Automatic control system for use with a hydraulic drive system

Claim 2

An automatic control system for use with a hydraulic drive system of the type which includes a source of pressurized hydraulic fluid and first and second hydraulic drive means deriving their power from said source of pressurized hydraulic fluid, comprising: differential valve means, having an inlet in fluid communication with said source of pressurized hydraulic fluid and having an outlet, for providing a hydraulic pressure differential between the inlet and outlet thereof; a flow divider having first and second signal inlets, a power inlet, and first and second power outlets, the power inlet thereof being in fluid communication with the outlet of said differential valve means and the first and second power outlets thereof being in fluid communication with said first and second hydraulic drive means, respectively; a first control unit having an inlet in fluid communication with said source of pressurized hydraulic fluid and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; first control valve means carried by said first control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said first control unit to the first and second signal inlets of said flow divider, respectively; first actuation means operatively connected to said first control valve means for actuating said first control valve means in response to stimulus from a source external to said automatic control system; flow divider valve means carried by said flow divider between the power inlet thereof and the first and second power outlets thereof, and in fluid communication with the first and second signal inlets thereof for controlling the relative rates of flow of hydraulic fluid from the power inlet to the first power outlet and from the power inlet to the second power outlet in response to the relative flow rates of hydraulic fluid from said first control unit.

Claim 3

An automatic control system as defined in claim 1 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 4

An automatic control system as defined in claim 1 wherein said first actuation means is characterized further to include: lever means operatively connected to said first control valve means for actuating said first control valve means in response to the application of manual force to said lever means.

Claim 5

An automatic control system as defined in claim 1 characterized further to include: a second control unit having an inlet in fluid communication with said source of pressurized hydraulic fluid and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; second control valve means carried by said second control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said control unit to the first and second signal inlets of said flow divider, respectively; and lever means operatively connected to said second control valve means for actuating said second control valve means in response to the application of manual force to said lever means.

Claim 6

An automatic control system as defined in claim 4 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; and tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 7

An automatic control system as defined in claim 1 characterized further to include: valve means interposed between the first and second power outlets of said flow divider and said first and second hydraulic drive means for reversing the direction of operation of said first and second hydraulic drive means.

Claim 8

An automatic control system for use with a reversible hydraulic drive system of the type which includes a reversible pump having a first port and a second port for providing a source of pressurized hydraulic fluid, and first and second reversible hydraulic drive motors deriving their power from said pressurized hydraulic fluid, each of said reversible hydraulic drive motors having a first port and a second port with the second ports thereof in fluid communication with the second port of said reversible pump, comprising: differential valve means, having a first port in fluid communication with the first port of said reversible pump, a second port, a high-pressure outlet port, and a low-pressure return port, for providing a hydraulic pressure differential between the high-pressure outlet and the low-pressure return thereof regardless of the direction in which said reversible pump is pumping hydraulic fluid; a flow divider having first and second signal inlets, and first, second and third power ports formed therein, the first power port thereof being in fluid communication with the second port of said differential valve means; a flow compensator having first, second, third and fourth power ports formed therein, the first and second power ports thereof being in fluid communication with the second and third power ports of said flow divider, respectively, the third power port thereof being in fluid communication with the first port of said first reversible hydraulic drive motor, and the fourth power port thereof being in fluid communication with the first port of said second reversible hydraulic drive motor, and having first and second selector ports formed therein; selector valve means having first and second inlet ports formed therein in fluid communication with the first and second power ports of said flow compensator, respectively, having first and second outlet ports formed therein in fluid communication with the first and second selector ports to said flow compensator, respectively, and having first and second actuation ports formed therein in fluid communication with the first and second ports of said reversible pump, respectively, for placing the first power port and the first selector port of said flow compensator in fluid communication and placing the second power port and the second selector port of said flow compensator in fluid communication when said reversible pump is pumping hydraulic fluid out through the first port thereof and, alternately, for placing the first power port and the second selector port of said flow compensator in fluid communication and placing the second power port and the first selector port of said flow compensator in fluid communication when said reversible pump is pumping hydraulic fluid out through the second port thereof; compensator valve means carried by said flow compensator between the first and third power ports thereof, and between the second and fourth power ports thereof for controlling the relative rates of flow of hydraulic fluid through said first and second reversible hydraulic drive motors from said flow compensator in response to load variations encountered by said first and second reversible hydraulic drive motors when said reversible pump is pumping hydraulic fluid out through the first port thereof; a first control unit having an inlet in fluid communication with the high-pressure outlet of said differential valve means and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; first control valve means carried by said first control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said first control unit to the first and second signal inlets of said flow divider, respectively; first actuation means operatively connected to said first control valve means for actuating said first control valve means in response to stimulus from a source external to said automatic control system; and flow divider valve means carried by said flow divider between the first power port and the second and third power ports thereof, and in fluid communication with the first and second signal inlets thereof for controlling the relative rates of flow of hydraulic fluid between the first power port and the second power port and between the first power port and the third power port in response to the relative pressure of hydraulic fluid acting on said flow divider valve means through the first and second signal inlets of said flow divider.

Claim 9

An automatic control system for use with a reversible hydraulic drive system of the type which includes a reversible pump having a first port and a second port for providing a source of pressurized hydraulic fluid, and first and second reversible hydraulic drive motors deriving their power from said pressurized hydraulic fluid, each of said reversible hydraulic drive motors having a first port and a second port with the second ports thereof in fluid communication with the second port of said reversible pump, comprising: differential valve means, having a first port in fluid communication with the first port of said reversible pump, a second port, a high-pressure outlet port, and a low-pressure return port, for providing a hydraulic pressure differential between the high-pressure outlet and the low-pressure return thereof regardless of the direction in which said reversible pump is pumping hydraulic fluid; a flow divider having first and second signal inlets, and first, second and third power ports formed therein, the first power port thereof being in fluid communication with the second port of said differential valve means; a flow compensator having first, second, third and fourth power ports formed therein, the first and second power ports thereof being in fluid communication with the second and third power ports of said flow divider, respectively, the third power port thereof being in fluid communication with the first port of said first reversible hydraulic drive motor, and the fourth power port thereof being in fluid communication with the first port of said second reversible hydraulic drive motor, and having first and second selector ports formed therein; selector valve means having first and second inlet ports formed therein in fluid communication with the first and second power ports of said flow compensator, respectively, having first and second outlet ports formed therein in fluid communication with the first and second selector ports to said flow compensator, respectively, and having first and second actuation ports formed therein in fluid communication with the first and second ports of said reversible pump, respectively, for placing the first power port and the first selector port of said flow compensator in fluid communication and placing the second power port and the second selector port of said flow compensator in fluid communication when said reversible pump is pumping hydraulic fluid out through the first port thereof and, alternately, for placing the first power port and the second selector port of said flow compensator in fluid communication and placing the second power port and the first selector port of said flow compensator in fluid communication when said reversible pump is pumping hydraulic fluid out through the second port thereof; compensator valve means carried by said flow compensator between the first and third power ports thereof, and between the second and fourth power ports thereof for controlling the relative rates of flow of hydraulic fluid through said first and second reversible hydraulic drive motors from said flow compensator in response to load variations encountered by said first and second reversible hydraulic drive motors when said reversible pump is pumping hydraulic fluid out through the first port thereof; a first control unit having an inlet in fluid communication with the high-pressure outlet of said differential valve means and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; first control valve means carried by said first control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said first control unit to the first and second signal inlets of said flow divider, respectively; first actuation means operatively connected to said first control valve means for actuating said first control valve means in response to stimulus from a source external to said automatic control system; and flow divider valve means carried by said flow divider between the first power port and the second and third power ports thereof, and in fluid communication with the first and second signal inlets thereof for controlling the relative rates of flow of hydraulic fluid between the first power port and the second power port and between the first power port and the third power port in response to the relative pressure of hydraulic fluid acting on said flow divider valve means through the first and second signal inlets of said flow divider.

Claim 10

An automatic control system as defined in claim 7 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; and tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 11

An automatic control system as defined in claim 7 wherein said first actuation means is characterized further to include: lever means operatively connected to said first control valve means for actuating said first control valve means in response to the application of manual force to said lever means.

Claim 12

An automatic control system as defined in claim 7 characterized further to include: a second control unit having an inlet in fluid communication with the high-pressure outlet of said differential valve means and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; second control valve means carried by said second control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said control unit to the first and second signal inlets of said flow divider, respectively; and lever means operatively connected to said second control valve means for actuating said second control valve means in response to the application of manual force to said lever means.

Claim 13

An automatic control system as defined in claim 10 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; and tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 14

An automatic control system for use with a hydraulic drive system of the type which includes a source of pressurized hydraulic fluid and first and second hydraulic drive means deriving their power from said source of pressurized hydraulic fluid, comprising: differential valve means, having an inlet in fluid communication with said source of pressurized hydraulic fluid and having an outlet, for providing a hydraulic pressure differential between the inlet and outlet thereof; a flow divider having first and second signal inlets, a power inlet, and first and second power outlets, the power inlet thereof being in fluid communication with the outlet of said differential valve means; a flow compensator, having first and second power inlets and first and second power outlets, the first and second power inlets thereof being in fluid communication with the first and second power outlets of said flow divider, respectively, and the first and second power outlets thereof being in fluid communication with said first and second hydraulic drive means, respectively; compensator valve means carried by said flow compensator between the first power inlet and the first power outlet, and between the second power inlet and the second power outlet thereof for controlling the relative rates of flow of hydraulic fluid to said first and second hydraulic drive means from said flow compensator in response to load variations encountered by said first and second hydraulic drive means; a first control unit having an inlet in fluid communication with said source of pressurized hydraulic fluid and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; first control valve means carried by said first control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said first control unit to the first and second signal inlets of said flow divider, respectively; first actuation means operatively connected to said firsT control valve means for actuating said first control valve means in response to stimulus from a source external to said automatic control system; flow divider valve means carried by said flow divider between the power inlet thereof and the first and second power outlets thereof, and in fluid communication with the first and second signal inlets thereof for controlling the relative rates of flow of hydraulic fluid from the power inlet to the first power outlet and from the power inlet to the second power outlet in response to the relative flow rates of hydraulic fluid from said first control unit communicated to the first and second signal inlets of said flow divider.

Claim 15

An automatic control system for use with a hydraulic drive system of the type which includes a source of pressurized hydraulic fluid and first and second hydraulic drive means deriving their power from said source of pressurized hydraulic fluid, comprising: differential valve means, having an inlet in fluid communication with said source of pressurized hydraulic fluid and having an outlet, for providing a hydraulic pressure differential between the inlet and outlet thereof; a flow divider having first and second signal inlets, a power inlet, and first and second power outlets, the power inlet thereof being in fluid communication with the outlet of said differential valve means; a flow compensator, having first and second power inlets and first and second power outlets, the first and second power inlets thereof being in fluid communication with the first and second power outlets of said flow divider, respectively, and the first and second power outlets thereof being in fluid communication with said first and second hydraulic drive means, respectively; compensator valve means carried by said flow compensator between the first power inlet and the first power outlet, and between the second power inlet and the second power outlet thereof for controlling the relative rates of flow of hydraulic fluid to said first and second hydraulic drive means from said flow compensator in response to load variations encountered by said first and second hydraulic drive means; a first control unit having an inlet in fluid communication with said source of pressurized hydraulic fluid and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; first control valve means carried by said first control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said first control unit to the first and second signal inlets of said flow divider, respectively; first actuation means operatively connected to said firsT control valve means for actuating said first control valve means in response to stimulus from a source external to said automatic control system; flow divider valve means carried by said flow divider between the power inlet thereof and the first and second power outlets thereof, and in fluid communication with the first and second signal inlets thereof for controlling the relative rates of flow of hydraulic fluid from the power inlet to the first power outlet and from the power inlet to the second power outlet in response to the relative flow rates of hydraulic fluid from said first control unit communicated to the first and second signal inlets of said flow divider.

Claim 16

An automatic control system as defined in claim 12 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; and tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 17

An automatic control system as defined in claim 12 wherein said first actuation means is characterized further to include: lever means operatively connected to said first control valve means for actuating said first control valve means in response to the application of manual force to said lever means.

Claim 18

An automatic control system as defined in claim 12 characterized further to include: a second control unit having an inlet in fluid communication with said source of pressurized hydraulic fluid and having first and second signal outlets in fluid communication with the first and second signal inlets of said flow divider, respectively; second control valve means carried by said second control unit between the inlet thereof and the first and second signal outlets thereof for controlling the relative rates of flow of hydraulic fluid through the first and second signal outlets of said control unit to the first and second signal inlets of said flow divider, respectively; and lever means operatively connected to said second control valve means for actuating said second control valve means in response to the application of manual force to said lever means.

Claim 19

An automatic control system as defined in claim 15 wherein said first actuation means is characterized further to include: sensor means operatively connected to said first control valve means for actuating said first control valve means; and tracer means operatively connected to said sensor means and engageable with a suitable reference datum for actuating said sensor means in response to stimulus imparted thereto by said reference datum; and wherein said sensor means actuates said first control valve means in response to the actuation of said sensor means by said tracer means.

Claim 20

An automatic control system as defined in claim 12 characterized further to include: valve means interposed between the first and second power outlets of said flow compensator and said first and second hydraulic drive means for reversing the direction of operation of said first and second hydraulic drive means.