IMI STI has introduced the Zero Backlash (ZB) Scotch Yoke Mechanism. Designed for use with the entire range of RT series products, the Zero Backlash aims to improve performance and solve other issues associated with existing technologies.
Historically, quarter turn valves have been used almost exclusively for on–off applications. More recently however, the need for use in regulation processes is increasing.
The majority of pneumatic and hydraulic actuators use scotch yoke technology to transform the linear piston movement into a rotary one. Gaps between the sliding block and the scotch yoke slot inevitably have a negative influence on both precision and the functional dynamics (hysteresis, dead band, small step response, etc). Throughout the operative life of the actuator, this inaccuracy becomes permanent and will consistently worsen.
