The fit between the sensor piston and the bore must be such as to prevent a false signal being received by the blocked port. The piston may utilize seals to prevent this possibility and allow more piston to bore clearance. If this is, the method used care must be taken that when the seals pass over the ports that the ports do not cut the seal creating a leak path.
Care must be taken so that contamination from machine chips and finds do not interfere with sensing.
PROXIMITY SWITCH SENSING This type of sensing uses commercial proximity switches or reed type switches to signal clamp position directly to the control input. These type of switches do not require contact with the cam or position rod, but the customer must maintain the correct clearance as recommended by the switch manufacturer. Basic Requirements Sensor cam must have enough surface area so that it can indicate a clamp condition for variation in part thickness tolerance. Clamp adjustment must be made to each clamp at time of set up.
Hydraulic Clamping Fundamentals Rev - D
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