Speaker edge, method of foam-molding the same,apparatus for foam-molding the same, speaker edge foam-molding system, and speaker employing the speaker edge

• US 20030106740A1
• Filed: 07/01/2002
• Published: 06/12/2003
• Est. Priority Date: 10/26/2000
• Status: Active Grant

• Current Assignee: Sunstar Engineering Inc (Hosei Gijuku Luxembourg SA)
• Original Assignee: Sunstar Engineering Inc (Hosei Gijuku Luxembourg SA), Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Tabata, Shinya, Takahashi, Yoshiyuki, Ikeda, Kiyoshi, Yamazaki, Hiroki, Takada, Masaharu, Mizone, Shinya, Okuda, Shinji
• Granted Patent: US 6,680,430 B2
• Time in Patent Office: Days
• US Class Current: 181/171
• CPC Class Codes: B29C 2035/0811 using induction
• CPC Class Codes: B29C 44/1271 the preformed parts being partially covered
• CPC Class Codes: B29C 44/3415 Heating or cooling
• CPC Class Codes: H04R 2231/003 Manufacturing aspects of the outer suspension of loudspeaker or microphone diaphragms or of their connecting aspects to said diaphragms
• CPC Class Codes: H04R 2307/204 Material aspects of the outer suspension of loudspeaker diaphragms
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003
• CPC Class Codes: H04R 7/20 Securing diaphragm or cone resiliently to support by flexible material, springs, cords, or strands

Abstract

A speaker edge is made of a thermosetting composition consisting of a polyurethane prepolymer and an inactivated solid polyamine as a latent hardener. A gas is dispersed in the thermosetting composition, prior to feed into a mold, so that it can foam and solidify to give the speaker edge. In a method of making the speaker edge, the composition will be injected into a female mold segment heated below the critical thermosetting temperature, foaming the composition. Then placed in the female segment is a male segment heated above the critical temperature, causing the ingredients to react with each other to solidify in the mold. An apparatus for making the speaker edge from the composition has: a device for intake of a gas, another device for injecting the composition into the gas, another device for mechanically dispersing the gas throughout the composition, still another device for injection of this gas-containing composition into a female mold segment, a further device for placing a male segment in the female segment, and a still further device for solidifying the composition, while foaming it.

Claims

1. A speaker edge made of a thermosetting composition whose main ingredients are a polyurethane prepolymer and a latent hardener, and the latent hardener being an inactivated solid polyamine, wherein a gas is dispersed in the thermosetting composition, prior to feed thereof into a mold, so that the composition subsequently foams and solidifies itself in the mold to give the speaker edge.

2. A speaker edge as defined in claim 1, wherein the speaker edge is adhered to and integral with the main body of a vibration plate.

3. A speaker edge as defined in claim 1 or 2, wherein internal void cells produced in the speaker edge consist solely of closed cells, or consist a mixture of closed cells and open cells.

4. A speaker edge as defined in claim 1, 2 or 3, wherein the internal void cells are of a size falling within a range of 1μ

to 100μ

.

5. A speaker edge as defined in any of the preceding claims 1 to 4, wherein the internal void cells have diameters whose average is 20μ

and are distributed beside this average as a median diameter.

6. A speaker edge as defined in any of the preceding claims 1 to 5, wherein it has a density falling within a range of 0.15-0.9 g/cm³.

7. A speaker edge as defined in any of the preceding claims 1 to 6, wherein it has a skin layer whose surface is embossed with the pattern of the mold'"'"'s internal surface.

8. A speaker edge as defined in any of the preceding claims 1 to 7, wherein it has the skin layer smoothly continuing to an inner core of said edge, without any apparent or distinctive boundary intervening between them.

9. A speaker edge as defined in any of the preceding claims 1 to 8, wherein it has an arcuate portion whose thin basal ends are at least of the same density as that of the remaining thicker regions.

10. A method of making a speaker edge, the method comprising the steps of:

preparing a thermosetting composition whose main ingredients are a polyurethane prepolymer and a latent hardener, the latent hardener being an inactivated solid polyamine,

then mechanically dispersing a gas throughout the thermosetting composition,

thereafter injecting this composition into a female mold segment that has been heated to a temperature below the intrinsic critical thermosetting temperature of the composition, allowing it to start to foam, and

subsequently putting a male mold segment in the female segment, wherein the male segment has been heated to a higher temperature above the critical temperature so that the ingredients react with each other to solidify within the mold.

11. The method as defined in claim 10, wherein a high-frequency induction heater is used to solidify the foamed thermosetting composition.

12. An apparatus for making from a thermosetting composition a speaker edge, the apparatus comprising:

#1. a suction device linked to a piston-type pump having a cylinder in which the piston reciprocates, the device acting to suck air into the cylinder during suction stroke of the piston;

#2. a feed device for charging the cylinder with the composition after the cylinder is filled with the gas;

#3. a stirring device for mechanically mixing with the composition with the gas during exhaustion stroke of the piston;

#4. a compression device for injecting the gas-dispersed thermosetting composition into a female segment of a mold forming the speaker edge, wherein the female segment is heated to a temperature below the thermosetting critical temperature;

#5. a pressing device for fitting a male segment in the female segment, wherein the male segment is heated to another temperature above the thermosetting critical temperature; and

#6. a molding device for foaming and solidifying therein the foamable thermosetting composition.

13. An apparatus as defined in claim 12, wherein a high-frequency induction heater is used to solidify the foamed thermosetting composition.

14. A system for making from a thermosetting composition a speaker edge, the system comprising:

(1.) a suction process using a piston-type pump that has a cylinder in which the piston reciprocates, the process being designed to suck air into the cylinder during suction stroke of the piston;

(2.) a feed process for charging the cylinder with the composition after the cylinder is filled with the gas;

(3.) a stirring process for mechanically mixing with the composition with the gas during exhaustion stroke of the piston;

(4.) a compression process for injecting the gas-dispersed thermosetting composition into a female segment of a mold forming the speaker edge, wherein the female segment is heated to a temperature below the thermosetting critical temperature;

(5.) a pressing process for fitting a male segment in the female segment, wherein the male segment is heated to another temperature above the thermosetting critical temperature; and

(6.) a molding process for foaming and solidifying therein the foamable thermosetting composition.

15. A system as defined in claim 14, wherein a high-frequency induction heater is used to solidify the foamed thermosetting composition.

16. A speaker comprising a vibration plate built therein and a speaker edge, wherein the speaker edge is made of a thermosetting composition whose main ingredients are a polyurethane prepolymer and a latent hardener, with the latent hardener being an inactivated solid polyamine, wherein a gas is dispersed in and throughout the thermosetting composition, prior to feed thereof into a mold, so that the composition foams and solidifies itself therein to give the speaker edge.