Rugged enough for mining operations, these limit switches require a high actuation force, like heavy rocks moving on a conveyor. They open and close a circuit as quickly as a snap-acting switch but have a larger actuator for larger objects. The roller on the end of the lever arm reduces friction to prevent wear and tear on the switch. Rated NEMA 4 and 13 as well as IP67, these switches are protected from dirt, oil spraying, and temporary submersion.

To determine if you need a right or left actuation direction, stand facing where you'll put the switch. If objects will be passing to the right, you'll need a right actuation direction. If they'll be passing to the left, you'll need a left actuation direction.

Delay access to hazardous areas until conditions are safe; use these switches with machines that take time to stop after they are turned off. Mount the switch to the door frame and mount the key to the door so that the key is inserted into the switch when the door is closed. When the door is pulled, the key is held in place with 225 lbs. of force until the switch receives a signal from a time-delay relay, motion sensor, or position sensor (not included) that the machine’s motion has stopped. After the motion has stopped, the key can be removed from the switch, releasing the access door. They’re often used with machine guards. All have positive-force, normally-closed contacts that will open a circuit when the switch is actuated even if a spring fails or the contacts stick. They’re rated for protection from washdowns and temporary submersion.