Patent GB-147949-A (GB)
Abstract: 147,949. Cohn, A., [Firm of]. April 22, 1919, [Convention date]. No Patent granted (Sealing fee not paid). Electrically operated or controlled fastenings; locks, permutation.-Comprises an electric-switch apparatus in conjunction with a selector enabling current to be switched on for various purposes in such a manner that unauthorized use is prevented. The switch includes two magnets, one for controlling the working circuit and the step-like preparation thereof, and the other for holding open the working circuit if the switch is wrongly manipulated. The device is shown as applied to control an electric door-lock. The selector consists of four insulated metal rings 1, 2, 3, 4, each numbered on the periphery aid being provided with a spring-contact 5. Within these rings is an insulated part 7, having grooves corresponding to the numbers. Each groove is lined with a metal contact 6, and contains a pivoted bellcrank lever 8, one end of which normally contacts with an insulated ring 35. A cotnact spring 9 moves around the contacts 6, an extension 10 at the other end being engaged by a groove in a pressure pin 11, which also drags round the numbered plate 12. The combination is set by rotating rings 1, 2, 3, 4 to the position desired as seen through the aperture in Fig. 1. The contact lever 19 mounted on the switch-wheel 17 is then in contact with ring 1. To move the contact lever to ring 2, the pin 11 is turned until the first number of the chosen combination appears through aperture 13. The pin is then depressed, connecting the sleeve 12a with the leaf spring 14, thus energizing magnet 15 which raise the catch 16<1>, allowing the contact arm 19 to move to ring 2. A similar operation is performed in moving the arm successively to rings 3 and 4, any backward motion of the switch-wheel being prevented by a catch 22. The motion of the switch wheel depresses the lever 20, by a cam 23, through half its range of motion, joining cor.tacts 25. A circuit is thereby made and energizes the safety magnet 21, which by attracting the end 27 of lever 20 releases the lever 28, allowing the spring 29' to draw back the latch-belt 30. The lever 20' is also attracted by the safety magnet 21, and by releasing the catch 22 allows the switch-wheel 17 to restore the contact arm 19 to its original position. If the door is now opened, the release of the cocking-piece attached :o the spring 29<1> from the door jamb removes the spring pressure, and allows a light spring pressing on the latch 30 to restore the end of the lever 28 to its former position under the nose of the lever 20. If the switch is wrongly manipulated, i.e. the pressure pin 11 is depressed when the wrong number appears through the aperture 13, a circuit is established through the bell-crank lever 8 and ring 35, energizing safety-magnet 21. The switchwheel then returns to its original position as before, but as the end 27 of lever 20 is not then fully displaced, this lever remains unaffected. Fig. 13 shows a modification for breaking the current between 21 and 35 in such a case, by making the current-carrying pawl 51 rest on insulating block 53 when the contact arm 19 is moved back to ring number 1.