640,583. Locks. DISSING, H. C. Dec. 9, 1947, No. 32450. Convention date, July 14, 1945. [Class 44] A lock comprises a number of tumblers adapted upon insertion of a key to be moved against the key to a releasing position, the tumblers being formed with stepped surfaces, one step of which is adapted to engage the sides of the key which is formed with recesses allowing the individual tumblers to pass to their correct positions. The lock, shown in Fig. 1, has a pack of pivoted tumblers, alternate tumblers being of different form. The two different forms of tumbler are shown in Figs. 2 and 3. The tumbler 18 has a pivot hole 42 and an aperture 38 having radial. walls 43, 44. A series of steps are formed in one corner of the aperture by arcuate and radial surfaces 45, 46. Horns 50, 51 are provided at the upper, end for cooperation with blade springs 53, Fig. 1, which, on relative movement, tilt the tumblers until one of the steps engages the side face of the key. The other form of tumbler 19 is similar except for the positions of the horns 50<1> and 51<1> and that the steps are formed at the upper corner of the aperture 38'. The key, Fig. 6, is notched on both edges to form a pilot edge over which the steps of each tumbler pass until the correct radial surface 46 meets the side face of the key. Slots 48 formed in the lower ends of the tumblers are angularly related to the position of one of the steps so that with the correct key all the slots are aligned to allow of releasing the lock. The tumblers may be arranged in separate packs corresponding to the profile edge of a certain key, so that the key form required to open a lock may readily be changed. In the lock the tumblers are mounted on a pin 25, Fig. 1, connecting two revoluble plates 16 having slots 40. Fig. 6, to pass the key and inter-engaging tongues 30, 31, 32, Fig. 1. The springs 52, 53 are attached to the casing and adapted when the pack of tumblers is turned by the key to resist the movement by contact with the horns at the upper ends of the tumblers and thereby to rock each tumbler into engagement with the key. As the plates 16 turn under the action of the key the free end 73 of a lever 71 carried by the plates is moved away from a pin 74 allowing a tongue 54 carried on the other end of the lever to move against the tumblers. If all the tumblers are in their correct positions the tongue 54 enters the aligned slots 48 under the influence of a spring 70 acting through a connecting rod 67 pivoted at 66 to the sliding bolt 58. The hooked end 69 of the connecting rod is thereby placed within reach of a hookshaped projection 64 from one of the plates 16 so that further rotation of the key causes retraction of the bolt. The bolt may also be retracted by an inside handle 76, Fig. 5, connected to a rotatable disc 60 running in a slot 59 in the bolt plate. A pin 77 on the disc may be accommodated in either of the slots 78, 79, Fig. 1. A transverse extension 82 on the slot 79 allows the disc to turn to retract the bolt. If, when the bolt is withdrawn by the key, the pin is moved into the slot 81, it serves to retain the bolt in the withdrawn position. If the pin is moved to the upper slot 78 when the bolt is withdrawn it cannot be turned to withdraw the bolt. Specifications 640,584, 640,585 and 640,586 are referred to.