GB642440A - Improvements in or relating to electric alarm clocks - Google Patents

Abstract

642,440. Clocks. WEBER, M. Dec. 10, 1947, No. 32574. [Class 139] An electric alarm clock has an alarm contacting device comprising two concentric stationary insulated rings connected in the alarm circuit, a contact member which moves between said rings to form a connection therebetween and thereby close the alarm circuit, a slidable member carrying the contact member, the alarm hand, and a pin, displaceably mounted on the hour-hand spindle and urged by a spring against a notched ring carried on the hour-hand spindle whereby when the notch of the ring comes opposite the pin the slidable member can move axially in such a manner as to bring the contact member against the concentric rings and thereby complete the alarm circuit. The seconds, minutes and hours shafts 1, 3 and 5 respectively are co-axial, the seconds shaft 1 being driven by a synchronous motor. The reduction gearing between the shafts 1 and 3 comprises a planet wheel 14 rotatable on a spindle 13 carried by a bracket 12 mounted on the shaft 1 and meshing with two sun wheels 7 and 11 one of which 7 is carried by the minute shaft 3 and the other of which is carried by a sleeve 9 normally held against rotation by the action of a friction disc 22 and a spring disc 23. The hour shaft 5 is driven through similar gearing comprising planet wheel 16 rotatable on a spindle 15 carried by the minute sun wheel 7 and two sun wheels 8 and 10. The sun wheels 10, 11 may be rotated for handsetting. Alarm mechanism. A fixed insulating plate 24 carries two concentric contact rings 26, 28 connected by conductors to screw terminals 30, 31 which are in circuit with an electric alarm device. A wedge contact 43 carried by a settable wheel 41 axially movable on the hour shaft 5 moves between the rings 26, 28 to effect closure of the alarm circuit when a pin 40 carried by the wheel 41 coincides with a notch 37 in a disc 35 fixed to the hour shaft 5.