Development of a spring loaded micro-pivot bearing

Ratchet and pawl mechanisms have been used for centuries in timing escapements and many other devices. As these devices are driven to ever-smaller dimensions, friction and other micro-forces become highly influential on device operation and reliability. This paper describes the design and assembly of a zero-friction, spring-loaded pivot bearing for possible replacement of the standard spring and rotational bearing in ratchet and pawl mechanisms. Three issues are discussed: development of a closed-form solution that relates bearing geometry and material properties to rotational spring rate, a macro-scale pivot bearing prototype to validate the closed-form solution, and the use of a micro-assembly workstation to assemble an ultra-miniature bearing comprised of micro-scale components.