950,352. Combination locks. EDWARDS CO. Inc. Feb. 14, 1961, No. 5484/61. Heading E2A. A combination lock assembly comprises a code wheel on a shaft driven by an operating knob, the code wheel having a plurality of spaced holes therein corresponding to a plurality of knob positions, a removable drive pin positioned in one of the holes, an idler code wheel rotatably mounted on the shaft and having a pin thereon adapted to contact the removable drive pin to transmit rotation from the shaft to the idler code wheel, the shaft and the driven code wheel having indexing surfaces corresponding to the knob positions, the driven code wheel and the shaft respectively having at least one indexing surface in a position to correspond to one of the positions of the knob, the indexing surfaces on the driven code wheel being adapted to co-operate with the indexing surfaces on the shaft to mount the driven code wheel in a position corresponding to any one of the positions of the knob and to position the pin of the driven code wheel in an indexed relationship to the position of the operating knob, in order to set at least two code numbers of the combination. As shown, the lock mechanism 10 is mounted on a plate 12 through which extends a shaft 20 carrying a removable knob 18. The free end of the shaft, which is provided with twelve indexing grooves 66, carries the following parts: (1) a wheel 36 formed with twelve notches 37 one of which is arranged to correspond in position to that of an indicator pin 40 on the knob 18; a clicker spring 42 co-operating with the notches 37, (2) a code wheel 46 which is freely and rotatably mounted on the shaft and which is separated from the wheel 36 by a freely rotatable washer 50, the wheel 46 being held frictionally against rotation by a spring brake 52, (3) a freely rotatable spacer washer 54, (4) a second code wheel 56 which is freely rotatable on the shaft 20 and is held frictionally against rotation by a spring brake 60, (5) a co-ordinating wheel 62 having ribs 64 which mate with the grooves on the shaft 20, and (6), a driven code wheel 70 having notches 72 which also mate with the ribs on the shaft 20. Rotation of wheel 70 by the shaft 20 is transmitted to code wheel 56 by a pin 76 which is adapted to fit into any one of eleven holes in the wheel 70 when the pin contacts and drives a pin 80 projecting from the wheel 56. Rotation of wheel 56 is transmitted to code wheel 46 by a pin 82 which is adapted to fit into any one of twelve holes in the wheel 56 when the pin contacts and drives a pin 86 on the wheel 46. In operation, knob 18 is rotated through the selected combination to bring notches 88, 90 and 92 positioned on the code wheels 46, 56 and 70 into corresponding position below a spring- loaded pawl 94 which is pivotally mounted on a sliding latch bolt 96. If for example the combination is set for twelve-twelve-one for a twelve o'clock zero position of the fin 40, the combination is worked to open the door to which the lock may be attached, by first rotating knob 18 anti-clockwise through two complete turns thus to positively drive wheels 70, 56 and 46 and bring notch 88 below the pawl 94 and then rotating knob 18 clockwise one full revolution corresponding to the second code number viz: twelve, which returns the fin 40 to the twelve o'clock position and positions notch 90 below the pawl 94. The last code number viz: one, is set by rotating knob 18 one click in anticlockwise direction to bring notch 92 below the pawl 94. A further one additional click of knob 18 in the clockwise direction causes the pawl to slide the bolt from its keeper 106 against a spring 112. A rod 114 on the bolt allows the bolt to be operated without using the combination. The rod 114 may be locked to prevent operation of the mechanism by the combination, by a manually operable pivoted lug 126 on the lock cover 116. The cover also includes a bearing hole for the shaft 20. The cover may be dispensed with and replaced by a strap. The lock includes a scrambling device comprising a lug 136 pivoted on plate 12 and projecting into the space between wheels 56 and 70 to co-operate with pins 142 and 144 thereon such that rotation of the code wheels clockwise misaligns the notch 92 with notches 88 and 90. In modifications of the scrambling device, lug 136 is replaced by a leaf spring and a spring loaded plunger, Figs. 9g and 10 (not shown) respectively. In another arrangement Fig. 18 (not shown) the clicker spring 42 is replaced by a spring loaded ball mechanism and a modified knob arrangement. In a further arrangement, Figs. 12-16 (not shown) the wheels 46 and 56 are replaced by a single idler code wheel.