Air cylinder

Claim 1

A cushioned air cylinder of tie-rod construction, comprising an opened ended cylinder barrel, a pair of end caps closing the ends of said barrel in a fluid-tight manner, means in said end caps for admitting air under super-atmospheric pressure to the barrel and for exhausting air therefrom, each end cap being provided with a pair of ports forming part of said means for admitting and exhausting air and which may be selectively blanked off by inserting screw plugs, said means further including first and second duct means in one end cap and third and fourth duct means in the other end cap, said first and third duct means communicating one of said ports in the respective end cap with the adjacent end of the cylinder barrel and said second and fourth duct meAns communicating the other of said ports in the respective end cap with the opposite end of the cylinder barrel by way of a conduit extending externally of said barrel between said end caps, a piston disposed within the barrel for reciprocating movements therealong under the influence of air under super-atmospheric pressure, a piston rod extending through one of said end caps and having its inner end fixedly secured to said piston, said piston having axially aligned male and female portions of which the male portion carries an annular seal, one of said end caps being provided with a female cushion bore and the other end cap being provided with a male boss carrying an annular seal, said bore and boss of said end caps interfitting with the male and female portions of the piston respectively and thereby providing plug-seal cushioning effect during operation of the cylinder.