Method of making compact electric coils
OwnerMogens Hvassinventor
Life of this patent
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Abstract
A method of producing a compact electric coil such as a voice coil for loudspeakers, whereby a coil member is wound of ordinary round wire having a coating of a thermoplastic or thermosetting bonding material, whereafter the coil member mounted on a mandrel is heated together with the mandrel and thereafter cooled from its outside so as to crimp around the mandrel while this is still warm and expanded. Hereby the round wire will be forced inwardly with high force so as to get cross sectionally deformed to fill out the available space to a very large degree, and the bonding material sets so as to hold the coil in its compacted shape whereby a coil of high rigidity and heat conductivity is produced. The coil is easily retractable from the mandrel upon further cooling of the latter.
Claims8
A method of producing compact electric coils having a high space factor, such as voice coils for loudspeakers, whereby the coil is wound in winding layers of insulated wire of round cross sectional shape, characterized in that the method comprises the steps of arranging a coil on a mandrel filling out the coil, subjecting the mandrel and coil to a differential thermal treatment to cause, without a counter pressure being exerted on the wire, a radial compression of the wire until the wire in each winding layer becomes deformed at surface portions thereof so as to be pressed substantially flat against the surfaces of the adjoining wire portions of the adjacent winding layers.
A method of compacting an electric coil to increase the space factor thereof, the coil being comprised of a plurality of turns of round cross-sectional wires arranged in layers, the method comprising the steps of:
- arranging a coil on a mandrel filling out the coil, subjecting the mandrel and coil to a differential thermal treatment to effectively cause the coil windings to be tightened about the mandrel to such a degree that the resulting radial forces on the wire of the coil are sufficient to effect a cross-sectional deformation of the wire in each of the turns against adjacent turns and therewith compaction of the windings.
Dependencies are inferred from the claim text.