This section is from "Scientific American Supplement Volumes 275, 286, 288, 299, 303, 312, 315, 324, 344 and 358". Also available from Amazon: Scientific American Reference Book.
The Brunot Controller, which has been employed for several years on the Railway of the North, is designed to control the regularity of the running of trains, and to make automatically a contradictory verification of the figures on the slips carried by the conductors. In Fig. 11 we give a longitudinal section of the apparatus. It consists of a wooden case containing a clockwork movement, H, upon the axle of which is mounted a cardboard disk, C, divided into hours and minutes, and regulated like a watch, that is to say, making one complete revolution in twelve hours. The metallic pencil, c, which is capable of displacing itself on the cardboard in a horizontal direction opposite a groove on the other side of the disk, traces, when pressure is brought to bear on it, a spiral curve. The transverse travel of the pencil is effected in ninety-six hours. The displacement of the pencil is brought about by means of a cam. Under the influence of the jarring of the train in motion, a weight, P, suspended from a flexible strip, l, strikes against the pencil, c, which traces a series of points. During stoppages there is, of course, an interruption in the tracing of the curve.
Up to this point no electricity is involved - the apparatus is simply a controller of regularity. Mr. Brunot has conceived the idea of utilizing his apparatus for controlling the passage of trains at certain determined points on the line; for example, at the top of heavy grades. For this purpose it has only been necessary to add to the apparatus that we have just described an electro-magnet, E, connected electrically with a fixed contact located on the line. When the current passes, that is to say, at the moment the circuit is closed by the passage of a train, the armature, A, is attracted, and the pencil marks a point on the cardboard disk. This modification of the apparatus has not as yet been practically applied.
The object of these apparatus is to quickly transmit to a distance a certain number of phrases that have been prepared in advance. The Company of the North employs two kinds of correspondence apparatus - the Guggemos and the annunciator apparatus.
1. The Guggemos Apparatus. - This apparatus serves at once as a manipulator and receiver, and consists of an inner movement surmounted by a dial, over the face of which moves an index hand. Around the circumference of the dial there is arranged a series of circular cases, C, containing the messages to be received, and similar triangular cases, containing the messages to be forwarded, radiating from the center of the dial. Between each of these there is a button, b.
Fig. 13 represents the interior of an apparatus for twenty messages. It consists of a key-board, M, an electro-magnet, B, a clock-work movement, Q, an escapement, s, and an interrupter, F G.
When one of the buttons, b, is pressed, one of the levers of the key-board arrangement touches the disk, M, which is insulated from the other portions of the key-board, and the current then passes from the terminal C to M, and there bifurcating, one portion of it goes to the bobbins of the apparatus and thence to the earth, while the other goes to actuate the correspondence apparatus. The index-hands of the two apparatus thereupon begin their movement simultaneously, and only stop when the pressure is removed from the button and the current is consequently interrupted. H is a ratchet-wheel, which, like the key-board, is insulated from the rest of the apparatus. The button, K, located over each of the dials, serves to bring the index-needles back to their position under the cross shown in Fig. 12. The key, X, serves for winding up the clock-work movement.