Fig. 145. Chimes of bells with resonators.
[Fig. 144] shows a peal of bells in which the rack is thirty-six inches long and the height of the largest bell is eight inches, and the total weight thirty pounds. This, as will readily be seen, can be placed above a doorway or any other convenient position for operation; or it may be enclosed in a lattice on the roof, if the building is not over two stories in height. The lattice work will protect the bells from the weather and at the same time let out the sound.
[Fig. 145] shows the same apparatus with resonators attached. These are hollow tubes which serve as sounding boards, largely increasing the sound and giving the effect of much larger bells. [Fig. 146] shows a tubular chime and the electrical connections from the clock to the controller and to the hammers, which are operated by electromagnets, so that a heavy leaden hammer strikes a solid blow at the tops of the tubes.
Fig. 146. Tubular electric chimes.
The dials of such clocks contain electrical connections and the minute hand carries a brush at its outer end. The contact is shown in enlarged view in [Fig. 147], by which it will be seen that the metal is insulated from the dial by means of hard rubber or other insulating material, so that the brush on the minute hand will drop suddenly and firmly from the insulator to the metallic contact when the minute hand reaches fifteen, thirty, forty-five or sixty minutes. There is a common return wire, either screwed to the frame of the clock, or attached to the dial, which serves to close the various circuits and to give four strokes of the chimes at the quarter, eight at the half, twelve at the three-quarter, and sixteen at the hour, followed by the hour strike. The friction on the center arbor is of course adjusted so as to carry the minute hand without slipping at the contacts.
Fig. 147. Enlarged view of connections on dial.