Portable intrusion alarm

A portable alarm device for closures comprising a mounting plate, an alarm switch, an on-off switch and an audible electrical alarm element secured to one side of the mounting plate, a battery holder on the same side of the mounting plate and having a pair of spaced ears formed integrally thereon, the mounting plate having spaced slots receiving said ears and the ears projecting beyond the other side of the mounting plate, said battery holder having a substantially U-shaped body portion including a flat base lying against the mounting plate and being fixed thereto, said spaced ears being directly attached to said flat face at opposite sides thereof and extending substantially at right angles to the flat face and said mounting plate, said alarm switch having an actuating plunger projecting beyond said other face of the mounting plate, a hanger bracket for said alarm device having a plate body extending near said mounting plate, said plate body having a pair of spaced ears formed integrally therewith and interfitting laterally with the ears of the battery holder, a pintle hingedly connecting the ears of the battery holder with the ears of the plate body, a coiled torsion spring surrounding the pintle between said ears of the battery holder and having ends bearing on the mounting plate and said plate body and biasing the mounting plate pivotally in one direction relative to said hanger bracket, and said hanger bracket including a substantially right angular extension which is transversely corrugated and said extension carried by the upper end of said plate body, and a coacting L-shaped corrugated hanger extension on the hanger bracket whose corrugations interfit adjustably with the corrugations of said extension, whereby the effective width of the hanger bracket may be varied to accommodate closures of different thicknesses, and separable threaded fastener means securing the interfitting corrugations in selected adjusted positions.