Abstract:
A steering wheel having a manually adjustable palm swell is disclosed. To accommodate vehicle operators of a wide range of grip sizes, an adjustable palm swell is desired. A steering wheel having a generally hoop shaped core material is covered in thermoplastic resin and then with an outer cover. A bladder assembly is provided within the outer cover. The bladder assembly includes a bladder, a bulb connected to the bladder, the bulb having check valves on its inlet and outlet. The bulb, if depressed successively, causes air to flow into the bladder, thereby increasing the diameter of the steering wheel in the vicinity of the bladder. The bladder assembly further has a relief check valve connected to the bladder, which is manually actuated to allow air to be released from the bladder and decrease the diameter of the steering wheel in the vicinity of the bladder.

Description:
BACKGROUND 
     1. Technical Field 
     The development relates to an adjustable palm swell located within a steering wheel that can be adjusted to provide a comfortable grip to the operator. 
     2. Background Art 
     It is more comfortable for the operator of a vehicle to grip a steering wheel for any period of time when the cross-sectional diameter of the steering wheel is sized appropriately to the hand of the operator. It is known in the prior art to provide a larger diameter in the area where the steering wheel is commonly gripped rather than providing a steering wheel with the greater cross-sectional diameter over the entire circumference of the wheel. However, the size of this larger diameter section, commonly called a palm swell, if fixed in diameter, doesn&#39;t provide the desired comfort for vehicle operators that have significantly larger or smaller grips than the design grip size. 
     SUMMARY 
     The inventor of the present invention has recognized that by providing palm swells, which can be adjusted in size, a greater variability grip size can be accommodated by a single design. 
     A steering wheel is disclosed which has a core material with a thermoplastic resin around the core material, a flexible outer cover over the foam, and a bladder assembly inside the outer cover. The thermoplastic resin can be made from polyurethane, polyvinyl chloride (PVC), polycarbonate, carbon fiber, or any other material known to one skilled in the art. The bladder assembly has a bladder, a bulb coupled to the bladder, and a relief check valve coupled to the bladder. The length of the bladder is roughly a contact length of a human hand along a circumference of the steering wheel when the human hand is grasping the steering wheel, which may be in the range of 4 to 15 centimeters in length. The system further contains a first check valve disposed between the bulb and the bladder and a second check valve disposed on an inlet side of the bulb. In one embodiment, the first and second check valves are duckbill valves. In one embodiment, the bulb and the relief valve are manually actuated, adapted to be actuated by a human digit. In yet another embodiment, the thermoplastic resin applied to the core material is thicker in the vicinity of the bladder, thereby making the cross-sectional diameter of the steering wheel larger in the vicinity of the bladder. In another embodiment, at least two bladder assemblies are disposed within the outer cover. In a typical automotive application, the core material is generally hoop shaped. However, any known shape for a steering wheel, such as a bowtie or W-shaped, is envisioned. 
     An assembly for providing a user-adjustable gripping surface for a user actuator is disclosed which has a bladder disposed beneath an expandable outer covering of the gripping surface of the vehicle, an inlet tube coupled to the bladder, a bulb disposed in the inlet tube, a first check valve disposed in the inlet tube between the bulb and the bladder, a second check valve disposed in the inlet tube on the upstream side of the bulb, an outlet tube from the bladder to atmosphere, and a normally-closed relief valve disposed in the outlet tube. In one non-limiting embodiment, the user actuator is a steering wheel. The steering wheel can be used in an automotive vehicle, a boat, a plane, an off-road vehicle, as examples. The first check valve is normally closed, but opens when pressure within the bulb exceeds pressure within the bladder. The second check valve is normally closed, but opens when atmospheric pressure exceeds the pressure within the bladder and atmospheric air is supplied to the bladder by manually depressing and releasing the bulb. These actions cause the first and second valves to open, respectively. The assembly is mounted at a grip position of the actuator. The relief valve is located at a position accessible by a digit of a hand gripping the user actuator. The user actuator, in one embodiment, is a steering wheel. 
     A method for adjusting a gripping surface in a vehicle is disclosed. By selectively filling and emptying a bladder disposed beneath an outer layer of the gripping surface, the circumference of the gripping surface is selectively increased and decreased, respectively. In one embodiment, selectively filling is accomplished by manually pumping an inflator bulb coupled to the bladder, with the inflator bulb disposed beneath the outer layer of the gripping surface. In one embodiment, the gripping surface is that of a steering wheel of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of a steering wheel in an automotive vehicle; 
         FIG. 2  is a view of the bladder system prior to being installed in a steering wheel; 
         FIG. 3A  is a view of the bladder system as installed in a steering wheel as seen from the driver&#39;s point of view when facing the steering wheel when the bladder is deflated; 
         FIG. 3B  is a view of the bladder system as installed in a steering wheel as seen from the driver&#39;s point of view when facing the steering wheel when the bladder is inflated; 
         FIG. 4  is a view of the bladder system as installed in a steering wheel as viewed from the center of the steering wheel; 
         FIG. 5A  is an illustration of a closed duckbill valve in two orientations. 
         FIG. 5B  is an illustration of an open duckbill valve; and 
         FIG. 6  is a cross-section of a steering wheel at a position of the steering wheel not containing a bladder assembly. 
     
    
    
     DETAILED DESCRIPTION 
     As those of ordinary skill in the art will understand, various features of the embodiments illustrated and described with reference to any one of the Figures may be combined with features illustrated in one or more other Figures to produce alternative embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for particular applications or implementations. The representative embodiments used in the illustrations relate generally to a steering wheel for an automotive vehicle. However, the inflatable bladder may be incorporated into various other types of vehicles and various other types of operator and/or passenger controls, handles, etc. to provide an adjustable grasping or gripping contour. Those of ordinary skill in the art may recognize similar applications or implementations whether or not explicitly described or illustrated. 
     In  FIG. 1 , a portion of an automotive vehicle  8  is shown in which a steering wheel  30  is included. Such a steering wheel  30  is one, non-limiting example application of the present invention. 
     A bladder assembly  10  is shown in  FIG. 2 , having a bladder  12  which is filled by bulb  14 . Duckbill valves  16  and  18  are provided downstream and upstream, respectively, of bulb  14 . Duckbill valves are one-way valves. When bulb  14  is depressed, valve  16  opens, i.e., the two portions of the valve are forced apart allowing air to flow from bulb  14  into bladder  12 . Concurrently, the pressure acting on duckbill valve  18  presses the two portions of valve  18  closed further. Bulb  14  is made of a resilient material such that when no longer depressed, bulb  14  regains it original shape, thereby establishing a slight vacuum in bulb  14 . The vacuum acts upon valve  18  to cause the two portions of the valve to separate allowing external air to enter through valve  18 . Concurrently, the vacuum acting on valve  16  causes the two portions of valve  16  to draw together and remain closed. In this manner, bladder  12  can be pumped up by multiple depressions applied to bulb  14 . 
     Valve  22  is an outlet valve to bladder  12 . When there is a positive pressure in bladder  12 , i.e., when air is forced into bladder  12 , the pressure acting on valve  22  causes it to remain closed. However, button  20 , coupled to relief valve  22 , acts to press apart the two halves of duckbill valve  22  causing it to open under manual control. 
     Valve  22  and bulb  14  are shaped as an ovoid and a sphere, respectively, in  FIG. 2 . Alternative shapes for valve  22  and bulb  14  are contemplated and within the scope of the present invention. 
     Referring to  FIG. 3A , bladder assembly  10  is shown installed within a steering wheel. In particular, the right hand upper side of the steering wheel rim is shown. Another such bladder assembly  10  can be installed in the left hand upper side of the rim of steering wheel  30 . Steering wheel  30  is made up of a solid steel ring (shown in cross-section in  FIG. 6  as element  34 ) with several spokes (not shown) to affix the steering wheel rim to the steering wheel hub (not shown). The ring is covered with a thermoplastic resin or other type of material (shown in cross-section in  FIG. 6  as element  36 ). The thermoplastic resin can be made less dense, and thus lighter weight, by adding a foaming agent into the resin. The resulting material is a non-resilient foam. The term thermoplastic resin, herein, refers to both a thermoplastic resin without an added foaming agent and a thermoplastic resin to which a foaming agent has been added. The thermoplastic resin  36  has a cover  32  on the outside of the steering wheel, which the operator of the vehicle grips. Cover  32  is made of an elastic material to accommodate the expansion of bladder  12 . In one alternative, natural leather is employed. However, in some applications, the extra flexibility of a synthetic material, such as synthetic leather, is employed. 
     In the embodiment shown in  FIG. 3A , when bladder  12  is fully deflated, the circumference of the rim in the vicinity of bladder  12  is nearly the same as in rim sections without a bladder. Alternatively, in the vicinity of bladder  12 , additional thermoplastic resin material is provided so that, even with a fully deflated bladder  12 , a bit of a residual palm swell may exist. In yet a further embodiment, a larger amount of thermoplastic resin is provided in the vicinity of bladder  12  so that even when bladder  12  is fully deflated, there is a modest palm swell. Bulb  14  is mounted in a location which is accessible to an operator&#39;s thumb as steering wheel  30  is grasped. Air can be caused to enter through duckbill valves  18  and  16  by depressing bulb  14 . Depending on the porosity in the vicinity of the opening to valve  18 , it may be found advantageous to provide an aperture  26  to atmosphere through the cover  32  of steering wheel  30  via passageway  24 . If there is sufficient leakage through cover  30  of steering wheel  30  and through the thermoplastic resin within cover  32  of steering wheel  30 , passageway  24  and aperture  26  may be eliminated. To deflate bladder  12 , valve  22  is manually opened by button  20 , which is mounted on the back side of steering wheel  30  in a location that is accessible to the operator&#39;s index finger when grasping the steering wheel. 
     Referring now to  FIG. 3B , bladder  12  is shown fully pumped up. Bladder  12  bulges inwardly toward the hub or center of the steering wheel to form the inner portion of a palm swell. The term “palm swell” is hereby defined to mean a portion of the steering wheel rim (at a designed gripping location) having a generally oval-shaped cross-section, the long axis of the oval parallel with a radius extending outward from the hub of the steering wheel. When a vehicle operator grips the steering wheel  30  at the palm swell, the operator&#39;s fingers wrap around the outer surface of the rim, which remains rigid because the bladder  12  does not extend around the outside surface. This rigid outer portion of the palm swell allows the operator to maintain a firm grip on the steering wheel. The inflated inner portion of the palm swell supports the meaty part of the operator&#39;s palm adjacent the thumb for improved comfort. Because bladder  12  is located only on the inner or hub-facing surface of the rim, the rim does not expand radially outward or toward the operator when the bladder is inflated, and so the palm swell does not have a circular cross-section but rather is generally oval-shaped. The cross-sectional area of the rim of steering wheel  30  in the vicinity of bladder  12  is greater than with a deflated bladder as shown in  FIG. 3A . 
     In  FIG. 4 , the bladder assembly is shown within steering wheel  30  from a view from central hub of the steering wheel looking out to the rim of the steering wheel, as indicated by arrow  33  in  FIG. 3B . As seen in  FIG. 4 , bladder  12  covers only the portion of the rim surface that faces radially inward, toward the steering wheel hub. That is, the bladder does not extend around to the outward-facing surface of the rim. One is unable to determine whether bladder  12  is inflated or not from this angle. From this view, bulb  14  appears as a circle. 
     In  FIG. 5A , duckbill valve  16  is shown in a first orientation in the left illustration. In the right illustration, valve  16  is shown rotated by 90°. In leftmost view, the end of the valve appears rectangular. Valves  16 ,  18 , and  22  are shown in all of  FIGS. 3A ,  3 B, and  4  as being in the configuration at the right of  FIG. 5A  simply for illustration purposes. It should be understood that the actual orientation of the valves in any particular installation may vary, i.e. they may be oriented in a direction similar to that shown in the upper portion of  FIG. 5A , in the lower portion of  FIG. 5A , or some intermediate position not specifically illustrated. Furthermore, the valves in all of  FIGS. 3A ,  3 B,  4 , and  5 A are shown closed. In  FIG. 5B , an open duckbill valve is shown. 
     In  FIG. 6 , a cross-section of a steering wheel  30  is shown. A core  34  is made of a stiff material, such as steel, so that steering wheel  30  retains its shape. Core  34  is covered with a resilient thermoplastic resin  36 , the core and resin thereby forming the rim of steering wheel  30 . Thermoplastic resin  36  has a cover  32  over it. The illustration in  FIG. 6  represents section  6 - 6  of  FIG. 3B . 
     The bladder assembly  10  as shown in  FIGS. 2 ,  3 A,  3 B, and  4  is a non-limiting embodiment of the present disclosure. There are many variations of that embodiment which are contemplated by the inventor of the present disclosure that will be apparent to those of ordinary skill in the art in light of the teachings of the present disclosure whether or not explicitly described or illustrated. For example, pump bulb  14  could be actuated by any digit of the hand, i.e., not limited to be the thumb. Similarly, the button  20  coupled to duckbill relief valve  22  could be actuated by any digit of the hand. The shape of bulb  14  is also non-limiting. Furthermore, any type of one-way valve can be used in place of duckbill valves  16  and  18 . Relief valve  22  can be any valve that can be used for releasing the gases from bladder  12 . The bladder assembly is shown in  FIGS. 2 ,  3 A,  3 B, and  4  as having the inlet and outlet connections near the top of bladder  12 . However, the inlet and outlet connections can be disposed at opposite ends of bladder  12 , or any other alternative location on bladder  12 . 
     While the best mode has been described in detail with respect to particular embodiments, those familiar with the art will recognize various alternative designs and embodiments within the scope of the following claims. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as one skilled in the art is aware, one or more characteristics may be compromised to achieve desired system attributes, which depend on the specific application and implementation. These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. The embodiments described herein that are characterized as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.