Temperature compensation system for a magnetic disk memory unit

Claim 2

A temperature compensation system for a magnetic disk memory unit having a disk of predetermined material mounted on a hub which is rotatable by a drive unit such drive unit having read/write heads which are positionable over any one of a plurality of tracks on a disk of said memory unit said drive unit including a servo system for positioning said heads over a predetermined track said temperature compensation system comprising: a linear motor included in said servo system having a linear radial movement relative to said rotatable disk; transducer means included in said servo system responsive to movement of said linear motor for producing an actual position signal which may be compared with an external reference position signal to control said linear motor; carriage means for coupling said linear motor to said heads and said transducer means; said transducer means including a linear scale and a movable pickup head said scale being substantially composed of the same material as said disk and being fixedly mounted within said drive unit at only one end of the scale which lies in substantially the same vertical plane as where the disk is mounted on its hub said linear scale also being aligned in a radial direction whereby said disk and scale are free to expand in a similar manner; and means coupled to said carriage for mounting said read/write heads and transducer pickup heads in substantially the same vertical plane.

Claim 3

A temperature compensation system as in claim 1 together with means for directing a common air flow over said disk and scale to minimize the vertical temperature gradient.

Claim 4

A temperature compensation system as in claim 2 where said air flow means includes a common bowl which contains said disk and scale.

Claim 5

A temperature compensation system as in claim 1 where said drive unit includes a drive motor mounted in a housing for driving said hub of said memory unit said scale being fixedly mounted to said motor housing said housing and hub being composed of the same material as said disk and scale.

Claim 6

A temperature compensation system as in claim 4 in which said material is aluminum.

Claim 7

A temperature compensation system as in claim 1 where said means for mounting said read/write heads and transducer pickup includes individual support fingers composed of the same material and affixed to said carriage in substantially the same vertical plane.

Claim 8

A temperature compensation system as in claim 6 where said material is steel.

Claim 9

A system as in claim 1 where both said linear scale and said pickup head include respectively first and second sets of parallel conductors.

Claim 10

Apparatus for accurately controlling the positioning of read/write heads relative to a recording surface in a disk memory unit comprising, a spindle member for supporting a disk record member having a predetermined coefficient of thermal expansion, motor means for rotating said disk member, carriage means having a predetermined coefficient of thermal expansion and movable in a predetermined direction relative to said disk member for supporting and positioning said read/write heads relative to said disk member, motor means for driving said carriage means in said predetermined direction, a first plurality of substantially parallel conductors, a scale member having a coefficient of thermal expansion substAntially equal to the coefficient of thermal expansion of said disk member for supporting said first plurality of parallel conductors, means for connecting said scale member at one end thereof in a predetermined relationship relative to said disk member, the opposite end thereof being freely expandable in a similar relationship with said disk member in response to temperature gradients, a second plurality of substantially parallel conductors, a transducer member for supporting at one end thereof said second plurality of parallel conductors, means for connecting said read/write heads to said carriage means, means for connecting said transducer member to said carriage means at the end thereof opposite said conductors with said conductors on said transducer member being in operative relationship with the conductors on said scale member and said transducer member being freely expandable in a similar relationship with said means for connecting said read/write heads in response to temperature gradients, and means responsive to movement of said transducer member relative to said scale member for generating actual position signals indicative of the positioning of said read/write heads relative to said disk member for controlling movement of said carriage means.

Claim 11

Apparatus for accurately controlling the positioning of read/write heads relative to a recording surface in a disk memory unit comprising, a spindle member for supporting a disk record member having a predetermined coefficient of thermal expansion, motor means for rotating said disk member, carriage means having a predetermined coefficient of thermal expansion and movable in a predetermined direction relative to said disk member for supporting and positioning said read/write heads relative to said disk member, motor means for driving said carriage means in said predetermined direction, a first plurality of substantially parallel conductors, a scale member having a coefficient of thermal expansion substAntially equal to the coefficient of thermal expansion of said disk member for supporting said first plurality of parallel conductors, means for connecting said scale member at one end thereof in a predetermined relationship relative to said disk member, the opposite end thereof being freely expandable in a similar relationship with said disk member in response to temperature gradients, a second plurality of substantially parallel conductors, a transducer member for supporting at one end thereof said second plurality of parallel conductors, means for connecting said read/write heads to said carriage means, means for connecting said transducer member to said carriage means at the end thereof opposite said conductors with said conductors on said transducer member being in operative relationship with the conductors on said scale member and said transducer member being freely expandable in a similar relationship with said means for connecting said read/write heads in response to temperature gradients, and means responsive to movement of said transducer member relative to said scale member for generating actual position signals indicative of the positioning of said read/write heads relative to said disk member for controlling movement of said carriage means.