A drawbridge is a movable bridge designed to secure a medieval castle by controlling access across the moat or ditch. It served as the first line of physical defense against attackers while allowing residents to pass during peace.

Core Mechanical Components:
The Bridge (Flap): A heavy wooden platform reinforced with iron bands to resist axe attacks and fire.

The Pivot (Axis): A massive iron-reinforced hinge at the castle gate base that allowed the bridge to swing upward.

Chains or Ropes: Heavy-duty iron links or thick ropes attached to the outer edge of the bridge to pull it up.

The Windlass: A hand-cranked winch mechanism located inside the gatehouse used to wind the chains.

Types of Drawbridges:
Chain-Lift Bridge: The simplest design using a winch and chains to lift the deck from the outside.

Turning Bridge (Counterweight): A highly efficient design where the inner third of the bridge drops into a pit inside the gatehouse as the outer two-thirds rise.

Turning Bridge (Gallows Style): Uses large overhead wooden beams (called gaffs) that look like a gallows to balance the weight and lift the bridge quickly.

Defensive Tactics and Integration:
The Gatehouse Pit: When a counterweight bridge was raised, it revealed a deep ditch underneath, creating a second trap for any enemy who breached the outer gate.

The Recess: Gatehouse walls featured a carved recess (rebate) so the raised bridge sat flush with the wall, leaving no leverage points for battering rams.

The Portcullis: Drawbridges always worked in tandem with a portcullis (a heavy iron-spiked grate) dropped immediately behind it for double security.