GB1278921A - Improvements in and relating to vehicle seats - Google Patents

Abstract

1278921 Resiliently mounted seats UNIVERSAL OIL PRODUCTS CO 4 Dec 1970 [1 Jan 1970] 66/70 Heading A4U A vehicle seat 10, mounted for vertical movement relative to a base 11 by scissor linkages 12, at each side of the seat, is urged upwardly by one or more hydropneumatic springs 21 each comprising a floating piston 30 which divides a cylinder 26 into a gas-filled, e.g., nitrogen, chamber 33 and an oil-filled chamber 31 in which a drive piston 27 is movable by a piston rod 28, the chamber 31 being connected to an annular chamber 32 by one or more restricted openings 34 for leakage of oil to provide a damping action. Movable forward pivots, for the linkages are formed by rollers 17, 18 in guides 19, stops in the guides determining the up-stop position of the seat, shown in full lines in Fig. 1. The piston rod is pivoted to a lever 22 which is pivoted at 23 to the seat and has a roller 24 moving in a guide 25 in the base part, and the cylinder 21 is coupled to the seat by a screwed shaft 35 rotated by a knob 38 in a nut 37 on the seat to vary the preload in the spring to suit the weight of the user. In modifications, leakage through the opening 34 is controlled by a valve, two or more reservoir chambers are formed in the wall of the cylinder and are connectible to the gas chamber by a slide valve to vary the volume into which the gas can be compressed and hence the spring rate, the slide valve being moved by a lever adjusted manually relatively to a rack, or automatically in response to the load through a control member directly connected to the floating piston or to a spring-urged cap fitting over the closed end of the cylinder. In further modifications, the height of the ride position of the seat is adjustable independently of the weight of the user, by altering the position of the drive piston in the oil-filled chamber by bleeding oil from the main oil space through a manually-operated coaxial valve in the drive piston into a reservoir within the piston rod; or, as shown in Fig. 7a, hydropneumatic springs 68, extending along the base plate 61, are connected at their forward ends to screw adjustment 69 for varying the preload in the springs, the rearward ends of the springs being pivoted to coupling arms 71 suspended from a fixed horizontal shaft 72 and inter-connected by a yoke 73, rollers 75 supported by plates 74 welded to linkages 63<SP>1</SP> bearing on the arms 71 to impart forward pivotal movement to the lower ends thereof to compress the springs on downward movement of the seat.