Pressure fluid controlled reciprocating mechanism

Claim 1

In a work-producing mechanism having a hollow housing defined by first and second ends and connecting sidewall means and an elongate work producing member slidably supported in said housing, with a first portion of said member projecting outwardly through an opening in said first end, the improvement for causing said member to automatically reciprocate between first and second positions in said housing by first, second and third fluids, said first fluid being pressurized by means exterior of said housing that is in communication with the interior of said housing through a first passage in said sidewall, said means on demand supplying said first fluid to said housing at a first pressure, back pressure means that maintain said second fluid in said housing until a second pressure is reached on said second fluid whereupon said second fluid is discharged from said housing, said second pressure being less than said first pressure, said improvement comprising: a. potential energy generating means that at all times tend to maintain said member in a first position where said first portion is of maximum length; b. a cylindrical sleeve slidably supported for longitudinal movement in said housing, said sleeve having first and second ends and an inner cylindrical surface, with said sleeve extending around said member in said housing, and said sleeve having at least one transverse opening therein that is at all times in communication with said first fluid passage; c. a ring-shaped valve member that projects outwardly from said member and is at all times disposed in said sleeve and in communication with said opening therein; d. a ring-shaped valve seat that extends inwardly from said second end of said sleeve, with the external diameter of said valve member greater than the internal diameter of said seat, and said valve member and valve seat when said elongate member is in said first position capable of being in sealing contact; e. first means for maintaining said third fluid at a third pressure in communication with said first end of said sleeve, said third pressure being less than said first pressure, said first fluid after said member has moved to said first position and said valve member and valve seat are in sealing contact exerTing a sufficient force on first and second ring-shaped areas defined on said valve member and valve seat as to move said elongate member and valve member towards said second position against the force offered by said potential energy generating means and the force exerted by said second fluid on a third ring-shaped area defined on said valve seat, with said force exerted by said second fluid on said third area being greater than the force exerted by said first fluid on said second area as the movement of said elongate member towards said second position takes place to maintain said valve member and valve seat in sealing contact, and the force exerted by said first fluid on said second area being greater than the force exerted by said second fluid on said third area after said second position is reached to break the seal between said valve member and valve seat to momentarily allow the pressure on said first fluid to drop to said second pressure whereupon said potential energy generating means drives said member from said second to said first position at high velocity, with said sleeve and valve seat thereafter moving towards said first end for said valve seat to seal with said valve member due to the force exerted by said second fluid on said third area being greater than the force exerted by said first fluid on said valve seat and the force exerted by said third fluid on said first end of said sleeve.