JPH0736545U - Cable gland - Google Patents

Abstract

(57) [Summary] [Purpose] To increase the connection strength of the armored cable 10 to the cable gland. A grounding metal 70 for electrically connecting the steel pipe 12 of the armored cable 10 and the main body 30 of the cable gland is a ring body in which at least a tip portion is circumferentially divided. Bend the tip of each divided piece inward.
A tapered surface 38 is provided on the inner surface of the joint body 30. By screwing the cap nut 90, the grounding metal 70 is pushed into the tapered surface 38, and the tip of each divided piece is cut into the outer surface of the steel pipe 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cable ground used for attaching armored cables to equipment.

[0002]

[Prior art]

 As shown in FIG. 1, the armored cable is a cable in which an extension cable 11 is doubly covered with a steel pipe 12 and a rubber pipe 13, and is used for electric wiring in a factory or the like. The steel pipe 12 is a corrugated pipe in order to have flexibility, and for this reason, this cable is also called a corrugated steel pipe armored cable.

When such an armored cable 10 is attached to a device, not only mechanically connecting the armored cable 10 to the attachment target but also electrically connecting the steel pipe 12 of the armored cable 10 to the attachment target. Is required. The joint that does this is a cable gland, and if it is an explosion-proof type, it is required to further increase the connection strength by connecting the extension cable 11 to the cable gland.

FIG. 1 shows a conventional example of an explosion-proof cable gland used for connecting armored cables. This cable gland is provided with a cylindrical main body 1 whose tip is screwed into an attachment target portion. The inner surface of the rear portion of the main body 1 has a diameter larger than that of the inner surface on the front end side to form a housing portion, and the elastic ring 2 is inserted therein. A pressing ring 3 and a waterproof ring 4 are arranged on the rear end side of the elastic ring 2. The inner surface of the rear portion of the pressing ring 3 is a tapered surface whose diameter gradually increases toward the rear end side. A tip portion of the waterproof ring 4 is a taper portion that fits inside the tapered surface, and a plurality of conductive chips 5 are held at the tip portion with a circumferential gap. A retaining ring 6 is fitted onto the rear portion of the waterproof ring 4, and a cap nut 7 is screwed onto the outer surface of the rear portion of the main body 1 so as to press the retaining ring 6 toward the tip side.

The extension cable 11 of the armored cable 10 is inserted through the elastic ring 2. The steel pipe 12 is located inside the tapered portion of the waterproof ring 4, and the rubber pipe 13 is located inside the rear portion of the waterproof ring 4.

When the cap nut 7 is screwed into the main body 1 from the rear end side, the holding ring 6 is pushed toward the front end side. As a result, the rear portion of the waterproof ring 6 is compressed in the axial direction and comes into pressure contact with the rubber tube 13 of the armored cable 10. As a result, the armored cable 10 is waterproofly connected to the cable gland. At the same time, the tip portion of the waterproof ring 6, that is, the taper portion is pushed into the inside of the tapered surface of the pressing ring 3 to reduce its diameter, so that the pressing ring 3 and the steel pipe 12 are electrically connected via the plurality of conductive tips 5. Connected. Further, the pushing force of the waterproof ring 6 is transmitted to the elastic ring 2 via the pressing ring 3 and compresses it in the axial direction. As a result, the elastic ring 2 is pressed against the extension cable 11, and the extension cable 11 is held.

Other screw-type explosion-proof cable glands have been proposed, but both have the same mechanism for mechanically and electrically connecting armored cables.

[0008]

[Problems to be solved by the device]

 Since such an explosion-proof cable gland is a screw type, it is easy to operate, and the above-mentioned requirements are met for the time being. However, if a large pulling force is applied to the connected armored cable 10, the armored cable 10 may come off from the cable gland. Even if the steel pipe 12 of the armored cable 10 is not completely removed, if the steel pipe 12 of the armored cable 10 moves from the conductive tip 5 to the rear end side, a ground failure occurs. Therefore, the reliability is low.

The first reason that the armored cable 10 is likely to come off from the ground joint is that the plurality of conductive tips 5 and the steel pipe 12 are made of metal and therefore slippery. The second reason is that the screwing force by the cap nut 7 is transmitted to the elastic ring 2 via the waterproof ring 6 which is an elastic material, so that the elastic ring 2 is not compressed sufficiently and the holding strength of the extension cable 11 is lowered. There is a danger. It goes without saying that this leads to a decline in the function of the explosion-proof type.

The present invention was created in view of such circumstances, and an object thereof is to provide a cable gland that is easy to operate and has high connection strength.

[0011]

[Means for Solving the Problems]

 The cable gland according to claim 1 is a normal waterproof connection type, the tip portion of which is screwed into a mounting object, the extension cable of the armored cable is inserted through the inside, and the rear end is provided on the inner surface of the rear portion. A cylindrical main body with a tapered surface that gradually expands in diameter toward the inside, and a main body of the armored cable that is inserted from the rear end inside the tapered surface of the main body and at least the front end Is divided into a plurality of parts in the circumferential direction, each of which has a ring-shaped grounding fitting with its inside bent in a hook shape, and the rubber tube of the armored cable is inserted inside the grounding fitting at the rear end side of the grounding fitting. And a cap nut screwed onto the outer surface of the main body to press the waterproof ring toward the tip side.

The cable gland according to claim 2 is an explosion-proof type, the tip portion of which is screwed into a mounting object, the extension cable of the armored cable is inserted through the inside, and the rear inner surface expands from the inner surface on the tip side. A cylindrical body that is diametrically formed to form a housing portion; an elastic ring that is inserted into the housing portion of the body; and a cap nut that is screwed onto the outer surface of the body to press the elastic ring toward the tip side. An intermediate ring, in which a taper surface that gradually expands in diameter toward the rear end side is provided on the inner surface on the rear end side of the pressing surface, and the intermediate ring is inserted from the rear end side inside the tapered surface, and the inside of the armored cable is inserted inside. The steel pipe is inserted, and at least the tip is divided into multiple pieces in the circumferential direction, and the tip of each of them is a ring-shaped grounding fitting that is bent inwardly in a hook shape, and there is a rear end side of the grounding fitting. Comprising a waterproof ring rubber tube armored cable inside is inserted and a cap nut which is screwed on the outer surface of the intermediate ring so as to press the waterproof ring distally

[0013]

[Action]

 In the cable gland according to the first aspect, by screwing the cap nut into the main body, the waterproof ring is pressed toward the distal end side and compressed in the axial direction, so that the rubber ring of the armored cable is pressed against the rubber tube. As a result, the armored cable is waterproofly connected to the cable gland. At the same time, the ground metal is pushed into the tapered surface of the inner surface of the main body and the diameter is reduced from the tip. The tip of the grounded metal object is divided into multiple parts in the circumferential direction, and each tip is bent inward, so that each tip bites into the outer surface of the steel pipe of the armored cable. Therefore, the main body and the steel pipe are electrically connected to each other through the grounding metal object, and at the same time, the steel pipe is prevented from coming off. Therefore, the connection strength of the armored cable is increased.

In the cable gland according to the second aspect of the present invention, by screwing the intermediate ring formed of the cap nut into the main body, the elastic ring housed in the main body is pressed toward the tip side and compressed in the axial direction. This presses against the extension cable of the armored cable, and the extension cable is connected to the cable gland. Since the screwing force of the intermediate ring is directly applied to the elastic ring, the connection strength of the extension cable is high.

By screwing the cap nut into the intermediate ring, the waterproof ring is pressed toward the distal end side and compressed in the axial direction, so that the rubber ring of the armored cable is pressed against the rubber ring. This waterproofly connects the armored cable to the ground joint. At the same time, the ground metal is pushed inside the tapered surface of the inner surface of the intermediate ring and contracts from the tip. The tip of the grounding metal is divided into multiple parts in the circumferential direction, and each tip bends inwardly in a hook shape, so that each tip bites into the steel pipe outer surface of the armored cable. Therefore, the main body and the steel pipe are electrically connected to each other through the ground metal, and at the same time, the steel pipe is prevented from coming off.

[0016]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a half sectional view of a cable gland showing an embodiment of the present invention, FIG. 3 is a half sectional view showing the components of the cable gland separately, and FIG. 4 is a half sectional view and a front view of a grounding metal object. is there.

This embodiment is an explosion-proof type and is an example of the cable gland described in claim 2. As shown in FIGS. 2 and 3, the cable gland includes a cylindrical main body 30 directly attached to the attachment target 20, a cylindrical elastic ring 40 inserted into the main body 30 from the rear end side, and a pressing member. The ring 50, an intermediate ring 60 that is screwed into the main body 30 from the rear end side and presses the elastic ring 40 and the pressing ring 50 toward the front end side, a grounding metal object 70 that is inserted into the intermediate ring 60 from the rear end side, and a waterproof member. A ring 80 and a cap nut 90 that is screwed into the intermediate ring 60 from the rear end side and presses the ground metal fitting 70 and the waterproof ring 80 toward the front end side are provided.

The main body 30 has a male screw portion 31 screwed into the screw hole 21 of the attachment target 20 on the outer surface of the front end portion. On the outer surface on the rear end side of the male screw portion 31, there are sequentially provided a polygonal portion 32 with which a screwing tool is engaged, a second male screw portion 33 for screwing the intermediate ring 60, and a flat portion. An O-ring 36, which seals between the main body 30 and the intermediate ring 60, is attached.

The extension cable 11 of the armored cable 10 is inserted into the main body 30. The rear inner surface of the main body 30 has a diameter larger than that of the front inner surface to form a housing portion 37.

The elastic ring 40 is made of rubber and is inserted into the housing portion 37 of the main body 30 while being sandwiched between the two washers 41, 41. The outer diameter of the elastic ring 40 is slightly smaller than the inner diameter of the housing portion 37, and the inner diameter is slightly larger than the outer diameter of the extension cable 11.

The pressing ring 50 has substantially the same inner and outer diameters as the elastic ring 40 except for the rear end portion, is inserted into the accommodating portion 37 of the main body 30 from the rear end side, and is located outside the extension cable 11. The rear end of the pressing ring 50 is slightly larger in inner and outer diameters than the other parts.

The intermediate ring 60 is composed of a cap nut having a pressing surface 61 perpendicular to the central axis at the center of the inner surface. A female screw portion 64 that is screwed into the second male screw portion 33 of the main body 30 is provided on the inner surface on the tip side of the pressing surface 61. A first taper surface 62 and a second taper surface 63 are provided on the inner surface on the rear end side of the pressing surface 61 in two steps from the front end side to the rear end side with a slight flat portion interposed therebetween. Each of the tapered surfaces 62 and 63 gradually increases in diameter from the front end side to the rear end side and opens to the rear end side. On the outer surface of the rear end portion of the intermediate ring 60, a male screw portion 65 with which a female screw portion of the cap nut 90 is screwed is provided.

The extension cable 11 of the armored cable 10 is inserted into the tip end side of the pressing surface 61 of the intermediate ring 60, and the steel pipe 12 is inserted into the rear end side thereof.

As shown in FIG. 4, the grounding hardware 70 is a sleeve made of a conductive metal, and a plurality of grounding pieces formed by dividing the sleeve in the circumferential direction except the rear end portion thereof. 71 are arranged at equal intervals in the circumferential direction. Each grounding piece 71 is slightly inclined inward as a whole, and its tip is bent inwardly in a hook shape. The grounding metal 70 is connected to the tip of the waterproof ring 80, is inserted from the rear end side into the first tapered surface 62 of the intermediate ring 60, and is located outside the steel pipe 12 of the armored cable 10.

The waterproof ring 80 is a sleeve made of rubber, and an annular groove into which a rear end of the waterproof ring 80 is fitted is provided on a front end surface of the waterproof ring 80 in order to hold the ground metal fitting 70. The outer surface of the tip portion of the waterproof ring 80 is a taper surface 82 corresponding to the second tapered surface 63 of the intermediate ring 60.

The rubber tube 13 of the armored cable 10 is inserted into the waterproof ring 80 from the rear end side. On the outer surface of the waterproof ring 80 excluding the tapered surface 82, a shallow V groove is provided over the entire circumference in order to ensure the holding of the rubber tube 13.

The cap nut 90 is externally fitted to the waterproof ring 80, and is screwed onto the outer surface of the rear end portion of the intermediate ring 60 in order to press the waterproof ring 80 toward the front end side.

The usage method and function of the explosion-proof cable gland of this embodiment are as follows.

The male screw portion 31 of the main body 30 is screwed into the screw hole 21 of the attachment object 20 and fixed by the lock nut 35. The cap nut 90, the ground metal 70, the waterproof ring 80, the intermediate ring 60, the retaining ring 50, the elastic ring 40, and the washers 41, 41 are sequentially fitted onto the extension cable 11 of the armored cable 10 from the front end side, and the extension cable 11 Thread 11 through body 30.

The rubber tube 13 of the armored cable 10 is inserted into the waterproof ring 80, and the steel tube 12 is positioned inside the ground metal fitting 70, and the ground metal fitting 70 and the waterproof ring 80 are inserted into the intermediate ring 60. The cap nut 90 is screwed into the outer surface of the rear end of the intermediate ring 60. By this screwing, the waterproof ring 80 is compressed in the axial direction, and the tip end thereof is pushed into the second tapered surface 63 of the intermediate ring 60 to reduce its diameter, so that the rubber tube 13 is waterproof to the intermediate ring 60. Connected.

At the same time, the ground metal piece 70 is pushed into the first tapered surface 62 of the intermediate ring 60, and the plurality of ground pieces 71 are inclined inward. As a result, the tip of the hook portion of each grounding piece 71 bites into the outer surface of the steel pipe 12 of the armored cable 10, and the steel pipe 12 and the intermediate ring 60 are electrically connected via the plurality of grounding pieces 71, and 12 is mechanically retained. Therefore, even if a large pulling force is applied to the connected armored cable 10, the armored cable 10 does not come off.

In this embodiment, since the grounding metal fitting 70 is connected to the tip of the waterproof ring 80, it is easy to set it. The grounding hardware 70 can also be connected by integral molding with the waterproof ring 80.

The elastic ring 40 is inserted into the housing portion 37 of the main body 30 while being sandwiched between the washers 41, 41, and the pressing ring 50 is inserted from the rear thereof. The tip portion of the intermediate ring 60 is screwed into the second male screw portion 33 of the main body 30. By this screwing, the pressing ring 50 is pushed toward the tip side by the pressing surface 61 of the intermediate ring 60, and the elastic ring 40 is axially compressed in the housing portion 37. As a result, the extension cable 11 of the armored cable 10 is fixed in the main body 30.

At this time, the screwing force of the intermediate ring 60 is directly transmitted to the elastic ring 40 via the pressing ring 50. Therefore, the elastic ring 40 is sufficiently compressed and the extension cable 11 of the armored cable 10 is securely fixed. In this embodiment, since the pressing ring 50 is used, a sufficient screwing stroke can be secured. Further, the O-ring 36 seals between the main body 30 and the intermediate ring 60.

Although screwing of the intermediate ring 60 and screwing of the cap nut 90 may be performed by using a gullet first, the screwing of the intermediate ring 60 moves the intermediate ring 60 to the tip side of the armored cable 10. If the intermediate ring 60 is screwed in first, there is a possibility that the ground metal fitting 70 may come off from the inside of the tapered surface 62 of the intermediate ring 60. Therefore, the cap nut 90 is usually screwed in first.

FIG. 5 is a half sectional view showing another embodiment of the present invention. Since this embodiment is a normal waterproof connection type cable gland, the cap nut 90 is directly screwed into the main body 30 without using the elastic ring 40, the pressing ring 50 and the intermediate ring 60. Further, on the inner surface of the rear portion of the main body 30, taper surfaces 38, 39 corresponding to the taper surfaces 62, 63 of the intermediate ring 60 are provided instead of the housing portion 37. Moreover, packing is interposed between the attachment target 20 and the main body 30. The other structure is the same as that of the above embodiment.

In this embodiment, by screwing the cap nut 90, the waterproof ring 80 is axially compressed, and the tip of the waterproof ring 80 is pushed into the second tapered surface 39 of the main body 30 to reduce the diameter. Then, the rubber tube 13 is waterproofly connected to the main body 30. At the same time, the ground metal piece 70 is pushed into the first tapered surface 38 of the main body 30 and the plurality of ground pieces 71 1 are inclined inward. As a result, the tip of the hook portion of each grounding piece 71 bites into the outer surface of the steel pipe 12 of the armored cable 10, the steel pipe 12 and the main body 30 are electrically connected through the plurality of grounding pieces 71, and the steel pipe 12 is mechanically connected. Will be retained. Therefore, sufficient connection strength can be obtained as a waterproof connection type.

[0038]

[Effect of device]

 As explained above, the cable gland according to the present invention uses at least a plurality of circumferentially divided tip portions, and each tip portion uses a grounding metal that is bent like a hook inward, and the grounding is performed by screwing a cap nut. The diameter of the end of the metal object is reduced so that the tip of the hook part bites into the outer surface of the steel pipe of the armored cable, so even if a large pulling force is applied to the connected armored cable, the armored cable is difficult to pull out. Therefore, the grounding becomes reliable and the reliability is high.

The cable gland according to claim 2 further presses the elastic ring, which comes into pressure contact with the extension cable of the armored cable, toward the tip side by screwing in an intermediate ring different from the cap nut, so that the screwing force is increased. Since it is directly attached to the elastic ring, the connection strength of the extension cable is also high. Therefore, excellent connection strength can be obtained as an explosion-proof type.

[Brief description of drawings]

FIG. 1 is a half cross-sectional view showing the configuration of a conventional explosion-proof cable gland.

FIG. 2 is a half sectional view of an explosion-proof cable gland showing an embodiment of the present invention.

FIG. 3 is a half sectional view showing the constituent members of the ground joint separately.

4A and 4B are a half sectional view and a front view showing a grounding metal object of the grounding joint.

FIG. 5 is a half sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 10 Armored Cable 11 Extension Cable 12 Steel Pipe 13 Rubber Pipe 20 Object to be Attached 30 Main Body 37 Accommodating Section 38, 39 Tapered Surface 40 Elastic Ring 50 Holding Ring 60 Intermediate Ring 62, 63 Tapered Surface 70 Grounding Metal 71 Grounding Piece 80 Waterproof Ring 90 Bag nut

Claims (5)

[Scope of utility model registration request] 1. A cable gland for mechanically connecting an armored cable in which an extension cable is doubly covered with a steel pipe and a rubber pipe to a mounting object, and electrically connecting the steel pipe to the mounting object. A distal end is screwed into the object to be attached, the extension cable is inserted through the inside, and a cylindrical main body in which a taper surface whose diameter gradually increases toward the rear end is provided on the rear inner surface, and a main body of the main body. Inserted from the rear end side inside the tapered surface, while the steel pipe is inserted inside, at least the tip part is divided into a plurality of parts in the circumferential direction, and each tip part is a ring-shaped grounding fitting bent inward in a hook shape. A waterproof ring at the rear end side of the grounding fitting, into which the rubber tube is inserted, and a cap nut screwed onto the outer surface of the main body to press the waterproof ring toward the distal end side. Cable gland which is characterized the door. 2. A cable gland for mechanically connecting an armored cable in which an extension cable is doubly covered with a steel pipe and a rubber pipe to a mounting object, and electrically connecting the steel pipe to the mounting object. A distal end is screwed into the attachment object, the extension cable is inserted through the inside, and a rear inner surface is formed to have a diameter larger than that of the inner surface on the distal end side to form a housing portion. It consists of an elastic ring to be inserted and a cap nut screwed into the outer surface of the main body to press the elastic ring toward the tip side, and the diameter gradually increases toward the rear end side on the inner surface on the rear end side from the pressing surface. An intermediate ring provided with a tapered surface, and the intermediate ring is inserted inside the tapered surface from the rear end side, the steel pipe is inserted therein, and at least the tip is divided into a plurality in the circumferential direction. A ring-shaped grounding fitting whose tip is bent inwardly in a hook shape, a waterproof ring at the rear end of the grounding fitting into which the rubber tube is inserted, and the waterproof ring is pressed to the tip side. Explosion-proof cable gland, comprising: a cap nut screwed onto the outer surface of the intermediate ring. 3. The cable gland according to claim 1, wherein the grounding metal is connected to a tip of a waterproof ring. 4. The explosion-proof cable gland according to claim 2, wherein a pressing ring that moves toward the front end side by screwing the intermediate ring is arranged on the rear end side of the elastic ring. 5. The explosion-proof cable gland according to claim 2, wherein a seal ring is interposed between the outer surface of the rear end of the main body and the inner surface of the front end of the intermediate ring.