Unilateral transition means for adapting a wheelchair

Abstract

Transition means for adapting a wheelchair are 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. An apparatus capable of unilateral attachment to a wheelchair for alternating the 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 frame comprising a pair of symmetrically-opposing lateral portions, the apparatus capable of being operatively interposed between an implement assembly and one of the pair of symmetrically-opposing lateral portions of the frame of the wheelchair, the apparatus comprising a bearing and a bearing surface, the bearing and the bearing surface capable of rotating relative to each other about a substantially horizontal axis, the bearing and the bearing surface capable of engagement in load-bearing contact with each other, the bearing and the bearing surface further capable of disengagement from load-bearing contact with each other, the apparatus further comprising a switch mechanism comprising a disengagement spring, the switch mechanism capable of toggling between: a. a first state having the disengagement spring assuming a relaxed form, corresponding to preparing of the apparatus for engagement of the bearing and the bearing surface in load-bearing contact with each other to place the wheelchair in the second load-bearing configuration, and b. a second state having the disengagement spring assuming a deflected form, corresponding to preparing of the apparatus for disengagement of the bearing and the bearing surface from load-bearing contact with each other to place the wheelchair in the first load-bearing configuration, wherein, while the wheelchair is in the first load-bearing configuration, the pair of forward caster wheels of the wheelchair support a forward portion of a load supported by the wheelchair and, while the wheelchair is in the second load-bearing configuration, the implement assembly supports the forward portion of the load supported by the wheelchair.

2. The apparatus of claim 1, said bearing being substantially cylindrical, and said bearing surface being substantially arcuate.

3. The apparatus of claim 1, wherein while the wheelchair is in the first load-bearing configuration, actuating the switch mechanism causes the apparatus to become responsive to reclining of the wheelchair by enabling transitioning of the bearing and the bearing surface toward a relative disposition of engagement, and while the wheelchair is in the second load-bearing configuration, actuating the switch mechanism causes the apparatus to become responsive to reclining of the wheelchair by enabling transitioning of the bearing and the bearing surface away from the relative disposition of engagement.

4. The apparatus of claim 1, wherein reclining of the wheelchair enables lowering of a rotatable portion of the apparatus in a downward direction, corresponding to relative rotation between the bearing and the bearing surface about the substantially horizontal axis.

5. The apparatus of claim 4, further configured to restrict downward rotation of the rotatable portion of the apparatus, wherein, during transitioning of the wheelchair to the second load-bearing configuration, the rotatable portion rotates in the downward direction relative to the frame of the wheelchair by a predetermined degree of rotation, corresponding to relative rotation between the bearing and the bearing surface by the predetermined degree of rotation about the substantially horizontal axis.

6. The apparatus of claim 1 wherein, while the wheelchair is in the first load-bearing configuration, the bearing and the bearing surface are maintained out of load-bearing engagement, and the pair of forward caster wheels of the wheelchair are contacting a ground surface beneath the wheelchair and the pair of forward caster wheels are bearing a forward portion of a load supported by the wheelchair and, while the wheelchair is in the second load-bearing configuration, the bearing and the bearing surface are maintained in load-bearing engagement to transmit the forward portion of the load supported by the wheelchair to the implement assembly, and the pair of forward caster wheels of the wheelchair are elevated from contact with the ground surface beneath the wheelchair.

7. The apparatus of claim 1, wherein while the wheelchair is in the first load-bearing configuration, the bearing and the bearing surface remain out of load-bearing engagement upon toggling of the switch mechanism from the first state to the second state until relative rotation is achieved between the bearing and the bearing surface in a forward direction as a result of reclining the wheelchair to enable engagement of the bearing with the bearing surface.

8. The apparatus of claim 1 wherein, while the wheelchair is in the second load-bearing configuration, the bearing and the bearing surface remain in load-bearing engagement upon toggling of the switch mechanism from the second state to the first state until friction between the bearing and the bearing surface becomes substantially reduced as a result of reclining the wheelchair, resulting in: release of the bearing and the bearing surface from load-bearing engagement, relative rotation between the bearing and the bearing surface in a reverse direction of rotation, raising of the implement assembly upward, and lowering of the forward caster wheels of the wheelchair into contact with the ground surface beneath the wheelchair.

9. The apparatus of claim 1, further comprising an engagement spring capable of applying a forward sustaining force to impart relative movement of the bearing and the bearing surface toward each other to achieve load-bearing engagement upon relative rotation between the bearing and the bearing surface as a result of reclining the wheelchair rearward, the first state corresponding to a deflected form of the engagement spring to prepare the apparatus to transition from the first load-bearing configuration to the second load-bearing configuration, the deflected form of the engagement spring applying the forward sustaining force to impart relative movement of the bearing and the bearing surface toward each other to achieve engagement thereof, the second state corresponding to a relaxed form of the engagement spring to prepare the apparatus to transition from the second load-bearing configuration to the first load-bearing configuration, the relaxed form of the engagement spring permitting relative movement of the bearing and the bearing surface away from each other to achieve disengagement thereof.

10. The apparatus of claim 1, the disengagement spring capable of applying a reverse sustaining force to prepare the apparatus for relative movement of the bearing and the bearing surface out of engagement with each other as a result of reclining the wheelchair rearward, the first state corresponding to a relaxed form of the disengagement spring to prepare the apparatus to transition from the first load-bearing configuration to the second load-bearing configuration, the relaxed form of the disengagement spring permitting relative movement of the bearing and the bearing surface toward each other to achieve engagement thereof, the second state corresponding to a deflected form of the disengagement spring to prepare the apparatus to transition from the second load-bearing configuration to the first load-bearing configuration, the deflected form of the disengagement spring applying the reverse sustaining force to impart relative movement of the bearing and the bearing surface away from each other to achieve disengagement thereof.

11. The apparatus of claim 10, further comprising an engagement spring capable of applying a forward sustaining force to impart relative movement of the bearing and the bearing surface toward each other to achieve load-bearing engagement upon relative rotation between the bearing and the bearing surface as a result of reclining the wheelchair rearward, the first state corresponding to a deflected form of the engagement spring to prepare the apparatus to transition from the first load-bearing configuration to the second load-bearing configuration, the deflected form of the engagement spring applying the forward sustaining force to impart relative movement of the bearing and the bearing surface toward each other to achieve engagement thereof, the second state corresponding to a relaxed form of the engagement spring to prepare the apparatus to transition from the second load-bearing configuration to the first load-bearing configuration, the relaxed form of the engagement spring permitting relative movement of the bearing and the bearing surface away from each other to achieve disengagement thereof.

12. The apparatus of claim 1 capable of being integrated with the wheelchair.

13. The apparatus of claim 1, the implement assembly comprising a wheel.

14. The apparatus of claim 1 capable of operation as one of a pair of apparatuses while each one of the pair of apparatuses is connected separately to one of the pair of symmetrically-opposing lateral portions of the frame of the wheelchair.

15. An apparatus adapted for integration with a wheelchair for alternating the 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 comprising a pair of symmetrically-opposing lateral portions, the apparatus capable of being operatively interposed between one of the pair of symmetrically-opposing lateral portions of the frame of the wheelchair and a ground-contacting adaptive implement, the apparatus comprising a bearing and a bearing surface, the bearing and the bearing surface capable of relative rotation about a substantially horizontal axis, the bearing and the bearing surface further capable of engagement in load-bearing contact with each other, the bearing and the bearing surface further capable of disengagement from load-bearing contact with each other, the apparatus further comprising a switch mechanism comprising a spring capable of assuming a relaxed form corresponding with engaging of the bearing and the bearing surface, the spring further capable of assuming a deflected form corresponding with disengaging of the bearing and the bearing surface, the switch mechanism capable of toggling between: a. a first state having the spring assuming the relaxed form, corresponding with preparing of the apparatus for sustained engagement of the bearing and the bearing surface in load-bearing contact with each other to place the wheelchair in the second load-bearing configuration, b. a second state having the spring assuming the deflected form, corresponding with preparing of the apparatus for disengagement of the bearing and the bearing surface from load-bearing contact with each other to place the wheelchair in the first load-bearing configuration.

16. The apparatus of claim 15 being operable as one of a pair of apparatuses capable of being connected separately to one of the pair of symmetrically-opposing lateral portions of the frame of the wheelchair.

17. A load transitioning system adapted to be integrated with a wheelchair, the wheelchair comprising a frame, a pair of rear drive wheels, and a pair of conventional caster wheels, the load transitioning system capable of deploying a forward wheel apparatus to extend the effective wheelbase of the wheelchair, the forward wheel apparatus capable of being removably connected to the frame of the wheelchair, the load transitioning system adapted to alternate support of a forward portion of a load carried by the wheelchair between the forward wheel apparatus and the pair of conventional caster wheels, the load transitioning system further adapted to transition the wheelchair between: a first load-bearing configuration utilizing the pair of conventional caster wheels for navigation of the wheelchair, and a second load-bearing configuration utilizing the forward wheel apparatus for navigation of the wheelchair, the load transitioning system further comprising a switch mechanism, the switch mechanism comprising a spring capable of assuming a relaxed form corresponding with engaging of the bearing and the bearing surface, the spring further capable of assuming a deflected form corresponding with disengaging of the bearing and the bearing surface.

18. The load transitioning system of claim 17, the switch mechanism capable of toggling between a first state and a second state, the first state corresponding with preparing for engagement of the bearing and the bearing surface with each other and for transitioning of the wheelchair from the first load-bearing configuration to the second load-bearing configuration, the second state corresponding with preparing for disengagement of the bearing and the bearing surface from each other and for transitioning of the wheelchair from the second load-bearing configuration to the first load-bearing configuration, wherein, while the wheelchair is in the first load-bearing configuration, toggling of the switch mechanism and subsequent reclining of the wheelchair transitions the wheelchair to the second load-bearing configuration and while the wheelchair is in the second load-bearing configuration, toggling of the switch mechanism and subsequent reclining of the wheelchair transitions the wheelchair to the first load-bearing configuration.

19. The load transitioning system of claim 18, the switch mechanism further comprising a second spring capable of assuming a deflected form corresponding with engaging of the bearing and the bearing surface, the second spring further capable of assuming a relaxed form corresponding with disengaging of the bearing and the bearing surface.

20. The load transitioning system of claim 17, forming a joint defining a substantially horizontal rotation axis, the forward wheel apparatus capable of rotating downwardly about the substantially horizontal rotation axis during transitioning of the wheelchair from the first load-bearing configuration to the second load-bearing configuration, the forward wheel apparatus capable of rotating upwardly about the substantially horizontal rotation axis during transitioning of the wheelchair from the second load-bearing configuration to the first load-bearing configuration, the joint being operatively interposed between the frame of the wheelchair and the forward wheel apparatus, the joint comprising a fixed portion adapted to be affixed to the frame of the wheelchair, the joint further comprising a rotatable portion connected to the forward wheel apparatus, the rotatable portion capable of rotating relative to the fixed portion during transitioning of the wheelchair between the first load-bearing configuration and the second load-bearing configuration, the bearing of the load transitioning system being inseparably connected to one of the frame of the wheelchair or to the forward wheel apparatus, the bearing surface of the load transitioning system being inseparably connected to the other of the frame of the wheelchair or to the forward wheel apparatus.

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 iswith 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 5108 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 510B 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 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 1 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 1 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.

(65) Remarks

(66) 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.

(67) 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.

(68) 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.