Driving around today, you may take for granted that you don’t feel the impact of every small bump or rock in the road, but these little impacts caused passengers in early cars quite a bit of discomfort. All vehicles available on the market today are equipped with shock absorbers. This little tool was invented by vehicle manufactures in order to improve driving stability and increase passenger comfort. Designed to absorb shock impulses, it converts the kinetic energy of an impact into a different type of energy. This energy is most typically turned into heat and then dissipated.
Car manufacturers worked to dampen shock for passengers as soon as vehicles were available to the public. The first shock dampening tools widely used on cars were called leaf springs. The tool used a spring between mechanical leaves that dampened shock impact. A review of them in 1912 pointed out that they were largely unreliable as a shock dampening mechanism and did not operate well when wet.
The Telesco Shock Absorber was the first hydraulic dampener to go into mass production. First unveiled to the public at the 1912 Olympia Motor Show, it was constructed of a telescopic unit with a spring inside. It also contained oil and an internal valve, allowing oil to absorb shock in the rebounding direction. The Telesco Shock Absorber was made to fit at the rear end of a leaf spring so that it could be easily applied to existing vehicles. The concern that rose from this was that the damping was not applied to the main leaf spring, but only to the spring inside the telescopic unit.
The Birth of Modern Shock Absorbers
Maurice Houdaille patented an original concept in 1908 that addressed the main leaf spring movement. The first production hydraulic dampers were likely based on these designs by Houdaille. They utilized a lever arm that controlled hydraulically damped vanes inside the unit. The biggest advantage that this new concept provided was that it had the ability to resist sudden movement while simultaneously allowing for slow movement. The problem facing rotary friction dampers was that they often became stuck and then offered the same resistance across all speeds of movement.
Although this idea was the birth of today’s shock absorber, it was not widely commercialized until the end of World War I. These lever arm shock absorbers were most notably implemented as standard equipment on the 1927 Ford Model A.
Types of Shock Absorbers
Today, vehicles are equipped with either a twin-tube or mono-tube shock absorber, although there are some variations on these models.
Twin-tube shock absorbers are equipped with two cylindrical tubes. There is a compression valve at the base of the device. When a piston is forced up or down on the road, hydraulic fluid pumps between chambers in the piston and the valves, absorbing the energy of impact and converting it into heat.
Mono-tube shock absorbers have only one of the cylindrical tubes, yet they do have two pistons. Due to only having one tube, this design lacks directionality and can be mounted on a vehicle either way. Because of this, the mono-tube shock was considered to be a breakthrough advancement when it was first invented in the 1950s.