A key blank for making a key for use in a lock and key system including a lock of the kind comprising:
- a housing (204) having a cylindrical bore (203),
- a cylindrical key plug (202) being rotatably journalled in said cylindrical bore, said key plug having a longitudinal key slot (201) and, at a side of said key slot, at least two side locking tumblers (206) in a row cooperating with a side locking means (213) for locking the key plug against rotation in the cylindrical bore,
- at least one of said side locking tumblers (206) having a transversely projecting finger (208) and being mounted in an associated chamber (207) for elevational and rotational movement therein,
- said elevational movement being performed against the action of a force (216) exerted along said chamber (207), and
- said rotational movement of the side locking tumbler corresponding to the associated finger (208) performing a pivotal motion, the rotational movement of the side locking tumbler being limited between two angular positions corresponding to a respective pivotal end position of the finger, and including a key (100) of the kind comprising:
- a longitudinally extending key blade (102), which is insertable into said key slot (201) of the key plug of the associated lock,
- said key blade having a side material region, which is located on at least one side of said key blade and which is confined vertically between a lower, longitudinally extending boundary and an upper, longitudinally extending boundary, said upper boundary being at least partially interrupted by a side code pattern including concavities cut downwardly into said material region with sloping wall portions on each side so as to define a wave-like guiding surface (105) for positively and slidingly catching said projecting finger in the respective concavity and including a ramp surface portion (106) at the tip end (107) of the key blade,
- said wave-like guiding surface (105) engaging with said finger of said at least one side locking tumbler and making the latter follow said wave-like guiding surface, while the key blade is inserted into the key slot and the side locking tumbler is moved elevationally by the interaction of said force (216) and said guiding surface (105), and the finger (208) is caused to pivot sideways between said pivotal end positions, so that, upon frilly inserting the key blade into the key slot, said wave-like guiding surface, including said side code concavities (122,123,124,125), will catch and position the projecting finger (208) of said side locking tumbler (206), and the associated tumbler will allow said side locking means (213) to rotationally release the key plug (202) relative to said housing (204),
- each side code concavity (122,123,124,125) being located at a selected one of a set of predetermined side code concavity locations corresponding to a specific pivotal and elevational position of said finger (208), characterized in that
- in addition to said set of concavity locations, being situated at a number of lower vertical code levels below said upper, longitudinally extending boundary and being distributed also in the longitudinal direction, there is at least one additional, longitudinally extending side code segment located at an extra, upper code level substantially at said upper boundary of said side material region, above said lower vertical code levels, and forming an upper shelf surface for supporting said projecting finger above said lower vertical code levels, said side code segment being formed with a longitudinally extending supporting surface located on the side portion configured towards the tip end of the key and on the side portion configured away from the tip of the key with a smoothly adjoining retaining surface extending upwards and being disposed on the supporting surface of said side material, said extra, upper code level representing a distinct extra code, corresponding to a specific, higher elevation of the associated side locking tumbler and, upon fully inserting the key blade into the key slot, retaining the projecting finger thereof in a forward pivotal end position pointing towards the tip end of said key blade, whereby the number of possible code combinations is increased;
- and
- wherein said upper shelf surface is located below an upper edge portion of the key blade, said upper edge portion also having a material region for a code pattern.