Heavy-load closed drag chain

Abstract

The utility model discloses a heavy load type closed drag chain, which belongs to the technical field of drag chains and comprises a plurality of chain link main bodies and a plurality of joints, each joint is arranged between two adjacent chain link main bodies, each chain link main body comprises two chain plates, and the chain plates on two sides and the upper and lower ends of the joints are respectively connected through detachable cover plates. The chain plates on the two sides, the joints and the upper and lower cover plates enclose to form a cavity; buffering pieces are arranged between the connectors and the chain plates, and gaps for bending of the drag chain are formed in the bottoms of the junctions of the connectors and the chain plates. The connectors are connected with the chain plates of the two adjacent chain link bodies, the detachable cover plates are convenient to assemble and disassemble, and cables, oil pipes, gas pipes, water pipes and the like can be installed or maintained without threading; the gap at the junction of the connector and the chain plate facilitates bending of the drag chain in reciprocating motion, friction and vibration between the chain links can be reduced by means of the buffering piece, and low-noise operation is achieved. The device is simple and compact in structure, convenient and fast to assemble and disassemble, low in operation noise and suitable for high-frequency reciprocating motion scenes.

Description

Technical Field

[0001] This utility model belongs to the field of cable chain technology, and specifically relates to a heavy-duty enclosed cable chain. Background Technology

[0002] Cable chains are widely used in various mechanical equipment, playing a vital role in the industrial field. They are primarily used to protect and guide critical components such as cables, air hoses, and hydraulic lines, ensuring their stable and safe operation during equipment movement. Currently, most existing cable chains are light-duty, micro-heavy-duty, and medium-duty types, mostly employing open or semi-enclosed structures. These are not suitable for use in harsh environments and cannot meet the load requirements of heavy-duty machinery. Therefore, there is a need to develop a new type of enclosed cable chain to adapt to the operating conditions of heavy-duty machinery in harsh environments. Utility Model Content

[0003] To address the above problems, this utility model provides a heavy-duty enclosed cable chain.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A heavy-duty enclosed cable chain includes several chain link bodies and connectors at both ends. The chain link bodies are sequentially and rotatably connected end-to-end, and the connectors at both ends are rotatably connected to the chain link bodies at both ends of the cable chain. The chain link bodies and connectors are assembled structures. Each chain link body includes two opposing and parallel chain plates. The two connectors are a first connector and a second connector. The first connector includes two opposing and parallel first connecting plates, and the second connector includes two opposing and parallel second connecting plates. The tops of the two side chain plates, the first connecting plates, and the second connecting plates are connected by a detachable cover plate one, and the bottoms of the two side chain plates, the first connecting plates, and the second connecting plates are connected by a detachable cover plate two. The top cover plates of the cable chain overlap internally and externally and slide against each other. There is a gap between the top and bottom cover plates of the cable chain. The cable chain is made of reinforced engineering plastic.

[0006] Furthermore, the two ends of the cover plate one and cover plate two are respectively connected to the chain plate, the first connecting plate and the second connecting plate through a detachable connection structure. The two adjacent chain plates and the chain plates at both ends are rotatably connected to the first connecting plate and the second connecting plate through a snap-fit ​​structure.

[0007] Furthermore, the connecting structure includes a sliding groove, a slot, and a connector. The sliding groove is located on the inner side of both sides of the first and second cover plates. The slot is located in the middle of the sliding groove and extends through the first and second cover plates. The connector is correspondingly located on the inner side of the chain plate, the first connecting plate, and the second connecting plate. Both sides of the connector can cooperate with the sliding groove, and the outer side of the connector is provided with a boss that cooperates with the slot.

[0008] Furthermore, the cover plate is divided into a large arc section, a flat section, a concave section, and a small arc section along its length. The large arc section of the cover plate of the first connector faces the end of the cable chain, and the small arc section is located below the large arc section of the cover plate of the adjacent link body. The small arc section of the cover plate at the top of the first connector is located below the large arc section of the cover plate of the adjacent link body. The small arc sections of the cover plate of the link body are sequentially located below the large arc section of the cover plate of the adjacent link body. The large arc section of the cover plate of the second connector overlaps vertically with the end of the large arc section of the cover plate of the adjacent link body, and the small arc section of the cover plate of the second connector faces the end of the cable chain.

[0009] Furthermore, the second cover plate is divided into a planar segment, a concave segment, and an arc-shaped segment along its length. The planar segment of the second cover plate of the first connector faces the end of the drag chain. The arc-shaped segment of the second cover plate of the first connector is adjacent to the planar segment of the second cover plate of the adjacent link body. The arc-shaped segment of the second cover plate of the link body is adjacent to the planar segment of the second cover plate of the adjacent link body. The arc-shaped segment of the second cover plate of the second connector is adjacent to the arc-shaped segment of the adjacent link body.

[0010] Furthermore, both the inner sides of the first and second cover plates are provided with grid-shaped reinforcing ribs, the slide groove is provided at the ends of the two reinforcing ribs, the outer middle of the slide groove is provided with an auxiliary rib, and the two sides of the slide groove opening end are provided with a support plate between the edges of the first and second cover plates.

[0011] Furthermore, both ends of the chain plate are semi-circular, the ends of the first connecting plate and the second connecting plate that mate with the chain plate are semi-circular, and the ends of the first connecting plate and the second connecting plate are rectangular.

[0012] The snap-fit ​​structure includes a positioning sleeve, an outer ring that mates with it, two protrusions and an arc-shaped groove that mates with them. The two protrusions are circumferentially and symmetrically arranged on the outer side of the outer ring, and a limiting block for limiting the bending angle of the drag chain is provided between the two protrusions. The two arc-shaped grooves are circumferentially and symmetrically arranged on the outer side of the positioning sleeve, and an arc-shaped limiting groove that mates with the limiting block is provided between the two arc-shaped grooves.

[0013] The outer side of the inner end of the second connecting plate and the outer side of one end of the chain plate are both provided with concave circular recesses. The positioning sleeve is located in the middle of the recess, and the outer side of the positioning sleeve on the recess is provided with an annular groove for accommodating the outer ring. The arc-shaped limiting groove is located at the edge of the recess and at a downward angle. The inner side of the other end of the chain plate and the inner side of the inner end of the first connecting plate are both provided with concave circular recesses. The outer ring is located in the middle of the recess. The limiting block is located near the middle of the chain plate and the first connecting plate. The recesses at both ends of the chain plate are arranged alternately inside and outside.

[0014] Furthermore, the outer edge of one end of the chain plate where the outer ring is located and the first connecting plate is provided with an arc-shaped step, and the outer edge of the side wall of the sink where the positioning sleeve is located on the adjacent chain plate and the second connecting plate is provided with a limiting eave, the limiting eave extends to fit the outer surface of the side wall edge of the arc-shaped step; the part of the chain plate and the second connecting plate corresponding to the limiting eave is provided with a hollow area.

[0015] Furthermore, the chain plate is flush with the inner surfaces of the first connecting plate and the second connecting plate, and the outer rectangular ends of the first connecting plate and the second connecting plate are provided with thickened eaves protruding from their outer surfaces.

[0016] Furthermore, the main body of the chain link and the joints at both ends are made of reinforced nylon through integral injection molding.

[0017] The technological advancements achieved by this invention compared to existing technologies are as follows:

[0018] This invention connects two adjacent chain links via a connector, with the top and bottom of the two side chain plates and the connector connected by detachable cover plates. The two side chain plates, the connector, and the top and bottom cover plates form a cavity that can accommodate cables, oil pipes, air pipes, water pipes, etc. This structure facilitates installation and disassembly, allowing for the installation or maintenance of cables, oil pipes, air pipes, water pipes, etc., without the need for threading. A gap is provided at the bottom of the junction between the connector and the chain plate for the cable chain to bend, facilitating reciprocating motion. Simultaneously, a buffer between the connector and the chain plate reduces friction and vibration between chain links, achieving low-noise operation. This invention features a simple and compact structure, convenient and quick installation and disassembly, low operating noise, and is suitable for high-frequency reciprocating motion scenarios. Attached Figure Description

[0019] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0020] In the attached diagram:

[0021] Figure 1 A schematic diagram of a heavy-duty enclosed cable chain provided for an embodiment of this utility model;

[0022] Figure 2 for Figure 1 Schematic diagram of the bottom structure of a medium-to-heavy-duty enclosed cable chain;

[0023] Figure 3 for Figure 1 Schematic diagram of the outer structure of the middle cover plate 1;

[0024] Figure 4 for Figure 1 Schematic diagram of the inner structure of the middle cover plate 1;

[0025] Figure 5 for Figure 1 Schematic diagram of the outer structure of the middle cover plate II;

[0026] Figure 6 for Figure 1 Schematic diagram of the inner structure of the second middle cover plate;

[0027] Figure 7 for Figure 1 A schematic diagram of the outer structure of the first connecting plate in the middle;

[0028] Figure 8 for Figure 1 A schematic diagram of the inner structure of the first connecting plate;

[0029] Figure 9 for Figure 1 A schematic diagram of the outer structure of the second connecting plate in the middle;

[0030] Figure 10 for Figure 1 A schematic diagram of the inner structure of the second connecting plate;

[0031] Figure 11 for Figure 1 Schematic diagram of the outer structure of the middle chain plate;

[0032] Figure 12 for Figure 1 Schematic diagram of the inner structure of the middle chain plate;

[0033] In the picture:

[0034] 100 - Chain link body, 110 - Chain plate; 200 - Connector, 210 - First connector, 221 - First connecting plate, 220 - Second connector, 221 - Second connecting plate;

[0035] 1-Cover plate one; 2-Cover plate two; 3-Gap; 4-Slide groove; 5-Card groove; 6-Connector; 7-Boss; 8-Auxiliary rib; 9-Large arc section; 10-Flat section; 11-Concave section; 12-Small arc section; 13-Arc section; 14-Reinforcing rib; 15-Weight reduction hole; 16-Support plate; 17-Positioning sleeve; 18-Outer ring; 19-Protrusion; 20-Arc-shaped slide groove; 21-Limiting block; 22-Arc-shaped limiting groove; 23-Sunken platform; 24-Annular groove; 25-Arc-shaped step; 26-Limiting eaves; 27-Hollowed area; 28-Thickened eaves. Detailed Implementation

[0036] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this utility model will be described below with reference to the accompanying drawings.

[0037] This utility model provides a heavy-duty enclosed cable chain, such as Figure 1 , 2 As shown, the cable chain includes several chain link bodies 100 and connectors 200 at both ends. The chain link bodies 100 are sequentially connected end-to-end, and the connectors 200 at both ends are rotatably connected to the chain link bodies 100 at both ends of the cable chain. Both the chain link bodies 100 and the connectors 200 are assembled structures. The chain link body 100 includes two opposing and parallel chain plates 110. The two connectors 200 are respectively a first connector 210 and a second connector 220. The first connector 210 includes two opposing and parallel first connecting plates 211, and the second connector 220 includes two opposing and parallel second connecting plates 221. The chain plates 110 on both sides, the first connector 210, the second connector 220, and the second connector 220 are respectively a first connecting head 210 and a second connecting head 220. The tops of the first connecting plate 211 and the second connecting plate 221 are connected by a detachable cover plate 1, and the bottoms of the two side chain plates 110, the first connecting plate 211 and the second connecting plate 221 are connected by a detachable cover plate 2. The cover plates 1 at the top of the cable chain overlap at both ends and slide against each other. There is a gap 3 between the ends of the adjacent cover plates 2 at the bottom of the cable chain to facilitate bending of the cable chain. After bending, the edges of the adjacent cover plates 2 can overlap, which can form a closed cavity inside the cable chain, which can protect the internal cables, oil pipes, air pipes or water pipes. The cable chain is made of reinforced engineering plastic, which has good comprehensive mechanical properties and can meet the high-speed emergency stop requirements of heavy machinery.

[0038] During assembly, the two ends of cover plate 1 and cover plate 2 are respectively connected to chain plate 110, first connecting plate 211 and second connecting plate 221 via detachable connecting structures. Adjacent chain plates 110 and both end chain plates 110 are rotatably connected to the first connecting plate 211 and second connecting plate 221 via snap-fit ​​structures. This assembly structure facilitates assembly and subsequent maintenance.

[0039] In specific embodiments of this utility model, such as Figure 3-12 As shown, the connection structure includes a sliding groove 4, a slot 5, and a connector 6. The sliding groove 4 is located on the inner side of both sides of the cover plate 1 and cover plate 2. The slot 5 is located in the middle of the sliding groove 4 and extends through cover plate 1 and cover plate 2. The connector 6 is correspondingly located on the inner side of the chain plate 110, the first connecting plate 211, and the second connecting plate 221. Both sides of the connector 6 can cooperate with the sliding groove 4, and the outer side of the connector 6 has a boss 7 that cooperates with the slot 5. During assembly, the connectors at the upper and lower ends of the chain plate, the first connecting plate, and the second connecting plate can be slid into the sliding groove on cover plate 1 and cover plate 2, and the boss at the end of the connector can be slid into the slot, thus assembling the crossbeam with the chain link body, the first connector, and the second connector. Furthermore, using the above-mentioned assembly structure, it is convenient to lay cables, oil pipes, air pipes, water pipes, etc. during cable chain assembly, and it is also convenient for later maintenance of internal cables and pipelines, making the operation quick and easy.

[0040] In specific design, such as Figure 3 , 4 As shown, the cover plate 1 is divided into a large arc section 9, a flat section 10, a concave section 11, and a small arc section 12 along its length. The large arc section 9 of the cover plate 1 of the first connector 210 faces the end of the cable chain, and the small arc section 12 is located below the large arc section 9 of the cover plate 1 of the adjacent link body 100. The small arc section 12 of the cover plate 1 at the top of the first connector 210 is located below the large arc section 9 of the cover plate 1 of the adjacent link body 100. The small arc section 12 of the cover plate 1 of the link body 100 is sequentially located below the large arc section 9 of the cover plate 1 of the adjacent link body 100. The large arc section 9 of the cover plate 1 of the second connector 220 overlaps vertically with the end of the large arc section 9 of the cover plate 1 of the adjacent link body 100, and the small arc section 12 of the cover plate 1 of the second connector 220 faces the end of the cable chain. The cover plate with the above structure overlaps at the ends of adjacent chain links and at the junctions with the first and second connectors, which can achieve complete closure of the outer side of the drag chain after bending.

[0041] In specific design, such as Figure 5 , 6As shown, the cover plate 2 is divided into a planar segment 10, a concave segment 11, and an arc-shaped segment 13 along its length. The planar segment 10 of the cover plate 2 of the first connector 210 faces the end of the cable chain, and the arc-shaped segment 13 of the cover plate 2 of the first connector 210 is adjacent to the planar segment 10 of the cover plate 2 of the adjacent link body 100. The arc-shaped segment 13 of the cover plate 2 of the second connector 220 is adjacent to the arc-shaped segment 13 of the adjacent link body 100. Similarly, with the cover plate 2 using the above structure, the ends of the cover plate 2 at the junctions between adjacent link bodies and the first and second connectors can overlap, achieving complete closure of the inner surface after the cable chain bends.

[0042] Further optimize the above structure, such as Figure 4 , 6 As shown, both cover plate 1 and cover plate 2 have grid-shaped reinforcing ribs 14 on their inner sides. The sliding groove 4 is located at the ends of the two ribs of the reinforcing ribs 14. An auxiliary rib 8 is located in the middle of the outer side of the sliding groove 4. Support plates 16 are provided between the opening ends of the sliding groove 4 and the edges of cover plate 1 and cover plate 2. Specifically, the support plate of cover plate 1 facing the large arc surface is triangular, and the other support plate of cover plate 1 is elongated and extends to the small arc surface section. The support plate of cover plate 2 facing the flat section is triangular, and the other support plate of cover plate 2 is connected to the edge of the concave section. This structure improves the strength and stiffness of cover plate 1 and cover plate 2, further enhancing the strength and stiffness of the cable chain.

[0043] In specific embodiments of this utility model, such as Figure 7-12As shown, both ends of the chain plate 110 are semi-circular, and the ends of the first connecting plate 211 and the second connecting plate 221 that mate with the chain plate 110 are also semi-circular. The ends of the first connecting plate 211 and the second connecting plate 221 are both rectangular. The snap-fit ​​structure includes a positioning sleeve 17, an outer ring 18 that mates with it, two protrusions 19, and an arc-shaped groove 20 that mates with them. The two protrusions 19 are circumferentially and symmetrically arranged on the outside of the outer ring 18, and a limiting block 21 for limiting the bending angle of the drag chain is provided between the two protrusions 19. The two arc-shaped grooves 20 are circumferentially and symmetrically arranged on the outside of the positioning sleeve 17, and an arc-shaped groove that mates with the limiting block 21 is provided between the two arc-shaped grooves 20. The limiting groove 22; the outer side of the inner end of the second connecting plate 221 and the outer side of one end of the chain plate 110 are both provided with concave circular recesses 23, the positioning sleeve 17 is provided in the middle of the recesses 23, and the outer side of the positioning sleeve 17 on the recesses 23 is provided with an annular groove 24 for accommodating the outer ring 18, the arc-shaped limiting groove 22 is provided at the edge of the recesses 23 at an angle downward; the inner side of the other end of the chain plate 110 and the inner side of the inner end of the first connecting plate 211 are both provided with concave circular recesses 23, the outer ring 18 is provided in the middle of the recesses 23, and the limiting block 21 is provided near the middle of the chain plate 110 and the first connecting plate 211; the recesses 23 at both ends of the chain plate 110 are arranged alternately inside and outside. When assembling adjacent chain plates and the first connecting plate and the second connecting plate, the positioning sleeve can be inserted into the outer ring, and the outer ring is correspondingly embedded in the annular groove on the outside of the positioning sleeve. At the same time, two protrusions are placed in two arc-shaped sliding grooves, and the limiting block is placed in the arc-shaped limiting groove. During the bending process of the cable chain, the protrusions can slide in the arc-shaped sliding grooves, and the limiting block can slide in the arc-shaped limiting grooves. The arc-shaped limiting grooves are used to limit the bending angle of the cable chain, ensuring that the cable chain bends within the limited angle.

[0044] Further optimize the above structure, such as Figure 7 , 11 The outer edge of the chain plate 110 where the outer ring 18 is located and the outer edge of the first connecting plate 211 are provided with an arc-shaped step 25. The outer edge of the side wall of the countersunk platform 23 where the positioning sleeve 17 is located on the adjacent chain plate 110 and the second connecting plate 221 are provided with a limiting eave 26. The limiting eave 26 extends to fit the outer surface of the side wall edge of the arc-shaped step 25. The chain plate 110 and the second connecting plate 221 are provided with a hollow area 27 corresponding to the limiting eave 26. The limiting eave can provide auxiliary limiting for the chain plate and the second connecting plate to ensure reliable cable chain connection.

[0045] In specific manufacturing, the inner surfaces of the chain plate 110 are flush with those of the first connecting plate 211 and the second connecting plate 221 to avoid interference with internal cables and pipelines. The outer surfaces of the chain plate 110 after assembly with the first connecting plate 211 and the second connecting plate 221 remain essentially flush, ensuring a neat and aesthetically pleasing appearance. The semi-circular outer surface of the first connecting plate 211 and the chain plate 110 where the outer ring is located slightly protrudes from its adjacent surface to provide sufficient space for the snap-fit ​​structure. Furthermore, thickened convex eaves 28 protruding from the outer rectangular ends of the first connecting plate 211 and the second connecting plate 221 are provided around their outer surfaces to further enhance the strength of the connection points at both ends of the cable chain. This structure allows the cable chain to protect the internal pipelines from mechanical damage while improving the overall neatness of the equipment's appearance, making it more aesthetically pleasing.

[0046] In the manufacturing of cable chains, the main body 100 of the chain links and the joints 200 at both ends are integrally injection molded from reinforced nylon. This process facilitates mass production, and the reinforced nylon has the best comprehensive mechanical properties, enabling the cable chain to withstand high pressure and tensile loads, meeting the high-speed emergency stop requirements of heavy machinery. It also has good toughness, high elasticity, and is wear-resistant, oil-resistant, salt-resistant, and has a certain degree of acid and alkali resistance. At the same time, the cable chain is enclosed at both ends to prevent dust and block debris, making it suitable for use in harsh environments.

[0047] In addition, the cover plate 1, cover plate 2, first connecting plate, second connecting plate and chain plate are all designed with weight reduction holes 15, which can reduce material consumption and reduce the overall weight.

[0048] In summary, this utility model has the advantages of simple and compact structure, convenient and quick loading and unloading. The cable chain made of reinforced nylon material has high compressive and tensile strength, which can meet the high-speed emergency stop requirements of heavy machinery. The prefabricated structure facilitates quick assembly, facilitates the laying of cables, oil pipes, air pipes, water pipes, etc., and facilitates maintenance. The cooperation of cover plate one and cover plate two can realize the sealing of the inner cavity of the cable chain, which facilitates the protection of internal pipelines and is suitable for working in harsh environments.

[0049] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A heavy duty enclosed tow chain, characterized by: The cable chain comprises several chain link bodies and connectors at both ends. The chain link bodies are sequentially connected end-to-end, and the connectors at both ends are rotatably connected to the chain link bodies at both ends of the cable chain. The chain link bodies and connectors are assembled structures. Each chain link body includes two opposing and parallel chain plates. The two connectors are a first connector and a second connector. The first connector includes two opposing and parallel first connecting plates, and the second connector includes two opposing and parallel second connecting plates. The tops of the two side chain plates, the first connecting plates, and the second connecting plates are connected by a detachable cover plate one, and the bottoms of the two side chain plates, the first connecting plates, and the second connecting plates are connected by a detachable cover plate two. The top cover plates of the cable chain overlap internally and externally and slide against each other. There is a gap between the top and bottom cover plates of the cable chain. The cable chain is made of reinforced engineering plastic.

2. The heavy-duty enclosed towed chain as claimed in claim 1, wherein: The two ends of the cover plate one and cover plate two are respectively connected to the chain plate, the first connecting plate and the second connecting plate through a detachable connection structure. The adjacent chain plates and the chain plates at both ends are rotatably connected to the first connecting plate and the second connecting plate through a snap-fit ​​structure.

3. A heavy duty enclosed towline as claimed in claim 2 wherein: The connecting structure includes a sliding groove, a slot, and a connector. The sliding groove is located on the inner side of both sides of the first and second cover plates. The slot is located in the middle of the sliding groove and extends through the first and second cover plates. The connector is correspondingly located on the inner side of the chain plate, the first connecting plate, and the second connecting plate. Both sides of the connector can cooperate with the sliding groove, and the outer side of the connector has a boss that cooperates with the slot.

4. A heavy duty enclosed towline as claimed in claim 3 wherein: The cover plate is divided into a large arc section, a flat section, a concave section, and a small arc section along its length. The large arc section of the cover plate of the first connector faces the end of the cable chain, and the small arc section is located below the large arc section of the cover plate of the adjacent link body. The small arc section of the cover plate of the first connector is located below the large arc section of the cover plate of the adjacent link body. The small arc sections of the cover plate of the link body are sequentially located below the large arc section of the cover plate of the adjacent link body. The large arc section of the cover plate of the second connector overlaps vertically with the end of the large arc section of the cover plate of the adjacent link body, and the small arc section of the cover plate of the second connector faces the end of the cable chain.

5. A heavy duty enclosed towline as claimed in claim 4 wherein: The second cover plate is divided into a planar segment, a concave segment, and an arc segment along its length. The planar segment of the second cover plate of the first connector faces the end of the drag chain. The arc segment of the second cover plate of the first connector is adjacent to the planar segment of the second cover plate of the adjacent link body. The arc segment of the second cover plate of the link body is adjacent to the planar segment of the second cover plate of the adjacent link body. The arc segment of the second cover plate of the second connector is adjacent to the arc segment of the adjacent link body.

6. A heavy duty enclosed towed chain as claimed in claim 4, wherein: Both the inner sides of the cover plate 1 and the cover plate 2 are provided with grid-shaped reinforcing ribs. The sliding groove is located at the ends of the two reinforcing ribs. An auxiliary rib is provided in the middle of the outer side of the sliding groove. A support plate is provided between the two sides of the opening end of the sliding groove and the edges of the cover plate 1 and the cover plate 2.

7. The heavy-duty enclosed towed chain as claimed in claim 2, wherein: Both ends of the chain plate are semicircular, one end of the first connecting plate and the second connecting plate matched with the chain plate is semicircular, and the other end of the first connecting plate and the second connecting plate is rectangular. The clamping structure comprises a positioning sleeve, an outer sleeve ring matched with the positioning sleeve, two protrusions and two arc-shaped sliding grooves matched with the protrusions, the two protrusions are circumferentially and symmetrically arranged on the outer side of the outer sleeve ring, and a limiting block for limiting the bending angle of the drag chain is arranged between the two protrusions; the two arc-shaped sliding grooves are circumferentially and symmetrically arranged on the outer side of the positioning sleeve, and an arc-shaped limiting groove matched with the limiting block is arranged between the two arc-shaped sliding grooves; The outer side of the inner end of the second connecting plate and the outer side of one end of the chain plate are provided with concave circular counterbores, the positioning sleeve is arranged in the middle of the counterbores, and the outer side of the positioning sleeve on the counterbores is provided with an annular groove for accommodating the outer sleeve ring, and the arc-shaped limiting groove is arranged at the position of the downwardly inclined edge of the counterbores; the other end of the chain plate and the inner side of the inner end of the first connecting plate are provided with concave circular counterbores, the outer sleeve ring is arranged in the middle of the counterbores, and the limiting block is arranged close to the middle position of the chain plate and the first connecting plate; the counterbores at both ends of the chain plate are arranged alternately inside and outside.

8. A heavy duty enclosed towline as claimed in claim 7 wherein: The outer side edge of one end of the chain plate and the first connecting plate where the outer sleeve ring is arranged is provided with an arc-shaped step, a limiting eave corresponding to the outer side edge of the side wall of the counterbores of the positioning sleeve on the chain plate and the second connecting plate adjacent to the arc-shaped step is arranged, and the limiting eave extends to the outer surface of the side wall edge of the arc-shaped step and is attached thereto; the part of the chain plate and the second connecting plate corresponding to the limiting eave is provided with a hollow area.

9. The heavy-duty enclosed towed chain as claimed in claim 1, wherein: The inner side surfaces of the chain plate, the first connecting plate and the second connecting plate are flush, and the outer side rectangular end of the first connecting plate and the second connecting plate is provided with a thickened eave protruding from the outer surface thereof.

10. A heavy duty enclosed towline as claimed in any one of claims 1 to 9, wherein: The chain link main body and the joints at both ends thereof are integrally injection molded by using reinforced nylon.

Images