Thin and compact micro-Winchester head and disk assembly

A compact, sealed head and disk assembly for a rotating non-removable disk data storage subsystem comprising:

• a flat and thin rigid generally rectangular box housing for aligning, mounting and substantially enclosing the elements providing said head and disk assembly without protrusions extending therefrom;
• a thin spindle motor mounted in a well formed in a floor of said housing and having a spindle rotatable at a predetermined angular velocity;
• at least one magnetic media data storage disk in said housing and mounted directly to said spindle for rotation;
• a limited angular displacement rotary actuator subassembly journalled to a post extending from the floor in said housing adjacent to the magnetic media data storage disk and including:
• a rotary actuator motor located oppositely away from the data storage disk and comprising:
• a coil,
• a first flux return plate mounted to said housing,
• a first permanently magnetized flux-providing flat plate magnet mounted adjacent to and within the locus of movement of said coil, said first magnet having a plurality of magnetic pole regions at a major surface thereof facing said coil, said first magnet being mounted to said first flux return plate so that said plate returns the flux between pole regions of said first magnet at a surface facing said first plate,
• a second flux return plate mounted to said housing in alignment with and spaced away from said first flux return plate and first magnet,
• a second permanently magnetized flux-providing flat plate magnet mounted adjacent to and within the locus of movement of said coil, and having a major surface facing the major surface of said first magnet across a gap slightly greater than the thickness of said coil and having a plurality of magnetic pole regions on said major surface complementary with the oppositely facing poles of said first magnet,
• said coil being freely moveable along its locus of limited displacement in said gap and having windings disposed to cut the flux of said regions,
• whereby said first and second magnets provide a magnetic flux field in said gap the lines of which are cut by the coil and said flux return plates contain said flux to the vicinity of said gap and prevent said flux from reaching said data storage disk;
• and,
• a unitary planar frame journalled to the post fixed in said housing and rotatable in alignment with the plane of said data storage disk, said frame comprising:
• a hub for containing a plurality of bearing means for providing a rotatable journal with said post,
• a first region extending from the hub oppositely away from the data storage disk for supporting said coil of said rotary actuator motor,
• a second region extending from the hub for supporting a data transducer arm carrying a data read and write transducer in close proximity to concentric data tracks formed on said disk surface, there being a single transducer for each data surface of said data storage disk, and
• a third region carrying a counterweight for countering any imbalances presented by the presence of said first and second regions, thereby presenting a constant torque load to said rotary actuator motor irrespective of orientation of said head and disk assembly, the counterweight disposed in part in vertical interlaid arrangement with respect to said data storage disk;
• and
• a cover for closing and sealing said housing.