A pneumatic actuator is powered by compressed air in order to move a valve, typically through 90 degrees of rotation or in a straight line. The return action can be driven by compressed air again (hence labeled Double Acting) or via a set of springs (called Spring Return/Single Acting). The mechanism to convert compressed air to torque is either a gear pair or a scotch yoke mechanism. Linear action does not require any mechanism. Sanyata’s rotary actuators combine rack and pinion and scotch yokes into one unified design and offer several unique features
For more detail:
Scotch Yoke Range
Rack and Pinion Range