Electric Bell Provides Steady Alarm to Rouse Sound Sleepers (Feb, 1947)
Looks like a bomb from a bad T.V. show.
Electric Bell Provides Steady Alarm to Rouse Sound Sleepers
If your wind-up alarm clock runs through its short tinkle without disturbing your slumber, try using this electric bell that will keep on ringing until you disconnect it. It employs a doorbell transformer and bell, housed in any decorative box that blends with the bedroom furniture.
Drill the alarm-wind key for a string tied to a small rod. A spring mounted along one edge of the box acts as the moving contact, while the other connection is carried to a screw head placed beneath the free end of the spring. Bend the last turn of spring wire flat and fill it with solder. When the clock goes off, the unwinding key pulls the rod from under the spring and starts the bell jangling. The contacts can be placed on a ledge inside the box if you’d rather not notch the edge.