US 4,303,231 AGranted

Cylinder-and-piston rod device

AssigneeStabilus GmbH

InventorsHermann Reuschenbach, Winfried Wirges, Rolf Langanke

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Abstract

In the illustrative embodiments disclosed, a pressurized cylinder-and-piston rod device, such as a gas spring, includes structure for releasably retaining the piston rod at a terminal position within the cylinder against the fluid pressure tending to expel it. Provision is also made for the fluid pressure to aid in further withdrawing the piston rod into the cylinder after the retaining structure has been engaged.

Claims25

Dependent claims

A cylinder-and-piston rod device, comprising:

(a) a cylinder having a longitudinal axis and defining a sealed cavity therein;
(b) first and second guiding and sealing units provided at first and second ends, respectively, of said cavity;
(c) a piston rod extending axially into said cavity through said first guiding and sealing unit and being axially movable relative thereto between a first terminal position, in which said piston rod extends into said cavity to a minimum extent, and a second terminal position, in which said piston rod extends into said cavity to a maximum extent;
(d) a pressurized fluid in said cavity;
(e) a plunger member extending axially into said cavity through said second guiding and sealing member and being axially movable relative thereto, the axially outer end of said plunger member being exposed to a lower pressure than the pressure of said pressurized fluid in said cavity;
(f) releasably-engageable retaining means carried in part by said plunger member and in part by said piston rod for, when engaged, holding said piston rod against movement towards said first terminal position by the force exerted on said piston rod by said pressurized fluid and, when disengaged, permitting such movement of said piston rod towards said first terminal position;
(g) blocking means carried in part by said plunger member and in part by said cylinder for blocking movement of said plunger member axially outward of said cavity in the direction of said second terminal position when said retaining means are disengaged;
and
(h) releasing means carried by at least one of said piston rod, said plunger member and said cylinder for releasing said blocking means to permit said axially outward movement of said plunger member when said retaining means are engaged, whereby the force exerted on said plunger member by said pressurezed fluid at least partially compensates for said force exerted on said piston rod.

6 more elements

Dependencies are inferred from the claim text.

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Abstract

A cylinder-and-piston rod device, comprising:

(a) a cylinder having a longitudinal axis and defining a sealed cavity therein;
(b) first and second guiding and sealing units provided at first and second ends, respectively, of said cavity;
(c) a piston rod extending axially into said cavity through said first guiding and sealing unit and being axially movable relative thereto between a first terminal position, in which said piston rod extends into said cavity to a minimum extent, and a second terminal position, in which said piston rod extends into said cavity to a maximum extent;
(d) a pressurized fluid in said cavity;
(e) a plunger member extending axially into said cavity through said second guiding and sealing member and being axially movable relative thereto, the axially outer end of said plunger member being exposed to a lower pressure than the pressure of said pressurized fluid in said cavity;
(f) releasably-engageable retaining means carried in part by said plunger member and in part by said piston rod for, when engaged, holding said piston rod against movement towards said first terminal position by the force exerted on said piston rod by said pressurized fluid and, when disengaged, permitting such movement of said piston rod towards said first terminal position;
(g) blocking means carried in part by said plunger member and in part by said cylinder for blocking movement of said plunger member axially outward of said cavity in the direction of said second terminal position when said retaining means are disengaged;
and
(h) releasing means carried by at least one of said piston rod, said plunger member and said cylinder for releasing said blocking means to permit said axially outward movement of said plunger member when said retaining means are engaged, whereby the force exerted on said plunger member by said pressurezed fluid at least partially compensates for said force exerted on said piston rod.

6 more elements