Electromagnetic print hammer coil assembly
AssigneeInternational Business Machines Corporation
InventorsHo C. Lee, David H. Rickenbach, Gerhard A. Wolfert, Jack L. Zable
Life of this patent
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Abstract
A heat exchange system for an electromagnetically operated print hammer of a print hammer bank provides internal and external heat transfer for the operating windings. A non-magnetic metal bobbin of the heat exchange system provides conductive transfer of heat from the interior of the operating winding to the magnetic core. Flat parallel plates of magnetic material are attached to the sides of the operating winding for external heat transfer and magnetic flux shielding. The plates may have multiple laminations having different saturation and permeability characteristics.
Claims17
A print hammer comprising a hammer element having a magnetic armature,
- a magnetic core forming a magnetic circuit with said armature including a leg forming an operating air gap with said magnetic armature,
- an operating winding assembly including an electrical energizable coil on said leg extending beyond the end of said leg and enclosing said operating air gap, and
- a heat exchange system for said coil comprising
- a heat sink member in a conductive heat transfer relationship with said magnetic core and the surrounding air mass,
- internal heat conductive means thermally coupled in a conductive heat transfer relationship with the inner surface of said coil and said leg of said core,
- external heat conductive means comprising
- a moldable mass of heat conductive material enclosing said coil,
- a magnetic shield structure comprising parallel magnetic plates,
- said magnetic plates having attachment openings occupied by said moldable mass for bonding said magnetic plates to said coil so as to be thermally coupled in a conductive heat transfer relationship with the exterior surface of said coil,
- said magnetic plates having portions extending beyond said winding and forming a shield against stray magnetic field flux in the vicinity of said operating winding,
- said portions of said magnetic plates forming a radiating fin structure for radiating heat to a surrounding air mass.
A print hammer comprising
- a hammer element having a magnetic armature,
- a magnetic core forming a magnetic circuit with said armature including a leg forming an operating air gap with said magnetic armature,
- an operating winding assembly including an electrical energizable coil on said leg extending beyond the end of said leg and enclosing said operating air gap, and
- a heat exchange system for said coil comprising a heat sink member in a conductive heat transfer relationship with said magnetic core and the surrounding air mass,
- internal heat conductive means thermally coupled in a conductive heat transfer relationship with the inner surface of said coil and said leg of said core, and
- external heat conductive means comprising a magnetic shield structure thermally coupled in a conductive heat transfer relation with the exterior surface of said coil and a surrounding air mass,
- said magnetic shield structure comprising magnetic plates having multiple laminated layers of magnetic material, said multiple layers having different magnetic permeabilities and saturation levels,
- said magnetic shield structure providing a magnetic circuit return path for stray flux generated in the vicinity of said coil.
Dependencies are inferred from the claim text.