Patent GB-160813-A (GB)
Title: Improvements in or relating to electric switching or like devices
IPC: E05B45/06
Filed: 1920-07-09
Abstract: 160,813. Cohn, A., [Firm of]. April 23, 1919, [Convention date]. No Patent granted (Sealing fee not paid). Secret contact-combination switches. -Comprises an electric switch apparatus in which two circuits are arranged to be closed alternately, the first controlling lamps, machinery, lockmechanisms or the like. To prevent unauthorized operation the first circuit is closed in a predetermined manner by successive step like switching operations of a secret-contact switch, the second circuit being completed after incorrect manipulation. The selective switching device, as shown in the control of a door lock, comprises four insulated metal rings 1, 2, 3, 4, each numbered on the periphery and provided with a spring contact 5. Within these rings is an insulating body 7, having longitudinal grooves corresponding to the ring numbers, each groove having a metal lining 6 carrying pivotally a bell crank lever 8, one end of which normally contacts with an insulated ring 35. Setting of the rings to a combination visible through an aperture s raises corresponding levers 8, breaking their contact with the ring 35 and making contact with the ring contacts 5. A spring contact 9 moves over the inner faces of the extended metal linings 6, this contact being secured to a plate 12 carrying a central metal sleeve 12a, an extension 10 of the contact spring passing through the sleeve 12a. A contact lever 19 moves over the rings 1, 2, 3, 4, said lever being secured to a ratchet plate 17, controlled by electromagnets 15, 21. The closing of the circuit is effected by stages as follows :-A grooved central pressure pin 10 is inserted and the plate 12 is moved until the first combination number appears through the aperture 13; the pin is then depressed against the action of spring 12b causing contact between the sleeve 12a and the flat spring 14, thereby completing a circuit through magnet 16 causing the arm 16<1> to move the ratchet plate 17 by one tooth 18, thereby moving contact lever 19 to ring 2. This process is repeated for the other numbers. When the final stage is complete the lever 20 is displaced by the cam 23 on the plate 17 sufficiently to join contacts 25 completing the controlling circuit through magnet 21, which attracts the armature 20, the nose 27 releasing the lever 28, allowing the spring 29<1> to shoot back the latch bolt 30. The energization of magnet 21 also attracts armature 20<1> releasing the catch 22 and allowing the spring 36 to restore the ratchet wheel to its initial position. Depressing the pin 11 during the switching movements with the wrong number showing through the aperture 13 causes a similar restoring action of the wheel 17 by energization of magnet 21 through the ring 35, but as the cam 23 has only partially displaced the lever 20, at this stage this lever remains unaffected by the magnet 21, and the lock is not released. In the Specification as open to inspection under Sect. 91 (3) (a) it is stated that the completion of the circuit through the ring 35 brought into operation an electric alarm device to indicate incorrect manipulation of the switching mechanism. This subject-matter does not appear in the Specification as accepted.