GB646486A - An improvement in cylinder locks - Google Patents

Abstract

646,486. Barrel locks. SALMIVUORI, J. E. July 1, 1948, Nos. 17779 and 17780. Convention dates, Feb. 7, 1947, and Feb. 8, 1947. [Class 44] In a barrel lock of the type comprising an outer casing 2, Figs. 1, 4 and 5, and a barrel 4 connected to the lock mechanism, containing a series of independently rotatable circular disks 12, each provided with a primary notch 19 on its periphery, which when aligned by use of a key receives a bar tumbler 25, adapted in another position to lock the barrel 4 to the casing 2, at least some of the discs have a secondary notch 20 to receive a secondary tumbler bar 26 in the unlocking position. Fig. 4 shows the lock in section, the locking bars 25. 26 being in the locking position engaging in notches 23, 24 in the casing 2. To prevent picking a greater clearance is allowed between the bar 26 and its notch 24 than between the bar 25 and its notch 23. This ensures that external pressure cannot be put on the secondary bar by rotation of the barrel until the primary bar is engaged in a row of notches, this preventing further rotation of the discs. A number of false notches 34 are provided to lessen the chance that the primary bar has been engaged in the correct notches. The discs are turned to the correct position relative to the barrel 4 by a key 28, Figs. 12 and 13, engaging in sector-like openings in the discs. When the two correct sets of notches 19, 20 are aligned the bars 25, 26 fall into them as shown in Fig. 5, and free the barrel which, on further rotation of the key is turned by abutment of a projection 27 on one or some of the discs abutting the edge of a slot 15 in the wall of the barrel. When turned back to the locking position the barrel is arrested at the correct position by a spring blade 9, Fig. 1, secured to the casing 2 and engaging a notch in the end of the barrel 4. The tumbler bars may be guided by pins slidably mounted in radial bores in the barrel 4. The false notches, although of the same shape as the correct notches are so spaced that the bars may only be received in a particular pair of notches. In another form, Fig. 15, the bars 25b, 26b are mounted on arms 35, 37 extending along the periphery of the barrel, the arm 35 of the primary bar underlying the bar 26b so that the primary bar cannot move to an unlocking position before the secondary bar.