Hydropneumatic damping device

Claim 1

In a hydropneumatic damping device comprising (a) an inner cylinder (10) having an axis and two ends, namely a first end and a second end, (b) a central cavity (22) defined within said inner cylinder (10) between said two ends, (c) an outer container (12) surrounding said inner cylinder (10), said outer container (12) having first and second ends adjacent said first and second ends of said inner cylinder (10), respectively, (d) an annular cavity (24) defined between said inner cylinder (10) and said outer container (12), (e) first and second closure means (16, 14) closing said first and second ends of said cylinder (10) and said container (12), respectively, (f) piston rod passage means through the first ones (16) of said closure means, (g) fluid passage means (32) between said central cavity (22) and said annular cavity (24) adjacent the second ones (14) of said closure means, (h) first fluid throttling means (34) associated to said fluid passage means (32), (i) a piston rod (20) axially extending through said piston rod passage means and into said central cavity (22), (k) a piston unit (26) mounted on said piston rod (20) within said central cavity (22) and defining two working chambers (22a, 22b) within said cavity (22), a first working chamber (22a) adjacent said first closure means (16) and a second working chamber (22b) adjacent said second closure means (14), (l) fluid connecting means (28) connecting said two working chambers (22a, 22b) across said piston unit (26), (m) second fluid throttling means (30) associated to said fluid connecting means (28), (n) a body of liquid at least within the central one (22) of said cavities, (o) a body of gas within said annular cavity (24), said first closure means comprising (aa) a cavity-closing unit (16) surrounding said piston rod (20) and having an axially inner end (16a) adjacent said first working chamber (22a) and an axially outer end, (bb) securing means (12a) provided on said container (12) adjacent the first end thereof for axially securing said cavity-closing unit (16) with respect to said first end of said cylinder (10), (cc) a sealing unit (42) engaging said piston rod (20) and having an outer side exposed to atmosphere and an inner side adjacent said cavities (22, 24) and axially outward of the axially inner end (16a) of said cavity-closing unit (16), (dd) venting passage means (38, 46, 44, 50, 56, 52, 54) between said first working chamber (22a) and said annular cavity (24) extending across said cavity-closing unit (16) on the inner side of said sealing unit (42), (ee) check valve means (16c, 48, 40c) associated to said venting passage means (38, 46, 44, 50, 56, 52, 54) permitting gas residues to flow from said first working chamber (22a) towards said annular cavity (24) and preventing reverse flow, said check valve means (16c, 48, 40c) comprising an annular check valve member (48) in frictional sliding engagement with said piston rod (20) for axial movement with said piston rod (20) towards a sealing position during inward movement of said piston rod (20) and towards an opening position during outward movement of said piston rod (20), first (16c) and second (40c) abutment means being provided for defining said sealing position and said opening position of said annular check valve member (48), respectively, the improvement comprising: at least said second abutment means (40c) being axially secured with respect to said cavity-closing unit (16) by supporting means separate from said cavity-closing unit (16) and fixed with respect to said outer container.