| 摘要 |
A straight-type torsion spring, put together from the two ends, which ends can rotate relative to each other against the force of the torsion spring, where the torsion spring 5 comprises at least four identical torsion rods, which, in the horizontal plane, are delimited by one another along the whole of their length, thereby exploiting the relatively large angle of rotation of the dimensionally small torsion rods, combined with the full rotational force of the torsion spring rods, which torsion spring rods are each rotated in a screw- like manner when the spring is activated. An adjustable fixing device for a chair, preferably an office chair, comprising a torsion spring of the above-defined type, a frame for the seat 1, a frame for the backrest 2 and a fastening plate 3, a tilt lever 9, which is fastened in a tube, the other end of which is fastened in the other end of the torsion spring 5, whilst the upper end of the lever 9 is joined by a hinge joint to the front part of the frame 1 of the seat, the rear part of which is joined by a hinge joint to the frame 2 of the backrest of the seat, to the rear end of which frame the backrest of the seat is fastened, and whilst the front part of the frame 2 of the backrest is joined by a hinge joint to the plate 3, the position of which hinge joint 12 is adjustable, and thereby allows adjustment of the angle of the frame for the backrest of the seat. <IMAGE>
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