Abstract:
A seat which has a pneumatic component. The pneumatic component is pressurized to a desired degree to conform the curvature and hardness of the surface of the seat to the preference of the seat occupant. The pressurization is carried out by manipulating a control mechanism which allows air into and release air from the pneumatic component.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pneumatic seat, viz., a seat having a built-in pneumatic component, and a seat whose seat surface configuration and hardness are adjustably variable as desired. 
     2. Description of the Prior Art 
     Conventionally, seats for a vehicle have a seat portion and a seat back portion which have a surface configuration and hardness suitable for supporting a body of a seat occupant comfortably. However, such surface configuration and hardness are standarized, thus failing to meet varying demands by all possible seat occupants having different body configurations. Moreover, in view of personal preference and for the purpose of helping to eliminate fatigue it may sometimes be desirable to apply pressure to the lumbar portion of the occupant, causing that portion of a seat back which is adapted to support the lumbar portion of the seat occupant to protrude. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a seat comprises a built-in pneumatic component, a built-in pneumatic supply and a control mechanism accessible to the seat occupant which is provided to control the pressure in the pneumatic component to provide the desired support of the seat occupant. 
     Accordingly, an object of the present invention is to provide a seat which provides the desired support of the seat occupant by adjustably varying the configuration and hardness of the seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is further described in connection with the drawings, in which: 
     FIG. 1 is a perspective view of a seat having a built-in pneumatic component, in the form of an air lumbar support, a pneumatic supply in the form of an air pump and a control mechanism to pressurize the pneumatic component; 
     FIG. 2 is a longitudinal sectional view of a seat back portion of the seat shown in FIG. 1; 
     FIG. 3 is a cross sectional view of another embodiment of a pneumatic component; 
     FIG. 4 is a similar view to FIG. 3 showing still another embodiment of a pneumatic component; 
     FIG. 5 is a similar view to FIG. 2 showing an integral seat back construction of a pad and a pneumatic component; 
     FIG. 6 is a similar view to FIG. 5 showing still another seat back construction; 
     FIG. 7 is a cross sectional view of the control mechanism used in FIG. 1; and 
     FIG. 8 is an enlarged fragmentary view of FIG. 7. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1, 2, 7 and 8 of the drawings, the invention is embodied in a vehicle seat having a seat portion 10 and a seat back portion 12. The seat back portion 12 has a built-in elongate pneumatic component 14, in the form of an air bag type lumbar support, oriented horizontally and disposed at a location within a lower half area of the seat back portion 12 which is adapted to support the lumbar portion of the seat occupant. 
     The pneumatic component 14 comprises a rigid base wall 16, a flexible elastomeric top wall 18 extending in opposed relationship with the rigid base wall 16 and fixed to both sides of the latter, and flexible elastomeric bellow like end walls 20, each interconnecting the end of the flexible elastomeric top wall 18 and the end of the rigid base wall 16. As shown in FIG. 2, a dent 22 is formed to surround the pneumatic component 14. The top wall 18 and end walls 20 are made of a rubber or a synthetic rubber. The base wall 16, top wall 18 and end walls 20 cooperate to define an inflatable bag. To expand the elastomeric top wall 18 so as to push up a pad 24 and an outer skin 26 (see FIG. 2) toward the occupant, air is forcibly fed into the interior of the pneumatic component 14. 
     The seat back 12 has an apertured space 28 recessed from the rear side of the seat back to receive an air pump 30 in the form of a rubber bag. The pump 30 is fixedly mounted to the space 28 and communicates with the pneumatic component 14 through a supply hose 32. An exhaust hose 34 branching off the supply hose 32 is coupled with, and thus communicates with, a hollow shaft 36 associated with a manual lever 38. 
     The hollow shaft 36 is supported by a bearing 40 fixed to the seat back 12. One end of the hollow shaft 36 is fixedly received in a bore 42 formed in a base portion 44 of the lever 38, while the opposite end thereof is coupled with the exhaust hose 34. Disposed between the end 46 of the hollow shaft 36 and a shoulder 48 formed in walls of the bore is a valve plate 50 which is adapted to be pressed by air pressure created within the hollow shaft 36 to sealably contact with the shoulder 48, thus preventing air from escaping. Extending axially and outwardly from the bore 42 is a manual button 52 which has a plunger 54 abutting with the valve plate 50. The manual button 52 is biased outwardly by the force of a resilient member in the form of a spring 56. The spring 56 is mounted within a reduced diameter outlet bore 58 and bears against a flange 60 of the manual button 52. Pressing the button 52 against the force of the spring 56 causes disengagement of the valve plate 50 from the shoulder 48, thus allowing air within the hollow shaft 36 to escape outwardly through a clearance between the valve plate 50 and shoulder 48 and through the reduced diameter outlet bore 58 (see FIGS. 7 and 8). 
     Referring to FIG. 7, an arm 62 has one end fixedly mounted to the hollow shaft 36 for integral rotation therewith. The opposite end of the arm 62 is in slideable contact with a plate 64 fixedly secured to the pump 30 (see FIG. 1). The pump 30 includes inlet check valve 30a to allow ambient air into the interior of the pump and an outlet check valve to allow the air into the supply hose 32. 
     With the structure as above, swingably moving the lever 38 through a certain limited angle causes expansion or contraction of the pump 30, thus forcible feeding air through the supply hose 32 to the pneumatic component 14. Therefore, the pneumatic component 14 is inflated to cause the flexible elastomeric top wall 18 to push up the pad 24 and skin 26 toward the occupant, thus helping to relieve the fatigue of the occupant because of the increased pressure applied to the lumbar portion of the body of the occupant. Where it is desired to lower the pressure within the pneumatic component 14, the manual button 52 is pressed to exhaust air. If the manual button 52 is pressed, the valve plate 50 is pressed to disengage from the shoulder 48, thus allowing air within the hollow shaft 36 to escape outwardly. 
     Referring to FIGS. 3 and 4, two alternative embodiments of a pneumatic component are described hereinafter. 
     Referring to FIG. 3, a pneumatic component which is now denoted by 14A has a partition wall 66 of a plate-like rubber therein. The partition wall 66 has its circumference fixedly attached to the inner wall of the pneumatic component 14A at a dent 22 of the pneumatic component 14A. The partition wall 66 may be a plurality of rubber strips or an apertured rubber plate. With this construction, since the partition wall 66 stretches as the pneumatic component 14A is inflated, it acts as means for restraining the deformation of the dent 22 of the pneumatic component 14A, and a strong restoring force is provided, thus allowing the pneumatic component 14A to restore to its original flattened state with a strong restoring force. 
     Alternatively to the use of the partition wall 66, a construction of a pneumatic component 14B as shown in FIG. 4 may be used wherein a spring wire 68 is disposed at a dent 22 to wind around the pneumatic component 14B. Alternatively, the same effect can be obtained if the thickness around a dent 22 is increased. 
     Referring to FIGS. 5 and 6, the same reference numerals as used in FIG. 2 are used to designate like parts. 
     FIG. 5 shows an integral seat back construction of a pad 24 and a pneumatic component 14. In this Figure, a pneumatic component 14 is integrally formed within the pad 24. For forming the pneumatic component 14 integrally within the pad 24, the pneumatic component 14 is placed into a mold and urethane is formed around the pneumatic component 14 by injecting urethane upon forming the pad 24. This construction is advantageous in that relative movement of the pneumatic component 14 with respect to the pad 24 is prevented in use of the pneumatic component 14 and also in that it is suitable for mass production. The pad 24 is also formed with spaces for receiving a supply hose 32 and an air pump 30. 
     Referring to FIG. 6, a pad 24 has an apertured space 70 formed therein to receive a pneumatic component 14. With this construction, the pneumatic component 14 is able to directly push up a skin of the seat, making it easy to manipulate the lever with little force. 
     In the preceding description of the invention, the description has been centered on a seat having a single built-in pneumatic component, but the invention is not limited to this. As shown by phantom lines in FIG. 1, pneumatic components 72, similar to the pneumatic component 14, may be built in the desired portion of a seat to adjustably and independently vary the configuration and hardness of the seat by independently releasing air from the pneumatic component.