WO2018126331A1

WO2018126331A1 - Sewing machine having improved automatic thread cutting mechanism

Info

Publication number: WO2018126331A1
Application number: PCT/CN2017/000008
Authority: WO
Inventors: 肖修锋
Original assignee: 肖修锋
Priority date: 2017-01-03
Filing date: 2017-01-03
Publication date: 2018-07-12

Abstract

A sewing machine having an improved automatic thread cutting mechanism. An outward-facing side of a stitching arm is determined as a left side. A rotary hook transmission shaft (5) and a cutting blade drive shaft (2) are rotatably installed in an inner portion of the stitching arm. The cutting blade drive shaft (2) is sleeved over the rotary hook transmission shaft (5). A rotary hook base for accommodating a rotary hook is provided at an upper portion of the rotary hook transmission shaft (5). An upper plate of a fixed stitching cover (3) is provided with a needle plate (33). A fixed blade (4) is fixed to a lower face of the needle plate (33). A cutting blade movement space is provided below the needle plate (33), and is located between a side wall of the fixed stitching cover (3) and the cutting blade drive shaft (2). A sweep cutting blade (1) is fixed to the cutting blade drive shaft (2), and is provided at the cutting blade movement space. A blade member (11) is provided at an upper portion of the sweep cutting blade (1). In a thread cutting process, the sweep cutting blade (1) performs one to-and-fro movement in the cutting blade movement space below the fixed stitching cover (3). The blade member (11) of the sweep cutting blade (1) cooperates with the fixed blade (4) to perform a cutting operation. The present invention enables a simple structure, and a compact size of the stitching arm, thus providing superior flexibility and convenience during a sewing process. In addition, the sweep cutting blade (1) has high structural strength, provides a large cutting force, and enables smooth, stable, and reliable thread cutting, thus facilitating thread cutting operation.

Description

Sewing machine for improving automatic thread cutting mechanism

Technical field

The invention relates to the technical field of industrial sewing machines, and in particular to a sewing machine for improving an automatic thread cutting mechanism.

Background technique

The industrial sewing machine (commonly known as the sewing machine) is provided with a sewing arm protruding above the panel, and the upper part of the sewing arm is provided with a rotary hook seat and a thread cutting device, such as the patent number "ZL200910048135.4", and the patent name is "one. According to the Chinese invention patent of the automatic thread trimming device for a sewing machine, a cutter and a fixed blade are mounted above the rotary bobbin, and the fixed blade is mounted on the left side of the cutter drive shaft, and the cutter is fixed to the cutter by the bracket The right side of the drive shaft drives the cutter to rotate by the cutter drive shaft, so that the cutter can be cut and matched with the fixed blade to realize the trimming function. The structure design of the prior art cutter is unreasonable, and the phenomenon that the wire cannot be cut off often occurs, and the trimming action is not stable and reliable. In addition, since the cutter and the bracket protrude from the right side of the cutter drive shaft, in order to accommodate the cutter and the bracket in the sewing arm, the right side of the sewing arm needs to be enlarged, so the overall volume of the sewing arm is biased. Big. When sewing the toe cap, the toe cap needs to be placed on the sewing arm, and the inner space of the toe cap and the like is small, the rotating space of the toe cap is small, the toe cap is very difficult to be sewn, and often interferes with the sagging arm and Blocking, affecting the quality of sewing and reducing the processing efficiency, it is necessary to improve.

Summary of the invention

In view of the deficiencies of the prior art, the object of the present invention is to provide a sewing machine with improved automatic thread cutting mechanism, which has a simple structure, a smaller sewing arm, and is more flexible and convenient for sewing processing.

In view of the deficiencies of the prior art, another object of the present invention is to provide a sewing machine with improved automatic thread cutting mechanism. The sweeping cutter has higher structural strength, greater shear force, and smoother and more stable thread cutting action. Reliable, the thread trimming is more versatile.

In order to achieve the above object, the technical solution adopted by the present invention is.

A sewing machine for improving an automatic thread cutting mechanism comprises a sewing arm protruding above a needle car panel, a fixed sewing cover is fixed on a left upper part of the sewing arm, and a sweeping cutter is arranged in the sewing arm, the vehicle is provided The outward side of the arm is set to the left side, and the inside of the sewing arm is respectively rotatably mounted with a rotary drive shaft and a cutter drive shaft. The cutter drive shaft is set on the outer edge of the rotary drive shaft, and the rotary drive shaft The top of the top is provided with a rotary hook seat for placing the rotary hook, and the top panel of the fixed sewing cover is a needle plate, and the bottom surface of the needle plate is fixed with a fixed blade; the movable space of the cutter is arranged below the needle plate, and the movable space of the cutter is located Between the side wall of the fixed sewing cover and the cutter drive shaft; the sweeping cutter is fixed to the cutter drive shaft, the sweeping cutter is disposed in the cutter movable space, and the upper portion of the sweeping cutter is provided with the cutter body During the trimming process, the sweeping cutter moves back and forth in the movable space of the cutter below the fixed sewing cover, and the cutter body of the sweeping cutter is cut-fitted with the fixed blade.

In a further technical solution, the sewing machine is provided with a rotary hook drive mechanism and a driving mechanism for driving the cutter drive shaft at a fixed angle reciprocating rotary cutter, and the rotary hook drive mechanism is connected to the rotary hook drive shaft, and the cutter drive mechanism Connecting the cutter drive shaft, the cutter drive shaft drives the sweeping cutter to reciprocate once along the arc path in the movable space of the cutter during a trimming process; the bottom surface of the needle plate has an arc groove. The fixed blade is fixed in the arc groove, and the fixed blade is located at one end of the arc groove. In the initial state, the fixed blade and the cutter body are respectively located at two ends of the arc groove, and the cutter body is in the arc groove when the wire is trimmed Move along the curved path toward the stationary blade and shear fit with the stationary blade.

In a further technical solution, the needle plate is provided with a lower pinhole, the lower pinhole penetrating downwardly through the arcuate groove, and the lower pinhole is located at a middle position of the arcuate groove; in the initial state, the blade body and Solid The fixed blades are respectively located at two sides below the lower pinhole; when the blade body and the fixed blade are shear-fitted, the blade body and the fixed blade are overlapped in the arc groove; the right upper part of the sewing arm is coupled with a turnable The movable sewing cover opened or removed, the fixed sewing cover and the movable sewing cover are assembled to cover the upper part of the sewing arm; the cutter driving shaft is disposed at a position right below the fixed sewing cover.

In a further technical solution, the sweeping cutter comprises a fixed portion, a support plate and the cutter body, and the top of the fixed portion is bent upward to extend out of the support plate, and the upper end portion of the support plate faces the inner side. The direction is laterally bent out of the cutter body;

The cutter drive shaft is fixed with a jacket, and the fixing portion is fixed to the jacket. When the cutter drive shaft rotates back and forth, the cutter body reciprocates in an annular region of the outer edge of the cutter drive shaft.

In a further technical solution, one end of the cutter body facing the fixed blade is a front end portion, and a front end portion of the cutter body is formed with an inclined or curved oblique hook line portion, and a top surface of the cutter body is provided with a crimping groove and a pressing line. The outer end portion of the groove extends outwardly and penetrates to the oblique hook line portion for hooking the line to be cut during the process of sweeping the fixed blade, and the inner end portion of the pressure line groove is provided with a trimming matching hole The trimming fit hole penetrates the cutter body, and the top edge of the trimming fit hole is disposed as a cutting edge, and the fixed blade is formed with a shearing portion, a shearing portion and a shearing portion toward a bottom edge of one side of the cutter body Cutting edge cut fit.

In a further technical solution, a crimping piece is disposed in the arcuate groove, and the crimping piece is fixed under the fixed blade, and a pressing piece elastic piece is bent downward in the middle of the pressing piece, and the cutting body and the fixed body are fixed. When the blade is sheared, the end portion of the pressing elastic piece elastically abuts against the crimping groove for pressing the wire to be cut against the groove bottom of the crimping groove.

In a further aspect, the side of the oblique hook line portion facing the cutter drive shaft is an inner portion, the side connected to the support plate is an outer portion, and the inner portion of the oblique hook line portion is formed as A pointed portion, an outer portion of the oblique hook line portion is formed with an arc-shaped retaining wire portion, and the tip portion protrudes forward.

In a further technical solution, the upper and lower ends of the curved retaining wire portion respectively penetrate the cutter body On the upper and lower sides, the first side of the curved retaining line portion is tangent to the oblique hook line portion, and the second side is tangent to the support plate; the shearing portion protrudes at the bottom edge of the cutter body, and the shearing portion faces the knife The end surface of the body is a vertical plane, and the bottom surface of the shearing portion is a curved surface.

In a further technical solution, the support plate is a curved panel, and the curved panel has a curved concave surface, the curved concave surface of the support plate faces the cutter drive shaft, and the cutter body is located at the top of the curved concave surface of the support plate.

In a further technical solution, a side of the support plate facing away from the fixed blade is provided with a wing plate, and the wing plate is an arc-shaped panel extending outward from the rear end portion of the blade body, and the top of the wing plate The top surface of the blade is flush with the top surface of the blade body; the inner surface of the wing plate is formed with a concave and convex portion, and the thickness of the lower portion of the extension plate is greater than the thickness of the upper portion.

Compared with the prior art, the invention has the advantages that the structure of the invention is simple, the volume of the sewing arm is smaller, and the sewing process is more flexible and convenient.

In addition, the sweeping cutter of the present invention has higher structural strength, greater shearing force, smoother, more stable and reliable thread cutting action, and more stringent trimming.

DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

Figure 1 is a schematic view of the structure of the present invention.

Figure 2 is a schematic view showing the structure of another aspect of the present invention.

Fig. 3 is a schematic view showing the structure of the sweeping cutter and the fixed blade of the present invention in an initial state.

Fig. 4 is a schematic view showing the structure of the sweeping cutter of the present invention when it is swept toward the fixed blade.

Fig. 5 is a schematic view showing the structure of a sweeping cutter of the present invention.

Figure 6 is a plan view of a sweeping cutter of the present invention.

In the picture:

1. Sweeping cutter 10, cutting edge 11, cutter body 12, fixing portion 13, support plate 14, installation The hole 15, the oblique hook line portion 16, the crimping groove 17, the trimming fitting hole 18, the curved retaining wire portion 19, and the flap.

2. The cutter drive shaft 21 and the jacket.

3. Fix the sewing cover 31, the lower pinhole 32, the curved groove 33, and the needle plate.

4. The fixed blade 41 and the cutting portion.

5. Rotary shuttle drive shaft.

6, pressure line 61, pressure line shrapnel.

detailed description

The following description is only a preferred embodiment of the invention and is not intended to limit the scope of the invention.

A sewing machine for improving an automatic thread cutting mechanism, as shown in Figs. 1 to 6, includes a sewing arm protruding from a needle car panel, and a sweeping cutter 1 is disposed in the sewing arm, and the upper left side of the sewing arm A fixed sewing cover 3 is fixed to the fixed part, and the outward side of the sewing arm is set to the left side, and the inside of the sewing arm is respectively rotatably mounted with the rotary drive shaft 5 and the cutter drive shaft 2, and the cutter drive shaft 2 is set. At the outer edge of the rotary drive shaft 5, the cutter drive shaft 2 is mounted coaxially with the rotary shuttle drive shaft 5, and the cutter drive shaft 2 and the shuttle drive shaft 5 do not interfere with each other, and each rotates independently. The sewing arm is fixed in a plurality of bearing seats, and the cutter driving shaft 2 and the hook driving shaft 5 are respectively rotatably mounted on the corresponding bearing seats, and the outer edge of the cutter driving shaft 2 is further mounted with a fixed shaft and/or a protective sleeve. The top of the rotary drive shaft 5 is provided with a rotary hook seat for placing the rotary hook, and the right upper upper portion of the sewing arm is fastened with a movable sewing cover which can be opened or removed, and the fixed sewing cover 3 and the movable sewing cover are left and right. The upper part of the sewing arm is assembled and assembled; the cutter driving shaft 2 is disposed at a position right below the fixed sewing cover 3. In order to better demonstrate the innovative structure of the present invention, the slat arm, the hook support and the movable sewn cover are not shown.

The sewing machine is provided with a rotary hook drive mechanism and a driving mechanism for driving the cutter drive shaft 2 at a fixed angle reciprocating rotary cutter, the rotary hook drive mechanism is connected with the rotary drive shaft 5, and the cutter drive mechanism is connected to the cutter drive shaft 2, and the cutter drive The mechanism connects the lower end of the cutter drive shaft 2. The cutter drive mechanism can be electromagnetically driven The mechanism or the motor drive mechanism may also be a drive mechanism that is driven and connected by the transmission mechanism of the sewing machine, as long as the function of driving the cutter drive shaft 2 to rotate at a fixed angle and reciprocating once during the trimming is realized, that is, in one trimming process The cutter drive shaft 2 drives the sweeping cutter 1 to swipe back and forth along the curved path in the cutter movable space. The hook drive mechanism and the cutter drive mechanism are not shown.

Wherein, the top panel of the fixed sewing cover 3 has a needle plate 33, and the bottom surface of the needle plate 33 is fixed with a fixed blade 4; under the needle plate 33, a cutter movable space is arranged, and the movable space of the cutter is located at the fixed sewing cover 3 Between the side wall and the cutter drive shaft 2; the sweeping cutter 1 is fixed to the cutter drive shaft 2, the sweeping cutter 1 is disposed in the cutter movable space, and the upper portion of the sweeping cutter 1 is provided with the cutter body 11; in a trimming process, the sweeping cutter 1 moves back and forth once in the cutter movable space below the fixed sewing cover 3, and the cutter body 11 of the sweeping cutter 1 is shear-fitted with the fixed blade 4.

The invention changes the sweeping cutter 1 from the right side of the cutter drive shaft 2 to the left side of the cutter drive shaft 2, further reducing the volume of the sewing arm, and the head of the sewing arm is smaller in size. The toe provided on the sewing arm has more turning space, and the toe can be rotated more flexibly during sewing without being disturbed and blocked by the sewing arm, so that the quality can be sewn and the processing efficiency can be improved.

The bottom surface of the needle plate 33 defines an arcuate groove 32. The fixed blade 4 is fixed in the arcuate groove 32. The fixed blade 4 is located at one end of the arcuate groove 32. In the initial state, the fixed blade 4 and the blade body 11 are respectively located in an arc shape. At both ends of the groove 32, the cutter body 11 moves in the arcuate groove 32 along the curved path toward the fixed blade 4 and is shear-fitted with the fixed blade 4 at the time of thread trimming. The needle plate 33 is provided with a lower pinhole 31 which penetrates the arcuate groove 32 downwardly, and the lower pinhole 31 is located at a middle position of the arcuate groove 32; in the initial state, the blade body 11 and the fixed blade 4 are respectively located The two sides below the lower pinhole 31; when the blade body 11 is shear-fitted with the fixed blade 4, the blade body 11 and the fixed blade 4 are vertically overlapped in the arcuate groove 32.

The sweeping cutter 1 includes a fixed portion 12 integrally coupled to the support plate 13 and the blade body 11. The top of the fixing portion 12 is bent upward to extend out of the support plate 13, and the upper end portion of the support plate 13 is oriented inwardly The cutter body 11 is bent out; the cutter drive shaft 2 is fixed by a screw to the jacket 21, and the fixing portion 12 is fixed to the jacket 21 by screwing. When the cutter drive shaft 2 rotates back and forth, the cutter body 11 is in the cutter. The circular motion of the outer edge of the drive shaft 2 reciprocates. The volume of the entire sweeping cutter 1 is made smaller, the sweeping cutter 1 is more compact, and the sweeping cutter 1 is located in the annular region of the outer edge of the cutter drive shaft 2, following the cutter drive shaft 2 rotation. , to achieve the trimming action.

One end of the blade body 11 facing the fixed blade 4 is a front end portion, and a front end portion of the blade body 11 is formed with an inclined or curved oblique hook line portion 15. The top surface of the blade body 11 defines a crimping groove 16 and a crimping groove 16 The outer end portion extends outwardly and penetrates the oblique hook line portion 15 for hooking the line to be cut during the sweeping of the fixed blade 4, and the inner end portion of the crimping groove 16 is provided with a trimming line. With the matching hole 17, the trimming matching hole 17 penetrates the blade body 11, the top edge of the wire trimming hole 17 is provided as a cutting edge 10, and the cutting edge of the fixed blade 4 toward the side of the blade body 11 is formed with a cutting portion 41. The shearing portion 41 is shear-fitted with the cutting edge 10. The specially designed cutter body 11 has a smaller shape, a larger shear force, and can improve the stability and reliability of the trimming action, and the trimming line is more versatile.

A crimping piece 6 is disposed in the arcuate groove 32. The crimping piece 6 is fixed under the fixed blade 4. The middle part of the crimping piece 6 is bent downwardly to form a pressing wire elastic piece 61, and the cutting body 11 and the fixed blade 4 are cut and matched. The end portion of the press-line elastic piece 61 elastically abuts against the crimping groove 16 for pressing the wire to be cut on the bottom of the groove of the crimping groove 16, and pressing the wire during trimming to improve the stability of the trimming line. And can keep the thread head a certain margin.

The side of the oblique hook line portion 15 facing the cutter drive shaft 2 is an inner portion, the side connected to the support plate 13 is an outer portion, and the inner portion of the oblique hook line portion 15 is formed as a tip portion, and a diagonal hook line The outer portion of the portion 15 is formed with an arcuate retaining wire portion 18, the tip portion of which protrudes forward. The upper and lower ends of the curved retaining wire portion 18 respectively penetrate the upper and lower surfaces of the cutter body 11, the first side of the curved retaining wire portion 18 is tangent to the oblique hook line portion 15, and the second side is tangent to the support plate 13; The cut portion 41 protrudes from the bottom edge of the cutter body 11, the shearing portion 41 faces the end surface of the cutter body 11 as a vertical plane, and the bottom surface of the shearing portion 41 is a curved surface, which has an automatic sharpening function. The shearing portion 41 is kept in a sharp state for a long period of time.

The support plate 13 is an arcuate panel having an arcuate concave surface, the arcuate concave surface of the support plate 13 is directed toward the cutter drive shaft 2, and the cutter body 11 is located at the top of the arcuate concave surface of the support plate 13. A side of the support plate 13 facing away from the fixed blade 4 is provided with a wing plate 19 which is an arc-shaped panel extending outward from the rear end portion of the blade body 11, the top of the wing plate 19 and the top of the blade body 11. The surface is flush; the inner surface of the flap 19 is formed with a concave-convex portion, and the thickness of the lower portion of the extension plate is greater than the thickness of the upper portion. The specially designed wing plate 19 can effectively improve the structural strength of the sweeping cutter 1 while avoiding the shaking or shaking of the sweeping cutter 1 during the sweeping process and the trimming process, thereby improving the stability and reliability of the trimming process. Sex.

The above content is only a preferred embodiment of the present invention, and those skilled in the art will have a change in the specific embodiment and application scope according to the idea of the present invention. The content of the present specification should not be construed as the present invention. limits.

Claims

A sewing machine for improving an automatic thread cutting mechanism, comprising a slat arm protruding above a needle car panel, a fixed sewing cover (3) fixed to a left upper portion of the sewing arm, and an outward side of the sewing arm On the left side, the inside of the sewing arm is respectively rotatably mounted with a rotary drive shaft (5) and a cutter drive shaft (2), and the cutter drive shaft (2) is fitted on the outer edge of the rotary drive shaft (5). The top of the shuttle drive shaft (5) is provided with a hook support for placing a rotary hook, characterized in that it comprises a sweeping cutter (1),

The top panel of the fixed sewing cover (3) has a needle plate (33), and the bottom surface of the needle plate (33) is fixed with a fixed blade (4);

A cutter movable space is disposed below the needle plate (33), and the cutter movable space is located between the side wall of the fixed sewing cover (3) and the cutter drive shaft (2);

The sweeping cutter (1) is fixed to the cutter drive shaft (2), the sweeping cutter (1) is disposed in the cutter movable space, and the upper portion of the sweeping cutter (1) is provided with the cutter body (11) ;

The sweeping cutter (1) moves back and forth in the cutter movable space below the fixed sewing cover (3) in one trimming process, and the cutter body (11) and the fixed blade of the sweeping cutter (1) 4) Shear fit.
A sewing machine for improving an automatic thread trimming mechanism according to claim 1, wherein said sewing machine is provided with a hook mechanism and a driving mechanism for driving said cutter drive shaft (2) at a fixed angle reciprocating rotary cutter a mechanism, a hook drive mechanism is connected to the hook drive shaft (5), and a cutter drive mechanism is connected to the cutter drive shaft (2), and the cutter drive shaft (2) drives the sweeping cutter during a trimming process ( 1) reciprocally sweeping along the curved path in the cutter movable space;

An arcuate groove (32) is defined in a bottom surface of the needle plate (33), the fixing blade (4) is fixed in the arc groove (32), and the fixing blade (4) is located at one end of the arc groove (32). In the initial state, the fixed blade (4) and the cutter body (11) are respectively located at both ends of the arcuate groove (32), and the cutter body (11) is curved along the curved path in the arcuate groove (32) when trimming The fixed blade (4) moves and is cut with the fixed blade (4) Cooperate.
A sewing machine for improving an automatic thread trimming mechanism according to claim 2, wherein said needle plate (33) is provided with a lower pin hole (31), and the lower pin hole (31) penetrates said arc downward. a slot (32), the lower pinhole (31) is located at a central position of the arcuate slot (32);

In the initial state, the cutter body (11) and the fixed blade (4) are respectively located at two sides below the lower pinhole (31); when the cutter body (11) is shear-fitted with the fixed blade (4) The cutter body (11) and the fixed blade (4) are vertically overlapped in the arc groove (32);

A movable sewn cover that can be opened or removed is fastened to the upper right portion of the sewing arm, and the fixed sewn cover (3) and the movable sewn cover are assembled to cover the upper part of the sewing arm; the cutter driving shaft (2) Set to the right of the fixed sewing cover (3).
A sewing machine with an improved automatic thread trimming mechanism according to any one of claims 1 to 3, characterized in that the sweeping cutter (1) comprises a fixing portion (12) integrally connected to the support plate (13) And the cutter body (11), the top of the fixing portion (12) is bent upward to extend out of the support plate (13), and the upper end portion of the support plate (13) is laterally bent outwardly from the cutter body ( 11);

The cutter drive shaft (2) is fixed with a jacket (21), the fixing portion (12) is fixed to the jacket (21), and the cutter body (11) is rotated back and forth when the cutter body (11) is at the cutter drive shaft (2) Reciprocating walking in the annular region of the outer edge.
A sewing machine with an improved automatic thread trimming mechanism according to claim 4, wherein one end of the cutter body (11) facing the fixed blade (4) is a front end portion, and a front end portion of the cutter body (11) is formed with The inclined or curved oblique hook line portion (15), the top surface of the cutter body (11) defines a crimping groove (16), and the outer end portion of the crimping groove (16) extends outward and penetrates to the oblique direction a hook line portion (15) for hooking the line to be cut during the sweeping of the fixed blade (4), and a trimming hole (17) is formed at the inner end portion of the crimping groove (16), The wire fitting hole (17) penetrates the blade body (11), and the wire trimming hole (17) is at the top of the hole The edge is provided as a cutting edge (10), and the fixing blade (4) is formed with a shearing portion (41), a shearing portion (41) and a cutting edge toward a bottom edge of one side of the blade body (11) The cutting edge (10) is sheared.
A sewing machine with an improved automatic thread trimming mechanism according to claim 5, characterized in that: the arcuate groove (32) is provided with a crimping piece (6), and the crimping piece (6) is fixed to the fixing Below the blade (4), a middle portion of the crimping piece (6) is bent downward to form a pressing piece elastic piece (61), and the pressing piece (61) is pressed when the cutting body (11) and the fixed blade (4) are shear-fitted. The end portion is elastically abutted against the crimping groove (16) for pressing the wire to be cut against the groove bottom of the crimping groove (16).
A sewing machine with an improved automatic thread trimming mechanism according to claim 6, wherein the oblique hook line portion (15) faces the side of the cutter drive shaft (2) as an inner portion and is connected to One side of the support plate (13) is an outer portion, and an inner portion of the oblique hook line portion (15) is formed as a tip portion, and an outer side portion of the oblique hook line portion (15) is formed with an arc-shaped retaining portion ( 18), the tip protrudes forward.
A sewing machine with an improved automatic thread trimming mechanism according to claim 7, wherein the upper and lower ends of the curved retaining wire portion (18) respectively penetrate the upper and lower sides of the cutter body (11), and the arc The first side of the wire retaining portion (18) is tangent to the oblique hook line portion (15), the second side is tangent to the support plate (13); and the shearing portion (41) protrudes from the blade body ( 11) The bottom edge, the end face of the shearing portion (41) toward the blade body (11) is a vertical plane, and the bottom surface of the shearing portion (41) is a curved surface.
A sewing machine with an improved automatic thread trimming mechanism according to claim 7, wherein said support plate (13) is a curved panel, the curved panel has a curved concave surface, and the curved concave surface of the support plate (13) Towards the cutter drive shaft (2), the cutter body (11) is located on top of the curved concave surface of the support plate (13).
A sewing machine with an improved automatic thread trimming mechanism according to claim 7, characterized in that a side of the support plate (13) facing away from the fixed blade (4) is provided with a wing (19), a flap (19) is an arc-shaped panel extending from the rear end portion of the cutter body (11) to the outside, and the flap (19) The top of the blade is flush with the top surface of the blade body (11); the inner surface of the blade (19) is formed with a concave and convex portion, and the thickness of the lower portion of the extension plate is greater than the thickness of the upper portion.