GB404447A - Improvements in apparatus for protection against burglaries - Google Patents

Abstract

404,447. Burglar alarms. SOC. ELECTRO-GARD, 7, Rue Sebastien-Gryphe, Lyons, France.-(Assignees of Yastrebow, P. ; 68, Rue Sebastien-Gryphe, Lyons, France.) Dec. 16, 1932, Nos. 35747 and 35748. Convention dates, Dec. 16, 1931 and May 26, 1932. [Class 118 (i).] Electromagnetically operated alarm apparatus of the type in which an electric contact is closed by the unauthorised opening of a door or other part, includes a one-way contact device with a rocking member which completes the circuit only when movement takes place in one direction. The arrangement of the apparatus on the inside of the door of a small cupboard is shown in Figs. 1 and 2 and the wiring diagram in Fig. 3. Electric current is supplied through terminals 1, 2 and is led through a control switch 4, located on the wall of the cupboard, to the fuses 3 from which it flows, when required, to (1) a circuit including the electromagnet 9 and (2) circuits through the alarm devices such as a bell 41, a maroon 42 and lamps 51. Unauthorised opening of a door etc. results in closure of one of the sets of contactors 30, 31, 301, 31<1>, thus completing the circuit through the electromagnet 9 which rocks the trip lever 11 and releases the rocking lever 7 so that it engages the contacts 18, 18<1>, 19, 20 supplying current to the alarm devices 41, 42, 57. The lever 7 is moved downwards by a spring 50 and is re-set by a lever 15 pivoted at 16, projecting outside the box, and having a pin-and-slot connection 48 at its inner end with the rocking lever 7. The current supply to the terminals 1, 2 may be taken from the main supply at a point between the meter 45 and the main switch 46. The rocking member 31, by which the alarm circuit is closed, is mounted on a plate 52 which is flush with the edge of the door &c. of the room to be protected, the member 31 projecting from the edge and being formed with projections A which engage the back of the plate 52 and enter a recess in the door. A spring 33 presses the rocking member outwards. When the door is opened, electric contact is made between the next projection A and the contactor 30, the member 31 rocking about the remote projection A and the alarm circuit being closed. When, however, the door is closed, the member 31 rocks about the near projection A, the remote projection then being moved into the recess in the door and the alarm circuit remaining open.