Patent GB-211933-A (GB)
Title: Electric safety combination lock
IPC: G07C9/00
Filed: 1922-11-27
Abstract: 211,933. Cadenel, L. Nov. 27, 1922. Secret contact-combination switches.-In permutation switch arrangements for controlling electrically-operated bolts or other mechanism of doors, safes, &c. such as described in Specifications 27609/12 and 7151/15, a pinion - operated bolt is held against operation by the engagement in one of a pair of recesses in it, of a soft iron gravity-actuated core, lifted to release the bolt by a solenoid when the switch elements are correctly set. Attempts to operate the bolt when the permutation elements are incorrectly set complete a circuit to ring an alarm bell. The bolt p operated by the pinion b of a handle-spindle has a pair of recesses C<1>, C<2> into which drops the soft iron core n of the solenoid e to lock it in either position. The metal bolt is in electrical connection with the metal base plate P, which carries insulated permutation switches h<1>, h<2>, and insulated terminals 1, 2, 3, C. The copper block d co-operating with the spring stud f on the bolt is also insulated from the casing plate P. The terminal 2 is normally connected to the plate P through the contact l and blade spring pivoted at o. The permutation switches comprise metal wheels h<1>, h<2> carrying contact fingers i<1>, i<2>. Gapped contact rings g<1>, g<2> of the same radial distance as! the fingers i<1>, i<2>, situated in the gaps but insulated from the wheels h<1>, h<2>, are also carried by the spindles a of the permutation elements. Each element has a pair of diametrically opposite contact brushes r<1>, r1<SP>1>, and each wheel h<1>, h<2>, has a spring contact R<1>, R<2> snapping into notches in its periphery. The device is wired as shown in Fig. 1. When the permutation elements are set to a predetermined position the contact brush r<1> is resting on the contact finger i<1>, and the brush r<2>, on i<2>. If the pinion now is turned the size of the slots c<1>, c<2> allows sufficient travel of the bolt to bring the stud f into contact with the plate d, completing the circuit through the solenoid e from the battery u, through terminal l, solenoid e, terminal C, contact R<2>, wheel h<2>, finger i<2>, contact r<2>, contact R<1>, wheel h<1>, finger i<1>, contact r<1>, plate d, stud f, bolt. p, casing plate P, contact l, terminal 2, and back to the battery u. This causes the release of the, soft iron core n from the bolt, which can then be fully operated. If the permutation elements have not been correctly set, the contact brushes r<1>, r<2> are in contact with the rings g<1>, g<2>. One such position, with one element correctly set and the other incorrectly set, is shown in Fig. 1. where, if an attempt is made to operate the bolt, the current passes from the battery u, through the alarm bell s, terminal 3, contact r¢, ring g<2> contact r<2> contact r<1>, wheel h<1>, finger i<1>, contact r<1>, plate d, stud f, bolt p casing plate P and back through terminal 2 to the battery. If the permutation element h' had been incorrectly set, the current would have passed through contact r<1>1. By this means, an alarm bell s is rung and the solenoid @ is unaffected the bolt remaining locked. In order to release the core n from the bolt from the inside without setting the combination, a handle k having a spring blade pivoted at o and normally in contact with the casing contact l, is provided. If the, handle is operated to contact the blade with the contact q, the terminal 2 is connected with the terminal C and the current flows from the battery through the solenoid releasing the bolt. To prevent release of the core n by applying a magnet, the solenoid is surrounded by a magnetic sheath m. The bolt also carries a soft iron piece n<1> which is lifted into the hole vacated by the bottom end of the core n to lock the bolt if a powerful electromagnet is applied to lift the core n. The permutation elements are set by the sound of the spring contacts R<1>, R<2> snapping into recesses in the wheels h, " zero " position being found by a finger v contacting with a stud x on the casing. The fingers v are adjustable for changing the combination. To prevent the cover D from being removed to allow access to the permutation elements, it carries hooks w engaged by notched flanges y rigidly secured to the spindles a of the permutation elements. When these are correctly set, notches z are opposite the hooks w and the cover can be removed.