CN209907016U

CN209907016U - Double-moving-knife thread shearing device of sewing machine

Info

Publication number: CN209907016U
Application number: CN201920469058.9U
Authority: CN
Inventors: 王跃; 潘军
Original assignee: Bullmer Electromechanical Technology Co Ltd
Current assignee: Bullmer Electromechanical Technology Co Ltd
Priority date: 2019-04-09
Filing date: 2019-04-09
Publication date: 2020-01-07
Anticipated expiration: 2029-04-09

Abstract

The utility model provides a double acting sword thread trimmer devices of sewing machine, double acting sword thread trimmer devices of sewing machine includes that the first sword that moves, the second moves the sword, electrical control module, detect the sensor, be fixed in the second and move the sword and can be detected the response piece by that the sensor sensed, first driving source, the second driving source, first drive assembly, and second drive assembly, first driving source moves the sword through first drive assembly and first and links to each other, the second driving source moves the sword through second drive assembly and second and links to each other, detect the sensor, first driving source and second driving source all link to each other with electrical control module. The electric control module accurately controls the time point of the stop action of the second driving source when the second movable knife moves forward according to the change of the output signal of the detection sensor, so that the second limit position of the forward movement of the second movable knife is accurately controlled, the second movable knife moves forward to a thread shearing point, and the thread shearing effect of the short thread head can be stably realized; the motion between the first movable knife and the second movable knife has no linkage, so the application is easy to realize.

Description

Double-moving-knife thread shearing device of sewing machine

Technical Field

The utility model relates to a sewing machine.

The utility model particularly relates to a double-acting-knife thread trimming device of a sewing machine and a double-acting-knife thread trimming method of the sewing machine by using the double-acting-knife thread trimming device of the sewing machine.

Background

At present, the requirement of customers on the thread ends of clothes is higher and higher, the length of the thread ends directly influences the attractiveness of the clothes, and in addition, the thread ends are too long and are easy to have the hidden trouble of thread loosening caused by pulling the thread ends. In order to solve the problem of overlong thread ends, the common practice of the current clothing factories is as follows: a procedure of manually trimming thread ends is added, but the method increases the labor cost of garment making and reduces the production efficiency of garment making; alternatively, some sewing machine manufacturers also make improvements in the thread trimming device of the sewing machine to achieve the thread trimming effect of the stub. In the prior art, a thread cutting device in a sewing machine mainly has two forms: single-moving-knife thread-cutting device and double-moving-knife thread-cutting device. The fixed knife is arranged on the needle plate, the needle hole is arranged on the needle plate, the fixed knife is arranged on the needle plate, and the fixed knife is arranged on the needle plate. The double-action-knife thread cutting device is provided with two movable knives, such as: the double-knife thread trimming mechanism of the sewing machine disclosed in the chinese utility model patent specification with the application number of 201520727456.8 adopts a driving source to drive a first moving knife and a second moving knife simultaneously, thereby realizing thread trimming; however, the double-action-knife thread cutting mechanism has the following defects: 1. the two moving blades are connected to the same driving rod through a mechanical structure, so that the two moving blades are in a linkage structure and act simultaneously, and certain mutual limitation exists between the two moving blades; 2. the double-knife thread cutting mechanism is connected through a plurality of connecting rod mechanisms, and the ideal thread cutting position, the limit of each part and the flexible movement of each part are realized at a needle falling hole by matching among the parts, so that the double-knife thread cutting mechanism has over-strong relevance and poor adjustability; 3. the two movable cutters act simultaneously to realize thread cutting in a matching way, so that the thread cutting effect is influenced by the two movable cutters, and the thread cutting stability is poor; 4. the line cutting is realized at the needle falling hole, so that the meeting and the meshing of the cutting edges of the two movable cutters at the needle falling hole in the return stroke process are required to be ensured, the limit advancing position of the second movable cutter is also required to be ensured to be positioned right below the needle falling hole, but the ideal line cutting position is difficult to adjust due to the relevance of the actions of the two movable cutters, and the line cutting effect is not ideal.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention provides a double-knife thread trimming device for a sewing machine, which can precisely control the thread trimming position and is easy to implement.

In order to achieve the purpose, the utility model provides a double-movable-knife thread trimming device of a sewing machine, which comprises a first movable knife and a second movable knife which are movably arranged on a main needle plate, wherein a first cutting edge on the first movable knife and a second cutting edge on the second movable knife can be occluded; double-acting sword thread trimming device of sewing machine still includes electrical module, installs in the detection sensor of sewing machine casing, is fixed in the second and moves the sword and can be detected the sensor to sense by response piece, first driving source, second driving source, first drive assembly and second drive assembly, first driving source moves the sword through first drive assembly and first moving and links to each other, drives first moving sword motion, the second driving source moves the sword through second drive assembly and second and links to each other, drives the second and moves the sword motion, it all links to each other with electrical module to detect sensor, first driving source and second driving source.

Further, the double-knife thread shearing device of the sewing machine further comprises a sensor mounting plate provided with a mounting adjusting groove, the mounting adjusting groove is a waist-shaped groove, the extending direction of the mounting adjusting groove is consistent with the moving direction of the second moving knife, the sensor mounting plate is fixed on the shell of the sewing machine through a fixing screw, the fixing screw penetrates through the mounting adjusting groove, and the detection sensor is fixed on the sensor mounting plate.

Further, the detection sensor is a photoelectric sensor, and the sensed member is a photosensitive sheet.

Further, the first drive source and the second drive source are both motors.

Further, the first movable knife is rotatably arranged on the main needle plate; first drive assembly is including rotating the actuating frame, first connecting rod and second connecting rod, it rotationally installs in the main needle board to rotate actuating frame and first connecting rod coaxial line, it is fixed mutually by first driving source drive swing, just rotate actuating frame and first connecting rod to rotate the actuating frame, the both ends of second connecting rod are articulated with first connecting rod and first sword that moves respectively.

Further, the first driving source has a rotatable first driving portion; the first driving assembly further comprises a thread trimming cam fixed on the first driving portion, a connecting plate rotatably mounted on the sewing machine shell and a connecting pull rod, two ends of the connecting plate are hinged to the thread trimming cam and one end of the connecting pull rod respectively, and one end of the connecting pull rod is hinged to the rotating driving frame.

Furthermore, the second movable knife is rotatably arranged on the main needle plate, the second driving source is provided with a rotatable second driving part, and the end part of the second driving part is provided with a threaded hole; the second drive assembly comprises a universal joint and a third connecting rod, one end of the universal joint is a ball joint with a screw rod part, the other end of the universal joint is a ball groove joint with a screw hole, one end of the third connecting rod is provided with a screw rod part, the screw rod part of the ball joint is in threaded connection with the screw hole of the second drive part, the screw rod part of the third connecting rod is in threaded connection with the screw hole of the ball groove joint, and the other end of the third connecting rod is hinged with the second movable cutter.

Furthermore, the first movable knife comprises a line splitting part, a line hooking part and a line sliding part, wherein the line splitting part and the line hooking part are arranged oppositely, the line sliding part is connected between the line splitting part and the line hooking part, the first knife edge is close to the intersection of the line splitting part and the line sliding part, a line accommodating groove is formed in the upper end face of the first movable knife facing the second movable knife, one end of the line accommodating groove extends to the second knife edge, and the other end of the line accommodating groove extends to the line hooking part.

As described above, the double-moving-blade thread cutting device of the sewing machine of the present invention has the following advantageous effects:

in the application, through the mutual matching of the detection sensor and the sensed part, the electric control module can accurately control the time point of the second driving source stopping when the second movable knife moves forward according to the change of the output signal of the detection sensor, so as to accurately control the second limit position of the second movable knife, the installation position of the detection sensor ensures that the second movable knife happens to move forward to a trimming point when the output signal of the detection sensor changes, further accurately control the second limit position of the second movable knife, and the trimming effect of the short wire end can be stably realized; in addition, the first movable knife and the second movable knife are respectively driven by the first driving source and the second driving source, so that the movement between the first movable knife and the second movable knife has no linkage, and the double-movable-knife thread cutting device of the sewing machine is easy to realize.

Drawings

FIG. 1 is a schematic view of the double-knife thread trimmer device of the sewing machine according to the present application.

Fig. 2 to 4 are schematic structural diagrams of fig. 1 at different viewing angles after omitting the first driving source, the trimming cam, the connecting plate and the connecting rod.

Fig. 5 is a schematic structural diagram of the first moving blade in the present application.

Fig. 6 is a schematic structural view of the second moving blade in the present application.

Fig. 7 is a state diagram of the present application when the first movable blade and the second movable blade are engaged.

Fig. 8 is a schematic diagram of the electronic control module controlling the second driving source to operate according to the present application.

Description of the element reference numerals

1 Main needle board

2 first moving knife

21 first blade

22 branching part

23 hook part

24 slide wire part

25 wire-containing groove

3 second moving knife

31 second blade

4 detecting sensor

5 by the response piece

6 first driving source

61 first drive part

7 second driving source

71 second driving part

8 sensor mounting plate

81 installation regulating groove

9 rotating driving frame

91 locking adjusting groove

10 first link

11 second connecting rod

12 trimming cam

13 connecting plate

14 connecting pull rod

15 universal joint

151 ball joint

152 ball groove joint

16 third connecting rod

17 small needle plate

171 needle dropping hole

18 first axial position screw

19 second axial screw

20 third axial position screw

21 fourth axial position screw

22 locking screw

Detailed Description

The following description is provided for illustrative purposes, and other advantages and features of the present invention will become apparent to those skilled in the art from the following detailed description.

It should be understood that the drawings of the present application are only used to match the contents disclosed in the specification, so as to be known and read by those skilled in the art, and not to limit the practical limitations of the present invention, so that the present application does not have any technical significance, and any modification of the structure, change of the ratio relationship, or adjustment of the size should still fall within the scope of the present application without affecting the function and the achievable purpose of the present application. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description only, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof are considered as the scope of the present invention without substantial changes in the technical content.

The application provides a double-moving-knife thread shearing device of a sewing machine, which is arranged in the sewing machine and is used for shearing off a thread after sewing is finished; for convenience of description, the height direction of the sewing machine is defined as the up-down direction. As shown in fig. 1 to 4, the sewing machine includes a main needle plate 1 and a small needle plate 17 attached to the main needle plate 1, the small needle plate 17 has a needle drop hole 171 penetrating vertically, the center of the needle drop hole 171 and the vicinity of the center of the needle drop hole 171 are within a range of a thread cutting point of a double-blade thread cutting device of the sewing machine, and the double-blade thread cutting device of the sewing machine cuts a thread within the range of the thread cutting point, thereby shortening the length of a thread end after thread cutting and realizing a thread cutting effect of the thread end.

As shown in fig. 1 to 6, the double-knife thread cutting device of the sewing machine includes a first moving knife 2 having a first blade 21, a second moving knife 3 having a second blade 31, an electric control module, a detection sensor 4, a sensed member 5, a first driving source 6, a second driving source 7, a first driving assembly, and a second driving assembly. The first movable knife 2 and the second movable knife 3 are movably mounted on the main needle plate 1, and the first knife edge 21 on the first movable knife 2 and the second knife edge 31 on the second movable knife 3 can be meshed at a certain trimming point within the trimming point range; the detection sensor 4 is arranged on the sewing machine shell; the sensed part 5 is fixed on the second movable knife 3 through a screw and moves along with the second movable knife 3; the first driving source 6 is connected with the first movable blade 2 through a first driving component and drives the first movable blade 2 to move; the second driving source 7 is connected with the second movable blade 3 through a second driving component and drives the second movable blade 3 to move; the detection sensor 4, the first drive source 6 and the second drive source 7 are all connected to the electronic control module. In the double-knife thread trimming device of the sewing machine, when the second moving knife 3 is positioned in a certain range, the detection sensor 4 can sense the sensed part 5; when the second moving blade 3 is not at the position within the range, the detection sensor 4 cannot sense the sensed part 5; in the embodiment, when the double-knife thread trimming device of the sewing machine does not perform thread trimming, the first movable knife 2 and the second movable knife 3 are positioned at respective initial positions, and the detection sensor 4 can sense the sensed part 5; when the second driving source 7 drives the second movable blade 3 to move forward to a certain trimming point within the trimming point range through the second driving component, the detection sensor 4 cannot sense the sensed part 5 at the moment; therefore, in the process that the second driving source 7 drives the second movable blade 3 to move forward through the second driving assembly, but the second movable blade 3 does not move to the trimming point, the detection sensor 4 can sense the sensed part 5. Meanwhile, the installation position of the detection sensor 4 should ensure that the second movable knife 3 happens to move forward to the thread cutting point when the output signal of the detection sensor 4 changes. In addition, in the embodiment, the first movable knife 2 and the second movable knife 3 are movably arranged on the lower end surface of the main needle plate 1; in the up-down direction, the first blade 21 on the first movable blade 2, the second blade 31 on the second movable blade 3, and the small needle plate 17 are sequentially arranged from bottom to top.

As shown in fig. 8, the double-knife thread trimming device of the sewing machine based on the structure of the present application, which uses the double-knife thread trimming device of the sewing machine, comprises the following steps:

s1, in an initial state and when no thread is cut, the first movable knife 2 and the second movable knife 3 are located at respective initial positions, and the detection sensor 4 can sense the sensed part 5;

s2, when the thread needs to be cut after the sewing is finished, the electric control module sends an instruction to the first driving source 6, and the first driving source 6 starts to move forwards; the first driving source 6 drives the first movable knife 2 to move forwards through the first driving component until the first movable knife 2 moves forwards to a first limit position, and in the process, the first movable knife 2 completes wire splitting action and the first knife edge 21 forwards crosses a wire cutting point;

s3, in the process that the first movable blade 2 performs the wire dividing action or after the wire dividing action is finished, the electric control module sends an instruction to the second driving source 7, and the second driving source 7 starts to move forwards; the second driving source 7 drives the second movable blade 3 to move forwards through a second driving component; when the detection sensor 4 does not sense the sensed part 5, the electric control module controls the second driving source 7 to stop acting according to the change of the output signal of the detection sensor 4, and at the moment, the second movable knife 3 moves forwards to a second limit position and is positioned at a thread cutting point;

s4, the electronic control module sends the instruction to the first driving source 6 again, and the first driving source 6 starts to move reversely; the first driving source 6 drives the first movable blade 2 to perform return motion through the first driving component until the first movable blade 2 moves to the initial position in the return motion; in the process of the return motion of the first movable knife 2, the first blade 21 on the first movable knife 2 is engaged with the second blade 31 on the second movable knife 3 at the thread cutting point, as shown in fig. 7, and then the suture hooked by the first movable knife 2 is cut at the thread cutting point;

s5, the electronic control module sends the instruction to the second driving source 7 again, and the second driving source 7 starts to move reversely; the second driving source 7 drives the second movable blade 3 to perform a return movement through the second driving assembly until the second movable blade 3 moves back to its initial position.

From the above, it can be seen that: the application decomposes the thread cutting action into a plurality of time sequence actions, realizes the control of the time sequence actions of the first movable knife 2 and the second movable knife 3 by controlling the actions of the first driving source 6 and the second driving source 7 through the electric control module, combines the mutual cooperation of the detection sensor 4 and the sensed part 5, so that the electronic control module accurately controls the time point of the second driving source 7 stopping when the second movable blade 3 advances according to the change of the output signal of the detection sensor 4, therefore, the second limit position of the advancing of the second movable knife 3 is accurately controlled, namely the second movable knife 3 is accurately controlled to stop at the trimming point (namely the center of the needle falling hole 171 on the small needle plate 17 or the position near the center of the needle falling hole 171), the first knife edge 21 on the first movable knife 2 and the second knife edge 31 on the second movable knife 3 are ensured to be meshed at the set trimming point, the accurate control of the ideal trimming position is realized, and the trimming effect of the stub is stably realized. In addition, the first movable knife 2 and the second movable knife 3 are respectively driven by the first driving source 6 and the second driving source 7, so that the movement between the first movable knife 2 and the second movable knife 3 is not linked and independent, the movement between the first movable knife 2 and the second movable knife 3 is convenient to realize a certain time sequence, the whole double-movable-knife thread shearing device of the sewing machine is easy to realize, and the double-movable-knife thread shearing device has better operability and controllability.

Further, in the double-knife thread trimming device of the sewing machine according to the present application, the second limit position of the second moving knife 3 when moving forward, that is, the position of the thread trimming point, can be adjusted by adjusting the mounting position of the detection sensor 4. Based on this, along the direction of motion of second moving sword 3, the mounted position of detection sensor 4 on the sewing machine casing is adjustable, and preferred structure is: as shown in fig. 2 and 3, the double-knife thread trimmer of the sewing machine further includes a sensor mounting plate 8 having a mounting adjustment groove 81, the mounting adjustment groove 81 is a kidney-shaped groove and the extending direction of the mounting adjustment groove is the same as the moving direction of the second moving knife 3, the sensor mounting plate 8 is fixed to the housing of the sewing machine by a fixing screw, the fixing screw is inserted into the mounting adjustment groove 81, and the detection sensor 4 is fixed to the sensor mounting plate 8. Taking the view angle shown in fig. 4 as an example, when the upper side of the paper surface in the view of fig. 4 is defined as the front direction and the lower side of the paper surface is defined as the left direction, the second moving blade 3 moves in the front-rear direction, so that the mounting adjustment groove 81 on the sensor mounting plate 8 extends forward and backward; after the fixing screws are unscrewed, the front and rear mounting positions of the sensor mounting plate 8 on the sewing machine shell can be adjusted, and the fixing screws are screwed after the adjustment is finished, so that the adjustment is convenient, accurate and quick. Preferably, in this embodiment, the detecting sensor 4 is a photoelectric sensor, and the sensed member 5 is a photosensitive sheet.

Further, the first moving blade 2 and the second moving blade 3 can move linearly or swing; in this embodiment, the first moving blade 2 and the second moving blade 3 both move in a swinging manner. As shown in fig. 1 to 4, the first movable blade 2 is rotatably mounted to the main needle plate 1 by a first axial screw 18 extending vertically, the first movable blade 2 can swing around the first axial screw 18, and the first axial screw 18 forms a fixed swing fulcrum of the first movable blade 2. The second movable knife 3 is rotatably mounted on the main needle plate 1 through a second axial screw 19 extending up and down, the second movable knife 3 can swing around the second axial screw 19, and the second axial screw 19 forms a fixed swing fulcrum of the second movable knife 3. The second blade 31 is arranged at one end of the second movable blade 3, the sensed piece 5 is fixed at the other end of the second movable blade 3, and the second axial screw 19 is positioned between the second blade 31 and the sensed piece 5. In addition, the first driving source 6 and the second driving source 7 are both installed in the sewing machine housing, and the first driving source 6 and the second driving source 7 can be selected from a motor, an electromagnet, an air cylinder, and the like, and in this embodiment, the first driving source 6 and the second driving source 7 are both motors, so that the first driving source 6 has a rotatable first driving portion 61, and the second driving source 7 has a rotatable second driving portion 71. Specifically, the second motor is a linear screw stepping motor, and the second driving portion 71 is a driving screw of the linear screw stepping motor.

As shown in fig. 1 to 4, the first driving assembly connected between the first driving source 6 and the first moving blade 2 preferably has a structure in which: the first driving assembly comprises a rotary driving frame 9, a first connecting rod 10, a second connecting rod 11, a trimming cam 12 fixed on the first driving part 61, a connecting plate 13 and a connecting pull rod 14; the connecting plate 13 is rotatably arranged on the sewing machine shell through a third axial screw 20, the connecting plate 13 can swing around the third axial screw 20, and the third axial screw 20 forms a fixed swing fulcrum of the connecting plate 13; the upper end of the connecting plate 13 is hinged with the trimming cam 12, and the hinged point of the connecting plate and the trimming cam is eccentric to the first driving part 61; the lower end of the connecting plate 13 is hinged with one end of a connecting pull rod 14, and one end of the connecting pull rod 14 is hinged with the rotary driving frame 9; the rotary driving frame 9 and the first connecting rod 10 are rotatably arranged on the main needle plate 1 through a fourth axial screw 21 extending up and down, so that the rotary driving frame 9 and the first connecting rod 10 can swing around the fourth axial screw 21 and are coaxially hinged to the main needle plate 1; the driving frame 9 and the first connecting rod 10 are simultaneously fixed through a locking screw 22 extending up and down, and two ends of the second connecting rod 11 are respectively hinged with the first connecting rod 10 and the first movable blade 2. When the electric control module controls the first driving source 6 to act, the first driving portion 61 of the first driving source 6 drives the trimming cam 12 to synchronously rotate, the driving connecting plate 13 swings around the third axial screw 20, the rotating driving frame 9 and the first connecting rod 10 both swing around the fourth axial screw 21 through the connecting pull rod 14, and the first connecting rod 10 drives the first movable knife 2 to swing around the first axial screw 18 through the second connecting rod 11. In the view shown in fig. 4, when the first driving source 6 drives the first movable blade 2 to move forward through the first driving assembly, the first movable blade 2 swings counterclockwise around the first axial screw 18, and the first blade 21 swings forward; when the first driving source 6 drives the first movable blade 2 to move back through the first driving assembly, the first movable blade 2 swings clockwise around the first axial screw 18, and the first blade 21 swings backwards. Preferably, the rotation driving frame 9 is provided with a waist-shaped locking adjustment groove 91, the locking screw 22 for fixing the rotation driving frame 9 and the first connecting rod 10 is inserted into the locking adjustment groove 91, and the fixing position of the first connecting rod 10 fixed to the rotation driving frame 9 can be adjusted by the locking screw 22 and the locking adjustment groove 91, so as to adjust the initial position of the second connecting rod 11, and thus adjust the movement amplitude of the first movable blade 2.

As shown in fig. 2 to 4, the preferred structure of the second driving assembly connected between the second driving source 7 and the second moving blade 3 is: the second driving assembly comprises a universal joint 15 and a third connecting rod 16, a threaded hole is formed in the end portion of the second driving portion 71, the universal joint 15 is an axial ball joint universal joint, one end of the universal joint 15 is a ball joint 151 with a screw portion, the other end of the universal joint is a ball groove joint 152 with a threaded hole, one end of the third connecting rod 16 is provided with a screw portion, the screw portion of the ball joint 151 is in threaded connection with the threaded hole of the second driving portion 71, the screw portion of the third connecting rod 16 is in threaded connection with the threaded hole of the ball groove joint 152, and the other end of the third connecting rod 16 is hinged to the second movable blade 3. When the electronic control module controls the second driving source 7 to act, the second driving portion 71 of the second driving source 7 rotates, the second driving portion 71 is in threaded fit with the ball joint 151, and the position of the second driving portion 71 remains fixed, so that the second driving portion 71 can drive the ball joint 151 to move along the second driving portion 71 while rotating, the universal joint 15 is driven to move, the universal joint 15 drives the third connecting rod 16 to move together, and the second movable blade 3 is driven to swing around the second axial screw 19. In the view shown in fig. 4, when the second driving source 7 drives the second movable blade 3 to move forward through the second driving assembly, the second movable blade 3 swings clockwise around the second axial screw 19, the second blade 31 swings forward, and the sensed part 5 swings backward; when the second driving source 7 drives the second movable blade 3 to move back through the second driving assembly, the second movable blade 3 swings anticlockwise around the second axial screw 19, the second blade 31 swings backwards, and the sensed part 5 swings forwards.

The first moving knife 2 is used for separating, hooking and shearing lines; therefore, as shown in fig. 5, the first moving blade 2 includes a line dividing portion 22 and a line hooking portion 23 which are oppositely arranged in the front-back direction along the moving direction of the first moving blade 2, and a line sliding portion 24 connected between the line dividing portion 22 and the line hooking portion 23, the first blade 21, the line dividing portion 22, the line hooking portion 23 and the line sliding portion 24 are all located on the same side of the first axial screw 18, the line dividing portion 22 is a concave arc section, the line hooking portion 23 is a concave arc section, the line sliding portion 24 is a convex arc section, the connection of the line dividing portion 22 and the line sliding portion 24, and the connection of the line hooking portion 23 and the line sliding portion 24 are all formed with a tip, and the first blade 21 is adjacent to the intersection of the line dividing portion 22 and the line sliding portion 24. Preferably, the upper end surface of the first movable blade 2 facing the second movable blade 3 is provided with a line accommodating groove 25, one end of the line accommodating groove 25 extends to the second blade 31, and the other end extends to the line hooking part 23.

For the control of the electronic control module on the second driving source 7, as shown in fig. 8, an initial default origin of the second driving portion 71 of the second driving source 7 is preset in the electronic control module; when the second driving source 7 is powered on, the electronic control module sends an instruction to the second driving source 7, the second driving portion 71 rotates by an initial angle, the second driving portion 71 rotates to an initial default origin, so that the initial position of the second movable blade 3 is controlled, and then the forward movement of the second movable blade 3 is executed.

As shown in fig. 8, the double-blade thread cutting method of the sewing machine using the double-blade thread cutting device of the sewing machine having the above-described structure specifically includes the steps of:

step 1, when the double-knife thread shearing device of the sewing machine is in an initial state, a first driving source 6 and a second driving source 7 are powered on, an electric control module controls a second driving part 71 to rotate by an initial angle until the second driving part 71 is located at an initial default original point, at the moment, as shown in fig. 4, a first movable knife 2 and a second movable knife 3 are located at respective initial positions, at the moment, a first cutting edge 21 on the first movable knife 2 and a second cutting edge 31 on the second movable knife 3 are both far away from the center of a needle falling hole 171, the first cutting edge 21 and the second cutting edge 31 are not meshed, and the first cutting edge 21 is far away from the center of the needle falling hole 171 compared with the second cutting edge 31; meanwhile, the detection sensor 4 can sense the sensed member 5.

Step 2, after the last stitch of the sewing machine is sewn, the needle is back-stitched, the electronic control module sends an instruction to the first driving source 6, the first driving source 6 starts to move in the forward direction, the rotary driving frame 9 rotates clockwise by an angle through the thread trimming cam 12, the connecting plate 13 and the connecting pull rod 14, the rotary driving frame 9 drives the first movable knife 2 to rotate counterclockwise by an angle through the first connecting rod 10 and the second connecting rod 11, and then the first movable knife 2 moves forward to a first limit position; in this process, the first blade 21, the splitting portion 22 and the sliding portion 24 of the first moving blade 2 swing forward, the splitting portion 22 of the first moving blade 2 completes the splitting operation, the suture which is not required to be cut is separated by the splitting portion 22 and swings forward along with the splitting portion 22, the suture which is required to be cut slides into the hooking portion 23 along the sliding portion 24, and meanwhile, the first blade 21 of the first moving blade 2 moves forward to cross the set thread cutting point.

Step 3, in the process that the first movable blade 2 executes the wire splitting action (the wire splitting action is not influenced) or after the wire splitting action is finished, the electronic control module sends an instruction to the second driving source 7, the second driving source 7 starts to move in the forward direction, the second movable blade 3 is driven to rotate clockwise through the universal joint 15 and the third connecting rod 16, the second blade 31 moves forward, the sensed part 5 moves backward, and when the sensed part 5 cannot be sensed by the detection sensor 4, the electronic control module controls the second driving source 7 to stop moving according to the change of a feedback signal of the detection sensor 4; at this time, the second movable blade 3 advances to the second limit position, the second blade 31 is located at the set trimming point, that is, at the center of the needle dropping hole 171 or near the center of the needle dropping hole 171, and the counter-clockwise rotation angle of the second movable blade 3 is defined by the cooperation of the detection sensor 4 and the sensed piece 5, and the magnitude of the counter-clockwise rotation angle is determined by the installation position of the detection sensor 4 in the front-back direction.

Step 4, the electronic control module sends an instruction to the first driving source 6 again, the first driving source 6 starts to move reversely, the rotary driving frame 9 rotates anticlockwise for an angle through the trimming cam 12, the connecting plate 13 and the connecting pull rod 14, the rotary driving frame 9 drives the first movable knife 2 to rotate clockwise for an angle through the first connecting rod 10 and the second connecting rod 11, and then the first movable knife 2 returns to the initial position; in the process of the return motion of the first movable blade 2, the first blade 21, the thread dividing portion 22 and the thread sliding portion 24 on the first movable blade 2 swing backwards, the thread sliding into the thread hooking portion 23 is drawn into the thread accommodating groove 25 on the upper end surface of the first movable blade 2, when the first blade 21 on the first movable blade 2 moves backwards to a thread shearing point, the first blade 21 is engaged with the second blade 31, and as shown in fig. 7, the thread hooked by the first movable blade 2 is sheared at the thread shearing point, so that thread shearing is realized. Thus, it can be seen that: the position of the trimming point is determined by the second limit position of the advancing second movable blade 3 and the mounting position of the detection sensor 4 in the front-back direction, and the second limit position of the advancing second movable blade 3 can be accurately adjusted by adjusting the front-back mounting position of the detection sensor 4, so that the position of the trimming point is accurately adjusted.

And 5, in the return stroke process of the first movable blade 2 after the first blade 21 passes through the second blade 31 backwards or after the first movable blade 2 returns to the initial position, the electronic control module sends an instruction to the second driving source 7 again, the second driving source 7 starts to move reversely, the second movable blade 3 is driven to rotate anticlockwise through the universal joint 15 and the third connecting rod 16 until the second driving part 71 rotates to the initial default original point, and at the moment, the second movable blade 3 moves to the initial position in the return stroke. And at this moment, finishing the thread trimming action and waiting for the next thread trimming command. The initial position of the second moving blade 3 is determined by the initial default original point of the second driving part 71, and the initial default original point of the second driving part 71 of the second driving source 7 is set or adjusted in the electric control module, so that the initial position of the second moving blade 3 can be set or adjusted, and the adjustment is accurate and convenient; the adjusting range of the initial position of the second movable knife 3 is related to the actual position of the second movable knife 3, so that the knife is not collided and a certain margin is left, and therefore, the return limit position of the second movable knife 3 can be protected by setting the adjusting range of the initial position of the second movable knife 3.

Further, the form of the command sent by the electronic control module to the first driving source 6 and the second driving source 7 is pulse, the positive and negative properties of the pulse determine the positive rotation or the negative rotation of the first driving portion 61 and the second driving portion 71, and the number of the pulse determines the rotation angle of the first driving portion 61 and the second driving portion 71, that is, the forward stroke and the return stroke of the first moving blade 2 and the forward stroke and the return stroke of the second moving blade 3. In order to control the limit forward stroke of the second moving blade 3 during forward movement, the following two schemes are adopted in the present application. Scheme one, electric control protection; as shown in fig. 8, the sewing machine is provided with an alarm module connected with the electronic control module; the electric control module is prestored with a maximum pulse number X, and the maximum pulse number X is matched with the allowed maximum forward stroke of the second movable knife 3; in step S3, before the second driving source 7 drives the second moving blade 3 to move at the trimming point through the second driving assembly, the electronic control module obtains the real-time pulse number Y sent to the second driving source 7, wherein the real-time pulse number Y is matched with the real-time forward stroke of the second moving blade 3; if the electronic control module judges that the real-time pulse number Y is larger than or equal to the maximum pulse number X, the electronic control module reports a mistake and does not send a pulse to the second driving source 7, namely the electronic control module controls the second driving source 7 to stop acting and triggers the alarm module, otherwise, the electronic control module works normally, so that the limit advancing stroke of the second movable knife 3 is controlled, the knife collision protection is realized, and an operator can adjust the front and back positions of the detection sensor 4 according to the alarm information of the alarm module so as to accurately adjust the second limit position when the second movable knife 3 advances. Scheme two, limiting pin protection; two limit pins are arranged on the main needle plate 1, and the two limit pins are respectively arranged at the forward limit position and the return limit position allowed by the second movable knife 3 along the motion path of the second movable knife 3; when the second movable blade 3 advances, the limiting pin arranged at the advancing limit position is abutted against the second movable blade 3 to limit the second movable blade 3 to continue to advance; when the second movable blade 3 returns, the limit pin arranged at the return limit position is abutted against the second movable blade 3, and then the second movable blade 3 is limited to continue returning. The two schemes can be configured simultaneously, or one of the two schemes can be selected.

In addition, when the electronic control module controls the second driving source 7, the electronic control module can calculate the time required by the second moving blade 3 to finish the forward stroke according to the feedback signal from the sent instruction signal to the receiving detection sensor 4, and then the electronic control module adjusts the frequency of the instruction pulse sent to the second driving source 7 according to actual needs, so that the rotating speed of the motor forming the second driving source 7 is accurately adjusted, and the adjustment of the time required by the second moving blade 3 to finish the forward stroke is realized; the time required for the second moving blade 3 to complete the return stroke can also be realized by adjusting the frequency of the command pulse sent to the second driving source 7; so that the speed of the second movable knife 3 swinging around the second axial screw 19 has strong adjustability.

In conclusion, the double-movable-cutter thread cutting device of the sewing machine, which is provided by the application, has the advantages of simple overall structure, low cost, small occupied space, strong adjustability in multiple aspects, high adjustment precision and stability. 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 and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The utility model provides a double acting sword thread trimmer devices of sewing machine, moves sword (3) including all movably installing in first moving sword (2) and the second of main faller (1), first cutting edge (21) and the second on the second moves sword (3) on first moving sword (2) can interlock its characterized in that: still include electronic control module, install in detection sensor (4) of sewing machine casing, be fixed in the second and move sword (3) and can be detected by response piece (5), first driving source (6), second driving source (7), first drive assembly and the second drive assembly that sensor (4) sensed, first driving source (6) link to each other with first sword (2) that move through first drive assembly, drive first sword (2) motion, second driving source (7) move sword (3) through second drive assembly and second and link to each other, drive second and move sword (3) motion, detection sensor (4), first driving source (6) and second driving source (7) all link to each other with electronic control module.

2. Double-knife thread trimming apparatus for sewing machines according to claim 1, characterized in that: still including sensor mounting panel (8) of seting up installation adjustment tank (81), installation adjustment tank (81) are a kidney slot, and the direction of extension moves the direction of motion unanimity of sword (3) with the second, sensor mounting panel (8) are fixed in the sewing machine casing through set screw, set screw wears to establish in installation adjustment tank (81), detect sensor (4) and be fixed in sensor mounting panel (8).

3. Double-knife thread trimming apparatus for sewing machines according to claim 1, characterized in that: the detection sensor (4) is a photoelectric sensor, and the sensed piece (5) is a photosensitive piece.

4. Double-knife thread trimming apparatus for sewing machines according to claim 1, characterized in that: the first drive source (6) and the second drive source (7) are both motors.

5. Double-knife thread-cutting device of sewing machine according to claim 1 or 4, characterized in that: the first movable knife (2) is rotatably arranged on the main needle plate (1); first drive assembly is including rotating driving frame (9), first connecting rod (10) and second connecting rod (11), it rotationally installs in main faller (1) to rotate driving frame (9) and first connecting rod (10) coaxial line, it is fixed mutually that rotation driving frame (9) are driven the swing, just rotate driving frame (9) and first connecting rod (10) by first driving source (6), the both ends of second connecting rod (11) are articulated with first connecting rod (10) and first sword (2) respectively.

6. Double-knife thread trimming apparatus for sewing machines according to claim 5, characterized in that: the first drive source (6) has a rotatable first drive section (61); the first driving assembly further comprises a trimming cam (12) fixed on the first driving portion (61), a connecting plate (13) rotatably installed on the shell of the sewing machine and a connecting pull rod (14), two ends of the connecting plate (13) are hinged to one ends of the trimming cam (12) and the connecting pull rod (14) respectively, and one end of the connecting pull rod (14) is hinged to the rotating driving frame (9).

7. Double-knife thread-cutting device of sewing machine according to claim 1 or 4, characterized in that: the second movable knife (3) is rotatably arranged on the main needle plate (1), the second driving source (7) is provided with a rotatable second driving part (71), and a threaded hole is formed in the end part of the second driving part (71); the second drive assembly includes universal joint (15) and third connecting rod (16), ball joint (151), the ball groove joint (152) of the other end for having the screw hole of universal joint (15) one end, the one end of third connecting rod (16) has the screw part, the screw part of ball joint (151) and the screw hole threaded connection of second drive portion (71), the screw part of third connecting rod (16) and the screw hole threaded connection of ball groove joint (152), the other end and the second of third connecting rod (16) move sword (3) articulated.

8. Double-knife thread trimming apparatus for sewing machines according to claim 1, characterized in that: first move sword (2) including the part of dividing (22) and the part of colluding (23) that set up relatively and connect slide-wire portion (24) between part of dividing (22) and the part of colluding (23), first cutting edge (21) are close to in the crossing department of part of dividing (22) and slide-wire portion (24), first move sword (2) and seted up on the up end towards second move sword (3) and hold wire casing (25), the one end that holds wire casing (25) extends to second cutting edge (31) department, the other end extends to the part of colluding (23).