A cam controlled hydraulic circuit for e.g. a copying machine tool may be used in the sequential control of a set of actuators. Two cam disc operated actuator pistons (2, 3) are connected by pressure conduits (8, 9) to a double acting working cylinder. The leakage losses occuring in the pressure transmitting system between the actuator piston (2, 3) and the working piston of the cylinder are compensated for by a pressure accumulator (19) supplied through two return valves (14, 15). The pressure in the accumulator is the same as, or greater than the pressure required for constant contact of the transmission elements between the pistons (2, 3) and the cam discs (5, 6). With a volume excess in the transmission system, the pressure fluid is returned to the storage tank. The associated valve lifts, when the working cylinder is blocked, and actuates the corresponding limit switch.
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