Roll-pull type cable sheath structure

Abstract

The utility model relates to the technical field of electric power systems, and discloses a roll-pull type cable sheath structure, which comprises a gradual change area, a uniform area and a buckle area, and is characterized in that the buckle area comprises a buckle female head and a buckle male head; one end of the gradual change area is connected with the buckle female head, the other end of the gradual change area is connected with the uniform area, and gradual change transition of the material thickness from the buckle female head to the uniform area is achieved; one end, far away from the gradual change area, of the uniform area is connected with the buckle male head; the buckle female head is provided with a female head inlet, and the female head inlet is of a structure with the two sides expanded and the middle narrow. The buckle male head comprises a male head main buckle and a male head branch buckle, the male head main buckle is used for preventing the buckle male head from being disengaged from the female head inlet, and the male head branch buckle can be diverged after the buckle male head is inserted into the buckle female head and abuts against the interior of the buckle female head. The utility model has the advantages of compact structure, convenient installation, reliable protection, adaptation to different thermal shrinkage / non-thermal shrinkage environments and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to power system technical field especially relates to a winding and drawing formula cable sheath structure. BACKGROUND

[0002] In the field of power system operation and power transmission and distribution engineering, as the core carrier of electric energy transmission, the integrity of the insulation layer of the cable directly determines the safety and reliability of the system operation. However, during the long-term service of the cable, the skin (insulation layer) is easily damaged due to various factors: first, mechanical damage during the construction stage, such as dragging and scratching during cable laying, and extrusion and collision during bridge installation, which can cause partial damage to the insulation layer; second, environmental aging during the operation stage, such as the influence of ultraviolet radiation on outdoor cables, the cycle change of temperature and humidity, or the corrosion of corrosive gases (such as SF6 decomposition products in substations and acid and alkali steam in industrial environments) in cable trenches, which can cause the insulation layer to deteriorate and crack; third, external force damage, such as mechanical excavation during municipal construction and animal gnawing, which can all cause partial insulation failure of the cable. In most cases, especially for the completed power distribution network, cable bridge in substations or cable in deep buried cable trenches, replacing the cable requires interrupting power supply, excavating the road surface or disassembling the bridge, which is costly and affects the reliability of system power supply, so partial insulation repair and protection of damaged cables become a key operation and maintenance requirement.

[0003] Currently, the protection methods for partial insulation damage of cables in the industry are mainly divided into three categories, but all have significant technical defects, which are explained as follows.

[0004] I. Insulation tape winding protection

[0005] This method is the most basic temporary protection method, which uses the adhesion and insulation of pressure-sensitive adhesive insulation tape (such as PVC insulation tape and butyl rubber insulation tape) to cover the damaged part by winding multiple layers. Its advantages are convenient operation and low cost, which is suitable for emergency temporary protection scenarios, but it has long-term reliability problems that are difficult to avoid:

[0006] Thermal oxidative aging failure: the adhesive component of the insulation tape (such as pressure-sensitive adhesive) is easily subjected to thermal oxidative aging reaction under the action of cable operating temperature rise (usually 40-90℃, depending on the cable model) or high temperature environment, resulting in adhesion strength decay and adhesive molecule migration, and then the tape delamination occurs.

[0007] Residual pollution and insulation deterioration: the delaminated tape will form an oily adhesive residue on the cable surface, which is difficult to remove. This residue not only affects the subsequent secondary protection operation, but also easily absorbs dust and moisture, forming a local conductive channel in a humid environment, increasing the risk of creepage.

[0008] Poor protective sealing: The protective layer formed by the tape wrapping has gaps between layers, which cannot effectively block the intrusion of water vapor and corrosive media. Long-term use can easily lead to further deterioration of the cable insulation layer at the damaged point, and even cause short circuit faults.

[0009] 2. Cut open the heat shrink tubing and secure with cable ties for protection.

[0010] Heat shrink tubing is made of radiation-crosslinked polyolefin material. Its principle is to achieve radial shrinkage through heating, tightly adhering to the cable surface, originally designed as an integral cable insulation protection. When used for localized damage protection, the heat shrink tubing needs to be cut axially, slipped on, and then secured with nylon cable ties. While this method can improve protective strength to some extent, it damages the integrity of the molecular crosslinking structure of the heat shrink tubing, leading to the following core defects:

[0011] Failure of shrinkage function and risk of slippage: After the heat shrink tubing is cut, it loses its overall heat shrinkage capability and can only be fixed by the binding force of the cable tie. However, the cable tie and the heat shrink tubing are in point / line contact. When the cable is subjected to mechanical vibration (such as vibration of substation equipment operation or touch by inspection personnel) or thermal expansion and contraction, the cable tie is prone to loosening and the heat shrink tubing and the cable surface may slip relative to each other, resulting in misalignment of the protection position.

[0012] Permanent seams and foreign object intrusion: The axial seams formed after the heat shrink tubing is cut cannot be closed, becoming intrusion channels for foreign objects such as dust, water vapor, and insect excrement. Long-term accumulation can cause chemical corrosion of the cable insulation layer (such as insulation hydrolysis caused by acidic dust) or electrolytic corrosion (partial discharge caused by the conduction of foreign objects), resulting in secondary damage to the cable.

[0013] Poor installation compatibility: The binding force of the cable ties depends on the operator's experience. Excessive force will squeeze the cable insulation layer, while insufficient force will not guarantee a proper fit. Moreover, in narrow cable trays, the space for tightening the cable ties is limited, which can easily lead to improper installation.

[0014] III. Protection Combination of Insulating Tape and Cut Heat Shrink Tubing

[0015] To circumvent the shortcomings of a single protection method, some scenarios employ a combination of "first wrapping with insulating tape, then applying cut heat shrink tubing and binding with cable ties." However, this approach merely combines the shortcomings of two methods and fails to address the fundamental problem.

[0016] The problem of thermal and oxidative aging of insulating tape still exists. The adhesive tends to adhere to the cable surface, and air gaps are easily formed at the interface between the tape and the heat shrink tubing. In high humidity environments, partial discharge is likely to occur, which accelerates the deterioration of cable insulation.

[0017] The problem of gaps in the heat shrink tubing has not been eliminated, and foreign objects can still enter through the gaps. Furthermore, the presence of tape increases the gap between the heat shrink tubing and the cable, further reducing the protective seal.

[0018] IV. Existing Open-Type Insulating Sheath

[0019] To address the aforementioned issues, several open-type insulating sheaths have emerged on the market, but none of them can be adapted to localized protection scenarios for low-voltage centralized cables (such as multiple low-voltage cables laid in parallel within a cable tray). Specific shortcomings are as follows:

[0020] Rigid plastic pin-type open sheath: This type of sheath is made of rigid PVC or ABS material, and the opening is closed by inserting a plastic pin to lock it in place. The core problem is that the locking part has sharp edges, which can easily scratch the operator's hands or scrape the insulation layer of adjacent cables when installed in narrow spaces such as cable trays; moreover, the inner diameter of the sheath is fixed, making it unsuitable for low-voltage cables of different diameters, and after installation, it is prone to being too loose or too tight, affecting the insulation protection effect.

[0021] High-voltage, large-diameter cable special open sheaths: These sheaths are designed to accommodate the large diameter characteristics of high-voltage cables (such as 110kV and above). They have a large structural size and are mostly made of non-heat-shrinkable elastic materials (such as EPDM rubber). In densely laid low-voltage cable tray environments, their large size structure can easily cause mechanical interference with adjacent cables, making compact installation impossible. At the same time, the non-heat-shrinkable nature means that the fit between the sheath and the cable surface depends on the elasticity of the material. After long-term operation, the elasticity of the material decays, which can lead to relative slippage between the sheath and the cable, compromising the protective seal and failing to meet the requirements for heat-shrinkable bonding in some scenarios.

[0022] In summary, existing partial insulation protection technologies for cables have technical bottlenecks in terms of insulation stability, installation adaptability, long-term reliability, and scenario compatibility. In particular, for scenarios involving partial damage protection of already laid low-voltage centralized cables, there is a lack of a solution that is compact, easy to install, provides reliable protection, and can adapt to different environments, such as heat-shrinkable and non-heat-shrinkable. Therefore, there is an urgent need to develop a new type of retractable cable sheath structure to fill this technological gap. Utility Model Content

[0023] To address the aforementioned issues, this invention proposes a retractable cable sheath structure, which offers advantages such as compact structure, convenient installation, reliable protection, and adaptability to different environments, including heat-shrinkable and non-heat-shrinkable types.

[0024] The technical solution adopted in this utility model is as follows:

[0025] A retractable cable sheath structure includes a gradient zone, a uniform zone, and a snap-fit ​​zone. The snap-fit ​​zone includes a female snap-fit ​​connector and a male snap-fit ​​connector. One end of the gradient zone is connected to the female snap-fit ​​connector, and the other end of the gradient zone is connected to the uniform zone, achieving a gradual transition in material thickness from the female snap-fit ​​connector to the uniform zone. The end of the uniform zone away from the gradient zone is connected to the male snap-fit ​​connector. The female snap-fit ​​connector has a female snap-fit ​​inlet, which is a structure that expands on both sides and narrows in the middle. The male snap-fit ​​connector includes a main male snap-fit ​​and a secondary male snap-fit. The main male snap-fit ​​prevents the male snap-fit ​​connector from coming out of the female snap-fit ​​inlet, and the secondary male snap-fit ​​can expand after the male snap-fit ​​connector is inserted into the female snap-fit ​​connector and abut against the interior of the female snap-fit ​​connector.

[0026] Furthermore, the male head buckle has multiple buckles that are symmetrically distributed vertically and diverge in a natural state without external force.

[0027] Furthermore, during the process of inserting the male buckle into the female buckle, the male buckle is squeezed at the inlet of the female buckle and adheres to the surface of the male buckle main buckle; when the male buckle is fully inserted into the female buckle, the male buckle disengages from the squeeze and returns to its natural divergent state, and comes into contact with the inside of the female buckle.

[0028] Furthermore, when the male main buckle is subjected to external force and tends to disengage from the female buckle, the male sub-buckle can collapse in the opposite direction to the inlet of the female buckle.

[0029] Furthermore, the overall width of the male head buckle after the reverse collapse is greater than the width of the narrow middle section at the female head inlet, preventing the male head buckle from coming out.

[0030] Furthermore, the width of the narrow middle section at the female head inlet is slightly smaller than the width of the male head main buckle.

[0031] Furthermore, one end of the back of the buckle male head has a uniform structure that is smoothly connected to the uniform area.

[0032] Furthermore, the other end of the back of the male buckle has an open operating space.

[0033] Furthermore, the coiled cable sheath structure is in an inward-curled state when not in use.

[0034] Furthermore, the gradient zone and the female snap-fit ​​head are located on the outside of the inward-curled state, while the uniform zone and the male snap-fit ​​head are located on the inside of the inward-curled state.

[0035] The beneficial effects of this utility model are as follows:

[0036] 1. Multiple snap-fit ​​connection mechanisms

[0037] This utility model constructs a triple reliable connection system through optimized female head guidance, coordinated main and sub-clamping, and material toughness adaptation, achieving smooth insertion, tight connection, and anti-detachment redundancy. It breaks through the technical bottleneck of traditional open sheaths being prone to slippage and detachment. The specific description is as follows.

[0038] Female connector guide and interference fit design: The female connector inlet adopts a wedge-shaped structure with expansion on both sides and narrowness in the middle, forming a funnel-shaped guide channel. When the male connector is inserted, its position can be automatically corrected through the expansion side, avoiding the problems of difficult alignment and insertion jamming of traditional straight female connectors. At the same time, the width of the narrow part in the middle of the female connector inlet is slightly smaller than that of the male connector's main buckle. Combined with the slight compressibility of the sheath material, a radial interference fit is formed after insertion, so that there is no gap between the contact surfaces of the female and male connectors, effectively preventing dust and moisture from entering (compared to the buckle structure with a gap fit, the protective sealing performance is significantly improved).

[0039] Main latch radial limiting + sub-latch multi-directional resistance enhancement: The male main latch, as the primary anti-disengagement structure, is designed with a width that ensures it can be locked at the female outlet after insertion, achieving basic radial limiting. The male sub-latch adopts a multi-strut, naturally diverging layout. During insertion, it is squeezed against the surface of the main latch by the inner wall of the female connector (without increased insertion resistance). After insertion, it quickly returns to its diverging shape, forming multi-point contact with the inside of the female connector. On the one hand, the surface contact replaces point contact, significantly increasing frictional resistance and preventing the sheath from slipping due to cable thermal expansion and contraction or vibration. On the other hand, the diverging structure of the sub-latch ensures uniform stress on the inner wall of the female connector, avoiding structural deformation caused by local stress concentration.

[0040] Secondary anti-detachment redundancy of the clip: Even if the main clip tends to detach due to extreme external force (such as the cable being accidentally dragged), the clip will collapse in the opposite direction of the female head inlet. After the collapse, the overall width of the clip is greater than the width of the narrow part in the middle of the female head inlet, forming a mechanical lock and completely blocking the male head detachment path. Compared with the structure that only relies on the main clip, the anti-detachment reliability is improved by more than 2 times, which can effectively cope with accidental impacts, vibrations and other scenarios in cable operation and maintenance.

[0041] 2. Optimization of fit and protection

[0042] This utility model achieves the dual protection goal of no damage to the cable and high protection against external risks through optimized contact interface and reinforced external structure. It can solve the problems of secondary damage and weak protection in traditional protection methods. The specific description is as follows.

[0043] Non-destructive bonding at the cable contact interface: The inner side of the sheath in contact with the cable has a smooth, uniform surface without sharp edges or protruding structures. Combined with the inward-rolling pre-wrapping tendency, it avoids additional compression or scratching of the insulation layer at the damaged area of ​​the cable during bonding (compared to open sheaths with plastic needles, the secondary damage rate of the cable insulation layer is significantly reduced). At the same time, the uniform material thickness of the uniform area ensures that the bonding pressure is evenly distributed without local stress concentration. It can be adapted to low-voltage cables of different diameters, avoiding the problems of excessive compression of the cable or gaps caused by excessive looseness.

[0044] Structural redundancy of external mechanical protection: The outer side of the sheath features a gradient zone and thickened / protruding sections for the female and male locking heads, forming an external protective reinforcement layer. This reinforcement layer can withstand significant radial impact forces (such as tools falling and colliding inside the cable tray) without structural damage, significantly improving mechanical protection capabilities compared to traditional thin open sheaths. At the same time, the protruding sections prevent adjacent cables from directly contacting the inner contact area of ​​the sheath, reducing sheath wear caused by long-term friction and extending the protection cycle.

[0045] Long-term insulation performance: The overall structure of the sheath has no open seams (such as axial gaps after heat shrink tubing is cut), and the snap-fit ​​connection forms a closed-loop protection. Combined with the high insulation properties of the materials, it can effectively block the conductive path between the damaged cable and the outside world, ensuring the insulation safety of the cable during long-term operation.

[0046] 3. Compact Structural Design

[0047] This utility model achieves a synergistic improvement in both ease of operation and storage versatility through a pre-rolled structure design and functional partitioning integration, as detailed below.

[0048] Compact storage space: When not in use, the sheath has an inward-curling shape, which keeps the internal cavities sealed and protected, effectively avoiding deformation of the cavities caused by external pressure during storage or transportation (such as damage to the inner wall of the sheath caused by collisions with cable tray tools). At the same time, the inward-curling structure can simulate the cable winding method for storage, significantly reducing the storage volume (compared to the traditional flat open sheath, the space utilization rate is significantly improved). It is suitable for diverse storage scenarios such as substation toolboxes and cable maintenance vehicles, solving the pain points of traditional sheaths that occupy a lot of space and are inconvenient to carry.

[0049] Simplified operation: The inward roll gives the sheath a pre-wrapping tendency - no additional external force is required during use, the sheath can move towards the cable surface on its own. With the structural design of reserved operating space at the top and uniform transition at the bottom of the snap-on male head, the operator can quickly locate the squeezing point and complete the action of inserting the male head into the female head with only a single linear force. Compared with cable tie binding (which requires multiple adjustments of force and repeated tightening), the operation time is significantly shortened, especially suitable for one-handed operation scenarios in narrow spaces such as cable trays.

[0050] Structural self-protection mechanism: When rolled inward, the gradient zone is located on the outside. The material thickness gradually changes from the snap-fit ​​female head to the uniform zone, forming a gradient buffer layer on the outside. This layer can preferentially withstand external friction, collision and other mechanical actions, avoiding direct damage to the thinner uniform zone and snap-fit ​​female head, thus extending the storage and reuse life of the sheath (compared to open sheaths without a gradient zone, the storage breakage rate is significantly reduced). Attached Figure Description

[0051] Figure 1 This is a schematic diagram of a retractable cable sheath structure according to this utility model.

[0052] Figure 2 This is a schematic diagram of a snap-fit ​​male connector for a retractable cable sheath structure according to this utility model.

[0053] Figure 3 This is a schematic diagram of the unused state of a retractable cable sheath structure according to this utility model.

[0054] Attached reference numerals: 1-gradient zone, 2-snap female head, 3-female head inlet, 4-snap male head, 5-uniform zone, 6-male head main snap, 7-male head secondary snap. Detailed Implementation

[0055] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, specific embodiments are now described. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it; that is, the described embodiments are only a part of, and not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0056] like Figure 1 As shown, this embodiment provides a retractable cable sheath structure, including a gradient zone 1, a uniform zone 5, and a snap-fit ​​zone. The snap-fit ​​zone includes a female snap-fit ​​head 2 and a male snap-fit ​​head 4. One end of the gradient zone 1 is connected to the female snap-fit ​​head 2, and the other end of the gradient zone 1 is connected to the uniform zone 5, thus achieving a gradual transition in material thickness from the female snap-fit ​​head 2 to the uniform zone 5. The end of the uniform zone 5 away from the gradient zone 1 is connected to the male snap-fit ​​head 4. The female snap-fit ​​head 2 is provided with a female snap-fit ​​inlet 3, which has a structure that expands on both sides and is narrow in the middle. The male snap-fit ​​head 4 includes a male snap-fit ​​main snap 6 and a male snap-fit ​​secondary snap 7. The male snap-fit ​​main snap 6 is used to prevent the male snap-fit ​​head 4 from coming out of the female snap-fit ​​inlet 3, and the male snap-fit ​​secondary snap 7 can diverge after the male snap-fit ​​head 4 is inserted into the female snap-fit ​​head 2 and abut against the inside of the female snap-fit ​​head 2.

[0057] like Figure 2As shown, the male connector 4 adopts a structure of a main male connector 6 and a secondary male connector 7. The main male connector 6 is used to prevent it from falling out at the female connector inlet 3. However, since its width is only slightly larger than the female connector inlet 3, the secondary male connector 7 is designed. Preferably, there are multiple secondary male connector 7s, symmetrically distributed vertically, and they are in a divergent state under no external force. During the insertion of the male connector 4 into the female connector 2, the secondary male connector 7 is pressed against the surface of the main male connector 6 by the female connector inlet 3. When the male connector 4 is fully inserted into the female connector 2, the secondary male connector 7 is released from the pressure and returns to its divergent state, and then comes into contact with the inside of the female connector 2. In addition, when the male main latch 6 is subjected to external force and tends to disengage from the female latch 2, the male secondary latch 7 can collapse in the opposite direction to the inlet of the female latch 2; after the reverse collapse, the overall width of the male secondary latch 7 is greater than the width of the narrow middle part of the female inlet 3, preventing the male latch 4 from disengaging and improving the reliability of the connection.

[0058] It should be noted that the female connector 2 has an inlet 3 that expands on both sides and narrows in the middle. This design allows the male connector 4 to be inserted into the female connector 2 in a funnel shape, making insertion smoother and easier. Because the cable sheath material is tough and slightly compressible, the female connector inlet 3 is designed to be narrower, with a width slightly smaller than the male connector's main latch 6, thus increasing the latch's stability.

[0059] like Figure 3 As shown, when not in use, the cable sheath structure is in an inward-curled state. This inward-curled state has the advantages of saving space and preventing the internal cavities of the sheath from being squeezed and damaged. Simultaneously, because the female end of the sheath uses a thickness-gradient structure (i.e., gradient zone 1), placing the gradient zone 1 on the outside better protects the thinner, uniform zone 5 and the snap-fit ​​male end 4. Another advantage of this structure is that after the cable sheath is inwardly rolled, it can be coiled like a cable, greatly improving portability and providing more diverse storage options for the sheath.

[0060] When in use, this cable sheath structure, being pre-rolled inwards, maintains a wrapping effect even when the sheath is wrapped around the cable surface, significantly improving work efficiency. The sheath achieves a secure connection by engaging the male snap-fit ​​connector 4 with the female snap-fit ​​connector 2. For ease of operation, the male snap-fit ​​connector 4 is designed with a partially open upper section and a uniformly spaced lower section, allowing for easy compression and further enhancing work efficiency.

[0061] The above description is merely a preferred embodiment of this utility model. It should be understood that this utility model is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. A retractable cable sheath structure, characterized in that, It includes a gradient area (1), a uniform area (5) and a snap-fit ​​area, wherein the snap-fit ​​area includes a female snap-fit ​​head (2) and a male snap-fit ​​head (4); One end of the gradient zone (1) is connected to the female snap fastener (2), and the other end of the gradient zone (1) is connected to the uniform zone (5), thereby achieving a gradual transition in material thickness from the female snap fastener (2) to the uniform zone (5); the end of the uniform zone (5) away from the gradient zone (1) is connected to the male snap fastener (4). The female snap-fit ​​head (2) is provided with a female snap-fit ​​inlet (3), which is a structure that expands on both sides and narrows in the middle; the male snap-fit ​​head (4) includes a male snap-fit ​​main snap (6) and a male snap-fit ​​secondary snap (7). The male snap-fit ​​main snap (6) is used to prevent the male snap-fit ​​head (4) from coming out of the female snap-fit ​​inlet (3). The male snap-fit ​​secondary snap (7) can diverge after the male snap-fit ​​head (4) is inserted into the female snap-fit ​​head (2) and abut against the inside of the female snap-fit ​​head (2).

2. The reel-type cable sheath structure according to claim 1, characterized in that, The male head buckle (7) has multiple buckles that are symmetrically distributed vertically and diverge in a natural state without external force.

3. The reel-type cable sheath structure according to claim 2, characterized in that, During the process of inserting the male buckle (4) into the female buckle (2), the male buckle (7) is pressed against the surface of the male main buckle (6) by the inlet (3) of the female buckle; when the male buckle (4) is fully inserted into the female buckle (2), the male buckle (7) is released from the pressure and returns to its natural divergent state, and comes into contact with the inside of the female buckle (2).

4. The reel-type cable sheath structure according to claim 1, characterized in that, When the male head main buckle (6) is subjected to external force and tends to disengage from the buckle female head (2), the male head sub-buckle (7) can collapse in the opposite direction to the inlet direction of the buckle female head (2).

5. A reel-type cable sheath structure according to claim 4, characterized in that, The overall width of the male head buckle (7) after the reverse collapse is greater than the width of the narrow middle part of the female head inlet (3), preventing the male head buckle (4) from coming out.

6. The reel-type cable sheath structure according to claim 1, characterized in that, The width of the narrow middle section of the female head inlet (3) is slightly smaller than the width of the male head main buckle (6).

7. The reel-type cable sheath structure according to claim 1, characterized in that, The back end of the buckle male head (4) is a uniform structure that is smoothly connected to the uniform area (5).

8. A reel-type cable sheath structure according to claim 7, characterized in that, The other end of the back of the buckle male head (4) has an open operating space.

9. A reel-type cable sheath structure according to any one of claims 1-8, characterized in that, The coiled cable sheath structure is in an inward-curled state when not in use.

10. A reel-type cable sheath structure according to claim 9, characterized in that, The gradient zone (1) and the female snap-fit ​​head (2) are located on the outside of the inward-curled state, while the uniform zone (5) and the male snap-fit ​​head (4) are located on the inside of the inward-curled state.

Images