Abstract:
An umbrella, shaft, and mounting assembly for an umbrella suitable for use with a wheelchair. The assembly is designed to permit a wheelchair bound person to install, deploy, and retract the umbrella. It is also adapted to permit unobstructed viewing to the front, hands free operation, and a working area to be left to the patron when the umbrella is deployed. It is also designed to permit navigation through portals adapted for wheelchair access. It may also be adapted to facilitate stability in wind and rain.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to wheelchair accessories. It comprises an umbrella and umbrella mounting apparatus which are uniquely adapted and suited for mounting upon a wheelchair such as the one taught in U.S. Pat. No. 6,254,116 issued to the present inventors Thomas Szumlic and Jan Gallagher on Jul. 3, 2001. The umbrella and mounting apparatus are unique both in the apparatus permitting it to be mounted to the wheelchair apparatus as well as in the configuration of the supporting ribs and protective cover of the umbrella which permits coverage of a disabled person confined to a wheelchair.  
         BACKGROUND OF THE INVENTION  
         [0002]    The inventors have previously developed a wheelchair assembly which permits a variety of wheelchair accessories to be attached and utilized for the comfort of a wheelchair patron. These may include comfort accessories or they may include accessories useful in accomplishing certain specific tasks such as photography, eating a meal, reading a book, or writing or drawing on a pad. Such is taught in U.S. Pat. No. 6,254,116, issued on Jul. 3, 2001.  
           [0003]    Designing an umbrella for use by a wheelchair patron poses unique requirements. Typically both hands of the wheelchair patron are required for guiding and powering the movement of the wheelchair. This is particularly true during, the operations of steering or orienting the wheelchair. Additionally, the range of vision of a wheelchair patron may be limited to the area in front of the wheelchair since turning movements may be restricted and the rear view may be obstructed by the wheelchair and accessories. For these reasons it is desirable to develop an umbrella with mounting apparatus for a wheelchair which can be securely placed into position and will securely remain in position without further attention. It is also helpful to permit the area in front of the wheelchair patron to be free of any obstruction to either the wheelchair patron&#39;s view or to an immediate working area which could be used for comfort or recreational functions such as eating, reading, writing, or drawing. To have the ability to free both hands and to have this degree of vision and maneuverability would be a significant benefit to a wheelchair patron.  
           [0004]    The inventors have previously developed, in U.S. Pat. No. 6,254,116 wheelchair accessory mount to facilitate the conduct of a variety of tasks. While it was considered that an umbrella might be mounted upon such an assembly, no structure was shown or taught which was adequate for this task. The accessory mount previously disclosed may be adapted to receive a variety of useful accessories.  
           [0005]    One helpful accessory is an umbrella. Such would provide the ability to provide reliable cover for the wheelchair patron from either sun exposure or from a rain. It would also be helpful if the wheelchair patron could install, adjust, and retrieve an umbrella without assistance. These functions normally require the use of one or both hands of the wheelchair patron or, alternatively, could require the assistance of an attendant.  
           [0006]    These conditions would preclude the use of a standard umbrella. Accordingly, it would be helpful to develop an umbrella which may be placed into and held in position to protect the wheelchair patron.  
           [0007]    Another problem encountered by a wheelchair patron in this endeavor is the need to have a clear range of vision. For instance, if an umbrella shaft were disposed near the center of the wheelchair&#39;s “footprint” against the ground, the umbrella shaft would be positioned precisely in front of the wheelchair patron&#39;s face. This would clearly be uncomfortable and not conducive to the convenience of a wheelchair patron. Such positioning would also interfere with the physical space in front of the wheelchair patron and either prohibit or complicate simple tasks, such as eating, reading, writing or drawing.  
           [0008]    Additionally, when a person is seated in a wheelchair the umbrella coverage must be adapted to cover a greater area since the wheelchair patron will be seated and at least a portion of the wheelchair patron&#39;s legs will be extended out to the front of the wheelchair patron. Additionally, the wheelchair patron will be less able to maneuver or conform to the area of umbrella coverage by manipulating the handle and disposition of the umbrella cover for optimal protection or by aligning the position of his or her own body to conform with the coverage area. Accordingly, an irregularly shaped umbrella cover, such as an elipse, would be helpful.  
           [0009]    It should also be considered that the rain giving rise to the need of an umbrella is frequently accompanied with some measure of wind. An umbrella is particularly susceptible to wind because it tends to behave much like a sail due to its large surface area coupled with its light weight and broad exposure to the elements. The same properties of an umbrella which catch and deflect falling water cause it to catch and channel the wind. Accordingly, if an umbrella is to be used in a “hands free” environment, some means of stabilizing the umbrella through some reasonable measure of wind is necessary. Storms which are more severe are not suitable for umbrella protection even by those not confined to wheelchairs since the wind would push the raindrops into the area of intended umbrella coverage.  
           [0010]    Another matter of concern is satisfaction of the requirements for access imposed by the American with Disabilities Act (ADA). As a wheelchair patron may frequently need to negotiate gateways and doorways with an open umbrella, it is desirable to have an umbrella and wheelchair assembly which can pass through standard entry and exit portals. A standard umbrella normally will not accomplish this.  
           [0011]    Certain previous inventions have taught the use of elliptical or other irregularly shaped umbrella covers. For instance, U.S. Pat. No. 3,042,055, issued to Todorovic on Jul. 3, 1962 teaches an elliptical umbrella with an off-center shaft. The umbrella cover of Todorovic is supported by a radial array of single member ribs. The elliptical shape of the cover is achieved by telescoping the shorter ribs to contract more than the longer ribs. Since the area of coverage is dictated by the longer ribs (which are rigid) the length of the shaft must be at least long enough to accommodate them and, while the umbrella does offer the advantage of unique coverage, it can only be used in conjunction with an umbrella shaft long enough to accommodate the longest ribs. Additionally, the telescoping ribs could jam or malfunction and require some means of restricting the range of sliding in order to achieve rigidity for the umbrella support.  
           [0012]    A very early invention used to achieve unique umbrella coverage was U.S. Pat. No. 229,685, issued to Ege on Jul. 6, 1880. The unique umbrella coverage was achieved by the use of integral support ribs of different lengths. This configuration achieves adequate rigidity but also required the use of a long shaft. It also required the use of a long sliding sleeve for supporting the ribs from the shaft since the longer and integral ribs required extended movement for opening and retracting the umbrella cover.  
           [0013]    Similarly, U.S. Pat. No. 229,752, issued to Ray (coincidentally on Jul. 6, 1880, the same day as Ege) teaches an elliptical umbrella with primary support ribs of different lengths and secondary support ribs of very short lengths for the purpose of allowing a sharp drop of the umbrella around the outer edge, presumably to facilitate improved coverage. The drawings of Ray do not depict the retraction mechanism, but it is obvious that they are subject to the same limitations as Ege with respect to shaft length since the primary support ribs are of different lengths.  
           [0014]    Another more recent effort is U.S. Pat. No. 2,948,289, issued to Owczarek, on Aug. 9, 1960. This invention achieves a unique coverage area by the use of a plurality of ribs from each support rib. The invention teaches the use of various arrays of 4 or more linked ribs in each radial extension but, unfortunately, does not teach or usefully describe the mechanism for opening and retracting the umbrella nor does it describe how the various ribs of each radial extension are linked.  
           [0015]    There are few, if any, inventions which teach a means and method of releasably securing an umbrella shaft in a fixed position. There are no such inventions which teach a means and apparatus for the securing an umbrella shaft to a wheelchair, particularly in order to accomplish coverage of a seating area or a similar elliptical or irregularly shaped umbrella coverage area.  
           [0016]    Accordingly, what is needed, but not provided, by the prior art is a means and apparatus for securing an umbrella assembly upon a wheelchair to permit a seated and immobile wheelchair patron to experience the coverage of an umbrella without using his or her hands other than to put the umbrella into position. It would additionally be useful to develop such a means and apparatus which would enable some measure of positioning and securing the umbrella for the comfort and convenience of a wheelchair patron. It would additionally be useful to provide means and apparatus for a wheelchair patron to experience the coverage of an umbrella while having hands free to accomplish hygiene, recreational, or constructive tasks. It would also be useful to provide such an umbrella and umbrella mounting apparatus which could be used by a wheelchair patron with little or no assistance and will permit entry and exit through standard doors and gates.  
         SUMMARY OF THE INVENTION  
         [0017]    The inventors have developed an umbrella and support assembly which will permit a wheelchair patron to install an umbrella into position and still permit the wheelchair patron use of both hands. The umbrella and support assembly taught herein is also adapted to provide an area of umbrella coverage suitable for covering a wheelchair patron who is seated in a wheelchair and will remain secure in position in the event of non-catastrophic wind and rain.  
           [0018]    This configuration is achieved by providing an umbrella and umbrella support assembly which are adapted with an angled mounting member suitable for mounting upon a wheelchair accessory mount such as the one taught by the present inventors in U.S. Pat. No. 6,254,116. The umbrella and umbrella support assembly are further adapted with an umbrella cover, supporting ribs, and an umbrella shaft which will provide coverage over an irregular and generally elliptical area rather than in a typical circular area of coverage. The apparatus may also be adapted for use with other irregularly-shaped umbrella cover configuration.  
           [0019]    The umbrella apparatus may also be augmented with a stabilizing strap. Such a strap may be a simple device with a means for attaching it to the shaft of the umbrella and then tying or otherwise securing the strap ends to secure points on the wheelchair, such as the armrests. Velcro (R) could be used for the strap ends and a hook or other loop could be used to secure the middle of the strap to the umbrella shaft.  
           [0020]    The “footprint” of the umbrella coverage area (which is narrow across the breadth of the chair and then extends a greater distance from front to back) facilitates the use of the wheelchair and umbrella apparatus in ADA facilities. This is because such facilities are adapted with doorways or portals of adequate width to accommodate a wheelchair and the present apparatus is designed to maintain such dimension, even when extended.  
           [0021]    It is, then, an object of the present invention to provide a means and apparatus for mounting an umbrella support assembly to a wheelchair adapted with an accessory mount.  
           [0022]    It is a further object of the present invention to provide such an umbrella and umbrella support assembly which may be adjusted to some extent in both height and distance from the wheelchair accessory mount.  
           [0023]    It is a further object of the present invention to provide such an umbrella and umbrella support assembly which will permit coverage of the area occupied by a wheelchair patron who is seated in the wheelchair from a shaft which is to either side of the wheelchair patron and slightly to the front of the wheelchair patron.  
           [0024]    It is a further object of the present inventor to provide such an umbrella and umbrella support assembly which may be installed, adjusted, retracted and removed by a wheelchair patron with little or no assistance.  
           [0025]    It is a further object of the present invention to provide such a wheelchair and umbrella assembly which will permit entry and exit through stand doors and gates without retraction.  
           [0026]    It is a further object of the present invention to provide such a wheelchair and umbrella apparatus which will permit a wheelchair patron to have hands free while being covered by an umbrella.  
           [0027]    Other features and advantages of the present invention will be apparent from the following description in which the preferred embodiments have been set forth in conjunction with the accompanying drawings. The present invention should be deemed to be for the purpose of accomplishing each such additional feature or objective. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    In describing the preferred embodiments of the invention reference will be made to the series of figures and drawings briefly described below.  
         [0029]    [0029]FIG. 1 depicts a wheelchair mounted umbrella opened over a wheelchair patron from the top, further depicting the coverage area.  
         [0030]    [0030]FIG. 2 depicts the wheelchair umbrella and mount in isolation, showing the general relationship of its constituent parts.  
         [0031]    [0031]FIG. 3 depicts the components of the device from the side.  
         [0032]    [0032]FIG. 4 depicts the upper portion of an opened umbrella, generally depicting the rib mechanism for supporting an opened umbrella.  
         [0033]    [0033]FIG. 5 depicts the umbrella support rib assembly as it is partially opened, or as it would be while midway in the process of either opening or retracting the umbrella.  
         [0034]    [0034]FIG. 6 depicts a close-up view of the support ribs, further depicting how they work together.  
         [0035]    [0035]FIG. 7 depicts a pivoting rib assembly showing how the rib members move in communication with each other.  
         [0036]    [0036]FIG. 8 depicts a closeup view of a rib assembly pivot member from the side.  
         [0037]    [0037]FIG. 9 depicts a closeup view of a rib assembly pivot from above pivoting joint.  
         [0038]    [0038]FIG. 10 depicts the upper ring assembly from which the umbrella support ribs may be opened.  
         [0039]    [0039]FIG. 11 depicts the shaft and sleeve mechanism which may be used to open and close the umbrella.  
         [0040]    [0040]FIG. 12 depicts a closeup of the umbrella shaft with the sleeve pushed up into the open position.  
         [0041]    [0041]FIG. 13 depicts, in isolation, the mounting handle member. 
     
    
       [0042]    While certain drawings have been provided in order to teach the principles and operation of the present invention, it should be understood that, in the detailed description which follows, reference may be made to components or apparatus which are not included in the drawings. Such components and apparatus should be considered as part of the description, even if not included in such a drawing. Likewise, the drawings may include an element, structure, or mechanism which is not described in the textual description of the invention which follows. The invention and description should also be understood to include such a mechanism, component, or element which is depicted in the drawing but not specifically described.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0043]    Reference will now be made in detail to the present preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention defined in the appended claims.  
         [0044]    While the following description will seek to improve understanding of the invention by describing the various components and elements, it should be considered that certain apparatus may be sufficiently and adequately explained by the accompanying drawings, which are filly incorporated herein, and not require further description. All such apparatus should be considered as part of the specification of the invention for all purposes.  
         [0045]    Making reference first to FIG. 1, it can be seen that a generally elliptical umbrella cover ( 10 ) may be used to provide full coverage to a wheelchair patron ( 101 ) and that such may be supported by an umbrella shaft ( 20 ) which is to one side of the wheelchair ( 100 ). This permits a wheelchair patron ( 101 ) to be covered without obstruction to the forward view (generally,  110 ) or to a accessible working area (generally  111 ) in front of the wheelchair patron ( 101 ).  
         [0046]    Now making reference to FIG. 2, it can be seen that the present invention comprises an umbrella which may be received by an accessory mount such as taught in U.S. Pat. No. 6,254,116 or by other mounts similarly displaced and designed, as further adapted by the invention taught herein. Such similar mounts and adaptations are meant to be included within the spirit and scope of the present invention.  
         [0047]    Making reference to FIG. 13, it can be seen that in order to be received by an appropriate mount (generally  30 ) the umbrella ( 60 ) and support assembly ( 40 ) according to the present invention are adapted with a mounting member ( 50 ) in a position where a standard umbrella would have a handle. This mounting member ( 30 ) receives the shaft ( 41 ) of the umbrella ( 60 ) on one end, bends s through an angle of approximately 45 degrees, and is adapted with a protruding shaft member ( 31 ) on the other end. This protruding shaft member ( 31 ) may be received by the mounting apparatus ( 130 ) of the wheelchair accessory mount ( 131 ) and then may be secured therein by securing means ( 132 ).  
         [0048]    It should be noted that the umbrella cover ( 10 ), in order to provide the wheelchair patron person with adequate visibility and maneuverability, must be irregular in shape. A generally elliptical shape achieves such a purpose. This permits the umbrella ( 60 ) to be supported by a shaft ( 20 ) well-off of the center of coverage and still accomplish the task of adequately covering a patron ( 101 ) confined to the wheelchair (generally,  100 ). While an elliptical shape is taught in the preferred embodiment of the present invention, other irregular (or non-circular) shapes may be used. Such additional shapes should be seen as keeping within the spirit and scope of the present invention. The point of the invention is to afford coverage of the wheelchair patron ( 101 ) from a shaft ( 20 ) to either side. Any shape which will permit this is acceptable.  
         [0049]    In order to accomplish this the umbrella cover ( 10 ) is extended out by a pattern of primary ribs ( 22 ) of equal length and secondary ribs ( 23 ,  24 ,  25 ) of varying lengths so that longer secondary ribs ( 23 ) protrude out from the shaft ( 20 ) in a direction opposite ( 71 ) from the side ( 72 ) of the umbrella mounting member ( 30 ) which is attached to the wheelchair accessory mount ( 131 ). In this manner the umbrella cover ( 10 ) may be expanded out far enough to cover a patron ( 101 ) sitting within the wheelchair ( 100 ) and to keep such patron ( 101 ) generally within the central area of coverage (generally,  102 ) afforded by the umbrella cover ( 10 ).  
         [0050]    The shortest secondary ribs ( 25 ) protrude out from the umbrella shaft ( 20 ) generally opposite from the longer secondary ribs ( 23 ). Both the primary ribs ( 22 ) and secondary ribs ( 23 , 24 , 25 ) protrude out generally perpendicularly and radically from the umbrella shaft ( 20 ). They are of sufficient length to insure front and rear coverage of a person seated within the wheelchair.  
         [0051]    Of course, as is depicted in the prior art, there are a variety of means of accomplishing the provision of an irregular or elliptically shaped umbrella coverage area. Not separately depicted, but easily envisioned from the present figures would be a combination wherein the primary ribs may be of different lengths and further in which some of the primary ribs act alone and without the need for secondary ribs. Such unaccompanied primary ribs would be used to provide the coverage over the “short” side of the umbrella shaft or, in other words, the coverage over the side of the wheelchair upon which the shaft is mounted.  
         [0052]    Additional means of supporting such an umbrella cover are available and too numerous to discuss and describe herein. Each such alternative way of supporting an irregular or elliptically shaped umbrella cover should be seen as keeping within the spirit and scope as well as the claims of the present invention.  
         [0053]    The connection between the umbrella shaft mounting member ( 30 ) and the wheelchair mounting means ( 130 ) may be accomplished in several different ways. What is important is that a secure and firm mount is achieved. This can be done by having either a male protruding member from the umbrella shaft mounting member be received by the wheelchair mounting member or by having a female cylindrical cavity be received by the wheelchair mounting for turning member.  
         [0054]    Accordingly, the umbrella mount assembly could be adapted to permit the mounting of the umbrella in one of several different levels of distance from the wheelchair mount. Alternatively, the assembly could be adapted to be mounted in only one vertical orientation from the wheelchair mount. It may also be desirable to have a means of adjusting the height of the opened umbrella over the wheelchair patron. This could be simply accomplished by providing a channel ( 161 ) through which the umbrella shaft ( 20 ) may be passed to a desired point and then securely fastened in place.  
         [0055]    [0055]FIG. 13 depicts such a mechanism. It can be seen that the umbrella shaft ( 20 ) is snugly received by a channel ( 33 ) through the interior of the umbrella mounting member ( 30 ). A tightening screw ( 34 ) turns within a threaded cylinder ( 35 ) which extends from the surface ( 36 ) of the umbrella mounting member ( 30 ) and is perpendicular to the umbrella mounting member channel ( 37 ). The tightening screw ( 34 ) can be turned by the wheelchair patron ( 101 ) by means of a turning flange ( 38 ) until it is sufficiently tight to hold the umbrella shaft ( 20 ) into place.  
         [0056]    A wheelchair patron ( 101 ) can then grasp and loosen the tightening screw is ( 34 ), position the umbrella shaft ( 20 ) to the proper position, and then grasp and tighten the tightening screw ( 34 .) so as to lock the umbrella shaft ( 20 ) into the desired position. This operation requires two hands, but once completed the umbrella ( 60 ) is securely positioned and leaves both hands of the wheelchair patron ( 101 ) free.  
         [0057]    It should be noted that there are a variety of methods and means of adjusting the position of a shaft in a channel such as used in the present invention. The tightening screw ( 34 ) and channel ( 37 ) combination has been described in the preferred embodiment for several reasons. For one, the adjustments can all be made at or near the mounting member ( 30 ) which is easily within the reach of the wheelchair patron. Another reason is that the umbrella ( 60 ) is large and may be placed under stress by wind and rain. Accordingly, it is desirable to select a means and apparatus which allows the use of an integral shaft with strong composition. This task is made more achievable by the recent development of greatly improved metals and alloys, such as titanium and graphite, which offer improved strength and rigidity without significantly adding to the weight of the apparatus. While such materials are mentioned for these properties, it is not meant to, in any way, designate or limit the materials which may be used. Such materials are only referenced as a means of enhancing the operation of the present invention, which is based solely upon the structure and relationship of the described components. Such components may be made of any acceptable material.  
         [0058]    It may also be possible to utilize a telescoping shaft or a sleeve member which locks onto a lower and upper shaft members and allows select the positioning of the shaft through a series of corresponding holes through the sleeve and upper and lower members which are held in two desired positions with cotter pins. Such a cotter pin arrangement may also be used with the mounting member. Since such structure is well known, it is not separately depicted by drawing, but is intended to be included within the spirit and scope of the present claims.  
         [0059]    It should also be considered that it may be important to insure the proper radial orientation of the umbrella shaft ( 20 ) because of the elliptical shape of the umbrella cover ( 10 ). For this reason, it may be desirable to use corresponding, non-circular or other irregular shapes for the respective umbrella shaft ( 20 ) and mounting channel ( 37 ) so that the umbrella shaft ( 20 ) will always be properly oriented and will not be free to rotate within the mounting member channel ( 37 ). This orientation function could be achieved with a variety of methods and apparatus for establishing and maintaining a desired orientation between a sliding shaft and a receiving channel. For instance, the shaft could be adapted with a protruding member along its line which would correspond with and slide within a slot along the line of a channel. This would establish and maintain a desired relationship between the shaft and the channel. Other alternatives for the tasks of both positioning the height and orientation of the umbrella may be used. Each such alternative should be seen as keeping within the spirit and scope of the present invention.  
         [0060]    It is easy to see that the configurations of male-female receiving members could be reversed as to each component with the same results as described above. It is also easy to see that other simple mechanical structures could be used to achieve the same or substantially similar results of providing a secure umbrella shaft mount which may be manipulated by a wheelchair bound patron. What is important for the purposes of the present invention is that the mounting point is one which facilitates grasping by the hand of a wheelchair patron, may be used and manipulated within reach and without tools, and results in a stable mount. The ability to adjust height and position are and should be seen as alternatives to these features.  
         [0061]    Each such alternative means of providing these functions as well as in the additional and optional functions and features should be seen as keeping within the scope and spirit of the present invention and its claims.  
         [0062]    The function of the umbrella cover ( 10 ) and umbrella rib assembly (generally,  61 ) is also critical to the operation of the present invention. It is necessary for the umbrella shaft ( 20 ) to be set off from the center of the area of umbrella coverage since the shaft ( 20 ) must not be in a position to obstruct either the view of or the area immediately to the front of the wheelchair patron. Accordingly, the umbrella cover may be of a generally elliptical shape but will almost always be irregular, or non-circular. In order to achieve both the unique closing of the umbrella and to ensure adequate coverage of the wheelchair patron the shaft and rib assembly are modified from a typical circular umbrella pattern. While there may be a variety of means and apparatus for such an umbrella rib and cover assembly, the preferred embodiment teaches the use of a system of equal length primary ribs from which are extended secondary ribs of varying lengths. In describing this preferred embodiment reference will be made to FIGS. 4 through 9.  
         [0063]    As depicted in FIGS. 4, 5, and  6 , the umbrella cover support mechanism is adapted with a series of primary support ribs ( 22 ) and secondary support ribs ( 23 ,  24 ,  25 ). The primary support ribs ( 22 ) are each pivotally attached to a ring ( 33 ) at the top ( 34 ) of the umbrella shaft ( 20 ). The ring ( 33 ) is more fully depicted at FIG. 10. The ring ( 33 ) permits the primary support ribs ( 22 ) to pivot from a position wherein they are, in the retracted position (Figure b), folded into and rest parallel to the umbrella shaft ( 20 ) and, in the opened position (Figure a), extend out almost perpendicular to the umbrella shaft ( 20 ). The primary support ribs ( 22 ) will normally number at least six and are circumferentially positioned and arranged about the umbrella shaft from the upper ring ( 33 ) so that they may pivot out to extend radially around the umbrella shaft ( 20 ). While normally six primary ribs are used, either a greater or smaller plurality of primary ribs may be necessary to serve this function. The member of ribs should not be seen as crucial to the invention.  
         [0064]    Each primary support rib ( 22 ) is also pivotally attached, at a point near its outer end ( 26 ) to a lower support rib ( 27 ). The lower support rib ( 27 ) is also pivotally attached to a lower support sleeve ( 70 ) which may slide along a portion ( 71 ) of the length of the umbrella shaft ( 20 ). In this manner, the primary support ribs ( 22 ) may be supported by the lower support ribs ( 27 ) in the open or extended position, by sliding the sleeve ( 70 ) to its upper position ( 74 ), or the primary support ribs ( 22 ) may be allowed to retract by sliding the sleeve ( 70 ) to its lower position ( 75 ).  
         [0065]    The outward end ( 26 ) of each primary support rib ( 22 ) is joined to a secondary support rib ( 23 ,  24 ,  25 ) which is free to pivot to some degree from the primary support rib ( 22 ). This pivotal connection may be made from a point ( 28 ) near the outward end ( 29 ) of such lower support rib ( 22 ). The lower support ribs ( 27 ) each pivotally connect with a lower umbrella shaft ring ( 76 ) which is mounted to and is also free to slide along with the sleeve ( 70 ) about the umbrella shaft ( 20 ). The range of permissible motion of the lower umbrella shaft ring ( 76 ) is from a point ( 77 ) which will allow the primary support rib ( 22 ) and lower support rib ( 27 ) to each be substantially folded against the umbrella shaft ( 27 ) to a point ( 78 ) wherein the primary support rib ( 22 ) and lower support ribs ( 27 ) are outwardly extended from the upper ring ( 20 ).  
         [0066]    The secondary support ribs ( 23 ,  24 ,  25 ) are the means for providing support to an umbrella cover ( 10 ) of elliptical (or other irregular shape) from an umbrella shaft ( 20 ) which is positioned at a point off the center of the area of coverage and to a side of the wheelchair patron ( 101 ). Unlike the primary support ribs ( 22 ) which are of equal length, the secondary support ribs ( 23 ,  24 ,  25 ) generally extend radically out from the primary support ribs ( 22 ) and are of varied lengths. They are supported by a pivotal connection ( 81 ) to each primary support rib ( 22 ) and a two member ( 82 ,  83 ) pivotal connection to each corresponding lower support rib ( 27 ). In this manner, each secondary support rib ( 23 ,  24 , or  25 ) can, along with each primary support rib ( 22 ) be opened to extend out radially from the umbrella shaft ( 20 ) or retracted to hang generally parallel to the umbrella shaft ( 20 ).  
         [0067]    [0067]FIG. 9 depicts how the various secondary rib members ( 23 ,  24 , and  25 ) may pivot with respect to the upper and lower support ribs ( 22  and  27 ). A pivot anchor ( 91 ) may be mounted upon the secondary rib member ( 23 ,  24 , or  25 ) from which the corresponding rib member ( 22  or  27 ) will pivot. The pivot anchor ( 91 ) will have two sides and will be further adapted with an axle member ( 92 ) which may be received by a pivot hole ( 93 ) near the end of a desired pivoting rib ( 23 ,  24 ,  25 ). In order to enhance both the reach and stability of the extension of the secondary ribs ( 23 ,  24 , and  25 ), this mechanism could be housed within a pivot channel ( 95 ) with two such pivot points (generally  96 ). In this case the inner end ( 97 ) of the secondary rib members ( 23 ,  24 , or  25 ), will be adapted with a shaped portion ( 98 ) for fitting within the pivot channel ( 95 ). Separate pivot elbow members ( 99 ) would be used to facilitate the pivot connections (generally  96 ).  
         [0068]    It can now be seen that an umbrella cover ( 10 ) of elliptical, or other irregular shape, may be supported by selecting secondary ribs ( 23 ,  24 , or  25 ) of desired lengths. By placing long secondary ribs ( 23 ) on a side ( 91 ) of the umbrella shaft ( 21 ) to be covered and short secondary ribs ( 25 ) on the other side ( 92 ) of the umbrella shaft ( 20 ) an area of coverage can be provided by an umbrella cover ( 10 ) which is supported by an umbrella shaft ( 20 ) which is well off of the center of the area of coverage and to the side of a wheelchair patron.  
         [0069]    An umbrella cover ( 10 ) may then be secured, by a series of appropriately positioned cover sleeves ( 86 ), over each primary rib ( 22 ) and secondary rib ( 23 ,  24 , or  25 ) so that, when opened out, it will provide adequate and precise coverage and, when closed or retracted, it can be secured about the umbrella shaft ( 20 ).  
         [0070]    It should be noted that there are a variety of known ways to secure an umbrella cover to a series of cover-supporting ribs. It is not the intent of the present invention to either teach or claim the technology associated with the function of securing the umbrella cover to cover-supporting ribs. Indeed, the present invention may be successfully used with a variety of configurations for supporting an umbrella cover with supporting ribs.  
         [0071]    It should also be considered that it may be important to ensure the proper radial orientation of the umbrella shaft because of the elliptical shape of the umbrella. For this reason, it may be desirous to corresponding, non-circular shapes for the respective umbrella shaft and mounting channel so that the umbrella shaft will always be properly oriented and will not be free to rotate within the mounting member channel.  
         [0072]    This same task could also be achieved with a variety of methods and apparatus for establishing and maintaining a desired orientation between a sliding shaft and a receiving channel. For instance, the shaft could be adapted with a protruding member along its length which would correspond with and slide within a slot along the length of a channel. This would establish maintain a desired relationship between the shaft and the channel. Other alternatives for the tasks of positioning the height and orientation of the umbrella shaft may be used. Each should be seen as keeping within the spirit and scope of the present invention.  
         [0073]    This general configuration of supporting ribs, umbrella cover, and umbrella shaft are well known in the prior art. The present invention utilizes a configuration which is used within the industry by a number of manufacturers. There are, of course, other variations available concerning the manner and means of interconnecting the ribs, locking the lower ring, and securing the umbrella cover to the rib ends. The present invention, while somewhat unique in its use of a generally elliptical coverage area which is supported by a shaft which may be centered neither vertically nor horizontally, is not intended to claim the rib and shaft structure of the umbrella. It is, instead, intended to claim the means and method of providing an umbrella structure with a wheelchair which is adapted with an accessory mounting means. Therefore, the rib assembly taught in the preferred embodiment of the present invention may be modified as long as the result is the ability to support a desired area of coverage from an off-center shaft. Such other rib assemblies should be seen as keeping within the spirit and scope of the present invention.  
         [0074]    It should also be considered that there may be times when a wheelchair patron may be caught in more severe weather. This could include a substantial wind in addition to rain or other hazards. In such cases it would be helpful to be able to secure the umbrella. The very feature of the umbrella which makes it a good cover also makes it a potential hazard in a strong wind. Accordingly, additional anchoring may be desirable.  
         [0075]    Depicted in FIGS. 3 and 4 is a strap (generally  130 ) which may be securely fastened to the umbrella shaft ( 20 ) and then to opposite sides of the wheelchair ( 131 , 132 ). In order to simplify the operation of the anchoring strap ( 130 ) the ends ( 133 , 134 ) may each be adapted with a pad ( 139 ) which comprises velcro (R) on one side ( 135 ) and a velcro (R) receiving surface on an opposite side ( 136 ).  
         [0076]    The strap ( 130 ) could also be adapted with a sliding hook ( 137 ) which could be used to grasp the umbrella shaft at any desired point ( 138 ), such as on the upper ring ( 33 ). Then, by first grasping the shaft ( 41 ) at the desired point ( 138 ), and wrapping the pads about the opposite wheelchair arms ( 141 ,  142 ) and using the velcro (R) pads ( 139 ) to secure them, the umbrella (generally  100 ) is given additional security. Of course, there are a variety of means of connecting such a strap to both an umbrella shaft or selected points of stability upon a wheelchair. Such are too numerous to be separately described herein other than to say that each such configuration should be seen as in keeping within the spirit and scope of the present invention.  
         [0077]    One helpful and optional feature would be a two piece ( 171 ,  172 ) umbrella cover ( 10 ). This would allow some “venting” between the space above and below the cover without compromising the protection from rain and moisture. This provides further stability to the apparatus as it lessens the effect of an uplifting draft to the umbrella. Each of the figures depicting side views of the umbrella cover depict such a cover assembly.  
         [0078]    Accordingly, the principles of the present invention may be used with a variety of umbrella shaft, rib, and cover combinations. It would only be required that each would provide the requisite are of coverage and spatial relationship between the shaft and the area of coverage with respect to both the area covered and the elevation of the coverage area over the are of coverage. Accordingly, each such variations should be seen as keeping within the spirit and scope of the present inventions.  
         [0079]    Further modifications and variations other than those specifically described or referenced may be made to the disclosed embodiments without departing from the subject and spirit of the invention as further defined in the following claims. All such modifications and variations, as may be fairly included within the scope of these claims, are meant to be and should be considered part of the invention as described.