King Hook

A safety detaching hook fitted between a mine cage and its winding rope, designed to release the cage automatically if it was ever wound too far and struck the headgear.

Historical usage

Sources differ on the inventor's identity: one account credits a 'Tom King', while another identifies him as John King of Pinxton, Derbyshire, who patented his detaching hook in 1867 after it was first used at Pinxton Colliery. Whichever King it was, the device spread across British collieries and beyond, and is credited with saving a great many miners' lives over the decades that followed.

How it worked

The hook connected the cage to the winding rope through a mechanism held closed by a copper pin. If the cage was wound past its normal stopping point — an 'overwind' — a fixed catch plate at the top of the headgear broke the pin, releasing a sprung claw that let the hook detach from the rope; the cage itself was then caught and suspended in the headgear rather than being hauled into the winding wheel or falling back down the shaft. The hook could be reset and reconnected to the rope by hand once the fault was cleared.

Why it was used

An overwind — caused by a moment's inattention at the winding engine, or a mechanical fault — could otherwise be catastrophic: a cage hauled over the winding wheel could spill miners directly into the machinery, or the rope could part and drop a fully loaded cage back down the shaft. A reliable automatic detaching mechanism turned a near-certain fatal accident into a recoverable equipment fault.

Risks & limitations

The device depended on its copper pin and catch mechanism being correctly set and well maintained; a badly adjusted or worn hook could either fail to release during a genuine overwind or release unnecessarily during normal winding, each with its own real safety and operational consequences.

Related terminology

Cage, Headgear / Headframe

Sources

1. (secondary) Headstocks — Mining Heritage
2. (secondary) More Notes on the Winding Engines and Mine Shafts of Chatterley Whitfield Colliery — Chatterley Whitfield Friends

Record created: 22 August 2026 · Last researched: 22 August 2026