Hydraulic summating system

Claim 2

A summating system for providing the requisite pressurized fluid for one or more hydraulically operated functions including a prime mover, a plurality of fixed displacement pumps, each of which provides fluid under pressure in a system to operate a plurality of functions, at least one of which pumps is capable of utilizing the total output of said prime mover, relief valve means responsive to the sum of the pressures in the systems supplied by each of said pumps, whereby at least one of said pumps can utilize the total output of said prime mover or any portion thereof as determined by the demands of the hydraulically operated functions supplied thereby, said relief valve means functioning to relieve the pressure in one or more of said systems when the sum of the presures in the system exceeds the maximum allowable pressure.

Claim 3

A summating system for insuring that the various demands of hydraulically operated functions receive the required pressurized fluid to accomplish their intended functions on demand, including a prime mover, first and second constant displacement pumps having fluid inlets for receiving low pressure fluid and outlets containing pressurized fluid, each of said first and second pumps being part of a separate system to provide fluid under pressure to a plurality of hydraulically operated functions, pressure relief valve means responsive to the fluid under pressure in the outlet conduits of each of said pumps, each of said relief valve means including spring-biased valves controlling the flow of fluid under pressure between the outlet and inlet conduits of each of said pumps, each of said valves having a valve head exposed to the pressure in the outlet conduit of one of said pumps and an additional area exposed to the pressure in the outlet conduit of the other of said pumps whereby when total force exerted of each of said valves exceeds the presetting thereof at least one of the valves will open to return the sum of the pressures in said outlet conduits to the total maximum allowable pressure as predetermined by said prime mover.

Claim 4

A summating system for insuring that the various demands of hydraulically operated functions receive the required pressurized fluid to accomplish their intended functions on demand, including a prime mover, first and second constant displacement pumps having fluid inlets for receiving low pressure fluid and outlets containing pressurized fluid, each of said first and second pumps being part of a separate system to provide fluid under pressure to a plurality of hydraulically operated functions, pressure relief valve means responsive to the fluid under pressure in the outlet conduits of each of said pumps, each of said relief valve means including spring-biased valves controlling the flow of fluid under pressure between the outlet and inlet conduits of each of said pumps, each of said valves having a valve head exposed to the pressure in the outlet conduit of one of said pumps and an additional area exposed to the pressure in the outlet conduit of the other of said pumps whereby when total force exerted of each of said valves exceeds the presetting thereof at least one of the valves will open to return the sum of the pressures in said outlet conduits to the total maximum allowable pressure as predetermined by said prime mover.

Claim 5

A system as set forth in claim 2, wherein the relief valves set forth each has a valve head portion closing off the flow to the inlet of said pumps, which head portion is exposed to and controls the flow from the high-pressure conduit of one of said pumps, And a piston area exposed to the fluid under pressure in the outlet conduit of the other of said pumps.

Claim 6

A system as set forth in claim 2 in which one of said pumps is positioned to regulate the flow of hydraulic fluid under pressure in a system controlling a first track motor, swing motor, and crowd cylinder of a hydraulically operated excavator and the other of said pump controls the fluid under pressure in a system which controls a second track motor, hoist cylinder, and tool cylinder.

Claim 7

A system as set forth in claim 4 in which the first track motor, swing motor, and crowd cylinder functions are serially disposed and the second track motor, hoist, and tool cylinders are also located in series.

Claim 8

A system as set forth in claim 2 including pilot means for controlling the flow between the high-pressure conduit of each of said pumps and one of said relief valves, whereby small relief valves can be utilized while insuring that there can be rapid by-pass of fluid under pressure from said high-pressure conduits in the event the maximum allowable pressure in the system exceeds that which has been determined by the setting of said relief valves.

Claim 9

A summating valve assembly for controlling the fluid under pressure in systems supplied by fixed displacement pumps including a relief valve for each of said pumps, which valves are responsive to the fluid under pressure emanating from all of said pumps, sid valves controlling the flow of fluid between the outlet and inlet of said pumps to relieve the pressure in the systems when the summated outlet pressures of said pumps exceed the maximum allowable pressure.

Claim 10

A summating valve assembly for controlling the fluid under pressure in systems supplied by fixed displacement pumps including a relief valve for each of said pumps, which valves are responsive to the fluid under pressure emanating from all of said pumps, sid valves controlling the flow of fluid between the outlet and inlet of said pumps to relieve the pressure in the systems when the summated outlet pressures of said pumps exceed the maximum allowable pressure.

Claim 11

A valve assembly as set forth in claim 7 in which each valve is a spring-biased relief valve in which the setting thereof equals the maximum allowable force permitted to act on the valve which is equal to the exposed valve area multiplied by the pressures existing in the systems supplied by said pumps.

Claim 12

A valve assembly as set forth in claim 8 in which the system consists of two fixed displcement pumps and thus there are provided two valaves, each of which has a valve head portion exposed to the output of one of the fixed displacement pumps and a piston portions exposed to the output pressure of the other of said fixed displacement pumps.

Claim 13

A summating system for providing the requisite pressurized fluid for one or more hydraulically operated functions including a prime mover, a pluraltiy of fixed displacement funtions each of which provides fluid under pressure in a system to operate a plurality of functions, but each being capable of utilizing a total output of said prime mover, relief valve means responsive to the sum of the pressures in the systems supplied by each of said pumps, whereby each of said pumps can utilize the total output of said prime mover or any portion thereof as determined by the demands of the hydraulically operated functions supplied thereby, said relief valve means functioning to relieve the pressure in said system when the sum of the pressures in the systems exceeds the maximum allowable pressure.

Claim 14

A summating system for providing the requisite pressurized fluid for one or more hydraulically operated functions including a prime mover, a pluraltiy of fixed displacement funtions each of which provides fluid under pressure in a system to operate a plurality of functions, but each being capable of utilizing a total output of said prime mover, relief valve means responsive to the sum of the pressures in the systems supplied by each of said pumps, whereby each of said pumps can utilize the total output of said prime mover or any portion thereof as determined by the demands of the hydraulically operated functions supplied thereby, said relief valve means functioning to relieve the pressure in said system when the sum of the pressures in the systems exceeds the maximum allowable pressure.

Claim 15

A summating system for providing the requisite pressurized fluid for one or more hydraulically operated functions including a prime mover, a plurality of fixed displacement pumps, each of which provides fluid under pressure in a system to operate a plurality of functions, but each being capable of utilizing a total output of said prime mover, relief valve means responsive to the sum of the pressures in the systems supplied by each of said pumps, whereby each of said pumps can utilize the total output of said prime mover or any portion thereof as determined by the demands of the hydraulically operated functions supplied thereby, said relief valve means including a relief valve for each of said pumps and defining areas reaponsive to the fluid under pressure emanating from each of said pumps and functioning to relieve the pressure in one or more of said systems when the sum of the pressures in the systems exceeds the maximum allowaBle pressure.

Claim 16

A summating system for providing the requisite pressurized fluid for one or more hydraulically operated functions including a prime mover, a plurality of fixed displacement pumps, each of which provides fluid under pressure in a system to operate a plurality of functions, but each being capable of utilizing a total output of said prime mover, relief valve means responsive to the sum of the pressures in the systems supplied by each of said pumps, whereby each of said pumps can utilize the total output of said prime mover or any portion thereof as determined by the demands of the hydraulically operated functions supplied thereby, said relief valve means including a relief valve for each of said pumps and defining areas reaponsive to the fluid under pressure emanating from each of said pumps and functioning to relieve the pressure in one or more of said systems when the sum of the pressures in the systems exceeds the maximum allowaBle pressure.