Colliery Lock-Out Key.
A colliery lock-out key – Lock out box. Made by the Communication & Control Engineering Company. Model PK-190s.
Made from metal, plastic and rubber. Size 10″ x 5″ x 3″ inches. Date 1980’s.
These lock-out boxes were connected with each other by long lengths of wire and cable and bolted to the framework of conveyor belts at intervals of approximately 50 yards. If the conveyor belt had to be stopped for any reason such as for safety or maintenance, you had to pull the wire, or if you were close to the box just turn the red switch.
The lock-out box that was activated would “lock out” the power to the conveyor, a red light would show on that box and the conveyor belt could not be restarted until that particular box was located and manually reset. The red light would glow in the dark to show which box was locked out.