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US 5,699,665 AGranted
Control system with induced load isolation and relief
AssigneeCommercial Intertech Corp.
InventorGregory T. Coolidge
Life of this patent
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AssigneeCommercial Intertech Corp.
InventorGregory T. Coolidge
Estimating the term…
A pressure-responsive hydraulic control system (10) has a load-sensing flow-compensated pump (S) connected to a plurality of work sections; with a direction control valve (26, 26') and a pressure compensator valve in each work section; and with a flow-regulated logic check system (45); a flow-metered logic check system (40); an isolation circuit (60, 160, 260); and an induced load check system (70). Each pressure compensator valve is supplied flow-metered fluid from the respective direction control valve and supplies flow-regulated fluid to a hydraulic motor. The flow-regulated logic check system (45) provides a flow-regulated maximum output signal, and the flow-metered logic check system (40) provides a flow-metered maximum output signal. The isolation circuit (60, 160, 260) has an isolation valve (61, 161, 261) and a relief valve (67, 167, 267), receives the flow-regulated maximum output signal and flow-metered maximum output signal, supplies a load signal to the pump and supplies an isolation outlet signal to the induced load check system (70). The induced load check system compares the isolation outlet signal to the flow-regulated fluid signal for the respective work section and supplies the higher to the pressure compensator valve for that work section, whereby the pressure compensating valves and the relief valve are isolated from induced loads introduced in the flow-regulated maximum output signal by loads on the hydraulic motors. In lieu of an isolation circuit, a relief circuit (360) may be provided for certain applications.
A pressure-responsive hydraulic control system comprising, a plurality of work sections, a load-sensing flow-compensated source which creates a margin pressure connected by a parallel flow inlet conduit to said work sections and having a source return line, a hydraulic motor in each of said work sections operatively connected to a load, a direction control valve in each of said work sections connected to said inlet conduit and to said hydraulic motor, metering notches in said direction control valves controlling the flow of fluid from said source to said hydraulic motor, a pressure compensator valve in each of said work sections inputting flow-metered fluid from said metering notches and outputting flow-regulated fluid to said hydraulic motor, said pressure compensator valves having flow-metered pressure acting on one end thereof and a spring and a compensator control signal operating on the other end thereof, a flow-regulated logic check system interconnecting each of said work sections and providing a flow-regulated maximum output signal, a flow-metered logic check system interconnecting each of said work sections and providing a flow-metered maximum output signal, and an isolation circuit having an isolation valve and a relief valve and receiving said flow-regulated maximum output signal and said flow-metered maximum output signal and supplying a load signal to said source return line and supplying an isolation outlet signal to an induced load check system which also receives a flow-regulated fluid signal from each of said work sections and supplying as said compensator control signal to each of said work sections the highest pressure signal of said isolation outlet signal and the flow-regulated fluid signal for said work section, whereby said pressure compensating valves and said relief valve are isolated from induced loads introduced in said flow-regulated maximum output signal by said load on said hydraulic motor of at least one of said work sections.
A pressure-responsive hydraulic control system comprising, a plurality of work sections, a load-sensing flow-compensated source which creates a margin pressure connected by a parallel flow inlet conduit to said work sections and having a source return line, a hydraulic motor in each of said work sections operatively connected to a load, a direction control valve in each of said work sections connected to said inlet conduit and to said hydraulic motor, metering notches in said direction control valves controlling the flow of fluid from said source to said hydraulic motor, a pressure compensator valve in each of said work sections inputting flow-metered fluid from said metering notches and outputting flow-regulated fluid to said hydraulic motor, said pressure compensator valves having flow-metered pressure acting on one end thereof and a spring and a compensator control signal operating on the other end thereof, a flow-regulated logic check system interconnecting each of said work sections and providing a flow-regulated maximum output signal, a flow-metered logic check system interconnecting each of said work sections and providing a flow-metered maximum output signal, and a relief circuit having a relief valve and receiving said flow-regulated maximum output signal and said flow-metered maximum output signal and supplying a load signal to said source return line and supplying a relief outlet signal to an induced load check system which also receives a flow-regulated fluid signal from each of said work sections and supplying as said compensator control signal to each of said work sections the highest pressure signal of said relief outlet signal and the flow-regulated fluid signal for said work section, whereby flow output is maintained at all of said work stations when said relief valve is limiting pressure.
A pressure-responsive hydraulic control system comprising, a plurality of work sections, a load-sensing flow-compensated source which creates a margin pressure connected by a parallel flow inlet conduit to said work sections and having a source return line, a hydraulic motor in each of said work sections operatively connected to a load, a direction control valve in each of said work sections connected to said inlet conduit and to said hydraulic motor, metering notches in said direction control valves controlling the flow of fluid from said source to said hydraulic motor, a pressure compensator valve in each of said work sections inputting flow-metered fluid from said metering notches and outputting flow-regulated fluid to said hydraulic motor, said pressure compensator valves having flow-metered pressure acting on one end thereof and a spring and a compensator control signal operating on the other end thereof, a flow-regulated logic check system interconnecting each of said work sections and providing a flow-regulated maximum output signal, a flow-metered logic check system interconnecting each of said work sections and providing a flow-metered maximum output signal, a source return line receiving said flow-metered maximum output signal, and an induced load check system receiving said flow-regulated maximum output signal and a flow-regulated fluid signal from each of said work sections and supplying as said compensator control signal to each of said work sections the highest pressure signal of said flow-regulated maximum output signal and the flow-regulated fluid signal for said work section.
Dependencies are inferred from the claim text.