Abstract: A hydraulic system includes a charge pump which supplies fluid to variable displacement main pump, a fluid reservoir and valve unit. The valve unit includes a hollow housing having a first end communicated with the reservoir and a second end communicated with the charge pump and the main pump. A housing valve land member is located between the first and second ends. A valve member is movably mounted in the housing. The valve member has a valve disk attached to first and second valve stems which project from opposite sides of the valve disk. The valve disk has a central position wherein the valve disk is received by the ring. The valve stems are slidably supported by stem support members at opposite ends of the housing. A hollow sleeve projects from an end of the valve unit. A spring is mounted in the sleeve and is engagable with an end of one of the valve stems and is biased to urge the valve member away from the sleeve.

Abstract: A hydraulic system is provided for an engine driven vehicle. The hydraulic system includes a higher pressure engine driven pump for supplying pressurized fluid to a higher pressure circuit via a first supply line. The system also includes a lower pressure engine driven pump for supplying lower pressure fluid to a lower pressure circuit via a second supply line. The system also includes a pressure responsive relief valve. The relief valve has a sensing port connected to the first supply line, an inlet connected to the first supply line, and an outlet connected to the second circuit via the second supply line. The relief valve opens when a demand of the higher pressure circuit is satisfied. A cut-off valve controls communication between the high pressure circuit and a reservoir, and a control unit controls the cut-off valve as a function of operation of the high pressure circuit.

Abstract: An single event upset (SEU) tolerant system for detecting and correcting an SEU includes a decision element (200) for receiving a plurality of outputs (120) from a plurality of signal generators (105) and producing an output (130) therefrom. The decision element includes voters which provide two levels of voting for the plurality of redundant outputs (120). First-level voters (300) provide intermediate voted outputs (315) which are received by a second-level voter to determine an output (130). An output disabler (400) determines when an output is provided external to the decision element. A plurality of comparators (210) receive intermediate voted outputs (315) from first-level voters and compare with a plurality of outputs from a plurality of signal generators to determine upset detected signals (125). An upset detected signal controls the selection of feedback for an element having experienced an SEU.

Abstract: Router jig apparatus includes a base portion, a router positioning portion, a workpiece orbiting portion and a workpiece positioning portion. The base portion includes a quadrangular frame section disposed generally horizontally and a supporting stand extending downwardly from the frame section. The router positioning portion includes a plate section slidably engageable with the frame section, the plate section includes a central first opening of a shape to pass a motor of an inverted router and retain a work surface surrounding a bit thereof. The workpiece orbiting portion includes a guide section disposed above and closely adjacent to the frame section, the guide section including a large circular second opening therein. A disc member is rotatably positioned within the guide section opening, generally in a common plane therewith, the disc member including a central third opening.