DE3431723C1 - Foldable wheelchair - Google Patents

Abstract

There is described a wheelchair whose rigid, foldable seat half-shells (1) are made of a very thin, springy, perforated material and are divided in their back region into transverse strips (10 to 15) forming troughs in the unfolded state due to their excess length which minimise the high seating pressure under the ischial tuberosities. The longitudinal centre (5) of the seat half-shells (1) is supported by the central bar of the foldable wheelchair frame. A foam cushioning of constant density and thickness rests on the seat half-shells (1), the cushioning being folded together with the wheelchair. This wheelchair has a very uniform seating pressure and permits very small folding width. <IMAGE>

Description

A preferred embodiment of the invention is set out below Hand of fig. 1 to 5 described in more detail. F i g. 1 a half of Seat shell in the folded state of the wheelchair from the side without seat cushion, or viewed from above with the wheelchair unfolded. F i g. 2 shows a cross section the seat shell with seat cushion when the wheelchair is folded.

F i g. 3 shows the cross section of a seat half-shell with a seat cushion when unfolded and loaded by the buttocks. F i g. 4 shows the longitudinal section a seat half-shell in the unfolded and loaded state and FIG. 5 shows a A perspective view of the wheelchair frame without wheels.

In Fig. list shows a seat half-shell (1) on the side edge (2) The seat clamps (3) are attached to the top spar of the side frame (4) grip the wheelchair. On the longitudinal center (5) of both seat half-shells (1) is a Rod hinge (6) attached, which connects to the mirror image, but not Manufactures shown seat half-shell. Holes distributed over the entire surface (7, 8) ensure the unhindered passage of air and moisture. Also have the seat half-shells (1) in their rear area, transverse slots (9) that emerge from them Cut out the horizontal strips (10 to 15). There are short ones on the horizontal stripes (10 to 15) Hinges (16) attached in such a way that their hinge axes overhang the longitudinal center (5) of the seat half-shells (1) and the axis of the bar hinge (6) own.

These protrusions create depressions when the wheelchair is unfolded (17) of the seat half-shells (1) and are dimensioned according to the desired depth of the recess. The position and length of the transverse slots (9), however, determine the position and size of the Depressions (17) within the surfaces of the seat half-shells (1).

In order to prevent the seat half-shells (1) from being in their Longitudinal middle (5) reach their lowest point, is a middle spar (18) for support intended. Like F i g. 5 shows, the central spar (18) can be part of the foldable Wheelchair frame (4, 18, 19), which consists of the two side frames (4), the central spar (18) and the four transverse brackets (19), the transverse bracket (19) on the central spar (18) and hinged to the side frame (4). At Mittenholm you can too a legrest (not shown) can be attached. This is when folding the Wheelchair pulled back at the same time with the central spar (18), whereby the The folding length of the wheelchair is automatically reduced.

A recess (20) on the central spar (18) is advantageous to reduce the pressure Keep it small under the tailbone, especially with the backrest tilted backwards.

The two-part piece lies on the seat half-shells (1), but in the longitudinal center sewn seat cushions (21). It can be placed loosely and thus easily exchangeable because it is laterally through the side edges (2) of the seat half-shells (1) and the side frame (4) of the wheelchair is limited and front and rear by the Transverse edges (22, 23) of the seat half-shells (1). As in Fig. 3 and F i g. 4 shown is, the troughs (17) of the seat half-shells (1) are designed so that the seat cushion (21) when the buttocks and thighs (24) are subjected to almost the same compression everywhere and thereby creates an even seat pressure.

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Claims (2)

Claims: 1. Foldable wheelchair with foldable seat, the two fixed, perforated and articulated in the longitudinal center padded half-shells, characterized in that a) the half-shells (1) made of a very thin and spring-hard material and b) in the rear area by starting from the longitudinal center (5) and only partially severing the half-shells (1) Transverse slits (9) have formed transverse strips (10 to 15), which c) the longitudinal center (5) protrude so different that they unfolded due to their excess length in the Create state troughs (17) in the half-shells (1) and d) the half-shells (1) themselves in the unfolded state on one in the longitudinal center (5) and the form support the center spar (18) adapted to the troughs (17). 2. Foldable wheelchair according to claim 1, characterized in that a legrest is attached to the central spar (18) 3. Foldable wheelchair according to Claim 1 or 2, characterized in that a loose, two-part seat cushion (21) constant density and thickness is used, through the side edges (2) and the transverse edges (22, 23) of the half-shells (1) are fixed in them. The invention relates to a foldable wheelchair according to the preamble of claim 1. Such a wheelchair is known from DE-OS 31 45568. This wheelchair has firm, level, but padded seat shells that remove the unwanted side Avoid pressure on the buttocks and thighs with the hanging belt used as a seat conventional wheelchairs is inevitable. However, it is firm, level, padded When sitting, the pressure is by no means evenly distributed over the seat: In the area the ischial tuberosity, there are stark differences in pressure, such as B. by B. Fowles: Skin tolerance factors of prolonged sitting, Bulletin of Prosthetics Research, Spring 1965, Wheelchair Conference, Minneapolis, USA. These pressure differences can be reduced by increasing the thickness of the padding, but increased the folding width of the wheelchair in an undesirable way. In addition, thick seat cushions are unsuitable for good air and Water vapor permeability, which ensures a good microclimate. Finally could you can also remove the seat cushion before folding the wheelchair, but then you would be making it difficult to use. Of course, the aim is to increase the pressure on the seat as evenly as possible to distribute the seat, not without controversy: In DE-AS with 17 274 and in DE-OS 2603312 are z. B. wheelchairs are described, the seats of which are uneven Have pressure distribution. Most of the time, however, the medical side requires to equalize the seat pressure and special under the ischial tuberosities to be kept as small as possible in order to avoid seat damage to the surrounding skin are unavoidable at high pressure and long exposure time, see z. B. W. D. Seiler and H. B. Stähelin: Dekubitus, Hospitalis, 52nd year, Solothurn 1982. The invention has therefore set itself the task of reducing the seat pressure of a wheelchair and especially in the area of the ischial tuberosities to reduce without increasing the padding thickness. This task is carried out by the characterizing features of claim 1 solved. The invention assumes that the contour lines of a seat cushion loaded by the buttocks and thighs are more constant Depict density and thickness at the same time as the lines of the same pressure. The pressure is therefore greatest at the point where the depression (= spring deflection) is largest in the seat cushion. An ideal even seat pressure would be given if the spring deflection would be the same at every point on the seat cushion. Under neglect due to the shear stresses in the seat cushion, an even seat pressure can be achieved, if the seat on which the seat cushion lies is not flat, but rather Has depressions that correspond to the shape of the buttocks and thighs. One of those The shaped seat also increases the folding width of the wheelchair. Therefore, the invention makes use of the fact that the Seat pressure in the longitudinal center of the seat is close to zero. This allows a very thin, spring-hard seat shell that is suspended from the side frame of the wheelchair in Longitudinal center can be supported by a central spar of the wheelchair frame to a Avoid sagging under load. It is also provided that for better Adjustment to the respective shape of the buttocks, the seat shell in its rear area is divided into strips by transverse slots, which are independent of the neighboring strips can adapt to the shape of the buttocks. In addition, these horizontal stripes are somewhat graduated made longer compared to the rest of the seat width, so that they unfolded in the The state of the wheelchair sags more depending on the excess length, with the greatest sag lies below the ischial tuberosity. In this way, the seat of the wheelchair consists of two im folded state plan seat half-shells, from which in the unfolded state form two hollows that adapt to the shape of the buttocks due to their flexibility, however do not generate the side pressure that the seat belts of conventional folding wheelchairs do is peculiar. For the purpose of foldability, the seat half-shells are in the longitudinal center connected in a hinge-like manner and articulated to the side frames on their outer long sides connected to the wheelchair. Because the distance between the ischial tuberosities is practical in humans is constant, a single execution becomes suitable for all adult humans be. Variants of the seat shell are, however, by changing the arrangement and the length of the horizontal stripes possible without much effort. The one lying on the seat shell When loaded, the seat cushion follows the shape of the trough with the effect that its deflection and so the seat pressure is almost the same over the entire seat surface.