JP5676288B2 - Microphone cord end processing method and microphone cord - Google Patents

Description

  The present invention relates to a microphone cord, and more particularly, to a method for processing a cord end portion drawn into a microphone case.

  As shown in the sectional view of FIG. 2, the microphone cord 1 includes a plurality of core wires (insulated conductors) 2, interposition wires (tension members) 4 and shield braided wires 3 in an electrically insulating outer sheath (sheath) 5. A multi-core shield braided wire formed by wiring is preferably employed.

  The illustrated microphone cord 1 is a four-core cord, but a two-core cord may be used. Further, the intervening wire 4 is inserted as one into the cord center, but there are some intervening wires 4 that are inserted in the form of stranded wires.

  In any case, when the microphone cord 1 is connected to the microphone, the cord lead-in portion with respect to the microphone case is subjected to stress such as twisting force in addition to bending and pulling. Slip easily occurs, and electrical connection is incomplete, and in the worst case, disconnection may occur. These phenomena are likely to occur particularly in a cord drawing portion such as a tie pin type microphone having a small external shape.

  By the way, from mobile phones that have rapidly spread in recent years, a considerably strong electromagnetic wave (for example, an electric field strength that reaches tens of thousands of electric field strength generated in the city by commercial radio waves within a range of several centimeters to several tens of centimeters). Is known to be emitted.

  Therefore, when a mobile phone is used in the vicinity of the microphone and the strong electromagnetic wave is applied to the microphone, when the electrostatic shield is weak, a high-frequency current due to the electromagnetic wave enters the microphone, and in a condenser microphone, as an impedance converter Detection may be performed by a semiconductor element (FET or the like) used, and noise in the audible band may be superimposed on the audio signal and output.

  In particular, as described above, when the electrical connection at the cord lead-in portion is incomplete, a high-frequency current due to an external electromagnetic wave easily enters from the portion.

  Therefore, the present applicant has proposed an invention as Patent Document 1 for ensuring the electrostatic shield in the cord drawing portion.

  That is, in the invention of Patent Document 1, as shown in FIG. 3, when the microphone cord 1 (in this case, a two-core shield braided wire) is pulled into the microphone case 11 of the condenser microphone 10, a plastically deformable sleeve is used. A cord fixing bracket 12 having 12a is used.

  The method will be briefly described. The shield braided wire exposed portion 3a in which the shield braided wire 3 is exposed is formed at the end of the microphone cord 1, the shield braided wire exposed portion 3a is inserted into the sleeve 12a, and the sleeve 12a. The microphone cord 1 is firmly attached to the cord fixing bracket 12 by crimping.

  Then, the cord fixing metal 12 is disposed in the microphone case 11 and fixed by, for example, a disc spring 13. According to this, since the shield braided wire exposed portion 3a is electrically connected to the microphone case 11 as the ground via the cord fixing bracket 13, a more reliable electrostatic shield can be obtained.

  However, if a stress such as bending, pulling, and twisting force is applied to the microphone cord 1, a slip still occurs between the core wire 2 and the interposition wire 4. Sometimes it comes off.

  In order to prevent this slip, the sleeve 12a may be strongly caulked, but then the insulation coating of the core wire 2 is broken, and a short circuit occurs between the core wires 2 and 2 or between the core wire 2 and the shield braided wire 3. There is a risk.

  Therefore, in the patent document 2, the present applicant injects ultraviolet curable resin from the end portion of the microphone cord 1 into the outer skin 5 and irradiates the end portion with ultraviolet rays to cure the ultraviolet curable resin, thereby preventing slipping. Propose to do.

  However, since the ultraviolet rays do not reach the inside of the cord or the portion covered with the cord fixing metal 13, the effect of preventing the slip by the ultraviolet curable resin is limited to the portion where the core wire 2 and the shield braided wire 3 are exposed. It is not necessarily enough.

JP 2006-74107 A JP 2010-206662 A

  Therefore, an object of the present invention is to reliably prevent slippage between the core wire and the interposition wire at the connection end portion of the microphone cord with respect to the microphone, and to improve the electrical connection between the shield braided wire and the cord fixing bracket. .

In order to solve the above-described problems, the present invention includes a core wire, an interposed wire, and a shield braided wire made of an insulating conductor in an electrically insulating outer shell as described in claim 1, and is plastically deformable. In the microphone cord end processing method when the end of the microphone cord is inserted into the sleeve and fixed by caulking with a microphone cord that is pulled into the microphone case via a cord fixing bracket having a sleeve, A shield braided wire exposed portion is formed by exposing the shield braided wire to the end of the microphone cord in a state where the microphone cord is cut at the end of the microphone cord and the core wire is pulled out from the end of the microphone cord. And a hot melt adhesive diluted with an organic solvent from the end of the microphone cord into the outer skin. A second step of applying to the surface of the shield braided wire exposed portion, a third step of volatilizing the organic solvent of the hot melt adhesive, and inserting the shield braided wire exposed portion into the sleeve. A fourth step of crimping the sleeve so as to reduce the diameter, and fixing the end of the microphone cord to the fixing bracket; and a fifth step of cooling after heating to a temperature at which the hot melt adhesive is dissolved. DOO sequentially have rows, heating in the fifth step, by cooling, and the braided shield wire and the sleeve by breaking the hot melt adhesive layer present between said shield braid and the sleeve It is characterized by electrical connection .

In the present invention, as described in claim 2 , when the sleeve is caulked to a part of the shield braided wire exposed portion, in the second step, from the sleeve of the shield braided wire exposed portion. The hot melt adhesive is also applied to the surface of the protruding portion.

According to a third aspect of the present invention, there is provided a cord fixing including a core wire, an interposition wire and a shield braided wire made of an insulating conductor in an electrically insulating outer shell, and having a plastically deformable sleeve. A microphone cord that is pulled into the microphone case through the metal fitting and includes the microphone cord in which the cord fixing metal fitting is attached to the end portion according to the end portion processing method of claim 1, 2, or 3.

  According to the present invention, since the adhesive to be used is a hot melt adhesive, almost all of the hot melt adhesive injected into the cord is utilized, and the core wire, the interposition wire, and the shield braided wire are the fourth. Since the bonding is performed in a state where the caulking stress is applied in the process, the slip of the core wire and the interposition wire can be surely prevented.

  In addition, since the hot melt adhesive layer existing between the shield braided wire exposed portion and the sleeve of the cord fixing bracket is also destroyed by heating and cooling in the fifth step, the shield braiding wire and the cord fixing bracket are electrically connected. Connected in good condition.

  Furthermore, if there is a protruding part of the shield braided wire exposed part that is not covered by the sleeve, the wire of the shield braided wire is also corroded by applying a hot melt adhesive layer to the surface of the protruding part. Can be prevented.

The schematic diagram for demonstrating the process of the edge part processing method of the microphone cord of this invention. Sectional drawing which shows the internal wiring state of a microphone cord. Sectional drawing for demonstrating the prior art which fixes a microphone cord in a microphone case using a cord fixing metal fitting.

  Next, although embodiment of this invention is described with (a)-(d) of FIG. 1, this invention is not limited to this.

  Referring to FIG. 1 (a), a microphone cord 1 according to this embodiment is provided with a shield braided wire 3 so as to surround two core wires 2 and a plurality of intervening wires 4 made of a strong tensile tetron twisted yarn or the like. The shielded braided wire 3 is composed of a two-core shielded braided wire having an electrically insulating outer skin 5 formed on the outer periphery thereof, but may be the four-core shielded braided wire described with reference to FIG.

  Further, when the microphone cord 1 is pulled into the microphone case 11 as described with reference to FIG. 3, a cord fixing bracket 12 having a sleeve 12a that can be plastically deformed is attached to the end of the microphone cord 11. Via the microphone case 11.

  When attaching the cord fixing bracket 12, first, as shown in FIG. 1A, the microphone cord 1 is cut to a predetermined length, and the core wire 2 and the shield braided wire 3 are respectively set to a predetermined length from the cord end 1a. Pull out minutes. The intervening wire 4 is cut at the cord end 1a.

  Then, as shown in FIG. 1B, the shield braided wire 3 drawn out from the cord end 1a is folded back onto the outer skin 5 to form a shield braided wire exposed portion 3a. Unlike this, the shield braided wire exposed portion 3a is cut out by a predetermined width (length) along the axis of the cord without cutting the shield braided wire 3 from the cord end 1a. May be formed.

  Next, hot melt adhesive diluted with an organic solvent is injected into the outer skin 5 from the cord end 1a with a syringe (not shown) or the like, and is applied to the shield braided wire exposed portion 3a with an applicator such as a brush. Examples of the hot melt adhesive include Aron Melt PES (trade name) manufactured by Toa Gosei Co., Ltd.

  After stripping the organic solvent, as shown in FIG. 1 (c), the shield braided wire exposed portion 3a is covered with the sleeve 12a of the cord fixing metal fitting 12, and as shown in FIG. 1 (d), the sleeve 12a is caulked. Reduced diameter and fixed to the cord end 1a.

  And after heating to the temperature which a hot-melt-adhesive melt | dissolves by heating means, such as a heating tank and a heating burner which are not shown in figure, it cools and the process of the cord end part 1a is complete | finished.

  According to this processing method, since the adhesive used is a hot melt adhesive, almost all of the hot melt adhesive injected into the outer skin 5 (inside the cord) is utilized, and the core wire 2, the interposition wire 4 and the shield are used. Since the braided wires 3 are bonded together with caulking stress applied thereto, the core wire 2 and the intervening wire 4 can be reliably prevented from slipping.

  In addition, the hot melt adhesive layer existing between the shield braided wire exposed portion 3a and the sleeve 12a of the cord fixing metal 12 is also broken by heating and cooling, and the shield braided wire 3 and the cord fixing metal 12 are electrically good. Connected in state.

  Therefore, as shown in FIG. 3, when the cord fixing bracket 12 is mounted in the microphone case 11, the shield braided wire 3 is conducted to the microphone case 11 as the ground via the cord fixing bracket 12, and a more reliable static electricity is obtained. An electric shield is obtained.

  Furthermore, when there is a protruding portion that is not covered with the sleeve 12a in the shield braided wire exposed portion 3a, a wire material of the shield braided wire 3 is formed by applying a hot melt adhesive layer to the surface of the protruding portion. Corrosion can also be prevented.

DESCRIPTION OF SYMBOLS 1 Microphone cord 1a Cord end part 2 Core wire 3 Shield braided wire 3a Shield braided wire exposed part 4 Interposition wire 5 Outer skin 11 Microphone case 12 Cord fixing bracket 12a Sleeve

Claims (3)

A microphone cord that includes a core wire made of an insulating conductor, an interposition wire, and a shield braided wire in an electrically insulating sheath, and is drawn into a microphone case via a cord fixing bracket having a plastically deformable sleeve. In the end processing method of the microphone cord when the end portion is inserted into the sleeve and fixed by caulking,
The intervening wire is cut at the end of the microphone cord, and the shield braided wire is exposed at the end of the microphone cord in a state where the core wire is pulled out from the end of the microphone cord. A first step of forming;
A second step of injecting hot melt adhesive diluted with an organic solvent into the outer skin from the end of the microphone cord, and applying to the surface of the shield braided wire exposed portion;
A third step of evaporating the organic solvent of the hot melt adhesive;
A fourth step of inserting the shield braided wire exposed portion into the sleeve and caulking the sleeve so as to reduce the diameter, and fixing the end portion of the microphone cord to the fixing bracket;
There sequentially row and a fifth step of cooling after heating to a temperature at which the hot melt adhesive is dissolved, heating in the fifth step, the cooling, exists between the shield braid and the sleeve A method of treating an end portion of a microphone cord, comprising: breaking the hot melt adhesive layer to electrically connect the shield braided wire and the sleeve . When the sleeve is caulked to a part of the shield braided wire exposed portion, the hot melt adhesive is also applied to the surface of the portion of the shield braided wire exposed portion that protrudes from the sleeve in the second step. The microphone cord end processing method according to claim 1, wherein: Core made of insulated conductor to electrically insulating the outer skin, interposed lines and and a braided shield wire, the microphone cord is drawn into the microphone case via a cord fixing bracket having a plastically deformable sleeve, according to claim 1 or the end portion processing method of the microphone cord according to 2, microphone code the cord retention bracket attached to the end.

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