Wheelchair lift

Abstract

A vehicle-mounted device for use in moving a wheelchair and its occupant to and from the bed of a vehicle, comprising a platform for supporting the wheelchair, two parallelogram linkages having base links secured in place in the vehicle and end links carried by elongated arms swinging in space vertical planes, and means securing the platform the platform being secured to the end links for movement in a generally horizontal attitude along an arcuate path so that one edge of the platform passes close to the edge of the bed of the vehicle at the access opening, and engages a stop in the vehicle for folding the platform into a storage position as the linkages complete their arcs. A motorized chain-and-sprocket drive swings the linkages between lowered, outwardly extending positions and raised, upright storage positions in the vehicle, and controls are provided for operating the drive and stopping the platform in an intermediate, entry position level with the bed. A first embodiment has the base and end links horizontal, the platform carried on upright posts, and a second embodiment has the end and base links upright.

Description

The present application is a reissue application of U.S. Pat. No. 3,913,759. engaged brings the platform to the entry position as movement stops.

Similarly, when the platform 15 has been boarded from the van 11 in the entry position, the switch 89 is used to lower the platform to the ground. For this purpose, the switch arm 90 is moved down to the contact 92 to complete a down circuit from the battery 46 to the down coil 72, through the lines 73 and 93, the switch 89, a line 99 leading to the normally closed "ground" switch 75, and the line 77 to the coil. Thus, the down motor switch 70 is closed to lower the platform until the ground switch is opened, by sagging of the chain 51 onto the switch operator 79.

Movement of the platform 15 to and from the storage position by a person inside the van 11, after entering the van or preparatory to existing, is controlled by a third manual switch 100, preferably mounted on the front of the motor cover 62 inside the van. This switch also has an arm 101 with a neutral position between two contacts 102 and 103. When the switch is moved up to the contact 102, an up circuit is completed to the motor 48 through the line 68 and the motor switch 85, which is closed upon energization of the coil 84 through a circuit including the line 68, a line 104 leading to the switch 100, a line 105 leading to the line 80 that is connected to the normally closed upper limit switch 81, and the line 83 to the coil 84. When the platform reaches the storage position, the arm 21 opens the switch 81 to stop the motor 48.

When the platform 15 is to be lowered from the storage position, the inside switch 100 is moved down to the contact 103, which completes a circuit from the battery 46 to the down coil 72 through a normally closed switch 107 having an operator 108 along the path of the upper arm 21 of the linkage 19, this circuit including the lines 68 and 104, a line 109 from the contact 103 to the switch 107, and a line 110 leading to the line 77 connected to the down coil, which closes the down motor switch 70.

This switch 70 remains closed as the platform 15 is lowered, until the arm 21 engages the switch operator 108 and opens the switch 107 to break the circuit, just before the platform reaches the entry position, so that the predictable overrun positions the platform for entry from the van.

The two switch operators 98 and 108 for terminating raising and lowering as the platform 15 approches the entry position are mounted on the side of the motor cover 62, as shown in FIGS. 1 and 2, and preferably are adjustable for selection of the proper position for engagement with the linkage arm 21. The operators project through an inclined elongated slot 111, which accommodates such adjustment.

It should be understood that this circuitry is merely one possible arrangement for controlling the lift 10 of the present invention, and that other circuits could be devised to accomplish the necessary control. The important functions are to provide for manual actuation through the various motions, and preferably automatic stopping in the entry position for movement of the wheelchair into and out of the van. The illustrative controls have been found to be satisfactory for these purposes.

DESCRIPTION OF THE ALTERNATIVE EMBODIMENT

Shown in FIG. 13 is an alternative embodiment of the invention, which is of somewhat simplified and more compact construction. For ease of description, parts of this embodiment which correspond to parts of the first embodiment are identified by corresponding primed reference numbers, and only the significant differences are described in detail.

In this instances, the lift 10' comprises a pair of parallelogram linkages 19' (one being shown) that are mounted in the van 11' on two upright support posts 45' which serve as the base links of the linkages, eliminating the links 20. These posts preferably have a slight forward incline.

Two parallel arms 21' and 22' are pivoted on each support post 45', on vertically spaced pins 23' a substantial distance below the upper ends of the posts. The end links of the linkages are formed by upright posts 27', pivotally connected to the free ends of the arms 21', 22' by spaced pins 25'. The posts 27' have downward extensions, which are pivotally connected to the platform, as before. The posts 27', being parallel to the posts 45', also have a slight forward incline.

The platform 15' has rollers 42' at its leading corners for engagement with stationary camming surfaces 41' in the van, and thus is folded upwardly into a storage position, as before. The other operating and control elements are provided in the same general manner as in the first embodiment, with such minor modifications as are necessary to adapt them to the modified linkage arrangement.

It will be seen that this embodiment utilizes the inside posts 45' and the outside posts 27' as the base and end links of the parallelogram linkages 19', and uses shorter arms 21' and 22' than those in the first embodiment. The arc of movement is shorter, as indicated by the dotted lines in FIG. 13, but the second embodiment performs the same functions as the first embodiment, and has the same basic advantages. The downward extensions of the end links serve the same purpose as the posts 27, and the upward extensions of the base links serve the functions of the support posts 45.

From the foregoing, it should be evident that the present invention provides a practical, sturdy and conveniently operated wheelchair lift which makes it possible even for a severely handicapped person of reduced strength and manipulative ability to enter and exit from a vehicle. At the same time, the lift is relatively simple in construction, and folds compactly into the vehicle when not in use.

It also will be evident that, while two specific embodiments of the invention have been illustrated and described, various modifications and changes may be made without departing from the spirit and scope of the invention.

Claims

1. A wheelchair lift mountable in a vehicle adjacent an access opening thereof, for use in moving a wheelchair and its occupant to and from a generally horizontal bed of the vehicle, comprising:

a pair of spaced parallelogram linkages each having a base link mountable in said vehicle adjacent the access opening, two side-by-side elongated arms pivotally mounted on said base link for swinging about spaced, parallel axes between upright positions in the vehicle, in which the arms extend upwardly from said base links, and lowered positions in which said arms project out of the vehicle through the access opening, and an end link parallel to said base link and pivotally mounted on the ends of said arms opposite the base link;

said linkages being spaced apart for mounting in the vehicle adjacent opposite sides of the access opening for swinging in substantially parallel planes, and to leave a passageway for a wheelchair between the linkages;

a flat and generally rectangular platform sized to support a wheelchair, said platform having one edge disposed beneath the said end links when said arms are in said lowered positions;

posts extending from said end links down to said platform;

a pivot connecting each of said posts to said platform for tilting of the platform about an axis above, and extending along, said one edge;

first stop means carried by said posts and acting against said platform to hold the platform against downward tilting from a generally horizontal operating position, but permitting upward tilting of the platform;

said posts being of a preselected length for supporting said platform at ground level when said arms are in the extended position, and for moving said one edge along an arc passing closely adjacent the edge of the bed at the access opening, and past the edge through the opening;

drive means for selectively swinging the arms of said linkages from said lowered positions to said upright positions and back;

control means for actuating said drive means and for stopping said linkages in each direction of movement with said platform in an intermediate position level with the bed, for movement of a wheelchair into and out of the vehicle;

and cam means positioned along said arc adjacent said base links for engagement with said one edge after the latter passes through the access opening and as the arms of said linkages swing into said upright positions, and operable to force said one edge downward to tilt said platform upward into a storage position.

2. A wheelchair lift as defined in claim 1 in which said drive means includes a reversible motor, and a chain-and-sprocket drive including at least one length of chain having one end connected to one of said linkages adjacent the end link thereof, and a sprocket for said chain supported inside the vehicle and driven by said motor, said chain extending from said end link to said sprocket and being engaged with the latter to be fed longitudinally in opposite directions by said sprocket, thereby to swing said linkages between said positions.

3. A wheelchair lift as defined in claim 2 further including a resiliently extendable spring connecting said chain to said linkage.

4. A wheelchair lift as defined in claim 2 further including two support posts extending upwardly from said base links, said drive means including sprockets rotatably mounted on the upper end portions of said posts, a chain on each of said sprockets having a first end portion hanging downward and a second end portion extending from the sprocket to the associated end link, and connected to the latter, and a motor for driving said sprockets to feed said chains longitudinally in unison, thereby to swing said linkages.

5. A wheelchair lift as defined in claim 1 in which said arms are straight bars, and are disposed in vertically spaced relation in a common plane.

6. A lift mountable in a vehicle adjacent an access opening thereof, for use in moving an object such as a wheelchair to and from a generally horizontal bed of the vehicle, comprising:

a pair of parallelogram linkages each having a base link mountable in the vehicle adjacent the access opening, two side-by-side elongated arms pivotally mounted on said base link for swinging about spaced, parallel axes between upright positions in the vehicle and outwardly extending, lowered positions, and an end link pivotally mounted on the ends of said arms opposite said base link;

said linkages being spaced apart for mounting in the vehicle for swinging in substantially parallel planes;

a platform for holding the object;

means connecting one edge portion of said platform to both of said end links and holding the platform in a preselected angular position on said end links to maintain the platform generally parallel to said bed during swinging of said linkages and to move said one edge along an arc passing close to the end of the bed at the access opening;

and drive means for selectively swinging said linkages to said upright position, said lowered position, and an intermediate position in which said platform is level with the bed with said one edge adjacent the end thereof, including a reversible electric motor and operating circuitry therefor, first and second manual actuating switches for operating said motor from outside the vehicle and from inside the vehicle, a third manual switch mounted adjacent said platform for movement therewith and for operation by a person on the platform, and switch means responsive to movement of said platform to said intermediate position from either direction for overriding said third switch and stopping the platform in said intermediate position.

7. A lift as defined in claim 6 in which said connecting means connect said platform to said end links for upward pivotal movement from said preselected angular position about an axis extending along, and spaced above, said one edge, for folding of said platform upwardly into a storage position when said arms are in the upright positions, while preventing downward pivoting of the platform from said preselected angular position, and further including cam means in said vehicle and follower means adjacent said one edge, for forcing said one edge downwardly as said arms approach said upright position, thereby to fold the platform automatically to said storage position.

8. A lift mountable in a vehicle adjacent an access opening thereof, for use in moving an object such as a wheelchair to and from a generally horizontal bed of the vehicle, comprising:

a pair of parallelogram linkages each having a base link mountable in the vehicle adjacent the access opening, two side-by-side elongated arms pivotally mounted on said base link for swinging about spaced, parallel axes between upright positions in the vehicle and outwardly extending, lowered positions, and an end link pivotally mounted on the ends of said arms opposite said base link;

said linkages being spaced apart for mounting in the vehicle for swinging in substantially parallel planes;

a platform for holding the object;

two posts extending from said end links down to said platform;

a pivot connecting the lower end portion of each post to said platform adjacent a front corner thereof, for tilting of the platform about an axis disposed above, and extending along, a front edge of the platform, and holding said platform for movement of said front edge along an arc passing close to the end of the bed at the access opening, and beyond the end of the bed, into the vehicle;

means for preventing downward tilting of said platform from a generally horizontal position, but permitting upward tilting into a storage position in which the rear edge of the platform is adjacent said posts;

drive means for selectively swinging the linkages, in unison, to said upright position, said lowered position, and an intermediate position in which said platform is level with the bed with said front edge adjacent, but spaced from, the end thereof;

means on said platform and said linkages for tilting said platform to said storage position automatically as an incident to movement of said linkages to said upright positions, comprising at least one set of cam and follower elements including a follower on said platform adjacent said front edge, and a cam on one of said base links inside the vehicle positioned to engage said follower and cam the latter downwardly as said linkages move into said upright positions.

9. A lift mountable in a vehicle adjacent an access opening thereof, for use in moving an object such as a wheelchair to and from a generally horizontal bed of the vehicle, comprising:

a pair of parallelogram linkages each having a base link mountable in the vehicle adjacent the access opening, two side-by-side elongated arms pivotally mounted on said base link for swinging about spaced, parallel axes between upright positions in the vehicle and outwardly extending, lowered positions, and an end link pivotally mounted on the ends of said arms opposite said base link;

said linkages being spaced apart for mounting in the vehicle for swinging in substantially parallel planes;

a platform for holding the object;

two posts extending from said end links down to said platform;

a pivot connecting the lower end portion of each post to said platform adjacent a front corner thereof, for tilting of the platform about an axis disposed above, and extending along, a front edge of the platform, and holding said platform for movement of said front edge along an arc passing close to the end of the bed at the access opening, and beyond the end of the bed, into the vehicle;

means for preventing downward tilting of said platform from a generally horizontal position, but permitting upward tilting into a storage position in which the rear edge of the platform is adjacent said posts;

drive means for selectively swinging the linkages, in unison, to said upright position, said lowered positions; and an intermediate position in which said platform is level with the bed with said front edge adjacent, but spaced from, the end thereof, said drive means including two sprockets rotatably supported in the vehicle adjacent said access opening above the bed thereof, a chain for each of said sprockets having one end portion extending from the sprocket outwardly over one of the linkages, means connecting said chains to said linkages, means for driving said sprockets to feed said chains back and forth and swing said linkages between said positions;

means for tilting said platform to said storage position automatically as said linkages move to said upright positions and including means stopping inward movement of said platform as said linkages move to said upright positions, and means, including said chains, operating to tilt the platform to said storage position after inward movement of said platform is stopped.

10. In a wheelchair lift device mounted in an opening of a vehicle for selectively moving a wheelchair to the bed of the vehicle from the ground adjacent the vehicle and to the ground from the bed of the vehicle, the combination comprising

two base structures rigidly mounted to the vehicle, one of each of said structures located adjacent opposite sides of the opening of the vehicle so as to not interfere with entry or egress through said opening,

two straight members, each pivotally mounted at one of its ends to spaced points on each of said base structures for arcuate parallel movement about the pivotal mounts between an upright position in the vehicle to an outwardly extending lowered position,

two straight end link members, each pivotally attached to the ends of one pair of said straight members at their ends opposite said base structures,

a movable horizontally arranged platform for receiving the wheelchair and occupant,

means connecting one edge portion of said platform to both of said end link members and for holding the platform in a substantially horizontal plane during the arcuate parallel movement of the two pairs of straight members,

drive means comprising a reversible electrical motor for selectively moving said straight members through said arcuate parallel movement,

means for selectively causing said platform to rotate about one edge to a tilted, stored position within said vehicle when said pairs of straight members are in their upright position in the vehicle, and,

electrical switches selectively operable to determine the extent and direction of movement of said straight members and said platform and the

direction of rotation of said motor.

11. The wheelchair lift device of claim 10, wherein the platform is pivotally connected to said end link members.

12. A lift mountable in a vehicle adjacent an access opening thereof, for use in moving an object such as a wheelchair to and from a generally horizontal bed of the vehicle, comprising:

a pair of parallelogram linkages each having a base link mountable in the vehicle adjacent the access opening, two elongated arms pivotally mounted on said base link for swinging about spaced, parallel axes between upright positions in the vehicle and outwardly extending, lowered positions, and an end link pivotally mounted on the ends of said arms opposite said base link;

said linkages being spaced apart for mounting in the vehicle for swinging in substantially parallel planes;

a platform for holding the object;

means pivotally connecting one edge portion of said platform to both of said end links for moving said one edge along an arc passing close to the end of the bed at the access opening;

drive means for selectively swinging the arms of said linkages from said lowered positions to said upright positions and back and further coupled for tilting the platform into a vertical storage position about an axis generally along the one edge of the platform after the elongated arms of said linkages have reached the upright position;

control means for actuating said drive means and for stopping said linkages in each direction of movement with said platform in an intermediate position level with the bed, for movement of a wheelchair into and out of the vehicle; and

means for preventing downward tilting of said platform from a preselected angular position, but permitting upward tilting into the storage position.