GB1237692A - Improvements in or relating to lever blocks - Google Patents

Abstract

1,237,692. Locks. O SELLIN. 5 July, 1968 [5 July, 1967 (2)], No. 32209/68. Heading E2A. A lever lock 10 is provided with a plurality of levers 13 mounted on a common lever pivot 17 for actuation by a double bitted key 19 which has different lever steps each for engaging in a cutout 18 in an associated lever, each cutout having a generally rectangular shape adapted to the size of the double lever bit to be inserted therein and provided with substantially arcuate oppositely located curved depressions 18a, 18b on its longitudinal sides, the oppositely directed lever steps of the key each acting substantially simultaneously on one of the arcuate depressions of a lever when the. key is turned, each pair of oppositely located lever steps complementing one another to the same length, in which the curved depressions of all or substantially all the levers are congruent and correspond to outer curves created by arcs of all the different circles described by individual lever steps each about its respective centre relatively to its lever, the centres of adjacent circles being spaced corresponding to the interval between the depth of one lever step and that of the next longer or shorter lever step and lying on an arc centred on the lever pivot, each such interval subtending substantially the same angle at the centre of the arc. As shown, the lever group 13 and a flank lever 15, are each provided with a pocket 23 for engagement with a bolt stump 20 in the path of the bolt 12 when all the pockets are aligned by the key to unlock the lock. The bolt is guided on a stump 27 by a lanket hole 26 and the key steps are arranged to engage the upper and lower depressions in the levers at an angle of about 65 degrees to a line L connecting the lever pivot and the centre line of the key bit. The flank lever 15 is provided with a pin 28 which restores the levers to the locking position under the influence of a spring 29 and a projection 30 on the flank lever 15 prevents withdrawal of the key in a position other than the locked position of the levers. When the key is turned to the 65 degree position a recessed bolt step 19b thereon engages in a recess 31 in the bolt talon to withdraw the bolt. In a modification, Figs. 7 and 8 (not shown) the levers are each provided with a pocket (34), the talon of the bolt is provided with recesses (35), (31), and the key is provided with an additional bolt step (19c) to permit rotation of the key through a further 180 degrees to move the bolt to a further unlocked position or beyond its unlocked position in which it actuates a door latch through a runner (36) or in which a door latch is actuated by the key. In this embodiment, a suitably modified flank lever (38) is used.