Limit switch PSBM1 K99 PX21 with latching A37-C646

Limit switch with latch and reset by pulling the ring

This is an emergency pull‑cord type switch, designed for fast and reliable stopping of a machine or equipment by pulling a rope or cable. The PSBM1 K99 PX21 (A37-C646) version has 1 breakable circuit and 2 closed contacts, meaning that when activated it opens one circuit while simultaneously closing another – ideal for signalling a stop condition or a control lockout.

Mechanical latching prevents accidental re‑starting – the switch stays in the “stopped” position until it is manually reset by pulling the ring. This is a key safety feature in workplaces where a clear, physical verification of the stop state is required before re‑energising.

Installation is simple – the device is mounted permanently, and the cord is routed to a point where the operator can easily reach it in an emergency. It requires no power supply and operates purely mechanically, making it reliable even when there is no voltage or during electronic failures.

Applications: production lines, presses, conveyors, CNC machines, high‑torque equipment – anywhere a quick and indisputable stop is needed. The latching version is especially recommended where regulations or safety standards demand physical confirmation of reset.

There are no electronic components or sensors – everything relies on pure mechanics. This eliminates failures caused by over‑voltages, interference, or moisture. It operates in industrial conditions without additional protection.