GB1281624A - Height adjustment apparatus for an elevatable portion of an article of furniture - Google Patents

Abstract

1281624 Seat adjustments CRAMER INDUSTRIES Inc 18 Aug 1970 39789/70 Heading A4J [Also in Division E2] A telescopically adjustable seat support comprises a closed cylinder 13 which is filled with hydraulic fluid 24 and rotates in a supporting barrel 10, a movement damping piston 29 in the cylinder, an elongated collet tube 44 sleeved on to the top part of the cylinder 13 and slideable on it, and an outer cylinder 57 secured to the seat and sleeved on to the collet tube, and a releasable clamp gripping the inner cylinder to support the seat. The top end of the supporting barrel 10 is welded to a stop ring 9 in a seating 8 in the base 4 of the seat, and the cylinder 13 is rotatably supported by ball bearings 17 at its bottom, removal of the cylinder from the barrel being prevented by bolt 20. A threaded top-plug 26 guides piston-rod 28 of piston 29 which has axial bores 34 allowing vertical movement of the piston. The piston-rod is secured to a cap 46 on the collet to move with it. A check-valve 37 in one passage, increases the upward damping. The lower end of the collet is slotted at 52 to provide ramped fingers 54 which can grip the outer surface of the cylinder 13 when a ring 56 in a recess 59 in the outer cylinder 57 is forced downwardly on to ramps 55. By this means the collet 44 and outer cylinder 57 are supported on the inner cylinder 13. Upward movement of lever 61 moves cross arm 62 and cap 46 of the collet downwardly and so moves the collet tube downwardly with respect to outer cylinder 57 to free the ring from the ramp and so release the gripping fingers and so allow vertical movement of the seat. This movement is assisted by springs 33 which counterbalance the weight of the seat &c. Downward movement of the lever locks the seat in vertical position. Weight on the seat augments the gripping at ramp 55 by pressing the outer cylinder 57 downwards.