Thermal expansion compensation for disc drive memory

Claim 2

Apparatus for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device comprising means for generating a first electrical sinal having a potential level proportional to the difference between the average temperature of apparatus for supporting said data transfer device at a preselected position with respect to said data storage device and the temperature of one of said data transfer and data storage devices, means for generating a second electrical signal having a potential level proportional to the difference between a set reference temperature and either said average temperature or said temperature of said data transfer and storage devices, and means for combining said electrical signals to provide a temperature compensation signal for regulating a position controller for said data transfer device to compensate for any differences between the location of said preselected position and the positioning by said controller of said data transfer device which would occur if said compensation signal had not been provided.

Claim 3

The apparatus of claim 1 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said effects are a function of the location of said preselected position, and means are included for changing the potential level of said temperature compensation signal to reflect said location of the preselected position with respect to said data storage device.

Claim 4

The apparatus of claim 1 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said means for generating a first electrical signal generates such a signal having a potential proportional to the difference between said average temperature of the apparatus for supporting said data transfer device and the temperature of said data transfer device, and said means for generating said second electrical signal generates such a signal having a potential level proportional to the difference between said set reference temperature and said average temperature of said supporting apparatus.

Claim 5

The apparatus of claim 3 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said means for generating said first electrical signal includes means for detecting changes in the temperature of the data storage device, means for detecting changes in the average temperature of said supporting apparatus, and means responsive to a net relative change in the temperature differential between said data storage device and said average temperature of said supporting apparatus by generating said first electrical signal.

Claim 6

The apparatus of claim 4 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said means for detecting changes in the temperature of said data storage device includes a temperature transducer mounted to intercept gaseous flow which has passed in heat conducting relationship to said storage device during operation of said apparatus to detect changes in the temperature of said gas caused by said storage device and thereby provide a representation of changes in temperature of said device.

Claim 7

The apparatus of claim 4 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein each of said means for detecting changes in the temperature of the data storage device and changes in the average temperature of said supporting apparatus is a thermistor, and said thermistors are connected in parallel between one input terminal of an inverting amplifier and positive and negative potential sources chosen to provide a virtual ground potential level at said one amplifier terminal upon said thermistors having resistances relative to one another representing no temperature differential between said data storage device and said average temperature of said supporting apparatus, the other input terminal of said inverting amplifier being connected to ground whereby any variation in the resistance provided by either one of said thermistors with respect to the other will result in a corresponding potential being produced at the output of said amplifier to provide said first signal.

Claim 8

The apparatus of claim 6 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said means for generating said second electrical signal includes an inverting amplifier having a constant reference potential representative of said reference temperature applied to one input terminal thereof, and a potential applied to the other input terminal through the one of said thermistors which detects changes in the temperature of said supporting apparatus, said reference potential applied to said first input terminal being chosen to provide a potenial at said terminal which is equal to the potential at said second terminal when said average temperature is at a predetermined value with respect to said reference temperature, whereby the output potential of said inverting amplifier will be proportional to the difference between said reference level potential and said other potential caused by changes in the resistance of said thermistor representative of a deviation of said average temperature from said reference temperature.

Claim 9

The apparatus of claim 4 for compensating for the effects of thermal expansion on the positioning of a data transfer device with respect to a data storage device wherein said effects are a function of the location of said preselected position, and means arE included for changing the potential level of said temperature compensation signal to reflect said location of the preselected position with respect to said data storage device.

Claim 10

The apparatus of claim 4 wherein said position controller for said data transfer device includes means responsive to the receipt by said position controller of a positioning control signal which would result in said controller positioning said data transfer device out of a predetermined proximity range about said preselected location by preventing data transfer between said transfer device and said storage device, and said apparatus includes means responsive to said temperature compensation signal by shifting said proximity range to correspond with the corrected positioning of said transfer device with respect to said storage device caused by said temperature compensation signal.

Claim 11

In a random access memory apparatus of the type employing a disc pack for data storage and read/write heads for transferring data between the disc pack and a processing unit, means for detecting changes in the temperature of said disc pack comprising a temperature transducer mounted to intercept air flow which has passed in heat conducting relationship over one of the storage surfaces of said disc pack during operation thereof to detect changes in the temperature of said air caused by said storage surface and thereby provide a representation of changes in the temperature of said disc pack, means for generating a first electrical signal having a potential level proportional to the difference between the average temperature of apparatus for supporting said read/write heads at the preselected position with respect to said disc pack, and the temperature of said disc pack means for generating a second electrical signal having a potential level proportional to the difference between a set reference temperature and either said average temperature or said temperature of said air flow passing over one of the storage surfaces of said disc pack, and means for combining said electrical signals to provide a temperature compensation signal for regulating a position controller for said read/write heads to compensate for any differences between the location of said preselected position and positioning by said controller of said read/write heads which would occur if said compensation signal had not been provided.

Claim 12

In a random access memory apparatus of the type employing a disc pack for data storage and read/write heads for transferring data between the disc pack and a processing unit, means for detecting changes in the temperature of said disc pack comprising a temperature transducer mounted to intercept air flow which has passed in heat conducting relationship over one of the storage surfaces of said disc pack during operation thereof to detect changes in the temperature of said air caused by said storage surface and thereby provide a representation of changes in the temperature of said disc pack, means for generating a first electrical signal having a potential level proportional to the difference between the average temperature of apparatus for supporting said read/write heads at the preselected position with respect to said disc pack, and the temperature of said disc pack means for generating a second electrical signal having a potential level proportional to the difference between a set reference temperature and either said average temperature or said temperature of said air flow passing over one of the storage surfaces of said disc pack, and means for combining said electrical signals to provide a temperature compensation signal for regulating a position controller for said read/write heads to compensate for any differences between the location of said preselected position and positioning by said controller of said read/write heads which would occur if said compensation signal had not been provided.