CN117904802A - Feeding thread cutting mechanism based on long connecting rod short crank structure and sewing machine - Google Patents

Abstract

The application provides a feeding thread cutting mechanism and a sewing machine based on a long connecting rod short crank structure, wherein the feeding thread cutting mechanism comprises a feeding thread cutting driving source, a feeding mechanism and a thread cutting mechanism; the feeding mechanism comprises a tooth frame, feeding teeth, a driving crank driven by a feeding wire cutting driving source to rotate, a feeding arm extending from the driving crank, a feeding connecting rod, a feeding shaft capable of rotating around the axis of the feeding shaft, a feeding crank fixed at one end of the feeding shaft and a tooth frame seat fixed at the other end of the feeding shaft, wherein two ends of the feeding connecting rod are respectively connected with the feeding arm and the feeding crank in a rotating way, the tooth frame seat is connected with a feeding connecting part of the tooth frame, and the effective length of the feeding arm is smaller than that of the feeding connecting rod. In the application, the power of the dental articulator in the feeding mechanism is derived from the feeding wire cutting driving source, the transmission chain between the dental articulator and the feeding wire cutting driving source is shorter, the whole structure is simplified, and the stability is good; the device occupies small space, and avoids interference to the layout and installation of other functional mechanisms in the sewing machine.

Description

Feeding thread cutting mechanism based on long connecting rod short crank structure and sewing machine

Technical Field

The invention relates to the technical field of sewing machines, in particular to a feeding thread cutting mechanism based on a long connecting rod short crank structure and a sewing machine comprising the same.

Background

At present, each large sewing machine company has own design platform, and a feeding mechanism, a feed lifting mechanism, a thread trimming mechanism and a presser foot lifting mechanism are important functional mechanisms of the sewing machine, once the design platform of a certain company is determined, the research and development of products and next generation products are iterative update based on the design platform, and the research and development of another brand new design platform can be hardly performed.

Such as: the driving mechanism of the lockstitch sewing machine disclosed in China patent application number 201220297729.6 drives a feed lifting shaft and a feed feeding shaft to rotate through a main shaft (namely an upper shaft), the main shaft is driven to rotate by a main motor, the feed lifting shaft drives a feed lifting assembly to reciprocate up and down through a set of feed lifting assembly to drive a feed lifting assembly and feed feeding teeth to reciprocate back and forth to execute feed lifting action, and meanwhile, the main shaft drives a lower shaft to rotate through a set of synchronous belt pulley mechanism to drive a rotating shuttle mechanism to rotate to execute thread hooking action. Further, the sewing machine may be further provided with a thread cutting mechanism, such as an automatic thread cutting mechanism disclosed in chinese patent application No. 201710215982.X, wherein when thread cutting is required, the thread cutting driving source acts, so that the thread cutting ball contacts with the thread cutting cam fixed on the lower shaft, and then the thread cutting assembly is driven to operate by rotation of the lower shaft to perform automatic thread cutting. Obviously, the structure of the feeding mechanism, the lifting tooth mechanism and the thread cutting mechanism in the sewing machine with the structure is complex, the number of parts is large, the transmission chain is long, and the thread cutting mechanism is provided with the clutch assembly to realize thread cutting action.

And, for example: the invention patent of China with the application number 201210365288.3 discloses a sewing machine, a feed lifting mechanism is driven by a main shaft in the sewing machine, the main shaft is driven by a main motor to rotate, a feeding mechanism is driven by a feeding motor, and the clutch of a thread cutting mechanism is driven by the feeding motor; when cutting the wire, after the transmission part in the feeding motor driving wire cutting mechanism is combined, the wire cutting cam on the lower shaft still drives the wire cutting assembly to operate so as to execute automatic wire cutting action. Obviously, the structure of the sewing machine is complex, particularly, a grooved cam structure is used, the grooved cam structure is difficult to implement, and the grooved cam structure still needs to rely on a main motor to drive a main shaft to rotate, the main shaft to drive a lower shaft to rotate and the lower shaft to drive a thread cutting cam to rotate when a thread is cut, so that the thread cutting action is completed.

For another example: a thread cutting and presser foot lifting device of a sewing machine is disclosed in China patent application number 201520782770.6, and a stepping motor performs thread cutting driving and presser foot lifting driving through a set of complex mechanisms. However, as the final execution end (namely the movable knife and the fixed knife) in the thread cutting mechanism is arranged at the left end of the bottom plate, and the final execution end (namely the presser foot) in the presser foot lifting mechanism is arranged at the machine head, the span between the stepping motor and the movable knife and between the stepping motor and the presser foot is large, so that the whole transmission chain of the sewing machine is longer, the stepping motor and the transmission structure occupy most of the installation space in the bottom plate, and certain interference is caused to the arrangement and the installation of other transmission structures in the sewing machine.

And, for example: the utility model patent of China with the application number 202120273965.3 discloses a sewing machine with a positioning feed dog stop position, which drives a swinging seat to rotate through a stepping motor, so that the swinging seat is positioned at different position angles, and the different position angles of the swinging seat correspond to different needle pitches; meanwhile, the stepping motor drives a thread cutting assembly such as a thread cutting fork wheel to operate through a thread cutting crank wheel, and executes thread cutting action. However, the sewing machine has the advantages of a large number of parts, long transmission chain, poor structural stability, quite complex transmission such as needle pitch adjustment and thread cutting driving, and the like, and simultaneously, the structure also uses a groove-shaped cam structure with great implementation difficulty.

In summary, the existing sewing machine has the following problems: 1. the structure is complex, so that the stability is poor, and the implementation difficulty is high; 2. the transmission chain is long, so that a transmission structure comprising a stepping motor occupies most of the installation space of the machine, and the arrangement and the installation of other structures are interfered; 3. the function is single, the power of the thread cutting mechanism still depends on the main shaft or depends on the main motor, and the power source arranged in the thread cutting mechanism can only realize the switching of thread cutting clutch.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a feeding wire cutting mechanism based on a long link short crank structure, which can shorten the transmission chain of the feeding transmission part and simplify the structure thereof.

In order to achieve the above purpose, the invention provides a feeding thread cutting mechanism based on a long connecting rod short crank structure, which comprises a feeding thread cutting driving source, a feeding mechanism and a thread cutting mechanism;

The feeding mechanism comprises a tooth frame, feeding teeth fixed on the tooth frame, a driving crank driven by a feeding wire cutting driving source to rotate, a feeding arm extending from the driving crank, a feeding connecting rod, a feeding shaft capable of rotating around the axis of the feeding arm, a feeding crank fixed at one end of the feeding shaft and a tooth frame seat fixed at the other end of the feeding shaft, wherein one end of the tooth frame is provided with a feeding connecting part, two ends of the feeding connecting rod are respectively connected with the feeding arm and the feeding crank in a rotating way, the tooth frame seat is connected with the feeding connecting part of the tooth frame, and the effective length of the feeding arm is smaller than that of the feeding connecting rod;

the wire cutting mechanism comprises a movable moving blade and a wire cutting transmission unit which is in transmission connection between a feeding wire cutting driving source and the moving blade.

Further, the feeding wire cutting driving source is a driving motor, and the driving crank is fixed on a motor shaft of the driving motor.

Further, the feeding thread cutting mechanism further comprises an integrated mounting base, the feeding thread cutting driving source is independent of other driving sources in the sewing machine, and the feeding thread cutting driving source, the feeding mechanism and the thread cutting mechanism are all mounted on the integrated mounting base.

Further, the integrated mounting base has a feed support portion in which the feed shaft is rotatably supported, and the feed crank and the dental frame mount are distributed in an axial direction of the feed shaft.

Further, when the feeding arm is collinear with the feeding connecting rod, the angle of the feeding arm isWhen the angle of the feeding arm is at/>Within this range, the feed thread cutting mechanism makes the sewing machine have a small stitch length.

Further, when the angle of the feeding arm is atWithin this range, the feed thread cutting mechanism makes the movement amount of the feed dog (22) in the front-rear direction not more than 1mm.

Further, when the feeding arm is collinear with the feeding connecting rod, the feeding tooth is located at a front limit position or a rear limit position in the front-rear reciprocating movement range of the feeding tooth.

The application also provides a sewing machine, wherein the feeding thread cutting mechanism is arranged in the sewing machine.

Further, the sewing machine further comprises a lifting tooth driving source and a lifting tooth mechanism, a lifting tooth connecting part is arranged at the other end of the tooth frame, and the lifting tooth mechanism is in transmission connection between the lifting tooth driving source and the lifting tooth connecting part of the tooth frame.

Further, the lifting tooth driving source is a main motor of the sewing machine, and the lifting tooth mechanism comprises a main shaft driven by the main motor to rotate, a lifting tooth shaft parallel to the main shaft, a first lifting tooth transmission assembly connected between the main shaft and the lifting tooth shaft, and a second lifting tooth transmission assembly connected between the lifting tooth shaft and a lifting tooth connecting part of the tooth frame.

Further, the first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel fixed on the main shaft, a lifting tooth crank fixed at one end of the lifting tooth shaft and a lifting tooth connecting rod, one end of the lifting tooth connecting rod is rotatably sleeved on the periphery of the lifting tooth eccentric wheel, and the other end of the lifting tooth connecting rod is hinged with the lifting tooth crank; the second lifting tooth transmission assembly comprises a lifting tooth fork-shaped crank fixed at the other end of the lifting tooth shaft and a lifting tooth sliding block hinged with the lifting tooth connecting part of the tooth frame, and a lifting tooth sliding groove in sliding fit with the lifting tooth sliding block is formed in the lifting tooth fork-shaped crank.

Further, the first lifting tooth transmission assembly comprises a driving belt pulley fixed on the main shaft, a driven belt pulley fixed at one end of the lifting tooth shaft, and a transmission belt connected to the peripheries of the driving belt pulley and the driven belt pulley; the second lifting tooth transmission assembly comprises a lifting tooth eccentric wheel and a lifting tooth connecting rod, the lifting tooth eccentric wheel is fixed at the other end of the lifting tooth shaft, one end of the lifting tooth connecting rod is rotatably sleeved on the periphery of the lifting tooth eccentric wheel, and the other end of the lifting tooth connecting rod is hinged with the lifting tooth connecting part of the tooth frame.

As described above, the feeding thread cutting mechanism and the sewing machine based on the long connecting rod short crank structure provided by the invention have the following beneficial effects:

In the application, the power of the dental articulator in the feeding mechanism is derived from the feeding wire cutting driving source, the transmission chain between the dental articulator and the feeding wire cutting driving source is shorter, and the whole structure is very compact and simplified, thereby improving the stability and being convenient for implementation; meanwhile, the space occupation is small, and interference to the layout and installation of other functional mechanisms in the sewing machine is avoided.

Drawings

Fig. 1 is a schematic structural view of a feeding and trimming mechanism in the application.

Fig. 2 is an exploded view of fig. 1, omitting the integrated mounting base.

Fig. 3 is a left side view of fig. 1, omitting the integrated mounting base.

Fig. 4 is a schematic distribution diagram of a working area of a feeding arm in the feeding and trimming mechanism.

Fig. 5 is a schematic diagram of a wire cutting clutch assembly in a separated state in a feeding wire cutting mechanism.

Fig. 6 is a schematic view of the wire cutting clutch assembly in an engaged state in the feed wire cutting mechanism.

Fig. 7a to 7d are schematic diagrams of four movement tracks of the feeding teeth in the feeding wire cutting mechanism.

Fig. 8 is a schematic diagram of the position of the feeding arm and the feeding link in the feeding and trimming mechanism when the feeding arm and the feeding link are collinear.

Fig. 9a to 9c are three distribution diagrams of the wire cutting working area of the feeding arm in the feeding wire cutting mechanism.

FIG. 10 is a schematic view of the distribution position in the sewing machine in the feed scissor mechanism of the application.

FIG. 11 is a schematic view showing a structure of a first embodiment of the sewing machine according to the present application.

FIG. 12 is a schematic view of a sewing machine according to a second embodiment of the present application.

Description of element reference numerals

10. Feeding and wire cutting driving source

11. Driving motor

20. Feeding mechanism

21. Tooth rack

211. Feeding connecting part

212. Lifting tooth connecting part

22. Feeding tooth

23. Driving crank

231. Feeding arm

232. Wire cutting arm

24. Feeding connecting rod

25. Feeding shaft

26. Feeding crank

27. Dental frame base

30. Thread cutting mechanism

31. Movable knife

32. Shearing shaft

33. Thread cutting ball

34. Wire cutting driving piece

341. Wire cutting driving arm

342. Reset arm

35. Fixed knife

36. Wire cutting crank

37. Wire cutting connecting rod

38. Movable knife rest

39. Reset torsion spring

40. Integrated mounting base

41. Mounting main board

42. Motor mounting plate

43. Feeding support part

44. Wire cutting support part

50. Tooth lifting mechanism

51. Main shaft

52. Lifting shaft

53. Lifting tooth eccentric wheel

54. Lifting tooth crank

55. Lifting tooth connecting rod

56. Fork-shaped crank for lifting tooth

57. Lifting tooth sliding block

58. Driving belt wheel

59. Driven belt pulley

510. Transmission belt

60. Bottom plate

Detailed Description

Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, 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 invention to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the invention, are included in the spirit and scope of the invention which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used herein for descriptive purposes only and not for purposes of limitation, and are intended to limit the scope of the invention as defined by the claims and the relative terms thereof as construed as corresponding to the claims.

The application relates to a feeding thread cutting mechanism based on a long connecting rod short crank structure and a sewing machine comprising the same. For convenience of description, in the following embodiments, the following directions are defined as follows: the longitudinal direction of the sewing machine is defined as the left-right direction, the direction toward the head of the sewing machine is the left direction, and the direction toward the tail of the sewing machine is the right direction, and the left-right direction is the axial direction of the main shaft 51 in the sewing machine; the height direction of the sewing machine is defined as the up-down direction, the width direction of the sewing machine is defined as the front-back direction, and the moving direction of the sewing material is defined as the front direction when the sewing machine is forward sewing.

As shown in fig. 1 to 3, the feeding and trimming mechanism based on the long-link short-crank structure according to the present application includes a feeding and trimming driving source 10, a feeding mechanism 20 and a trimming mechanism 30; the feeding mechanism 20 comprises a tooth frame 21, a feeding tooth 22 fixed on the upper end surface of the tooth frame 21, a driving crank 23 driven to rotate by a feeding wire cutting driving source 10, a feeding arm 231 extending from the driving crank 23, a feeding connecting rod 24, a feeding shaft 25 capable of rotating around the axis of the feeding arm and extending leftwards and rightwards axially, a feeding crank 26 fixed on the right end of the feeding shaft 25, and a tooth frame seat 27 fixed on the left end of the feeding shaft 25, wherein the front end of the tooth frame 21 is a feeding connecting part 211, the rear end of the tooth frame 21 is a lifting tooth connecting part 212, two ends of the feeding connecting rod 24 are respectively connected with the feeding arm 231 and the feeding crank 26 in a rotating way, namely hinged, the tooth frame seat 27 is connected with the feeding connecting part 211 at the front end of the tooth frame 21, and the effective length of the feeding arm 231 is smaller than that of the feeding connecting rod 24; the thread cutting mechanism 30 includes a movable blade 31, and a thread cutting transmission unit drivingly connected between the feeding thread cutting drive source 10 and the movable blade 31. The effective length of the feed arm 231 refers to: the distance between the center of rotation of the feed arm 231 and the centers of rotation of the feed arm 231 and feed link 24; the effective length of the feed link 24 is: the distance between the rotation centers of the feed arm 231 and the feed link 24 and the rotation centers of the feed link 24 and the feed crank 26 is a short crank-long link structure.

In the process that the feeding wire cutting driving source 10 drives the driving crank 23 to rotate, the feeding arm 231 of the driving crank 23 synchronously rotates; as shown in fig. 4, the angle of the feeding arm 231 has a feeding working area X1, and the angles of the two ends of the feeding working area X1 are respectivelyAnd/>When the feeding arm 231 runs in the feeding working area X1, the feeding arm 231 drives the feeding crank 26 to swing through the feeding connecting rod 24, the feeding shaft 25 and the dental frame seat 27 synchronously swing along with the feeding crank 26, and further the dental frame 21 is driven to reciprocate back and forth, and the feeding teeth 22 synchronously reciprocate back and forth along with the dental frame 21 to execute feeding action. When the wire is needed to be cut, the wire cutting driving source drives the moving knife 31 to move through the wire cutting transmission unit, and the wire cutting mechanism 30 executes automatic wire cutting action. Therefore, the feeding and thread cutting mechanism has a feeding function and an automatic thread cutting function; the power of the tooth rack 21 in the feeding mechanism 20 is derived from the feeding wire cutting driving source 10, the transmission chain between the tooth rack 21 and the feeding wire cutting driving source 10 is short, the whole structure is very compact and simplified, thereby improving the stability and being convenient to implement; meanwhile, the space occupation is small, and interference to the layout and installation of other functional mechanisms in the sewing machine is avoided.

Further, when the feed arm 231 is operated in the feed work area X1, the sewing machine has an effective stitch including a positive stitch corresponding to a positive stitch state of the sewing machine and a negative stitch corresponding to a reverse stitch state of the sewing machine. In addition, by adjusting the output of the feeding wire cutting driving source 10, the swing range of the feeding arm 231 of the driving crank 23 in the feeding working area X1 is adjusted, so as to adjust the effective stitch length of the sewing machine, thereby realizing the adjustment of the feeding stitch length, and adjusting the movement track of the feeding tooth 22. Such as: the feeding tooth 22 may be provided with an elliptical motion profile as shown in fig. 7a, or the feeding tooth 22 may be provided with a nearly vertical motion profile as shown in fig. 7b, or the feeding tooth 22 may be provided with a far vertical motion profile as shown in fig. 7c, or the feeding tooth 22 may be provided with a rectangular motion profile as shown in fig. 7 d. Thus, the feeding thread cutting mechanism has the functions of step-by-step stitch length adjustment, reverse stitching switching, feeding track switching, pattern stitching and the like.

Further, as shown in fig. 1 to 3, the feeding thread cutting mechanism further includes an integrated mounting base 40, and the feeding thread cutting driving source 10, the feeding mechanism 20 and the thread cutting mechanism 30 are mounted on the integrated mounting base 40 independently of the remaining driving sources in the sewing machine. Thus, the feeding and thread cutting driving source 10, the feeding mechanism 20, the thread cutting mechanism 30 and the integrated mounting base 40 are integrated into a single functional module, that is, the feeding mechanism 20 and the thread cutting mechanism 30 are independently modularized, so that the feeding and thread cutting mechanism is a single feeding and thread cutting module, and is independent of other functional mechanisms in the sewing machine. After the independent modularized structure is adopted, the installation and the disassembly of the independent feeding thread cutting module in the sewing machine are realized through the installation and the disassembly of the integrated installation base 40 in the sewing machine, the rapid adapting installation of the independent feeding thread cutting module in various types of sewing machines is realized, and the compatibility is strong, namely, the novel design platform of the sewing machine is developed.

Preferably, as shown in fig. 1 and 2, the feeding and wire cutting driving source 10 is a driving motor 11, and a driving crank 23 is fixed on a motor shaft of the driving motor 11 through a fastener such as a screw; the driving motor 11 is preferably a stepping motor; the center of the motor shaft of the driving motor 11 is the rotation center of the feeding arm 231. The integrated mounting base 40 has a horizontally disposed mounting main plate 41, and a motor mounting plate 42 extending vertically from the right end of the mounting main plate 41, and the drive motor 11 is fixed to the right end side of the motor mounting plate 42 by fasteners such as screws, and the motor shaft of the drive motor 11 is inserted into the motor mounting plate 42. The integrated mounting base 40 further includes a feed support portion 43 integrally extending from the mounting main plate 41, and the feed shaft 25 is rotatably supported in the feed support portion 43 of the integrated mounting base 40 by means of a bearing, a bushing, or the like; in the axial direction of the feed shaft 25, the feed crank 26 is disposed on the right side of the feed support portion 43, and the dental frame seat 27 is disposed on the left side of the feed support portion 43, so that the feed crank 26 and the dental frame seat 27 are disposed on both sides of the feed shaft 25 in the axial direction of the feed shaft 25. In addition, the rotational connection, i.e., the articulation, is achieved between one end of the feed link 24 and the outer end of the feed arm 231, and between the other end of the feed link 24 and the feed crank 26 by pins extending in the left-right axial direction, and bearings fitted between the pins and the ends of the feed link 24.

Further, as shown in fig. 1 to 3, the wire cutting transmission unit includes a wire cutting arm 232 driven to rotate by the feeding wire cutting driving source 10, a wire cutting clutch assembly, a wire cutting shaft 32 extending in the left-right axial direction, and a wire cutting transmission assembly; the thread cutting arm 232 and the driving crank 23 are driven to rotate by the feeding thread cutting driving source 10, and can be a split piece and fixed on a motor shaft of the feeding thread cutting driving source 10 through screws, or the thread cutting arm 232 is fixed on the driving crank 23. In this embodiment, the wire cutting arm 232 integrally extends from the outer periphery of the driving crank 23, and the wire cutting arm 232 on the driving crank 23 and the feeding arm 231 are distributed in a staggered manner in the circumferential direction; the integrated mounting base 40 further includes a wire cutting support portion 44 integrally extended from the mounting main plate 41, and the wire cutting shaft 32 is rotatably supported in the wire cutting support portion 44 of the integrated mounting base 40 by means of a bearing, a bushing, or the like; the thread cutting clutch assembly comprises a thread cutting ball 33, a thread cutting driving piece 34 fixed at the right end of the thread cutting shaft 32, and a thread cutting driving arm 341 extends out of the thread cutting driving piece 34; the thread cutting ball 33 is rotatably installed on the thread cutting arm 232 and the thread cutting driving arm 341 is provided with a thread cutting sliding groove surface, or the thread cutting ball 33 is rotatably installed on the thread cutting driving arm 341 and the thread cutting arm 232 is provided with a thread cutting sliding groove surface; in this embodiment, the thread cutting ball 33 is rotatably mounted on the thread cutting arm 232, and the outer circumferential surface of the thread cutting driving arm 341 has a thread cutting sliding groove surface; the wire cutting transmission assembly is in transmission connection between the left end of the wire cutting shaft 32 and the movable blade 31. Of course, in other embodiments, the wire cutting arm 232 on the driving crank 23 and the feeding arm 231 may be circumferentially coincident, and may be the same arm.

Further, as shown in fig. 4, in the process of driving the driving crank 23 to rotate by the driving motor 11, the feeding arm 231 further has a cutting working area X2, the feeding working area X1 and the cutting working area X2 are independent from each other, and the angles of both ends of the cutting working area X2 are respectivelyAnd/>In the forward rotation direction of the drive motor 11 when the sewing machine cuts thread,/>Thus, the angle range of the feeding working area X1 of the feeding arm 231 is/>The angle range of the trimming working area X2 of the feeding arm 231 is/>The angle of the feed arm 231 also has an idle zone X3 distributed between the feed working zone X1 and the cutting working zone X2, the idle zone X3 of the feed arm 231 having an angle range/>

When the feeding arm 231 runs in the feeding working area X1, the feeding tooth 22 feeds normally, and at this time, as shown in fig. 5, the wire cutting ball 33 is separated from the wire cutting sliding groove surface on the wire cutting driving arm 341, so that the wire cutting clutch assembly is in a separated state and does not transmit power, the wire cutting transmission unit does not transmit power, and the wire cutting mechanism 30 does not execute wire cutting action. When the wire is needed to be cut, the driving motor 11 drives the feeding arm 231 to rotate forward from the current angle in the feeding working area X1 to the initial angle of the wire cutting working area X2Then along the forward rotation to the end point angle/>, of the cutting working area X2From/>, at the feed arm 231Forward turn to/>In this process, the feeding arm 231 runs in the wire cutting working area X2, the wire cutting ball 33 gradually approaches the wire cutting sliding groove surface of the wire cutting driving arm 341 until contacting, as shown in fig. 6, the wire cutting clutch assembly is in an engaged state and transmits power, then the feeding arm 231 contacts the wire cutting sliding groove surface of the wire cutting driving arm 341 through the wire cutting ball 33 to push the wire cutting driving member 34, so as to drive the wire cutting shaft 32 to rotate, and then the wire cutting driving assembly drives the movable knife 31 to move, so that the wire cutting mechanism 30 automatically cuts wires. Therefore, the feeding and wire cutting mechanism realizes the simultaneous feeding and wire cutting driving by adopting the same driving motor 11, and the feeding driving and the wire cutting driving are not mutually interfered.

Preferably, the wire cutting mechanism 30 may be a single-action knife structure or a double-action knife structure. In this embodiment, as shown in fig. 1 and 2, the wire cutting mechanism 30 is a single-action knife structure, and the wire cutting mechanism 30 further includes a fixed knife 35 fixedly arranged, the wire cutting transmission assembly includes a wire cutting crank 36 fixed on the wire cutting shaft 32, a wire cutting connecting rod 37, and a rotatable movable knife rest 38, two ends of the wire cutting connecting rod 37 are respectively hinged with the wire cutting crank 36 and the movable knife rest 38, and the movable knife 31 is fixed on the movable knife rest 38.

Preferably, as shown in fig. 1 and 2, the wire cutting mechanism 30 further includes a return torsion spring 39 sleeved on the wire cutting shaft 32, and both ends of the return torsion spring 39 are respectively connected with the integrated mounting base 40 and the wire cutting crank 36. After the thread cutting is finished, the driving motor 11 reversely rotates to drive the feeding arm 231 to cut the thread from the end point angle of the thread cutting working area X2The current angle in the feeding working area X1 before the wire cutting is reversed, and under the action of the reset torsion spring 39, the wire cutting crank 36 is driven to reset, namely the wire cutting shaft 32, the wire cutting connecting rod 37, the movable knife rest 38 and other parts are driven to reset respectively; also, the return torsion spring 39 maintains the wire cutting crank 36 in its initial position when wire cutting is not required. More preferably, as shown in fig. 5 and 6, a reset arm 342 is further extended from the wire cutting driving member 34, the reset arm 342 and the wire cutting driving arm 341 are distributed in a staggered manner in the circumferential direction, and the outer circumferential surface of the reset arm 342 is provided with a section of forced reset surface; the feeding arm 231 is driven by the driving motor 11 from the end point angle/>, of the trimming working area X2When the reversing starts, the forced reset surface on the reset arm 342 is in contact fit with the thread cutting balls 33, the thread cutting balls 33 push the reset arm 342 to reset, so that the thread cutting driving piece 34 is driven to forcibly reset, all parts in the thread cutting mechanism 30 are driven to forcibly reset, the risk that the movable knife 31 cannot reset smoothly due to the fact that the movable knife 31 is blocked by thread is avoided, the movable knife 31 can be prevented from being blocked by the thread, and the next smooth automatic thread cutting is ensured.

Further, the following configuration is performed on the position angles of the feeding arm 231 and the feeding link 24, so that the moving distance of the feeding tooth 22 in the front-rear direction in the thread cutting process is as small as possible, thereby realizing the thread cutting effect of the stub and improving the experience of customers. As shown in fig. 8, the point C is the center of the motor shaft of the driving motor 11, and the point D is the rotation centers of the feeding arm 231 and the feeding link 24, with the rotation center C of the feeding arm 231 as the center and the effective length CD of the feeding arm 231 as the radius O1; the hinge point B of the feeding connecting rod 24 and the driving crank 23 is used as a circle center, the effective length BD of the feeding connecting rod 24 is used as a radius to be used as a circle O2, and the point A is used as the center of the feeding shaft 25. Circles O1 and O2 are substantially coincident within ± β angles of the collinear position of the feed arm 231 and feed link 24. The angle of the feed arm 231 is shown as beingThen the feed arm 231 is at/>During this range of motion, the feed crank 26 remains substantially stationary, i.e., the feed dog 22 is displaced in the fore-aft direction by a small amount and is not fed substantially. Namely: when the angle of the feed arm 231 is at/>When the range is within, the feeding thread cutting mechanism enables the sewing machine to have small needle distance; in this embodiment, when the angle of the feeding arm 231 is at/>Within this range, the feed thread cutting mechanism makes the movement amount of the feed dog 22 in the front-rear direction not more than 1mm. Based on this, the trimming working area X2 of the feed arm 231 is set at/>Within this range, the distance of movement of the feed dog 22 in the front-rear direction during the thread cutting process is made very small; the trimming working area X2 of the feeding arm 231 may be set as: /(I)Thus, the wire cutting working area X2 of the feeding arm 231 may have three embodiments as follows.

Embodiment one of the wire cutting work area X2 of the feed arm 231 as shown in figure 9a,

In a second embodiment of the cutting work area X2 of the feeding arm 231 as shown in figure 9b,

Third embodiment of the wire cutting work area X2 of the feed arm 231 as shown in figure 9c,

Further, when the feed arm 231 is collinear with the feed link 24, the feed dog 22 is positioned at a front limit position within the range of the back and forth reciprocating movement thereof, and there is a minimum limit distance between the feed dog 22 and the tooth slot front end of the needle plate. Or when the feed arm 231 is collinear with the feed link 24, the feed dog 22 is at a rear limit position within the range of back and forth reciprocation thereof, and there is a minimum limit distance between the feed dog 22 and the rear end of the tooth slot of the needle plate.

Further, the application also provides a sewing machine, as shown in fig. 10, wherein the feeding thread cutting mechanism is arranged in the sewing machine. In addition, the sewing machine further comprises a lifting tooth driving source, a lifting tooth mechanism 50 and a bottom plate 60 fixedly arranged, wherein the lifting tooth mechanism 50 is in transmission connection between the lifting tooth driving source and a lifting tooth connecting part 212 at the rear end of the tooth frame 21, and the integrated mounting base 40 is detachably connected to the bottom of the bottom plate 60 of the sewing machine. By installing and detaching the integrated installation base 40 in the sewing machine, the installation and detaching of the whole feeding thread cutting mechanism in the sewing machine are realized, the feeding thread cutting mechanism is quickly and adaptively installed in various sewing machines as an independent functional mechanism, interference with other functional mechanisms of the sewing machine is avoided, and the compatibility is strong.

Preferably, the integrated mounting base 40 is detachably connected with the bottom plate 60 through a plurality of screws, so that the integrated mounting base is convenient to assemble and disassemble. As shown in fig. 10, the feed thread cutting mechanism is disposed on the left side of the base plate 60 near the sewing machine head.

Further, as shown in fig. 11 or 12, the lifting-tooth driving source is a main motor of the sewing machine, the lifting-tooth mechanism 50 includes a main shaft 51 driven to rotate by the main motor, a lifting-tooth shaft 52 parallel to the main shaft 51, a first lifting-tooth transmission assembly connected between the main shaft 51 and the lifting-tooth shaft 52, and a second lifting-tooth transmission assembly connected between the lifting-tooth shaft 52 and the lifting-tooth connecting portion 212 of the frame 21, and both the main shaft 51 and the lifting-tooth shaft 52 extend axially in the left-right direction.

When the feeding thread cutting mechanism is matched with the swinging type thread lifting machine, as shown in fig. 11, the first thread lifting transmission assembly comprises a thread lifting eccentric wheel 53 fixed on a main shaft 51, a thread lifting crank 54 fixed at the right end of a thread lifting shaft 52 and a thread lifting connecting rod 55, the upper end of the thread lifting connecting rod 55 is rotatably sleeved on the periphery of the thread lifting eccentric wheel 53, and the lower end of the thread lifting connecting rod 55 is hinged with the thread lifting crank 54; the second lifting tooth transmission assembly comprises a lifting tooth fork-shaped crank 56 fixed at the left end of the lifting tooth shaft 52 and a lifting tooth sliding block 57 hinged with a lifting tooth connecting part 212 of the tooth frame 21, wherein the lifting tooth fork-shaped crank 56 is provided with a lifting tooth sliding groove in sliding fit with the lifting tooth sliding block 57. The main motor drives the main shaft 51 to rotate, the main shaft 51 drives the lifting tooth shaft 52 to swing through the first lifting tooth transmission assembly, the lifting tooth shaft 52 drives the lifting tooth fork-shaped crank 56 to swing up and down through the second lifting tooth transmission assembly, and accordingly up-and-down reciprocating motion of the tooth frame 21 and the feeding tooth 22 is achieved, and the lifting tooth action is executed. The up-and-down lifting motion and the front-and-back feeding motion of the feeding teeth 22 together form a feeding track of the feeding teeth 22. Of course, in other embodiments, the second lifter transmission assembly may employ other configurations of transmission pairs.

When the feeding thread cutting mechanism is matched with the rotary thread lifting machine type, as shown in fig. 12, the first thread lifting transmission assembly comprises a driving belt pulley 58 fixed on the main shaft 51, a driven belt pulley 59 fixed on the right end of the thread lifting shaft 52, and a transmission belt 510 connected to the peripheries of the driving belt pulley 58 and the driven belt pulley 59, wherein the rotation speed ratio of the driving belt pulley 58 to the driven belt pulley 59 is 1:1; the second lifting tooth transmission assembly comprises a lifting tooth eccentric wheel 53 fixed at the left end of the lifting tooth shaft 52 and a lifting tooth connecting rod 55, one end of the lifting tooth connecting rod 55 is rotatably sleeved on the periphery of the lifting tooth eccentric wheel 53, and the other end of the lifting tooth connecting rod 55 is hinged with a lifting tooth connecting part 212 of the tooth frame 21. The main motor drives the main shaft 51 to rotate, the main shaft 51 drives the lifting tooth shaft 52 to rotate through the first lifting tooth transmission assembly, and the lifting tooth shaft 52 drives the tooth frame 21 and the feeding tooth 22 to reciprocate up and down through the second lifting tooth transmission assembly so as to execute the lifting tooth action. The up-and-down lifting motion and the front-and-back feeding motion of the feeding teeth 22 together form a feeding track of the feeding teeth 22. Of course, in other embodiments, the second lifter transmission assembly may employ other configurations of transmission pairs.

In summary, the present invention effectively overcomes the disadvantages of the prior art and has high industrial utility value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. 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 invention. Accordingly, it is intended that all equivalent modifications and variations of the invention 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 (12)

1. Feeding thread cutting mechanism based on long connecting rod short crank structure, its characterized in that: comprises a feeding and thread cutting driving source (10), a feeding mechanism (20) and a thread cutting mechanism (30);

The feeding mechanism (20) comprises a dental floss holder (21), a feeding tooth (22) fixed on the dental floss holder (21), a driving crank (23) driven by a feeding shear line driving source (10) to rotate, a feeding arm (231) extending from the driving crank (23), a feeding connecting rod (24), a feeding shaft (25) capable of rotating around the axis of the feeding connecting rod, a feeding crank (26) fixed at one end of the feeding shaft (25) and a dental floss holder (27) fixed at the other end of the feeding shaft (25), wherein one end of the dental floss holder (21) is provided with a feeding connecting part (211), two ends of the feeding connecting rod (24) are respectively connected with the feeding arm (231) and the feeding crank (26) in a rotating mode, and the effective length of the feeding arm (231) is smaller than that of the feeding connecting rod (24);

the thread cutting mechanism (30) comprises a movable cutter (31) and a thread cutting transmission unit which is in transmission connection between the feeding thread cutting driving source (10) and the movable cutter (31).

2. The feed scissor wire mechanism of claim 1, wherein: the feeding wire cutting driving source (10) is a driving motor (11), and the driving crank (23) is fixed on a motor shaft of the driving motor (11).

3. The feed scissor wire mechanism of claim 1, wherein: the automatic feeding and trimming device further comprises an integrated mounting base (40), wherein the feeding and trimming driving source (10) is independent of other driving sources in the sewing machine, and the feeding and trimming driving source (10), the feeding mechanism (20) and the trimming mechanism (30) are all mounted on the integrated mounting base (40).

4. A feed scissor wire mechanism according to claim 3, characterized in that: the integrated mounting base (40) is provided with a feeding supporting part (43), the feeding shaft (25) is rotatably supported in the feeding supporting part (43) of the integrated mounting base (40), and the feeding crank (26) and the dental frame seat (27) are distributed along the axial direction of the feeding shaft (25).

5. The feed scissor wire mechanism of claim 1, wherein: when the feeding arm (231) is collinear with the feeding connecting rod (24), the angle of the feeding arm (231) isWhen the angle of the feeding arm (231) is at/>Within this range, the feed thread cutting mechanism makes the sewing machine have a small stitch length.

6. The feed scissor wire mechanism of claim 5, wherein: when the angle of the feeding arm (231) is atWithin this range, the feed thread cutting mechanism makes the movement amount of the feed dog (22) in the front-rear direction not more than 1mm.

7. The feed scissor wire mechanism of claim 1, wherein: when the feeding arm (231) is collinear with the feeding link (24), the feeding tooth (22) is located at a front limit position or a rear limit position within the front-rear reciprocating movement range.

8. A sewing machine, characterized in that: the sewing machine is provided with the feeding thread cutting mechanism as claimed in any one of claims 1 to 7.

9. The sewing machine of claim 8, wherein: the novel lifting tooth mechanism is characterized by further comprising a lifting tooth driving source and a lifting tooth mechanism (50), wherein a lifting tooth connecting part (212) is arranged at the other end of the tooth frame (21), and the lifting tooth mechanism (50) is in transmission connection between the lifting tooth driving source and the lifting tooth connecting part (212) of the tooth frame (21).

10. The sewing machine of claim 9, wherein: the lifting tooth driving source is a main motor of the sewing machine, and the lifting tooth mechanism (50) comprises a main shaft (51) driven by the main motor to rotate, a lifting tooth shaft (52) parallel to the main shaft (51), a first lifting tooth transmission assembly connected between the main shaft (51) and the lifting tooth shaft (52), and a second lifting tooth transmission assembly connected between the lifting tooth shaft (52) and a lifting tooth connecting part (212) of the tooth frame (21).

11. The sewing machine of claim 10, wherein: the first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel (53) fixed on the main shaft (51), a lifting tooth crank (54) fixed at one end of the lifting tooth shaft (52) and a lifting tooth connecting rod (55), one end of the lifting tooth connecting rod (55) is rotatably sleeved on the periphery of the lifting tooth eccentric wheel (53), and the other end of the lifting tooth connecting rod (55) is hinged with the lifting tooth crank (54); the second lifting tooth transmission assembly comprises a lifting tooth fork crank (56) fixed at the other end of the lifting tooth shaft (52) and a lifting tooth sliding block (57) hinged with a lifting tooth connecting part (212) of the tooth frame (21), and the lifting tooth fork crank (56) is internally provided with a lifting tooth sliding groove in sliding fit with the lifting tooth sliding block (57).

12. The sewing machine of claim 10, wherein: the first lifting tooth transmission assembly comprises a driving belt wheel (58) fixed on the main shaft (51), a driven belt wheel (59) fixed at one end of the lifting tooth shaft (52), and a transmission belt (510) connected to the peripheries of the driving belt wheel (58) and the driven belt wheel (59); the second lifting tooth transmission assembly comprises a lifting tooth eccentric wheel (53) fixed at the other end of the lifting tooth shaft (52) and a lifting tooth connecting rod (55), one end of the lifting tooth connecting rod (55) is rotatably sleeved on the periphery of the lifting tooth eccentric wheel (53), and the other end of the lifting tooth connecting rod (55) is hinged to a lifting tooth connecting part (212) of the tooth frame (21).