Automatic edge closing device in the process of net blanket flocking

Abstract

This application relates to the field of papermaking machinery and textile composite material processing technology, and discloses an automatic edge-closing device during the flocking process of a wire mesh. The device includes a three-dimensional gradient spiral guide groove, an active clamping roller, a yarn-pulling needle roller assembly, an elastic pre-pressure roller, and a wave-tooth pressure-locking roller arranged sequentially along the direction of the wire mesh travel. The three-dimensional gradient spiral guide groove folds the edge of the wire mesh from a flat state to 180°, forming a double-layered overlapping edge; the active clamping roller maintains a tight fit between the two layers; the yarn-pulling needle roller assembly includes upper and lower opposing needle rollers, with smooth, barbed blunt-tipped yarn-pulling needles distributed on the rim of the needle rollers. Through the bidirectional pushing mechanism of the upper and lower opposing blunt-tipped yarn-pulling needles, the yarn segments of the upper base mesh are pushed into the lower mesh openings, and the yarn segments of the lower base mesh are pushed into the upper mesh openings, forming a bidirectional interlocking layered structure. The connection is achieved by utilizing the mechanical constraints of the yarns of the base mesh itself and the edges of the mesh openings, eliminating the need for external media such as glue or sewing threads throughout the process.

Description

Technical Field

[0001] This invention relates to the field of papermaking machinery and textile composite material processing technology, specifically to an automatic edge-closing device during the flocking process of a mesh blanket. Background Technology

[0002] Flocked dryer wire is a key consumable in the drying section of a paper machine, used to support wet paper sheets as they pass through the drying cylinder assembly for dehydration and drying. This type of dryer wire uses polyester weaving or spiral winding processes to form a high-strength wire skeleton, and then needle-punches high-temperature resistant short fibers into the surface of the wire, creating a multi-layered composite fabric. The high-aperture mesh structure of the dryer wire ensures breathable dehydration performance, while the flocked fiber layers provide soft support and anti-slip properties. The dryer wire operates in a closed loop on the paper machine, bearing significant tension and repeated bending stress, requiring stringent edge bonding strength and durability.

[0003] After the dry wire is produced, its side edges need to be sealed by folding and securing them inwards to form a closed boundary, preventing the edges from unraveling or the yarn from pulling out. The quality of the edge sealing directly affects the service life of the dry wire and the quality of paper production. Traditional sealing methods mainly rely on glue bonding or sewing, but both methods have inherent defects that are difficult to overcome in practical applications.

[0004] Adhesive bonding achieves adhesion by applying hot melt adhesive or epoxy resin between the folded double-layer edges. The adhesive penetrates into the mesh and fiber gaps of the dry wire, and after curing, bonds the two layers together. This method seems simple and direct, but the presence of adhesive fundamentally alters the air permeability of the dry wire. The open area ratio of papermaking dry wire is typically 40%-70%, with large and regular mesh openings. This high open area ratio ensures the air permeability and dehydration function of the dry wire during the papermaking process. After the adhesive fills the mesh, the open area ratio at the closing edge decreases significantly or even becomes completely blocked. The air permeability in this area is lost, resulting in uneven dehydration of the wet paper sheet as it passes through this area, with locally higher moisture content and reduced drying efficiency. A more serious problem is that the hardening effect of the adhesive on the flocked fiber layer causes the closing edge to lose its flexibility, becoming stiff and prone to breakage. During repeated bending and running of the dry wire, the hardened edge becomes a stress concentration point, accelerating fatigue failure and shortening the service life of the dry wire.

[0005] The stitching method uses high-strength sewing thread to bind and sew the edges of the folded double layers. The thread passes through the double-layer dry wire and is secured by a mechanical interlocking stitch. The stitch strength depends on the tensile strength of the thread itself and the density of the stitch, theoretically achieving high bonding strength. However, the presence of the thread introduces another fatal flaw. After stitching, the closed edge forms a raised stitch track. This raised area contacts the wet paper surface during dry wire operation, pressing out striped marks on the paper surface, known in the papermaking industry as blanket marks. Blanket marks are a serious defect in paper quality, reducing the paper's flatness and surface smoothness, leading to downgrading or scrapping of the finished paper. For high-grade printing paper, coated paper, and other paper types with strict surface quality requirements, blanket marks are particularly prominent, directly affecting the product's market competitiveness. Stitching also suffers from low operational efficiency. The stitching process requires manual operation with machine stoppage or the use of complex automatic sewing equipment, resulting in a slow production cycle, high labor costs, and the risk of thread wear and breakage over long-term use, requiring frequent maintenance.

[0006] From a technical perspective, both adhesive bonding and stitching share the problem of relying on external media for adhesion. As foreign substances with properties completely different from the drynet material, the introduction of adhesive and stitching inevitably interferes with the original performance of the drynet. Adhesive clogs the mesh and hardens the fibers, while stitching protrudes and forms blanket marks. These negative effects are inherent to the external media and cannot be fundamentally eliminated by improving the adhesive formulation or optimizing the stitching process. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an automatic edge-closing device during the flocking process of a mesh blanket. This device solves the problems of glue bonding clogging the dry mesh and reducing air permeability, hardening the flocking fiber layer and causing edge brittleness, and sewing methods producing raised seams that form blanket marks on the paper surface, resulting in low operating efficiency and easy wear and breakage of the seams.

[0008] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides an automatic edge-closing device for the flocking process of papermaking flocking dry wire, comprising a three-dimensional gradient spiral guide groove, a yarn-pulling needle roller assembly, and a wave-tooth pressure-locking roller arranged sequentially along the traveling direction of the dry wire. The three-dimensional gradient spiral guide groove is used to fold the edge of the dry wire by 180°, so that the two layers of dry wire are relatively close together to form a double-layered overlapping edge. The cross-section of the guide groove is a three-segment gradient along the traveling direction of the dry wire: the inlet section is a horizontal straight plate with the same width as the edge of the dry wire; the middle section is an L-shape guiding the folding of the dry wire edge; and the outlet section is a C-shape pressing the edge of the dry wire to 180°. After folding, the flocked fiber layer faces outward, and the mesh surfaces of the two layers of dry wire are relatively close together to form a double-layered overlapping edge.

[0009] Preferably, the yarn-drawing needle roller assembly includes two needle rollers positioned vertically opposite each other, with blunt-tipped yarn-drawing needles radially distributed on the rims of the needle rollers. The blunt-tipped yarn-drawing needles are rigid metal needles with smooth surfaces and no barbs, and their tips are blunt-tipped or forked. The blunt-tipped yarn-drawing needles of the upper needle roller penetrate the double-layered overlapping edge from top to bottom, pushing the yarn segment at the mesh node of the upper dry web downwards to pass through the contact interface of the two dry webs and enter the mesh of the lower dry web; the blunt-tipped yarn-drawing needles of the lower needle roller penetrate the double-layered overlapping edge from bottom to top, pushing the yarn segment at the mesh node of the lower dry web upwards to pass through the contact interface of the two dry webs and enter the mesh of the upper dry web. When the blunt-tipped yarn-pulling needle retracts, because the needle surface is smooth and has no barbs, it does not engage the yarn segment. The upper yarn segment remains in the lower dry mesh and is supported and constrained laterally by the edge of the lower mesh, while the lower yarn segment remains in the upper dry mesh and is supported and constrained laterally by the edge of the upper mesh, forming a two-way interlocking point.

[0010] This invention utilizes a bidirectional pushing mechanism with opposing blunt-tipped yarn-pulling needles to achieve bidirectional interlocking and layer-by-layer bonding without external media. Unlike traditional needle punching methods that rely on barbs to engage fibers, this invention employs smooth, barbless blunt-tipped yarn-pulling needles. Through a pushing rather than hooking mechanism, yarn segments are pushed from one layer of dry web into the mesh of the opposite layer. The upper roller pushes the upper layer yarn into the lower layer, and the lower roller pushes the lower layer yarn into the upper layer, forming a bidirectional interlocking structure: the upper and lower layers of yarn interweave at the nodes, with each layer having both the yarn segments pushed into the other providing a locking mechanism and the mesh of the receiving yarn providing constraint, creating a three-dimensional mechanical connection similar to weaving. Because the blunt-tipped needles are smooth, the yarn segments are not pulled back by the needles when the needles withdraw, naturally remaining within the mesh of the opposite layer, fundamentally eliminating the material slippage problem of traditional barb needles.

[0011] To address the high open area ratio of paper flocking wire, this invention establishes kinematic constraints for rotational puncture. The roller diameter of the needle roller, the needle length of the blunt-tipped yarn-pulling needle, and the window angle of the working window are matched to ensure that the lateral displacement of the blunt-tipped yarn-pulling needle tip within the working window relative to the wire is less than the size of a single mesh opening. The blunt-tipped yarn-pulling needle completes the penetration and pushing action of the yarn segment within the same mesh opening; lateral sliding is accommodated by the mesh opening gaps, without crossing the yarn or tearing the mesh.

[0012] Preferably, the corrugated toothed pressure-locking roller comprises two pressure rollers positioned vertically opposite each other with complementary corrugated teeth on their surfaces, used to apply plastic pressure lock to the bidirectional interlocking points. The trough pitch of the corrugated toothed pressure-locking roller is equal to the needle-punching pitch formed by the blunt-tipped yarn-drawing needle in the direction of the dry web's travel. The corrugated toothed pressure-locking roller and the needle roller are connected by a synchronous transmission mechanism containing a phase coupling. While maintaining a constant transmission ratio, the phase angle between the two is adjusted so that each bidirectional interlocking point falls precisely into the trough position of the corrugated toothed pressure-locking roller as it moves forward with the dry web.

[0013] When the two pressure rollers mesh, the bidirectional interlocking point located at the trough is subjected to concentrated pressure from the crests on both sides. Since the papermaking dry wire has a mesh structure, the crests actually act on the mesh nodes. The bidirectional interlocking point simultaneously involves yarn segments interlacing from top to bottom and bottom to top. The concentrated pressure from the crests causes permanent deformation of the interlaced yarn segments at the nodes, twisting them from the intersection of two independent planes of yarn into a three-dimensional twisted structure containing bidirectionally interlaced yarns. The yarn segments from top to bottom are laterally constrained by the lower mesh edge, and the yarn segments from bottom to top are laterally constrained by the upper mesh edge, resulting in permanent plastic bending under the crest pressure, forming a mechanical lock.

[0014] In a second aspect of the invention, an elastic preload roller is provided between the yarn-drawing needle roller assembly and the wavy toothed pressure-locking roller. The elastic preload roller applies a continuous normal pressing force to the double-layered overlapping edges carrying the bidirectional interlocking points, thereby limiting the relative displacement of the double-layered overlapping edges and initially pressing and shaping the bidirectional interlocking points, ensuring that the bidirectional interlocking points maintain positional accuracy as they enter the wavy toothed pressure-locking roller. The elastic preload roller and the wavy toothed pressure-locking roller are arranged adjacent to each other. After the blunt-tipped yarn-drawing needle retracts, the bidirectional interlocking points are only initially positioned by the lateral constraint of the mesh edge, and have not yet formed a permanent connection. Through the pressing constraint of the elastic preload roller, the bidirectional interlocking points enter the wavy toothed pressure-locking roller within a very short time window, completing the plastic pressure-locking before the yarn segment rebounds due to its own tension.

[0015] The key to timing coordination lies in the extremely short time window and the close proximity of the arrangement. After the yarn-pulling needle completes the bidirectional pushing, the yarn segment pushed into the mesh of the opposite layer is in a preliminary interlacing state and has the potential for elastic rebound. The distance between the elastic preload roller and the wavy toothed locking roller is extremely small, and the time from when the double-layer overlapping edge comes out of the elastic preload roller to when it enters the wavy toothed locking roller is extremely short. Before the yarn segment has a significant rebound due to its own tension, it is plastically locked by the wavy toothed locking roller, permanently shaping the yarn segment at the node.

[0016] In a third aspect of the invention, an active clamping roller is provided between the three-dimensional gradient spiral guide groove and the yarn-pulling needle roller assembly to maintain a tight fit between the double-layer overlapping edges.

[0017] The active clamping rollers consist of two opposing rollers that apply a continuous clamping force to the double-layered overlapping edges. The paper flocking dry wire has a high open-pore structure; after folding 180°, the two layers of dry wire are overlapped with misaligned meshes. During the suspended travel section from the guide groove exit to the needle roller pressing zone, tension fluctuations in the overall dry wire may cause slight relative displacement or localized separation between the two layers. The active clamping rollers maintain a tight fit between the two layers of dry wire before they enter the needle roller station by continuously clamping them, providing a stable geometric foundation for subsequent bidirectional pushing through the layers.

[0018] In a fourth aspect, the present invention provides two adjustment schemes for the thickness differences of dry wire mesh of different specifications.

[0019] The first option is a manual spiral adjustment mechanism, used to manually adjust the working parameters of the needle roller, preload roller, and corrugated roller when the machine is stopped. The upper needle roller, elastic preload roller, and corrugated toothed pressure-locking roller of the yarn-drawing needle roller assembly are each equipped with a spiral adjustment mechanism. This mechanism allows for manual adjustment of the pressing depth of the upper needle roller, the spring preload of the elastic preload roller, and the engagement depth of the upper pressure roller when the machine is stopped. After adjustment, the mechanism is fixed by a locking mechanism. The operator consults the equipment adjustment reference table according to the edge thickness of the yarn to be processed, manually adjusts the three spiral mechanisms to the corresponding positions, and locks them.

[0020] The second option is an automatic servo adjustment mechanism for adaptive adjustment during continuous operation. The upper guide roller, elastic preload roller, and upper pressure roller of the wave-toothed pressure-locking roller assembly are each connected to a servo cylinder. The control system automatically adjusts the pressing depth of the upper guide roller, the spring preload of the elastic preload roller, and the engagement depth of the upper pressure roller based on the thickness value of the double-layer overlapping edge detected by a thickness sensor. This automatic adjustment scheme offers fast response and high precision, making it suitable for high-end automated production lines.

[0021] This invention provides an automatic edge-sealing device during the flocking process of a mesh blanket. It has the following beneficial effects: 1. This invention utilizes a bidirectional pushing mechanism with opposing blunt-tipped yarn-pulling needles to push the yarn segments of the upper base mesh into the lower mesh openings, and vice versa, forming a bidirectional interlocking layered structure. The mechanical constraint of the yarns and mesh openings within the base mesh achieves a secure connection, eliminating the need for external media such as glue or sewing. The finishing edge maintains the same permeability as the main body of the dryer, ensuring unaffected air permeability and dehydration performance during operation in the paper machine's drying section. Simultaneously, the edge retains its original flexibility, preventing hardening and cracking, resulting in a service life consistent with the main body of the dryer. Furthermore, the absence of seam protrusions fundamentally eliminates the risk of felt marks.

[0022] 2. This invention sets the trough pitch of the corrugated toothed locking roller to be equal to the needle-punching pitch of the yarn-drawing needle roller, and precisely adjusts the phase angle through a phase coupling. This ensures that each bidirectional interlocking point falls precisely into the trough position as the yarn advances, generating plastic locking under concentrated pressure from the crests on both sides. Simultaneously, the elastic preload roller and the corrugated roller are arranged adjacent to each other, creating an extremely short time window to complete the plastic locking before the yarn segment rebounds due to elastic tension. Phase coupling from a spatial geometric dimension and temporal coordination from a temporal dimension provide dual protection to ensure that each interlocking point forms a permanent connection. Attached Figure Description

[0023] Figure 1 This is a frontal perspective view of the present invention; Figure 2 This is a rear perspective view of the present invention; Figure 3 This is a schematic diagram of the structural distribution of the present invention; Figure 4 This is a three-dimensional schematic diagram of the three-dimensional gradient spiral guide groove in this invention; Figure 5 This is a three-dimensional schematic diagram of the needle roller in this invention; Figure 6 This is a three-dimensional schematic diagram of the pressure roller in this invention.

[0024] Among them, 1. Three-dimensional gradient spiral guide groove; 2. Yarn-pulling needle roller assembly; 201, needle roller; 2011, blunt-tipped yarn-pulling needle; 3. Wave-toothed pressure-locking roller; 301, pressure roller; 4. Active clamping roller; 401, roller; 5. Elastic pre-pressure roller. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The automatic edge-sealing device provided by this invention is suitable for edge-sealing of paper flocking dry nets. The paper flocking dry net uses polyester woven dry net or polyester spiral dry net as its skeleton, and high-temperature resistant short fibers are implanted into the dry net through a needle-punching process to form a fabric with a multi-layered composite structure. The dry net has a high-aperture mesh structure with large and regular mesh openings, typically 5-15mm in size, and an opening rate of 40%-70%. The dry net is made of polyester yarn woven or spirally wound, with yarn diameters typically 0.5-2mm, possessing high tensile strength and elastic modulus. Depending on the flocking process, flocking dry nets are divided into single-sided flocking dry nets and double-sided flocking dry nets. The typical thickness range for single-sided flocking dry nets is 1.5-3mm, and the typical thickness range for double-sided flocking dry nets is 3-6mm.

[0027] To facilitate the description of the device's spatial structure, a right-handed coordinate system is established: the X direction represents the direction of the main fabric's movement, the Y direction is the horizontal direction, and the Z direction is the vertical direction. The device acts on one side edge of the main fabric, which is located at the positive end in the Y direction. The main body of the device, acting on the positive edge of the main fabric in the Y direction, is a frame composed of two vertical side plates, with the rollers horizontally mounted along the Y direction. The main fabric enters horizontally, advances along the X direction, and its edge is located on the positive Y side.

[0028] The dimensional parameters, material selections, and process parameters involved in the following embodiments are all exemplary values ​​and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can reasonably adjust and optimize these parameters according to actual application scenarios without departing from the core technical solution of this invention, and all such adjustments and optimizations fall within the scope of protection.

[0029] In this invention, a mesh node refers to the node location where yarns intersect, overlap, or weave in the dry net mesh structure. For polyester woven dry nets, the mesh node is the intersection point of warp and weft yarns; for polyester spiral dry nets, the mesh node is the overlap point of adjacent spiral yarns. The yarn segment at the mesh node refers to the small segment of yarn located at the node position that can be pushed by the tip of the yarn-pulling needle, typically 2-8 mm in length.

[0030] In this invention, the bidirectional interlocking point refers to the interlocking structure formed at a node position on the edge of the double-layer overlap after being pushed through the layers by the upper and lower guide rollers 201. This interlocking point simultaneously includes an upper yarn segment pushed from the upper dry web into the mesh of the lower dry web, and a lower yarn segment pushed from the lower dry web into the mesh of the upper dry web. The two yarn segments interweave at the node and are laterally constrained by the mesh edges of the opposite layer, forming a three-dimensional mechanical connection.

[0031] In this invention, plastic pressure locking refers to applying concentrated mechanical pressure to the bidirectional interlocking point through a wave-toothed pressure locking roller 3, causing the polyester yarn at the interlocking point to undergo permanent plastic deformation exceeding the elastic limit, so that the yarn segment remains in the twisted state after pressure locking after the pressure is released, and no elastic recovery occurs.

[0032] In this invention, the timing coordination refers to the process whereby after the yarn-pulling needle roller assembly 2 completes the bidirectional pushing to form an interlocking point, the elastic pre-pressure roller 5 and the wave-toothed locking roller 3 sequentially apply pre-pressure and locking to the interlocking point within a very short time window, ensuring that permanent plastic locking is completed before the yarn segment at the interlocking point experiences significant rebound due to its own elastic tension.

[0033] In this invention, phase coupling refers to setting the trough pitch of the wave toothed pressure lock roller 3 to be equal to the needle insertion pitch of the needle roller 201, and precisely adjusting the phase angle between the two through a phase coupling, so that the X-direction coordinate position of each bidirectional interlocking point formed by the yarn drawing needle roller assembly 2 corresponds exactly to the trough position of the wave roller during the advance of the dry web, thereby ensuring that each interlocking point falls into the trough and is subjected to concentrated pressure from the wave peaks on both sides.

[0034] Please see the appendix Figure 1 - Appendix Figure 6This invention provides an automatic edge closing device for the flocking process of papermaking wire mesh, which is used for edge closing of the flocking wire mesh. It includes a three-dimensional gradient spiral guide groove 1, an active clamping roller 4, a yarn-pulling needle roller assembly 2, an elastic pre-pressure roller 5, and a wave-tooth pressure-locking roller 3 arranged sequentially along the wire mesh traveling direction.

[0035] The frame of the device consists of two vertical side plates, which are parallel to each other along the Y-direction and connected by a cross brace to form a rigid frame. Each roller is horizontally mounted along the Y-direction, with its ends fixed by bearing seats on the side plates. The upper roller, which requires vertical adjustment, has its bearing seat installed in a vertical groove on the side plate and is raised or lowered by a screw adjustment mechanism or a servo cylinder.

[0036] The paper flocking wire enters horizontally from the feed end, with the main body of the wire moving horizontally forward, except for the positive edge of the Y-axis which enters the processing area of ​​the device. The wire travels continuously in the positive X-axis direction, with the rotational speed of each roller synchronized with the travel speed to ensure no relative slippage.

[0037] The side edge of the dry net first enters the three-dimensional gradient spiral guide groove 1. The cross-section of the guide groove is three-segmented gradient along the X direction: the inlet segment is a horizontal straight plate that supports the flat edge; the middle segment is an L-shaped guide that folds the edge by about 90°; and the outlet segment is a C-shaped section that folds the edge to 180°. After folding, the flocked fiber layer faces outward, and the two layers of dry net mesh are placed side by side to form a double-layered overlapping edge. The double-layered overlapping edge is a flat strip and is horizontally placed on the upper surface of the dry net body near the Y-side.

[0038] The folded double-layered overlapping edges enter the clamping area of ​​the active clamping roller 4. The active clamping roller 4 includes two rollers 401 positioned vertically opposite each other, which apply a continuous clamping force to the double-layered overlapping edges through elastic loading. The main mesh has a high porosity structure, and after folding, the two layers of main mesh are overlapped with misaligned mesh openings. During the suspended stroke, the tension fluctuation of the main mesh causes slight relative displacement between the two layers. The active clamping roller 4 maintains a tight fit through continuous clamping, providing a stable geometric prerequisite for subsequent bidirectional jacking.

[0039] The double-layered overlapping edges enter the pressing zone of the yarn-drawing needle roller assembly 2 in a tightly fitted state. The yarn-drawing needle roller assembly 2 includes two needle rollers 201 positioned vertically opposite each other, with blunt-tipped yarn-drawing needles 2011 radially distributed along the rim of the needle rollers 201. The blunt-tipped yarn-drawing needles 2011 of the upper needle roller 201 penetrate the double-layered overlapping edge from top to bottom, and the needle tips push the yarn segments at the mesh nodes of the upper dry web downwards, causing them to pass through the two-layer contact interface and enter the lower mesh. The blunt-tipped yarn-drawing needles 2011 of the lower needle roller 201 penetrate the double-layered overlapping edge from bottom to top, and the needle tips push the yarn segments at the mesh nodes of the lower dry web upwards, causing them to pass through the contact interface and enter the upper mesh.

[0040] The blunt-tipped yarn-drawing needle 2011 has a rigid metal body with a smooth, barbless surface. When the needle retracts, due to its smooth surface and lack of barbs, it does not engage with the yarn segment. The upper yarn segment remains within the lower mesh opening, with the lower mesh opening edge acting as a lateral constraint, and the lower yarn segment remains within the upper mesh opening, with the upper mesh opening edge acting as a lateral constraint, forming a bidirectional interlocking point. The upper and lower needle rollers 201 rotate synchronously, with the needle-punching action alternating densely, forming a continuously distributed band of bidirectional interlocking points along the direction of the dry web's travel.

[0041] After the double-layered overlapping edge carrying the bidirectional interlocking points leaves the pressing area of ​​the needle roller 201, it immediately enters the pressing area of ​​the elastic preload roller 5. The elastic preload roller 5 applies a continuous normal pressing force to the double-layered overlapping edge, restricting relative displacement and initially pressing and shaping the bidirectional interlocking points to maintain their positional accuracy. At this time, the bidirectional interlocking points are in a preliminary interlacing state, and the yarn segments have not yet formed a permanent bond, exhibiting a tendency for elastic rebound. The elastic preload roller 5 stabilizes the geometric position of the interlocking points through pressing constraints, suppressing the initial rebound of the yarn segments.

[0042] After the double-layered overlapping edges are pressed together by the elastic preload roller 5, they enter the meshing area of ​​the corrugated toothed locking roller 3 within a very short distance. The elastic preload roller 5 and the corrugated toothed locking roller 3 are arranged adjacent to each other, and the bidirectional interlocking point enters the corrugated toothed locking roller 3 before it has a significant rebound due to its own tension within a very short time window.

[0043] The corrugated toothed pressure-locking roller 3 includes two pressure rollers 301 positioned vertically opposite each other with complementary corrugated tooth patterns on their surfaces. The trough pitch of the pressure roller 301 is equal to the needle-punching pitch of the needle roller 201. The pressure roller 301 and the needle roller 201 are connected by a synchronous transmission mechanism containing a phase coupling. The phase angle is adjusted while maintaining a constant transmission ratio, so that each bidirectional interlocking point falls precisely into the trough position as the main web advances.

[0044] When the two pressure rollers 301 mesh, the bidirectional interlocking point located at the trough is subjected to concentrated pressure from both crests. The bidirectional interlocking point simultaneously involves yarn segments interlacing from top to bottom and bottom to top. The concentrated pressure from the crests causes permanent deformation of the interlaced yarn segments at the nodes, twisting them from the intersection of two independent planar yarns into a three-dimensional knotted structure containing bidirectionally interlaced yarns. The yarn segments from top to bottom are laterally constrained by the lower mesh edge, and the yarn segments from bottom to top are laterally constrained by the upper mesh edge, resulting in permanent plastic bending under crest pressure, forming a mechanical lock.

[0045] After the double-layer overlap edge is pressed and locked, it leaves the corrugated roller exit, and the edge finishing is completed. The double-layer overlap edge forms a continuous bidirectional interlocking bond along the direction of the dry web travel. The upper and lower dry webs are firmly bonded together without external medium through bidirectional interlocking of yarns and plastic pressing and locking.

[0046] The entire finishing process is completed during the continuous movement of the dry web, with each functional module connected in space and coordinated in time. The three-dimensional gradient spiral guide groove 1 completes a 180° fold to form a double-layer overlapping edge; the active clamping roller 4 maintains the double-layer adhesion to provide a stable premise for bidirectional pushing; the yarn-pulling needle roller assembly 2 completes the bidirectional interlocking of the upper and lower yarns to form a preliminary interlock; the elastic pre-pressure roller 5 applies pre-pressure to the interlocking points to stabilize the position; the wave-tooth pressure-locking roller 3 accurately positions and applies plastic pressure-locking through phase coupling to complete permanent bonding.

[0047] Unlike traditional needle punching methods that rely on barbed hooks to engage fibers, this device uses blunt-tipped, barbless needles (2011) to push yarn segments from one layer of dry web into the mesh of the opposite layer through a pushing mechanism rather than a hooking mechanism. The upper needle roller pushes the upper layer yarn into the lower layer, and the lower needle roller pushes the lower layer yarn into the upper layer, forming a two-way interlocking structure. Because the blunt-tipped needle has a smooth surface, the yarn segment is not pulled back by the needle when it withdraws, naturally remaining within the mesh of the opposite layer, fundamentally eliminating the material slippage problem of traditional barbed needles.

[0048] The phase coupling mechanism of the wave-toothed pressure-locking roller 3 is key to achieving precise pressure locking. By ensuring that the trough pitch is equal to the needle-punching pitch and by precisely adjusting the phase angle through a phase coupling, each bidirectional interlocking point falls precisely into the trough. The wave crests on both sides apply concentrated pressure to the interlocking points, causing permanent plastic deformation of the interlaced yarn segments at the nodes, forming a three-dimensional twisted structure. Phase coupling ensures the effectiveness of pressure locking from a spatial geometric dimension.

[0049] The close proximity arrangement of the elastic preload roller 5 and the corrugated toothed locking roller 3 constitutes a time-sequential coordination mechanism. The time window from the formation of the bidirectional interlocking point to the locking is extremely short, and permanent locking is completed before the yarn segment rebounds due to its own tension. Time-sequential coordination ensures the reliability of the connection from a time perspective.

[0050] The diameter of the needle roller 201 and the length of the blunt-tipped yarn-pulling needle 2011 are matched with the working window angle, ensuring that the lateral displacement of the needle tip's arc trajectory relative to the paper web is less than the size of a single mesh opening. The blunt-tipped yarn-pulling needle 2011 completes the penetration and pushing action within the same mesh opening, with lateral sliding accommodated by the mesh gaps, without crossing the yarn or tearing the mesh. Utilizing the large mesh opening characteristics of the papermaking paper web, rotary piercing becomes feasible in this application scenario.

[0051] In this embodiment, the three-dimensional gradient spiral guide groove 1 is used to fold the side edge of the dry net from a flat state to 180°, and the active clamping roller 4 is used to maintain the tight fit of the double-layer overlapping edges after folding.

[0052] The three-dimensional gradient spiral guide groove 1 is a bent metal component extending along the X direction, acting only on the edge strip of the main mesh. The cross-section of the groove changes in three segments along the X direction, guiding the edge of the main mesh from flat to vertical and finally folding to 180° through continuous changes in cross-sectional shape.

[0053] The inlet section has a horizontal, straight plate shape with the same width as the edge of the dry net. The plate surface is parallel to the XY plane, fully open with the plate surface facing upwards, and its width is equal to the width of the edge to be closed. The side edge of the dry net enters horizontally and lies smoothly on the straight plate surface.

[0054] The middle section transitions from a flat plate shape to an L-shape. The bottom edge remains horizontal, supporting the bottom surface of the edge, while the vertical edge rises upward along the Z-direction, closely adhering to the side of the edge. The height of the vertical edge gradually increases along the X-direction, until at the end of the middle section, the height of the vertical edge is equal to the width of the edge, and the edge is guided to fold from a flat position to an approximately 90° vertical position.

[0055] The cross-section of the exit section continues to curl from an L-shape to a C-shape. The bottom arc of the C-shape supports the bottom surface of the edge, the vertical section extends to the side, and the top arc continues to bend inward from the side, passing over the main body of the trunk net, gradually completing the folding of the edge from 90° to 180° within this section.

[0056] After folding, the flocked fiber layer faces outwards, and the two dry mesh layers are placed face-to-face. The fiber surface originally facing the +Z direction remains facing the +Z direction after folding, while the fiber surface originally facing the -Z direction faces the -Z direction after folding 180°. The two fiber surfaces are located on the upper and lower outer surfaces of the double-layer overlap, respectively. After folding, the mesh surfaces of the two dry mesh layers become face-to-face, forming a contact interface.

[0057] The C-shaped cross-section keeps the open side open to allow the main body of the dry net to pass through. The C-shaped arc encloses the folded edge strips, applying a slight constraint to the edges to prevent them from unfolding after folding. The contact pressure is small and only serves to shape the strips.

[0058] The guide groove is fixed to the inner side of the frame near the side plate by an L-shaped or T-shaped bracket. The guide groove is a stationary part and does not participate in rotation or movement. It relies entirely on the fixed geometry to guide the edge to complete the folding.

[0059] The active clamping roller 4 is positioned between the guide groove outlet and the yarn-feeding needle roller assembly 2 inlet, and includes two rollers 401 positioned vertically opposite each other. The axes of the two rollers 401 are arranged horizontally along the Y direction, facing each other vertically, and the double-layered overlapping edge passes horizontally through the gap between the two rollers 401. The bearing seat of the lower roller 401 is fixedly mounted on the side plate of the frame, and the bearing seat of the upper roller 401 is mounted in a vertical slide groove in the side plate, allowing it to slide along the Z direction.

[0060] A push rod is connected above the bearing housing of the upper roller 401. The push rod extends upward through the side plate, and a compression spring is fitted on the upper end of the push rod. The upper end of the compression spring abuts against the fixed support on the outer side of the side plate, and the lower end presses against the retaining ring at the top of the push rod. The compression spring applies an elastic force downward, and the push rod transmits this elastic force to the bearing housing of the upper roller 401. The upper roller 401 is pressed downward against the lower roller 401, applying a clamping force to the double-layered overlapping edge passing through the roller gap.

[0061] The upper and lower rollers 401 rotate synchronously in opposite directions via gear meshing. A driving gear is mounted at one end of the lower roller 401's shaft, and a driven gear is mounted at the corresponding position on the upper roller 401's shaft. The two gears mesh on the outer side of the side plate. This gear transmission ensures that the upper and lower rollers rotate in opposite directions, so that at the roller gap, the surfaces of both rollers 401 move in the positive X direction, consistent with the direction of the main web's movement. A synchronous pulley is mounted at the other end of the lower roller 401's shaft, connecting to the main drive system via a synchronous belt. This ensures that the linear velocity of the lower roller 401's surface is strictly synchronized with the main web's movement speed, preventing pulling or material accumulation at the double-layered overlapping edges within the roller gap.

[0062] The gap width of the upper and lower rollers 401 is set according to the thickness of the double-layered edge. The gap width is slightly smaller than the natural thickness of the edge, so that the edge is subjected to appropriate normal compression when passing through the gap. The appropriate amount of compression ensures sufficient clamping force without excessively flattening the dry web.

[0063] As the active clamping roller 4 passes through the edge of the double-layered overlap, the upper and lower rollers 401 apply a continuous normal clamping force and a tangential traction force to the edge. The normal clamping force is provided by an elastic loading mechanism, and the tangential traction force is provided by the active rotation of the roller 401 and the friction force of the rubber surface. The normal clamping force presses the two layers of dry netting to inhibit relative slippage, and the tangential traction force drives the edge of the double-layered overlap to advance in the X direction in sync with the dry netting.

[0064] The dry web has a high-aperture mesh structure. After folding, the two layers of dry web are overlapped with staggered mesh openings, and the flocked fiber layer is sparse, with no bonding or stitching between the two layers. In the suspended travel section from the guide groove outlet to the inlet of the yarn-pulling needle roller assembly 2, without external force constraint, the tension fluctuation of the dry web can cause slight relative displacement or local separation of the two layers. The active clamping roller 4 eliminates this potential problem by continuously clamping, maintaining a tight fit between the two layers of dry web, and providing a stable geometric premise for subsequent bidirectional pushing through the layers.

[0065] In this embodiment, the yarn-pulling needle roller assembly 2 is the core mechanism for the device to achieve bidirectional interlocking and layer-penetrating connection without external medium. It includes two needle rollers 201 that are positioned vertically opposite each other and blunt-tipped yarn-pulling needles 2011 that are radially distributed along the rim of the needle rollers.

[0066] Two needle rollers 201 are arranged vertically opposite each other, with their rotation axes both horizontally set along the Y direction and parallel to each other. The bearing seat of the lower needle roller 201 is fixedly mounted on the side plate of the frame, while the bearing seat of the upper needle roller 201 is installed in a vertical groove on the side plate and can slide up and down. The double-layer overlapping edge passes horizontally through the gap between the two needle rollers 201 and advances along the X direction.

[0067] The needle roller 201 has a cylindrical body with a large diameter. This large diameter design is based on kinematic constraints, meaning that the larger the diameter of the needle roller 201, the closer the arc trajectory of the needle tip is to a straight line near the roller gap point, and the smaller the lateral displacement of the needle tip relative to the dry web.

[0068] The needle roller 201 has its two ends passing through bearing seats on the side plates and supported by deep groove ball bearings or tapered roller bearings. One end of the roller is equipped with a synchronous pulley for transmission connection, and the other end is equipped with a synchronous pulley or gear for phase coupling synchronous transmission with the wave roller.

[0069] The blunt-tip yarn-drawing needle 2011 has a cylindrical straight rod or a slightly tapered rod. The needle length is set according to the short needle principle. The shorter the needle body, the smaller the difference between the radius of the needle tip and the pitch circle radius of the roller, the smaller the difference between the linear velocity of the needle tip and the forward speed of the dry web at the roller gap point, and the smaller the lateral slippage. The blunt-tip yarn-drawing needle 2011 has two needle tip design forms: blunt-tip needle tip or forked-tip yarn-drawing needle tip.

[0070] The gap adjustment mechanism of the needle roller 201 is used to adjust the gap width between the upper and lower needle rollers 201, that is, to adjust the pressing depth of the blunt-tipped yarn-drawing needle 2011. A screw adjustment mechanism or servo cylinder is connected above the bearing seat of the upper needle roller 201 to drive the bearing seat to move up and down within the groove. The screw adjustment mechanism includes a vertically arranged adjusting screw, nut, handwheel, and locking nut. The operator rotates the handwheel to drive the screw to rotate, and the nut moves up and down along the screw, causing the upper needle roller 201 to move up and down. In the servo cylinder mode, the servo cylinder body is fixed on the bracket above the side plate, and the piston rod is vertically connected downwards to the bearing seat of the upper needle roller 201. The extension and retraction of the piston rod is controlled by adjusting the air pressure of the servo cylinder through the control system.

[0071] The gap width of the upper and lower needle rollers 201 is set according to the thickness of the double-layer overlapping edge. The gap width is slightly smaller than the edge thickness, so that the edge is subjected to appropriate normal clamping force when passing through the gap, and the two layers of dry web are tightly bonded without relative slippage. The blunt-tipped yarn-drawing needle 2011 is the depth to which the needle tip penetrates from one side surface, penetrates both layers, and protrudes from the other side surface when the needle tip penetrates the double-layer overlapping edge. The depth setting ensures that the needle tip can penetrate the double-layer dry web and enter the mesh node area of ​​the opposite layer dry web to press against the yarn segment at the mesh node.

[0072] The needle roller 201 is driven by a synchronous transmission mechanism. The main drive motor outputs power through a reducer, which is then transmitted to the roller shaft of the lower needle roller 201 via a synchronous belt or chain. One end of the roller shaft of the lower needle roller 201 is equipped with a driving synchronous pulley, and the corresponding position on the roller shaft of the upper needle roller 201 is equipped with a driven synchronous pulley. The two synchronous pulleys are connected by a synchronous belt. The synchronous belt drive ensures that the speed ratio of the upper and lower needle rollers 201 is constant at 1:1, with opposite directions of rotation. At the roller gap, the roller surfaces of both needle rollers 201 move in the positive X direction. The speed setting of the needle roller 201 ensures that the linear velocity of the roller surface is strictly synchronized with the traveling speed of the dry web.

[0073] The double-layered overlapping edges are kept in close contact under the clamping action of the active clamping roller 4 and enter the pressure zone of the needle roller 201. The upper and lower dry mesh surfaces are relatively close to each other, and the mesh holes of the two dry meshes are staggered and overlapped. The positions of the upper mesh holes and the lower mesh holes do not completely coincide on the plane projection.

[0074] As the upper guide roller 201 rotates, the blunt-tipped yarn-drawing needle 2011, located within the working window angle near the roller gap point, approaches the double-layer overlapping edge from top to bottom. The needle tip first contacts the upper dry web surface. Due to the large mesh openings of the upper dry web, the needle tip easily finds the mesh opening position and enters. The needle body passes through the mesh openings of the upper dry web radially, and the needle tip enters the contact interface area between the upper and lower dry webs. The needle tip continues to move downwards to contact the mesh nodes of the upper dry web. For polyester woven dry webs, the mesh nodes are the intersection points of warp and weft yarns; for polyester spiral dry webs, the mesh nodes are the overlap points of adjacent spiral yarns. The blunt tip or forked notch of the needle tip contacts and abuts the yarn segment at the mesh node.

[0075] The needle roller 201 continues to rotate, with the needle tip having a downward radial component relative to the direction of movement of the dry web. The needle tip applies a downward pushing force to the yarn segment, causing it to displace downward from the upper dry web plane under this force. Both ends of the yarn segment remain connected to other positions on the upper dry web. The yarn segment itself is elastic and flexible, and under external force, it undergoes bending deformation. The needle tip continues to push, causing the yarn segment to bend downward and pass through the contact interface between the upper and lower dry web layers, entering the mesh opening area of ​​the lower dry web. The mesh openings of the lower and upper dry web layers are staggered, with the position where the upper yarn segment is pushed corresponding to a mesh opening in the lower dry web. After passing through the contact interface from the upper plane, the yarn segment enters the lower mesh space, using the edge of the lower mesh opening as a support point.

[0076] After the needle tip pushes the yarn segment into the lower mesh, the needle roller 201 continues to rotate. The needle passes the roller gap point, and its direction of movement relative to the dry web changes to be away from the lower dry web. The needle begins to withdraw from the double-layer overlapping edge. Because the blunt-tipped yarn-pulling needle 2011 has a completely smooth surface without barbs, there is no engagement or hooking between the needle and the yarn segment during withdrawal, and the yarn segment is not pulled back by the needle. At this point, the yarn segment has been pushed into the lower mesh, crossing the contact interface between the two dry web layers. One end remains at the node of the upper dry web, while the other end or the middle section is located in the lower mesh, with the lower mesh edge acting as a lateral support constraint. The lower mesh edge forms a geometric constraint on the yarn segment, preventing it from retracting back to its original position in the upper layer. After the needle is completely withdrawn, the upper yarn segment remains in the lower mesh, forming a top-down cross-layer interweaving.

[0077] The working principle of the lower guide roller 201 is completely symmetrical to that of the upper guide roller 201. When the lower guide roller 201 rotates, the blunt-tipped yarn-drawing needle 2011, located within the working window angle near the roller gap point, approaches the double-layer overlapping edge from bottom to top. The needle tip contacts the lower surface of the lower dry web, passes through the mesh opening of the lower dry web, and enters the contact interface area between the lower and upper dry webs. The needle tip contacts and presses against the yarn segment at the mesh node of the lower dry web. As the needle roller continues to rotate, the needle tip has an upward radial component relative to the direction of movement of the dry web, applying an upward pushing force to the yarn segment. Under the action of this pushing force, the yarn segment displaces upward from the plane of the lower dry web, bends upward, crosses the contact interface, and enters the mesh opening area of ​​the upper dry web. After entering the upper mesh, the yarn segment uses the edge of the upper mesh as a support point. As the needle roller continues to rotate, the needle passes the gap point and begins to withdraw. The needle surface is smooth and without barbs. When the needle withdraws, the yarn segment is not pulled back by the needle. The lower layer yarn segment remains in the upper layer mesh, forming a cross-layer interweaving from bottom to top.

[0078] At any cross-sectional position along the X direction, after dense and alternating punctures by upper and lower needles, yarn segments simultaneously interweave from top to bottom and from bottom to top. The upper layer yarn segment is pushed into the lower layer mesh, with the lower layer mesh edge as the lateral constraint, and the lower layer yarn segment is pushed into the upper layer mesh, with the upper layer mesh edge as the lateral constraint. The two yarn segments intersect at the node, forming a bidirectional interlocking point.

[0079] The geometric characteristics of a bidirectional interlocking point are that a portion of the upper yarn segment is located within the lower mesh opening, and a portion of the lower yarn segment is located within the upper mesh opening, with the two yarn segments intersecting three-dimensionally at the node. The upper yarn segment is laterally held in place by the edges of the lower mesh openings, and the lower yarn segment is laterally held in place by the edges of the upper mesh openings. Each yarn segment provides a locking mechanism to the other layer and is also constrained by the edges of the other layer's mesh openings, forming a bidirectional interlock. At this stage, the bidirectional interlocking point is in a preliminary interlocking state and has not yet formed a permanent bond; the yarn segments still exhibit elasticity and a tendency to rebound. Subsequent pre-compression and plastic compression are required to eliminate the elastic rebound tendency of the yarn segments and form a permanent bond.

[0080] In this embodiment, the blunt-tipped yarn-drawing needle 2011 is fixed on the rotating needle roller 201. The needle tip follows the rotation of the needle roller 201 along an arc trajectory, while the double-layered overlapping edge moves in a straight line along the X direction. The two are only tangent at the roller gap point. The kinematic constraints of the rotational puncture ensure that the lateral displacement of the needle tip during the puncture process is less than the size of a single mesh opening in the dry web, allowing the needle to complete the penetration and pushing action within the same mesh opening.

[0081] The roll gap point is defined as the closest position between the upper and lower needle rollers 201. This point is located at the midpoint of the line connecting the centers of the two needle rollers 201, corresponding to the position where the double-layer overlapping edge passes horizontally. At the roll gap point, the tangential direction of the needle roller 201 surface is parallel to the traveling direction of the double-layer overlapping edge, and the linear velocity of the needle roller 201 surface is equal to the traveling speed of the dry web.

[0082] The working window angle is defined as the circumferential angle range within which the blunt-tipped yarn-drawing needle 2011 on the needle roller 201 actually contacts the double-layered overlapping edge. The working window angle extends a certain angle to both sides of the roller gap point. The blunt-tipped yarn-drawing needle 2011 only contacts the double-layered overlapping edge when it enters the working window angle range; outside the range, the needle tip separates from the double-layered overlapping edge. The size of the working window angle is determined based on the needle roller diameter, needle body length, and the thickness of the double-layered overlapping edge.

[0083] The circular trajectory of the needle tip within the working window angle range causes a lateral displacement relative to the yarn bed. Lateral displacement refers to the component of displacement of the needle tip in a direction perpendicular to the yarn bed's travel direction. Because the needle roller 201 rotates in a circular motion, the needle tip travels in an arc, while the yarn bed moves in a straight line; this difference in trajectory results in lateral slippage. The magnitude of the lateral displacement is related to the diameter of the needle roller 201, the size of the working window angle, and the length of the blunt-tipped yarn-drawing needle 2011.

[0084] The larger the diameter of the needle roller 201, the closer the needle tip arc is to a straight line near the roller gap point, and the smaller the lateral displacement. The smaller the working window angle, the shorter the arc length traversed by the needle tip, and the smaller the lateral displacement. The shorter the needle body length, the smaller the difference between the radius of the needle tip and the pitch circle radius of the roller body, the smaller the difference between the linear velocity of the needle tip and the forward speed of the dry web, and the smaller the lateral displacement.

[0085] In this embodiment, the diameter of the needle roller 201 is set to 200-400mm, which is a large diameter design. Taking a roller diameter of 300mm as an example, the lateral displacement of the needle tip in the Y direction within the working window angle of ±20° is approximately 6-8mm. This lateral displacement is caused by the geometric deviation between the circular trajectory and the straight trajectory. The specific value is calculated through geometric relationships: when the needle tip rotates from a -20° position to a +20° position on the circumference, the change in the Y coordinate of the needle tip is the lateral displacement.

[0086] The blunt-tip yarn-drawing needle 2011 has a needle length set at 15-25mm, which is a short needle design. The short needle design minimizes the difference between the radius of the needle tip and the pitch circle radius of the roller. Taking a roller diameter of 300mm and a needle length of 20mm as an example, the radius of the needle tip is 150mm + 20mm = 170mm, while the roller surface radius is 150mm, resulting in a 20mm difference in radius. At the same angular velocity, this 20mm radius difference leads to a linear velocity difference of approximately 13%, which translates into lateral slippage velocity. The short needle design minimizes this radius difference, suppressing lateral slippage.

[0087] The individual mesh size of paper flocking drywall is typically 5-15 mm. The mesh size of polyester woven drywall is determined by the weaving density; the larger the warp and weft yarn spacing, the larger the mesh size. The mesh size of polyester spiral drywall is determined by the spiral yarn pitch and overlap method. For drywall with an open area ratio of 40%-70%, the individual mesh size is typically in the range of 5-15 mm.

[0088] In this embodiment, the lateral displacement of the blunt-tipped yarn-drawing needle 2011 is controlled within 6-8mm by the coordinated matching of the large roller diameter, short needle, and narrow working window angle, which is less than the upper limit of 15mm for a single mesh size in the dry yarn. This constraint ensures that the needle tip moves within the same mesh size throughout the entire process from insertion to withdrawal.

[0089] When the needle tip enters the dry web, it passes through a mesh opening, contacts and pushes against the yarn segment at that mesh node, and exits through the same mesh opening. Throughout the process, the lateral displacement of the needle tip is accommodated by the mesh gap, and the needle tip does not cross into adjacent meshes or contact the yarn in adjacent meshes.

[0090] In this embodiment, the constraint that the lateral displacement is less than the mesh size is the fundamental reason why rotary puncture is feasible in the application scenario of paper flocking dry wire. Traditional needle punching equipment usually uses a reciprocating linear motion needle plate, and the needle performs linear puncture without lateral slippage. This invention uses a rotating needle roller 201, and the needle performs arc puncture, which involves lateral slippage. However, through kinematic constraints, the amount of lateral slippage is controlled within the mesh size. The large mesh size accommodates the lateral slippage, making rotary puncture feasible.

[0091] When the needle tip moves within the same mesh opening, the yarn segment pushed by the needle tip is located at the mesh opening node. The mesh opening node is located at the yarn intersection around the mesh opening; its position is relatively stable and less affected by lateral slippage. Even if the needle tip slips 6-8mm laterally within the mesh opening, it remains within the mesh gap and can still contact and hold the node yarn segment. The mesh gap provides geometric redundancy for lateral slippage, ensuring that the needle tip can still effectively push after slippage.

[0092] The synchronization between the rotational speed of needle roller 201 and the traveling speed of the yarn is another key element of kinematic constraints. The linear velocity of the needle roller 201 surface is strictly synchronized with the traveling speed of the yarn. The higher the synchronization accuracy, the smaller the slippage of the needle tip along the X direction, the smaller the relative motion between the needle tip and the target yarn segment being pushed, and the higher the pushing accuracy.

[0093] In this embodiment, the large roller diameter, short needles, and narrow working window angle constitute an interrelated set of constraints. These three factors work together to control the lateral displacement within the mesh size. If only a large roller diameter is used while the needle length is long, the increased needle tip radius leads to a greater difference in linear velocity and lateral slippage, failing to meet the constraints. If only short needles are used while the roller diameter is small, the large curvature of the needle tip arc significantly deviates from a straight line, resulting in a greater lateral displacement, also failing to meet the constraints. If the working window angle is too large, the increased circumferential angle of the needle tip within the material and the increased arc length result in a cumulative increase in lateral displacement, also exceeding the constraint range. The coordinated matching of these three factors is determined through geometric analysis and calculation, completed during the equipment design phase, ensuring that the kinematic constraints are met in actual operation.

[0094] In this embodiment, the elastic preload roller 5 is disposed between the yarn-drawing needle roller assembly 2 and the wavy toothed pressure-locking roller 3, applying a continuous normal pressing force to the double-layered overlapping edge carrying the bidirectional interlocking points. The wavy toothed pressure-locking roller 3 applies plastic pressure-locking to the bidirectional interlocking points, causing the yarn segments at the interlocking points to undergo permanent plastic deformation to form a three-dimensional twisted structure.

[0095] The elastic preload roller 5 has its shaft arranged horizontally along the Y direction, with both ends supported by bearing seats. A fixed lower support roller or flat support plate is located below, forming a counter-pressure structure with the elastic preload roller 5. The bearing seats of the elastic preload roller 5 are installed in vertical grooves on the side plate of the frame, and can slide up and down along the Z direction via guide sliders embedded in the grooves. A loading mechanism is connected above the bearing seats, applying downward pressure, which is transmitted to the elastic preload roller 5 through the bearing seats. The elastic preload roller 5 presses down onto the double-layered overlapping edge. The loading mechanism uses either a compression spring or a servo cylinder for loading.

[0096] The elastic preload roller 5 applies a continuous normal pressure to the double-layer overlapping edge, pressing downwards perpendicular to the upper surface of the edge. This pressure is applied continuously and without fluctuation as the double-layer overlapping edge passes beneath the elastic preload roller 5. The continuous pressure, through frictional constraint, limits the relative displacement of the double-layer overlapping edge within this stroke, while simultaneously applying initial pressure and shaping to the bidirectional interlocking points. At the bidirectional interlocking points, the yarn segments are pushed into the mesh openings of the opposite layer after being pushed by the blunt-tipped yarn guide needle 2011. Their position is maintained by the geometric constraints of the mesh opening edges, but the yarn segments undergo bending deformation during the pushing process, accumulating elastic potential energy, and thus exhibiting a tendency to spring back. The elastic preload roller 5 applies normal pressure to the bidirectional interlocking points. This pressure acts at the yarn crossing points, compressing the crossing yarn segments and partially releasing the elastic potential energy at the bending deformation points. The yarn segments undergo initial plastic deformation under pressure, suppressing elastic rebound and improving the stability of the interlocking points.

[0097] The close proximity of the elastic preload roller 5 and the corrugated toothed locking roller 3 is a key element of the timing coordination mechanism. The distance between them in the X direction is extremely small, typically 50-150 mm. Corresponding to a dry web travel speed of 10-50 m / min, the passage time from the exit of the elastic preload roller 5 to the entrance of the corrugated toothed locking roller 3 at the double-layer overlapping edge is 0.06-0.9 seconds. This extremely short time window ensures that the bidirectional interlocking point immediately enters the locking zone of the corrugated toothed locking roller 3 after the initial pressing and shaping by the elastic preload roller 5, and is permanently fixed by the corrugated toothed locking roller 3 through plastic locking before the yarn segment rebounds due to its own tension.

[0098] The wavy toothed pressure-locking roller 3 includes two pressure rollers 301 positioned vertically opposite each other. The axes of both pressure rollers 301 are horizontally arranged along the Y-direction, facing each other directly. The double-layered overlapping edge passes through the wavy gap between the two pressure rollers 301 and advances along the X-direction. The roller surface of the pressure roller 301 is not a smooth cylindrical surface, but rather machined with a wavy toothed profile that undulates along the circumference. The wavy toothed profile is distributed along the circumference of the roller body, forming a periodic alternating structure of peaks and troughs. Peaks are the raised portions of the roller surface, and troughs are the recessed portions, with a smooth curve transitioning between peaks and troughs. The wavy toothed profile curve uses a sine curve or a cosine curve.

[0099] The trough pitch is defined as the arc length between the lowest points of two adjacent troughs after the roller body is unfolded along its circumference. The trough pitch is a key parameter for establishing the phase coupling relationship between the corrugated toothed press-lock roller 3 and the yarn-drawing needle roller assembly 2; the trough pitch is equal to the needle-punching pitch. The needle-punching pitch is defined as the distance between two adjacent bidirectional interlocking points formed by the blunt-tipped yarn-drawing needles 2011 in the direction of the yarn's travel, determined by the number of circumferential rows of the needle roller 201, the roller diameter, and the rotational speed. The needle-punching pitch is calculated by dividing the circumference of the needle roller 201 by the number of circumferential rows, and then multiplying by the synchronization coefficient between the rotational speed of the needle roller 201 and the yarn's travel speed. Taking a roller diameter of 300mm and 36 circumferential rows as an example, the circumference of the needle roller 201 is 942mm, and the needle-punching pitch is 942mm / 36 = 26.2mm. The trough pitch of the corrugated toothed press-lock roller 3 is set to 26.2mm to ensure equal pitch.

[0100] Equal pitch of wave troughs is the geometric prerequisite for phase coupling. Equal pitch ensures that the spacing between the bidirectional interlocking points in the direction of the main line travel is the same as the spacing between the wave troughs of the corrugated roller in the direction of the main line travel. As the bidirectional interlocking point moves with the main line, its X-direction coordinate position increases synchronously with the X-direction coordinate position of a certain wave trough, and the relative positional relationship between the two remains constant.

[0101] The wavy teeth extend continuously along the axial direction of the roller, forming concentric parallel wavy rings. The axial spacing between the wavy rings is minimal or zero, and the crests and troughs of adjacent wavy rings are continuously aligned axially, forming a continuous crest and trough line along the axial direction. This continuous wavy structure ensures that all bidirectional interlocking points at the double-layer overlapping edge are simultaneously locked by the crests along the entire width of the Y direction, with a uniform locking effect along the axial direction.

[0102] The upper pressure roller 301 and the lower pressure roller 301 are arranged in a complementary mirror image with complementary wavy tooth patterns. The crest of the upper pressure roller 301 corresponds to the trough of the lower pressure roller 301, and vice versa. When the two pressure rollers 301 mesh, the crest of the upper pressure roller 301 inserts into the trough of the lower pressure roller 301, and the crest of the lower pressure roller 301 inserts into the trough of the upper pressure roller 301. The two interlocking with each other form a continuous, alternating peak-to-trough extrusion channel. When the double-layered overlapping edge passes through the wavy roller gap, the bidirectional interlocking point is located at the trough. The trough is the position where the distance between the upper and lower pressure rollers is the largest. After entering the trough, the bidirectional interlocking point is clamped by the crests on both sides from both directions. The crest of the upper pressure roller 301 presses downward from above, and the crest of the lower pressure roller 301 pushes upward from below. The bidirectional interlocking point is subjected to concentrated pressure from the crests on both sides at the trough.

[0103] The lower pressure roller 301 bearing seat is fixedly mounted on the side plate of the frame, while the upper pressure roller 301 bearing seat is installed in a vertical groove on the side plate. The vertical position of the upper pressure roller 301 relative to the lower pressure roller 301 is adjusted via a screw adjustment mechanism or a servo cylinder, thus adjusting the engagement depth. The engagement depth is defined as the depth to which the crests of the two pressure rollers 301 insert into each other's troughs, reflecting the amount of pressure exerted by the crests on the bidirectional interlocking points. The greater the engagement depth, the greater the compressive stress of the crests on the bidirectional interlocking points, and the greater the degree of plastic deformation of the yarn segment. The engagement depth is controlled by adjusting the vertical position of the upper pressure roller 301.

[0104] In this embodiment, the elastic preload roller 5 and the corrugated toothed locking roller 3 are arranged adjacent to each other, forming a spatial basis for sequential coordination. The extremely short time window effectively suppresses the rebound of the yarn segment. The equal pitch of the troughs of the corrugated toothed locking roller 3 with the needle-punching pitch is the geometric basis for phase coupling. The rounded corners of the crests and the adjustment of the engagement depth ensure that the locking force is moderate, allowing the yarn segment to undergo plastic deformation without breaking. The coordinated cooperation of the two rollers realizes a complete process chain from initial interlocking to fixed connection.

[0105] In this embodiment, the phase-coupled synchronous transmission mechanism establishes the transmission relationship between the yarn-pulling needle roller assembly 2 and the wave-tooth pressure-locking roller 3. While maintaining the transmission ratio unchanged, the phase angle is adjusted so that each bidirectional interlocking point falls precisely into the trough position when the dry web moves forward.

[0106] The phase-coupled synchronous transmission mechanism includes a driving synchronous pulley, a driven synchronous pulley, a phase coupling, and a synchronous belt. The driving synchronous pulley is mounted on the lower guide roller 201 shaft of the yarn-drawing needle roller assembly 2, located on the outer side near the edge plate. The driven synchronous pulley is mounted on the lower pressure roller 301 shaft of the wave-tooth pressure-locking roller 3, also located on the outer side near the edge plate. The phase coupling is connected in series in the transmission chain, linking the driving synchronous pulley and the driven synchronous pulley.

[0107] The number of teeth on the active synchronous pulley is determined based on the transmission ratio. The transmission ratio is set so that the trough pitch of the wave-tooth pressure-lock roller 3 is synchronized in time with the needle-punching pitch of the yarn-drawing needle roller assembly 2. Specifically, the transmission ratio is obtained by dividing the circumference of the lower pressure roller 201 by the number of circumferential columns to obtain the needle-punching pitch, and by dividing the circumference of the lower pressure roller 301 by the number of waves to obtain the trough pitch. Since the trough pitch and the needle-punching pitch are equal in space, the transmission ratio is the ratio of the circumferences of the two rollers.

[0108] Taking the needle roller 201 (300mm diameter, 36 circumferential rows) and the pressure roller 301 (150mm diameter, 18 corrugations) as examples: The needle roller 201 has a circumference of 942mm and a needle-punching pitch of 26.2mm; the corrugated roller has a circumference of 471mm and a corrugation pitch of 26.2mm. The transmission ratio is 942mm / 471mm = 2:1, meaning that for every 1 revolution of the needle roller 201, the corrugated roller rotates 2 times. The driving synchronous pulley has 40 teeth, the driven synchronous pulley has 20 teeth, and the transmission ratio is 2:1.

[0109] Phase couplings are used to fine-tune the phase angle between the driving and driven ends while maintaining a constant transmission ratio. Phase couplings are available in pin-hole or disc-type structures. A synchronous belt connects the driving and driven synchronous pulleys, with a phase coupling connected in series. The synchronous belt is toothed, with trapezoidal or circular arc teeth on its inner surface that mesh with the pulley teeth, ensuring slippage during torque transmission. The synchronous belt is made of rubber-reinforced fiber composite material, offering good flexibility and tensile strength. Synchronous belt tension is achieved through a tensioning pulley or by adjusting the center distance between the two pulleys. Appropriate tension ensures that the synchronous belt does not skip teeth or slip during transmission, resulting in high transmission accuracy and low noise.

[0110] Phase calibration is a necessary step before the phase-coupled synchronous transmission mechanism is put into use. Its purpose is to adjust the phase coupling so that the bidirectional interlocking point formed by the yarn-pulling needle roller assembly 2 precisely corresponds spatially to the trough position of the wavy-toothed pressure-locking roller 3. With the machine stopped, manually rotate the yarn-pulling needle roller assembly 2 until a row of blunt-tipped yarn-pulling needles 2011 reaches the roller gap point. At this point, this row of needles corresponds to a certain X-coordinate position on the dry wire, which is the bidirectional interlocking point formation position. Manually rotate the wavy-toothed pressure-locking roller 3 until a certain trough reaches the roller gap point position, and record the corresponding X-coordinate position of the trough. If the X-coordinate position of the bidirectional interlocking point coincides with the X-coordinate position of the trough, the phase angle is correct and no adjustment is needed. If they do not coincide and there is a positional deviation, the phase angle needs to be adjusted.

[0111] The double-layered overlapping edges, carrying the bidirectional interlocking points, enter the meshing zone of the wavy toothed pressure-locking roller 3. At this point, the bidirectional interlocking points have been initially pressed and shaped by the elastic pre-pressing roller 5, and the two layers of dry web remain tightly bonded, with the geometric position of the bidirectional interlocking points stable. At the bidirectional interlocking points, the upper yarn segment is pushed into the lower mesh, and the lower yarn segment is pushed into the upper mesh, with the two yarn segments crossing at the node in a preliminary interlocking state.

[0112] At the bidirectional interlocking point, yarn segments interweave from top to bottom and bottom to top. The upper yarn segment bends downwards from the upper web plane, crosses the contact interface, and enters the lower mesh, supported by the edges of the lower mesh openings. The lower yarn segment bends upwards from the lower web plane, crosses the contact interface, and enters the upper mesh, supported by the edges of the upper mesh openings. The two yarn segments cross in an X-shape at the node. The concentrated pressure from the wave crest acts at the center of the X-shaped cross, and the pressure is simultaneously applied to the intersection of the upper and lower yarn segments, causing both yarn segments to be compressed at the same time.

[0113] The upper yarn segment bends downwards and experiences an upward reaction force, while the lower yarn segment bends upwards and experiences a downward reaction force. Under pressure, the two yarn segments compress each other, increasing the bending angle and decreasing the radius of curvature. At the bend, the yarn segment experiences tensile stress on the outside and compressive stress on the inside. When the stress exceeds the yield stress, irreversible slippage and rearrangement of the molecular chains occur, altering the yarn's microstructure. Macroscopically, this manifests as a change in the yarn's cross-sectional shape from a circular to a flattened cross-section, and the curvature at the bend solidifies.

[0114] When two yarns intersect, they are compressed against each other, generating lateral normal stress that flattens the yarn cross-sections. The upper yarn segment is pressed down from below by the lower yarn segment, and the lower yarn segment is pressed down from above by the upper yarn segment. This causes indentations or deformations in the cross-sections of the two yarns at the intersection, leaving indentations on the yarn surfaces. This lateral flattening effect further enhances the mechanical interlocking of the two yarns.

[0115] The pressure from the crests also causes the interlaced yarn segments to twist at the nodes. The intersection of the two originally independent planes of yarn twists under pressure into a three-dimensional knot structure containing bidirectional interlaced yarns. As the upper yarn segment bends downwards from the upper plane into the lower mesh, the bending angle increases under the crest pressure, and the yarn segment penetrates almost perpendicularly to the original plane to the bottom of the lower mesh. Similarly, as the lower yarn segment bends upwards from the lower plane into the upper mesh, the bending angle also increases under pressure, penetrating to the top of the upper mesh. The two yarn segments form a tightly interlocked knot at the center of the node.

[0116] At the knot, the yarn segment no longer springs back after the pressure is released because the yarn has undergone plastic deformation under pressure, and the molecular chain segments rearrange and solidify the deformed geometry. Polyester yarn exhibits certain creep characteristics during plastic deformation at room temperature; under continuous pressure, the molecular chain segments gradually relax, releasing internal stress and solidifying the deformation.

[0117] After the three-dimensional twisted structure is formed, the bidirectional interlocking points possess multi-dimensional mechanical locking capabilities. In the tensile direction, the upper yarn segment is held in place by the edge of the lower mesh opening, and vice versa; when the two layers of the web are subjected to tension in the X direction, the yarn segments cannot be pulled out of the mesh openings. In the shear direction, the two yarn segments interlock at the node; when the two layers of the web are subjected to shear force in the Y or Z direction, the shear displacement is resisted by the bending stiffness and friction of the interlocking yarns. In the torsional direction, the three-dimensional twisted point serves as the mechanical connection point between the two layers of the web; when subjected to torsional torque, the torsional displacement is resisted by the torsional stiffness of the yarns and the constraint of the mesh opening edges.

[0118] From the bidirectional pushing of the needle roller 201 to the application of plastic locking by the corrugated toothed locking roller 3, the entire time window is the sum of the travel time from the exit of the needle roller 201 to the elastic pre-pressure roller 5 and then to the entrance of the corrugated roller, typically 0.12-1.5 seconds. This time window is much shorter than the characteristic time of the yarn segment rebound process, approximately 2-5 seconds. Within this extremely short time window, the yarn segment rebound has not yet occurred significantly and remains within the mesh of the opposite layer, with the geometric position of the interlocking point stable. In this stable state, the bidirectional interlocking point enters the corrugated toothed locking roller 3 and is subjected to concentrated pressure from the wave crests. The yarn segment undergoes plastic deformation exceeding the yield stress, the deformation solidifies, the elastic potential energy is completely released, the rebound driving force disappears, and the bidirectional interlocking point forms a permanent bond.

[0119] In this embodiment, the device is equipped with an adjustment mechanism to accommodate the thickness differences of paper flocking dry wires of different specifications. Depending on the flocking method, fiber density, and dry wire thickness, the thickness of the double-layered overlapped dry wire varies. The overlap thickness of a single-sided flocked thin dry wire is approximately 1.5-3 mm, while the overlap thickness of a double-sided flocked thick dry wire is approximately 3-6 mm. The operating parameters of the needle roller 201, the elastic pre-pressure roller 5, and the corrugated roller need to be adjusted according to the overlap thickness. The adjustment mechanism includes two options: a manual screw adjustment mechanism and an automatic servo adjustment mechanism.

[0120] The manual screw adjustment mechanism is suitable for applications where the specifications of the paperboard do not change frequently. It features a simple structure, low cost, high reliability, and easy maintenance. The screw drive mechanism is a mature mechanical transmission method, without a complex control system, eliminating the risk of electrical or hydraulic failures, and operates stably in the high-temperature and high-humidity environment of paper mills. The automatic servo adjustment mechanism is suitable for high-end automated production lines and applications requiring rapid switching between multiple product types. The automatic servo adjustment mechanism includes a thickness sensor, a control system, and three servo cylinders. The thickness sensor is installed between the guide groove outlet and the active clamping roller 4, detecting the real-time thickness of the double-layer overlapping edge after folding. The thickness sensor uses either a laser displacement sensor or a contact displacement sensor. The laser displacement sensor is installed above the double-layer overlapping edge, with the laser beam shining vertically downwards onto the upper surface of the edge. The sensor measures the distance from the laser beam to the upper surface. A fixed reference surface is provided below, and the sensor simultaneously measures the distance to the reference surface. The difference between these two distances is the thickness of the double-layer overlapping edge.

[0121] The control system employs a programmable logic controller (PLC) or an industrial computer. The PLC runs an adjustment algorithm program that queries a memory-based adjustment parameter table based on the thickness value to calculate the target positions of the three servo cylinders. The PLC sends control signals to three proportional valves via digital or analog output modules. These proportional valves control the air pressure or flow rate of the servo cylinders, achieving precise control of the piston rod position. The automatic servo adjustment mechanism is more expensive than the manual screw adjustment mechanism due to the addition of components such as thickness sensors, the PLC control system, servo cylinders, and proportional valves, increasing the total equipment cost by approximately 30%-50%. However, in applications requiring rapid switching between multiple product types or extremely high consistency in finishing quality, the increased production efficiency and quality stability brought by the automatic adjustment mechanism far outweigh the increased cost.

[0122] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic edge-sealing device for the flocking process of papermaking wire mesh, characterized in that, The assembly includes a three-dimensional gradient spiral guide groove (1), a yarn-pulling needle roller assembly (2), and a wave-tooth pressure-locking roller (3) arranged sequentially along the direction of the dry web travel. The three-dimensional gradient spiral guide groove (1) is used to fold the edge of the dry web by 180°, so that the two layers of dry web are relatively close to each other to form a double-layer overlapping edge. The yarn-pulling needle roller assembly (2) includes two needle rollers (201) placed vertically opposite each other. Blunt-tipped yarn-pulling needles (2011) are radially distributed on the rim of the needle rollers (201). The blunt-tipped yarn-pulling needles (2011) of the upper needle roller (201) penetrate the double-layer overlapping edge from top to bottom and push the upper dry web. The yarn segment at the mesh node is allowed to pass downward through the contact interface of the two layers of dry net and enter the mesh of the lower dry net. The blunt-tipped yarn-pulling needle (2011) of the lower guide roller (201) penetrates the double-layer overlapping edge from bottom to top and pushes the yarn segment at the mesh node of the lower dry net so that it passes upward through the contact interface of the two layers of dry net and enters the mesh of the upper dry net. When the blunt-tipped yarn-pulling needle (2011) withdraws, the yarn segment remains in the mesh of the opposite layer dry net to form a bidirectional interlocking point. The wave-tooth pressure-locking roller (3) includes two pressure rollers (301) that are opposite each other and have complementary wave-tooth patterns on their roller surfaces, which are used to apply plastic pressure lock to the bidirectional interlocking point.

2. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, An active clamping roller (4) is provided between the three-dimensional gradient spiral guide groove (1) and the yarn-pulling needle roller assembly (2). The active clamping roller (4) includes two rollers (401) that are positioned opposite each other. The two rollers (401) apply a continuous clamping force to the double-layer overlapping edge to maintain the double-layer overlapping edge in a tight fit before entering the yarn-pulling needle roller assembly (2).

3. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, The roller diameter of the needle roller (201), the needle length of the blunt-tipped yarn-pulling needle (2011), and the window angle of the working window are matched to each other, so that the lateral displacement of the arc trajectory of the blunt-tipped yarn-pulling needle (2011) in the working window relative to the dry net is less than the size of a single mesh of the dry net, and the blunt-tipped yarn-pulling needle (2011) completes the action of penetrating and pushing the yarn segment in the same mesh.

4. The automatic edge-sealing device for flocking a mesh blanket according to claim 1, characterized in that, The trough pitch of the wavy toothed pressure-locking roller (3) is equal to the needle pitch formed by the blunt-tipped yarn-drawing needle (2011) in the direction of the dry web travel. The wavy toothed pressure-locking roller (3) and the needle roller (201) are connected by a synchronous transmission mechanism with a phase coupling, which is used to adjust the phase angle between the wavy toothed pressure-locking roller (3) and the needle roller (201) while keeping the transmission ratio constant, so that each bidirectional interlocking point falls into the trough position of the wavy toothed pressure-locking roller (3) when it moves forward with the dry web. When the two pressure rollers (301) mesh, the bidirectional interlocking point located at the trough is subjected to concentrated pressure from the peaks on both sides. The bidirectional interlocking point simultaneously includes yarn segments that interweave from top to bottom and from bottom to top. The concentrated pressure of the peaks causes the interwoven yarn segments to undergo permanent deformation at the node to form a three-dimensional twisted structure, which constitutes plastic pressure lock on the bidirectional interlocking point.

5. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, An elastic pre-pressure roller (5) is provided between the yarn-pulling needle roller assembly (2) and the wave toothed pressure-locking roller (3). The elastic pre-pressure roller (5) applies a continuous normal pressing force to the double-layer overlapping edge carrying the bidirectional interlocking point, which is used to limit the relative displacement of the double-layer overlapping edge and perform preliminary pressing and shaping of the bidirectional interlocking point, so that the bidirectional interlocking point maintains positional accuracy and enters the wave toothed pressure-locking roller (3). The elastic pre-pressure roller (5) and the wave toothed pressure-locking roller (3) are arranged close to each other. After the bidirectional interlocking point is pressed and constrained by the elastic pre-pressure roller (5), it enters the wave toothed pressure-locking roller (3) and completes plastic pressure-locking before the yarn segment rebounds due to its own tension, so as to form a timing coordination of bidirectional pushing and instantaneous pressure-locking.

6. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, The cross-section of the three-dimensional gradient spiral guide groove (1) is three-segmented gradient along the direction of the dry net. The inlet section is a horizontal straight plate with the same width as the edge of the dry net. The middle section is an L-shaped section that guides the edge of the dry net to fold. The outlet section is a C-shaped section that folds the edge of the dry net to 180°. After folding, a double-layered edge is formed. The inner wall of the three-dimensional gradient spiral guide groove (1) is provided with a low-friction coating on the surface that contacts the dry net.

7. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, The upper pressure roller (201), the elastic preload roller (5), and the upper pressure roller (301) of the wave toothed pressure locking roller (3) of the yarn drawing needle roller assembly (2) are respectively provided with a spiral adjustment mechanism, which is used to manually adjust the pressing depth of the upper pressure roller (201), the spring preload of the elastic preload roller (5), and the meshing depth of the upper pressure roller (301) in the stopped state, and is fixed by the locking mechanism after adjustment.

8. The automatic edge-closing device for flocking a mesh blanket according to claim 1, characterized in that, The upper pressure roller (201), the elastic preload roller (5), and the upper pressure roller (301) of the wave toothed pressure-locking roller (3) of the yarn-pulling needle roller assembly (2) are respectively connected to servo cylinders. The control system automatically adjusts the pressing depth of the upper pressure roller (201), the spring preload of the elastic preload roller (5), and the meshing depth of the upper pressure roller (301) according to the thickness value of the double-layer overlapping edge detected by the thickness sensor.

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