CHAIR ADJUSTMENT DEVICE

Abstract: The invention relates to an adjustment device for a chair, especially of the type adapted for use by handicapped persons, comprising a seat (2), which is by means of the adjustment device (1) adjustable to desired angular positions. The seat (2) can be tilted or tipped around a turning shaft (3) located below the seat and the tilting or tipping movement can be in a stepless and accurate fashion controlled by the aid of a control spindle (4), the one end (5) of which is rotatably mounted in the frame (6) of the chair (2). Its other end (7) is by means of a nut member (8) at the front or rear portion of the seat (2) and at a predetermined distance from the turning shaft (3) mounted for rotation and for displacement in the longitudinal direction of the spindle (4).

Description: CHAIR ADJUSTMENT DEVICE The present invention relates to an adjustment device for chairs, especially chairs adapted to be used by handi- capped persons, comprising a seat, which by means of the adjustment device can be set in different angular positions. The main surface plane of the seat can from a horizontal position be inclined both forwards and backwards for the purpose of achieving an adjusted position matching the intended use of the chair- Prior art chairs of similar type intended for use by persons suffering from different handicaps, especially spasticity, exhibit seats, which can be brought into different angular positions with the aid of various piston-cylinder arrangements. In this type of adjustment devices the piston movement in the cylinder is controlled by means of a manually operated valve and the device functions against a spring means continuously striving to tilt the seat into a position inclined forwards or backwards in response to the structural arrangement of the device. The most usual arrangement is that the structure with the aid of the spring member holds the seat in a forwards inclined position, which is altered when the control cylinder device is opened by means of a lever and a person sits down on the seat. The angular position is then changed to an outer end position, somewhat inclined backwards. By actuation of the control lever for the cylinder device the seat can be brought into a desired position yielding a comfortable seating, the seat being then by the spring automatically tilted forwards into the position corresponding to release of the control lever for the piston-cylinder device. However, this technical solution has proved inconvenient to persons suffering from certain types of handicap, particularly spasticity. If the control lever is not handled correctly the result may be that the person can actually fall out from the chair. The object of the present invention is to provide an adjustment device eliminating those drawbacks by offering a chair device permitting the seat to be in a stepless and simple manner brought into a desired position without any risk of actuation of its control device resulting in the seat tilting forwards to its extreme angular position where it is inclined forwards. This has been achieved by means of an adjustment device constituted by a threaded rod or adjustment spindle rotatable by means of a wheel and the threads of which have a pitch, which in combination with the rotation speed of the control wheel deter- mines the position adjustment speed of the seat. Thanks to the present invention there has been provided an adjustment device, which in an excellent way satisfies its purpose and by means of which the handicapped person can himself very easily adjust the chair seat to the desired position. An additional function of the device according to the invention is that, during and after the adjustment proper, the seat is always automatically maintained locked in exactly the latest selected position. A preferred embodiment of the invention will now be described in greater detail, reference being made to the attached drawings, in which Fig. 1 is a diagrammatic partial lateral view of the adjustment device according to the invention mounted below a chair seat, Fig. 2 is a diagrammatic partial end view of the adjust- ment device shown in Fig. 1 and Fig. 3 illustrates how the adjustment device shown in Figs 1 and 2 can be mounted in the frame of a chair. As appears most clearly from Fig. 1, an adjustment device 1 according to the present invention is mounted below a chair seat 2, the main surface plane of which can be inclined both forwards and backwards for the purpose of selecting a comfortable adjusted position for the seat 2. Stated in other words, the seat 2 is tiltable or pivotable around a turning shaft 3 , which is mounted below the seat 2. According to the exemplifying embodiment this turning shaft 3 is located approximately centrally below the seat and extends in the transversal direction thereof. The adjustment device 1 consists of a control spindle 4, the one end 5 of which is rotatably mounted in the frame 6 of the chair 2 and the other end 7 of which is rotatably and, as counted in the longitudinal direction of the spindle 4 , displaceably mounted by means of a nut member 8 in the front portion 9 of the seat 2 at a predetermined distance from the turning shaft 3. The opposite, second end 7 of the spindle 4 exhibits a wheel 10, by means of which the spindle 4 can be manually rotated either clockwise or counterclockwise in response to the desired inclination of the seat 2. The one end 5 of the spindle 4 is rotatably mounted in the chair frame 6 by means of a frame bearing 11, in which the end 5 of the spindle 4 is rotatable. The bearing member 11 is in its turn rotatably mounted transversely to the longitudinal direction of the spindle 4. The other end 7 of the spindle 4 exhibits an outer and an inner adjustment nut 12 and 13, respectively, which by rotation can be displaced along the spindle 4 to a predetermined distance between themselves. This distance defines a movement distance along the spindle 4, within which, for the purpose of adjusting the inclination of the seat 2, a seat bearing member 14 supported by the seat 2 can be displaced in a stepless manner in response to rotation of the spind- le 4. The seat bearing member 14 is rotatably supported by two pin bearing members 15 and 16, which it surrounds and which are mounted in fork supports 18 and 19 projecting from the bottom surface 17 of the seat 2. The fork supports 18 and 19 are by screws 20 and 21 held in fixed positions on the pin bearing members 15 and 16. In a similar fashion the frame bearing 11 exhibits two pins 22 and 23, which are rotatably mounted in the chair frame 6 and held secured by the screws 24 and 25. The control wheel 10 on the spindle 4 does at its circumference have a handle 26 conveniently rotatably mounted to facilitate the manual rotation of the wheel 10 during adjustment of the seat 2. The nuts 12 and 13 can be set in desired positions defining the ends of the seat adjustment range corresponding to the intended use of the chair equipped with an adjustment device according to the invention.

Claims: Claims 1. An adjustment device for a chair, especially for handicapped persons, comprising a seat (2) , which by means of the device (1) is adjustable between different angular positions, the main surface plane of the seat (2) being, from a horizontal position, adjustable to both forwards and backwards inclined positions permitting the selection of a correct seating position matching the intended use of the chair, characterized in that the seat (2) can be tilted or tipped around a turning shaft (3) located below said seat, the tilting or tipping movement thus produced being controllable in a stepless and precise manner by means of a control spindle (4) , the one end (5) of which is stationary but rotatably attached to the frame (6) of the chair (2) , while the other end (7) of said spindle (4) has a nut member (8) pivotably connected to a front or rear portion (9) of said seat (2) at a predetermined distance from said turning shaft (3) , whereby, upon rota- tion of said spindle (4) , said nut member (8) is displaced in the longitudinal direction of the spindle (4) and thereby produces a positional adjustment of the seat (2) . 2. Device as claimed in claim 1, characterized in that the other end (7) of the spindle (4) at its outer free portion has a control wheel (10) permitting manual rotation of the spindle (4) in the one or the opposite direction in response to the desired inclination of the seat (2). 3. Device as claimed in claim 1, characterized in that the one end (5) of the spindle (4) is rotatably mounted in the frame (6) of the chair (2) by means of a frame bearing (11) , in which the one end (5) of the spindle (4) is rota- tably mounted, the frame bearing (11) being in its turn mounted for rotation transversely to the longitudinal direction of the spindle (4) . 4. Device as claimed in claim 1, characterized in that the other end (7) of the spindle (4) has an outer and an inner adjustable nut (12, 13), which are by rotation movable along the spindle (4) to a predetermined distance between themselves, said distance defining the movement range along the spindle (4) , within which a seat bearing member (14) connected to the seat (2) is movable in stepless fashion during rotation of the spindle (4) for adjustment of the inclination of the seat (2) . 5. Device as claimed in claim 4 , characterized in that the seat bearing member (14) is rotatably supported by two pin bearing members (15, 16) projecting therefrom and mounted in the fork supports (18, 19) projecting from the bottom side (17) of the seat (2) . 6. Device as claimed in claim 2, characterized in that the control wheel (10) at its circumference exhibits a rotatably mounted handle (26) .

Inventors: DU REES STEPHAN, DU REES, STEPHAN
Applicants: MERCADO MEDIC AB, REES STEPHAN DU, DU REES, STEPHAN
Application year: 1998
Main classification: A47C5
IPC codes: A47C1, A61G5