Transmission mechanism

A transmission of a locking arrangement comprises first 22 and second 24 elongate drive bars connected together by a coupling arrangement 26. The coupling arrangement is captive on the first drive bar and movable, e.g. sliding, toward the second bar having a locking member to secure it in place. The coupling may comprise of a first clamp (34, fig.4) with a threaded aperture and a second clamp 40 sliding in channel in the first drive bar; the clamps are secured by the lock/screw 28 to clamp between them the second drive bar which has a slot 72 forming a bifurcate end. The second drive bar may include a retractable locking bolt 20. The length of the drive bars can be adjusted by cutting the first drive bar to length to suit different sizes of door or window.