US2498671A - Sound reproducer or recorder head - Google Patents

Sound reproducer or recorder head Download PDF

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Publication number
US2498671A
US2498671A US639273A US63927346A US2498671A US 2498671 A US2498671 A US 2498671A US 639273 A US639273 A US 639273A US 63927346 A US63927346 A US 63927346A US 2498671 A US2498671 A US 2498671A
Authority
US
United States
Prior art keywords
armature
stylus
recorder head
sound reproducer
pole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US639273A
Other languages
English (en)
Inventor
Gayford Michael Lawrence
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB2087/45A external-priority patent/GB608036A/en
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Application granted granted Critical
Publication of US2498671A publication Critical patent/US2498671A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R11/00—Transducers of moving-armature or moving-core type
    • H04R11/08—Gramophone pick-ups using a stylus; Recorders using a stylus

Definitions

  • invention relates to electricsound re-.
  • Figs. 3 and, 4 show two forms of this element in greater detail.
  • the armature itselfconsists of a single substantially rectangular block l5 of highly.-magnetisable-material.
  • 5 is formed with integral-lugs lfi projecting in line from-the opposite side-edges andslotted ver-' tically so' that each lug can-receive a'spring strip It is known too that in soundrecording and reproducingheads it is highly desirablev to reduce the moment of inertia of the armature as much as possible, and this especiallywhere a wide frequency band is to be dealt with.
  • Oneof the objects of the present invention is to attjainlj this desidefratum of reduced moment of inertia.
  • Theinvention is an improvement in or modificatiion' of 'theinventi'o'h disclosed in the copending U. S patent application Ser.. 1 ⁇ ,lo.619,652, filed October 1', 1945,'now abandoned.”
  • Fig. '1' is a front view of 'an electrical recorder head in accordance with the present invention, certain parts being removed for the sake of clarity.
  • Fig. 2 is a sectional view on the line AA of Fig. 1, and
  • Figs. 3 and 4 are side views, on an enlarged scale, of two forms of armature assembly utilised in the recorder head shown in Figs. 1 and 2.
  • FIGs. 1 and 2 An electrical recorder in accordance with the present invention is shown in Figs. 1 and 2.
  • a U-shaped permanent magnet I has pole-pieces 2 and 3 held magnetically against its bottom extremities and extending inwardly towards one another. These pole-pieces 2 and 3 are bifurcated to form upper limbs '4 and 5 and lower limbs 6 and l. Plates 8 and 9 of brass cover the front and rear sides of the pole-pieces 2 and 3, extending across the ends of the gap between them and being secured by screws l0 passing into tapped holes I in the pole-pieces 2 and 3. In Figure 1 the front plate 8 has been omitted for clarity. Within the gap between the pole-pieces s arranged an armature
  • coll I4 is located in the horizontal space beween the upper and lower limbs 4, 5, 6, I of the ole-pieces 2 and 3 so as to surround the armaure I2. It is in the construction and mounting f this armature l2 that the present invention I1 ofnon-magnetic material which is riveted or spot-welded in position as indicated at l8.
  • Figs. 3 and 4 difier from one another in the arrangement by which the stylus I3 is clamped in position.
  • slopes towards the shank of the stylus and makes direct contact with it.
  • lies parallel with the stylus.
  • This screw in Fig. 4 has a tapered head which engages in an oval tapered recess in the armature. The long axis of the oval is at right angles to the plane of the armature.
  • Two slots 22 and 23 ending in two holes 24 and 25 are cut right through the armature to form a tongue 26 which is forced over by the screwing in of the taper-headedg screw 2
  • a stylus with a longer shank is used and it goes into a hole which extends vertically through the entire height of the armatur
  • the actual clamping point is at the bottom ed of the armature and hence as near to the actual cutting point as possible.
  • the hole in the armature is preferably given, a slight reduction in diameter towards its top
  • backctot-Fig. ;2 --it Will-be seenthat the brass end and the stylus shank given a similar taper.
  • the stylus is pushed up into the hole as far as it will go and is thus held tightly at its to end. It is then clamped at the bottom end by screwing in the adjacent screw in the armature.
  • the stylus shank held tightly at both the top and bottom of the armature plate, hence avoiding any flost motion or rocking of the stylus shank about the point of clamping.
  • the stylus is also gripped so as to give a minimum distance, and hence minimum flexibility, between the lower clamping point and the cutting point. This is desirable, as one of the factors fixing the upper cut-off frequency. of then recorded frequency response is the inevitable slight flexibility of the stylus between its clamping point and the cutting point. In this case the distance between these two points is reduced.
  • the thickness of the block 15 is reduced in those parts remote from the stylus and screw sockets.
  • this variation in thickness of the block it may be necessary to vary the width of the air gap as between the upper pole-piece limbs 4 and 5 and the lower limbs 6 and 'I: thus it will be seen in Fig. 1 that the limbs 4 and 5 are slightly longer than the limbs 6 and I.
  • the armature is not cut down at the top. This could be done if the stylus shank and tapered screw were reduced in length.
  • the stylus were of sapphire, which will last indefinitely, it would be permanently in position, so that there would be no need for the provision of clamping screw 2
  • the pole-pieces and armatures of the instrument are of an alloy, of high magnetic permeability which will provide the maximum flux combined with low alternating reluctance and low eddy and hysteresis losses.
  • the permanent magnet is of an alloy, in which the magnetic properties have been enhanced by heat. treatment in a magnetic field.
  • the spring strips 11 are of a material, such as beryllium-copper,
  • a translating device comprising a support, electromagnetic means surrounding said support, a pair of resilient members of non-magnetic material spaced from each other, means for attaching the extremities of said members to said support, an armature of magnetisable material secured to said members by a pair of integral lugs at points displaced from the points of attachment of said members both' longitudinally and laterally thereof, and means for causing said electromagnetic means and portions of said members to vibrate.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Impact Printers (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
US639273A 1945-01-26 1946-01-05 Sound reproducer or recorder head Expired - Lifetime US2498671A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2087/45A GB608036A (en) 1944-11-09 1945-01-26 Improvements in or relating to sound reproducer or recorder heads

Publications (1)

Publication Number Publication Date
US2498671A true US2498671A (en) 1950-02-28

Family

ID=9733353

Family Applications (1)

Application Number Title Priority Date Filing Date
US639273A Expired - Lifetime US2498671A (en) 1945-01-26 1946-01-05 Sound reproducer or recorder head

Country Status (4)

Country Link
US (1) US2498671A (fr)
BE (1) BE480688A (fr)
ES (1) ES178082A2 (fr)
FR (1) FR931028A (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB188029A (en) * 1921-07-23 1922-10-23 Thomas Henry Cole Improvements in gramophones and the like
US1968149A (en) * 1931-08-17 1934-07-31 Capehart Corp Phonograph pick-up mechanism
US2016622A (en) * 1930-09-12 1935-10-08 Columbia Graphophone Co Ltd Moving coil electromechanical device
US2037255A (en) * 1931-03-21 1936-04-14 United Res Corp Electromagnetic translating device
US2108275A (en) * 1934-05-17 1938-02-15 Philips Nv Electromagnetic device and method of making same
US2141584A (en) * 1936-02-22 1938-12-27 Wittander Samuel Sound reproducing and recording apparatus
US2412718A (en) * 1943-08-07 1946-12-17 Webster Electric Co Inc Recorder

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB188029A (en) * 1921-07-23 1922-10-23 Thomas Henry Cole Improvements in gramophones and the like
US2016622A (en) * 1930-09-12 1935-10-08 Columbia Graphophone Co Ltd Moving coil electromechanical device
US2037255A (en) * 1931-03-21 1936-04-14 United Res Corp Electromagnetic translating device
US1968149A (en) * 1931-08-17 1934-07-31 Capehart Corp Phonograph pick-up mechanism
US2108275A (en) * 1934-05-17 1938-02-15 Philips Nv Electromagnetic device and method of making same
US2141584A (en) * 1936-02-22 1938-12-27 Wittander Samuel Sound reproducing and recording apparatus
US2412718A (en) * 1943-08-07 1946-12-17 Webster Electric Co Inc Recorder

Also Published As

Publication number Publication date
ES178082A2 (es) 1947-07-01
FR931028A (fr) 1948-02-11
BE480688A (fr)

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