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US 4,457,212 AGranted
Hydraulic ram
AssigneeGewerkschaft Eisenhutte Westfalia
InventorsEberhart Unger, Herbert Heitkamp, Heinz Hessel, Karl-Heinz Plester, Manfred Lagodka
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AssigneeGewerkschaft Eisenhutte Westfalia
InventorsEberhart Unger, Herbert Heitkamp, Heinz Hessel, Karl-Heinz Plester, Manfred Lagodka
Estimating the term…
A hydraulic ram for use in thrust-jacking of tunnel linings comprises a cylindrical outer member, a cylindrical inner member reciprocable within the outer member, and an extension member reciprocable within the inner member. A two-part clamping ring is provided for releasably locking the extension member to the inner member. An auxiliary drive is provided for retracting the extension member rapidly within the inner member. The auxiliary drive may be a mechanical spindle drive, or a hydraulic drive having an auxiliary piston reciprocable within an axial bore formed in the extension member. The clamping ring comprises spring means for urging the parts of the clamping ring in to the closed position, and piston-and-cylinder means for urging the parts of the clamping ring apart, against the biasing force of the spring means, to open the clamping ring.
A hydraulic ram comprising a cylindrical outer member, a cylindrical inner member disposed within the outer member and reciprocable relative thereto, an extension member disposed within the inner member and reciprocable relative thereto, a clamping device for releasably locking the extension member to the inner member, and drive means provided at least partly within the extension member for retracting the extension member rapidly within the inner member.
A hydraulic ram comprising a cylindrical outer member, a cylindrical inner member disposed within the outer member and reciprocable relative thereto, an extension member disposed within the inner member and reciprocable relative thereto, a clamping device for releasably locking the extension member to the inner member, and a spindle drive for retracting the extension member rapidly within the inner member, the spindle drive comprising a spindle motor and a screw-threaded spindle, the spindle being disposed in a screw-threaded bore formed in the extension member, and the spindle being in drivable engagement with the spindle motor.
A hydraulic ram comprising a cylindrical outer member, a cylindrical inner member disposed within the outer member and reciprocable relative thereto, an extension member disposed within the inner member and reciprocable relative thereto, a clamping device for releasably locking the extension member to the inner member, and a hydraulic drive for retracting the extension member rapidly within the inner member, the hydraulic drive comprising an auxiliary piston reciprocable within an axial bore formed in the extension member, the auxiliary piston being connected to the inner member by means of a piston rod, and wherein means are provided for supplying pressurised hydraulic fluid to an annular working chamber defined by that portion of the axial bore on the piston rod side of the auxiliary piston, said working chamber being sealed with respect to a main working chamber provided within the outer member.
In a hydraulic ram comprising a cylindrical outer member, a cylindrical inner member disposed within the outer member and reciprocable relative thereto, an extension member disposed within the inner member and reciprocable relative thereto, a multi-part clamping ring for releasably locking the extension member to the inner member, and drive means provided at least partly within the extension member for retracting the extension member rapidly within the inner member, the improvement comprising spring means for biasing the parts of the clamping ring towards a closed position, and hydraulic piston-and-cylinder means for opening the parts of the clamping ring against the force of the spring means.
Dependencies are inferred from the claim text.