Magnetic disk-memory-cartridge hub tester

A magnetic disk-memory-cartridge hub tester comprising,

• a base assembly including a base support member and a vertically pneumatically actuated motor means,
• a source of fluid for said pneumatically actuated motor means including a manifold assembly connected to said motor means,
• an electromagnet and armature assembly having said electromagnet secured to and mounted on said base assembly and including at least one vertically aligned pole piece, said armature being movably mounted for vertical motion, said electromagnet being adapted to traverse said armature vertically towards said pole piece when actuated,
• a spindle assembly mounted on said base assembly and coaxial with the electromagnet assembly to engage said armature and accommodate a lower portion of a hub under test for vertical movement, and
• a proof-ring assembly coupled with the electromagnet assembly to slide axially, vertically in the direction of the spindle along the pole piece of the electromagnet assembly wherein said proof-ring assembly converts the force applied by said motor means into a uniformly distributed force to be applied to the outer edge of said hub under test.

A method of operating a magnetic-disk-memory cartridge hub tester comprising:

• a base assembly including a base support member and a vertically actuated motor means,
• means for driving and controlling said motor means,
• an electromagnet assembly and armature having said electromagnet secured to and mounted on said base assembly and including at least one vertically aligned pole piece, said armature being movably mounted for vertical motion, said electromagnet being adapted to traverse said armature vertically towards said pole piece when actuated,
• a spindle assembly mounted on said base engage said armature and assembly and coaxial with the electromagnet assembly to accommodate a lower portion of a hub under test for vertical movement,
• a proof-ring assembly coupled with the electromagnet assembly to slide axially, vertically in the direction of the spindle along the pole piece of the electromagnet assembly wherein said proof-ring assembly converts the force applied by said motor means into a uniformly distributed force to be applied to the outer edge of said hub under test,
• and in which said method of operation consists of the steps of:
• adjusting said spindle assembly to produce a diaphragm-preload dimension of predetermined known value,
• adjusting the electronic-current source of said electromagnet to produce a magnetic force of a predetermined known value when later energized,
• retracting the proof-ring assembly using said motor means,
• placing a hub assembly on said spindle assembly,
• energizing said electromagnet,
• applying a predetermined lifting force on said hub assembly through said proof-ring assembly by means of said motor means,
• retracting said proof-ring assembly using said motor means, and
• finally reducing the strength of the electromagnetic field until the hub assembly is released from said electromagnet and examining said hub assembly for failure in order to determine whether or not said hub assembly has satisfactorily withstood said lifting force.