US2809237A - Magnetic sound recording head - Google Patents

Magnetic sound recording head Download PDF

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Publication number
US2809237A
US2809237A US209250A US20925051A US2809237A US 2809237 A US2809237 A US 2809237A US 209250 A US209250 A US 209250A US 20925051 A US20925051 A US 20925051A US 2809237 A US2809237 A US 2809237A
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Prior art keywords
magnetic
sound recording
recording head
magnetic sound
core
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Expired - Lifetime
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US209250A
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Bergmann Friedrich
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BASF SE
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BASF SE
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    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127Structure or manufacture of heads, e.g. inductive
    • G11B5/133Structure or manufacture of heads, e.g. inductive with cores composed of particles, e.g. with dust cores, with ferrite cores with cores composed of isolated magnetic particles
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127Structure or manufacture of heads, e.g. inductive

Definitions

  • the magnetic sound recording head hitherto used insound recording and sound reproduction consists of a magnetic core and a wire coiling around the said core.
  • the electric oscillations flowing through the said wire coiling generate an alternating magnetic field in the vicinity of a slit provided in the magnetic core and this field imprints itself upon the permanently magnetisable sound carrier on being led past the said slit.
  • magnetic cores of highly permeable material as for example iron-nickel or iron-nickle-copper alloys which are known to have a very high initial permeability.
  • the core is made up of sheets which are insulated against each other from electricity.
  • the magnetic sound recording heads are markedly dependent as to their magnetic field from the frequency, in particular are the high frequencies notably affected, since the eddies in the magnetic core increase in proportion to the square of the frequency.
  • ferrites contemplated for use within the purview of my invention are nickel ferrite, nickel-zinc ferrite, manganese ferrite and manganese-zinc ferrite. These substances not only have high initial permeability but also a very low electric conductivity. They can be used in a compact from as a material for making magnetic cores, without eddy losses occurring and, as a result, the magnetic field being brought into dependency from the frequency at the slit provided in the magnet.
  • the magnet cores may be made by preparing a mixture of 9.4 percent of nickel oxide, 23.8 percent of zinc oxide and 66.8 percent of ferric oxide, either by intimately mixing the said oxides or by precipitating them jointly from their respective metal salt solutions, pressing the mixture into suitably shaped molds, annealing the resulting shaped body at a temperature of between about 1200 and 1300 C. in an atmosphere of oxygen and allowing it to cool down very slowly in this atmosphere.
  • More ease and conveniency in the manufacture of the cores will be afforded by giving the cores, instead of the standard circular form, a square-bar form in crosssection, because the ferrites may be more easily pressed and annealed in this shape. In practical use, three such bars are arranged to form a triangle with a slit being left at one of the intersectional points of the bars.
  • the ends of the bars and the sliding surface for the recorder band may be suitably shaped by abrasion.
  • 1 represents the squarebars made of ferrite
  • 2 represents the slit
  • 3 represents the wire coiling
  • 4 represents the recorder band.
  • Magnetic sound recording head having a core consisting exclusively of magnetic ferrite.
  • Magnetic sound recording head having a core consisting exclusively'of manganese ferrite.
  • Magnetic sound recording head having a core consisting exclusively of nickel-zinc ferrite.
  • Magnetic sound recording head having a core consisting exclusively of manganese-zinc ferrite.
  • Magnetic sound recording head having a core consisting of three bars made exclusively from ferrite and arranged to form a triangle with a slit being left at one of the intersection points of the bars.
  • a magnetic sound recording head comprising a magnetic core having legs separated by a slit, said core including the portions thereof adjacent said slit consisting solely of magnetic ferrite.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Magnetic Heads (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)

Description

Oct '8, 95 F. BERGMANN 2,809,237
MAGNETIC SOUND RECORDING HEAD Filed Feb. 5, 1951 INVENTOR: FRIEDRICH BERGMANN ATT'YS United States Patent Ofiicc 2,809,237 Patented st. 8, 1957 7 2,809,237 MAGNETIC some RECGRDING rman Friedrich Bergmann, Ludwigshafen (Rhine), Germany,
assignor to Badische Aniiin- & Soda-Fahrih Aktiengeselischaft, Ludwigshafen (Rhine), Germany Application February 3, 1951, Serial No. 299,258] Claims priority, application Germany February 6, 1950 6 Claims. (Cl. 179-1062) This invention relates to means for the magnetographic recording of sound.
The magnetic sound recording head hitherto used insound recording and sound reproduction consists of a magnetic core and a wire coiling around the said core. The electric oscillations flowing through the said wire coiling generate an alternating magnetic field in the vicinity of a slit provided in the magnetic core and this field imprints itself upon the permanently magnetisable sound carrier on being led past the said slit. To secure the highest possible efliciency magnetic sound recording heads are fitted with magnetic cores of highly permeable material, as for example iron-nickel or iron-nickle-copper alloys which are known to have a very high initial permeability. To cut down the eddy losses in the magnetic core during operation, the core is made up of sheets which are insulated against each other from electricity.
By reason of the high conductivity of the metallic materials hitherto used for making the core, the magnetic sound recording heads are markedly dependent as to their magnetic field from the frequency, in particular are the high frequencies notably affected, since the eddies in the magnetic core increase in proportion to the square of the frequency.
I have now found that the disadvantages hitherto inherent in magnetic sound recording heads can be substantially obviated by using magnetic ferrite, instead of the materials listed above, for making the cores of magnetic sound recording heads. Examples of ferrites contemplated for use within the purview of my invention are nickel ferrite, nickel-zinc ferrite, manganese ferrite and manganese-zinc ferrite. These substances not only have high initial permeability but also a very low electric conductivity. They can be used in a compact from as a material for making magnetic cores, without eddy losses occurring and, as a result, the magnetic field being brought into dependency from the frequency at the slit provided in the magnet.
According to a preferred embodiment of my invention the magnet cores may be made by preparing a mixture of 9.4 percent of nickel oxide, 23.8 percent of zinc oxide and 66.8 percent of ferric oxide, either by intimately mixing the said oxides or by precipitating them jointly from their respective metal salt solutions, pressing the mixture into suitably shaped molds, annealing the resulting shaped body at a temperature of between about 1200 and 1300 C. in an atmosphere of oxygen and allowing it to cool down very slowly in this atmosphere. More ease and conveniency in the manufacture of the cores will be afforded by giving the cores, instead of the standard circular form, a square-bar form in crosssection, because the ferrites may be more easily pressed and annealed in this shape. In practical use, three such bars are arranged to form a triangle with a slit being left at one of the intersectional points of the bars. The ends of the bars and the sliding surface for the recorder band may be suitably shaped by abrasion.
One embodiment of my invention is illustrated in the accompanying drawing in which 1 represents the squarebars made of ferrite, 2 represents the slit, 3 represents the wire coiling and 4 represents the recorder band.
What I claim is:
1. Magnetic sound recording head having a core consisting exclusively of magnetic ferrite.
2. Magnetic sound recording head having a core consisting exclusively'of manganese ferrite.
3. Magnetic sound recording head having a core consisting exclusively of nickel-zinc ferrite.
4. Magnetic sound recording head having a core consisting exclusively of manganese-zinc ferrite.
5. Magnetic sound recording head having a core consisting of three bars made exclusively from ferrite and arranged to form a triangle with a slit being left at one of the intersection points of the bars.
6. A magnetic sound recording head comprising a magnetic core having legs separated by a slit, said core including the portions thereof adjacent said slit consisting solely of magnetic ferrite.
References Cited in the file of this patent UNITED STATES PATENTS 2,452,529 Snoek Oct. 26, 1948 2,452,530 Snoek Oct. 26, 1948 2,452,531 Snoek Oct. 26, 1948 2,493,742 Begun Jan. 10,1950 2,536,260 Burns Jan. 2, 1951 2,592,652 Buhrendorf Apr. 15, 1952 FOREIGN PATENTS 274,288 Switzerland June 16, 1951

Claims (1)

1. MAGNETIC SOUND RECORDING HEAD HAVING A CORE CONSISTING EXCLUSIVELY OF MAGNETIC FERRITE.
US209250A 1950-02-06 1951-02-03 Magnetic sound recording head Expired - Lifetime US2809237A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE287606X 1950-02-06

Publications (1)

Publication Number Publication Date
US2809237A true US2809237A (en) 1957-10-08

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US209250A Expired - Lifetime US2809237A (en) 1950-02-06 1951-02-03 Magnetic sound recording head

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US (1) US2809237A (en)
CH (1) CH287606A (en)
FR (2) FR1032056A (en)
GB (1) GB717573A (en)
IT (1) IT472736A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2933565A (en) * 1953-04-15 1960-04-19 Siemens Ag Magnetic transducers
US3079470A (en) * 1959-12-21 1963-02-26 Armour Res Found Magnetic transducer head
US3268987A (en) * 1959-05-11 1966-08-30 Adams Edmond Method of making transducer head cores
US4242711A (en) * 1977-04-13 1980-12-30 Nippon Gakki Seizo Kabushiki Kaisha Multilayer magnetic head core

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4188649A (en) * 1977-12-05 1980-02-12 Ibm Corporation Magnetic head having a jagged-edged gap, and method for producing such head

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452529A (en) * 1941-10-24 1948-10-26 Hartford Nat Bank & Trust Co Magnet core
US2452531A (en) * 1943-05-31 1948-10-26 Hartford Nat Bank & Trust Co Process of manufacturing a magnetic material and magnetic core
US2452530A (en) * 1943-05-15 1948-10-26 Hartford Nat Bank & Trust Co Magnetic core
US2493742A (en) * 1945-08-22 1950-01-10 Brush Dev Co Magnetic transducing core for magnetic record transducers
US2536260A (en) * 1948-12-30 1951-01-02 Rca Corp Device for reproducing magnetic records
CH274288A (en) * 1948-11-12 1951-03-31 Alexander Dr Egerer Karl Magnetic sound recording and reproducing head for tape-shaped sound carriers.
US2592652A (en) * 1950-02-18 1952-04-15 Bell Telephone Labor Inc Magnetic transducer head

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452529A (en) * 1941-10-24 1948-10-26 Hartford Nat Bank & Trust Co Magnet core
US2452530A (en) * 1943-05-15 1948-10-26 Hartford Nat Bank & Trust Co Magnetic core
US2452531A (en) * 1943-05-31 1948-10-26 Hartford Nat Bank & Trust Co Process of manufacturing a magnetic material and magnetic core
US2493742A (en) * 1945-08-22 1950-01-10 Brush Dev Co Magnetic transducing core for magnetic record transducers
CH274288A (en) * 1948-11-12 1951-03-31 Alexander Dr Egerer Karl Magnetic sound recording and reproducing head for tape-shaped sound carriers.
US2536260A (en) * 1948-12-30 1951-01-02 Rca Corp Device for reproducing magnetic records
US2592652A (en) * 1950-02-18 1952-04-15 Bell Telephone Labor Inc Magnetic transducer head

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2933565A (en) * 1953-04-15 1960-04-19 Siemens Ag Magnetic transducers
US3268987A (en) * 1959-05-11 1966-08-30 Adams Edmond Method of making transducer head cores
US3079470A (en) * 1959-12-21 1963-02-26 Armour Res Found Magnetic transducer head
US4242711A (en) * 1977-04-13 1980-12-30 Nippon Gakki Seizo Kabushiki Kaisha Multilayer magnetic head core

Also Published As

Publication number Publication date
FR62575E (en) 1955-06-15
IT472736A (en)
CH287606A (en) 1952-12-15
GB717573A (en) 1954-10-27
FR1032056A (en) 1953-06-29

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