US3779336A - Diaphragm for sound transducers, method and apparatus for manufacturing it - Google Patents

Diaphragm for sound transducers, method and apparatus for manufacturing it Download PDF

Info

Publication number
US3779336A
US3779336A US00266552A US3779336DA US3779336A US 3779336 A US3779336 A US 3779336A US 00266552 A US00266552 A US 00266552A US 3779336D A US3779336D A US 3779336DA US 3779336 A US3779336 A US 3779336A
Authority
US
United States
Prior art keywords
diaphragm
front face
frame
face
plate
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
US00266552A
Other languages
English (en)
Inventor
J Bertagni
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Application granted granted Critical
Publication of US3779336A publication Critical patent/US3779336A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms

Definitions

  • Diaphragm for sound transducers and a method for manufacturing it including providing a cellular platelike member molded of granular starting material and defining a provisional flat front face and a rear face.
  • a layer including said provisional flat front face is heat severed from the plate-like member, whereby a new concavely shaped front face and plate-like member is defined, where the contiguous severed cells become sealed in themselves and sealed together at the same time as they are subject to stresses and provide a hardened surface.
  • a sheet-like member is adhered to the new front face and the curved plate-like member is then urged into substantially planar condition, whereby the sheet-like member becomes stressed and the severed cells of the new front face are subject to additional stresses, so that the resulting diaphragm has a flat front face under a higher stress than the successive cells defining said diaphragm from said front face towards said rear face, the stresses progressively decreasing from said front face towards said rear face.
  • the invention relates also to an apparatus for severing the layer including said provisional front face, from the rest of the plate-like member.
  • the present invention refers to a diaphragm to be used in sound transducers, to a method for manufacturing said diaphragm and to an apparatus for severing a layer of material from the diaphragm. More particularly, the present invention is mainly used in connection with so-called flat loudspeakers which provide an excellent high fidelity reproduction of sound, although it may likewise be used in connection with the manufacture of microphones.
  • a diaphragm to be used in sound transducers comprising a strong, stiff, plastics plate-like member formed by a continuous structure of cells and having a heat severed and sealed front face, a rear face and side faces connecting said front and rear faces, the cells defining said front face being under a higher stress than the successive cells defining said diaphragm from said front face towards said rear face, the stresses progressively decreasing from said front face towards said rear face and the surface defining said front face is hardened.
  • the invention relates also to a method for manufac-. turing a diaphragm to be used in sound transducers made of a cellular, strong, stiff plate-like member, having a front face, a rear face and side faces connecting said front and.
  • said method comprises the steps of molding granular starting material to form a granular expanded-bonded, cellular, strong, heatseverable, plastics plate-like member having a provisional flat front face, said rear face and said side faces which connect said provisional flat front face with said rear face, said plate-like member defining a marginal vibration damping portion substantially circumscribing a figure portion on the rear face, said figure portion including zones of lesser thickness than said marginal vibration damping portion; severing a layer including said provisional flat front face by means of a heated, substantially filiform member by relatively moving said heated substantially filiform member through said plate-like member and thereby sealing and contracting the severed granules defining the new front face, whereby the resulting plate-like member becomes curved with a concave substantially integrally sealed front face which is hardened.
  • an apparatus for severing a cellular strong stiff plastics plate-like member to'be used as a diaphragm, having a front face and a rear face, comprising a track, a heated substantially filiform member traversing said track and means for maintaining said substantially filiform member under tension.
  • the filiform member is an electric wire conductor which is height adjustably mounted with regard to said track and at least one pressure means upstream of said electric wire conductor above said track adapted to urge on the plate-like member to be moved along said track in order to severe a layer therefrom.
  • FIG. 1 is a perspective view showing a particular embodiment of a diaphragm in accordance with the present invention.
  • FIG. 2 is a cross-section according to line AA of FIG. 1.
  • FIG. 3 is a diaphragm showing the granular arrangement of an expanded bonded cellular strong stiff plastics plate-like member.
  • FIG. 4 is a diagram showing the behaviour of the cells if from the plate-like member of FIG. I a top layer were to be cut by means of a cold cutter, such as a knife or a saw. This embodiment does not form part of the present invention.
  • FIGS. 5, 6 and 7 are respective explicative diagrams showing the behaviour of one cell which is being cut by a heated filiform member.
  • FIG. 8 is a diagram showing a heat severed concaveshaped plate-like member.
  • FIG. 9 is an actual cross-section of a concave-shaped diaphragm.
  • FIG. 10 is a cross-sectional view of the same diaphragm of FIG. 9 which is subject to additional steps of the method of manufacture, in accordance with a further developed embodiment of the present invention.
  • FIG. 11 is a cross-sectional view showing the finished diaphragm mounted in a frame.
  • FIG. 12 is a detail in cross-sectional view of an alternative embodiment with-regard to the one shown in FIG. 14 is a diagram showing an alternative embodiment as far as the roller means are concerned in connection with the apparatus for severing a plastics platelike member, to produce the diaphragm in accordance with the invention.
  • FIGS. 1 and 2 there is shown a plate-like member 71, which is a diaphragm which has, as will be later better explained, a heat severed and solid front face 72 which is hardened and a rear face comprising a marginal vibration damping portion 73 and a central figure portion 74 which has approximately the shape of the pinna of the human ear.
  • a recess 75 which corresponds also to the thickest portion of the figure portion 74 and into which end a pair of parallel channels 76, 76.
  • the periphery of the figure portion 74 is preferably of smaller thickness than the rest of the figure portion 74 and ends into an endless channel member 77 whose bottom wall 77 is to be as near as possible to the front face 72.
  • the endless channel member 77 connects the periphery of the figure portion 74 with an edge or side wall 78 which ends in the marginal vibration damping portion 73.
  • An electromagnetic unit 79 for driving the diaphragm if the assembly operates as a loudspeaker, is schematically shown as a capsule having a pair of electric conductors 80, 80.
  • Unit 79 is to be housed into recess 75 and the conductors 80, 80 are to be housed in channel 76, 76', respectively, to be there connected to a suitable electronic circuit (not shown).
  • unit 79 Upon using the assembly as a loudspeaker, unit 79 will vibrate the figure portion 74 and thereby generate sounds, the sound generating waves of which will be blocked from movement into the marginal vibration damping portion 73 by the endless channel member 77.
  • the central portion including the recess 75 is stiffer than the remainder of the figure portion 74, which will improve the sound reproduction in the high frequency ranges.
  • the diaphragm shown in the embodiment of FIGS, 1 and 2 is manufactured by molding granular starting material to form as shown in FIG. 3 a granular expanded-bonded cellular, strong, stiff plastics plate-like member, conveniently made of polystyrene or polyurethane.
  • the plate-like member 22 consists of expanded granules which, although in FIG. 3 they are shown as all being of substantially the same size, are in practice, not so uniform. These granules 20 are welded or fused together forming in between them alveolar cells 21 which contain moisture produced during the production of the plate-like member 22.
  • the granules 20 are somewhat resilient.
  • the plate-like member 22 has a substantially parallellepipedic shape and comprises a front face 23, rear face 24 and side faces 25.
  • each layer may be formed of more than one row of granules and the granules will not be so perfectly aligned in rows as shown in FIG. 3.
  • the platelike member 22 exhibits internal damping, if a percussion force or a vibratory movement is, for instance, applied to the rear face 24, as indicated by arrow 31.
  • the granules i.e., the granular starting material, which are to be housed in a mold in order to mold the plate-like member, 71, have a certain minimum size which is being heat expanded upon molding the plate-like member.
  • the layer of granules which have to be housed in the mold cannot be below a predetermined height since otherwise, upon molding the rear face 73, 74 of the platelike member, the male stamp must remain at a certain distance from the bottom of the female mold, so that in the zone corresponding to the bottom wall 77' of the endless channel member 77, a sufficient height is maintained to assure that the plate-like member 71 has a continuous uninterrupted front face 81.
  • the granule 20' if made for instance of polystyrene, upon being cut by heat, produce at the cutting surface fiber-like filaments which melt due to the heat and form thereby a new layer at the heat severed surface.
  • the heated wire 84 enters in contact with the granule 20', there is a retraction bearing in mind that it is an expandbd granule of the granule in the zone adjacent the wire 84, which can be seen in FIG. 5 by comparing the full line drawing with the dotted line 82.
  • the lower half 20a has a concave-shaped severed surface 86 created by the stresses and the same is true for the upper half 20b, although the latter, since it is not linked to the additional intermediate layers, has a tendency to return to its original shape due to the memory of the material.
  • the lower half 20a remains with a higher stress because due to the heat effect the immediate adjacent granules have likewise changed their shape. This stress, as will be later explained in connection with FIG. 8, changes also the shape of the immediate adjacent layers 28, 29, 30 of granules see FIG. 8.
  • the process just described is repeated through a chain of welded adjacent granules, a shrinking tendency is produced, which transforms the flat-plane plate-like member 22, into a concave-shaped plate-like member 87, as shown in FIG. 8.
  • the severed front layer 26" is the one which shrinks most while the rear face layer 27 has not been substantially subject to any transformation. Therefore, the plate-like member behaves like a loaded beam member resting on spaced 7 apart supports, at least up to the neutral line thereof.
  • the successive layers 28, 29, 30 and 27, defining successive rows of cells have progressively decreasing stresses from the front face 72' towards the rear face 24'.
  • This method further automatically seals the front face 72'.
  • the surface defining the front face 72' is a hardened skinlike surface integral with said plate-like member 22 and sealing the front face.
  • FIG. 8 merely shows the behaviour of the granules of the different rows to illustrate the progressively decreasing stress arrangement
  • the resulting diaphram 88 will have the shape as shown in FIG. 9, where the bottom wall member 77 is now at the smallest possible distance with regard to the front face 72'.
  • smallest possible distance is to be understood that a thickness is provided which allows the figure portion 74 to vibrate without a breakage occurring in the portion adjacent the bottom wall member 77'. This size cannot be achieved by direct molding, but only by severing the exceedent layer in the way as just explained.
  • the front face is covered with a sheet member 32 having marginal portions 33 projecting beyond the front face 72.
  • the sheet member 32 may for instance be made of paper or fabric.
  • the face opposite the one to be adhered to the front face 72' may have a suitable decoration or design.
  • the curved plate-like member of FIG. 10 is now urged, with the adhered sheet-like member 32, into substantially planar condition as shown in FIG. 1 1. Since the granules are now also tensioned in planes parallel to their layer, they will become somewhat more flattened, so that thereby the total thickness of the plate-like member 22 is further reduced. Simultaneously, the sheet member 32 is also stretched in its own plane and in order to anchor the sheet member in its stretched state, the marginal portions 33 are now adhered at least to the side faces 25. If the length of the marginal portions 33 is. somewhat larger, they may be turned over to cover the edge portions of the rear face 24, without degrading the resulting diaphragm.
  • FIG. 12 differs over the embodiment of FIG. 11 in that the double tensioned diaphragm 71 has been urged to a substantial planar condition by means of frame 89' without thediaphragm having adhered thereto the sheet member.
  • a, preferably pre-tensioned, sheet-like member 32 is stressed on the frame 89' above, and preferably spaced apart from, the front face 72'.
  • This sheet-like member 32 is provided for decorative purpose, although if the spacing between said sheet member 32 and the front face 72 is reduced to a minimum, they enter in cooperative relationship if the vibrations are substantial upon the front face 72 contacting the sheet member 32.
  • FIG. 13 an apparatus is shown which can be used for severing the plate-like member according to the method as previously described.
  • the apparatus comprises a U-shaped casing 90 defining a track 91 on which a conveyor platform 92 moves forward and backward by means of a schematically indicated driving arrangement 93.
  • This driving arrangement 93 consists of a driving roller 94 and a driven roller 95 having cable means 96 linked to the conveyor platform 92 to move the latter in either of the directions as indicated by double arrow 97.
  • Above track 91 preferably a roller 98 in height adjustably arranged in schematically shown bearings 99.
  • a heated filiform member more particularly an electric wire 100 is arranged between a stationary height adjustable post 101 and a roller 102 over which said wire 100 runs and supports at its free end a weight 103.
  • the wire 100 is always under a suitable tension.
  • Roller 102 as well as post 101 are connected through wires 104 and 105 to an electricity supply source 106.
  • Roller 102 is likewise height adjustably supported by casing 90 only schematically indicated by double arrow 107.
  • Air cooling nozzles 108, 109 are provided adjacent the post 101 and roller 102.
  • the operation of the apparatus is as follows: the platform 92 is moved-upstream beyond the roller 98 and a plate-like member is mounted on said platform 92 which is now moved downstream passing by the roller 98 which exerts a slight pressure on the front face 23 to bypass the electrically heated wire 100 and severe the upper layer, whereby the front face 72 is formed at the same time as the resulting diaphragm becomes concavely shaped, to result in a product as shown in FIG. 9.
  • the diaphragm 88 is unloaded then from the platform 92 and subject to further treatments, as explained in connection with FIGS. and 11 as previously explained.
  • the platform is then moved upstream to receive a new load. It can be readily conceived that if two rollers 98 are provided on each side'of the electric wire 100, that then during each stroke a working operation may be performed, provided that the other roller is withdrawn to become inoperative.
  • the system of the platform 92 is merely illustrative. It could be replaced by rollers such as shown in FIG. 14. More particularly, the bottom rollers 110, 111, move the plate-like member 22 in the direction indicated by arrow 112 and the arrangement of rollers 1 10 and 111 with regard to the electric wire and the top roller 98 can be such that a cooperation in the tendency of forming the concave-shape is achieved by arranging roller 111 in a slightly higher plane than roller 110, as shown by the two dot-and-dash-lines 113, 114.
  • the electromagnetic unit 79 is housed in recess 75, which is located in the rear face portion; however, nothing speaks against the possibility that the electromagnetic unit 79 is connected to the hardened front face 72.
  • the marginal vibration damping portion 73 with a hardening layer, for instance a vinylic layer, and to connect thereto a second electromagnetic unit (not shown) which is particularly operable in the high frequency range, so as to have a more pronounced 'sound reproduction for the high pitches.
  • a hardening layer for instance a vinylic layer
  • a second electromagnetic unit (not shown) which is particularly operable in the high frequency range, so as to have a more pronounced 'sound reproduction for the high pitches.
  • a diaphragm to be used in sound transducers comprising a strong, stiff, plastics plate-like member formed by a continuous structure of cells and having a sealed front face, a rear face and side faces connecting said front and rear faces, the cells defining said front face being under a higher stress than the successive cells defining said diaphragm from said front face towards said rear face, the stresses progressively decreasing from said front face towards said rear face, and the surface defining said front face being a hardened skin-like surface integral with said plate-like member and sealing said front face, said skin-like surface having been obtained by heat severing.
  • diaphragm of claim 1 wherein said front face is substantially planar, said diaphragm being a substantially flat diaphragm, and including a sheet-like member adhered to said front face and a frame for said diaphragm, said diaphragm being connected to said frame.
  • the diaphragm of claim 1 wherein said front face is substantially planar, said diaphragm being a substantially flat diaphragm, and including a sheet-like member in front of said front face and a frame, said sheetlike member being supported by said frame, said diaphragm being connected to said frame and arranged beneath said sheet-like member in said frame.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
US00266552A 1972-06-27 1972-06-27 Diaphragm for sound transducers, method and apparatus for manufacturing it Expired - Lifetime US3779336A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US26655272A 1972-06-27 1972-06-27

Publications (1)

Publication Number Publication Date
US3779336A true US3779336A (en) 1973-12-18

Family

ID=23015050

Family Applications (1)

Application Number Title Priority Date Filing Date
US00266552A Expired - Lifetime US3779336A (en) 1972-06-27 1972-06-27 Diaphragm for sound transducers, method and apparatus for manufacturing it

Country Status (3)

Country Link
US (1) US3779336A (de)
JP (1) JPS5413969B2 (de)
DE (1) DE2332722A1 (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4003449A (en) * 1974-11-28 1977-01-18 Jose Juan Bertagni Planar diaphragm
US4257325A (en) * 1978-04-05 1981-03-24 Bertagni Jose J Mouting of a substantially planar diaphragm defining a sound transducer
FR2565058A1 (fr) * 1984-05-28 1985-11-29 Audax Diaphragme de haut-parleur
US4997058A (en) * 1989-10-02 1991-03-05 Bertagni Jose J Sound transducer
US5425107A (en) * 1992-04-09 1995-06-13 Bertagni Electronic Sound Transducers, International Corporation Planar-type loudspeaker with dual density diaphragm
US5693917A (en) * 1993-11-18 1997-12-02 Sound Advance Systems, Inc. Planar diaphragm loudspeaker
US5991424A (en) * 1995-04-28 1999-11-23 Sound Advance Systems, Inc. Planar diaphragm speaker with heat dissipator
US20040022408A1 (en) * 2002-05-02 2004-02-05 Mango Louis A. Frame structure
US20040129492A1 (en) * 2002-10-28 2004-07-08 Alejandro Bertagni Planar diaphragm loudspeaker and related methods
US6904154B2 (en) 1995-09-02 2005-06-07 New Transducers Limited Acoustic device
GB2543409A (en) * 2015-09-17 2017-04-19 Bosch Gmbh Robert Acoustic sensor having a diaphragm and an electroacoustic transducer
US20190088238A1 (en) * 2017-09-20 2019-03-21 Mitek Corp., Inc. Printable diffuser
US11849295B2 (en) 2020-06-16 2023-12-19 Sotis AG Flat loudspeaker

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56111590U (de) * 1980-01-28 1981-08-28

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1821373A (en) * 1930-01-18 1931-09-01 Blieberger Charles Loud speaker
US3596733A (en) * 1968-12-30 1971-08-03 Jose Juan Bertagni Flat diaphragm for sound transducers and method for manufacturing it

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1821373A (en) * 1930-01-18 1931-09-01 Blieberger Charles Loud speaker
US3596733A (en) * 1968-12-30 1971-08-03 Jose Juan Bertagni Flat diaphragm for sound transducers and method for manufacturing it

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4003449A (en) * 1974-11-28 1977-01-18 Jose Juan Bertagni Planar diaphragm
US4257325A (en) * 1978-04-05 1981-03-24 Bertagni Jose J Mouting of a substantially planar diaphragm defining a sound transducer
FR2565058A1 (fr) * 1984-05-28 1985-11-29 Audax Diaphragme de haut-parleur
US4997058A (en) * 1989-10-02 1991-03-05 Bertagni Jose J Sound transducer
US5425107A (en) * 1992-04-09 1995-06-13 Bertagni Electronic Sound Transducers, International Corporation Planar-type loudspeaker with dual density diaphragm
US5539835A (en) * 1992-04-09 1996-07-23 Sound Advance Systems, Inc. Planar-type loudspeaker with dual density diaphragm
US5693917A (en) * 1993-11-18 1997-12-02 Sound Advance Systems, Inc. Planar diaphragm loudspeaker
US5991424A (en) * 1995-04-28 1999-11-23 Sound Advance Systems, Inc. Planar diaphragm speaker with heat dissipator
US6904154B2 (en) 1995-09-02 2005-06-07 New Transducers Limited Acoustic device
US7158647B2 (en) 1995-09-02 2007-01-02 New Transducers Limited Acoustic device
US20050147273A1 (en) * 1995-09-02 2005-07-07 New Transducers Limited Acoustic device
US7194098B2 (en) 1995-09-02 2007-03-20 New Transducers Limited Acoustic device
US20060159293A1 (en) * 1995-09-02 2006-07-20 New Transducers Limited Acoustic device
US20040022408A1 (en) * 2002-05-02 2004-02-05 Mango Louis A. Frame structure
US7152299B2 (en) * 2002-05-02 2006-12-26 Harman International Industries, Incorporated Method of assembling a loudspeaker
US6929091B2 (en) 2002-10-28 2005-08-16 Sound Advance Systems, Inc. Planar diaphragm loudspeaker and related methods
US20040129492A1 (en) * 2002-10-28 2004-07-08 Alejandro Bertagni Planar diaphragm loudspeaker and related methods
GB2543409A (en) * 2015-09-17 2017-04-19 Bosch Gmbh Robert Acoustic sensor having a diaphragm and an electroacoustic transducer
GB2543409B (en) * 2015-09-17 2021-08-11 Bosch Gmbh Robert Acoustic sensor having a diaphragm and an electroacoustic transducer
US20190088238A1 (en) * 2017-09-20 2019-03-21 Mitek Corp., Inc. Printable diffuser
US10446131B2 (en) * 2017-09-20 2019-10-15 Mitek Corp., Inc. Printable diffuser
US11849295B2 (en) 2020-06-16 2023-12-19 Sotis AG Flat loudspeaker

Also Published As

Publication number Publication date
DE2332722A1 (de) 1974-01-10
JPS5413969B2 (de) 1979-06-04
JPS4953409A (de) 1974-05-24

Similar Documents

Publication Publication Date Title
US3779336A (en) Diaphragm for sound transducers, method and apparatus for manufacturing it
US3596733A (en) Flat diaphragm for sound transducers and method for manufacturing it
US20230254634A1 (en) Acoustic devices
US20080053745A1 (en) Electroacoustic transducer and diaphragm
CN202178854U (zh) 微型扬声器
CN109819389B (zh) 振膜成型模具
WO1983001362A1 (en) Lead-frame for an electret microphone
FR2487619A1 (fr) Transducteur electroacoustique bivoie, en particulier pour casques et microphones
CN204231656U (zh) 电声换能器
US9998820B2 (en) Acoustic resonator for audio headphones
CN1012316B (zh) 宽带扬声器
US2685935A (en) Acoustic diaphragm
US4726444A (en) Sound wave control device
JP5088377B2 (ja) スピーカおよび音響システム
CN115379361A (zh) 振膜阵列
JPS61103393A (ja) エツジレス型スピ−カ
JP2010287989A (ja) スピーカー用部材およびそれの製造方法
US8107649B2 (en) Ribbon for ribbon microphone, manufacturing method of the same, and ribbon microphone
JP3833816B2 (ja) 電気音響変換器用振動板およびその製造方法
CN207947903U (zh) 一种可调整高度的扬声器盆架
JP3200762B2 (ja) 電気音響変換器用振動板
KR20070025875A (ko) 마이크로스피커용 이중 진동판
JPH09215089A (ja) 音響波放射装置
JP2001189998A (ja) スピーカ振動板およびその製造方法
KR100714501B1 (ko) 듀얼 진동판의 제조방법