Adjustable hydraulic damper

Claim 1

A telescopic shock absorber of the kind comprising a cylinder containing hydraulic fluid, a double-ended piston with ports therethrough slidably housed in said cylinder, a piston rod threaded through said piston and fast with it, and flexible discshaped valves normally seated against each piston end in port obturating position and liftable therefrom by deflection upon exertion of hydraulic pressure through said piston ports, wherein the improvement comprises two resiliently deformable annular flanges of cambered shape at rest, fitted on said piston rod on opposite sides of said piston beyond said respective valves and having each a central portion firmly pressing a corresponding central portion of the respective valve against the respective piston end to prevent deflection of said valve central portion, said cambered flanges having further each a peripheral portion bent away from the respective piston end and a corresponding peripheral portion of the respective valve to allow deflection of said valve peripheral portion, said flange central portion and said flange peripheral portion being connected to each other through a deflection line about which said valve peripheral portion flexes, and two bell-shaped abutment members independently adjustably positionable on said piston rod on opposite sides of said piston beyond said respective cambered flanges and axially displaceable relatively to said piston rod towards or away from the respective piston eNds, said abutment members respectively engaging the peripheral portion of said cambered flanges to flatten out the same and displace said deflection line thereof radially outwards upon said abutment members being driven closer to said piston, whereby lift of said disc shaped valves is correspondingly restrained.