A chain connecting link and assembly tool

Abstract

A chain link assembly includes a link body, which comprises an independent outer foot and an outer link plate. The independent outer foot is formed by an interference fit between the outer link plate and two pins. A chain link assembly fixture includes a fixture body, which comprises a positioning seat, a clamping screw, a clamping plate, a convex rivet block, and washers. This invention relates to the field of chain drive technology. This invention enables online interference fit assembly and rivet assembly of link links, improving the uneven load distribution on both sides of the link plates. Furthermore, the shoulder design combines cylindrical and conical structures, solving the problem of uneven contact pressure within the link plate's inner hole caused by the riveting process, thus improving the chain's service life and meeting the application conditions of high-speed, heavy-load chain drive systems.

Description

Technical Field

[0001] This invention belongs to the field of chain drive technology, specifically relating to a chain connecting link and assembly tool. Background Technology

[0002] To facilitate chain installation and maintenance, the chain system industry widely adopts joint methods such as snap rings and cotter pins. The chain plates and pins at the snap rings and cotter pins have a transition or clearance fit, which allows users to install them easily, and there will be no axial displacement of the chain plates at the connection links in the short term.

[0003] Because the assembly conditions on both sides of the connecting link are different—one side is an interference fit, and the other side is a transition or clearance fit—the actual stress state of the chain plates on both sides differs. The chain plate on the interference fit side experiences significantly greater stress than the other side, which is the reason for early fatigue fracture of the chain plate at the connecting link. Simultaneously, the transition or clearance fit significantly reduces the connection strength on that side compared to a conventional chain link. Under high-speed, heavy-load alternating conditions, the connection between the chain plate and the pin is prone to loosening, causing the chain link to disintegrate or break, leading to transmission failure of the entire chain system. Therefore, the chain connecting links and assembly methods play a crucial role in the overall service life of the chain system. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention discloses a chain connecting link and assembly tool, which can realize online interference fit assembly and riveting of the connecting link, improve the uneven load-bearing phenomenon on both sides of the chain plate, and adopt a design scheme combining cylindrical and conical structure for the shoulder to solve the problem of uneven contact pressure in the inner hole of the chain plate caused by the riveting process, improve the service life of the chain, and meet the application conditions of high-speed heavy-load chain drive system.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A chain link includes a link body, wherein the link body includes an independent outer foot and an outer link plate, and the independent outer foot is formed by an interference fit between the outer link plate and two pins.

[0007] Preferably, the two ends of the pin are stepped structures, and the two stepped structures are asymmetrical. One end of the pin is cylindrical and is interference-fitted with the outer chain plate and riveted when assembled with independent outer feet. The other end of the pin is integrally formed from the inside to the outside with a cylindrical structure and a conical structure. The conical structure includes a non-exposed part on the inner side and an exposed part on the outer side. An expansion center hole is provided at the top of the exposed part.

[0008] Preferably, the relationship between the height H of the non-exposed portion and the thickness S of the outer chain plate satisfies: H = (15% - 30%) * S, and the difference between the outer diameters D1 and D2 at both ends of the non-exposed portion is 0.01-0.05 mm.

[0009] Preferably, the inner diameter of the enlarged central hole is 40%-60% of the outer diameter of the top of the exposed portion, and its height is less than the height of the conical structure.

[0010] An assembly tool for connecting chain links includes a tool body, which comprises a positioning seat, a clamping screw, a clamping plate, a convex rivet block, and a washer. The positioning seat has two threaded holes, two pin positioning holes, and a groove for coarse positioning of the outer contour of the outer link plate. The shortest distance between the two threaded holes is greater than the waist width of the outer link plate. The diameter of the two pin positioning holes is greater than the diameter of the pin end after the rivet, and the center distance between the pin positioning holes is equal to the center distance between the holes of the outer link plate. Two pin positioning holes are located in groove one, which is located between two threaded holes. The clamping plate is provided with two groove two, which are arranged opposite to the two pin positioning holes. A convex rivet block is placed in the groove two, and the inner diameter of the groove two is larger than the outer diameter of the pin shoulder. The clamping plate is also provided with two through holes that are opposite to the threaded holes one by one. Two clamping screws pass through the through holes and are screwed into the two threaded holes. The top of the clamping screws is also provided with a washer and a screwing block.

[0011] Preferably, the convex rivet block includes a retainer and a protrusion located at the end of the retainer. The retainer is engaged with the groove, and the protrusion is used in conjunction with the enlarged center hole.

[0012] A method for assembling chain links includes the following steps:

[0013] Step 1: Insert the two pins on the independent outer feet into the inner links at both ends of the chain to be connected, cover with the outer chain plate, and align the upper end of the inner hole of the outer chain plate with the shoulder of the pin.

[0014] Step 2: Position the bottom outer chain plate through groove one, place the bottom ends of the two pins into the two pin positioning holes respectively, place the convex rivet block in groove two, cover the clamping plate, position the convex rivet block in the expansion center hole, put the washers on the two clamping screws, pass them through the corresponding through holes and screw them downward into the corresponding threaded holes.

[0015] Step 3: Tighten the two clamping screws alternately. As the clamping screws rotate, the clamping plate gradually moves inward, and the upper outer chain plate also moves downward along the conical structure. During this process, the expansion center hole gradually increases through the convex rivet block. When the upper part of the outer chain plate moves to be flush with the top of the non-exposed part, the rivet head size of the pin reaches its maximum, and the upper outer chain plate and the conical structure are interference-fitted.

[0016] The beneficial effects of the chain connecting link and assembly tool of the present invention are as follows:

[0017] This invention enables online interference fit assembly of connecting links (i.e., rapid, high-quality assembly on the production line, meeting both assembly speed and quality standards), improving the stress state at the connecting links and making the stress on the entire chain more uniform (e.g., both the upper and lower outer chain plates are interference-fitted with the pins, resulting in consistent stress). The interference fit also improves the connection strength of the connecting links. The tapered structure facilitates the disassembly of the outer chain plates. While ensuring convenient chain assembly and disassembly, this invention eliminates the risk of radial rotation of the pins and outer chain plates. The cylindrical and tapered structures of the pin shoulders make the stress on the inner hole of the outer chain plate more uniform, further extending the chain's service life. Experimental verification shows that the chain link twisting error after assembly by this invention is reduced by 70%, the connection strength is increased by 130%, and the chain length accuracy after pre-tensioning is improved by 40%. Furthermore, the problems of chain link breakage and disintegration at the connection point are effectively solved in a 500-hour bench test. The wear of the pins and sleeves at the connecting links is basically the same as that of traditional assembly methods. Attached Figure Description

[0018] Figure 1 Assembly diagram of the present invention;

[0019] Figure 2 A schematic diagram of the connecting link body structure in this invention;

[0020] Figure 3 A partial structural diagram of the pin shaft in this invention;

[0021] Figure 4 A schematic diagram of the device body structure in this invention;

[0022] Figure 5 A schematic diagram of the clamping plate structure in this invention;

[0023] Figure 6 A schematic diagram of the convex rivet head block structure in this invention;

[0024] 1: Connecting link body; 1-1: Independent outer foot; 1-1-1: Pin; 1-1-1-1: Cylindrical structure; 1-1-1-2: Conical structure; 1-1-1-3: Expanding center hole; 1-2: Outer chain plate; 2: Tool body; 2-1: Positioning seat; 2-1-1: Threaded hole; 2-1-2: Pin positioning hole; 2-1-3: Groove one; 2-2: Clamping screw; 2-3: Clamping plate; 2-3-1: Groove two; 2-4: Convex rivet head block; 2-5: Washer. Detailed Implementation

[0025] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0026] Example 1

[0027] A type of chain connecting links, such as Figure 1-3 As shown, it includes a connecting link body 1, which includes an independent outer foot 1-1 and an outer link plate 1-2. The independent outer foot 1-1 is formed by an interference fit between an outer link plate 1-2 and two pins 1-1-1.

[0028] like Figure 1-3 As shown, the pin 1-1-1 has stepped structures at both ends, and the two stepped structures are asymmetrical. One end of the pin 1-1-1 is cylindrical and is press-fitted with the outer chain plate 1-2 and riveted when the independent outer foot 1-1 is assembled. The other end of the pin is integrally formed from the inside to the outside with a cylindrical structure 1-1-1-1 and a conical structure 1-1-1-2. The conical structure 1-1-1-1 includes a non-exposed part on the inner side and an exposed part on the outer side. An expansion center hole 1-1-1-3 is provided at the top of the exposed part.

[0029] like Figure 1-3 As shown, the relationship between the height H of the non-exposed portion and the thickness S of the outer link plate satisfies: H = (15% - 30%) * S, and the difference between the outer diameters D1 and D2 at both ends of the non-exposed portion is 0.01-0.05 mm. A portion of the tapered structure extends into the interior of the outer link plate after assembly, with a height of H. After riveting, the diameter of this portion will increase, becoming approximately equal to the diameter of the cylindrical structure, and the stress generated by the interference fit will also be consistent in the axial direction.

[0030] like Figure 1-3 As shown, the inner diameter of the expansion center hole 1-1-1-3 is 40%-60% of the outer diameter of the exposed part, and its height is less than the height of the conical structure 1-1-1-2. The difference between the inner and outer diameters ensures that the expansion riveting can be carried out smoothly and meet the requirements of the rivet head.

[0031] Example 2

[0032] Based on Example 1, this example further discloses:

[0033] An assembly tool for connecting chain links, such as Figure 1 , 4As shown in Figure 6, the device includes a body 2, which comprises a positioning seat 2-1, a clamping screw 2-2, a clamping plate 2-3, a convex rivet head block 2-4, and a washer 2-5. The positioning seat 2-1 has two threaded holes 2-1-1, two pin positioning holes 2-1-2, and a groove 2-1-3 for coarse positioning of the outer contour of the outer link plate. The shortest distance between the two threaded holes 2-1-1 is greater than the waist width of the outer link plate 1-2. The diameter of the two pin positioning holes 2-1-2 is greater than the diameter of the pin 1-1-1 behind the rivet head, and the center distance between the pin positioning holes 2-1-2 is equal to the center distance between the holes of the outer link plate 1-2. The pin positioning hole 2-1-2 is located in the groove 2-1-3, which is located between two threaded holes 2-1-1. The clamping plate 2-3 has two grooves 2-3-1, which are opposite to the two pin positioning holes 2-1-2. A convex rivet block 2-4 is placed in the groove 2-3-1, and the inner diameter of the groove 2-3-1 is larger than the outer diameter of the shoulder of the pin 1-1-1. The clamping plate also has two through holes that are opposite to the threaded holes. Two clamping screws pass through the through holes and are screwed into the two threaded holes. The top of the clamping screws is also equipped with a washer and a screwing block.

[0034] like Figure 1 , 4 As shown in Figure 6, the convex rivet block 2-4 includes a retainer and a protrusion located at the end of the retainer. The retainer is engaged with the groove, and the protrusion is used in conjunction with the enlarged center hole 1-1-1-3.

[0035] Example 3

[0036] Based on embodiments 1 and 2, this embodiment further discloses:

[0037] A method for assembling chain links, such as... Figure 1-6 As shown, it includes the following steps:

[0038] Step 1: Insert the two pins 1-1-1 on the independent outer foot 1-1 into the inner links at both ends of the chain to be connected, cover the outer chain plate 1-2, and align the upper end of the inner hole of the outer chain plate 1-2 with the shoulder of the pin 1-1-1.

[0039] Step 2: Position the bottom outer chain plate 1-2 through the groove 2-1-3, place the bottom ends of the two pins 1-1-1 into the two pin positioning holes 2-1-2 respectively, place the convex rivet block 2-4 in the groove 2, cover the clamping plate, position the convex rivet block 2-4 in the expansion center hole, put the washers on the two clamping screws 2-2, pass them through the corresponding through holes and screw them downward into the corresponding threaded holes 2-1-1;

[0040] Step 3: Tighten the two clamping screws 2-2 alternately. As the clamping screws 2-2 rotate, the clamping plate 2-3 gradually moves inward. The upper outer chain plate 1-2 also moves downward along the conical structure 1-1-1-2. During this process, the convex rivet block 2-4 gradually enlarges the expansion center hole 1-1-1-3. When the upper end of the outer chain plate 1-2 moves to be flush with the top of the non-exposed part, the rivet size of the pin 1-1-1 reaches its maximum, and the upper outer chain plate and the conical structure are interference-fitted.

[0041] The chain link and assembly tool proposed in this invention can easily achieve online interference fit assembly and can use the expanded center hole for riveting. The twist error of the chain link after assembly is reduced by 70%, the connection firmness is improved by 130%, the chain length accuracy after pre-tensioning is improved by 40%, and the problem of chain link breakage and disintegration failure at the connection point is effectively solved in the 500-hour bench test. The wear of the pin and sleeve at the connection link is basically the same as the wear of the traditional assembly point.

Claims

1. A chain connecting link, characterized in that: The system includes a connecting link body, which includes an independent outer foot and an outer link plate. The independent outer foot is formed by an interference fit between the outer link plate and two pins. The pin has stepped structures at both ends, and the two stepped structures are asymmetrical. One end of the pin is cylindrical and is press-fitted with the outer chain plate and riveted when assembled with independent outer feet. The other end of the pin is integrally formed from the inside to the outside with a cylindrical structure and a conical structure. The conical structure includes a non-exposed part on the inner side and an exposed part on the outer side. An expansion center hole is provided at the top of the exposed part. The relationship between the height H of the non-exposed portion and the thickness S of the outer link plate satisfies: H = (15% - 30%) * S, and the difference between the outer diameters D1 and D2 at both ends of the non-exposed portion is 0.01 - 0.05 mm; a part of the tapered structure extends into the interior of the outer link plate after assembly, and its height is H. When riveted, the diameter of this part will increase and be approximately equal to the diameter of the cylindrical structure. The stress generated by the interference fit will also be consistent in the axial direction. The inner diameter of the enlarged central hole is 40%-60% of the outer diameter of the top of the exposed portion, and its height is less than the height of the conical structure.

2. The assembly tool for connecting chain links as described in claim 1, characterized in that: The device includes a main body comprising a positioning seat, clamping screws, a clamping plate, a convex rivet head block, and washers. The positioning seat has two threaded holes, two pin positioning holes, and a groove for coarse positioning of the outer contour of the outer chain plate. The shortest distance between the two threaded holes is greater than the waist width of the outer chain plate. The diameter of the two pin positioning holes is greater than the diameter of the pin end behind the rivet head, and the center distance between the pin positioning holes is equal to the center distance between the holes of the outer chain plate. The two pin positioning holes are located in the groove, which is located between the two threaded holes. The clamping plate has two grooves, which are opposite to the two pin positioning holes. A convex rivet head block is placed in each groove, and the inner diameter of the groove is greater than the outer diameter of the pin shoulder. The clamping plate also has two through holes opposite to the threaded holes. Two clamping screws pass through the through holes and are screwed into the two threaded holes. A washer and a screwing block are also provided at the top of the clamping screws.

3. The assembly tool for connecting chain links as described in claim 2, characterized in that: The convex rivet block includes a retainer and a protrusion located at the end of the retainer. The retainer is engaged with the groove, and the protrusion is used in conjunction with the expanded center hole.

4. A method for assembling chain links, characterized in that, The assembly of a chain link as described in claim 1 and a chain link assembly device as described in claim 3 includes the following steps: Step 1: Insert the two pins on the independent outer feet into the inner links at both ends of the chain to be connected, cover with the outer chain plate, and align the upper end of the inner hole of the outer chain plate with the shoulder of the pin. Step 2: Position the bottom outer chain plate through groove one, place the bottom ends of the two pins into the two pin positioning holes respectively, place the convex rivet block in groove two, cover the clamping plate, position the convex rivet block in the expansion center hole, put the washers on the two clamping screws, pass them through the corresponding through holes and screw them downward into the corresponding threaded holes. Step 3: Tighten the two clamping screws alternately. As the clamping screws rotate, the clamping plate gradually moves inward, and the upper outer chain plate also moves downward along the conical structure. During this process, the expansion center hole gradually increases through the convex rivet block. When the upper part of the outer chain plate moves to be flush with the top of the non-exposed part, the rivet head size of the pin reaches its maximum, and the upper outer chain plate and the conical structure are interference-fitted.

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