A cable-drawn head and method of using the same

Abstract

This invention discloses a cable traction head and its usage method, comprising a main body rod; one end of the main body rod is integrally formed with a pull ring, and the other end of the main body rod has an insertion cavity for inserting the cable core; it also includes a guide kit, which comprises two integrally formed parts, a tapered sleeve and an installation tube, the end of the inner cavity of the installation tube having an internal thread, and the surface of the main body rod away from the insertion cavity having an external thread; after welding, the installation tube is fixedly installed on the main body rod by the engagement of the internal and external threads; this invention achieves a high-strength metallurgical bond, forming a wave-shaped metallurgical bond between the steel traction head and the aluminum core at the interface through explosive welding; it has extremely fast construction speed, greatly improving laying efficiency; it has high energy utilization and low explosive dosage: through the design of the external constraint sleeve, the explosive dosage can be reduced by about 20%-35%, resulting in lower cost, smaller explosive yield, and greater safety.

Description

Technical Field

[0001] This invention relates to the field of cable construction, specifically to a cable traction head and its usage method. Background Technology

[0002] A cable puller is a mechanical connector installed at the end of a cable. Its core structure typically includes a puller body and a crimping or fastening device for securing the cable conductor. Its main function is to concentrate and effectively transfer the pulling force from a pulling machine or manual dragging to the cable conductor during cable laying (such as pulling into ducts, tunnels, or laying along cable trays). This avoids the pulling force directly acting on the cable's insulation, sheath, or other vulnerable parts, preventing the cable from being pulled, deformed, or damaged during construction. In existing technologies, cable pullers are usually directly crimped or fixed to the cable conductor.

[0003] For example, our company's earlier patent application, publication number CN121282773A, discloses a cable laying traction structure and installation method. The structure includes an inner traction kit, an outer traction kit, and a clamping nut. The outer traction kit includes an outer sleeve with a mounting hole at one end. The inner traction kit includes an inner sleeve coaxially arranged with the outer sleeve. One end of the inner sleeve is detachably fixed in the mounting hole, and the other end has a blind hole. A frustum-shaped clamping part is provided on the outside of the opening end of the blind hole. The clamping nut includes a coaxial hexagonal section and a sealing section that mates with the mounting hole. The sealing section is threaded into the mounting hole. The sealing section has a pressure hole that mates with the clamping part. The hexagonal section has a cable through hole that communicates with the pressure hole. The cable core passes through the cable through hole and is inserted into the blind hole. A sheath is sleeved on the outside of the cable core. The sheath is sealed and clamped between the pressure hole and the clamping part.

[0004] The aforementioned patent has advantages such as good sealing effect and high reliability; however, the disadvantage of the aforementioned patent is that: in this patent, the main force of the cable during traction is borne by the joint between the inner sleeve and the cable core. In this patent, hydraulic clamps are used to press two to three times in the middle section of the inner sleeve to fix the inner sleeve and the cable core. The structural strength of this fixing method is generally weak and it is only suitable for light cables. The joint is prone to separation during traction.

[0005] Therefore, it is necessary to improve such a structure to overcome the above-mentioned defects. Summary of the Invention

[0006] The purpose of this invention is to provide a cable traction head and its usage method to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A cable traction head includes a main body rod; one end of the main body rod is integrally formed with a pull ring, and the other end of the main body rod has an insertion cavity for inserting the core of a cable; it also includes a guide kit, which comprises two integrally formed parts, a tapered sleeve and an installation tube, the end of the inner cavity of the installation tube having an internal thread, and the surface of the main body rod away from the insertion cavity having an external thread; after welding, the installation tube is fixedly installed on the main body rod by the engagement of the internal and external threads, and at the same time, the inner cavity of the tapered sleeve is bonded to the sheath and insulation layer with adhesive.

[0009] Furthermore, the core material is aluminum, and the main body is made of No. 45 steel.

[0010] Furthermore, it also includes an explosive mounting ring; the explosive mounting ring is sleeved on the outside of the insertion cavity when welding the main body rod and the wire core 9; the inner wall of the explosive mounting ring has an explosive mounting cavity for mounting explosives, and one end of the mounting cavity also has a detonator mounting cavity for mounting detonators; the inner and outer walls of the insertion cavity are inclined, that is, the cross-section of the insertion cavity is an isosceles trapezoid, and the angle between the inner wall of the insertion cavity and the horizontal direction is 5°-15°.

[0011] Furthermore, the outer wall of the insertion cavity is provided with several grooves with an arc-shaped cross section. When the insertion cavity deforms, the insertion cavity mainly undergoes tilting deformation at the grooves, so that the inner wall of the insertion cavity merges with the wire core.

[0012] A method for using a cable traction head includes the following steps:

[0013] S1. Welding Surface Treatment: Before welding, a certain length of aluminum wire core is stripped from the cable end, while ensuring that the stripped sheath and insulation layer are conical in shape. Before welding, the surface of the aluminum wire core and the inner wall of the steel insertion cavity must be polished and cleaned to completely remove the oxide layer.

[0014] S1. Installation and sealing: Insert the aluminum wire core into the insertion cavity and install a temporary sealing cap at the open end (in this solution, solid glue is used to fill the open end) to prevent the intrusion of explosion products.

[0015] S2. Detonation and initiation: Approximately 307 grams of explosives are evenly applied to the corresponding area on the outer wall of the towing head, an electronic detonator is installed, and the explosives are remotely initiated after personnel have evacuated.

[0016] S3. Quality Inspection: After welding, the joint should be subjected to tensile testing (fracture should occur in the aluminum conductor itself) and ultrasonic testing; after the sample is cut open, the metal should show the corresponding wavy metallurgical interface; after determining the fixing effect of a batch of cables, the appropriate specifications of the explosive installation cavity and the amount of explosive can be selected according to the actual situation. If it is put into actual use later, no testing is required.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] Achieving high-strength metallurgical bonding involves explosive welding to create a wave-shaped metallurgical bond between the steel traction head and the aluminum wire core at the interface. This bond has a higher strength than the conductor itself and avoids electrochemical corrosion.

[0019] Completely free from reliance on large equipment, the entire connection process only requires laying explosives and detonation, eliminating the need for heavy equipment such as hydraulic presses and smelting furnaces, making it particularly suitable for field, tunnel, and emergency repair situations.

[0020] The construction speed is extremely fast: from preparation to completion of welding, it only takes a few minutes, which greatly improves the laying efficiency.

[0021] High energy efficiency and low explosive dosage: The design of the external restraint sleeve can reduce the explosive dosage by about 20%-35%, resulting in lower cost, smaller explosive yield, and greater safety. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a cable traction head.

[0023] Figure 2 This is a schematic diagram of the internal structure of a cable traction head.

[0024] Figure 3 This is a structural schematic diagram of a cable traction head and its central main rod.

[0025] Figure 4 This is a schematic diagram of a cable traction head and guide kit.

[0026] Figure 5 This is an internal schematic diagram of a cable traction head and guide kit.

[0027] Figure 6 This is a schematic diagram of a metallurgical bonding interface. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-4 A cable traction head, comprising a main body rod 100;

[0030] One end of the main body rod 100 is integrally formed with a pull ring 101, and the other end of the main body rod 100 is provided with an insertion cavity 102, which is used to insert the wire core 901 of the cable 900.

[0031] It also includes an explosive mounting ring 200. The explosive mounting ring 200 is sleeved on the outside of the insertion cavity 102 when welding the main body rod 100 and the wire core 901; the inner wall of the explosive mounting ring 200 is provided with an explosive mounting cavity 201 for mounting explosives, and at the same time, one end of the mounting cavity 201 is also provided with a detonator mounting cavity 202 for mounting detonators;

[0032] The inner and outer walls of the insertion cavity 102 are inclined, meaning the cross-section of the insertion cavity 102 is an isosceles trapezoid, and the angle between the inner wall of the insertion cavity 102 and the horizontal direction is 5°-15°.

[0033] In this design, the core 901 is made of aluminum, and the main body rod 100 is made of No. 45 steel.

[0034] It also includes a guide kit 300, which comprises two integrally formed parts: a tapered sleeve 301 and a mounting tube 302. The end of the inner cavity of the mounting tube 302 is provided with an internal thread.

[0035] In this design, the surface of the main body rod 100 away from the insertion cavity 102 is provided with external threads; after welding, the mounting tube 302 is fixedly installed on the main body rod 100 by the engagement of internal and external threads, and at the same time, the inner cavity of the tapered sleeve 301 is bonded to the sheath and the insulating layer with glue.

[0036] In this embodiment, a 110kV aluminum conductor high-voltage cable with a cross-section of 2500mm² is taken as an example.

[0037] Aluminum wire core (substrate): Diameter Dc = 56.4 mm, density ρAl = 2.70 g / cm³ 3

[0038] Cable traction head, specifically referring to the side wall (cladding) of insertion cavity 102: the diameter D of the insertion cavity. h =56.8mm (0.2mm gap on one side), weld zone length L=100mm, material: 45 steel, density ρSt=7.85g / cm³ 3

[0039] Effective deformation wall thickness t f =5mm

[0040] Explosive: Expanded ammonium nitrate oil explosive is selected, with a density ρe =0.75g / cm3, target burst speed v d =2100m / s.

[0041] 1. Calculate the effective mass mf of the steel cladding plate.

[0042] The cladding plate is the sidewall of the insertion cavity 102, and its effective volume V f For: Vf=π*[(2D h +t f )2−(2Dh)2]*L=π*[(28.4+5)2−(28.4)2]*100≈97.8cm 3

[0043] Composite board quality: m f =ρSteel*Vf=7.85*97.8≈767.7g

[0044] 2. Determine the mass ratio R of explosives to composite plates.

[0045] For steel-aluminum explosive welding, in order to achieve good waveform bonding, the collision velocity v p Typically, a speed of 300-500 m / s is required; the target value v is taken. p =400m / s, explosion velocity v d =2100m / s.

[0046] When joining high-density metals such as steel, the typical R value range is 0.3-0.6, and we have selected 0.4.

[0047] 3. Calculate the total charge W total

[0048] W total =R*m f =0.4 * 767.7 ≈ 307.1g

[0049] 4. Calculate the thickness δ0 of the medication application.

[0050] The area for drug delivery is the outer surface area S of the welded section of the steel traction head.

[0051] S=π*(D h +2t f )*L=π*(56.8+10)*100≈209.8cm2

[0052] Drug application thickness: δ0=W total / ρ e *S=307.1 / 0.75*209.8≈1.95cm=19.5mm.

[0053] A method for using a cable traction head includes the following steps:

[0054] Welding surface treatment: Before welding, a certain length of aluminum wire core is stripped from the cable end, while ensuring that the stripped sheath and insulation layer are conical in shape.

[0055] Before welding, the surface of the aluminum wire core and the inner wall of the steel insertion cavity must be polished and cleaned to completely remove the oxide layer.

[0056] Installation and sealing: Insert the aluminum wire core into the insertion cavity and install a temporary sealing cap at the open end (in this solution, solid glue is used to fill the open end) to prevent the intrusion of explosion products.

[0057] Placement and detonation: Approximately 307 grams of explosives are evenly placed on the corresponding area of ​​the outer wall of the towing head, an electronic detonator is installed, and the explosive is detonated remotely after personnel have evacuated.

[0058] Quality inspection: Post-weld joints should undergo tensile testing (fracture should occur within the aluminum conductor itself) and ultrasonic testing. After dissecting the sample, its metallographic structure is as follows: Figure 6 The wave-shaped metallurgical bonding interface is shown.

[0059] After determining the fixing effect of a batch of cables, the appropriate specifications and amount of explosives for the explosive installation cavity can be selected according to the actual situation. After that, no testing is required before putting it into actual use.

[0060] This scheme, by setting a reasonable effective deformable wall thickness (5mm) and mass ratio (0.4), yields a feasible total drug weight of approximately 307 grams. Furthermore, adjustments (±15%) can be made based on actual conditions during practical use.

[0061] In a further embodiment of this solution, the explosive is installed in the explosive mounting cavity 201 within the explosive mounting ring 200;

[0062] Due to the constraint effect, the same collision velocity v is achieved. p The required mass ratio can be reduced. Based on engineering experience, the R value can be taken as 65%-80% of the original value; that is, the subsequent total charge W. total Both the thickness of the dressing and the medicated patch δ can be 65%-80% of the original value;

[0063] In this embodiment, during the explosive placement and detonation steps: approximately 100% explosive is evenly placed in the corresponding area within the explosive installation ring 200, an electronic detonator is installed, and the explosive is detonated remotely after personnel have evacuated.

[0064] In some embodiments of this solution, the outer wall of the insertion cavity 102 is provided with several grooves 103 with an arc-shaped cross section. When the insertion cavity 102 deforms, the insertion cavity 102 mainly undergoes tilting deformation at the grooves 103, so that the inner wall of the insertion cavity 102 is fused with the wire core 901. In this embodiment, the explosive can be further reduced according to the actual situation.

[0065] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connect" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

Claims

1. A cable traction head, comprising a main body rod; characterized in that, One end of the main rod is integrally formed with a pull ring, and the other end of the main rod has an insertion cavity for inserting the cable core. It also includes a guide kit, which consists of two integrally formed parts: a tapered sleeve and an installation tube. The end of the inner cavity of the installation tube has an internal thread, and the surface of the main rod away from the insertion cavity has an external thread. After welding, the installation tube is fixedly installed on the main rod by the engagement of the internal and external threads. At the same time, the inner cavity of the tapered sleeve is bonded to the sheath and insulation layer with glue.

2. The cable traction head according to claim 1, characterized in that, The core material is aluminum, and the main body is made of No. 45 steel.

3. A cable traction head according to claim 1, characterized in that, It also includes an explosive mounting ring; the explosive mounting ring is sleeved on the outside of the insertion cavity when welding the main body rod and the wire core 9; the inner wall of the explosive mounting ring has an explosive mounting cavity for mounting explosives, and one end of the mounting cavity also has a detonator mounting cavity for mounting detonators; the inner and outer walls of the insertion cavity are inclined, that is, the cross-section of the insertion cavity is an isosceles trapezoid, and the angle between the inner wall of the insertion cavity and the horizontal direction is 5°-15°.

4. A cable traction head according to claim 1, characterized in that, The outer wall of the insertion cavity is also provided with several grooves with an arc-shaped cross section. When the insertion cavity deforms, the insertion cavity mainly undergoes tilting deformation at the grooves, so that the inner wall of the insertion cavity merges with the wire core.

5. A method of using a cable traction head, characterized in that, Specifically, the following steps are included: S1. Welding Surface Treatment: Before welding, a certain length of aluminum wire core is stripped from the cable end, while ensuring that the stripped sheath and insulation layer are conical in shape. Before welding, the surface of the aluminum wire core and the inner wall of the steel insertion cavity must be polished and cleaned to completely remove the oxide layer. S1. Installation and sealing: Insert the aluminum wire core into the insertion cavity and install a temporary sealing cap at the open end (in this solution, solid glue is used to fill the open end) to prevent the intrusion of explosion products. S2. Detonation and initiation: Approximately 307 grams of explosives are evenly applied to the corresponding area on the outer wall of the towing head, an electronic detonator is installed, and the explosives are remotely initiated after personnel have evacuated. S3. Quality Inspection: After welding, the joint should be subjected to tensile testing (fracture should occur in the aluminum conductor itself) and ultrasonic testing; after the sample is cut open, the metal should show the corresponding wavy metallurgical interface; after determining the fixing effect of a batch of cables, the appropriate specifications of the explosive installation cavity and the amount of explosive can be selected according to the actual situation. If it is put into actual use later, no testing is required.

6. The method of using the cable traction head according to claim 5, characterized in that: The method for calculating the amount of medicine applied. The cable is a 110kV, 2500mm² aluminum conductor high-voltage cable. Aluminum wire core (substrate): diameter Dc = 56.4 mm, density pAl = 2.70 g / cm 3 Cable traction head, specifically referring to the side wall (cladding) of insertion cavity 102: the diameter D of the insertion cavity. h =56.8mm (0.2mm gap on one side), weld zone length L=100mm, material: 45 steel, density ρSt=7.85g / cm³ 3 Effective deformation wall thickness t f = 5 mm; Explosive: Choose the ammonium oil explosive, density p e = 0.75 g / cm3, target explosion speed v d = 2100 m / s; S1. Calculate the effective mass mf of the steel cladding plate. The complex plate is inserted into the side wall of the cavity 102, and its effective volume V f is: Vf=π*[(2D h +t f )2−(2Dh)2]*L=π*[(28.4+5)2−(28.4)2]*100≈97.8cm 3 Plating mass: m f = pSteel * Vf = 7.85 * 97.8 ≈ 767.7 g S2. Determine the mass ratio R of explosive to composite plate. For steel-aluminum explosive welding, to achieve good wave-shaped bonding, the collision speed v p Usually needs to reach 300-500 m / s, taking the target value v p = 400 m / s, the detonation velocity v d = 2100 m / s; When joining high-density metals such as steel, the typical R value range is 0.3-0.6, and we have selected 0.

4. S3, calculate total charge amount W total W total =R*m f =0.4*767.7≈307.1g S4. Calculate the drug application thickness δ0 The area for drug delivery is the outer surface area S of the welded section of the steel traction head. S = π * (D h + 2t f )*L = π * (56.8 + 10) * 100 ≈ 209.8 cm2 Drug application thickness: δ0=W total / ρ e *S=307.1 / 0.75*209.8≈1.95cm=19.5mm.

7. The method for calculating the amount of medicine applied according to claim 6, characterized in that: The explosive is installed in the explosive mounting cavity 201 within the explosive mounting ring 200; due to the constraint effect, the mass ratio required to achieve the same collision velocity vp can be reduced; based on engineering experience, the R value can be taken as 65%-80% of the original value; that is, the subsequent total charge W total The thickness δ of both the medicine and the dressing can be 65%-80% of the original value.

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