| 摘要 |
PURPOSE:To improve reliability in time detection by forming circumferentially plural contact points on a base plate, connecting the contact points except one point to each other by means of resistors, providing a contact piece which rotates to contact slidingly with each contact point and measuring the resistance between the connecting ends on the circumference and the contact piece. CONSTITUTION:Twelve contact points 2 are formed in the 1-12 o'clock positions on the same circumference of a base plate 1. The contact points 2 are connected to each other by means of resistors 3. The parts between 1 o'clock and 12 o'clock are not connected. A contact piece 5 is fixed to a clock pipe 4 penetrating through the center of the circumference of the plate 1. The piece 5 contacts with the point 2 at every one hour. The contact points in the 12 o'clock and 1 o'clock positions are connected respectively to the + side and - side of a power source. The voltage outputted from the piece 5 increases successively with the display of the hour hand and therefore a time-announcing sound is generated at every one hour by detecting said voltage. |
