Abstract: A rotary air motor driven hydraulic pump has separate pressure and return actuators and first and second stage eccentric driven pistons 180 degrees out of phase and driven by the motor through a gear reduction unit. The pressure and return actuators are on/off/proportional valves and the pump has two pressure relief valves with one adjustable from outside of the pump for a user to set a pressure limit of the pump. Above a certain output pressure limit, a bypass valve shunts flow in excess of that needed to precharge the second stage compression chamber from the first stage piston to an elastic reservoir from which the hydraulic fluid pumped by the pump is drawn. To make the pump stall at a certain output pressure, a pressure limiting valve can be used that cuts off the air supply to the pump at the desired output pressure.

Abstract: A high pressure metering valve has a valve element with a closing portion, a metering portion and a rapid return portion. The closing portion seats against a corner seat at the end of a valve bore in which the metering portion has a close sliding fit. When the element is unseated, a flow rate can be metered depending on the overlapping length of the metering portion in the valve bore. At the opposite end of the metering portion, the rapid return portion is undercut to be of smaller area than the metering portion to provide a full open state for rapid fluid return.

Abstract: A rotary air motor driven hydraulic pump has separate pressure and return actuators and first and second stage eccentric driven pistons 180 degrees out of phase and driven by the motor through a gear reduction unit. The pressure and return actuators are on/off/proportional valves and the pump has two pressure relief valves with one adjustable from outside of the pump for a user to set a pressure limit of the pump. Above a certain output pressure limit, a bypass valve shunts flow in excess of that needed to precharge the second stage compression chamber from the first stage piston to an elastic reservoir from which the hydraulic fluid pumped by the pump is drawn. To make the pump stall at a certain output pressure, a pressure limiting valve can be used that cuts off the air supply to the pump at the desired output pressure.

Abstract: A high pressure metering valve has a valve element with a closing portion, a metering portion and a rapid return portion. The closing portion seats against a corner seat at the end of a valve bore in which the metering portion has a close sliding fit. When the element is unseated, a flow rate can be metered depending on the overlapping length of the metering portion in the valve bore. At the opposite end of the metering portion, the rapid return portion is undercut to be of smaller area than the metering portion to provide a full open state for rapid fluid return.

Abstract: A 4-way 3-position direct acting tandem center neutral valve has two 3-way, 2-position poppet valves configured so as to provide 4-way, 3-position tandem center neutral valve functions so that it is direct acting and essentially zero leak.

Abstract: A bi-directional metering valve assembly is provided to selectively direct hydraulic fluid under high pressure to a load. The assembly includes a valve block defining a first port that receives hydraulic fluid from a source, and a second port that directs hydraulic fluid toward a load. A rotatable valve member defines first and second apertures in an axial face that may be placed in selective communication with the first and second ports, respectively, to direct hydraulic fluid from the source to the load. At least one metering sealing assembly provides an interface between the valve block and the valve member. The metering sealing assembly includes a gasket that surrounds one of the first and second ports and defines a flange that is sized to completely overlap and seal the corresponding aperture. The valve member is operable to control the direction of fluid flow, and make fine adjustments to the hydraulic fluid flow rate.

Abstract: A concrete reinforcement cable tensioning system is variably adjustable to apply different crimping for different sized cables. The system includes a concrete reinforcement cable tensioner having a first actuator for tensioning a cable extending through a concrete structure and a second actuator for crimping a grommet onto the cable. A first hydraulic line is in fluid communication with the first actuator and selectively provides pressurized hydraulic fluid to the first actuator. A second hydraulic line is in fluid communication with the second actuator and selectively provides pressurized hydraulic fluid to the second actuator. A normally closed pilot operated sequencing valve is disposed in the first hydraulic line, and has a pilot line in fluid communication with the second hydraulic line for sensing a pressure in the second hydraulic line, wherein the sequencing valve opens to exhaust hydraulic fluid from the first actuator upon the pressure in the second hydraulic line reaching a predetermined pressure.

Abstract: A fluid flow control valve assembly that can be actuated using an electrically operated or pneumatically operated flow control valve includes a valve body having a fluid supply passageway, a fluid exhaust passageway, and a fluid bypass passageway. A pilot operated relief valve is disposed in the fluid bypass passageway, wherein the pilot operated relief valve blocks the fluid bypass passageway to create a pressure upstream of the pilot operated relief valve to actuate a different pilot operated device having a pilot line in fluid communication with the fluid bypass passageway upstream of the pilot operated relief valve. Fluid flowing through a venturi nozzle in the fluid bypass passageway that intersects the fluid exhaust passageway lowers the pressure in the fluid exhaust passageway.

Abstract: The invention provides a variable speed hydraulic pump designed to operate at a maximum horsepower throughout its pressure range by adjusting motor speed according to motor load parameters. In particular, the variable speed hydraulic pump includes a hydraulic pump unit coupled to a variable speed electric motor by a drive unit and to a hydraulic fluid tank for pressurizing and pumping hydraulic fluid when operated by the motor. A motor controller is electrically connected to the motor to supply drive signals to the motor based on electrical characteristics of the drive signals which are dependent on the load exerted on the motor. Suction from the load is provided by both the main pump and a bidirectional supercharging pump by reversing the direction of the motor and shifting a 4/3 valve to connect the main pump inlet to the load and its outlet to tank.

Abstract: A fluid flow control valve assembly that can be actuated using an electrically operated or pneumatically operated flow control valve includes a valve body having a fluid supply passageway, a fluid exhaust passageway, and a fluid bypass passageway. A pilot operated relief valve is disposed in the fluid bypass passageway, wherein the pilot operated relief valve blocks the fluid bypass passageway to create a pressure upstream of the pilot operated relief valve to actuate a different pilot operated device having a pilot line in fluid communication with the fluid bypass passageway upstream of the pilot operated relief valve. Fluid flowing through a venturi nozzle in the fluid bypass passageway that intersects the fluid exhaust passageway lowers the pressure in the fluid exhaust passageway.