639,024. Barrel locks. STERNER, B. Nov. 18, 1947, No. 30616. [Class 44] In a barrel lock of the kind comprising a casing 1, Fig. 3, a barrel 2 rotatable in the casing, axially slidable push-pieces 7 in the barrel displaceable against spring action by the bits of a key inserted in a key-way 13 of the lock and combination pieces 20, Figs. 2, 4, axially slidable in the casing, the push-pieces being capable of being coupled to the combination pieces for changing the combination of the lock and after withdrawal of the key being moved by their springs 16 into locking positions in which they engage the combination pieces, the combination pieces are held in the axial positions to which they have been set by the interengagement of teeth 19 thereon and teeth 18 on the surface of the barrel the teeth being of square or rectangular sections so that radial play between the teeth does not result in play in the axial direction of the barrel. The push-pieces 7 may be for example six in number and are each of U-shape having a guiding portion 9 sliding in an axial bore in a cylindrical wall 8 of the barrel and an outer limb 11 having two projecting parts 15 with a gap between. The limbs 11 are guided in axial slots 12 in the surface of the barrel. The key is of flat section and fits in the key-way 13, axial ribs thereon fitting in side slots 14 to engage the parts 9 and displace the push-pieces 7. The combination pieces 20 are slidably mounted in T- shaped slots 21 formed axially in the internal wall of the casing 1 and carry teeth 19 normally engaging une circumferential teeth 18 on the surface of the barrel between the slots 12 whereby they are held against axial movement except when aligned with the slots. This position is called the "neutral" position. In the locked condition, e.g. before the key is inserted (see Fig. 3) the rearward parts 15 of the push-pieces abut the sides of the combination pieces to prevent rotation of the barrel. Similarly if a wrong key is inserted in the key way 13 the bits may move the push-pieces too far so that the forward parts 15 stand in the path of the combination pieces. The correct key moves the push-pieces 7 to a position where the combination pieces may pass through the gaps between the parts 15. When the barrel is in the neutral position the combination pieces must be engaged between the parts 15 of the push-pieces 7 and are free to slide therewith when the key is withdrawn. The bits 23 of the key 22, Fig. 2, may be fixed or adjustable. If a key having a new combination is inserted in the neutral position the combination pieces 20 are displaced to new positions where they are again retained by the interengagement of the teeth 18, 19. The barrel is free in the neutral position and to prevent the key with the new combination being accidentally rotated during insertion four plates 31, 32, 33, 34 are provided engaged in a peripheral slot 30 of the barrel opposite plates 31, 33 being fixed by pins 37, 38 to the casing and intermediate plates 32, 34 being slightly movable and controlled by an outside ring 46 having connecting arms 47 and biassed by springs 48 so that there is normally no gap in the neutral position i.e between plates 31, 32 and 33, 34. The plates 31, 33 have slots 41 in line with the key slot 13 in the initial position of the barrel so that the key can be inserted. Transverse slots in the sides of the key allow the key to turn past the plates. Rotation through 30 degrees brings the barrel to the neutral position, Fig. 4, and rotation of the ring 46 opens gaps between plates 31, 33 and 33, 34 so that the key can be withdrawn, its combination changed e.g. by movement of the ribs and reinserted to move the combination pieces to new positions. Slots 51 in the plates 32, 34 allow the key to be withdrawn in the unlocking position of the barrel in which it is then retained. The push pieces 7 have sockets in the forward ends to engage the pins 37, 38 when in the forward neutral position so that the barrel cannot move until the key is reinserted. Specification 515,521 is referred to.