Inertial latch having an interposer that prevents the head from leaving the ramp load during a shock event

A disk drive includes a disk drive base, a head stack assembly pivotally coupled to the disk drive base, a ramp load coupled to the disk drive base for parking the head, and an inertial latch. The head stack assembly includes a head and a coil portion coupled to the head, the coil portion defining an inner crash stop surface and an outer crash stop surface. The inertial latch includes a unitary latch base coupled to the disk drive base, an inner crash stop and an outer crash stop. The inner crash stop is integrally formed with the latch base and contacts the inner crash stop surface to limit travel of the head in a first direction during a shock event. The outer crash stop is also integrally formed with the latch base, and contacts the outer crash stop surface to limit travel of the head in a second direction during a shock event. The inertial latch further includes a unitary latch base coupled to the disk drive base, an elongated boom pivotally coupled to the latch base, an elongated interposer pivotally coupled to the latch base, a key-shaped post and a key-shaped bore. The key-shaped post and bore define means for pivotally coupling the boom to the latch base and for preventing relative vertical movement between the boom and the latch base. The interposer interacts with the boom during a shock event and contacts the latching surface such that the head is prevented from leaving the ramp load.