The Contact Springs are Operated by the Pins on the Disk Wheel (Fig. 4)
The parts are connected up electrically as shown in Fig. 5. The lines between the clock, Fig. 1, and the bell-ringing part, Fig. 2, are connected from C to C, D to D, and E, Fig. 1, to the zinc of a battery and from the carbon to E, Fig. 2. Two dry cells will be sufficient for the current.
The Wiring Diagram for the Location of the Wires on the Under Side of the Base (Fig. 5)
The working of the mechanism is as follows: Suppose the time is 6 minutes of 3 o'clock and the contact spring on the back is near the 11 pin. As soon as it touches the pin, the armature K of the switch will be drawn in contact with the spring N, then when the contact spring touches the 12 pin, the current will flow into the magnets T and release the wheels of the clockwork F, which turns the disk Q, and the three pins in the second row will pass over the spring 5 and press it in contact with the spring 4 three times, causing the gong X to toll out 3 o'clock. As the contact spring B will be on the contact pin 12 for about 1 minute, the wheels of the clockwork F would continue to turn and the bells ring, if it were not for the stop pin located on the outside, or first, circle of the disk Q, which pin is set in line with the last pin in the set of pins for the hour, or, in this instance, in line with the third pin. When the stop pin has passed the spring, the connection through the magnets T is broken and the clockwork F stops instantly. When the spring B strikes the 2 o'clock pin, or 10 minutes after 3 o'clock, the armature K is drawn over to N, and at the 3 pin, or 15 minutes after 3 o'clock, the bells U, V, and W will ring and then the stop pin will break the current, and so on, at every 15 minutes of the 12 hours.
Hinges Used to Substitute Night Bolt
One of the safest devices for bolting, or locking, a door against intruders is to use two sets of hinges. The extra set is fastened to the door and frame in the same way but directly opposite the regular hinges. It may be necessary to file the extra hinges and pins in order to separate and bring the parts together easily. The usual door lock need not be used with this arrangement, as the hinges are exposed only on the inside of the room and cannot be tampered with from without.
Propellers for a Hand Sled
Desiring to propel my hand sled with power transmitted by cranks and wheels, I set about to procure the necessary materials. Two medium-sized buggy wheels were found in the back yard of a blacksmith shop, which were procured for a nominal price. The fellies of these wheels were removed, the tenons cut from the spokes and nails substituted, which were driven in their ends so that about 1/2 in. of the body with the head projected. The heads were then removed and the nail ends sharpened.
The hubs were plugged with pieces of wood, whittled to tightly fit the holes. A hole was then bored exactly central through each plug for a 1/2-in. rod. This size rod was procured and bent to form a crank, the bearing end being threaded for a distance equal to the length of the hub.