US2213936A - Electrodynamic pickup - Google Patents

Electrodynamic pickup Download PDF

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Publication number
US2213936A
US2213936A US250729A US25072939A US2213936A US 2213936 A US2213936 A US 2213936A US 250729 A US250729 A US 250729A US 25072939 A US25072939 A US 25072939A US 2213936 A US2213936 A US 2213936A
Authority
US
United States
Prior art keywords
pickup
needle
frame
coil
electrodynamic
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
US250729A
Other languages
English (en)
Inventor
Thompson Lincoln
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.)
SOUND SCRIBER Corp
Original Assignee
SOUND SCRIBER 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 to BE473416D priority Critical patent/BE473416A/xx
Application filed by SOUND SCRIBER CORP filed Critical SOUND SCRIBER CORP
Priority to US250729A priority patent/US2213936A/en
Application granted granted Critical
Publication of US2213936A publication Critical patent/US2213936A/en
Priority to GB11847/47A priority patent/GB626782A/en
Priority to FR946860D priority patent/FR946860A/fr
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
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/12—Gramophone pick-ups using a stylus; Recorders using a stylus

Definitions

  • This invention relates to phonographs
  • the needle holder carries a moving coil for actuating a loudspeaker.
  • One advantage of this construction is that no spring or other restoring member is required to maintain the needle holder between the magnetic poles, as is the case with electromagnetic pickups. Consequently, it is possible to provide a non-magnetic pickup of light metal, ,such as duralumin, being mounted so as to have only a minimum of stiffness, and requiring a relatively small amount of work to oscillate the needleholding structure. The weight applied to the needle to maintain it in the record groove without jumping may thus be diminished and this in turn greatly reduces the wear upon the sound grooves in the record. By means of the present improved pickup, it is possible to reproduce the recorded sounds with the utmost fidelity, using a needle pressure as low as to of an ounce, as compared with the customary needle pressures which are of the order of 2 ounces or more.
  • One object of this invention is to provide an improved pickup for use on disc records and the like, which will be inexpensive to manufacture, simple in construction, compact, ornamental in appearance, low in inertia, and very efficient and durable in use.
  • Fig. 1 is a schematic view showing the improved dynamic pickup as it appears during use.
  • Fig. 2 is a front view of the dynamic pickup per se.
  • Fig. 3 is a rear view of the same.
  • Fig. 4 is a bottom end view of the same.
  • Fig. 5 is an enlarged sectional view of the same, the section being taken on the line 55 of Fig. 2.
  • Fig. 6 is an enlarged fragmentary sectional view of the pickup, taken on the line B6 of Fig. 4.
  • Fig. 7 is a sectional view of on the line 1-1 of Fig. 5.
  • Fig. 8 is an enlarged perspective view of the vibratory needle and coil holding member-the coil being removed to show the interior construction.
  • the numeral l0 denotes a casing in which the reproducer or pickup unit of this invention is mounted.
  • the casing I0 is pivotally secured to and is carried by a reproducer arm I! pivoted on a vertical stud shaft l2, and said arm H is adapted to swing over a disc record l3 seated on a rotatable turntable- M which, is driven in any conventional manner, as by an electrical motor 10 it.
  • the reproducer coil 52 is connected by a pair of conductors I 6 and it to the input terminals l8 and I9 of a vacuum-tube amplifier of conventional form, and which is connected through a switch plug 2
  • the output terminals 23 and 24 of the amplifier 20 are connected by a pair of conductors 25 and 26 to a loudspeaker 21 of conventional form.
  • the motor I5 is connected to the power lines 22 by a pair of conductors 28 and 29the circuit being controlled by a manually operated switch 3t.
  • the reproducer or pickup unit of this in vention includes a central permanently magnetized iron block 3
  • the bottom arms 36 and 31 of the pole pieces 32 and 33 are directed toward each other, and their adjacent ends 38 and 39 are spaced apart to form an air gap 40 in the magnetic circuit.
  • the vibratory pickup needle 48 is detachably secured rigidly to a narrow rectangular frame member, preferably of light non-magnetic material, such as duralumin.
  • the frame member comprises a pair of spaced-apart side members 43 and 44 and an integral offset end block 45.
  • the block 45 has a hollow vertical stem 46 passing therethrough and preferably lying at right-angles to the plane of said frame. Provision is also made of a hollow interiorly threaded horizontal side stem. 41 extending at right-angles to the stem 46.
  • the horizontal side stem 41 is adapted to receive a headed needle-clamping screw 49.
  • the rear end of the frame member is connected to an offset black 50 which has a short, thin, horizontal tongue 5
  • a small hollow coil of insulated wire 52 is seated upon and rigidly connected to the side members '43 and 44 of the frame member between the offset blocks 45 and 50 thereof.
  • the interior bore-53 of the coil 52 is made slightly larger than the thin core member 4i, so that the needle 48 and its carrying frame will be permitted to move freely back and forth without contacting said core member when the needle 48 is oscillated by the lateral undulations of the sound groove in the disc record l3.
  • the vibratory needle holding frame may be said to have a floating bearing in the air gap 40 of the magnetic circuit.
  • a counter balance weight 6i may be provided for the pickup head, said counter-balance extending rearwardly beyond the pivot point 62 on the reproducer arm ii. This permits the pressure of the needle 48 upon the disc record i3 to be maintained at a very low amount; 1. e., in the order of to ounces (5 to 15 grams).
  • a further advantage of the present invention is that the reproducer needle, due to its light weight mounting, may be back-stepped transversely across the sound grooves without lifting the reproducer arm from the record and without in any way injuring or mutilating said grooves.
  • a U-shaped magnet having spaced opposed pole pieces, a loop shaped frame mounted for free oscillation. between saidpoie pieces, said 5 frame carrying a small electrodynamic conductor coil of. similar loop shape, a soft iron core member located within said frame and coil and out of contact therewith, and means to yieldingly cushion said coil holding frame to permit free vibration thereof.
  • a U-shaped magnet having spaced opposed pole pieces, a non-magnetic loop shaped frame mounted for free oscillation between said pole pieces, said frame carrying a small electrodynamic conductor coil of similar loop shape, a soft iron core member located within said'frame and coil and out of contact therewith, and means to yieldingly cushion said coil holding frame to permit free vibration thereof.
  • a permanent magnet having a pair of opposed spaced pole pieces, a fixed soft iron central core located between said pole pieces, a light weight vibratory loop-shaped frame pivotally and yieldably mounted between said pole pieces and freely surrounding said core, a loop-shaped loud-speaker-actuating coil of conductor wire secured to said frame for vibration therewith, said frame carrying a pickup needle extending downwardly substantially at right-angles to the plane thereof.
  • a permanent magnet having a pair of opposed spaced pole pieces, a fixed soft iron central core located between said pole pieces and spaced therefrom by a surrounding air gap, a light weight nonmagnetic vibratory member pivotally and yieldably mounted in said air gap between said pole pieces and located in close proximity. to said core without contact therewith, an electrodynamic coil of conductor wire surrounding said core and secured to said member for vibration therewith, said member carrying a pickup needle extending downwardly therefrom.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Reciprocating, Oscillating Or Vibrating Motors (AREA)
  • Moving Of Heads (AREA)
US250729A 1939-01-13 1939-01-13 Electrodynamic pickup Expired - Lifetime US2213936A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE473416D BE473416A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1939-01-13
US250729A US2213936A (en) 1939-01-13 1939-01-13 Electrodynamic pickup
GB11847/47A GB626782A (en) 1939-01-13 1947-05-02 Improvements in or relating to phonograph pickups
FR946860D FR946860A (fr) 1939-01-13 1947-05-16 Perfectionnements aux liseurs (pick-ups) de phonographes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US250729A US2213936A (en) 1939-01-13 1939-01-13 Electrodynamic pickup

Publications (1)

Publication Number Publication Date
US2213936A true US2213936A (en) 1940-09-03

Family

ID=22948908

Family Applications (1)

Application Number Title Priority Date Filing Date
US250729A Expired - Lifetime US2213936A (en) 1939-01-13 1939-01-13 Electrodynamic pickup

Country Status (4)

Country Link
US (1) US2213936A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BE (1) BE473416A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR946860A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB626782A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416082A (en) * 1944-08-08 1947-02-18 Soundscriber Corp Humless electrodynamic pickup
US2514379A (en) * 1947-08-25 1950-07-11 Jr Charles R Douglass Electrodynamic recording head
US2534725A (en) * 1948-07-15 1950-12-19 Stewart M Miller Electrodynamic pickup hearing u-shaped coil holder
US2542457A (en) * 1946-12-31 1951-02-20 Soundscriber Corp Electrodynamic pickup

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2416082A (en) * 1944-08-08 1947-02-18 Soundscriber Corp Humless electrodynamic pickup
US2542457A (en) * 1946-12-31 1951-02-20 Soundscriber Corp Electrodynamic pickup
US2514379A (en) * 1947-08-25 1950-07-11 Jr Charles R Douglass Electrodynamic recording head
US2534725A (en) * 1948-07-15 1950-12-19 Stewart M Miller Electrodynamic pickup hearing u-shaped coil holder

Also Published As

Publication number Publication date
GB626782A (en) 1949-07-21
FR946860A (fr) 1949-06-16
BE473416A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

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