Patent Application
20100164268
The invention refers to a standing wheelchair with a chassis frame to which two drive wheels and at least one steerable wheel are connected, equipped with an uplift unit with a height adjustable seat, a backrest and at least one pivotable foot support.
This type of wheelchair is known from CA 2 458 122 A1 or DE 199 12 830. The constant seated position of the user leads to degradation of bodily functions over long periods of time, such as reduced movement of the lower extremities, deceleration of intestinal activity and the impairment of blood circulation. Sitting also increases the risk of decubitus ulcers. A standing wheelchair aids in reducing these consequences through changes in body position, up to a standing position, which reduces the degradation of bodily functions. The movable seat surface is mounted on a chassis frame with backrest and foot supports. The correct adjustment to the anatomical requirements of the user is a very important criterion for comfort, which the wheelchair offers. Through this, the relation of seat depth and lower leg as well as upper leg to the position of the footrest is determined using the body measurements of the user. In accordance with the dimensions provided, a standing wheelchair is selected from the standard manufacturer program and produced.
User specific manufactured wheelchairs often provide unsatisfactory comfort for small and large people, because the standardized sizes of the standing wheelchairs are based on average body sizes. Often, the lack of adjustment is only indirectly perceived by the user. Friction movement between the body and the seat or an overly strong surface pressure from the kneepads can lead to decubitus ulcers in a short period of usage time. If the seat is adjusted, the angle of the seat is changed in the known wheelchairs, which is uncomfortable.
Standing wheelchairs offer the user the option to participate in sports activities. Thus the user can play golf, for example. In these cases it is particularly important that the wheelchair offer a high degree of stability in the upright position. Thus there is a requirement that the foot supports stand on the floor in the upright position and are supported by it. The backrest must be parallel to the seat and the golfer must have sufficient freedom of movement (turning of the upper body) in order to be able to swing a club.
In such a case, standing wheelchairs are often kept at the ready at golf courses and used by various users. Wheelchairs designed for people of average size can be used by a range of disabled persons only under great loss of comfort, because the seat height is not optimally adjustable.
From CA 2 458 092, an adjustable wheelchair is known. The seat depth can be changed by an adjustable backrest. The backrest is telescoping and connected to the lower chassis of the seat. The telescoping rods are not particularly functional in practical use. In order to guarantee stability, low tolerances are required. Frequent adjustment leads to wear and tear. The bilateral telescoping rods under the seat can tilt toward each other. The backrest is then not straight in relation to the seat and secure uplift of the wheelchair is not possible. Telescoping rods also collect dirt, which is unavoidable during sports activities.
EP 1 412 278 A1 publishes a wheelchair, in which the seat is adjustable in height via a jointed parallelogram, which is pivotable. With the change of the seat height, the position of the seat in the direction of travel is also changed. According to the configuration of the parallelogram, the seat is repositioned either forward or backward when in motion.
Starting with this problem, the standing wheelchair described at the beginning should be improved so that the seat height is adjustable, without changing the angle of the seat or the distance of the foot supports to the ground, as it remains constant regardless of the seat height.
For the solution to this problem, a generic standing wheelchair is proposed, which is characterized in that the seat is supported on a top longitudinal track connected to the seat with a front hinge point, and a lower longitudinal track with front and back hinge points as well as two guides attached to the front and back hinge points forming a parallelogram. The parallelogram is movable with a hub unit for adjustment of the seat height, without significant changes to the relative position of the longitudinal tracks.
By movement of the hinge parallelogram upward and back, the seat height can be changed without changing the angle of the seat to the backrest. Geometric changes can be counteracted if necessary with steering guides. The foot support can be completely removed from the height adjustment and its movement controlled by the uplift kinematics.
For this, the hub unit functions preferably with a longitudinal strut attached at its front end to the front hinge point of the lower longitudinal track and at its back end by hinge point to the chassis and with a steering strut attached at the front end via a hinge with the upper longitudinal track and at the back end via a hinge attached to the chassis.
The steering strut and the longitudinal strut, which are attached to the chassis, push the front part of the seat and frame (on which the seat is positioned) upward in parallel position, so that there is no sinking of the front section. This only changes the relative position of the seat to the chassis. When raising the seat, this only tilts slightly backward.
It is advantageous if the front hinge point of the upper longitudinal track, the hinge point of the longitudinal strut attached to the chassis, the front hinge point of the steering strut and the back hinge point of the steering strut form a jointed parallelogram.
It is particularly advantageous, if the seat is continually adjustable. For this a spindle can be used. This is then particularly advantageous when the spindle is self-locking.
Because both of the jointed parallelograms are situated to either side of the seat, two hub units can also be attached.
If the back ends of the longitudinal tracks have a slot in them, in which the backrest is attached at its lower ends to be movable, the seat depth is also adjustable, so that an optimal seat position can be achieved by the user.
A slot configuration is very robust and resistant to collection of dirt.
If the backrest is adjustable and securable in the slots via slide blocks, low tolerances can be maintained. The slide blocks offer the option of stageless adjustment of the seat depth, canting of the backrest is ruled out, so that the seat and backrest are able to pivot even under rough conditions. Preferably, every slide block is attached to a plate, which is connected with the backrest via hinges. These plates can be attached to each other via a hinge handle, so that the handles clasp the seat during adjustment of the backrest, and aid in sliding the backrest into the slots.
It is advantageous if the longitudinal tracks have recesses parallel to the slots, into which one of the locking pins connected to the backrest can be inserted. The locking pins can be located on the grip elements. The recesses offer the advantage, with the locking pins, that the backrest can be fixed in place before the slide blocks are screwed into the slots. They also offer the advantage that the backrest is also held in place, if the screws loosen.
The recesses are preferably situated at regular intervals, whereby a grid is realizable for the backrest. Instead of recesses, bore holes can also be used.
On the back ends, the longitudinal tracks can also be attached together via a strap.
With the aid of a drawing, the design example of the invention can be more closely described.
It shows:
The wheelchair consists of the chassis 29 with the uplift unit 33 attached, the drive wheels 30 and both steerable front wheels 31. The uplift unit 33 has a seat 3, a backrest 7 and a foot support 32. Via an actuator 28, the uplift unit 33 can be rotated. The seat 3 then moves to a vertical position. The backrest 7 retains its vertical position and is located parallel to the seat 3. Simultaneously with the tilting of the seat 3, the foot support 32 sink and is supported on the ground in the extended position of the uplift unit 31. To lift the seat 3 and the backrest 7, the actuator 28 moves the cross strut 22 and the hinge point 21 along a longitudinal track.
Under the seat 3, there are two longitudinal tracks 1, 2. The upper track 1 is attached to the seat 3 and has a front hinge point 10 and a back hinge point 11. The lower track 2 has a front hinge point 12 and a back hinge point 13. Via the hinge points 10, 12; 11, 13, the upper track 1 and the lower track 2 are attached to each other, whereby a parallelogram is formed. That is, the distance C from the front hinge points 10,12 is identical to distance D of the back hinge points 11,13 and distance A of hinge points 10,11 of the upper track 1 is identical to distance B of the hinge points 12, 13 of the lower track 2.
The longitudinal tracks 1, 2 have a longitudinal slot 1a, 2a in the back area which is closed on the peripheral side. Slide blocks 5a, 6a which are attached to plates 5, 6 (see
In order to adjust the backrest 7 and the seat depth X, the faceplates 5b, 6b connected via screws 5′, 6′ with plates 5, 6 are loosened, both grip units 16 are separated so that the locking pins 9, 9′ come out of the recesses 1b, 2b and the backrest 7 can then be moved forward or backward. The locking pins are inserted in to the relevant recesses 1b, 2b and screws 5′, 6′ are tightened again.
As shown in
The lower part of the backrest 7 connected with plates 5, 6 via a hinge can be formed in one piece with the backrest 7 or a triangular guide 18. By changing the distance D of hinge points 11, 13 and B of 12, 13, the angle a of the backrest 7 is adjusted relative to the seat 3.
In the figures one can see that the seat 3 is positioned on a parallelogram made up of the upper longitudinal track 1, the lower longitudinal track 2, as well as the guides 4, 19 connecting the front and back hinge points. For adjustment of the height of the seat 3, the hinge parallelogram 10-12, 11-13 is pushed up and down using a self-locking spindle 26. Working together with the spindle 26 are the longitudinal strut 27, which is connected at its front end to the lower longitudinal track 2 in hinge point 12 and is located on the chassis with its back end in hinge point 25, as well as the steering strut 24, its lower end also being located on the chassis 29 and its upper end located on the upper longitudinal track 1 in another hinge point 23. The balance strut 8 is located above the hinge plate 19 attached to its front end in connection with hinge point 12 of the lower track 2 and the hinge point 10 of the upper track 1. On its lower end, the balance strut 8 is attached to the chassis 29 with a hinge plate. The hinge plate 19 and the balance strut 8 have the task of holding the hinge point 12 in position during raising and lowering of the seat 3. In this way, the backrest angle a only changes slightly during the up and downward motion of the seat 3.
The foot support 32 is attached via bilateral hinged vertical struts 34 and is dropped vertically by the actuator 28 with the uplift of the seat 3. The bell crank 35, which is attached via the guide 36 to the actuator 28, changes the rotational movement into a vertical movement.
The length of the spindle 26 is adjustable using a non-represented tool. Instead of the spindle 26, a pneumatic spring or electrical linear adjustment may be used as a hub unit.
Through a change in the position of the hinge point 21, the angle of the seat 3 can be influenced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 038 030.1 | Aug 2005 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DE2006/001360 | 8/3/2006 | WO | 00 | 2/8/2008 |
