A cutting device for overlock machine based on compound cutter
By adopting a composite cutter structure in the fabric cutting device of the overlock sewing machine, and utilizing a combination design of hard alloy and steel, the problem of poor wear resistance of the lower cutter is solved, the cutter life is extended, and the cutting effect and production efficiency are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JACK SEWING MASCH CO LTD
- Filing Date
- 2025-06-11
- Publication Date
- 2026-06-19
AI Technical Summary
The lower cutter in the fabric cutting device of the existing overlock sewing machine has poor wear resistance, resulting in frequent replacement and wear, which affects the cutting effect and production efficiency, and the frictional heat accelerates the shortening of service life.
It adopts a composite cutting structure, with the upper and lower cloth cutting blades made of carbide and steel respectively. The carbide part is used for wear resistance and limiting. The meshing point is designed with alternating contact between the carbide and steel to avoid chipping of the carbide blade and to reduce friction through clearance fit.
It extends the lifespan of the cutter, maintains cutting performance, reduces operating costs and frictional heat generation, and improves production efficiency.
Smart Images
Figure CN224378452U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of overlock sewing machine technology, and in particular to a fabric cutting device for overlock sewing machines based on a composite cutter. Background Technology
[0002] Overlock sewing machines are commonly used industrial sewing equipment in the garment sewing industry. They are mainly used for overlocking, overlocking, and binding of garment edges to prevent the raw edges from fraying and pilling. They can also reinforce the sewing of garment fabrics and can be used for various fabrics such as T-shirts, sportswear, and underwear.
[0003] Currently, overlock sewing machines are equipped with a fabric cutting device to cut the fabric during operation, meeting customers' requirements for neat fabric edges. In existing technology, the fabric cutting device of an overlock sewing machine typically includes a pair of upper and lower cutting blades (moving blades) and a lower cutting blade (fixed blade), and a cutting drive mechanism connected to the upper cutting blades. The cutting drive mechanism drives the upper cutting blades to reciprocate towards or away from the lower cutting blades, achieving meshing and cutting of the fabric by the upper and lower cutting blades. The upper and lower cutting blades are pre-assembled through a process to form a scissor-like cutting effect, ensuring the cutting effect on the fabric.
[0004] However, existing fabric cutting devices for overlock sewing machines have several problems during use: 1. Because the lower cutter is made of a single material of ordinary steel, its wear resistance is poor. As a result, the blade easily becomes dull during cutting, requiring frequent replacement and increasing operating costs. 2. After a period of use, wear on the lower cutter causes changes in the preset gap between the upper and lower cutting blades, leading to a decrease in cutting performance. When cutting thin fabrics, this results in poor cutting quality, leading to burrs, uneven edges, and other sewing defects. In this case, the worn lower cutter needs to be replaced or sharpened and reinstalled, further reducing production efficiency. 3. Friction between the upper and lower cutting blades generates heat. Combined with the poor wear resistance of the ordinary steel lower cutter, this accelerates its wear and shortens its lifespan. Utility Model Content
[0005] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a fabric cutting device for an overlock sewing machine based on a composite cutter, so that both the upper and lower fabric cutting blades have a longer service life.
[0006] To achieve the above objectives, this utility model provides a fabric cutting device for an overlock sewing machine based on a composite cutter, including a movable upper fabric cutting blade, a fixed lower fabric cutting blade, and a cutter driving mechanism. The cutter driving mechanism is connected to the upper fabric cutting blade and drives the upper fabric cutting blade to swing up and down. The upper fabric cutting blade includes an upper blade base and an upper blade shearing part fixed at the lower end of the upper blade base. The lower end of the upper blade shearing part is provided with an upper blade blade and an upper blade guide and limiting part extending downward from the tail of the upper blade blade. The upper blade shearing part is made of hard alloy.
[0007] The lower cutting blade includes a lower cutting edge at the top, and the hardness of the material in the lower cutting blade is lower than the hardness of the upper cutting part.
[0008] During the process of the cutting drive mechanism driving the upper and lower cutting blades to engage, the upper blade guide limit part is close to one side of the lower cutting blade, and at least a portion of the lower cutting blade that is close to the upper blade guide limit part is made of hard alloy.
[0009] Furthermore, in a preferred embodiment of the fabric cutting device of the overlock sewing machine: the lower cutting blade includes a lower blade base and a lower blade limiting part fixed at the top end of the lower blade base, the lower blade is located at the top of the lower blade base and the tail of the lower blade extends to the lower blade limiting part, the material of the lower blade base is steel, and the material of the lower blade limiting part is hard alloy;
[0010] When the upper and lower cutting blades are engaged by the cutting drive mechanism, the tail of the upper blade contactes and engages with the lower blade, and the engagement point of the two is close to the connection between the lower blade base and the lower blade limiting part.
[0011] During the process of the cutting drive mechanism driving the upper and lower cutting blades to mesh, the meshing point of the upper and lower blades is always located at the top of the lower blade base, and the upper blade guide and limiting part is close to one side of the lower blade limiting part.
[0012] Preferably, the upper cutting part and the lower cutting limiting part are both made of tungsten steel or tungsten carbide.
[0013] Preferably, when the upper and lower cutting blades are engaged by the cutting drive mechanism, the distance between the engagement point of the upper blade and the lower blade and the connection point of the lower blade base and the lower blade limiting part is no more than 0.3 mm.
[0014] Furthermore, in another preferred embodiment of the overlock sewing machine fabric cutting device: the lower fabric cutting knife includes a lower blade base and a lower blade shearing limiting part fixed on the top of the lower blade base, the lower blade blade is located on the top of the lower blade shearing limiting part, the material of the lower blade base is steel, and the material of the lower blade shearing limiting part is hard alloy, and its hardness is at least 20% lower than that of the upper blade shearing part;
[0015] During the process of the cutting blade driving mechanism driving the upper and lower cutting blades to engage, the engagement point of the upper blade and the lower blade is always located at the top of the lower blade shearing limit part, and the upper blade guide limit part is close to one side of the lower blade shearing limit part.
[0016] Furthermore, an optional embodiment of the fabric cutting device of the overlock sewing machine is that the lower fabric cutting blade is installed at an angle, moving further downward and further away from the upper blade guide limit part in its thickness direction;
[0017] During the process of the cutting blade driving mechanism driving the upper and lower cutting blades to mesh, a gap is formed between the upper blade guide limiting part and the lower blade base.
[0018] Furthermore, an optional embodiment of the overlock sewing machine fabric cutting device is as follows: the overlock sewing machine fabric cutting device further includes a fixedly arranged lower knife seat, a lower knife frame fixed to the lower knife seat, and a lower knife pressure plate fixed to the end face of the lower knife frame. A lower knife mounting groove is provided on the end face of the lower knife frame, and the lower cutting knife is accommodated in the lower knife mounting groove and pressed between the lower knife frame and the lower knife pressure plate.
[0019] Furthermore, an optional embodiment of the fabric cutting device of the overlock sewing machine is as follows: the cutting drive mechanism includes an upper blade holder shaft, an upper blade seat, a guide pin, and a connecting screw, which are rotatably supported in the housing of the overlock sewing machine. The upper blade holder shaft is used for transmission connection with the main shaft of the overlock sewing machine. A shaft connecting arm extends integrally from the upper blade holder shaft. The end of the shaft connecting arm is engaged with the upper blade seat. The guide pin is rotatably connected in the shaft connecting arm. The upper blade seat and the guide pin are connected by a connecting screw. The upper blade base is fixed to the upper blade seat.
[0020] Preferably, the upper blade base and the upper blade holder are fixed together by fastening screws, and the upper blade base has an adjustment groove extending vertically, with the fastening screws passing through the adjustment groove.
[0021] As described above, the fabric cutting device for an overlock sewing machine based on a composite cutter, as disclosed in this utility model, has the following beneficial effects:
[0022] 1. In the upper cutting blade, the upper cutting part, which has an upper blade edge and an upper blade guide limit part, is made of cemented carbide. Therefore, the upper blade edge and the upper blade guide limit part have excellent wear resistance and high temperature resistance, reducing the wear of the upper cutting part.
[0023] 2. By setting the hardness of the material containing the lower blade edge of the lower cloth cutting knife to be lower than that of the upper blade edge, the lower blade edge has good cutting performance. When the upper and lower blade edges mesh to cut the cloth, the lower blade edge is subjected to force, which effectively prevents the upper blade edge, made of cemented carbide, from chipping and improves the service life of the upper cloth cutting knife.
[0024] 3. During the fabric cutting process, the upper blade guide and limiting part is close to one side of the lower fabric cutting blade to achieve limiting; in this application, at least a portion of the material of the lower fabric cutting blade that contacts the upper blade guide and limiting part is made of hard alloy, so that the part of the fabric cutting blade that contacts the upper blade guide and limiting part also has excellent wear resistance and high temperature resistance, effectively reducing the frictional heat generated during the meshing and cutting process of the upper and lower fabric cutting blades, thereby slowing down the wear of the upper and lower fabric cutting blades, especially the lower fabric cutting blade, so that both the upper and lower fabric cutting blades have excellent durability. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the fabric cutting device of the overlock sewing machine based on the composite cutter of this application.
[0026] Figure 2 for Figure 1 A schematic diagram of the structure of the upper and lower cloth cutting blades when they are just engaged, viewed from another angle.
[0027] Figure 3 for Figure 2 The main view.
[0028] Figure 4 for Figure 3 Enlarged view of circle A.
[0029] Figure 5 for Figure 2 Side view of the upper and middle cutting blade.
[0030] Figure 6 for Figure 2 Side view of the lower middle cutting blade.
[0031] Figure 7 This is a schematic diagram of the second embodiment of the fabric cutting device for an overlock sewing machine based on a composite cutter according to this application.
[0032] Figure 8 for Figure 7 A schematic diagram of the structure of the upper and lower cloth cutting blades when they are just engaged, viewed from another angle.
[0033] Figure 9 for Figure 8 The main view.
[0034] Figure 10 for Figure 9 Enlarged view of circle A.
[0035] Figure 11 for Figure 8 Side view of the upper and middle cutting blade.
[0036] Figure 12 for Figure 8 Side view of the lower middle cutting blade.
[0037] Component designation explanation
[0038] 10. Upper cutting cloth knife
[0039] 11. Upper blade substrate
[0040] 12 Upper blade shearing section
[0041] 121. Upper blade.
[0042] 122 Upper Tool Guide Limiting Part
[0043] 20 Cloth Cutting Knives
[0044] 21. Lower the blade.
[0045] 22. Cutting base
[0046] 23. Cutting limit section
[0047] 24. Lower cutter shearing limit section
[0048] 30 Cutting blade drive mechanism
[0049] 31 Upper tool post shaft
[0050] 311 shaft connecting arm
[0051] 32 Upper Knife Holder
[0052] 33 Guide pins
[0053] 34 Connecting screws
[0054] 41 Lower blade holder
[0055] 42 Lower tool holder
[0056] 43 Lower blade pressure plate
[0057] 50 spindle Detailed Implementation
[0058] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.
[0059] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.
[0060] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.
[0061] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.
[0062] This application relates to the field of overlock sewing machine technology, and in particular to a fabric cutting device for overlock sewing machines based on a composite cutter, used for cutting fabric. For ease of description, the directions in the following embodiments are defined as follows: the axial direction of the main shaft 50 in the overlock sewing machine is defined as the left-right direction, the horizontal direction orthogonal to the left-right direction is defined as the front-back direction, and the vertical direction orthogonal to the left-right direction is defined as the up-down direction; at the same time, the feeding direction of the overlock sewing machine during sewing is the front direction.
[0063] like Figure 1 and Figure 2 As shown, or as Figure 7 and Figure 8As shown, the fabric cutting device for an overlock sewing machine based on a composite cutter according to this application includes a movable upper fabric cutting blade 10, a fixed lower fabric cutting blade 20, and a cutter drive mechanism 30. The cutter drive mechanism 30 is connected to the upper fabric cutting blade 10 and drives the upper fabric cutting blade 10 to swing up and down, causing the upper fabric cutting blade 10 to swing downward toward the lower fabric cutting blade 20 and upward away from the lower fabric cutting blade 20. Therefore, in the fabric cutting device for the overlock sewing machine, the upper fabric cutting blade 10 is a moving blade, and the lower fabric cutting blade 20 is a fixed blade. Furthermore, the upper cutting cloth knife 10 includes an upper knife base 11 and an upper knife shearing part 12 fixed at the lower end of the upper knife base 11. The lower end of the upper knife shearing part 12 is provided with an upper knife blade 121 and an upper knife guide limiting part 122 extending downward from the tail of the upper knife blade 121. The tail of the upper knife blade 121 is also the front end of the upper knife blade 121. The upper knife base 11 is made of steel and the upper knife shearing part 12 is made of cemented carbide. Therefore, the upper cutting cloth knife 10 is a composite material cutting cloth knife made of at least two different materials, and is a composite cutting knife. The lower cutting blade 20 includes a lower cutting edge 21 located at the top. The lower cutting edge 21 extends straight in the front-to-back direction. The hardness of the material in the lower cutting blade 20 where the lower cutting edge 21 is located is lower than the hardness of the upper cutting shearing part 12. During the process of the cutting blade driving mechanism 30 driving the upper cutting blade 10 and the lower cutting blade 20 to engage, the upper cutting blade guide limiting part 122 is close to the right side of the lower cutting blade 20. At least a portion of the material of the part of the lower cutting blade 20 that is close to the upper cutting blade guide limiting part 122 is made of hard alloy. Therefore, the lower cutting blade 20 is a composite material cutting blade made of at least two different materials, and is a composite cutting blade.
[0064] In the fabric cutting device of the overlock sewing machine described above, both the upper cutting blade 10 and the lower cutting blade 20 are composite cutters. When not cutting fabric, the upper blade 121 is located above the lower blade 21, and the two are not engaged. When cutting begins, the cutter drive mechanism 30 drives the upper cutting blade 10 to swing downward, thus engaging the upper cutting blade 10 with the lower cutting blade 20 to cut the fabric; afterwards, the cutter drive mechanism 30 drives the upper cutting blade 10 to swing upward and return to its original position; this process is repeated to cut the fabric. In the upper cutting cloth knife 10, the upper cutting part 12, which is equipped with an upper cutting edge 121 and an upper cutting guide and limiting part 122, is made of cemented carbide. Therefore, both the upper cutting edge 121 and the upper cutting guide and limiting part 122 have excellent wear resistance and high temperature resistance, reducing the wear of the upper cutting part 12. At the same time, the hardness of the material where the lower cutting edge 21 is located in the lower cutting cloth knife 20 is set to be lower than the hardness of the upper cutting edge 121, so the lower cutting edge 21 has good cutting performance. Thus, when the upper cutting edge 121 and the lower cutting edge 21 are engaged to cut the cloth, the lower cutting edge 21 is subjected to force, effectively preventing the upper cutting edge 121, which is made of cemented carbide, from chipping and improving the service life of the upper cutting cloth knife 10. In particular, during the fabric cutting process, the upper blade guide limiter 122 is positioned close to the right side of the lower fabric cutting blade 20 to achieve a limiting effect. In this application, at least a portion of the material of the lower fabric cutting blade 20 that contacts the upper blade guide limiter 122 is made of hard alloy, so that the part of the fabric cutting blade that contacts the upper blade guide limiter 122 also has excellent wear resistance and high temperature resistance, effectively alleviating the frictional heat generated during the meshing and cutting process of the upper fabric cutting blade 10 and the lower fabric cutting blade 20, thereby reducing the wear of the upper fabric cutting blade 10 and the lower fabric cutting blade 20, especially the lower fabric cutting blade 20.
[0065] Therefore, by setting up an upper cutting blade 10 and a lower cutting blade 20 with a composite cutting blade structure, this application effectively alleviates the wear caused by the contact friction and heat generation between the upper cutting blade 10 and the lower cutting blade 20, improves the wear resistance of the upper cutting blade 10 and the lower cutting blade 20, effectively extends the overall service life of the upper cutting blade 10 and the lower cutting blade 20, reduces the cost of use, and reliably maintains the preset gap at the meshing part of the upper cutting blade 10 and the lower cutting blade 20, ensuring the cutting effect.
[0066] The following provides two preferred embodiments of the fabric cutting device for an overlock sewing machine.
[0067] Example 1 of the fabric cutting device for overlock sewing machine
[0068] The preferred structure of the upper cutting blade 10 in Embodiment 1 of the overlock sewing machine fabric cutting device is as follows: Figure 2 and Figure 5As shown, the upper cutting blade 10 includes the aforementioned upper blade base 11 and an upper blade shearing part 12 with an upper blade cutting edge 121 and an upper blade guide and limiting part 122 at its lower end. The upper blade base 11 is made of steel, preferably high-strength steel, and the upper blade shearing part 12 is made of cemented carbide, preferably tungsten carbide or tungsten carbide. The upper blade base 11 and the upper blade shearing part 12 are firmly fixed together by a high-temperature and high-pressure sintering process.
[0069] The preferred structure of the lower cutting blade 20 in Embodiment 1 of the overlock sewing machine fabric cutting device is as follows: Figure 2 and Figure 6 As shown, the lower cutting blade 20 includes a lower blade base 22 and a lower blade limiting part 23 fixed to the top tail end of the lower blade base 22. The tail end of the top of the lower blade base 22 is the front end of the top of the lower blade base 22. The lower blade edge 21 is located on the top of the lower blade base 22, and the tail end of the lower blade edge 21 extends forward to the rear end of the lower blade limiting part 23. The lower blade base 22 is made of steel, preferably high-strength steel, and the lower blade limiting part 23 is made of cemented carbide, preferably tungsten steel or tungsten carbide. The lower blade base 22 and the lower blade limiting part 23 are firmly fixedly connected by a high-temperature and high-pressure sintering process. Therefore, in the first embodiment of the fabric cutting device of the overlock sewing machine, the steel part and the cemented carbide part of the lower cutting blade 20 are arranged side by side in the front-rear direction.
[0070] In Embodiment 1 of the fabric cutting device for the overlock sewing machine, when the cutter drive mechanism 30 drives the upper fabric cutting blade 10 to swing downwards and causes the upper fabric cutting blade 10 to just engage with the lower fabric cutting blade 20, as Figure 2 As shown, the tail of the upper cutting edge 121 contacts and engages with the lower cutting edge 21, and the engagement point is... Figure 2 Point X in the diagram refers to the front end of the upper blade 121; the initial engagement point X between the tail of the upper blade 121 and the lower blade 21 is adjacent to the connection between the lower blade base 22 and the lower blade limiting part 23; in this embodiment, in the front-rear direction, the distance from the initial engagement point X between the tail of the upper blade 121 and the lower blade 21 to the connection between the lower blade base 22 and the lower blade limiting part 23 is no greater than 0.3mm. At this time, the upper blade 121 and the lower blade 21 begin to generate a shearing action, and the fabric begins to be sheared; the boundary line between the steel part and the hard alloy part in the lower cutting cloth knife 20 is partially covered by the upper blade guide limiting part 122. Preferably, in the side view of the lower cutting cloth knife 20, as shown... Figure 6 As shown, the dividing line between the steel part and the cemented carbide part in the lower cutting blade 20 is a dividing line that slopes downwards and backwards.
[0071] Subsequently, as the cutting drive mechanism 30 drives the upper cutting blade 10 to continue swinging downwards, that is, during the process of the cutting drive mechanism 30 driving the upper cutting blade 10 to engage with the lower cutting blade 20, the engagement point of the upper blade 121 and the lower blade 21 moves backwards. Thus, the engagement point of the upper blade 121 and the lower blade 21 is always located at the top of the lower blade base 22. That is, the upper blade 121 is always engaged with the top of the steel lower blade base 22, and will not engage with the top of the carbide lower blade limiting part 23, thus preventing the carbide part on the lower blade 21 from chipping. Meanwhile, during the meshing and cutting process of the upper cutting blade 10 and the lower cutting blade 20, the lower cutting blade 20 is subjected to force, and the lower blade limiting part 23 made of cemented carbide is always in contact with the upper blade guide limiting part 122 made of cemented carbide. Based on the wear-resistant and high-temperature resistant properties of cemented carbide, this structure effectively alleviates the wear caused by the heat generated by contact friction between the two.
[0072] Furthermore, in Embodiment 1 of the overlock sewing machine fabric cutting device, as... Figure 3 and Figure 4 As shown, the lower cutting blade 20 is installed at an angle, with the angle being such that the lower the blade is, the further away it is from the upper blade guide limit part 122 in its thickness direction; that is, the lower cutting blade 20 is tilted to the lower left. With this configuration, during the engagement of the upper cutting blade 10 and the lower cutting blade 20 by the cutting blade drive mechanism 30, a gap is formed between the upper blade guide limit part 122 and the lower blade base 22. This gap prevents direct friction between the upper blade guide limit part 122 and the lower blade base 22, thus avoiding wear caused by frictional heat.
[0073] Example 2 of the fabric cutting device for overlock sewing machine
[0074] In Embodiment 2 of the overlock sewing machine fabric cutting device, the upper fabric cutting blade 10 has the same structure as the upper fabric cutting blade 10 in Embodiment 1. Therefore, as Figure 8 and Figure 11 As shown, the upper cutting blade 10 also includes an upper blade base 11 and an upper blade shearing part 12 with an upper blade blade 121 and an upper blade guide and limiting part 122 at the lower end.
[0075] In Embodiment 2 of the fabric cutting device for the overlock sewing machine, the preferred structure of the lower fabric cutting blade 20 is as follows: Figure 8 and Figure 12 As shown, the lower cutting blade 20 includes a lower blade base 22 and a lower blade shearing limiting part 24 fixed on the top of the lower blade base 22. The lower blade edge 21 is located on the top of the lower blade shearing limiting part 24 and extends back and forth. The lower blade base 22 is made of steel, preferably high-strength steel, and the lower blade shearing limiting part 24 is made of cemented carbide, with a hardness at least 20% lower than that of the upper blade shearing part 12. Therefore, in Embodiment 2 of the fabric cutting device for the overlock sewing machine, the steel part and the cemented carbide part of the lower cutting blade 20 are arranged side by side in the vertical direction.
[0076] In Embodiment 2 of the fabric cutting device for the overlock sewing machine, during the process of the cutter drive mechanism 30 driving the upper fabric cutting blade 10 to swing downward and engaging the upper fabric cutting blade 10 with the lower fabric cutting blade 20, such as Figure 8 As shown, the engagement point between the upper cutting edge 121 and the lower cutting edge 21 is always located at the top of the lower cutting shearing limiting part 24, meaning that the upper cutting shearing part 12 is always engaged with the top of the lower cutting shearing limiting part 24. Since the hardness of the lower cutting shearing limiting part 24 is lower than that of the upper cutting shearing part 12, chipping of the lower cutting shearing limiting part 24 is prevented. Simultaneously, the lower cutting shearing limiting part 24, with the lower cutting edge 21 at its top, is made of cemented carbide, which has excellent wear resistance, making the lower cutting edge 21 less prone to dulling. During the meshing and cutting process of the upper cutting blade 10 and the lower cutting blade 20, the lower cutting blade 20 is subjected to force, and the upper blade guide limit part 122 is close to the right side of the lower blade shearing limit part 24. That is, the lower blade shearing limit part 24 made of cemented carbide is always in contact with the upper blade guide limit part 122 made of cemented carbide. Based on the wear resistance and high temperature resistance of cemented carbide, this structure effectively alleviates the wear caused by contact friction and heat generation between the two.
[0077] Furthermore, in Embodiment 2 of the overlock sewing machine fabric cutting device, as... Figure 9 and Figure 10 As shown, the lower cutting blade 20 is installed at an angle, with the angle being such that the lower the blade is, the further away it is from the upper blade guide limit part 122 in its thickness direction; that is, the lower cutting blade 20 is tilted to the lower left. With this configuration, during the engagement of the upper cutting blade 10 and the lower cutting blade 20 by the cutting blade drive mechanism 30, a gap is formed between the upper blade guide limit part 122 and the lower blade base 22. This gap prevents direct friction between the upper blade guide limit part 122 and the lower blade base 22, thus avoiding wear caused by frictional heat.
[0078] In both embodiments of the fabric cutting device for the overlock sewing machine described above, the lower fabric cutting blade 20 is installed in the same way, preferably as follows: Figure 1 or Figure 7 As shown, the fabric cutting device of the overlock sewing machine also includes a fixedly mounted lower blade holder 41, a lower blade support 42 fixed to the lower blade holder 41, and a lower blade pressure plate 43 fixed to the right end face of the lower blade support 42. A lower blade mounting groove is provided on the right end face of the lower blade support 42. The opening of the lower blade mounting groove faces right and is vertically continuous. The bottom of the left side of the lower blade mounting groove is inclined downwards to the left. The lower cutting blade 20 is housed in the lower blade mounting groove and pressed between the lower blade support 42 and the lower blade pressure plate 43. This achieves an inclined installation of the lower cutting blade 20, with the entire lower cutting blade tilted downwards to the left, creating a gap between the upper blade guide limit part 122 and the lower blade base 22. This avoids direct friction, reduces wear on the lower blade base 22, and extends the service life of the lower cutting blade 20.
[0079] In the two embodiments of the fabric cutting device for the overlock sewing machine described above, the cutter drive mechanism 30 has the same structure, preferably as follows: Figure 1 or Figure 7 As shown, the cutter drive mechanism 30 includes an upper cutter holder shaft 31, an upper cutter seat 32, a guide pin 33 extending to the left and right, and a connecting screw 34 extending to the front and back, all of which are rotatably supported in the housing of the overlock sewing machine via bearings. The upper cutter holder shaft 31 is used for transmission connection with the main shaft 50 of the overlock sewing machine. A shaft connecting arm 311 extends integrally from the left end of the upper cutter holder shaft 31. The end of the shaft connecting arm 311 is engaged with the upper front side of the upper cutter seat 32. The guide pin 33 is rotatably connected in the end of the shaft connecting arm 311 engaged with the upper cutter seat 32. The connecting screw 34 is screwed from the rear side of the upper cutter seat 32 forward into the upper cutter seat 32 and the guide pin 33, so that the upper cutter seat 32 and the guide pin 33 are connected by the connecting screw 34. The upper cutter base 11 is fixed on the left side of the upper cutter seat 32. The main shaft 50 of the overlock sewing machine is driven by a motor to rotate, which in turn drives the upper blade holder shaft 31 to rotate. This, in turn, drives the upper blade holder 32 and the upper cutting blade 10 to swing up and down around the upper blade holder shaft 31 as the central axis, forming an arc-shaped motion trajectory. When the upper blade 121 at the lower end of the upper cutting blade 10 contacts the fabric, it works together with the lower blade 21 to generate a shearing force, cutting the fabric.
[0080] Preferably, the upper blade base 11 and the upper blade holder 32 are fixed together by fastening screws. The upper blade base 11 has an adjustment groove that extends vertically. The fastening screws are inserted into the adjustment groove to adjust the installation height of the upper cutting blade 10, so as to adjust the initial assembly position of the upper cutting blade 10 and the lower cutting blade 20.
[0081] In summary, this utility model effectively overcomes the various shortcomings of the prior art and has high industrial application value.
[0082] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. A fabric cutting device for an overlock sewing machine based on a composite cutter, comprising a movable upper fabric cutting blade (10), a fixed lower fabric cutting blade (20), and a cutter driving mechanism (30), wherein the cutter driving mechanism (30) is connected to the upper fabric cutting blade (10) and drives the upper fabric cutting blade (10) to swing up and down, characterized in that: The upper cutting blade (10) includes an upper blade base (11) and an upper blade shearing part (12) fixed at the lower end of the upper blade base (11). The lower end of the upper blade shearing part (12) is provided with an upper blade blade (121) and an upper blade guide limiting part (122) extending downward from the tail of the upper blade blade (121). The upper blade shearing part (12) is made of hard alloy. The lower cutting blade (20) includes a lower cutting edge (21) at the top. The hardness of the material in the lower cutting blade (20) with the lower cutting edge (21) is lower than the hardness of the upper cutting part (12). During the process of the cutter drive mechanism (30) driving the upper cutter (10) and the lower cutter (20) to engage, the upper cutter guide limit part (122) is close to one side of the lower cutter (20), and at least a portion of the part of the lower cutter (20) that is close to the upper cutter guide limit part (122) is made of hard alloy.
2. The fabric cutting device for an overlock sewing machine according to claim 1, characterized in that: The lower cutting blade (20) includes a lower blade base (22) and a lower blade limiting part (23) fixed at the top end of the lower blade base (22). The lower blade edge (21) is located at the top of the lower blade base (22) and the tail of the lower blade edge (21) extends to the lower blade limiting part (23). The material of the lower blade base (22) is steel, and the material of the lower blade limiting part (23) is hard alloy. When the cutting drive mechanism (30) drives the upper cutting blade (10) and the lower cutting blade (20) to engage, the tail of the upper blade (121) contacts and engages with the lower blade (21), and the engagement point of the two is close to the connection between the lower blade base (22) and the lower blade limiting part (23). During the process of the cutting drive mechanism (30) driving the upper cutting blade (10) and the lower cutting blade (20) to mesh, the meshing point of the upper blade (121) and the lower blade (21) is always located at the top of the lower blade base (22), and the upper blade guide limit part (122) is close to the side of the lower blade limit part (23).
3. The fabric cutting device for an overlock sewing machine according to claim 2, characterized in that: The upper cutting section (12) and the lower cutting limiting section (23) are both made of tungsten steel or tungsten carbide.
4. The fabric cutting device for an overlock sewing machine according to claim 2, characterized in that: When the upper cutting blade (10) and the lower cutting blade (20) are just engaged by the cutting blade drive mechanism (30), the distance between the tail of the upper blade (121) and the engagement point of the lower blade (21) and the connection point of the lower blade base (22) and the lower blade limiting part (23) is no more than 0.3mm.
5. The fabric cutting device for an overlock sewing machine according to claim 1, characterized in that: The lower cutting blade (20) includes a lower blade base (22) and a lower blade shearing limiting part (24) fixed on the top of the lower blade base (22). The lower blade blade (21) is located on the top of the lower blade shearing limiting part (24). The material of the lower blade base (22) is steel, and the material of the lower blade shearing limiting part (24) is hard alloy, and its hardness is at least 20% lower than that of the upper blade shearing part (12). During the process of the cutter drive mechanism (30) driving the upper cutter (10) and the lower cutter (20) to engage, the engagement point of the upper blade (121) and the lower blade (21) is always located at the top of the lower cutter shearing limit part (24), and the upper blade guide limit part (122) is close to one side of the lower cutter shearing limit part (24).
6. The fabric cutting device for an overlock sewing machine according to claim 2 or 5, characterized in that: The lower cutting blade (20) is installed at an angle, moving further downward and further away from the upper blade guide limit part (122) in its thickness direction; During the process of the cutter drive mechanism (30) driving the upper cutter (10) and the lower cutter (20) to engage, a gap is formed between the upper cutter guide limit part (122) and the lower cutter base (22).
7. The fabric cutting device for an overlock sewing machine according to claim 6, characterized in that: It also includes a fixed lower knife holder (41), a lower knife support (42) fixed to the lower knife holder (41), and a lower knife pressure plate (43) fixed to the end face of the lower knife support (42). A lower knife mounting groove is provided on the end face of the lower knife support (42). The lower cutting cloth knife (20) is housed in the lower knife mounting groove and is pressed between the lower knife support (42) and the lower knife pressure plate (43).
8. The fabric cutting device for an overlock sewing machine according to claim 1, characterized in that: The cutter drive mechanism (30) includes an upper cutter holder shaft (31), an upper cutter seat (32), a guide pin (33), and a connecting screw (34) rotatably supported in the housing of the overlock sewing machine. The upper cutter holder shaft (31) is used for transmission connection with the main shaft (50) of the overlock sewing machine. An integral shaft connecting arm (311) extends from the upper cutter holder shaft (31). The end of the shaft connecting arm (311) is engaged with the upper cutter seat (32). The guide pin (33) is rotatably connected in the shaft connecting arm (311). The upper cutter seat (32) and the guide pin (33) are connected by the connecting screw (34). The upper cutter base (11) is fixed to the upper cutter seat (32).
9. The fabric cutting device for an overlock sewing machine according to claim 8, characterized in that: The upper blade base (11) and the upper blade holder (32) are fixed together by fastening screws. The upper blade base (11) has an adjustment groove extending vertically, and the fastening screw passes through the adjustment groove.