GB492161A - Improvements in automatic burglar and fire alarms - Google Patents

Abstract

492,161. Fire &c. alarm systems; gramophones. MOUNTSTEPHEN, E. R., WOOD, W. J., and SPENCE, A. G. Feb. 15, 1937, No. 4442. [Classes 40 (i) and 40 (ii)] [Also in Group XXXIX] In automatic alarm apparatus which transmits impulses for setting up a connection to a police &c. station and sends a gramophone message, different messages are sent in case of burglary and fire by means of two electromagnets, one energized on every occasion to set the apparatus in motion and the other, on certain occasions, e.g. fire outbreaks, to release mechanism for changing the initial position of the tone arm. The invention is described with reference to the apparatus described in Specification 484,308, the tone arm control mechanism being modified as shown in Figs. 2 and 3. The tone arm is carried by a spindle 19 mounted in an horizontally pivoted member 20 controlled as in the above mentioned Specification to lower and lift the tone arm. In the case of burglary the tone arm is lowered on to the commencement of the record and is returned thereto after the first half of the record has been transmitted, but in case of fire, an additional magnet 18 is operated to release a spring- controlled arm 29 to rotate a sleeve 28 carrying a plate 23 which by engagement with an arm 19a on the lower end of spindle 19 moves the tone arm to the commencement of the second half of the record whereupon lowering and lifting is effected as before. The Provisional Specification describes different mechanism including an inclined plane adapted to be interposed to cause the tone arm to slide to the second of its commencing positions. Specifications 442,565 and 484,307 also are referred to.