Ram with cushioned piston stroke

Claim 2

In a ram including a cylinder, a piston within the cylinder, and an end wall closing off one end of the cylinder, a construction providing for cushioning of the piston when it moves in one direction to a position adjacent said end wall and permitting rapid return movement of the piston when moved in the opposite direction, comprising an annular groove extending about the piston including one side which is adjacent and an opposite side which is remote from said end wall, a ring mounted within said groove with the periphery thereof disposed radially outwardly of the periphery of the piston and against the inside of the cylinder, said ring being loosely mounted in said groove whereby it is axially shiftable within the groove, fluid passage means connecting the end of the piston which faces said end wall of the cylinder with said groove, and a port in the ram cylinder for the supply and exhaust of fluid to said ram communicating through said groove and said fluid passage means with said end of the piston when said piston is adjacent said cylinder end wall and said ring is against said one side of the groove, said port being closed off from said end of the piston with said ring against said opposite side of the groove.

Claim 3

The ram of claim 1, wherein said piston has a recess indented inwardly from its said end which faces said end wall, and said fluid passage means includes said recess.

Claim 4

The ram of claim 1, which further comprises metering passage communicating with said end of said piston and joining with the side of the piston at a point located toward the piston''s opposite end from the location of said groove.

Claim 5

The ram of claim 3, wherein a fluidtight sealing annulus is provided which extends about said piston and which is located toward said opposite end of the piston from the point where said metering passage means joins with the side of the piston.

Claim 6

A double-acting ram as claimed in claim 1, which includes an opposite end wall closing off the opposite end of the cylinder, said piston having an end opposite its said one end which faces said opposite end wall, another annular groove extending about the piston adjacent said piston''s opposite end, said other groove including one side which is adjacent and an opposite side which is remote from said opposite end wall, another ring mounted within said other groove with the periphery thereof disposed radially outwardly of the periphery of the piston and against the inside of the cylinder, said other ring being loosely mounted in said other groove whereby it is axially shiftable within said other groove, a second fluid passage means connecting said opposite end of the piston with said other groove, and another port in the ram cylinder for the supply and exhaust of fluid to said ram, said other port communicating through said other groove and said second fluid passage means with said opposite end of the piston when said piston is adjacent said opposite cylinder end wall and said ring is against said one side of the other groove, said port being closed off from said opposite end of the piston with said ring against said opposite side of said other groove.

Claim 7

The ram of claim 5, which further comprises a fluidtight sealing annulus extending about the piston at a location intermediate said first and said other groove.

Claim 8

The ram of claim 6, which further comprises metering passage means communicating with said opposite end of the piston and joining with the side of the piston at a point located between said annulus and said other groove.