IL163373A - Wheelchair able to climb and descend stairs - Google Patents

Description

WHEELCHAIR, ABLE TO CLIMB AND DESCEND STAIRS rnrrran ntw^ Background of the Invention Field of the Invention The present invention relates to the field of individual means of transportation, and, more particularly, to vehicles, mainly, wheelchairs able to step over obstacles, for example, to climb and descend stairs.

State of the Art Wheelchairs for transportation of an invalid in accompaniment of a caretaker able to move over stairs and across a level surface are known, for example, model T 06 made by Vimec Co. Italy, models 2000/S and 2000/L made by T.G.R. Co. Italy, and Scalamobil made by Ulrich Alber Co. Germany.

These wheelchairs have driving spiders with running wheels and a mechanism for locking and unlocking of the running wheels provided with its own drive. The use of the drive for the said mechanism makes the wheelchair design cumbersome and insufficiently economical.

A vehicle is known (US Patent 5,653,301) designed to climb and descend stairs and comprising a frame with rear wheels, a lifter for the vertical displacement of the frame, an extendable supplementary support of the frame, and an extendable supplementary prop of the lifter. The lifter is slidably mounted on the longitudinal guide of the frame. The said support and prop interact with the frame and the lifter, respectively, and are intended to periodically support the front portion of the apparatus when climbing or descending the stairs. Specifically, the supplementary support of the frame supports the apparatus when it is not supported by the lifter, and the supplementary prop of the lifter supports the apparatus when it is supported by the lifter. The support and the prop are movable and lockable between the retracted position used for the storage and the adjustable extended position. According to the patent specification, the support and the prop may be extended and retracted manually or with the help of a separate device.

The apparatus may be used for transporting various devices, including wheelchairs for the handicapped, over stairs.

However, the use of the apparatus so designed is not sufficiently feasible, since the manual operation of the supports of the frame and the lifter is impracticable for the occupant, especially, a handicapped one. In this case, the aid of another person is required to extend, retract, adjust and lock the support and the prop on each step, which limits the functional capabilities of the wheelchair and makes its use labor-intensive. The use by the handicapped of special devices for handling the support and the prop is not feasible as, firstly, it complicates considerably the operation of the wheelchair and, secondly, necessitates the development of previously unknown simple and economical devices.

According to US Patent 4790548, the vehicle able to step over obstacles, for example, stair steps, comprises a frame, driving spiders with a bi-directional drive, main running wheels and a means for locking and unlocking these wheels relative to the driving spider. The said means comprises a differential gear driving either the driving spider alone or the wheels set on the spider. When climbing a staircase the spiders begin rotating as soon as the wheels stop rotating having encountered a step riser. The differential gear is also used for descending stairs.

Although this vehicle is essentially free of shortcomings inherent in the previously described arrangements, the use of differential gear in it makes the design cumbersome and insufficiently economical.

Summary of the Invention The object of the present invention is, therefore, the task of simplifying the design of the wheelchair able to step over stairs and to make the wheelchair more economical.

The said and other tasks, for example, to climb and descend on the narrow and spiral staircase, are fulfilled due to the circumstance that the wheelchair comprises a frame with a seat for an occupant and a transverse axle rotatable carrying spiders at its outer ends. Each spider has, at least, three evenly spaced radial legs and sets on the axle with possibility of a turn relative to the axle. A bi-directional drive is provided to rotate the axle with the spiders. Main running wheels are linked with the radial legs of the spider and used for moving the wheelchair both over stairs by means a caretaker and across a level bearing surface by means a caretaker or an occupant. There is a means for locking and unlocking the main running wheels relative to the spider. This means comprises a brake unit fixed on the spider, a projection fixed on the axle, two stops fixed on the spider, limiting the turn of the spider relative to the axle and kinematic unit linking the spider to each main running wheel and providing either for pressing of this wheel to the brake unit by rotating the spider, when the bi-directional drive operates. Said pressing ensures moving of the wheelchair over stairs. Herewith, the spiders are rotated by axle by means interacting of the projections with the stops.

Cutting out of the drive guarantees a moving or stoppage of the wheelchair on a level bearing surface. Herewith, the main running wheels draw away from the brake unit and get at a contact with each other by means kinematic units, the spider is turned and the stop draw away from the stopped projection, because of acting of the wheelchair weight.

Simplest brake unit is a friction drum set on the same axle as a spider. The kinematic unit comprises the radial leg and a traction bar with its first and second end connected by means of pin hinges, respectively, to the free end of the radial leg and the axle of the main running wheel.

There are two auxiliary running wheels used for moving and turning the wheelchair on a level bearing surface. Said auxiliary running wheel linked with the frame and freely rotatable to the axis perpendicular to the seat.

The means for locking and unlocking the main running wheels operates during setting in motion and cutting out of the bi-directional drive. These properties of the said means make the wheelchair design more simple and economical.

Brief Description of the Drawings The essence of the invention is illustrated by drawing wherein: Fig.1 shows schematically the wheelchair according to the present invention. Fig.2 is a view along arrow A in Fig.1 Fig.3 shows unit B in Fig.2.

Fig.4 shows unit C in Fig.l.

Fig.5 shows a sectional view taken along lines D-D of Fig.4.

Fig.6 shows the relative position of the components of the wheelchair while moving upstairs.

Fig.7 shows the relative position of the components of the wheelchair while moving downstairs.

Detailed Description of the Preferred Embodiments of the Invention The wheelchair according to the present invention and its movement over stairs are described below.

The wheelchair comprises frame 1 (Fig.l) with seat 2 for occupant 3, main running wheels 4 used for moving the wheelchair both over stairs 5 and across level bearing surface 6. Transverse axle 7 is set on frame 1. Spiders 8 are put on axle 7 on the both sides of frame 1 with possibility of a turn relative to this axle on bearing 9. This turn is limited by projection 10 fixed on axle 7 and interacting with two stops 11 and 12 fixed on spider 8. Each spider 8 has three evenly spaced radial legs 13. Three main running wheels 4 are linked with spider 8 by a kinematic units. The kinematic unit comprises said radial leg 13 and, besides, traction bar 14 with its first and second end connected by pin hinges 15 and 16 to the free end of radial leg 13 and to axle 17 of running wheel 4, respectively. A brake unit is also put on axle 7, said brake unit being friction drum 18 attached rigidly to spider 8. The kinematic unit, friction drum 18, projection 10 and rests 11, 12, together form a means for locking and unlocking main running wheels 4 relative to spider 8. Embodiments of the present invention are possible wherein the said means for locking and unlocking main running wheels 4 relative spider 8 and/or the brake unit may be designed differently than those described above. Spider 8 is rotated by means of bi-directional electric drive 19 attached to frame 1, powered by storage battery 20. There are two auxiliary running wheels 21 used for moving and turning the wheelchair on a level bearing surface 6. Said auxiliary running wheel linked with the frame 1 and freely rotatable to the axis 22 perpendicular to the seat 2.

Caretaker 23 must to accompany the wheelchair with occupant 3 during the movement over stairs 5 and across level surface 6.

The wheelchair is controlled by means three-position switch 24 (Fig.3). Switch 24 has three positions: "S" - moving or stoppage of the wheelchair on a level bearing surface, I - moving of the wheelchair upstairs, II - moving of the wheelchair downstairs.

In the initial position, when the wheelchair is on level bearing surface 6 (Fig.l) switch 23 is in the "S" position. The wheelchair is supported on surface 6 by main running wheels 4 and wheels 21. Electrical drive 19 is cut out and axle 7 is braked.

A position of the kinematic units, main running wheels 4 and stops 11, 12 are put because of an action of the weight of the wheelchair and occupant 3. Wheels 4 draw away from friction drum 18 by means traction bars 14 and hinges 15, 16 and are put in the position, when the top wheel 4 engages the two bottom wheels 4, spider 8 are put so that stops 11, 12 are drawn away from projection 10 (Fig.l, 4) Moving and turning the wheelchair on level bearing surface 6 are performed by occupant 3 by means rotating of the top wheels 4, or by caretaker 23 (Fig.l).

In order to be moved upstairs (Fig.6) or downstairs (Fig.7) switch 24 is brought from position "S" to position 1 or 11, respectively. At that bi-directional electric drive 19 is set in motion and rotates the spider 8 in the direction of arrow E (Fig.6) or arrow F (Fig.7). Respectively, projection 10 interacts with stop 11 or 12. Since spider 8 is fastened via friction drum 18 to main running wheels 4, the entire assembly "axle 7 -projection 10 - stop 11 or 12 - spider 8 - drum 18 - wheels 4" begins rotating. As a result, the wheelchair moves upstairs or downstairs, accompanied by caretaker 23.

Although the invention has been described and illustrated with certain degree of particularity, it is understood that the present disclosure has only been made by way of example, and that various modifications there may be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter claimed.

Claims (3)

(Claims:

1. Wheelchair, able to climb and descend stairs comprising: - a frame having a seat for an occupant, - an axle connected to the frame, transversely relative to wheelchair, - spiders set on the axle on the both sides of the frame with possibility of a turn relative to the axle, - said driving spiders each having at least three evenly spaced radial legs, - bi-directional drive to rotate the axle with the spiders, - main running wheels linked with the radial legs of the spider and used for moving the wheelchair both over stairs and across a level bearing surface, - a means for locking and unlocking the main running wheels relative to the spider, - the said means comprising a brake unit and a projection fixed on the axle, two stops fixed on the spider and interacting with the projection and a kinematic unit linking the spider with each main running wheel and providing for pressing of these wheels to the brake unit by rotating of the spider, ensuring a movement of the wheelchair over stairs during setting in motion the bi-directional drive, - the said means ensuring a movement of the wheelchair on a level bearing surface during cutting out the bi-directional drive, under acting of the wheelchair's weight drawing to each main running wheel away from the brake unit of the spider turned by the wheels due to kinematic units, getting the wheels in contact with each other and drawing the stop away from the stopped projection, - an auxiliary running wheels used for moving and turning the wheelchair on level bearing surface, - said auxiliary running wheel linked with the frame and freely rotatable to the axis perpendicular to the seat.

2. The wheelchair according to Claim 1, wherein the spider has three radial legs, the brake unit is made as a friction drum set on the same axle as the spider and the kinematic unit comprises a said radial leg and a traction bar with its first and second end connected by means of pin hinges, respectively, to the free end of the radial leg and to the axle of the main running wheel.

3. The wheelchair according to any of Claims 1 to 2 as described above with reference to enclosed specification. Applicants E. Lapatin O. Lapatin