Electromechanical trigger for alarm clocks and other timer- operated signal emitters

摘要

An alarm clock has a cambered leaf spring traversed by a nest of clock- hand shafts projecting from a mounting plate designed as a printed- circuit board. The leaf spring is supported at opposite ends by posts rising from the mounting plate and is limitedly swingable about a centerline parallel to that plate and perpendicular to the axis of the nested shafts. A toothed control disk centered on the same axis, with a hub carrying an alarm hand, is axially shiftable under pressure of the cambered leaf spring upon alignment of a tooth on that disk with a notch in an adjoining hour wheel; two diametrically opposite metallic contacts formed by lateral tongues on that spring then engage respective countercontacts on the mounting plate to close a circuit for the emission of an acoustic alarm signal. The alarm circuit can be broken by a manually displaceable interrupter lifting one of these tongues off its countercontact; with a modified alarm circuit, closure of one or the other contact pair can be selectively inhibited to enable the alternative operation of a buzzer or of a radio receiver upon displacement of the control disk by the leaf spring.