivot about the pivot 103 . At this position, the force of the spiral spring 106 becomes active to cause forward pivotal movement of the seat back B . However, since the spring force of the spiral spring 106 is not too strong, the seat back B will stop moving forward on contacting a seat occupant's back. On the other hand, by pushing the seat back B against the force of the spiral spring 106 , the occupant can tilt the seat back rearwards to increase the reclining angle. When the operation lever 126 is released from its upward position, it is returned to the initial position by the spring force of the spring 130 . Then, the pin 136 causes clockwise pivotal movement of the swing lever 143 . As a result, the cam member 139 pivots in the clockwise direction to release the leg 142 from the recess 141 of the tooth member 132 . Therefore, the tooth member 132 pivots counterclockwise to cause engagement between the teeth 134 and 135 . Therefore, the lower arm 102 is locked at the selected position. It should be appreciated that with the shown construction, the seat back reclining mechanism permits reclining adjustment between the neutral position P and a fully reclined position Q . When walk-in mechanism F is to be used for permitting the rear seat passenger to pass therethrough, the operation lever 126 is pulled upwardly or the foot pedal 129 . By this, the operation lever 126 is pivoted about the pivot 310 in clockwise direction. Accordingly, the locking engagement between the teeth 134 and 135 is released. Therefore, the lower arm 102 becomes free from the locking engagement. Therefore, the lower arm 102 is pivoted by means of the spiral spring 106 . As can be appreciated, since the walk-in mechanism F is operable in absence of the seat occupant, the lower arm 102 is inclined or tilted forwardly. At the same time, the pin 105 is pivotally moved along the arc shaped elongated slot 104 of the lower arm 102 . By inclination of the lower arms forwardly, the plate lever 119 comes into contact with the lever section 122 of the walk-in lever 121 for causing latter to pivot in counterclockwise direction. By this, the actuation wire 123 is pulled for a predetermined direction to pull the locking lever 56 in lock releasing position for causing forward shifting the movable rail with the seat structure. On the other hand, when the seat back B is to be placed at the folded position for placing the back side of the seat back substantially in horizontal, the operation lever 126 is initially pulled up to the uppermost position 126a as set forth above for causing forward inclination. At this position, the swing lever 146 is depressed by the pin 116 of the catching lever 111 so as to be maintained in counterclockwise pivoted position. By this, the operation lever 126 is maintained to the uppermost position 126a . On the other hand, the pin 116 of the catching lever 111 comes into contact with the stopper 118 . As a result, the catching lever 11 is slightly pivoted in clounterclockwise direction. Therefore, the locking pin 110 and the locking pin receptable recess 114 of the catching lever 111 which are placed in incomplete engagement state by initially pulling the operation lever 126 in uppermost position 126a , are released. By this, the upper arm 108 becomes free to pivot about the pivot 109 . With the shown construction, the catching lever 111 is designed for slight pivotal movement according to frontwardly tilting movement of the lower arm 102 and maintain the angle between the axes a and b smaller than or equal to 90° , the locking pin 110 becomes easily released from locking engagement with the catching lever 111 . Therefore, despite of the force exerted on the catching lever 111 for depressing the upper arm 108 onto the rubber damper 151 , the operational force required for releasing locking engagement between the locking pin 110 and the catching lever 111 becomes small. By pushing the seat back B frontwardly into the folded position, the upper arm 108 pivots about the pivot 109 in counterclockwise direction. Then, as shown by phantom line in Fig. 9 , the locking engagement between the plate lever 119 and the lever section 122 of the walk-in lever 121 is released. Therefore, the walk-in lever 121 is forced into pivotal motion by the spring force of the spring 154 via the wire 123 , in clockwise direction. Therefore, the walk-in mechanism D is again placed into locking state. Therefore, the movable rail with the seat cushion is locked to the stationary lever at forwardly shifted position. Therefore, the seat placed at the folded position can be stably maintained. For returning the seat back B from the folded position to the normal position, the upper arm 108 with the seat back is pivoted in clockwise direction, as shown in Fig. 7 . The locking pin 10 comes into engagement with the locking pin receptacle recess 114 of the catching lever 111 for causing integrally locking of the lower and upper arms 102 and 108 . Then, the movable rail of the seat slide 152 is shifted rearwardly on the stationary rail. Simultaneously, the tilt angle of the seat back B is adjusted to the desired position in the manner discussed with respect to the operation of the seat back reclining mechanism. As desired, the tooth 135 of the tooth member 132 and the tooth 134 of the lower arm 102 come into engagement. Therefore, the seat back B is fixedly maintained at the selected angular position as illustrated by P . Figs. 10 through 13 shows a seat back hinge structure which is applicable for pivotally supporting the seat back B on the seat cushion A at the side opposite to that where the preferred embodiments of the seat back adjusting mechanism is provided. As shown in Figs. 10 and 11 , a base plate 201 is rigidly fixed on the seat cushion frame. A lower arm 203 is pivotally mounted on the base plate 201 for pivotal movement about a pivot 202 . An upper arm 205 is pivotably connected to the upper end of the lower arm 203 via a pivot 204 . Upper and lower latches 211 and 213 are provided at upper and lower ends of the lower arm 203 . The upper latch 211 is pivotable about a pivot 210 . Similarly, the lower latch 213 is pivotable about a pivot 212 . A link plate 216 is provided between the upper and lower latches 211 and 213 . The link plate 216 pivotable about pivot pins 214 and 215 respectively projecting from the upper and lower latches 211 and 213 . The upper arm 205 is formed with an extension 205a engageable with a recess 211a of the upper latch 211 . The lower latch 213 is formed with a recess 213a for receiving an extension 201a formed on the upper edge of the base plate 201 . The lower latch 213 . The lower latch 213 is designed to place the pivoting center for interengagement between the extension 201a and the recess 213a , and also the lower latch 213 may also be positioned so as to disengage the extension 201a and the recess 213a, as shown in Figs. 10 and 13 . The lower latch 213 is normally biased clockwise by means of a spring 217 . On the other hand, the upper latch 211 is formed with a cut-out 218 . An elastic member 219 , such as a rubber member, is secured in the cut-out 218 . The elastic member 219 projects to contact the side face of the upper arm 205 frictionally. A stopper 220 is provided on the base plate 201 for limiting the pivoting angular of the lower arm 203 . The lower arm 203 is formed with a stopper projection 221 to abut against the stopper 220 . The whole structure of the hinge is covered by a holder 222 . In the shown construction, when the seat back B is operated into the folded position, the lower arm 203 follows pivotal movement of the seat back to be pivoted about the pivot 202 in the counterclockwise direction as seen in Figs. 10 and 13 . Pivotal movement of the lower arm 203 is limited by the abutting of the stopper projection 221 onto the stopper 220 . At this position, the lower latch 213 slides on the guide edge 208 of the base plate 201 to establish engagement between the extension 201a and the recess 213a . At this position, the lower latch 213 pivots about the pivot 212 . By pivotal movement of the lower latch 213 , the link plate 216 drives the upper latch 211 in clockwise direction about the pivot 210 . By this, engagement between the recess 211a and the extension 205a is released. Therefore, the upper arm 205 is pivoted about the pivot 204 to be placed at substantially horizontal position. On the other hand, when the seat back is returned to the normal position, the seat back is pulled in the clockwise direction. Then, the extension 205a of the upper arm 205 comes into engagement with the recess 211a of the upper latch 211 . Therefore, the upper latch 211 pivots about the pivot 210 in the counterclockwise direction. By this, the lower latch 213 is driven to pivot counterclockwise about the pivot 212 via the link plate 216 . Then, the extension 201a of the base place 201 is released from the recess 213a of the lower latch 213 . Therefore, the lower latch 213 becomes movable along the guide edge 208 on the base plate 201 . Therefore, the seat back is maintained at the desired reclining position.

Claims: A hinge structure for an automotive seat which is operable for selecting a seat back (B) reclining position for said seat at a first position, for inclining forwardly for providing space for a passenger to pass thereby at a second position, and for orienting said seat back (B) substantially horizontally at a third position, said hinge structure comprising: a base plate (201) secured to a seat cushion (A) of said automotive seat; a lower arm (203) pivotally mounted on said base plate (201); an upper arm (205) secured to said seat back (B) and pivotably connected to said lower arm (203); and latch means pivotally mounted on said lower arm and engageable with said upper arm (205) and said base plate (201); characterised in that said latch means comprises an upper latch (211) pivotally mounted on said lower arm (203) and engageable with said upper arm (205), a lower latch (213) engageable between said base plate (201) and said lower arm (203), and a link (216) cooperably connecting said upper and lower latches (211, 213); and in that an elastic member (219) is mounted on said upper latch (211) for elastic contact with said upper arm (205). An automotive seat assembly including a seat cushion (A) and a seat back (B), said seat back (B) being operable for selection of a seat back reclining angle in a first position, for forward inclination for allowing passenger access in a second position, and for being oriented in fully forward, substantially horizontal position in a third position, said seat assembly comprising: a base plate (1) fixed to said seat cushion (A); a lower arm (2) pivotably supported on said base plate (1); an operation lever (26); an upper arm (8) rigidly fixed to a seat back (B) of said seat; a locking pin (10) extending from one end of said upper arm (8); and a catching lever (11) pivotably mounted on said lower arm (2) and releasably engaging with said locking pin (10) of said upper arm (8); characterised by said lower arm (2) being biased in a predetermined pivotal direction by a spring (6); said operation lever (26) being provided for pivotal movement with said lower arm (2); by a tooth member (32) cooperable with said operation lever (26) for releasably establishing locking engagement with said lower arm (2); a swing lever (43) for pivotally moving said tooth member (32) for establishing and releasing locking engagement with said lower arm (2); and a link lever (47) associated with said catching lever (11) for causing pivotal movement thereof, said link lever (47) being cooperably connected to said swing lever (42). An automotive seat structure as claimed in claim 2, comprising a walk-in mechanism (F) including seat sliding means (52 - 54) for shifting said seat back and forth, said walk-in mechanism (F) including a seat lock mechanism (55, 56) for locking said seat sliding means (52 - 54), said walk-in mechanism including a walk-in lever (21) associated with said operation lever (26) for synchronizing release of said seat lock mechanism (55, 56) locking said seat sliding means with manual operation of said operation lever (26) for moving said seat back (B) to said second position. An automotive seat structure as claimed in claim 2 or claim 3, comprising an elastic member (51) associated with said second arm (8) active to positionally maintain said second arm (8) by frictional engagement with said first arm when said second arm (8) is not operatively engaged. An automotive seat structure as claimed in any one of claims 2 to 4, wherein said operation lever (26) is integrally formed with a foot pedal (29). An automotive seat structure as claimed in any one of claims 2 to 5, comprising third locking means (119, 122) active to lock said second arm (8) while said seat back (B) is placed at said third position. An automotive seat structure as set forth in claim 2, wherein said operation lever (26) associated with said lower arm (2) for pivotal movement therewith has first and second components selectively operable to a first operational position for releasing engagement of said lock pin (10) and said locking lever (11) for permitting pivotal movement of said upper arm (8) with said seat back (B) into said second position, and at least one of said first and second components being further operable to a second operational position to release locking of said lower arm (2) for establishing said third position of said seat back (B) while engagement between said locking pin (10) and said locking lever (11) is released.

Inventors: IKEGAYA ISAO C O FUJI KIKO COM, KINOSHITA TAKAO C O FUJI KIKO, NAKAMURA SHINYA C O FUJI KIKO, SUGIMOTO KUNIHISA C O FUJI KIK, IKEGAYA, ISAO, C/O FUJI KIKO COMPANY LTD., KINOSHITA, TAKAO, C/O FUJI KIKO COMPANY LTD., NAKAMURA, SHINYA, C/O FUJI KIKO COMPANY LTD., SUGIMOTO, KUNIHISA, C/O FUJI KIKO COMPANY LTD.
Applicants: FUJI KIKO KK, FUJI KIKO COMPANY LIMITED
Application year: 1990
Main classification: B60N2
IPC codes: B60N2