Variable stroke balancing

An assembly, comprising:

• a piston,
• a transition arm coupled to the piston, a position of the transition arm being adjustable to vary a stroke of the piston,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions, and
• a control assembly coupling the balance member to the transition arm,
• wherein the control assembly includes a control rod having a first end region coupled to the transition arm and a second end region coupled to the balance member and
• wherein the control assembly includes a gear block receiving a nose pin of the transition arm, and a gear coupling the gear block to the first end of the control rod.

An assembly, comprising:

• a piston,
• a transition arm coupled to the piston, a position of the transition arm being adjustable to vary a stroke of the piston,
• a drive shaft coupled to the transition arm for driving the piston or for being driven by the piston,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions, and
• a control assembly coupling the balance member to the transition arm,
• wherein the control assembly includes a control rod with gear teeth, the control rod having a first end region coupled to the transition arm and a second end region coupled to the balance member, a longitudinal axis of the control rod being parallel to a longitudinal axis of the drive shaft.

An assembly comprising:

• a piston,
• a transition arm coupled to the pistons,
• a drive shaft coupled to the transition arm for driving the piston or for being driven by the piston,
• a radial position of the transition arm relative to a longitudinal axis of the drive shaft being adjustable,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions, and
• a control rod having gear teeth and a first end coupled to the transition arm and a second end coupled to the balance member such that movement of the control rod varies the position of the transition arm and the balance member, a longitudinal axis of the control rod being parallel to the longitudinal axis of the drive shaft.

An assembly, comprising:

• a piston,
• a transition arm coupled to the piston, a position of the transition arm being adjustable to vary a stroke of the piston,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions, and
• a control assembly coupling the balance member to the transition arm,
• wherein the control assembly includes a control rod with linear gear teeth, and a first gear and a second gear mating with the gear teeth.

An assembly, comprising:

• a piston,
• a transition arm coupled to the piston, a position of the transition arm being adjustable to vary a stroke of the piston,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions, and
• a control assembly coupling the balance member to the transition arm,
• wherein the control assembly includes a control rod with gear teeth having a first end region coupled to the transition arm and a second end region coupled to the balance member, a longitudinal axis of the control rod being parallel to a line extending from a center of motion of the transition arm to a center of motion of the balance member.

An assembly, comprising:

• a piston,
• a transition arm coupled to the piston, a position of the transition arm being adjustable to vary a stroke of the piston,
• a balance member adjustable relative to the transition arm to counterbalance the transition arm in varying positions,
• a control rod with linear gear teeth,
• a first gear mating with the gear teeth in a first section of the control rod,
• a second gear mating with the gear teeth in a second section of the control rod,
• a gear block attached to the transition arm and mating with the first gear such that linear movement of the control rod rotates the first gear to move the gear block in a first direction to change the stroke of the piston, and
• the balance member includes gear teeth mating with the second gear such that the linear movement of the control rod rotates the second gear to move the balance member in a second direction substantially opposite the first direction to counterbalance the transition arm.