Load responsive system with synthetic signal
AssigneeThe Scott Fetzer Company
InventorWendell E. Miller
Life of this patent
Estimating the term…
Abstract
A load responsive hydraulic system uses a signal supply restrictor, a synthetic signal generator and a unique directional control valve to provide a signal fluid having a pressure magnitude which is at a predetermined value above the load actuating pressure of the system and which is called a synthetic signal pressure. The effective output of the system's pump is controlled by the difference between the pressure of the pump and the pressure magnitude of this synthetic signal pressure. During pressure operation of the system, the directional control valve applies the synthetic signal pressure to the pump control mechanism; and during standby operation, the control valve applies a signal fluid to the pump control mechanism whose pressure magnitude is not increased by the synthetic signal generator.
Claims78
A load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (12 of FIGS. 1 & 3, or 102 of FIG. 2) and a sump (14), a fluid actuated device (28), a directional control valve (26 of FIG. 1, 226 of FIG. 2, or 326 of FIG. 3) having a movable valving element (50, 250, or 350) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (16 of FIGS. 1 & 3, or 120 of FIG. 2) having a signal chamber (34 of FIGS. 1 & 3, or 116b of FIG. 2) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement of which comprises:
- a. signal control means (62 + 54a + 46 + 74 of FIG. 1, 262 + 254a + 246 + 274 of FIG. 2, or 184 + 186a + 190a of FIG. 3) including a signal control port (60, 260, or 360) in said control valve and including said valving element, for establishing a first fluid flow path (incl. 54a of FIG. 1, 254a of FIG. 2, or 184 + 186a + 190a of FIG. 3) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 46 + 74 of FIG. 1, 246 + 274 of FIG. 2, or 184 + 186a + 190a of FIG. 3) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. logic means (20b) having a first logic port (95b) connected to said signal chamber, having a second logic port (94b) connected to said signal control port, and having a third logic port (90b) adapted for connection to a fluid pressure, for establishing fluid communication from said first logic port to one of the other two of said logic ports having the higher fluid pressure therein, and for blocking fluid communication from said first logic port to the one of said other two logic ports having the lower fluid pressure therein;
- c. a signal supply restrictor (24 of FIGS. 1 & 2, or 198a of FIG. 3) being connected to said pump to receive fluid therefrom and being connected to said logic means to supply fluid to said signal chamber for use as said signal fluid;
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- d. a synthetic signal generator (52 of FIG. 1, 64 of FIG. 1A, 119 or 121 of FIG. 2, or 193a of FIGS. 3 & 3A) being interposed into one of said fluid paths and imposing a predetermined flow resistance to fluid flow through said one fluid flow path;
- e. whereby said first fluid flow path establishes fluid communication from said signal control port to said fluid actuated device to sense said load actuating pressure and thereby to apply said load actuating pressure to said second logic port when said directional control valve is in said operating position, said logic means establishes fluid communication from said signal chamber to said signal control port whenever the fluid pressure in said second logic port is greater then any fluid pressure applied to said third logic port, said signal supply restrictor is effective to supply fluid from said pump to said signal chamber and to supply fluid from said pump to said fluid actuated device through said first fluid flow path, and said synthetic signal generator is effective to increase the pressure magnitude of said signal fluid in said signal chamber to a predetermined value above the pressure magnitude of the load actuating pressure as sensed by said first fluid flow path.
In a load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (12 of FIG. 1 or 102 of FIG. 2) and a sump (14), a fluid actuated vehicle (28), a directional control valve (26 of FIG. 1 or 226 of FIG. 2) having a movable valving element (50 or 250) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (16 or FIG. 1 or 120 of FIG. 2) having a signal chamber (34 of FIG. 1 or 116b of FIG. 2) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement which comprises:
- a. signal control means (62 + 54a + 46 + 74 of FIG. 1, or 262 + 254a + 246 + 274 of FIG. 2) including a signal control port (60 or 260) in said control valve and including said valving element, for establishing a first fluid flow path (incl. 54a of FIG. 1, or 254a of FIG. 2) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 46 + 74 of FIG. 1, or 246 + 274 of FIG. 2) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- logic means (20b), having a first logic port (95b) connected to said signal chamber, having a second logic port (94b) connected to said control port, and having a third logic port (90b) adapted for connection to a fluid pressure, for establishing reversible fluid communication between said first logic port and the one of the other two of said logic ports having the higher fluid pressure therein, and for blocking fluid communication between said first logic port and the one of said other two logic ports having the lower fluid pressure therein;
- c. a signal supply restrictor (24) being connected to said pump to receive fluid therefrom and being connected to said signal chamber to supply fluid thereto for use as said signal fluid;
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- d. a synthetic signal generator (52 of FIG. 1, 64 of FIG. 1A, or 119 or 121 of FIG. 2) being interposed into one of said fluid flow paths and imposing a predetermined flow resistance to fluid flow through said one fluid flow path;
- e. whereby said first fluid flow path establishes fluid communication from said signal control port to said fluid actuated device to sense said load actuating pressure and thereby to apply said load actuating pressure to said second logic port when said directional control valve is in said operating position, said logic means establishes fluid communication from said signal chamber to said signal control port whenever the fluid pressure in said second logic port is greater than any fluid pressure applied to said third logic port, said signal supply restrictor is effective to supply fluid from said pump to said signal chamber and to supply fluid from said pump to said fluid actuated device through said first fluid flow path, and said synthetic signal generator is effective to increase the pressure magnitude of said signal fluid in said signal chamber to a predetermined value above the pressure magnitude of the load actuating pressure as sensed by said first fluid flow path.
A load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (12) and a sump (14), a fluid actuated device (28), a directional control valve (326) having a movable valving element (350) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (16) having a signal chamber (34) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement of which comprises:
- a. signal control means (184 + 186a + 190a) including a signal control port (360) in said control valve and including said valving element for establishing a first fluid flow path (incl. 184 + 186a + 190a) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 184 + 186a + 190a) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. logic means (20b), having a first logic port (95b) connected to said signal chamber, having a second logic port (94b) connected to said signal control port, and having a third logic port (90b) adapted for connection to a fluid pressure, for establishing fluid communication from said first logic port to the one of the other two of said logic ports having the higher fluid pressure therein, and for blocking fluid communication from said first logic port to the one of said other two logic ports having the lower fluid pressure therein;
- c. a valved signal supply restrictor (198a), including cooperating portions (194a and 196a) of said control valve and being connected to said pump (via inlet port 340a) and to said signal control port, for establishing a restricted flow path from said pump to said signal control port when said control valve is in said operating position, and for isolating said pump from said signal control port when said control valve is in said standby position;
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- d. a synthetic signal genertor (193a) being interposed in said first fluid flow path and imposing a predetermined flow resistance to fluid flow through said first fluid flow path;
- e. whereby fluid is supplied from said pump to said signal control port for use as said signal fluid, said first fluid flow path is established and said load actuating pressure is sensed by said first fluid flow path, said signal fluid is pressurized to a predetermined value above the pressure magnitude of said load actuating pressure to produce a synthetic signal by flowing through said synthetic signal generator and through said first fluid flow path to said fluid actuated device, and said synthetic signal is applied to said signal chamber to control said fluid responsive means and to control the pressure magnitude of said pump to a predetermined pressure magnitude above said synthetic signal, when said control valve is in said operating position and said load actuating pressure is greater than any fluid pressure applied to said third logic port.
A load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (12) and a sump (14), a fluid actuated device (28), a directional control valve (326) having a movable valving element (350) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (16) having a signal chamber (34) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement of which comprises:
- a. signal control means (184 + 186a + 190a) including a signal control port (360) in said control valve and including said valving element for establishing a first fluid flow path (incl. 184 + 186a + 190a) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 184 + 186a + 190a + 342a) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. logic means (20b), having a first logic port (95b) connected to said signal chamber, having a second logic port (94b) connected to said signal control port, and having a third logic port (90b) adapted for connection to a fluid pressure, for establishing fluid communication between said first logic port and the one of the other two of said logic ports having the higher fluid pressure therein, and for blocking fluid communication between said first logic port and the one of said other two logic ports having the lower fluid pressure therein;
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- c. means (valved signal supply restrictor 198a) for supplying pressurized fluid from said pump to said logic means through said second logic port (94b) of said logic means (20b) when said control valve is in said operating position;
- d. whereby said pump provides pressurized fluid to said second logic port for use as said higher fluid pressure when said control valve is in said operating position.
A directional control valve of the type which includes a body having an inlet port means (340a) and a work port (342a), return port means (344a) in said body, and a movable valving element selectively communicating said work port with said inlet port means and with said return port means, the improvement which comprises:
- a. a signal control port (360) in said body communicating with said valving element;
- b. means (186a + 190a) for establishing a first fluid flow path from said signal control port to said work port when said valving element communicates said inlet port means to said work port, and for selectively establishing a second fluid flow path from said signal control port to said return port means;
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- c. means (valved signal supply restrictor 198a) for establishing a restricted flow path from said inlet port means to said signal control port when said valving element communicates said inlet port means to said work port.
A directional control valve of the type which includes a body (336) having a spool bore (338) therein, having return port means (344a) intersecting said bore, having an inlet port (340a) intersecting said bore in spaced relationship to said return port means, and having a work port (342a) intercepting said bore intermediate of said inlet port and said return port means, and a valve spool being slidably fitted in said bore and being movable from a standby position wherein said work port is isolated from said inlet port and said return port to an operating position wherein said work port is communicated with said inlet port, the improvement which comprises:
- a. a signal control port (360) in said body intercepting said bore proximal to said inlet port and distal from said work port and said return port means;
- b. logic means (20b), having a first logic port (95b), having a second logic port (94b) connected to said signal control port, and having a third logic port (90b) for connection to a fluid pressure, for establishing fluid communication between said first logic port and the one of the two other of said logic ports having the highest fluid pressue therein;
- c. means, comprising a longitudinal passage (186a) and a radial passage (190a) in said valve spool, for communicating said signal control port with said return port means when said valve spool is in said standby position, and for communicating said signal control port with said work port when said valve spool is in said operating position;
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- d. means (groove 194a), in said valve spool, for establishing a restricted flow path from said inlet port to said signal control port when said valve spool is in said operating position, whereby said inlet port is communicated with said second logic port.
A directional control valve of the type which includes a body (36 or 236) having a spool bore (38 or 238) therein, having return port means (44a + 48, or 244b + 248) intersecting said bore, having an inlet port (40 or 240) intersecting said bore in spaced relationship to said return port means, and having a work port (42a or 242b) intercepting said bore intermediate of said inlet port and said return port means, and a valve spool (50 or 250) being slidably fitted into said bore and being movable from a standby position wherein said work port is isolated from said inlet port and said return port means to an operating position wherein said work port is communicated with said inlet port, the improvement which comprises:
- a. a signal control port (60 or 260) in said body;
- b. a load signal passage (54a or 254b) in said body communicating with said signal control port and intercepting said bore intermediate of said inlet port and work port;
- c. an attenuation signal passage (46 or 246) intercepting said bore proximal to said return port means and distal from both said work port and said inlet port;
- d. means, in said valve spool, for establishing a first fluid flow path from said signal control port to said work port through said load signal passage when said valve spool is in said operating position, and for establishing a second fluid flow path from said signal control port to said return port means through said attenuation signal passage when said valve spool is in said standby position;
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- e. a synthetic signal generator (52 of FIG. 1, 64 of FIG. 1A, 119 of FIG. 2, or 121 of FIG. 2) being interposed in one of said fluid flow paths.
In a load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (102) and a sump (14), a fluid actuated device (28), a directional control valve (226) having a movable valving element (250) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (120) having a signal chamber (116b) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement which comprises:
- a. signal control means (262 + 254a + 246 + 274) in said control valve including a signal control port (260) connected to said signal chamber and including said valving element, for establishing a first fluid flow path (incl. 260 + 254a) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 246 + 274) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. a signal supply restrictor (24) being connected to said pump to receive fluid therefrom and being connected to said signal control port (via logic valves 20a & 20b) to supply fluid thereto for use as said signal fluid;
- and
- c. a synthetic signal generator (121) being interposed in said second fluid flow path and imposing a predetermined flow resistance to fluid flow through said second fluid flow path whereby said synthetic signal generator is effective to increase the pressure magnitude of said signal fluid in said signal control port above that sensed by said second fluid flow path;
- d. whereby said fluid responsive means is controlled by said sump pressure and by said increase in pressure magnitude when said control valve is in said standby position, and said fluid responsive means is controlled by said load actuating pressure when said control valve is in the other of said positions.
In a load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (102) and a sump (14), a fluid actuated device (28), a directional control valve (226) having a movable valving element (250) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (120) having a signal chamber (116b) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement which comprises:
- a. signal control means (262 + 254a + 246 + 274) in said control valve including a signal control port (260) connected to said signal chamber and including said valving element, for establishing a first fluid flow path (260 + 254a) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 246 + 274) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. a signal supply restrictor (24) being connected to said pump to receive fluid therefrom and being connected to said signal control port (via logic valve 20a & 20b) to supply fluid thereto for use as said signal fluid;
- and
- c. a synthetic signal generator (121) being interposed in one of said fluid flow paths and imposing a predetermined flow resistance to fluid flow through said one fluid flow path whereby said synthetic signal generator is effective to increase the pressure magnitude of said signal fluid in said signal control port above that sensed by said one fluid flow path;
- d. whereby said fluid responsive means is controlled by said one sensed pressure and by said increase in pressure magnitude when said control valve is in said one position, and said fluid responsive means is controlled by said other sensed pressure when said control valve is in the other of said positions;
- said pump comprising a variable displacement pump (102) and said fluid responsive mechanism comprises a displacement control mechanism (120).
In a load responsive hydraulic system of the type which includes a source of pressurized fluid having a pump (12) and a sump (14), a fluid actuated device (28), a directional control valve (26) having a movable valving element (50) and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, a fluid responsive means (16 of FIG. 1, or 120 of FIG. 2) having a signal chamber (34 of FIG. 1, or 116b of FIG. 2) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, the improvement which comprises
- a. signal control means (62 + 54a + 46 + 74 of FIG. 1) in said control valve including a signal control port (60) connected to said signal chamber and including said valving element, for establishing a first fluid flow path (incl. 60 + 54a of FIG. 1) which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path (incl. 46 + 74 of FIG. 1) which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- b. a signal supply restrictor (24) being connected to said pump to receive fluid therefrom and being connected to said signal control port (via logic valves 20a & 20b) to supply fluid thereto for use as said signal fluid;
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- c. a synthetic signal generator in the form of a relief valve (52) being interposed in one of said fluid flow paths and imposing a predetermined flow resistance to fluid flow through said one fluid flow path, said synthetic signal generator being effective to increase the pressure magnitude of said signal fluid in said signal control port above that sensed by said one fluid flow path;
- d. whereby said fluid responsive means is controlled by said one sensed pressure and by said increase in pressure magnitude when said control valve is in said one position, and said fluid responsive means is controlled by said other sensed pressure when said control valve is in the other of said positions.
In a load responsive hydraulic system of the type which includes a pump (12 or 102), a sump (14), a fluid actuated device (28), a directional control valve (26 or 226) having a movable valving element and having both an operating position wherein fluid from said pump is supplied to said fluid actuated device at the load actuating pressure thereof and a standby position wherein said fluid actuated device is isolated from said pump, and a fluid responsive means (16 of FIG. 1, or 120 of FIG. 2) having a signal chamber (34 of FIG. 1, or 116b of FIG. 2) therein and being effective to control the pressure and the effective output of said pump in response to the pressure magnitude of a signal fluid supplied to said signal chamber, and which includes:
- a. a signal supply restrictor (24) connected to said pump to receive fluid from said pump;
- b. signal control means (60 + 62 + 46 + 54a, etc. of FIG. 1) including a signal control port in said control valve and including said valving element for establishing a first fluid flow path which communicates said signal control port with said fluid actuated device, for sensing said load actuating pressure when said control valve is in said operating position, for establishing a second fluid flow path which communicates said signal control port with said sump, and for sensing the fluid pressure in said sump when said control valve is in said standby position;
- c. signal conduit means (72 or 272) connecting said signal chamber to said signal supply restrictor and to said signal control port, whereby said signal supply restictor supplies fluid from said pump to said signal conduit for use as said signal fluid and the pressure magnitude of said signal fluid is controlled by said load actuating pressure when said control valve is in said operating position and by said sump pressure when said control valve is in said standby position;
- and
- d. a synthetic signal generator (52 and 64 of FIG. 1, or 119 or 121 of FIG. 2) having a predetermined flow resistance, being interposed in one of said fluid flow paths, and being effective to increase the pressure magnitude of said signal fluid by said flow resistance when said control valve is in the one of said positions wherein said one fluid flow path is established and said signal fluid flows through said synthetic signal generator and through said one fluid flow path;
- said control valve being of the type having a body with a spool bore therein, a work port intersecting said bore, a return port intersecting said bore, an inlet port intersecting said bore, and said valving element comprising a valve spool in said bore being movable from said standby position to said operating position, the improvement which comprises said signal control means comprising a load signal passage (54a of FIG. 1) which provides a portion of said first fluid flow path and which intercepts said bore intermediate of said inlet port (40 of FIG. 1) and said work port (42a of FIG. 1).
Dependencies are inferred from the claim text.