Spring Cylinder Rotary Actuator

The MASCOT Spring Cylinder Rotary Actuator combines high torque and pneumatic stiffness with excellent throttling capabilities. These characteristics are designed into a lightweight, rugged and compact assembly, making the MASCOT rotary actuator the foremost choice for quarter turn applications. The MASCOT rotary actuator is designed to operate the DISKFLO high performance butterfly valve, the VFLO V-notch ball valve, or other applications requiring precise rotary motion. MASCOT pneumatic and electro-pneumatic positioners are available for throttling applications.

The actuator, cylinder and MASCOT positioner are designed for supply pressures up to 150 psi, making very high torques attainable. The actuator uses a rocking piston for direct conversion of linear motion to rotary motion. The rocking piston assembly combined with a splined shaft and lever eliminates lost motion.

Spring Cylinder Rotary Actuator Features

Accepts up to 150 psi air supply

  • Achieves higher torques
  • Obtains stiff piston positioning
  • Permits higher DP limits on valve

Rocking piston

  • Provides direct connection to shaft
  • Assures zero lost motion between actuator and valve
  • Utilizes fewer parts

Splined shaft and lever

Allows zero lost motion

Compact, lightweight, rugged

  • Permits easy maintenance
  • Installs in limited space applications
  • Easily meets seismic requirements

Low friction bearings

  • Provide millions of cycles with minimal wear
  • Combined with direct linkage, provides very low hysteresis

Field reversible

  • Requires no extra parts
  • Permits fast, easy field reversing
  • Requires no change of spring action

Fail-safe spring

Moves actuator to failure position without pressure assistance

Air-purged, fully enclosed transfer case

  • Prevents corrosion of linkage
  • Ensures safe operation
  • Contains external position indicator
  • Allows four mounting positions without retubing, changing or adding parts

Stroke stops

Allow both ends of stroke to be adjusted

The MASCOT rotary spring cylinder actuator also capitalizes on established features of other MASCOT actuators:


  • Minimizes requirements for stocking spare parts
  • Reduces inventory costs
  • Uses identical parts in differing rotary actuator sizes
  • Utilizes many MASCOT linear actuator parts

Spool-type four-way Positioner

  • Provides high-performance modulating positioner control
  • Ensures ease of calibration and maintenance due to fewer parts