A method for producing a helical torsion-resistant full-plastic compensating chain elastomer

Abstract

The application relates to a production method of a spiral anti-torsion full-plastic compensation chain elastomer, and the specific steps comprise the following steps of S1, chain core pretreatment; S2, inner layer spiral coating: pulling the preheated metal anchor chain into an inner layer spiral coating unit, adopting eccentric rotation extrusion to make the inner layer elastomer material in a molten state spiral wave-shapedly coat the outer surface of the metal anchor chain, the spiral wave shape is embedded in the gap between the metal anchor chain, and the inner layer elastomer is spiral wave-shapedly coated on the metal anchor chain at this time; S3, fiber winding; S4, outer layer coating; and S5, shaping correction. The application has the following advantages: the inner layer spiral wave-shaped coating is formed through eccentric rotation extrusion, the spiral wave shape is embedded in the chain ring gap to form a stress dispersion structure, and a reverse fiber winding is combined to build a net-shaped anti-torsion framework, the problems of easy torsion and short fatigue life of the traditional compensation chain are solved, and excellent anti-torsion performance and operation stability are realized.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of high-end equipment manufacturing and advanced composite materials, specifically relating to a production method of a helical anti-torsion all-plastic compensating chain elastomer, which is particularly suitable for compensating chain systems of high-speed elevators, heavy-duty elevators and elevators used in marine environments. Background Technology

[0002] All-plastic compensating chains are key balancing components in high-rise elevator systems. The most common traditional all-plastic compensating chains on the market have a relatively simple basic structure, typically consisting of two layers: a central metal anchor chain that bears the tensile force, and an outer layer of elastomer directly coated with a plastic or elastomer sheath (such as PVC or TPU material) through an extrusion process. This outer sheath primarily serves to prevent corrosion, reduce collision noise between chains, and enhance the aesthetics.

[0003] The traditional production process for a double-layer all-plastic compensating chain elastomer involves the following steps: After surface cleaning (such as sandblasting or pickling), the metal anchor chain is horizontally straightened by a traction machine and fed into the fixed die head of a single-screw extruder. The central hole of the die head is coaxial with the metal anchor chain. Molten PVC or PE material is extruded in an equal-thickness annular manner, coating the outer surface of the metal anchor chain. The chain is then cooled in a water bath to solidify, resulting in the finished product. In this method, the all-plastic compensating chain elastomer is bonded to the metal anchor chain only by adhesion, without embedding itself in the gaps between the chain links. When bent, the outer side experiences tension while the inner side experiences compression, leading to severe stress concentration and a short fatigue life. Furthermore, the circular cross-section lacks guidance, making it prone to circumferential torsion, and the absence of any torsional resistance means it cannot recover after torsion.

[0004] To address the shortcomings of the double-layer structure, some improved production methods incorporate a fiber reinforcement layer. Before the metal anchor chain is extruded and coated with the outer sheath, it passes through a fiber winding machine. This winding machine uses a single rotating disc or two rotating discs in the same direction to wind polyester or glass fiber filaments onto the surface of the metal anchor chain at a specific angle. The chain then enters the extruder to coat the outer sheath. This three-layer structure has the following drawbacks: the fibers are directly wound onto the hard metal surface, resulting in a loose bond. During extrusion, the high-pressure melt easily disperses the fiber arrangement, leading to uneven distribution of the reinforcement layer; unidirectional or unidirectional winding cannot form a true mesh-like anti-torsional skeleton, limiting torsional resistance; the inner layer still lacks an elastomer buffer layer, causing fretting wear between the fibers and the metal chain ring edges, leading to breakage over long-term use; bending stress concentration; and significant residual torsional stress within the elastomer of the all-plastic compensating chain, which gradually releases during use, causing the chain to twist in a spiral shape, posing a safety hazard. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for producing a helical anti-torsion all-plastic compensating chain elastomer, effectively solving the above technical problems.

[0006] The objective of this invention is achieved through the following technical solution: a method for producing a helical anti-torsion all-plastic compensating chain elastomer, implemented using specialized production equipment. This equipment includes, in sequence, a chain core pretreatment unit, an inner helical coating unit, a fiber winding unit, an outer coating unit, and a traction machine for horizontally transporting the traction metal anchor chain. Specific steps include...

[0007] S1. Chain core pretreatment: The traction metal anchor chain passes through a plasma cleaner and an electromagnetic induction heater in sequence to remove surface oil and preheat the metal anchor chain to 80℃-120℃.

[0008] S2, Inner spiral coating: The preheated metal anchor chain is pulled into the inner spiral coating unit. An eccentric rotary extrusion method is used to coat the outer surface of the metal anchor chain with the molten inner elastomer material in a spiral waveform. The spiral waveform is embedded in the gaps between the metal anchor chains to form an axial stress dispersion structure. At this time, the metal anchor chain is spirally coated with the inner elastomer.

[0009] Among them, the eccentric rotary extrusion method is as follows: there is a preset eccentricity between the axis of the central hole of the extrusion channel and the axis of the metal anchor chain. During the extrusion process, the eccentricity rotates and swings back and forth around the axis of the metal anchor chain, so that the circumferential thickness of the extruded inner layer elastomer material on the surface of the metal anchor chain changes periodically, forming a continuous spiral waveform.

[0010] S3, Fiber winding: The metal anchor chain covered with the inner elastomer is pulled into the fiber winding station, and the fiber bundle is wound onto the surface of the inner elastomer using a reverse winding method to form a mesh anti-torsion skeleton layer.

[0011] S4. Outer Covering: The metal anchor chain with the mesh anti-torsion skeleton layer is pulled into the outer covering unit, and the outer sheath material is wrapped on the outer surface of the mesh anti-torsion skeleton layer to form a semi-finished product.

[0012] S5. Shaping and Correction: The semi-finished product from step S4 is pulled into the shaping and correction unit and heat-shaped under negative pressure. The product torsion angle is detected in real time by a visual inspection device. When the torsion deviation exceeds the set threshold, a straightening torque is applied to the semi-finished product in the opposite direction to restore the semi-finished product to axial straightness. The all-plastic compensating chain elastomer is produced on the outside of the metal anchor chain.

[0013] A further improvement of the present invention is that: the inner layer elastomer material in step S2 comprises, by weight, 60-80 parts of thermoplastic polyurethane elastomer, 10-25 parts of nitrile rubber, 5-15 parts of plasticizer, 0.5-2 parts of antioxidant, and 0.5-3 parts of lubricant, wherein the Shore A hardness of the inner layer elastomer material is 85-95;

[0014] In step S4, the outer sheath material comprises, by weight, 50-70 parts of polyvinyl chloride resin, 10-25 parts of chlorinated polyethylene, 2-5 parts of stabilizer, 10-20 parts of plasticizer, 5-15 parts of filler, and 0.5-2 parts of anti-aging agent. The Shore A hardness of the outer sheath material is 75-85.

[0015] A further improvement of the present invention is that, in step S3, the reverse winding method of the fiber bundle is as follows: two winding discs with opposite rotation directions are used for cross winding. The two winding discs are respectively arranged on both sides of the axial direction of the metal anchor chain. The rotation axes of the two winding discs are perpendicular to the traction direction of the metal anchor chain and are parallel to each other. During the winding process, the angular velocities of the two winding discs relative to the metal anchor chain are equal, so that the fiber bundle is uniformly covered on the surface of the inner elastomer layer at a winding angle of 30°-60°.

[0016] A further improvement of the present invention is that: in step S5, after the semi-finished product is heat-set, it undergoes gradient cooling treatment: the shaped semi-finished product is sequentially placed into three water tanks with progressively decreasing temperatures, the cooling water temperatures being 40°C, 25°C, and 10°C, and ultrasonic vibration is applied in the last water tank to eliminate micropores inside the outer sheath.

[0017] A further improvement of the present invention is that the chain core pretreatment unit includes a plasma cleaner and an electromagnetic induction heater arranged sequentially.

[0018] The inner spiral coating unit includes a first extruder and an eccentric rotary head assembly connected to the discharge port of the first extruder. A metal anchor chain horizontally passes through the eccentric rotary head assembly, and the eccentric rotary head assembly forms an inner layer elastomer with a spiral wave structure on the surface of the metal anchor chain.

[0019] The fiber winding unit includes a double-disc reverse winding machine, which consists of two winding discs rotating in opposite directions;

[0020] The outer coating unit includes a second extruder and a fixed die head assembly connected to the discharge port of the second extruder. The semi-finished product with a mesh anti-torsion skeleton layer horizontally penetrates the fixed die head assembly, and the fixed die head assembly forms an outer sheath on the surface of the semi-finished product.

[0021] A further improvement of the present invention is that: the eccentric rotary die head assembly includes a first die head housing and a first integral flow channel component placed inside the first die head housing. The inlet end of the first die head housing is connected to the outlet end of the first extruder. The first die head housing is movably connected to a rotary sleeve through a bearing. The rotary sleeve is cylindrical and is connected to the first integral flow channel component. The rotary sleeve has a central hole that extends axially through it. A metal anchor chain extends horizontally through the central hole. The axis of the metal anchor chain and the axis of the central hole have an eccentricity of 1-2 mm. The outside of the first die head housing has a servo motor. The servo motor is connected to the rotary sleeve through gear transmission or synchronous belt transmission and drives the rotary sleeve to reciprocate and rotate.

[0022] The metal anchor chain passes through the center hole of the rotating sleeve in a straight line. The melt is extruded from the outlet end of the first extruder to the inlet end of the first die head housing. After being diverted and merged by the first integral flow channel component, it is extruded from the annular gap between the center hole of the rotating sleeve and the metal anchor chain, and covers the outer surface of the metal anchor chain.

[0023] A further improvement of the present invention is that: the fixed die head assembly includes a second die head housing and a second integral flow channel component placed inside the second die head housing. The inlet end of the second die head housing is connected to the outlet end of the second extruder. The outlet end of the second die head housing is connected to a fixed sleeve. The fixed sleeve is cylindrical and is connected to the second integral flow channel component. The fixed sleeve has a central hole II that extends axially inside. A metal anchor chain extends horizontally through the central hole II and is coaxially arranged with the central hole II.

[0024] A further improvement of the present invention is that: both the first integral flow channel component and the second integral flow channel component include a flow divider installed at the center inside the corresponding first or second head housing. The flow divider is located directly below the inlet end of the corresponding head housing. The flow divider has a left flow channel and a right flow channel symmetrically arranged on both sides. The lower end of the flow divider has an annular confluence cavity communicating with the left and right flow channels. The annular confluence cavity is communicating with the corresponding center hole one or center hole two.

[0025] A further improvement of the present invention is that the front end of the flow divider is a conical structure, which is used to evenly divide the melt into the left flow channel and the right flow channel; the inner walls of the left flow channel and the right flow channel are respectively provided with spiral guide grooves, so that the melt generates circumferentially distributed vortices before entering the annular confluence cavity, thereby forming a uniform annular coating layer at the central hole one or central hole two.

[0026] A further improvement of the present invention is that both the rotating sleeve and the fixed sleeve have cooling channels inside their cylinder walls. The cooling channels extend spirally along the axial direction of the rotating sleeve or the fixed sleeve. One end of the cooling channel has a coolant inlet and the other end has a coolant outlet.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. This invention introduces an eccentric rotary extrusion method for the first time in the inner layer spiral coating step. A preset eccentricity exists between the central hole axis of the extrusion channel and the axis of the metal anchor chain. During extrusion, this eccentricity reciprocates around the axis of the metal anchor chain, causing the circumferential thickness of the molten inner layer elastomer material on the anchor chain surface to change periodically, thus forming a continuous spiral waveform. This waveform structure actively embeds itself into the gaps between the metal anchor chains, forming an axial stress dispersion structure. This transforms the bending load from being borne by interfacial adhesion force to being borne collaboratively by mechanical interlocking and stress dispersion. The inner layer spiral coating process of this invention not only achieves an anchoring effect structurally but also overcomes the limitation of fixed extrusion in forming axial periodic waveforms at the process method level. It provides a non-uniform thickness irregular surface with elastic buffering function for subsequent fiber winding, significantly improving the interlayer bonding strength and fatigue resistance between the all-plastic compensating chain elastomer and the metal anchor chain.

[0029] 2. The eccentric rotary die head assembly of this invention is equipped with a first integral flow channel component. This flow channel component includes a flow divider, symmetrical left and right flow channels, and an annular confluence cavity. The front end of the flow divider uniformly distributes the melt, and the inner walls of the left and right flow channels are respectively provided with spiral guide grooves, so that the melt generates a circumferentially distributed vortex before entering the annular confluence cavity, thereby forming an annular coating layer with uniform pressure and consistent thickness at the central hole of the eccentric rotary sleeve. This integral flow channel component design solves the technical problem of uneven circumferential distribution of melt under eccentric rotation conditions and avoids local material shortages or abrupt thickness changes caused by eccentric extrusion. Through the coordinated work of the rotary sleeve and the integral flow channel component, this invention enables the amplitude, wavelength, and pitch of the spiral waveform to be controlled online by adjusting the eccentricity and the oscillation frequency of the rotary sleeve, achieving precise adjustability of the waveform structure. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the special production equipment in this invention.

[0031] Figure 2 This is a cross-sectional view of the all-plastic compensation chain obtained in this invention.

[0032] Figure 3 for Figure 1 A partial structural diagram of the inner spiral coating unit.

[0033] Figure 4 for Figure 1 A partial structural diagram of the middle and outer layer covering unit.

[0034] The numbers in the diagram are: 1-Chain core pretreatment unit, 2-Inner spiral coating unit, 3-Fiber winding unit, 4-Outer coating unit, 5-Shaping and correction unit, 6-Traction machine, 7-Metal anchor chain, 8-Inner elastomer, 9-Mesh anti-torsion skeleton layer, 10-Outer sheath.

[0035] 11-Plasma cleaner; 12-Electromagnetic induction heater;

[0036] 21-First extruder; 22-Eccentric rotary die head assembly; 221-First die head housing; 222-First integral flow channel component; 223-Rotating sleeve; 224-Bearing; 225-Center hole one; 226-Servo motor; 2221-Flow divider shuttle; 2222-Left flow channel; 2223-Right flow channel; 2224-Annular manifold.

[0037] 41-Second extruder, 42-Fixed die head assembly, 421-Second die head housing, 422-Second integral flow channel component, 423-Fixed sleeve, 424-Second center hole. Detailed Implementation

[0038] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0039] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship, such as those based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] A method for producing a helical torsion-resistant all-plastic compensating chain elastomer, referring to Figure 1 , Figure 2 The process is implemented using specialized production equipment, which includes a chain core pretreatment unit 1, an inner spiral coating unit 2, a fiber winding unit 3, an outer coating unit 4, and a traction machine for horizontally transporting the metal anchor chain 7, arranged sequentially. Specific steps include...

[0041] S1. Chain core pretreatment: The traction metal anchor chain 7 passes through a plasma cleaner and an electromagnetic induction heater in sequence to remove surface oil and preheat the metal anchor chain to 80℃-120℃.

[0042] S2, Inner spiral coating: The preheated metal anchor chain is pulled into the inner spiral coating unit 2. The eccentric rotary extrusion method is used to coat the outer surface of the metal anchor chain 7 with the molten inner elastomer material in a spiral waveform. The spiral waveform is embedded in the gaps between the metal anchor chains 7 to form an axial stress dispersion structure. At this time, the metal anchor chain 7 is spirally coated with the inner elastomer 8.

[0043] Among them, the eccentric rotary extrusion method is as follows: there is a preset eccentricity between the central hole axis of the extrusion channel and the axis of the metal anchor chain 7. This eccentricity reciprocates and swings around the axis of the metal anchor chain 7 during the extrusion process, so that the circumferential thickness of the extruded inner layer elastomer material on the surface of the metal anchor chain 7 changes periodically, forming a continuous spiral waveform.

[0044] S3, Fiber winding: The metal anchor chain 7 covered with the inner elastomer 8 is pulled into the fiber winding station 3, and the fiber bundle is wound on the surface of the inner elastomer 8 by reverse winding to form a mesh anti-torsion skeleton layer 9.

[0045] S4. Outer layer covering: The metal anchor chain 7 with the mesh anti-torsion skeleton layer 9 is pulled into the outer layer covering unit 4, and the outer sheath material is covered on the outer surface of the mesh anti-torsion skeleton layer 9 to form a semi-finished product.

[0046] S5. Shaping and Correction: The semi-finished product from step S4 is pulled into the shaping and correction unit 5 and heat-shaped under negative pressure. The product torsion angle is detected in real time by a visual inspection device. When the torsion deviation exceeds the set threshold, a straightening torque is applied to the semi-finished product in the opposite direction to restore the semi-finished product to axial straightness. The all-plastic compensating chain elastomer is produced on the outside of the metal anchor chain.

[0047] In this invention, the metal anchor chain is first cleaned to remove surface oil, significantly improving surface activity and wettability, allowing the molten elastomer to adhere tightly and preventing delamination or porosity caused by oil. Preheating the metal anchor chain before the inner spiral coating serves several purposes: it prevents quenching when the low-temperature metal anchor chain contacts the high-temperature melt, which would cause the elastomer to cool rapidly, reduce fluidity, and prevent it from fully embedding into the chain link gaps to form a spiral waveform structure; preheating helps the inner elastomer maintain a longer melt flow time on the metal anchor chain surface, allowing it to continuously and uniformly fill the chain link gaps during eccentric rotary extrusion, forming a reliable mechanical interlocking and axial stress dispersion structure; preheating reduces interlayer thermal stress and lowers the internal stress caused by uneven shrinkage of the coating layer, thereby improving the torsional stability and fatigue life of the finished chain.

[0048] This invention introduces an eccentric rotary extrusion method for the first time in the inner layer spiral coating step. A predetermined eccentricity exists between the central hole axis of the extrusion channel and the axis of the metal anchor chain. During extrusion, this eccentricity reciprocates around the metal anchor chain axis, causing the circumferential thickness of the molten inner layer elastomer material on the anchor chain surface to change periodically, thus forming a continuous spiral waveform. This waveform structure actively embeds itself into the gaps between the metal anchor chains, forming an axial stress dispersion structure. This transforms the bending load from being borne by interfacial adhesion force to being borne collaboratively by mechanical interlocking and stress dispersion. The inner layer spiral coating process of this invention not only achieves an anchoring effect structurally but also overcomes the limitation of fixed extrusion in forming axial periodic waveforms at the process method level. It provides a non-uniform thickness irregular surface with elastic buffering function for subsequent fiber winding, significantly improving the interlayer bonding strength and fatigue resistance between the all-plastic compensating chain elastomer and the metal anchor chain.

[0049] The inner layer elastomer material in step S2 comprises, by weight, 60-80 parts of thermoplastic polyurethane elastomer, 10-25 parts of nitrile rubber, 5-15 parts of plasticizer, 0.5-2 parts of antioxidant, and 0.5-3 parts of lubricant, wherein the Shore A hardness of the inner layer elastomer material is 85-95;

[0050] In step S4, the outer sheath material comprises, by weight, 50-70 parts of polyvinyl chloride resin, 10-25 parts of chlorinated polyethylene, 2-5 parts of stabilizer, 10-20 parts of plasticizer, 5-15 parts of filler, and 0.5-2 parts of anti-aging agent. The Shore A hardness of the outer sheath material is 75-85.

[0051] In step S3, the reverse winding method of the fiber bundle is as follows: two winding discs with opposite rotation directions are used for cross winding. The two winding discs are arranged on both sides of the axial direction of the metal anchor chain 7. The rotation axes of the two winding discs are perpendicular to the traction direction of the metal anchor chain 7 and parallel to each other. During the winding process, the angular velocities of the two winding discs relative to the metal anchor chain 7 are equal, so that the fiber bundle is uniformly covered on the surface of the inner elastomer layer at a winding angle of 30°-60°.

[0052] This invention employs a double-disc reverse winding method, where two winding discs rotate in opposite directions with equal angular velocities, crisscrossing the fiber bundles onto the surface of the inner elastomer at a winding angle of 30°–60° to form a mesh-like anti-torsional skeleton layer. Unlike traditional unidirectional or unidirectional winding, reverse cross-winding creates orthogonal constraints on the fibers in both rotational directions, significantly improving the coating layer's resistance to circumferential shear and torque transmission. More importantly, the fibers do not directly contact the hard metal links, but are wound around the surface of the inner elastomer (Shore A hardness 85–95) with a certain degree of hardness and elasticity. This avoids fretting wear on the fibers from the metal edges, while the elastomer buffers the melt impact during the extrusion of the outer sheath, keeping the fiber arrangement uniform. The subsequent outer sheath (Shore A hardness 75–85) has a slightly lower hardness than the inner layer, forming a gradient structure of inner hardness and outer toughness, which protects the fiber layer from damage and gives the finished product good flexibility. The inner spiral waveform, the middle mesh fiber, and the outer protective sheath work together to ensure that the internal stress of the compensation chain can be dispersed and dissipated layer by layer when subjected to frequent bending and torsion, thus preventing local damage caused by stress concentration.

[0053] In step S5, the semi-finished product undergoes gradient cooling after heat setting: the set semi-finished product is sequentially placed into three water tanks with progressively decreasing temperatures, namely 40°C, 25°C, and 10°C. Ultrasonic vibration is applied in the last water tank to eliminate micropores inside the outer sheath.

[0054] This invention employs a gradient cooling process on the heat-set semi-finished product, achieving graded cooling and preventing uneven shrinkage caused by rapid cooling. The semi-finished product is initially at a high temperature; if directly subjected to rapid cooling in a low-temperature water bath, the inconsistent shrinkage rates of the outer sheath and inner elastomer can easily lead to uneven shrinkage, resulting in warping, ellipticity deviation, or internal residual stress concentration in the finished product. By sequentially passing the chain through three water baths with gradually decreasing temperatures of 40°C, 25°C, and 10°C, the chain is gradually cooled, resulting in a gentler temperature gradient between the inner and outer layers and a more coordinated shrinkage process, effectively suppressing deformation and residual stress. Furthermore, ultrasonic vibration is applied in the final 10°C water bath, generating high-frequency micro-vibrations and cavitation effects. This promotes the expulsion of tiny air bubbles remaining inside the outer sheath, significantly improving the material's density and interfacial bonding strength, preventing pores from becoming fatigue crack initiations, and enhancing the fatigue resistance and sealing / corrosion protection performance of the compensation chain during long-term bending use.

[0055] The chain core pretreatment unit 1 includes a plasma cleaner 11 and an electromagnetic induction heater 12 arranged in sequence.

[0056] The inner spiral coating unit 2 includes a first extruder 21 and an eccentric rotary head assembly 22 connected to the discharge port of the first extruder 21. The metal anchor chain 7 horizontally passes through the eccentric rotary head assembly 22, and the eccentric rotary head assembly 22 forms an inner elastic body 8 with a spiral wave structure on the surface of the metal anchor chain 7.

[0057] The fiber winding unit 3 includes a double-disc reverse winding machine, which consists of two winding discs rotating in opposite directions;

[0058] The outer coating unit 4 includes a second extruder 41 and a fixed die head assembly 42 connected to the discharge port of the second extruder 41. The semi-finished product with a mesh anti-torsion skeleton layer 9 horizontally penetrates the fixed die head assembly 42, and the fixed die head assembly 42 forms an outer sheath 10 on the surface of the semi-finished product.

[0059] Based on this embodiment, refer to Figure 3 The eccentric rotary head assembly 22 includes a first head housing 221 and a first integral flow channel component 222 placed inside the first head housing 221. The inlet end of the first head housing 221 is connected to the outlet end of the first extruder 21. The first head housing 221 is movably connected to a rotary sleeve 223 through a bearing 224. The rotary sleeve 223 is cylindrical and is connected to the first integral flow channel component 222. The rotary sleeve 223 has an axially penetrating central hole 225 inside. A metal anchor chain 7 horizontally penetrates the central hole 225. There is an eccentricity of 1-2 mm between the axis of the metal anchor chain 7 and the axis of the central hole 225. The outside of the first head housing 221 has a servo motor 226. The servo motor 226 is connected to the rotary sleeve 223 through gear transmission or synchronous belt transmission and drives the rotary sleeve 223 to reciprocate and rotate.

[0060] The metal anchor chain 7 passes straight through the center hole 225 of the rotating sleeve 223. The melt is extruded from the outlet end of the first extruder 21 to the inlet end of the first die head housing 221. After being diverted and merged by the first integral flow channel component 222, it is extruded from the annular gap between the center hole 225 of the rotating sleeve 223 and the metal anchor chain 7, and covers the outer surface of the metal anchor chain 7.

[0061] For the inner spiral coating unit, due to the eccentricity between the rotating sleeve center hole 225 and the metal anchor chain 7 and their rotational oscillation, the instantaneous outlet gap of the melt constantly changes. Without a uniform and stable melt supply, this will lead to spiral waveform distortion or uncontrolled coating thickness. The first integral flow channel component 222, through vortex premixing and annular confluence, ensures that the melt entering the eccentric rotation region has a uniform axial velocity and circumferential pressure distribution, thereby guaranteeing that the spiral waveform extruded during eccentric rotation is continuous, regular, and fully embedded in the chain link gap.

[0062] Based on this embodiment, refer to Figure 4The fixed head assembly 42 includes a second head housing 421 and a second integral flow channel component 422 placed inside the second head housing 421. The inlet end of the second head housing 421 is connected to the outlet end of the second extruder 41. A fixed sleeve 423 is connected to the outlet end of the second head housing 421. The fixed sleeve 423 is cylindrical and is connected to the second integral flow channel component 422. The fixed sleeve 423 has a central hole 424 that extends axially inside. A metal anchor chain 7 extends horizontally through the central hole 424 and is coaxially arranged with the central hole 424.

[0063] Based on this embodiment, both the first integral flow channel component 222 and the second integral flow channel component 422 include a flow divider 2221 installed at the center inside the corresponding first head housing 221 or second head housing 421. The flow divider 2221 is located directly below the inlet end of the corresponding head housing. The flow divider 2221 has a left flow channel 2222 and a right flow channel 2223 symmetrically arranged on both sides. The lower end of the flow divider 2221 has an annular confluence cavity 2224 communicating with the left flow channel 2222 and the right flow channel 2223. The annular confluence cavity 2224 is communicating with the corresponding center hole 1 225 or center hole 2 424.

[0064] Based on this embodiment, the front end of the flow divider 2221 has a conical structure, which is used to evenly divide the melt into the left flow channel 2222 and the right flow channel 2223; the inner walls of the left flow channel 2222 and the right flow channel 2223 are respectively provided with spiral guide grooves, so that the melt generates circumferentially distributed vortices before entering the annular confluence cavity, thereby forming a uniform annular coating layer at the central hole 225 or the central hole 424.

[0065] In the all-plastic compensation chain production equipment provided by this invention, both the inner spiral coating unit 2 and the outer coating unit 4 adopt a vertical extrusion method (i.e., the melt flows vertically from the extruder outlet to the surface of the metal anchor chain), and a first integral flow channel component 222 and a second integral flow channel component 422 are respectively set in the two units, the core component of which is the flow divider. The flow divider 2221 plays the following key role in the vertical extrusion method:

[0066] 1. When the melt enters the die head vertically from the extruder outlet, it first impacts the conical tip of the splitter shuttle, symmetrically dividing into two streams: a left stream and a right stream. This design avoids the uneven accumulation or eccentric flow caused by the melt directly impacting the anchor chain surface in traditional die heads, ensuring that the two melt streams maintain a high degree of consistency in flow rate and pressure, laying the foundation for subsequent annular confluence. This is particularly crucial for the inner spiral coating unit 2: because the center hole 225 of the rotating sleeve 223 has a 1-2mm eccentricity with the metal anchor chain 7 and is in a reciprocating oscillating state, uneven melt pressure after splitting will directly lead to severe circumferential fluctuations in the extruded coating thickness, making it impossible to shape the spiral waveform. The presence of the splitter shuttle 2221 ensures that even with slight fluctuations in the die head outlet pressure, the melt reaching the eccentric rotating area still has a uniform circumferential pressure distribution.

[0067] 2. The melt then enters the annular confluence cavity 2224, where the two melt streams re-merge and redistribute circumferentially, ensuring that the melt extruded from the central hole has the same flow rate, temperature, and viscosity at any angle along the circumference. For the outer sheath 4, since the metal anchor chain 7 already has an inner elastomer 8 and a mesh anti-torsion skeleton layer 9, its surface is uneven and has a woven texture. Without eddy current premixing and annular confluence, the melt will have difficulty completely filling the gaps between the fiber layers, easily leading to residual micropores or localized thinness inside the outer sheath. The flow divider 2221 and its spiral guide groove design significantly improve the melt's ability to coat irregular substrates.

[0068] Based on this embodiment, both the rotating sleeve 223 and the fixed sleeve 423 have cooling channels inside their cylinder walls. The cooling channels extend spirally along the axial direction of the rotating sleeve 223 or the fixed sleeve 423. One end of the cooling channel has a coolant inlet and the other end has a coolant outlet.

[0069] If the melt cools too quickly after being extruded from the die, the surface of the coating layer will solidify rapidly while the interior remains molten, easily leading to shrinkage cavities or internal stress. If the cooling is too slow, the coating layer will sag and deform due to gravity. The spiral cooling channel allows for precise temperature control of the rotating sleeve, ensuring the melt maintains a suitable viscosity before leaving the die and cools smoothly after demolding, thus ensuring the precise geometric dimensions of the spiral waveform or outer sheath.

[0070] Example 1

[0071] Prepare the all-plastic compensating chain elastomer according to the following steps:

[0072] S1. Chain core pretreatment: The anchor chain is preheated to 100°C by passing through a plasma cleaner and an electromagnetic induction heater in sequence.

[0073] S2. Inner Spiral Coating: The preheated anchor chain is pulled into the inner spiral coating unit; the inner elastomer material, by weight, is: 70 parts TPU, 15 parts nitrile rubber, 10 parts plasticizer, 1 part antioxidant, and 1.5 parts lubricant. The eccentricity of the eccentric rotating head is set to 1.5mm, and the reciprocating oscillation frequency of the rotating sleeve is 4Hz, so that the inner elastomer coats the anchor chain surface in a spiral waveform with a pitch of approximately 8mm and an amplitude of approximately 2mm.

[0074] S3, Fiber winding: The anchor chain covering the inner layer is pulled into the fiber winding station. Two winding discs with opposite rotation directions are used. The winding angle is 45°. The fiber bundle is 1200tex polyester fiber. The fiber is evenly wound to form a mesh anti-torsion skeleton layer.

[0075] S4. Outer Layer Coating: The semi-finished product with the skeleton layer is drawn into the outer layer coating unit; the outer sheath material, by weight, is: 60 parts PVC, 15 parts chlorinated polyethylene, 3 parts stabilizer, 15 parts plasticizer, 10 parts filler, and 1 part anti-aging agent. The outer sheath is formed by coaxial extrusion coating using a fixed die head.

[0076] S5. Shaping and Correction: The semi-finished product is pulled into the shaping and correction unit for heat shaping under a negative pressure of 0.08MPa and a temperature of 120℃. The visual inspection system monitors the torsional deviation in real time, and applies a reverse straightening torque when it exceeds 5°. Gradient cooling is then performed: the product is passed through water tanks at 40℃, 25℃, and 10℃ in sequence. Ultrasonic vibration (frequency 40kHz, power 500W) is applied in the 10℃ water tank to obtain an all-plastic compensating chain elastomer on the outside of the metal anchor chain.

[0077] Example 2

[0078] The difference from Example 1 is as follows: the preheating temperature of the metal anchor chain in step S1 is 80°C, and the inner layer elastomer material ratio is: 80 parts TPU, 10 parts nitrile rubber, 5 parts plasticizer, 0.5 parts antioxidant, and 0.5 parts lubricant; the winding angle in step S3 is 60°C; and the outer sheath material ratio is: 70 parts PVC, 10 parts chlorinated polyethylene, 2 parts stabilizer, 10 parts plasticizer, 5 parts filler, and 0.5 parts anti-aging agent.

[0079] Example 3

[0080] The difference from Example 1 is as follows: the preheating temperature of the metal anchor chain in step S1 is 120°C, and the inner layer elastomer material ratio is: 60 parts TPU, 25 parts nitrile rubber, 15 parts plasticizer, 2 parts antioxidant, and 3 parts lubricant; the winding angle in step S3 is 30°C; and the outer layer sheath material ratio is: 50 parts PVC, 25 parts chlorinated polyethylene, 5 parts stabilizer, 20 parts plasticizer, 15 parts filler, and 2 parts anti-aging agent.

[0081] Comparative Example 1

[0082] In the traditional double-layer structure of the background technology, after the metal anchor chain is sandblasted and cleaned, the outer sheath is directly extruded coaxially through the fixed machine head.

[0083] Comparative Example 2

[0084] In the background technology, the three-layer structure of the metal anchor chain is not covered with an inner spiral after sandblasting. Instead, a single winding reel is used to unidirectionally wrap the fiber bundle on the surface of the anchor chain.

[0085] The all-plastic compensation chain samples (each group of samples is 5m long, and 3 samples are taken from each group and the average value is taken) prepared in Examples 1-3 and Comparative Examples 1-2 above were tested for performance according to the following test methods.

[0086] Ultimate torsional angle test: Fix one end of the chain, apply a torque of 50 N·m to the other end, and measure the maximum torsional angle in the middle section of the chain;

[0087] Residual torsional stress test: A 5m long chain is freely suspended on a vertical support and left to stand for 24 hours. The number of natural torsional rotations per meter (rotations / m) is then measured.

[0088] Bending fatigue life test: The chain was repeatedly bent 90° (frequency 30 times / min) using a bending fatigue testing machine, and the number of bends (in 10,000 times) when the outer sheath cracked or the inner layer delaminated was recorded.

[0089] Interlayer bond strength test: Peel the inner layer elastomer along the chain axis and measure the peel force (N / cm) per unit width (1cm).

[0090] Dynamic torsional stability test: Simulate elevator operation conditions (reciprocating motion, bending radius 300mm, frequency 1Hz), and after 1 million cycles, measure the change in the circumferential torsion angle of the chain (±°).

[0091] Outer sheath porosity test: The percentage of micropore area in the cross section of the outer sheath was measured using the density method or microscopic image analysis method.

[0092] The test data is shown in the table below:

[0093] The ultimate torsional angle of Example 1 is only 14°, while that of the traditional double-layer structure (Comparative Example 1) is as high as 78°, and that of the traditional triple-layer structure (Comparative Example 2) is 48°. The solution of this invention reduces the torsional angle by 82% and 71%, respectively. At the same time, the residual torsional stress is only 0.08 turns / m, which is 95% lower than that of Comparative Example 1 and 91% lower than that of Comparative Example 2. This shows that the inner helical waveform and the reverse fiber winding work together to effectively convert the circumferential shear force into axial tensile and compressive forces and dissipate them, thus completely solving the industry problem of spontaneous torsion in finished chains.

[0094] Example 1 exhibits a bending fatigue life exceeding 2.2 million cycles, which is more than 12 times higher than Comparative Example 1 (180,000 cycles) and nearly 3 times higher than Comparative Example 2 (750,000 cycles). The axial stress dispersion structure formed by the inner spiral waveform, combined with the gradient matching design of inner hardness and outer toughness (inner layer hardness 85-95, outer layer hardness 75-85), disperses and transmits bending stress along the waveform path, avoiding interface stress concentration and significantly extending service life.

[0095] The interlayer bonding strength of Example 1 reached 265 N / cm, which is 253% higher than that of Comparative Example 1 (75 N / cm) and 130% higher than that of Comparative Example 2 (115 N / cm). This directly proves the mechanical interlocking effect generated by the active embedding of the helical waveform into the gap of the chain links, and its bonding force is far greater than that of the simple surface adhesion of the traditional structure.

[0096] The embodiment has the best performance in all aspects: the smallest ultimate torsional angle (14°), the lowest residual torsional stress (0.08 turns / m), the longest fatigue life (>2.2 million cycles), the highest interlaminar bond strength (265 N / cm), the best dynamic torsional stability (±2.5°), and the lowest outer layer porosity (0.3%). Therefore, embodiment 1 is the best embodiment.

[0097] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a helical anti-torsion all-plastic compensating chain elastomer, implemented using specialized production equipment, the equipment comprising a chain core pretreatment unit, an inner helical coating unit, a fiber winding unit, an outer coating unit, and a traction machine for horizontally transporting a traction metal anchor chain, characterized in that: The specific steps include S1. Chain core pretreatment: The traction metal anchor chain passes through a plasma cleaner and an electromagnetic induction heater in sequence to remove surface oil and preheat the metal anchor chain to 80℃-120℃. S2, Inner spiral coating: The preheated metal anchor chain is pulled into the inner spiral coating unit. An eccentric rotary extrusion method is used to coat the outer surface of the metal anchor chain with the molten inner elastomer material in a spiral waveform. The spiral waveform is embedded in the gaps between the metal anchor chains to form an axial stress dispersion structure. At this time, the metal anchor chain is spirally coated with the inner elastomer. The eccentric rotary extrusion method is as follows: there is a preset eccentricity between the axis of the central hole of the extrusion channel and the axis of the metal anchor chain. During the extrusion process, the eccentricity rotates and swings back and forth around the axis of the metal anchor chain, so that the circumferential thickness of the extruded inner layer elastomer material on the surface of the metal anchor chain changes periodically, forming a continuous spiral waveform. S3, Fiber winding: The metal anchor chain covered with the inner elastomer is pulled into the fiber winding station, and the fiber bundle is wound onto the surface of the inner elastomer using a reverse winding method to form a mesh anti-torsion skeleton layer. S4. Outer Covering: The metal anchor chain with the mesh anti-torsion skeleton layer is pulled into the outer covering unit, and the outer sheath material is wrapped on the outer surface of the mesh anti-torsion skeleton layer to form a semi-finished product. S5. Shaping and Correction: The semi-finished product from step S4 is pulled into the shaping and correction unit and heat-shaped under negative pressure. The product torsion angle is detected in real time by a visual inspection device. When the torsion deviation exceeds the set threshold, a straightening torque is applied to the semi-finished product in the opposite direction to restore the semi-finished product to axial straightness. The all-plastic compensating chain elastomer is produced on the outside of the metal anchor chain.

2. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 1, characterized in that, The inner layer elastomer material in step S2 comprises, by weight, 60-80 parts of thermoplastic polyurethane elastomer, 10-25 parts of nitrile rubber, 5-15 parts of plasticizer, 0.5-2 parts of antioxidant, and 0.5-3 parts of lubricant. The Shore A hardness of the inner layer elastomer material is 85-95. In step S4, the outer sheath material comprises, by weight, 50-70 parts of polyvinyl chloride resin, 10-25 parts of chlorinated polyethylene, 2-5 parts of stabilizer, 10-20 parts of plasticizer, 5-15 parts of filler, and 0.5-2 parts of anti-aging agent, and the Shore A hardness of the outer sheath material is 75-85.

3. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 2, characterized in that, In step S3, the reverse winding method of the fiber bundle is as follows: two winding discs with opposite rotation directions are used for cross winding. The two winding discs are arranged on both sides of the axial direction of the metal anchor chain. The rotation axes of the two winding discs are perpendicular to the traction direction of the metal anchor chain and are parallel to each other. During the winding process, the angular velocities of the two winding discs relative to the metal anchor chain are equal, so that the fiber bundle is uniformly covered on the surface of the inner elastomer layer at a winding angle of 30°-60°.

4. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 3, characterized in that, In step S5, the semi-finished product undergoes gradient cooling after heat setting: the set semi-finished product is sequentially placed into three water tanks with progressively decreasing temperatures, with cooling water temperatures of 40°C, 25°C, and 10°C. Ultrasonic vibration is applied in the last water tank to eliminate micropores inside the outer sheath.

5. A method for producing a helical anti-torsion all-plastic compensating chain elastomer according to any one of claims 1 to 4, characterized in that, The chain core pretreatment unit includes a plasma cleaner and an electromagnetic induction heater arranged in sequence. The inner spiral coating unit includes a first extruder and an eccentric rotary head assembly connected to the discharge port of the first extruder. The metal anchor chain horizontally penetrates the eccentric rotary head assembly, and the eccentric rotary head assembly forms an inner elastomer with a spiral wave structure on the surface of the metal anchor chain. The fiber winding unit includes a double-disc reverse winding machine, which consists of two winding discs rotating in opposite directions; The outer coating unit includes a second extruder and a fixed die head assembly connected to the discharge port of the second extruder. The semi-finished product with a mesh anti-torsion skeleton layer horizontally penetrates the fixed die head assembly, and the fixed die head assembly forms an outer protective sleeve on the surface of the semi-finished product.

6. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 5, characterized in that, The eccentric rotary die head assembly includes a first die head housing and a first integral flow channel component placed inside the first die head housing. The inlet end of the first die head housing is connected to the outlet end of the first extruder. A rotary sleeve is movably connected to the first die head housing via a bearing. The rotary sleeve is cylindrical and is connected to the first integral flow channel component. The rotary sleeve has an axially penetrating central hole. A metal anchor chain horizontally penetrates the central hole. There is an eccentricity of 1-2 mm between the axis of the metal anchor chain and the axis of the central hole. A servo motor is located outside the first die head housing. The servo motor is connected to the rotary sleeve via gear transmission or synchronous belt transmission and drives the rotary sleeve to reciprocate and rotate. The metal anchor chain passes through the center hole of the rotating sleeve in a straight line. The melt is extruded from the outlet end of the first extruder to the inlet end of the first die head housing. After being diverted and merged by the first integral flow channel component, it is extruded from the annular gap between the center hole of the rotating sleeve and the metal anchor chain, and covers the outer surface of the metal anchor chain.

7. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 6, characterized in that: The fixed die head assembly includes a second die head housing and a second integral flow channel component placed inside the second die head housing. The inlet end of the second die head housing is connected to the outlet end of the second extruder. A fixed sleeve is connected to the outlet end of the second die head housing. The fixed sleeve is cylindrical and is connected to the second integral flow channel component. The fixed sleeve has a central hole that extends axially through the interior. The metal anchor chain extends horizontally through the central hole and is coaxial with the central hole.

8. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 7, characterized in that: Both the first integral flow channel component and the second integral flow channel component include a flow divider installed at the center inside the corresponding first or second head housing. The flow divider is located directly below the inlet end of the corresponding head housing. The flow divider has a left flow channel and a right flow channel symmetrically arranged on both sides. The lower end of the flow divider has an annular confluence cavity communicating with the left and right flow channels. The annular confluence cavity is communicating with the corresponding center hole one or center hole two.

9. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 8, characterized in that: The front end of the flow divider is conical, which is used to evenly divide the melt into the left and right channels. The inner walls of the left and right channels are respectively provided with spiral guide grooves, so that the melt generates circumferentially distributed vortices before entering the annular confluence cavity, thereby forming a uniform annular coating layer at the central hole one or central hole two.

10. The method for producing a helical anti-torsion all-plastic compensating chain elastomer according to claim 9, characterized in that, Both the rotating sleeve and the fixed sleeve have cooling channels inside their cylinder walls. The cooling channels extend spirally along the axial direction of the rotating sleeve or the fixed sleeve. One end of the cooling channel has a coolant inlet, and the other end has a coolant outlet.

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