Patent GB-209133-A (GB)
Title: Improvements in electrical switch boards and circuit selecting apparatus
IPC: H02B1/00
Filed: 1922-09-01
Abstract: 209,133. Atkinson, C. r. Sept. 1, 1922. Switches, without quick action; make-and-break switches, mechanical.-Relates to selector apparatus in which a number of circuits or terminal points at a distant station are adapted to be energized at will either individually or in combination or in a predetermined order with cyclical repetitions and consists primarily in a construction of switch wherebv one or other of the above objects may be attained and secondarily in a system of wiring whereby the number of transmission wires leading to the distant station is reduced to a minimum. Three forms of switch are described, each of which embodies the essential feature of two parallel relatively moving contact carrying members, the contacts mounted on the one member bearing to those on the other the same relation that the graduations of a vernier bear to those on the principal scale. The contacts on the one member are preferably electrically connected. To those on the other are attached the transmission wires. Only one pair of contacts can be engaged at the same time and only a comparatively small movement is necessary to close the circuit in turn to all the wires. The simplest form of wiring will now be described as applied to the lighting at will of one out of say 12 lamps, a, b, c ... at the terminal station. The positive terminals of the lamps are connected together in four groups, viz. abc, def, ghi, jkl, and one wire from each group leads to the home station. The negative terminals are connected in three groups, viz. adgj, behk, cfil and one wire from each leads to the home station. Then by means of two selecting switches, the + source of current is connected to one of the' four groups, e.g. the group def and the - source to one of the three groups, e.g. the group cfil with the result that one lamp only, viz. f is lighted and only 7 transmission wires have been required. In a modified system of wiring three pairs of selecting switches are used in place of one. Considering the + side only of the transmission system, operation of the first switch selects one of l wires. This wire divided into m wires each of which passes through an electromagnetically operated circuit closer and then divides into n wires leading to the + terminals of the lamps. Any other of the l wires similarly divides into m wires which pass through the same circuit closers, and then divide, into n wires each as before. There are in this case lmn lamps. A circuit to a lamp can only be completed when a circuit closer is closed, and the selection of the particular circuit closer is effected by means of the second pair of selector switches which operate to energize the electromagnet of the circuit closer in question precisely as the pair of switches in the previous paragraph operated to light a. particular lamp. Thus by operation of the + switch of the first pair and of both + and - switches of the second pair of selector switches, a particular group of n lamps is selected. Similarly on the - side of the transmission system, operation of the - switch of the first pair and both switches of the third pair, selects another group of lamps. Further, the arrangement is such that the two groups of lamps have only one lamp in common and this lamp consequently is the only one that will be lit. Either of the above systems may be used to energize two lamps in series, one lamp belonging to one set of lamps, and the other to a second set. The + transmission wiring is connected to the + terminals of one set, and the - wiring to the - terminals of the other set, and the remaining terminals of both sets are connected together. The switch shown in Figs. 1, 2, 3, and 5 may be used with the first system of wiring described. A fixed disc 2 carries on each side eight equidistant contacts in the form of spring-supported cones 2b. Mobile discs 3a, 3b are mounted above and below the disc 2 and each carries nine equidistant electrically-connected contacts 3ac or 3bc which contact with the rollers 2b. The + source of supply is connected to the contacts 3ac and the - source to the contacts 3bc. Transmission wires proceed from the top set of cones 2b to the + terminals of the lamps and from the bottom set of cones to their - terminals. The discs 3a, 3b are rotated by control handles 4, 6. The control 6, Fig. 5, is fixed to the disc 3b and has spring catches 6b engaging notches in the discs 3a, 2 locking them in any desired position. The catches 6b may be disengaged by lifting the handle 6. The control 4 is fixed to the disc 3a and includes a knife switch 4b with magnetic blow-out 4a.... It may also have a system of catches similarly to the control 6, so arranged that circuit is broken at the switch 4b when the vernier switches are being moved. The switch shown in Fig. 7 comprises 3 pairs of vernier switches instead of one, and the contacts are mounted on cylinders instead of discs. It is suitable for use with the. modified system of wiring described above. There are three fixed cylinders 2 carrying contact rollers 2b on both sides, and six rotary cylinders P3a, P3b, S3b, S3a, T3a, T3b, closed at the top and carrying corresponding contact strips P3ac, P3bc &c. Each of the rotary cylinders is connected to the one beneath it by epicyclic gearing so that combinations of setting may be made in one act. The upper cylinder may be rotated by hand or may be attached to an observing instrument &c. The control handle for the upper cylinder is shown in Fig. 8 and comprises back and front grips 4d, 6 which actuate respectively a two-way switch and clutch. The two-way switch is actuated against a spring, by movement of a bar 20f, which by means of a link 20g, Fig. 12, rotates a disc 20 carrying two electrically-connected contacts 20k, 201, bringing one of them into connection with one of two contact brushes 20e on the arms of a fixed bridge 20d and so completing a circuit either through a resistance or through the three pairs of vernier switches. The clutch is actuated by the rod 21, Figs. 8 and 9, and comprises essentially jaws 22 which pass through a slot in a cage on the end of the rod 21. The switch shown in Fig. 14 comprises one pair of vernier switches, one switch controlling the + leads and the other controlling the - leads as before, and is mechanically operated so as to energize terminal points cyclically in a given sequence. Considering the top half of the Figure only, reciprocating motion is given by a cam 28<a> to a rod 28 carrying two sets each of ten contact rollers 29 which engage two sets each of nine contact strips 26 connected to terminals 27. Current is led to the rollers 29 by supply strips placed above them through a distributor 32, Figs. 14 and 16, which ensures that the current goes to the top line of rollers during one-half reciprocation, and to the bottom line during the other half reciprocation. The two sets of rollers are symmetrically placed, but the two sets of contacts 26 and terminals 27 are placed out of symmetry to the extent of one division. Also, the nine transmission wires are connected in one order to the top row of terminals 27 and in the reverse order to the bottom row. The distributor, Fig. 16, comprises a drum 32 mounted on a axis 28b and having one complete contact. ring 82a and two half rings 32b, 32c. Three brushes press upon the rings, the centre brush leading the current to the drum, and one of the outer brushes leading it out. Specification 147,899 is referred to.