15,600. Case, E. N. July 16. Locks, key.-An alarm lock for trunks, chests, boxes, sliding doors, &c. is adapted to explode a cartridge or sound a similar alarm when the lock is tampered with. The lock is shown as applied to a trunk, a hasp portion B, Fig. 1, shown turned down, being pivoted to a bracket E on the body, and carrying the lock mechanism in a case C. Fig. 2 shows a rear view of the case C with the cover-plate D removed. A key-actuated cylinder 4, Figs. 2 and 8, with a slot 13 to receive the keybit, has a disc 3 with a stump 8, which traverses slots 20 in spring levers r, when these are operated by the proper key. The rotation of the cylinder brings a T-piece 10, Fig. 1, on its inner end into alignment with a slot 15 in the striking- plate A, and allows the hasp to be turned down as shown. The operation of the lock by the proper key has no effect on the firing-mechanism. The cylinder must be turned to the locking position before the key can be removed. A pin 6 on the disc 3 engages the hammer boss i to limit the rotation of the cylinder. The firing- hammer a is pivoted at i, and is operated by a spring d, the cartridge &c. being placed in a barrel l and held by a pivoted plate or breech-block p. The hammer is set by a finger-piece n and held by a pin o on a crank lever t engaging a lug e on the hammer boss. A pin u on the crank lever passes through slots in the spring levers r, arranged to allow the latter to move correctly without touching the pin. Should one lever be moved too far by a false key, the crank lever is disengaged from the lug e and the hammer falls, the firing-pin m striking the cartridge and sounding an alarm without releasing the lock mechanism. To give an alarm when the trunk &c. is being forced, the case C and hasp B are connected by a yielding connection such as the rod I and spring F. A second rod w on the hasp passes into the case C and has a pin v engaging the tail of the crank lever. On force being applied to open the lid, the resulting relative movement between hasp and case operates the crank lever and releases the firing-mechanism. The alarm mechanism may be applied to any suitable lock mechanism.