JP5534872B2 - Electric cord fixing device - Google Patents

Description

  The present invention relates to an electric cord fixing device for a metal case, and more particularly, to an electric cord fixing device suitable for a condenser microphone.

  In a condenser microphone, in particular, a narrow directivity condenser microphone (also referred to as a gun microphone) having a microphone case 1 as a long acoustic tube as shown in FIG. 5, an electric cord is often provided from the rear end side of the microphone case 1. The microphone cord 2 is directly pulled out.

  The microphone case 1 is made of a metal cylindrical tube having a shielding function, and a unidirectional condenser microphone unit and a circuit board having an audio signal output circuit thereof are housed therein although not shown.

  A two-core shielded wire is used for the microphone cord 2 and one end thereof is connected to a predetermined terminal of the circuit board in the microphone case 1. In this example, the other end of the microphone cord 2 is connected to the phantom. A connector 3 for power connection is provided.

  The microphone cord 2 is fixed to the microphone case 1 via a cord lead fitting. An example of the prior art will be described with reference to FIGS.

  First, referring to FIG. 6, the cord lead-out fitting 4 has a cylindrical portion 4 a that is fitted into the microphone case 1, and the cylindrical portion 4 a has a screw insertion hole formed in the microphone case 1. An internal thread 4b that is aligned with 1a is provided. The screw insertion holes 1a and the female screws 4b are usually arranged at three positions at intervals of 120 °.

  A cord fixing portion 4c for the microphone cord 2 is integrally provided at the bottom center of the cylindrical portion 4a. The cord fixing part 4c is formed in a sleeve shape, and firmly fixes the microphone cord 2 by caulking.

  The shield coating 2a is exposed by folding or the like at the portion to which the microphone cord 2 is to be fixed, whereby the shield coating 2a and the cord lead metal fitting 4 are electrically connected. The two core wires are not shown for the convenience of drawing.

  A groove 4d for attaching the cord bush 5 is formed on the outer periphery of the bottom of the cylindrical portion 4a. The cord bush 5 is made of an elastic material such as rubber, and an inner flange 5a that engages with the groove 4d is formed inside the front edge.

  As an attaching procedure, after the exposed portion of the shield coating 2a exposed at one end of the microphone cord 2 is fixed to the cord fixing portion 4c by caulking or the like, as shown in FIG. Put on the cover.

  Then, as shown in FIG. 8, the cylindrical portion 4a of the cord lead metal fitting 4 is fitted into the microphone case 1, the female screw 4b is coaxially aligned with the screw insertion hole 1a, and the male screw (set screw) 6 is connected to the female screw. 4b is screwed and tightened (see Patent Document 1 as an example).

JP 2006-128850 A

  According to the above-described conventional example, the microphone cord 2 can be mechanically fixed to the microphone case 1 via the cord lead metal fitting 4, but on the other hand, from the electrical and design viewpoints, There is a problem like this.

  First, as an electrical problem, the cord lead metal fitting 4 is screwed to the microphone case 1 only at a few points (three points in the conventional example). It cannot be said that conduction with the case 1 is sufficiently taken.

  Therefore, for example, when a mobile phone that emits a strong electromagnetic wave is used in the vicinity, the electromagnetic wave enters the microphone case 1 and a semiconductor element (FET (field effect transistor) as an impedance converter) mounted on the microphone unit. ), Etc., and this may cause noise.

  Further, from the viewpoint of design, there is a problem that the appearance of the head is not good because the head of the male screw 6 appears on the outer peripheral surface of the microphone case 1.

  Accordingly, an object of the present invention is to provide an electric cord fixing device for fixing an electric cord to a metal case via a cord drawing metal fitting so that the metal case and the cord drawing metal fitting can be surely conducted and It is to improve the appearance of the design so that the head of the set screw does not appear on the outer surface.

In order to solve the above-described problems, the present invention provides a cord connected to one end of the metal case from which the electric cord is drawn out by connecting a part of the electric cord connected to a predetermined electric component housed in a cylindrical metal case. In the fixing device of the electric cord fixed through the fixing means,
The cord fixing means is inserted into the metal case together with the cord drawing metal fitting and the cord drawing metal fitting inserted into the metal case with the electric cord inserted therethrough. The cord lead-out fitting includes a metal fitting body formed in a disc shape with a predetermined thickness, and a cord fixing portion for fixing a part of the electric cord inserted through the metal fitting body. A taper surface having an outer diameter that gradually increases from the inside of the metal case and having a maximum outer diameter that is substantially the same as the inner diameter of the metal case. The metal fitting body is provided with a plurality of screw insertion holes through which male screws are inserted substantially parallel to the axis of the metal case, and the locking member is a washer-like shape facing the upper surface on the small diameter side of the metal fitting body. of And a skirt portion that is integrally connected to the outer peripheral edge of the base portion and has an end portion in contact with the small diameter side portion of the tapered surface in an unloaded state. The base portion is coaxial with the screw insertion hole. A plurality of female screws that are aligned and screwed into the male screw are formed, and the end of the skirt portion is pulled by the tapered surface as the locking member is pulled toward the metal fitting body through the male screw. The diameter of the metal case is increased so as to be in close contact with the inner surface of the metal case, and an engagement groove into which an end of the skirt portion enters is formed on the inner surface of the metal case at the close contact portion .

  In the present invention, the locking member is preferably made of a spring material, and more preferably, the skirt portion is provided with a slit parallel to the axial direction of the base portion.

  The present invention is suitable for a condenser microphone. Therefore, in the present invention, the metal case is a microphone case for a condenser microphone, the electric cord is a microphone cord having a shield coating, and the shield coating exposure of the microphone cord is performed. A mode in which the portion is fixed to the cord fixing portion and the shield coating is conducted to the microphone case via the cord lead-out fitting and the locking member is included.

  According to the present invention, a taper surface having an outer diameter that gradually increases from the inside of the metal case and a maximum outer diameter that is substantially the same as the inner diameter of the metal case is formed on the periphery of the metal body of the cord lead metal fitting. On the other hand, a skirt portion whose diameter is increased by the tapered surface is provided on the locking member side, and the end side of the skirt portion is enlarged by the tapered surface as the locking member is drawn to the metal fitting body side via the male screw. Thus, the metal case and the cord lead-out fitting can be reliably conducted through the skirt portion of the locking member by being in close contact with the inner surface of the metal case. Further, the male screw (set screw) may be inserted from the end side of the metal case, and its head does not appear on the outer surface of the metal case.

Sectional drawing which shows the isolation | separation state before the assembly in embodiment of this invention. Sectional drawing which shows the middle of the assembly in embodiment of this invention. Sectional drawing which shows the assembly completion state in embodiment of this invention. The perspective view which shows the locking member used in the said embodiment. The external view which shows a narrow directivity condenser microphone (Gun microphone). Sectional drawing which shows the isolation | separation state before the assembly of the electric cord fixing device which concerns on a prior art example. Sectional drawing which shows the assembly middle in the said prior art example. Sectional drawing which shows the assembly completion state in the said prior art example.

  Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4, but the present invention is not limited to this.

  First, referring to FIG. 1, in this embodiment, the metal case is a microphone case 1 made of a metal cylindrical tube having a shielding function, as described in the conventional example of FIG. The electric cord fixed to this is the microphone cord 2 composed of a two-core shielded wire. Moreover, the cord bush 5 which consists of elastic materials, such as rubber | gum, is provided similarly to the said prior art example.

  In this embodiment, when fixing the microphone cord 2 to the microphone case 1, a cord fixing means 100 as shown in FIG. 1 is used. The cord fixing means 100 includes a cord lead fitting 110 and a metal locking member 120 that is put on the cord lead fitting 110 and is inserted into the metal case 1.

  The cord lead-out metal fitting 110 is formed in a disk shape with a predetermined thickness, and includes a metal fitting body 111 through which the microphone cord 2 is inserted. The lower surface 111c side of the metal fitting main body 111 (on the right surface side in FIG. 1) A cord fixing portion 112 that is sleeve-like and that fixes the microphone cord 2 by caulking or the like is integrally formed.

  The metal fitting body 111 is inserted into the microphone case 1 from the rear end side of the microphone case 1, and a tapered surface 113 having a forward taper as viewed from the inside of the microphone case 1 is formed on the peripheral edge portion 111 b.

  That is, the left side in FIG. 1 on the side of the metal fitting body 111 that is inserted first into the microphone case 1 is the upper surface 111a, and the taper surface 113 has an outer diameter that is the smallest outer diameter and goes toward the lower surface 111c. It gradually increases and is formed to have a maximum outer diameter substantially the same as the inner diameter of the microphone case 1 on the lower surface 111c side.

  Further, the metal fitting main body 111 is provided with a screw insertion hole 114 through which the male screw 115 is inserted and is substantially parallel to the axis of the microphone case 1. In this embodiment, the screw insertion holes 114 are disposed at two point-symmetric positions. Apart from this, the screw insertion holes 114 may be arranged at three locations at intervals of 120 °, for example.

  A groove 116 for attaching the cord bush 5 is formed between the metal fitting body 111 and the cord fixing portion 112. Correspondingly, an inner flange 5 a that engages with the groove 116 is formed inside the front edge of the cord bush 5.

  Referring also to FIG. 4, the locking member 120 includes a washer-like base 121 that faces the upper surface 111 a on the small diameter side of the metal fitting body 111, and a skirt portion 122 that is integrally provided on the outer peripheral edge of the base 121. The whole is preferably made of a spring material.

  In the base 121, female screw holes 123 that are screwed with the male screw 115 are formed at two positions that are aligned coaxially with the screw insertion hole 114. The skirt portion 122 is formed in a cylindrical shape having a size such that the end portion 122a on the free end side contacts the small diameter side portion of the tapered surface 113 in a no-load state (natural state).

  Next, an example of an assembly procedure will be described. First, as shown in FIG. 1, the shield coating 2a is exposed at the end of the microphone cord 2 by folding or the like, and the shield coating exposed portion is inserted into the cord fixing portion 122 and fixed by caulking or the like. The two core wires are not shown for the convenience of drawing.

  Further, the locking member 120 is placed on the upper surface 111a side of the metal fitting body 111, the female female hole 123 and the screw insertion hole 114 are aligned coaxially, and the male screw 115 is inserted from the lower surface 111c side of the metal fitting body 111 to insert the female female screw hole. 123 is screwed. At this time, the male screw 115 is not tightened too strongly.

  Next, as shown in FIG. 2, the metal fitting body 111 together with the locking member 120 is inserted into the microphone case 1 from the rear end side of the microphone case 1, and then the male screw 115 is strongly tightened to fix the locking member 120 to the metal fitting. Pull toward the main body 111 side.

  Then, the end portion 122a of the skirt portion 122 expands along the tapered surface 113, and finally, the end portion 122a of the skirt portion 122 comes into close contact with the inner surface of the microphone case 1 as shown in FIG. Thereafter, the cord bush 5 is attached to the rear surface 111c side of the metal fitting body 111.

  Assembling is completed in this way, but since the inner surface of the microphone case 1 and the cord lead-out fitting 110 are reliably conducted through the skirt portion 122 over their entire circumference, the microphone of electromagnetic waves radiated from a mobile phone or the like is used. Intrusion into the case 1 can be effectively prevented.

  Further, since the male screw 115 which is a set screw does not appear on the outer surface of the microphone case 1, the appearance is improved in terms of design.

  In order to facilitate the diameter expansion of the skirt portion 122, it is preferable to form a slit 124 in the skirt portion 122 in parallel with the axial direction of the base 121 as shown in FIG. The slit 124 may be provided at one place, but is preferably provided at three places or four places at equal intervals.

  In order to more firmly fix the cord lead fitting 110 to the microphone case 1, an engagement groove 1 b as a detent in which the end portion 122 a of the skirt portion 122 enters can be formed on the inner surface of the microphone case 1. preferable.

  The present invention can be applied to condenser microphones other than the narrow directivity condenser microphone in the above-described embodiment, and can also be applied to other electric devices having a metal case and an electric cord drawn from the metal case.

1 Microphone case (metal case)
1b Engaging groove 2 Microphone cord (electric cord)
2a Shield coating 5 Cord bush 100 Cord fixing means 110 Cord lead fitting 111 Bracket body 112 Cord fixing portion 113 Tapered surface 114 Screw insertion hole 115 Male screw (set screw)
120 Locking member 121 Base 122 Skirt 123 Female thread 124 Slit

Claims (4)

Fixing of an electric cord for fixing a part of an electric cord connected to a predetermined electric component housed in a cylindrical metal case to one end side of the metal case from which the electric cord is drawn out via a cord fixing means In the device
The cord fixing means is inserted into the metal case together with the cord drawing metal fitting and the cord drawing metal fitting inserted into the metal case with the electric cord inserted therethrough. And a metal locking member
The cord lead metal fitting includes a metal fitting main body formed in a disk shape with a predetermined thickness, and a cord fixing portion for fixing a part of the electric cord inserted through the metal fitting main body. A taper surface having an outer diameter that gradually increases from the inside of the metal case and having a maximum outer diameter that is substantially the same as the inner diameter of the metal case, and the metal fitting body includes an axis of the metal case and A plurality of screw insertion holes through which male screws are inserted are almost parallel,
The locking member is provided integrally with the washer-like base portion facing the small-diameter upper surface of the metal fitting main body and the outer peripheral edge of the base portion, and the end portion of the metal fitting main body contacts the small-diameter side portion of the tapered surface in an unloaded state. A plurality of female screws that are aligned coaxially with the screw insertion hole and into which the male screw is screwed.
As the locking member is pulled toward the metal fitting body through the male screw, the end side of the skirt portion is enlarged by the tapered surface to be in close contact with the inner surface of the metal case, and the metal case at the contact location. The electric cord fixing device is characterized in that an engagement groove into which an end of the skirt portion enters is formed on the inner surface of the electric cord.   The electric cord fixing device according to claim 1, wherein the locking member is made of a spring material.   3. The electric cord fixing device according to claim 1, wherein the skirt portion is provided with a slit parallel to the axial direction of the base portion. The metal case is a microphone case for a condenser microphone, the electric cord is a microphone cord having a shield coating, a shield coating exposed portion of the microphone cord is fixed to the cord fixing portion, and the shield coating is the cord lead-out The electric cord fixing device according to any one of claims 1 to 3 , wherein the electric cord is electrically connected to the microphone case via a metal fitting and the locking member.

Images