Abstract: A hydraulic valve includes a valve body having first and second ends, a bore extending therebetween, and first and second drain passages opening to the bore; a spool disposed in the bore and biased in a neutral position, the spool having first and second ends and first and second annuli axially spaced from the first and second ends respectively, whereby when the spool is in the neutral position, the first and second drain passages are connected to first and second bores respectively via the respective annulus, and wherein the spool is axially movable relative to the body by fluid acting on one of the ends to block fluid flow from the first and second bores to the first and second drain passages.

Abstract: A rotary valve capable of high flow rates, minimal pressure drop, and rapid actuation is presented. According to one aspect, the rotary valve is characterized by a unique pressure balancing system operating on the rotary spool of the valve to reduce side force caused by pressure at the flow ports. According to another aspect, the rotary valve is characterized by a unique internal shiftable blocking spool in response to a failure condition or a modulating signal. According to another aspect, a unique interface is provided for sealing a port of a rotary valve to an outer surface of a rotary spool. According to another aspect, the rotary valve is characterized by a unique interface provided for sealing a port to an outer surface of the rotary spool. According to another aspect, a rotary valve is characterized by a unique three-way three-or-more-position configuration. According to another aspect, a rotary valve is characterized by a unique four-port three-position configuration.

Abstract: A hydraulic valve assembly includes a valve body having a spool bore, a valve inlet, and a plurality of cavities opening into the spool bore; and a spool disposed in the spool bore. A first cavity fluidly connected to a tank passage; a second cavity adjacent the first cavity and fluidly connected to a first work port; a third cavity adjacent the second cavity and fluidly connected to an inlet of a another valve; a fourth cavity adjacent the third cavity and fluidly connected to a second work port; a fifth cavity adjacent the fourth cavity and fluidly connected to the valve inlet; a sixth cavity adjacent the fifth cavity and fluidly connected to the first work port; a seventh cavity adjacent the sixth cavity; an eighth cavity adjacent the seventh cavity and fluidly connected to the valve inlet; a ninth cavity adjacent the eighth cavity and fluidly connected to the inlet of the other valve; and a tenth cavity adjacent the ninth cavity and fluidly connected to the valve inlet.

Abstract: A rotary valve capable of high flow rates, minimal pressure drop, and rapid actuation is presented. According to one aspect, the rotary valve is characterized by a unique pressure balancing system operating on the rotary spool of the valve to reduce side force caused by pressure at the flow ports. According to another aspect, the rotary valve (700) is characterized by a internal shiftable blocking spool (790) in response to a failure condition or a modulating signal. According to another aspect, an interface is provided for sealing a port of a rotary valve to an outer surface of a rotary spool. According to another aspect, the rotary valve is characterized by an interface provided for sealing a port to an outer surface of the rotary spool. According to another aspect, a rotary valve is characterized by a three-way three-or-more-position configuration. According to another aspect, a rotary valve is characterized by a four-port three-position configuration.

Abstract: A load sense passage in a load sense hydraulic system may be vented by allowing flow from the load sense passage to a reservoir via a drain passage when a first flow control valve is in a neutral position. This venting may be prevented by preventing flow from the load sense passage to a reservoir via the drain passage when the first flow control valve is in a flow-allowing position.

Abstract: A valve assembly includes a valve body having at least a first bore and a second bore, a flow passage connecting the first bore to the second bore, a plurality of ports opening to each bore respectively, the first bore being upstream of the second bore. First and second spools are disposed in the first and second bores, respectively, for controlling the flow of fluid to and from the respective ports. A check valve is disposed in the flow passage and configured to prevent fluid flow from the second spool towards the first spool through the flow passage while allowing fluid flow from one of the ports in the first bore towards the second spool through the flow passage.

Abstract: A rotary valve capable of high flow rates, minimal pressure drop, and rapid actuation is presented. According to one aspect, the rotary valve is characterized by a unique pressure balancing system operating on the rotary spool of the valve to reduce side force caused by pressure at the flow ports. According to another aspect, the rotary valve (700) is characterized by a internal shiftable blocking spool (790) in response to a failure condition or a modulating signal. According to another aspect, an interface is provided for sealing a port of a rotary valve to an outer surface of a rotary spool. According to another aspect, the rotary valve is characterized by an interface provided for sealing a port to an outer surface of the rotary spool. According to another aspect, a rotary valve is characterized by a three-way three-or-more-position configuration. According to another aspect, a rotary valve is characterized by a four-port three-position configuration.