GB129289A - Improvements in or relating to Time Alarm Devices. - Google Patents

Abstract

129,289. Ford, H. C. July 3, 1918, [Convention date]. Time alarms.-A signal is given after an interval slightly less than the time of flight of a projectile from a gun, to warn the spotter or other observer that the moment of impact is at hand. A disk 15, rotated once a minute by clockwork, has a circle' of sixty pins 22, gripped frictionally by a coiled spring 24. When one of the pins 22 is pressed down, as shown in Fig. 5, it eventually tilts a lever 20, which releases the striking mechanism of a mechanical bell or closes an electric bell circuit. At the moment when the gun is fired, a rotatable arm 39, which has previously been set to an angular position corresponding to the range or the elevation of the gun, is depressed so as to push down one of the pins 22, which operates the bell after an interval corresponding to the preliminary setting of the arm 39. The depressed pin is restored to its normal position by a cam 27. The apparatus is mounted in a watertight casing, with external means for winding and starting or stopping the clockwork, for rotating and depressing the setting arm, and for silencing the alarm.