Linear actuator for magnetic disc drive and the like

Claim 2

A compact linear actuator for moving pickup heads relative to a disc in a magnetic disc drive comprising a generally cylindrical housing of a magnetic material including a plurality of magnets mounted to the inside surface of said housing, said housing being open at each end, a generally cylindrical bobbin including a coil wound on the periphery of said bobbin, said bobbin being positioned within said housing and linearly movable therein with said coil in close proximity to said plurality of magnets, an annular ring of a magnetic material having a central opening and providing first magnetic flux transmission means attached to one end of said housing in a peripheral portion of said housing to provide a magnetic path for said magnets and prevent magnetic flux leakage, a plate of a magnetic material providing a second magnetic flux transmission means attached to the other end of said housing to provide a magnetic flux path for said magnets and prevent magnetic flux leakage, and pickup head carriage means extending through said central opening and attached to said bobbin for linear movement with said bobbin.

Claim 3

A compact linear actuator for moving pickup heads relative to a disc in a magnetic disc drive comprising a generally cylindrical housing of a magnetic material including a plurality of magnets mounted to the inside surface of said housing, said housing being open at each end, a generally cylindrical bobbin including a coil wound on the periphery of said bobbin, said bobbin being positioned within said housing and linearly movable therein with said coil in close proximity to said plurality of magnets, an annular ring of a magnetic material having a central opening and providing first magnetic flux transmission means attached to one end of said housing in a peripheral portion of said housing to provide a magnetic path for said magnets and prevent magnetic flux leakage, a plate of a magnetic material providing a second magnetic flux transmission means attached to the other end of said housing to provide a magnetic flux path for said magnets and prevent magnetic flux leakage, and pickup head carriage means extending through said central opening and attached to said bobbin for linear movement with said bobbin and at least partially retractable within said housing through said central opening.

Claim 4

A compact linear actuator for moving pickup heads relative to a disc in a magnetic disc drive comprising a generally cylindrical housing of a magnetic material including a plurality of magnets mounted to the inside surface of said housing, said housing being open at each end, a generally cylindrical bobbin including a coil wound on the periphery of said bobbin, said bobbin being positioned within said housing and linearly movable therein with said coil in close proximity to said plurality of magnets, an annular ring of a magnetic material having a central opening and providing first magnetic flux transmission means attached to one end of said housing in a peripheral portion of said housing to provide a magnetic path for said magnets and prevent magnetic flux leakage, a plate of a magnetic material providing a second magnetic flux transmission means attached to the other end of said housing to provide a magnetic flux path for said magnets and prevent magnetic flux leakage, and pickup head carriage means extending through said central opening and attached to said bobbin for linear movement with said bobbin and at least partially retractable within said housing through said central opening.

Claim 5

A linear actuator as defined by claim 2 and further including guide means integral with said annular ring and extending through said bobbin and providing magnetic flux paths through said bobbin between said ring and said plate.

Claim 6

A linear actuator as defined by claim 3 wherein said guide means comprises a plurality of fingers and said bobbin includes a plurality of passages for mating with said fingers.

Claim 7

A linear actuator as defined by claim 4 wherein said fingers are affixed to said annular ring and extend into said housing in spaced alignment with said magnets and form part of the magnetic flux path.

Claim 8

A compact sealed disc drive comprising an enclosure including a bottom support portion, a motor and spindle mounted in the surface of said bottom support portion, a magnetic disc within said enclosure mounted on said spindle and driven by said motor, magnetic heads for reading and recording data on said disc, a linearly driven carriage for supporting said head and moving said heads relative to the surface of said disc, and a linear actuator mounted in the periphery of said enclosure in close proximity to said disc for moving said carriage, said linear actuator including a generally cylindrical housing of a magnetic material including a plurality of magnets mounted to the inside surface of said housing, a generally cylindrical bobbin including a coil wound on the periphery of said bobbin and a plurality of slots extending therethrough, said bobbin being positioned within said housing and linearly moveable therein with said coil in close proximity to said plurality of magnets, guide means extending through said slots and providing magnetic paths through said bobbin, first magnetic flux transmission means including an annular ring of a magnetic material having a central opening attached to one end of said housing in a peripheral portion of said housing to provide a magnetic path for said magnets and prevent magnetic flux leakage, and second magnetic flux transmission means attached to the other end of said housing to provide a magnetic flux path for said magnet and prevent magnetic flux leakage, said carriage being attached to said bobbin for linear movement with said bobbin.

Claim 9

A compact sealed disc drive comprising an enclosure including a bottom support portion, a motor and spindle mounted in the surface of said bottom support portion, a magnetic disc within said enclosure mounted on said spindle and driven by said motor, magnetic heads for reading and recording data on said disc, a linearly driven carriage for supporting said head and moving said heads relative to the surface of said disc, and a linear actuator mounted in the periphery of said enclosure in close proximity to said disc for moving said carriage, said linear actuator including a generally cylindrical housing of a magnetic material including a plurality of magnets mounted to the inside surface of said housing, a generally cylindrical bobbin including a coil wound on the periphery of said bobbin and a plurality of slots extending therethrough, said bobbin being positioned within said housing and linearly moveable therein with said coil in close proximity to said plurality of magnets, guide means extending through said slots and providing magnetic paths through said bobbin, first magnetic flux transmission means including an annular ring of a magnetic material having a central opening attached to one end of said housing in a peripheral portion of said housing to provide a magnetic path for said magnets and prevent magnetic flux leakage, and second magnetic flux transmission means attached to the other end of said housing to provide a magnetic flux path for said magnet and prevent magnetic flux leakage, said carriage being attached to said bobbin for linear movement with said bobbin.

Claim 10

A compact sealed disc drive as defined by claim 6 wherein said guide means are fixed to said annular ring and extend into said housing in spaced alignment with said magnets.

Claim 11

A compact sealed disc drive as defined by claim 6 wherein said sealed disc drive measures approximately 4.62 inches high, 8.55 inches wide, and 14.25 inches long.

Claim 12

A compact sealed disc drive as defined by claim 6 wherein said carriage is at least partially retractable within said housing through said central opening.