Patent GB-1520449-A (GB)
Title: Combination locks
IPC: E05B37/04
Filed: 1975-11-25
Abstract: 1520449 Permutation lock FICHET BAUCHE 25 Nov 1975 [26 Nov 1974 20 Oct 1975] 48328/75 Heading E2A A permutation lock comprises a stack of spaced plates 22 1  to 22 6  between which are sandwiched wards 52 1 ....52 5 . Also between plates 22, and coplanar with wards 52, are catches 75 1 ....75 5 , each catch being attached to an arm 61 of a "rake" assembly. By means of a groove and stud arrangement wards 52 and catches 75 are attached respectively to plates 22 and 61 so that they may slide laterally across them (see Fig. 24). Each catch 75 bears three lugs which can fit into three apertures in the edge of ward 52. The position of each catch 75 along plates 61 is set and maintained by engagement of teeth on an edge of the catch with corresponding teeth on blocking strip 82, also attached to plate 61 and biased by springs 91, 92 towards catch 75. The position of each ward 52 along plate 22 is adjustable by rotation of toothed wheel 50 carried by each plate 22. The lock is "on combination" when the lugs of each catch 75 are in alignment with the apertures on each ward. Fig. 4 illustrates the mechanism for rotating wheels 50 and also for withdrawing the bolt. Tube 180 sheaths a rod 184 corotatable with the tube but able to move telescopically inside it, and bearing a projecting finger 189. Both tube and rod pass through a wheel-window 192, fixed to the wall of the safe etc. but provided with a thread at 195 engaging a ring 197. Ring 197 is attached to a dial 205 which can rotate independently of the ring but not otherwise move, and this ring is linked to rod 184. Rotation of ring 197 causes, by means of the threaded action, rod 184 and hence finger 189 to move longitudinally; rotation of dial 205 causes the rod and finger to rotate about the rod axis. The rod 184 is arranged so that the finger 189 can pass through the centre of wheels 50 and engage slot 51 in each wheel at will, the finger 189 being resiliently mounted so that it can pass through whether or not slot 51 is aligned with it. The position of the finger is known from index marks provided on the surfaces of window 192 and the ring rim 197C, the position for engaging each wheel forming part of the combination. The alignment of the finger and slot at this point is obtained by rotation of knob 205 to the limit of rotation, which is caused by contact between the ward 52 with the lock case, when alignment has obviously been achieved and the finger has sprung in the slot. The other part of the combination (which part is adjustable g.v.) is provided by the rotation of knob 205 necessary to displace each ward 52 into the correct alignment with the corresponding catch 75. Index marks on the knob 205 and flange 199 indicate when this has been acheived. When the wards have been thus aligned, the ring 197 and the knob 205 are further rotated to open the lock. This motion drives finger 189 into engagement with a slot in bush 160 on which is fixed a plate 141. This plate (see Fig. 21) bears on its face studs 145, 146 and arcuate rib 148. Rotation of this plate 141 causes eventually the withdrawal of bolt 122 through the engagement of stud 146 in slots 128 and 129 of the bolt. Before this can happen, however, bolt blocking dog 120 must be moved out of its path. This dog 120 is attached, like click 117, to one limb 110 attached to the "rake" assembly. Rotation of plate 141 forces stud 145 against click 117 and thus depresses limb 110 to lower the dog 120 out the path of a stud (not shown) on the bolt. This depression causes catches 75, also attached to the "rake" via plates 61, towards wards 52, so full unblocking depression can only be achieved if the combination has been properly set and the lugs 77, 78, 79 on the catches are aligned with the apertures on the wards. Further rotation causes withdrawal of the bolt, the bolt being held in by engagement of rib 148 in depression 125 in the bolt. Means are provided to scatter the combination. To this end a toothed pinion 170 is rotatably mounted on bush 160 with a stud 170a projecting into slot 150 in plate 141. Rotation of the plate after withdrawal of the bolt causes the end of slot 150 to engage stud 170a and so rotate pinion 170, the teeth of which engage with a rack 171 and move this sideways. This rack is joined to a bar 174 which passes through slots 58 cut into wards 52 and plates 22. At this point the depressing action on the "rake" has ceased by virtue of stud 145 escaping from click 117 and the "rake" has sprung upwards under the action of springs 105. Thus the catches and the wards are no longer engaged and the sideways movement of bar 174 causes the wards to move out of alignment with the catches. Means to change the combination are also provided. An eccentric cam 222 passes through holes 86 in blocking strips 82. Rotation of this raises the strips out of engagement with catches 75 and these, when the lock has been opened but not scattered, may be moved by rotation of knob 205 to a new position. Return of the blocking strips into engagement with the catches 75 fixes the new combination. Means are also provided to block the bolt if attempts are made to undo the lock by drilling or destruction. This takes the form of a hinged plate 320 ordinarily biased by spring 322 acting against plate 41 into a position out of the path of the bolt. Use of a tool on the casing can force the plate against the spring to the dashed line position (Fig. 35) in which it is retained by the. sprung bolt 326 and in which it blocks withdrawal of the bolt. A second embodiment illustrated in Figs. 27-35 (not all shown) differs from the first in that the coupling between the bush 308 replacing 160 and plate 141 is acheived by a ball 310 and spring 311 in the bush which can engage a slot in the plate. If the combination is not set and the knob 205 is turned the ball 310, is squeezed out of the slot to disengage the coupling and so prevent damage.