JP2008256108A - Pipe joint and overvoltage protection method for pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint capable of facilitating pipe construction while ensuring conductivity from one pipe to the other pipe to be connected with a simple structure. <P>SOLUTION: The pipe joint 1 is used for connecting a flexible pipe A and includes a joint body 26 and a conductive member 20. The flexible pipe A has a metal layer A3 on its outer peripheral surface. The joint body 26 is electrically conductive and has a pipe inserting hole 24 and a pipe insertion hole 28 which serve as an inner hole into which an end of the flexible pipe A is inserted. The conductive member 20 is arranged to surround the outer circumference of the flexible pipe A inserted in the inner hole of the joint body 26 so as to conductively connect the metal layer A3 of the flexible pipe A and the joint body 26 to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe joint used for connecting a pipe such as a flexible pipe having a conductive layer on its outer peripheral surface, and in particular, safety measures are taken against an induced lightning surge that is an overvoltage induced by a lightning strike or the like. The present invention relates to a pipe joint for flexible pipes. The flexible pipe connected to the pipe joint is piped as a gas pipe or a water pipe or the like in the wall surface of the building or under the floor.

  One conventionally known pipe joint of this type is directly connected to a conductive member provided in the insulating coating layer of the pipe (paragraphs 0022 to 0024 of Patent Document 1). , See FIG. In other words, the pipe connected to the pipe joint has a conductive member and an insulating coating layer on the outer surface of the pipe, and the pipe joint is connected to other conductive equipment or the like. Can be connected. By directly connecting the pipe joint and the conductive member of the pipe, most of the induced lightning surge during lightning strikes is guided from the conductive member of the pipe to the ground via the pipe joint and conductive equipment. . As a result, electric energy is not concentrated on one point of the tube main body, so that it is possible to prevent the tube main body from being damaged by lightning.

Japanese Patent Laid-Open No. 2003-083482

  However, although the above-mentioned patent document 1 proposes to directly connect the pipe joint and the conductive member in the pipe, the pipe joint for connecting to the conductive member has a specific configuration. It does not represent. On the other hand, considering the cost required for pipe construction, it is desirable that the construction can be easily and labor-saving.

  One of the objects of the present invention is to provide a pipe joint capable of easily constructing a pipe while ensuring the conductivity from one connected pipe to another pipe or the like with a simple structure. That is.

  The invention according to claim 1 is a pipe joint used for connecting pipes, and is characterized by including a joint portion and a conductor. Here, the tube has a conductive layer on the outer peripheral surface. The joint has an inner hole into which the end of the pipe is inserted and is conductive, and the conductor is provided so as to surround the outer periphery of the pipe inserted into the inner hole of the joint. And electrical connection between the joint portion.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the shape of the conductor is a ring shape surrounding the outer periphery of the pipe inserted into the inner hole of the joint portion. The invention according to claim 3 is the invention according to claim 2, wherein the conductor has a notch in a part of a ring-shaped periphery.

  The invention according to a fourth aspect is the invention according to the second or third aspect, wherein the conductor comprises an inner peripheral surface of an inner hole of the joint portion and a conductive layer of a pipe inserted into the inner hole. It is arrange | positioned so that both may be contacted. Further, the invention according to claim 5 is the invention according to claim 2 or claim 3, wherein the conductor includes an opening end portion (a side surface portion or an outer peripheral surface portion) of the inner hole of the joint portion, It arrange | positions so that it may contact both with the conductive layer of the pipe | tube inserted in the hole.

  The invention according to claim 6 is the invention according to any one of claims 2 to 5, wherein the conductor has a plurality of protrusions protruding toward the axial center side of the conductor. It is characterized by.

  The invention according to claim 7 is the invention according to claim 6, wherein the conductive layer of the tube is formed in a band shape so as to extend in the longitudinal direction of the tube at a part of the outer periphery of the tube, The interval in the circumferential direction of the tube between one projection of the plurality of projections and the other projection adjacent to the one projection is greater than the length in the circumferential direction of the tube in the conductive layer. Is also small.

  The invention according to claim 8 is an overvoltage of a pipe that protects the pipe from overvoltage by a pipe joint having an inner hole into which an end of the pipe having a conductive layer is inserted on the outer peripheral surface and having a conductive joint part. It is a protection method. This tube overvoltage protection method is characterized in that the conductive layer of the tube is electrically connected to the joint portion by a conductor provided so as to surround the outer periphery of the tube inserted into the inner hole.

  According to the present invention, for example, a ring shape, a C-shape (a shape in which a part of the circumference of the ring shape is notched), etc., provided so as to surround the outer periphery of the pipe inserted into the inner hole of the joint portion. The body establishes electrical connection between the conductive layer on the outer peripheral surface of the tube and the joint portion. Such a conductor is incorporated inside the inner hole of the joint portion or at the open end of the inner hole when manufacturing the pipe joint. A pipe joint using this conductor has a simple structure, and does not complicate the attachment between the pipe and the pipe joint during construction of the pipe. Furthermore, according to the shape of the conductor surrounding the outer periphery of such a tube, it is possible to reliably ensure conductivity from one tube connected to the tube joint to another tube or the like.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view showing a pipe joint for a flexible pipe according to a first embodiment of the present invention. (The upper half of the pipe joint 1 shows a state before the slide member 30 is pushed into the joint body 26 side after the pipe is inserted, and the lower half shows a state where the push of the slide member 30 is completed. (See below). The flexible pipe A connected to the pipe joint 1 has a conductive layer on the outer peripheral surface. That is, as shown in FIG. 1, the flexible tube A includes a metal corrugated tube A1 formed in an accordion shape, an insulating resin layer A4 coated on the outer peripheral surface of the metal corrugated tube A1, and an insulating resin layer. It consists of a metal layer A3, which is a conductive layer provided on the outer periphery of A4, and a resin layer A2 that covers the outer peripheral surface of the metal layer A3. For example, the metal corrugated pipe A1 is formed to be bendable by welding and corrugating to a stainless steel hoop material having a thickness of about 0.15 to 0.5 mm, and the insulating resin layer A4 is thick. It is a synthetic resin coating layer such as a soft vinyl resin having a thickness of about 0.4 to 1.0 mm.

  The resin layer A2, the metal layer A3, and the insulating resin layer A4 are, for example, seven uneven portions of the metal corrugated pipe A1 so that a predetermined length of the metal corrugated pipe A1 is exposed at the end of the flexible pipe A. Has only been removed. Further, the coating of the resin layer A2 is removed from the end portions of the coating by the four irregularities of the metal corrugated pipe A1 so that a predetermined length of the metal layer A3 is exposed. . The removal of these coatings is for conducting the metal layer A3 of the flexible pipe A and the conductor 20 (detailed later) of the pipe joint 1.

  The pipe joint 1 is mainly composed of a joint body 26 having a pipe insertion hole 24 and an inner wall surface formed in a step shape, and a cylindrical slide member 30 having a pipe insertion hole 28. Both the joint body 26 and the slide member 30 are made of a conductive metal such as stainless steel. Here, the pipe insertion hole 24 of the joint body 26 and the pipe insertion hole 28 of the slide member 30 are combined to form an inner hole of the joint part into which the end of the flexible pipe A is inserted.

  More specifically, the slide member 30 includes a head portion 30a having a large outer diameter on the flexible tube side (right side in FIG. 1) in the longitudinal direction of the flexible tube A, and a pipe joint side (same as that in the longitudinal direction of the flexible tube A). It consists of a sliding part 30b whose outer diameter is smaller than that of the head part 30a on the left side as viewed in FIG. The sliding portion 30 b of the slide member 30 is fitted so as to be slidable along the longitudinal direction of the flexible tube A from the opening end of the tube insertion hole 24.

  A water-tight O-ring 34 made of a ring-shaped elastic body is interposed between the joint step on the outer peripheral surface of the sliding portion 30b and the inner peripheral surface of the joint body 26 (tube insertion hole 24). Thus, moisture is prevented from entering the inside of the pipe joint 1 from the gap between the outer peripheral surface of the sliding portion 30b and the inner peripheral surface of the joint body 26. Further, a watertight packing 36 made of a ring-shaped elastic body is interposed between the inner peripheral surface of the head portion 30a and the outer peripheral surface of the flexible tube A, whereby the outer peripheral surface of the flexible tube A and the slide member 30 are interposed. Water is prevented from entering the inside of the pipe joint 1 through a gap with the inner peripheral surface of the pipe joint 1.

  Furthermore, the slide member 30 has a groove portion 38 having a rectangular cross section and formed in a ring shape on the outer peripheral surface on the pipe joint side in the longitudinal direction of the flexible tube A. A C-shaped stop ring member 40 with a part thereof cut away is accommodated. The stop ring member 40 is formed by, for example, spring steel having a circular cross section, and is housed in the groove portion 38 in a compressed state by reducing the diameter (reducing the diameter). Therefore, the stop ring member 40 acts to increase the diameter (increase the diameter) in this state.

  A packing member 42 is provided at the step portion of the inner wall located on the back side of the joint body 26. Further, the packing member 42 is provided with a ring-shaped hermetic packing 42a and a ring-shaped fireproof packing 42b that is connected to the slide member 30 side. The airtight packing 42a is made of an elastic body such as NBR (nitrile rubber) or fluorine rubber, and the fireproof packing 42b is made of an elastic body integrally formed with, for example, expanded graphite and a rubber material such as NBR. When the flexible tube A is inserted, the exposed metal corrugated tube A1 at the end of the flexible tube A is inserted in close contact with the inner peripheral surface while elastically pressing at least the inner peripheral surface of the packing 42a. It has become. When exposed to high temperatures during a fire or the like, the volume of the fireproof packing 42b expands to seal the inside. In addition, this fireproof packing 42b may not have elasticity, for example, may be C-shaped instead of circular. Furthermore, the position of the fireproof packing 42b may not be continuous with the airtight packing 42a.

  A ring-shaped stopper member 44 is interposed between a side portion on the base end side (left side as viewed in FIG. 1) of the airtight packing 42 a and a step portion on the inner wall of the joint body 26. The stopper member 44 includes a ring portion 46 and a plurality of engagement pieces 48 provided on the inner side thereof at equal intervals along the circumferential direction. The metal corrugated pipe A1 is inserted inside the ring portion 46, and the engagement piece 48 is at a predetermined angle with respect to the axial direction of the ring portion 46 in a direction in which the metal corrugated pipe A1 is inserted. θ, for example, is inclined by 45 degrees, and the inner diameter of the tip is set smaller than the outer diameter of the convex portion 19 of the metal corrugated pipe A1. Therefore, when the metal corrugated pipe A1 reaches the ring-shaped stopper member 44 at the time of insertion, the metal corrugated pipe A1 further abuts against the engaging piece 48 while elastically deforming the engaging piece 48, It will be inserted inside the engagement piece 48.

  In addition, a ring-shaped retainer member 50 is provided between the slide member 30 and the packing member 42. The retainer member 50 is formed integrally with one end of the front collar portion 52 of a cylindrical shape made of, for example, resin, and is inserted into the concave portion 18 of the metal corrugated pipe A1 when the slide member 30 is pushed in. It consists of a metal rear protrusion 54 that engages. Specifically, the inner diameter of the front collar portion 52 is set to be slightly larger than the outer diameter of the convex portion 19 of the metal corrugated pipe A1, so that the metal corrugated pipe A1 is inserted into the front collar section 52. It has become. The plurality of rear protrusions 54 integrated with the front collar portion 52 is slightly larger than the outer diameter of the convex portion 19 of the corrugated pipe A1 and is radially outward when no load is applied before the slide member 30 is pushed. It is in a state where the diameter is increased by inclining so as to open. Each rear projection 54 can be deformed with the ring-shaped front collar 52 as a fulcrum, that is, can be enlarged or reduced in the radial direction.

  Further, a reduced diameter tapered surface 52a is formed in front of the outer surface side of each rear protrusion 54 (on the right side in FIG. 1). When the slide member 30 is pushed in, the diameter-reduced taper surface 52a abuts against a slip-off preventing taper surface 30d provided on the slide member 30 so that each rear protrusion 54 is reduced in diameter, that is, the joint body. 26 is elastically bent and deformed so as to be directed toward the axial center side of 26.

  Note that the end of the slide member 30 that comes into contact with the reduced diameter tapered surface 52a is not limited to the slip-off preventing tapered surface 30d. That is, the end portion of the slide member 30 may have any shape as long as it has a function of reducing the diameter of the retainer member 50 when the retainer member 50 is pressed. The shape of the end portion of the slide member 30 may be a curved surface shape with an appropriate curvature, for example, instead of a tapered surface, or may be an end surface shape stepped so as to have multiple steps. Furthermore, the shape of the end portion of the slide member 30 may be a right-angled end surface obtained by simply cutting off the end portion vertically. As described above, the watertight packing 36, the packing member 42, the retainer member 50, and the stopper member 44 are all installed so as to be in contact with the portion where the predetermined length of the covering is peeled and the metal corrugated pipe A1 is exposed. The layer A3 is not directly electrically connected. Further, since the conductive layer A3 is centered by the watertight packing 36, the conductive layer A3 is not necessarily in contact with the joint body 26 or the slide member 30. As a result, there is a possibility that the electric energy guided by the conductive layer A3 has no place to go and is guided to the metal corrugated tube A1.

  In the pipe joint 1 having the above-described configuration, the flexible pipe A inserted into the inner hole of the joint portion including the joint body 26 and the slide member 30 so as to go around the inner peripheral surface of the slide member 30. A conductor accommodating groove 30c is formed so as to surround the outer periphery. A ring-shaped conductor 20 is inserted into the conductor housing groove 30c. By this conductor 20, the metal layer A3 of the flexible tube A and the slide member 30 are electrically connected.

  Since the slide member 30 is connected to the joint body 26 via the conductive stop ring member 40 as described above, the metal layer A3 of the flexible tube A and the joint body 26 are connected to the conductor 20 and the slide. Electrical conduction is made through the member 30. A connecting male screw 22 is formed at the end of the joint body 26 opposite to the slide member 30 side. The pipe joint 1 is connected to another device (not shown) or a piping member by the connecting male screw 22. These steel pipes or pipe joints are fixed to a steel frame of a building or connected to a buried pipe.

  The conductor 20 will be described in detail. FIG. 2 is a perspective view showing the conductor 20. As shown in FIG. 2, the conductor 20 has a substantially C-shaped ring portion 20a having a notch C in a part of the ring-shaped periphery, and extends from the ring portion 20a toward the axis of the flexible tube A. And a plurality of projecting portions 20b each having a substantially rectangular shape. The conductor 20 is formed from copper or a copper alloy having a thickness of 20 μm to 0.5 mm and has elasticity. The conductor 20 is accommodated in the conductor accommodating groove 30c in a reduced state when the pipe joint 1 is manufactured. Since the conductor 20 (ring portion 20a) tends to expand in diameter due to its elasticity, the outer peripheral surface of the ring portion 20a comes into contact with the bottom surface of the conductor housing groove 30c which is a part of the slide member 30. . Further, the protruding portion 20b of the conductor 20 is inclined toward the inner side of the inner hole of the joint body 26. In addition, the tip portion D of the protruding portion 20b is along the outer peripheral surface of the flexible tube A. It is formed in an arc shape having a moderate curvature. Due to the inclination and elasticity of the protruding portion 20b and the shape of the distal end portion D, the flexible tube A can be smoothly inserted into the inner hole of the pipe joint 1, and the conductor 20 (the protruding portion 20b) is a flexible tube. The metal layer A3 formed on the outer peripheral surface of A is more reliably contacted. The shape of the distal end portion D may be a saw blade shape so as to be easily formed at the time of manufacture while ensuring contact with the outer peripheral surface of the flexible tube A.

  A plurality of protruding portions 20b are provided on the ring portion 20a. For example, as shown in FIG. 3, the metal layer A3 is formed in a strip shape so as to extend in the longitudinal direction at a part of the outer periphery of the flexible tube A. In this case, it is desirable to configure the protrusion 20b so that the protrusion 20b and the strip-shaped metal layer A3 are in contact with each other regardless of the positional relationship during construction of the pipe. The formation of the strip-shaped metal layer A3 is intended to reduce the manufacturing cost of the tube.

  When the metal layer A is thus provided in a strip shape, the flexible tube A between one protrusion 20b of the plurality of protrusions 20b and another protrusion 20b provided adjacent to the protrusion 20b. The circumferential length B2 (FIG. 2) of the protruding portion 20b is such that the circumferential interval B1 (FIG. 2) is smaller than the circumferential length B3 (FIG. 3) of the strip-like conductive layer. 2) is set. In particular, when the metal layer A3 of the flexible tube A extends over the entire outer periphery, only one protrusion 20b may be provided instead of a plurality.

  With the configuration of the pipe joint 1 as described above, the induced lightning surge generated in the flexible pipe A during a lightning strike is sequentially connected via the conductor 20 in the pipe joint 1, the slide member 30, and the joint body 26 (for connection). It can be diffused to other equipment (connected to the male screw 22) or piping members, and further grounded.

  That is, in a general house or the like, when a lightning strike occurs in the vicinity thereof, an induced lightning surge enters a metal part such as a steel frame or an anchor of the building via the ground or an electric wire, and the steel frame and the flexible tube A There is a potential difference between them, which can cause spark discharge. Due to this spark discharge, a hole with a diameter of about 1 mm is opened in the metal corrugated tube A1, and there is a risk of causing gas leakage. According to the pipe joint 1 described above, such an induced lightning surge can be diffused to another steel pipe or the like to cause a ground fault. In particular, since the conductor 20 shown in FIG. 2 is incorporated when the pipe joint 1 is manufactured, a new work other than the connection work between the flexible pipe A and the pipe joint 1 is added at the time of pipe construction. There is no. That is, according to this pipe joint 1, the conductivity to other pipes and the like during lightning strikes is reliably ensured by a simple structure, and the worker of the plumber can improve the conductivity of such pipe joint 1. Without being conscious of the structure involved, the pipe can be constructed in the same manner as usual except that a load is applied to peel off the coating layer A2 of the pipe using a simple tool.

(Second Embodiment)
Next, a pipe joint according to a second embodiment of the present invention will be described. In the present embodiment, a conductor 61 is used instead of the conductor 20 that electrically connects the joint body 26 (slide member 30) and the metal layer A3 of the flexible tube A in the first embodiment. FIG. 4 is a cross-sectional view showing the conductor 61, and FIG. 5 is a perspective view showing the conductor 61. The configurations and operational effects of the pipe joint and conductor other than the configuration and operational effects of the pipe joint and conductor described here are the same as those of the first embodiment.

  As shown in FIGS. 4 and 5, the conductor 61 provided in the pipe joint 1 of the present embodiment includes a ring portion 61 a having a ring shape (or a substantially C shape in which a part of the circumference thereof is notched), and , And a plurality of protruding portions 61b protruding from the ring portion 61a toward the axial center side of the flexible tube A. The ring portion 61a corresponds to the ring 20a, and the protruding portion 61b corresponds to the protruding portion 20b. The conductor 61 is fixed to the side surface of the slide member 30 by screws, brazing using a silver alloy or the like, or a conductive adhesive. Further, the opening end of the slide member 30 protrudes (to the right side in FIG. 4) to form a female screw on the inner peripheral surface thereof, and a short cylindrical holding member having a male screw screwed on the female screw on the outer peripheral surface. The conductor 61 may be pressed by using, for example.

  The shape of the conductor 61 will be described in detail. FIG. 6 is a diagram for explaining the shape of the conductor 61. As shown in FIG. 6A, the protruding portion 61b of the conductor 61 has a bent portion E that bends the tip to the outside of the pipe joint 1, and the protruding portion 61b is formed at the bent portion E. It contacts the metal layer A3 of the flexible tube A.

  Also with such a conductor 61, the side surface of the end portion of the slide member 30 of the joint main body 26 (the side surface of the opening end of the inner hole of the joint main body 26), and the joint portion composed of the joint main body 26 and the slide member 30 The metal layer A3 on the outer peripheral surface of the flexible tube A inserted into the inner hole can be made conductive. If the bent portion E is not provided in the protruding portion 61b as shown in FIG. 6B, the tip portion F may peel off the metal layer A3. Further, since the protruding portion 61b has the bent portion E, when the metal layer A3 is peeled off and the peeled metal layer A3 forms the lump portion G as shown in FIG. In addition, the metal layer A3 of the flexible tube A and the conductor 61 can be made conductive through the massive portion G.

  In addition, according to such a conductor 61, unlike the first embodiment, whether or not the conductor 61 is in contact with the slide member 30 and the metal layer A <b> 3 of the flexible pipe A from the appearance of the pipe joint 1. Can be confirmed. In addition, the conductor 20 of the first embodiment is provided on the inner side (left side in FIG. 4) of the watertight packing 36, whereas the conductor 61 is on the outer side of the watertight packing 36 ( It is provided on the right side of FIG. Therefore, here, the metal layer A3 can be removed to a position outside the water-tight packing 36 and inside the conductor 61. By removing the metal layer A3 in this way, the metal layer A3 can be removed. The watertightness inside the watertight packing 36 can be improved when it is formed in a band shape.

  In addition, this protrusion part 61b has the space | interval according to the length to the outer peripheral direction of the metal layer A3 formed in the strip | belt shape similarly to the protrusion part 20b of the conductor 20 of 1st Embodiment. Good. Thus, the manufacturing cost of the flexible tube A and the conductor 61 can be suppressed by setting an appropriate interval between the plurality of projecting portions 20b.

(Third embodiment)
A pipe joint according to a third embodiment of the present invention will be described. In the present embodiment, a conductor 62 is used in place of the conductor 20 of the first embodiment. FIG. 7 is a sectional view showing the conductor 62, and FIG. 8 is a perspective view showing the conductor 62. The configurations and operational effects of the pipe joint and conductor other than the configuration and operational effects of the pipe joint and conductor described here are the same as those of the first embodiment.

  The slide member 30 has a fixing groove 31 having a rectangular cross section for fixing the conductor 62 on the outer peripheral surface of the end portion thereof. As shown in FIGS. 7 and 8, the conductor 62 includes a ring portion 62 a formed in a ring shape so as to surround the outer periphery of the slide member 30, and a tip side of the ring portion 62 a (on the right side in FIG. 7). A projecting portion 62b projecting from the ring portion 62a toward the axis of the flexible tube A, and a base end side (left side as viewed in FIG. 7) of the ring portion 62a from the ring portion 62a toward the axis of the flexible tube A. And a projecting portion 62 c that is projected and accommodated in the fixing groove 31. The tip of the protruding portion 62b is in contact with the metal layer A3 of the flexible tube A. As shown in FIG. 8, the conductor 62 may be formed by bonding two semicircular arc-shaped ones using screws or an adhesive or the like. But you can. In the case where the conductor 62 is formed integrally, the conductor 62 is given an appropriate elasticity in order to fit the protruding portion 62c into the fixing groove 31.

  The conductor 62 is also inserted into the outer peripheral surface of the end of the slide member 30 of the joint body 26 (the outer peripheral surface of the opening end of the inner hole of the joint main body 26) and the inner hole of the joint main body 26. The metal layer A3 on the outer peripheral surface of the flexible tube A can be made conductive. Furthermore, like the second embodiment, the conductor 62 improves the visibility of the contact portion from the appearance as compared with the first embodiment, and improves the water tightness inside the pipe joint 1. Can do. In addition, the conductor 62 comes into contact with the metal layer A3 more firmly and stably than the conductor 61 of the second embodiment because of its structure.

(Other embodiments, etc.)
As mentioned above, although this invention was demonstrated by specific embodiment, this invention is not limited to the said embodiment, It can change and implement in the range which does not deviate from the summary of this invention. For example, in the first embodiment, the ring portion 20a and the protruding portion 20b of the conductor 20 in FIG. 2 are obtained by cutting a piece of metal into a predetermined shape and then bending the cut piece. It was assumed that it was produced by applying. On the other hand, in order to improve the installation stability of the ring portion 20a on the slide member 30, the conductor 20 needs to have a certain thickness. However, when the conductor 20 is thickened, the protrusion 20b is also thickened, which may increase resistance when the flexible pipe A is inserted into the inner hole of the joint body 26. In order to make the insertion resistance of the flexible tube A appropriate, the thickness of the ring portion 20a and the protruding portion 20b is formed to different thicknesses by adding a pressing process to the protruding portion 20 in the production of the conductor 20. May be.

  Moreover, the following modifications can be employed in the first embodiment. FIG. 9 is a cross-sectional view showing the conductor 20 in one modification of the pipe joint of the first embodiment. This embodiment is different from the first embodiment in that a pressing plate for stabilizing the installation of the conductor 20 is used. That is, the pressing plate 20d has a short cylindrical shape or a C-shaped shape with a part of the short cylinder cut out, and the pressing plate 20d is provided along the inner peripheral surface of the ring portion 20a. Alternatively, the presser plate 20d may be elastic so that the presser plate 20d expands and contracts, and the presser plate 20d may be biased toward the outer peripheral side of the flexible tube A by its elasticity. When the flexible pipe A is inserted into the inner hole of the pipe joint 1, the pressing plate 20d has an appropriate resistance. By using the holding plate 20d, the flexible tube A can be inserted more smoothly, and the installation state of the conductor 20 in the conductor housing groove 30c can be further stabilized.

  In the first embodiment and its modifications, the shape of the ring portion 20a of the conductor 20 is a thin plate as shown in FIGS. Instead of this, for example, a wire may be used for the conductor 20, or a rectangular cross section may be used. Alternatively, the conductor 20 may be a spirally wound linear body. That is, the conductor 20 only needs to have a shape in which the joint body 26 or the slide member 30 and the metal layer A3 of the flexible pipe A come into contact when the flexible pipe A is inserted into the joint body 26 of the pipe joint 1. The material of the conductor 20 is not limited to a single metal. As long as the conductor 20 is a conductive member, for example, a conductive paint may be applied on a resin member. Of course, the lower the electrical resistance value, the better the performance of the conductor 20.

  FIG. 10 is a cross-sectional view showing the conductor 20 in another modification of the pipe joint of the first embodiment. This embodiment is different from the first embodiment in that an auxiliary elastic member 20e for making the protruding portion 20b of the conductor 20 more reliably contact the metal layer A3 of the flexible tube A is used. That is, the auxiliary elastic member 20e has a ring shape (or a C shape with a part thereof cut out), and the auxiliary elastic member 20e is formed on the inner peripheral surface of the ring portion 20a and the inner surface of the protruding portion 20b. It is provided along. For example, when the flexible tube A is flattened or inserted in an oblique direction when the flexible tube A is inserted, the protruding portion 20b hitting the flexible tube A may fall more than necessary. By using the auxiliary elastic member 20e, it is possible to prevent the collapse and prevent the metal layer A3 of the flexible tube A and the conductor 20 to come into contact with each other. As a result, the electrical conductivity between the metal layer A3 of the flexible tube A and the slide member 30 is more reliably ensured.

  Here, it is assumed that a rubber material is used for the auxiliary elastic member 20e. However, the auxiliary elastic member 20e is limited to a rubber material as long as it has a force to push the protruding portion 20b, which is a thin metal piece, substantially toward the axis. It is not a thing. In addition to the function of improving the contact between the conductor 20 and the metal layer A3 of the flexible tube A, the auxiliary elastic member 20e can be more stably installed with the conductor 20 similar to the pressing plate d. It is also possible to provide a function for

  Without using such an auxiliary elastic member 20e, the collapse of the protrusion 20b during the insertion of the flexible tube A described above is prevented, and the contact between the conductor 20 and the metal layer A3 of the flexible tube A is improved. Therefore, a material having excellent elasticity such as spring steel may be used as the material of the protruding portion 20b.

  Furthermore, in the second embodiment, an auxiliary elastic member 61c similar to the auxiliary elastic member 20e described above may be provided as shown in FIG. The auxiliary elastic member 61c is made of rubber or metal and has elasticity. The auxiliary elastic member 61c has a ring shape (or a C shape with a part cut away). The auxiliary elastic member 61c acts to reduce the diameter, that is, to press the tip of the bent portion G against the metal layer A3 of the flexible tube A. By using such an auxiliary elastic member 61c, the position of the bent portion G of the conductor 61 of the protruding portion 61b can be stabilized, and the conductor 61 and the metal layer A3 of the flexible tube A can be reliably brought into contact with each other. become.

  Also in the third embodiment, as shown in FIG. 11B, an auxiliary elastic member 62d similar to the auxiliary elastic member 61c described above can be used. With this auxiliary elastic member 62d, the position of the conductor 62 can be stabilized, and the contact between the conductor 62 and the metal layer A3 of the flexible tube A can be enhanced.

  In each of the above embodiments, the joint portion having an inner hole into which the end portion of the pipe is inserted and having conductivity is composed of the joint body 26, the slide member 30, and the like. Unlike this, for example, the present invention can be applied to a pipe joint that does not use a slide member. That is, in this case, the joint body itself constitutes a joint portion having the above-mentioned inner hole, and the conductive layer of the pipe inserted into the inner hole of the joint body and the joint body are within the inner hole. Conduction is performed by a conductor provided at the opening end of the peripheral surface or the inner hole.

It is sectional drawing which shows the pipe joint 1 for flexible pipes of 1st Embodiment. 3 is a perspective view showing a conductor 20 of the pipe joint 1. FIG. It is a perspective view which shows the flexible pipe | tube which has a strip | belt-shaped conductive layer used conventionally. It is sectional drawing which shows the conductor 61 of the pipe joint of 2nd Embodiment. It is a perspective view which shows the conductor 61. FIG. It is a figure for demonstrating the shape of the conductor 61. FIG. It is sectional drawing which shows the conductor 62 of the pipe joint of 3rd Embodiment. 4 is a perspective view showing a conductor 62. FIG. It is sectional drawing which shows the conductor 20 in one modification of the pipe joint 1 of 1st Embodiment. It is sectional drawing which shows the conductor 20 in the other another modification of the pipe joint 1 of 1st Embodiment. It is a figure for demonstrating the auxiliary | assistant elastic member in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pipe joint 20, 61, 62 ... Conductor 20a, 61a, 62a ... Ring part 20b, 61b, 62b ... Protrusion part 26 ... Joint main body 30 ... Slide member A ... Flexible pipe A1 ... Metal corrugated pipe A3 ... Metal layer

Claims (8)

A pipe joint used for connecting a pipe having a conductive layer to the outer peripheral surface,
A joint portion having an inner hole into which an end of the tube is inserted and having conductivity;
A pipe joint comprising a conductor that is provided so as to surround an outer periphery of the pipe inserted into the inner hole and conducts between the conductive layer of the pipe and the joint portion.   2. The pipe joint according to claim 1, wherein a shape of the conductor is a ring shape surrounding an outer periphery of the pipe inserted into an inner hole of the joint portion.   The pipe joint according to claim 2, wherein the conductor has a notch in a part of a ring-shaped circumference.   The said conductor is arrange | positioned so that both the internal peripheral surface of the inner hole of the said joint part and the conductive layer of the said pipe | tube inserted in the said inner hole may be contacted. The pipe joint according to claim 3.   The said conductor is arrange | positioned so that both the opening edge part of the inner hole of the said joint part and the conductive layer of the said pipe | tube inserted in the said inner hole may be contacted. The pipe joint according to claim 3.   The pipe joint according to any one of claims 2 to 5, wherein the conductor has a plurality of protrusions protruding toward the axial center side of the conductor. The conductive layer of the tube is formed in a band shape so as to extend in the longitudinal direction of the tube at a part of the outer periphery of the tube,
The interval in the circumferential direction of the tube between one projection of the plurality of projections and another projection adjacent to the one projection is in the circumferential direction of the tube in the conductive layer. The pipe joint according to claim 6, wherein the pipe joint is smaller than the length of the pipe joint. An overvoltage protection method for a pipe that protects the pipe from overvoltage by a pipe joint having an inner hole through which an end portion of a pipe having a conductive layer is inserted on the outer peripheral surface and having a conductive joint portion.
An overvoltage protection method for a tube, wherein a conductive body provided so as to surround an outer periphery of the tube inserted into the inner hole is electrically connected between the conductive layer of the tube and the joint portion.

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