Double rod end cylinder with split ring coupling

A fluid-actuated cylinder, comprising:

• an elongated cylinder body having first and second ends and defining an internal piston chamber;
• an elongated unitary piston rod moveably disposed within the body and projecting outwardly from at least one end of the body, the piston rod including a circumferentially extending first groove in its outer surface along the length of the piston rod;
• and
• a piston assembly rigidly coupled to the piston rod in surrounding relation therewith and in sealing engagement with the cylinder body to define first and second fluidly-separated chamber portions at opposite ends of the cylinder body, the piston assembly including a ring-shaped piston, a split ring coupling with predetermined linear expansion properties and fasteners rigidly and securely fastening the split ring coupling to the piston;
• the split ring coupling located in the first groove and having an interference fit with opposing sidewalls of the groove in the piston rod such that the split ring coupling is rotationally and axially fixed with respect to the piston rod and the piston rod is prestressed.

A method for assembling a fluid-actuated cylinder, comprising the steps of:

• providing an elongated cylinder body having first and second ends and defining an internal piston chamber;
• providing a unitary, elongated piston rod including a circumferentially extending first groove in its outer surface along the length of the piston rod;
• rigidly coupling a piston assembly to the piston rod, the piston assembly including a ring-shaped piston, a split ring coupling with predetermined linear expansion properties and fastening means rigidly and securely fastening the split ring coupling to the piston;
• the coupling step including reducing the temperature of the split ring coupling with respect to the piston rod so that the split ring coupling can be located in the first groove, locating the split ring coupling in the first groove, and then equalizing the temperature of the split ring coupling and the piston rod such that the split ring coupling axially expands into an interference fit with the first groove in the piston rod such that the split ring coupling is rotationally and axially fixed with respect to the piston rod and the piston rod is prestressed;
• and
• locating the piston rod and piston assembly within the cylinder body with the piston assembly in sealing engagement with the cylinder body to define first and second fluidly-separated chamber portions at opposite ends of the cylinder body.