Lever arm shock absorber

Hydraulic shock absorbers, invented by Ralph Peo in 1930, appeared as a development to replace the previous friction disks.

With a viscous device using hydraulic oil, the resistance force increased with speed, so providing better damping for larger suspension bumps.

A lever arm was attached to the axle and inside the cylinder, this rotated a spindle carrying a vane or paddle.

[note 1] This type of shock absorber had a large cast body containing a cylinder and pistons attached to a similar spindle and lever arm.

The upper wishbone could conveniently also be used as the lever of the shock absorber, reducing the mass and bulk of the suspension, and also avoiding at least one ball joint.

About the only area where lever arm shock absorbers still are actively used is tank suspensions,[citation needed] where their compact size and unique geometry allow them to be easily integrated with the suspension's torsion bars, and the massive tank chassis acting as a one huge heatsink alleviates the heat dissipation problems.