Hydraulic control system for operating multiple remote devices with a minimum number of connecting conduits

In a hydraulic system, first and second hydraulic motor means, selector valve means movable to first and second positions in response to first and second respective control pressures present in the low pressure side of the system for operatively connecting said valve means in said first position to said first hydraulic motor means and in said second position to said second hydraulic motor means, operator valve means including a direction selector valve for reversing the first and second motor means and a pressure control valve for selecting the pressure level operative in the low pressure side of the system to actuate said selector valve means to said first or second position, a shuttle valve responsive to the high pressure side of the system in any operative position of said direction selector and pressure control valves, and a pilot pressure conduit connecting the low pressure side of the system to said selector valve means through said shuttle valve.

In a hydraulic system, first and second hydraulic motor means, selector valve means movable to first and second positions in response to first and second respective control pressures present in the low pressure side of the system for operatively connecting said valve means in said first position to said first hydraulic motor means and in said second position to said second hydraulic motor means, a directional control valve controlling the direction of operation of the first and second motor means and a control pressure selector valve for selection by the operator of the first and second control pressures, said selector valve means and first and second motor being supported from a carriage movable vertically on an upright of a lift truck, or the like, and two hydraulic conduits reeved on the upright connecting the directional control valve to the selector valve means, a shuttle valve connected between said hydraulic conduits and responsive to the pressure in the conduit carrying the highest pressure fluid for communicating to said selector valve means the lower pressure fluid in the other conduit in which is established said first or second control pressure by said control pressure selector valve.

In a hydraulic system, first and second hydraulic motor means, selector valve means movable to first and second positions in response to first and second respective control pressures present in the low pressure side of the system for operatively connecting said valve means in said first position to said first hydraulic motor means and in said second position to said second hydraulic motor means, a directional control valve controlling the direction of operation of the first and second motor means and a control pressure selector valve for selection by the operator of the first and second control pressures, said control pressure selector valve being located downstream of said directional control valve.

In a hydraulic system, first, second and third hydraulic motor means, selector valve means movable to first, second and third positions in response to first, second and third respective control pressures present in the low pressure side of the system for operatively connecting said valve means in said first position to said first motor means, in said second position to said second motor means, and in said third position to said third motor means, operator valve means adapted to select the operation of said first, second or third motor means and to establish said first, second or third control pressures, two conduits connected from said operator valve means to said selector valve means, and shuttle valve means operatively connected between said conduits responsive to the high pressure fluid conduit for conducting control pressure from the low pressure fluid conduit to said selector valve means.