Abstract: A switching device for alternately connecting a hydraulic drive of a lubricating pump to a pressure line and to a return line of a hydraulic circuit. The switching device includes first and second drive lines connected to the hydraulic drive, and pressure and return drive lines connected to the pressure and return lines. A switching valve is in fluid communication with the drive lines and is switchable between first and second switching states to connect the pressure drive line to the first drive line or to the second drive line. A plurality of hydraulic control lines control the position of the switching valve. The drive lines are configured to conduct a first volumetric flow of hydraulic fluid and the hydraulic control lines are configured to conduct a second volumetric flow of the hydraulic fluid different than the first volumetric flow.

Abstract: A fluid supply system includes a pump body having a main bore connectible through inlet check valves to draw secondary fluid from a first fluid reservoir and through outlet check valves to supply it to a secondary fluid function upon reciprocation of a free piston in the main bore. The free piston includes a pair of coaxial driving pistons on either side which extend into main passages which are alternately connected to a pressurized primary fluid source to cause reciprocation of the free piston. A first spool valve which responds to the completion of a free piston stroke activates a second spool valve which changes the primary fluid source connections to the driving pistons.