drawbridge

A drawbridge is a simple type of openable bridge whose span rises on a hinge when the free end is lifted by chains, cables, or ropes. The opening motion is similar to a bascule bridge, but it operates without counterweights on the hinge.

The lifting connection acts at the free end while the other end turns about a hinge. Chains, cables, and ropes are alternative means of supplying that lift.

The absence of a counterweight at the hinge distinguishes this drawbridge form from the separately defined bascule bridge. The term does not encompass every bridge capable of opening.