Multi-stage hydraulic telescopic cylinder with positive control for the extension and retraction sequence of the telescopic members

摘要

In a double-acting, multi-stage, in particular two-stage, telescopic cylinder with extension and retraction sequence control, in order to improve the positional stability in the holding situation, the transfer of the pressure medium fed into the cylinder pressure space (112) during extension into the pressure space (122) of the first stage (12) is provided by a connecting line (123), mechanically opening when the first stage (12) passes into the extension end position, in the base (121) of the first stage (12), and during the retraction the transfer of the retraction pressure medium fed by a connecting line (124) in the intermediate piston base (121) continuing via a leadthrough (124') into the inner space (132) of the end stage (13) is provided via a connecting line (121) leading from the connecting line (124) in the intermediate piston base (121) to the annular cylinder space (112') and mechanically opening when the retracting end stage (13) runs against the intermediate piston base (121). In this way, the crossing of bores and by-passes which do not require leak-free seals sealing off the cylinder spaces from one another can be avoided. IMAGE