| 摘要 |
The invention relates to a hydraulic actuator (3) with a casing (10), a piston (12) which is movable in the casing and divides it into a first chamber (18) and a second chamber (16), and a piston rod (14) fixedly connected with the piston (12). Moreover the piston is movable towards an abutment surface (30) which is adapted to take up, against spring action, part of the weight of the appliance when the appliance (2) is in the second lowered position. Preferably the actuator has a second piston (22) which runs along the piston rod (14) and which is adapted to divide the first chamber into a third chamber (18a) and a fourth chamber (18b), a surface of said second piston facing the first piston constituting said abutment surface (30). The actuator is intended to be used to operate a vertically adjustable appliance which is mounted on a vehicle.
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