13 and two gears 14 15 share the same axle 16 there are totally three axles 16 one for each set of code disk 13 and two gears 14 15 as shown in the figures each upper gear 14 is located beneath and connected to its corresponding code disk 13 and each lower gear 15 lies beneath its corresponding upper gear 14 but is not connected to the upper gear 14 between each upper gear 14 and lower gear 15 there exists a spring 19 when the lock 10 is at an unlocked position the springs 19 will be compressed and when the lock 10 is at a locked position the springs 19 will be uncompressed the axle 16 attaches firmly to the upper gear 14 therefore code disk 13 and upper gear 14 will turn at the same pace with axle 16 in one embodiment the upper gear 14 has 12 teeth on the inner side of the outer case 115 there is a clipper that can clip one of the 12 teeth of the upper gear 14 this enables the upper gear 14 the axle 16 and the code disk 13 to turn to one of the 12 position at the same pace this mechanism teeth and clipper is used to lock the code disk 13 and upper gear 14 to make them turn with the axle 16 however the lower gear 15 will not turn with the axle 16 without additional mechanism the upper gear 14 has a protrusion.