Source: https://patents.google.com/patent/EP0552040B1/en
Timestamp: 2018-07-17 14:09:52
Document Index: 381865318

Matched Legal Cases: ['arts 3', 'art 3', 'arts 3', 'art 31', 'art 32', 'art 31', 'arts 31']

EP0552040B1 - Method and apparatus for making a loudspeaker cone and surround assembly - Google Patents
Method and apparatus for making a loudspeaker cone and surround assembly Download PDF
EP0552040B1
EP0552040B1 EP19930300237 EP93300237A EP0552040B1 EP 0552040 B1 EP0552040 B1 EP 0552040B1 EP 19930300237 EP19930300237 EP 19930300237 EP 93300237 A EP93300237 A EP 93300237A EP 0552040 B1 EP0552040 B1 EP 0552040B1
EP19930300237
EP0552040A1 (en )
Patrick Arthur Leach
David Ian Leach
B29L2031/3418—Loud speakers
The invention relates to loudspeakers and more particularly to a method and apparatus for making a speaker cone and surround assembly.
Many attempts have been made to produce a loudspeaker cone and surround assembly directly by injection moulding one onto the other to avoid the need for costly hand assembly of the two components, see for example GB-A-2228391 of Pioneer. Although in theory the manufacturing technique involved appears to be simple, in practice this is not the case. This is probably due to the fact that it is particularly difficult to injection mould an elastomer to form a surround because of the poor flow characteristics of molten elastomers when moulding components of thin cross-section such as are involved in a loudspeaker suspension. Ordinary injection moulding techniques produce a surround which is lacking in concentricity and uniformity of cross-section and which is not flat at its outer margin. This is unacceptable. US-A-3 961 378 discloses a method and apparatus for making a loudspeaker cone and surround assembly wherein an elastomer is simultaneously injected at multiple positions around the periphery of the cone. Our early experiments attempted to remedy these deficiencies by simultaneously injecting the elastomer at multiple positions around the periphery of the cone but still failed to provide the whole answer.
According to the invention, a method of making a loudspeaker cone and surround assembly comprises clamping at least the outer marginal edge of a cone in a mould having a cavity defining a surround and injecting an elastomeric material into the cavity through an annular orifice extending substantially continuously around the said marginal outer edge to form a surround attached to the outer marginal edge of the cone. The elastomeric material is fed to the annular orifice through an annular feed chamber extending around the mould cavity. The annular orifice is narrow in width in comparison to the thickness of the surround and the method comprises the step of separating the surround from an annular ring of sprue formed by elastomer which has solidified in or outside the annular orifice by tearing while the elastomer is still hot from the injection moulding step.
From another aspect the invention is injection moulding apparatus for carrying out the method referred-to above, comprising mould parts defining a surround and for receiving at least the marginal outer edge of a cone, the mould parts being movable in one direction to close the mould and in another direction to open the mould to clamp the said cone edge and to allow access to the mould cavity, means formed between the mould parts and extending substantially continuously round the cavity defining an annular feed chamber for molten elastomer, and a substantially continuous annular injection orifice communicating between the annular feed chamber and the cavity. The substantially continuous annular injection port is formed by a small gap between the mould parts so that the injection port is in the form of a narrow slit through which the molten elastomer enters the mould cavity radially from the feed chamber. The feed chamber is large in cross-section compared to the annular injection orifice which will be small in width compared to the width or thickness of the cavity. The annular feed chamber will be fed from a single radially extending feed port via a constricted section of reduced cross-section which forms a 'gate' controlling the flow of molten elastomer to the cavity. Preferably this constricted section splays-out laterally in a direction towards the annular feed chamber to assist the molten elastomer to flow round the path.
The cone suspension e.g. of an elastomeric material, may be moulded integrally with a rigid annular chassis front member. Preferably the annular chassis front member, which may be moulded from a material such as polypropylene, is arranged to surround the cone suspension. Preferably the cone suspension and the cone are moulded integrally. The material of the suspension is preferably arranged to overlie an axial face of the annular chassis front member and is formed with a raised annular bead which can form a compressible water and/or air seal when the drive unit is installed. The suspension material may be moulded to embrace both opposite axial faces of the annular chassis front member, and may be formed with annular beads on both opposite faces.
Figure 1 is a plan view of a female injection mould part for forming a surround or suspension on a loudspeaker cone;
Figure 2 is a cross-sectional side view on the line A-A of Figure 1;
Figure 3 is a view of detail C of Figure 2 to an enlarged scale;
Figure 4 is a perspective view of a loudspeaker cone and surround assembly made in accordance with the present invention;
Figure 5 is a scrap cross section of part of the loudspeaker cone and suspension assembly of Figure 4, and taken on the line B-B of Figure 4;
Figure 6 is a scrap cross-sectional view corresponding to Figure 5 of a modified arrangement;
Figure 7 is a partly sectioned exploded perspective view of a loudspeaker drive unit, and
Figure 8 is a scrap cross-sectional view of the outer edge of a loudspeaker together with its surround or suspension and a moulded-on annular chassis member.
In Figures 1 to 3 of the drawings there is shown injection moulding apparatus for making loudspeaker cone and surround assemblies. To injection mould an elastomeric suspension or surround on to the outer periphery of an injection moulded loudspeaker cone, we propose an injection mould having an opposed pair of relatively movable complementary parts 3 and 7, only the female part 3 of which is shown in Figure 1 of the drawings, and both of which are shown in Figure 2. Rather than attempt to inject the elastomer directly into the cavity formed between the two mould parts 3 and 7 and which defines the shape of the surround or suspension to be injection moulded onto the outer peripheral edge 23 of an injection moulded cone 21 clamped between the mould parts and extending into the surround defining cavity, we instead inject the molten elastomer via a port 1 through a control gate 2, which is a constriction which in plan view shown in Figure 1 fans out sideways as it approaches an annular flow path or feeder 4 which extends continuously around the surround-forming cavity at a position closely adjacent to the outer edge of the cavity. The molten elastomer then enters the cavity radially through a narrow "knife edge" orifice 5 extending continuously round the outer edge of the cavity. In this way the cavity is filled evenly and simultaneously at all positions around its periphery. Thus the cavity fills with elastomer to form a surround 22 having an outer flange 6 which is thick in comparison to the thickness or width of the orifice 5, and an inner flange 17 attached to the outer margin of the cone 21.
It will be seen from Figure 3 that when the elastomer in the filled mould has solidified to form a surround 22 molecularly bonded by cross-linking to the material of the cone 21, the outer flange 6 of the surround will have an attached annular sprue 23 of rounded cross-section consisting of the solidified elastomer formerly occupying the annular feeder ring. Preferably this is detached immediately the moulded component is removed from the mould i.e. while it is still hot, and at that stage can be done manually by tearing since the elastomer will not have cured fully. We have found that the waste elastomer will separate cleanly from the outer edge of the surround since the thin cross-section of elastomer in the knife edge injection orifice 5 forms a line of weakness.
In Figures 4 to 6 of the drawings there is shown a loudspeaker drive cone and surround assembly of generally conventional appearance and comprising a frusto-conical drive cone 21 which, in use, is attached at its inner margin 11 in any convenient manner to a loudspeaker drive motor, e.g. a moving coil, not shown, the outer margin 23 of the cone 21 being attached in the manner described above with reference to Figures 1 to 3 to a compliant surround or suspension 22 which in turn is secured in any convenient fashion to a loudspeaker drive unit chassis (not shown). In the present case the loudspeaker drive cone 21 has been injection moulded from polypropylene and the flexible elastomeric surround or suspension 22, which is of generally conventional configuration, has been injection moulded thereon. The surround is annular in shape and comprises an outer flange 6 by which it is attached to the loudspeaker drive unit chassis (not shown), a part circular roll or bellows 16 which is the active part of the cone suspension and an inner flange 17, which is moulded onto the rear face 9 of the cone 21 so as to overlap the outer margin 23 of the cone to some extent. The overlapping joint is thus invisible in use. The outer edge 8 of the cone 21 is preferably positioned closely adjacent to the roll or bellows 16 of the surround 22 so that the surround does not adversely affect the acoustic properties of the cone.
In the arrangement of Figure 5, the surround 22 is injection moulded in two successive steps, in the first of which the inner annular part 31 is injected directly onto the cone 21, after which in a second step the outer annular part 32 of the surround is injected onto the inner part 31. Each of these steps will be as described above with reference to Figure 1 to 3. In this way the characteristics of the surround can be tailored in any desired fashion so that for example the acoustical properties of the surround can be improved. If desired the inner and outer parts 31,32 of the surround 22 can be of different colours for aesthetic reasons. Also the surround may be moulded in more than two steps, e.g. in three or more steps to achieve a multi-zone surround.
In the arrangement of Figure 6, a paper gasket 10 is arranged in the mould prior to the injection moulding of the surround 22, whereby the gasket 10 is bonded to the flange 6. In this way the cone and surround unit can be secured to the chassis (not shown) of a drive unit using conventional, that is, non-harmful, adhesives.
In Figure 7 of the drawings there is shown in exploded form a loudspeaker drive unit comprising a cone 21, a cone surround or suspension 22 around the outer periphery of the cone, and an annular chassis front plate or ring 14 supporting the outer margin 6 of the suspension 22. The chassis front plate 14 is supported on a series of chassis legs 9 attached to, and extending from, an annular rear chassis plate 20. The rear plate 20 carries a rear or inner cone suspension 18 and a magnet plate 24.
The cone 21 and surround 22 are made by injection moulding a thermoplastic injection moulded elastomeric material directly onto a thermoplastic cone to form an integral unit as described above with reference to Figures 1 to 3, and in the same moulding step, the elastomeric suspension 22 is moulded directly onto the chassis ring 14 which is itself an injection moulded member of mica-filled polypropylene or the like. The elastomeric material may be extended to form an integral gasket 12 which forms a bead-like flange projecting from both sides of the ring 14 and extending continuously around both sides of the ring. To this end the ring 14 is formed with a series of apertures extending through its surface from side to side to permit the elastomeric material to flow through the ring during the moulding process to form bead-like gaskets on both sides thereof.
The rear face of the ring 14 is formed integrally with frusto-conical spigots 13 which are received in correspondingly shaped sockets 28 in bosses 15 formed on the ends of chassis legs 19 and held in position by mechanical fixings such as screws or by welding, adhesives or the like. The legs 19 can be injection moulded integrally on the annular rear chassis ring 24 from a thermoplastic material such as mica-filled polypropylene or alternatively the legs can be made separately and the assembly fixed together e.g. by bolting. It will be appreciated that the chassis could be moulded in other fashions. Thus for example the legs 9 could be moulded on the front ring 14. Alternatively again the chassis could be formed as a cup-like member formed with sufficient louvres to allow air to move freely in response to cone excursions. The rear cone suspension 18 is preferably directly injection moulded onto the near chassis ring 20 from a thermoplastic elastomeric material, such as that used for the surround 22. The moulding method will be as described above with reference to Figures 1 to 3.
Figure 8 is a scrap cross-sectional view of the outer periphery 23 of a cone 21 moulded onto a suspension 22 which is moulded onto an annular chassis ring 14. This is achieved in one step by the method described above with reference to Figures 1 to 3, except that the mould is adapted to contain both the cone 22 and the ring 14 before the elastomer of the suspension is injected to unite the components.The mould is provided with a feeder 4 which forms a detachable sprue in the manner described above. Additionally the outer flange 6 of the suspension may be extended at 30 to form the annular feeder channel through which the elastomer is fed around the mould. A ring 29 can be directly moulded to the inner periphery of the suspension 18 e.g. from plastics or card to facilitate the uniting of the suspension 18 and the cone 21, e.g. by welding or by means of an adhesive.
The invention also provides a method by which loudspeaker drive units can be made and assembled using a minimum of hand labour.
A method of making a speaker cone and surround assembly (21,22) comprising the steps of clamping the outer marginal edge (23) of a speaker cone (21) in a mould (3,7) having a cavity defining a surround such that the outer marginal edge is in the cavity, feeding an elastomeric material through a substantially annular feed chamber (4) extending around the mould cavity, injecting the elastomeric material into the cavity through a substantially annular knife edge orifice (5) communicating with the feed chamber and which is narrow in width in comparison to the thickness of the surround (22) and which extends substantially continuously around the entire outer marginal edge (23) of the cone to mould a surround (22) attached to the outer marginal edge (23) of the cone (21), removing the assembly (21,22) from the mould and separating the surround from an annular ring (33) of solidified sprue formed of elastomeric material in the annular feed chamber (4) by tearing said sprue (33) from the surround (22) at the junction between the sprue and the surround formed by the annular knife edge orifice (5), the tearing step being performed while the elastomeric material is still hot from the injection step.
A method according to claim 1, characterised by the step of forming the surround (22) in two or more separate moulding steps to create a surround consisting of two or more annular bands or zones of elastomer.
A method according to claim 1 or claim 2, characterised by the step of evacuating air from the cavity prior to the injection of elastomer.
A method according to any preceding claim, characterised by the step of placing a paper or the like gasket (10) into the cavity prior to the injection of elastomer whereby the gasket becomes directly attached to the surround (22).
A method according to claim 4 when dependent on claim 3, characterised by the step of applying a vacuum to the cavity through the gasket (10) to prevent the elastomer from being drawn into the vacuum ports.
A method according to any preceding claim, characterised in that the cone (21) is an injection moulding.
A method according to any preceding claim, characterised by the step of choosing the material of the cone (21) and the material of the surround (22) such that when the surround is injected onto the cone, the two are united or bonded chemically, that is to say they become attached at a molecular level due to cross-linking of the respective materials.
A method according to any preceding claim, characterised in that the cone (21) is a homo-polymer or co-polymer of polypropylene.
A method according to any preceding claim, characterised in that the elastomer of the surround (22) is a styrene-ethylene butylene-styrene polymer.
A method according to any preceding claim, characterised by the step of placing a rigid chassis component (14) into the cavity prior to the injection of elastomer whereby chassis component becomes directly attached to the surround.
A method according to claim 10, characterised in that the chassis component (14) is formed by injection moulding.
A method according to claim 11, characterised by the step of forming the rigid chassis component (10) into an annular shape.
A method according to any one of claims 10 to 12 when dependent on claim 7, characterised by the step of choosing the material of the rigid chassis component (10) such that when the material of the surround (22) is injected onto the chassis component (10), the two are united or bonded chemically, that is to say, they become attached at a molecular level due to cross-linking of the respective materials.
Injection moulding apparatus for carrying out the method of any preceeding claim comprising mould parts (3,7) defining a surround (22) and for receiving the outer marginal edge (23) of a cone (21), the mould parts being movable in one direction to close the mould and in another direction to open the mould, to define a surround forming cavity and to clamp the said cone edge (23) and to allow access to the mould cavity respectively, means formed between the mould parts and extending substantially continuously round the cavity defining an annular feed chamber (4) for molten elastomer, and a substantially continuous annular knife edge injection orifice (5) communicating between the annular feed chamber (4) and the cavity, which injection port (5) is formed by a small gap between the mould parts so that the injection orifice is in the form of a narrow slit through which the molten elastomer enters the mould cavity radially from the feed chamber, and in that the feed chamber is large in cross-section compared to the width or thickness of the orifice.
Apparatus according to claim 14, characterised in that the annular feed chamber (4) is fed from a single radially extending feed port (1) via a constricted section (2) of reduced cross-section which forms a gate controlling the flow of molten elastomer to the cavity.
Apparatus according to claim 15, characterised in that the constricted section (2) splays-out laterally in a direction towards the annular feed chamber (4) to assist the molten elastomer to flow round the cavity.
EP19930300237 1992-01-15 1993-01-14 Method and apparatus for making a loudspeaker cone and surround assembly Expired - Lifetime EP0552040B1 (en)
GB9200774 1992-01-15
GB9200774A GB9200774D0 (en) 1992-01-15 1992-01-15 Loudspeakers
GB9209345 1992-04-30
GB9209345A GB9209345D0 (en) 1992-04-30 1992-04-30 Loudspeakers
GB9221133A GB9221133D0 (en) 1992-10-08 1992-10-08 Loudspeakers
GB9221133 1992-10-08
EP0552040A1 true EP0552040A1 (en) 1993-07-21
EP0552040B1 true EP0552040B1 (en) 1996-01-03
ID=27266005
EP19930300237 Expired - Lifetime EP0552040B1 (en) 1992-01-15 1993-01-14 Method and apparatus for making a loudspeaker cone and surround assembly
US (1) US6171534B1 (en)
EP (1) EP0552040B1 (en)
JP (2) JPH07503108A (en)
CA (1) CA2087395C (en)
DE (2) DE69301151D1 (en)
DK (1) DK0552040T3 (en)
ES (1) ES2084444T3 (en)
GB (1) GB2273678B (en)
WO (1) WO1993014608A1 (en)
US6332508B1 (en) 1997-03-12 2001-12-25 Siegfried Schriever Loudspeaker and method for producing the same
GB2281531B (en) * 1993-09-02 1997-08-06 Esseplast Spa Procedure for producing a shovel of plastic material and a shovel obtained by the above method
EP0783238A3 (en) * 1995-12-22 1998-07-01 ME.AL.-S.r.l. Method for the production and application of annular suspension edges of lound speaker diaphragms
GB9704142D0 (en) * 1997-02-28 1997-04-16 Leach David I Loudspeakers
GB9712964D0 (en) * 1997-06-19 1997-08-27 Goodmans Loudspeakers Limited Loudspeakers
GB9621644D0 (en) * 1997-10-14 1996-12-11 Kerwin Colin J Cistern bag
DE69912799D1 (en) * 1998-07-29 2003-12-18 New Transducers Ltd Loudspeaker drive unit comprising a resonant panel-shaped element
JP2000261885A (en) * 1999-03-09 2000-09-22 Inoac Corp Speaker edge
US6390232B1 (en) 1999-10-29 2002-05-21 Communications Products Corporation Speaker cone assembly
DE19957938A1 (en) * 1999-12-01 2001-06-07 Reitter & Schefenacker Gmbh Holder for a loudspeaker to be installed in motor vehicles and method for its manufacture
GB0117839D0 (en) * 2001-07-21 2001-09-12 Kh Technology Corp Loudspeaker drive units
GB0120066D0 (en) * 2001-08-17 2001-10-10 Intersurgical Ltd Anatomical mask
WO2004004410A1 (en) * 2002-06-26 2004-01-08 Matsushita Electric Industrial Co., Ltd. Loudspeaker edge
US20040094868A1 (en) * 2002-11-15 2004-05-20 Wen-Teng Yu Equipment and method of manufacturing an amplifier
US7488259B2 (en) * 2003-02-19 2009-02-10 Fukoku Co., Ltd. Resin boots for constant velocity universal joint
DE60308659T2 (en) * 2003-06-04 2007-08-23 Harman Becker Automotive Systems Gmbh speaker
KR20070033294A (en) * 2005-09-21 2007-03-26 소니온 호르젠스 에이/에스 The surround molding insert having a mechanical reinforcement
JP5471435B2 (en) * 2009-12-28 2014-04-16 パナソニック株式会社 Speaker diaphragm and the speaker and the mobile terminal apparatus using the same
WO2011122673A1 (en) * 2010-03-30 2011-10-06 株式会社ブリヂストン Method for manufacturing acoustic diaphragm
US8638975B2 (en) 2011-08-17 2014-01-28 Bose Corporation Wiper seal for passive radiator
JP5626540B2 (en) * 2012-04-02 2014-11-19 オンキヨー株式会社 Speaker diaphragm and speaker using the same
US3150441A (en) 1959-05-06 1964-09-29 Klh Res And Dev Corp Method of making a loudspeaker
DE1762520B2 (en) 1967-07-05 1975-10-16 N.V. Philips' Gloeilampenfabrieken, Eindhoven (Niederlande)
GB1538531A (en) 1975-04-29 1979-01-24 Philips Electronic Associated Electro-acoustic transducer
JPS5718399B2 (en) 1978-11-29 1982-04-16
JPS6053518B2 (en) * 1979-01-11 1985-11-26 Paionia Kk
DE7925593U1 (en) * 1979-09-10 1980-02-28 Deutsche Semperit Gmbh, 8000 Muenchen Speaker cone
DE3036876C2 (en) 1979-10-02 1983-09-08 Victor Company Of Japan, Ltd., Yokohama, Kanagawa, Jp
DE3018790A1 (en) 1980-05-16 1981-11-26 Friedrich Wilhelm Ing G Bracht Loudspeaker cone circumferential shaping - has continuous elevation on cone surface to limit lip of circular bead in contact on cone outer edge
JPS5853299A (en) 1981-09-25 1983-03-29 Seiko Instr & Electronics Ltd Dynamic speaker
NL8200690A (en) 1982-02-22 1983-09-16 Philips Nv Loudspeaker diaphragm comprising a layer of polymethacrylimide.
JPS58201496A (en) 1982-05-20 1983-11-24 Sanyo Electric Co Ltd Manufacture of diaphragm for speaker
DE3241757A1 (en) 1982-11-11 1984-05-17 Ehmann Elektrotech Oscillating insert for an electromechanical transducer and method for its manufacture
JPS60204195A (en) * 1984-03-29 1985-10-15 Trio Kenwood Corp Acoustic device member and its manufacture
JPH0681355B2 (en) * 1988-08-05 1994-10-12 ミネベア株式会社 A manufacturing method and apparatus of the speaker diaphragm
DE3831867A1 (en) * 1988-09-20 1990-03-29 Nokia Unterhaltungselektronik Membrane with bead
JPH02209215A (en) * 1989-02-10 1990-08-20 Pioneer Electron Corp Die device of diaphragm for speaker
JPH02260799A (en) 1989-03-30 1990-10-23 Pioneer Electron Corp Speaker and its manufacture
JP2670365B2 (en) * 1989-10-23 1997-10-29 ソニー株式会社 Method of manufacturing a vibration plate
DK0552040T3 (en) 1996-02-05 grant
CA2087395C (en) 2001-10-23 grant
WO1993014608A1 (en) 1993-07-22 application
DE69301151D1 (en) 1996-02-15 grant
US6171534B1 (en) 2001-01-09 grant
JP3080098B2 (en) 2000-08-21 grant
CA2087395A1 (en) 1993-07-16 application
GB2273678B (en) 1995-05-03 grant
GB2273678A (en) 1994-06-29 application
ES2084444T3 (en) 1996-05-01 grant
GB9403073D0 (en) 1994-04-06 grant
EP0552040A1 (en) 1993-07-21 application
DE69301151T2 (en) 1996-05-09 grant
JPH07503108A (en) 1995-03-30 application
US6088466A (en) 2000-07-11 Audio voice coil adaptor ring
JP2004240239A (en) 2004-08-26 Display device and method of manufacturing same
WO2000075082A1 (en) 2000-12-14 Sealing means for electrically driven water purification units and method of manufacturing thereof
US5111510A (en) 1992-05-05 Speaker and manufacturing method therefor
WO1997038842A1 (en) 1997-10-23 Elastomeric keypad and method of fabricating same
US5790682A (en) 1998-08-04 Damper for speaker
US6568503B2 (en) 2003-05-27 Loudspeaker with improved mounting structure for the surround
US6330340B1 (en) 2001-12-11 Loudspeaker with a diaphragm having integral vent bores
GB2056817A (en) 1981-03-18 A loudspeaker membrane
JPH08118421A (en) 1996-05-14 Two material molding method, mold assembly and speaker
1995-03-22 RBV Designated contracting states (correction):
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