Unilateral transition means for adapting a wheelchair

Abstract

A transition means for adapting a wheelchair is disclosed wherein a user or an occupant of the wheelchair is enabled to repeatably alternate the wheelchair between an original mode and an adapted mode by engaging and disengaging a unilaterally-connected adaptive implement.

Claims

1. A load transitioning apparatus capable of alternating a wheelchair between a first load-bearing configuration and a second load-bearing configuration, the wheelchair comprising a pair of rear drive wheels, a pair of forward caster wheels, and a frame, the load transitioning apparatus being operatively interposed between the frame of the wheelchair and a ground-contacting adaptive implement, the load transitioning apparatus comprising: a) an arcuate bearing surface; b) a moveable bearing capable of releasably engaging in load-bearing contact with the arcuate bearing surface; c) a first spring capable of urging of the moveable bearing out of load-bearing engagement with the arcuate bearing surface; d) a biasing mechanism capable of switching between a first state and a second state, the first state corresponding to a relaxed form of the first spring to prepare the load transitioning apparatus to transition from the first load-bearing configuration to the second load-bearing configuration, the relaxed form of the first spring permitting movement of the moveable bearing toward engagement with the arcuate bearing surface, the second state corresponding to a deflected form of the first spring to prepare the load transitioning apparatus to transition from the second load-bearing configuration to the first load-bearing configuration, the deflected form of the first spring urging the moveable bearing away from engagement with the arcuate bearing surface; wherein, while the wheelchair is in the first load-bearing configuration the moveable bearing is maintained out of engagement with the arcuate bearing surface, with the pair of rear drive wheels and the pair of forward caster wheels of the wheelchair fully bearing a forward portion of a load supported by the wheelchair and, while the wheelchair is in the second load-bearing configuration the moveable bearing is maintained in load-bearing engagement with the arcuate bearing surface with the load transitioning apparatus transmitting the forward portion of the load supported by the wheelchair to the ground-contacting adaptive implement.

2. The load transitioning apparatus of claim 1, further comprising a second spring capable of urging the moveable bearing toward contact with the arcuate bearing surface.

3. The load transitioning apparatus of claim 1 defining a singular joint and being capable of asymmetric unilateral attachment to a forward lateral portion of the frame of the wheelchair.

4. The load transitioning apparatus of claim 1, the biasing mechanism comprising an output rod capable of assuming a retracted disposition and a protracted disposition wherein, while the biasing mechanism is in the first state, the output rod assumes the retracted disposition to cause the first spring to assume the relaxed form and, while the biasing mechanism is in the second state, the output rod assumes the protracted disposition to cause the first spring to assume the deflected form.

5. The load transitioning apparatus of claim 1 being capable of alternating the moveable bearing between a position of load-bearing engagement with the arcuate bearing surface and a position of disengagement from the arcuate bearing surface, wherein switching the biasing mechanism causes the load transitioning apparatus to become responsive to reclining of the wheelchair by a user to enable the user to alternate the position of the moveable bearing.

6. The load transitioning apparatus of claim 1, wherein reclining the wheelchair enables movement of the moveable bearing along an arcuate path.

7. The load transitioning apparatus of claim 1, the arcuate bearing surface further comprising a nested groove having a profile congruent with the profile of the moveable bearing, the moveable bearing adapted for releasable engagement within the nested groove.

8. The load transitioning apparatus of claim 7, wherein, while the front caster wheels of the wheelchair are bearing the forward portion of the load supported by the wheelchair, the load transitioning apparatus is capable of being prepared by the user for movement of the moveable bearing into the nested groove to enable the user to effectuate movement of the moveable bearing into the nested groove, wherein switching of the biasing mechanism to the first state causes the load transitioning apparatus to become responsive to reclining of the wheelchair, with the moveable bearing remaining out of the nested groove and the front caster wheels of the wheelchair continuing to bear the forward portion of the load supported by the wheelchair, and wherein reclining of the wheelchair effectuates movement of the moveable bearing into the nested groove.

9. The load transitioning apparatus of claim 8, wherein, while the load transitioning apparatus is transmitting the forward portion of the load supported by the wheelchair to the ground-contacting adaptive implement, the load transitioning apparatus is capable of being prepared by the user for movement of the moveable bearing out of the nested groove to enable the user to effectuate movement of the moveable bearing out of the nested groove, wherein switching of the biasing mechanism to the second state causes the load transitioning apparatus to become responsive to reclining of the wheelchair, with the moveable bearing remaining in the nested groove and the ground-contacting adaptive implement continuing to bear the forward portion of the load supported by the wheelchair, and wherein reclining of the wheelchair effectuates movement of the moveable bearing out of the nested groove.

10. The load transitioning apparatus of claim 1, further configured to restrict downward rotation of a rotatable portion of the load transitioning apparatus, wherein, during transitioning of the wheelchair to the second load-bearing configuration, the rotatable portion assumes a predetermined angular disposition relative to the frame of the wheelchair.

11. The load transitioning apparatus of claim 1, the ground-contacting adaptive implement comprising a pivotable caster wheel assembly.

12. The load transitioning apparatus of claim 1, ground-contacting adaptive implement comprising a ski assembly.

13. A load transitioning apparatus capable of alternating a wheelchair between a first load-bearing configuration having a pair of forward caster wheels disposed on the wheelchair supporting a forward portion of a load carried by the wheelchair, and a second load-bearing configuration having a ground-contacting adaptive implement supporting the forward portion of the load carried by the wheelchair, the load transitioning apparatus comprising: I. a fixed member and a rotatable member, the fixed member capable of securing to a lateral frame portion of the wheelchair, the rotatable member secured to the ground-contacting adaptive implement, the rotatable member rotatably connected to the fixed member, the rotatable member capable of rotating relative to the fixed member about an axis passing through the load transitioning apparatus; II. an arcuate bearing surface and a moveable bearing, the moveable bearing capable of journaling along an arcuate path coaxial to the arcuate bearing surface about the axis upon rotation of the rotatable member relative to the fixed member, III. a bistable switching mechanism capable of togging between a first, engaging state and a second, disengaging state to switchably bias a net urging force sustained against the moveable bearing in an engaging direction to enable load-bearing engagement with the arcuate bearing surface, and to switchably bias the net urging force sustained against the moveable bearing in a disengaging direction to enable load-bearing disengagement from the arcuate bearing surface; wherein, while the wheelchair is in the first load-bearing configuration with the bistable switching mechanism in the first, engaging state, reclining of the wheelchair imparts movement of the moveable bearing along the arcuate path and permits movement of the moveable bearing into a predetermined position of load-bearing engagement with the arcuate bearing surface to relieve the pair of forward caster wheels from the forward portion of the load carried by the wheelchair, and while the wheelchair is in the second load-bearing configuration with the bistable switching mechanism in the first, engaging state, the moveable bearing remains in the predetermined position of load-bearing engagement with the arcuate bearing surface, and the load transitioning apparatus transmits the forward portion of the load carried by the wheelchair to the ground-contacting adaptive implement, with the ground-contacting adaptive implement being maintained in a predetermined deployed position, and while the wheelchair is in the second load-bearing configuration with the bistable switching mechanism in the second, disengaging state, reclining of the wheelchair effectuates movement of the moveable bearing out of the predetermined position of load-bearing engagement with the arcuate bearing surface and imparts movement of the moveable bearing along the arcuate path to relieve the ground-contacting adaptive implement from supporting the forward portion of the load carried by the wheelchair and to transmit the forward portion of the load to the forward caster wheels, and while the wheelchair is in the first load-bearing configuration with the bistable switching mechanism in the second, disengaging state, the rotatable member of the load transitioning apparatus is capable of being freely rotated relative to the fixed member of the load transitioning apparatus.

14. The load transitioning apparatus of claim 13, the bistable switching mechanism being capable of applying pressure against a disengagement spring, the disengagement spring capable of assuming a relaxed form having the net urging force sustained against the moveable bearing biased in the engaging direction, wherein, while the wheelchair is in the second load-bearing configuration with the disengagement spring assuming the relaxed form, the load transitioning apparatus maintains the wheelchair in the second load-bearing configuration.

15. The load transitioning apparatus of claim 14, the disengagement spring further capable of assuming a deflected form having the net urging force sustained against the moveable bearing biased in the disengaging direction, wherein, while the wheelchair is in the second load-bearing configuration, toggling the bistable switching mechanism to bias the net urging force sustained against the moveable bearing in the disengaging direction causes the disengagement spring to assume the deflected form to prepare the moveable bearing for disengagement from the arcuate bearing surface and to arm the load transitioning apparatus for transitioning of the wheelchair to the first load-bearing configuration, the load transitioning apparatus becoming responsive to reclining of the wheelchair by the user to enable release of the moveable bearing from a position of load-bearing engagement with the arcuate bearing surface and to impart journaling of the moveable bearing along the arcuate path.

16. The load transitioning apparatus of claim 15, further comprising an engagement spring for applying a sustained urging force against the moveable bearing in the engaging direction, wherein, while the bistable switching mechanism is in the first, engaging state, the sustained urging force applied by the engagement spring is greater than the sustained urging force applied by the disengagement spring, imparting a tendency for the moveable bearing to move into the position of load-bearing engagement with the arcuate bearing surface, and wherein, while the bistable switching mechanism is in the second, disengaging state, the sustained urging force applied by the engagement spring is less than the sustained urging force applied by the disengagement spring, imparting a tendency for the moveable bearing to move out of the position of load-bearing engagement with the arcuate bearing surface.

17. The load transitioning apparatus of claim 16 wherein, while the wheelchair is in the first load-bearing configuration, the moveable bearing is maintained in the position of disengagement from the arcuate bearing surface, with said pair of rear drive wheels and said pair of forward caster wheels fully bearing the load supported by the wheelchair, the load transitioning apparatus remaining unresponsive to reclining of the wheelchair until the user toggles the bistable switching mechanism to the first, engaging state and the user subsequently reclines the wheelchair, and wherein, while the wheelchair is in the second load-bearing configuration, the moveable bearing is maintained in the position of engagement with the arcuate bearing surface, with the ground-contacting adaptive implement bearing the portion of the load supported by the wheelchair, the load transitioning apparatus remaining unresponsive to reclining of the wheelchair until the user toggles the bistable switching mechanism to the second, disengaging state and the user subsequently reclines the wheelchair.

18. The load transitioning apparatus of claim 13, the bistable switching mechanism comprising an input knob wherein, upon manipulation thereof by a user, subsequent momentary reclining of the wheelchair by the user imparts rotation of the rotatable member of the load transitioning apparatus to dispose the moveable bearing in the predetermined position of engagement with the arcuate bearing surface and to dispose the ground-contacting assembly in the predetermined deployed position, the input knob configured for receiving a manual force applied by the user and for transferring said manual force to enable toggling of the bistable switching mechanism between a first, engaging switch state and a second, disengaging switch state.

19. The load transitioning apparatus of claim 13, the ground-contacting adaptive implement comprising a pivotable caster wheel assembly or a ski assembly.

20. The load transitioning apparatus of claim 13 being capable of asymmetric unilateral attachment to a forward lateral portion of the frame of the wheelchair.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:

(2) FIG. 1A shows a wheelchair occupant holding an adapting member equipped with a large caster wheel implement while seated in a wheelchair outfitted with a mounting member.

(3) FIG. 1B shows the wheelchair occupant leaning forward and connecting the adapting member to the mounting member.

(4) FIG. 1C shows the wheelchair occupant manipulating a sliding knob on the adapting member to put the adapter into a pre-operative internal stage.

(5) FIG. 1D shows the wheelchair occupant sitting upright and beginning to perform a wheel-stand maneuver to effectuate the transition of the adapter to the operative state.

(6) FIG. 1E shows the wheelchair occupant sitting upright with the wheelchair in the operative state after having performed the wheel-stand maneuver.

(7) FIG. 2 is a perspective view of an unoccupied wheelchair outfitted with a separable-type adapter having a mounting member and an adapting member, the adapting member equipped with a caster wheel implement.

(8) FIG. 3A displays the coupling relationship of the mounting member with the adapting member, both detached from the wheelchair.

(9) FIG. 3B displays an alternate view of the coupling relationship of the mounting member with the adapting member, both detached from the wheelchair.

(10) FIG. 3C displays the mounting member of the separable-type adapter.

(11) FIG. 4A is a sectional view illustrating the positioning of the internal components of the load-transfer assembly and the positioning of the adapting member relative to the mounting member during the internal inoperative stage.

(12) FIG. 4B is a sectional view illustrating the positioning of the internal components of the load-transfer assembly and the positioning of the adapting member relative to the mounting member during the internal pre-operative stage.

(13) FIG. 4C is a sectional view illustrating the positioning of the internal components of the load-transfer assembly and the positioning of the adapting member relative to the mounting member during the internal operative stage.

(14) FIG. 4D is a sectional view illustrating the positioning of the internal components of the load-transfer assembly and the positioning of the adapting member relative to the mounting member during the internal pre-inoperative stage.

(15) FIG. 5 is a perspective view of a wheelchair outfitted with two inseparable-type adapters, both equipped with ski implements, in the operative position.

(16) FIG. 6 is a perspective view of a wheelchair outfitted on a first side with a separable-type adapter equipped with a caster wheel implement, and the wheelchair outfitted on a second side with a clamping inseparable-type adapter equipped with a shovel implement.

(17) FIG. 7A displays a clamping inseparable-type adapter comprising a detent element and a detent bar which limit the range of motion of a moveable portion of the adapter.

(18) FIG. 7B displays an alternate view of the clamping inseparable-type adapter.

DETAILED DESCRIPTION OF THE DRAWINGS

(19) An apparatus for unilateral attachment of an adaptive implement to a wheelchair 100 and for transitioning the same between a load-sharing state and a non-load-sharing state is disclosed.

(20) FIG. 1A depicts a wheelchair occupant seated in his wheelchair 100 and holding an adapting member 120 equipped with a large caster wheel 122 having a diameter of 8 inches. The wheelchair comprises opposing drive wheels, 101A and 101B, footrest 103, primary caster assemblies 108A (visible) and 108B (not shown) comprising caster wheels 106A (visible) and 106B (not shown), respectively. Attached to forward lateral frame element 102A of wheelchair 100 is a mounting member 110. Opposing forward lateral frame element 102B does not have an attached mounting member, although it would suitably accommodate a mounting member of mirror-image construction in comparison to that of mounting member 110. The mounting member 110 is attached to forward lateral frame element 102A such that it occupies a space immediately above caster cylinder 104 which houses bearings and fastening elements to enable primary caster assembly 108A to pivot freely in all directions while also remaining securely affixed to the wheelchair in a load-sharing fashion. The footrest 103, in this illustration, is in its lowest possible position relative to the ground surface 150 and the caster wheels 106A (visible) and 106B (not shown) are in direct contact with the ground surface 150.

(21) FIG. 1B depicts the seated wheelchair occupant leaning forward and placing the adapting member 120 in a coupled position relative to the mounting member 110. With his left hand, the user is also pulling inwardly on expansion pin assembly lever handle 124 to secure the inserted position of an expanding insertion pin (not shown) relative to the mounting member 110; the coupling or union established therein prevents relative lateral movement between the adapting member 120 and the mounting member 110, yet permits relative rotational movement therebetween. Input knob 126 is seen in its forwardmost position.

(22) In FIG. 1C, the user is pushing with his right hand, in the rearward direction, against the input knob 126 to switch the adapting member to an internal pre-operative stage, after which action the input knob 126 will return to its forwardmost position.

(23) FIG. 1D shows the user sitting upright, preparing to perform a wheel-stand maneuver. At this moment, the large caster wheel 122, primary caster wheels 106A (visible) and 106B (not shown), and rear drive wheels 101A and 101B are all in contact with the ground surface 150. Also, at this time, the primary caster wheels 106A and 106B are bearing a portion of the load carried by the wheelchair, which includes both the weight of the occupant and the wheelchair itself. The adapting member 120 and the large caster wheel 122 are non-load-bearing and are upwardly and downwardly rotatable about the axis of the expanding insertion pin (not shown).

(24) Illustrated in FIG. 1E, as the user controllably leans his torso backwards while pushing forwardly against the upper regions of rear drive wheels 101A and 101B, the large caster wheel 122 remains in contact with the ground surface 150 and the primary caster wheels 106A and 106B become elevated from the ground surface 150 so that they no longer bear any portion of the load that is carried by the wheelchair. The primary caster wheels 106A (visible) and 106B (not shown) as well as the footrest 103 are all transitioned to an increased vertical position relative to the ground surface 150, thereafter leaving substantially more clearance beneath these forward structures of the wheelchair 100. As a result of this increased clearance, obstacles laying on or contained within the ground surface 150 may be more readily traversed over by the user, who also experiences decreased rolling resistance and increased forward stability with now having the separable-type adapter 180 in its operative state.

(25) Removing the adapting member 120 and caster wheel 122 from the wheelchair 100 is accomplished by carrying out the sequence depicted in FIGS. 1A through 1E in reverse order, which ultimately results in transitioning the separable-type adapter 180 from the operative state to the inoperative state and subsequently decoupling the adapting member 120 from the mounting member 110.

(26) FIG. 2 displays a similarly-configured wheelchair 100 left unoccupied and with an attached adapting member 120 equipped with a large caster wheel 122. The separable-type adapter 180, in this depiction, is in its operative state. A curved tubular support member 230 interconnects the pivotable caster assembly 240 to the adapting member 120. The curved tubular support member 230, which disposes the pivotable caster assembly 240 at a central forward location relative to the wheelchair 100, may also serve as a caster positioning means. By loosening tube clamp 232 and caster mounting block 226 in relation to the curved tubular support member 230, rotation of the curved tubular support member 230 may be performed in either direction and may be used to alter both the pitch orientation and the roll orientation of the pivot axis of the pivotable caster assembly 240. This method, used in conjunction with rotational adjustment of the mounting member 110 about the lateral frame element 102A of the wheelchair 100 and vertical adjustment of the caster cylinder 224 relative to the caster mounting block 226, permits a high degree of adjustability of the adaptive implement (the pivotable caster assembly 240) relative to the wheelchair 100. It is to be understood that many other details for attachment, adjustment, release, and other operations of the adapter may be made without departing from the scope of the invention as claimed, and that additional attachment assemblies may be present, as desired, also without departing from the scope of the invention as claimed.

(27) FIG. 3A displays a partially-exploded view of the adapting member 120 and the mounting member 110, indicating the manner and direction in which the expanding insertion pin 340 inserts into tubular receptacle 382 of the mounting member 110. Other elements of the adapting member 120 and the mounting member 110, which were implied though not described in previous figures, are visible in FIGS. 3A, 3B and 3C. The mounting member 110 comprises an upper fastening body 360, an upper arcuate fastening element 362, a lower fastening body 366, a lower arcuate fastening element 368, fastening bolts 364A, 364B, 364C, and 364D, a rigid structural plate 370, structural plate bolts 372A 372B and 372C, and a bearing plate 374. A tubular receptacle 382 projects through an aperture in bearing plate 374 and also through an aperture in rigid structural plate 370, and is fastened on both sides by receptacle nuts 380A and 380B.

(28) The adapting member 120 comprises a load-transfer assembly 310, a solid body 312, and connector bolts 316A and 316B to connect the load-transfer assembly 310 to the solid body 312. To aid in rigidizing and ensuring the integrity of the bolted connection between the load-transfer assembly 310 and the solid body 312, a pair of saddle washers 314 are placed therebetween. Projecting through an aperture in the solid body 312 is an expanding insertion pin 340 operatively connected to a cam assembly 320, which is actuated by user manipulation of the lever handle 124. Upon inserting the expanding insertion pin 340 into the tubular receptacle 382 of the mounting member 110 and subsequently pulling back on the lever handle, the expanding insertion pin 340 establishes and maintains a secure grip within the tubular receptacle 382 to effectively secure the adapting member 120 to the mounting member 110. By virtue of the strong union created between the adapting member 120 and the mounting member 110, the adapted wheelchair is capable of withstanding the torsional strain and asymmetric loading placed thereupon during normal use, and rotation of the adapting member 120 about the axis of the expanding insertion pin 340 is sufficiently isolated to ensure that the separable-type adapter 180 may be transitioned without being hindered by any torsional strain and asymmetric loading placed upon the separable-type adapter 180 as a result of a load borne completely or in part by the separable-type adapter 180.

(29) Adjustments made at the union between the expanding insertion pin 340 and the cam assembly 320, such as by turning the lever handle 124 around a threaded end (not shown) of the expanding insertion pin 340, amplifies the pressure established between the expanding insertion pin 340 and the inner surface of the tubular receptacle 382 to further unify the adapting member 120 with the mounting member 110. As a result, during transition and while in the operative state, most if not all “wiggle,” vibration and “play” between the adapting member 120 and the mounting member 110 is eliminated during normal use of the adapted wheelchair. While traversing over ground surfaces, the occupant of the wheelchair 100 experiences a very solid and secure ride due to the tightly unified separable-type adapter 180 and wheelchair 100.

(30) The adapting member 110 additionally comprises a moveable bearing assembly 348 which comprises a cylindrical bearing element 350 connected to an arcuate bearing element 352. Upon the user manipulating the input knob 126 by pushing it in the rearward direction, the cylindrical bearing element 350 and the arcuate bearing element 352 move, linearly, in the forward direction or in the rearward direction, depending on the current internal stage of the load-transfer assembly 310. The forwardmost and rearwardmost positions occupied by the arcuate bearing element 352 are limited by the length of the bearing opening 330 of bearing sleeve 356 which surrounds the load-transfer assembly 310 and which is bolted or welded to the solid body 312 to prevent linear movement or rotation of the bearing sleeve 356. Repeated manipulation of the input knob 126 alternates the position of the moveable bearing assembly 348 between a forward position and a rearward position within the bearing opening 330.

(31) Projecting through the bearing plate 374 and into the rigid structural plate 370 is an adjustment bolt 390. Upon removal of the adjustment bolt 390, the bearing plate 374 may be rotated about the axis 384 of the tubular receptacle 382 relative to the rigid structural plate 370, after which the adjustment bolt 390 may be reinserted and tightened into one of the three other adjustment holes 390 to alter the effective angle created between an attached adaptive implement (in this case, the caster wheel) and the wheelchair 100 upon deploying the separable-type adapter 180 into the operative state.

(32) It is important to note that the aforementioned arrangement of the moveable bearing assembly 348, the bearing sleeve 356, the load transfer assembly 310, the solid body 312, the expanding insertion pin 340, the mounting member 110, and all fastening and clamping means associated therewith, allows for sufficient movement of the cylindrical bearing element 350 so that it may readily engage with and disengage from the nested groove 378, and wherein the adapting member 120 of the separable-type adapter 180 is releasably securable to the mounting member 110 such that the separable-type adapter 180 maintains a position and orientation relative to the wheelchair while in the load-sharing state, preferably through many cycles of attaching, operating, and releasing the adapting member 120 relative to the mounting member 110. In the process, all torsional strain and loading experienced by the adaptive implement attached thereto is borne by the foregoing elements, especially due to the asymmetric loading experienced as a result of the independent lateral attachment to the wheelchair 100. The success with which the design, construction, and choice of materials hold up to this anticipated asymmetric strain will impact the performance, safety, and longevity of the apparatus as well as the proper functioning of the mechanism employed to carry out the transitioning thereof through all stages of the operative sequence.

(33) FIG. 3C shows the mounting member 110 having a bearing plate 374 comprising a nested groove 378 and a bearing stop 377 against which the cylindrical bearing element 350 (not shown) momentarily contacts during transitioning of the adaptive implement into the operative state. Loading during the operative stage is substantially focused on the lower bearing surface 376 of the nested groove 378.

(34) During the inoperative state, as well as during transition into and out of the inoperative state, the cylindrical bearing element 350 slides in an arcuate path in contact with or in close proximity to the arcuate bearing surface 396 of the bearing plate 374. The axis 384 of the expanding pin 340 serves as a fulcrum around which the adapting member 120 rotates; the shape of the arcuate bearing surface 396 may thus be defined as an arc having a radius equal to the distance from the axis 384 of the expanding insertion pin 340 to the nearest contact point of the cylindrical bearing element 350 while the load-transfer assembly 310 is in the internal inoperative stage or during transition into or out of the internal inoperative stage. Furthermore, to ensure maximum contact of the cylindrical bearing element 350 with the contact surfaces of the nested groove 378, the deepest point of the nested groove may be defined by the distance from the axis 384 of the expanding insertion pin 340 to the nearest contact point of the cylindrical bearing element 350 while the load-transfer assembly 310 is in the internal operative stage.

(35) During the internal operative stage, as well as during the internal pre-inoperative stage, the cylindrical bearing element 350 is disposed in the nested groove 378 of the bearing plate 374. Upwardly directed force (due to downward loading on the front end of the wheelchair) is leveraged about the axis 384 of the expanding pin 340 and transferred downwardly against the lower bearing surface 376 of the nested groove 378. Supporting of a load by the separable-type adapter 180 relies on the integrity of the elements of the moveable bearing assembly 348 as they transfer the load from the adapting member 120, through the cylindrical bearing element 350 and the arcuate bearing element 352, to the bearing sleeve 356, and finally to the bearing plate 374.

(36) FIGS. 4A through 4D illustrate the positioning of the internal components of the load-transfer assembly 310 and the positioning of the entire adapting member 120 relative to the mounting member 110 during the four internal stages of the operative sequence, the transition through which is effectuated by the user manipulating the input knob 126 and subsequently performing a wheel-stand maneuver or otherwise controllably reclining the wheelchair 100. In this way, the load-transfer assembly 310 transitions in a cyclical fashion from an internal inoperative stage, to an internal pre-operative stage, to an internal operative stage, to an internal pre-inoperative stage, and back to the internal inoperative stage.

(37) The input knob 126, which is intended to be pushed by the user in the rearward direction, is affixed to an input slider 414 which fits snugly and is able to slide smoothly inside the tubular casing 450 of the load-transfer assembly. The input slider 414 is further connected to an input post 412 of a bistable switching mechanism 410 which is prevented from moving within the tubular casing 450 by a set screw 460 penetrating through the tubular casing 450 and pressing against the outer surface of the bistable switching mechanism 410. Linear movement of the input slider 414 produces linear movement of the input post 412 to effectuate a state change in the bistable switching mechanism 410; the bistable switching mechanism 410 toggles between a first state and a second state, which in turn alternates an output rod 408 of the bistable switching mechanism 410 between a protracted position and a retracted position. Connected to the end of the output rod 408 is an output slider 406 which fits snugly and slides smoothly inside the tubular casing 450 and which, likewise, is alternated between a protracted position and a retracted position.

(38) In FIG. 4A, starting with the load-transfer assembly 310 in the internal inoperative stage, that is—with the adapting member 120 attached to the mounting member 110, while non-load-sharing, and prior to the user pushing the input knob 126 in the rearward direction, the output slider 406 is in its most protracted position and, as a result, applies maximum force against a disengagement spring 404, which in turn applies spring pressure against the sliding body 402 of the moveable bearing assembly 348. As the adapting member is rotated about the axis 384 of the expanding insertion pin 340, such as if the user performs a wheel-stand maneuver, the cylindrical bearing element 350, connected to the sliding body 402, remains out of contact, due to the spring pressure from the disengagement spring 404, from the nested groove 378 of the bearing plate 374. For this reason, attaching and releasing of the adapting member 120 to and from the mounting member 110 is made possible during the internal inoperative stage.

(39) Upon the user pressing rearwardly against the input knob 126, the bistable switching mechanism 410 is toggled from the first state to the second state, ultimately resulting in movement of the output slider 406 from the protracted position to its most retracted position and relaxation of compressive force against the disengagement spring 404, thereby placing the load-transfer assembly 310 into the internal pre-operative stage, shown in FIG. 4B, in which it will remain until the user performs a wheel-stand maneuver to move the cylindrical bearing element 350 in an arcuate path along the arcuate bearing surface 396 of the bearing plate 374 toward the nested groove 378.

(40) Upon the user performing the wheel-stand maneuver, thereby effectuating a change in the angular position of the adapting member 120 relative to the mounting member 110, the cylindrical bearing element 350 moves into full contact, within the nested groove 378, with the bearing plate 374. After the user has completed the wheel-stand maneuver and brings the front end of the wheelchair down so that the large caster wheel (not shown) contacts the ground surface, upwardly directed force (due to downward loading on the front end of the wheelchair) is leveraged about the axis 384 of the expanding insertion pin (not shown) and transferred downwardly against the lower bearing surface 376 of the nested groove 378. Movement of the cylindrical bearing element 350 into the nested groove is further promoted by an engagement spring 400, which applies force in the forward direction against the sliding body 402 of the moveable bearing assembly 348. In this way, upon transitioning the load-transfer assembly into the internal operative stage, it will remain in the internal operative stage until the force of the engagement spring 400 is overcome as a result of toggling the bistable switching mechanism 410 from the second state to the first state and subsequently performing a wheel-stand maneuver.

(41) As can be seen in FIGS. 4C and 4D, while the load-transfer assembly 310 is in the internal operative stage, upon toggling the bistable switching mechanism 410 from the second state to the first state, linear urging force is output through the output rod 408 to the output slider 406; this applies rearwardly directed force against the disengagement spring 404, the opposite end of which is in contact with the sliding body 402 of the moveable bearing assembly 348. Compression of the disengagement spring 404, in turn, urges the sliding body 402 in the direction away from the bistable switching mechanism 410. Friction between the contact surfaces of the cylindrical bearing element 350 and the nested groove 378 of the bearing plate 374, as a result of load-bearing by the apparatus, maintains the cylindrical bearing element 350 in contact with the nested groove 378. In this manner, the load-transfer assembly 310 is thus transitioned from the internal operative stage into the internal pre-inoperative stage, and remains so until the user performs a wheel-stand maneuver.

(42) While the load-transfer assembly 310 is in the internal pre-inoperative stage, as in FIG. 4D, subsequent performance of a wheel-stand maneuver by the user substantially reduces any friction maintained between the contact surfaces of the cylindrical bearing element 350 and the nested groove 378 of the bearing plate 374 so as to permit movement of the entire moveable bearing assembly 348, thus disengaging the cylindrical bearing element 350 out of contact within the nested groove 378 and compressing the engagement spring 400. This transitions the load-transfer assembly into the internal inoperative stage; as in FIG. 4A, the output slider 406 is again held by the bistable switching mechanism 410 in its most protracted position and, as a result, applies maximum force against the disengagement spring 404.

(43) As opposed to the separable-type adapter 180 embodied in the figures presented heretofore, FIG. 5 depicts a wheelchair 100 outfitted with an identical pair of inseparable-type adapters 500A and 500B, attached to opposing lateral portions 510A and 510B of the wheelchair 100. Both adapters are shown in the operative position and are equipped with support members 506A and 506B and ski implements 520A and 520B. An alignment collar 504 is shown attached circumferentially to the lateral portion 510A; this serves to maintain an attachment clamp 502 in a predetermined position, both vertically and rotationally relative to the lateral portion 510A and to ensure that through repeated cycles of attachment and detachment to and from the wheelchair, the positioning of the inseparable-type adapter 500A, and the ski implements connected thereto are preserved relative to the wheelchair.

(44) An operative sequence is carried out by the user through manipulation of a rotatable switch 508 and subsequent performance of a wheel-stand maneuver or other action to momentarily and controllably recline the wheelchair backwards. Clockwise rotation of the rotatable switch 508 produces rotational movement of elements within the load-transfer and transitioning assembly 530 to effectuate a state change therein to alternate a clutching mechanism between a first load-transferring state and a second load-transferring state. Alternatively, it may be desirable to configure the load-transfer and transitioning assembly 530 such that clockwise rotation of the rotatable switch 508 instead effectuates a state change to alternate the enclosed clutching mechanism between a load-transferring state and a non-load-transferring state.

(45) While in the internal pre-operative stage, upon rotating the rotatable switch 508 in the clockwise direction, the user pre-disposes the load-transfer and transitioning assembly 530 towards the internal operative stage, whereas while in the internal pre-inoperative stage, rotating the rotatable switch 508 in the counter-clockwise direction, the user pre-disposes the transitioning assembly towards the internal inoperative stage. In both cases, performing of the wheel-stand maneuver thus serves as the catalyst to complete the transition from a pre-disposed stage to the desired load-transferring stage.

(46) Although the apparatus as depicted represents an alternative attachment and transitioning means, the principles of operation are the same in essence, and many of the elements in FIG. 5 are analogous to previously presented elements. For example, the rotatable switch 508 and the transitioning assembly 530 in FIG. 5 are analogous in their function to the input knob 126 and the load-transfer assembly 310 shown in previous figures.

(47) As depicted in FIG. 6, useful combinations of adaptive implements as well as different attachment types may be employed. Shown in FIG. 6 are both the separable- and the inseparable-type attachment and transitioning embodiments, which may be transitioned separately or synchronously, each through its own operative sequence such as that previously described, while attached to opposing lateral portions of the wheelchair 100. Attached to a first side 510A of the wheelchair 100 is a separable-type adapter 180 comprising a mounting member 110 and an adapting member 120 and equipped with a large caster wheel 122. The attachment and transitioning means makes it possible for the user or occupant of the wheelchair 100 to attach the large caster wheel 122, to the wheelchair 100 and to willfully alternate it between an operative state and an inoperative state or, in other words, to transition the large caster wheel implement 120 between an upper vertical position and a lower vertical position relative to the wheelchair 100. In a similar fashion, attached to a second side MOB of the wheelchair 100 is an inseparable-type adapter 500 comprising a clamp 502 and a transitioning assembly 530, to make it possible for the user or occupant to attach a shovel implement 600 to the wheelchair 100 and to willfully alternate it between an operative state and an inoperative state or, in other words, to transition the shovel implement 600 between an upper vertical position and a lower vertical position relative to the wheelchair 100. As illustrated, attachment and deployment of the large caster wheel 122 adds clearance 130 beneath the primary caster wheels 106A and 106B, adds forward stability to the wheelchair, and distributes the load placed on the front end of the wheelchair in order to facilitate the use of the shovel implement 600 while maneuvering the wheelchair 100 over a ground surface and imparting change thereto, in this case through the act of shoveling.

(48) FIGS. 7A and 7B illustrate the inseparable-type adapter 500, and the alignment collar 504, both detached from the wheelchair (not shown). Disposed between a rotatable member 703 of the inseparable-type adapter 500 and an adaptive implement (not shown) is support member 506A. A cylindrical extender 706 welded to a clamp 502, comprising cam-action lever fasteners 730A and 730B, is adjustably secured to the fixed member 702 with collar 710 which is tightened with collar bolt 712. The directional arrow 730 imprinted on the rotatable member 703 indicates the direction in which the rotatable member 703, the support member 506A, and an adaptive implement (not shown) connected thereto will rotate when the inseparable-type adapter 500 is attached to the wheelchair (not shown) and upon the occupant of the wheelchair performing a wheel-stand maneuver. A detent element 704 limits the rotation of the rotatable member 703 in that it does not permit continued rotation of the rotatable member 703 in the direction of the imprinted arrow 730 upon the detent element 704 contacting the detent bar 705. The internal state of the transitioning assembly 530 is alternated upon the user or occupant manipulating the rotatable switch 508 between a clockwise position and a counterclockwise position to bias a plurality of bearing elements either into or out of load-bearing contact with a bearing surface housed within the transitioning assembly 530; in effect, the internal state of the transitioning assembly 530 determines whether or not loading on the front end of the wheelchair (not shown) will be distributed through the clamp 502, the cylindrical extender 706, the transitioning assembly, the support member 506A and the adaptive implement (not shown) to the ground surface (not shown). While in the operative state, the internal bearing elements are biased into load-bearing contact with the internal bearing surface, thus upon the user or occupant controllably reclining the wheelchair to the extent that the detent element 704 contacts the detent bar 705 the rotatable member 703 becomes locked into a fixed position in that it will no longer rotate in either direction due to the wedging action of the internal bearing elements in one direction and the detention by the detent element 704 against the detent bar 705. As a result, the adaptive implement (not shown) connected to the rotatable member 703 is maintained in the operative position until such time that the user or occupant rotates the rotatable switch 508 to the opposite position, to release the urging force placed against the internal bearing elements, and he or she subsequently performs a wheel-stand maneuver or otherwise controllably reclines the wheelchair.

Example

(49) An exemplary apparatus was built and configured for the purpose of lengthening the effective wheelbase of the wheelchair and also for decreasing the rolling resistance experienced by the user, especially while traversing over ground substrates such as sand, gravel, woodchips, grass, and snow. The apparatus comprises a single adaptive caster wheel implement which attaches to the left side of a wheelchair so that it may perform in conjunction with, though operated independently of, any additional adaptive implement that may be usefully attached to the right side of the wheelchair. The apparatus may, alternatively, be attached to the left side of the wheelchair without any adaptive implement attached to the right side of the wheelchair.

(50) While attached to the wheelchair in a unilateral manner, the opposing side of the wheelchair frame remains relatively free from obstruction, thereby enabling a user or occupant of the wheelchair to pass his or her body into or out of a seated position in the wheelchair while the apparatus is attached to the wheelchair, if he or she so desires.

(51) The exemplary apparatus comprises an adapting member comprising a caster assembly that is substantially larger and more robust than the original primary caster assemblies that are permanently integrated with the wheelchair, and includes a 50 mm wide, 8-inch diameter pneumatic tire fitted over an aluminum wheel hub. This tire was chosen because, when inflated, it exhibits excellent rolling resistance on both rugged surfaces and smooth surfaces alike, and provides sufficient grip against paved surfaces to help prevent flutter of the caster assembly when approaching vehicle speeds of around 8 MPH or 12 KmPH, which is average human running speed.

(52) The exemplary apparatus also comprises a mounting member, which is semi-permanently clamped onto a forward lateral support of the frame of the wheelchair such that it occupies the space immediately above the left-side primary caster assembly of the wheelchair. The mounting member remains affixed to the wheelchair at all times and is unobtrusive to the user's arms, legs, and feet, and outerwear at times when an adapting member is decoupled from the mounting member.

(53) The mounting member comprises two tube clamps and a primary structural plate; all fabricated out of 6061 aluminum and secured using stainless steel machine screws. A hollow receiver socket, comprising a threaded outer surface, is secured inside an opening cut through the primary structural plate by tightening threaded nuts on opposing sides of the hollow receiver socket. A bearing element, composed of aluminum bronze and comprising four adjustment holes, is affixed to the primary structural plate and is secured against the primary structural plate by one of the threaded nuts and is rotationally secured by a bearing fastening bolt. Loosening of the bearing fastening bolt permits rotation of the bearing element about the axis of the hollow receiver socket; a defined operation angle of the adapting member is dependent upon which adjustment hole is occupied by the bearing fastening bolt in securing the bearing element to the primary structural plate.

(54) The bearing element of the mounting member further comprises a disengagement region and a nested engagement region, both which have been ground and polished to allow for a moveable bearing element of the adapting member to slide smoothly along the disengagement region and into and out of the nested engagement region.

(55) The adapting member is primarily composed of 6061 aluminum, and comprises several position adjustment means. First, the position of the caster assembly is connected to and may be rotatably and longitudinally adjusted relative to a curved support arm. Second the support arm is connected to and rotatably and longitudinally adjustable relative to a solid connector body. Third, the curved support arm itself serves as a means for changing the effective pitch orientation of the caster assembly.

(56) The adapting member further comprises a protract-retract mechanism which is contained within a tubular housing body, the tubular housing body bolted to the solid connector body. An outer portion of the protract-retract mechanism is affixed to the inner surface of the tubular housing body with a set screw. The protract-retract mechanism is slidingly toggled by the user or occupant by pushing rearwardly against a slider knob. Movement of an input element of the protract-retract mechanism switches an output element between a protracted position and a retracted position which, in turn, alternates an internal slider, composed of low-friction wear-resistant Nylatron® rod, between a first position and a second position. While in the first position, the internal slider applies linear pressure against the moveable bearing element to urge it towards a disengaged position. If the apparatus is currently in an operative state, toggling the internal slider to the first position will pre-dispose the moveable bearing element to move into the disengaged position to occupy the disengagement region at the instant the user or occupant performs a wheel-stand maneuver or otherwise elevates the front end of the wheelchair.

(57) While in the second position, the internal slider removes linear pressure against the moveable bearing element and thus permits it to move towards an engaged position. If the apparatus is currently in an inoperative state, toggling the internal slider to the second position will pre-dispose the moveable bearing element to move into the engaged position to occupy the nested engagement region at the instant the user or occupant performs a wheel-stand maneuver or otherwise elevates the front end of the wheelchair.

(58) The speed and force with which the moveable bearing element moves into and out of the nested engagement region depends largely on the amount of biasing force that is applied against the moveable bearing element in either direction. In the case of the exemplary apparatus, two internal extension springs, disposed on opposite sides of the moveable bearing element, were selected according to characteristics (length, diameter, and extension force) that would produce maximum travel, urging force, and speed in both directions upon the user or occupant toggling the internal slider between the first position and the second position and performing a wheel-stand maneuver or otherwise elevating the front end of the wheelchair. Through experimentation, it was observed that if the spring forces applied to opposing sides of the moveable bearing element were not properly balanced, the moveable bearing element would fail to move into or out of the nested engagement region upon toggling the internal slider and performing a wheel-stand. Once this balance was achieved, however, the apparatus has demonstrated very reliable operation with only occasional cleaning and lubrication necessary.

(59) An insertion pin with a diameter of ½ inch, integrated with the adapting member, is removeably insertable into the hollow receiver socket of the mounting member, which comprises a smooth interior surface. Upon full insertion, the adapting member is situated in the correct lateral position relative to the wheelchair, and the moveable bearing element of the adapting member is situated in the correct location against the disengagement region of the bearing element. To further enhance the integrity of the connection of the adapting member to the mounting member, the insertion pin comprises expandable rings which are expanded within the hollow receiver socket upon the user or occupant applying force against a cam-action lever handle operatively connected to an inner rod of the insertion pin. The user or occupant, upon coupling the insertion pin into the hollow receiver socket, actuating the protract-retract mechanism, and performing a wheel-stand, may enhance the grip of the coupling by applying force against the cam-action lever handle in order to use the apparatus in rigid union with the wheelchair so that minimal “wiggle” or “play” is observed between the mounting member and the adapting member.

(60) The exemplary apparatus has been used in conjunction with an Invacare Top End titanium rigid-style wheelchair, and has performed exceptionally well on outdoor surfaces including sand, gravel, wood chips, smooth pavement, rugged weathered pavement, city sidewalks, and snowy neighborhood streets.

(61) The user, having a complete spinal cord injury at the level of the sixth thoracic vertebra, has no motor or sensory function in his legs and in the lower half of his torso. As a result, situating himself correctly in his wheelchair requires the act of “transferring” his body, using his upper body strength to lift himself from one seated surface, such as a car seat, a couch, a bed, or up from the floor and, depending on the surface from which the user is transferring from, this action further involves the passive use of his legs and feet to serve as an anchor for the purpose of safely and controllably pivoting his weight around to complete the transfer. It has been to this particular user's advantage to be very selective in choosing when it is worth the time, strain and energy expenditure to perform any transfer; the exemplary apparatus has been convenient for the user because he is able to remain seated in his wheelchair during the process of converting his wheelchair between adaptive modes.

(62) The user has benefited from the smoother riding characteristics and the added forward stability that result from attachment of the apparatus to his wheelchair, in that it has helped him to entirely avoid being forwardly tumbled or ejected from the seated position. The user has furthermore been able to allocate more time towards enjoying and viewing the surrounding landscape while propelling the wheelchair forward, such as around his neighborhood or at a nearby state park, and less time towards observing and avoiding the small bumps, cracks, tree roots, and other obstacles that would otherwise put him at risk of falling out of his wheelchair.

(63) Actuating the biasing mechanism (to pre-dispose the load-transfer assembly toward the opposite load-bearing state) is quick and easy for the user to perform, as the actuator knob is well within arm's reach.

(64) To convert the wheelchair from its original mode to the adapted mode, the user inserts the expanding pin of the adapting member into the receptacle of the mounting member and, after manually actuating the biasing mechanism, he effectuates the transition to the adapted mode by reclining the wheelchair backward so that the primary caster wheels of the wheelchair are elevated approximately 1½ inches above the ground surface. An audible “click” is heard as the moveable bearing element moves into the nested engagement region of the bearing surface. The user then further secures the adapting member to the mounting member by pulling the cam-action expansion pin lever in towards the body of the adapting member. The caster wheels remain elevated approximately 1½ inches above the ground surface during travel in all directions and do not add rolling resistance or otherwise interfere with the performance of the wheelchair in its adapted mode, as the large forward caster wheel now shares, with the wheelchair, the load distributed towards the front of the wheelchair. As a result, the user has been able to use his adapted everyday wheelchair to venture out with relative ease over terrain such as at parks, playgrounds, trails, and over heavily weathered pavement, all which would otherwise pose significant difficulty and safety risk. The user has furthermore enjoyed the maneuverability, in all directions of travel, afforded by the adapted wheelchair while the user traverses over both indoor and outdoor surfaces.

REMARKS

(65) The foregoing described embodiments depict different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as “associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being “operably connected,” or “operably coupled,” to each other to achieve the desired functionality.

(66) When introducing elements of aspects of the invention or the embodiments thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

(67) Having described aspects of the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of aspects of the invention as defined in the appended claims. As various changes could be made in the above compositions, products, and methods without departing from the scope of aspects of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. Reference to particular illustrative embodiments should not be construed as limitations. The inventive devices, products, and methods can be adapted for other uses or provided in other forms not explicitly listed above, and can be modified in numerous ways within the spirit of the present disclosure. Thus, the present invention is not limited to the disclosed embodiments.