A sewing machine capable of adjusting the tension of sewing thread

Abstract

The present invention relates to the technical field of sewing machines, and in particular to a sewing machine with an adjustable sewing thread tension. The sewing machine comprises a sewing machine housing and a machine needle. The sewing machine housing is provided with a thread take-up mechanism, which comprises a main thread clamp, a secondary thread clamp, a thread take-up hook, and a thread passing rod. The sewing thread passes through the secondary thread clamp, the main thread clamp, the thread take-up hook, and the thread passing rod in sequence before being input into the machine needle. The secondary thread clamp comprises an electromagnet, a thread clamping part, an adjustment part, and a bearing member, and the bearing member comprises a sleeve part. The adjustment part comprises an adjustment knob and a second spring. One end of the second spring abuts against the thread clamping part, and the other end abuts against the adjustment knob. The adjustment knob squeezes the second spring, causing the second spring to push the thread clamping part. When the electromagnet is energized, the output shaft drives the push rod part to squeeze the thread clamping part. Thus, when facing situations such as facing fabrics of different thicknesses and different stitch lengths, the tension of the sewing thread can be controlled more flexibly and accurately.

Description

Technical Field

[0001] The invention relates to the technical field of sewing machines, in particular to a sewing machine with an adjustable sewing thread tension. Background Art

[0002] The thread clamp of a sewing machine is an important component of the sewing machine. Most sewing machines on the market now have two thread clamps. The main thread clamp is used to clamp the thread end, so as to ensure that the sewing thread can smoothly enter the spool and ensure the sewing effect. The secondary thread clamp is used to clamp the thread during sewing thread input. It can adjust the length of the thread end left on the needle after thread cutting. If there is too long thread end left on the needle after thread cutting, it is very easy to cause a "bird's nest" in the subsequent sewing work, resulting in the sewing seams not being smooth and beautiful, resulting in reduced product quality.

[0003] Both the main thread tensioner and the auxiliary thread tensioner can adjust the tension of the sewing thread. When sewing different materials, adjusting the tension of the sewing thread can also make sewing work more convenient.

[0004] The current technology has the following shortcomings:

[0005] 1. Both the main and auxiliary thread tensioners are adjusted by manually tightening or loosening screws, or tightened by a simple electromagnet structure. The tightening function is not controllable. When faced with a complex sewing process, the stitches will change, making it difficult to achieve beauty and uniformity.

[0006] 2. For the main thread tensioner, the common method now is to use two turntables to clamp the sewing thread to tighten the sewing thread. This control method is not precise enough. When facing fabrics of different thicknesses and different stitch lengths, it is impossible to accurately control the tension and loosening of the sewing thread.

[0007] 3. For the electromagnet clamping solution, when the electromagnet is energized and pushes the iron core, the force generated causes the iron core to push the limit block, which in turn moves the wire release plate. The wire release plate then pushes the spring, which no longer exerts pressure on the wire clamping piece, causing the two wire clamping pieces to separate, thereby achieving the purpose of loosening the wire. Relying on the elastic force generated by the compression spring to apply to the wire clamping piece, the electromagnet acts as the power source throughout the entire process, requiring long working hours, causing the electromagnet to heat up and cause unstable wire tension. Summary of the Invention

[0008] The object of the present invention is to provide a sewing machine capable of adjusting the tension of a sewing thread, thereby being able to flexibly and accurately control the tension of the sewing thread.

[0009] The purpose of the invention is achieved in this way:

[0010] A sewing machine capable of adjusting the tension of sewing thread, comprising a sewing machine housing and a machine needle, wherein a thread feeding mechanism is provided on the sewing machine housing, and the thread feeding mechanism comprises a main thread tensioner, a secondary thread tensioner, a thread take-up hook and a thread take-up lever; the sewing thread passes through the secondary thread tensioner, the main thread tensioner, the thread take-up hook and the thread take-up lever in sequence, and then is fed into the machine needle; the secondary thread tensioner comprises

[0011] an electromagnet, which serves as a power source;

[0012] A thread clamping portion, which is used to clamp the sewing thread;

[0013] an adjusting portion capable of adjusting the force applied by the thread clamping portion to the sewing thread;

[0014] One end of the sleeve portion is a loading end, and the other end is a positioning end; the wire clamping portion is inserted into the sleeve portion from the loading end;

[0015] The adjusting portion includes an adjusting knob and a second spring; the adjusting knob is threadably mounted on the bearing member and is close to the insertion end of the sleeve portion; one end of the second spring abuts against the wire clamping portion, and the other end abuts against the adjusting knob; the adjusting knob squeezes the second spring, causing the second spring to push the wire clamping portion;

[0016] The output shaft of the electromagnet passes through the sleeve portion and extends out of the insertion end; a push rod portion is mounted on the output shaft, the push rod portion faces the wire clamping portion, and a through hole or a slot for the push rod portion to pass through is provided on the bearing member;

[0017] When the electromagnet is energized, the output shaft drives the push rod to squeeze the wire clamping part.

[0018] Preferably, the load-bearing member further comprises:

[0019] A guide post mounted on a receiving end of the sleeve portion;

[0020] The guide column surface and the adjustment knob are threaded together;

[0021] A second through hole is provided in the middle of the guide post, or a second empty groove is provided on the surface of the guide post;

[0022] The adjusting knob is formed with a second fixing groove; one end of the second spring is arranged in the second fixing groove, and the other end of the second spring rests on the wire clamping part.

[0023] Preferably, the push rod portion includes a connecting sleeve and a plurality of plug-in arms; the plug-in arms are arranged on the peripheral side of the connecting sleeve, and the plug-in arms face the wire clamping portion;

[0024] A second empty slot matching the plug-in arm is formed on the guide column, so that the plug-in arm can extend into the second empty slot;

[0025] The push rod part is sleeved on the output shaft, and an adjusting nut 2 is provided on the outside of the push rod part and is fixedly installed on the output shaft; the adjusting nut 2 is used to limit the position of the push rod part on the output shaft.

[0026] Preferably, the guide column includes a central seat body and a plurality of arc-shaped leaves arranged on the circumference of the central seat body; a second empty groove is formed between two adjacent arc-shaped leaves, and the surface of the arc-shaped leaves is provided with external threads;

[0027] One end of the arc-shaped leaf extends to the outside of the middle seat body and forms a concave area; the connecting sleeve of the top rod portion is entirely placed in the concave area; the plug arm extends from the concave area into the corresponding empty slot 2;

[0028] The clamping part is a rotating clamping disc; the second spring and the push rod are used to form the rotation resistance of the clamping disc;

[0029] or,

[0030] The thread clamping part is composed of two thread clamping pieces; the two thread clamping pieces cooperate with each other to clamp the sewing thread; the second spring and the push rod are used to form the clamping force of the two thread clamping pieces;

[0031] The bearing member is fixed to the housing of the electromagnet as a whole, or the bearing member is formed integrally with the electromagnet housing of the electromagnet.

[0032] Preferably, the main thread clamp is an electric thread clamp, and the main thread clamp comprises:

[0033] A driving motor is formed with a rotating shaft, and the driving motor directly or indirectly drives the rotating shaft to rotate. The driving motor is arranged in the sewing machine housing;

[0034] A winding device is provided with a winding area for winding the sewing thread;

[0035] When the shaft rotates, the winding device rotates along with the shaft;

[0036] When the winding device rotates in the first direction, the winding device drives the sewing thread to supply the needle;

[0037] When the winding device rotates in the second direction, the winding device tightens the sewing thread between the needle and the winding device;

[0038] The first direction and the second direction are opposite to each other;

[0039] The winding device is rotatably mounted on the rotating shaft, and a damping mechanism is provided between the winding device and the rotating shaft; when relative rotation occurs between the winding device and the rotating shaft, the damping mechanism sets the rotation resistance of the winding device in the first direction and the second direction.

[0040] Preferably, the winding area is an annular area arranged on the surface of the winding device, and the vertical cross-section of the annular area is an inwardly concave U-shape or V-shape.

[0041] Preferably, the winding device is in the shape of a disk, and a winding area is provided on the circumferential surface of the disk;

[0042] The winding device includes two turntables, each turntable is in a boss shape; the middle part of the turntable is a base part, the outer part of the turntable is a circular ring part, and a plurality of inclined connecting ribs are provided between the base part and the circular ring part, and an empty groove is formed between two adjacent connecting ribs;

[0043] The two base parts are close together and rotate synchronously, and the two annular parts are arranged on the outside;

[0044] The connecting ribs of the two turntables cooperate to form an angle, and the angle surrounds a circle to form a winding area;

[0045] The center of the base is sleeved on the rotating shaft and can rotate;

[0046] The outer side of the base portion is abutted against a damping mechanism, which is fixed on the rotating shaft.

[0047] Preferably, the damping mechanism comprises a clamping member, a spring 1 and an adjusting nut 1;

[0048] The clamping component includes a first clamping part and a second clamping part; the first clamping part is arranged on the rotating shaft and abuts against one of the base parts; the second clamping part is arranged on the rotating shaft and squeezes the other base part from the other side; one end of spring one abuts against the second clamping part, and the other end of spring one abuts against adjusting nut one; adjusting nut one is rotatably installed on the rotating shaft and is threadedly connected to the rotating shaft. By changing the position of adjusting nut one on the rotating shaft, the pressure applied to spring one can be changed.

[0049] Preferably, the second clamping portion includes a retaining ring;

[0050] A second fixing groove is provided in the middle of the rotating shaft; the second fixing groove extends inwardly from the end where the adjusting nut is installed to the base portion along the length direction of the rotating shaft;

[0051] The retaining ring and the pressure plate are both formed with a through hole 1, a crossbeam is formed in the through hole 1, and the size of the crossbeam matches the second fixing groove so that the crossbeam can slide in the second fixing groove;

[0052] The pressure plate is pressed tightly against the base portion;

[0053] A wire felt is provided between the pressing plate and the base portion.

[0054] Preferably, the middle of the connecting rib is formed into a bent portion, and the bent portion protrudes from the base portion;

[0055] When the two turntables are connected into one, the connecting arms of the two turntables are staggered so that the bent portion of one turntable can be embedded in the empty slot of the other turntable;

[0056] The bending portion divides the connecting rib into a first obliquely extending portion and a second obliquely extending portion; the first obliquely extending portion is located outside the second obliquely extending portion;

[0057] Two adjacent first oblique extensions cooperate to form a V-shaped winding area;

[0058] A certain gap is provided between two adjacent first obliquely extending portions.

[0059] Compared with the prior art, the present invention has the following outstanding and beneficial technical effects:

[0060] 1. The main thread clamp in this technical solution rotates by means of a winding device composed of two turntables, and the rotation of the turntable drives the sewing thread to move. In this process, since the sewing thread is wound on the outside of the winding device, it will be affected by the limitation of the rotating shaft and its own tension. The sewing thread is not easy to move and is cheap, and the thread feeding is more uniform and stable. By manually adjusting the adjusting nut, the position of the adjusting nut on the rotating shaft can be changed to cause the spring to be displaced to different degrees, thereby applying different pressures to the winding device, changing the resistance encountered when the turntable rotates, and changing the thread feeding amount. In this way, when facing situations such as fabrics of different thicknesses and different stitch lengths, the tension of the sewing thread can be controlled more flexibly and accurately.

[0061] 2. The main thread tensioner is equipped with a motor, which can directly or indirectly drive the two turntables to rotate, and can actively control the sewing thread to loosen or tighten the thread, so that the sewing thread can be controlled more accurately according to parameters such as fabric thickness and stitch length.

[0062] 3. This technical solution has good adaptability to the thickness of sewing materials and the stitch length of sewing machines, so it can be upgraded with most sewing machines on the market. At the same time, due to its simple structure, the modification cost is low and it is also easy to install.

[0063] 4. In this technical solution, the adjusting knob of the auxiliary thread clamp is connected to the moving iron core, which is inserted into the sleeve part, and the thread clamping part is sleeved on the outside of the sleeve part. When the electromagnet is energized, it can not only indirectly drive the adjusting knob to move, increase the deformation of the spring, and achieve the purpose of increasing the pressure on the thread clamping part; as the ejector part itself moves, part of its position will also come into contact with the thread clamping part, and can directly squeeze the thread clamping part, directly applying additional pressure to the thread clamping part. When it is necessary to cut the thread, the electromagnet is energized, and the magnetic force generated by the coil drives the moving iron core to move in the direction of the electromagnet, so that the ejector part can push the guide column and drive the adjusting nut to quickly compress the spring. At the same time, the plug-in arm of the connecting sleeve will also move and eventually rest against the thread clamping part, applying pressure to the thread clamping part. By applying pressure to the thread clamping part simultaneously by the plug-in arm and the spring, the thread clamping part can generate enough pressure to clamp the sewing thread. The tighter the thread clamp is, the tighter the thread is stretched during trimming. The more the thread retracts after trimming, the shorter the thread ends remaining on the needle. When the electromagnet is de-energized, the core is no longer attracted by the magnetic force generated by the coil, and the spring's elastic force pushes the adjustment knob, which in turn moves the guide post connected to the adjustment knob. Because the spring's deflection is reduced, the pressure on the thread clamp is also reduced, preventing the thread from being clamped too tightly.

[0064] 5. In this technical solution, the ejector pin of the auxiliary clamp can drive the load-bearing component to move. During the operation, the adjusting nut, connecting sleeve and guide column have a larger contact area, which can effectively disperse the pressure and avoid damage to the parts due to excessive pressure.

[0065] 6. In the present technical solution, the sleeve portion of the auxiliary thread clamp is formed with a step portion 1, which can limit the position of the guide column on the sleeve portion, thereby limiting the maximum pressure exerted by the adjustment portion on the spring, and avoiding the situation where the sewing thread cannot be released in time due to excessive pressure on the thread clamping portion after the electromagnet stops being energized, thereby affecting subsequent sewing work.

[0066] 7. When sewing flat materials, the secondary thread tensioner in this technical solution only requires the adjustment knob and spring to apply force to the thread clamping portion. In this state, the electromagnet is not energized. The electromagnet is only energized when passing through the thread, so the operating time is short and it is not easy to heat up. In addition, when it is not working, the clamping force is provided by the spring, so the thread tension is relatively stable and easy to adjust using the adjustment knob. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a structural schematic diagram of the present invention.

[0068] Figure 2 It is a schematic diagram of the route of the sewing thread when the thread feeding mechanism of the present invention is working.

[0069] Figure 3 It is a structural diagram of the secondary clamp of the present invention.

[0070] Figure 4 It is a cross-sectional view of the auxiliary clamp of the present invention.

[0071] Figure 5 It is an exploded view of the thread clamping portion and the adjusting portion of the auxiliary thread clamp of the present invention.

[0072] Figure 6 1 is an exploded view of the bearing member of the secondary clamp of the present invention.

[0073] Figure 7 It is an exploded view of the electromagnet of the secondary thread clamp of the present invention.

[0074] Figure 8 It is a structural schematic diagram of the main clamp of the present invention.

[0075] Figure 9 It is a cross-sectional view of the main clamp of the present invention.

[0076] Figure 10 for Figure 9 Enlarged view of point A in the middle.

[0077] Figure 11 1 is an exploded view of the main clamp of the present invention.

[0078] Figure 12 It is a structural diagram of the turntable of the main tensioner of the present invention.

[0079] Figure 13 It is a structural diagram of the winding device of the main clamp of the present invention.

[0080] Figure 14 for Figure 13 Enlarged view of point B in the middle.

[0081] Reference numerals: 1, sewing machine housing; 11, main thread tensioner; 12, needle; 13, thread take-up hook; 14, thread take-up lever; 15, sewing thread;

[0082] 2. Winding device; 21. Turntable; 22. Base; 23. Annular portion; 24. First slot; 25. Connecting rib; 251. First oblique extension; 252. Second oblique extension; 26. Bend; 27. Winding area; 28. Gap;

[0083] 3. Drive motor; 31. Rotating shaft; 32. Fixing slot 1; 4. Adjusting nut 1; 5. Clamping member; 51. Through hole 1; 52. Crossbeam; 6. Second clamping part; 61. Pressing plate; 62. Stop ring; 63. Spring 1; 64. Wire felt; 7. First clamping part; 71. Washer;

[0084] 8. Secondary clamp; 81. Electromagnet; 811. Electromagnet housing; 812. Magnet cover; 813. Position limiting cavity; 814. Bearing groove 1; 815. Bearing 1; 816. Shock-absorbing pad; 817. Position limiting hole; 818. Fixed coil; 819. Step portion 2;

[0085] 82. Wire clamping part; 821. Wire clamping piece 1; 822. Wire clamping piece 2; 823. Gasket;

[0086] 83. Adjustment unit; 831. Adjustment knob; 832. Second fixing slot; 833. Second spring;

[0087] 84. Load-bearing member; 840. Guide column; 841. Second slot; 842. Middle seat; 843. Arc-shaped leaf; 844. Concave area; 845. Second through hole;

[0088] 85, moving iron core; 851, limiting portion; 852, locking portion; 853, output shaft;

[0089] 86, static iron core; 861, bearing groove 2; 862, bearing 2; 863, convex ring;

[0090] 87. Push rod; 871. Connecting sleeve; 872. Connecting arm; 873. Second adjusting nut; 874. Fixing hole; 875. Fixing screw; 88. Wire guide plate;

[0091] 89. Sleeve portion; 891. Positioning end; 892. Insertion end; 893. Step portion 1; 894. Wide diameter section; 895. Narrow diameter section. DETAILED DESCRIPTION

[0092] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0093] like Figures 1-6 A sewing machine with enhanced thread clamping and convenient adjustment of the tension of a sewing thread 15 is shown, comprising a sewing machine housing 1 and a needle 12. The sewing machine housing 1 is provided with a thread feeding mechanism comprising a main thread tensioner 11, a secondary thread tensioner 8, a thread take-up hook 13, and a thread take-up lever 14. The sewing thread 15 passes sequentially through the secondary thread tensioner 8, the main thread tensioner 11, the thread take-up hook 13, and the thread take-up lever 14 before being fed into the needle 12.

[0094] The auxiliary clamp 8 includes

[0095] an electromagnet 81 serving as a power source for the secondary clamp 8;

[0096] A thread clamping portion 82 for clamping the sewing thread 15;

[0097] The adjusting portion 83 is capable of adjusting the force applied by the thread clamping portion 82 to the sewing thread 15

[0098] a bearing member 84 including a sleeve portion 89;

[0099] like Figures 1-11 As shown, the auxiliary wire clamp 8 includes an electromagnet 81, a wire clamping portion 82, an adjusting portion 83 and a bearing member 84;

[0100] The bearing member 84 includes a sleeve portion 89, one end of the sleeve portion 89 is a loading end 892, and the other end is a positioning end 891. During assembly, the clamping portion 82 is inserted into the sleeve portion 89 from the loading end 892 and moved to the positioning end 891.

[0101] The adjusting knob 831 is screw-mounted on the bearing member 84 and is close to the insertion end 892 of the sleeve portion 89 ; one end of the second spring 833 abuts against the wire clamping portion 82 , and the other end abuts against the adjusting knob 831 .

[0102] The electromagnet 81 is arranged on the bearing member 84 and is adjacent to the positioning end 891 of the sleeve portion 89; the output shaft 853 of the electromagnet 81 passes through the sleeve portion 89 and extends out of the loading end 892; a push rod portion 87 is installed at the end of the output shaft 853, and the push rod portion 87 faces the wire clamping portion 82, and a through hole 845 or a slot 841 is provided on the bearing member 84 for the push rod portion 87 to pass through.

[0103] When the electromagnet 81 is energized, the magnetic force generated by the electromagnet 81 will drive the output shaft 853 to move. As the output shaft 853 moves, the push rod part 87 will drive the adjustment part 83 to move, increasing the pressure applied by the spring 2 833 on the thread clamping part 82, so that the thread clamping piece 1 821 and the thread clamping piece 2 822 can tightly clamp the sewing thread.

[0104] Because the tighter the thread clamp is, the tighter the sewing thread 15 is stretched during trimming. This leads to a greater degree of thread retraction after trimming, and the shorter the thread ends remaining on the needle 12. This reduces the length of thread ends remaining on the needle 12 after trimming, preventing the appearance of "bird's nests" during sewing, which can reduce product quality and aesthetics. Therefore, the electromagnet 81 only operates during the thread cutting process. Most of the time, the electromagnet 81 is not energized, resulting in a shorter operating time and less heat generation.

[0105] like Figure 1-Figure 7 As shown, the load-bearing member 84 also includes

[0106] The guide post 840 is mounted on the insertion end 892 of the sleeve portion 89 .

[0107] The surface of the guide column 840 is threadedly engaged with the adjusting knob 831 .

[0108] A second through hole 845 is provided in the middle of the guide post 840 , or a second empty groove 841 is provided on the surface of the guide post 840 .

[0109] The adjusting knob 831 is sleeved on the guide post 840, and the adjusting knob 831 and the guide post 840 are threadedly engaged. Since the adjusting knob 831 is threadedly connected to the outside of the supporting member 84, the adjusting knob 831 can be rotated to change its position on the supporting member 84, thereby adjusting the deformation of the second spring 833, thereby controlling the pressure exerted by the second spring 833 on the clamping portion 82.

[0110] The adjusting knob 831 is formed with a second fixing groove 832. The other end of the second spring 833 is disposed in the second fixing groove 832, so that the adjusting knob 831 squeezes the second spring 833, causing the second spring 833 to push the wire clamping portion 82. By rotating the adjusting knob 831 to change its position on the bearing member 84, the deformation of the second spring 833 can be changed, thereby adjusting and controlling the wire clamping pressure.

[0111] like Figure 1-Figure 7 As shown, the push rod portion 87 includes a connecting sleeve 871 and a plurality of plug-in arms 872 formed on the connecting sleeve 871. In this technical solution, there are three plug-in arms 872, which are arranged on the circumference of the connecting sleeve 871. When assembled, the plug-in arms 872 face the wire clamping portion 82.

[0112] A second slot 841 that matches the plug-in arm 872 is formed on the guide column 840 , so that the plug-in arm 872 can extend into the second slot 841 .

[0113] like Figure 1-Figure 7 As shown, guide post 840 includes a central base 842 and a plurality of curved lobes 843 disposed around the central base 842. In this embodiment, three curved lobes 843 are formed, with a slot 841 formed between each two adjacent curved lobes 843. External threads are provided on the surfaces of the curved lobes 843. An adjustment knob 831 is sleeved onto the outer sides of the curved lobes 843 and engages with the external threads.

[0114] The plug-in arm 872 formed on the connecting sleeve 871 matches the second empty slot 841, so that the plug-in arm 872 can extend into the second empty slot 841. When the connecting sleeve 871 moves, the plug-in arm 872 can move in the second empty slot 841. However, due to the restriction of the second empty slot 841, the connecting sleeve 871 can only move along the direction of the second empty slot 841 and is not prone to rotation, thereby ensuring the stability of the auxiliary clamp 8 during operation.

[0115] One end of the arc-shaped leaf 843 extends to the outside of the middle seat body 842 and forms a concave area 844; the connecting sleeve 871 of the top rod part 87 can be placed in the interior of the concave area 844 as a whole, and the plug-in arm 872 extends from the concave area 844 into the corresponding empty slot 2 841.

[0116] Furthermore, when the electromagnet 81 is started, the electromagnet 81 will absorb the output shaft 853 and move the output shaft 853 toward the direction of the electromagnet 81. The push rod portion 87 provided on the output shaft 853 will also move together with the output shaft 853. When the push rod portion 87 moves, it will come into contact with the guide column 840, and the plug-in arm 872 will first enter the second slot 841. As the connecting sleeve 871 continues to move, the main body of the connecting sleeve 871 will enter the concave area 844. Through the cooperation of the connecting sleeve 871 and the guide column 840, it is possible to ensure that each component moves on the same axis, thereby increasing the stability of the auxiliary clamp 8 during operation, improving accuracy, making it less likely to deviate, and avoiding the occurrence of jamming between the various parts.

[0117] At the same time, the concave area 844 increases the travel of the connecting sleeve 871, allowing the plug arm 872 to continue to move with the connecting sleeve, and eventually the plug arm can abut against the thread clamping portion 82, directly applying pressure to the thread clamping portion 82. The plug arm 872 and the second spring 833 jointly apply pressure to the thread clamping portion 82, which can make the thread clamping portion 82 tighten the sewing thread 15.

[0118] like Figure 1-Figure 7 As shown, the push rod portion 87 is sleeved on the output shaft 853, and an adjusting nut 2 873 is provided on the outer side of the push rod portion 87, which is fixedly mounted on the output shaft 853; the adjusting nut 2 873 is used to limit the position of the push rod portion 87 on the output shaft 853.

[0119] When the electromagnet 81 is energized, the adjusting nut 873 moves along with the output shaft 853 and can drive the connecting sleeve 871 to move together, thereby ensuring the stability of the action execution.

[0120] In a preferred embodiment, the thread clamping portion 82 is a rotating thread clamping disc; the second spring 833 and the push rod 87 are used to provide rotational resistance to the thread clamping disc. Alternatively, in another preferred embodiment, the thread clamping portion 82 is composed of two thread clamping plates; the two thread clamping plates cooperate with each other to clamp the sewing thread; the second spring 833 and the push rod 87 are used to generate the clamping force of the two thread clamping plates.

[0121] like Figure 1-Figure 7 As shown, the bearing member 84 is fixed to the housing of the electromagnet 81 as a whole, or the bearing member 84 is formed as a whole with the electromagnet housing 811 of the electromagnet 81.

[0122] The sleeve portion 89 is formed with a step portion 893, and the step portion 893 forms a wide diameter section 894 and a narrow diameter section 895 in the sleeve portion 89, wherein the wide diameter section 894 is located at the positioning end 891 of the sleeve portion 89, and the narrow diameter section 895 is located at the loading end of the sleeve portion 89, and the guide column 840 is movably mounted on the narrow diameter section 895.

[0123] The guide post 840 is movably mounted on the narrow diameter section 895. Due to the provision of the first step 893, the travel of the guide post 840 on the sleeve portion 89 is limited, thereby limiting the position of the adjustment knob 831 mounted on the outside of the guide post 840, thereby controlling the maximum deformation of the second spring 833, and thus controlling the maximum pressure exerted by the second spring 833 on the clamping portion 82.

[0124] The electromagnet 81 includes an electromagnet housing 811 , a fixed coil 818 and an iron core. The iron core is inserted into the fixed coil 818 . The fixed coil 818 is used to generate a magnetic field.

[0125] A magnet cover 812 is provided at the end of the electromagnet housing 811, and the magnet cover 812 is used to seal the electromagnet housing 811, so that a relatively closed space can be formed inside the electromagnet 81. The electromagnet housing 811 is formed with a step portion 2 819. The magnet cover 812 can rest on the step portion 2 819, so that the magnet cover 812 does not penetrate into the interior of the electromagnet housing 811. A gasket 823 is provided between the clamping piece 1 821 and the magnet cover 812 to prevent the clamping piece 1 821 from being repeatedly squeezed toward the electromagnet 81 under long-term use, and eventually the clamping piece 1 821 is deformed, affecting the effect of clamping the sewing thread.

[0126] The iron core includes a moving iron core 85 and a static iron core 86 , and the static iron core 86 is disposed in the electromagnet housing 811 .

[0127] The electromagnet housing 811 is formed with a protruding sleeve portion 89, the wire clamping portion 82 is sleeved on the outside of the sleeve portion 89, and the movable iron core 85 is inserted into the sleeve portion 89. Through the cooperation of the sleeve portion 89 and the static iron core 86, the movable iron core 85 can be fixed on the axis position of the electromagnet 81, which facilitates the determination of the moving path of the movable iron core 85 and increases the stability of the operation of the electromagnet 81.

[0128] The portion of the movable iron core 85 extending outside the electromagnet 81 forms an output shaft 853 .

[0129] One end of the static iron core 86 is convexly formed into a convex ring portion 863 , and the electromagnet housing 811 is formed with a limiting hole 817 . The contour of the limiting hole 817 matches the convex ring portion 863 , so that the convex ring portion 863 can pass through the limiting hole 817 .

[0130] The other end of the moving iron core 85 is inserted into the static iron core 86 .

[0131] A limiting cavity 813 is formed between the magnet cover plate 812 and the static iron core 86, and a limiting portion 851 is formed on the moving iron core 85. The limiting portion 851 is movably arranged in the limiting cavity 813. A shock-absorbing pad 816 is also provided in the limiting cavity 813, which can reduce the impact generated by the limiting portion 851 when the moving iron core 85 moves, thereby extending the service life of the electromagnet 81.

[0132] A bearing groove 814 is formed in the sleeve portion 89, and a bearing 815 is disposed in the bearing groove 814. One end of the movable iron core 85 passes through the bearing groove 814, and the bearing 815 is sleeved on the outer side of the movable iron core 85.

[0133] The static iron core 86 is formed with a second bearing groove 861, and a second bearing 862 is disposed in the second bearing groove 861; the other end of the moving iron core 85 passes through the second bearing groove 861, and the second bearing 862 is disposed on the outside of the moving iron core 85;

[0134] The cooperation between bearing 1 815 and bearing 2 862 secures the position of movable iron core 85, maintaining it coaxially with electromagnet housing 811. This improves the stability of auxiliary clamp 8 during operation and further determines the position of each component. A locking portion 852 is formed on movable iron core 85. The position of locking portion 852 corresponds to that of push rod portion 87. The position of fixing hole 874 corresponds to that of locking portion 852. After passing through fixing hole 874, fixing screw 875 enters locking portion 852, integrally connecting adjusting nut 2 873 to movable iron core 85.

[0135] As a preferred embodiment, a locking portion 852 can be formed on the moving iron core 85. When the bearing member 84 is sleeved on the moving iron core 85, the position of the fixing hole 874 is aligned with the position of the locking portion 852, so that the fixing screw 875 can enter the locking portion 852 after passing through the fixing hole 874, thereby connecting the bearing member 84 and the moving iron core 85 into one, which can better ensure that the adjusting nut 2 873 and the moving iron core 85 maintain synchronous movement.

[0136] like Figures 1-11 As shown, the main clamp 11 is an electric clamp, and the main clamp 11 includes:

[0137] The driving motor 3 can directly or indirectly drive the rotating shaft 31 to rotate.

[0138] The winding device 2 is mounted on a rotating shaft 31 and is provided with a winding area 27 for winding the sewing thread 15. When the rotating shaft 31 rotates, the winding device 2 rotates with the rotating shaft 31, driving the sewing thread 15 wound on the winding device 2 to rotate together. After the sewing thread 15 rotates through a certain angle, it detaches from the winding device 2, thereby feeding the sewing thread to the sewing needle 12. When the winding device 2 rotates in a first direction, it feeds the sewing thread 15 to the sewing needle 12. At this time, the sewing thread 15 is relatively loose, and the degree of looseness can be adjusted by the rotating shaft 31 to better match the sewing action of the sewing needle 12. When the winding device 2 rotates in a second direction, the winding device 2 tightens the sewing thread 15 between the sewing needle 12 and the winding device 2. The first and second directions are opposite to each other. By rotating in two different directions, the tension or loosening of the sewing thread 15 can be controlled by the main thread clamp 11.

[0139] In this technical solution, the purpose of controlling the tension of the sewing thread 15 is achieved by controlling the rotation speed of the winding device 2 and thus controlling the amount of sewing thread 15 fed. Since the rotating shaft 31 is connected to the drive motor 3, the drive motor 3 can also actively drive the winding device 2 to rotate, achieving a stable thread feeding action. When facing the situation of sewing fabrics of different thicknesses and different stitch lengths, the drive motor 3 can achieve more precise and detailed control of thread feeding, so that the sewing thread 15 can adjust the tension of the sewing thread 15 according to the current operation of the sewing machine while ensuring sufficient thread feeding, so as to cooperate with the needle 12 to perform sewing actions, thereby improving the quality of the sewn product.

[0140] The winding device 2 is rotatably mounted on the rotating shaft 31, and a damping mechanism is provided between the winding device 2 and the rotating shaft 31. When relative rotation occurs between the winding device 2 and the rotating shaft 31, the damping mechanism can adjust and set the rotation resistance of the winding device 2 in the first direction and the second direction.

[0141] Since the main clamp 11 in the present technical solution is provided with a driving motor 3 to control the winding device 2, it can more flexibly and accurately control the tension of the sewing thread 15 when facing fabrics of different thicknesses, different stitch lengths, etc., and it is therefore also easy to upgrade and modify different types of sewing machine housings 1 currently on the market.

[0142] The sewing machine housing 1 is also provided with a secondary thread tensioner 8 and a thread take-up lever 14. The sewing thread 15 passes through the secondary thread tensioner 8, the primary thread tensioner 11, the thread take-up hook 13, and the thread take-up lever 14 in sequence before being fed into the needle 12. The secondary thread tensioner 8 is the first thread tensioner fed to the needle 12 by the sewing machine. Its main function is to adjust the length of the thread end remaining on the needle 12 after thread trimming. The tighter the secondary thread tensioner 8 is, the tighter the sewing thread 15 is stretched during thread trimming, the more the thread retracts after trimming, and the shorter the thread end remaining on the needle 12.

[0143] Furthermore, the thread take-up hook 13 is an optional component and is not provided on the sewing machine housing 1 .

[0144] like Figures 1-11 As shown, the winding area 27 is an annular area provided on the surface of the winding device 2. The vertical cross-section of the annular area is an inwardly concave U-shape or V-shape. When the sewing thread 15 is wound in the winding area, due to the limitation of its own tension, the sewing thread 15 will adhere to the bottom of the winding area 27. The U-shape or V-shape can better limit the trajectory of the sewing thread 15 and prevent the position of the sewing thread 15 from deviating, thereby making the thread feeding action more stable and ensuring the thread feeding amount.

[0145] like Figures 1-13 As shown, the winding device 2 is in the shape of a disk, and a winding area 27 is provided on the circumferential surface of the disk. The winding device 2 includes two turntables 21, and the turntable 21 is in the shape of a boss; the middle part of the turntable 21 is a base portion 22, and the outside of the turntable is a circular ring portion 23. A plurality of inclined connecting ribs 25 are provided between the base portion 22 and the circular ring portion 23, and a slot 24 is formed between two adjacent connecting ribs 25. A circular ring portion 23 is provided on the outside of the base portion 22, and a plurality of slots 24 are opened on the circular ring portion 23, and the slots 24 are kept at uniform intervals. Connecting ribs 25 are formed between the slots 24, and the connecting ribs 25 are used to connect the base portion 22 and the circular ring portion 23. After the two base portions 22 are abutted together, they can maintain synchronous rotation, and the two circular ring portions are provided on the outside of the base portion 22.

[0146] As a preferred technical solution, the winding device 2 is integrally formed, and the two base parts 22 are welded or bonded together.

[0147] As another preferred technical solution, the two base parts 22 can also be split and snap-connected into one.

[0148] This ensures that the two turntables 21 rotate synchronously, allowing the winding device 2 to more accurately loosen or tighten the sewing thread 15. The integrally formed winding device 2 also facilitates installation. The connecting ribs 25 of the two turntables 21 form an angle, which circumscribes the winding area 27, with the base forming the bottom of the winding area 27. The center of the base 22 is mounted on a rotating shaft 31 and is rotatable.

[0149] In the prior art, two thread clamps are usually used to clamp the sewing thread 15. Since friction is generated between the two thread clamps, the movement of the sewing thread 15 is hindered. When the two thread clamps are separated, there is no clamping force. At this time, the sewing thread 15 is not clamped and is in a relatively relaxed state, allowing for rapid thread feeding. When the two thread clamps are brought closer together, the two thread clamps clamp the sewing thread 15 in the middle, putting the sewing thread 15 in a relatively taut state. By increasing the pressure on the thread clamps, the tension of the sewing thread 15 can be adjusted. However, when faced with different fabrics or different sewing machines, parameters such as fabric thickness and stitch length will change. It is difficult for the thread clamps currently on the market to make more precise thread feeding or tensioning actions for these situations.

[0150] One side of the turntable 21 is convexly formed into a base portion 22, giving the turntable 21 a disc shape. The base portions 22 of the two turntables 21 abut against each other at one end to form the winding device 2. When the two turntables 21 are connected to form the winding device 2, the two base portions 22 abut against each other to form a winding area 27 for winding the sewing thread 15. This helps prevent the sewing thread 15 from moving easily after being wound on the winding device 2.

[0151] As the winding device 2 rotates, the amount of sewing thread 15 fed is controlled, thereby achieving the purpose of controlling the tension of the sewing thread 15. Since the rotating shaft 31 is connected to the drive motor 3, the drive motor 3 can actively drive the winding device 2 to rotate and stably feed the thread. In the case of fabrics of different thicknesses and different stitch lengths, the drive motor 3 can control the thread feeding more accurately and meticulously, so that the sewing thread 15 can adjust the tension of the sewing thread 15 according to the current operation of the sewing machine while ensuring sufficient thread feeding, so as to facilitate the sewing action and improve the quality of the sewn product. A damping mechanism is abutted against the outer side of the base portion 22, and the damping mechanism is fixed to the rotating shaft 31. The damping mechanism can adjust the pressure applied to the winding device, thereby adjusting the resistance of the winding device 2.

[0152] like Figures 1-11 As shown, the damping mechanism includes a clamping component 5, a spring 63 and an adjusting nut 4.

[0153] The clamping component 5 includes a first clamping portion 7 and a second clamping portion 6, wherein the first clamping portion 7 can be a retaining ring structure on the rotating shaft, which only needs to achieve abutment against the base portion 22. There is no need for the first clamping portion 7 to apply pressure to the winding device 2, but resistance is applied to the winding device 2 through the second clamping portion 6.

[0154] In this embodiment, the second clamping portion 6 is a combination of a pressing plate 61 , a wire felt 64 and a retaining ring 62 .

[0155] The first clamping portion 7 is mounted on the rotating shaft 31 and abuts against one of the base portions 22. The second clamping portion 6 is mounted on the rotating shaft and presses against the other base portion 22 from the other side. One end of a spring 1 63 abuts against the pressure plate 61 of the second clamping portion 6, while the other end of the spring 1 63 abuts against the adjustment nut 1 4.

[0156] The adjusting nut 4 is rotatably mounted on the rotating shaft 31 and is connected to the rotating shaft thread. The position of the adjusting nut 4 on the rotating shaft 31 can be changed by cooperating with the rotating shaft thread. When the position of the adjusting nut 4 changes, the spring 63 will be deformed accordingly, thereby increasing the pressure exerted by the spring 63 on the winding device 2.

[0157] like Figures 1-11 As shown, the second clamping portion 6 includes a retaining ring 62. A fixing groove 1 32 is provided in the middle of the rotating shaft 31. The fixing groove 1 32 extends along the length of the rotating shaft 31 from the end where the adjusting nut 1 4 is mounted inward to the base portion 22. Both the retaining ring 62 and the pressure plate 61 are formed with a through hole 1 51. A crossbeam 52 is formed within the through hole 1 51. The dimensions of the crossbeam 52 match the fixing groove 1 32, allowing the crossbeam 52 to slide within the fixing groove 1 32.

[0158] The pressing plate 61 is pressed tightly against the base portion 22 ; a wire felt 64 is further provided between the pressing plate 61 and the base portion 22 .

[0159] like Figures 1-11 As shown, the first clamping portion 7 includes a washer 71 , which is fixed on the rotating shaft 31 and is used to abut against the base portion 22 ; a wire felt 64 is provided between the washer 71 and the base portion 22 .

[0160] A wire felt 64 is provided between the washer 71 and the winding device 2, and between the pressure plate 61 and the winding device 2. The wire felt 64 is used to evenly distribute pressure on the base portion 22. When the winding device 2 rotates, the uniform pressure applied to the winding device 2 is converted into resistance, preventing the winding device 2 from rotating and changing the speed at which the winding device 2 feeds the wire. By increasing or decreasing pressure on the wire felt 64, the resistance applied to the winding device 2 changes, thereby adjusting the wire feeding of the winding device 2.

[0161] like Figures 1-14 As shown, the middle of the connecting rib 25 is formed into a bent portion 26 , and the bent portion 26 protrudes from the base portion 22 .

[0162] The middle of the connecting rib 25 is formed into a bent portion 26. When the turntables 21 are connected into one, the connecting ribs 25 are staggered so that the bent portion 26 can correspond to the position of the empty slot 24 on the other turntable 21, so that the bent portion 26 of one turntable 21 can be embedded in the position of the empty slot 24 on the other turntable 21.

[0163] like Figures 1-9 As shown, the bending portion 26 divides the connecting rib 25 into a first oblique extending portion 251 and a second oblique extending portion 252. The first oblique extending portion 251 is located outside the second oblique extending portion 252, that is, the first oblique extending portion 251 is connected to the annular portion 23, and the second oblique extending portion 252 is connected to the base portion 22.

[0164] Two adjacent first oblique extensions 251 cooperate to form a U-shaped or V-shaped winding area 27 for winding the sewing thread 15. The sewing thread 15 contacts the adjacent first oblique extensions 251 and is fixed in the winding area 27. A certain gap 28 is provided between the two adjacent first oblique extensions 251.

[0165] Because the bends 26 intersect, when the sewing thread 15 is inserted inward along the first obliquely extending portion 251, the actual amount of thread winding between the intersection of two adjacent first obliquely extending portions and the bend 26 does not necessarily decrease (the diameter of a standard circular ring is reduced when it is transformed into a repeatedly bent circular ring, but the circumferential length does not necessarily decrease). Therefore, the bends 26 can prevent the sewing thread 15 from further shrinking inward. The more the sewing thread 15 shrinks inward, the greater the friction it encounters, making it easier to transport the sewing thread 15 to cope with different working scenarios.

[0166] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sewing machine capable of adjusting the tension of a sewing thread, comprising a sewing machine housing (1) and a machine needle (12), characterized in that: The sewing machine housing (1) is provided with a thread feeding mechanism, which includes a main thread clamp (11), an auxiliary thread clamp (8), a thread take-up hook (13) and a thread take-up rod (14); the sewing thread (15) passes through the auxiliary thread clamp (8), the main thread clamp (11), the thread take-up hook (13) and the thread take-up rod (14) in sequence, and then is input into the machine needle (12); the auxiliary thread clamp (8) includes an electromagnet (81) serving as a power source for the secondary clamp (8); A thread clamping portion (82) for clamping the sewing thread (15); an adjusting portion (83) capable of adjusting the force applied by the thread clamping portion (82) to the sewing thread (15); A load-bearing member (84) including a sleeve portion (89); One end of the sleeve portion (89) is a loading end (892), and the other end is a positioning end (891); the wire clamping portion (82) is inserted into the sleeve portion (89) from the loading end (892); The adjusting portion (83) includes an adjusting knob (831) and a second spring (833); the adjusting knob (831) is screw-mounted on the bearing member (84) and is close to the insertion end (892) of the sleeve portion (89); one end of the second spring (833) abuts against the wire clamping portion (82), and the other end abuts against the adjusting knob (831); the adjusting knob (831) squeezes the second spring (833), so that the second spring (833) pushes the wire clamping portion (82); The output shaft (853) of the electromagnet (81) passes through the sleeve portion (89) and extends out of the insertion end (892); a push rod portion (87) is mounted on the output shaft (853), the push rod portion (87) faces the wire clamping portion (82), and a second through hole (845) or a second empty slot (841) for the push rod portion (87) to pass through is provided on the bearing member (84); When the electromagnet (81) is energized, the output shaft (853) drives the push rod portion (87) to squeeze the wire clamping portion (82); The bearing member (84) further comprises: A guide post (840) mounted on the insertion end (892) of the sleeve portion (89); The surface of the guide column (840) is threadedly engaged with the adjusting knob (831); The second through hole (845) is provided in the middle of the guide post (840), or the second empty groove (841) is provided on the surface of the guide post (840); The adjusting knob (831) is formed with a second fixing groove (832); one end of the second spring (833) is arranged in the second fixing groove (832), and the other end of the second spring (833) rests on the wire clamping portion (82).

2. A sewing machine with adjustable sewing thread tension according to claim 1, characterized in that: The push rod portion (87) includes a connecting sleeve (871) and a plurality of plug-in arms (872); the plug-in arms (872) are arranged on the peripheral side of the connecting sleeve (871), and the plug-in arms (872) face the wire clamping portion (82); The guide column (840) is formed with the second empty slot (841) that matches the plug-in arm (872), so that the plug-in arm (872) can extend into the second empty slot (841); The push rod portion (87) is sleeved on the output shaft (853), and an adjusting nut (873) is provided on the outside of the push rod portion (87) and is fixedly mounted on the output shaft (853); the adjusting nut (873) is used to limit the position of the push rod portion (87) on the output shaft (853).

3. A sewing machine with adjustable sewing thread tension according to claim 2, characterized in that: The guide column (840) includes a middle seat body (842) and a plurality of arc-shaped leaves (843) arranged on the circumference of the middle seat body (842); the second empty slot (841) is formed between two adjacent arc-shaped leaves (843), and the surface of the arc-shaped leaves (843) is provided with external threads; One end of the arc-shaped leaf (843) extends to the outside of the middle seat (842) and forms a concave area (844); the connecting sleeve (871) of the top rod portion (87) is integrally placed in the concave area (844); the plug-in arm (872) extends from the concave area (844) into the corresponding empty slot 2 (841); The wire clamping portion (82) is a rotary wire clamping disc; the second spring (833) and the push rod portion (87) are used to form the rotation resistance of the wire clamping disc; or, The thread clamping portion (82) is composed of two thread clamping pieces; the two thread clamping pieces cooperate with each other and clamp the sewing thread (15); the second spring (833) and the top rod portion (87) are used to form the clamping force of the two thread clamping pieces; The bearing member (84) is fixed to the housing of the electromagnet (81) as a whole, or the bearing member (84) is formed as a whole with the electromagnet housing (811) of the electromagnet (81).

4. A sewing machine with adjustable sewing thread tension according to claim 1, characterized in that: The main thread clamp (11) is an electric thread clamp, and the main thread clamp (11) comprises: A drive motor (3) having a rotating shaft (31) formed thereon, the drive motor (3) directly or indirectly driving the rotating shaft (31) to rotate, the drive motor (3) being arranged in the sewing machine housing (1); A winding device (2), wherein the winding device (2) is provided with a winding area (27), and the winding area (27) is used for winding the sewing thread (15); When the rotating shaft (31) rotates, the winding device (2) rotates along with the rotating shaft (31); When the winding device (2) rotates in a first direction, the winding device (2) drives the sewing thread (15) to supply the sewing thread to the needle (12); When the winding device (2) rotates in the second direction, the winding device (2) tightens the sewing thread (15) between the needle (12) and the winding device (2); The first direction and the second direction are opposite to each other; The winding device (2) is rotatably mounted on the rotating shaft (31), and a damping mechanism is provided between the winding device (2) and the rotating shaft (31); when relative rotation occurs between the winding device (2) and the rotating shaft (31), the damping mechanism sets the rotational resistance of the winding device (2) in a first direction and a second direction.

5. A sewing machine with adjustable sewing thread tension according to claim 4, characterized in that: The winding area (27) is an annular area provided on the surface of the winding device (2), and the vertical cross-section of the annular area is an inwardly concave U-shape or V-shape.

6. A sewing machine with adjustable sewing thread tension according to claim 4, characterized in that: The winding device (2) is in the shape of a disk, and the winding area (27) is provided on the circumferential surface of the disk; The winding device (2) comprises two turntables (21), each turntable (21) being in the shape of a boss; the middle portion of the turntable (21) is a base portion (22), the outer portion of the turntable (21) is a circular ring portion (23), a plurality of inclined connecting ribs (25) are provided between the base portion (22) and the circular ring portion (23), and an empty slot (24) is formed between two adjacent connecting ribs (25); The two base parts (22) are close together and rotate synchronously, and the two annular parts (23) are arranged on the outside; The connecting ribs (25) of the two rotating disks (21) cooperate to form an angle, and the angle is circled to form the winding area (27); The center of the base portion (22) is sleeved on the rotating shaft (31) and is rotatable; The damping mechanism is abutted against the outer side of the base portion (22), and the damping mechanism is fixed on the rotating shaft (31).

7. A sewing machine with adjustable sewing thread tension according to claim 6, characterized in that: The damping mechanism comprises a clamping component (5), a spring (63) and an adjusting nut (4); The clamping component (5) includes a first clamping portion (7) and a second clamping portion (6); the first clamping portion (7) is arranged on the rotating shaft (31) and abuts against one of the base portions (22); the second clamping portion (6) is arranged on the rotating shaft (31) and squeezes the other base portion (22) from the other side; one end of the spring (63) abuts against the second clamping portion (6), and the other end of the spring (63) abuts against the adjusting nut (4); the adjusting nut (4) is rotatably mounted on the rotating shaft (31) and is threadedly connected to the rotating shaft (31), and the pressure applied to the spring (63) can be changed by changing the position of the adjusting nut (4) on the rotating shaft (31).

8. The sewing machine with adjustable sewing thread tension according to claim 7, characterized in that: The second clamping portion (6) includes a retaining ring (62); A second fixing groove (832) is provided in the middle of the rotating shaft (31); the second fixing groove (832) extends inwardly from one end where the adjusting nut (4) is installed to the base portion (22) along the length direction of the rotating shaft (31); The retaining ring (62) and the pressure plate (61) are both formed with a through hole (51), a crossbeam (52) is formed in the through hole (51), and the size of the crossbeam (52) matches the second fixing groove (832), so that the crossbeam (52) can slide in the second fixing groove (832); The pressing plate (61) is pressed tightly against the base portion (22); A wire felt (64) is provided between the pressing plate (61) and the base portion (22).

9. The sewing machine with adjustable sewing thread tension according to claim 6, characterized in that: The middle of the connecting rib (25) is formed into a bent portion (26), and the bent portion (26) protrudes from the base portion (22); When the two turntables (21) are connected into one body, the connecting arms of the two turntables (21) are staggered so that the bent portion (26) of one of the turntables (21) can be embedded in the position of the empty slot (24) on the other turntable (21); The bending portion (26) divides the connecting rib (25) into a first oblique extension portion (251) and a second oblique extension portion (252); the first oblique extension portion (251) is located outside the second oblique extension portion (252); Two adjacent first obliquely extending portions (251) cooperate to form the V-shaped winding area (27); A certain gap (28) is provided between two adjacent first obliquely extending portions (251).

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