WO1991013603A1

WO1991013603A1 - Wheelchair lift

Info

Publication number: WO1991013603A1
Application number: PCT/CA1990/000446
Authority: WO
Inventors: Glen W. Waddell
Original assignee: Waddell Glen W
Priority date: 1990-03-14
Filing date: 1990-12-14
Publication date: 1991-09-19
Also published as: CA2012128A1; AU6907591A

Abstract

A wheelchair support and elevating apparatus (10) comprising a lower or base frame (12), an upper, load supporting frame (14), elevating arms (16 and 18) interconnecting the base frame (12) and the load supporting frame (14), a motor (34) for actuating the elevating arms (16 and 18) to raise the upper, support frame (14) to elevated positions with respect to a support surface, a pivot pin (116) for tilting the load supporting frame (14) about a horizontal axis, a support shaft (98) for rotating the load supporting frame (12) about a vertical axis and stabilizers (26 and 28) for stabilizing the lower or base frame (12).

Description

WHEELCHAIR LIFT

FIELD OF THE INVENTION

This invention pertains to lifting devices and in particular to a wheelchair lifting device that is compact and easily portable and which allows for the elevation, rotation and tilting of a wheelchair and its occupant.

BACKGROUND OF THE INVENTION

Transportation and access to various services such as physicians, dentists, barbers, etc. pose serious difficulties for handicapped persons confined to wheelchairs. Specifically, the transfer of the person from wheelchair to examination table, or dentists chair, is a process requiring a great deal of effort. To aid in the situation, numerous wheelchair lift devices have been developed for providing the dentist (for example) access to the non-ambulatory person, eliminating the need for transfer of the person out of the wheelchair.

For example, Rachman discloses a portable wheelchair tilting device in U.S. Patent No, 4,830,567 (issued May 16, 1989); however, in this device raising and rotating of the wheelchair is not possible.

Similarly in U.S. Patent No, 4,759,684 (issued July 26, 1988) Lanzillotta et al disclose a wheelchair lift device which raises, rotates and tilts the wheelchair. Although the device disclosed by Lanzillotta et al is similar in function to the present invention, it differs in that it is not portable.

Prior art in the field of wheelchair lift devices is relatively extensive. In addition to the devices disclosed in the aforementioned patents, other similar devices have also been developed, for example:

McConnell, U.S. Patent No, 4,790,716 (issued December 13, 1988);

McConnell, U.S. Patent No. 4,726,730 (issued February 23, 1988);

Peterson, U.S. Patent No. 4,192,549 (issued December 31 1985); Norton, U.S. Patent No. 4,561,823 (issued December 31, 1985);

McConnell, U.S. Patent No, 4,592,695 (issued June 3, 1986);

Zimmerman et al, U.S. Patent No. 4,725,188 (issued February 16, 1988); and

Rachman, U.S. Patent No, 3,476,404 (issued November 4, 1969). SUMMARY OF THE INVENTION

The present invention addresses the above-described problems of conventional wheelchair lifting devices and provides a means for supporting and raising a wheelchair and which, once raised, can be rotated or tilted as required. The device includes a base frame and a support or lifting frame on which support tracks are attached. A wheelchair is wheeled on to the support tracks and a lifting mechanism interconnecting the base frame and lifting frame is actuated by suitable motor means to raise and lower the lifting or support frame and the wheelchair and occupant thereon. The base frame is provided with means for stabilizing the assembly to inhibit tipping of the device once the wheelchair is in a raised position.

According to a broad aspect the invention relates to a wheelchair support and elevating apparatus comprising a lower or base frame, an upper, load supporting frame, elevating means interconnecting said base frame and said load supporting frame, motor means for actuating said elevating means to raise said upper, support frame to elevated positions with respect to a support surface, means for titling said load supporting frame about a horizontal axis, means for rotating said load supporting frame about a vertical axis and means for stabilizing said lower or base frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by way of example in the accompanying drawings in which: FIGURE 1 is a plan view of the assembly;

FIGURE 2 is an elevation view in section as seen from lines 2-2 of FIGURE 1;

FIGURE 3 is fragment end and elevation view;

FIGURE 4 is a perspective view of the assembly in a raised position; and

FIGURE 5 is a fragmentary, perspective view of a portion of the support frame. DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, the wheel chair lift assembly is indicated generally at 10 and includes a lower base frame 12 and an upper, moveable frame 14. Briefly, it will be seen from FIGURE 2 that the upper frame 14 is connected to the lower frame 12 by means of two pairs of arms 16, 18, which, when moved from a horizontal position (FIGURE 3) to intermediate and uppermost positions (FIGURES 2 and 4) serve to elevate the upper frame 14 from the base frame.

Base frame 12 comprises an elongated, trough-like structure formed by a bottom wall 20, side walls 22 and 24 and end walls provided by lateral stabilizers 26 arid 28 respectively. As seen in FIGURES 1 and 4, stabilizer 28 is itself of box-like configuration including side walls 30 and 32 and is of a size sufficient to accommodate motor means indicated generally at 34 for actuating the mechanism to raise and lower the upper frame 14. It will also be noted that stabilizer 28 includes suitable rollers or wheels 36 and that stabilizer 26 at the other end of the assembly includes a tongue 38. It will be understood that tongue 38 allows for the connection of a suitable form of towing means which may be utilized to lift the tongue end of the assembly and, due to the provision of the rollers 36, the assembly can be easily moved about.

The upper frame 14 is the member of the assembly which is moved from a lower, rest position to an upper, raised position as shown in FIGURE 4, and upper frame 14 carries the full load of a wheel chair or the like and its occupant. Frame 14 comprises a central portion 40 preferably constructed of high strength alloy rectangular tubing and is of elongated rectangular configuration having side rails 42, 44, spaced and interconnected by cross members 46, 48 and 50 as shown in FIGURES 1 and 2. Cross members 46 and 50 include downwardly and outwardly extending leg members 52, 54 which are provided at their lower terminal ends with laterally extending tubular members 56 and 58 respectively.

As seen clearly in FIGURE 1, the upper frame 14 supports a pair of spaced parallel elongated tracks 60 and 62. These tracks receive the wheels of a wheelchair and each track is wide enough to accommodate some deviation of line when a wheelchair is being run on to the tracks when the frame 14 is at the lowermost or ground level as seen in FIGURE 3. Each track 60, 62 has short side walls 64 and end walls 66 as well as a rectangular opening 68 adjacent the entrance end of the tracks. It will be evident that the large wheels of a wheelchair drop into the openings 68 when the upper frame 14 is raised above ground level and this prevents the wheelchair from moving fore and aft on the tracks 60, 62.

In order to adjust the lifting frame 14 to accommodate wheelchairs of varying tracks widths, tracts 60 arid 62 are adjustably mounted to the legs 52, 54 of frame 40. As shown in FIGURES 1 and 5, tracks 60 and 62 are each provided with a pair of inwardly extending arms 70, 72 respectively and these arms are accommodated in the tubular members 56 and 58 at the lower ends of arms 52 and 54 as shown and are secured therein by means of suitable retaining means such as wing nuts 74, 76 or the equivalent. It would be appreciated that by loosing off the wing nuts the tracks 60 and 62 can be moved toward or away from one another to accommodate the various track widths of wheel chairs of different sizes.

Turning now to FIGURES 2 and 3, apparatus is provided for raising and lowering the upper frame 14 and for maintaining that frame in a desired position with respect to the lower or base frame 12. This apparatus includes the arms 16 and 18 which are pivotally connected at their lower ends to front and rear captive nuts 78 and 80 which are located in the lower, base frame 12 by means of longitudinally extending guide rods 82 and 84 which are secured at their ends to the stabilizer ends of the base frame 12.

As shown in FIGURES 1 and 2, the motor means 34 is connected to an elongated shaft 86 located in the lower or base frame 12 between the guide rods 82 and 84. The motor means is connected to shaft 86 through a suitable coupling means 88 (FIGURE 2) and shaft 86 is threaded throughout its length and is engaged thereby in the captive nuts 78 and 80 in the base frame 12. It will be understood that rotation of the threaded shaft 86 by the motor means 34 will cause the captive nuts 78, 80 to be either drawn towards one another thereby raising the upper frame 14 through the action of the interconnecting arms 16 and 18 or moved away from one another towards the ends of the lower frame 12 to effectively lower the frame 14.

Upper frame 14 is carried by a support assembly indicated generally at 90 in FIGURE 2. Assembly 90 includes a connector block 92 to which the upper ends of arms 16 and 18 are connected by means of pivot pins 94, the upper ends of arms 16 and 18 having meshing geared portions 96, as shown, so that the arms act in unison in raising and lowering functions.

Connector block 92 includes a vertically oriented central shaft 98 with a reduced diameter spindle 100. Shaft 98 is provided with a thrust bearing 102 which takes the load of a pivot block 104 mounted thereon and block 104 is mounted for rotation on spindle 100 by means a suitable bearing 106. Block 104 is retained in position on the shaft 98 and spindle 100 by means of a hold down nut and washer 110.

A top plate 112 is secured to a sleeve 114 which is mounted on a pivot pin 116 secured in a channel 118 of block 104. The members 42, 44 or top frame 14 are then secured, preferably detachably so, to the plate 112 to complete the support assembly 90.

It will be apparent that with the above mentioned connection of the upper frame 14 to plate 112 that frame 14 can be tilted upwardly with respect to the unit by means of the pivot pin 116 in the sleeve 114. Additionally, through the provisions of bearings 106 and 102, upper frame 14 can be rotated on a horizontal plane with respect to the lower, base frame 12 and, in order to retain the upper frame 14 in several positions in such a horizontal plane, block 92 may be provided with a series of indentations (not shown) to receive a ball detent 120 biased to a retaining position by means of a suitable spring 122 located in the body of block 104.

In operation, the upper frame is located at a ground or support level as shown in FIGURE 3. A wheelchair and its occupant is moved on to the track 60 and 62 until the main wheels of the wheelchair are located over the openings 68. The motor means 34 is then actuated to rotate the threaded shaft 86 drawing the captive nuts 78 and 80 toward one another, effecting inward movement of the lower ends of arms 16 and 18 thereby raising the support assembly 90 and the upper frame 14 with the wheelchair and its occupant thereon. When the desired elevation is reached, the upper frame can be rotated to the desired orientation and tilted rearwardly if so desired.

The fact that the lifting device of this invention is so easily storable and portable is a most important feature. In its lower, inoperative position the assembly is quite low in elevation and, when placed on its edge and utilizing caster wheel 25 and fixed trailing wheels 27 mounted on end wall 30, it can be easily stored in a closet or coat rack area of a home or that of a physician's or dentist's office, barber shop, hairdresser shop or the like and from which it can quickly be removed to accommodate a patient or client who is wheelchair-confined.

Additionally, the unit can easily fit into the truck or rear seat area of most vehicles.

A small lightweight towing handle 39 can be snapped onto the tongue or hitch 38 and, with the stabilizer legs and feet 29 moved to an upper position, the assembly with a wheelchair and occupant in place on the upper frame 14 can be easily and quickly manoeuvred to a desired location. While the invention has been described in connection with a specific embodiment thereof and in a specific use, various modifications thereof will occur to those skilled in the art without department from the spirit and scope of the invention as set forth int he appended claims.

The terms and expressions which have been employed in this specification are used as terms of description and not of limitations, and there is no intention in the use of such terms and expressions to exclude any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A wheelchair support and elevating apparatus comprising a lower or base frame, an upper, load supporting frame, elevating means interconnecting said base frame and said load supporting frame, motor means for actuating said elevating means to raise said upper, support frame to elevated positions with respect to a support surface, means for titling said load supporting frame about a horizontal axis, means for rotating said load supporting frame about a vertical axis and means for stabilizing said lower or base frame.

2. The apparatus according to claim 1 wherein said elevating means comprises a threaded shaft in said base frame with motor means for rotating said threaded shaft, a pair of captive nuts, one at either end of said base frame and mounted on said threaded shaft for movement along said base frame responsive to rotation of said shaft, a pair of arms pivotally located at one of their ends to a respective one of said captive nuts, a support assembly pivotally connected to the upper ends of said arms whereby rotation of said threaded shaft effects raising or lowering of said arms and the support assembly on the upper end thereof.

3. Apparatus according to claim 2 wherein said support assembly comprises means for detachably connecting said upper support frame to said arms and comprises a connector block interconnecting the upper ends of said arms, shaft means on said connector block, a pivot block mounted for rotation on said shaft means, plate means pivotally mounted on said pivot block for rotation about a horizontal axis, and said upper support frame being detachably connected to said plate means.