Crawford chain hoist, Ratio 1-5, for hexagonal shaft.

This component is a manual chain‑drive mechanism that mounts directly onto the hexagonal torsion shaft of a Crawford sectional overhead door. It allows the door to be opened and closed by hand using a pull‑chain whenever the electric operator is unavailable or when the door is designed for manual operation only.

The 1:5 ratio means the hoist provides a five‑times mechanical advantage: