Shaft Signalling Key.
A colliery shaft signalling key, known as a knocker box. Made by Davis of Derby.
Made from iron and cast iron. Size 6″ x 4″ x 2″ inches.
These signalling keys were mounted onto the control panel in an upright position (as seen in the image left) and used to signal from pit-bottom to the bank to inform the surface if men were being transported up the shaft and vice versa.
Underneath the bottom lip of the cover is an arm, you place your fingers under and pull forward the number of times to signal eg 1, 2, 3 or 4 – men, supplies, turn the pit etc.