GB2255905A

GB2255905A - Adjustable vehicle seat

Info

Publication number: GB2255905A
Application number: GB9214046A
Authority: GB
Inventors: Hiroshi Sekido; Tadashi Sakuma; Toshimichi Hioki
Original assignee: Okamoto Industries Inc
Current assignee: Okamoto Industries Inc
Priority date: 1989-04-28
Filing date: 1992-07-01
Publication date: 1992-11-25
Anticipated expiration: 2012-07-01
Also published as: KR900015977A; GB2232078A; GB9212246D0; GB2255905B; GB2232078B; JPH0513634Y2; GB9214046D0; GB9009346D0; KR940000035B1; JPH02142329U

Abstract

A vehicle seat A adjustable by air bags 40a includes a pair of x-shaped link motion devices 22 provided between the bottom of a seat portion and the upper surface of a support bed, said link motion devices being adapted to move the seat portion in the vertical direction and to keep the seat portion level as it is raised and lowered; a seat portion lift bellows formed by a plurality of air bags 40a jointed to each other to form a stack and having a plurality of air communicating vents provided at their jointed portions and an air feeding tube jointed with at least one edge of said air bags' periphery to feed compressed air for expanding and contracting said seat portion lift bellows; said bellows being disposed under the bottom of said seat portion to locate said seat portion lift bellows between the pair of x-shaped link motion devices whereby, said seat portion can be raised and lowered by the expansion and contraction of said bellows; and a seat elevation locking device provided to lock the seat portion at a preferable level comprising an L-shaped frame 30, the corner of said L-shaped frame being pivotally connected to the upper surface of said support bed by means of a bracket 32, and consisting of a vertical frame portion 30b and a horizontal frame portion 30a, said vertical frame portion 30b being provided with a rack 30 engagable with a lock pin 17 projecting from the rear end of said seat bottom portion, an elevation lock bellows 33 comprising stacked type air bags 40a between the bottom surface of the free end of said horizontal frame portion and the said upper surface of said support bed, wherein said horizontal frame portion can be moved up and down causing the vertical frame to swing back and forth according to the expansion and contraction of said elevation lock bellows to disengage and engage said rack from and with said lock pin. <IMAGE>

Description

VEHICLE SEAT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a vehicle seat, more particularly to an improved vehicle seat equipped with an adjustment mechanism capable of adjusting and controlling the mobility of the seat in the longitudinal direction, and the like, to an optimized position respectively according to the seat occupant's preference.

2. Description of the Prior Art Conventionally in the art, it is known that there are various types of vehicle seat having automatic mechanisms such as the inflating mechanism of seat contours, the elevating mechanism of seat level, the mobilizing mechanism of seat body in longitudinal direction and the like, and these mechanisms are mainly driven by utilizing the stroke of cylinder such as a hydraulic cylinder, an air cylinder, a motor-drive cylinder and the like under a remote control from the dashboard.

Particularly it is noted that the inflating mechanism of seat contour consists of an inflatable air bag which is housed within the cushion of seat contour and actuated by a pneumatic means. So far as the air bag is concerned, there is no prior art to substitute the stroke of air bag for the stroke of cylinders as mentioned above so that the air bag is limited to be used for only the inflation of seat contours.

However, it is known that the above conventional type automatic vehicle seats are not always popular because of the higher cost of production accompanied with expensive drive sources such as the cylinders and their pumps with motors.

In addition, the total weight of the above mechanism is not negligible for the requirement of reducing the car weight as the needs of the times in view of the energy conservation.

As another disadvantage of the conventional, it is also known that a seat occupant is not always comfortable while sitting on the seat when these cylinders are driven to thrust out their contour pads outwardly or to change their position excessively because such the mechanical change of seat contours or seat position lacks softness with respect to the configuration between the changed seat contour or seat position and the occupant's body due to the metallic construction of those mechanisms.In review of the conventional type prior art, it is found that some of them are not equipped with a complete stopper system to fix the seat body at the changed position by locking the stopper of the seat body automatically in response to the change position of seat body, and then it is presumable that it may be often removed by an external cause such as the sudden stop of car, a car crash and the like, which could create a serious problem as regards the safety of vehicle seat.

SUMMARY OF THE INVENTION Accordingly, a general object of the present invention is to provide an automatic vehicle seat capable of controlling the position of at least one portion of a vehicle seat in which air bags are substituted for air cylinders.

More specific objects of the preferred form of the present invention are: (i) to provide reciprocation mechanisms for the movements of the vehicle seat in which stacked air bags react between a base and an actuating plate to transmit the stroke of air bags to an object in substitution for a conventional type air cylinder; (ii) to provide a seat back, a head-rest, an elevation type seat portion, a thigh-support and to move the seat body movable in longitudinal direction, which are driven independently by air bags; and (iii) to provide an improved type vehicle seat assembly equipped with an automatic mechanism capable of remotely controlling the each portion of vehicle seat, which can be produced at a minimized production cost and with a light weight.

According to the present invention, there is provided a vehicle seat capable of adjustment by air bags and including a pair of x-shaped link motion devices provided between the bottom of a seat portion and the upper surface of a support bed, said link motion devices being adapted to move the seat portion in the vertical direction and to keep the seat portion level as it is raised and lowered; a seat portion lift bellows formed by a plurality of air bags jointed to each other to form a stack and having a plurality of air communicating vents provided at their jointed portions and an air feeding tube jointed with at least one edge of said air bags' periphery to feed a compressed air for expanding and contracting said seat portion lift bellows; said bellows being disposed fixedly in a space under the bottom of said seat portion to locate said seat portion lift bellows between the pair of x-shaped link motion devices whereby, said seat portion can be raised and lowered by the expansion and contraction of said bellows; and a seat elevation locking device provided to lock the seat portion at a preferable level comprising an L-shaped frame, the corner of said L-shaped frame being pivotally connected to the upper surface of said support bed by means of a bracket, and consisting of a vertical frame portion and a horizontal frame portion, said vertical frame portion being provided with a rack engagable with a lock pin projecting from the rear end of said seat bottom portion, an elevation lock bellows comprising stacked type air bags between the bottom surface of the free end of said horizontal frame portion and the said upper surface of said support bed, wherein said horizontal frame portion can be moved up and down causing the vertical frame to swing back and forth according to the expansion and contraction of said elevation lock bellows to disengage and engage said rack from and with said lock pin.

Referring now in detail to the aspect of air bags to be used in the present invention as a substitute, for the conventional hydraulic cylinder, a single body of an air bag may consist of an almost square shaped bag which is made of a plurality of thermo plastic sheets having a high tensile strength. A plurality of sheets is laminated and all the side peripheries of air bag are thermally welded to be sealed. As the final products of air bags, the plurality of air bags are further connected as a stack by joining their central portions of each other face to face with a thermally welding means and a common opening passes through the central portions so that the bags communicate with each other pneumatically and constitute a bellows as a substitute for a cylinder when a compressed air is supplied into the air bags.

This is the final aspect of air bags system.

The air bags have a surface area as large as possible to correspond with the surface area of the bottom of seat portion so that the air bags can lift up the whole seat body together with the occupant easily by a minimum of air pressure such as about 0.1 kg/cm2 (1000 mm H20/cm2). For example, supposing that an air bag has a surface area of 929cm2 (one foot square) and air at a pressure of 0.1 kg/cm2 is supplied to the bag, the liftable load becomes 92.9 kg.

To lift this load using an air cylinder having the inner diameter of 2.54 cm (one inch), the necessary air pressure would be 18.36 kg/cm2 which may be beyond normal air pressure used in industry in general. As can be understood, therefore, 18.36 kg/cm2 of pressure may require a hydraulic cylinder. In contrast, because 0.1 kg/cm2 is such a low pressure a simple air compressor mechanism, even an oscillating type air compressor having a bellows made of plastic material can be used. It is understandable that therefore the air bag system is particularly suitable for the lifting mechanism in comparison with the conventional cylinders.

As a preferable attachment of the seat portion apart from the lifting mechanism, a thigh-support pad is provided at the front edge of seat portion and the thigh-support pad is adjusted automatically so as to move forward or backward by means of the expansion or contraction of air bags as a substitute for an air cylinder and the like.

Embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, wherein Fig. 1 is a longitudinal sectional side view of a vehicle seat of an embodiment of the present invention employing several air bag systems as substitutes for air cylinders; Fig. 2 is an enlarged longitudinal sectional side view of the Fig. 1 seat portion; Fig. 3 is a partially enlarged longitudinal sectional side view of the Fig. 1 seat back portion; Fig. 4 and Fig. 5 are respective transverse sectional views of the side supports provided in the both sides of seat back portion of Fig. 2; Fig. 6 is a transverse sectional view of the side supports provided in the both sides of the Fig. 1 seat portion; Fig. 7 is a transverse sectional top plan view of the Fig. 1 seat back portion;; Fig. 8 is a vertical sectional front view of the Fig. 1 lower portion of the seat; Fig. 9 is a partially broken away side view of the elevation mechanism provided between the seat portion and a base of the seat; Fig. 10 is a side view showing a stopper portion consisting of a toothed member and rack bar for the elevation mechanism; Fig. 11 is a partially broken away side view of the stopper portion and shows an actuator combined with air bags for the elevation mechanism; Fig. 12 is a vertical front view of a stopper for controlling the mobility of the seat body on a rail; Fig. 13 is a transverse top plan view of the stopper of Fig.

12 when engaging a rack on the seat; Fig. 14 is a schematic diagram showning the pneumatic system and control system; Fig. 15 to Fig. 18 are partly broken away perspective illustrations showing the air bags; Fig. 19 is a partly broken schematic illustration showing an air bag made of laminated sheets; Fig. 20 is a partly broken away perspective view of a vehicle seat according to another embodiment of the invention; Fig. 21 and Fig. 22 are enlarged sectional views showing the head-rest portion of the seat of Fig. 20; Fig. 23 is a vertical sectional side view showing a seat body according to another embodiment of the invention; Fig. 24 is a view similar to Fig. 23 showing the seat in a different position; Fig. 25 is a side view for showing a seat according to another embodiment of the invention; Fig. 26 is a side view showing the seat body of Fig. 25 when the seat is elevated;; Fig. 27 is a vertical sectional front view showing the seat body of Fig. 26; Fig. 28 is a vertical sectional side view for showing a seat body according to yet another embodiment of the invention; Fig. 29 is a vertical sectional side view showing the seat body of Fig. 28 in another position; and Fig. 30 is a side view showing the seat body of Fig. 29.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In Figs. 1 and 3, a seat back portion (a) consists of a seat back body (1) and a rear board (2) supporting the seat back body (1). As shown in Fig. 3, the seat back portion (a) further consists of an upper half portion of the seat back defining a head-rest (b) and a lower half portion of seat back. The upper half portion includes an automatically adjustable mechanism to move the head-rest (b).

In the upper half portion, there is a box shaped hollow space, containing an inner case (4), which is provided within the thickness of the upper half portion of seat back body (1), and the top and bottom of the inner case (4) are open.

A cranked lever place (b2) is provided to lie inside the rear wall of the inner case (4) and the upper portion of the lever plate (b2) is fixed to the bottom of a head-rest body (bl).

The lower portion (b2') of the lever plate (b2), which is much longer than the upper portion, is free in the inner case (4) which also holds air bags (11) adjacent the free end of lower portion (b2') as shown in Fig. 1.

The lever plate (b2) is formed with side walls (b2")(b2") which slope from the free end of the corner portion of the lever plate (b2) to reinforce same. A pair of hinge shaft holes (9)(9) are provided at in the side walls (b2")(b2") at the crank of plate (b2) to receive a hinge shaft (10) to enable the lever plate (b2) to be pivoted by expanding to air bags (11) against a vertical interior wall (4a) of the front side of the inner case (4), toward the rear wall of case (4).

By expanding the air bags (11) to pivot the lever plate (b2), the head-rest body (bl) is inclined towards the front of the seat to enhance support of the occupant's head, for example during long distance driving.

A pair of C-shaped springs (12) having an inward bias is provided between the bottom portion of the head-rest body (b1) and a top portion of the case (4) to urge the head rest body (b1) back to the upright position shown in Fig. 1 when the air bags (11) are deflated.

To enable movement of the upper half portion of seat back body (1) another mechanism comprising a cranked lever plate and an air bags system is provided within the lower half portion of seat back body (1).

As shown in Fig. 3, a box shaped hollow space (2a) provided within the thickness of the lower half portion of seat back body (1) has an inner case (4') housed within the hollow space and the top portion of this hollow space is open as indicated by opening (2b). A cranked lever plate (lid) has an upper half portion (le) which projects into the other hollow space (la) of the upper half portion of seat back body (1) and is fixed securely with the interior rear wall of the hollow space (la) by means of screws (not shown in the drawings) of the like.The length of the upper half portion (le) of the lever plate (lid) the length of the other downward half portion (lid') need to be sufficient for supporting the whole body of the upper half portion of seat back body (1) excluding the head-rest body (by). The free end of the downward half portion (lid') is free in the inner case (4').

The lever plate (Id) is bent up at both side edge portions to define side walls (ld")(ld") which slope to fall towards the free end of the lever plate (lid) in order to reinforce same.

A pair of hinge shaft holes (3)(3) are provided in the walls (ld")(ld") where the plate (ld) is cranked to receive a hinge shaft (5). A pair of hinge shaft brackets (2c)(2c) having hinge shaft holes (2c')(2c') are fixed to the walls of the seat back between casings (4) and (4') and are also fixed on the top edge of the opening (2b) in the hollow space (2a) and outwardly from the both side walls (ld")(ld") of the lever plate (ld). Lever plate (ld) is inserted in the side brackets (2c)(2c) to engage these shaft holes (3)(3)(2c')(2c') by passing the shaft (5) into them, and an air bag system (6) is assembled between the downward half plate (lid') and the front side interior wall (4a') of the inner case (4').The upper half portion of the seat back body (1) can therefore be tilted forwards when the air bag system (6) is expanded according to the occupant's preference. In the summary therefore, the seat back body (1) comprises three relatively tiltable parts, namely the headrest body (b1) the upper half portion and the lower half portion and their gradients can be relatively adjusted according to the occupant's preference, by air bag systems which are adopted as substitutes for conventional hydraulic cylinders and the like.

Also shown in Fig. 3, a pair of C-shaped springs (7) having an inward bias are provided between the bottom portion of the upper half portion of seat body (1) and the top portion of the opening (2b) and the free ends of these spring (7) are fixed to said portions respectively so as to urge the upper half portion of seat back body (1) to an upright position unless the air bag system (6) is actuated. The seat back portion (a) is fixed at the rear end of the seat portion (c) of the vehicle seat so as to recline or rise freely, utilizing any well known locking mechanism in the art.

By making the size of inner cases (4)(4'a) in the thickness direction of seat back body larger, the extent of inclining head rest and upper seat portion becomes greater and it may be desirable to enlarge the size of inner case as well as the thickness of seat back body.

In another modification, instead of providing the walls (4'a)(4a) for receiving the expanded air bags there may be independent plates supported by an adequate number of arms extending from the rear side wall.

Reference is now made to Fig. 2, which shows that seat portion (C) has fine mechanism functions namely an inclining mechanism for changing the gradient of seat portion (C), a thigh-support mechanism for reciprocating a thigh-support portion (15) at the front edge of seat portion (C), a further mechanism for changing the gradient of thigh-support portion (15), a lift mechanism for elevating the seat portion (C), and a mobilizing mechanism for displacing the seat portion in the longitudinal direction on a car floor. In each case, an air bag system is used as a drive source as a substitute for a conventional hydraulic cylinder.

In Fig. 2, the seat portion (C) consists of a trim cover (103) with a cushion material (102) forming the contour of the seat portion (C), a support plate (13) to support the seat contour (C), and a pair of pivotal frames (13a)(13a) fixed with the bottom of the support plate (13) at the side edge portions of the plate (13). The rear ends of the frames (13a)(13) are pivoted at the rear end to constitute a hinge to pivot with respect to hinge brackets (not shown in the drawings) fixed on a cover case (C3) as an intermediate base.

An air bag system (16) is disposed between the lifting portion (13a) of the support plate (13) and the surface of the cover case (C3) to enable change in seat gradient of the seat portion (C) depending upon the expansion and contraction of the air bags (16).

The thigh-support mechanism consists of a body (15') including a trim cover sheet (103) covering a cushion (102), a base (15b"), an air bag system (16) for adjusting the gradient of thigh-support body (15), a pair of ram frames (15a)(15a) of the thigh-support body (15) having a bent free end portion (15b') and an upper plate portion (15a'), and a vertical stroke receiving plate (15a") fixed to the other free end of the ram frames (15a)(15a). The cover case (C3) is fixed on a bottom plate (C2) arranged on a main frames (C1) to house the aforementioned plates (15a')(15a") of the thigh-support portion (15). A pair of groove rails (C5)(C5) having a concave shaped section, slidably receive the ram frames (15a)(15a), and a front edge cover (C4) covers the front opening portion of the cover case (C3).In addition, although this is not shown in the drawings, adequate coil springs are stretched to pull between the base (15b") of the thigh-support portion (15) and the bent free end portion (15b') of the ram frames (15a)(15a), and further between the stroke receiving plate (15a") of the ram frames (15a)(15a) and the rear wall of the cover case (C3). These coil springs should be housed in their mechanisms respectively.

As shown in Figs. 7 and 8, to enhance the comfortability of the seat portion and the seat back portion, there are sides support pads (d)(d) which are provided to hold the both sides of occupant's thigh portions in the seat and also to hold the occupant's sides in the seat back during driving of the car.

Fig. 8, shows the symmetrical disposition of the pair of the side supports (d)(d) about the seat portion (C). As shown in Fig. 6, each side support pad (d) is contoured with the side support pad (d) of the seat portion (C), and there is a hollow space provided under the side support pad (d) to house an air bag system (20) arranged in combination with a cranked lever plate (d2) having a pair of sloped side walls, and an outer board (d') with a trim cover sheet, an upper half portion (dl) of the lever plate (d2) fixed to the outer board (d') which is raised together with the pad body (d) when the air system (20) is expanded between a base wall (d3) of the hollow space and the lower half portion (d2) of the lever plate (d2) to press the latter.A pair of hinge shaft holes (18)(18) is provided at the sloped walls of the lever plate (d2) at the cranking thereof to engage by a shaft 19 with a pair of hinge brackets (d4) having shaft holes respectively which are fixed on the outer vertical wall (d4') of the hollow space. As shown in Fig. 4 and 5, the side support pads (d)(d) for the seat back (a) are constructed and arranged to operate in a similar fashion to the side support pads (d)(d) for the seat so that a detailed explanation will be omitted. In addition, these side support pads (d)(d) are constantly pulled outwardly to be opened by stretching a pair of springs (not shown in the drawings) between the base walls (d3)(d3) and support plate (d2).

Reference is now made to an elevation system of the seat body (A) equipped with an automatic lifting mechanism utilizing an air bag system as a substitute for the conventional hydraulic cylinder and the like. As shown in Fig. 1 and in Fig. 26, this elevation system comprises of an intermediate base (21) provided to support the seat body (A) through an X-shaped link mechanism and the air bag system, the X-shaped link mechanism (22)(22) consisting of four bar members (22a)(22a) which cross each other in pairs at a central position where they are pivotally inter connected.A pivotal hole is provided at the each free end of each bar member (22a), and a pair of brackets (23)(23) having pivotal holes are fixed on the front end of the intermediate base (21) and the front end of the bottom surface of the main frame (24) and, another pair of brackets (23')(23') having lateral slits (23a)(23a) and fixed on the rear end of the intermediate base (21) and the rear end of the bottom surface of the main frame (24).

By this means each free end of X-shaped bar members (22a) is pivoted with these brackets (23)(23)(23')(23') in order to constitute a link mechanism to keep the level of seat body (A) constant during the elevating movement of seat body (A) by means of the expansion and contraction of the air bag system (28) which is assembled between the pairs of arms of the link mechanisms. In the link motion of X-shaped link mechanism, the idle slits (23a)(23a) of the brackets (23')(23') are effective to make the pivoted portions of the free ends of bar member (22a) to slide along the slits (23a)(23a) according to the rising movement of the X-shaped link mechanism by the expansion of the air bags (28). The other free ends of the bar member (22a)(22a) remain fixed pivotally with the brackets (23)(23).

Next will be described a mobilizing mechanism for the seat body (A) and its elevation system. Referring to Fig. 1 and Fig. 12, the main frames (24) support the intermediate base (21) of the aforementioned elevation mechanism. The mobilizing mechanism consists of four elements such as the main frames (24)(24) (which a concave shape in cross section to engage with the slide on a rail (27)) which are reciprocated by air bags (29). The rails (27)(27) are combined with racks rail (27a)(27a) which extend outwardly [in Fig. 12 and Fig. 13] and the rails receive the concave shaped main frames (24)(24) by the convex rail portions with a suitable length corresponding to a span capable of moving the seat body (A) in range of a predetermined distance. A lock pin is adapted to engage with the gear of the rack rail (27a) to serve as a stopper which is actuated automatically by air bags (34) of locking device whose operation is synchronized with the mobility of the seat body (A), and the two groups of air bags (29a)(29b) disposed in a space (Y). The groups of air bags (29)(29) are separated by a partition plate (21b) provided between them (Fig. 1). In the detail of locking device, in Fig. 12, the locking device includes an engaging lever plate (31) formed as L-shaped lever plate (31') which consists of a vertical lever plate portion (31a) and a laterally bent lock pin portion (3lib) including a plurality of lock pins (31c) [in Fig. 13] formed at the free end of the laterally bent portion for engaging with the rack gears (27a) of the rack rail (27).A pair of pivotal brackets (31c') are fixed at the lower portion of the lever plate (31') at both sides to co-operate with further pivotal brackets (35)(35) which are fixed with the concave shaped main frames (24) so that by passing through a shaft (36) into each hinge holes (31c')(31c')(35')(35') of the brackets the lever (31') can pivot relative to the frame. The lever plate (31') is arranged parallel to a vertical wall (38) which is arranged to project from the side surface of a support base (37) fixed on the intermediate base so as to cross the rack rail (27a) at right angles. An air bag system (34) for using this locking device is disposed in a space provided between a receiving surface (38') of the vertical wall (38) and the upper arm (31a) of the lever plate (31').A pair of coil springs (39)(39) are arranged around the shaft (36) for biasing the engage lever plate (31') toward the receiving surface (38') of the vertical wall (38).

The pair of the convex shaped rails (27)(27) combined with the rack rail (27a)(27a) are further fixed on a pair of rail bases (26)(26) which are further more fixed on a pair of bottom bases (25)(25) fixed on the car floor (Z).

An automatic locking mechanism similar to that for the mobility of seat body (A), may be used for locking the seat level set by the elevation mechanism. The seat elevation mechanism also requires any locking device to stop the elevation of seat at a preferable position during the operation of the elevation mechanism. This is important for car driver security.

Figs. 9, 10 and 11 show a seat level locking mechanism (17)(30)(33) which comprises an L-shaped lever (30) consisting of a vertical frame (30b) with rack gears (30b') and a horizontal frame portion (30a) engaged at the underside by an air bag system (33) for the seat level locking mechanism only. The vertical frame (30b) is required to have a sufficient length (including the rack gears portion) to be capable of being engaged in the rack gears (30b') by a lock pin (17) projecting from the rear end of the seat base frame.

In Fig. 27 and Fig. 11, the right angle corner portion of the L-shaped lever (30) is pivoted on a U-shaped bracket (32) which is arranged to project from the rear end edge of the intermediate base (21) of the seat body (A). By expansion and contraction of the air bags (33) disposed under the horizontal frame (30a), the vertical frame (30b) can be pivoted for disengaging and engaging the rack gears (30b') with the lock pin (17), wherein the seat elevation can be stopped at a preferable position.

Figs. 15 to 19, indicate the composition of the air bag systems to be adopted in this invention. Fig. 19 shows the essential composition of sheet material (40) of the air bag (40a) (Fig 15 to Fig. 18]. The sheet material (40) is a laminated sheet consisting of three layers, more particularly a net core material (40') sandwiched between two sheets (40")(40"). With respect to the net core material, it is woven from fiber and/or filament having non-expandable properties and a high tensile strength. The fiber and/or filament is made of a synthetic resin such as a polyester resin, a polyamide resin and the like. The diameter of the fiber and/or filament is between 50 and 100 micron and the woven meshes are between 70 and 200 meshes per inch.This core material (40') is sandwiched between two sheets made of a polyurethane resin and the like having rather slightly harder properties for thermal plastic workability. The layers are laminated as a single sheet (40) by means of a well known process in the art.

Regarding the process for making the bag (40a), two sheets (40)(40) having predetermined sizes are overlapped together and thermally welded along the periphery edges of them to form a sealed bag and a plurality of the sealed bags are stacked and then they are further welded partially at their body portions to connect them to each other partially so as to form a bellows as shown in Fig. 16. Before the final welding process, air communicating vents (41) are provided in the welded body portions and also an air feeding tube (42)(46) is provided integrally with one edge of the air bag (40a). By this means when the bags are inflated by compressed air, such each portion which is not welded opens each other and shows a V-shaped valley between them. By the use of such laminated sheet, the air bag is given an excellent elasticity with a good tensile strength.As to the applicability of the air bag systems to the present invention, the air bag systems shown in Fig. 15 may be applied for the head-rest air bags (11), the seat back controlling air bags (6) and the elevation mechanism air bags (28). The air bag systems shown in Fig. 16 may be applied for the thigh-support extrusion air bags (16) and the seat mobility air bag systems (29). The air bag systems shown in Fig. 17 may be applied for each of the side-support air bag systems (20) (seat portion and seat back portion) and the both locking devices air bag systems (33)(34). Lastly, the air bag systems shown in Fig. 18 may be applied for the seat gradient air bag (16) and the side-support air bag (20).

With the above air bag systems, there need not be any restriction with respect to the welding process of bags, the number of bags in a stack it being simply a matter of using the bags to follow the space adequately.

Referring now in detail to the operation of each mechanism, with reference to Fig. 14, a centralized control panel (47) has switch buttons (47a to 47h) of the three position type arranged on the panel surface, and a low pressure type compressor (43) is driven by a DC motor driven in turn by the car battery source. A compressed air distributing pipe line (44) has 12 branch lines, respectively having 12 three-way type solenoid valves (45a to 45L) and the 12 sets of air bag system (29b), (29a), (34), (28), (33), (16), (16), (20), (20), (16), (20), (20), (11) and (6). These valves (29a) to (6) are wired to the control panel (47) respectively switch buttons (47a) to (47h) corresponding to the valves.

The switch buttons are separated into "exhaust position" (a position to exhaust an air from a bag), "close position" (a position to close the appropriate valve) and "open position" (a position to open the valve). The three way valve means that this valve has three paths such as an inlet path, an outlet path and an exhaust path in the air communication.

Now is described a preferred example of the operation with respect to the above arrangement. For the elevation mechanism of the seat portion, it is recalled that the elevation air bag system (28) is disposed in the space (x) provided between the bottom of the seat body (A) and the bed (37) and also the mobility air bags (29a)(29b) are disposed in the space (y) on opposite sides of the partition wall (21b) so that the air bags (29a) are used for moving the seat body (A) towards the front direction and the air bags (29b) are used for moving the seat (A) towards the rear direction. In the general operation of the air bag system, a switch button is turned to "open position", then the compressor (43) sends compressed air into the air bag system through the air feeding tube (42)(46)[Fig. 15] and the compressed air enters the air chambers (40'a) of the bags (40a) passing through the communicating vents (41) wherein the bags (40a) are inflated.

According to the expansion of the air bags (40a), the appropriate portion of the system is moved toward the direction which the air bags (40a) is expanded.

According to the above action of the air bag system, for example, the cranked lever plates such as the plate (lid) which is embedded in the lower half portion (a) of the seat back and lever plate (b2) which is embedded in the upper half portion (1) of the seat back are pressed rearwardly by the expansions of these air bags (6)(11) and then the upper half portion (1) and the head-rest portion (b) are inclined forwardly; depending upon the instruction from the control panel (47).

As to the seat gradient (13), this is changed by the expansion of the air bags (16). In the thigh-support (15), the gradient of the thigh-support pad (15) is controlled by the air bags (16), each side-support (d) provided on each side of the seat portion (C) and each side of the seat back (a) being moved respectively towards the inside direction of the seat portion (C) and the seat back (a). In this way when, these portions reach the preferably poritions, the switch buttons of the control panel (47) are turned to "close position" which stops the feeding of compressed air into each air bag and holds the bags in adjusted position.

In general, when a switch button is turned to "open position", a corresponding valve opens its inlet and outlet paths to an air bag and closes its exhaust path to block the leakage of air from the valve. In contrast, when the switch button is turned to "close position", the valve closes all the paths of inlet, outlet and exhaust.

If, for example, the occupant wishes to incline the upper half portion (a) of the seat back or the head-rest pad (b) toward the rear direction, and also wishes to move the sidesupports (d) outward, in Fig. 14, the switch button (47a) of the half portion (a) or (47b) of the head-rest (b) and the switch buttons (47c)(47e) are turned to "exhaust position", and then these valves close the inlet path and open the outlet and exhaust paths, so that all air contained in those air bags is exhausted to atmosphere and the bags are contracted respectively.

In case of operating the elevation mechanism, the switch button (47g) is turned to "open position", and firstly the valve (45g') of the lock device (30) opens the inlet and outlet paths and closes the exhaust path so that the air bag (33) of the locking device is inflated prior to the inflation of the main air bag (28). This is achieved by the interceptive existence of delay timer arranged between the locking device valve (45g') and the main bag valve (45g).

Upon the completion of disengaging the locking device, the main air bag (28) is caused to expand by opening the inlet and outlet paths and also closing the exhaust path of the valve (45g').

When the elevation reaches a preferable position, the switch button (47g) is turned to "close position" and the the main bag valve (45g) closes all the paths of the inlet, outlet and exhaust so that the air supply into the main bags (28) is stopped. On the other hand, the locking device valve (45g') closes the inlet path only and opens the outlet and exhaust paths to exhaust the air contained within the locking device air bags (33) for engagement of the locking portion of the vertical rack (30b') with lock pin (17). By engaging the locking device, the seat body (A) is secured at the preferable position.

In case of lowering the seat body (A), when the switch button (47g) is turned to "exhaust position", it is specified that the main bag valve (45g) is instructed to open the inlet and outlet paths in a moment (about two seconds) to send the air into the main bags (28) to pressurize it from the control panel (47). This sudden pressurization is purposed to minimize the seat load including the occupants body weight prior to the disengagement of the locking device to facilitate the disengagement smoothly without any excessive load. During the pressurization, the locking device valve (45g) is instructed to open the inlet and outlet paths and close the exhaust path to inflate the bags (33).Upon the completion of disengagement of the locking device, the main bag valve (45g) is further instructed to close the inlet path only and open the outlet and exhaust paths as usual so that the descent of the seat body (A) is achieved. These operational sequences of valves (45g)(45g') are preprogrammed in the circuit of the control panel.

For moving the seat body (A) back and forth, when the switch button (47h) is turned to "open position", the locking device valve (45h') is instructed to open the inlet and outlet paths and close the exhaust path to inflate the locking device bag (34) initially so that the locking device (31b)(27a) is disengaged. After that, due to a delay timer, the forwarding valve (45h') is instructed to open the inlet and outlet paths and close the exhaust path to expand the bags (29a) to forward the seat body (A).

When the seat body (A) reaches the preferable position, the switch button (47h) is turned to "open position", the forwarding valve (45h1) is instructed to close the inlet and outlet paths and open the exhaust path. On the other hand, the locking valve (45h') is instructed to close the inlet path only and open the outlet and exhaust paths to contract the air bag (29b) according to the sequence of instructions of the programme, to lock the seat in the preferable position. When the seat is to be moved backwards. The locking device valve (45h') is instructed to open the inlet and outlet paths and close the exhaust path to inflate the locking device air bag (34) to disengage the locking device (31b)(27a). After that the backing valve (45h2) is instructed to open the inlet and outlet paths and close the exhaust path to inflate the air bags (29b).According to the expansion of the bags (29b), contrary the forwarding air bags (29a) is contracted by exhausting the air from the exhaust path of the valve (45h1).

As a modification, instead of the switch buttons having the three-way positions, however, they may be modified to another type switch. The centralized control panel may be arranged on or around the dashboard of vehicle.

In further modifications, the various side-parts (d) as described herein may be omitted, for example as shown in Figs 20 to 29, and further any structure which is not referred to in the description may be changed to another different structure.

The seat back portion (a) may be of another type, and further the existence of the head-rest portion is optional. Also, the thigh-support (15) may be always not required.

The seat portion (C) need not have the elevation mechanism and mobility mechanisms (as shown in Fig. 23 and Fig. 24), and also the seat portion (C) need not have the elevation mechanism (as shown in Fig. 28 and Fig. 30).

As described in the above, this invention may be practiced or embodied in still other ways without departing from the spirit or essential character thereof. The preferred embodiments described herein are therefore illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all variations which come within the meaning of the claims are intended to be embraced therein.

This application is divided out of application 9009346.9 which claims as an invention and aspect of a vehicle seat of which an embodiment is described herein.

Claims

1. A vehicle seat capable of adjustment by air bags including a pair of x-shaped link motion devices provided between the bottom of a seat portion and the upper surface of a support bed, said link motion devices being adapted to move the seat portion in the vertical direction and to keep the seat portion level as it is raised and lowered; a seat portion lift bellows formed by a plurality of air bags jointed to each other to form a stack and having a plurality of air communicating vents provided at their jointed portions and an air feeding tube jointed with at least one edge of said air bags' periphery to feed a compressed air for expanding and contracting said seat portion lift bellows; said bellows being disposed fixedly in a space under the bottom of said seat portion to locate said seat portion lift bellows between the pair of x-shaped link motion devices whereby, said seat portion can be raised and lowered by the expansion and contraction of said bellows; and a seat elevation locking device provided to lock the seat portion at a preferable level comprising an L-shaped frame, the corner of said L-shaped frame being pivotally connected to the upper surface of said support bed by means of a bracket, and consisting of a vertical frame portion and a horizontal frame portion, said vertical frame portion being provided with a rack engagable with a lock pin projecting from the rear end of said seat bottom portion, an elevation lock bellows comprising stacked type air bags between the bottom surface of the free end of said horizontal frame portion and the said upper surface of said support bed, wherein said horizontal frame portion can be moved up and down causing the vertical frame to swing back and forth according to the expansion and contraction of said elevation lock bellows to disengage and engage said rack from and with said lock pin.

2. A vehicle seat according to claim 1 comprising: a seat back; a cranked head rest adjusting lever plate disposed vertically within the upper end of a seat back for pivotal movement at the bent corner portion of said lever plate so as to define an upper half portion and a lower half portion; the upper half portion of said lever plate being arranged to project upwardly from the said corner portion thereof, the lower half portion of said lever plate being housed within a box shaped cylinder in the seat back; said box shaped cylinder having a rectangular cross section, and being open at the top; the said lower half portion of said lever plate being positioned to be free inside said rectangular cylinder so that the free end of the said lower half portion can swing between both interior walls of said rectangular cylinder; a head-rest pad portion arranged on the said upper end of said seat back, which is fixed to the upper half portion of said lever plate which projects into said head-rest pad portion along a rear wall of said pad portion; and a head rest adjusting bellows formed by a plurality of air bags joined to each other and having air communicating vents provided at their jointed portions and an air feeding tube jointed with at least one edge of said air bags' periphery to feed a compressed air for expanding and contracting said bellows said bellows disposed fixedly between the interior wall of the front side of said rectangular cylinder and the opposed surface of the said lower half portion of said lever plate, whereby the angle of inclination of said head-rest pad portion can be controlled by said bellows type air bags according to the expansion and contraction thereof.

3. A vehicle seat, according to Claim 2, wherein the seat back comprises a lower half seat back and a relatively tiltable upper half seat back, the head-rest pad portion being on the upper end of the upper half seat back; said lower half seat back being equipped with a control mechanism for controlling the angle of the upper half seat back with respect to the lower half seat back and comprising a cranked back rest lever plate, a rectangular cylinder embedded in said lower half seat back within the thickness thereof and back rest adjusting bellows comprising stacked air bags; said back rest lever plate comprising an upper half portion and a lower half portion extending from the cranked corner which is positioned to pivot at the upper end of said seat back, so that said back rest plate upper half portion project upwardly from the said upper end of said lower half portion of said seat back, and said back rest plate lower half portion can swing inside said rectangular cylinder between both interior walls of said rectangular cylinder; said upper half portion of said seat back being jointed upright with the said upper end of said lower half portion of said seat back, and being fixed to the back rest plate upper half portion in that it projects into the body of said upper half portion of said seat back from the bottom thereof and being fixed to a rear wall of the said body of said upper half portion of said seat back; said plurality of air bags forming the back rest adjusting bellows being jointed to each other as a stack and having air communicating vents provided at their jointed portions and an air feeding tube jointed to at least one edge of said air bags' periphery to feed compressed air therein for expanding and contracting said bellows; said back rest adjusting bellows being fixedly disposed between the said interior wall of the front side of said rectangular cylinder and the opposed surface of the said lower half portion of said back rest adjusting lever plate, wherein the said inlinational angle of the said upper half portion of said seat back can be controlled according to the expansion and contraction of said back rest adjusting bellows; said heat rest adjusting lever being in the upper half portion of said seat back, and said head-rest pad portion being jointed with the said upper end of the said upper half portion of said seat back.

4. A vehicle seat according to Claim 2 or 3, including a thigh-support pad with a thigh support adjusting bellows formed by air bags housed therein, said pad being mounted on the outer end of a carrier plate; said carrier being located under the bottom of the seat portion to be moved back and forth horizontally in the outer end of said carrier plate which has in front of the seat portion being bent downwardly and carrying the said thighsupport pad, the other end of said carrier plate providing vertical backplate for displacement by carrier bellows made up of air bags; said thigh adjusting bellows comprising a plurality of air bags stacked together in and disposed between the said bottom of said thigh-support pad and the opposed surface of said bent end of said carrier plate, and serving to control the gradient of said thigh-support pad according to the expansion and contraction of the thigh-support adjusting bellows; and said carrier bellows comprising air bags disposed between said vertical backplate of said carrier plate and the opposed interior wall of a rear side of said seat portion, and being for controlling the back and forth movement of said carrier plate according to the expansion and contraction of said carrier bellows.

5. A vehicle seat according to any of Claims 2 to 4, wherein the several bellows are supplied from a common pressure air supply connected to the bellows by parallel outlet lines which embody control valves controllable from a control circuit operable by the vehicle seat occupant.

6. A vehicle seat according to Claim 6, wherein the control circuit comprises an operation button for each said control valve except that the valves for the lift bellows is inter linked with the valves for the elevation lock bellows so that they operate in sequence, and the valves for the seat displacement bellows are interlinked with the valve for the seat translation locking device bellows so that they operate in sequence.