COLLAPSIBLE FRAME, PREFERABLY FOR WHEELCHAIRS

Abstract: A collapsible frame, preferably for wheelchairs, including two side portions (1, 2) which are mutually spaced, vertical and substantially parallel in the position of use, between which there is carried a seat and which are movable towards each other to a collapsed state. The frame includes first support means in the form of two U-shaped members (3, 4) which are articulately connected mutually and with said side portions, second support means in the form of crossed struts (10, 11) which are articulately connected with the first support means and side portions, a locking rod (17) articulately attached to the first support means and glidably united with the second support means as well as being adapted for locking said first and second support means in a predetermined position in relation to each other in the position of use.

Description: The present invention relates to a collapsible frame, preferably for wheelchairs, including two substantially parallel side portions arranged vertical and mutually spaced in a position of use, between which there is carried a seat, and which are movable towards each other into a collapsed ,«, position, two support means articulately connected to each other and to said side portions and two support elements articulately connected to the support means and the side portions. Collapsible wheelchairs are known, which are constructed sub¬ stantially as illustrated in the U.S. Patent Specification 2 401 085, and namely include two side portions and crossed struts articulately connecting them, the struts extending from the lower edge of each side portion and towards the upper edge of the opposing side portion. In order to collapse the chair the upper end of said support strut is united with the upper edge of the respective side portion by a link connection. In the wheelchair of the patent specification this link joint consists in that the seat is hinged at the middle, and when the wheelchair is collapsed the seat folds upwards. The disadvant¬ age with such wheelchairs is that they are extended in height when they are collapsed, which results in that the collapsed frame becomes clumsy and voluminous, thus making it difficult to put into such as the back seat or boot of a car. Another already known collapsible frame for a wheelchair is illustrated in the Swedish Patent Specification 161 002. This frame comprises two vertical side portions united with rods, which are also mutually united. This structure is very complicated and requires loosening certain joints for collapsing. The frame further uncludes a strut at its center and which extends along the entire length of the frame, to project out in front of the chair frame when the wheelchair is collapsed. It will be realized that this structure is also to be regarded as complicated for a handicapped person, who is to take the wheelchair in a vehicle, as is often the case. Sports for the handicapped have resulted in that lighter and simpler wheelchairs have been designed. The total weight has been almost f 4 halved for these chairs, which has resulted in that they have not been made collapsible. To compensate this the wheels have been provided with a quick release connection so that they can be rapidly removed from the wheelchair frame, which may then be placed in such as the passenger seat in a vehicle. This restricts the space in the vehicle, and there has been a desire to be able to collapse such frames as well. The object of the present invention is to achieve a collapsible frame, preferably for wheelchairs, in which extension or collapse takes place in a single operation, the side portions, respectively, moving away or towards from each other and where the parts included in the frame are situated substantially within the periphery of the side portions the whole time. A further object of the invention is to achieve a collapsible frame which is reliable and simple in its construction and function. The objects are achieved in accordance with the invention by the frame including a locking rod which is articulately attached to a first support means and glidably, united with a second support means, the rod being adapted to lock them in a predetermined relation to each other in the position of use. Preferred embodiments of the invention have been given the charaberizing features disclosed in the subordinate claims. It has thus been found that the inventive frame results in a reduction of the volume, by collapsing taking place within the side portions. With regard to weight, the inventive frame can be made so that it can be compared to the wheelchairs which are intended to be used in conjunction with sports. A further advantage with the inventive frame is that collapse and extension take place in a single operation, with the aid of the mentioned locking rod. The invention will now be described in detail in the following, with reference to the accompanying drawings illustrating a preferred embodi¬ ment. Fig. 1 is a perspective view of an inventive frame, particularly for a wheelchair. Fig. 2 is a view from above of a collapsed frame. Fig. 3 is a side view of the collapsed frame. Turning now to Fig. 1, there is illustrated a collapsible frame, particularly for wheelchairs. It includes two vertical side portions 1 and 2 which are parallel and mutually spaced in a position of use, these portions preferably comprising tube structures, with each portion forming a rigid lattice. The frame further includes two U-shaped tubular members 3 and 4, the free ends of which are articulately connected to the side portions 1 and 2 by pivot joints 5, 6 and 7, 8, the members also are mutually connected with the aid of a hinged joint 9. The frame further has two struts 10 and 11. One end of the strut 10 is articulately connected to the side portion 1 with the aid of a pivot joint 12 and its other end is articulately connected by a pivot joint 13 to the U-shaped member 4, which is articulately connected to the opposing side portion 2. The second strut 11 is at one end connected by a pivot joint 14 to the other side portion 2, and at its other end is pivotably connected to the opposing U-shaped member 3, which as mentioned is pivotably connected to the side portion 1. A locking head 16 is rotatably united with the first strut 10 at a predetermined place along its length. A locking rod 17 which is adapted glidable in a hole in the locking head 16 is rotatably and articulately united to the hinged joint 9 between the U-shaped member 3 and 4 at one end, and at its other end it is provided with a handle 18 for opening out and collapsing the frame. Alternatively, the locking rod 17 may be rotatably and articulately united with one of the U-shaped members 3 and 4. The frame is illustrated in a collapsed state in Figs. 2 and 3, the U-shaped members 3 and 4 having been taken backwards so that they are substantially parallel to the side portions and within the periphery thereof. The struts, which seen laterally are above each other, have been moved towards each other so that they are also substantially parallel to the side portions. In the collapsed positions, the arms 19 and 20 supporting the back support have been folded forwards and downwards with the aid of articu¬ lations arranged thereon, so that the supporting arms of the back support are substantially parallel to the upper edge of the side portions of the frame. When the frame is to be opened out to the position of use, the side portions are moved away from each other and the handle is pulled forward, so that the U-shaped members are moved to the position illustrated in Fig. 1. There is a locking position on the locking rod 17 in the form of a recess 21, illustrated by dashed lines in Fig. 3. When the recess engages with an unillustrated spring-loaded pin or ball in the locking head 16, the locking rod 17 is locked to the locking head 16 in a predetermined position, which concurs with the opened-out or usable state of the wheelchair. This locking means, comprising the locking head 16 and recess 21 on the locking rod 17, may of course be replaced by some other known locking device. It is however important that the locking means meets the purpose of locking the U-shaped members 3 and 4 and the struts 10 and 11 in a predetermined position in relation to each other in the position of use, so that a stiff frame is formed, comprising two parallel, mutually spaced side portions, which are so stable that they can carry, inter alia, rear wheels 22, 23, front wheels 24, 25 and footrests, illustrated in Fig. 1 by chain-dotted lines, as well as an unillustrated seat carried between the upper longitudinal tube portions of the side portions, and furthermore also support an unillustrated back support between the rods 19 and 20. With the inventive frame there is thus achieved that in its collapsed state the parts, in the form of struts and U-shaped members supporting the side portions, are substantially within the periphery of the side portions, so that the frame between less voluminous that the frames of the prior art becomes less and it will be neither higher nor longer in the collapsed state. Furthermore, the supporting structure consists of few parts, which also contributes to lowering the total weight of the wheelchair in relation to the weight of previously known collapsible wheelchairs. In a further development of the wheelchair in accordance with the invention, both struts 10 and 11 are articulately connected to the locking head 16. A guide arm is then arranged between the locking head 16 and the U-shaped members 3 and 4, for defining in the position of use the distance between the U-shaped members and the locking head, so that automatic locking of the included parts is afforded when pulling out the rod 17 by its handle. Within the scope of the invention, further struts may be arranged on either side of the locking head. Thus, in a modified embodiment, one strut may be arranged above the locking head and another below it. Furthermore, in a still further modified embodiment, the frame may include four struts, of which two extend mutually parallel on either side of the locking head from one side portion and two extend mutually parallel on either side of the locking head from the other side portion. On the drawings there is illustrated a preferred embodiment, where the struts and the U-shaped members are adapted such that the locking rod is directed horisontally forwards. It will be understood that the struts and the U-shaped member can be oriented in any desiredposition between the vertical side portions, within the scope of the invention. For example, when the frame is manufactured so that it is turned 90° in relation to the embodiment illustrated on the drawings, with the locking rod directed vertically upwards, there is obtained a frame with room for a seat between the struts. In this case the locking rod must either be collapsible, or placed so that in the position of use it does not project forward into the space between the struts where the seat is. Although on the drawings all the included parts are made from tubing or rods, it will be understood that these can be exchanged for other known structures. For example, the frame can be built up from metal plates or other suitable material. The U-shaped members may also be replaced by upper and lower rods, which are united by an elongate, vertical hinged joint. The invention can of course be modified further within the scope of the following claims.

Claims: CLAIMS 1. A collapsible frame, preferably for wheelchairs, including two substantially parallel side portions arranged vertical, and mutually spaced in a position of use, between which there is carried a seat, and which are movable towards each other into a collapsed state; two support means articulately connected mutually and to said side portions, and two support elements articulately connected to the support means and the side portions, characterized by a locking rod articulately attached to one or both of the support means and glidably united with one αf the support elements, the rod being adapted to lock the support means and support elements in a pre¬ determined relationship to each other in the position of use. 2. The collapsible frame as claimed in claim 1, characterized in that said support means comprises two substantially U-shaped members (3, 4) with the ends of their limbs articulately connected to one of the side portions (1, 2) such that said members in the collapsed state are substantially parallel to the side portions within the periphery of the latter, and that the webs of the U-shaped members are hingedly connected to each other. 3. The collapsible frame as claimed in claim 1 or 2, characterized in that said support elements comprise at least two struts (10, 11) each jointed to a U-shaped member (3, 4) and its opposing side portion (2, 1), said locking rod (17) being glidably united with at least one strut. 4. The collapsible frame as claimed in claim 1 or 2, characterized in that said support elements comprise at least a first strut articulately connected to one U-shaped member and its opposing side portion, and at least a second strut articulately connected to the second side portion and the first strut, said locking rod being glidably united with at least one strut. 5. The collapsible frame as claimed in any of claims 1-4, character¬ ized in that said locking rod (17) is taken through a hole in a locking head (16) carried by one or both struts (10, 11), the rod being provided with means (21) for locking the rod against movement through said locking head in the position of use. 6. The collapsible frame as claimed in claim 5, characterized in that said means is a recess (21) in said locking rod (17), said recess being adapted for engaging with a springbiased pin or ball in the locking head (16) in the position of use, the locking rod being adapted rotatable for releasing said engagement between pin or ball and the recess for collapsing the frame.

Inventors: BILLUNG BJOERN, WIDERCRANTZ NILS, BILLUNG, BJOERN, WIDERCRANTZ, NILS
Applicants: BILLUNG BJOERN, WIDERCRANTZ NILS, BILLUNG, BJOERN, WIDERCRANTZ, NILS
Application year: 1984
Main classification: A61G5
IPC codes: A61G5