| 摘要 |
A hydraulic actuator (1) with automatic wear take-up, is formed with a first piston (17) sliding in a blind bore (13), a second piston (33) in a bore made in the first piston, and an output rod (3) bearing on the second piston. A first chamber (27) is formed between the blind bore and the first piston and a second chamber (37) is formed between the bore and the second piston. A piece (19) having a shoulder (23) is fixed, on its side of smaller diameter, to an end (21) of the first piston confronting the first chamber, forming an annular space. The annular space contains an annular gasket (39) and stop (41), so as to divide the first chamber into two volumes (43, 45), one (45) connected to a pressure generator (7) and the other (43) communicating with the second chamber through a duct (47) made in the end of the first piston. The two volumes communicate with one another, at rest, via a passage provided between the gasket, the stop and the piece. When pressure in the first chamber exceeds a specific amount, communication between the two chambers is interrupted, by the shoulder coming to bear on the annular gasket.
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