A step-by-step shearing stripping type threshing cutter assembly and threshing method suitable for small pieces of tobacco leaves

Abstract

This invention discloses a step-by-step shearing and peeling leaf-beating blade assembly and method adapted for small tobacco leaves. It includes parallel and dynamically coordinated moving and fixed beating blades, with several moving and fixed beating blade units interlaced circumferentially along the rotation axis to form a continuous shearing pair structure. Each beating blade unit is divided into an installation section and a functional section along its length. The functional section includes a cutting edge area and a grinding area. The cutting edge area has a protruding blade at its root, and the grinding area has a rough working surface. During leaf beating, the moving beating blade rotates, and the blades of the moving and fixed beating blade units form staggered cuts on both sides of the tobacco leaf, preserving a continuous, uncut area. Subsequently, the grinding area applies a tearing action in opposite directions, causing the leaf pulp tissue to peel off along the fiber texture of the tobacco stem. This invention solves the problems of easy slippage, incomplete separation, and high breakage rate when beating small tobacco leaves, achieving orderly and gentle separation of the leaf pulp and tobacco stem, improving the integrity of the tobacco leaf and the yield of the finished product.

Description

Technical Field

[0001] This invention belongs to the field of leaf threshing and re-drying production technology, specifically relating to a step-by-step shearing and peeling leaf threshing knife assembly and leaf threshing method adapted to small tobacco leaves. Background Technology

[0002] In the tobacco processing industry, leaf threshing and re-drying is a core process in the front end of cigarette production. The core function of the leaf threshing process is to effectively separate the leaf pulp from the stems after the initial curing, remove mixed hard stems and miscellaneous stems, and grade the tobacco leaves to produce qualified tobacco sheets and pure stems, providing standardized raw materials for subsequent tobacco processing.

[0003] In existing conventional production processes, after pretreatment steps such as sorting and impurity removal, rehydration, and uniform loosening of the raw tobacco, it is quantitatively fed and continuously fed in the form of whole tobacco leaves. After the material enters the leaf threshing machine, it relies on the combined action of rigid shearing, mechanical impact, and friction tearing between the moving and fixed blades and the frame to tear and break up the whole tobacco leaves and separate the stems. The separated tobacco leaves and stems are screened and air-classified before being transported to the re-drying, leaf storage, stem storage, and subsequent shredding sections, and finally prepared into tobacco raw materials that meet the requirements of cigarette making.

[0004] In recent years, slim and medium-sized cigarettes have experienced rapid growth and their market share has continued to increase. These cigarette products place more stringent demands on the uniformity, length specifications, filling value, and combustion stability of the tobacco shreds. The tobacco shred sizes suitable for traditional coarse cigarettes can no longer meet the production needs of slim and medium-sized cigarettes. To produce standardized products with lengths and widths smaller than traditional tobacco shreds, smaller tobacco sheets must be obtained as raw materials before the leaves are shredded. To this end, the industry generally adopts a multi-stage, multi-pass leaf-beating processing mode. By repeatedly adjusting the gap between the beating blades, optimizing the air classification parameters, and increasing the frequency of beating and sorting, more small-sized tobacco sheets are passively produced. Then, with the assistance of multi-stage slicing and secondary cutting at the back end, the narrow width and short length tobacco shred size standards required for slim cigarettes are indirectly matched.

[0005] However, after repeated threshing, forceful tearing, and mechanical compression, tobacco leaves suffer from severe material breakage, with a significant increase in the proportion of waste tobacco fragments and small pieces. This results in a marked decrease in the yield of high-quality, usable tobacco sheets, leading to a serious waste of raw tobacco materials. At the same time, excessive mechanical action can easily cause stem breakage and leaf fiber damage, resulting in a loose structure and increased impurity content in the finished tobacco product. This not only increases production energy consumption and equipment maintenance costs but also directly affects the stability of cigarette taste and the consistency of product quality, making it difficult to meet the requirements of fine raw materials for slim and medium-sized cigarettes.

[0006] To avoid the serious breakage defects caused by repeated leaf threshing at the source, the industry currently performs directional pre-cutting on whole tobacco leaves before they enter the threshing process. This cuts the original whole tobacco leaves into smaller pieces of tobacco raw material, about one-third to one-quarter the size of the standard size. This shortens the tearing and separation process in the subsequent threshing process, reduces the number of times the blades strike the leaves repeatedly, reduces the degree of mechanical breakage of the tobacco leaves, and improves the efficiency and uniformity of the tobacco shreds in the subsequent shredding process.

[0007] However, existing threshing equipment and blades are designed and configured for whole tobacco leaves. The pre-cut tobacco leaves, resulting in small areas and fragments, are smaller in size, lighter in weight, and have a more compact structure where the stem and leaf tissue are joined, with a much smaller contact area than a whole tobacco leaf. Existing threshing machine blades and frame structures are designed for use with whole tobacco leaves, with the blade body being a single, flat plate with a continuous, straight cutting edge. This type of plate-shaped blade operates at a single point of force application, making it difficult to effectively constrain small tobacco flakes. The flakes easily slip and slide directly through the blade's gaps, failing to provide continuous and effective mechanical action at the stem-leaf junction, thus hindering stable stem-leaf separation. A significant proportion of material passes through the blade gaps before the stem-leaf junction receives sufficient mechanical action, leading to incomplete stem-leaf separation, severe stem-leaf mixing, poor separation uniformity, and the potential for unnecessary breakage due to excessive localized stress on the tobacco leaves. It is difficult to balance separation efficiency with tobacco leaf integrity.

[0008] To address the above problems, this invention is proposed. Summary of the Invention

[0009] In view of the shortcomings of existing technologies, such as the easy slippage of small pre-cut tobacco leaves during leaf threshing, incomplete separation of stems and leaves, high tobacco leaf breakage rate, and low material utilization rate, as well as the single structure of traditional flat plate blades, poor constraint on small tobacco leaves, rough mechanical action, and difficulty in balancing separation efficiency and tobacco leaf integrity, the purpose of this invention is to provide a step-by-step shearing and peeling leaf threshing blade assembly and leaf threshing method adapted to small tobacco leaves.

[0010] This invention sets the functional sections of the cutting tool along its length as a cutting edge area and a grinding area, so that the moving and fixed cutting edges form staggered cuts on both sides of the tobacco leaf. Then, the moving and fixed grinding areas apply a tearing action to the tobacco leaf in opposite directions. This step-by-step method of staggered cuts and reverse tearing is different from the traditional whole synchronous tearing mode of leaf beating, and achieves a gentle and directional separation of leaf pulp and tobacco stem.

[0011] At the same time, it effectively reduces the probability of small tobacco leaves slipping through, reduces material breakage caused by excessive impact and strong compression, improves the uniformity of stem and leaf separation and the qualified rate of small tobacco leaf finished products, reduces raw material loss and equipment operation and maintenance costs, and meets the fine processing needs of small-sized tobacco leaf raw materials for slim and medium cigarette production.

[0012] The technical solution adopted in this invention is:

[0013] The first aspect of the present invention provides a step-by-step shearing and stripping leaf-cutting blade assembly adapted to small tobacco leaves, including at least a pair of parallel and dynamically coordinated moving blades 1 and fixed blades 2; the moving blades 1 can rotate at a constant speed around a rotation axis, the fixed blades 2 are fixedly arranged, and the two are arranged in a linear array of moving blade units 11 and fixed blade units 21 interlaced along the rotation axis to form a continuous shearing pair structure, and there is an operating gap between the moving blades 1 and the fixed blades 2 to accommodate the passage of small tobacco leaves;

[0014] The moving blade unit 11 and the fixed blade unit 21 are divided into an installation section 3 and a functional section 4 along the length of the blade body from the root to the free end. The overall thickness of the functional section 4 gradually increases from the root to the free end. The functional section 4 is divided into a cutting edge area 41 and a grinding area 42 along the direction away from the installation section 3. The cutting edge area 41 is provided with a cutting edge 411 near the root of the installation section 3.

[0015] The moving blade unit 11 and the fixed blade unit 21 are divided into a blade face side 6 and a blade back side 7 along the width direction of the blade body. The thickness of the blade body gradually increases from the blade face side 6 to the blade back side 7. The grinding area 42 is located on the surface of the blade face side 6, which is a rough working surface.

[0016] The surfaces of the cutting edge area 41 of the moving cutting edge unit 11 and the fixed cutting edge unit 21 are provided with gradually raised arc-shaped cutting edges from the root near the mounting section 3 toward the free end, so that the cutting edge 411 protrudes from its respective cutting edge surface; the grinding area 42 of the moving cutting edge unit 11 and the fixed cutting edge unit 21 gradually increases in thickness and gradually narrows in width from the end near the cutting edge area 41 toward the free end, so that the free end of the grinding area 42 forms the rough working surface on the cutting edge side 6, and its width is narrower than the width of the root of the cutting edge area 41.

[0017] When the moving blade 1 rotates, the cutting positions of the blade 411 of the moving blade unit 11 and the blade 411 of the fixed blade unit 21 on the two opposite surfaces of the tobacco leaf are staggered along the extension direction of the tobacco leaf, forming staggered cuts on both sides of the tobacco leaf; the grinding area 42 of the moving blade unit 11 rotates synchronously with the moving blade 1, while the grinding area 42 of the fixed blade unit 21 remains stationary. The two apply a tearing action to the tobacco leaf in opposite directions, causing the leaf tissue to peel off from the surface of the tobacco stem along the tobacco stem fibers.

[0018] Preferably, the ratio of the length of the cutting edge area 41 along the length of the blade body to the length of the grinding area 42 along the length of the blade body is 1:3 to 1:4.

[0019] Preferably, the cutting edge 411 is independently protruding from the surface of the cutting edge area 41 and extends obliquely towards the free end along the length of the blade body; the thickness of the cutting edge 411 gradually decreases from one end near the mounting section 3 to the end of the free end, forming a cutting edge structure that is obliquely tilted forward.

[0020] Preferably, there are two moving blades 1 and one fixed blade 2; the two moving blades 1 are arranged parallel and equidistantly on both sides of the fixed blade 2.

[0021] Preferably, the rough working surface is a diamond layer covering the surface of the grinding zone 42 located on the cutting edge side 6.

[0022] Preferably, the blade back side 7 maintains a uniform thickness along the length of the blade body, forming a continuous structural support ridge; the mounting section 3 is integrally formed at the end of the blade back side 7 near the root of the blade body; the moving blade unit 11 and the fixed blade unit 21 are integrally formed structures.

[0023] Preferably, the moving cutter unit 11 and the fixed cutter unit 21 are arranged alternately along the rotation axis, and adjacent moving cutter units 11 and fixed cutter units 21 form a shearing operation gap that is continuously distributed in the circumferential direction.

[0024] Preferably, the cuts formed on both sides of the tobacco leaf by the blade 411 of the moving cutter unit 11 and the blade 411 of the fixed cutter unit 21 are staggered along the extension direction of the tobacco leaf, and a continuous uncut connection area is retained between the opposing ends of the two cuts.

[0025] Preferably, the particle size of the diamond layer ranges from 60 mesh to 120 mesh.

[0026] A second aspect of the present invention provides a step-by-step shearing and peeling method for threshing small tobacco leaves, employing the step-by-step shearing and peeling threshing blade assembly described in the first aspect, comprising the following steps:

[0027] Step (1): The small pieces of tobacco leaves to be processed are conveyed to the shearing area formed between the moving blade 1 and the fixed blade 2;

[0028] Step (2): Drive the moving cutter 1 to rotate, so that the blade 411 of the moving cutter unit 11 and the blade 411 of the fixed cutter unit 21 perform cutting at positions that are staggered back and forth along the extension direction of the tobacco leaf on two opposite surfaces, forming staggered cuts on both sides of the tobacco leaf.

[0029] Step (3): The tobacco leaves pre-cut in step 2 rotate into the grinding zone 42 along with the moving blade 1. The grinding zone 42 of the moving blade unit 11 rotates synchronously with the moving blade 1, while the grinding zone 42 of the fixed blade unit 21 remains stationary. The two apply a tearing action to the tobacco leaves in opposite directions, causing the leaf tissue to peel off from the surface of the tobacco stem along the tobacco stem fibers.

[0030] The beneficial effects of this invention are:

[0031] 1. This invention addresses the material characteristics of small pre-cut tobacco leaves by redesigning the overall structure of the cutting tool. The tool body is divided into an installation section and a functional section, with the cutting edge area and grinding area arranged sequentially in the functional section. This abandons the traditional flat plate structure and one-time tearing operation mode of leaf-cutting tools. The curved cutting edge protrudes and is combined with the forward-tilting cutting edge structure to effectively conform to the shape of small tobacco leaves, increase the contact limiting effect, and eliminate the problems of small tobacco leaves being lightweight, easy to slip, and easy to pass through and leak material, thus greatly improving the stability of leaf-cutting operations for small tobacco leaves.

[0032] 2. This invention employs a step-by-step disintegration method combining staggered local incisions with reverse grinding and tearing. The moving and stationary blades form staggered incisions on both sides of the tobacco leaf, while maintaining a continuous connection area between the two incisions to prevent the tobacco leaf from being completely cut off. Based on the stress formed by the incisions, the reverse friction and tearing action of the rotating grinding zone and the stationary grinding zone is used to achieve directional peeling along the direction of the tobacco stem fibers, replacing the traditional rough beating method. This effectively reduces the breakage and dust generation of tobacco leaves, significantly reduces the material breakage rate, and improves the finished product qualification rate and raw material utilization rate of small tobacco leaves.

[0033] 3. This invention rationally proportions the length dimensions of the cutting edge area and the grinding area, while setting the grinding area as a width-converging structure and providing a diamond-coated rough working surface on the blade side, taking into account both local shearing and cutting capabilities and friction peeling effects; the blade body adopts a gradually thickening structure from the blade face to the blade back, with a continuous support ridge of equal thickness on the blade back side, combined with an overall one-piece molding design, which greatly improves the overall rigidity, bending strength and structural stability of the tool, allowing it to adapt to high-speed continuous operation for a long time, and is not prone to deformation, wear and damage, thus reducing equipment maintenance and replacement costs.

[0034] 4. This invention adopts a symmetrical layout of two moving blades on both sides and a fixed blade in the middle. The blade units are staggered along the rotation axis, forming a continuous circumferential shearing gap, which has strong coverage and good processing uniformity. It can effectively solve the defects of traditional blades such as incomplete separation of stems and leaves, mixing of stems and leaves, and poor processing consistency. It is suitable for the processing needs of pre-cut small tobacco leaves and can stably produce small tobacco sheets with uniform specifications. It can better match the raw material production standards of slim and medium cigarettes and effectively expand the adaptability range of leaf-cutting equipment to tobacco leaf materials of different specifications.

[0035] 5. The present invention has a compact structure and clear operation logic. The matching leaf threshing method is simple and easy to implement. It does not require major modification of existing leaf threshing equipment, and the modification investment is low and the practicality is strong. While ensuring the efficiency of stem and leaf separation, it takes into account the integrity of tobacco leaves and processing quality. It reduces auxiliary processes such as multiple repeated leaf threshing and secondary cutting from the source, reduces production energy consumption and process flow, and has good industrial promotion and application value. Attached Figure Description

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 is a schematic diagram of the overall structure assembly of a step-by-step shearing and peeling leaf-beating knife assembly adapted to small tobacco leaves according to the present invention.

[0038] Figure 2 is a schematic diagram of the single-unit structure and segmented structure of the moving cutter unit and the fixed cutter unit of the present invention;

[0039] Figure 3 is a schematic diagram of the working state of the moving and fixed cutting units of the present invention in the form of staggered shearing and reverse peeling. The downward arrow represents the staggered cutting direction of the cutting edge, and the upward arrow represents the direction of the grinding zone's reverse tearing and peeling action on the tobacco leaf.

[0040] Reference numerals: 1-moving striker, 11-moving striker unit; 2-fixed striker, 21-fixed striker unit; 3-installation section; 4-functional section, 41-cutting edge area, 42-grinding area; 411-cutting edge; 6-blade face side; 7-blade back side. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to embodiments, but this is not intended to limit the invention. Any modifications or improvements made based on the teachings of the present invention fall within the protection scope of the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product manual.

[0042] Example 1

[0043] As shown in Figures 1 to 3, this embodiment provides a step-by-step shearing and peeling leaf-beating blade assembly adapted for small tobacco leaves, including a fixed beating blade 2 located in the middle, and two movable beating blades 1 arranged parallel to the fixed beating blade 2 and equidistantly on both sides of it. The two movable beating blades 1 are respectively mounted on their respective beating rollers and can rotate uniformly around their respective rotation axes, with the two rotation axes being parallel to each other; the fixed beating blade 2 is fixedly arranged.

[0044] A working gap adapted to the thickness of small tobacco leaves is provided between the moving blade 1 and the fixed blade 2. This working gap also provides a clearance for the moving and fixed blades to move around. The working gap is designed such that when a small tobacco leaf is sucked into the gap by the rotating moving blade 1, the two opposite surfaces of the tobacco leaf can simultaneously contact the blade surfaces of the moving blade 1 and the fixed blade 2 respectively. The blade 411 first bites into both sides of the tobacco leaf and cuts an off-center cut, limiting and holding the tobacco leaf in the working area. The rough working surface of the subsequent grinding zone 42 continues to hold the tobacco leaf and performs reverse tearing and peeling. After the leaf pulp and tobacco stem are completely separated, the tobacco leaf and tobacco stem material that have lost the clamping force are discharged from the working gap by the rotating airflow and mechanical conveying action, and enter the subsequent screening and air separation processes.

[0045] The moving cutter 1 and the fixed cutter 2 are arranged in a linear array along the rotation axis, with several moving cutter units 11 and fixed cutter units 21 staggered in sequence. When the moving cutter 1 rotates, each moving cutter unit 11 and fixed cutter unit 21 forms a continuous and uninterrupted shearing pair in the axial direction, ensuring that the tobacco leaves falling into the working area can be engaged and processed by at least one set of moving cutter units 11 and fixed cutter units 21 regardless of their axial position, without any processing dead zones or material leakage gaps.

[0046] The moving blade units 11 on the two moving blades 1 are installed in the same direction, and the blades 411 of each moving blade unit 11 face the rotation direction of the moving blade 1, that is, the blade face 6 is set facing forward towards the rotation direction to ensure that the blades 411 contact the tobacco leaves first when rotating. The fixed blade units 21 on the fixed blade 2 are divided into two groups, corresponding to the moving blades 1 on both sides respectively; the fixed blade units 21 located on one side of the fixed blade 2 form one group, and their blades 411 are set facing the rotation direction of the moving blade 1 on that side; the fixed blade units 21 located on the other side of the fixed blade 2 form another group, and their blades 411 are set facing the rotation direction of the moving blade 1 on the other side. The moving blade units 11 on both sides are opposite to the blade face 6 of the corresponding fixed blade units 21 on the same side, and the working gap is formed between the opposite blade face 6.

[0047] The moving cutter unit 11 and the fixed cutter unit 21 have the same structure. For example... Figure 2 As shown, taking the moving blade unit 11 as an example, along the length of the blade body, it is divided into an installation section 3 and a functional section 4 from the root of the blade body towards the free end. The installation section 3 is used to fix the blade body onto the beating roller, and its thickness is greater than the thickness of the functional section 4 near the installation section 3, providing installation rigidity and overall structural stability for the blade. The functional section 4 is the main part that performs the leaf-beating operation, and along the direction away from the installation section 3, it consists of a cutting edge area 41 and a grinding area 42.

[0048] The blade body is divided into a face side 6 and a back side 7 along its width. The face side 6 faces the tobacco leaf, and the back side 7 faces away from the tobacco leaf. The thickness of the blade body gradually increases from the face side 6 to the back side 7, that is, the face side is the thinnest and the back side is the thickest. The back side 7 maintains a constant thickness along the length of the blade body, forming a continuous structural support ridge that provides overall rigidity to the entire blade body and prevents bending deformation during high-speed rotational shearing and tearing. The mounting section 3 is integrally formed at the end of the back side 7 near the root of the blade body. The thickness of the mounting section 3 is consistent with the thickness of the equal-thickness part of the back side 7. The entire moving blade unit 11 or the fixed blade unit 21 is an integrally formed structure without any splicing seams, ensuring continuous force transmission.

[0049] The overall thickness of functional segment 4 gradually increases from the root to the free end. The cutting edge area 41 is located near the root of mounting segment 3. The side surface of the blade at this location gradually bulges away from mounting segment 3, forming an arc-shaped cutting edge segment that constitutes the cutting edge 411. The thickness of the arc-shaped cutting edge segment gradually decreases from its root to its tip, making its thinnest point the thinnest point of the entire blade body. This thinnest point protrudes obliquely towards the free end, forming a forward-leaning cutting tip structure. The end of the arc-shaped cutting edge segment smoothly transitions to the remaining portion of the cutting edge area 41, and the thickness of the remaining portion of the cutting edge area 41 continues to gradually increase towards the free end, eventually naturally connecting with the surface of the grinding area 42. While protruding from the blade surface, the arc-shaped cutting edge has a sharp tip for gentle pre-cutting, and the overall structure, which gradually thickens from the root to the free end, provides continuous support for the cutting edge, preventing stress concentration caused by abrupt changes in thickness.

[0050] The grinding zone 42 is located on the free end side of functional section 4. The grinding zone 42 gradually increases in thickness and gradually narrows in width from the end near the cutting edge area 41 towards the free end. The surface of the grinding zone 42 on the blade side 6 forms a rough working surface, which can extend appropriately along the width of the blade towards both side walls as needed. The rough working surface is a layer of diamond abrasive covering the surface of the grinding zone 42 on the blade side 6, with a particle size ranging from 60 mesh to 120 mesh. The surface of the back side 7 of the grinding zone 42, as well as the two side walls between the back side 7 and the blade side 6, remain smooth and are not covered with a diamond abrasive layer to avoid unnecessary frictional damage to the detached tobacco leaves during the tearing process.

[0051] The ratio of the length of the cutting edge area 41 along the length of the blade to the length of the grinding area 42 along the length of the blade is 1:3 to 1:4. This ratio ensures that the cutting edge area 41 only forms local shallow cuts on both sides of the tobacco leaf, with a small pre-cutting range that does not penetrate the entire tobacco leaf; the grinding area 42 occupies most of the length of the functional section 4, providing sufficient tearing and peeling stroke, allowing the leaf tissue sufficient working distance and time to achieve full dissociation along the fiber texture.

[0052] The following combination Figure 3This section explains the working principle of the tool assembly in this embodiment.

[0053] Small pieces of tobacco leaves to be processed fall from above the moving cutter 1 and the stationary cutter 2. As the moving cutter 1 rotates, the falling tobacco leaves are drawn into the working gap between the moving cutter 1 and the stationary cutter 2 by the suction airflow generated by the rotating moving cutter 1. Because the blade 411 of the moving cutter unit 11 protrudes from the blade surface and has a forward-leaning blade tip structure, it first contacts one side of the tobacco leaf surface during rotation, using the thin blade at the end of the blade 411 to cut the first local cut on that side edge of the tobacco leaf. As the moving cutter 1 continues to rotate, the tobacco leaf is driven to move along the direction of rotation, and the blade 411 of the stationary cutter unit 21 then contacts the other side of the tobacco leaf surface, cutting the second local cut on the other side edge of the tobacco leaf. Because the height of the blade 411 protruding from the blade surface and the angle of its oblique extension are the same as those of the blade 411 of the stationary cutter unit 21, but the two are spatially offset along the extension direction of the tobacco leaf, the two cuts form a mutually offset relationship on both sides of the tobacco leaf. A continuous, uncut connection area is left between the opposing ends of the two cuts, so that the tobacco leaf is not completely cut off during the pre-cutting stage.

[0054] After the cut is formed, the tobacco leaf continues to move forward with the rotating blade 1, entering the working range of the grinding zone 42. The grinding zone 42 of the moving blade unit 11 rotates synchronously with the moving blade 1 at the same speed, and the diamond abrasive layer on the surface of its blade side 6 applies a continuous frictional force along the direction of rotation to the upper surface of the tobacco leaf; the grinding zone 42 of the fixed blade unit 21 is stationary, and the diamond abrasive layer on its surface applies a continuous frictional force opposite to the direction of rotation to the lower surface of the tobacco leaf. The moving and fixed grinding zones simultaneously apply tearing forces to the tobacco leaf in opposite directions. Due to the stress concentration formed at the edges of the two misaligned cuts, the tearing force is concentrated on the continuous uncut connection area between the two cuts. Under the action of continuous reverse tearing force, the leaf tissue in this connection area is gradually and directionally torn apart along the fiber texture of the tobacco stem and peeled off from the surface of the tobacco stem. As the tobacco leaf moves towards the free end of the grinding zone 42, the width of the grinding zone 42 gradually converges, and the tearing force gradually concentrates in a narrower area, finally completing the complete separation of the leaf tissue and the tobacco stem at the free end of the grinding zone 42. After separation, the tobacco flakes and stems lose the gripping force of the blades on both sides and are discharged from the working gap by the rotating airflow and mechanical conveying action, entering the subsequent screening and air classification processes.

[0055] The entire process is completed in steps: "misaligned pre-cutting in the cutting edge area → reverse tearing in the grinding area," which differs from the single tearing mode of traditional leaf-beating blades that lack differentiation. In the pre-cutting stage, misaligned cuts are only formed in local areas of the tobacco leaf, preserving the overall continuity of the tobacco leaf without cutting it. In the tearing stage, the stress concentration effect of the cut is used to directionally peel off the leaf tissue along the fiber texture of the tobacco stem, achieving orderly and gentle separation of the leaf tissue from the tobacco stem. This effectively overcomes the shortcomings of traditional leaf-beating blades, such as insufficient force points and difficulty in effectively tearing small tobacco leaves, while avoiding the problem of the tobacco leaf being cut off as a whole and torn into pieces in a disorderly manner.

[0056] Example 2

[0057] This embodiment provides a step-by-step shearing and peeling method for threshing small tobacco leaves, using the step-by-step shearing and peeling threshing blade assembly described in Embodiment 1, specifically including the following steps:

[0058] Step (1): The small tobacco leaves obtained from the pre-cutting process are continuously fed into the feed inlet above the moving cutter 1 and the fixed cutter 2. Under the action of gravity, the small tobacco leaves fall naturally to the top of the shearing working area formed between the moving cutter 1 and the fixed cutter 2, and are then quickly carried into the working gap by the suction airflow generated by the rotating moving cutter 1. The small tobacco leaves are made by directional pre-cutting of whole tobacco leaves, and the overall size is reduced to one-third to one-quarter of the original whole tobacco leaf, forming small tobacco leaf raw materials.

[0059] Step (2): Drive the moving cutter 1 to rotate at a preset speed (e.g., 800-1200 rpm) at a uniform speed. When the small tobacco leaf enters the shearing area, the moving cutter 1 has at least four sets of moving cutter units 11 arranged circumferentially and uniformly linearly distributed along the axis, which circumferentially pass through the working area in sequence, while the fixed cutter unit 21 on the fixed cutter 2 remains stationary. The blade 411 of the moving cutter unit 11 protrudes from the blade surface and has a forward-leaning blade tip structure. During the rotation, it first contacts the edge surface of one side of the tobacco leaf and uses the sharp blade tip to cut the first shallow cut on the edge of the tobacco leaf. The cutting depth is limited by the protrusion height of the blade area 41. As the moving cutter 1 continues to rotate and drive the tobacco leaf forward, the blade 411 of the fixed cutter unit 21 cuts the second shallow cut at the corresponding position on the other side edge of the tobacco leaf. Because the blades of the moving and fixed cutting units are staggered in the direction of tobacco leaf extension, the two cuts form an asymmetrical staggered structure; the ratio of the length of the cutting edge area 41 to the grinding area 42 along the length of the blade body is 1:3-1:4. The two cuts are partial cuts, and a continuous uncut connection area is reserved between the opposing ends of the two cuts to ensure that the tobacco leaf is intact and not cut or separated during the pre-cutting stage.

[0060] Step (3): After being pre-cut by the misalignment, the tobacco leaves continue to move forward with the rotating moving blade, synchronously entering the working range of the grinding zone 42. The grinding zone 42 of the moving blade unit 11 rotates synchronously with the beating roller. The rough working surface of the blade is set with diamond abrasive and adheres to one side of the tobacco leaf to form an effective grip, applying frictional force in the direction of rotation. The grinding zone 42 of the fixed blade unit 21 remains stationary, and its diamond abrasive layer adheres to the other side of the tobacco leaf to apply reverse frictional force. Relying on the double-sided clamping constraint of the rough working surfaces on both the moving and fixed sides, the tobacco leaf offset, twisting and slippage are restricted, keeping the tobacco leaf posture fixed, thereby forming a continuous and stable reverse pulling and tearing action. The tearing load is concentrated on the continuous connecting section between the two misaligned cuts. With the help of the stress concentration effect formed by the cut edge, the tobacco leaf is clamped and locked by the upper and lower double rough surfaces, the overall posture is stable, the overall force direction is controllable, and the tearing will preferentially extend along the inherent anisotropic fiber direction of the tobacco leaf and the weak interface of the stem and leaf, thereby achieving controlled directional tearing and avoiding disorderly breakage and excessive fragmentation of the tobacco leaf. The grinding zone 42 has a gradually narrowing width from the edge zone towards the free end. The tobacco leaf first contacts the wider initial section of the grinding zone, ensuring sufficient initial contact area and stable gripping. As the tobacco leaf moves towards the free end of the grinding zone, the effective contact area gradually decreases, the tearing load continuously accumulates, and the unit force increases progressively. Simultaneously, the gripping area narrows, matching the gradual peeling rhythm, enabling the leaf tissue to gradually separate from the stem surface from the shallow to the deep layer, ultimately achieving complete separation of stem and leaf at the narrow end of the grinding zone. The separated tobacco leaf and stem are no longer subject to double-sided gripping and are discharged from the working gap by the rotating airflow and the material conveying action of the equipment, and sent to the downstream screening and air separation processes for grading and collection.

[0061] This threshing method employs a step-by-step operation mode combining edge-staggered shallow cutting with reverse friction peeling. The pre-cutting process only performs localized incision limiting and stress induction, preventing the overall cutting of tobacco leaves. Subsequent gentle dissociation is achieved through fiber-directed tearing. Compared to the traditional threshing equipment's processing mode of simultaneous strong tearing and multi-stage repeated impact crushing, this solution can effectively separate the stems and leaves of small tobacco leaves in a single step-by-step operation, significantly reducing the number of times the tobacco leaves are subjected to impact, compression, and strong tearing. This reduces the breakage rate of small tobacco leaves from the source, effectively improving the processing adaptability, leaf integrity, and finished product yield of small-sized pre-cut tobacco leaves.

[0062] It should be noted that the placement of small tobacco leaves during the working interval has a certain degree of randomness. This equipment achieves inherent adaptability through structural optimization: the blades 411 of the moving blade unit 11 and the blades 411 of the fixed blade unit 21 are set in a fixed axially offset layout. The relative offset relationship of the two sides of the cut is determined by the blade structure size and is not affected by the angle of tobacco leaf feeding or the placement posture. At the same time, the double-sided rough working surface of the moving and fixed grinding zones can quickly clamp and stabilize the tobacco leaf at the moment of blade engagement, restricting material twisting and displacement, and keeping the subsequent tearing force in a fixed direction. Relying on the anisotropy of tobacco fiber and the weak bonding interface between stem and leaf, adaptive directional peeling is achieved, ensuring stable separation effect under conventional random feeding conditions.

[0063] Furthermore, the operating conditions can be optimized through upstream process auxiliary feeding design: for example, adding airflow jetting and flat-laying guide structures to the front-end conveying section, using directional airflow and regularized material guiding and limiting, allows small tobacco leaves to enter the shearing operation area in an orderly manner with a flat and spread-out posture. Under the regularized feeding state, the blade engagement position and force angle are more reasonable, and the coordination effect of staggered pre-cutting and reverse tearing is better, which can further improve the uniformity of stem and leaf separation and reduce the proportion of materials with extreme postures.

[0064] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of this application; the dimensions described in the drawings and embodiments are not related to the specific physical object and are not used to limit the protection scope of this application. The physical dimensions can be selected and changed according to actual needs.

Claims

1. A step-by-step shearing and peeling leaf-cutting blade assembly adapted to small tobacco leaves, characterized in that, It includes at least one pair of parallel and dynamically coordinated moving blades (1) and fixed blades (2); the moving blades (1) can rotate at a constant speed around the rotation axis, and the fixed blades (2) are fixedly arranged. The two are arranged in a linear array of moving blade units (11) and fixed blade units (21) along the rotation axis to form a continuous shearing pair structure, and there is an operating gap between the moving blades (1) and the fixed blades (2) to accommodate the passage of small tobacco leaves; The moving blade unit (11) and the fixed blade unit (21) are divided into an installation section (3) and a functional section (4) along the length of the blade body from the root to the free end. The overall thickness of the functional section (4) gradually increases from the root to the free end. The functional section (4) is divided into a cutting edge area (41) and a grinding area (42) along the direction away from the installation section (3). The cutting edge area (41) is provided with a cutting edge (411) near the root of the installation section (3). The moving cutting unit (11) and the fixed cutting unit (21) are divided into a cutting face side (6) and a cutting back side (7) along the width direction of the blade body. The thickness of the blade body gradually increases from the cutting face side (6) to the cutting back side (7). The surface of the grinding area (42) located on the cutting face side (6) is a rough working surface. The surfaces of the cutting edge area (41) of the moving cutting edge unit (11) and the fixed cutting edge unit (21) are provided with gradually raised arc-shaped cutting edge segments from the root near the mounting section (3) towards the free end, through which the cutting edge (411) protrudes from their respective cutting edge surfaces; the grinding area (42) of the moving cutting edge unit (11) and the fixed cutting edge unit (21) gradually increases in thickness and gradually narrows in width from one end near the cutting edge area (41) towards the free end, so that the free end of the grinding area (42) forms the rough working surface on the cutting edge side (6), and its width is narrower than the width of the root of the cutting edge area (41); When the moving blade (1) rotates, the cutting positions of the blade (411) of the moving blade unit (11) and the blade (411) of the fixed blade unit (21) on the two opposite surfaces of the tobacco leaf are staggered along the extension direction of the tobacco leaf, forming staggered cuts on both sides of the tobacco leaf; the grinding area (42) of the moving blade unit (11) rotates synchronously with the moving blade (1), while the grinding area (42) of the fixed blade unit (21) remains stationary. The two apply a tearing action to the tobacco leaf in opposite directions, causing the leaf tissue to peel off from the surface of the tobacco stem along the tobacco stem fibers.

2. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, The ratio of the length of the cutting edge area (41) along the length of the blade body to the length of the grinding area (42) along the length of the blade body is 1:3 to 1:

4.

3. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, The cutting edge (411) is independently protruding from the surface of the cutting edge area (41) and extends obliquely towards the free end along the length of the blade body; the thickness of the cutting edge (411) gradually decreases from the end near the mounting section (3) to the end of the free end, forming a cutting edge structure that is obliquely tilted forward.

4. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, There are two moving blades (1) and one fixed blade (2); the two moving blades (1) are arranged parallel and equidistantly on both sides of the fixed blade (2).

5. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that... The rough working surface is a diamond layer covering the surface of the grinding area (42) located on the blade side (6).

6. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, The blade back side (7) maintains a constant thickness along the length of the blade body, forming a continuous structural support ridge; the mounting section (3) is integrally formed at the end of the blade back side (7) near the root of the blade body; the moving blade unit (11) and the fixed blade unit (21) are integrally formed.

7. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, The moving cutter unit (11) and the fixed cutter unit (21) are arranged alternately along the rotation axis, and a shearing operation gap is formed between adjacent moving cutter units (11) and fixed cutter units (21) in a continuous circumferential distribution.

8. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 1, characterized in that, The cutting edges (411) of the moving cutting unit (11) and the cutting edges (411) of the fixed cutting unit (21) are staggered along the extension direction of the tobacco leaf on both sides, and a continuous uncut connection area is retained between the opposing ends of the two cutting edges.

9. The step-by-step shearing and peeling leaf-cutting blade assembly according to claim 5, characterized in that, The particle size range of the diamond layer is 60 mesh to 120 mesh.

10. A step-by-step shearing and peeling method for threshing small tobacco leaves, employing the step-by-step shearing and peeling threshing blade assembly as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Step (1): The small pieces of tobacco leaves to be processed are conveyed to the shearing area formed between the moving blade (1) and the fixed blade (2); Step (2): Drive the moving cutter (1) to rotate, so that the blade (411) of the moving cutter unit (11) and the blade (411) of the fixed cutter unit (21) perform cutting at a position that is staggered in front and behind on the two opposite surfaces of the tobacco leaf along the extension direction of the tobacco leaf, forming staggered cuts on both sides of the tobacco leaf. Step (3): The tobacco leaves pre-cut in step (2) rotate into the grinding zone (42) along with the moving blade (1). The grinding zone (42) of the moving blade unit (11) rotates synchronously with the moving blade (1), while the grinding zone (42) of the fixed blade unit (21) remains stationary. The two apply a tearing action to the tobacco leaves in opposite directions, causing the leaf tissue to peel off from the surface of the tobacco stem along the tobacco stem fibers.

Images