Patent GB-119099-A (GB)
Title: An Improved Electrical System for Indicating an Alarm of Fire or such like Simultaneously at Any Required Number of Points or Stations.
Inventor: BROWN ALEXANDER WALKER
IPC: G08B17/06
Filed: 1917-09-26
Abstract: 119,099. Brown, A. W. Sept. 26, 1917. Fire, police, and like alarm systems and apparatus - In a single-line fire or like alarm system of the kind described in Specification 24183/10, in which each station is provided with a location visual receiver, a bell and a code impulse transmitter, the impulse transmitter consists of a mercury switch operated by the code wheel; while each location receiver is provided with a test indication to which the receivers are moved by an impulse sent from the fire station. The transmitter and receiver are mounted in the same casing, and the line circuit is broken when the casing is opened. Transmitter. The transmitter consists of a disk j, Fig. 1, provided with a retaining notch j<3> and pins f<2>, a pendulum or balance-wheel escapement j<2>, a weight d<1> which rotates the disk j, a controlling magnet e<1>, the armature g<1> of which normally engages the notch j<3> and a mercury switch kl, l operated by an arm k the counterweight k<2> of which is adapted to be operated by some of the pins f<2> which are longer than normal. Receiver. The receiver, Figs. 1 and 5, consists of an indicator disk a mounted on a pulley f<1> adapted to be rotated by a weight d and provided with stop-pins f, a controlling electro-magnet e the armature g of which engages the stop-pins f, and a two-position switch h controlling the circuit of the transmitter magnet e<1> and a bell K, Fig. 2. The switch h is controlled by a projection i on the pulley f<1>. The disk a makes a complete step in two movements by providing the armature g with two fingers g<2>, g<3>. Normally a pin f engages the finger g<3> but upon the attraction of the armature g, the finger g<3> is disengaged from its pin and the finger g<2> is moved into the path of the next pin from which it is disengaged to engage the finger g<2> when the armature is retracted. Operation. To give an alarm, the switch N, Fig. 2, at a station is manually or thermally operated to close the following circuit; terminal b<1> of battery No. 2, lead G, terminal b<2>, Figs. 1 and 2, lead G<3>, contact h<1> nf switch h, lead H, terminal R, magnet e<1>, lead S<1>, terminal S, lead S<2>, switch N to earth. The disk j is thereby released and operated and controlled by the weight d<1> and escapement j<2>. As the long pins f<2> come under the weight k<2> the lever k is operated to close the switch k<1>, l to send impulses to line F as follows :-Terminal I of battery No. 1, lead L, terminal I<1>, Figs. 1 and 2, lead L<1>, magnet e, lead M, terminal O, lead F'. The impulses received by the magnets e at the distant stations allow the disks a to be rotated in a step-by-step manner; and when the projection i of each receiver disengages from the switch lever h the lever operates to close circuit of the bell K or a relay controlling a steam-horn. Testing. To test the system, the transmitter at the fire station is provided with a single pin f<2> of sufficient length to operate the switch k<1>, l and the first position of each disk a is marked " Test."