Key lock with a flying sidebar

This invention describes a pickproof key lock where the key sets up a series of tumblers each of which has a notch or other configuration that cooperates with a sidebar. This sidebar, when out of engagement with the tumblers, keeps the lock in the inoperative position. The sidebar does not contact the tumblers and is kept in this position normally by the action of two opposing preloaded springs. When a key is inserted into the lock, the internal mechanism is made to operate on the sidebar to move it further away from the tumblers. The mechanism then releases the sidebar and the sidebar is propelled towards the tumblers by the action of a spring. If the tumblers have been properly set, as by a correct key, the sidebar enters the notches in the tumblers and is latched in that position. The lock can then be opened. If any of the tumblers were not set correctly, the sidebar simply impacts against such tumblers and is returned to its normal rest position out of contact with the tumblers. There are no openings for tools or other external means by which the sidebar can be made to press against the tumblers in order to pick the lock. The external mechanism can only move the sidebar away from the locked position and only the inertia of the sidebar after it is triggered enables it either to contact incorrectly set tumblers for a brief instance or to enter all of the tumblers, when correctly set, and be latched in this position.