WHEELCHAIR WHEEL LOCK LEVER ASSEMBLY

A lever assembly for a wheelchair having a wheel lock system with two wheel lock assemblies. Each wheel lock assembly including a wheel lock and an actuator with an actuation cable that controllably moves a lock-pin between a locking and an unlocking position relative to the wheelchair wheels. The lever assembly has a body and a lever, with the body attached to the wheelchair and both actuation cables, and the lever attached to and controlling both actuation cables to manipulate the lock-pins to engage or disengage the wheelchair wheels. The lever is adapted for use by disabled occupants.

Not applicable.

BACKGROUND OF THE INVENTION

This invention relates principally to a lever for remotely engaging and disengaging a wheel lock, and more particularly to a robust hand-actuated lever assembly for remotely engaging and disengaging a hand-actuated wheel lock for a wheelchair.

The present disclosure comprises improvements to the disclosure presented in U.S. Pat. No. 6,341,671 to Ebersole for a WHEELCHAIR PARKING BRAKE (the '671 Patent), as well as improvements over the commercial version of the wheelchair parking brake in part disclosed and claimed in the '671 Patent. As explained in the '671 Patent: “Existing wheelchair wheel locks based on friction between a moveable portion of a brake, or lock, and the tire or wheel of the wheelchair suffer in effectiveness in that a limited area of contact between the brake and the wheel permit the wheel to slip and rotate under high lateral loads, such as during the egress of the wheelchair occupant from the wheelchair. It is desirable that wheelchair parking brake, or lock, should substantially preclude any further wheel rotation whatsoever, once engaged, nonetheless to being easy and reliable to engage and dis-engage.” ('671 Patent at 1:13-22). The '671 Patent discloses a wheelchair wheel system that overcomes such concerns.

However, the wheelchair parking brake or wheel lock system of the '671 Patent and the commercial wheelchair brake systems that have claimed to be covered by the '671 Patent (collectively, the “Ebersole Design”), incorporate several design features that adversely impact the operation and/or durability of the lock system.

For example, for most wheelchairs, each of the two rear wheels rotate independently of the other. Thus, for security and safety reasons, it is important that both wheels be controlled by the person sitting in the wheelchair when locking the wheelchair. Otherwise, should only one rear wheel be immobilized by a lock, the second rear wheel will be free to rotate and thereby allow the wheelchair to pivot uncontrollably about the rear wheel that is immobilized. This constitutes a serious safety hazard for the wheelchair occupant.

It has accordingly been recognized that providing a wheel lock that only engages one rear wheel of a wheelchair is insufficient in that it does not satisfactorily immobilize that wheelchair. Consequently, the commercial version of the Ebersole Design is constructed of two “bookend” wheel locks—one for each rear wheel—that are each connected by cable to a cable “splitter”. The cable splitter attaches those two cables to a single cable that then attaches to a single lever near the front of the wheelchair. The single lever is therefore able to simultaneously activate both rear wheel locks. Unfortunately, it has been found that: (i) this cabling configuration of the commercial version of the Ebersole Design routinely breaks and/or binds; and (ii) both wheel locks become inoperable should the single cable that attaches to the lever break or otherwise become inoperable itself. Both of these conditions constitute potential safety hazards for the wheelchair occupant.

Further, the Ebersole Design also suffers from the configuration of its lever, which fails to consider possible limitations of a wheelchair occupant. That is, the Ebersole Design lever comprises an open-ended arm or lever that activates the wheel locks. Unfortunately, many individuals confined to wheelchairs suffer from restricted or constrained use of arms, hands and digits, which can result in their inability to readily grasp or manipulate many simple hand devices, such as an open or straight lever arm. This can make utilization of the Ebersole Design lever configuration problematic.

In addition, the Ebersole Design lever pivot mechanism tends to loosen and even disassemble during use. This can cause the lever to become inoperable or even fall apart. This, again, presents a potential safety hazard for the wheelchair occupant.

It would therefore be desirable to have a wheelchair wheel lock system that incorporates a lever and cable assembly that does not suffer the above-described deficiencies. As will become evident in this disclosure, the present invention provides such improvements over the existing art, and in particular, the Ebersole Design.

DETAILED DESCRIPTION

The following detailed description illustrates the claimed invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the disclosure, describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, including what is presently believed to be the best mode of carrying out the claimed invention. Additionally, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

In referring to the Figures, a first representative embodiment of the present disclosure, generally referred to as a wheelchair wheel lock lever assembly10, is shown by way of example inFIGS. 1-5. As can be seen, the lever assembly10, constructed primarily of high-strength polymers along with various metal components, has a polymer body12, a downward directed polymer lever14that is rotatably attached to and descends from the underside of the body12, and a Nylon tube strap16that is attached to and extends upwardly from the top of the body12. The tube strap16releasably attaches to a tube frame or other accessible frame structure of a wheelchair (not shown), preferably under or next to the wheelchair seat, in order to secure the lever assembly10to the wheelchair in a position where it is readily accessible to the wheelchair occupant.

The body12has three integrated elements—a front element18, a central element20and a rear element22opposite the front element18. The front element18is a vertically-oriented generally flat disc, approximately one inch thick, that extends forward and slightly downward at an angle of approximately 30-45 degrees from the central element20. A vertically-oriented disc-shaped slot19a(FIG. 4), having a uniform width of approximately ⅜ inches, substantially bisects the forward-lower portion of front element18, while leaving a bridge19balong the upper rearward portion between each side of the front element18. In this way, the slot19acreates two “bookend” disc-shaped tabs19con each side of the front element18.

The central element20has a generally elongated cubic shape, approximately one inch thick by two inches long by one inch tall, with a generally horizontally-aligned flat top, but having an inverted “V” cross-channel24formed across its underside and a shallow arcuate trough or channel25extending along the length of its top side. Recessed detents26are formed in each side of the central element20at opposing ends of a horizontal hexagonal through bore28that extends laterally through the upper end of the central element20. The bore28snugly houses a steel hexagonal extension nut30into which is threaded into each end a of matching bolt32. The bolts32secure the tube strap16to the central element20.

More specifically, the tube strap16has a thickness of approximately ¼ inch, a uniform width of ¾ to 1¼ inch. The tube strap16includes a circular portion17, having a diameter of approximately one inch when in a state of rest, and two end-rounded attachment tabs34, each extending downward from opposite ends of the circular portion17and each having a hole36centered at the bottom of the tab. The tabs34are each sized and shaped to fit snugly into, and flush against, the inner sides of the corresponding detents26at the sides of the central element20. Each of the bolts32is positioned through one of the two holes36in the tabs34of the tube strap16, and then threaded into a corresponding end of the extension nut30positioned in the bore28. The screws32thereby readily and removably secure the tube strap16to the top of the central element20as shown such that the tube strap16extends substantially vertically above and perpendicular to the shallow channel25atop the central element20. The holes36may alternatively be slotted to provide adjustability to the tube straps16when attaching to the wheelchair.

A stainless-steel hex head bolt40extends through a matching horizontal through bore42in the front element18of the body12in the circular center of each of the two “bookend” disc-shaped tabs19con each side of the front element18. The bore42is shaped and sized to snugly receive the threaded shaft of the bolt40, and the shaft of the bolt40has length that penetrates entirely through the bore42and extends approximately one quarter inch beyond the bore42on the opposite side of the front element18. A stainless-steel nut44is sized and threaded to thread on and secure to the shaft of the bolt40. A hex-shaped depression or detent46in one side of the front element18is centrally oriented about the bore42and shaped to snugly receive the head of the bolt40. The opposite side of the body12about the bore42has a generally flat surface48(not shown) perpendicular to the bore42.

The rear element22of the body12extends approximately ¾ inch rearward from the lower end of the central element20to form a rectangular horizontal ledge. The upper surface of rear element22has three ¼ inch wide flat faces—a horizontal central face50a,and two opposed “bookend” sloping side faces50band50cthat each extend downward from the central face50aat an angle of approximately 10 degrees. A ⅛ inch deep and 3/16 inch wide linear groove51extends longitudinally and centrally across the central face50a.Two small perpendicular through bores52are formed in the groove51, each longitudinally centered in the groove51and separated by approximately ¼ inch. The underside of the rear element20is flat and horizontal, but has two small, parallel longitudinal grooves54that are aligned parallel to, but to either side of, the groove51.

The underside of central element20mates with a matching generally flat and rectangular polymer lower plate56. The lower plate56has two parallel grooves58formed in its upper surface that mate with the grooves54, such that when the lower plate56is properly oriented and pressed against the underside of the rear element22, the grooves54and58align to form a pair of parallel bores running toward the underside of the central element20of the body12. Two small perpendicular through bores62mate with the bores52when the lower plate56is properly oriented and positioned against the underside of the rear element22. A pair of small bolts60and matching nuts64are positioned in the bores52and62to properly align and secure the lower plate56to the rear element22.

The lever14is generally flat with a thickness of approximately ⅜ inches. The lever14includes a large lower circular “ring-shaped” grip70with a diameter of approximately 1½ inches, and a smaller upper circular bore72with a diameter of approximately ¾ inches. As can be appreciated, the grip70is formed of two conjoined legs71aand71b(seeFIGS. 1, 2), which each provides an opposing inner surface against which the wheelchair occupant can exert pressure or force against the grip70to operate the lever14.

A central trunk74extends between and attaches the upper end of the lower grip70and the lower end of the upper circular bore72. The upper circular bore72has a center through bore76having a diameter of approximately ¼ inch. A short, cylindrical metal sleeve78is shaped and sized to fit snugly through the bore76to reinforce the bore76. The length of the sleeve78matches the width of the upper circular bore72.

The upper circular bore72, housing the sleeve78in its center bore76, has a diameter that substantially matches that of the front element18of the body12, and is shaped and sized to cradle in the vertically-oriented disc-shaped slot19. When properly positioned in the slot19, the center bore76and the sleeve78horizontally align with the through bore42such that the bolt40extends through the sleeve78and center bore76of the lever14when the bolt40passes through the bore42. In this way, the lever14rotatably attaches to, while extending downward from, the front element18of the body12.

When the bolt40is positioned in and fully extended through the bore42, the head of the bolt40seats in the hex-shaped detent46, and the nut44can be tightened on the shaft of the bolt40to hold the bolt40in the bore42while maintaining the head of the bolt40in the hex-shaped detent46. As can be appreciated, the nut44must be sufficiently tightened so as to prevent the lever14from automatically rotating about the bolt40due to inherent tensions in the cables, yet slack enough to allow a user to controllably rotate the lever14about the bolt40to actuate the lever assembly10. As can also be appreciated, the hex-shaped detent46prevents the bolt40from rotating about its central axis, and thereby minimizes the potential for the bolt40to loosen or disengage the bore42as the lever14rotates about the bolt40during use. Additionally, a lock washer or a polymer-insert lock nut may be used to further secure the bolt40in the bore42.

An upper arm80extends generally upward and rearward from the upper end of the trunk74just below the upper circular bore72. The arm80is shaped to resemble a human arm with an upward-directed “elbow” such that the lever14resembles a stylized human sitting in and leaning forward in a wheelchair. The arm80is shaped to cradle in the inverted “V” cross-channel24formed in the underside of the central element20of the body12when the lever14is rotated to its most rearward position about the bolt40.

The lever14also has a third lateral and horizontal through bore82, positioned in the trunk74just below the upper circular bore72. The bore82is shaped and sized to loosely receive a metal tube84there through, such that the metal tube84is able to freely rotate about is longitudinal axis when positioned in the bore82. The metal tube84is approximately 1¼ inches long, and therefore when centrally positioned in the bore82extends approximately 7/16 inch beyond each end of the bore82. Each end of the tube84fits into a bore86at one end of one of a matching bookend pair of short polymer or aluminum cable links88. Each link88is approximately ¾ inch long, ¼ inch wide and ¼ inch thick, with rounded ends and a circular cable nipple slot90that is positioned in the end opposite the bore86and which runs parallel to the bore86. The cable links88are secured to the trunk74of the lever14by metal machine screws92that thread into the ends of the tube84. The tube84and bores86are sized to allow the links88to freely rotate about the tube84when secured by the screws92to the trunk74of the lever14.

Referring now toFIGS. 1 and 5, it can be seen that the lever assembly10is designed to attach directly to one end of a pair of Bowden cables100, where each cable100extends from the lever14to one of two representative wheel lock assemblies102that are positioned near the rear wheels of the wheelchair. Each of the cables100terminates in one of the two clamp bores formed by the grooves54and58in the rear element22of the lever assembly10, where the end of the cable100is rigidly secured. A cable wire103extends from the end of the cable100and attaches to a nipple104which is releasably positioned in one of the two nipple slots90of one of the two cable links88. At the other end, each cable terminates and is attached to one of the two wheel lock assemblies102.

Referring toFIG. 5, each representative wheel lock assembly102comprises a tubular spring-loaded actuator104, a lock-pin106housed in the actuator104, and a lock ring108attached to the wheelchair wheel proximate the actuator104. The actuator104is rigidly attached to the frame of the wheelchair proximate and longitudinally facing its respective lock ring108attached to one of the two wheelchair wheels. The lock ring108comprises a set of detents or bores110that are configured to receive and mate with the tip of the lock-pin106. The lock-pin106retractably protrudes from the end of the actuator104that faces the wheel. A spring (not shown) housed inside the actuator104exerts sufficient longitudinal spring tension on the lock-pin106to hold the lock-pin106in a position extended partially out of the actuator104in which the tip of the lock-pin106engages one of the detents110in the lock ring108. Thus, when extended into one of the detents110, the lock-pin106locks the lock ring108and thereby locks the wheelchair wheel to prevent the wheel from rotation about its axle. When sufficient longitudinal force, directed away from the lock ring108, is applied to the lock-pin106to pull it back (i.e., retract) into the body of the actuator104, the lock-pin106disengages from its engagement with the detents110in the lock ring108, and thereby unlocks the wheel and allows the wheel to turn freely about its axle.

Consequently, as can be appreciated by one of ordinary skill in the art, pushing or pulling the lever14forward so as to pivot the lever14in a forward manner about the bolt40, simultaneously pulls both inner wires103of each the cables100forward, and in a direction away from their respective actuators104. This provides provide sufficient longitudinal force on the wires103to overcome the spring tension in the actuators104and pull their respective lock-pins106out of engagement from their corresponding detents110so as to disengage the wheel locks for both wheel lock assemblies102.

Likewise, pushing (or allowing the springs in the actuators104) to move the lever14backward so as to pivot the lever14rearward about the bolt40, allows the wires103in both cables100to simultaneously relax and thereby allows the springs in both actuators104to urge the spring-loaded lock-pins106toward engagement with their respective wheel locks for both wheel lock assemblies102.

As one of ordinary skill in the art will further recognize, the lever assembly10can be used in the same manner as described in the previous two paragraphs when the lever assembly10is attached to different wheel-lock assembly configurations, such as for example, the Ebersole design, such as shown by way of example inFIG. 8.

Applicant's novel design and configuration contrasts sharply with preexisting or traditional wheel lock lever assemblies. This includes the Ebersole Design, such as is depicted inFIGS. 7 and 8, in which the lever attaches to a single Bowden cable. The single Bowden cable thereafter engages a cable splitter, from which two separate cables extend, one attaching to each of the two wheel lock assemblies that are positioned near the rear wheels of a wheelchair.

In addition, referring toFIGS. 1, 2 and 5, it will be understood that the lower plate56acts as a clamp when attached to the underside of the rear element22to firmly and immovably secure each of the cables100to the lever assembly body12. This contrasts sharply with the traditional wheel lock lever assemblies including the Ebersole Design, such as is depicted inFIGS. 7 and 8, in which the single Bowden cable is not clamped to the lever assembly, but rather “floats” in a cavity to house the end of the cable.

Further, it will be understood that the grip70has a shape that allows the wheelchair occupant to manipulate the lever even when the occupant has limited use of his/her arms and/or hands and/or one or more digits. That is, in sharp contrast to the simple “arm” of preexisting or traditional wheel lock lever assemblies including the Ebersole Design, such as is depicted inFIGS. 7 and 8, a user with such a disability can readily manipulate the lever14of the present design in a multitude of ways, such as for example, placing one or more digits in the ring of the grip70, grasping the most convenient edge of the grip70, or simply by pushing or pulling the grip70. Also, the shape of the grip70allows the user to push or pull the lever14by placing his/her hand in the “ring” of the grip70, without having to reposition that hand. That is, the Ebersole Design, as well as any other designs of similar configuration, provide no more than a straight arm or an arm with a simple, shallow elbow for grasping or gripping shape the arm, which can be difficult to the physically impaired to reliably operate. Further, the Ebersole design requires the user to reposition the hand between alternate sides of the lever when alternating between pushing or pulling of the Ebersole lever.

While I have described in the detailed description a configuration that may be encompassed within the disclosed embodiments of this invention, numerous other alternative configurations, that would now be apparent to one of ordinary skill in the art, may be designed and constructed within the bounds of my invention as set forth in the claims. Moreover, the above-described novel lever assembly10of the present invention can be arranged in a number of other and related varieties of configurations without expanding beyond the scope of our invention as set forth in the claims.

For example, the lever assembly10is not limited to use with specifically two cables100, but rather can be configured and used in conjunction with one or more than two cables100. Further, the lever assembly10does not necessarily require that the lever14have the shape or configuration as depicted. That is, the lever14can be alternative constructed, for example, without the grip70or the arm80, or can be constructed with similar features of varying shapes and sizes. For example, the grip70can alternately be constructed in an elliptical or an irregular shape, have a smaller or larger opening, or could comprise a slot instead of a closed ring. That is, the grip70can have a variety of configurations so long as the grip70provides two inner contact points such that the wheelchair occupant is able to push or pull the on the lever14without repositioning the occupant's hand. For example, the legs71aand71bneed not be conjoined, and can be constructed in a variety of configurations, so long as the shape allows the wheelchair occupant to position one or more digits between the legs71aand71b,such that the occupant need not reposition that hand to alternate between pushing or pulling the lever14with the grip70. Also, the lever14also need not be uniformly flat, as depicted, but instead could be constructed or formed with varying widths or thicknesses, so long as the lever14is able to perform the functions outlined in this disclosure. In addition, the lever14need not necessarily rotate about an axis in order extend or relax the cables100. Rather, the lever14could be designed to slide or otherwise shift from one position to another to facilitate the lever functions disclosed herein.

Similarly, the body12can have a wide range of shapes and sizes, so long as the body is able to attach to a wheelchair, provides a location to attach the cables100. For example, the rear element22can configured in a wide range of shapes and sizes, and can be positioned at various orientations on the body12, so long as the element is capable of securing the cables100to the body12in a manner to allow the lever to properly pull and release the cables100as disclosed herein.

Further, the body12can be configured to attach to the wheelchair in many different manners and at various different locations on the wheelchair, not just with the single tube strap16, so long as the body12is securely fastened to the wheelchair to allow the lever assembly10to operate as described in this disclosure. That is, the body12could be configured, for example, to attach with several tube straps to a vertical frame tube instead of a horizontal frame tube. Similarly, the body12could be configured to use screws, pins or other attachment devices and/or mechanisms to secure the lever assembly10to the wheelchair.

In addition, the wires in the cables100need not necessarily be attached to the lever14with the cable links88as shown. Rather, the wires in the cables100can be attached to the lever14in other ways, including for example, positioning the nipple slots90directly on the lever14, clamping the wires in the cables100to the cable links88or directly to the lever14, or other similar means.

Additional variations or modifications to the configuration of the above-described novel lever assembly10of the present invention may occur to those skilled in the art upon reviewing the subject matter of this invention. Such variations, if within the spirit of this disclosure, are intended to be encompassed within the scope of this invention. The description of the embodiments as set forth herein, and as shown in the drawings, is provided for illustrative purposes only and, unless otherwise expressly set forth, is not intended to limit the scope of the claims, which set forth the metes and bounds of our invention.