Oscillating Actuators

Rollnut Oscillator

The Rollnut Oscillator is an actuator that provides a reciprocal motion where one revolution of the rotating shaft (or nut) equals one complete cycle.

Designed for maximum performance, the Rollnut Oscillator provides high linear speeds at relatively low rotary speeds for reduced noise and wear. Stroke, profile and shaft diameter are custom designed to suit the application. Profiles can be Simple Harmonic Motion (SHM), cycloidal or specially designed to incorporate dwells or other features.

Centralizing bearings in the nut resist sideloads and provide ease of movement. Shaft material is either alloy steel hardened to approximately 55 Rc or stainless steel hardened to approximately 45 Rc.


The tapered nose of the bearing-mounted roller tracks in a special type groove machined into the shaft. The nose angle is selected for maximum rolling efficiency.

pic1 pic2

Various nut configurations are possible. Fixed housing can often be made into a rollnut by adding a roller.

For high loads, high speeds and/or extended life, twin (multi-) track units are recommended. This arrangement minimizes roller slippage and wear by allowing each roller to rotate continuously in a constant direction. Multi-track units are capable of high thrust loads. A split nut can also be used for minimum backlash requirements.