Piston joint

A method of reducing side load in a double ended member, the double ended member including first and second elements arranged for linear motion along an axis of the double ended member, the method comprising:

• providing a joint located between the first and second elements, the joint including an outer member configured for movement relative to the first and second elements along a first axis perpendicular to the common axis, the outer member defining first and second parallel flat sides, each flat side defining a plane perpendicular to the common axis, the outer member defining an opening for receiving a drive arm, and an inner member mounted within the outer member for rotation relative to the outer member about a second axis perpendicular to the first axis and the common axis and for movement relative to the outer member along the second axis, the outer member being restrained from movement along the second axis, the inner member defining an opening for receiving the drive arm, and
• transferring load between the first and second elements and a drive arm mounted to the joint through two opposed surfaces of the outer member.