ADJUSTABLE WHEELCHAIR HANDRIM WITH MOVABLE FRICTION BAND

Abstract

An adjustable manual wheelchair handrim with a moveable elastomeric friction band. The position of the tubular handrim can be moved to a desired location relative to the wheel rim depending on the needs and limits of the user. The movable friction band is stretched around the drive surface of the handrim at a desired location preventing it from moving and providing increased frictional properties when gripped by the user during pushes. The friction band can be permanently affixed at a location to further prevent movement and slippage between the handrim and the friction band.

Claims

1. A handrim for the wheel of a manual wheelchair, comprising: a tubular handrim; and a movable elastomeric friction band.

2. The handrim of claim 1, wherein the handrim comprises an ergonomic tubular shape that profiles the hand when gripped.

3. The handrim of claim 1, wherein the handrim further comprises a drive surface that extends from the top of the handrim and wholly or partially spans the gap between the handrim and the wheel rim of a wheelchair wheel when mounted.

4. The handrim of claim 3, wherein the drive surface extends around the periphery of the entire handrim.

5. The handrim of claim 1, further comprising a plurality of rigid attachment tabs that extrude from a terminating end of the drive surface.

6. The handrim of claim 5, said rigid attachment tabs comprising elliptical or circular slots, adapted to receive fasteners to mount the handrim to a wheelchair wheel rim.

7. The handrim of claim 1, wherein the friction band is stretched over the handrim and only held in place by the elasticity of the band.

8. The handrim of claim 1, wherein the friction band is permanently affixed to the handrim.

9. The handrim of claim 3, where the offset distance of the handrim from the wheel rim is adjustable.

10. A handrim for the wheel of a manual wheelchair, comprising: a handrim, wherein the handrim has an ergonomic tubular shape that profiles the hand when gripped.

11. The handrim of claim 10, further comprising a drive surface that extends from the top of the tubular handrim and wholly or partially spans the gap between the handrim and the wheel rim of a wheelchair wheel when mounted.

12. The handrim of claim 11, wherein the drive surface extends around the periphery of the entire handrim.

13. The handrim of claim 10, further comprising a plurality of attachment tabs that extrude from one end of the drive surface.

14. The handrim of claim 13, wherein the attachment tabs have slots adapted to receive fasteners to mount the handrim to a wheelchair wheel rim.

15. The handrim of claim 14, wherein the offset distance of the handrim from the wheel rim is adjustable by moving the position of the attachment tabs laterally relative to the wheel rim.

16. The handrim of claim 10, further comprising an elastomeric friction band.

17. An adjustable handrim for the wheel of a manual wheelchair, comprising: a tubular handrim; a drive surface that extends from the top of the tubular handrim and wholly or partially spans the gap between the handrim and the wheel rim of a wheelchair wheel when mounted; and a plurality of attachment tabs that extrude from one end of the drive surface, wherein the attachment tabs have slots adapted to receive fasteners to mount the handrim to the wheel rim, wherein the offset distance of the handrim from the wheel rim is adjustable by moving the position of the attachment tabs laterally relative to the wheel rim.

18. The handrim of claim 17, wherein the handrim comprises an ergonomic tubular shape that profiles the hand when gripped.

19. The handrim of claim 17, further comprising an elastomeric friction band stretched over the handrim and drive surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a perspective sectional view of an adjustable wheelchair handrim with a movable friction band attached to a typical wheelchair wheel in accordance with an exemplary embodiment of the present invention.

[0020] FIG. 2 shows a cross-sectional view of the wheel rim, the tire, and the adjustable wheelchair handrim with a movable friction band positioned as close to the wheel as possible.

[0021] FIG. 3A shows a cross-sectional view of the handrim adjusted to a position with minimum offset, displaying its range of adjustability relative to the wheel.

[0022] FIG. 3B shows a cross-sectional view of the handrim adjusted to a position with medium offset.

[0023] FIG. 3C shows a cross-section view of the handrim adjusted to a position with maximum offset.

[0024] FIG. 4 shows a cross-sectional view of a larger elastomeric friction band with a greater depth.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0025] In one exemplary embodiment, as shown in FIG. 1, the present invention comprises an adjustable wheelchair handrim with movable friction band 10 that a wheelchair user can use to propel their manual wheelchair. The adjustable wheelchair handrim with movable friction band 10 mounts to a standard wheelchair wheel rim 14 that is subsequently connected to the tire 12. The assembly of the aforementioned parts, with additional spokes 18 and a wheel hub 20, comprise a typical manual wheelchair wheel 16, where the user can grip and apply a torque to the handrim causing rotation of the wheel assembly.

[0026] The adjustable wheelchair handrim with movable friction band 10 is comprised of an ergonomic tubular handrim 22 which transforms directly into a drive surface 24, as can be seen in FIG. 2. The ergonomic tubular handrim 22 contains a profile that matches the shape of the hand and is sized to this manner. The drive surface 24 continuously extends from the top surface of the ergonomic tubular handrim 22, spanning the offset from the ergonomic tubular handrim 22 and the wheel rim 14. This presents an addition surface for the thumb and palm of the user to contact when gripping, while providing protection for the fingers from jamming into the spokes 18 or rigid attachment tabs 26 as the wheel rotates. The combination of the ergonomic tubular handrim 22 and the drive surface 24 provide maximum surface area for the hand of the user to grip when grabbing the handrim and performing a push.

[0027] A plurality of the aforementioned rigid attachment tabs 26 extrude or extend from the terminal end of the drive surface 24. Individual rigid attachment tabs 26 angle inward before bending horizontal, providing a level top surface 28 to mate with the inner-flat surface of the wheel rim 14. The tabs have elongated circle slots 30 through which fasteners 32 can be used to affix the handrim to the wheel rim 14. The handrim, comprising the ergonomic tubular handrim 22, drive surface 24, and rigid attachment tabs 26, is made of a metal material for durability and rigidity.

[0028] As shown in FIG. 1 and FIG. 2, an elastomeric friction band 34 stretches around the handrim and rests on the drive surface 24 and ergonomic tubular handrim 22. The aforementioned elastomeric friction band 34 possesses increased frictional properties as compared to the metal handrim. This reduces the amount of gripping needed by the user during a push and decreasing slipping between the hand and handrim. The combination of reduced gripping and slippage increases the efficiency of the user during propulsion. The user is also able to use the ergonomic tubular handrim 22 and bottom of drive surface 24 for breaking without burning or causing damage to the hand.

[0029] The elastomeric friction band 34 is held in place when the user is not gripping the handrim by the elastic properties of the band material, and the tendency of the band to contract to its undeformed dimension when stretched. The band resists circumferential movement relative to the handrim during a push through the friction between the bottom surface of the band 36 and the top surfaces of the drive surface 24 and ergonomic tubular handrim 22. The downward force of the user's hand also contributes to prevent movement.

[0030] Furthermore, the elongated circle slots 30 allow adjustability of the position of the ergonomic tubular handrim 22 relative to the wheel rim 14 and tire 12. As seen in FIGS. 3A-C, this gives the distance h needed to grip the tire and handrim a range. The offset distance can be minimized by moving the handrim inward until the drive surface 24 or rigid attachment tabs 26 contact the wheel rim 14. The offset distance can be maximized by moving the handrim outward until the outermost surface of the attachment tab slot 38 makes contact with the fastener 32. This range of adjustability presents a variable distance between the ergonomic tubular handrim 22 and the wheel rim 14 and tire 12 in addition to a variable amount of handrim surface area not in contact with the elastomeric friction band b to be used for breaking.

[0031] In another embodiment, because the elastomeric friction band 34 is held in place by its elastic deformation and is not permanently affixed to the handrim, it can be moved outward perpendicular to the plane of the wheel. When moved, more of the band rests on the ergonomic tubular handrim 22 in order to provide higher friction in a different location on the handrim. The movability of the elastomeric friction band 34 allows individual users to position the increased frictional properties in the location that is most advantageous. This movability, coupled with the adjustable offset distance, provides the user with flexibility and allows them to customize their handrim to maximize their propulsion efficiency.

[0032] Further, due to the mobility of the elastomeric friction band 34, it can be removed from the handrim. In this exemplary embodiment, the user is presented with a metal handrim with an adjustable offset distance between the ergonomic tubular handrim 22 and the wheel. Even without any added frictional properties, this embodiment still improves efficiency by providing greater contact surface area for gripping.

[0033] In other embodiments, the position of the handrim relative to the wheel rim 14 and tire 12 can be adjusted to any desired location, thus varying the offset distance. In yet other embodiments, the position of the elastomeric friction band relative to the wheel rim 14 and handrim can be adjusted to any desired location. FIG. 4 illustrates an embodiment where a large elastomeric friction band 38 with a greater depth 40 than the depth 36 of the elastomeric friction band 34 shown in FIGS. 3A-C is used to provide more surface area of increased friction. This kind of band is advantageous to a user with limited gripping ability and that mostly relies on applying a downward force to the top surface of the handrim in order to induce rotation of the wheel.

[0034] The contour of the elastomeric band can be changed in order to provide the best configuration for each individual wheelchair user. Also, the position of the band, regardless of its profile, can be permanently affixed to the handrim if the configuration is found to be ideal and permanence of band location is advantageous. The method of mounting can be by chemical adhesives, rigid fasteners, or any other means.

[0035] Thus, it should be understood that the embodiments and examples described herein have been chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited for particular uses contemplated. Even though specific embodiments of this invention have been described, they are not to be taken as exhaustive. There are several variations that will be apparent to those skilled in the art.