CN107916507B - Thread cutting device of sewing machine - Google Patents
Thread cutting device of sewing machine Download PDFInfo
- Publication number
- CN107916507B CN107916507B CN201610876974.5A CN201610876974A CN107916507B CN 107916507 B CN107916507 B CN 107916507B CN 201610876974 A CN201610876974 A CN 201610876974A CN 107916507 B CN107916507 B CN 107916507B
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- thread cutting
- sewing machine
- needle plate
- knife
- fixed
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- 238000009958 sewing Methods 0.000 title claims abstract description 150
- 230000009471 action Effects 0.000 claims abstract description 20
- 239000004744 fabric Substances 0.000 claims description 21
- 239000000463 material Substances 0.000 claims description 11
- 238000009966 trimming Methods 0.000 claims description 8
- 238000009434 installation Methods 0.000 claims description 6
- 230000006835 compression Effects 0.000 description 6
- 238000007906 compression Methods 0.000 description 6
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000005452 bending Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D05—SEWING; EMBROIDERING; TUFTING
- D05B—SEWING
- D05B65/00—Devices for severing the needle or lower thread
- D05B65/04—Devices for severing the needle or lower thread controlled by the workpieces
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- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Sewing Machines And Sewing (AREA)
Abstract
The utility model provides a thread cutting device of a sewing machine, which comprises a needle plate with a needle plate tongue, wherein the thread cutting device of the sewing machine comprises a fixed knife with a fixed knife blade and an upper knife with an upper knife blade, wherein the upper knife blade is meshed with the fixed knife blade and forms a thread cutting blade for cutting a suture; the thread cutting edge is positioned between the needle plate tongue and the front edge of the needle plate when the sewing machine is used for sewing. In the thread cutting device of the sewing machine, after the thread cutting action is executed by the upper cutter and the thread cutting edge formed by the engagement of the fixed cutter and the upper cutter is arranged between the needle plate tongue on the needle plate and the front edge of the needle plate, the thread cutting edge is enabled to be closer to the needle plate tongue, so that the position of the rear thread cutting sensor can be arranged on the sewing table and is closer to the needle plate tongue, the time point of thread cutting after sewing is finished is advanced, and the thread leakage phenomenon is effectively avoided.
Description
Technical Field
The utility model relates to an industrial sewing machine, in particular to a thread cutting device of the sewing machine.
Background
At present, the industrial sewing machine is provided with a front thread cutting device and a rear thread cutting device, and the front thread cutting action and the rear thread cutting action are automatically executed through an electronic control module of the sewing machine and a sensor arranged on a sewing table of the sewing machine, and generally comprise a fixed cutter and a rotatable upper cutter. For example, in an automatic control device of an industrial sewing machine disclosed in a chinese patent application publication No. 201320559872.2, the disclosed back thread cutting device includes a fixed knife provided at a side portion of a sewing table, a needle plate adjacent to the fixed knife, a cutter driving member, and a movable knife connected to the cutter driving member, the cutter driving member being capable of driving the movable knife to swing to the fixed knife to cut a thread; in addition, it is undoubtedly and uniquely known from the figures 1 and 2 of the description thereof: along the direction that the sewing cloth moved forward on the sewing table in the sewing process, the stationary knife and the movable knife are arranged at the front side of the needle plate and are close to the front end of the needle plate, so that the shortest length of the rear thread braid generated after the sewing thread is cut is as follows: the length between the needle falling hole on the needle plate and the cutting edge in the rear thread cutting device in the front-rear direction.
However, in the rear thread cutting device disclosed by the automatic control device of the industrial sewing machine, the distance between the cutting edge in the rear thread cutting device and the needle falling hole on the needle plate is long, so that the rear thread plait generated after thread cutting is too long, the thread plait formed on the sewing cloth at the next sewing is too long, the worker is required to trim again, and the efficiency is low; meanwhile, because the distance between the cutting edge in the back thread cutting device and the needle falling hole on the needle plate is longer, when the sewing machine is finished, the phenomenon that the sewing cloth is pulled forwards obliquely by a worker before the back thread cutting device does not execute the back thread cutting action or pulled backwards just after the sewing cloth leaves the presser foot, namely, the thread cutting time point is delayed, so that the thread is far away from the back thread cutting device when the back thread cutting device does not execute the back thread cutting action, and finally the condition of missed cutting is caused.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present utility model is to provide a thread cutting device for a sewing machine, which can effectively avoid the missed cutting phenomenon.
In order to achieve the above object, the present utility model provides a thread cutting device for a sewing machine, the sewing machine including a needle plate having a needle plate tongue, the thread cutting device for a sewing machine including a stationary knife having a stationary knife blade and an upper knife having an upper knife blade for performing a thread cutting action, the upper knife blade being engaged with the stationary knife blade and forming a thread cutting blade for cutting a thread; the thread cutting edge is positioned between the needle plate tongue and the front edge of the needle plate when the sewing machine is used for sewing.
Preferably, the needle plate is provided with an auxiliary feed slot positioned at the front side of the needle plate tongue, and the thread cutting edge is positioned between the needle plate tongue and the auxiliary feed slot.
Preferably, the needle plate is provided with an auxiliary feed tooth groove positioned at the front side of the tongue of the needle plate, and the thread cutting edge is positioned between the auxiliary feed tooth groove on the needle plate and the front edge of the needle plate.
Further, a supporting lug is arranged on the upper end face of the needle plate, the fixed knife is fixed on the needle plate, the upper knife is fixed on an upper knife shaft extending front and back, and the upper knife shaft is rotatably supported in the supporting lug of the needle plate.
Preferably, a retainer ring is fixed on the upper cutter shaft, a pressure spring is sleeved on the upper cutter shaft, the front end and the rear end of the pressure spring are respectively propped against the retainer ring and the supporting lug, and the pretightening force of the pressure spring enables the upper cutter to rotate towards the direction close to the fixed cutter, and then the upper cutter cutting edge of the upper cutter is meshed with the fixed cutter cutting edge of the fixed cutter.
Further, the wire cutting machine further comprises a supporting seat and a connecting shaft extending forwards and backwards, the connecting shaft is rotatably supported in the supporting seat, the connecting shaft is connected with the upper cutter shaft through a universal coupling, and the connecting shaft is driven to rotate by a wire cutting driving source.
Preferably, the wire cutting driving source is an electromagnet, the electromagnet is provided with an electromagnet core which can extend downwards, the wire cutting driving source further comprises a wire cutting crank and a crankshaft which extends forwards and backwards, the electromagnet core is connected with one end of the wire cutting crank through the crankshaft, and the connecting shaft is fixed in the other end of the wire cutting crank.
Further, the sewing machine knife set comprises a fixed knife installation seat fixed on a knife set fixing seat of the sewing machine, the fixed knife is fixed on the fixed knife installation seat, the upper knife is fixed on an upper knife shaft extending forwards and backwards, and the upper knife shaft is rotatably supported in the knife set fixing seat.
Preferably, the upper end surface of the stationary knife is provided with a line passing groove extending front and back.
Further, a line falling gap which is vertically communicated is formed between the front end of the needle plate tongue and the rear end of the fixed knife, an inclined supporting surface which is inclined downwards to the line falling gap is arranged at the rear side of the upper end face of the fixed knife, the rear edge of the inclined supporting surface forms a fixed knife blade, the fixed knife blade is lower than the needle plate tongue, and the line shearing blade formed by the meshed fixed knife blade and the upper knife blade is located below the needle plate tongue.
Preferably, the fixed knife blade on the fixed knife and the upper knife blade on the upper knife both extend leftwards and rightwards along a direction perpendicular to the cloth feeding direction of the sewing machine.
Further, the sewing machine also comprises a rear thread cutting sensor arranged on the sewing table of the sewing machine, and the rear thread cutting sensor is connected with an electronic control module of the sewing machine; when the rear thread cutting sensor detects that the sewn fabric passes through the rear thread cutting sensor, the electronic control module of the sewing machine controls the needle of the sewing machine to walk N needles again, so that the upper knife executes thread cutting action, and N is larger than or equal to 0.
As described above, the thread cutting device of the sewing machine according to the present utility model has the following advantages:
in the thread cutting device of the sewing machine, after the thread cutting action is executed by the upper cutter, the thread cutting edge formed by the engagement of the fixed cutter and the upper cutter is arranged between the needle plate tongue on the needle plate and the front edge of the needle plate, so that the thread cutting edge is closer to the needle plate tongue, the position of the rear thread cutting sensor for detecting whether the rear edge of the sewing material passes through is arranged on the sewing table and positioned at the rear side of the front edge of the needle plate, the position of the rear thread cutting sensor is moved backwards and is closer to the needle plate tongue, the time point of the rear thread cutting after the sewing is finished is advanced, and the thread leakage phenomenon is effectively avoided.
Drawings
Fig. 1 is a schematic structural view of a first embodiment of a thread cutting device of a sewing machine according to the present utility model.
Fig. 2 is an enlarged view of circle a of fig. 1.
Fig. 3 is a schematic diagram illustrating connection between the needle plate and the upper blade in fig. 1.
Fig. 4 is a schematic diagram showing connection between the needle plate and the stationary knife in fig. 1.
Fig. 5 is a schematic structural view of a second embodiment of a thread cutting device of a sewing machine according to the present utility model.
Fig. 6 is an enlarged view of circle B of fig. 5.
Fig. 7 is a schematic structural view of a third embodiment of a thread cutting device of a sewing machine according to the present utility model.
Fig. 8 is a schematic structural view of a fourth embodiment of a thread cutting device of a sewing machine according to the present utility model.
Fig. 9 is a schematic structural view of a fifth embodiment of a thread cutting device of a sewing machine according to the present utility model.
Description of element reference numerals
1. Needle plate
101. Needle plate tongue
102. Pinhole for falling needle
103. Auxiliary feed dog
104. Support lug
105. Auxiliary cloth feeding part
2. Fixed knife
21. Wire passing groove
22. Diagonal bracing surface
3. Upper knife
31. Cutting edge of wire
4. Upper cutter shaft
5. Retainer ring
6. Compression spring
7. Supporting seat
8. Connecting shaft
9. Universal coupling
10. Wire cutting driving source
11. Wire cutting crank
12. Crank axle
13. Knife set fixing seat
14. Fixed cutter mounting seat
15. Line falling gap
16. Post-trimming inductor
17. Sewing table
18. Seam starting inductor
19. Front trimming sensor
20. Upper knife supporting seat
Detailed Description
Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples.
It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or otherwise, used in the practice of the utility model, are not intended to be critical to the essential characteristics of the utility model, but are intended to fall within the spirit and scope of the utility model. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like recited in the present specification are merely for descriptive purposes and are not intended to limit the scope of the utility model, but are intended to provide relative positional changes or modifications without materially altering the technical context in which the utility model may be practiced.
In the following examples, the directions are defined as follows: the width direction of the sewing machine is defined as the front-back direction, the length direction of the sewing machine is defined as the left-right direction, the height direction of the sewing machine is defined as the up-down direction, and the front direction is the moving direction of the cloth on the sewing table 17 during the sewing process, the head of the sewing machine is located at the left side of the sewing machine, and the tail of the sewing machine is located at the right side of the sewing machine.
The utility model provides a thread cutting device of a sewing machine, which is arranged on various industrial sewing machines, is particularly suitable for rear thread cutting in an overedger, is used for cutting a suture after sewing is finished, and effectively shortens the length of a rear thread braid formed at the rear edge of a sewing material after thread cutting, so that the thread cutting device of the sewing machine is the rear thread cutting device in the sewing machine. As shown in fig. 1 and 2, or fig. 5 and 6, the sewing machine with the thread cutting device of the sewing machine comprises a needle plate 1 with a needle plate tongue 101, the needle plate tongue 101 is positioned on the right side of the needle plate 1, the needle plate 1 is provided with needle falling holes 102 positioned on the left side of the needle plate tongue 101, the needle falling holes 102 penetrate through the needle plate 1 up and down, and the number of the needle falling holes 102 is the same as that of the needles in the sewing machine, for example: when two needles are installed in the sewing machine, two needle dropping holes 102 are correspondingly arranged on the needle plate 1, and as shown in fig. 2, the two needle dropping holes 102 are arranged side by side left and right. The needle plate 1 is mounted on a sewing table 17 of a sewing machine. Meanwhile, a seam lifting sensor 18, a front thread cutting sensor 19 and a rear thread cutting sensor 16 are arranged on the upper end surface of the seam table 17, the seam lifting sensor 18, the front thread cutting sensor 19 and the rear thread cutting sensor 16 are all connected with an electronic control module of a sewing machine, and the seam lifting sensor 18, the front thread cutting sensor 19 and the rear thread cutting sensor 16 are sequentially arranged from back to front; wherein, when the front edge of the sewing material passes through the seam lifting sensor 18, the sewing machine electronic control module controls the driving motor to rotate so as to start sewing; when the front edge of the sewing material passes through the front thread cutting sensor 19, the sewing machine electronic control module controls the front thread cutting device in the sewing machine to act, and cuts off the thread to generate a front thread braid formed at the front edge of the sewing material; when the rear edge of the sewing material passes through the rear thread cutting sensor 16, the sewing machine electronic control module controls the rear thread cutting device in the sewing machine to act so as to cut the thread and generate a rear thread braid formed at the rear edge of the sewing material. In addition, the needle plate 1 may be further provided with an auxiliary feed dog 103 located at the front side of the needle plate tongue 1, where the auxiliary feed dog 103 extends in the front-back direction and penetrates the needle plate 1 up and down, and the auxiliary feed dog 103 may accommodate the auxiliary feed dog to be exposed upwards, and the auxiliary feed dog in the sewing machine reciprocates back and forth to realize auxiliary feed.
The thread cutting device of the sewing machine for executing the back thread cutting action comprises a fixed cutter 2 with a fixed cutter blade and an upper cutter 3 with an upper cutter blade for executing the thread cutting action, wherein after the upper cutter 3 executes the thread cutting action, the upper cutter blade is meshed with the fixed cutter blade and forms a thread cutting blade 31 for cutting a suture thread, and the thread cutting blade 31 is positioned behind the back thread cutting sensor 16 or aligned on the left and right; in order to effectively shorten the length of a rear braid generated after trimming is finished, as shown in fig. 2 or 6, the utility model sets the stationary knife 2, the upper knife 3 and a trimming blade 31 formed after the engagement of the stationary knife 2 and the upper knife 3 between the needle plate tongue 101 on the needle plate 1 and the front edge of the needle plate 1 along the forward cloth feeding direction when the sewing machine is sewing, i.e. along the feed dog of the sewing machine. Thus, the stationary blade 2, the upper blade 3 and the wire cutting edge 31 may have the following several mounting positions:
1. as shown in fig. 1, 5 or 7, the needle plate 1 is provided with an auxiliary feed slot 103 positioned on the front side of the needle plate tongue 101, and the stationary knife 2, the upper knife 3 and the thread cutting blade 31 are all arranged between the needle plate tongue 101 and the auxiliary feed slot 103 on the needle plate 1, so that the stationary knife 2, the upper knife 3 and the thread cutting blade 31 are all positioned on the front side of the needle plate tongue 101 and on the rear side of the auxiliary feed slot 103.
2. As shown in fig. 8, the needle plate 1 has no auxiliary feed slot 103, and the fixed blade 2, the upper blade 3 and the thread cutting blade 31 are disposed between the needle plate tongue 101 on the needle plate 1 and the front edge of the needle plate 1, so that the fixed blade 2, the upper blade 3 and the thread cutting blade 31 are disposed on the front side of the needle plate tongue 101 and the rear side of the front edge of the needle plate 1.
3. As shown in fig. 9, the needle plate 1 is provided with an auxiliary feed slot 103 located on the front side of the needle plate tongue 101, and the stationary knife 2, the upper knife 3 and the thread cutting blade 31 are all disposed between the auxiliary feed slot 103 and the front edge of the needle plate 1, so that the stationary knife 2, the upper knife 3 and the thread cutting blade 31 are all located on the front side of the auxiliary feed slot 103 and on the rear side of the front edge of the needle plate 1.
In the thread cutting device of the sewing machine, since the fixed knife 2, the upper knife 3 and the thread cutting edge 31 are all arranged between the needle board tongue 101 on the needle board 1 and the front edge of the needle board 1, compared with the prior art, the position of the fixed knife 2, the upper knife 3 and the thread cutting edge 31 is arranged backwards in the direction close to the needle board tongue 101, therefore, the position of the rear thread cutting sensor 16 is synchronously arranged backwards in the direction close to the needle board tongue 101, the rear thread cutting sensor 16 can be arranged on the upper end face of the sewing table 17 and positioned at the rear side of the front edge of the needle board 1, the rear thread cutting sensor 16 is closer to the needle board tongue 101 and the needle falling hole 102, or the distance between the rear thread cutting sensor 16 and the needle board tongue 101 in the front-rear direction is greatly shortened compared with the prior art. At this time, after the sewing is finished, the time point at which the rear thread cutting sensor 16 detects that the rear edge of the sewn material passes is advanced compared with the prior art, so that the time point at which the thread cutting device of the sewing machine executes the rear thread cutting action is also advanced, and therefore the thread is cut when the worker pulls the sewn fabric obliquely forwards or backwards, and the phenomenon that the sewn fabric is pulled obliquely forwards or backwards before the thread cutting device of the sewing machine executes the thread cutting action after each sewing is finished is effectively avoided. Further, after sewing is finished, an electric control module of the sewing machine controls the upper knife 3 to execute thread cutting action and is meshed with the fixed knife 2, so that a thread is cut by the thread cutting edge 31, the minimum length of a rear thread braid generated after thread cutting is the distance between the rear thread cutting sensor 16 and the thread cutting edge 31 in the front-rear direction, and the positions of the fixed knife 2, the upper knife 3 and the thread cutting edge 31 are set backwards and are closer to the rear thread cutting sensor 16 on the needle plate 1, so that the distance between the rear thread cutting sensor 16 and the thread cutting edge 31 in the front-rear direction can be shortened, and the length of the rear thread braid generated after thread cutting by the thread cutting device is greatly reduced; when the rear wire cutting sensor 16 is flush with the wire cutting edge 31, the length of the rear wire strand generated can be zero.
In the present utility model, the mounting manners of the fixed blade 2 and the upper blade 3 are three embodiments, respectively: in the first embodiment, the fixed knife 2 and the upper knife 3 are all arranged on the needle plate 1 of the sewing machine, and then the fixed knife 2 and the upper knife 3 are integrated with the needle plate 1; in the second embodiment, the fixed knife 2 and the upper knife 3 are both arranged on a knife set fixing seat 13 of the sewing machine; in the third embodiment, the fixed knife 2 and the upper knife 3 are all arranged on an upper knife supporting seat 20 of the sewing machine.
In the first embodiment, the stationary knife 2 and the upper knife 3 are mounted on the needle plate 1 of the sewing machine, and in this case, as shown in fig. 1 to 4, the needle plate 1 is provided with an auxiliary feeding portion 105 for opening the auxiliary feeding teeth 103, so that the auxiliary feeding portion 105 is located at the right front side of the needle plate 1, and the stationary knife 2 is fixed to the rear end surface of the auxiliary feeding portion 105 of the needle plate 1 by screws, so that the stationary knife 2 is mounted on the needle plate 1; the needle plate 1 is provided with a supporting lug 104 at the right edge of the front side of the upper end surface of the auxiliary cloth feeding part 105, the upper surface of the supporting lug 104 is a smooth arc surface, a rotatable and front-back extending upper cutter shaft 4 is supported in the supporting lug 104, and the upper cutter 3 is fixed at the rear end of the upper cutter shaft 4, so that the upper cutter 3 is mounted on the needle plate 1 and supported by the needle plate 1. Or, as shown in fig. 9, a notch is formed on the needle plate 1 at the front side of the auxiliary feed dog 103, the fixed knife 2 is arranged at the notch and is fixed on the needle plate 1 by a screw, and the supporting lug 104 is arranged at the front side of the notch.
Preferably, as shown in fig. 3, a retainer ring 5 located at the front side of the supporting lug 104 is fixed on the upper cutter shaft 4, a compression spring 6 extending axially from front to back is further sleeved on the upper cutter shaft 4, the front end of the compression spring 6 abuts against the retainer ring 5, the rear end of the compression spring 6 abuts against the supporting lug 104, and after the upper cutter 3 rotates towards the direction close to the fixed cutter 2 by the pretightening force of the compression spring 6, the upper cutter cutting edge of the upper cutter 2 and the fixed cutter cutting edge of the fixed cutter 2 can be accurately meshed, so that the wire cutting function is accurately realized. In order to facilitate the installation of the retainer ring 5 on the upper cutter shaft 4, the retainer ring 5 is an open retainer ring and is tightly matched and fixed with the upper cutter shaft 4, so the retainer ring 5 can be a clamp spring.
Because the upper cutter shaft 4 is supported by the needle plate 1, the diameter of the upper cutter shaft 4 is smaller, the upper cutter shaft 4 is an slender shaft, in order to effectively prevent the phenomenon that the upper cutter 3 cannot accurately engage with the fixed cutter 2 due to bending, deformation and the like of the slender upper cutter shaft 4, as shown in fig. 1, the thread cutting device of the sewing machine further comprises a supporting seat 7 and a connecting shaft 8 extending forwards and backwards, the connecting shaft 8 is rotatably supported in the supporting seat 7, the supporting seat 7 is fixed on a shell of the sewing machine, the rear end of the connecting shaft 8 is connected with the front end of the upper cutter shaft 4 through a universal coupler 9, and the connecting shaft 8 is driven to rotate by a thread cutting driving source 10. Through the structure, the axial length of the upper cutter shaft 4 can be effectively shortened, further the phenomena of bending, deformation and the like of the upper cutter shaft 4 are avoided, the upper cutter 3 and the fixed cutter 2 can be ensured to be accurately meshed to cut a suture, and the reliability and stability of thread cutting are improved. In addition, the above structure can conveniently realize concentric installation between the upper cutter shaft 4 and the connecting shaft 8, namely: firstly, assembling an upper cutter shaft 4, an upper cutter 3, a needle plate 1 and a fixed cutter 2, then, assembling a connecting shaft 8 and a thread cutting driving source 10, and finally, connecting the upper cutter shaft 4 with the connecting shaft 8 by using a universal coupler 9; because of processing errors and adjustment when the needle plate 1 is assembled, concentricity cannot be well ensured between the upper cutter shaft 4 and the connecting shaft 8, after the upper cutter shaft 4 and the connecting shaft 8 are connected through the universal coupler 9, the problem caused by concentricity between the upper cutter shaft 4 and the connecting shaft 8 can be well eliminated, the accuracy of the wire cutting action of the upper cutter 3 is ensured, and effective support of the upper cutter shaft 4 and the connecting shaft 8 can be easily realized.
The wire cutting driving source 10 can be a motor and directly or indirectly drives the connecting shaft 8 to rotate for a certain angle; the wire cutting driving source 10 may also be an electromagnet, and indirectly drives the connecting shaft 8 to rotate for a certain angle. In this embodiment, the thread cutting driving source 10 adopts an electromagnet, at this time, as shown in fig. 1, the electromagnet has an electromagnet core that can extend downward, the thread cutting device of the sewing machine further includes a thread cutting crank 11 and a crank shaft 12 that extends back and forth, the electromagnet core is connected with the right end of the thread cutting crank 11 through the crank shaft 12, and the connecting shaft 8 is fixed in the left end of the thread cutting crank 11. When the thread is cut, the electromagnet is electrified, the electromagnet iron core stretches downwards to drive the right end of the thread cutting crank 11 to swing downwards by taking the axis of the connecting shaft 8 as a central line, and then the connecting shaft 8 is driven to rotate by a certain angle, and the connecting shaft 8 drives the upper cutter shaft 4 and the upper cutter 3 to synchronously rotate by a certain angle, so that the upper cutter 3 is meshed with the fixed cutter 2, and the thread is cut.
In the second embodiment, the fixed knife 2 and the upper knife 3 are mounted on the knife set fixing seat 13 of the sewing machine, and at this time, as shown in fig. 5 and 6, the thread trimming device of the sewing machine further comprises a fixed knife mounting seat 14 fixed on the knife set fixing seat 13 of the sewing machine, the fixed knife 2 is fixed on the fixed knife mounting seat 14, the upper knife 3 is fixed on the rear end of the upper knife shaft 4, and the upper knife shaft 4 is rotatably supported in the knife set fixing seat 13. Because the cutter set fixing seat 13 of the sewing machine provides support for the upper cutter shaft 4, the diameter of the upper cutter shaft 4 is larger, the upper cutter shaft 4 can be properly thickened and lengthened, and the supporting point of the cutter set fixing seat 13 for supporting the upper cutter shaft 4 is positioned in the middle of the upper cutter shaft 4, so that the cutting wire driving source 10 can be directly connected with the front end of the upper cutter shaft 4, and the connecting shaft 8 can be directly or indirectly driven to rotate for a certain angle. Similarly, the wire cutting driving source 10 may be a motor or an electromagnet, and when the wire cutting driving source 10 is an electromagnet, the wire cutting driving source 10 drives the upper cutter shaft 4 to rotate through the wire cutting crank 11 and the crank shaft 12.
In the third embodiment, the fixed knife 2 and the upper knife 3 are all mounted on the upper knife supporting seat 20 of the sewing machine, at this time, as shown in fig. 7 or 8, the upper knife supporting seat 20 and the needle plate 1 are two mutually independent parts, the upper knife supporting seat 20 is fixed on the right side surface of the needle plate 1 through screws, the fixed knife 2 is fixed on the rear end surface of the upper knife supporting seat 20, the upper knife 3 is fixed on the rear end of the upper knife shaft 4, and the upper knife shaft 4 is rotatably supported in the upper knife supporting seat 20. In this case, the upper cutter shaft 4 is also an elongated shaft, and therefore, similarly to the first embodiment, the retainer ring 5, the compression spring 6, the universal joint 9, and the connecting shaft 8 for connecting with the wire cutting driving source 10 are required.
Further, in the thread cutting device of the sewing machine, the fixed knife blade of the fixed knife 2 and the upper knife blade on the upper knife 3 both extend leftwards and rightwards along the direction perpendicular to the cloth feeding direction of the sewing machine; the upper blade 3 has a substantially V-shaped cross section, and the tip of the lower end of the upper blade 3 forms the upper blade edge. As shown in fig. 2 and fig. 4, the upper end surface of the stationary knife 2 is provided with a wire passing groove 21 extending back and forth, so that the wire braid can smoothly pass through the position, and the wire braid is prevented from being blocked and plugged.
Preferably, as shown in fig. 3, 4 and 6, a thread dropping gap 15 penetrating up and down is formed between the front end of the needle plate tongue 101 and the rear end of the fixed knife 2, a diagonal bracing surface 22 inclined to the thread dropping gap 15 is arranged at the rear side of the upper end surface of the fixed knife 2, the rear edge of the diagonal bracing surface 22 forms the fixed knife blade, the fixed knife blade is lower than the needle plate tongue 101, and the thread cutting blade 31 formed by the meshed fixed knife blade and upper knife blade is positioned below the needle plate tongue 101; the front end of the inclined supporting surface 22 is flush with the upper end surface of the fixed knife 2, and the upper end surface of the fixed knife 2 is flush with the upper end surface of the needle plate 1 or slightly lower than the upper end surface of the needle plate 1 so as to facilitate the smooth passing of the sewn fabric. The thread after completion of sewing can be accurately landed on the diagonal stay 22 by the thread landing slit 15, the diagonal stay 22 and the mounting position of the fixed knife blade, so that the thread supported by the diagonal stay 22 can be accurately cut after the position of the thread cutting blade 31 is moved down.
Further, after the sewing is finished, the rear thread cutting sensor 16 detects that the sewn fabric passes through, and the rear thread cutting sensor 16 is not covered by the sewn fabric, at this time, the electronic control module of the sewing machine controls the needle of the sewing machine to walk N needles again, so that the upper knife 3 executes thread cutting action, and N is equal to or greater than 0. When n=0, it means that the upper knife 3 rotates downward to cut the suture just after the suture passes the rear thread cutting sensor 16, and the braid is the shortest length. However, some manufacturers specify the length of the wire braid, and the corresponding wire braid length can be obtained by setting the size of N, where n=1, 2, 3 …; when the rear thread cutting sensor 16 detects that the stitching material just passes through the rear thread cutting sensor 16 forwards, after the needle of the sewing machine walks again for N needles, the upper knife 3 rotates downwards to cut the stitching thread, and the length of the thread braid is the distance between the thread cutting edge 31 and the rear thread cutting sensor 16 in the front-rear direction (namely the shortest length of the thread braid) +the length of the thread braid formed by the walking of the needle by N needles, so that the aim of controlling the length of the rear thread braid is fulfilled, and the larger N is, the longer the generated rear thread braid is.
Similarly, when the front thread cutting sensor 19 detects that the sewn fabric passes, the electronic control module of the sewing machine controls the needle of the sewing machine to walk again for M needles, so that the front thread cutting device of the sewing machine executes thread cutting action, and the length of the front thread braid is controlled; the larger M, the shorter the length of the front wire strand produced.
In summary, in the utility model, after the fixed knife 2, the upper knife 3 and the thread cutting edge 31 are all arranged between the needle plate tongue 101 on the needle plate 1 and the front edge of the needle plate 1, the distance between the thread cutting edge 31 and the rear thread cutting sensor 16 in the front-rear direction and the distance L between the thread cutting edge 31 and the needle falling hole 102 on the needle plate 1 in the front-rear direction can be greatly shortened, so that the length of a thread braid generated after the thread cutting of the thread cutting device is finished is greatly reduced, and particularly, the phenomenon that the thread cutting is missed due to the fact that a worker pulls the sewn fabric forwards or backwards before the thread cutting device of the sewing machine executes the thread cutting action after each sewing is finished can be effectively avoided.
Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (11)
1. The utility model provides a sewing machine cuts line device, sewing machine includes faller (1) that has faller tongue (101) and installs back thread cutting inductor (16) on sewing machine seam platform (17), and this back thread cutting inductor (16) are connected its characterized in that with sewing machine's electronic control module: the thread cutting device of the sewing machine comprises a fixed cutter (2) with a fixed cutter blade and an upper cutter (3) with an upper cutter blade, wherein the upper cutter blade is meshed with the fixed cutter blade and forms a thread cutting blade (31) for cutting a suture; the sewing machine is characterized in that the thread cutting edge (31) is positioned between a needle plate tongue (101) on the needle plate (1) and the front edge of the needle plate (1) along the forward feeding direction of the sewing material when the sewing machine is used for sewing, the rear thread cutting sensor (16) is positioned at the rear side of the front edge of the needle plate (1), the distance between the rear thread cutting sensor (16) and the needle plate tongue (101) in the front-rear direction is shortened, and the time point when the rear thread cutting sensor (16) detects that the rear edge of the sewing material passes is advanced; when the rear thread cutting sensor (16) detects that the sewn fabric passes through the rear thread cutting sensor (16), an electronic control module of the sewing machine controls the upper knife (3) to execute thread cutting action;
a thread dropping gap (15) which is vertically communicated is formed between the front end of the needle plate tongue (101) and the rear end of the fixed knife (2), a diagonal bracing surface (22) which is inclined downwards to the thread dropping gap (15) is arranged at the rear side of the upper end face of the fixed knife (2), a fixed knife blade is formed at the rear edge of the diagonal bracing surface (22), the fixed knife blade is lower than the needle plate tongue (101), and a thread cutting blade (31) formed by the meshed fixed knife blade and the upper knife blade is positioned below the needle plate tongue (101).
2. The thread cutting device of a sewing machine of claim 1, wherein: the needle plate (1) is provided with an auxiliary feed tooth groove (103) positioned at the front side of the needle plate tongue (101), and the thread cutting blade (31) is positioned between the needle plate tongue (101) and the auxiliary feed tooth groove (103) on the needle plate (1).
3. The thread cutting device of a sewing machine of claim 1, wherein: the needle plate (1) is provided with an auxiliary feed tooth groove (103) positioned at the front side of the needle plate tongue (101), and the thread cutting blade (31) is positioned between the auxiliary feed tooth groove (103) on the needle plate (1) and the front edge of the needle plate (1).
4. A sewing machine thread trimming apparatus as recited in any one of claims 1-3, wherein: the upper end face of the needle plate (1) is provided with a supporting lug (104), the fixed knife (2) is fixed on the needle plate (1), the upper knife (3) is fixed on an upper knife shaft (4) extending forwards and backwards, and the upper knife shaft (4) is rotatably supported in the supporting lug (104) of the needle plate (1).
5. The thread cutting device of a sewing machine of claim 4, wherein: a check ring (5) is fixed on the upper cutter shaft (4), a pressure spring (6) is sleeved on the upper cutter shaft (4), the front end and the rear end of the pressure spring (6) are respectively propped against the check ring (5) and the supporting lug (104), and the pretightening force of the pressure spring (6) enables the upper cutter (3) to rotate towards the direction close to the fixed cutter (2), and then the upper cutter edge of the upper cutter (3) is meshed with the fixed cutter edge of the fixed cutter (2).
6. The thread cutting device of a sewing machine of claim 4, wherein: the wire cutting machine further comprises a supporting seat (7) and a connecting shaft (8) extending forwards and backwards, the connecting shaft (8) is rotatably supported in the supporting seat (7), the connecting shaft (8) is connected with the upper cutter shaft (4) through a universal coupler (9), and the connecting shaft (8) is driven to rotate by a wire cutting driving source (10).
7. The thread cutting device of a sewing machine of claim 6, wherein: the wire cutting driving source (10) is an electromagnet, the electromagnet is provided with an electromagnet core which can extend downwards, the wire cutting driving source further comprises a wire cutting crank (11) and a crankshaft (12) which extends forwards and backwards, the electromagnet core is connected with one end of the wire cutting crank (11) through the crankshaft (12), and the connecting shaft (8) is fixed in the other end of the wire cutting crank (11).
8. A sewing machine thread trimming apparatus as recited in any one of claims 1-3, wherein: the sewing machine knife set comprises a sewing machine knife set fixing seat (13), and is characterized by further comprising a fixed knife installation seat (14) fixed on the sewing machine knife set fixing seat (13), wherein the fixed knife (2) is fixed on the fixed knife installation seat (14), the upper knife (3) is fixed on an upper knife shaft (4) extending front and back, and the upper knife shaft (4) is rotatably supported in the knife set fixing seat (13).
9. A sewing machine thread trimming apparatus as recited in any one of claims 1-3, wherein: the upper end face of the fixed knife (2) is provided with a line passing groove (21) extending forwards and backwards.
10. The thread cutting device of a sewing machine of claim 1, wherein: the fixed knife blade of the fixed knife (2) and the upper knife blade of the upper knife (3) extend leftwards and rightwards along the direction perpendicular to the cloth feeding direction of the sewing machine.
11. The thread cutting device of a sewing machine of claim 1, wherein: when the rear thread cutting sensor (16) detects that the sewn fabric passes through the rear thread cutting sensor (16), the electronic control module of the sewing machine controls the needle of the sewing machine to walk N needles again, and then the upper knife (3) executes thread cutting action, and N is not less than 0.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610876974.5A CN107916507B (en) | 2016-10-08 | 2016-10-08 | Thread cutting device of sewing machine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610876974.5A CN107916507B (en) | 2016-10-08 | 2016-10-08 | Thread cutting device of sewing machine |
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| CN107916507B true CN107916507B (en) | 2023-10-31 |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108625054A (en) * | 2018-07-06 | 2018-10-09 | 吴江市震宇缝制设备有限公司 | A kind of thread cutting mechanism of sewing machine |
| CN111197207A (en) * | 2018-11-20 | 2020-05-26 | 杰克缝纫机股份有限公司 | Thread cutting control mechanism and sewing machine |
| CN112921523B (en) * | 2019-12-05 | 2022-05-17 | 杰克科技股份有限公司 | Sewing machine and sewing machine control method |
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Address after: 318010 No. 1008, east section of Donghai Avenue, Sanjia, Jiaojiang District, Taizhou City, Zhejiang Province Applicant after: Jack Technology Co.,Ltd. Address before: 318010 No. 15 Airport South Road, Jiaojiang District, Zhejiang, Taizhou Applicant before: JACK SEWING MACHINE Co.,Ltd. |
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