Patent GB-506483-A (GB)
Title: Improvements relating to selecting switches of the kind used in communication systems
IPC: H01H67/16
Filed: 1938-09-30
Abstract: 506,483. Electric selectors. FIDES. GES. FUR DIE VERWALTUNG UND VERWERTUNG VON GEWERBLICHEN SCHUTZRECHTEN. Sept. 30, 1938, No. 28491. Convention date, Sept. 30, 1937. [Class 40 (iv)] In a selector having an individual driving motor and wipers which are not in engagement with bank contacts during the selecting operation, the movement of the wipers into and out of engagement with the selected bank contacts is brought about by the motor. The operation of the selector is completely controlled by a lever 11 and a rotary shaft 8 which are electrically controlled by the arrangement shown in Fig. 6. The wipers 3, 4 and 5 are mounted on a frame 2 free to move vertically relative to a shaft 1, and to rotate with it. When the lever 11 is raised by the operation of a coupling magnet, wheel 10 driven from shaft 8 is coupled to a worm 13 engaging a rack 14 on the frame 2 which is thereby raised one step for each turn of the worm. When the vertical setting is complete lever 11 is dropped and wheel 10 is coupled to the part 40 which drives the wheel 17 through the wheels 15 and 16. At this stage, the frame 2 is coupled to rotate with wheel 17 by means of a rod 18 engaging a hole in the wheel. Rotation of the frame 2 brings a grooved wheel 33 at the bottom of rod 18 into engagement with a curved member 30, Fig. 2, secured to the lever 11. When the testing wiper 3 finds a free outlet, lever 11 is again raised by the coupling magnet, and the wheel 33 and rod 18 are also raised by member 30, thereby releasing the connection between the wheel 17 and the frame 2. At the same time the rod 18 enters a hole 50 and fixes the frame. When the wheel 33 engages the member 30, the lever 11 cannot be raised sufficiently to decouple wheel 10 and part 40. Further rotation of shaft 8, therefore, causes wheel 17 and cams 19 on a collar 20 secured to the wheel to rotate relative to the frame. The cams 19 engage the arms 28 and 29 of the wipers 5 and 4 and allow a spring to press them into engagement with the bank contacts 23 and 22 respectively. On release of the connection, the cams rotate further and withdraw the wipers from the bank contacts, lever 11 is released and wheel 17 is turned until the rod 18 again engages the hole in the wheel. The frame is then restored to its normal position in known manner. In the modification shown in Fig. 4, the individual motor drives the pinion 54 and a gear wheel 55. Vertical stepping is obtained by means of a worm 51 on the shaft 50 which engages a key 57 secured to the wiper frame. This frame is meanwhile prevented from rotating by a stop 67 which engages a hole in the fixed frame and when vertical motion is complete, the coupling magnet operates, raises the shaft 63 causing gear-wheels 64 and 65 to engage, and raises the member 66 to release the stop 67 from the fixed frame work and to engage the stop with a hole in wheel 65 so that the wiper frame can be rotated. When an outlet has been selected, the coupling magnet releases and the wiper frame is again fixed by the stop 67. Rotation of the shaft 50, then causes the cams 70 to bring the wipers into engagement with the bank contacts. A catch, not shown in Fig. 4, is provided to hold the wipers in their retracted position until selection has been completed, as during the vertical stepping the cams rotate. In the circuit shown in Fig. 6, suitable for the selector shown in Fig. 1, KM is the coupling magnet and M(i) and M (ii) are the two magnet windings of the driving motor. The motor is of a known kind in which the armature is rotated by energizing the two windings alternately. When the selector is seized, relay A and the slow release relay C are operated. Slow-to-release relay V2 is also operated through the off-normal contact 6w of the selector. At the beginning of an impulse, magnet KM is operated to couple the motor with the worm 13, and the relay V1(i) is operated. The magnet winding M(ii) is also energized and the motor makes a quarter of a rotation, raises the selector half a step, opens contact 12 and closes contact 13. At the end of the impulse, M(i) is energized and the motor turns and completes the step. At the end of an impulse train, V2 and KM release, but V1 remains operated through off-normal contact 18k operated on the first vertical step of the selector. On release of V2, the motor rotates under the control of its own contacts 12, 13 until a free outlet is found whereupon test relay P operates, causing S to .operate short-circuiting. V1(ii) and energizing both M(i) and M(ii) so that the motor cannot move. Operation of S' energizes KM again to fix the wiper frame prior to movement of the wipers into engagement with the bank contacts. When KM is energized, the motor is again free to rotate and the wipers are allowed to engage with the bank contacts. When V1 eventually releases, the motor is switched out of circuit. On the termination of the connection relays A, C, P and S and therefore KM release, and V1 is again operated through off-normal contact 18k. Operation of V causes the motor to run again under the action of its own contacts 12, 13 to withdraw the wipers. Eventually, as KM is no longer operated, the rod 18 falls into the hole in wheel 17 and the frame is then rotated to a position clear of the bank. This closes a shaft contact w111 and w122 and P is again operated, thereby operating S and KM. Operation of KM energizes both M(i) and M(ii) and stops the motor. The release spring of the selector now takes effect and returns the wiper frame to normal position.