Product Description:

The EA170-42100 is a mechanical limit switch produced by Danaher within the Snaplock Limit Switches series. As a position-sensing device, it translates shaft rotation into discrete electrical signals that let a control system detect end-of-travel or intermediate stops on conveyors, indexing equipment, or safety interlocks. The unit uses a reverse shaft to drive an internal cam, and it supports industrial conduit connections for straightforward mounting in automated machinery.

The enclosure accepts wiring through a 1-11½ NPT conduit entry so the housing can be sealed to standard rigid metal conduit. Internally, four independent contacts are arranged as 2 NO / 2 NC in Form Z, using silver-alloy butt tips to keep contact resistance low during repeated cycles. At 125 VAC, each pole can carry up to 20 A, enabling the switch to drive solenoids or relay coils directly. Mechanical actuation requires only 30 in-lb of input torque, and the total cam swing before the stop point is 37°, providing enough overtravel to confirm electrical changeover without damaging the mechanism. Recommended travel is 13°, with electrical tripping occurring after 10° and reset occurring at 8°, preserving the differential required for snap action.

The lever rotates only in the counterclockwise direction, which helps prevent accidental overshoot when the actuator returns. The position of the roller arm can be adjusted over a full 360° span, and the knurled hub locks at discrete 7° 30′ increments so multiple switches on a common shaft can be staggered precisely. The internal linkage uses a rocker-type mechanism that converts shaft motion into simultaneous but opposite contact movement, preventing contact timing from drifting during operation. Its silver-alloy butt contacts maintain dependable electrical switching, while the reverse-shaft arrangement transfers rotary input directly to the adjustable cam assembly.