The present invention relates to an improved adjustment structure for varying the capacity of fluid shock absorbers of both the pneumatic and liquid types, and it also relates to improved pneumatic and liquid shock absorbers which provide increased shock absorbing capacities because the pistons therein expand relative to their associated cylinders during operation to add a frictional shock absorbing force to the force due to the action of the fluid therein.
By way of background, in the past needle valves and the like were used to adjust the bleed from shock absorbers to vary their shock absorbing capacity. However, needle valves had a very limited range of operation because the fluid which was being forced out of the shock absorber traveled substantially axially relative to the needle valve. In addition, insofar as known, fluid shock absorbers, both of the liquid and pneumatic types, relied solely on the restriction of movement of fluid to produce a shock absorbing action. Furthermore, pneumatic shock absorbers could only operate in a limited low force range whereas hydraulic shock absorbers could generally only operate in a limited high force range. There was, however, a range between the high force and low force ranges that it was difficult to obtain adequate shock absorption with a relatively low cost, simple shock absorber of the pneumatic type.