Patent GB-191022602-A (GB)
Title: Improvements in and relating to Safes.
Inventor: BRIDGER THEO EUSTACE
IPC: E05G1/10
Filed: 1910-09-29
Granted: 1911-11-29
Abstract: 22,602. Bridger, T. E. Sept. 29. Burglar alarms.-An alarm apparatus for use with safes, gas-meters, coin-freed machines, doors, and windows comprises an exhausted or pressure - containing casing a, Fig. 2, within which is an air-pump g<4> automatically operated to maintain the desired pressure, when the door is closed. The pump is driven by an electromotor g<3>, supplied by current from a suitable source, and having in the circuit thereof a Bourdon gauge a<18> and a contact g<6> on the door. The alarm arrangement a<17>, Fig. 3, is supplied with current from a battery a<12> outside the casing, and is operated, when its circuit is completed, by the movement of a contact-maker a<16> under the control of electro-magnets a<15> when there is variation in the current which traverses wires k<6> extending to the chamber a. A number of external resistances a<13> and an internal resistance a<14> are in the circuit k<6>, rendering it impossible for an intruder to shortcircuit the wires k<6> by a resistance equal to the resistances a<13>, a<14>. The circuit k<6> is controlled by a contact-maker k<2>, Fig. 2, operated by an electro-magnet k<1> energized by a battery k and having in its circuit a gauge k<5> adapted to close the circuit on alteration of the pressure in the casing a, and by a code-set contact arrangement b<3> which closes the circuit on opening the door a<10>. The contact device b<3> comprises a fork-shaped part b<4>, Fig. 9, adapted to receive a member c<8> rotatably mounted on the part b<5> and having brushes d<2>, d<3> connected to leads c', c<Î>. The part b<5> comprises a number of disks b<6>, Fig. 11, carrying the letters &c. of a code and having sleeve-like extensions c carrying conducting contact-disks c<3> having insertions c' of insulating - material. The member c' is mounted adjacent to the disk c<3>, and carries a conducting strip d adapted to make contact with the disk c<3>. The brushes d<2>, d' engage contact-pieces d, b<7> on the part c<8>. The strip b<7> has an opening b<8>, Fig. 10, which receives the brush d<2>, when the door is closed and breaks circuit. The brush d<3> bears on the strip d, and, if the door is opened without setting the disks, the members c<3> bridge extensions b<7Î>, d<Î> of the pieces b', d and complete the circuit. In order to avoid operating the alarm by inadvertently closing the door, the part b<5> carries a spring lever f<3> having teeth f<4> and a tail-piece f<5>. When the door is closed, the tail-piece engages the wall of the casing a and retains the extension f<4> out of engagement with the disks c<3>, but, if the door is opened, the disks being set, the lever f<3> is released and the teeth f<4> engage depressions f<6> in the disks c<3>. When the disks b<6> are subsequently turned to upset the combination, the member c, which is elongated in section, is also rotated so that it does not enter the slot of the part b<4> and prevent the closing of the door. In a modification, a motor k', Fig. 5, operates a pump k<8>, the current for the motor being supplied through leads k<18> and controlled by a switch k<13> operated by magnets k<9>, k<10>, which are controlled by a gauge k<14> in the circuit of a battery k<17>. A gauge h within the casing is in the circuit of the alarm device, which is connected to the casing by leads h<Î>, h<4> within a double tube h<2>, h<3>. If the casing is punctured, the motor will be started but is unable to cope with the inrush of air, and the gauge h then makes contact. An additional gauge may be provided to operate an alarm to indicate slight leakage. A brush contact in circuit with a bell may be so arranged as to test the battery each time the door is opened or closed. An indicating-device may be employed comprising a spring or gravity controlled striker retained by a trip b<11>, Fig. 8, which is liberated by a lever b<12> operated when an electro-magnet b<13> is energized. The striker fires cartridges b<14> by means of a detonator. The alarm may be operated by wireless means, a suitable transmitter and receiver being provided.