Wheelchair Attachment

Abstract

Wheelchair attachments, ordinarily installed in pairs, for enabling patients confined to wheelchairs to easily negotiate obstacles, such as curbs, in a conventional wheelchair having two small front wheels and two large rear wheels which the patient manually rotates to propel and maneuver the wheelchair. Each attachment includes an elevating member attachable to an axle of one of large rear wheels and having one or more prongs extending for a distance greater than the distance from the point at which the elevating member is attached to the wheelchair to the ground so that to mount a curb or similar obstacle the wheelchair can be made to stand on the elevating member with the large wheels elevated above the ground and against the curb or obstacle. The large wheels can then be manually rotated while against the curb to cause the wheelchair to climb the curb. The attachments of the invention must be used with a second attachment which includes an extendible wheel, or dolly, which is connectable to the wheelchair through supporting members and which can be manually extended backwards by the patient to a locked position. When both dollies of a pair of attachments are in this extended and locked position, the wheelchair can be tilted backwards manually to rest in a stable, tilted position on the two large wheels and the extended dollies or wheels with the two small front wheels, or casters, elevated. Curbs and other obstacles can then be simply negotiated in this tilted position by manually rotating the two large wheels so as to cause the wheelchair to stand on the pair of elevating members and then to climb the obstacle.

Description

BRIEF DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION

The invention relates to simple attachments to wheelchairs for enabling patients confined to wheelchairs to mount curbs and overcome other obstacles.

For the disabled individual, who has temporarily or permanently lost the use of his legs and must depend upon mechanical, usually manually operated, substitutes, such as wheelchairs, to move himself about, many of the minor obstacles and obstructions, which those fortunate individuals who can walk manage without difficulty and usually without notice, become extremely difficult to negotiate and, too often, insurmountable. Despite increased public awareness of the need to provide special facilities, such as ramps, which those individuals who are confined to wheelchairs can use, a short walk through any populated area quickly reveals many obstacles such as curbs, stairs, broken sidewalks and the like which, to an individual in a wheelchair, can make even a short trip a hazardous adventure. The present invention relates to simple attachments which can be quickly and easily affixed to conventional existing wheelchairs and which enable a wheelchair confined individual to easily overcome minor obstacles without great effort or skill.

Many attempts have been made in the prior art to produce either a wheelchair which can climb over or otherwise overcome obstacles or attachments to wheelchairs to enable such obstacles to be overcome. For example, the patents to Zamotin, U.S. Pat. No. 3,259,396, and Bennett et al. U.S. Pat. No. 2,701,005, show two types of wheelchairs of the prior art which purportedly can climb curbs and obstacles. However such devices have not found ready acceptance, perhaps because of their complexity or expense or some other problems. This invention relates to simple, inexpensive, reliable attachments which can be easily and quickly affixed to wheelchairs and which not only perform satisfactorily but which can be attached to conventional wheelchairs.

The wheelchair attachments of this invention are ordinarily used in pairs, each of the attachments being connected to one of the large wheels, which are conventionally manually rotated to propel the wheelchair, so that the wheelchair can be made to stand on the attachments with the large wheels clear of the ground and against a curb or similar obstacle so that these large wheels can then be employed to climb the curb. In the embodiment set forth below, each attachment includes an elevating member which has one or more extending prongs and which is attachable to the axle of a large wheel so that the member is manually rotatable about that axle but does no normally rotate with the wheel. The distance from the point of attachment of the member to the axle to a small spiked wheel which is mounted for free rotation about each extending prong is designedly greater than the distance from the point of attachment to the ground so that when the member is manually rotated until one of the spiked wheels is against the ground and then the large wheels are further rotated, the wheelchair is caused to rise stiltlike upon the two elevating members with the two large wheels off the ground. If, in this elevated position, the large wheels are leaning against a curb or similar obstacle, the large wheels can be simply rotated to cause the wheelchair to climb the curb or obstacle. If a pronged member having two or more prongs is employed, the wheelchair progressively is lifted from a first elevated position to a second position etc. in which the large wheels are successively further from the ground.

Each pair of elevating attachment is preferably employed with a second pair of different attachments each of which is comprised on an elongated member, a dolly or wheel, a supporting connection made up of two rods, and means for connecting the elongated member and one of the rods to the wheelchair. The elongated member of each of a pair of these attachments is preferably attached to the wheelchair, in the embodiment set forth below, and particularly to each of the conventionally provided handgrips at the top of the wheelchair back. The length of this elongated member is chosen to be less than the distance from the handgrip to the ground. Attached to the other end of each elongated member is the small wheel or dolly, which has been called a drop-back dolly, and which is similar to the small permanently attached front wheel of the wheelchair itself. Also attached to a point between the ends of this elongated member is one of the rods of the supporting connection, which as mentioned above, is made up of the two rods serially connected together, and forming a pivot at their point of connection. The other of the rods of this supporting connection is then attached to the wheelchair and preferably to the main rod which runs beneath and supports the wheelchair seat and back and which is attached to the axle of each large wheel. In a storage position, each dolly or wheel is positioned roughly below handgrip to which it is connected. This second pair of attachments is detailed in a patent application entitled WHEELCHAIR ATTACHMENT Ser. No. 778,458, filed Nov. 25, 1968.

To employ both pairs of attachments to mount an obstacle such as a curb, the dollies of each of the second pair of attachments are extended backwards by manually pushing downward on the pivot point between the two rods making up the supporting connection until the two rods lock by means of a scissor mechanism or the like. Next, both of the elevating members are rotated until one of the spiked wheels, of each member, is in contact with the ground and in front of a large wheel. After the dollies or extendible wheels are so extended to the operative position, the wheelchair can be easily tilted backwards so that the front two wheels are elevated, and the wheelchair rests at an angle of about 45.degree. in a stable position on the two large wheels and the two extended dollies.

The curb can now be mounted by moving the large wheels in the usual manner until the large wheels rise on the elevating members and the large wheels are directly applied against the curb substantially above the base of the curb. The wheelchair now rests on the two dollies, the two large wheels and the two elevating members. The large wheels can now be manually rotated to climb the curb with the two backwardly extending dollies or wheels remaining on the lower surface, and the elevating member being rotated by the curb to a position behind each large wheel. After the two large wheels are atop the curb or obstacle, the wheelchair can now be tilted forward again by shifting the body weight so that the wheelchair returns to its normal upright position resting atop the curb on the two large wheels and the two small front wheels. Each of the extended dollies or wheels, which are once again elevated, can now be manually rotated back to their storage position by manually releasing each of the locking arrangements and pulling upward on each of the pivot points at which the two rods making up each supporting connection are linked. The elevating members can then also be returned to their storage positions by manual rotation about the axles of the large wheels.

Many other objects and purposes of this invention will be clear after reading the following detailed description of the drawings.

A BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional wheelchair with the elevating attachments of this invention and the additional pair of dollies shown in the storage position.

FIG. 2 shows a view of the attachment which enables the wheelchair to be tilted backwards to a stable position.

FIG. 3 shows a front view of the elevating attachment.

FIG. 4 shows a side view of the elevating attachment.

FIG. 5 shows a view of a wheelchair with both pairs of attachments in the operative position about to climb a curb.

FIG. 6 shows a view of a wheelchair with both pairs of attachments in the midst of climbing a curb.

FIG. 7 shows a front view at another embodiment of the elevating attachment with a single prong.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to FIG. 1 which shows a conventional wheelchair 20 with a pair of the elevating attachments 21 of this invention added thereto, together with a pair of attachments 50, to enable a wheelchair confined patient to negotiate curbs, inclines, rough terrain, sand and rocks, and other obstacles with a minimum of difficulty or danger. The wheelchair 20 is conventional with a cloth back 22, a seat 24, armrests 26 and 27, a footrest 28, small front wheels 30 and 32, and manually operated large rear wheels 34 and 36. The operator of the wheelchair 20 is supported by a frame which includes a pair of vertically disposed posts 40 and 42, which have a cloth sheet or similar structure stretched between them to make up the back 22 and which extend downward and are permanently attached to the axles 41 and 43, respectively, of the large wheels 34 and 36, respectively, and also to horizontally supporting members 44 and 46, respectively. The posts 40 and 42 terminate in handgrips 51 and 53 which are provided so that the wheelchair 20 can be easily pushed by another as well as manually propelled by the operator. The horizontal members 44 and 46 in turn support front posts 47 and 48 which connect to the armrests 26 and 27, and which also support the struts which form the seat 24, In short, the wheelchair 20 shown in FIG. 1, is a simple conventional wheelchair which is locomoted by the patient manually rotating the large wheels 34 and 36 so that the wheelchair and patient are propelled in the direction which the patient chooses. In addition, the wheelchair 20 shown in FIG. 1 preferably is collapsible for storage and capable of being made ready for use from storage in a few seconds.

As mentioned above, the pair of elevating attachments 21, which function in a stiltlike fashion to enable each of the large wheels 34 and 36 to be lifted off the ground and applied to a curb or other obstacle at a point considerably above the base of the curb, are respectively. In FIG. 1, both of the elevating attachments 21 are shown in the storage position in which they in no way interfere with the normal operation of the wheelchair 20 nor rotate with the wheels 34 and 36. At the same time both of the attachments 21 much be capable of being manually rotated to an operative position where the spiked wheels 82 of the shorter prongs 84 of the attachment 21 contact the ground, as shown in FIG. 5.

Any suitable means of connection between the wheelchair 20 and the attachments 21 can be used. However, as shown in FIGS. 1, 3 and 4, the attachment 21 of this embodiment is provided with two apertures 86 and 88 connected by a slot 90 and the attachment 21 is connected to the axle 41 by removing the nonrotating bolt (not shown) which conventionally holds the axle 41 in place, and running the bolt through the aperture 86 or 88 through which it best fits so that the attachment 21 is held firmly but not immovably in place by the hub 94. Thus, the attachment is automatically held in the storage position during normal movement of the wheelchair 20 while easily and manually rotatable to the operative position, shown in FIG. 5, for climbing curbs and other obstacles.

As can be seen in FIGS. 3 and 4, the attachment 21, which has been called a Curb Leveler, is made up of two extending prongs 84 and 94, both of which emanate from an upper portion 96 from which the apertures 86 and 88 and the slot 90 has been removed. For reasons which will become apparent below, the prong 84 is made deliberately shorter than the prong 94.

Connected to the end of the prong 84 is a small spiked wheel 82 and to the end of the prong 94 is another small spiked wheel 98. Each of the wheels 82 and 98 is mounted within holders 100 and 102 respectively, and the holders 100 and 102 are permanently and immovably connected to the prongs 84 and 94 respectively, for example, by welding. Preferably, the wheels 82 and 98 are permitted rotate freely.

As can be seen in FIG. 4, the attachment 21 is bent outward from its point of connection to the axle 41 at a point roughly designated as 104 in order to avoid contacting the rim or tire of the wheel 34. Further, a lateral member 108 roughly parallels the rim of the wheel 34 and provides additional support for the prongs 84 and 94. As shown in FIG. 4, the member 108 curves about and protects the rims of the wheels 34 and 36.

Each of the pair of attachments 21 is intended to be left in place when the wheelchair 20 is collapsed and stored and each can be quickly and simply removed or attached. Further, no particular material or dimensions for the attachment 21 is required but, of course, the attachments 21 must be sufficiently strong to temporarily support at least most of the weight of the wheelchair 20 as well as the weight supported by the wheelchair 20.

Moreover, FIG. 1 also shows the two attachments 50 which are detailed in the aforementioned application Ser. No. 778,458, filed Nov. 25, 1968, attached to the conventional wheelchair 20. Each of these attachments 50 is virtually identical and each can be left in position while the wheelchair 20 is collapsed for storage. Reference is now made to FIG. 2 which shows in detail one of the attachments 50. As can be seen in FIG. 2, the dolly or wheel 52, which is used to catch the wheelchair 20 when it is tilted backward, is supported directly by an elongated member 54 which allows it to rotate freely in a conventional manner. The member 54 is in turn pivotally attached to an upper member 58 which is preferably attached to the wheelchair handle 51 or 53, as shown in FIG. 1, by cutting or removing the end of the rubber or plastic grip which conventionally covers the wheelchair handles 51 and 53 and inserting the conventional expansion lug 59 of the upper member 58 into the hollow hand grip or handle 51 or 53. By tightening the nut 60 which fits within the expandable lug 58, the lug 58 and be expanded within the hollow handle 51 or 53, and the attachment 50 firmly fixed to handle 51 or 53.

A bracket 64 is shown attached to the member 54 in a position more than midway between the expansion lug 59 and the wheel or dolly 52. Pivotably attached to this bracket 64 is a supporting connection 65 by which the wheel or dolly can be extended, made up of two separate rods 70 and 72. As can be seen in FIG. 1, the point of pivotal connection between rods 70 and 72 is within easy reach of the person in the wheelchair, so that when the scissorlike mechanism 66 located at the connection between rods 70 and 72 is manually pushed downward to cause the rods 70 and 72 to assume roughly a horizontal position, as shown in FIG. 5, the member 54 and wheel 52 are pivoted about the point 80 at which they attach to the upper member 51 and the dolly or wheel 52 moves backward to the operative position. In this embodiment, the rods 70 and 72 as connected to the scissor mechanism 66 trace an arc from about 25.degree. to over 180.degree. and lock in place at about 185.degree.. When locked, the attachment 50 will not collapse to its original storage position until the operator manually pulls upward on the scissor mechanism 66. Thus, there is virtually no possibility that the attachment 50 will collapse when the wheelchair is tilted backwards at approximately 45.degree..

The rod 72, and thus the connection 65, is attached to a short bracket 74, as shown in FIG. 1, which is in turn connected to wheelchair 20, for example, by removing the axle nuts and bolts (not shown) that hold the wheel 34 and positioning the bracket 74 so that the hole 76 is aligned with the boltholes by which the wheel 34 is attached to its axle 41. The axle bolts and nuts can then be reapplied tightly so that the bracket 74 is firmly and securely attached to the axle 41 in the manner shown in FIG. 1.

Reference is now made to FIG. 5 which shows the wheelchair 20 in a position about to mount the curb 79 with the pair of wheelchair attachments 50 locked in the stable extended position and the wheelchair 20 thus supported by both the large wheels 32 and 34 and two dollies or wheels 52, and with the pair of elevating attachments 21 each in the operating position so that the spiked wheels 82 are in contact with the ground. As is apparent from FIGS. 1 and 5, each of the wheels 52, in both the storage and extended operative position is elevated a considerable distance above the ground when the wheelchair 20 rests upright on the two front wheels 30 and 32 and the two large rear wheels 34 and 36. Thus, when the wheelchair 20 is manually tilted backwards to rest on the two wheels 52 and the large wheels 34 and 36, the small front wheels 30 and 32 are likewise elevated and as shown in FIG. 5, the front wheels 30 and 32 can then be placed atop or above an obstacle such as the curb 79 shown in FIG. 5, by rolling the wheelchair 20 forward in the tilted position until the large wheels 34 and 36 are at a short distance from the base of the curb 79. The angle between the tilted wheelchair 20 and the ground can, of course, be simply controlled by changing the length of member 54 and rods 70 and 72 to change the distance from the extended wheels 52 to the wheelchair 20 and the normal upright distance from the extended wheels 52 to the ground. A tilting angle of about 45.degree. is shown in FIG. 5, and this angle has been found quite satisfactory. At this angle, most patients using the second pair of attachments only with practice have been able to climb a 4-inch curb, to dismount a 15-inch curb, to go over parking lot dividers, and to overcome most common obstacles in streets, highways and sidewalks. By using both the elevating attachments and the second pair of attachments, a 9-inch curb can be climbed, a 15-inch curb can be dismounted and an obstacle 9 to 10 inches high and 8 to 12 inches wide can be easily overcome.

The attachments 21 can be manually rotated to their operative position as shown in FIG. 5 from the storage position shown in FIG. 1, either before or after the wheelchair 21 is tilted to the stable tilted position. Such rotation of the attachment 21 can be accomplished merely by grasping the attachments 21 and pushing downward until the wheels 82 each touch the ground.

To assume the tilted position, the individual in the wheelchair first moves both of the wheels 52 to the extended position by pushing downward on each of the scissor mechanism 66 until each of the attachments 50 is firmly locked in place. Then the wheelchair 20 is tilted backwards by the operator until the wheelchair 20 rests on the rear wheels 34 and 36 and both of the wheels 52. This tilting can be accomplished in any manner, for example, by producing slight backward momentum, then quickly and smoothly jerking the large wheels 34 and 36 forward and at the same time throwing the body weight backwards. With practice, this maneuver can be accomplished without substantial effort and without strain to the dollies or wheels 52 or the front wheels 30 and 32.

To climb the curb from this tilted position with the attachments 21 in the operative position, the patient first grasps two large wheels 34 and 36 and rotates them to cause the wheelchair 20 to stand on the wheels 82 of the short prongs 84 of both attachments 21 with the wheels 34 and 36 off the ground. The forward momentum of the wheelchair 20 next causes the wheelchair to rise still further onto both of the wheels 98 of the longer prongs 94. If the patient has gauged his initial distance from the curb correctly, the large wheels 34 and 36 will now contact the curb 79 at a location above the base as shown in FIG. 7, preferably with the attachments 21 leaning slightly forward to throw considerable weight onto the wheels 34 and 36. The wheelchair operator now merely continues to rotate the large wheels 34 and 36 manually to cause the wheels 34 and 36 to climb the curb 79 and, at the same time, drag the wheels 52 slightly forward. When done with a smooth, continuous motion from a proper starting position, the climb can be accomplished easily and without strain on either the operator, the wheelchair 20, or the attachments 21 and 50.

When the wheels 34 and 36 are atop the curb 79, the wheelchair operator can now tilt the wheelchair 20 forward, for example by repeating in reverse the maneuver used to assume the backward tilted position, to cause the new elevated front wheels 30 and 32 to resume contact with the ground and the wheels 52 to again become elevated. The wheelchair 20 is now safely atop the curb 79 and in the normal upright position resting on wheels 30, 32, 34 and 36 with the wheels 52 elevated. The wheels 52 can now be returned to their storage position by manually pulling upward on each of the scissor mechanisms 66 to rotate each of the wheels 52 back to the position shown in FIG. 1. Similarly, the attachments 21 can be manually rotated back to the storage position shown in FIG. 1.

Of course, it is not necessary that the attachments 21 have any particular number of prongs. More than two can be employed if desirable and in FIG. 7 an attachment 21 with a single prong 112 and a spiked wheel 114 is shown. Climbing with a single prong is, of course, substantially the same as climbing with a double prong as described above, except that the height with can be reached is necessarily less.

Experienced and skilled wheelchair operators, of course, have heretofore been able to accomplish a similar climbing maneuver without assisting devices, such as the attachments 50, simply by balancing on the two large wheels 34 and 36 although, of course, risking the substantial danger of falling over backwards with resulting damage to wheelchair and operator. The attachments 21 can be used by such people to increase the height of the curb which can be climbed. However, since such balancing takes time and skill to perfect, as well as being dangerous, the attachments 21 are most advantageously employed with other attachments such as the attachments 50 which any individual can learn to use safely and effectively in a very short length of time. The ability to correctly position the the wheels 34 and 36 the right distance from the base of the curb 79 can be quickly learned and failure to so position or to make the climb do not result in a dangerous fall but only a safe descent after which another attempt can be made. Thus, the attachments 50 when used with the elevating attachments 21 enable the above-described climbing operation to be done with complete safety and ease. Even should one of the attachments 50 fail during climbing, tests have indicated that either of the attachments 50 along is sufficient to support the wheelchair 20. The only real source of danger is the possible human error of forgetting to extend either of the wheels 52 before the wheelchair 20 is tilted.

As mentioned, the attachments 21 and 50 can be used alone as well as in combination. For example, the attachments 21 can be used alone in a pole-vaulting fashion to jump over obstacles such as broken sidewalks, soft ground, etc. However, since many maneuvers required or are best performed with both pairs of attachments 50 and 21, the wheelchair 20 preferably is equipped with both especially since using both attachments 50 and 21 to climb a curb substantially increases the height of the curb which can be climbed over the height which can be climbed with either the attachments 50 or attachments 21 alone.

Of course, the patient cannot only mount curbs but can overcome virtually any type of minor obstacle with the attachments 50, either alone or in combination with the attachments 22. Use of the attachments 50 eases even movement over sand and rough terrain, which is ordinarily very difficult because of the tendency of the small front wheels 30 and 32 to plow and pitch the operator forward. By assuming the tilted position while moving over sand and rough ground, the large rear wheels 34 and 26 are converted into the lead wheels and progress is thus substantially easier. Even if the wheelchair 20 veers off its intended course due to the fact that one of the wheels 52 is deeper in sand or hits a rock or hole, the patient can simply continue by lifting the wheels 52 a few inches off the ground and at the same time manually turning his wheelchair 20 a few degrees with his large wheels 34 and 36 until he can resume his intended course. With this maneuver, which can be quickly and simply learned, a wheelchair confined patient can make even a 90.degree. turn or reverse his direction by 180.degree. with ease.

Although not especially designed for this purpose, it is believed that use of the attachments 50 will reduce the prevalence of pressure ulcers over the ischia in wheelchair-confined individuals. By resuming the tilted position for a few minutes each hour, it has been demonstrated that pressures on critical regions of wheelchair-confined individuals are reduced by about 35 percent so that even those patients who must spend 10 to 15 hours a day in their wheelchairs can avoid or at least reduce the chances of incurring this common difficulty. Further, the attachments 50 permit a conventional wheelchair to be converted into a comfortable lounge chair simply by resuming the tilted position.

Adding to their advantages is the ease with which both the attachments 50 and 21 can be removed from one wheelchair and transferred to another wheelchair. The attachments 50 can be removed from one wheelchair 20 and transferred to another in about 10 minutes, and removal and addition of the attachments 21 can also be rapidly accomplished. Of course, it may be desirable to permanently fix the attachments 50 to the wheelchair 20 or to construct a wheelchair with the attachments 50 as a permanent part thereof. Likewise, it may be desirable to build a wheelchair with the attachments 21 permanently affixed or to permanently attach the attachments 21 to an existing conventional wheelchair. However, until all wheelchairs are so equipped, the adaptability of the attachments 50 and 21 to any conventional wheelchair makes them especially useful.

Further, the inherent simplicity of both the attachment 50 and attachments 21 in comparison to the functions which they perform makes them both inexpensive and economical. Since no major alteration of the wheelchair to which they are attached is necessary to even desirable, the total cost of the attachments 50 and 21 to the wheelchair-confined individual is nominal especially compared to the mobile capability which they give him. Their simplicity also virtually guarantees trouble-free operation and precludes expensive maintenance. In short, the attachments 50 and 21 are both simple, inexpensive, reliable devices, easily and quickly attachable to conventional wheelchairs and capable of enabling a wheelchair-confined individual to overcome common obstacles and move freely about his environment.

As mentioned above, the attachments 21 can also be permanently connected to the wheelchair or can be removable as in the embodiment set forth above. Further, the attachments 21 and the attachments 50 while preferably used together can each be used separately. Many changes and modifications in the examples set forth above will be apparent to any one of ordinary skill in the art and the invention is intended to be limited only by the following claims.

Claims

We claim:

1. A wheelchair attachment for overcoming obstacles in a wheelchair with a pair of driving wheels, each having an axle, comprising means mountable on said wheelchair for enabling said wheels to be elevated above the ground including stilt means with a member attached to said axle of one of said wheels having a length greater than the distance from said axle to the ground and a spiked wheel connected to the end of said member which contacts the ground, said member being manually rotatable from a storage position to an operative position in contact with the ground and further rotatable in response to manual rotation of said wheels to cause said wheels to be elevated.

2. An attachment as in claim 1 wherein said stilt means includes a member and spiked wheel attached to each said axle.

3. An attachment as in claim 2 wherein said member terminates in a single end which contacts the ground.

4. An attachment as in claim 2 wherein said member terminates in two ends at different distances from the point of said member attached to said axle.

5. In combination, wheelchair attachments for a wheelchair with a pair of driving wheels comprising,

wheelchair-supporting means mountable behind said wheelchair so that said wheelchair can be tilted backwards to a stable tilted position in which at least a portion of the weight of said wheelchair and the weight supported by said wheelchair is supported by said supporting means, and

means mountable on said wheelchair for enabling said wheels to be elevated above the ground while said wheelchair is tilted backwards.

6. An attachment as in claim 5 wherein said attachments are for overcoming obstacles and wherein said supporting means includes means for holding said supporting means in position supporting said wheelchair during the time said wheelchair is operated to overcome said obstacle, and said enabling means includes stilt means manually rotatable from a storage to a operative position and further rotatable in response to manual rotation of said wheels to cause said wheels to be elevated.

7. An attachment as in claim 1 wherein said wheelchair includes a pair of small front wheels and said driving wheels include a pair of large rear wheels which are manually operated to move said wheelchair, wherein said supporting means includes at least a single wheel and wherein said wheelchair is operated to overcome said obstacle by manually rotating said large rear wheels.

8. An attachment as in claim 7 wherein said supporting means includes at least two of said single wheels, each independently attached to said wheelchair.

9. An attachment as in claim 8 including manually operable means for moving each of said single wheels from a storage position to an operative position in which said wheelchair can be tilted backwards to said stable position and for moving each of said single wheels to said storage from said operative position.

10. An attachment as in claim 9 including means to lock each of said single wheels in said operative position.

11. An attachment as in claim 10 wherein said supporting means includes a first member connected at one end to one of said single wheels to as to allow said one single wheel to rotate freely and at the other end pivotably connected to said wheelchair, said first member having a length less than the distance from the point said first member is attached to said wheelchair to the ground when said wheelchair is in the upright position, a second member pivotably connected one end to said first member between said ends, and a third member pivotably attached at one end to the other end of said second member and pivotably connected to said wheelchair at a point lower than the point of connection to said first member at the other end of said third member so that said first member can be pivoted about its point of connection to said wheelchair to extend said one single wheel backwards by manually pushing downward on the point of connection between said second and third members.

12. An attachment as in claim 11 wherein each of said wheels has an axle and said stilt means includes a member attachable to said axle of one of said wheels and having a length greater than the distance from said axle to the ground.

13. An attachment as in claim 12 including a spiked wheel connected to an end of said member which contacts the ground.

14. An attachment as in claim 13 wherein said stilt means includes a member and spiked wheel attached to each said axle.

15. An attachment as in claim 14 wherein said member terminates in a single end which contacts the ground.

16. An attachment as in claim 15 wherein said member terminates in two ends at different distances from the point of said member attached to said axle.

17. A wheelchair comprising:

a pair of small front wheels,

a pair of manually rotatable rear wheels,

frame means connected to said front and rear wheels and forming a seat,

wheelchair-supporting means mounted on said frame means including first and second supporting wheels, means attaching said supporting wheels to said frame means and means for moving said supporting wheels from a storage position with said supporting wheels above the ground and adjacent said rear wheels a tilted position rearwardly spaced from said rear wheels and in which at least a portion of the weight of said wheelchair and the weight supported by said wheelchair is supported by said supporting means, and

means mounted on said wheelchair for enabling said rear wheels to be elevated above the ground.

18. A wheelchair as in claim 17 wherein said supporting means includes a pair of extendible wheels.

19. A wheelchair as in claim 18 wherein said supporting means is movable from a storage to an operative position and from said operative to said storage position and, wherein said enabling means is movable to a storage to an operative position and from an operative to a storage position.

20. A method of operating a wheelchair driven by a pair of wheels to overcome obstacles comprising the steps of

tilting the wheelchair backwards until the wheelchair is in a stable tilted position in which the weight of the wheelchair and the weight supported by the wheelchair is at least partially supported by supporting means mounted behind said wheelchair

elevating the driving wheels above the ground and then against the obstacle to be overcome, and

manipulating said wheelchair in said stable tilted elevated position to climb said obstacle.

21. A method as in claim 20 including the step of manually shifting said supporting means from a storage to an operative position.

22. A method as in claim 21 including the step of manually shifting said supporting means from said operative to said storage position after said obstacle has been overcome.

23. A method of overcoming obstacles in a wheelchair having a pair of small front wheels, a pair of large manually rotatable rear wheels, a pair of extendible wheels manually movable from a storage position to a stable, operative position in which said extendible wheels are behind said rear wheels and are elevated above the ground when said wheelchair rests on said front and rear wheels and stilt means mounted on the axle of said large wheels and having a member whose length is greater than the distance from said axle to the ground so that said large wheels can be elevated above the ground by rotating the large wheels when the stilt means is placed in contact of the ground in front of the large wheel comprising the steps of:

manually moving said extendible wheels from said storage to said operative position,

manually moving said stilt means from said storage to said operative position,

manually tilting said wheelchair backwards, to a stable tilted position in which said wheelchair rests on said extendible wheels and said rear wheels,

manually rotating said rear wheels to cause said large wheels to be elevated and to contact said obstacle above said ground,

manually continuing the rotation of said rear wheel to cause said wheelchair to overcome said obstacle,

manually returning said extendible wheels to said storage position after said obstacle has been overcome, and

manually returning said stilt means to said storage position after said obstacle has been overcome.

24. A method of overcoming obstacles in a wheelchair having two driving wheels and an elevating member attached to each of said wheels, rotatable about the center of said wheels and having a length greater than the point of attachment of said member to said wheel to the ground so that said wheelchair can be made to rise, with said wheels elevated, onto said members comprising the steps of:

manually rotating both of said members so that said members contact the ground,

rotating said wheels so that said wheels are elevated above the ground and then moved into contact with said obstacle, and

continuing rotating said wheels so that said wheelchair climbs said obstacle.

25. A wheelchair attachment for overcoming obstacles in a wheelchair with a pair of driving wheels, each having an axle, comprising means mountable on said wheelchair for enabling said wheels to be elevated above the ground including stilt means with a member attached to said axle of one of said wheels having a length greater than the distance from said axle to the ground and a wheel connected to the end of said member which contacts the ground, said member being manually rotatable from a storage position to an operative position in contact with the ground and further rotatable in response to manual rotation of said wheels to cause said wheels to be elevated.

26. An attachment for a wheelchair with a pair of driving wheels attached to an axle comprising means mountable on said wheelchair for enabling said wheels to be elevated above the ground for overcoming obstacles, said enabling means including stilt means with a member attached to said axle and terminating at two ends at different distances from the point of attachment of said member to said axle, said member being manually rotatable from a storage position to an operative position with one of said ends in contact with the ground and further rotatable in response to manual rotation of said wheels to cause said wheels to be elevated with the other of said ends in contact with the ground.