Disk-pack bolt assembly with attachment indicator

Claim 1

In a disk pack assembly including a plurality of circular magnetically coated disks mounted in spaced coaxial relationship on a hub adapted for engagement with a spindle of a disk-drive having a tapped hole and a surface at a predetermined location with respect to the spindle, and a bolt assembly for attaching said hub to said spindle comprising: a bolt rotatably mounted in said hub having an axially extending orifice, means adapted for engagement to rotate said bolt, and an externally threaded end portion adapted upon rotation of said bolt for engagement with the tapped hole of a said spindle to attach said hub to the spindle; a rod slidably retained within said orifice and movable between a first position and a second position with respect to said bolt; and spring means for urging said rod to said first position, said rod being adapted for engagement with the surface on a said spindle during engagement of the threaded end portion of said bolt with the tapped hole in the spindle to move the rod in opposition to said spring means toward said second position and to said second position upon a sufficient depth of engagement between said bolt and the tapped hole in the spindle to properly attach said disk pack assembly thereto, the improvement wherein said axially extending orifice extends through the end of said bolt opposite said threaded end portion, and said rod in said second position is in a predetermined visual relationship with the end of said bolt opposite said threaded end portion to indicate said sufficient depth of engagemEnt between said bolt and a said spindle to properly attach said disk pack assembly to the spindle.