Variable camshaft timing system

A variable camshaft timing (VCT) system, comprising:

• an independent camshaft phaser, receiving input from a crankshaft of an internal combustion engine, having an output coupled to an outer concentric camshaft;
• and
• a dependent camshaft phaser comprising:
• a camshaft plate coupled to the outer concentric camshaft;
• a plurality of pivotable arms that engage the camshaft plate through one or more pins;
• a plurality of secondary pivotable arms that pivotably connect to the plurality of pivotable arms;
• a half-Oldham plate, pivotably coupled to a distal end of the secondary pivotable arms, having a key slot;
• and
• a key, rigidly coupled to an inner concentric camshaft, that is received by the key slot,
• wherein the key moves relative to the key slot to permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in one radial direction, the pivotable arms and the secondary pivotable arms permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in another, different radial direction.