Rotary positioning apparatus

Rotary positioning apparatus comprising:

• an actuator body having a given mass characteristic first and second longitudinally spaced apart end portions, and a center of gravity;
• a pivot member for rotatably supporting an actuator body at a location between said first and second end portions;
• couple means for applying a torque to said actuator body at a location remote from said pivot member, said torque being applied by the application of torque defining, opposite and spaced apart forces thereto generated by current, i, within a coil of active length, l, and a magnetic field of value, B, under the relationship:
• F=BLi, to effect a predetermined pivotal movement of said actuator body about said pivot member, said couple means being configured as two said coils fixed to and movable with said actuator body first end portion and a fixed permanent magnet assembly positioned to form said magnetic field across said coils.

Rotary positioning apparatus comprising:

• an actuator body having a given mass characteristic, first and second spaced apart end portions, and a center of gravity;
• a pivot member for rotatably supporting said acutator body at a location between said first and second end portions;
• a couple assembly for applying a torque to said actuator body at a location remote from said pivot member, said torque being applied by the application of torque defining, opposite and spaced apart forces thereto generated by current, i, within a coil of active length, 1, and a magnetic field of value, B, under the relationship:
• F=Bli, to effect a predetermined pivotal movement of said actuator body about said pivot member, said couple assembly comprising:
• a first elongate permanent magnet of length between its first and second pole ends selected to derive a torque arm corresponding in dimension with said force spacing, fixed to and movable with said actuator body first end portion;
• second and third permanent magnets mounted upon said first end portion at opposite sides of said first permanent magnet, spaced therefrom and having third and fourth pole ends coextensive therewith, to establish magnetic fields intermediate said first and third pole ends and second and fourth pole ends;
• and
• said coil being fixed in position and including windings of said active length, 1, located intermediate said first and second and first and third permanent magnets.

A rotary actuator for positioning a head at select locations adjacent a surface of a memory disk comprising:

• an arm member of given mass having a first end portion for supporting said head, an oppositely disposed second end portion and a center of gravity location disposed therebetween;
• a pivot member positioned adjacent said disk and rotatably supporting said arm member intermediate said first and second end portions;
• first and second coils mounted upon said arm member second end portion remotely from said pivot member, representing with said head a portion of said mass, spaced apart a distance for deriving opposite, spaced forces forming a torque and energizable to carry current generating electromagnetic fields;
• and
• first and second permanent magnet assemblies, fixed with respect to said coils and located in spaced adjacency therewith for establishing magnetic fields reactive with said electromagnetic fields generated by said first and second current carrying coils to develop said spaced, oppositely directed, forces which sum to derive substantially pure torque at said first and second coils.

A rotary actuator for positioning a head at select locations adjacent a surface of a memory disk comprising:

• an arm member of given mass having a first end portion for supporting said head, an oppositely disposed second end portion and a center of gravity location disposed therebetween;
• a pivot member positioned adjacent said disk and rotatably supporting said arm member intermediate said first and second end portions;
• first and second coils mounted upon said arm member second end portion, representing with said head a portion of said mass, spaced apart a distance for deriving opposite, spaced forces forming a torque and energizable to carry current generating electromagnetic fields;
• first and second permanent magnet assemblies, fixed with respect to said coils and located in spaced adjacency therewith for establishing magnetic fields reactive with said electromagnetic fields generated by said first and second current carrying coils to develop said oppositely directed, torque defining forces at said first and second coils, each said first and second permanent magnet assemblies comprising at least two spaced apart magnet segments of opposite polarity configured to substantially linearize the said defined torque derived at said first and second coils along the locus of pivotal movement of said arm member.

A rotary actuator for positioning a head at select locations adjacent a surface of a memory disk comprising:

• an arm member of given mass having a first end portion for supporting said head, an oppositely disposed second end portion and a center of gravity location disposed therebetween;
• a pivot member positioned adjacent said disk and rotatably supporting said arm member intermediate said first and second end portions;
• first and second coils mounted upon said arm member second end portion, representing with said head a portion of said mass, spaced apart a distance for deriving opposite, spaced forces forming a torque and energizable to carry current generating electromagnetic fields;
• and
• first and second permanent magnet assemblies, fixed with respect to said coils and located in spaced adjacency therewith for establishing magnetic fields reactive with said electromagnetic field generated by said first and second current carrying coils to develop said oppositely directed, torque defining forces at said first and second coils, said first and second permanent magnet assemblies each comprising at least one permanent magnet having regions of predetermined field strength selected to derive a substantially linear relationship of said oppositely directed forces with respect to the rotational position of said arm member.

A rotary actuator for positioning a head at select locations adjacent the surface of a memory disk, comprising:

• an arm member of given mass having a first end portion for supporting said head and an oppositely disposed second end portion spaced therefrom;
• a pivot member positioned adjacent said disk and rotatably supporting said arm member, disposed intermediate said first and second end portions;
• a permanent magnet assembly mounted upon said arm member second end portion, representing with said head a portion of said mass, including a first permanent magnet having a torque moment defining dimension extending along a longitudinal axis between first and second magnet poles to effect pivotal movement of said arm member about said pivot member without applying substantial reaction forces thereon;
• a coil assembly, fixed with respect to said arm member and having windings positioned to intercept magnetic flux emanating from said first permanent magnet for carrying current developing oppositely directed, torque defining forces substantially at said first and second magnet poles.