A branch box with a safety cable pull-through entry loop and method of use

Abstract

The application discloses a branch box with a safe cable anti-pulling wire inlet ring and a use method thereof, and relates to the technical field of branch boxes. The branch box comprises a branch box body and a wire inlet hole formed in the bottom of the branch box body. A wire inlet assembly is arranged in the wire inlet hole. The wire inlet assembly comprises a fixing ring, a rubber piece and a plurality of buffer pieces. The fixing ring is coaxially fixed with the wire inlet hole. The rubber piece is coaxially arranged with the fixing ring and covers the outer circumferential side of the cable. The first and second inclined surfaces on the inner circumferential side of the fixing ring are matched with the arc-shaped strip. Regardless of whether the cable is pulled outward or inward, the inclined surfaces can force the arc-shaped strip to contract radially, thereby improving the clamping force of the rubber piece on the cable. When the cable is twisted, the rubber piece can drive the plurality of buffer pieces to slide circumferentially in the fixing ring, effectively releasing the torsional stress, avoiding the accumulation of the torsional stress at the contact interface between the wire inlet ring and the cable, and prolonging the service life of the rubber piece.

Description

Technical Field

[0001] This invention relates to the field of branch box technology, and in particular to a branch box with a safety cable anti-pull inlet ring and its usage method. Background Technology

[0002] Branch boxes are important node devices in power distribution networks. They are usually equipped with inlet rings at the bottom of the box for cables to pass through, which protect and seal the cables entering the box. The most common inlet rings on the market are simple rubber rings that achieve sealing and protection through the interference fit between the rubber ring and the cable.

[0003] However, the simple rubber ring is mainly fixed to the cable by static friction. When the cable undergoes sudden axial displacement due to foundation settlement or improper external construction in the cable laying path, the elastic deformation of the rubber ring is not only insufficient to absorb the impact, but may also cause relative slippage because the rubber ring cannot hold the cable tightly. This can lead to the rubber ring being torn or falling out of the installation groove, thus losing its sealing function.

[0004] If a clamp is used to directly fix the cable to resist axial impact, although it restricts the displacement of the cable, it completely blocks the stress release path. When the foundation settles or external construction generates axial impact, due to the lack of elastic deformation, the huge tensile force will be transmitted almost rigidly to the wiring terminals inside the box, causing the electrical joint to undergo plastic deformation, loosening or even breakage, which in turn accelerates the mechanical fatigue of the cable joint and causes poor contact or short circuit accidents.

[0005] Furthermore, most existing cable entry rings are fixed installations, while cables inevitably undergo a certain degree of circumferential torsion during installation. When installers tighten cable joints or adjust cable routing, they apply torque to the cable. Fixed cable entry rings resist this torsion, causing torsional stress to accumulate at the contact interface between the cable entry ring and the cable. Over time, this can easily lead to aging and cracking of the rubber seals, and may also cause continuous torsional shear stress damage to the cable outer sheath.

[0006] To address these issues, this invention proposes a branch box with a safety cable anti-pull inlet ring and its usage method. Summary of the Invention

[0007] The purpose of this invention is to provide a branch box with a safety cable anti-pull inlet ring and its usage method, so as to solve the technical problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a branch box with a safety cable anti-pull inlet ring, comprising a branch box body and an inlet hole at its bottom, wherein an inlet assembly is provided within the inlet hole, the inlet assembly comprising: A retaining ring is fixed coaxially with the inlet hole; A rubber component, which is coaxially arranged with the retaining ring and covers the outer circumference of the cable; The buffer is provided in multiple parts and located between the rubber part and the fixing ring. The multiple buffers are evenly distributed around the center circumference of the fixing ring. When the cable is subjected to axial tension, the rubber part can drive the buffer to move along the axial direction of the cable, thereby increasing the radial clamping force of the buffer on the cable.

[0009] Preferably, the buffer includes an arc-shaped strip that matches the inner circumferential side of the fixed ring, and an arc-shaped plate that matches the rubber component is slidably connected to the arc-shaped strip. A cavity is formed between the arc-shaped plate and the arc-shaped strip, and an elastic component is disposed in the cavity.

[0010] Preferably, the outer circumference of the fixing ring is provided with a fixing plate fixedly connected to the branch box body, and the inner circumference of the fixing ring is provided with a first inclined surface and a second inclined surface symmetrically arranged, the included angle between the first inclined surface and the second inclined surface is an obtuse angle, a plurality of arc-shaped strips are slidably connected to the fixing ring, and the outer circumference of each arc-shaped strip is provided with a third inclined surface and a fourth inclined surface, the third inclined surface and the fourth inclined surface matching the first inclined surface and the second inclined surface respectively, a contact edge being formed between the third inclined surface and the fourth inclined surface, and the contact edge contacting the inner circumference of the fixing ring.

[0011] Preferably, a rounded corner is formed between the first inclined surface and the second inclined surface, and in the initial state, the contact edge is located between the first inclined surface and the second inclined surface.

[0012] Preferably, the rubber component includes a rubber cylinder coaxially arranged with the inlet hole, and a plurality of annular grooves are formed on the outer circumference of the rubber cylinder, with the plurality of buffer components located in the corresponding annular grooves.

[0013] Preferably, the cavity is filled with a lubricating medium, and the arc-shaped strip is provided with a flow guiding mechanism that communicates with the cavity. When the cavity is compressed, the lubricating medium can enter between the fixed ring and the arc-shaped strip through the flow guiding mechanism.

[0014] Preferably, the flow guiding mechanism includes a plurality of flow guiding holes communicating with the cavity.

[0015] Preferably, the inner circumferential side of the rubber part is provided with a plurality of equally spaced annular strips.

[0016] Preferably, the cross-section of the plurality of annular strips is rectangular.

[0017] The present invention also provides a method of using a branch box with a safety cable pull-resistant inlet ring, comprising the following steps: S1. Coaxially fix the retaining ring inside the inlet hole; S2. Pass the cable through the rubber component so that the rubber component covers the outer circumference of the cable, and the rubber component holds the cable tightly under the pre-tightening force of the elastic component. S3. When the cable is subjected to axial tension, the rubber component drives the buffer component to move along the axial direction of the cable, causing the buffer component to contract radially and transmitting the contraction force to the rubber component, thereby increasing the radial clamping force of the rubber component on the cable. S4. When the cable is subjected to circumferential torsion, the rubber component drives multiple buffer components to slide circumferentially within the fixed ring to release the torsional stress.

[0018] The beneficial effects of this invention are: This invention utilizes the cooperation of the first and second inclined surfaces on the inner circumference of the fixing ring with the arc-shaped strip. When the cable is subjected to axial tension, it no longer relies solely on the static friction between the rubber and the cable to resist the force. Instead, it transforms the axial tension into a radial clamping force. The greater the tension, the stronger the clamping force. This not only improves the absorption effect of axial impact but also avoids the relative slippage problem caused by the weakening of the clamping force between the rubber ring and the cable due to elastic creep. Compared to rigid fixing methods, this invention avoids the rigid transmission of axial tension to the cable end and can tolerate axial movement of the cable within a certain range without converting these small displacements into shear torque on the cable joint, thus achieving a certain degree of buffer protection for the cable.

[0019] This invention utilizes the sliding engagement between the buffer component and the fixing ring to enable the rubber component to drive multiple buffer components to slide circumferentially within the fixing ring when the cable twists. This effectively releases torsional stress, prevents torsional stress from accumulating at the contact interface between the inlet ring and the cable, extends the service life of the rubber component, and protects the cable outer sheath from torsional shear stress damage. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the installation of the inlet assembly and inlet hole of the present invention.

[0022] Figure 3 This is a cross-sectional view of the incoming line assembly of the present invention.

[0023] Figure 4 for Figure 3 A magnified schematic diagram of the structure at point A in the middle.

[0024] Figure 5 This is a three-dimensional structural diagram of the inlet assembly of the present invention.

[0025] Figure 6 This is a schematic cross-sectional view of the inlet assembly of the present invention.

[0026] Figure 7 This is a schematic diagram showing the fit between the buffer component and the fixing ring of the present invention.

[0027] Figure 8 This is a schematic diagram of the structure of the buffer and flow guiding mechanism of the present invention.

[0028] The attached figures are labeled as follows: 1. Branch box body; 11. Cable inlet hole; 2. Inlet assembly; 21. Retaining ring; 211. Retaining plate; 212. First inclined surface; 213. Second inclined surface; 22. Rubber component; 23. Buffer component; 231. Arc strip; 232. Arc plate; 233. Cavity; 3. Flow guiding mechanism; 31. Flow guiding hole; 4. Circular stripe. Detailed Implementation

[0029] 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.

[0030] Example 1 Since the existing products rely mainly on static friction to fix the ordinary rubber rings to the cables, when the cables outside the branch box tend to move axially due to multiple factors such as foundation settlement and external construction disturbances, the rubber rings lack the corresponding buffer structure and cannot effectively absorb the sudden axial impact. As a result, the tensile force is directly transmitted to the cable connection inside the box in a near-rigid manner. Under long-term action, this can easily accelerate the mechanical fatigue of the joint and even cause the connection to loosen.

[0031] Furthermore, most existing cable entry rings are fixed installations, while cables inevitably undergo a certain degree of circumferential torsion during installation. When installers tighten cable joints or adjust cable routing, they apply torque to the cable. Fixed cable entry rings resist this torsion, causing torsional stress to accumulate at the contact interface between the cable entry ring and the cable. Over time, this can easily lead to aging and cracking of the rubber seals, and may also cause continuous torsional shear stress damage to the cable outer sheath.

[0032] This embodiment was invented to solve the above problems.

[0033] Please see Figures 1 to 8As shown, a branch box with a safety cable anti-pull inlet ring according to an embodiment of the present invention includes a branch box body 1 and an inlet hole 11 opened at its bottom. An inlet assembly 2 is provided in the inlet hole 11. The inlet assembly 2 includes a fixing ring 21, a rubber component 22 and a plurality of buffer components 23. The fixing ring 21 is coaxially fixed with the inlet hole 11, and the rubber component 22 is coaxially arranged with the fixing ring 21 and covers the outer circumference of the cable.

[0034] The aforementioned buffer components 23 are all located between the rubber component 22 and the fixing ring 21. The buffer components 23 are evenly distributed along the circumference of the center of the fixing ring 21, and there is a gap between two adjacent buffer components 23. When the cable is subjected to axial tension, the rubber component 22 can drive the buffer component 23 to move along the axial direction of the cable, thereby increasing the radial clamping force of the buffer component 23 on the cable.

[0035] Specifically, the aforementioned buffer 23 includes an arc-shaped strip 231 that matches the inner circumferential side of the fixing ring 21. An arc-shaped plate 232 that matches the rubber component 22 is slidably connected to the arc-shaped strip 231. A cavity 233 is formed between the arc-shaped plate 232 and the arc-shaped strip 231. An elastic element is provided in the cavity 233. In this embodiment, the elastic element is a compression spring. Multiple compression springs can be provided in the cavity 233. One end of the compression spring abuts against the arc-shaped plate 232, and the other end abuts against the arc-shaped strip 231.

[0036] A fixing plate 211 is provided on the outer circumference of the fixing ring 21, which is fixedly connected to the branch box body 1. The fixing plate 211 is fixed to the branch box body 1 by bolts or welding. A sealing gasket is also provided between the fixing plate 211 and the branch box body 1. A first inclined surface 212 and a second inclined surface 213 are symmetrically arranged on the inner circumference of the fixing ring 21. The included angle between the first inclined surface 212 and the second inclined surface 213 is an obtuse angle. Multiple arc-shaped strips 231 are slidably connected to the fixing ring 21. Each arc-shaped strip 231... The outer circumference of the ring 21 is provided with a third inclined surface and a fourth inclined surface, which are matched with the first inclined surface 212 and the second inclined surface 213 respectively. A contact edge is formed between the third inclined surface and the fourth inclined surface, and the contact edge contacts the inner circumference of the ring 21. The included angle between the third inclined surface and the fourth inclined surface is smaller than the included angle between the first inclined surface 212 and the second inclined surface 213. That is, the third inclined surface and the fourth inclined surface do not contact the first inclined surface 212 and the second inclined surface 213, and only the contact edge contacts the inner circumference of the ring 21.

[0037] A rounded corner is formed between the first inclined surface 212 and the second inclined surface 213. In the initial state, the contact edge is located between the first inclined surface 212 and the second inclined surface 213. When the arc strip 231 moves along the cable axis, the relative sliding between the contact edge and the first inclined surface 212 or the second inclined surface 213 can force the buffer 23 to contract radially. The gap between adjacent arc strips 231 provides space for radial contraction. The rounded corner and the line contact method of the contact edge reduce the frictional resistance in the initial state, so that the arc strip 231 can respond sensitively and start to slide when subjected to axial force.

[0038] The rubber component 22 includes a rubber cylinder coaxially arranged with the inlet hole 11, the inner diameter of which is smaller than the outer diameter of the cable, so that the rubber component 22 can form an interference fit with the cable in its natural state. Multiple annular grooves are provided on the outer circumference of the rubber cylinder, and multiple buffer components 23 are respectively located in the corresponding annular grooves.

[0039] The cavity 233 is filled with a lubricating medium, which is grease. The arc-shaped strip 231 is provided with a flow guiding mechanism 3 that communicates with the cavity 233. When the cavity 233 is compressed, the lubricating medium can enter between the fixed ring 21 and the arc-shaped strip 231 through the flow guiding mechanism 3. In this embodiment, the flow guiding mechanism 3 includes a plurality of flow guiding holes 31 that communicate with the cavity 233.

[0040] The inner circumference of the rubber part 22 is provided with a plurality of equally spaced annular strips 4. In this embodiment, the cross-section of the plurality of annular strips 4 is rectangular.

[0041] When in use, first align the fixing ring 21 coaxially with the inlet hole 11 of the branch box body 1 and fix it in place. Then, pass the cable through the fixing ring 21 and the rubber part 22 from the outside of the branch box. Since the inner diameter of the rubber part 22 is smaller than the outer diameter of the cable, the rubber part 22 undergoes elastic deformation and covers the outer circumference of the cable during the cable insertion process.

[0042] It is important to note that during the cable threading process, operators should be careful not to go too fast, which could cause deformation of the ring bar 4, and should try to make the inner circumference of the ring bar 4 contact the outer circumference of the cable.

[0043] Meanwhile, under the pre-tightening force of the elastic element, the arc plate 232 can press the rubber part 22 toward the cable direction, so that the rubber part 22 applies an initial radial clamping force to the cable. In the initial stage of the installation of the inlet assembly 2, grease is applied between the multiple buffer parts 23 and the inner circumference of the fixing plate 211. When the cable expands thermally during operation, the lubricating medium in the cavity 233 will flow out through the guide hole 31 under pressure and enter the inclined contact interface between the arc strip 231 and the fixing ring 21. When the cable shrinks due to cold, some of the lubricating medium will re-enter the guide hole 31 or the cavity 233 after the pressure in the cavity 233 decreases. The circulation formed in this way can provide good lubrication to the contact surface of the first inclined surface 212 and the second inclined surface 213, so that the contact edge and the inner circumference of the fixing ring 21 have a good lubrication effect in the initial state, avoiding the situation of the arc strip 231 getting stuck when starting.

[0044] Secondly, since the rubber component 22 is fixedly connected to multiple buffer components 23, and the buffer components 23 are slidably connected to the fixed ring 21, the fixed ring 21 is equivalent to a stationary ring, while the rubber component 22 and multiple buffer components 23 are equivalent to a moving ring. When the cable is subjected to circumferential torsion during installation, the rubber component 22 drives multiple buffer components 23 to slide synchronously in the circumferential direction within the fixed ring 21 to release torsional stress and prevent torsional stress from accumulating at the contact interface between the inlet ring and the cable.

[0045] When the cable outside the branch box is subjected to axial tension due to factors such as foundation settlement and external construction disturbance and has a tendency to move downward, the tension is transmitted through the cable to the rubber component 22 that is in close contact with it. Since the rubber component 22 is fixedly connected to the arc plate 232 by snap-fit, the rubber component 22 drives the arc plate 232 and the arc strip 231 to move along the axial direction of the cable. At this time, the contact edge on the outer circumference of the arc strip 231 can slide along the second inclined surface 213 on the inner circumference of the fixing ring 21, converting the axial movement of the arc strip 231 into radial contraction motion, thereby increasing the radial clamping force of the rubber component 22 on the cable. The greater the tension, the greater the radial contraction of the arc strip 231, and the greater the clamping force of the rubber component 22 on the cable, so as to achieve the wedge self-locking effect.

[0046] At the same time, when the arc-shaped strip 231 slides along the inclined surface of the fixed ring 21 and contracts radially, the cavity 233 is also compressed. The lubricating medium inside the cavity 233 flows out through the guide hole 31 under pressure, continuously lubricating the contact interface between the arc-shaped strip 231 and the fixed ring 21, ensuring the smooth sliding of the arc-shaped strip 231. In addition, the lubricating medium inside the cavity 233 can also absorb some of the impact energy, providing buffer protection for the cable.

[0047] In addition, in order to further ensure the initial lubrication effect between the contact edge and the inner circumference of the fixing ring 21, when the cable is subjected to axial tension, the cable will deform multiple ring bars 4 during the initial downward movement. The slight deformation of the ring bars 4 will also allow the lubricating medium in the cavity 233 or the guide hole 31 to enter the first inclined surface 212 or the second inclined surface 213.

[0048] In summary, this invention achieves wedge-shaped self-locking of the cable under bidirectional axial tension through the cooperation of the first inclined surface 212 and the second inclined surface 213 on the inner circumference side of the fixing ring 21 with the arc-shaped strip 231. Regardless of whether the cable is pulled outward or displaced inward, the inclined surface cooperation forces the arc-shaped strip 231 to contract radially, thereby increasing the clamping force of the rubber component 22 on the cable and providing a protective effect against pulling. At the same time, through the sliding cooperation between the buffer component 23 and the fixing ring 21, the rubber component 22 can drive multiple buffer components 23 to slide circumferentially within the fixing ring 21 when the cable is twisted, effectively releasing torsional stress, avoiding the accumulation of torsional stress at the contact interface between the inlet ring and the cable, extending the service life of the rubber component 22, and protecting the cable outer sheath from torsional shear stress damage.

[0049] In addition, by setting the guide hole 31 and the annular guide groove, the lubricating medium in the cavity 233 can automatically flow out to the inclined contact interface between the arc strip 231 and the fixed ring 21 when the cavity 233 is compressed, so as to dynamically lubricate the sliding friction, ensure the sensitivity of the arc strip 231 sliding, and ensure that the wedge self-locking mechanism can respond quickly.

[0050] Example 2 This embodiment also provides a method for using a branch box with a safety cable pull-resistant inlet ring, including the following steps: S1. Fix the fixing ring 21 coaxially inside the inlet hole 11.

[0051] S2. Pass the cable through the rubber component 22, so that the rubber component 22 covers the outer circumference of the cable, and the rubber component 22 holds the cable tightly under the pre-tightening force of the elastic component.

[0052] S3. When the cable is subjected to axial tension, the rubber component 22 drives the buffer component 23 to move along the axial direction of the cable, causing the buffer component 23 to contract radially and transmit this contraction force to the rubber component 22, thereby increasing the radial clamping force of the rubber component 22 on the cable.

[0053] S4. When the cable is subjected to circumferential torsion, the rubber component 22 drives multiple buffer components 23 to slide circumferentially within the fixed ring 21 to release the torsional stress.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A branch box with a safety cable pull-resistant inlet ring, comprising a branch box body (1) and an inlet hole (11) at its bottom, characterized in that, The inlet hole (11) is provided with an inlet assembly (2), the inlet assembly (2) comprising: A retaining ring (21) is fixed coaxially with the inlet hole (11); A rubber component (22) is coaxially arranged with the retaining ring (21) and covers the outer circumference of the cable; A buffer (23) is provided in multiple form and located between the rubber part (22) and the fixing ring (21). The buffer (23) includes an elastic element, and the multiple buffers (23) are evenly distributed around the center circumference of the fixing ring (21). When the cable is subjected to axial tension, the rubber part (22) can drive the buffer (23) to move along the axial direction of the cable, thereby increasing the radial clamping force of the buffer (23) on the cable.

2. A branch box with a safety cable pull-resistant inlet ring according to claim 1, characterized in that, The buffer (23) also includes an arc-shaped strip (231) that matches the inner circumferential side of the fixing ring (21). An arc-shaped plate (232) that matches the rubber part (22) is slidably connected to the arc-shaped strip (231). A cavity (233) is formed between the arc-shaped plate (232) and the arc-shaped strip (231). The elastic element is disposed in the cavity (233).

3. A branch box with a safety cable pull-resistant inlet ring according to claim 2, characterized in that, The outer circumference of the fixed ring (21) is provided with a fixed plate (211) that is fixedly connected to the branch box body (1). The inner circumference of the fixed ring (21) is provided with a first inclined surface (212) and a second inclined surface (213) that are symmetrically arranged. The included angle between the first inclined surface (212) and the second inclined surface (213) is an obtuse angle. The multiple arc strips (231) are slidably connected to the fixed ring (21). Each of the arc-shaped strips (231) has a third inclined surface and a fourth inclined surface on its outer circumference. The third inclined surface and the fourth inclined surface match the first inclined surface (212) and the second inclined surface (213) respectively. A contact edge is formed between the third inclined surface and the fourth inclined surface. The contact edge contacts the inner circumference of the fixing ring (21).

4. A branch box with a safety cable pull-resistant inlet ring according to claim 3, characterized in that, A rounded corner is formed between the first inclined surface (212) and the second inclined surface (213). In the initial state, the contact edge is located between the first inclined surface (212) and the second inclined surface (213).

5. A branch box with a safety cable pull-resistant inlet ring according to claim 2, characterized in that, The rubber component (22) includes a rubber cylinder coaxially arranged with the inlet hole (11). Multiple annular grooves are provided on the outer circumference of the rubber cylinder, and multiple buffer components (23) are respectively located in the corresponding annular grooves.

6. A branch box with a safety cable pull-resistant inlet ring according to claim 2, characterized in that, The cavity (233) is filled with a lubricating medium, and the arc-shaped strip (231) is provided with a flow guiding mechanism (3) that communicates with the cavity (233). When the cavity (233) is compressed, the lubricating medium can enter between the fixed ring (21) and the arc-shaped strip (231) through the flow guiding mechanism (3).

7. A branch box with a safety cable pull-resistant inlet ring according to claim 6, characterized in that, The flow guiding mechanism (3) includes a plurality of flow guiding holes (31) communicating with the cavity (233).

8. A branch box with a safety cable pull-resistant inlet ring according to claim 2, characterized in that, The inner circumference of the rubber part (22) is provided with a plurality of equally spaced annular strips (4).

9. A branch box with a safety cable pull-resistant inlet ring according to claim 8, characterized in that, The cross-sections of the multiple annular bars (4) are rectangular.

10. A method of using a branch box with a safety cable anti-pull inlet ring, applicable to the branch box with a safety cable anti-pull inlet ring as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Fix the fixing ring (21) coaxially inside the inlet hole (11); S2. Pass the cable through the rubber component (22) so that the rubber component (22) covers the outer circumference of the cable and the rubber component (22) holds the cable tightly under the pre-tightening force of the elastic component. S3. When the cable is subjected to axial tension, the rubber component (22) drives the buffer component (23) to move along the axial direction of the cable, causing the buffer component (23) to contract radially and transmit the contraction force to the rubber component (22), thereby increasing the radial clamping force of the rubber component (22) on the cable. S4. When the cable is subjected to circumferential torsion, the rubber component (22) drives multiple buffer components (23) to slide circumferentially within the fixed ring (21) to release the torsional stress.

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