Patent Application
20130257009
The present invention relates to wheelchairs and other wheeled apparatuses.
Because wheelchairs must have a high degree of stability when their users traverse sloped surfaces or effect rapid turns, traditional wheelchairs with fixed wheelbase dimensions are designed with suitably large wheelbase dimensions. But a wheelchair with fixed wheelbase dimensions is an impediment to wheelchair users in many contexts. For example, maneuvering into small washrooms, around cramped office quarters, and through the interior doors of most homes is often impossible. Additionally, standard wheelchairs with a large, fixed wheelbase dimension will not ordinarily pass down an airliner aisle. As a result, the user must necessarily transfer from a traditional fixed wheelbase wheelchair to one of the airline's uncomfortable and humiliating “people dollies.”
Attempts have been made to address these problems by developing wheelchairs with an adjustable wheelbase, but such wheelchairs enable only incremental and semi-permanent adjustments, not the type of ad hoc, easily reversible, on-the-fly adjustments which are necessary when dealing with obstacles which can only be, or can more easily be, traversed by a wheelchair with a narrower wheelbase.
In accordance with the teachings of the present disclosure, the disadvantages and problems associated with traditional fixed wheelbase wheelchairs have been substantially reduced or eliminated.
In embodiments of the present disclosure, an apparatus for use as a wheelchair chassis may include a first side frame and a second side frame. The second side frame may be positioned substantially parallel to the first side frame at a width apart from the first side frame. The apparatus may also include a first receiver tube, which may be positioned substantially parallel to the first side frame and coupled to the first side frame, as well as a second receiver tube, which may be positioned substantially parallel to the second side frame and coupled to the second side frame. The apparatus may additionally include a first extension tube, which may be telescopically engaged with the first receiver tube, and a second extension tube, which may be telescopically engaged with the second receiver tube. The apparatus may further include a first cross member, which may be pivotally coupled to the first receiver tube and the second extension tube, as well as a second cross member, which may be pivotally coupled to the second receiver tube and the first extension tube.
Additionally, the second cross member may be engaged to the first cross member in an X-shaped configuration disposed horizontally between the first side frame and the second side frame, where the second cross member is substantially co-planar with the first cross member.
In these and other embodiments of the present disclosure, an apparatus for use as a wheelchair chassis may include the first side frame and the second side frame each having a forward and a rearward terminus. The first receiver tube may be substantially centered between the first side frame forward terminus and the first side frame rearward terminus. The second receiver tube may be substantially centered between the second side frame forward terminus and the second side frame rearward terminus. The apparatus may additionally include the first and second extension tubes having a forward terminus and a rearward terminus. The first extension tube rearward terminus may be telescopically engaged with the first receiver tube, while the first extension tube forward terminus extends toward the first side frame forward terminus. Similarly, the second extension tube rearward terminus may be telescopically engaged with the second receiver, while the second extension tube forward terminus extends toward the second side frame forward terminus.
A more complete and thorough understanding of the presently disclosed embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein:
Preferred embodiments of the invention and its advantages are best understood by reference to
Referring to
Referring primarily to
Referring primarily to
It will be understood by one of skill in the art that the term tube as used to refer to receiver tubes 26 and extension tubes 28 is not limited to an element of circular cross-section. As commonly used in the art, the term tube describes a hollow, elongated body with a polygonal or elliptical cross-section. Thus, the term tube may refer to an element with a cross-section that is circular, elliptical, square, rectangular, triangular, etc.
Wheelchair chassis 12 may also include two extension tubes 28, each of which may be telescopically engaged with a corresponding receiver tube 26. In some embodiments, the rearward terminus of each extension tube 28 may be telescopically engaged with the corresponding receiver tube 26, while the forward terminus of each extension tube 28 may extend toward the forward terminus of the corresponding side frame 20.
Wheelchair chassis 12 may additionally include two cross members 22. Each of the cross members 22 may be pivotally coupled to one of the receiver tubes 26 and one of the extension tubes 28, such that the two cross members 22 are arranged in an X-shaped configuration. In some embodiments, the cross members 22 may be coupled in an X-shaped fashion such that each cross member 22 is coupled to the rearward terminus of one of the receiver tubes 26 and the forward terminus of one of the extension tubes 28. In addition, or alternatively, the cross members 22 may intersect at a hub 24. The cross-members 22 may pivot about the hub 24 in a scissor-like manner as the width of the wheelchair chassis 12 is adjusted. In these and other embodiments, the hub 24 may be substantially equidistant from the two side frames 20 and from the forward and rearward termini of the two side frames 20. In this configuration, the hub 24 is substantially centered within the wheelchair chassis 12, rather than positioned toward the rear of the chassis as in U.S. Pat. No. 5,782,483.
With reference primarily to
Some embodiments may include a caster locking mechanism (not shown in the drawings), which may be used in the event that a user of wheelchair chassis 12 lacks the strength to effect an adequate compressive or expansive force to contract or expand the wheelbase dimension of the wheelchair chassis 12. Through the use of an actuator, the caster locking mechanism may be caused to effect a “toe-in” orientation of the caster wheel assemblies 14. When so actuated, forward motion of wheelchair chassis 12 will necessarily effect a contraction of the wheelbase dimension of wheelchair chassis 12, and rearward motion will effect the converse.
Notwithstanding the dynamics of the compressive and expansive forces required to contract and expand the wheelbase dimension of the wheelchair chassis 12, side frames 20 may remain securely linked and the structural integrity of wheelchair chassis 12 is not changed. Because both the forward and rearward termini of receiver tubes 26 may be rigidly coupled to side frames 20, cross members 22 may move pivotally in a single plane. The pivotal motion of cross members 22 may thus permit easy, on-the-fly contraction and expansion of the wheelbase dimension of wheelchair chassis 12 while supporting the side frames 20 in the desired, parallel orientation shown in all the figures. Without this support, the side frames 20 would tend to collapse under the torque applied by the weight of a rider. No other known wheelchair design affords these capabilities simultaneously.
The torque applied by the weight of the rider may be further counteracted by the positioning of the hub 24, which may be substantially centered within wheelchair chassis 12. In this configuration, the torque applied by the weight of the rider may be equally distributed from front to back, which may reduce the tendency of the forward termini of the side frames 20 to toe-in toward the center of the chassis.
Wheelchairs of known designs either expand and contract in increments effected by complex and semi-permanent adjustments or provide very unstable chassis characteristics. To the applicant's knowledge, only the present disclosure provides a stable, easy to use wheelchair with on-the-fly adjustment of wheelbase dimensions.
Although the present disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. It is important to note that the present disclosure has application beyond the field of wheelchairs. The vehicle chassis described herein could be incorporated into any number of wheeled vehicles, carts, automobiles, and/or other equipment for which it would be advantageous to provide an adjustable wheelbase.
One example of an application of the present disclosure which is extremely far afield of the wheelchair art would be that of an industrial crane. An expansive wheelbase is desirable for most cranes, but the wheelbase dimensions are quite limited for vehicle-based cranes which must travel by roadways. The traditional solution for providing an industrial crane with a more stable base is to use outriggers. But outriggers impede ready movement of the crane once they are extended. Use of the disclosed vehicle chassis design would address this problem by permitting on-the-fly adjustment of wheelbase dimensions, which could be expanded for stability and contracted for mobility.
Additionally, the vehicle chassis of the present disclosure could be incorporated into a three-wheeled vehicle. One version of such a vehicle (not shown in the drawings) might exhibit extension tubes 28 which converge to join with a single caster wheel assembly 14. Provided that a sufficient length of the extension tubes 28 remain straight before convergence, normal interaction between the extension tubes 28 and receiver tubes 26 would be enabled and the same pivoting motion of cross members 22 as described herein would be possible.
Additionally, it should be understood that various changes, substitutions and alternations can be made herein without departing from the spirit and scope of the invention as defined by the following claims.
