Patent GB-190702986-A (GB)
Title: Improvements relating to Electrical Apparatus for Transmitting and Receiving Signals.
Inventor: DAWSON ARTHUR TREVOR
Filed: 1907-02-06
Granted: 1908-05-06
Abstract: 2986. Dawson, A. T., and Buckham, G. T. Feb. 6. Order apparatus. -Two distinct sets of electric signalling-appliances are described of the type in which the signalling - devices of both transmitting and receiving instruments are operated by means o f synchronously acting step-by-step magnetic - field motors controlled by rotary hand switches at the transmitting s t ation, and particularly intended for use with the'range- ' keeper' described in Specification No. 9461, A.D. 1904. One set called the " spotting correction apparatus " (a) is used for signalling corrections in the range &c., from the observing-station to the station where the range-keeper is situated, while the other set, called the " rate-of-change apparatus," (b) is used for signalling the rate of change of the range. (a) The rotary switch B' of the spotting-correction apparatus, provided with the four insulated contact-rings b<1>, b<2>, b<3>, b<4>, is rotated by means of a handle B. The ring b<4> is divided into segments which are respectively electrically connected with the other rings. The current is supplied from the mains to the segmental ring b<4> by brushes, and is similarly collected from the other rings. A primary switch B', B<5> is actuated by a hand-grip B‹ on the handle B. The motors E, E, which are of the stepby-step magnetic-field type, rotate when the switch B' is rotated, and by means of worm-gearing d, d' and an electro-magnetic clutch cause the shaft d carrying the dial pointer to revolve. When the signal has been noted at the receiving-station, the operator there breaks the circuit momentarily ; the magnetic clutch in both instruments is then released and both pointers reassume the zero position under the influence of the fly-back arrangement shown in Fig. 6. When the pointer is at its zero position, the spring d<7> exerts an equal pull on both the toothed segments d<4>, d<5> ; but when the pointer moves in either direction, the whole pull of the spring is put on one of the segments, and when the magnetic clutch is released the pointer flies back to its original position. The receiver, Fig. 8, is very similar to the transmitter, and its motors E, E rotate in exact correspondence with the motors of the transmitter. The rotary switch is absent, and the contact-breaking press-button H is provided for the purpose already specified. For the purpose of giving audible indication when a message is being sent, a bell I is provided and is sounded by a hammer actuated by a cammed disk i on the motor shaft. (b) The rotary switch for the transmitter in the rate-of-change apparatus may be the same as has been described for the spotting - correction apparatus, but the contactrings of the switch B<6>, shown in Fig. 14, are arranged on a disk instead of on a cylinder. When the switch is rotated, the step-by-step motor rotates, and with it a drum carrying a series of rows of numbers printed on its circumference. This drum rotates behind a window. In order that only one number may be visible at a time, the drum is provided with a cylindrical shutter j in which a spiral row of apertures j<x> is cut. At the end of each complete revolution of the drum, two teeth on the gear-wheel j<4>, acting through a pinion on teeth in the sautter, cause the shutter to rotate one step and allow any one of a fresh row of numbers in the drum to be exposed. The rate-of-change receiver is similar to the transmitter, except that it is unprovided with a rotary transmitting-switch. Specifications Nos. 9461 and 29,422. A.D. 1904, [Abridgment Class Registering &c.], No. 4741, A.D. 1905, Nos. 8371, 8902, 17,844, and 29,665, A.D. 1906, and No. 2979, A.D. 1907, [Abridgment Class Registering &c.], are referred to.