US1642777A - Receiver - Google Patents

Receiver Download PDF

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Publication number
US1642777A
US1642777A US746791A US74679124A US1642777A US 1642777 A US1642777 A US 1642777A US 746791 A US746791 A US 746791A US 74679124 A US74679124 A US 74679124A US 1642777 A US1642777 A US 1642777A
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United States
Prior art keywords
diaphragm
receiver
magnetic
magnetizing
iron
Prior art date
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Expired - Lifetime
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US746791A
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English (en)
Inventor
Warren C Jones
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
Western Electric Co 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
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US746791A priority Critical patent/US1642777A/en
Application granted granted Critical
Publication of US1642777A publication Critical patent/US1642777A/en
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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
    • H04R13/00—Transducers having an acoustic diaphragm of magnetisable material directly co-acting with electromagnet
    • H04R13/02—Telephone receivers

Definitions

  • This invention relates to telephone receivers, and its object is a telephone receiver of improved efficiency and moreover one that is stable in its operating characteristics under severe service conditions.
  • the invention is particularly applicable to subscriber station receivers of the electro magnetic type, although it is not limited to this type.
  • the requirements for a receiver of this type are of such a nature that it is not only necessary that the receiver be an eflicient transducer for converting the electrical energy of the speech currents into sound energy, but it should preferably reach its maximum efficiency at a low magnetizing current such as would be present on long subscriber loops where'the attenuation is a maximum.
  • the construction of the receiver should be such that its efficiency of operation is not materially altered when the instrument is subjected to wide temperature variations such as might be experienced in extreme cases.
  • the magnitude of the steady force resulting from the polarizing flux at high magnetizing currents also has an important bearing on the stability of the receiver, since it 'is influential in determining the minimum separation which may be employed between the diaphragm and the pole pieces.
  • the magnetizing current is determined by the resistance external to the receiver, the magnetizing force necessary for establishing the polarizing flux is dependentupon the number of turns in the winding, a fact which obviously reacts upon the electrical impedance of the receiver.
  • This impedance if maximum operating efliciency is to be obtained, is fixed by the electrical impedance of the apparatus at the subscriber station and by the acoustic impedance of the ear, since under these conditions the impedance looking into the receiver must be the same as the impedance looking towards the line. In the case of the present subscriber sets this impedance does not permit winding the receiver with a sufficient number of turns to provide the magnetizing force necessary to bring the circuit up to maximum efficiency.
  • the diaphragm and pole pieces are so dimensioned and spaced with respect to each other that the receiver reaches its maximum efficiency at much lower magnetizing forces than has been possible heretofore.
  • Still another feature consists in constructing the magnetic portion of the receiver so that changes in temperature will not cause marked variation in the operating air-gap which will be reflected in the efliciency of the receiver.
  • FIG. 1 is an explodedview in perspective of a preferred form ofelectromagnetic re DCVER embodying the features of the invention
  • Fig. 2 is a view partly in section of the assembled receiver shown in Fig. 1;
  • Fig. 4 are curves showing the improved eificiency obtained by following this construction.
  • the pole piece consists of two U-shaped members 9, 9 positioned as shown to provide the common central leg 6 and are welded or otherwise intimately secured to the plate 10, which in turn is secured to the bottom of cup-shaped member 7 40 by means of screws 11.
  • the flanged portion 8 is provided with a peripheral rmg 12 adapted to serve'as a seat for the diaphragm 13.
  • a late member 14 provided with a series o perforations 15, 15 is adapted to be mounted adjacent the diaphragm and serve as a magnetic shunt therefor in the manner to be explained hereinafter.
  • the flanged portion 8, diaphragm 13 and plate 14 are assembled as a unit and are clamped together by means of an inner clamping ring 16 threading into an outer clamping ring 17.
  • This assembled unit is adapted to be mounted in a standard form of receiver cup 18 which may be either of metal or of an insulating material such as hard rubber and bn which is threaded a receiver cap 19 which also serves as an ear piece. 7
  • the ole pieces 9, 9, diaphragm 13 and prefera ly the plate 14 are composed of a magnetic material having an effective permeability at low magnetizing forces very much higher than that of iron, a lower hysteresis factor, and a resistivity of the order of 45 microhms per centimeter cube. To obtain 65 this material, iron and nickel are fused to- Fig. 3 is a view of the magnetic shunt em- 1 form to be worked over for this purpose.
  • the finished parts are subjected to a heat treatment which, for particular cases, varies somewhat as regards the tempertures employed and the duration of the heating and cooling periods.
  • the optimum values of these variables may readily be determined for a specific case by experi ment.
  • the preferred composition consisting of 55% iron and 45% nickel,
  • a suitable heat treatment has been found to be to heat the material to a temperature of 1100 C. and then to'cool at the rate of approximately 4 C. per minute. This rate of cooling is not critical but can be varied over wide limits.
  • the magnetic material obtained in this manner has an extremely high effective permeability at low magnetizing forces and saturates at a point considerably 11o below that of magnetic iron.
  • the effective permeability of this material to small alternating currents with various values of direct current superimposed is shown graphically in a copending application of George W. 11 Elmen Serial No. 747,718 filed Nov. 4,1924,
  • the material After the heat treatment, the material, to maintain a high. constant value of permeability must be guarded against any considerable strains, and therefore this treatment is preferably applied to the material in its finished form.
  • Fig. 4 are curves showing-the improvement in operating efliciency resulting from embodying the various features of the invention in the magnetic'circuit of a receiver.
  • Curve A shows the improvement in transmission units or mile-s gained in transmission with an electromagnetic receiver employing the improved alloy for pole pieces but with a standard ferro type diaphragm, as compared with a standard type of subscribers station receiver.
  • Curve B shows the additional improvement resulting from replacing the ferro type diaphragm with a diaphragm of the proper'thickness composed of the improved alloy.
  • Curve C shows the gain in efficiency at high magnetizing currents when employing a mag netic shunt for the diaphragm.
  • curve B a maximum gain in efliciency equivalent to nine transmission units, but what is even more important this maximum gain is obtained with a smaller magnetizing current, approximately 35 milliamps-res, which corresponds to an energizing force of 42 ampere turns.
  • curve B drops ofl rapidly slightly beyond its maximum point and approaches curve A. This rapid drop in efliciency is due to the early saturation of the diaphragm and it was to overcome this "rapid decrease in efliciency that the plate 14 of Fig. 1 was positioned adjacent to the diaphragm to serve as a magnetic shunt therefor by carrying a portion of the flux after the diaphragm has become saturated.
  • the improvement that can be effected by a magnetic shunt is determined largely b the minimum separation necessary to insure stable operation, since the shunt plate in relieving ,the saturated condition of the diaphragm increases the deflection ofthe diaphragm for a given magnetizing current, and causes the diaphr m to be drawn into contact with the pole pieces when operating at the larger magnetizing forces. Under normal service conditions this separation should be approximately fifteen thousandths of an inch and in no caseless than ten thousandths of an inch. I
  • the material composing the clamping surfaces should have the same linear temperature coefficient of expansion as the diaphragm, and a similar relation should exist between the unit and its supporting structure.
  • the changes in efliciei'icy due to changes in temperature have been reduced to a minimum by providing a material having the same temperature coefficient for the diaphragm, pole pieces, and clamping members.
  • An electromagnetic receiver embodying the features of this invention was tested for transmission efiici-cncy, then subjected to a temperature of 20 below zero F., after which it was raised to a temperature of 160 F. and then allowed to cool to room temperature, whereupon it was tested and found to have shown no appreciable change in efliciency.
  • this construction arrangements are made for clamping the various portions of the magnetic structure together, thus obtaining the advantages of unit construction.
  • an energizing winding a magnetic circuit therefor includlih) ing a vlbrating diaphragm approaching saturation at low ma netizing forces, and means for relieving t e saturated condition of the diaphragm.
  • an energizing winding - a magnetic circuit therefor including a vibrating diaphragm approaching saturation at low magnetizing forces, and a magnetic shunt for said diaphragm.
  • an energizing winding including'a vibrating diaphragm approaching saturation at low magnetizing forces, and a magnetic member mounted adjacent the diaphragm thereof. 7 a
  • an energizing to relieve the saturated condition winding a magnetic circuit therefor including a vibrating diaphragm approaching saturation at low magnetizing forces, and a magnetic shunt for said diaphragm operable only upon large magnetizing currents traversing said winding to relieve the saturated condition of the diaphragm.
  • an energizing winding a magnetic circuit'therefor including pole pieces and a vibrating diaphragm saturated at low magnetizing forces and a magnetic plate mounted adjacent to but separated from the diaphragm at portions in alignment with the pole pieces by an air gap of not less than .010 of an inch.
  • an energizing winding including a vibrating diaphragm saturated at low magnetizing forces and a magnetic shunt composed of a' material having a higher permeability than iron at low magnetizing forces and'a lower saturation point.
  • an energizing Winding a magnetic circuit therefor including a vibrating diaphragm saturated at low magnetizing forces, and a magnetic shunt composed of an alloy containing substantially nickel and 55% iron.
  • an enfor composed of an alloy containing approximately 45% nickel and iron, said magnetic circuit being so proportioned that the receiver reaches its maximum efiiciency at an energizing force of less than 5.0 ampere turns.
  • an energizing winding a magnetic circuit therefor including a vibrating diaphragm, said diaphragm being composed of an alloy containing approximately 45% nickel and 55% iron, and having a thickness of approximately .006", said diaphragm being separated. from the pole pieces by an air gap of approximately .008.
  • an energizing winding including a vibrating diaphragm, a magnetic shunt for said diaphragm, and means for locking said parts in position to provide a unitary structure.
  • an energizing winding including a vibrating diaphragm, a magnetic shunt for said diaphragm, and a pair .of clamping rings cooperating to lock said parts in position to provide a unitary structure.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Soft Magnetic Materials (AREA)
  • Hard Magnetic Materials (AREA)
US746791A 1924-10-30 1924-10-30 Receiver Expired - Lifetime US1642777A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US746791A US1642777A (en) 1924-10-30 1924-10-30 Receiver

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US746791A US1642777A (en) 1924-10-30 1924-10-30 Receiver
GB17546/25A GB248245A (en) 1925-07-08 1925-07-08 Improvements in telephone receivers

Publications (1)

Publication Number Publication Date
US1642777A true US1642777A (en) 1927-09-20

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ID=10097071

Family Applications (2)

Application Number Title Priority Date Filing Date
US746791A Expired - Lifetime US1642777A (en) 1924-10-30 1924-10-30 Receiver
US747718A Expired - Lifetime US1642778A (en) 1924-11-04 1924-11-04 Receiver

Family Applications After (1)

Application Number Title Priority Date Filing Date
US747718A Expired - Lifetime US1642778A (en) 1924-11-04 1924-11-04 Receiver

Country Status (4)

Country Link
US (2) US1642777A (enrdf_load_stackoverflow)
FR (1) FR604660A (enrdf_load_stackoverflow)
GB (1) GB248245A (enrdf_load_stackoverflow)
NL (1) NL17195C (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443667A (en) * 1982-01-11 1984-04-17 Bell Telephone Laboratories, Incorporated Electromagnetic transducer
USD539790S1 (en) * 2006-03-02 2007-04-03 Cheng Uei Precision Industry Co., Ltd. Microphone can shell

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443667A (en) * 1982-01-11 1984-04-17 Bell Telephone Laboratories, Incorporated Electromagnetic transducer
USD539790S1 (en) * 2006-03-02 2007-04-03 Cheng Uei Precision Industry Co., Ltd. Microphone can shell

Also Published As

Publication number Publication date
FR604660A (fr) 1926-05-11
GB248245A (en) 1926-03-04
US1642778A (en) 1927-09-20
NL17195C (enrdf_load_stackoverflow)

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