Cylinder lock with multiple, supplemental locking elements and associated key

A method of forming a key from a key blank, wherein the key is operable for opening a lock comprising (i) a plug with a keyway formed therein, (ii) a housing having a bore within which the plug is rotatably disposed, (iii) a sidebar disposed within a sidebar opening formed in the plug and configured for radial movement with respect to an axis of rotation of the plug for engaging a sidebar groove formed in a wall of the bore formed in the housing for controlling rotation of the plug within the housing, (iv) primary pin assemblies aligned with the keyway for partially controlling rotation of the plug within the housing and for partially controlling radial movement of the sidebar within the sidebar opening, wherein each primary pin assembly includes a tip extending into the keyway, (v) one or more secondary pins for partially controlling radial movement of the sidebar within the sidebar opening, wherein each secondary pin has a pin body disposed in a secondary pin hole formed in the plug at a laterally offset position from the keyway, and wherein each secondary pin includes a transverse projection extending from the pin body into the keyway, and (vi) at least one supplemental sidebar control element for partially controlling radial movement of the sidebar within the sidebar opening, wherein each supplemental sidebar control element is disposed within the plug at a laterally offset position from the keyway, and wherein each supplemental sidebar control element includes a key-engaging portion that extends into an associated lateral relief formed in the keyway and is laterally offset from the transverse projection of each secondary pin, the key blank comprising a key blade configured to be inserted into the keyway and including a primary top edge, a bottom edge, first and second opposed sides extending between the primary top edge and the bottom edge, a rib extending longitudinally along at least a portion of the first side, and a groove opposite the rib and extending longitudinally along at least a portion of the length of the second side, the method comprising:

• forming primary bittings on the primary top edge for contacting the tips of the primary pin assemblies extending into the keyway and manipulating the primary pin assemblies of the lock when the key formed from the key blank is inserted into the keyway;
• forming secondary bittings on a secondary top edge of the rib for contacting the transverse projection of each secondary pin and manipulating the secondary pin of the lock when the key formed from the key blank is inserted into the keyway;
• and
• providing at least one movable shuttle pin within a through-hole extending through the key blade from the first side to the second side, wherein the shuttle pin is configured to engage a multi-level ridge projecting from a side of the keyway and aligned with the groove of the key blade as the key formed from the key blank is inserted into the keyway to move the shuttle pin from a first position, where one end of the shuttle pin extends into the groove, to a second position, where an opposite end of the shuttle pin extends from the first side of the key blade into the lateral relief to contact the key-engaging portion and actuate the supplemental sidebar control element, and wherein the secondary bittings are configured to not engage the key-engaging portion of the supplemental sidebar control element as the key formed from the key blank is inserted into the keyway.