Piston locking device for double acting hydraulic cylinder

A double acting hydraulic piston cylinder assembly comprising:

• an elongated cylinder having a cylindrical wall, first and second opposite cylinder ends, and a cylindrical bore extending longitudinally therethrough;
• first and second cylinder closure means sealingly fitted within said first and second cylinder ends and each having a rod receiving opening extending therethrough in an axial direction with respect to said cylinder;
• an elongated piston rod extending through said rod receiving openings of both of said first and second closure means and having first and second opposite rod ends protruding axially beyond said opposite ends of said cylinder, said rod being longitudinally slidable within said rod receiving openings for reciprocating longitudinal movement therein;
• a piston within said cylinder having an outer cylinder surface in close proximity to said cylindrical wall of said cylinder and having a central axial opening surrounding said piston rod;
• sealing means between said outer cylindrical surface of said piston and said cylindrical wall of said cylinder;
• said rod having an annular rod groove extending therearound and a radial bore in communication with said rod groove and extending radially inwardly therefrom;
• said piston having an annular piston groove formed therein within said central opening, said piston groove being in registered alignment radially outwardly from said rod groove;
• said piston having an access opening therein, said access opening commencing at an outer end located at said outer cylindrical surface of said piston and extending inwardly within said piston to an inner end in communication with said registered annular piston and rod grooves said access opening having a tangential wall portion which is in approximate tangential relation to said annular piston groove;
• a metal retainer wire having a solid cross-sectional configuration and being within said registered annular piston and rod grooves and extending around said piston rod, said retainer wire having a sufficiently large cross section to extend within both of said piston and rod grooves whereby said retainer wire is in communication with said piston and rod grooves and holds said piston against axial sliding movement with respect to said piston rod;
• said retainer wire having first and second ends, said second end extending within said radial bore in said rod, said first end of said retainer wire being positioned within said access opening and engaging said tangential wall portion of said access opening.