Abstract: An automatic shutoff valve has a main inlet, a main outlet, and a main passage from the main inlet to the main outlet formed in a valve body. A piston chamber formed in the valve body has a valve seat in the main passage. A piston is movable back and forth through the piston chamber between a first position in engagement with the valve seat to close the main passage and a second position out of engagement with the valve seat to open the main passage. A first seal lies between the piston and the piston chamber to create on the piston a first area against which fluid pressure in the main passage acts to urge the piston toward its second position. An actuator is movable through a control chamber in fluid communication with one end of the piston chamber.

Abstract: A control system for a hydraulically powered self advancing mine roof support, which system ensures that a hydraulically extensible chock leg of the support is set to a predetermined pressure, irrespective of the length of time that a main inlet valve is held open comprises an auxiliary valve interposed between a main valve and a chock leg(s) in a fluid supply line extending from a high pressure line to the support, a bypass line connected to the high pressure line in advance of the main valve and extending to the auxiliary valve, the auxiliary valve being so constructed as to open upon sensing a predetermined pressure and to close upon sensing a higher predetermined pressure.

Abstract: Two hydraulic brakes or clutches being primary users, are alternately, delayedly, hydraulically energized from a constant volumetric flow rate pump feeding also a secondary user via a pressure controller with a differential piston operated by feedback ducts from the primary users via a throttle valve. The latter valve is bypassed through a check valve for undelayed de-energization. A selector valve is disposed between the branch point for the secondary user and upstream as to energizing fluid from the feedback connection to the primary user. The pressure controller is described further as to several structural details.

Abstract: The transition module is intended to be assembled with at least three action modules constituting a sequencer and comprises an elementary logical gate having two inputs and one output, two inputs for receiving the output signals of two predetermined action modules and directing the signals to the inputs of the logical gate, one output for directing the output of the logical gate towards a predetermined input of the third action module and a Y-duct for directly connecting the output of the third action module to a predetermined input of each of the first two action modules.

Abstract: An altitude compensated vacuum control system for regulating the vacuum servo mechanism of an internal combustion engine of the type having a distributor with a vacuum servo controlled advance mechanism incorporating a positive stop for maximum spark advance, a carburetor to provide a source of vacuum to operate said vacuum servo mechanism and a vacuum control valve assembly for regulating the vacuum servo mechanism of said distributor. The vacuum control valve assembly receives a spark port vacuum signal from the carburetor to maintain a predetermined vacuum spark advance as the engine begins to accelerate.