Abstract: A method and apparatus for braking a rotating element including a reversible eccentric ring or axial piston pump which may be selectably operatively connected to a rotating element. When either pump is configured to compress ambient fluid into a reservoir, the compressive resistance is transmitted to the rotating element, braking it. When either pump is configured to expand fluid from the reservoir, the resultant torque generated is transmitted to the rotating element, driving it. The invention provides mechanisms for rapidly configuring either pump to compress or expand fluid, and for adjusting pump displacement, respecting a user's demand.

Abstract: An input shaft includes a cam configured to have a variable diameter profile. An oscillating arm tracks the cam profile. Oscillating motion of the arm is converted by roller clutches back to rotary motion. Speed variation is accomplished by moving the arms axially so that they contact the cam at points of varying cam diameter. The cam is configured to eliminate torque surges at all speed ratios, resulting in smooth delivery of torque under all conditions. An appropriate cam surface providing this result is disclosed.