Abstract
A transferable wheelchair width adjuster that can be attached to the lower frame of a folding wheelchair allowing the wheelchair to be narrowed to varying widths so as to accommodate entry through doorways that otherwise would be impassable. Narrowing the profile of a standard wheelchair also allows the chair to accommodate more comfortably a smaller individual, such as a small child. No modification of the original wheelchair construction is necessary. The width adjuster described herein can be attached and removed manually without the need of tools.
Claims
1. A relatively small, portable device that can be attached to a folding wheelchair to narrow its width by connecting the lower cross members of a wheelchair frame resulting in a configuration narrower than that produced when the wheelchair was manufactured.
2. A device that is manually adjustable using opposing snap buttons to provide variable widths for a folding wheelchair depending on the degree of narrowing that is required for a particular application.
3. (canceled)
4. (canceled)
5. A device that can be installed on an existing folding wheelchair manually without requiring the use of tools.
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view showing primary components of a standard folding wheelchair.
[0028] FIG. 2 is a perspective view of a folding wheelchair with the wheelchair frame shaded for reference.
[0029] FIG. 3 is a perspective view of a folding wheelchair with the wheelchair cross brace shaded for reference.
[0030] FIG. 4 is a side view of the assembled wheel chair adjustment invention.
[0031] FIG. 5 is a perspective view of the outer tubular component of the wheelchair adjuster.
[0032] FIG. 6 is a side view of the inner tubular component of the wheelchair adjuster.
[0033] FIG. 7 is a side view of the threaded compression fitting and U-shaped retention hook for attaching the inner tubular component to the lower wheelchair frame.
[0034] FIG. 8 is a side view of the threaded compression fitting and U-shaped retention hook for attaching the outer tubular component to the lower wheelchair frame.
[0035] FIG. 9 is a side view of the assembled wheelchair width adjuster revealing the length-locking button contained within the inner tubular component protruding through a perforation in the outer tubular component.
[0036] FIG. 10 is an expanded cross-sectional view of the snap button assembly housed in the inner tubular component under locking compression with buttons protruding from opposing perforations in the outer tubular component.
[0037] FIG. 11 is an expanded view of the snap button assembly.
[0038] FIG. 12 is a frontal view of a standard folding wheelchair at its full extension.
[0039] FIG. 13 is a frontal view of a standard folding wheelchair locked into a narrower width position after attachment of the width adjusting invention herein described.
DETAILED DESCRIPTION OF THE INVENTION
[0040] Examining the drawings in detail, FIG. 1 illustrates several components of a typical folding wheelchair, including the back support 1, push handle 2, padded armrest 3, seat cushion 4, seat sling 5, right and left rigid frames 6, x-shaped cross brace 7, pneumatic tire attached to frame 8, and hand rim for propelling chair 9. For a more complete description of all the components of a typical manual folding wheel wheelchair see reference cited by Dr. D. Michael McKeough (2007) who granted permission to use figures from his publication as FIG. 1, FIG. 2, and FIG. 3 in this application. For purposes of this application, the most critical elements are shown shaded for clarity in FIG. 2 and FIG. 3, i.e. the rigid side frames 6 in FIG. 2 and the x-shaped cross brace 7 that connects the frames in FIG. 3. Most attempts to modify the basic design of a folding wheelchair to narrow its width to permit passage through a narrow doorway have focused on alterations to the side frames or the x-shaped cross brace as previously discussed in the BACKGROUND OF THE INVENTION section.
[0041] FIG. 4 represents a frontal view of the assembled device proposed in this patent application. The two primary telescoping components include an outer tubular element 8 and an inner tubular element 9. U-shaped supports for attaching the device to the lower parts of the rigid cross braces FIG. 3. are firmly attached to the ends of the inner tubular element 10 as well as the outer tubular element 11. The outer tubular element 8 contains numerous perforations along its length 14 that correspond to matching perforations 14 on the opposite side of the tubular element 8. One of the two complementary snap buttons is shown protruding from one of the perforations 15.
[0042] A more detailed perspective drawing of the outer tubular element 8 is shown in FIG. 5. While a perfectly circular tubular outer element may be adequate in most applications for this device, an optional embodiment is modifying the top 17 and bottom 18 of the outer tubular element 8 to include axially-incised ridges that strengthen the outer tubular structure 8. By depressing the snap buttons 15 while holding firmly the outer tubular element 8 and twisting the inner tubular element 9 in FIG. 6 slightly, the snap buttons 15 are compressed against the inner wall of the outer tubular element 8 and can be easily slid into a new position. Once positioned at the appropriate perforation location for the desired length, the inner tubular structure 9 is rotated slightly until the snap buttons 15 engage the outer tubular perforations 14 and lock the device in place at the desired length.
[0043] At opposing ends of both the outer tubular element 8 and the inner tubular element 9 are U-shaped hooks 10 and 11 for attaching the device to the horizontal members of the wheelchair frames 6 in FIG. 2. The U-shaped hooks 10 and 11 may be attached to outer tubular element 8 and inner tubular element 9 in a variety of ways. One method is shown in FIG. 7 and FIG. 8 whereby threaded U-shaped hooks 10 and 11 are screwed into threaded plugs 12 and 13 that are held by compression in the ends of the outer tubular element 8 and the inner tubular element 9.
[0044] FIG. 9 shows the assembled elements of the adjusting device proposed herein, i.e. the outer tubular element 8 with its attached U-shaped hook 11, the inner tubular element 9 with its attached U-shaped hook 10, and the protruding snap button 15. FIG. 10 illustrates a longitudinal cross-sectional view of the snap button assembly 16 installed in tubular element 9 showing buttons 15 protruding through perforations in the outer tubular element 8 that serves to lock the adjusting device in its desired position.
[0045] FIG. 11 illustrates a perspective view of the uncompressed snap assembly spring 16 with its attached snap buttons 15 that is inserted into the end of inner tubular element 9 until it snaps into place through perforations near the end of inner tubular element 9.
[0046] FIG. 12 illustrates a folding wheelchair with the sling seat 5 at its maximum width and the rigid side frames 6 at their fullest extension. When the sling seat 5 is raised (indicated by the shaded arrow) to a position represented by the dashed line, the rigid side frames 6 will be pulled towards one another (indicated by the open unfilled arrows) and the X-shaped cross brace will be compressed.
[0047] FIG. 13 illustrates the resultant configuration of a narrowed folding wheelchair. The sling seat 5 sags slightly downward as the overall profile of the folding chair is narrowed. Once the desired width is determined, the tubular adjustable device described herein containing components 8, 9, 10, 11, and 15 is adjusted in length to agree with the width desired and placed manually over the lowermost members of the frame to lock the width securely in place as shown by the simplified shaded device attached to the wheel chair in FIG. 13.
