| 摘要 |
A hydraulic operating device for controlling the active and stoppage phases of machines or machine tools is specified, with two main control valves which can each be guided into their on- and off-positions by means of a pilot-control valve and pass the pressure-medium flow from the supply-pressure source to the consumer when their valve pistons are simultaneously in the on-position and, when the valve pistons are simultaneously in the off-position or assume their alternative operating positions, produce a communicating connection between the consumer and the tank and thereby stop the machine. In order reliably to prevent the machine from being able to be switched on in the event of a malfunction of one of the components of the hydraulic operating circuit, the supply pressure is fed to the consumer via a flow route which comprises through-flow paths of the main control valves, which are connected in series only in their simultaneous on-position, and a hydraulic locking circuit is provided which, after a change-over of the main control valves into alternative operating positions, holds the control pistons of the main control valves in these alternative operating positions.
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