# US 4,398,345 A · Method of making a multitrack magnetic head employing double helix structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,398,345 A - Document ID: US4398345A - Status: Granted - Kind: A - Application number: 06/269,911 - Filed: 1981-06-02 - Granted: 1983-08-16 - Earliest claimed: 1979-10-09 - Assignees: Eastman Kodak Company - Inventors: William W. French; James U. Lemke; Richard J. McClure - Web page: https://patentgrep.com/patent/US4398345A ## CPC - G11B 5/29: Structure or manufacture of unitary devices formed of plural heads for more than one track {(G11B5/33, G11B5/49 and subgroups take precedence; in thin film structure G11B5/31)} - Y10T 29/49048: Machining magnetic material [e.g., grinding, etching, polishing] - Y10T 29/49055: with bond/laminating preformed parts, at least two magnetic - Y10T 29/4906: Providing winding - Y10T 29/49071: by winding or coiling - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A multitrack magnetic head is made from an electrically conductive first helix formed on an iron wire that is, in turn, wound to form a second helix. By longitudinally cutting along one side of the second helix, the first helix is severed into respective coils on discrete gapped cores. ## Claims ### Claim 1 A method for use in the making of a multitrack magnetic head, said method comprising the steps of: (a) longitudinally cutting one side of a double helix core-and-coil structure formed of a substantially helical coil of electrically conductive wire wound on and about a helix of magnetic material, thereby to form a row of discrete coil-wound gapped cores, (b) supporting said row of cores in a jig, and (c) removing parts of said jig to form first and second rows of electrical contacts for the coils on said cores, whereby electrical leads may be brought to said contacts to activate electrically said coils. ### Claim 2 (depends on 1) The method of claim 1 including the additional step of longitudinally shifting respective parts of said cores to remove the respective substantially helical twists thereof. ### Claim 3 (depends on 1) The method of claim 1 including the additional step of placing a pole tip piece, comprised of magnetic material sandwiching a high reluctance material, between the gaps of said coil-wound cores. ### Claim 4 A process for use in making a multitrack magnetic head comprising the steps of: (a) winding an electrical wire substantially helically along and about a length of magnetic material, (b) forming said length of magnetic material with said electrical wire thereon into a substantially helical form thereof, and (c) cutting one side of said helical form of magnetic material so as to sever the helically wound electrical wire into discrete coils on discrete helically twisted sections of magnetic material, said discrete sections of magnetic material constituting the individual cores of said multitrack magnetic head. ### Claim 5 (depends on 4) The process of claim 4 including the additional step of removing the helical twists of the cores formed from said cut magnetic material. ### Claim 6 (depends on 4) The process of claim 4 including the additional step of placing a pole tip piece, comprised of a pair of magnetic structures sandwiching a high reluctance material, within the cut which is made to one side of said helix of magnetic material. ### Claim 7 A method of forming cores for use in magnetic heads comprising the step of cutting a coiled length of magnetic material along one side thereof, said magnetic material having an electrical wire wrapped generally along its length, thereby to sever the magnetic material into a plurality of discrete cores having respective coils thereon. ### Claim 8 A method for use in forming a multitrack magnetic head comprising: (a) substantially helically winding electrical wire along a length of magnetic wire, (b) substantially helically winding the magnetic wire having the electrical wire thereon on an elongated mandrel, (c) placing the wire-supporting mandrel in a jig, and (d) cutting, in the direction of the longitudinal axis of said mandrel, the length of said magnetic wire while said wire is on said mandrel to sever the magnetic and electrical wire into a plurality of discrete coil-wound cores. ### Claim 9 (depends on 8) The method of claim 8 including the additional step of removing said mandrel after said length of magnetic wire is cut. ### Claim 10 (depends on 9) The method of claim 9 including the additional step of applying gap space material to the severed cross-sections of the coil wound cores after said mandrel has been removed. ### Claim 11 (depends on 8) The method of claim 8 wherein said jig is such that, when said length of magnetic wire is cut, said jig is halved, and whereby said jig halves may be oriented for additional processing of the cores which are formed. ### Claim 12 (depends on 11) The method of claim 11 including the additional step of relatively shifting the jig halves to remove substantially the helical twists in said cores. ### Claim 13 (depends on 8) The process of claim 8 including the additional step of lapping said jig to expose respective parts of the coils on said discrete cores.