Spring suspensions for vehicle seats

Claim 1

A spring suspension for a vehicle seat, the suspension comprising a seat frame, a base frame, a scissor-action linkage arm system interconnecting said seat frame and base frame, the system including two pairs of scissor-action linkage arms spaced apart on a common pivot axis, pivotal connections interconnecting the ends of said arms and said frames to permit the frames to move towards and away from one another, each pivotal connection on one pair of arms being coaxial with a corresponding pivotal connection on the other pair of arms, and a biassing spring connected between parts of the suspension which pivot relatively to one another during relative movement of the frames towards or away from each other to bias the two frames away from one another, all of the pivotal connections between one of said seat and base frames and the adjacent ends of the linkage arms connected to said one frame being displaceable connections extending in a common direction to permit both relative pivotal movement between the linkage arms of each pair and relative translational movement between all the linkage arms and said one frame and a motion limiting resilient coupling, including an anchoring spring of limited expansion and contraction connected between said one frame and one of said displaceable connections to the linkage arm system to permit relatively free fore and aft translational movement along said common direction between the whole linkage arm system and said one frame within the limits of expansion and contraction of the spring thereby reducing the transmission of vibration in said common direction between the base frame and the seat frame.