Wednesday, January 14, 2015

Features of the ROTEX DRS Scotch Yoke Actuator

Actuator Modules 
  • ROTEX actuator spring modules and pneumatic modules can be removed, swapped, rebuilt, or reinstalled on the frame module without disassembling the frame module. No need even to remove top cover of frame module, because all bolting for removal of the modules is external. 
  • Actuators can easily be changed in the field from fail close to fail open by just swapping the positions of the spring and pneumatic modules. No need to dismantle the frame cover or cylinder assembly. 
  • Actuators can be modified from double acting to spring return easily in the field by adding a spring module. 
Springs are lifetime lubricated and epoxy coated.
  • Springs are pre-compressed inside their welded spring modules for safety and ease of use.
  • Pneumatic cylinders are lined with hard chrome plating. Smooth to eliminate wear of piston seals, the surface is very hard, for long life. 
  • Inside the pneumatic module, dual oversized tie rods are protected from external corrosion. Where the tie rods pass through the piston head, ROTEX has improved the design by providing a slide bearing, where most designs don’t. This bearing is important to help maintain alignment and assure smooth operation. 
Frame Module
  • Inside the frame module, the yoke is supported by life time lubricated bearings. Needle roller bearings ensure the most efficient torque transmission. 
  • Extra heavy duty travel adjustment bolts allow for +/- 10% adjustment of the 90 degree stroke. The area of contact is large, to withstand the impact forces. 
  • The yoke thrust pin is made of case hardened steel to resist wear. 
  • The piston shaft is supported on each side of the frame module by solid bearings that ensure proper alignment and smooth operation. 
  • Each piston shaft of the ROTEX DRS is equipped with two Flexijoints. These specially designed joints compensate for movement and changes in alignment to reduce internal stresses and increase output torque. 
  • The thrust transmitted through the Flexijoints ensures no side thrust on the cylinder walls and bearings. 
Unique Sealing Features
  • Piston seal is ROTEX X design. Flexibility of the sealing material reduces friction, prevents leakage, and extends actuator life. The X shaped seal is wear compensating, and the unique shape of the seal retains the grease for longer periods. The piston is guided by a PTFE thrust bearing, which helps keep the piston centered, and seal wear to a minimum. 
  • The tie rod seal is also of the ROTEX X design. Old fashioned O-rings are replaced by these flexible, low friction, resilient seals to reduce the failure rate of tie rod seals. Also reduces the wear and tear to the tie rods themselves. 
  • ROTEX has also replaced the standard O-ring of the shaft seal. In this position, we provide a proven V-seal design. This self-energized, wear compensating seal guarantees low hysteresis and minimum friction. Like the X seal of the piston and tie rod seals, the inherent shape of the V-seal helps keep the grease where it needs to be. 
Optional Hydraulic Override
  • ROTEX DRS actuators may be ordered with an optional hydraulic override, or the override may be retrofitted to an existing actuator. 
  • The override is fitted into the spring cartridge, to keep the overall dimensions of the actuator and override to a minimum. Can withstand up to 2,000 psi hydraulic pressure.
  • Easy to operate.
  • Special Z seal ensures zero leakage and extended life.


  1. Is there any further reading you would recommend on this?

    About Bl Pneumatics

  2. In our steel plant, DRS A 0350 double acting pneumatic actuator is failing due to your pin shear/bend and the slots are getting unevenly worn out.