A WHEELCHAIR

Abstract: A wheelchair includes two side frames (1L and 1R) consisting of respective lower frame parts (1'L and 1'R) and respective upper frame parts (1"L and 1"R). Each side frame has transverse, horizontal, tilt pivot axis (3) between its upper and lower parts. Forwards of each axis (3) is a tilt adjustment device (4) acting between the lower frame part and the upper frame part. Each device (4) may take the form of a gas spring, an electric motor or a screw device. The lower frame parts (1'L and 1'R) are linked by a pair of shear braces (5L and 5R) with a vertical pivot axis (6) in the centre. The upper frame parts (1"L and 1"R) are linked by one or more pairs of transverse braces (8L and 8R) with a pivot axis (9) in the centre. Seat plates are fixedly mounted at the top surfaces of the respective braces (8L and 8R). The seat plates can form the whole or part of the seat, or can be the basis for other seating elements, such as cushions and seat shells. A sling-form backrest is provided between the upper frame parts. When the tilt adjustment device (4) is operated, the upper frame parts and thus the seat and the backrest turn around the pivot axles (3) and give a desired tilt position. Independently of the tilt position, the wheelchair can be folded. This folding wheelchair has the advantage of having an occupant-operable tilt adjustment and is particularly advantageous in that the occupant can operate the tilt adjustment while seated in the wheelchair.

Description: A Wheelchair The invention concerns a foldable wheelchair. The GB 15 61 694 describes a perambulator in which the child can be transported in both lying and seated position. The perambulator comprises a frame to which the wheels and the hand grips are attached, and a seat arrangement pivotally mounted on the frame and comprising a foldable seat covering. The tilt angle is adjusted manually and fixed by means of screws. The entire perambulator is foldable, whereby it is, however, not described how the components connecting the frame are designed to facilitate folding. This construction is not transferable to wheelchairs due to stability requirements. In addition, the seat frame must be placed in upright position or removed entirely before folding the perambulator. The GB 20 29 33 40 describes a wheelchair comprising a motor drive and especially suited for severely disabled patients who can only move their fingers. The wheelchair is not foldable, so that no information on the details of the frame construction is given. The wheels and an upper frame with a seat which is tiltable around a horizontal axis are mounted on the lower frame. A mechanical, hydraulic or pneumatic adjustment mechanism is provided between the two frames for this purpose. The GB 21 26 537 A describes a foldable wheelchair comprising two lateral frames to which the wheels are attached. Movable connection of the two frames is effected by means of two intersecting connection braces in the central area of the frame which can be moved scissor-like around a common folding axis in their intersection point. The tilt of the seat is not adjustable. 2 The problem of the invention is to increase the use options of foldable wheelchairs whilst simultaneously assuring easier handling. According to the present invention, a wheelchair is provided which comprises lower frame means and upper frame means tiltable backwards and forwards relative to said lower frame means, ground wheels mounted on said lower frame means, and seating and backrest means carried by said upper frame means, whereby said frame means are foldable inwards transversely of the wheelchair, substantially irrespective of the tilt position of said upper frame means. Owing to the present invention, it is possible to provide a transversely folding wheelchair whereof the seating and backrest means are tiltable backwards and forwards. Although the seating and backrest means may include a rigid backrest readily removable to permit inward folding of the wheelchair, the backrest is preferably flexible. The advantage of the invention is that the tilt of the seat can be retained during folding of the wheelchair. It is therefore not necessary to first bring the tilt into a base position and then reset the tilt in optimal position for the patient again after unfolding the wheelchair. This significantly eases wheelchair handling. Due to the tilt adjustment of the seat, the foldable wheelchair is also suited for patients who require or prefer a tilted seat position. The wheelchair according to the invention combines the advantages of being foldable and hence transportable with high comfort due to seat adjustability. The upper frame means advantageously comprise at least one pair of foldable transverse braces. During folding of the wheelchair these braces are moved upwards. During unfolding of the wheelchair the braces are preferably brought automatically into a horizontal stable position. The joint axis of these transverse braces preferably extends in direction parallel with the seat and in longitudinal direction of the wheelchair. The seat and backrest advantageously comprise a pair of seat panels also arranged foldably. The seat plates can form the whole or part of the seat or can act as the base for other seating elements, such as cushions and seat shells. The pair of transverse pairs is preferably designed as a single piece and connected by a pressure hinge. The pressure hinge comprises at least one stop and at least one abutment, which abut on each other in unfolded state when the transverse braces lie in one plane. This defines the final position and prevents bending. Since the seat plates are fastened on the upper side of the transverse braces, the transverse braces are also subject to pressure from above. In unfolded state the wheelchair is stabilised by the transverse braces and the seat plates, so that no additional arrest means are needed. A further embodiment provides that the transverse braces possess at least one stop in the pivot area on the upper frame portion, which cooperates with at least one abutment of the upper frame portion when the wheelchair is in unfolded state. This also stabilises the unfolded state of the wheelchair. These stops and abutments can be provided alone or in combination with the pressure hinge. According to a further embodiment, the juxtaposed brace pairs connecting the upper frame are replaced by individual elements. Tilt members are mounted preferably pivotally on the lower side of the seat plates on the upper frame portion. These tilt members advantageously comprise at least one stop in the pivot area of the frame, whereby said stop cooperates with at least one abutment of the frame when the wheelchair is in unfolded state. 4 Advantageously a pressure hinge which connects the two seat plates is attached on the lower side of the two seat plates. This independent pressure hinge can be used together with the pivot members fitted with abutments and stops or with pivot members which do not comprise such fixing and stabilising means. The pivot members according to the invention can conversely also be used together with a conventional hinge. In this embodiment, the connection of the upper frames is effected by the seat plates. The advantage of this embodiment consists in the fact that the width of the seat surface is not defined by the transverse braces and can therefore be adjusted across the full width of the seat plates. The wheelchair can be fitted with seat plates of differential width, whereby adaptation to the needs of the patient is facilitated. The lower frame means preferably also comprise at least one lower pair of transverse braces pivotally connected with each other. The joint axis preferably extends in vertical direction. The fact that the joint axis of the transverse braces of the lower frame and the joint axis of the transverse braces of the upper frame substantially rest on each other in vertical direction, contributes to stabilisation of the wheelchair in unfolded state. The full length of this lower brace pair is preferably greater than the width of the wheelchair in unfolded state defined by the upper transverse braces resp. the width of the seat plates. The two braces of the brace pair always form an angle < 180° in unfolded state, so that the width of the wheelchair is not limited by these braces. This development is especially advantageous if the wheelchair is to be fitted with seat plates of differential width. Preferably, transverse, horizontal pivot means is provided that interconnects said upper frame means and said lower frame means, so that said upper frame means is tiltable about a horizontal axis relative to said lower frame means. A tilt adjustment mechanism is located forwards from said pivot means, so that an 5 occupant of the wheelchair is able to cause said tilt adjustment mechanism to operate to change the degree of tilt of the upper frame means relative to the lower frame means. The tilt adjustment mechanism can also be located backwards from said pivot means. In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a fragmentary top plan view of a wheelchair, Figure 2 is a perspective view of the wheelchair but with seat plates and a backrest removed for clarity of illustration, Figure 3a,b a side plan view and a perspective view of the seat braces, Figure 4a, b a side plan view and a perspective view of seat brace means according to another embodiment. Referring to the drawings, the wheelchair includes two side frames 1 (namely, a left-hand frame IL and a right-hand frame 1R) consisting of respective lower frame parts 1' (namely, a left-hand lower frame part l'L and a right-hand lower frame part l'R) and respective upper frame parts 1 " (namely, a left-hand upper frame part 1"L and a right-hand upper frame part 1"R). Each side frame 1 has a transverse, horizontal, tilt pivot axis 3 between its upper and lower parts 1 " and 1 ' . Forwards of each axis 3 is a tilt adjustment device 4 acting between the lower frame part 1' and the upper frame part 1". Each mechanism 4 may take the form of a gas spring or an electric motor (giving continuous adjustability) or of a screw or clamp device, such being manually remotely operable, for example by means of a press button, by the occupant of the wheelchair, or may be a screw device (giving continuous operability). The lower frame parts l'L and l'R are linked by a pair of shear braces 5, consisting of a left-hand brace 5L and a right-hand brace 6 5R with a vertical pivot axis 6 in the centre. The outer ends of the shear braces 5L and 5R are connected to the lower frame parts l'L and l'R, respectively, by way of vertical pivot axes 7. The upper frame parts 1 "L and 1 "R are linked by one or more pairs of seat braces 8, each pair consisting of a left-hand seat brace 8L and a right-hand seat brace 8R with a pivot axis 9 in the centre, the pivot axle 9 being oriented parallelly to the seat surface proper. The or each pair of seat braces 8 is pivotally connected to the upper frame parts 1 "L and 1 "R by respective pivot axes 10 parallel to the or each pivot axle 9. A left-hand seat plate 11L and a right-hand seat plate 11R are fixedly mounted at the top surfaces of the braces 8L and 8R, respectively. It is alternatively possible to provide a pair of integral seat plate units in place of the braces 8 and the plates 11. The seat plates can from the whole or part of the seat, or can be the basis for other seating elements, such as cushions and seat shells. A sling-form backrest 12 is provided between the upper frame parts 1 " . When the tilt adjustment mechanism 4 is operated, the upper frame parts 1 " turn around the pivot axis 3 and give a desired tilt position. Independently of the tilt position, the wheelchair can be folded. During the folding (or unfolding) operation, three movements occur simultaneously. These are [as indicated by the arrows (a) in Figure 2] the left and right frames IL and 1R moved towards (or away from) each other, [as indicated by the arrow (b) in Figure 2] the pair of shear braces 5 fold so that their centre axis 6 moves longitudinally of the wheelchair - depending upon the design of the wheelchair, the axis 6 moves either forwards as shown for folding (or rearwards for unfolding), or rearwards for folding (or forwards for unfolding) - and [as indicated by the arrow (c) in Figure 2] the or each pair of seat braces 8 folds upwards (or downwards), until their end positions are reached. The end condition of the folded wheelchair is determined by contacting surfaces of the left-hand and right-hand shear braces 5L and 5R, or contacting surfaces of the left-hand and right-hand seat braces 8L and 8R. The end condition of the unfolded wheelchair is given by abutment surfaces on the seat braces 8 or on the seat plates 11. 7 The folding wheelchair described with reference to the drawings has the advantage of having an occupant-operable tilt adjustment and is particularly advantageous in that the occupant can operate the tilt adjustment while seated in the wheelchair. In Figs. 3a and 3b the transverse braces 8L,8R are shown in enlargement. Fig. 3a shows the transverse brace pair in unfolded state; Fig. 3b shows the same in folded state. The transverse braces 8L and 8R respectively comprise a pivot hook 13L and 13R on their outer ends, whereby said hook pivotally attaches the transverse braces 8L and 8R on the upper frame portion 1"L and 1"R. The two seat plates 11L and 11R not shown in the Figure are mounted on the surfaces 14L and 14R of the transverse braces 8L and 8R. The transverse braces 8L and 8R are connected with each other by an integrated pressure hinge 15 comprising the pivot axis 9. The pressure hinge 15 is formed in such manner that the position of the two transverse braces 8L,8R shown in Fig. 3a is stable. The pressure hinge 15 prevents bending of the transverse brace pair 8L,8R even under pressure. For this purpose, several stops and abutments are provided, as shown in Fig. 3b. Each transverse brace 8L and 8R comprises stop surfaces 16a,b and 17a,b in the hinge area and corresponding abutment surfaces 18a,b and 19a,b. When the two transverse braces 8L,8R are converted into extended, unfolded state as shown in Fig. 3a, the stop surfaces 16a,b abut on the abutment surfaces 18a,b. The same applies to stop surfaces 17a,b which cooperate with the abutment surfaces 19a,b. In this way, a stable position of the transverse braces 8L and 8R is ensured without additional auxiliary means, whereby the whole wheelchair is simultaneously stabilized. Figs. 4a and 4b show a further embodiment. Whereas in Figs 3a and 3b the pivot hooks 13L and 13R and the pressure hinge 15 are integral components of the transverse braces 8L and 8R, the embodiment shown in Figs. 4a and 4b consists 8 of individual components. Two short pivot members 20L and 20R, which consist of the pivot hooks 13L and 13R and two short profile portions 23L and 23R on whose upper side the corresponding seat plates 11L and 11R are mounted, are pivoted on the upper frame portions 1"L and 1"R. The pressure hinge 15' is also an independent component and, in similar manner as the pressure hinge 15, comprises corresponding stop surfaces 16a,b, 17a,b and abutment surfaces 18a,b, 19a,b. The two pressure plates 11L and 11R are also mounted on the upper side of the pressure hinge 15'. The width between the frame portions 1"L and 1"R can be fixed across the width of the seat plates 11L and 11R because the pivot members 20L and 20R are not connected with the independent pressure hinge 15" The wheelchair can hereby by easily readjusted for wider or narrower seat plates. List of Reference Numerals IL left hand frame 1R right hand frame l'L lower frame part l'R lower frame part 1"L upper frame part 1"R upper frame part 3 tilt pivot axis tilt adjustment device pair of shear braces L left hand brace R right hand brace vertical pivot axis vertical pivot axis pair of transverse braces L left hand transverse brace R right hand transverse brace pivot axis 10 pivot axis 11L left hand seat plate 11R right hand seat plate 12 sling-form backrest 13L pivot hook 13R pivot hook 14L surface 14R surface 15 pressure hinge 15' pressure hinge 16a,b stop surface 17a,b stop surface 10 a,b abutment surface a,b abutment surface L pivot member R pivot member stop surface abutment surface L profile portion R profile portion

Claims: 11 Claims: 1. A wheelchair comprising lower frame means (l'L, l 'R, 5L, 5R) and upper frame means (1"L, 1"R, 8L, 8R) tiltable backwards and forwards relative to said lower frame means (l'L, l'R, 5L, 5R), ground wheels mounted on said lower frame means, and seating and backrest means (11L, 11R, 12) carried by said upper frame means (1"L, 1"R, 8L, 8R), wherein said frame means (l'L, l'R, 1"L, 1"R, 5L, 5R, 8L, 8R) are foldable inwards transversely of the wheelchair, substantially irrespective of the tilt position of said upper frame means. 2. A wheelchair according to claim 1, wherein said seating and backrest means (12) include a flexible backrest. 3. A wheelchair according to claim 1 or 2, wherein said upper frame means includes at least one pair of transverse braces (8L, 8R) pivotally interconnected end-to-end and foldable around the pivotal interconnection. 4. A wheelchair according to claim 3, wherein said pivotal interconnection of said pair of transverse braces (8L, 8R) has a pivot axis (9) being oriented in parallel with the seat surface. 5. Wheelchair according to one of claims 3 or 4, wherein said pair of transverse braces (8L,8R) is provided as a single piece and connected by a pressure hinge (15). 6. Wheelchair according to claim 5, wherein said transverse braces (8L,8R) comprise at least one stop in the pivot area and said stop cooperates with at least one abutment of the upper frame portion (1"L,1"R) when the wheelchair is in unfolded state. 12 7. A wheelchair according to any preceding claim, wherein said seating and backrest means include a pair of seat plates (11R, 11R) pivotally interconnected edge-to-edge and foldable around their pivotal interconnection. 8. Wheelchair according to one of claims 3 to 7, wherein said seat plates (11L,11R) are mounted on the transverse braces (8L.8R). 9. Wheelchair according to one of claims 1 and 2, wherein pivot members (20L,20R) which pivotally rest on the upper frame portion (1"L,1"R) are mounted on the lower side of the seat plates (11L,11R). 10. Wheelchair according to claim 9, wherein said pivot members (20L,20R) comprise a stop (21) in the pivot area of the upper frame portion, which cooperates with an abutment (22) of the frame portion (1"L,1"R) when the wheelchair is in unfolded state. 11. Wheelchair according to one of claims 1, 2, 9 or 10, wherein a pressure hinge (15) which connects the two seat plates (11L,11R) is mounted on the lower side of the seat plates (11L,11R). 12. A wheelchair according to any preceding claim, wherein said lower frame means include at least one pair of transverse braces (5) pivotally interconnected end-to-end and foldable around their pivotal interconnection. 13. A wheelchair according to claim 5, wherein said pivotal interconnection of said pair of transverse braces (5) of said lower frame means has a substantially vertical pivot axis (6). 13 14. A wheelchair according to any preceding claim, wherein said pivot axes (6 and 9) are disposed perpendicularly to each other if the upper frame means are not tilted. 15. A wheelchair according to any preceding claim, wherein transverse, horizontal pivot means (3) interconnect said upper frame means (1"L, PR, 8L, 8R) and said lower frame means (l'L, l'R, 5L, 5R), so that said upper frame means (1"L, 1"R, 8L, 8R) is tiltable around a horizontal axis (3) relative to said lower frame means (l'L, l'R, 5L, 5R), and a tilt adjustment mechanism (4) is located forwards from said pivot means (3), an occupant of the wheelchair being able to cause said tilt adjustment mechanism (4) to operate to change the degree of tilt of the upper frame (IL, 1R, 8L, 8R) means relative to the lower frame means (l'L, l'R, 5L, 5R).

Inventors: LINDENKAMP HORST, LINDENKAMP, HORST
Applicants: INVACARE DEUTSCHLAND GMBH, LINDENKAMP HORST, LINDENKAMP, HORST
Application year: 1999
Main classification: A61G5
IPC codes: A61G5