JP7649670B2 - Mounting member to be mounted on the tip of a power cable, and method for pulling a power cable using said mounting member - Google Patents

Description

The present invention relates to an attachment member that is attached to the tip of a power cable, and a method for towing a power cable using the attachment member.

Conventionally, when laying a power cable or removing an existing power cable, a tool (attachment member) called a pulling eye is known that is attached to the terminal of the power cable. By pulling the pulling eye attached to the power cable with a pulling device, the power cable can be pulled into a pipeline or the like, and easily moved to a connection location where the target device to which the power cable is to be connected is installed.

A method is generally known in which the pulling eye is compressed and connected to the cable conductor exposed at the terminal of the power cable. Patent Document 1 also discloses a method of connecting the pulling eye and the optical cable by applying an adhesive between the tip of the optical cable and the inner surface of the insertion hole in the pulling eye, and applying a waterproof compound to the tip of the optical cable.

JP 2000-2827 A

However, when moving a power cable by pulling it with a pulling eye, if the installed line is long and multiple pulling operations are required, the operation takes a long time. Specifically, the process of stripping the sheath of the power cable to expose the cable conductor, the process of attaching the pulling eye, and the process of cutting the cable after pulling are repeated.

Of these processes, the process of attaching the pulling eye, i.e., compressing and connecting the attachment part (attachment part) of the pulling eye to the cable conductor, takes the most time, so from the perspective of improving the efficiency of the above work, it was desirable to simplify the process of attaching the pulling eye to the power cable.

The object of the present invention is to provide an attachment member that is attached to the tip of a power cable, which simplifies the process of attaching an attachment part to a power cable and thereby makes it possible to improve the efficiency of the power cable pulling operation, and a method of pulling a power cable using the attachment member.

The attachment member to be attached to the tip of the power cable according to the present invention comprises:
An attachment member that is attached to a tip portion of a power cable when the power cable is towed,
an attachment portion having an insertion hole into which the tip portion is inserted, a traction portion being provided at one end side of the insertion hole in the extending direction, and an opening at the other end side of the insertion hole in the extending direction to allow the tip portion to be inserted into the insertion hole;
The inner surface of the mounting portion surrounding the internal space of the insertion hole is
An adhesive applying section is provided to apply an adhesive for adhering the tip section,
The adhesive applying portion has a recessed portion recessed outward so that the adhesive applied to the adhesive applying portion can accumulate,
The mounting portion has a through hole that penetrates from an outer surface of the mounting portion toward the insertion hole .

A method for pulling the power cable using the mounting member according to the present invention includes the steps of:
a mounting part having an insertion hole into which a tip end of a power cable is inserted, a pulling part being provided at one end side in an extension direction of the insertion hole, and an opening at the other end side in the extension direction of the insertion hole so that the tip end can be inserted into the insertion hole, the mounting part having a through hole penetrating from an outer surface of the mounting part toward the insertion hole, an inner surface of the mounting part surrounding an internal space of the insertion hole constitutes an adhesive application part where an adhesive for adhering the tip end is applied, and a mounting member having a recessed portion recessed outward so that the adhesive applied to the adhesive application part can accumulate,
an insertion step of inserting the tip portion into the insertion hole; and an application step of applying the adhesive between the tip portion and the inner surface through the through hole after the insertion step, and an adhesion step of adhering the tip portion to the mounting portion;
a pulling step of pulling the power cable by the pulling part via the mounting part after the bonding step;
has.

The present invention simplifies the process of attaching the attachment part to the power cable, and thus improves the efficiency of the power cable pulling operation.

FIG. 2 is a half cross-sectional view showing a pulling eye having an attachment portion according to an embodiment of the present invention. FIG. 11 is a half cross-sectional view showing a pulling eye in a state where an insertion hole of the mounting portion is filled with adhesive. FIG. 11 is a half cross-sectional view showing a pulling eye into which a cable conductor having a recess is inserted. FIG. 13 is a half cross-sectional view showing a modified pulling eye having a spacer. FIG. 13 is a half sectional view showing a modified pulling eye having a wedge member.

The following describes in detail an embodiment of the present invention with reference to the drawings. Figure 1 is a half cross-sectional view showing a pulling eye 1 having an attachment part according to an embodiment of the present invention.

As shown in FIG. 1, the pulling eye 1 is an attachment member for pulling the power cable 2, and has a connecting part 10 and an attachment part 20. The connecting part 10 is a pulling part that is connected to a pulling device (not shown), such as an eye nut, that pulls the power cable 2 to a connection location, and is connected to the attachment part 20.

The mounting part 20 is a part that is mounted to the power cable 2. The mounting part 20 extends in a predetermined direction and is configured as a tube with a bottom. The predetermined direction is the direction that becomes the pulling direction when the power cable 2 is pulled. The mounting part 20 has an insertion hole 21. The insertion hole 21 opens at the end opposite the connection part with the coupling part 10 (the other end side in the extending direction of the insertion hole 21). The insertion hole 21 extends in a predetermined direction to the bottom located on the connection part side with the coupling part 10 (one end side in the extending direction of the insertion hole 21), and the cable conductor 3 (tip part) of the power cable 2 is inserted into it.

The diameter of the insertion hole 21 is larger than the diameter of the cable conductor 3, so that when the cable conductor 3 is inserted into the insertion hole 21, a small gap is created between the inner surface 21A, which is the inner peripheral surface of the mounting portion 20 that surrounds the internal space of the insertion hole 21, and the cable conductor 3. The gap between the inner surface 21A and the cable conductor 3 is extremely small so that other members cannot enter. Note that in Figure 1 and other figures, the gap between the inner surface 21A and the cable conductor 3 is shown large in consideration of ease of viewing the drawing.

An adhesive for adhering the cable conductor 3 is applied to the inner surface 21A of the attachment portion 20. In other words, the inner surface 21A of the attachment portion 20 constitutes an adhesive application portion where adhesive for adhering the tip end of the power cable 2 is applied.

The length of the gap between the inner surface 21A of the mounting portion 20 and the cable conductor 3 can be set appropriately depending on the type of adhesive.

The inner surface 21A of the mounting portion 20 has a recess 21B that is recessed on the opposite side to the internal space of the insertion hole 21, i.e., on the outside. Specifically, a plurality of recesses 21B are provided in the extension direction of the insertion hole 21, and are provided all over the inner surface 21A in the circumferential direction. In other words, the inner surface 21A of the insertion hole 21 has, for example, a threaded shape. Note that the recesses 21B are not limited to this, and may be formed, for example, by a coarse cutting bit.

By providing the recess 21B in this manner, as shown in FIG. 2, the adhesive G applied to the inner surface 21A (adhesive application portion) of the insertion hole 21 is allowed to accumulate in the recess 21B.

This allows the anchor effect based on the shear force of the adhesive G accumulated in the recess 21B to increase the adhesive strength between the mounting part 20 and the power cable 2 while stabilizing the tensile force of the power cable 2.

Specifically, when the cable conductor 3 and the attachment portion 20 are bonded with the adhesive G and the pulling eye 1 is pulled, a reaction force T (N) is generated as a tension in the cable conductor 3. This reaction force T depends on the shear strength P (N/mm ² ) of the adhesive G.

The total tension acting on the pulling eye 1 is the sum of the repulsive force T of the adhesive G that spreads in a planar manner between the surface and inner surface 21A of the cable conductor 3, and the shear stress t1 of the adhesive G that has entered and accumulated in the recess 21B so as to have a thickness in the radial direction, which is a direction intersecting the pulling direction. This makes it possible to stabilize the pulling force of the power cable 2 in the pulling direction while increasing the adhesive strength between the attachment part 20 and the power cable 2.

The relationship between the reaction force T and the shear force P is expressed by the following formula (1).
L>T/(d×π×P)...(1)

In formula (1), L is the length (mm) of the cable conductor 3. In formula (1), d is the diameter (mm) of the cable conductor 3.

Examples of adhesive G include cyanoacrylate adhesives, reactive resin adhesives (reactive acrylics), alkyl cyanoacrylate adhesives, one-part thermosetting epoxy adhesives, methacrylate anaerobic adhesives, α-cyanoacrylate jelly-like instant adhesives, etc. The adhesive G may be any type, such as a jelly or liquid adhesive, as long as it can accumulate in the recess 21B and can bond the mounting portion 20 and the cable conductor 3.

The mounting section 20 is also provided with through holes 21C that penetrate from the outer surface around the inner surface of the mounting section 20 toward the insertion hole 21. In other words, the through holes 21C are disposed at positions in the mounting section 20 that face the side of the cable conductor 3 when the cable conductor 3 is inserted into the insertion hole 21. Four through holes 21C are provided on the upper side of the mounting section 20 in Figs. 1 and 2.

By providing the through hole 21C in this way, after the cable conductor 3 is mounted in the insertion hole 21, it is possible to inject adhesive G between the mounting portion 20 and the cable conductor 3 via the through hole 21C.

In addition, by providing the through hole 21C, when the space between the mounting part 20 and the cable conductor 3 is filled with adhesive G, the adhesive G overflows from the through hole 21C, making it possible to confirm that the space between the mounting part 20 and the cable conductor 3 has been filled with adhesive G.

In addition, by providing the through hole 21C, it is possible to mechanically fix the mounting part 20 and the cable conductor 3 by providing a fixing member 30 such as a set screw through the through hole 21C. The fixing member 30 has, for example, a tip portion that can bite into the cable conductor 3. Note that a hole may be made in the cable conductor 3 so that the tip portion of the fixing member 30 can fit into it.

In this way, by providing the fixing member 30, the mechanical gripping force t2 of the fixing member 30 is added to the total tension (T and t1) described above, and the total tension can be further increased. As a result, the adhesive strength between the mounting portion 20 and the cable conductor 3 can be further increased.

The size of the through hole 21C through which the fixing member 30 is inserted may be different from the size of the other through holes 21C depending on the size of the fixing member 30.

More than one fixing member 30 may be provided. By providing more than one fixing member 30, the mechanical gripping force of the fixing member 30 can be increased, and the adhesive strength between the mounting portion 20 and the cable conductor 3 can be further increased.

Next, we will explain an example of a series of work steps from attaching the pulling eye 1 to the power cable 2 to moving it.

First, the worker applies adhesive G to both the cable conductor 3 of the power cable 2 and the insertion hole 21 of the mounting part 20. Note that the worker may apply adhesive G to either the cable conductor 3 of the power cable 2 or the insertion hole 21 of the mounting part 20.

Next, the worker inserts the cable conductor 3 into the insertion hole 21 of the mounting part 20. After inserting the cable conductor 3 into the insertion hole 21 of the mounting part 20, the worker may also inject adhesive G between the mounting part 20 and the cable conductor 3 through the through hole 21C.

This makes it easier to fill the gap between the cable conductor 3 and the mounting portion 20 with adhesive G. It also enables the worker to check that adhesive G is overflowing from the through hole 21C, which in turn makes it easier to check that adhesive G has filled the gap between the cable conductor 3 and the mounting portion 20.

In addition, after inserting the cable conductor 3 into the insertion hole 21 of the mounting part 20, the worker may mechanically fix the mounting part 20 and the cable conductor 3 using the fixing member 30.

This further increases the adhesive strength between the mounting portion 20 and the power cable 2.

Then, after inserting the cable conductor 3 into the insertion hole 21, the worker leaves the pulling eye 1 and the power cable 2 to allow the adhesive G to harden and bond the mounting part 20 and the power cable 2 together, and then pulls the connecting part 10 of the pulling eye 1 with a traction device or the like to pull the power cable 2 via the mounting part 20. In this way, the power cable 2 is moved to lay or remove the power cable 2.

When using a pulling eye for compression connection to a power cable, it is first necessary to transport a press device for compression connection to the work site, but the weight of the press device increases depending on the size of the power cable 2.

As a result, it is necessary to secure multiple workers to perform the compression connections and to coordinate the work dates and times of these workers, which makes the work more time-consuming and labor-intensive than necessary.

In contrast, in this embodiment, the pulling eye 1 and the power cable 2 are connected with adhesive G, so that the pulling eye 1 and the power cable 2 can be bonded together by a simple process. In other words, in this embodiment, the process of attaching the pulling eye 1 to the power cable 2 is simplified, and the pulling operation of the power cable 2 can be made more efficient.

In addition, a recess 21B is provided on the inner surface of the insertion hole 21 of the mounting part 20, so that the adhesive G can be stored in the recess 21B and hardened. This allows the anchor effect of the adhesive G to increase the adhesive strength between the mounting part 20 and the power cable 2 while stabilizing the tensile force of the power cable 2.

In addition, when the cable conductor 3 is composed of a stranded wire made up of multiple strands twisted together, recesses are also formed between the strands, and adhesive G also accumulates in the recesses on the cable conductor 3 side. This further enhances the anchor effect of the adhesive G that accumulates in the recess 21B and the recess on the cable conductor 3 side, and further stabilizes the tensile force of the power cable 2.

In addition, by allowing the adhesive G to penetrate into the through hole 21C, the anchoring effect of the adhesive G can be further enhanced, and the tensile force of the power cable 2 can be further stabilized.

Also, as shown in FIG. 3, an operator may process and form recesses 3A on the surface of the cable conductor 3 to form an uneven shape, and then accumulate adhesive G in the recesses 3A to enhance the anchoring effect of the adhesive G. Furthermore, the anchoring effect can be enhanced by providing the recesses 3A at a position corresponding to the recesses 21B. This process of processing and forming an uneven shape on the surface of the cable conductor 3 is performed before the process of adhering the cable conductor 3 to the mounting portion, such as before inserting the cable conductor 3 into the insertion hole 21. Furthermore, the uneven shape may be formed by roughening the surface of the cable conductor 3 with a file or the like.

In addition, in the above embodiment, the gap between the inner surface 21A and the cable conductor 3 is extremely small, but if the gap between the mounting portion 20 and the cable conductor 3 becomes somewhat large, for example, as shown in FIG. 4, a spacer 40 may be provided, or a receiving portion 21D may be provided to receive the end face portion of the cable conductor 3 in the insertion hole 21.

The spacer 40 is an elastic member such as rubber or packing, and has, for example, a first part 41 and a second part 42. The first part 41 and the second part 42 are configured in a cylindrical shape so that they can be arranged around the cable conductor 3.

More specifically, the first part 41 is a part that is disposed in the gap between the mounting part 20 and the cable conductor 3, and is configured to extend in a direction along the side surface of the cable conductor 3 (the extension direction of the mounting part 20). The second part 42 is a part that is connected to an end of the first part 41 that corresponds to the edge portion of the insertion hole 21 of the mounting part 20, and is configured to be disposed in close contact with the edge portion, and is configured to protrude further in the radial direction of the cable conductor 3 than the first part 41.

In other words, the spacer 40 has an L-shaped cross section composed of a first portion 41 and a second portion 42. By disposing the first portion 41 of the spacer 40 in the gap between the mounting portion 20 and the cable conductor 3, it becomes easier to maintain the gap at a constant width.

The receiving portion 21D is located at a position corresponding to the end face of the cable conductor 3 in the insertion hole 21, and has a shape that allows the end face to fit. By providing this receiving portion 21D, the end face of the cable conductor 3 is positioned within the insertion hole 21, making it easier to maintain a constant gap between the mounting portion 20 and the cable conductor 3.

The spacer 40 and the receiving portion 21D also keep the gap between the mounting portion 20 and the cable conductor 3 constant, allowing the adhesive to be filled sufficiently and uniformly. As a result, the above-mentioned anchor effect is exerted while the pulling eye 1 is not eccentric in the pulling direction, so no bending moment is applied, the pulling force of the power cable 2 can be further stabilized, and repeated use can be improved.

Also, as shown in Fig. 5, a configuration in which a wedge member 50 is provided may be used. In this embodiment, the mounting part 20 of the pulling eye 1 has a through hole 21E that penetrates from the outer surface of the mounting part 20 to the bottom surface of the insertion hole 21 in the extension direction of the mounting part 20 (left-right direction in Fig. 5) at the bottom surface of the insertion hole 21 (the end surface of the mounting part 20 at one end side in the above-mentioned extension direction). In other words, the through hole 21E is located at a position in the mounting part 20 that faces the end surface of the cable conductor 3 when the cable conductor 3 is inserted into the insertion hole 21.

The wedge member 50 is provided by being driven into the end face of the cable conductor 3 through the through hole 21E. In this way, the end face side portion of the cable conductor 3 is pushed outward (for example, radially) by the wedge member 50 and pressed against the adhesive G that spreads in a planar manner in the gap between the outer periphery of the end face portion of the cable conductor 3 and the inner surface 21A, so that the adhesive force between the end face portion of the cable conductor 3 and the mounting portion 20 can be supplemented. In addition, the end face of the cable conductor 3 can be fixed to the bottom surface portion of the insertion hole 21 by the wedge member 50, so that the adhesive force between the cable conductor 3 and the mounting portion 20 can be enhanced. The traction device may be connected to the connecting portion 10 with the wedge member 50 driven in, or the driven wedge member 50 may be removed after the cable conductor 3 is bonded and then connected to the connecting portion 10. In the former case, the adhesive force between the end face portion of the cable conductor 3 and the mounting portion 20 can be further supplemented by pressing the wedge member 50 in the driving direction with the connecting traction device.

In addition, in the above embodiment, the recess 21B has a threaded shape, but the present invention is not limited to this, and any shape, such as a groove shape or a plurality of recesses, may be used as long as it is possible to store adhesive. In addition, from the viewpoint of improving the anchor effect, the recess may be provided at a position corresponding to the pitch of the stranded wires of the cable conductor 3.

In addition, in the above embodiment, the mounting portion 20 is configured in a cylindrical shape, but the present invention is not limited to this, and any configuration is acceptable as long as adhesive can be filled between the mounting portion 20 and the cable conductor inside the insertion hole.

In addition, in the above embodiment, the connecting part 10 and the mounting part 20 are separate, but the present invention is not limited to this, and the connecting part and the mounting part may be configured as one unit.

In addition, in the above embodiment, the pulling eye 1 is the attachment member, but the attachment part may also be the attachment member.

In addition, in the above embodiment, a through hole 21C is provided, but the present invention is not limited to this, and a through hole does not have to be provided.

In addition, the above embodiments are merely examples of how the present invention can be implemented, and the technical scope of the present invention should not be interpreted in a limiting manner based on these. In other words, the present invention can be implemented in various forms without departing from its gist or main features.

REFERENCE SIGNS LIST 1 Pulling eye 2 Power cable 3 Cable conductor 10 Connection portion 20 Mounting portion 21 Insertion hole 21A Inner surface 21B Recess 21C Through hole 21D Receiving portion 30 Fixing member 40 Spacer 41 First portion 42 Second portion 50 Wedge member

Claims (13)

An attachment member that is attached to a tip portion of a power cable when the power cable is towed,
an attachment portion having an insertion hole into which the tip portion is inserted, a traction portion being provided at one end side of the insertion hole in the extending direction, and an opening at the other end side of the insertion hole in the extending direction to allow the tip portion to be inserted into the insertion hole;
The inner surface of the mounting portion surrounding the internal space of the insertion hole is
An adhesive applying section is provided to apply an adhesive for adhering the tip section,
The adhesive applying portion has a recessed portion recessed outward so that the adhesive applied to the adhesive applying portion can accumulate,
The mounting portion has a through hole penetrating from an outer surface of the mounting portion toward the insertion hole.
An attachment part that is attached to the tip of a power cable. The through hole is provided so that a fixing member for fixing the tip portion inserted into the insertion hole can be inserted therethrough.
A mounting member that is mounted to a tip end of the power cable according to claim 1 . The outer surface includes an outer surface located around the inner surface in the mounting portion,
The through hole is provided penetrating the mounting portion from the outer surface to the insertion hole.
A mounting member that is mounted to a tip end of the power cable according to claim 2 . The through hole is provided so that a wedge member can be inserted into the end surface of the tip portion inserted into the insertion hole.
A mounting member that is mounted to a tip end of the power cable according to claim 1 . When the wedge member is driven into the end surface of the tip portion, the wedge member pushes the end surface of the tip portion outward and presses the end surface against the adhesive between the end surface and the inner surface.
A mounting member to be mounted on the tip end of the power cable according to claim 4 . The outer surface includes an end surface of the mounting portion on one end side in the extending direction,
The through hole is provided penetrating the mounting portion from the end surface to the insertion hole.
A mounting member to be mounted on a tip end of the power cable according to claim 4 or 5 . The mounting portion has a receiving portion on the inner surface that receives an end face portion of the tip portion.
An attachment member to be attached to a tip end of the power cable according to any one of claims 1 to 6 . A spacer is provided between the insertion hole and the tip portion.
An attachment member to be attached to a tip end of the power cable according to any one of claims 1 to 7 . a mounting part having an insertion hole into which a tip end of a power cable is inserted, a pulling part being provided at one end side in an extension direction of the insertion hole, and an opening at the other end side in the extension direction of the insertion hole so that the tip end can be inserted into the insertion hole, the mounting part having a through hole penetrating from an outer surface of the mounting part toward the insertion hole, an inner surface of the mounting part surrounding an internal space of the insertion hole constitutes an adhesive application part where an adhesive for adhering the tip end is applied, and a mounting member having a recessed portion recessed outward so that the adhesive applied to the adhesive application part can accumulate,
an insertion step of inserting the tip portion into the insertion hole; and an application step of applying the adhesive between the tip portion and the inner surface through the through hole after the insertion step, and an adhesion step of adhering the tip portion to the mounting portion;
a pulling step of pulling the power cable by the pulling part via the mounting part after the bonding step;
having
A method of operation for towing the power cable using an attachment member. A processing step of processing and forming an uneven shape on the tip portion before the bonding step is included.
A method for pulling the power cable using the attachment member according to claim 9 . An attachment member that is attached to a tip portion of a power cable when the power cable is towed,
an attachment portion having an insertion hole into which the tip portion is inserted, a traction portion being provided at one end side of the insertion hole in the extending direction, and an opening at the other end side of the insertion hole in the extending direction to allow the tip portion to be inserted into the insertion hole;
The inner surface of the mounting portion surrounding the internal space of the insertion hole is
An adhesive applying section is provided to apply an adhesive for adhering the tip section,
The adhesive applying portion has a recessed portion recessed outward so that the adhesive applied to the adhesive applying portion can accumulate,
The mounting portion has a receiving portion on the inner surface that receives an end face portion of the tip portion.
An attachment part that is attached to the tip of a power cable. An attachment member that is attached to a tip portion of a power cable when the power cable is towed,
a mounting portion having an insertion hole into which the tip portion is inserted, a traction portion being provided at one end side of the insertion hole in the extending direction, and an opening at the other end side of the insertion hole in the extending direction so that the tip portion can be inserted into the insertion hole;
A spacer provided between the insertion hole and the tip portion;
Equipped with
The inner surface of the mounting portion surrounding the internal space of the insertion hole is
An adhesive applying section is provided to apply an adhesive for adhering the tip section,
The adhesive application portion has a recessed portion recessed outward so that the adhesive applied to the adhesive application portion can accumulate.
An attachment part that is attached to the tip of a power cable. a mounting part having an insertion hole into which a tip end of a power cable is inserted, a pulling part being provided at one end side in an extension direction of the insertion hole, and an opening at the other end side in the extension direction of the insertion hole so that the tip end can be inserted into the insertion hole, the mounting part having a through hole penetrating from an outer surface of the mounting part toward the insertion hole, an inner surface of the mounting part surrounding an internal space of the insertion hole constitutes an adhesive application part where an adhesive for adhering the tip end is applied, and a mounting member having a recessed portion recessed outward so that the adhesive applied to the adhesive application part can accumulate,
The method includes an insertion step of inserting the tip portion into the insertion hole, and an application step of applying the adhesive to the tip portion before the insertion step, and an adhesion step of adhering the tip portion to the attachment portion;
a pulling step of pulling the power cable by the pulling part via the mounting part after the bonding step;
having
In the inserting step, the adhesive is applied to an inner surface of the mounting portion by inserting the tip portion into the insertion hole,
In the bonding step, when the adhesive is filled between the tip portion and the inner surface after the insertion step, the adhesive overflows from the through hole.
A method of operation for towing the power cable using an attachment member.

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