WO2004034944A2

WO2004034944A2 - Footrest apparatus for a wheel chair and method of adjusting the same

Info

Publication number: WO2004034944A2
Application number: PCT/US2003/033136
Authority: WO
Inventors: Joseph W. Adams
Original assignee: Invacare Corporation
Priority date: 2002-10-17
Filing date: 2003-10-17
Publication date: 2004-04-29
Also published as: AU2003284280A1; WO2004034944A3; AU2003284280A8; US20040075327A1

Abstract

Footrest apparatus for use on a wheel chair comprises: a footrest shaft comprising two tubular members (10, 12) coaxially aligned to accommodate a sliding of one of the two tubular members within the other for length adjustment of the shaft. One end of the footrest shaft is attachable to a structure of the wheel chair and a footrest plate (14) is attachable to the footrest shaft at the other end. A plurality of inline, spaced apart, diametrically opposed pairs of apertures (40) are provided along the sides of the other tubular shaft member. The one tubular shaft member includes a pair of diametrically opposed spring loaded pins (44) which retract into and protrude through apertures (46) at the outer surface thereof, the pins being aligned with the diametrically opposed aperture pairs of the other shaft member. Accordingly, when the one tubular shaft member slides within the other tubular shaft member for length adjustment of the shaft, the pins retract during sliding and spring out and lock into a selected pair of apertures of the other member at a desired shaft length. The footrest apparatus may include a cam clamp (50) attachable to the periphery of the other shaft member. The cam clamp includes a lever (52) operative in a first position to secure the other shaft member to the one shaft member at the desired shaft length and operative in a second position to release the other shaft member from the one shaft member for shaft adjustment. A method of adjusting the footrest apparatus of the wheel chair is further disclosed.

Description

FOOTREST APPARATUS FOR A WHEEL CHAIR AND METHOD OF ADJUSTING THE SAME

BACKGROUND OF THE INVENTION

[0001] The present invention is directed to wheel chair apparatus, in general, and more particularly, to a footrest apparatus for a wheel chair and method of adjusting the same. [0002] Wheel chairs come in all shapes and forms, and most include apparatus for supporting the user's feet above the floor which is commonly referred to as a footrest. Some wheel chairs include a U-shaped unitary footrest attachable to the front legs of the chair, for example, for supporting both feet of the user. Others include individual left and right footrest apparatus, each attachable to a left and right front leg of the chair, respectively. In each case, the footrest apparatus includes a footrest plate at the bottom for supporting the foot or feet of the user and may include a calf pad for support of the user's leg as well. Consequently, the footrest apparatus requires some form of mechanical adjustment to accommodate the leg length of the user. This adjustment is generally accomplished through upper and lower telescoping shaft members and a clamping mechanism to secure the shaft members at the adjusted length of the user. In general, this mechanical adjustment operation requires tooling, like a screw driver and wrench, for example. In addition, this mechanical length adjustment mechanism suffers from wear over time and may require frequent adjustment. [0003] The individual footrest assemblies generally include some form of mechanical latching and unlatching mechanism at a location where the upper shaft member of the footrest assembly attaches to the leg of the chair. This mechanism permits the footrest assembly to be latched in place when in use and unlatched and swung to an out-of-the-way position when not used by the user. However when latched in place for use, only the upper shaft member is latched in place by the latching mechanism and the lower shaft member is secured to the upper shaft member at the adjusted length by the clamping mechanism. During use, the wheel chair may be maneuvered through corridors, hallways and doorways which are sometimes a tight fit causing the footrest plate to collide at times with a surface. These collisions or jolts may cause a rotation of the lower shaft member about the locked upper shaft member rendering the footrest plate to be disoriented and uncomfortable to the user. In these situations, tooling is again required to readjust the upper and lower shaft members to the proper orientation for the user. [0004] The present invention avoids the above described drawbacks of the current footrest apparatus and provides for tool free length adjustment with a securing mechanism to eliminate movement due to wear and lower/upper shaft member rotation as a result of footrest plate collisions during use.

SUMMARY OF THE INVENTION

[0005] In accordance with one aspect of the present invention, footrest apparatus for use on a wheel chair comprises: a footrest shaft comprising two tubular members coaxially aligned to accommodate a sliding of one of the two tubular members within the other for length adjustment of the shaft, the footrest shaft being attachable to a structure of the wheel chair at one end; a footrest plate attachable to the footrest shaft at the other end; the other of the two tubular shaft members having a plurality of inline, spaced apart, diametrically opposed pairs of apertures along the sides thereof; and the one of the two tubular shaft members having a pair of diametrically opposed spring loaded pins which retract into and protrude through apertures at the outer surface thereof, the pins being aligned with the diametrically opposed aperture pairs of the other shaft member, whereby when the one tubular shaft member slides within the other tubular shaft member for length adjustment of the shaft, the pins retract during sliding and spring out and lock into a selected pair of apertures of the other member at a desired shaft length.

[0006] In one embodiment, the footrest apparatus includes a cam clamp attachable to the periphery of the other shaft member, the cam clamp including a lever operative in a first position to secure the other shaft member to the one shaft member at the desired shaft length and operative in a second position to release the other shaft member from the one shaft member for shaft adjustment.

[0007] In accordance with another aspect of the present invention, a method of adjusting footrest apparatus of a wheel chair comprises the steps of: attaching one end of a footrest shaft of the footrest apparatus to a structure of the wheel chair; attaching a footrest plate to the footrest shaft at the other end; providing a plurality of inline, spaced apart, diametrically opposed pairs of apertures along the sides of one of two telescoping tubular shaft members of the footrest shaft; providing a pair of diametrically opposed spring loaded pins to retract into and protrude through apertures at the outer surface of the other of the two tubular shaft members; and adjusting the length of the footrest shaft by sliding the other shaft member into the one shaft member with the pair of pins retracted into the apertures of the other shaft member until the pair of pins spring out and lock into a selected pair of apertures of the one shaft member at a desired shaft length. One embodiment of this aspect includes the steps of: attaching a cam clamp to the periphery of the one shaft member; securing the one shaft member to the other shaft member at the desired shaft length by moving a lever of the cam clamp to a first position; and releasing the one shaft member from the other shaft member for shaft adjustment by moving the lever of the cam clamp to a second position.

BRIEF DESCRIPTION OF THE DRAWING

[0008] Figures 1 and 2 taken together are a composite isometric, break away illustration of an individual right leg footrest apparatus for a wheel chair suitable for embodying the principles of the present invention.

[0009] Figures 1A and IB are cross-sectional illustrations of a cam clamp mechanism showing different levered positions.

[0010] Figures 3 and 4 taken together are a composite isometric, break away illustration of an individual left leg footrest apparatus for a wheel chair suitable for embodying the principles of the present invention.

[0011] Figure 5 is an isometric illustration of a portion of a wheel chair frame structure to which the right footrest apparatus may be attached in a hinge pin configuration for rotation between use and out-of-the-way positions.

[0012] Figure 6 is an isometric illustration of a portion of a wheel chair frame structure to which the left footrest apparatus may be attached in a hinge pin configuration for rotation between use and out-of-the-way positions.

DETAILED DESCRIPTION OF THE INVENTION

[0013] An exemplary embodiment of an individual footrest apparatus for use on a wheelchair is shown in the Figures 1, 1A, IB, and 2-4. Right and left leg footrest apparatus are shown in Figures 1 and 2 and Figures 3 and 4, respectively. Each of the right and left individual footrest apparatus comprises an upper tubular shaft member 10 shown in the break away, isometric drawing of Figures 1 and 3, and a lower tubular shaft member 12 and footrest plate 14 shown in the break away, isometric drawing of Figures 2 and 4. While Figures 1-2 and 3-4 shown individual right and left footrest apparatus, Figure 1-3 and 2-4 additionally show the upper and lower tubular shaft members 10 and 12, respectively, in reverse perspective so that both sides of the footrest shaft are revealed. Figures 1 and 3 additionally show a latching/unlatching mechanism 16 which is used to attach each upper tubular shaft member 10 to a respective structure of a wheel chair as will become more evident from the description supra.

[0014] In the present embodiment, each individual footrest apparatus comprises a footrest shaft including upper and lower tubular members 10 and 12, respectively, which are coaxially aligned to accommodate a sliding of the lower member 12 into the upper member 14 for length adjustment of the overall shaft 10,12. The upper shaft member 10 of the footrest apparatus is attachable to a structure of the frame of the wheelchair at its upper end 20 via the latching/unlatching mechanism 16 and has the footrest plate 14 attached at a lower end 22 of the lower member 12. As indicated above, the lower tubular member 12 slides telescopically inside the upper tubular member 10 for length adjustment to accommodate the user's leg. The upper tubular member 10 has a knee bend 23 at about two thirds of its length up from a bottom end 24. At a top end of the upper tubular member 10 is attached a hinge plate 26 in the shape of a partial horseshoe which is attachable to the mechanism 16 and wheel chair frame to permit the footrest apparatus to be rotated between use and out of the way positions as will become more evident from the description supra..

[0015] A support brace member 28 is attached by wielding or brazing, for example, to the upper member 10 just below the knee bend 23 and extends away from the upper tubular member 10 in the same direction as and substantially parallel to the bent upper third of the tubular member 10. The brace 28 is about the same length as the upper third of the member 10 and has another hinge plate 30 at its end which is shaped similar to the hinge plate 26 so that it may likewise be attachable to the wheel chair frame for footrest apparatus support and rotation. The plate 30 of the brace 28 has one end 32 of its partial horseshoe bent downward and the downward portion includes a tab 34 with a notch 36 for functioning as a latching tab when attached to the wheel chair frame for latching the footrest in the use position as will be better understood from the description below.

[0016] In the portion of the tubular member 10 below the knee bend 23 is provided a plurality of inline, spaced apart, diametrically opposed apertures or holes 40 on both sides thereof as shown by the perspectives of Figures 1 and 3. As shown in Figures 2 and 4, a pair of diametrically opposed spring loaded pins or buttons is embodied by a N-shaped spring member 42 having a pin or button 44 located at each tip of the N. Pins 44 may be solid buttons which are riveted to the tips of the N-shaped spring member 42 or may be shells stamped from the metal of the member 42, for example. The N-shaped member 42 is disposable into the lower tubular member 12 until the spring loaded pins 44 protrude from a pair of apertures or holes 46 at the outer surface near the top 48 thereof. Figures 2 and 4 show the aperture pairs 46 from both sides. When more than one pair of apertures 46 are used, the N-shaped spring member 42 is disposed into the tubular member 12 until the pins thereof protrude through a selected pair of apertures 46. While the illustration depicts the N-shaped member 42 being disposed into the member 12 N-shaped portion first, it is understood that the member 42 may just as well be disposed in the member 12 with the pin portion first, i.e. 180° to that shown by the illustration.

[0017] The apertures 46 and thus, pins 44 are disposed at the lower tubular member

12 to align with the pairs of apertures 40 in the upper tubular member 10 so that as the lower member 12 co-axially telescopes inside the upper member 10, the pins 44 retract during sliding and spring out and lock into selectively aligned holes 40 of the upper member 10 at different adjustable lengths of the footrest apparatus. In this manner, the footrest shaft 10,12 may be adjusted in length to the leg of the wheelchair user. Once locked in place by the spring loaded pins 44 and holes 40, the lower tubular member 12 of the footrest assembly can not be rotated about the axis of the shaft.

[0018] As shown in Figures 1 and 3, a cam clamp 50 is disposed at the upper tubular member 10, preferably at or near the bottom 24 thereof. The clamp 50 includes a lever 52 which is moveable about a pivot 54 into locking and unlocking positions as shown in the cross sectional views of Figures 1A and IB, respectively. When in the unlocked position or state (Figure IB), the clamp 50 permits telescopic movement of the shaft members 10 and 12 for length adjustment. After the footrest shaft 10,12 is adjusted to the desired length, the cam of the clamp 50 is forced against the surface of the lower member 12 by the movement of a clamp lever 52 to a locked position or state (Figure 1 A). In the present embodiment, the tubular shaft members 10 and 12 have circular cross sections of different diameters to accommodate sliding of one into the other. The clamp 50, when locked, prevents rattling between the shaft members 10 and 12 due to the difference in the diameters thereof. It is understood that the tubular shaft members may include other cross sectional shapes in alternate embodiments without deviating from the broad principles of the present invention. [0019] As shown in Figures 2 and 4, the lower tubular member 12 includes a tubular shaft 60 attached to a bottom end 62 thereof in such a manner to protrude out from the bottom end 62 at approximately a ninety degree angle to the shaft member 12. The footrest plate 14 is rotatably attachable to the tubular shaft 62 so as to be rotated about the tubular shaft 60 between a horizontal or in-use position as shown in Figures 2 and 4 and a vertical or out-of- the-way position (not shown) which is substantially parallel to the shaft member 12. The rotation will be counter-clockwise for the right leg embodiment of Figure 2 and clockwise for the left leg embodiment of Figure 4. Accordingly, in each embodiment, the footrest plate 14 may be positioned horizontally for use and vertically for rotating to an out of the way position. In the present embodiment, once the footrest plate or footplate 14 is rotatably disposed on the shaft 60, a set of screws 64 act as a stop to the movement of the plate 14 and a spring member 66 provides a friction or drag to movement between the plate 14 and shaft 60. An end cap 68 may be used to cover the shaft 60 and keep the plate 14 in place. In addition, a tube end cap 70 may be used to cover the end 62 of the tubular member 12. [0020] While the present embodiment illustrates an adjustable footrest shaft in which the lower tubular member 12 slides within the upper tubular member 10, it is understood that the reverse of this structure is also a suitable embodiment of the present invention. That is, the upper tubular member 10 may slide into the lower tubular member 12 for telescopic adjustment of the length of the shaft just as well without deviating from the broad principles of the present invention. In such an embodiment, the aperture pairs 40 would be disposed on the lower member 12 and the corresponding spring loaded pin assembly 42,44 would be disposed in apertures 46 in the upper member 10. Accordingly, in this embodiment, the footrest shaft 10,12 may be adjusted in length to the leg of the wheelchair user by sliding the upper tubular member 10 co-axially inside the lower tubular member 12 in which case the pins 44 of the upper member 10 retract during sliding and spring out and lock into selectively aligned holes 40 of the lower member 12 at different adjustable lengths of the footrest assembly.

[0021] Referring back to Figures 1 and 3, the mechanism 16 includes a housing 72 having sets of apertures or holes 74 to accommodate holes in the plate 26 of the upper member 10 for attachment and support purposes. A screw 76 and rivnut 78 are used with one set of apertures 74 and a screw 80, bushing 82, spring release 84, and nut 86 are used with another set of apertures 74 to attach plate 26 to the housing 72 utilizing the holes therein. A protective plastic tip 90 may be disposed over the lever 18. An end cap 92 may be disposed over the end of the member 10 above the bend as an anti-rattle mechanism. [0022] In the present embodiment, each individual footrest apparatus 10 is coupled to a corresponding frame member of the wheel chair, preferably a corresponding front right and left leg member thereof, through a hinge pin configuration, for example. Referring to Figure 5, a front right leg frame member 100 includes two spaced apart hinge plates 102 and 104 brazed or wielded thereto. The spacing 106 between the plates 102 and 104 corresponds to the spacing between the hinge plates 26 and 30 of the footrest apparatus 10. Each hinge plate 102 and 104 includes a pin 108 and 110, respectively, at one end thereof and disposed vertically to the top surface of its respective plate. Holes 112 and 114 are disposed at one end of the plates 26 and 30, respectively, and aligned respectively with the pins 108 and 110. Accordingly, plates 26 and 30 may be coupled respectively to plates 108 and 110 in a hinge pin configuration by engaging pins 108 and 110 into holes 112 and 114, respectively. Thus, plates 26 and 30 may slidably rest respectively on plates 102 and 104 of the wheel chair frame member 100 and rotate about pins 108 and 110 to accommodate the footrest apparatus 10 between use and out-of -the -way positions thereof.

[0023] When the footrest apparatus is moved to the use position, the latching mechanism 16 causes the plate 26 to be latched to the plate 102 and the lever 18 is forced into a latched position via double headed spring clip 84. Also, in the use position, plate 104 is disposed into the notch 36 of plate 30 to provide additional support for the footrest apparatus. When the lever 18 of mechanism 16 is moved momentarily away from its latched position, the plate 26 is unlatched from the plate 102 and the footrest apparatus is permitted to rotate about pins 108 and 110 to the out-of-the-way position.

[0024] A similar hinge pin configuration is provided for the left footrest apparatus.

Referring to Figure 6, a front left leg frame member 120 includes two spaced apart hinge plates 122 and 124 brazed or wielded thereto. The spacing 126 between the plates 122 and 124 corresponds to the spacing between the hinge plates 26 and 30 of the left footrest apparatus 10. Each hinge plate 122 and 124 also includes a pin 128 and 130, respectively, at one end thereof and disposed vertically to the top surface of its respective plate. Holes are similarly disposed at one end of the plates 26 and 30, respectively, of the left footrest apparatus and aligned respectively with the pins 128 and 130. Accordingly, the hinge pin configuration for the left footrest apparatus will operate in a similar manner as described above for the right footrest apparatus for movement between use and out-of-the-way positions.

[0025] While the individual footrest apparatus has been described above as being attached to a frame member of the wheel chair by a hinge pin configuration, it is understood that other configurations could be used for attachment purposes without deviating from the broad principles of the present invention. In addition, a calf pad may be added to one or both of the individual footrest apparatus for leg support without deviating from the present invention.

[0026] In summary, the footrest apparatus of a wheel chair may be adjusted by a method comprising the steps of: attaching one end 10 of a footrest shaft 10,12 of the footrest apparatus to a structure of the wheel chair; attaching a footrest plate 14 to the footrest shaft 10,12 at the other end 12; providing a plurality of inline, spaced apart, diametrically opposed pairs of apertures 40 along the sides of one 10 of two telescoping tubular shaft members 10,12 of the footrest shaft; providing a pair of diametrically opposed spring loaded pins 44 to retract into and protrude through apertures 46 at the outer surface of the other 12 of the two tubular shaft members; and adjusting the length of the footrest shaft by sliding the other shaft member 12 into the one shaft member 10 with the pair of pins 44 retracted into the apertures 46 of the other shaft member 12 until the pair of pins 44 spring out and lock into a selected pair of apertures 40 of the one shaft member 10 at a desired shaft length. One embodiment of this aspect includes the steps of: attaching a cam clamp 50 to the periphery of the one shaft member; securing the one shaft member to the other shaft member at the desired shaft length by moving a lever 52 of the cam clamp 50 to a first position; and releasing the one shaft member from the other shaft member for shaft adjustment by moving the lever 52 of the cam clamp 50 to a second position.

[0027] While the footrest apparatus has been described above in connection with a number of embodiments, it is understood that such embodiments are presented merely by way of example and should not be used to limit the invention in any way, shape or form. Rather, the present invention should be construed in breadth and broad scope in accordance with the recitation of the set of claims appended hereto.

Claims

CLAIMSWhat is claimed is:

1. Footrest apparatus for use on a wheel chair, said apparatus comprising: a footrest shaft comprising two tubular members coaxially aligned to accommodate a sliding of one of said two tubular members within the other for length adjustment of said shaft, said footrest shaft being attachable to a structure of the wheel chair at one end; a footrest plate attachable to the footrest shaft at the other end; the other of said two tubular shaft members having a plurality of inline, spaced apart, diametrically opposed pairs of apertures along the sides thereof; and the one of said two tubular shaft members having a pair of diametrically opposed spring loaded pins which retract into and protrude through apertures at the outer surface thereof, said pins being aligned with the diametrically opposed aperture pairs of the other shaft member, whereby when the one tubular shaft member slides within the other tubular shaft member for length adjustment of the shaft, the pins retract during sliding and spring out and lock into a selected pair of apertures of the other member at a desired shaft length.

2. The footrest apparatus of claim 1 including a cam clamp attachable to the periphery of the other shaft member, said cam clamp including a lever operative in a first position to secure the other shaft member to the one shaft member at the desired shaft length and operative in a second position to release the other shaft member from the one shaft member for shaft adjustment.

3. The footrest apparatus of claim 2 wherein the cam clamp is attachable at an end of the other shaft member into which the one shaft member slides.

4. The footrest apparatus of claim 1 wherein the one end of the footrest shaft being attachable to the wheel chair structure through a latching/unlatching mechanism comprising a first mechanical assembly attached to the one end of the footrest shaft for attaching the shaft to the wheel chair, said first assembly including a latching tab for engaging and disengaging said first mechanical assembly with said wheel chair structure.

5. The footrest apparatus of claim 1 wherein the other shaft member is attachable at one end to the structure of the wheel chair, said one end of the other shaft member including a hinge plate in the shape of a partial horseshoe which is rotatably attachable to another hinge plate on the structure of the wheelchair to permit the footrest apparatus to be rotated between use and out-of-the-way positions.

6. The footrest apparatus of claim 5 wherein the other shaft member has a knee bend at about two thirds of its length from the other end and includes a support brace member attached thereto just below the knee bend and extending from the other shaft member in the same direction as and substantially parallel to the bent upper third of the other shaft member, said support brace member being about the same length as the upper one third of the other shaft member and including a hinge plate end shaped similar to the hinge plate of the other shaft member and engageable with a corresponding hinge plate on the structure of the wheelchair for footrest apparatus rotation, said plate end of the support brace member having a portion of one leg of its partial horseshoe bent downward, and the downward portion including a tab with a notch for functioning as a latching tab when engaged with the corresponding hinge plate on the structure of the wheelchair.

7. The footrest apparatus of claim 1 wherein the one shaft member includes a tubular shaft attached to the bottom thereof and which protrudes out from the one member at approximately a ninety degree angle, the footrest plate being rotatably attachable to the tubular shaft so as to be rotated between horizontal and vertical positions.

8. The footrest apparatus of claim 1 wherein the one and other tubular shaft members are circular in cross section.

9. The footrest apparatus of claim 1 wherein the pair of spring loaded pins comprises a N-shaped spring member having a pin located at each tip of the N-shaped member, said N- shaped spring member being disposable into the one tubular shaft member until the pins thereof protrude through the pair of apertures of the one tubular shaft member.

10. The footrest apparatus of claim 9 wherein the one tubular shaft member includes more than one pair of apertures; and wherein the N-shaped spring member being disposable into the one tubular shaft member until the pins thereof protrude through a selected pair of the more than one pair of apertures.

11. Method of adjusting footrest apparatus of a wheel chair, said method comprising the steps of: attaching one end of a footrest shaft of the footrest apparatus to a structure of the wheel chair; attaching a footrest plate to the footrest shaft at the other end; providing a plurality of inline, spaced apart, diametrically opposed pairs of apertures along the sides of one of two telescoping tubular shaft members of the footrest shaft; providing a pair of diametrically opposed spring loaded pins to retract into and protrude through apertures at the outer surface of the other of the two tubular shaft members; and adjusting the length of the footrest shaft by sliding the other shaft member into the one shaft member with the pair of pins retracted into the apertures of the other shaft member until the pair of pins spring out and lock into a selected pair of apertures of the one shaft member at a desired shaft length.

12. The method of claim 11 including the steps of: attaching a cam clamp to the periphery of the one shaft member; securing the one shaft member to the other shaft member at the desired shaft length by moving a lever of the cam clamp to a first position; and releasing the one shaft member from the other shaft member for shaft adjustment by moving the lever of the cam clamp to a second position.

13. The method of claim 12 including attaching the cam clamp at an end of the one shaft member into which the other shaft member slides.

14. The method of claim 1 including the step of attaching a first mechanical assembly at the one end of the footrest shaft to the wheel chair structure through a latching/unlatching mechanism by engaging and disengaging a latching tab of the first mechanical assembly with said mechanism.

15. The method of claim 14 including the step of rotating the footrest apparatus between use and out-of-the-way positions by engaging and disengaging the locking tab of the first mechanical assembly with the latching/unlatching mechanism.

16. The method of claim 1 including the step of rotating the footrest plate between horizontal and vertical positions for use and out-of-the-way positions of the footrest apparatus, respectively.

17. The method of claim 1 including the step of disposing a N-shaped spring member having a pin located at each tip of the N-shaped member into the other tubular shaft member until the pins thereof protrude through the pair of apertures of the other tubular shaft member.

18. The method of claim 17 wherein more than one pair of apertures is provided in the other shaft member; and wherein the N-shaped spring member is disposed into the other tubular shaft member until the pins thereof protrude through a selected pair of the more than one pair of apertures.