GB851357A - Security locks - Google Patents

Abstract

851,357. Barrel locks. PATRIGNANI, T. Nov. 5, 1956, No. 33650/56. Class 44. In a plug and cylinder unit for a lock, the plug has at least one tumbler with a hole for the key to pass through, and can be slid axially, when the key is inserted, between a free position in which it can be rotated to actuate the lock and a fixed position in which rotation of the plug is impossible. The cylinder 1 has a series of inwardly extending annular ribs 2, separated by annular grooves 3; and guide washers 4, encircled by the ribs 2, are each provided with cross-shaped apertures 6 from the arms of which extend radial gutters 5. Plate tumblers 8 separate the guide washers and are each provided with an eccentric aperture 24. Balls 9 within each aperture are constrained to move in the respective channels formed by respective pairs of parallel gutters in the adjacent guide washers; and a fifth ball 10, set in a hole in each tumbler 8 and also constrained to move in one of these channels, serves as a sliding pivot for the respective tumbler. A key 7 of cross-shaped section formed by four ribs of wavy profile is so shaped that, when inserted centrally through the guide washers with the ribs engaging the apertures 6 therein, the tumblers 8 are urged, by the ribs engaging the balls which in turn engage the tumbler apertures, into coaxial relationship with the guide washers. The system of guide washers and tumblers, constituting the plug, may then be displaced axially against a spring 19, by pressure on the key, so as to disengage projections 13 and 21, formed on the end members 11, 20 of the plug, from notches in the outermost ribs 2a, 2b, and thus enable the plug and a rod 18 attached thereto to be rotated to release a bolt. The ribs 2 may comprise only arcs of an annular ring, and the tumblers and guide washers need not be circular. In a modification the tumblers are so shaped, Figs. 9 and 10 (not shown), as to have two or more positions in which no overlap with the ribs 2 occurs, and thus the lock may be operable by two or more different keys. Means are also described for rigidily securing the guide washers into a composite block, Fig. 13 (not shown), so as to reduce the risk of distortion of the lock elements.