US2967914A - Telephone transmitter - Google Patents

Telephone transmitter Download PDF

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Publication number
US2967914A
US2967914A US512672A US51267255A US2967914A US 2967914 A US2967914 A US 2967914A US 512672 A US512672 A US 512672A US 51267255 A US51267255 A US 51267255A US 2967914 A US2967914 A US 2967914A
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United States
Prior art keywords
diaphragm
transmitter
conical
chamber
members
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
US512672A
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English (en)
Inventor
Harold C Pye
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.)
Automatic Electric Laboratories Inc
Original Assignee
Automatic Electric 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 BE547497D priority Critical patent/BE547497A/xx
Application filed by Automatic Electric Laboratories Inc filed Critical Automatic Electric Laboratories Inc
Priority to US512672A priority patent/US2967914A/en
Application granted granted Critical
Publication of US2967914A publication Critical patent/US2967914A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R21/00—Variable-resistance transducers
    • H04R21/02—Microphones
    • H04R21/021—Microphones with granular resistance material
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/02—Constructional features of telephone sets
    • H04M1/03—Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets

Definitions

  • the first of these features is an air chamber enclosed within the diaphragm, which chamber through suitable openings in the diaphragm wall cooperates with a rear air chamber to produce a more uniform output and an increase in the high frequency limit.
  • Another feature is the inclusion of a front screen which attenuates high intensity sound, thereby protecting the carbon cell, and preventing transmitter overloading.
  • the transmitter disclosed herein is a direct improvement on the transmitter disclosed in Patent No. 2,149,628, issued March 7, 1939, to Harold C. Pye.
  • a flat diaphragm can vibrate in sections or modes at various frequencies without transmitting this vibration to an attached carbon cell.
  • variously shaped diaphragms have been utilized. Some diaphragms have been corrugated in various ways to stiffen them, others have been shaped as conical sections or both.
  • the diaphragm is constructed to two conical members reinforced at the center to form a very stiff central section, with a circumferential flange to permit vibration of the central section as a unit. This construction eliminated sectional vibration and permitted the diaphragm to be mechanically resonant at some single frequency and has been retained in the presentinvention.
  • resonant or damping chambers located on both sides and next to the diaphragm are utilized, such as the resonant chambers 25 and 28. These chambers are tuned to frequencies other than the natural frequency of the diaphragm normally higher than the diaphragms natural frequency.
  • Such design gives a transmitter that has a rapidly rising output toward the natural frequency of the diaphragm, and then a somewhat less Patented Jan. 10, 1961 steep rise in the output curve to the upper limit of frequency response.
  • auxiliary resonating chamber would increase the overall size of the transmitter were it not for the ingenious utilization of the air chamber defined by the two conical diaphragm ,members.
  • the acoustically resistive passages in one embodiment are formed by corrugating the periphereal edge of one of the conical members, and in another option by piercing the conical member in a number of places and then covering these openings with cloth to obtain the proper resistance to the passage of air.
  • a conventional telephone transmitter is responsive to a band of frequencies in the audible range, and when used in conventional telephones under normal conditions of low ambient noise provides satisfactory articulation. However if the noise is sufficiently great, in the range of db, the signals become inarticulate. This is because the conventional carbon transmitters are designed to be most efiicient at sound pressures in the range of from 50 to 90 db (above .0002 microbar). When the sound pressure is raised to l10'db the transmitter has reached its maximum response at the regions of greatest output. Increasing the sound pressure 6 db above db results in only a 1 db increase in transmitter output and further increases of sound input result in no further increases of transmitter output. It is for this reason that talking loudly into the conventional transmitter results in only greater distortion of the speech transmitted and makes it impossible to use the range of audibility above the 110 db masked level.
  • a desirable feature of telephone transmitters is a faithful reproduction of the voice.
  • a measure of this fidelity is the response of a transmitter with frequency variations.
  • the range of frequencies transmitted by conventional telephone circuits extends from 300 to 3500 cycles.
  • the frequency response of conventional transmitters gives an output that rises with frequency from 300 cycles to 2000 cycles. This rising characteristic is intended to compensate for the attenuation of telephone cable which increases with frequency.
  • the receiver is made to respond rather uniformly from 200 up to 3000 cycles.
  • Fig. 1 is an enlarged side cross-sectional view through the center of the transmitter unit, and mouthpiece of the telephone handset;
  • Fig. 2 is a front view of the transmitter unit
  • Figs. 3 and 3a consist of views of two optional rear diaphragm member constructions
  • Fig. 4 is a graph illustrating the performance characteristics of the transmitter units made according to this invention.
  • the rear housing member of the transmitter unit is indicated by the reference character 1. It is provided with a rim 2 on the surface of which is mounted the diaphragm assembly, another rim 3 provides a mounting for a portion of the carbon cell.
  • the entire transmitter assembly is then positioned and clamped in place in the telephone handset by the mouthpiece 31, the voice passing through the openings such as 32 in the face of the mouthpiece to reach the transmitter.
  • the moving system comprising the diaphragm assembly is made of a light material such as thin duralumin sheet metal. Three separate parts are assembled together to form the diaphragm.
  • the front part or main diaphragm member 7 is conical in shape and has a relatively wide flange around its outer edge.
  • a thin cushioning ring S, a moisture proof protective element 9 completely covering the front of the diaphragm member 7, and the diaphragm member 7 are clamped between the face plate 4 and the inside of the housing member 1.
  • Behind the front diaphragm member 7 lies a rear diaphragm member 10 in the shape of a frustum of a cone.
  • This rear diaphragm member is also flanged along its outer edge and this flange is radially fluted or corrugated in the preferred embodiment of this invention (see Fig. 3). Twenty-four equally spaced flutes 0.060 inch wide and 0.0026 inch deep were found to be satisfactory.
  • FIG. 3A Another construction providing equally good acoustic qualities is shown in Fig. 3A by reference character 10a.
  • the conical section has three holes such as 29 which are covered with cloth 30 to obtain the proper acoustic resistance.
  • a dome shaped cup 11 (Fig. l) is inserted through the opening in the rear diaphragm member 10 and a flanged portion 12 of the diaphragm member 10 engages a flange 13 of the dome shaped cup 11.
  • the complete diaphragm assembly comprising the front diaphragm member 7, the rear diaphragm member 10, and the dome shaped cup 11 is then drawn together under tension to the position indicated in Fig.
  • annular chamber 26 whose boundaries are defined by the diaphragm members 7 and 10, and the cup member 11. This chamber is completely confined by the members of and is within the moving system. it cooperates acoustically with the exterior chamber 28 through the air passageways of the diaphragm assembly.
  • a ring shaped electrode 15 constructed of solid carbon is fastened to the flange 13 of the dome shaped cup 11 by the flange 13.
  • the moving electrode 15 is a fixed ring shaped carbon electrode 16 of the same shape as the moving electrode. This is mounted in the edge of the flange 19 of another dome shaped cup 18, which cup is rigidly fastened to the transmitter housing member 1 by means of the nut or threaded ring 21.
  • the cup 18 is electrically insulated from the housing member 1 by means of the ring shaped insulating washers 20 on the shank of the dome shaped cup 18.
  • This paper bellows 17 confines the granular carbon in the cell which is formed between the two cups 11 and 18 and the electrodes 15 and 16.
  • the inner surfaces of the dome shaped cups 11 and 18 in contact with the carbon granules are covered with a suitable insulating enamel so that the current flow in the microphone cell is confined to the path between the carbon electrodes 15 and 16.
  • a suitable insulating enamel so that the current flow in the microphone cell is confined to the path between the carbon electrodes 15 and 16.
  • the microphone cell may be filled with the carbon granule material.
  • the plug 23 is threaded into the opening and then the head of the plug is sheared or twisted off.
  • a disc 24 of closely woven cloth is mounted on the inside of the face plate 4 .
  • One such cloth found to be satisfactory is double filled duck, weight 12.4 oz. per square yard and a count of 89 x 31 threads per inch.
  • the purpose of disc 24 is to attenuate the sound input to the transmitter and thus prevent the transmitter from reaching its maximum response at sound pressures of db and unless the transmitter is to be used in such high ambient noise it is not included.
  • This screen in cooperation with the other improvements also causes the output of the transmitter to be relatively uniform for all frequencies between 500 cycles and 3500 cycles and provides a useable band between 200 and 5000 cycles per second as shown by curve B of the graph of Fig. 4.
  • the transmitter Because of the disc 24 the transmitter will not be saturated or operated to its maximum response by the noise level and if the user will shout into the transmitter at a higher level than the noise level, this speech will be transmitted intelligibly.
  • the uniform output of the transmitter at all frequencies between 500 cycles and 3500 cycles prevents the transmitter from saturating at some of these frequencies while still able to transmit all of the other frequencies.
  • a transmitter for use in a telephone set including, a diaphragm unit comprising two conical shaped members having their peripheries in contact defining an air chamber therebetween, passage ways in one of said conical members for permitting the movement of air to and from said chamber, and means comprising said chamber and said perforations for controlling the resonant frequency of said diaphragm.
  • a diaphragm unit comprising two conical shaped members having their peripheries in contact, a cup member having its bottom end secured to the apex of one of said conical members and its edges in contact with the other of said conical members, an annular air chamber defined around said cup member and between said two conical members, air passages in the other of said conical members for permitting the controlled movement of air to and from said chamber, means comprising said annular air chamber in cooperation with said perforations to control the resonant frequency of said diaphragm.
  • a diaphragm unit comprising members defining an acoustic resonant air chamber within said diaphragm, means defining another air chamber adjacent said diaphragm, means for controlling movement of air between said chambers, said means and said chambers cooperating to control the response of said diaphragm o sounds.
  • a diaphragm comprising a conical member and a frusto-conical member and a portion of a cylindrical microphone cell with a semispherical end, said conical and fl'USiO-COllCfii members having their concave faces and basal peripheries abutting each other, said semi-spherical end of said microphone cell projecting through the center of said frusto-conical member into the chamber formed by the abutting concave faces of said cortical and frusto-conical members and at tached to the apex of said conical member, a flange on the cylindrical end of said microphone cell portion clamping said frusto-conical member against said conical member, an exterior chamber adjacent said frusto-conical member, the basal periphery of said frusto-conical member fluted, the hollows of said flutes facing the conical member thus define a plurality of restricted passages between said chamber in
  • a diaphragm comprising two conical shaped members having their peripheries in contact, a cup member having its bottom end secured to the apex of one of said conical members and its edges in contact with the other of said conical members, an annular air chamber defined around said cup member and between said two conical members, perforations in the other of said conical members for permitting the movement of air to and from said annular chamber, cloth screens over said perforations for controlling the rate of said movement, said annular air chamber incooperation with said perforations and cloth screens effec tive to control the resonant frequency of said diaphragm.
  • a diaphragm comprising two conical shaped members having their peripheries in contact, a cup member having its bottom end secured to the apex of one of said conical members and its edges in contact with the other one of said conical members, an annular air chamber defined around said cup member and between said two conical members, perforations in the other one of said conical members for permitting the controlled passage of air to and from said chamber, means for mounting said diaphragm in said casing to form another closed annular air chamber between said other conical member and said casing, said two chambers interacting through said perforations to facilitate movement of the diaphragm at the lower voice frequencies.
  • a casing a waterproof protective membrane, a diaphragm comprising two conical shaped members having their peripheries in contact, a cup member having its bottom end secured to the apex of one of said conical members and its edges in contact with the other one of said conical members, a first annular air chamber defined around said cup member and between said two conical members, perforations in the other one of said conical members for permitting the controlled entry of air to and escape of air from said chamber, means for mounting said diaphragm in said casing so that another annular air chamber is formed between said other conical member and said casing, said other annular air chamber connected with said first chamber by means of said perforations in the other one of said conical members, and means for mounting said protective membrane in said casing to thereby protectively seal said diaphragm and said chambers from the entrance of moisture.
  • a casing, a water-proof protective membrane, a microphone cell and a diaphragm comprising two conical shaped members having their peripheries in contact, a cup member having its bottom end secured to the apex of the front one of said conical members and its edges in contact with the rear one of said conical members, an annular air chamber defined around said cup member and between said two conical members, radially positioned corrugations along the periphery of said rear conical member, the concave flutes of said corrugations facing the front conical member thus define a series of minute air passages for the entry and escape of air to said chamber, the rear portion of said casing with said diaphragm thus define another closed annular air chamber therebetween, said chambers connected by means of said air passages formed by the flutes in the rear one of said conical diaphragm members, said protective membrane located between said diaphragm and the front of said casing thereby protectively sealing said diaphragm, microphone cell and air
  • a diaphragm comprising at least two elements that enclose, an air chamber between said elements, vents for controlling the movement of air to and from said chamber, a damping element for controlling the effect of sound pressures on said diaphragm, said vents and said damping element cooperating to control the movement of said diaphragm so that the electrical output of said transmitter is substantially proportional to the intensity of the sound pressure for all sound frequencies from 500 cycles to 3500 cycles.
  • a diaphragm responds to sound waves and operates a granular carbon microphonic element to cause electrical output
  • a diaphragm including two members that include a chamber therebetween, a screen for altering the effect of sound waves on said diaphragm, a plurality of air vents in said diaphragm, said screen and said vents controlling the response of said diaphragm to sound waves of predetermined frequencies so that the electrical output of the transmitter is substantially proportional to the sound intensity at all of said predetermined frequencies.
US512672A 1955-06-02 1955-06-02 Telephone transmitter Expired - Lifetime US2967914A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE547497D BE547497A (fr) 1955-06-02
US512672A US2967914A (en) 1955-06-02 1955-06-02 Telephone transmitter

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060208610A1 (en) * 2005-03-21 2006-09-21 Jon Heim High-performance electroactive polymer transducers
US20070200468A1 (en) * 2005-03-21 2007-08-30 Heim Jonathan R High-performance electroactive polymer transducers
US20080116764A1 (en) * 2005-03-21 2008-05-22 Artificial Muscle, Inc. Electroactive polymer actuated devices
US20100033835A1 (en) * 2005-03-21 2010-02-11 Artificial Muscle, Inc. Optical lens displacement systems
US20100102677A1 (en) * 2006-12-29 2010-04-29 Heim Jonathan R Electroactive polymer transducers biased for optimal output
US9195058B2 (en) 2011-03-22 2015-11-24 Parker-Hannifin Corporation Electroactive polymer actuator lenticular system
US9231186B2 (en) 2009-04-11 2016-01-05 Parker-Hannifin Corporation Electro-switchable polymer film assembly and use thereof
US9425383B2 (en) 2007-06-29 2016-08-23 Parker-Hannifin Corporation Method of manufacturing electroactive polymer transducers for sensory feedback applications
US9553254B2 (en) 2011-03-01 2017-01-24 Parker-Hannifin Corporation Automated manufacturing processes for producing deformable polymer devices and films
US9590193B2 (en) 2012-10-24 2017-03-07 Parker-Hannifin Corporation Polymer diode
US9761790B2 (en) 2012-06-18 2017-09-12 Parker-Hannifin Corporation Stretch frame for stretching process
US9876160B2 (en) 2012-03-21 2018-01-23 Parker-Hannifin Corporation Roll-to-roll manufacturing processes for producing self-healing electroactive polymer devices

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB368344A (en) * 1930-12-04 1932-03-04 Harold Bertram Mead Improvements relating to conical diaphragms for sound reproducing and recording apparatus
US2149628A (en) * 1935-09-16 1939-03-07 Associated Electric Lab Inc Telephone transmitter
GB529869A (en) * 1938-06-18 1940-11-29 Standard Telephones Cables Ltd Improvements in telephone transmitters of the carbon granule type
US2331525A (en) * 1941-11-06 1943-10-12 Walker Electrical Company Automatic outlet box making machine
US2585052A (en) * 1948-04-23 1952-02-12 Int Standard Electric Corp Granule type acoustic transducer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB368344A (en) * 1930-12-04 1932-03-04 Harold Bertram Mead Improvements relating to conical diaphragms for sound reproducing and recording apparatus
US2149628A (en) * 1935-09-16 1939-03-07 Associated Electric Lab Inc Telephone transmitter
GB529869A (en) * 1938-06-18 1940-11-29 Standard Telephones Cables Ltd Improvements in telephone transmitters of the carbon granule type
US2331525A (en) * 1941-11-06 1943-10-12 Walker Electrical Company Automatic outlet box making machine
US2585052A (en) * 1948-04-23 1952-02-12 Int Standard Electric Corp Granule type acoustic transducer

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7923902B2 (en) 2005-03-21 2011-04-12 Bayer Materialscience Ag High-performance electroactive polymer transducers
US8183739B2 (en) 2005-03-21 2012-05-22 Bayer Materialscience Ag Electroactive polymer actuated devices
US20080116764A1 (en) * 2005-03-21 2008-05-22 Artificial Muscle, Inc. Electroactive polymer actuated devices
US7521840B2 (en) * 2005-03-21 2009-04-21 Artificial Muscle, Inc. High-performance electroactive polymer transducers
US7521847B2 (en) * 2005-03-21 2009-04-21 Artificial Muscle, Inc. High-performance electroactive polymer transducers
US20090174293A1 (en) * 2005-03-21 2009-07-09 Artificial Muscle, Inc. High-performance electroactive polymer transducers
US20090236939A1 (en) * 2005-03-21 2009-09-24 Artificial Muscle, Inc. High-performance electroactive polymer transducers
US20100033835A1 (en) * 2005-03-21 2010-02-11 Artificial Muscle, Inc. Optical lens displacement systems
US7679267B2 (en) 2005-03-21 2010-03-16 Artificial Muscle, Inc. High-performance electroactive polymer transducers
US20100231091A1 (en) * 2005-03-21 2010-09-16 Artificial Muscle, Inc. High-performance electroactive polymer transducers
CN101147271B (zh) * 2005-03-21 2010-11-10 人工肌肉有限公司 电活性聚合物换能器
US20070200468A1 (en) * 2005-03-21 2007-08-30 Heim Jonathan R High-performance electroactive polymer transducers
US7990022B2 (en) 2005-03-21 2011-08-02 Bayer Materialscience Ag High-performance electroactive polymer transducers
AU2006227189B2 (en) * 2005-03-21 2011-07-07 Bayer Materialscience Ag High-performance electroactive polymer transducers
US20060208610A1 (en) * 2005-03-21 2006-09-21 Jon Heim High-performance electroactive polymer transducers
US8072121B2 (en) 2006-12-29 2011-12-06 Bayer Materialscience Ag Electroactive polymer transducers biased for optimal output
US20100102677A1 (en) * 2006-12-29 2010-04-29 Heim Jonathan R Electroactive polymer transducers biased for optimal output
US9425383B2 (en) 2007-06-29 2016-08-23 Parker-Hannifin Corporation Method of manufacturing electroactive polymer transducers for sensory feedback applications
US9231186B2 (en) 2009-04-11 2016-01-05 Parker-Hannifin Corporation Electro-switchable polymer film assembly and use thereof
US9553254B2 (en) 2011-03-01 2017-01-24 Parker-Hannifin Corporation Automated manufacturing processes for producing deformable polymer devices and films
US9195058B2 (en) 2011-03-22 2015-11-24 Parker-Hannifin Corporation Electroactive polymer actuator lenticular system
US9876160B2 (en) 2012-03-21 2018-01-23 Parker-Hannifin Corporation Roll-to-roll manufacturing processes for producing self-healing electroactive polymer devices
US9761790B2 (en) 2012-06-18 2017-09-12 Parker-Hannifin Corporation Stretch frame for stretching process
US9590193B2 (en) 2012-10-24 2017-03-07 Parker-Hannifin Corporation Polymer diode

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