Patent GB-127837-A (GB)
Title: Improvements in or relating to Electrical Apparatus for Transmitting and Indicating Orders, Numerical Data and the like.
Inventor: GRAHAM EDWARD ALFRED
IPC: G09F9/00
Filed: 1917-01-11
Abstract: 127,837. Graham, E. A. Jan. 11, 1917. Order apparatus. -The transmitter and receiver of an electric signalling system for orders and numerical data are mounted on supports which serve electrically to connect the step-by-step motors of these devices to the controlling-circuits. The transmitter may be provided with an illuminated translucent screen upon which the orders are printed, and along which travels a pointer mechanically connected to the operating-arm; and an electrically-operated indicator carrying the same series of orders is arranged to move synchronously with the pointer, so that the displayed order and the order opposite the pointer are in agreement. When a " repeat back " is required, the electrically-operated indicator is controlled from the receiving-station. The step-by-step motors of the transmitter and the receiver may be of the kind described in Specification 125,454, and are controlled by a rotary switch comprising four fixed contact fingers, one of which is connected to the positive pole of the source of power and the others to the leads between the transmitter and the receiver, and an insulated rotary contact member adapted to engage successively the contact fingers connected to the leads. Indicating-units a, c, Fig. 2, and an indicating-unit b are mounted in a casing d the cover e of which is provided with glazed apertures f and a glazed aperture f<1>, Fig. 1. The indicating-unit b comprises a number of orders A - - J on a translucent screen e<1> along which a pointer z travels, and a glazed aperture f<1> opposite which the orders A - - J are successively moved as the pointer z travels from A to J. The indicators at the transmitters act as tell-tale devices, and their motors are connected in parallel with the corresponding motors of the receivers and are controlled by the same switches. Each of the rotary transmitting-switches g, h, i, Fig. 5, comprises a flanged vulcanite cylinder p, Figs. 6 and 7, to which is secured a pinion k and a metal disk s the peripheral portion s<1> of which partly surrounds a glass ring r mounted on the cylinder p. A spring contact finger t, Fig. 5, bears against the disk s and three spring contact fingers 1, 2, 3 are arranged to engage the portion s<1> of the disk s as this rotates. When a motor of the kind described in Specification 125,454 is employed, the portion s' is made long enough to engage at one time, and in certain positions, two of the contacts 1, 2, 3. The pinion k is engaged by a pinion m connected to an operating-handle o, Fig. 1, and, in the case of the indicator b, this pinion also engages a rack u carrying a pointer z, Figs. 1 and 5. As the switch h of the transmitter b is operated to transmit electric impulses to the operating-motors of the indicator of the transmitter b and the corresponding distant receiver. the pointer z travels along the screen e<1>, which does not extend beyond the line y<1>-y<1>, and is seen through a glass screen 6, which is protected by a grid 7, Fig. 2. The screen e<1> is illuminated by lamps 28. The contacts t. 1, 2, 3, Figs. 4 and 5, are mounted on metal posts u - - x which are connected respectively to fixed terminals 13 - - 16 by metal strips 8 - - 11 fixed to the insulating- base 12 of the casing d. The terminal 13 is connected to the positive pole of the source of energy, and the terminals 14, 15, 16 are connected by separate leads to corresponding terminals of the distant indicating-device; while a terminal 17 is connected to the negative pole of the source through a strip 18<a> and to the return conductor of the distant receiver. Each indicator, together with its operating-motor, is removably supported in the casing d on four conducting-pillars 18 - - 21, Figs. 2 and 4, mounted on the strips 9, 10, 11, 18<a> respectively. The conducting-pillars 18 - - 21 are engaged by four metallic tubes 14<b> - - 17b forming the terminals of the motor, and secured to the indicating-unit by insulated metal lugs. The ends of the pillars are screwed to receive retaining cap-nuts 26 which are locked by compressed spiral springs enclosed in the enlarged parts 26<a> of the nuts 26. The leads, in the form of a cable, pass into the casing d through a water-tight gland 27 as described in Specification 16155/15, [Class 36, Electricity, Conducting &c.].