GB559551A - Improvements in time alarm devices - Google Patents

Abstract

559,551. Time alarm signals. WOOD, S. Aug. 20, 1942, No. 11733. [Class 118 (ii)] [Also in Group XXXVII] A time alarm device comprises stationary contacts connected in the circuit of an electric bell or other suitable warning-device, and a movable contact mounted on a screw-threaded spindle that revolves at a regulated rate. The movable contact is traversed along the spindle and makes contact with the stationary members to close the circuit after a predetermined time. The screwed shaft c, Fig. 2, is provided with a socket c<SP>1</SP>, which clips on to the rear end a' of the spindle a of the minute hand of a clock in place of the knob which is used for adjusting the hands. The stationary contacts consist of two resilient members g<SP>1</SP>, g<SP>2</SP> carried by a strip of insulating material j which is attached to the back of the clock b by brackets k. The movable contact consists of a disc d of insulating material which screws on to the shaft c and is provided with a metal ring e. The shaft c is rotated once an hour by the clock spindle a, and the disc d travels along the shaft because it is prevented from rotating, by a pivoted rod p that rests in a notch f in the disc. Eventually, the movement of the disc causes the ring e to bridge the controls g<SP>1</SP>, g<SP>2</SP> and complete the circuit of the warning device. In use, the disc f is caused to complete the circuit and is then revolved in the opposite direction a number of turns requisite to complete the circuit after a desired interval. In a modification, the rod p is dispensed with, a weight being provided to prevent the disc c from rotating. In another modification, the spindle c may be connected to the clock spindle by a driving chain or belt so that the device may be mounted alongside the clock. The device may be used as a time-operated means for closing any suitable electric circuit.