I'm looking for some input on a problem I'm having with some long air cylinders and two hand safety.
Right now I'm using a two hand safety relay, and corresponding pushbuttons. I am energizing a two position detented air valve to shift an actuator back and forth. The power to the air solenoid coils goes through the contacts of the safety relay.
Problem is, with a detented valve, once the valve shifts into position, the clyinder will remain moving even if the safety relay is shut off (operator lets go of the pushbuttons). I could use a 3 position exhaust center valve, but then once the motion is done and it is safe for the operator to let go of the buttons, the air pressure is no longer holding the actuator in position.
Is there a solution that doesn't involve a complicated (expensive) safety relay system with bypasses and safety switches?
Basically the air actuator needs to move only when the two hand safety is pressed, but needs power to hold the actuator in position once its switch is made, like a magnetic band cylinder switch on the extended position of an air cylinder.
Right now I'm using a two hand safety relay, and corresponding pushbuttons. I am energizing a two position detented air valve to shift an actuator back and forth. The power to the air solenoid coils goes through the contacts of the safety relay.
Problem is, with a detented valve, once the valve shifts into position, the clyinder will remain moving even if the safety relay is shut off (operator lets go of the pushbuttons). I could use a 3 position exhaust center valve, but then once the motion is done and it is safe for the operator to let go of the buttons, the air pressure is no longer holding the actuator in position.
Is there a solution that doesn't involve a complicated (expensive) safety relay system with bypasses and safety switches?
Basically the air actuator needs to move only when the two hand safety is pressed, but needs power to hold the actuator in position once its switch is made, like a magnetic band cylinder switch on the extended position of an air cylinder.