Supply apparatus for two receiving means having a pressure summation device

Abstract

The invention relates to a supply apparatus for two receiving means having a pressure summation device.A relief valve with a double control system is provided on a pipe shunted to the delivery pipe of the pump and has two control connections, a rod connecting the discharge member of the pressure summation device to the first of the said connections and a control pipe connecting that portion of the discharge pipe located between the connection of the latter to the delivery pipe and the relief valve to the second of the said connections.The invention is applicable to the realization of a supply apparatus with a pressure transfer system.BACKGROUND OF INVENTIONThe present invention relates to an apparatus for supplying pressurized fluid to two receiving means with pressure transfer by means of a double control valve.Apparatuses for supplying two receiving means equipped with a pressure transfer system are already known. Such an apparatus is for example described in French Publication No. 2,218,007 of Sept. 6, 1974.Pressure transfer then takes place by using a first calibrated relief valve equipped with a single control system by the pressure of a fluid intermediate between the pressures of the supply fluids of the receiving means. To increase the mechanical safety and reliability of the supply apparatus a second calibrated valve is preferably used which prevents too great a pressure transfer taking place.BRIEF SUMMARY OF INVENTIONThe present invention proposes a new pressure transfer system involving the use of only a single calibrated relief valve of a special type which is equipped however with a double control system. Two applications thereof are defined.The object of the first application is an apparatus for supplying pressurized fluid to two receiving means such as hydraulic motors constituted by two receiving means, a pressurized fluid source, a flow divider, a delivery pipe connecting the said fluid source to the inlet of the said flow divider, two main pipes whereby each of which is connected on the one hand to one of the receiving means and on the other to one of the two outlets of the flow divider, two auxiliary pipes whereof one connects one of the main pipes to one of the two inlets of a so-called pressure summation device, and the other connects the other main pipe to the other inlet of the said pressure summation device, a discharge pipe shunted in per se known manner to the delivery pipe and a calibrated relief valve positioned on the said discharge pipe.This relief valve has a double control system and comprises two control connections whilst a link links the discharge member of the pressure summation device to a first of the said control connections and a control pipe connects that portion of the discharge pipe located between the connection of the latter to the delivery pipe and the relief valve to the second of the said control connections.According to another application of the invention involving the same inventive principle as the first, the invention has for its object an apparatus for supplying pressurized fluid constituted by two pressurized fluid sources, two receiving means, two main pipes whereof one connects one of the fluid sources to one of the receiving means and the other connects the other fluid source to the other receiving means, a so-called pressure summation device equipped with two inlets and a discharge member, two auxiliary pipes whereof one connects one of the main pipes to one of the inlets of the pressure summation device and the other connects the other main pipe to the other inlet of the pressure summation device, at least one connecting pipe which connects the two main pipes, at least one shuttle valve arranged on at least one of the connecting pipes, a discharge pipe connected to the outlet of the said shuttle valve and a calibrated relief valve arranged on the said discharge pipe.This relief valve has a double control system and comprises two control connections whilst a link links the discharge member of the pressure summation device to a first of the said control connections and a control pipe connects that portion of the discharge pipe located between the connection of the latter to the delivery pipe and the relief valve to the second of the said control connections.In both applications the pressure summation device comprises an enclosure in two sections wherein is slidingly mounted a double piston having two portions of different cross-sections, whereby a first of these two portions slides in a first of the two sections and the second portion slides in the second section, whilst the two portions delimit in the said enclosure at least two separate chambers whereby each is provided with an orifice constituting the inlet, whereby the discharge member of the pressure summation device comprises the double piston itself and is mechanically coupled to the moving member of the relief valve.Preferably, the moving member of the relief valve is integral with the double piston of the pressure summation device.BRIEF DESCRIPTION OF THE DRAWINGSOther and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which by way of illustration show preferred embodiments of the present invention and the principles thereof and what are considered to be the best modes contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the scope of the appended claims.

Description

Claims

1. A hydraulic power supply system for supplying pressurized fluid to first and second fluid operated means such as hydraulic motors, said system comprising pressurized fluid source means, a flow divider having an inlet and first and second outlets, a delivery pipe connecting said pressurized fluid source means to said inlet of said flow divider, first and second main pipes each of which is connected on one end to one of the fluid operated means and on an opposite end to one of the outlets of said flow divider, a pressure summation device having first and second inlets, a first auxiliary pipe connecting one of said main pipes to said first inlet of said pressure summation device, a second auxiliary pipe connecting the other one of said main pipes to said second inlet of said pressure summation device, a shunt discharge pipe connected on one end to said delivery pipe, a calibrated relief valve positioned in said shunt discharge pipe and including a movable valving member mounted for movement between an open position in which flow through said shunt discharge pipe is permitted and a closed position in which flow through said shunt discharge pipe is prevented, said valving member being urged toward said open position by the pressure of fluid in the portion of said discharge pipe located between the connection of the discharge pipe to the delivery pipe and the calibrated relief valve, said pressure summation device including an enclosure defining first and second cylinder sections, a double piston having first and second piston portions of different cross-sectional area, said first piston portion being mounted for reciprocation in said first cylinder section and said second piston portion being mounted for reciprocation in said second cylinder section, said first and second piston portions having faces in first and second chambers of said enclosure, said first and second inlets of said pressure summation device being connected to respective ones of said first and second chambers, wherein said double piston comprises a movable output member which exerts a force which is indicative of the sum of the pressures supplied to said first and second inlets of the pressure summation device and means mechanically connecting said double piston to said movable valving member of said relief valve for urging said movable member with progressively increasing force toward its open position as the sum of the pressures in the inlets of said pressure summation device increases.

2. A supply apparatus according to claim 1, wherein the movable valving member of said calibrated relief valve is integral with the double piston of the pressure summation device.

3. An apparatus for supplying pressurized fluid to first and second fluid operated means, said apparatus comprising first and second pressurized fluid sources, a first main pipe connected on one end to said first pressurized fluid source and connected on an opposite end to said first fluid operated means, a second main pipe connected on one end to said second pressurized fluid source and connected on an opposite end to said second fluid operated means, a pressure summation device having first and second pressure input inlets and a movable output member, a first auxiliary pipe connected on one end to said first main pipe and connected on an opposite end to said first pressure input inlet of said pressure summation device, a second auxiliary pipe connected on one end to said second main pipe and connected on an opposite end to said second pressure input inlet of said pressure summation device, connecting pipe means extending between said first main pipe and said second main pipe, shuttle valve means mounted in said connecting pipe means, said shuttle valve means having a discharge outlet, a discharge pipe connected to said discharge outlet of said shuttle valve means, a calibrated relief valve mounted in said discharge pipe, said calibrated relief valve having a movable valving member movable between an open position and in which flow through said discharge pipe is freely permitted and a closed position blocking flow through said open position by the pressure of fluid in the portion of said discharge pipe located between the outlet of said shuttle valve and said calibrated relief valve, said fluid pressure in said portion of said discharge pipe being applied to said movable valving member by a control pipe connected to said portion of said discharge pipe on one end and on an opposite end to the body of said relief valve, said pressure summation device comprising an enclosure providing first and second cylinder sections, a double piston having first and second piston portions respectively mounted in said first and second cylinder sections, said first and second piston portions having faces in first and second chambers in said enclosure, said first and second inlets of said pressure summation device being connected to respective ones of said first and second chambers and means mechanically connecting said double piston to said movable valving member of said calibrated relief valve so that the sum of the pressures in said first and second inlets of the pressure summation device results in a force exerted by said double piston which is in proportion to the sum of said pressures urging said movable valving member toward said open position.

4. The invention of claim 3, wherein said movable valving member of said relief valve is integrally formed with said double piston of said pressure summation device.