This specialized safety device connects the winding rope to the conveyance in a vertical shaft. If the hoist operator fails to stop the cage at the surface landing, the device is drawn into a catch plate. The mechanism then shears a copper pin, releases the hoisting rope, and locks the cage safely in place to prevent a catastrophic fall or collision.
Maintenance needs to inspect the butterfly and replace the shear pin before we resume manwinding operations on the main shaft.
Related terms
Cage
The primary elevator car used in vertical mine shafts.
Headframe
The structural frame above an underground mine shaft that supports the hoisting mechanism.
Winder
A heavy-duty winch or engine used to raise and lower cages and skips in a mine shaft.
Manwinding
The specific operation of raising or lowering personnel through a mine shaft using a hoist and cage.