Lever arm shock absorber

Rotary vane shock absorber, 1935

Lever arm shock absorbers were the first form of hydraulic shock absorber or damper used for car suspension. They appeared in the 1930s and were most commonly used in the 1950s and 1960s, but were replaced by telescopic shock absorbers in the 1970s.[1] One of the earliest patents for a hydraulic lever arm shock absorber was awarded in 1925 to Georges de Ram,[2] who was already an established maker of friction disk shock absorbers.

Hydraulic shock absorbers, invented by Ralph Peo in 1930, appeared as a development to replace the previous friction disks.[1] These had, at best, provided a constant damping force, no matter what the size or speed of the suspension movement. With a viscous device using hydraulic oil, the resistance force increased with speed, so providing better damping for larger suspension bumps.

  1. ^ a b Setright, L. J. K. (1976). "Suspension". In Ian Ward (ed.). Anatomy of the Motor Car. Orbis. pp. 166–167. ISBN 0-85613-230-6.
  2. ^ US 1529878, de Ram, Georges Henri Ernest, "Shock absorber for the suspension arrangements of vehicles", published 17 March 1925