(under subclass 38) Devices wherein the penetration of the wall by attack initiates the operation.
(1) Note. The word "wall" is to be interpreted broadly to include a screen, a grille, or any other confining mechanism.
SEE OR SEARCH THIS CLASS, SUBCLASS:
31, for the puncture of a wall to release a fluent material under pressure, or to allow the influx of air to bring up the
pressure to that of the atmosphere.
38, for operation initiated by an attack upon the wall that does not penetrate the wall.
SEE OR SEARCH CLASS 340, Communications: Electrical,
544, for fluid flow operated alarms such as those in which the fluid is released when a hollow bar is sawed by a trespasser, and subclass 550 for electrically actuated alarms which are automatically responsive to the penetration of screens, walls, roofs, floors, etc.
