US2994016A - Magnetic translating device - Google Patents

Magnetic translating device Download PDF

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Publication number
US2994016A
US2994016A US680765A US68076557A US2994016A US 2994016 A US2994016 A US 2994016A US 680765 A US680765 A US 680765A US 68076557 A US68076557 A US 68076557A US 2994016 A US2994016 A US 2994016A
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armature
coil
magnets
sheets
magnetic
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US680765A
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Raymond W Tibbetts
George C Tibbetts
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Tibbetts Industries Inc
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Tibbetts Industries Inc
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00Magnets
    • H01F7/06Electromagnets; Actuators including electromagnets
    • H01F7/08Electromagnets; Actuators including electromagnets with armatures
    • H01F7/14Pivoting armatures
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K33/00Motors with reciprocating, oscillating or vibrating magnet, armature or coil system
    • H02K33/02Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs
    • H02K33/04Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs wherein the frequency of operation is determined by the frequency of uninterrupted AC energisation
    • H02K33/06Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs wherein the frequency of operation is determined by the frequency of uninterrupted AC energisation with polarised armatures
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R11/00Transducers of moving-armature or moving-core type

Description

July 25, 1961 R. w. TIBBETTS ETAL 2,994,016
MAGNETIC TRANSLATING DEVICE Filed. Aug. 28, 1957 2 Sheets-Sheet 1 580 e a! 559x922; if WWVW y 1961 R. w. TIBBETTS ETAL 2,994,016
MAGNETIC TRANSLATING DEVICE Filed Aug. 28, 1957 2 Sheets-Sheet 2 IZZVBIZJ607ZS f aymrzd W 121680!!! 6607' e 6112x501; ,5? M "W United States Patent 2,994,016 MAGNETIC TRANSLATIN G DEVICE Raymond W. Tibbetts and George C. Tibbetts, Camden, Maine, assignors to Tibbetts Industries, Inc., Camden, Maine, a corporation of Maine Filed Aug. 28, 1957, Ser. No. 680,765 8 Claims. (Cl. 317-172) The present invention is concerned with magnetic translating devices having a movable armature, depending for operation on variable gaps and variable magnetic fluxes, and thereby capable of translating mechanical to electrical energy or vice versa.
A primary object of the invention is to provide a magnetic transducer in which the electrical signal coil is substantially encased in magnetic material, with the result that the undesirable sensitivity to stray magnetic fields is greatly reduced.
A further object of the invention is to provide a magnetic translating device in which the magnetically soft portions carrying polarizing flux may be minimized in thickness in order to minimize both eddy current losses and physical size.
Another object of the invention is to provide a magnetic transducer in which the electrical signal coil can readily be located with precision.
Still another object of the invention is to provide a magnetic translating unit which is highly stable and rugged, and which is compact and structurally complete, enabling it to be applied readily in a variety of complete translating assemblies.
These objects are accomplished in our invention by providing the magnetic portions which carry polarizing flux in such a way that the electrical signal coil is substantially enclosed, by feeding the gaps with polarizing flux from a large proportion of their peripheries, and by arranging whenever possible for the signal flux and polarizing flux to be approximately orthogonal in field direction in the greater part of the magnetically soft portions that carry both types of flux.
According to this invention the magnetic translating device comprises a vibratory armature with means for supporting one part of the armature while leaving another part free to vibrate transversely of a predetermined plane, characterized by magnets extending lengthwise of the armature on the opposite sides thereof which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, and sheets of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of the aforesaid plane respectively, the sheets substantially covering the armature and presenting pole faces to the vibratory part of the armature.
In a more specific aspect the invention involves means for holding the parts together including a U-shaped clip ;traddling the aforesaid sheets intermediate the magnets at one end of the device.
For the purpose of illustration typical embodiments of the invention are shown in the accompanying drawlngs in which FIG. 1 is a plan view;
FIG. 2 is a left end view;
FIG. 3 is a side view;
FIG. 4 is a right end view;
FIG. 5 is a section on line 55 of FIG. 3;
FIG. 6 is a section on line 66 of FIG. 1;
FIG. 7 is an isometric view with parts broken away;
FIG. 8 is a section like FIG. 6 showing a modified construction;
FIG. 9 is a plan view of another embodiment;
FIG. 10 is a section on line 1010 of FIG. 9;
FIG. 11 is a right end view of FIG. 9; and
FIG. 12 is an isometric view of the modification with parts broken away.
The particular embodiment of the invention shown in FIGS. 1 to 7 comprises a coil 1, which may for example be of the type disclosed and claimed in the copending application of Raymond W. Tibbetts, Ser. No. 681,393, filed August 30, 1957, now Patent No. 2,988,804, issued June 20, 1961, an armature 2 extending through the opening 3 in the coil, magnets 6 and '7 extending lengthwise of the armature on the opposite sides of the coil which are intersected by the plane of the armature, the poles of the magnets being directed transversely of the plane in corresponding directions as indicated by the letters N and S in FIGS. 2 and 4, and thin sheets 8 and 9 of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of the aforesaid plane respectively. While the coil may be mounted on one sheet only, as by adhesive, as illustrated the sheets are shaped to fit the coil snugly and hold it in position. At each end the sheets 8 and 9 converge toward the armature both laterally and longitudinally to central portions which parallel the armature in close juxtaposition thereto. At the right-hand end (FIGS. 1, 3 and 6) non-magnetic spacers 11 and 12 are interposed between the sheets and the armature and the parts are secured together by means of a screw 13. At the left-hand end the armature is free to vibrate between the pole faces 14 and 16 (FIG. 6). To transfer vibration to or from the armature a yoke 17 straddles the armature and. pinches it snugly therebetween, the yoke extending outwardly through an opening 118 in the sheet 8. At its anchored end the armature has flexible tabs 19 and 20 which may be bent toward one or the other of the sheets 8 and 9 variably to collect magnetic flux, thereby to equalize the flux flowing between the armature and each of the pole faces 14 and 16. The end-s of the coil may be connected to insulated terminals 21.
In addition to the screw 13 a non-magnetic clip 23 may be slipped over the central end portions of the sheets 8 and 9 as shown in FIG. 8. Also the sheets 8 and 9 may be secured to the magnets 6 and 7, and if desired also to the coil 1, by means of a suitable cement such as fluid epoxy resin with an amine type hardener. The clip 23 serves to define the thickness of the air gaps very accurately. Also it does away with the necessity of extending the pole faces beyond the free end of the armature for the purpose of securing them together. Thus the length of the unit is reduced, this being of prime importance in miniature devices.
The modification shown in FIGS. 9 to 12 is similar to that shown in FIGS. 1 to 7 and corresponding parts are correspondingly designated. However instead of the armature being T-shaped it is E-shaped, comprising a central portion 22 corresponding to the part 2 of the first embodiment, an end portion 23 and side portions 24. Instead of a single magnet on each side there are two magnets 26 and 27 on opposite sides of the portions 24 of the armature. As in the first embodiment the poles of the magnets are directed transversely of the plane of the armature in corresponding directions as indicated by the letters N and S in FIG. 11. Tabs 29 and 30, corresponding to tabs 19 and 20 in the first embodiment, are located on the ends of the portions 24 of the E-shaped armature, the magnets 26 and 27 being shortened to provide a space between the sheets 8 and 9 so that each tab may be bent toward either sheet.
As is well known in the art of magnetic transducers, current passing through the coil and about the armature causes circulatory signal fluxes through the paths defined by the armature and the two sheets 8 and 9. Inasmuch as the signal fluxes have opposite directions in the air gaps between the armature and the pole faces 14 and 16.
whereas the polarizing flux supplied by the magnets is in the same direction in the two gaps, the signal flux increases the total magnetic flux in one gap and decreases it in the other gap, so that the armature is deflected to actuate the yoke 17. In the opposite direction of transduction the total fiuxes in the two gaps vary oppositely as the armature is moved back and forth, causing electrical output to be induced in the coil.
An important feature of the invention consists in that the coil 1 is throughly shielded from stray magnetic fields by the magnets 6 and 7 and the sheets 8 and 9. Furthermore the pole faces 14 and 16, and the corresponding pole faces on the right end (FIGS. 1, 3 and 6), are supplied with polarizing flux from three sides, that is lengthwise of the armature from the inside and crosswise from both sides. The embodiment shown in FIGS. 1 to 7 has the further advantage that since the magnets supply polarizing flux to the sides of the sheets 8 and 9 and since the signal flux traverses the sheets in a generally lengthwise direction, the signal flux and polarizing flux are approximately orthogonal in their field directions over the greater part of the sheets, with the exception of the regions near the pole faces and near the lengthwise axis of symmetry. This is of significance because a polarizing flux perpendicular in field direction to a signal flux reduces the incremental permeability of the material for the signal flux much less than the same polarizing flux when superposed on the signal fiux in the same field direction. As a result of these latter two features, the polarizing flux density is minimized in the regions of the magnetic sheets near the gaps, and the eifect of the polarizing flux upon the incremental permeability of the sheet material for signal flux is minimized in much of the remainder of the sheets. Therefore the thickness of the sheet material may be considerably reduced as compared with conventional designs, resulting in considerably reduced eddy current losses and in a smaller unit.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
We claim:
1. A transducer comprising an electromagnetic coil having an opening therethrough, an armature extending through said opening with a part projecting from each end of the coil, means for supporting one part, the other part being free to vibrate transversely of a plane containing the axis of the coil, magnets extending lengthwise of the armature on the opposite sides of the coil which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, and sheets of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of said plane respectively, said sheets and magnets substantially enclosing the coil and having portions projecting beyond the ends of the coil, the projecting portions extending substantially parallel to the projecting ends of the armature so as to present pole faces flatwise to at least one end of the armature, whereby the coil is thoroughly shielded from stray magnetic fields and said pole faces are supplied with polarizing flux from three sides.
2. A transducer comprising an electromagnetic coil having an opening therethrough, an armature extending through said opening with a part projecting from each end of the coil, means for supporting one part, the other part being free to vibrate transversely of a plane containing the axis of the coil, magnets extending lengthwise of the armature on the opposite sides of the coil which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, and sheets of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of said plane respectively, said sheets locating the coil therebetween and having portions projecting beyond the ends of the coil, the projecting portions of the sheets extending in approximately parallel juxtaposition to the projecting ends of the armature so as to present pole faces fiatwise to the armature, whereby the coil is thoroughly shielded from stray magnetic fields and said pole faces are supplied with polarizing flux from three sides.
3. A transducer comprising an electromagnetic coil having an opening therethrough, an armature extending through said opening with a part projecting from each end of the coil, means for supporting one part, the other part being free to vibrate transversely of a plane containing the axis of the coil, magnets extending lengthwise of the armature on the opposite sides of the coil which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, and sheets of magnetic material substantially covering the coil and armature on opposite sides of said plane respectively, said sheets having portions projecting beyond the ends of the coil, the projecting portions of the sheets extending substantially parallel to the projecting ends of the armature so as to present pole faces flatwise to at least one end of the armature.
4. A transducer comprising an electromagnetic coil having an opening therethrough, an armature extending through said opening with a part projecting from. each end of the coil, means for supporting one part, the other part being free to vibrate transversely of a plane containing the axis of the coil, magnets extending lengthwise of the armature on the opposite sides of the coil which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, and sheets of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of said plane respectively, said sheets and magnets substantially enclosing the coil and having portions projecting beyond the ends of the coil, the projecting portions of the sheets at at least one end of the coil first converging towards the armature and thence continuing substantially parallel to the projecting ends of the armature so as to present pole faces fiatwise to at least one end of the armature, whereby the coil is thoroughly shielded from stray magnetic fields and said pole facesare supplied with polarizing flux from three sides, said supporting means including at least one of said sheets.
5. A transducer according to claim 4 further characterized in that said projecting portions of the sheets also converge toward each other transversely from the projecting ends of the magnets toward said pole faces.
6. A transducer comprising an electromagnetic coil having an opening therethrough, an armature extending through said opening with a part projecting from each end of the coil, means for supporting one part, the other part being free to vibrate transversely of a plane containing the axis of the coil, magnets extending lengthwise of the armature on the opposite sides thereof which are intersected by said plane, the poles of the magnets being directed transversely of the plane in corresponding directions, sheets of magnetic material substantially bridging the space between the poles of the magnets on opposite sides of said plane rmpectively, said sheets su bstantially covering the armature and having portions projecting beyond the ends of the coil, the projecting portions of the sheets extending substantially parallel to the projecting ends of the armature so as to present pole faces fiatwise to at least one end of the armature, and means for securing the parts together including a U-shaped clip straddling said projecting portions of the sheets intermediate the magnets at one end of the device.
7. A transducer comprising an electromagnetic coil having an opening therethrough, an E-shaped sheet of magnetic material the middle arm of which extends through said opening with a part projecting from each end of the coil, magnets extending lengthwise of the arms of the sheet and located on each side of each of the outside arms of the sheet, the magnets each being polarized transversely of the sheet in the same direction, and plates of magnetic material substantially bridging the free poles of the magnets and substantially covering the coil, portions of the plates projecting beyond the ends of the coil so as to present pole faces fiatwise to the unattached end of said middle arm, the unattached end of said middle arm being free to vibrate between said pole faces.
8. A transducer comprising 'an electromagnetic coil having an opening therethrough, an E-shaped sheet of magnetic material the middle arm of which extends through said opening with a part projecting from each end of the coil, magnets extending lengthwise of the arms of the sheet and located on each side of each of the outside arms of the sheet, the magnets each being polarized transversely of the sheet in the same direction, and plates of magnetic material substantially biidging the tree poles of the magnets and substantially covering the coil, of the plates projecting beyond the ends of the coil, the projecting portions at one end of the coil first converging towards said middle arm and then extending substantially parallel thereto so as to present pole faces flatwise to the unattached end thereof, said unattached end being tree to vibrate between said 10 pole faces.
References Cited in the file of this patent UNITED STATES PATENTS 15 2,433,739 Collins et al Dec. 30, 1947 2,511,114 Lavery June 13, 1950 2,582,942 Baker Jan. 22, 1952 2,912,523 Knowles et a1 Nov. 10, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N6. 2,994,016 July 25, 1961 Raymond W. Tibbetts et al.
It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read as corrected below.
Column 3, line 64, beginning with "2, A transducer" strike out all to and including "sides." in line 8, column 4; columns 4 and 5, for the claims numbered "'3, 4, 5, 6, 7, and 8;"
read 2, 3, 4, 5, 6 and 7 column 4 line 48, for the claim reference numeral "4" read 3 in the heading to the printed specification, line 7, for "8 Claims" read 7 Claims Signed and sealed this 23rd day of January 1962.
(SEAL) Attest:
ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents v UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,994,016 July 25, 1961 Raymond W, Tihbetts et al.
It is hereby certified that error appears in -the above numbered petentrequiring correction and that the said Letters Patent should read as "corrected below.-'
Column 8, line 64, beginning with "2 A transducer" strike out all to and including "sides." in line 8 column 4; columns 4 and 5, for the claims numbered ."3, 4, 5, 6, 7 and 8;" read 2, 3, 4, 5, 6 and 7 column 4, line 48, for the claim reference numeral "4" read 3 in the heading to the printed specification line 7, for "8 Claims' read 7 Claims Signed and sealed this 23rd day of January 1962.
(SEAL) Attest:
ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents
US680765A 1957-08-28 1957-08-28 Magnetic translating device Expired - Lifetime US2994016A (en)

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111563A (en) * 1960-05-05 1963-11-19 Industrial Res Prod Inc Electro-mechanical transducer
US3217728A (en) * 1962-11-13 1965-11-16 American Brake Shoe Co Torque motor servo valve assembly
US3413424A (en) * 1961-09-06 1968-11-26 Industrial Res Prod Inc Electro-acoustic transducer
US3505545A (en) * 1967-05-26 1970-04-07 Ahmet K Bey Polarized vibratory motor
US3515818A (en) * 1962-01-23 1970-06-02 Tibbetts Industries Magnetic translating device
US4108006A (en) * 1976-03-30 1978-08-22 Johnson, Matthey & Co., Limited Accelerometers
US6075870A (en) * 1996-12-02 2000-06-13 Microtronic B.V. Electroacoustic transducer with improved shock resistance
US6658134B1 (en) 1999-08-16 2003-12-02 Sonionmicrotronic Nederland B.V. Shock improvement for an electroacoustic transducer
US7065224B2 (en) 2001-09-28 2006-06-20 Sonionmicrotronic Nederland B.V. Microphone for a hearing aid or listening device with improved internal damping and foreign material protection
US7072482B2 (en) 2002-09-06 2006-07-04 Sonion Nederland B.V. Microphone with improved sound inlet port
US7236609B1 (en) 1999-10-07 2007-06-26 Knowles Electronics, Llc. Electro-acoustic transducer with resistance to shock-waves
US9859879B2 (en) 2015-09-11 2018-01-02 Knowles Electronics, Llc Method and apparatus to clip incoming signals in opposing directions when in an off state
US10945077B2 (en) 2017-12-30 2021-03-09 Knowles Electronics, Llc Electroacoustic transducer with improved shock protection

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2433739A (en) * 1943-04-23 1947-12-30 Laurence H Collins Vibrator
US2511114A (en) * 1947-06-06 1950-06-13 Bell Telephone Labor Inc Polarized electromagnet
US2582942A (en) * 1949-11-01 1952-01-22 Wheeler Insulated Wire Company Electroacoustical transducer
US2912523A (en) * 1955-10-26 1959-11-10 Industrial Res Prod Inc Electro-acoustic transducer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2433739A (en) * 1943-04-23 1947-12-30 Laurence H Collins Vibrator
US2511114A (en) * 1947-06-06 1950-06-13 Bell Telephone Labor Inc Polarized electromagnet
US2582942A (en) * 1949-11-01 1952-01-22 Wheeler Insulated Wire Company Electroacoustical transducer
US2912523A (en) * 1955-10-26 1959-11-10 Industrial Res Prod Inc Electro-acoustic transducer

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111563A (en) * 1960-05-05 1963-11-19 Industrial Res Prod Inc Electro-mechanical transducer
US3413424A (en) * 1961-09-06 1968-11-26 Industrial Res Prod Inc Electro-acoustic transducer
US3515818A (en) * 1962-01-23 1970-06-02 Tibbetts Industries Magnetic translating device
US3217728A (en) * 1962-11-13 1965-11-16 American Brake Shoe Co Torque motor servo valve assembly
US3505545A (en) * 1967-05-26 1970-04-07 Ahmet K Bey Polarized vibratory motor
US4108006A (en) * 1976-03-30 1978-08-22 Johnson, Matthey & Co., Limited Accelerometers
US6075870A (en) * 1996-12-02 2000-06-13 Microtronic B.V. Electroacoustic transducer with improved shock resistance
US6658134B1 (en) 1999-08-16 2003-12-02 Sonionmicrotronic Nederland B.V. Shock improvement for an electroacoustic transducer
US7236609B1 (en) 1999-10-07 2007-06-26 Knowles Electronics, Llc. Electro-acoustic transducer with resistance to shock-waves
US20070258616A1 (en) * 1999-10-07 2007-11-08 Knowles Electronics, Llc Electroacoustic transducer with resistance to shock-waves
US7995789B2 (en) 1999-10-07 2011-08-09 Knowles Electronics, Llc Electroacoustic transducer with resistance to shock-waves
US7065224B2 (en) 2001-09-28 2006-06-20 Sonionmicrotronic Nederland B.V. Microphone for a hearing aid or listening device with improved internal damping and foreign material protection
US7072482B2 (en) 2002-09-06 2006-07-04 Sonion Nederland B.V. Microphone with improved sound inlet port
US9859879B2 (en) 2015-09-11 2018-01-02 Knowles Electronics, Llc Method and apparatus to clip incoming signals in opposing directions when in an off state
US10945077B2 (en) 2017-12-30 2021-03-09 Knowles Electronics, Llc Electroacoustic transducer with improved shock protection

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