Energy conserving directional valve-cylinder combination

Claim 1

An energy conserving directional valve-cylinder combination comprising: a fluid motor including a cylinder, having one cylinder end blind including fluid supply and exhaust means provided therein, and another cylinder end open and adaptable to be closed partially by a rod end closure, said rod end closure including fluid supply and exhaust means provided therein and a central piston rod opening with a seal, said cylinder means including internal diameter tubular portions of large and small coaxial diameters separated by a shoulder substantially midway thereof, with said larger diameter portion initiating at the cylinder open end while said smaller diameter portion continuing inwardly from said shoulder until it meets said blind end provided with a closure, atmospheric vent means in said cylinder adjacent said shoulder, a differential diameter piston means including coaxial piston rod attached thereto and protruding from said cylinder rod end closure, said piston means having an elongated smaller diameter piston at one end and a short larger diameter piston with said rod at the other end slidably received inside said cylinder means with said small piston entering said small diameter cylinder portion and said larger piston entering said large diameter cylinder portion and capable of axial movement in response to pressurized fluid supplied thereto by shuttling within cylinder confines controlled by said rod end closure at one piston rod extended position and said cylinder shoulder at the other piston rod retracted position, seals in said pistons, means for actuating said fluid motor to perform work by said piston rod when coupled to a load during said position change of said differential diameter piston means inside said clyinder means, said actuation caused by said pressurized working fluid entering and leaving said fluid supply and exhaust means at each cylinder end alternatingly feeding said one cylinder end while simultaneously exhausting said otheR cylinder end, or vice versa as controlled by a directional valve closely coupled with said cylinder and capable of being selectively controlled between a first valve open position wherein fluid communication is permitted between a source of the pressurized working fluid and said cylinder blind end for pressurization of said small diameter piston with full pressure urging said piston rod extension under load, and a second valve closed position allowing energy extraction from fluid exhausted from said cylinder blind end by redirecting said working fluid in tandem from said blind end toward said cylinder open end provided with said rod end closure for pressurization of said larger diameter piston urging said piston rod retraction under load, said energy conserving tandem directional valve comprising a multiported longitudinal valve housing having first and second ends interconnected by a bore extending therethrough, said bore having a first diameter portion adjacent said first end extending inwardly therefrom toward said second end, a second diameter portion adjacent said second end extending inwardly therefrom toward said first end and a third diameter portion interconnecting the innermost ends of said first and second diameters, said first and second diameter portions having larger diameters than said third diameter portion, including shoulders at interconnection of said diameters with a first shoulder facing said housing first end and a second shoulder facing said housing second end, said housing further including at least three perpendicular ports extending through said housing and communicating with said bore extending therethrough, one of said ports comprising a first fluid supply port communicating with said first diameter portion adjacent said first housing end and adaptable to be connected to said working fluid source, another of said ports comprising a second fluid port communicating with said third diameter portion and adaptable to be connected to said cylinder blind end, the remaining port comprising a third fluid port communicating with said second diameter portion adjacent said second housing end and adaptable to be connected to said fluid supply and exhaust means of said rod end closure covering said cylinder open end, said second bore end closed by an end cap provided with a central opening therethrough comprising a main valve exhaust port, said second and said third ports interconnected with said cylinder, said first bore end receiving slidably an elongated stem with a piston at one end and a counterbored smaller diameter portion at the other end, said piston having a close sliding fit with the housing and having a seal received slidably inside said first diameter portion with piston head including an end face, a second seal in said stem received inside said first diameter portion and spaced along said stem from said piston adjacent said first shoulder with seal diameter less than the diameter of said piston but greater than said third diameter portion, a third seal in said stem having a diameter greater than said third diameter portion but less than said second diameter portion and located on a stem diameter portion received in said second diameter portion adjacent said second shoulder, a final seal on said opposite stem end adjacent said counterbored portion sized to permit close sliding fit inside said exhaust port of said end cap, said stem being selectively shifted between a first position wherein said fluid communication is permitted between said first and second ports but precluded from entering said third port by said third seal firmly seated against said second shoulder while simultaneously allowing fluid communication between said third and said exhaust ports, and a second position wherein fluid communication is permitted between said second and third ports while having said second seal firmly seated against said first shoulder to preclude fluid communication between said first and second ports and also having said final seal engaged inside Said main valve exhaust port to preclude fluid exhaust into the atmosphere, said stem further including a small fluid passage extending therethrough from said piston face for selectively allowing fluid flow from said first diameter portion through said fluid passage and outwardly from said end face, said second port connected to said fluid supply and exhaust means of said cylinder blind end and said third port to said cylinder rod end closure supply and exhaust means, a solenoid valve operator disposed at said first bore end of said housing, said operator having a plunger disposed generally coaxial with said stem and axially movable selectively in an operative relationship with solenoid energization between an open position spaced from said end face of said piston and defining a fluid cavity therebetween and a closed position in blocking engagement with said small passage at said end face, wherein when said plunger is in said closed position said stem is retained in said first position by fluid entering a first annulus formed between said stem and said first diameter portion provided with piston side, opposite said piston face end, exposed to said fluid with a force large enough to maintain said third seal firmly seated against said second shoulder when said stem is in said first position with said valve open to full pressure of the working fluid feeding said cylinder blind end via said second port to urge said piston rod into extended position while said main valve exhaust port is open to atmosphere, and wherein when said plunger is in said open position said stem is shifted to said second valve closed position by fluid entering said cavity through said passage in said piston end face and acting against said piston head exposed to said cavity with a force large enough to maintain said second seal firmly seated against said first shoulder while allowing