Piston assembly

A method of varying the output volume of a piston assembly, comprising:

• providing a piston assembly including a piston rod configured and arranged for linear motion and a transition arm coupled to the piston rod, the transition arm including a nose pin, an axially stationary support to which the transition arm is mounted, a bearing coupled to the nose pin, a housing that houses the bearing, and a member defining a channel, the bearing element being received in the channel, and
• mechanically exerting a force on the housing to move the housing and bearing along the channel, wherein the bearing element moving along the channel results in a position of the nose pin being adjusted.

An assembly, comprising:

• a transition arm coupled to a stationary support, the transition arm including at least one piston arm,
• at least one double-ended member, the double-ended member coupled to the piston arm, and
• a member coupled to the transition arm, a position of the transition arm relative to an axis of rotation of the member being adjustable to vary the output volume of the double-ended member to zero, the member defining an arc-shaped guide for guiding movement of the transition arm when the position of the transition arm relative to the axis of rotation of the member is adjusted.

A method, comprising:

• providing, a piston assembly including at least two double-ended members, a transition arm having at least two piston arms, each double-ended member coupled to one of the at least two piston arms, and a stationary support to which the transition arm is mounted, and
• moving the transition arm along an arc-shaped guide to vary the output volume of the piston assembly during operation of the piston assembly.

A method of varying the output volume of a piston assembly, comprising:

• providing a piston assembly including a piston rod configured and arranged for linear motion and a transition arm coupled to the piston rod, the transition arm including a nose pin, a stationary support to which the transition arm is mounted, a bearing element coupled to the nose pin, a member defining a channel, the bearing element being received in the channel, and a gear coupled to the bearing element, and
• rotating the gear to move the bearing element along the channel, wherein the bearing element moving along the channel results in a position of the nose pin being adjusted.