PERFECT WEIGHT and FORCE BALANCE

Very low friction adaptation of the scotch yoke type mechanism

We've always had a great actuator design but could not economically expand the Rack & Gear^TM torque output

Thus, the Flat Yoke actuator was developed.

Compatible with all of the same options as offered on the R&P actuators, the Flat Yoke adds fully accessible bi-directional travel stops and a modular construction with far greater torque output.

Why did we call it a Flat Yoke instead of the more common name of scotch yoke? Well, precisely because the scotch yoke name is synonomous with a generic, outdated (by the Flat Yoke) design and because the Flat Yoke design is truly unique with extremely beneficial features.

We do not wish to disparage scotch yoke actuators, which are tried and tested, but we believe that users of scotch yoke actuators are satisfied with their performance only because they have never been offered anything better. Consider the act of mounting the SY actuator. Typically they are much heavier on one end than the other. Where's the balance point. How much time is spent aligning the actuator and valve shaft? Too much!

Consider also that SY actuators inherently are high friction with components sliding against one another and with components being subject to extremely high side loading. Wear occurs, but is expected, because that's what it is ..

Also SY actuators generally contain numerous dynamic seals, any one of which may fail causing the necessity of removing the actuator from the valve followed by complete disassembly for repair. Users expect seal failure and the need to rent lifting equipment while several workers are assigned to detach the actuator from the valve stem - a not always easy job that may incur valve damage. Users also expect to pay exhorbitant prices for proprietary seals and .. plant revenue may be on pause while all of the related cost is being incurred.

Perhaps user expectations are simply too low! Are your's?

By contrast to SY designs, the Flat Yoke design is weight and force balanced. This means they are easier to install while requiring less concern regarding pipe stress from overhanging SY actuators.

Additionally, most of the seals common to SY actuators have been removed. This is made possible by the unique body slots which absorb 100% of the side loading forces that would be applied to the piston rod in the SY design. Being able to terminate the piston rod at the yoke slot allowed placement of pistons and spring modules on diagonally opposite ends of the body module. Pushing in opposite directions on dual yoke arms negates the massive force loading that occurs on SY shaft bushings. Flat Yoke shaft bushings see zero loading and can be expected to last forever.

Because springs are placed inward of the pistons, no inward seals are required and the tie rod design enables on site removal of the end cap, cylinder and piston o-ring for reduced labor, no rented lift equipment and rapid return of process revenue.

One more thing, Flat Yoke actuators are covered by the same 3 year performance warranty as applicable to our Rack & Gear actuators.

Raise your expectations ... specify QTRCO Flat Yoke actuators.

FS Series, 1/4 Turn Flat Yoke Actuators

PERFECT WEIGHT and FORCE BALANCE

Very low friction adaptation of the scotch yoke type mechanism