Pneudraulic shock absorber

Claim 1

A pneudraulic shock absorber comprising, in combination: a. a cylinder having an axis and two axially spaced end walls and enclosing a sealed cavity axially extending between said end walls, one of said end walls being annular; b. a piston assembly including a piston rod member axially passing through said annular end wall in sealing, movable engagement, and a piston member fastened to said piston rod member in said cavity and axially dividing the cavity into a first compartment and a second compartment; c. a body of liquid in said cavity; d. a body of highly compressed gas filling the remainder of said cavity, the amount of said liquid being such that an interface of said gas and of said liquid approximately bisects the axial length of said cavity in the normal operating position of said shock absorber in which said axis extends vertically, said annular end wall bounds said first compartment, and is upwardly spaced from the other end wall bounding said second compartment; e. guide means axially guiding said piston member for movement through said interface between a first terminal position in which a substantial portion of said liquid and substantially the entire body of said gas is contained in said first compartment, and said second compartment holds the remainder of said liquid, and a second terminal position in which at least a substantial portion of said body of gas and substantially the entire body of liquid is contained in said second compartment, when said shock absorber is in said normal operating position; and f. an annular member of resilient material coaxially mounted in said second compartment adjacent said other end wall and formed with a central aperture axially open toward and said piston assembly, 1. said piston assembly having a radially extending annular face abuttingly engaged by said annular member in said first terminal position of said piston member, 2. said piston assembly including a plunger portion centered in said annular face and projecting from the Same toward said other end wall, said plunger portion being received in said aperture in said first terminal position of the piston member, 3. said piston assembly being formed with a plurality of conduits connecting said compartments, a first one of said conduits having an inlet orifice in said annular face, and an additional conduit having an inlet orifice in said plunger portion and axially spaced from the inlet orifice of said first conduit toward said other end wall, said inlet orifices being sealed sequentially by said annular member during movement of said piston member into said first terminal position, 4. said first conduit and said additional conduit having respective discharge orifice means for discharging jets of fluid into said first compartment in respective directions transverse to each other when said piston rod member moves inward of said cavity.