Head stack assembly with a flexible printed circuit having a mouth centered between arms
View Patent ↗A head stack assembly (HSA) includes a flexible printed circuit (FPC) having a mouth with an upper mouth edge and a lower mouth edge. The FPC includes a first plurality of conductive terminals immediately adjacent the upper mouth edge and a second plurality of conductive terminals immediately adjacent the lower mouth edge. The mouth is bisected by a mouth centerline that is substantially parallel to and substantially equidistant from first and second actuator arms of the HSA. A head gimbal assembly (HGA) is attached to each of the first and second actuator arms. Each HGA includes a flexure tail laminate having a dielectric layer disposed between a plurality of conductive traces and a structural layer. The plurality of conductive traces is electrically connected to either the first or second plurality of conductive terminals via a plurality of openings in the structural layer and in the dielectric layer.
1. A head stack assembly (HSA) comprising:
first and second actuator arms, the first actuator arm being substantially parallel to the second actuator arm;
a first head gimbal assembly (HGA) attached to the first actuator arm, the first HGA including a first flexure tail laminate having a first dielectric layer separating a first plurality of conductive traces from a first structural layer;
a second HGA attached to the second actuator arm, the second HGA including a second flexure tail laminate having a second dielectric layer separating a second plurality of conductive traces from a second structural layer; and
a flexible printed circuit (FPC) having a mouth, the mouth including an upper mouth edge and a lower mouth edge, the FPC including a first plurality of conductive terminals immediately adjacent the upper mouth edge and a second plurality of conductive terminals immediately adjacent the lower mouth edge, the mouth defining and being bisected by a mouth centerline, the mouth centerline being spaced from and substantially parallel to and substantially equidistant from the first and second actuator arms;
wherein the first plurality of conductive traces is electrically connected to the first plurality of conductive terminals via a first plurality of openings in the first structural layer and in the first dielectric layer, and the second plurality of conductive traces is electrically connected to the second plurality of conductive terminals via a second plurality of openings in the second structural layer and in the second dielectric layer.
2. The HSA of claim 1 wherein the mouth centerline is disposed equidistant from the upper mouth edge and the lower mouth edge.
3. The HSA of claim 1 wherein the first plurality of conductive traces is soldered to the first plurality of conductive terminals through the first plurality of openings.
4. The HSA of claim 1 wherein the second plurality of conductive traces is soldered to the second plurality of conductive terminals through the second plurality of openings.
5. The HSA of claim 1 wherein the first flexure tail laminate includes a bend that defines an angular change in the range 6-20 degrees.
6. The HSA of claim 1 wherein the second flexure tail laminate has an unsupported portion having a length greater than 4 mm.
7. The HSA of claim 1 wherein the upper mouth edge and the lower mouth edge are at an angle relative to each other in the range 12-40 degrees.
8. The HSA of claim 1 further comprising a slot through the second flexure tail laminate and a corresponding tab protruding from the lower mouth edge into the slot.
9. The HSA of claim 1 further comprising a hole in the FPC and a corresponding tab protruding from the second flexure tail laminate into the hole.
10. The HSA of claim 1 further including a means for preloading the first and second flexure tails against the upper and lower mouth edges, respectively.
11. The HSA of claim 1 further including a means for positioning the first and second flexure tails relative to the upper and lower mouth edges, respectively.