Patent GB-1209054-A (GB)
Title: Improvements in or relating to a lock mechanism
IPC: E05B35/08
Filed: 1967-11-22
Abstract: 1,209,054. Locks. E. A. ROSENGRENS A.B 22 Nov., 1967 [23 Nov., 1966], No. 53199/ 67. Heading E2A. A lock mechanism has a bolt operating member 10 and a tumbler assembly arranged in a casing 4, each tumbler of the assembly including an inner and an outer portion 1, 5, the inner portion 1 being pivotally mounted (by a pin 3) in the casing of the lock mechanism and disposed in an opening in the outer portion 5 to engage the outer portion in normal use of the lock, the inner portion including an opening 16 for a key and two arcuate portions 2 which constitute a support for the outer portion, and the outer portion co-operating with a projection 11 on the bolt operating member in the locking position of the tumbler to prevent movement of the bolt operating member, the outer portion including a gate slot 12 for receiving the projection in the unlocking position of the tumbler to permit unlocking movement of the bolt operating member, the tumbler assembly including means 6 for disengaging the inner and outer portions from each other to allow relative movement therebetween for adjustment of the tumbler assembly to accommodate a new key and for re-engaging the inner and outer portions after said adjustment. The two tumbler portions of each tumbler have teeth 17, 18 by which they are normally coupled together for movement by the key the arrangement 'being such that the teeth are disengageable to permit the two portions to be coupled together in a new position to suit a different key; and they are disengaged by the means 6 which is shown as an eccentric disposed in a slot 20 in each outer tumbler portion 5, the slots 20 permitting movement of the tumblers relative to the eccentric when the pairs of tumbler portions are coupled together and rotation of the eccentric moving each outer tumbler portion 5 towards the left as shown to uncouple it from the corresponding inner tumbler portion 1. The eccentric passes through a slot 9 in the member 10 and the eccentric has bosses 7 and 8 which by engagement with the end portions of the slot prevent rotation of the eccentric in the locking and unlocking positions of the member 10; the slot is widened halfway along its length to form recesses 21 and 22 which permit the eccentric to be rotated by providing space for the bosses 7 and 8. Each inner tumbler portion when it is disconnected from its outer tumbler portion is biassed to a central position by a spring 13. To alter the lock mechanism to suit a new key the old key is placed in the mechanism and turned through 90‹ in a clockwise direction from the locking position and this moves the member 10 to a position midway between its locking and unlocking positions so that the eccentric can be rotated; the rotation of the eccentric frees the inner tumbler portions from the outer tumbler portions by moving the outer tumbler portions longitudinally to the left as shown; the old key is then removed which allows each inner tumbler portion to move to its central position under the bias of its spring 13. The new key is then inserted and turned through 90‹ in a clockwise direction which moves the inner tumbler portions to the positions determined by the key hits (which extend on both sides of the key shank) after which the eccentric is returned to its initial position which causes the teeth 17 and 18 of the tumbler portions to become re-engaged in the new positions so that the lock mechanism is then adjusted to the new key.