Damper 11 - History
For a long time, it was not unusual that advertising brochures made a point of mentioning the hydraulic-telescopic shock absorbers in cars. The question that then arises, is what did a car look like, without shock absorbers with a piston, a cylinder and an oil filling? Which were the forerunners of today's shock absorbers? Did the old-timers perhaps, have no shock absorbers at all?
The successors to the carriage era only managed without shock absorbers, if they were equipped with multiple-leaf springing. When compressing, friction was generated by the individual spring-leaves. All the others, (e.g., those with torsion-springs) inclined, more or less, to see-sawing. This effect can only be efficiently countered by using friction dampers. Basically, they are built up similar to multi-disc dry clutches. Alternatively, steel discs with pads are placed one on top of the other. The package of steel discs is firmly connected to the external cylinder which is mounted onto the car body. The pads are firmly connected to the inner cylinder which, through a rod-linkage, is connected to the suspension. One spring, with an adjustable pre-tension, holds the rib-package together. The damping effect depends on the spring tension and the friction coefficient of the pads.
This is the reason, why friction dampers were replaced by hydraulic shock absorbers. They required too much servicing and repair, if this was not done, the handling characteristics were quite an adventure. Driving with rapidly dertiorating damper efficiency means being afraid, that on every bump in the road, the vehicle could see-saw so strongly that it becomes uncontrollable and no longer reacts to the steering. Friction dampers were still being installed until about 1960 (e.g., in the Citroen 2CV).