Patent attributes
A lock has a locked condition and an unlocked condition comprising a barrel with a circular bore having three splines. A cylindrical plug is adapted to reside in the bore. First, second and retaining tumblers are positioned in tumbler slots, with the first and retaining tumblers biased in one direction toward the first spline and the second tumbler biased in the opposite direction into the second spline. When a first key is inserted, the first and second tumblers are moved against the bias so they retract from the respective splines and the plug can be rotated from the locked and unlocked conditions. When a second key is inserted while in the unlocked condition, the first, second and retaining tumblers are moved so the respective tumblers are either positioned in the third longitudinal spline or fully retained in the plug and the plug can be retracted axially from the barrel.
