Casement bolt locking device - has linkages held retracted and spring loaded outwards to engage on shutting

摘要

The casement bolt linkage locking device is particularly for the fixed or supporting section of two-section firestop doors, having a single or double acting emergency function. Two sets of linkages move in opposite directions under the action of a single handle, the outer ends fitting, when the door is shut, automatically in recesses in the stationary portion at top and bottom. The linkages are spring-loaded towards the extended position, and work in conjunction with a device holding them in the retracted position when the door is open, but releasing them on shutting. Typically, the device can be released by an auxiliary catch on striking a plate on the top part of the door frame.