Automatic regulating devices for hydraulic barrel-type pumps or motors

Claim 1

AUTOMATIC ADJUSTMENT DEVICE FOR HYDRAULIC PUMPS AND MOTORS COMPRISING A ROTARY BARREL HAVING MULTIPLE PARALLEL PISTON-AND-CYLINDER ASSEMBLIES, SAID BARREL HAVING A FACE WITH APERTURES EACH COMMUNICATING WITH A SPECIFIC CYLINDER, A DISTRIBUTOR PLATE HAVING A FACE BEARING AGAINST SAID BARREL FACE HAVING IN FRONT OF SAID BARREL FACE AN INLET PORT AND AN EXHAUST PORT, SAID PORTS BEING SO DISPOSED THAT DURING THE BARREL ROTATION SAID APERTURES REGISTER SUCCESSIVELY WITH SAID PORTS, A SWASH PLATE FOR RECIPROCATING SAID PISTONS IN SAID CYLINDERS, SAID DISTRIBUTOR PLATE HAVING IN THE FACE THEREOF AN ORIFICE SPACED INTERMEDIATE SAID PORTS, A PASSAGE INTERCONNECTING SAID TWO ORIFICES, A SLIDE-VALVE CONTROLLING SAID PASSAGE COMPRISING A CONTROL CYLINDER COMMUNICATING WITH SAID EXHAUST PORT, A CONTROL PISTON IN SAID CONTROL CYLINDER CONTROLLING SAID SLIDE-VALVE A CALIBRATED COIL COMPRESSION SPRING URGING SAID SLIDE-VALVE CONSTANTLY IN THE OPENING DIRECTION AND IN THE CLOSING DIRECTION BY THE PRESSURE PREVAILING IN SAID EXHAUST PORT, THE FORCE OF SAID SPRING AND THE CROSS-SECTIONAL AREA OF SAID CONTROL CYLINDER BEING SUCH THAT THE DISPLACEMENT OF SAID SLIDE-VALVE IN THE CLOSING DIRECTION TAKES PLACE ONLY WHEN THE DELIVERY PRESSURE EXCEEDS A PREDETERMINED VALUE.