Time detecting device for alarm clock

摘要

The cam type time detecting mechanism of an alarm clock has a time gear wheel, an alarm gear wheel and a detecting plate, all mounted on a shaft. A hole is formed on either the alarm gear wheel or the detecting plate and a projection is formed on the other. The detecting plate is movable on the shaft in the axial direction of the shaft. The time gear wheel and the detecting plate have guiding parts respectively so that the time gear wheel, in its normal rotation, continuously pushes and turns the detecting plate. At least one of the time gear wheel, the alarm gear wheel and the detecting plate has a cam for lifting up the detecting plate if the time gear wheel and the alarm gear wheel turn either in normal and reverse directions.