Hydraulic power circuit with emergency lowering provisions

Abstract

Abstract HYDRAULIC POWER CIRCUIT INCLUDING A LIFT CYLINDER FOR RAISING A LOAD, AND A DIRECTIONAL CONTROL VALVE FOR THE CYLINDER WHICH IS ACTUATED BY A LOW PRESSURE REMOTE CONTROL SYSTEM. THE REMOTE CONTROL SYSTEM NORMALLY RECEIVES MOTIVE FLUID FROM A PUMP, BUT, WHEN THE PUMP IS DISABLED OR IDLE, THE CONTROLS MAY BE ADJUSTED TO EFFECT LOWERING OF AN ELEVATED LOAD UTILIZING THE FLUID UNDER LOAD PRESSURE IN THE CYLINDER. FOR THIS PURPOSE, THE CIRCUIT INCLUDES A SWITCH VALVE WHICH ALTERNATELY CONNECTS THE INLET CONDUIT OF THE REMOTE CONTROL SYSTEM WITH THE PUMP OR THE CYLINDER DEPENDING UPON WHETHER PUMP OUTPUT PRESSURE IS ABOVE OR BELOW A PREDETERMINED VALUE, AND A PRESSURE REGULATOR FOR REDUCING THE PRESSURE OF THE FLUID DELIVERED TO THE REMOTE CONTROL SYSTEM FROM THE CYLINDER. IN APPLICTIONS WHERE THE POWER PUMP FOR THE CYLINDER SERVES ALSO AS THE NORMAL SOURCE OF MOTIVE FLUID FOR THE REMOTE CONTROL SYSTEM, THE PRESSURE REGULATOR MAY BE ARRNAGED BETWEEN THE SWITCH VALVE AND THE REMOTE CONTROL SYSTEM SO THAT IT CAN SERVE TO REDUCE THE PRESSURE OF THE FLUID SUPPLIED TO THAT SYSTEM FROM EITHER THE POWER PUMP OR THE LIFT CYLINDER.

Inventors

• 👤 Waldo G Fruehauf

Bibliographic Details