Patent GB-190017663-A (GB)
Title: Improvements in Method of and Apparatus for Signaling between Stations having no Electrical or Mechanical Connection.
Inventor: SILKMAN EDWARD JENNINGS
Filed: 1900-10-05
Granted: 1900-12-01
Abstract: 17,663. Silkman, E. J., Selden, C., and Day, E. W. Oct. 5. Telegraphs, mechanical.-Relates to apparatus for signalling between two unconnected stations, such as two ships or two parts of an army. Discs marked with letters &c. are rotated at the same speed at the sending and the receiving station. When the letter to be telegraphed reaches a pointer in front of the sender's disc a signal is made by means of an electric lamp, a semaphore or other signalling-device. The receiver then reads off the letter which is under the pointer on his disc. Fig. 4 shows the apparatus arranged in conjunction with an electric lamp N, having a shutter M<1> which can be withdrawn by energizing the magnet M. The sender closes the switches L' and L', and starts the motor which rotates the disc G. When the letter to be sent is beneath the pointer H he presses the key L uncovering the light. The receiver has his switches L and L<2> closed, and on observing the flash closes the switch L'. This sends a flash signal in acknowledgment, and at the same time gives a movement to the pointer H by means of the current sent through the magnet H<3>. It is convenient to employ two operators at the receiving-station who need not be close together. For instance, the operator who observes the flashes or other signals and manipulates the switch L<1> may be on the deck of a ship, while the apparatus and the reader of the signals may be in a cabin. Special mechanism is employed to synchronize the discs G bearing the letters &c. to be telegraphed. The discs are driven by clockwork motors, which move them at the same approximate speed, so that it is only necessary to provide means for their adjustment when commencing to send a message. Fig. 6 shows the mechanism employed. The chain O drives the sprocket-wheel D<1> on the sleeve D, which is geared to the sleeve F carrying the disc G through the bevel wheels D<2>, E', F'. The intermediate wheel E<2> is mounted on the shaft C, and is balanced by the counterweight E<3>. If the shaft is fixed, the disc G is moved uniformly at the same rate as the sprocket-wheel D<1>. At starting, a predetermined letter is signalled by the sender a certain number of times, by sending the flash signal each time the said letter is under his pointer. The receiver, while this is being done, releases the shaft C, and turns it by means of the milled head R so as to bring the predetermined letter under his pointer H each time he receives the signal. This turning of the shaft C in no way interferes with the uniform rotation of the disc G, but simply gives it the additional movement necessary to adjust it. If it is desired to give the disc G a step by-step movement, the escapement shown in Figs. 6, 7, and 8 is employed. The cam d<3> on the sleeve D acts on the arm T, which is connected with the arm T' provided with pawls t<2> engaging the ratchet-wheel U on the sleeve F. In this form of the apparatus, the shaft C is not fixed, but is fitted with a friction device, so that it moves while the disc G is stationary, and remains stationary while the disc G is moving. An audible signal, such as the sound of a pistol, may be used for signalling instead of a flash or other visible signal, provided the distance between the sender and receiver is approximately constant.