Multiple-stage hydraulic telescopic actuator with control of the extension or retraction of the telescopic parts in an imposed order

摘要

In order to improve the positional stability in the holding situation, in a multiple-stage, in particular two-stage, telescopic cylinder, which can be charged on both sides, having a control of the extension and retraction in an imposed order, the transfer of the pressure medium, fed into the cylinder pressure space (112) during extension, into the pressure space (122) of the first stage is provided by a connection line (123) in the bottom (121) of the first stage, which connection line unlocks mechanically when passing from the first stage into the final extension position, and, during retraction, the transfer of the retraction pressure medium fed in by a connection line (124), continuing via a passage (124') into the interior of the final stage, in the bottom (121) of the intermediate piston, is provided via a connection line (124") to the annular cylinder space (112'), which connection line leads from the connection line (124) in the bottom (121) of the intermediate piston to the annular cylinder space (112') and unlocks mechanically when the retracting final stage runs up against the bottom (121) of the intermediate piston. In this manner, moving over bore holes and deviations can be avoided, which require non-leak-proof seals sealing the cylinder spaces off against one another. IMAGE