US1707544A - Electrodynamic device - Google Patents

Electrodynamic device Download PDF

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Publication number
US1707544A
US1707544A US127152A US12715226A US1707544A US 1707544 A US1707544 A US 1707544A US 127152 A US127152 A US 127152A US 12715226 A US12715226 A US 12715226A US 1707544 A US1707544 A US 1707544A
Authority
US
United States
Prior art keywords
coil
diaphragm
conductor
electrodynamic
secured
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
US127152A
Other languages
English (en)
Inventor
Albert L Thuras
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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 NL23790D priority Critical patent/NL23790C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US127152A priority patent/US1707544A/en
Priority to GB14918/27A priority patent/GB275567A/en
Priority to DEE35798D priority patent/DE527965C/de
Priority to FR636865D priority patent/FR636865A/fr
Application granted granted Critical
Publication of US1707544A publication Critical patent/US1707544A/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
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/06—Loudspeakers
    • 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
    • H04R9/02—Details
    • H04R9/022—Cooling arrangements

Definitions

  • This invention relates to electrodynamic devices and particularly to an acoustic devlce employing an electrodynamically actuated vibrating element.
  • An object of the invention is to increase the operating efficiency of electrodynamic devices.
  • a more specific object is to convert elecinto acoustic energy with high and substantially uniform efliciency over a wide frequency range.
  • the mass of the coil is made approximately equal to the effective massof the diaphragm in order to' obtain a maximum operating efliciency in the vibrating' structure. diaphragm of the mately equal to the tion.
  • Fig. 1 is a sectional view of a loud speaker employing the present invention
  • Fig. 2 is an enlarged view of a portion of the diaphragm and the coil attached thereto;
  • Fig. 3 is a view taken along the line 3-3 of Fig. 1.
  • the diaphragm to which the coil 14 is attached comprises a stiff dish-shaped portion 17,-a flexible corrugated portion 18, and a flat portion 19 which .is clamped between the housing structure 20 and the upper portion 15' of the core structure;-
  • the rate of increase is such as to maintain a constant velocity in the air chambers.
  • the remainder of the sound passage is also preferably designed to progressively increase in area from the diaphragm to the mouth of the horn 26.
  • the space at the mid-portion of the core 10 is closed at each end by a material having a series acoustic resistance such as the fine mesh wire gauze members 27 and 28 and a sound absorbing material 29, such as wool is employed to fill the space between these gauze members.
  • a material having a series acoustic resistance such as the fine mesh wire gauze members 27 and 28 and a sound absorbing material 29, such as wool is employed to fill the space between these gauze members.
  • the process of making the coil 14 consists in coating a clean aluminum ribbon, having a thickness of about .002" and a width of about .014, with a thin solution of a phenolic condensation product dissolved in acetone.
  • the coated ribbon is then subjected to a temperature of about 350 C, for .a short period in order to thoroughly harden the coating.
  • the coated conductor is then passed through a second solution of av phenolic condensation product, preferably slightly more viscous than the previous coating solution, after which it is subjected to a temperature of about 250 C. in order to cause the evaporation of some of the solvent.
  • the coated ribbon is then wound edgewise on a collapsible mandrel to form a coil about 2 in diameter which is baked at a temperature of about 250 C and gradually cooled to room r temperature.
  • the coil now rigid and substantially free from internal strains, is removed from the mandrel and trimmed down to about turns which gives the coil a height of about .105".
  • the inner surface of the coil is coated with a cementing material for example, a phenolic condensation product, or shellac and one edge of astrip 30 of fabric material, such as oiled silk, is secured thereto by means of the cement.
  • the coil is again placed on a mandrel, the diameter of which is less than that of the mandrel previously used by an amount equal to the thickness of the silk, and is heated to about 150 C. in order to thoroughly dry the cement after which the opposite edge of the strip of oiled silk is socured to the diaphragm near the periphery of the stifiened portion 17 and the end portions 35 and 36 of the ribbon conductor are insulated and secured along the troughs of the corrugations of the flexible portion 18 of the diaphragm by means of a coating of shellac-
  • the assembled structure 1s again heated to a temperature of approximately 150 C. after which it is ready to be mounted in the receiver.
  • the coil is positioned midway between the annular pole pieces 12 and 13 which are sepa rated by about .035" and the ends of the rib" bo n conductor are secured to the screws 31 and 32 which are electrically connected to the terminals 33 and 34, respectively. Since the width of the coil and fabric is about .017 there remains a clearance of only about .009" betweeneither pole piece and the coil.
  • Em l-TC Due to the presence of impurities, this value may be slightly increased, but should in no case be above 90.
  • Em l-TC it is necessary to employ a diaphragm the vibrating portion of which is sufliciently large to cause a large volume displacement
  • the flexible portion 18 of the diaphragm preferably consists of substantially straight corrugations extending perpendicular to radii drawn to the inner ends of the corrugations as described in a copending application of H. C. Harrison, Serial No. 102,454, i'iled April 16, 1926.
  • the reactance due to the compliance of this portion of the diaphragm is preferably made about e ual in magnitude to the mass react-ance of: t e air which the diaphragm sets into vibration
  • t e air which the diaphragm sets into vibration
  • V7 hen employing a horn having a sufliciently large mouth opening and a sufficient length, the efficiency of the device is substantially uniform over a frequency range from about 80 cycles to above 5000 cycles. While the invention is of special value in conjunction with an acoustic device as described, a driven means other than a diaphragm may be employed and this feature is to be included within the scope of the present invention.
  • a diaphragm of light material and a light stiffcylin'drical coil consisting of a fiat insulated conductor wound edgewise and connected to said diaphragm for driving it.
  • a diaphragm having a stifi'ened central portion and a flexible portion surrounding said central portion, a
  • magnet a coil of a thin rectangular shaped.
  • An electrodynamic receiver comprising a diaphragm, a casing therefor, 1 a magnet, and a coil consisting of a single helix of a flat insulated conductor wound edgewise and secured to said diaphragm for driving it, said coil being of such dimensions that it substantially fills the available space between the pole pieces of said magnet.
  • a vibrational elementfor an electrodynamic receiver comprising. a diaphragm and a coil, which consists in coating a fiat conductor with a thin layer of insulating material, baking said insulated conductor, coating said conductor with a second thin layer of insulating material, drying the second layer of insulating ma-' terial, winding said insulated conductor edgewise on a collapsible mandrel to form said coil,
  • An electrodynamic acoustic device comprising a diaphragm having a stiffened central portion and a flexible peripheral portion, and a coil attached to the outer edge of the central portion consisting of an edgewisewound rectangular shaped conductor whose convolutions are insulated from each other and held together by an insulating cement.
  • An electrodynamic device comprising a diaphragm composed mainly of aluminum comprising a flexible portion and a plurality of curved surfaces joined together to form a stiff portion'and a coil secured to the stiff portion of said diaphragm for driving it, comprising a ribbon-like conductor mainly of aluminum wound on and cemented to a piece of fabric.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
US127152A 1926-08-04 1926-08-04 Electrodynamic device Expired - Lifetime US1707544A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL23790D NL23790C (ja) 1926-08-04
US127152A US1707544A (en) 1926-08-04 1926-08-04 Electrodynamic device
GB14918/27A GB275567A (en) 1926-08-04 1927-06-07 Electrodynamic devices for use in acoustic devices, such as loud-speakers
DEE35798D DE527965C (de) 1926-08-04 1927-06-11 Elektrodynamisches Schallgeraet mit zylindrischer Tauchspule
FR636865D FR636865A (fr) 1926-08-04 1927-06-30 Perfectionnements aux dispositifs électro-dynamiques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US127152A US1707544A (en) 1926-08-04 1926-08-04 Electrodynamic device

Publications (1)

Publication Number Publication Date
US1707544A true US1707544A (en) 1929-04-02

Family

ID=22428569

Family Applications (1)

Application Number Title Priority Date Filing Date
US127152A Expired - Lifetime US1707544A (en) 1926-08-04 1926-08-04 Electrodynamic device

Country Status (5)

Country Link
US (1) US1707544A (ja)
DE (1) DE527965C (ja)
FR (1) FR636865A (ja)
GB (1) GB275567A (ja)
NL (1) NL23790C (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463762A (en) * 1941-11-14 1949-03-08 Automatic Elect Lab Electroacoustical transducer
US2485405A (en) * 1944-04-21 1949-10-18 Stromberg Carlson Co Dipole microphone
US2832844A (en) * 1957-04-29 1958-04-29 Univ Loudspeakers Inc Speaker driver
US5878149A (en) * 1993-10-08 1999-03-02 Pioneer Electronic Corporation Loudspeaker having a yoke, magnet, cylindrical throat, and spacer plate configuration
EP4287645A2 (en) 2022-05-09 2023-12-06 B&C Speakers S.P.A. Acoustic compression chamber with modally coupled annular diaphragm
EP4373132A1 (en) 2022-11-18 2024-05-22 B&C Speakers NA (USA), LLC Phase plug for compression driver

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE902015C (de) * 1940-09-04 1954-01-18 Klangfilm Gmbh Druckkammerlautsprecher
DE911143C (de) * 1951-11-25 1954-05-10 Siemens Ag Lautsprechersystem mit Druckkammer und einer Zwiebel fuer die Schallfuehrung

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463762A (en) * 1941-11-14 1949-03-08 Automatic Elect Lab Electroacoustical transducer
US2485405A (en) * 1944-04-21 1949-10-18 Stromberg Carlson Co Dipole microphone
US2832844A (en) * 1957-04-29 1958-04-29 Univ Loudspeakers Inc Speaker driver
US5878149A (en) * 1993-10-08 1999-03-02 Pioneer Electronic Corporation Loudspeaker having a yoke, magnet, cylindrical throat, and spacer plate configuration
EP4287645A2 (en) 2022-05-09 2023-12-06 B&C Speakers S.P.A. Acoustic compression chamber with modally coupled annular diaphragm
EP4373132A1 (en) 2022-11-18 2024-05-22 B&C Speakers NA (USA), LLC Phase plug for compression driver

Also Published As

Publication number Publication date
NL23790C (ja)
GB275567A (en) 1928-01-19
DE527965C (de) 1931-06-24
FR636865A (fr) 1928-04-18

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