| 摘要 |
An actuator device for a gate or barrier which is adapted for use with a reservoir (26) of operating fluid. The reservoir is at a height relative to the device so as to form a pressure head. The actuating device comprises an hydraulic ram assembly (3, 31) which includes a cylinder (5) having a piston (4) therein, the piston (4) separating said cylinder into two chambers (13, 14). The ram assembly further includes a delivery and/or discharge port (6, 7, 6A, 7A) associated with each chamber (13, 14) through which the operating fluid can be delivered and/or discharged under pressure, an inlet line (18) through which the operating fluid is delivered to the hydraulic ram assembly (3, 31) the inlet line (18) being operatively connectible to the operating fluid reservoir, and outlet line (19) through which the operating fluid is discharged from the hydraulic ram assembly (3, 31); and control means (20) for causing selective delivery of the operating fluid to said chambers (13, 14). The arrangement is such that relative movement between said piston (4) and said cylinder (5) as a result of the selective delivery under the pressure of the pressure head of the operating fluid to said chambers (13, 14) causes movement of the gate or barrier (40). |
