Patent GB-305644-A (GB)
Filed: 1928-09-12
Abstract: 305,644. Boder, E. Feb. 10, 1928, [Convention date]. Switching systems.-Electric circuits, such as those for street lighting systems, for heating systems, or for controlling the change-over of multiple tariff meters, are operated by switching- apparatus which is situated at secondary stations and is given impulses periodically from a central station. The impulses may be given once an hour or at predetermined irregular intervals. Means are also provided for bringing the secondary stations, after failure of the current, into correct relation again with the central station. A time disc 30, Fig. 1, at the central station is rotated by clockwork once in twenty-four hours and -carries pins 32, 32<1> which, once an hour, trip an arm 35 or 35' to move the contact arm 38 to left or right to bridge contacts 38', 38", or 38', 38<111> Once an hour an impulse is thus sent to a winding 55, Fig. 2, at each secondary station J so that a pawl is retracted over a tooth of a ratchet 57, whereby on the return stroke by a spring 57<1> this ratchet, through gearing, rotates a time disc 1/24th of a revolution. This disc 52 carries adjustable arms 54 which at the predetermined hours rotate a switch 58 one step to control the heating or lighting &c. circruit. J<1> shows a modified secondary station in which a small motor 59 replaces the winding 55. At the hourly bridging of contacts 38<1>, 38<11> or 38', 38<111> the impulse is given through the following means. A switch D operated by a motor 45 and spring-coupled shafts 44, 42, includes two arms 39, 40 at right angles to each other, and an insulated segment 41, Fig. 1<a>, for bridging contacts 39<1>, 39", and 40', 40", and 41<1>, 41<11> (or 41<111>, 41<1111>) respectively. This switch D may be replaced by the manual switch 46, in which case switch 48 is moved from contact 48<1> to contact 48". When desired a second manual switch 49 may replace the clock switch C and give the motor 45 any desired number of impulses. When a pin 32<1> moves the arm 38 to close contacts 38<1>, 38<11> the motor 45 is energized through a circuit a, 45, b, 41<1>, 41, 41<11>, c, 38", 38, 38<1> and d, the shaft 42 is rotated, bridge 40 is opened, and bridge 39 closed to energize the circuit F, 39<1>, 39, 39<11>, 48, B, B' (or B<11>) of the secondary stations windings 55 (or motors 59). When the shaft 42 rotates 90‹ to close the bridge 39 the segment 41 takes' up the dotted line position of Fig. 1a, so that the motor 45 remains energized. The shaft 42 rotates another 90‹ to open bridge 39 and close bridge 40 leaving the parts ready for the next impulse. During this action the segment 41 finally left the contacts 41<1>, 41<11>, and closed the alternative contacts 41<111>, 41<1111>. The action of spring coupling 43 is a snap one, causing the shaft 42 to rotate in steps of 90‹. In the normal position shown the circuits are locked against operation by being connected to the neutral conductors. The full lines A, A' illustrates a two-phase system. For three-phase working the dotted conductors at the top of Figs. 1 and 2 are added. The impulses may be sent at intervals of 5 to 10 minutes. The pins 32, 31<1> may be placed for predetermined irregular intervals. If the main feeding circuits A, or A' fail (e.g., are interrupted at x and y or x' and y<1> for repairs) then on the resumption a manual switch 50 or 50<1> is closed until the discs 52 are again in agreement with the central disc 30. Fig. 3 shows an arrangement in which the manual switch 49 for giving correctional impulses is replaced by automatic means. The shaft 31<1> of the disc 30. carries insulated slip rings 79, 79' connected to contacts 80', 80<11> on an arm 82 rigid with the shaft 31<1>, A shaft 81 on this arm 82 carries an insulated rigid arm 80 and a rigid disc 85 connected by a spring 84 to a loose disc 83 having a pin 83' which coacts with projection 88 on a time disc 87 driven by winding 89 and ratchet 91. The coupling 84 gives a snap motion to the arm 80. If the current fails, the time disc 30 continues but the secondary time discs and the device K (87, 91, 89) are halted. After a short interval the arm 82 overtakes the disc 87 so that the pin 83' is turned by the projection 88 and the blade 80 closes contacts 80', 80<11>. The pin 83<1> moves free of the projection 88 and the arm 82 moves on with the bridge 80 closed until the current is again on. Then a circuit a, 45, b, f, 79<1>, 80', 80, 80", 79, g, 38<1>, d is energized to rotate motor 45, which thereafter operates bridges 39, 40 to give successive and frequent impulses to the secondary stations and device K until the disc 87 returns to correct relative position. In this position the projection 88 again rotates pin 83' and thereby opens the circuit at 80. In a modification, when the current fails the switch arm 38 is locked against further oscillation until a disc, similar to disc 87 of Fig. 3, is again in correct relationship with the main time disc 30, impulses being transmitted while the discs are regaining their correct relationship. Specification 292,603 is referred to.