Double-bolt pressure self-balancing parallel groove clamp

Abstract

The invention belongs to the technical field of electric power fittings, and provides a double-bolt pressure self-balancing type parallel groove clamp which comprises a U-shaped clamping block, two sets of bolt fastening assemblies, four movable clamping blocks and two limiting blocks. The movable clamping blocks are arranged in an inner cavity of the U-shaped clamping block in an axial symmetry sliding manner; a first groove is formed in the inner side wall of the U-shaped clamping block, and a second groove opposite to the first groove is formed in the outer side wall of each movable clamping block. Stepless position adjustment of the movable clamping block can be achieved in the extending direction of the sliding groove, and different-diameter oval wire containing grooves with different radial size proportions can be flexibly formed by adjusting the relative distance between the movable clamping block and the clamping part of the U-shaped clamping block, so that the connection requirements of cables with different nominal cross sections and different wire diameter specifications are met, and the connection efficiency is improved. The scene adaptability and the site construction convenience of the wire clamp are greatly improved, and the diversified operation requirements of the distribution network project are met.

Description

Technical Field

[0001] This invention relates to the field of power fittings technology, and specifically to a parallel groove clamp, which is a double-bolt pressure self-balancing type parallel groove clamp. Background Technology

[0002] With the continuous advancement of my country's power distribution network construction and the deepening of urban and rural power grid upgrading and transformation, the coverage of overhead distribution lines and low-voltage cable lines continues to expand. The safety, reliability, and ease of operation and maintenance of these lines have become core performance indicators for power grid construction. Parallel cable clamps, as the most widely used and numerous connecting hardware in distribution network systems, have the core function of enabling uninterrupted connection, current splitting, and branch T-connection of two parallel conductors without cutting off the main conductor. Their structural performance, clamping reliability, and environmental adaptability directly determine the current-carrying stability and operational safety of the line.

[0003] Currently, the most widely used type in the industry is the double-bolt parallel groove clamp. Its core structure typically includes corresponding upper and lower clamps. Semi-circular grooves for accommodating conductors are cut into corresponding positions on the upper and lower clamps. Each end of the upper and lower clamps is rigidly locked by a fastening bolt and a locking nut. The bolt preload forces the upper and lower clamps together, completing the clamping and fixing of the conductor and ensuring electrical continuity. Compared to single-bolt parallel groove clamps, the double-bolt structure offers a longer clamping length, a larger conductor contact area, and a higher rated gripping force. It is the mainstream product for conductor splicing in 10kV and below medium and low voltage distribution lines. Its technical solution has been incorporated into industry and national mandatory standards such as DL / T765.1-2018 "Technical Conditions for Overhead Distribution Line Fittings" and GB2314-2008 "General Technical Conditions for Power Fittings".

[0004] However, in long-term engineering applications and line operation and maintenance practices, the existing double-bolt parallel groove clamps have extremely poor compatibility for different diameter splicing, and cannot reliably realize cross-specification splicing operations between thin and thick cables, thus failing to meet the core engineering requirements of T-connection of distribution network line branches.

[0005] Existing conventional double-bolt parallel groove clamps use symmetrical, equal-diameter semi-circular grooves on the upper and lower clamps to accommodate conductors (as in patent document CN121011862A). This means the groove radii on the upper and lower clamps are completely identical, and the two sets of clamping grooves corresponding to the double bolts are of uniform specifications. This design only allows for the splicing of two conductors with the same nominal cross-section or a diameter difference of no more than one specification grade, of equal or near-equal diameter. However, in 10kV and below medium- and low-voltage distribution network projects, the most critical and common construction scenario is the T-junction of line branches: that is, the main line uses a 120mm... 2 240mm 2 Large cross-section thick cables are used, while 16mm² cables are used for the incoming branch and equipment power supply branch.2 25mm 2 35mm 2 For small-section, thin cables, it is necessary to directly connect the thin cable to a thick cable to achieve uninterrupted current shunting. For this type of connection requirement with significant differences in cable diameter, existing conventional equal-diameter parallel groove clamps are completely incapable of providing reliable clamping: if the groove specification matches the thick cable, there is a large gap between the thin cable and the inner wall of the groove, making effective surface contact and clamping impossible, resulting in almost zero clamping force. This easily leads to wire pull-out, slippage, and disconnection. If the groove specification matches the thin cable, the thick cable cannot be embedded in the groove, only forming partial line contact with the groove edge. Forcibly tightening the bolts can damage the thick cable core, causing strand breakage, and also causes severe misalignment of the clamp, further exacerbating the risk of clamping failure and poor contact.

[0006] While some existing technologies feature fixed-diameter grooved clamps (such as patent document CN105958409A) that adapt to different diameter connections by creating grooves of varying radii on the upper and lower clamps, the groove specifications of these clamps are fixed combinations. A single clamp can only accommodate one fixed combination of thick and thin conductor cross-sections, failing to achieve continuous adaptation for different conductor thicknesses. Furthermore, the diverse conductor thickness combinations in power distribution networks necessitate that construction workers carry dozens of different sizes of clamps for high-altitude operations, resulting in a heavy workload and extremely low construction efficiency. Simultaneously, these fixed-diameter grooved clamps still fail to address the inherent defect of uneven force distribution on the two bolts. The difference in compression between the thick and thin conductors leads to an inherent imbalance in the tightening force of the two bolts, further amplifying the problems of clamp misalignment and poor fit, posing a serious safety hazard for long-term line operation. Summary of the Invention

[0007] The purpose of this invention is to provide a double-bolt pressure self-balancing grooved clamp, which solves the problem that existing double-bolt grooved clamps have extremely poor compatibility with different diameter connections, cannot reliably realize cross-specification connection operations between thin and thick cables, and cannot meet the technical requirements of T-connection of distribution network lines.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A double-bolt pressure self-balancing grooved wire clamp includes a U-shaped clamping block and two sets of bolt fastening components, as well as four movable clamping blocks and two limiting blocks; The movable clamping blocks are slidably arranged in the inner cavity of the U-shaped clamping blocks in an axisymmetric manner; the inner sidewall of the U-shaped clamping blocks is provided with a first groove, and the outer sidewall of each movable clamping block is provided with a second groove arranged opposite to the first groove. The opposing first groove and the second groove together form a wire receiving groove. The two limiting blocks are respectively disposed between the two movable clamping blocks of the two sets of clamping components. The sidewalls of the limiting blocks facing the movable clamping blocks on both sides are provided with a first inclined surface, and the sidewalls of the movable clamping blocks facing the corresponding limiting blocks are provided with a second inclined surface that is adapted and fits against the first inclined surface. Both the inner walls of the first and second grooves are provided with thermal compensation pressure equalization pads, which are made of manganese copper-based anti-invar negative thermal expansion alloy.

[0009] The above technical solution further includes: The U-shaped clamping block has a sliding groove corresponding to the position of the moving clamping block of each clamping component, and the bottom of the moving clamping block has an integrally formed slider that slides in cooperation with the sliding groove.

[0010] Each bolt fastening assembly includes a bolt, a second washer, an elastic washer, and a nut. The limiting block has an axially penetrating bolt mounting hole in the middle. The bolt passes through the second washer, the groove, and the bolt mounting hole from bottom to top, and then the elastic washer is fitted and threadedly connected to the nut.

[0011] The lower surface of the slider protrudes from the lower surface of the U-shaped clamping block, and the lower end face of the slider is fixedly connected to a first pad by a fastening screw. The radial profile dimension of the first pad is greater than the groove width of the slide.

[0012] The first pad has symmetrically arranged positioning blocks integrally formed on the side surface facing the movable clamping block. The lower end face of the movable clamping block has a positioning groove that matches the shape of the positioning block, and the positioning block is embedded in the positioning groove.

[0013] The two first inclined surfaces on both sides of the same limiting block are arranged symmetrically, and the inclined surface mating structure corresponding to the two sets of clamping components is set symmetrically with the longitudinal central axis of the U-shaped clamping block as the axis of symmetry.

[0014] The heat-compensating pressure equalization pad is attached and fixed to the inner wall of the first groove and the second groove, and its working surface is adapted to the outer wall contour of the cable to be clamped.

[0015] The slider can slide steplessly along the extension direction of the groove to adjust the radial dimension of the guide wire receiving groove.

[0016] When the bolt is tightened, the locking force of the nut drives the limiting block to make longitudinal feed motion along the bolt axis. The force is reversed and transmitted through the inclined surface cooperation structure between the limiting block and the moving clamping block, which transforms the longitudinal linear feed motion of the limiting block into the horizontal lateral pushing motion of the moving clamping block along the slide groove. At the same time, the synchronous linkage of the two sets of symmetrically arranged inclined surface cooperation structures makes the clamping force of the moving clamping blocks on both sides automatically and evenly distributed.

[0017] The beneficial effects of this invention are: 1. The movable clamp of the present invention can be infinitely adjusted in position along the extension direction of the slide groove. By adjusting the relative distance between the movable clamp and the U-shaped clamp holding part, different radial dimension ratio elliptical conductor receiving grooves can be flexibly formed, thereby adapting to the splicing requirements of cables with different nominal cross sections and different wire diameters, greatly improving the scene adaptability and on-site construction convenience of the clamp, and meeting the diverse operation requirements of power distribution network projects.

[0018] 2. During the tightening of bolts, the locking force of the nut drives the limiting block to move longitudinally along the bolt's axial direction. The inclined surface cooperation structure between the limiting block and the moving clamping block enables the force to be transferred in a different direction, transforming the longitudinal linear feed motion of the limiting block into the horizontal lateral pushing motion of the moving clamping block along the slide groove. At the same time, the synchronous linkage of two sets of symmetrically arranged inclined surface cooperation structures enables the automatic and balanced distribution of the clamping force of the moving clamping blocks on both sides, ensuring that the clamping pressure in each conductor receiving groove is uniform and consistent, fundamentally eliminating the safety hazards of loose cable clamping and poor contact.

[0019] 3. The present invention uses a thermal compensation pressure equalization gasket made of manganese copper-based anti-invar negative thermal expansion alloy, which can accurately offset the deformation caused by the thermal expansion of the cable or clamping part. When the cable or clamping part undergoes thermal expansion and contraction, the thermal compensation pressure equalization gasket undergoes the opposite thermal contraction and expansion, and the deformation of the two completely cancels each other out, always maintaining the bolt preload, eliminating the gap between the upper and lower clamping plates, and further ensuring that the clamping force on the cable is synchronously balanced throughout the process, realizing self-balancing of clamping pressure under all working conditions and throughout the entire life cycle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 yes Figure 1 Cross-sectional view at point AA; Figure 3 This is a side view of the present invention; Figure 4 This is a schematic diagram of the U-shaped clamping block structure in this invention; Figure 5 This is a schematic diagram of the movable clamping block structure in this invention; Figure 6 This is a schematic diagram of the limiting block structure in this invention.

[0021] In the diagram: 1. U-shaped clamping block; 2. Moving clamping block; 3. Limiting block; 4. First inclined surface; 5. Second inclined surface; 6. First groove; 7. Second groove; 8. Thermal compensation pressure equalization pad; 9. Slide groove; 10. Slider; 11. First pad; 12. Screw; 13. Positioning block; 14. Positioning groove; 15. Second pad; 16. Bolt. Detailed Implementation

[0022] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 , Figure 4 , Figure 5 as well as Figure 6 As shown, a double-bolt pressure self-balancing grooved wire clamp includes a U-shaped clamping block 1, four movable clamping blocks 2, and two limiting blocks 3.

[0024] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, the four movable clamping blocks 2 are divided into two groups of clamping components, with each group consisting of two blocks. The two groups of clamping components are symmetrically arranged in the inner cavity of the U-shaped clamping block 1 with the longitudinal central axis of the U-shaped clamping block 1 as the axis of symmetry. The inner side wall of the U-shaped clamping block 1 is provided with a first groove 6, and the outer side wall of each movable clamping block 2 is provided with a corresponding second groove 7. The first groove 6 and the second groove 7 on the same side are arranged opposite each other. After the first groove 6 and the corresponding second groove 7 are spliced ​​together, they form an elliptical wire receiving groove for clamping the cable to be connected. The elliptical groove structure achieves stable clamping of the cable, improving the cable contact area and clamping reliability.

[0025] Furthermore, the first groove 6 and the second groove 7 are provided with thermal compensation pressure equalization pads 8 having negative thermal expansion properties. The thermal compensation pressure equalization pads 8 are made of Invar alloy, preferably manganese copper-based anti-Invar alloy (manganese copper-based anti-Invar alloy is an alloy with negative thermal expansion properties, capable of thermal contraction and expansion), and its linear thermal expansion coefficient at room temperature is -10×10⁻⁶. -6 K -1 ~-30×10 -6 K -1 It covers the absolute value of the thermal expansion coefficient of copper or aluminum. By adjusting the composition ratio of the manganese copper-based anti-invar negative thermal expansion alloy, its linear thermal expansion coefficient can be precisely controlled so that it tends to be consistent with the absolute value of the linear thermal expansion coefficient of copper or aluminum cables. This achieves a 1:1 precise cancellation of the thermal expansion deformation of the cable or clamping part during temperature changes, maintaining the balance of clamping pressure from the source.

[0026] In this embodiment, the stable operating temperature range of the manganese copper-based anti-Invar negative thermal expansion alloy is -50℃ to 120℃, which completely covers the extreme ambient temperature and line operating temperature rise range of overhead power distribution lines in northern and southern my country. There is no crystal phase transformation within the entire operating temperature range, and the negative thermal expansion performance is stable and does not decay over a long period of time, thus avoiding the fatigue failure problem of traditional disc spring compensation schemes.

[0027] In terms of mechanical properties and service durability, the manganese-copper-based anti-invar negative thermal expansion alloy used in this embodiment has a tensile strength ≥450MPa and an elongation ≥22%, possessing excellent toughness, impact resistance, and fatigue resistance. It can withstand alternating loads caused by long-term wind vibration, icing and de-icing, and short-circuit electrodynamics without plastic deformation or performance degradation. Its atmospheric corrosion resistance is superior to that of ordinary Q235 carbon steel and close to that of H62 brass. It can serve stably for a long time in harsh outdoor environments such as humidity, acid rain, and salt spray. Its service life is completely matched with that of the aluminum alloy parallel groove clamp body, eliminating the need for mid-term replacement and maintenance.

[0028] Regarding environmental protection and safety compliance, the core components of the manganese-copper-based anti-invar negative thermal expansion alloy used in this embodiment are manganese, copper, and nickel, all of which are non-toxic industrial metals, free of heavy metal elements such as lead and cadmium, and non-radioactive. It fully complies with EU RoHS and REACH environmental standards and domestic environmental requirements for power fittings. There are no safety risks for outdoor use or human contact with construction personnel.

[0029] In terms of mass production feasibility and cost control, this alloy uses bulk industrial metal raw materials, and mature vacuum melting, continuous casting and profile processing mass production processes have been achieved in China. The mass production price per ton is close to that of 304 stainless steel, and far lower than that of precious metal invar alloys and synthetic negative thermal expansion ceramics. The cost of large-scale production and application is completely controllable. At the same time, China has a complete processing supply chain, and standard-specification gaskets can be directly machined from bar stock. The processing technology is the same as that of ordinary stainless steel gaskets, without the need for additional special equipment, which is suitable for the large-scale mass production needs of power fittings.

[0030] Please see Figure 3 and Figure 6 As shown, the two limiting blocks 3 are respectively installed between the two movable clamping blocks 2 of the two sets of clamping components; the side of the limiting block 3 facing the movable clamping block 2 is formed with a first inclined surface 4, and the side of the movable clamping block 2 facing the corresponding limiting block 3 is formed with a second inclined surface 5 that matches the first inclined surface 4. The corresponding first inclined surface 4 and second inclined surface 5 fit and abut against each other.

[0031] Please see Figure 4 As shown, the U-shaped clamping block 1 has a sliding groove 9 at the position corresponding to the middle of the movable clamping block 2.

[0032] Please see Figure 3 and Figure 5As shown, the bottom of the movable clamping block 2 is integrally formed with a slider 10. The slider 10 is embedded in the slide groove 9 and forms a sliding fit with it. The lower surface of the slider 10 protrudes from the lower surface of the U-shaped clamping block 1. The lower end face of the slider 10 is fixedly connected to a first pad 11 by a fastening screw 12. The radial profile dimension of the first pad 11 is larger than the groove width of the slide groove 9, which is used to limit the axial displacement of the movable clamping block 2, prevent the slider 10 from coming out of the upper end of the slide groove 9, and ensure the structural stability of the sliding fit.

[0033] Please see Figure 3 and Figure 5 As shown, further, the first pad 11 has symmetrically arranged positioning blocks 13 integrally formed on one side surface facing the movable clamping block 2; the lower end face of the movable clamping block 2 is provided with a positioning groove 14 that is completely adapted to the outer dimensions of the positioning block 13. The positioning block 13 is embedded in the positioning groove 14 to limit the installation position of the first pad 11 in the circumferential and radial directions, eliminate assembly gaps, and ensure connection accuracy and structural reliability.

[0034] Please see Figure 3 and Figure 6 As shown, the center of the limiting block 3 has an axially penetrating bolt 16 mounting hole. The bolt 16 passes through the second pad 15, the slide groove 9, and the bolt 16 mounting hole from bottom to top, and then a flexible washer is fitted and threadedly connected to the nut. The second pad 15 is located below the slide groove 9 and between the bolt head of the bolt 16 and the lower surface of the U-shaped clamping block 1. The flexible washer is located between the nut and the upper end face of the limiting block 3.

[0035] In this embodiment, during the tightening of bolt 16, the locking force of the nut drives the limiting block 3 to move longitudinally along the axial direction of bolt 16. The force is reversed and transmitted through the inclined surface cooperation structure between the limiting block 3 and the moving clamping block 2, transforming the longitudinal linear feed motion of the limiting block 3 into the horizontal lateral pushing motion of the moving clamping block 2 along the slide groove 9. At the same time, through the synchronous linkage of the two sets of symmetrically arranged inclined surface cooperation structures, the clamping force of the moving clamping blocks 2 on both sides is automatically and evenly distributed, ensuring that the clamping pressure in each wire receiving groove is uniform and consistent, fundamentally eliminating the safety hazards of loose cable clamping and poor contact.

[0036] In addition, the movable clamp 2 can be infinitely adjusted in position along the extension direction of the slide groove 9. By adjusting the relative distance between the movable clamp 2 and the clamping part of the U-shaped clamp 1, different radial dimension ratios of elliptical conductor receiving grooves can be flexibly formed, thereby adapting to the splicing requirements of cables with different nominal cross sections and different wire diameters, greatly improving the scene adaptability and on-site construction convenience of the clamp, and meeting the diverse operation requirements of power distribution network projects.

[0037] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A double-bolt pressure self-balancing grooved wire clamp, comprising a U-shaped clamping block (1) and two sets of bolt (16) fastening assemblies, characterized in that, It also includes four movable clamping blocks (2) and two limiting blocks (3); The movable clamping block (2) is axially symmetrically slidably disposed in the inner cavity of the U-shaped clamping block (1); the inner side wall of the U-shaped clamping block (1) is provided with a first groove (6), and the outer side wall of each movable clamping block (2) is provided with a second groove (7) arranged opposite to the first groove (6). The first groove (6) and the second groove (7) arranged opposite to each other form a wire receiving groove. The two limiting blocks (3) are respectively disposed between the two movable clamping blocks (2) of the two sets of clamping components. The side walls of the limiting blocks (3) facing the movable clamping blocks (2) on both sides are provided with a first inclined surface (4), and the side walls of the movable clamping blocks (2) facing the corresponding limiting blocks (3) are provided with a second inclined surface (5) that is adapted to fit the first inclined surface (4). The inner walls of the first groove (6) and the second groove (7) are provided with heat compensation pressure equalization pads (8), which are made of manganese copper-based anti-invar negative thermal expansion alloy.

2. The double-bolt pressure self-balancing grooved wire clamp according to claim 1, characterized in that: The U-shaped clamp (1) has a groove (9) corresponding to the position of the movable clamp (2) of each clamping component, and the bottom of the movable clamp (2) has a slider (10) integrally formed to slide with the groove (9).

3. A double-bolt pressure self-balancing grooved wire clamp according to claim 2, characterized in that: Each bolt (16) fastening assembly includes a bolt (16), a second washer (15), an elastic washer, and a nut. The limiting block (3) has an axially penetrating bolt (16) mounting hole in the middle. The bolt (16) passes through the second washer (15), the groove (9), and the bolt (16) mounting hole from bottom to top, and then the elastic washer is fitted and threadedly connected to the nut.

4. A double-bolt pressure self-balancing grooved wire clamp according to claim 2, characterized in that: The lower surface of the slider (10) protrudes from the lower surface of the U-shaped clamp (1). The lower end face of the slider (10) is fixedly connected to the first pad (11) by a fastening screw (12). The radial profile dimension of the first pad (11) is greater than the groove width of the slide (9).

5. A double-bolt pressure self-balancing grooved wire clamp according to claim 4, characterized in that: The first pad (11) has a symmetrically arranged positioning block (13) integrally formed on the side surface facing the movable clamping block (2). The lower end face of the movable clamping block (2) is provided with a positioning groove (14) that matches the shape of the positioning block (13). The positioning block (13) is embedded in the positioning groove (14).

6. A double-bolt pressure self-balancing grooved wire clamp according to claim 1, characterized in that: The two first inclined surfaces (4) on both sides of the same limiting block (3) are arranged symmetrically, and the inclined surface matching structure corresponding to the two sets of clamping components is set symmetrically with the longitudinal central axis of the U-shaped clamping block (1) as the axis of symmetry.

7. A double-bolt pressure self-balancing grooved wire clamp according to claim 1, characterized in that: The heat compensation pressure equalization pad (8) is attached and fixed to the inner wall of the first groove (6) and the second groove (7), and its working surface is adapted to the outer wall contour of the cable to be clamped.

8. A double-bolt pressure self-balancing grooved wire clamp according to claim 2, characterized in that: The slider (10) can slide steplessly along the extension direction of the groove (9) to adjust the radial dimension of the wire receiving groove.

9. A double-bolt pressure self-balancing grooved wire clamp according to claim 3, characterized in that: When the bolt (16) is tightened, the locking force of the nut drives the limiting block (3) to make longitudinal feeding motion along the axial direction of the bolt (16). Through the inclined surface cooperation structure between the limiting block (3) and the moving clamp (2), the force is transferred in a different direction, and the longitudinal linear feeding motion of the limiting block (3) is converted into the horizontal lateral pushing motion of the moving clamp (2) along the slide groove (9). At the same time, through the synchronous linkage of the two sets of symmetrically arranged inclined surface cooperation structures, the clamping force of the moving clamp (2) on both sides is automatically and evenly distributed.

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