Patent ID: 8018688

Claim:
A head stack assembly of a disk drive unit which comprises: a head arm assembly having a head gimbal assembly and a drive arm to be connected with the head gimbal assembly; wherein the drive arm comprises a securing portion, a connection portion and a spacer connecting the securing portion with the connection portion; and an additional head arm assembly having a second head gimbal assembly, a second drive arm to be connected with the second head gimbal assembly, and a voice coil embedded in the second drive arm; wherein the additional head arm assembly further comprises a flexible printed circuit assembly having a flexible printed circuit having a connector attached to one end of the flexible printed circuit and a connection leg extending from one side of the flexible printed circuit; wherein the connection leg has two voice coil pads and a grounding pad formed thereon, the second drive arm is provided with a grounding pin and two connection pins which are electrically coupled with the grounding pad and the two voice coil pads, respectively.