Locking mechanism with overload protection for passage barrier

摘要

The horizontal crossbeam (5) is mounted on a vertical tube (1) turning round an inner one (2). The bolt (6) engages in recesses (3,4) of different depths in the tube, and is actuated by large (7), small (11) and torsion (15) springs, acting via a thrust washer (9), a locking cylinder (10) and a cam (14). A key is required only to open the barrier, turning the cam from the locking position so that the mechanism can be opened in opposition to the small spring. In the open position the bolt engages in the shallower recess, holding the barrier in this position, when the cam does not reach the locking position. Thus the barrier can be shut again without using the key, in opposition to the small spring. On reaching the shut position, the bolt engages in the deeper recess under the action of the small spring. The cam then comes free of the cylinder and is moved by the torsion spring into the locked position automatically.