Wheelchair propulsion assist device

Abstract

A propulsion assist device for a wheelchair having a hand rim slideably housed inside a channel of a frame pivotably connected to a lever arm. The frame is further comprised of a portion of grip material positioned inside the channel along an underside of a top of the frame. When a pair of devices are installed on a pair of hand rims of the wheelchair, the wheelchair is moved forward by a coordinated rowing motion of both lever arms forwards and then backwards along the hand rim. The pivoting motion of the frame causes the grip material sandwiched between the frame and the hand rim to pressure grip the hand rim and turn it when a user moves the lever arms through their rowing motion. Repositioning the frame along the hand rim causes the gripping material to release and slide along the hand rim before repositioning.

Claims

1. A propulsion assist device for a wheelchair having a manual hand rim affixed to a drive wheel, the propulsion assist device comprising: a lever arm having an upper end and a lower end; a lower aperture formed into the lower end of the lever arm; a frame having a top affixed to a pair of opposed side walls in spaced apart relationship, an underside of the top and the spaced apart relationship of the side walls defining a channel having a rim opening sized and shaped to receive the manual hand rim of the wheelchair and allow the manual hand rim to rotate therein, and a lowermost channel opening perpendicular to the rim opening and opposite the underside of the top; a bottom lip formed on at least one side wall of the pair of opposed side walls and oriented so as to constrict the channel opening to secure the manual hand rim within the channel; a grip material positioned on the underside of the top inside the channel; a flange extending from the top of the frame, the flange formed with a flange hole; and a lower fastener sized and shaped to couple the lower end of the lever arm to the flange through the flange hole and the lower aperture; wherein the lower fastener pivotably couples the lever arm to the flange.

2. The propulsion assist device in claim 1, further comprising a handle sized and shaped to be gripped by a human hand affixed to the upper end of the lever arm.

3. The propulsion assist device in claim 1, wherein the lever arm is further comprised of a telescopically adjustable upper arm and a lower arm, whereby a length of the lever arm is adjustable.

4. The propulsion assist device in claim 1, wherein each of the side walls is formed with a bottom lip in spaced apart relationship with one another so as to create a gap between the bottom lips.

5. The propulsion assist device in claim 1, wherein the lower end of the lever arm having the lower aperture is a flange.

6. The propulsion assist device in claim 1, wherein the top is further comprised of a frame aperture and at least one side wall is further comprised of a hole aligned with the frame aperture, the frame aperture and the hole sized and shaped to receive a frame fastener, removably coupling the top to the at least one side wall.

7. The propulsion assist device in claim 1, further comprising a replacement rim having a flattened profile adapted to replace an original manufacturer hand rim of the wheelchair using existing fasteners of the original manufacturer hand rim.

8. The propulsion assist device in claim 7, wherein the channel is sized and shaped to receive the replacement rim.

9. A propulsion assist kit for a manual wheelchair having a hand rim, the kit comprising: a lever arm having an upper handle end and a lower flange; and a c-shaped frame pivotably affixed to the lower flange; wherein the c-shaped frame is further comprised of a channel having a rim opening and a channel opening, the channel sized and shaped to receive the hand rim through the channel opening and the hand rim rotates within the rim opening; and wherein the c-shaped frame is further comprised of a removable side wall having a bottom lip oriented so as to constrict the channel opening, securing the hand rim within the channel.

10. The propulsion assist kit in claim 9, further comprising a replacement rim having a flattened rim profile and adapted to replace the hand rim of the wheelchair by using a same set of fasteners as the hand rim of the wheelchair.

11. The propulsion assist kit in claim 10, wherein the c-shaped frame is further comprised of a lower gap sized and shaped to receive the replacement rim, whereby the c-shaped frame can be installed onto the replacement rim without tools.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of the invention will become apparent from a consideration of the subsequent detailed description presented in connection with accompanying drawings, in which:

(2) FIG. 1 is a perspective view of a wheelchair propulsion assist device according to the invention, shown installed on a manual wheelchair.

(3) FIG. 2 is a perspective detail view of the wheelchair propulsion assist device in FIG. 1.

(4) FIG. 3 is a top view of the wheelchair propulsion assist device in FIG. 1, shown with a lever arm extended in a forward facing direction.

(5) FIG. 4 is an exploded view of the wheelchair propulsion assist device according to the invention, shown with an optional hand rim.

(6) FIG. 5 is a side elevation detail view of the wheelchair propulsion assist device in FIG. 1.

(7) FIG. 6 is a back perspective view of the wheelchair propulsion assist device in FIG. 1.

(8) FIG. 7 is a bottom view perspective view of the wheelchair propulsion assist device in FIG. 1, showing an underside of the hand rim inside a channel.

(9) FIG. 8 is a partial back view of the rim in FIG. 1.

(10) FIG. 9 is a detail back view of a lower portion of the lever arm and a frame of the wheelchair propulsion assist device.

(11) FIG. 10 is a top view of the lower portion of the lever arm and the frame of the wheelchair propulsion assist device.

(12) FIG. 11 is a detailed perspective view of the lower portion of the lever arm and frame of the wheelchair propulsion assist device.

(13) FIG. 12A is a back perspective view of the wheelchair propulsion assist device installed on a manual wheelchair, shown with a user positioning the lever arm in start position for forward propulsion.

(14) FIG. 12B shows the user in FIG. 12A with his arms extended and the lever arms moved away from the user's body.

(15) FIG. 12C shows the user in FIG. 12B repositioning his arms to the start position. The pressure from the user's hands on the lever arms push the frames against the hand rims thus turns the hand rims counterclockwise, propelling the wheelchair forward.

(16) FIG. 13 is a perspective view of a prior art manual wheelchair.

DRAWINGS LIST OF REFERENCE NUMERALS

(17) The following is a list of reference labels used in the drawings to label components of different embodiments of the invention, and the names of the indicated components. 100 wheelchair propulsion assist device or assist 10 handle12 lever arm or arm 12a upper arm 12b adjustable fastener 12c adjustment hole 12d arm hole 12e lower arm 14 upper aperture 14a upper fastener 14b upper nut 16 lower aperture 16a lower fastener 16b lower nut 18 top flange 18a flange hole or hole 20 frame 22 top 22a frame fasteners 22b frame apertures 24 side wall 24a bottom lip 24b gap 26 channel 26a channel top wall or underside of top 28 rubber liner or grip material 30 replacement hand rim 40 wheelchair 42 OEM hand rim 44 drive wheel 46 wheelchair user or user 48 arm rest

DETAILED DESCRIPTION

(18) A manual wheelchair propulsion assist device or assist according to the invention 100 is shown in FIGS. 1-12C, with FIG. 13 showing a prior art folding wheelchair 40 with an original equipment manufacturer (OEM) hand rim 42. Turning now to the Figures, the assist 100 is comprised of a lever arm 12 with an adjustable length telescoping upper arm 12a portion and a lower arm 12e. The upper arm 12a formed with a plurality of adjustment holes 12c and is connected to the lower arm 12e by positioning an adjustable fastener 12b through an uppermost arm hole 12d in the lower arm 12e and through one of the plurality of adjustment holes 12c in the upper arm 12a. The lower arm 12e and upper arm 12a are adjusted according to a user's 46 perceived comfort. In other embodiments, the arm 12 is of a fixed length and non-adjustable, but offered with arms of varying length to allow the user 46 to pick an appropriate arm length as desired. An upper aperture 14 is formed into the upper arm 12a, and a handle 10 is secured thereto with an upper fastener 14a and upper nut 14b. A lower aperture 16 sized and shaped to receive a lower fastener 16a is formed at a lowermost end of the lever arm 12, in the Figures shown as a lower arm 12e and secured thereto by the lower fastener 16a and a lower nut 16b. The lower arm 12e and upper arm 12a shown in the Figures have U-shaped bodies, but could also have a square or other shape, with the lower aperture 16 formed as a single through hole or a pair of aligned holes receiving the lower fastener 16a, and a cutaway portion or flange formed at the lowermost end to allow space for the lever arm 12 to pivot forwards and backwards about the lower fastener 16a.

(19) A frame 20 has a top 22, and a pair of side walls 24 affixed to the top 22, the side walls 24 sized and shaped to mirror one other. In the Figures, each side wall 24 is further formed with a receiving aperture aligned with a corresponding frame aperture 22b to allow the top 22 to be removably affixed to the side walls 24 via the frame fasteners 22a. The top 22 is formed with an upright or top flange 18, the top flange 18 formed with a flange hole or hole 18a. The lower aperture 16 of the lower arm 12e is aligned with the hole 18a and the lower fastener 16a couples the top flange 18 to the lower arm 12e. The top flange 18 and the lever arm 12 are in hingeable relationship, where the lever 12 at its lowermost end can rock forwards and backwards about the lower fastener 16b and in relation to the top flange 18 and where moving the lever arm 12 also moves the frame 20 forwards or backwards along a hand rim 30.

(20) Each side wall 24 has a bottom lip 24a, where the side walls 24 and the underside of the top 26a define an interior channel 26. In the embodiment shown in the Figures, the channel 26 is sized and shaped to receive the hand rim 30, as shown in FIG. 7, and the inventor notes that the hand rim 30 is shown with an approximately rectangular cross section about 22 inches wide, and the channel 26 thus mimics a same cross section and width, but with a larger overall height as compared to the hand rim 30 to allow the underside of the top 26a on a front facing side of the frame 20 to tilt forwards and backwards. In the embodiment shown in the Figures, the channel 26 has approximately 0.5 to 1 inch of clearance from the hand rim 30 contained therein. The channel 26 can also complement a shape of the OEM hand rim 42 shown in FIG. 13, which has an approximately circular cross section, again with some headroom between the underside of the top 26a and the OEM hand rim 42. Hence, while the assist 100 in the Figures is shown with the hand rim 30 in fact replacing the OEM hand rim 42 shown in FIG. 13, the frame 20 in other embodiments can be configured to be used with the existing OEM hand rim 42 by modifying a shape of the channel 26.

(21) A gap 24b separates the bottom lip 24a of each side wall 24 and in FIG. 7, the gap 24b is shown with a rear end of the gap 24b flaring outwardly towards an outermost perimeter of the frame 20, the flaring rear end of the gap being wider relative to a front end of the gap 24b positioned towards a front of a wheelchair 40. The top 22 is shown in the Figures as being formed with four frame apertures 22b removably secured to the side walls 24 by four frame fasteners 22a, however the inventor notes that the frame 20 side wall and top configuration need only be such that the frame 20 is removably positionable onto the hand rim 30. The inventor notes that all the fasteners 14a 16a 22a shown in the Figures are threaded fasteners requiring simple tools such as a screwdriver and wrench in order to install or remove the assist 100 from the wheelchair 40, however, all the fasteners, including those for the hand rim 30 can also be configured as thumb screws, allowing the assist 100 to be installed or removed without tools. Thus, the frame 20 can be configured in many ways other than what is shown in the representative embodiment in the Figures.

(22) Finally, a piece of rubber or grip material 28 or other similarly durable material with gripping capability, is affixed to the underside of the top 26a, facing the channel 26 and is typically a same length or longer length than the channel 26.

(23) To install the assist 100 shown in the Figures, the handle 10, lever arm 12, top 22 and one side wall 24 are preassembled, with the remaining side wall 24 and frame fasteners 22a to be secured. The lever arm 12 length is adjusted by telescoping the upper arm 12a to a desired length and inserting the adjustable fastener 12b into the adjustment hole 12c and through the arm hole 12d. The OEM hand rim 42 is removed and the hand rim 30 is secured to each drive wheel 44 of the wheelchair 40 using existing fasteners of the OEM hand rim 42. The partially assembled frame 20 is positioned onto the hand rim 30. The remaining side wall 24 is then secured to the top 22 by coupling the frame fasteners 22a into the frame apertures 22b. The hand rim 30 is thus now positioned inside the channel 26 of the frame 20. Alternatively, for a frame 20 that is a single piece, the hand rim 30 is slipped into the channel 26 via the gap 24b and then rotated to position the top flange 18 and lever arm 12 upwards. The gap 24b provides a convenient method by which to install/uninstall the assist 100 without the need for tools and allows debris or moisture that might otherwise collect to be removed from the channel 26.

(24) Turning to FIGS. 12A-C, to use the assist 100, a wheelchair user or user 46 grasps the handles 10 and bends his or her elbows, putting the lever arm 12 in a neutral or start position. The start position is one in which the user 46 positions the frame 20 in a desired location and the user 26 can choose to maneuver both lever arms 12 at the same time or each one individually, in the case where the user 46 wants to turn the wheelchair 40 into a different direction. Once the frame 20 is positioned into the desired start location, the user 46 applies downwards force on the lever arms 12, which causes the frame 20 to push downwards, and thus pressing the grip material 28 against the rim 30. The frame 20 is able to tilt forwards and backwards when installed on the rim 30, and thus the start position chosen by the user 46 may cause the frame 20 to tilt forward or backwards, but with the grip material 28 compressed between the underside of the top 26a and the rim 30. As the user 46 straightens his or her arms, the rims 30 turn along with the drive wheels 44 to which they are attached, causing the wheelchair 40 to move forward. To move backwards, the user's start position is with arms extended and pressure exerted against the rim 30. The user 46 bends his or her elbows again and relaxes the downward pressure on the lever arms 12, causing the frame 20 to slide backwards on the rim 30 and resume the start position and thus releasing the hand rim 30 from the grip material 28. The frame 20 is repositioned and the user 46 again extends his or her arms to move the drive wheels 44. If the user 46 wants to turn right, the user 46 engages a left side lever arm to turn a left side drive wheel to an appropriate position. To move backwards, the user 46 positions the frame 20 in a desired location on the hand rim 30, and instead tilts the frame 20 such that a read end of the frame 20 compresses the grip material 28 against the hand rim 30 to move the drive wheels in a backwards direction.

(25) The inventor's assist 100 has many advantages over the prior art. It is comprised of few parts and is easily installed and uninstalled, as desired. This design is economical to manufacture and maintain. The components are all made of metal in the embodiment shown, however are lightweight and thus do not add any significant extra weight to the wheelchair that would further burden the user 46. In the embodiment using the existing OEM hand rim 42, removal of the assist 100 allows the user 46 the full option of propelling the wheelchair using existing means. The inventor notes that his hand rim 30 can also be used without the assist 100 to hand propel the wheelchair 40 and his hand rim 30 design maximizes the surface area by which the hand rim 30 contacts the underside of the top 26a for maximum propulsion of the drive wheels 44. In the case of the OEM hand rim 42, the channel 26 is most optimally configured with an elongated cross section to minimize lateral shifting of the OEM hand rim 42 inside the channel 26, which also optimizes the compression force of the frame 20 against the OEM hand rim 42 to propel the drive wheels 44. For the hand rim 30 shown in the embodiment in the Figures, side to side movement of the hand rim 30 within the chamber 26 is less critical given the flattened cross section of the hand rim 30, and thus less exacting machining is required for the frame 20, reducing manufacturing complexity and cost. The inventor believes his assist 100, sold as a kit with or without the hand rim 30, is ideal for retrofitting existing wheelchairs, and provides sufficient mechanical leverage allowing the most feeble-strength user 46 to nevertheless propel the wheelchair 40 easily and independently.

(26) It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the scope of the present invention. For instance, the lever arms 12 are currently shown as having a standard length, but they could easily be configured to be telescoping or otherwise adjustable to accommodate different body sizes, etc. With the exception of the grip material 28, the lever arms 12, handles 10 and the frame 20, currently shown in the Figures as being made of metal, can also be made of any durable material including structural plastic, or a combination of materials could be used together for the assist 100 to minimize weight, decrease cost, etc. as desired. The inventor notes that his assist 100 is lightweight, easy to use and install and requires limited tools and learning time to use. He believes his simple, elegant solution is both cost effective and ergonomic, allowing anyone of any income level a simple and useful way to manually propel an existing wheelchair. In particular, the assist 100 permits the user to have a tight turning radius to redirect the wheelchair 40 as desired, something that current assist devices and electric chairs currently cannot perform. As the assist 100 is completely manual in nature, the user 46 has complete control over the movement, direction and speed of the wheelchair, and additionally, the frame 20 can also be used for supplemental braking or maintenance of position on hills, or other non-level surfaces. The inventor notes too that the hinging relationship between the lever arm 12 and the frame 20 can be configured in many other ways, and the only criticality in any new arrangement is that the frame 20 maintain its ability to clamp onto the hand rim 30 or OEM hand rim 42 and then lift off when the lever arm position is adjusted. The tilting action of the frame 20 is not the only way this engagement/disengagement of the frame to the hand rim can be performed, and the inventor notes there are other ways this can still be implemented and not change the overall function of the assist 100.