The accompanying photographs show a vibrating-fork-control employed to
keep distantly separated motors in synchronism. This is the motor
control employed in the system developed by the author for the sending
and receiving of photographs and photograms, by radio and by wire.
The control unit is surprisingly simple and dependable, and is believed
might be found useful for many other purposes where it is desired to
keep motors in step with each other which are separated by long
distances, the control signals being sent by wire or by radio, and from
fixed or moveable stations, on land, on water, or in the air.
The fork illustrated is about fifteen inches long, mounted on a cast
brass frame with a bakelite cover plate upon which the fork, motor coil,
and binding posts are mounted. A single cell of dry battery keeps the
fork in vibration.
The device is designed on a new principle, and has a very sharp control
of the motor revolutions. Simple means are provided for easily verifying
the continuity of the motor control.
These fork motor units will control any number of motors of any size, at
any distance, and on moveable or stationary platforms.
[Illustration: [Photographs]]