FM 89: assessment of formal methods for trustworthy computer systems

An alarm setting device for a timepiece that can be operated by means of an axle for adjusting the alarm setting wheel, by rotating it in a clockwise and a counterclockwise directions. The device includes an alarm setting wheel, an alarm intermediate wheel, and an alarm setting cam, all disposed coaxially. The alarm setting wheel is rotated and adjusted by the alarm setting wheel adjusting axle. The alarm intermediate wheel rotates together with a wheel train of a timepiece. The alarm setting cam is provided between said alarm setting wheel and alarm intermediate wheel. A protrusion provided in the alarm setting cam engages with a loose joint provided in the alarm intermediate wheel. Through this engagement, the alarm intermediate wheel drives the alarm setting cam by dragging it loosely. On the respectively facing surfaces of the alarm setting cam and the alarm setting wheel, either an alarm finger or an engaging portion is provided, respectively. Either the alarm finger or the engaging portion has a sloped depression surface and a sloped shoulder, thereby making it possible to perform alarm setting in reciprocal directions.