Spring-return
scotch yoke actuator.
Our JAG swivel drives work with a yoke drive system (also yoke kinematics or swing arm system). With the same piston diameter as rack and pinion drives, this system offers significantly higher torques when opening and closing due to the longer lever.
The torque curve corresponds perfectly to the variable torque requirement of a ball valve or a butterfly valve.
As a result, under certain circumstances, the drive with the yoke system can be selected one size smaller than the drive with the rack and pinion system. This reduces the costs for purchase, compressed air consumption as well as installation dimensions and weight.
Highlights
Long lever for high torques thanks to yoke kinematics (rocker)
Double end position adjustment - 2 positions (open - closed)
Sealing solutions from -50°C to +160°C (depending on the sealing material).
EN15714-3 interface direct mount fittings - double hole pattern and octagon ISO5211
EN15714-3 interface direct mounting pilot valves NAMUR
EN15714-3 interface direct mounting position indicator and - controller
Modern actuator
Power transmission
By applying pressure to piston A, the force is transmitted via roller B to control yoke C, which is firmly connected to shaft D and thus also to the valve shaft.
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The lever L is longest at 0° and develops the maximum closing force (as required for a ball valve and a butterfly valve). The lever is shortest in the middle position and becomes very long again in the open position (as required by the ball valve).
Torque curve
A characteristic of yoke drives is the up to 50% higher torque in the end positions compared to rack and pinion drives.
The torque curve of the single-acting JAG yoke drive shows an increasing torque in the spring return (safety position) where safe function is really required.
Function
3/2 monostable with spring return
(optionally open or closed without current)
The drive opens anti-clockwise when current is applied to the coil and vents the inner air chamber (see left picture).
The drive closes by rotating clockwise without applying current to the coil and vents the outer air chambers (see right picture).