A feeding and cutting mechanism based on long connecting rod and short crank structure and sewing machine

Abstract

The application provides a feeding and thread cutting mechanism based on a long connecting rod and short crank structure and a sewing machine. The feeding and thread cutting mechanism comprises a feeding and thread cutting driving source, a feeding mechanism and a thread cutting mechanism. The feeding mechanism comprises a rack, a feeding tooth, a driving crank driven to rotate by the feeding and thread cutting driving source, a feeding arm extended from the driving crank, a feeding connecting rod, a feeding shaft rotatable around its own axis, a feeding crank fixed at one end of the feeding shaft, and a rack seat fixed at the other end of the feeding shaft. The feeding connecting rod is rotatably connected with the feeding arm and the feeding crank at two ends respectively. The rack seat is connected with the feeding connection part of the rack. The effective length of the feeding arm is smaller than that of the feeding connecting rod. In the application, the power of the rack in the feeding mechanism is derived from the feeding and thread cutting driving source. The transmission chain between the rack and the feeding and thread cutting driving source is short. The overall structure is simple and stable. The feeding and thread cutting mechanism occupies a small space and avoids interference with the layout and installation of other functional mechanisms in the sewing machine.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewing machine technical field, in particular to a feeding and thread cutting mechanism based on a long connecting rod and short crank structure, and a sewing machine comprising the feeding and thread cutting mechanism. BACKGROUND

[0002] At present, major sewing machine companies have their own design platforms, and the feeding mechanism, the tooth lifting mechanism, the thread cutting mechanism and the presser foot lifting mechanism are important functional mechanisms of the sewing machine. Once the design platform of a company is determined, the research and development of its products and next-generation products are based on iterative updates of the design platform, and almost no new design platform is developed.

[0003] For example, the driving mechanism of a lockstitch machine disclosed in Chinese Utility Model Patent No. 201220297729.6 drives the tooth lifting shaft and the feeding shaft to rotate through the main shaft (i.e., the upper shaft), the main shaft is driven to rotate by the main motor, the tooth lifting shaft drives the tooth carrier and the feeding tooth to move up and down through a set of tooth lifting components to perform the tooth lifting action, the feeding shaft drives the tooth carrier and the feeding tooth to move back and forth through a set of feeding components to perform the feeding action, and at the same time, the main shaft also drives the lower shaft to rotate through a set of synchronous belt mechanisms, the lower shaft drives the rotating shuttle mechanism to rotate to perform the thread hooking action. Further, the sewing machine can be equipped with a thread cutting mechanism, such as the automatic thread cutting mechanism disclosed in Chinese Invention Patent No. 201710215982.X. When the thread needs to be cut, the thread cutting drive source is actuated to make the thread cutting ball contact the thread cutting cam fixed on the lower shaft, and then the rotation of the lower shaft drives the thread cutting component to rotate to perform the automatic thread cutting action. Obviously, the structure of the sewing machine is relatively complex, the number of parts is large, the transmission chain is long, and a clutch assembly is provided in the thread cutting mechanism to achieve the thread cutting action.

[0004] For another example, the sewing machine disclosed in Chinese Invention Patent No. 201210365288.3 is driven by the main shaft in the sewing machine, the main shaft is driven to rotate by the main motor, the feeding mechanism is driven by a feeding motor, and the clutch of the thread cutting mechanism is also driven by the feeding motor. When the thread is cut, the feeding motor drives the transmission components in the thread cutting mechanism to combine, and the thread cutting component is still driven to rotate by the thread cutting cam on the lower shaft to perform the automatic thread cutting action. Obviously, the structure of the sewing machine is complex, especially the use of the slot cam structure, which is difficult to implement, and the main motor still needs to drive the main shaft to rotate to drive the lower shaft to rotate to drive the thread cutting cam to rotate to complete the thread cutting action.

[0005] For example, the sewing machine thread cutting and presser foot lifting device disclosed in the Chinese Utility Model Patent No. 201520782770.6 is driven by a set of complex mechanisms. However, since the final execution end (i.e. the moving knife and the fixed knife) of the thread cutting mechanism is arranged at the left end of the bottom plate, and the final execution end (i.e. the presser foot) of the presser foot mechanism is arranged at the head, the span between the stepping motor and the moving knife, and the span between the stepping motor and the presser foot are large, resulting in a long overall transmission chain of the sewing machine, and the stepping motor and the transmission structure occupy most of the installation space in the bottom plate, which interferes with the arrangement and installation of other transmission structures in the sewing machine.

[0006] For example, the sewing machine with positioning feed dog stop position disclosed in the Chinese Utility Model Patent No. 202120273965.3 is driven by a stepping motor to rotate the swing seat, so that the swing seat is at different position angles, and different position angles of the swing seat correspond to different stitch sizes; at the same time, the stepping motor also drives the thread cutting fork wheel and other thread cutting components to operate, and performs thread cutting action. However, the sewing machine with this structure has many parts, a long transmission chain, poor structural stability, and relatively complex stitch adjustment, thread cutting drive, and other transmissions, and also uses a slot cam structure which is difficult to implement.

[0007] In summary, the existing sewing machine has the following problems: 1. Complex structure, resulting in poor stability and difficult implementation; 2. Long transmission chain, resulting in transmission structures including stepping motor occupying most of the installation space of the machine, interfering with the arrangement and installation of other structures; 3. Single function, the power of the thread cutting mechanism still depends on the main shaft, or in other words, still depends on the main motor, and the power source configured in the thread cutting mechanism can only realize the switching of thread cutting clutch. SUMMARY

[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a feeding and thread cutting mechanism based on long connecting rod and short crank structure, which can shorten the transmission chain of the feeding transmission part and simplify its structure.

[0009] To achieve the above-mentioned purpose, the present application provides a feeding and thread cutting mechanism based on long connecting rod and short crank structure, which comprises a feeding and thread cutting driving source, a feeding mechanism and a thread cutting mechanism.

[0010] The feeding mechanism comprises a frame, a feeding tooth fixed on the frame, a driving crank driven to rotate by a feeding thread cutting driving source, a feeding arm extended from the driving crank, a feeding connecting rod, a feeding shaft rotatable about its own axis, a feeding crank fixed on one end of the feeding shaft, and a frame seat fixed on the other end of the feeding shaft, one end of the frame is provided with a feeding connecting part, two ends of the feeding connecting rod are respectively rotatably connected with the feeding arm and the feeding crank, the frame seat is connected with the feeding connecting part of the frame, and the effective length of the feeding arm is less than the effective length of the feeding connecting rod.

[0011] The thread cutting mechanism comprises a movable cutter and a thread cutting transmission unit in transmission connection between the feeding thread cutting driving source and the cutter.

[0012] Further, the feeding thread cutting driving source is a driving motor, and the driving crank is fixed on a motor shaft of the driving motor.

[0013] Further, the feeding thread cutting mechanism further comprises an integrated installation base, the feeding thread cutting driving source is independent of the remaining driving sources in the sewing machine, and the feeding thread cutting driving source, the feeding mechanism and the thread cutting mechanism are all installed on the integrated installation base.

[0014] Further, the integrated installation base has a feeding support part, the feeding shaft is rotatably supported in the feeding support part of the integrated installation base, and the feeding crank and the frame seat are distributed along the axial direction of the feeding shaft.

[0015] Further, when the feeding arm is collinear with the feeding connecting rod, the angle of the feeding arm is When the angle of the feeding arm is in the range of , the feeding thread cutting mechanism enables the sewing machine to have a small needle pitch.

[0016] Further, when the angle of the feeding arm is in the range of , the feeding thread cutting mechanism enables the feeding tooth (22) to have a movement in the front and back direction of not more than 1 mm.

[0017] Further, when the feeding arm is collinear with the feeding connecting rod, the feeding tooth is located at a front limit position or a back limit position in the front and back reciprocating movement range thereof.

[0018] The application further provides a sewing machine, wherein the feeding thread cutting mechanism as described above is arranged in the sewing machine.

[0019] Further, the sewing machine further comprises a tooth lifting driving source and a tooth lifting mechanism, the other end of the frame is provided with a tooth lifting connecting part, and the tooth lifting mechanism is in transmission connection between the tooth lifting driving source and the tooth lifting connecting part of the frame.

[0020] Further, the lifting tooth driving source is a main motor of the sewing machine, the lifting tooth mechanism comprises a main shaft driven to rotate by the main motor, 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 portion of the tooth frame.

[0021] Further, the first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel fixed on the main shaft, a lifting tooth crank fixed on 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 outer 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 crank fixed on the other end of the lifting tooth shaft, and a lifting tooth sliding block hinged with the lifting tooth connecting portion of the tooth frame, the lifting tooth fork crank has a lifting tooth sliding groove slidingly matched with the lifting tooth sliding block.

[0022] Further, the first lifting tooth transmission assembly comprises a driving pulley fixed on the main shaft, a driven pulley fixed on one end of the lifting tooth shaft, and a transmission belt connected between the outer peripheries of the driving pulley and the driven pulley; the second lifting tooth transmission assembly comprises a lifting tooth eccentric wheel fixed on the other 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 outer periphery of the lifting tooth eccentric wheel, and the other end of the lifting tooth connecting rod is hinged with the lifting tooth connecting portion of the tooth frame.

[0023] As described above, the feeding and cutting mechanism based on the long connecting rod and short crank structure and the sewing machine according to the present application have the following beneficial effects:

[0024] In the present application, the power of the tooth frame in the feeding mechanism comes from the feeding and cutting driving source, the transmission chain between the tooth frame and the feeding and cutting driving source is short, the overall structure is very compact and simple, thereby improving the stability and facilitating the implementation; at the same time, it occupies small space and avoids interference with the layout and installation of other functional mechanisms in the sewing machine. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a structural schematic diagram of the feeding and cutting mechanism in the present application.

[0026] Figure 2 FIG. 2 is an exploded view of FIG. 1, which omits the integrated mounting base. Figure 1

[0027] FIG. 3 is a left view of FIG. 1, which omits the integrated mounting base. Figure 3 Figure 1 FIG. 4 is a distribution schematic diagram of the working area of the feeding arm in the feeding and cutting mechanism.

[0028] Figure 4

[0029] Figure 5 ​​Figure 7 is a schematic view of the disengaged state of the thread cutting clutch assembly in the thread cutting and feeding mechanism.

[0030] Figure 6 Figure 8 is a schematic view of the engaged state of the thread cutting clutch assembly in the thread cutting and feeding mechanism.

[0031] Figures 7a to 7d Figure 9 is a schematic view of the four movement trajectories of the feeding teeth in the thread cutting and feeding mechanism.

[0032] Figure 8 Figure 10 is a schematic view of the position of the feeding arm and feeding connecting rod in line in the thread cutting and feeding mechanism.

[0033] Figures 9a to 9c Figure 11 is a schematic view of the three distributions of the thread cutting working area of the feeding arm in the thread cutting and feeding mechanism.

[0034] Figure 10 Figure 12 is a schematic view of the distribution position of the thread cutting and feeding mechanism in the sewing machine.

[0035] Figure 11 Figure 13 is a schematic view of the structure of the first embodiment of the sewing machine in the present application.

[0036] Figure 12 Figure 14 is a schematic view of the structure of the second embodiment of the sewing machine in the present application.

[0037] Element number explanation

[0038] 10 Thread cutting and feeding driving source

[0039] 11 Driving motor

[0040] 20 Feeding mechanism

[0041] 21 Tooth holder

[0042] 211 Feeding connecting portion

[0043] 212 Tooth lifting connecting portion

[0044] 22 Feeding tooth

[0045] 23 Driving crank

[0046] 231 Feeding arm

[0047] 232 Thread cutting arm

[0048] 24 Feeding connecting rod

[0049] 25 Feeding shaft

[0050] 26 Feeding crank

[0051] 27 Tooth holder seat

[0052] 30 Thread cutting mechanism

[0053] 31. Cutting

[0054] 32 Thread cutter spool

[0055] 33 Wire-cutting ball bearing

[0056] 34 Wire cutting drive unit

[0057] 341 Wire Cutting Drive Arm

[0058] 342 Reset Arm

[0059] 35 Fixed cutter

[0060] 36 Wire-cutting crank

[0061] 37. Wire-cutting connecting rod

[0062] 38. Moving tool holder

[0063] 39. Return torsion spring

[0064] 40 Integrated mounting base

[0065] 41 Installing the motherboard

[0066] 42 Motor mounting plate

[0067] 43 Feeding support section

[0068] 44. Wire cutting support section

[0069] 50 Tooth Lifting Mechanism

[0070] 51 Spindle

[0071] 52 Tooth-lifting shaft

[0072] 53 Eccentric tooth lifting wheel

[0073] 54. Crank handle for lifting teeth

[0074] 55. Tooth-lifting linkage

[0075] 56. Lifting tooth fork-shaped crank

[0076] 57 Tooth-lifting slider

[0077] 58 Drive pulley

[0078] 59 Driven pulley

[0079] 510 Transmission Belt

[0080] 60 base plate Detailed Implementation

[0081] The present application will be best understood by reference to the following description of specific embodiments thereof, given by way of example only, and with reference to the accompanying drawings, in which:

[0082] It is to be understood that the structures, proportions, sizes, etc. shown in the drawings are to be interpreted as illustrative only and the scope of the present application is not to be limited to them. Any modification, change or adjustment to the structures, proportions, sizes, etc. of the structures described in the present application, which do not materially alter the technical content of the present application, shall still fall within the scope of the technical content disclosed in the present application. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present application are only for the convenience of description and do not limit the scope of the present application. Any change to the relative relationship thereof without materially altering the technical content shall still be considered as falling within the scope of the present application.

[0083] The present application relates to a feeding and cutting mechanism based on a long connecting rod and short crank structure, and a sewing machine comprising the feeding and cutting mechanism. For the convenience of description, in the following embodiments, the directions are defined as follows: the length direction of the sewing machine is defined as the left-right direction, and the direction towards the head of the sewing machine is the left direction, and the direction towards the tail of the sewing machine is the right direction, and the left-right direction is also 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, and the width direction of the sewing machine is defined as the front-back direction, and the moving direction of the sewing material when the sewing machine is sewing is the front direction.

[0084] As Figures 1 to 3As shown, the feeding and thread cutting mechanism based on the long connecting rod and short crank structure of the present application comprises a feeding and thread cutting driving source 10, a feeding mechanism 20 and a thread cutting mechanism 30; wherein the feeding mechanism 20 comprises a tooth frame 21, feeding teeth 22 fixed on the upper end surface of the tooth frame 21, a driving crank 23 driven to rotate by the feeding and thread cutting driving source 10, a feeding arm 231 extended from the driving crank 23, a feeding connecting rod 24, a feeding shaft 25 rotatable about its own axis and extending leftward and rightward, 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, the front end of the tooth frame 21 is a feeding connecting part 211, the rear end of the tooth frame 21 is a tooth lifting connecting part 212, the two ends of the feeding connecting rod 24 are rotatably connected with the feeding arm 231 and the feeding crank 26, i.e. 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 less than that of the feeding connecting rod 24; the thread cutting mechanism 30 comprises a movable cutter 31 and a thread cutting transmission unit transmissionally connected between the feeding and thread cutting driving source 10 and the movable cutter 31. The effective length of the feeding arm 231 refers to the distance between the rotation center of the feeding arm 231 and the rotation centers of the feeding arm 231 and the feeding connecting rod 24; the effective length of the feeding connecting rod 24 refers to the distance between the rotation centers of the feeding arm 231 and the feeding connecting rod 24 and the rotation centers of the feeding connecting rod 24 and the feeding crank 26, i.e. the structure of short crank and long connecting rod is adopted.

[0085] In the process that the feeding and thread cutting driving source 10 drives the driving crank 23 to rotate, the feeding arm 231 of the driving crank 23 rotates synchronously; Figure 4 As shown, the angle of the feeding arm 231 has a feeding working area X1, the angles at the two ends of the feeding working area X1 are and When the feeding arm 231 operates 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 tooth frame seat 27 swing synchronously with the feeding crank 26, thereby driving the tooth frame 21 to move back and forth, the feeding teeth 22 move back and forth synchronously with the tooth frame 21 to perform the feeding action. When the thread needs to be cut, the thread cutting driving source drives the movable cutter 31 to move through the thread cutting transmission unit, and the thread cutting mechanism 30 performs the automatic thread cutting action. Therefore, the feeding and thread cutting mechanism has the feeding function and the automatic thread cutting function; the power source of the tooth frame 21 in the feeding mechanism 20 is derived from the feeding and thread cutting driving source 10, the transmission chain between the tooth frame 21 and the feeding and thread cutting driving source 10 is short, the overall structure is very compact and simple, thereby improving the stability and facilitating the implementation; at the same time, it occupies small space and avoids interference with the layout and installation of other functional mechanisms in the sewing machine.

[0086] Further, when the feeding arm 231 operates in the feeding working area X1, the sewing machine has an effective stitch length, which includes a positive stitch length corresponding to the forward sewing state of the sewing machine and a negative stitch length corresponding to the reverse sewing state of the sewing machine. In addition, by adjusting the output of the feeding and trimming driving source 10, the swing range of the feeding arm 231 driven by the crank 23 in the feeding working area X1 is adjusted, and the effective stitch length of the sewing machine is adjusted, so that the feeding stitch length is adjusted, and the movement track of the feeding teeth 22 is adjusted. For example, the feeding teeth 22 can have an elliptical movement track as shown in Figure 7a , or a near-vertical movement track as shown in Figure 7b , or a far-vertical movement track as shown in Figure 7c , or a rectangular movement track as shown in Figure 7d . In this way, the feeding and trimming mechanism has the functions of step-adjusting the stitch length, switching the reverse sewing, switching the feeding track, and pattern sewing.

[0087] Further, as shown in Figures 1 to 3 , the feeding and trimming mechanism further includes an integrated mounting base 40, and the feeding and trimming driving source 10 is independent of the remaining driving sources in the sewing machine. 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. In this way, the feeding and trimming driving source 10, the feeding mechanism 20, the trimming mechanism 30, and the integrated mounting base 40 are integrated into an independent functional module, and the feeding mechanism 20 and the trimming mechanism 30 are modularized independently, so that the feeding and trimming mechanism is an independent feeding and trimming module, which is independent of other functional mechanisms in the sewing machine. After adopting the independent modular structure, the integrated mounting base 40 is mounted and detached in the sewing machine, so that the independent feeding and trimming module is mounted and detached as a whole in the sewing machine, and the independent feeding and trimming module is quickly adapted and mounted in various types of sewing machines, which has strong compatibility. That is, a novel design platform of the sewing machine is developed.

[0088] Preferably, as shown in Figure 1 and Figure 2As shown, the feeding and shearing line driving source 10 is a driving motor 11, and the driving crank 23 is fixed on the motor shaft of the driving motor 11 by screws or other fasteners; the driving motor 11 preferably adopts a stepping motor; the center of the motor shaft of the driving motor 11 is also the rotation center of the feeding arm 231. The integrated mounting base 40 has a horizontally arranged mounting main plate 41, and a motor mounting plate 42 vertically extending from the right end of the mounting main plate 41, and the driving motor 11 is fixed on the right end side of the motor mounting plate 42 by screws or other fasteners, and the motor shaft of the driving motor 11 penetrates the motor mounting plate 42. The integrated mounting base 40 further includes a feeding support part 43 integrally extending from the mounting main plate 41, and the feeding shaft 25 is rotatably supported in the feeding support part 43 of the integrated mounting base 40 by bearings, shaft sleeves or other components; along the axial direction of the feeding shaft 25, the feeding crank 26 is distributed on the right side of the feeding support part 43, and the tooth rack seat 27 is distributed on the left side of the feeding support part 43, so that the feeding crank 26 and the tooth rack seat 27 are distributed along the axial direction of the feeding shaft 25 and on both sides of the feeding shaft 25. In addition, the rotation connection, i.e. the hinge, between one end of the feeding connecting rod 24 and the outer end of the feeding arm 231, and between the other end of the feeding connecting rod 24 and the feeding crank 26 is achieved by a left-right axially extending pin and a bearing, and the bearing is assembled between the pin and the end of the feeding connecting rod 24.

[0089] Further, as Figures 1 to 3As shown, the wire cutting transmission unit includes a wire cutting arm 232 driven to rotate by the feeding wire cutting drive source 10, a wire cutting clutch assembly, a wire cutting shaft 32 extending axially to the left and right, and a wire cutting transmission assembly; the wire cutting arm 232 and the drive crank 23 are both driven to rotate by the feeding wire cutting drive source 10. The two can be separate parts, both fixed to the motor shaft of the feeding wire cutting drive source 10 by screws, or the wire cutting arm 232 is fixed to the drive crank 23. In this embodiment, the wire-cutting arm 232 extends integrally from the outer circumference of the drive crank 23, and the wire-cutting arm 232 on the drive crank 23 is circumferentially offset from the feeding arm 231; the integrated mounting base 40 also includes a wire-cutting support portion 44 integrally extending from the mounting main board 41, and the wire-cutting shaft 32 is rotatably supported in the wire-cutting support portion 44 of the integrated mounting base 40 by bearings, bushings and other components; the wire-cutting clutch assembly includes a wire-cutting ball 33 and a wire-cutting drive component 34 fixed to the right end of the wire-cutting shaft 32. A wire-cutting drive arm 341 extends from the 34th shaft; a wire-cutting ball 33 is rotatably mounted on the wire-cutting arm 232, and the wire-cutting drive arm 341 has a wire-cutting groove surface, or the wire-cutting ball 33 is rotatably mounted on the wire-cutting drive arm 341, and the wire-cutting arm 232 has a wire-cutting groove surface; in this embodiment, the wire-cutting ball 33 is rotatably mounted on the wire-cutting arm 232, and the outer circumferential surface of the wire-cutting drive arm 341 has a section of wire-cutting groove surface; the wire-cutting transmission assembly is drively connected between the left end of the wire-cutting shaft 32 and the moving blade 31. Of course, in other embodiments, the wire-cutting arm 232 on the drive crank 23 and the feeding arm 231 can overlap circumferentially, and can be the same arm.

[0090] Furthermore, such as Figure 4 As shown, during the process of the drive motor 11 driving the drive crank 23 to rotate, the angle of the feeding arm 231 also includes a wire-cutting working area X2. The feeding working area X1 and the wire-cutting working area X2 are independent of each other, and the angles of the two ends of the wire-cutting working area X2 are respectively and Along the forward rotation direction of the drive motor 11 when the sewing machine cuts the thread, Thus, the angle range of the feeding working area X1 of the feeding arm 231 is... The angle range of the wire cutting working area X2 of the feeding arm 231 is: The feeding arm 231 also has an idle area X3 distributed between the feeding working area X1 and the wire cutting working area X2. The angle range of the idle area X3 of the feeding arm 231 is as follows:

[0091] When the feeding arm 231 is operating within the feeding work area X1, the feeding tooth 22 feeds normally. At this time, if Figure 5As shown, the wire-cutting ball 33 separates from the wire-cutting groove surface on the wire-cutting drive arm 341, thus disengaging the wire-cutting clutch assembly and preventing power transmission. Consequently, the wire-cutting transmission unit does not transmit power, and the wire-cutting mechanism 30 does not perform the wire-cutting action. When wire cutting is required, the drive motor 11 drives the feeding arm 231 to rotate clockwise from the current angle in the feeding working area X1 to the starting angle in the wire-cutting working area X2. Then, continue rotating forward to the endpoint angle of the wire cutting work area X2. From the feed arm 231 Turning to During this process, the feeding arm 231 operates within the wire cutting working area X2, and the wire cutting ball 33 gradually approaches the wire cutting groove surface of the wire cutting drive arm 341 until it makes contact, as... Figure 6 As shown, the wire-cutting clutch assembly is engaged, transmitting power. Then, the feeding arm 231, through the contact and engagement of the wire-cutting ball bearing 33 with the wire-cutting groove surface of the wire-cutting drive arm 341, pushes the wire-cutting drive component 34, thereby driving the wire-cutting shaft 32 to rotate. This, in turn, drives the moving blade 31 through the wire-cutting transmission assembly, and the wire-cutting mechanism 30 performs automatic wire cutting. In this way, the feeding and wire-cutting mechanism achieves simultaneous feeding and wire-cutting using the same drive motor 11, and the feeding drive and wire-cutting drive do not conflict with each other.

[0092] Preferably, the wire-cutting mechanism 30 can be a single-moving-blade structure or a double-moving-blade structure. In this embodiment, for example... Figure 1 and Figure 2 As shown, the wire cutting mechanism 30 is a single-moving-blade structure. The wire cutting mechanism 30 also includes a fixed blade 35. 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 moving blade holder 38. The two ends of the wire cutting connecting rod 37 are respectively hinged to the wire cutting crank 36 and the moving blade holder 38. The moving blade 31 is fixed on the moving blade holder 38.

[0093] Preferably, such as Figure 1 and Figure 2 As shown, the wire cutting mechanism 30 also includes a return torsion spring 39 sleeved on the wire cutting shaft 32. The two ends of the return torsion spring 39 are connected to the integrated mounting base 40 and the wire cutting crank 36, respectively. After wire cutting is completed, the drive motor 11 rotates in the reverse direction, driving the feeding arm 231 from the end angle of the wire cutting working area X2. Reversing to the current angle within the feeding work area X1 before wire cutting, the wire cutting crank 36 is driven to reset under the action of the reset torsion spring 39, which in turn drives the wire cutting shaft 32, wire cutting connecting rod 37, moving blade holder 38, and other components to reset respectively; furthermore, when wire cutting is not required, the reset torsion spring 39 also keeps the wire cutting crank 36 in its initial position. More preferably, as Figure 5 and Figure 6As shown, the reset arm 342 extends from the cutting thread driving member 34, and is distributed in a circumferential direction with the cutting thread driving arm 341. The outer circumferential surface of the reset arm 342 has a forced reset surface. When the driving motor 11 drives the feeding arm 231 to start reversing from the end point angle of the cutting thread working area X2 When starting reversing, the forced reset surface on the reset arm 342 is in contact with the cutting thread ball 33, the cutting thread ball 33 pushes the reset arm 342 to reset, and further drives the cutting thread driving member 34 to reset forcibly, so as to reset the components in the cutting thread mechanism 30 forcibly, avoid the risk that the moving cutter 31 cannot reset smoothly due to being stuck by thread fluff, ensure that the moving cutter 31 can get rid of the fault position of being stuck by thread fluff, and ensure that the next time the thread can be cut smoothly and automatically.

[0094] Further, the position angle of the feeding arm 231 and the feeding connecting rod 24 is configured as follows, so as to realize that the moving distance of the feeding tooth 22 in the front-back direction during the cutting thread process is as small as possible, so as to realize the effect of cutting short thread, and improve the experience of customers. As shown in the figure, Figure 8 As shown, taking 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 to draw a circle O1, the point C is the center of the motor shaft of the driving motor 11, and the point D is the rotation center of the feeding arm 231 and the feeding connecting rod 24. Taking the hinge point B of the feeding connecting rod 24 and the driving crank 23 as the center and the effective length BD of the feeding connecting rod 24 as the radius to draw a circle O2, and the point A is the center of the feeding shaft 25. The circle O1 and the circle O2 are basically coincident within the ±β angle range on both sides of the collinear position of the feeding arm 231 and the feeding connecting rod 24. It is noted that the angle of the feeding arm 231 when the feeding arm 231 and the feeding connecting rod 24 are collinear is Therefore, the feeding arm 231 moves within the range of In this range, the feeding crank 26 basically remains unchanged, that is, the displacement of the feeding tooth 22 in the front-back direction is very small, and basically no feeding is performed. That is, when the angle of the feeding arm 231 is within the range of In this range, the feeding cutting thread mechanism makes the sewing machine have a small needle spacing; in the embodiment, when the angle of the feeding arm 231 is within the range of In this range, the feeding cutting thread mechanism makes the moving amount of the feeding tooth 22 in the front-back direction not more than 1 mm. Based on this, the cutting thread working area X2 of the feeding arm 231 is set within the range of In this range, the moving distance of the feeding tooth 22 in the front-back direction during the cutting thread process is very small; therefore, the cutting thread working area X2 of the feeding arm 231 can be set as In this way, the cutting thread working area X2 of the feeding arm 231 can have the following three embodiments.

[0095] The cutting thread working area X2 of the feeding arm 231 embodiment one, as shown in the figure, Figure 9a As shown,

[0096] Example 2: Wire cutting work area X2 of feeding arm 231 Figure 9b As shown,

[0097] Example 3: Wire cutting work area X2 of feeding arm 231 Figure 9c As shown,

[0098] Furthermore, when the feeding arm 231 and the feeding link 24 are collinear, the feeding tooth 22 is located at the front limit position within its reciprocating range, thus the feeding tooth 22 has a minimum limit distance with the front end of the tooth groove of the needle plate. Alternatively, when the feeding arm 231 and the feeding link 24 are collinear, the feeding tooth 22 is located at the rear limit position within its reciprocating range, thus the feeding tooth 22 has a minimum limit distance with the rear end of the tooth groove of the needle plate.

[0099] Furthermore, this application also provides a sewing machine, such as Figure 10 As shown, the sewing machine is equipped with the aforementioned feed and thread trimming mechanism. In addition, the sewing machine also includes a tooth-lifting drive source, a tooth-lifting mechanism 50, and a fixed base plate 60. The tooth-lifting mechanism 50 is driven between the tooth-lifting drive source and the tooth-lifting connection part 212 at the rear end of the tooth holder 21. The integrated mounting base 40 is detachably connected to the bottom of the sewing machine base plate 60. By installing and removing the integrated mounting base 40 in the sewing machine, the feed and thread trimming mechanism can be installed and removed as a whole. This allows the feed and thread trimming mechanism to be quickly adapted and installed as a separate functional mechanism in various sewing machine models without interfering with other functional mechanisms of the sewing machine, demonstrating strong compatibility.

[0100] Preferably, the integrated mounting base 40 and the base plate 60 are detachably connected by several screws, making assembly and disassembly convenient. For example... Figure 10 As shown, the feeding and thread-cutting mechanism is located on the left side of the base plate 60 near the sewing machine head.

[0101] Furthermore, such as Figure 11 or Figure 12 As shown, the tooth-lifting drive source is the main motor of the sewing machine. The tooth-lifting mechanism 50 includes a main shaft 51 driven to rotate by the main motor, a tooth-lifting shaft 52 parallel to the main shaft 51, a first tooth-lifting transmission assembly connected between the main shaft 51 and the tooth-lifting shaft 52, and a second tooth-lifting transmission assembly connected between the tooth-lifting shaft 52 and the tooth-lifting connecting part 212 of the tooth frame 21. Both the main shaft 51 and the tooth-lifting shaft 52 extend axially in the left-right direction.

[0102] When the feeding and cutting mechanism is compatible with the oscillating tooth lifting machine, such as Figure 11As shown, the first tooth lifting transmission assembly includes a tooth lifting eccentric wheel 53 fixed on the main shaft 51, a tooth lifting crank 54 fixed on the right end of the tooth lifting shaft 52, and a tooth lifting connecting rod 55, the upper end of the tooth lifting connecting rod 55 is rotatably sleeved on the outer periphery of the tooth lifting eccentric wheel 53, and the lower end of the tooth lifting connecting rod 55 is hinged with the tooth lifting crank 54; the second tooth lifting transmission assembly includes a tooth lifting fork crank 56 fixed on the left end of the tooth lifting shaft 52 and a tooth lifting slider 57 hinged with the tooth lifting connecting portion 212 of the tooth frame 21, and the tooth lifting fork crank 56 has a tooth lifting sliding groove in which the tooth lifting slider 57 is in sliding fit. The main motor drives the main shaft 51 to rotate, the main shaft 51 drives the tooth lifting shaft 52 to swing through the first tooth lifting transmission assembly, and the tooth lifting shaft 52 drives the tooth lifting fork crank 56 to swing up and down through the second tooth lifting transmission assembly, so as to realize the up-and-down reciprocating movement of the tooth frame 21 and the feeding tooth 22, and execute the tooth lifting action. The up-and-down tooth lifting action and the forward-and-backward feeding action of the feeding tooth 22 jointly constitute the feeding trajectory of the feeding tooth 22. Of course, in other embodiments, the second tooth lifting transmission assembly can adopt other structures of transmission pair.

[0103] When the feeding shear line mechanism is matched with the rotary tooth lifting machine type, as shown in Figure 12 As shown, the first tooth lifting transmission assembly includes a tooth lifting eccentric wheel 53 fixed on the main shaft 51, a tooth lifting crank 54 fixed on the right end of the tooth lifting shaft 52, and a tooth lifting connecting rod 55, the upper end of the tooth lifting connecting rod 55 is rotatably sleeved on the outer periphery of the tooth lifting eccentric wheel 53, and the lower end of the tooth lifting connecting rod 55 is hinged with the tooth lifting crank 54; the second tooth lifting transmission assembly includes a tooth lifting fork crank 56 fixed on the left end of the tooth lifting shaft 52 and a tooth lifting slider 57 hinged with the tooth lifting connecting portion 212 of the tooth frame 21, and the tooth lifting fork crank 56 has a tooth lifting sliding groove in which the tooth lifting slider 57 is in sliding fit. The main motor drives the main shaft 51 to rotate, the main shaft 51 drives the tooth lifting shaft 52 to swing through the first tooth lifting transmission assembly, and the tooth lifting shaft 52 drives the tooth lifting fork crank 56 to swing up and down through the second tooth lifting transmission assembly, so as to realize the up-and-down reciprocating movement of the tooth frame 21 and the feeding tooth 22, and execute the tooth lifting action. The up-and-down tooth lifting action and the forward-and-backward feeding action of the feeding tooth 22 jointly constitute the feeding trajectory of the feeding tooth 22. Of course, in other embodiments, the second tooth lifting transmission assembly can adopt other structures of transmission pair.

[0104] In summary, the present application effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0105] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A feeding and cutting mechanism based on long connecting rod and short crank structure, characterized in that: The feeding and thread cutting driving source (10), the feeding mechanism (20) and the thread cutting mechanism (30); The feeding mechanism (20) comprises a rack (21), feeding teeth (22) fixed on the rack (21), a driving crank (23) driven to rotate by the feeding and thread cutting driving source (10), a feeding arm (231) extending from the driving crank (23), a feeding connecting rod (24), a feeding shaft (25) rotatable about its own axis, a feeding crank (26) fixed on one end of the feeding shaft (25), and a rack seat (27) fixed on the other end of the feeding shaft (25), one end of the rack (21) is provided with a feeding connecting part (211), the two ends of the feeding connecting rod (24) are rotatably connected with the feeding arm (231) and the feeding crank (26) respectively, the rack seat (27) is connected with the feeding connecting part (211) of the rack (21), and the effective length of the feeding arm (231) is less than that of the feeding connecting rod (24). The thread cutting mechanism (30) comprises a movable knife (31) and a thread cutting transmission unit, the thread cutting transmission unit comprises a thread cutting arm (232) driven to rotate by the feeding and thread cutting driving source (10), a thread cutting clutch assembly, a thread cutting shaft (32) extending in left and right axial directions, and a thread cutting transmission assembly, the thread cutting arm (232) is in transmission connection with the thread cutting shaft (32) through the thread cutting clutch assembly, and the thread cutting shaft (32) is in transmission connection with the movable knife (31) through the thread cutting transmission assembly. When the feeding arm (231) is collinear with the feeding connecting rod (24), the angle of the feeding arm (231) is φ0; when the angle of the feeding arm (231) is within the range of φ0±β, the feeding and thread cutting mechanism enables the sewing machine to have a small needle distance. During the rotation of the driving crank (23) driven by the feeding and thread cutting driving source (10), the angle of the feeding arm (231) has a feeding working area (X1) and a thread cutting working area (X2), the feeding working area (X1) and the thread cutting working area (X2) are independent of each other, and the thread cutting working area (X2) of the feeding arm (231) is arranged within the range of φ0±β.

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

3. The feed and severing mechanism of claim 1, wherein: The integrated mounting base (40) is provided, the feeding and thread cutting driving source (10) is independent of the remaining driving sources in the sewing machine, and the feeding and thread cutting driving source (10), the feeding mechanism (20) and the thread cutting mechanism (30) are all mounted on the integrated mounting base (40).

4. The feed and severing mechanism of claim 3, wherein: The integrated mounting base (40) has a feeding support part (43), the feeding shaft (25) is rotatably supported in the feeding support part (43) of the integrated mounting base (40), and the feeding crank (26) and the rack seat (27) are distributed along the axial direction of the feeding shaft (25).

5. The feed and severing mechanism of claim 1, wherein: When the angle of the feeding arm (231) is within the range of φ0±β, the feeding and thread cutting mechanism enables the feeding teeth (22) to move in the front and back directions by not more than 1 mm.

6. The feed and severing mechanism of claim 1, wherein: When the feeding arm (231) is collinear with the feeding connecting rod (24), the feeding tooth (22) is located at the front limit position or the rear limit position in the front and rear reciprocating range thereof.

7. A sewing machine characterized by: The sewing machine is provided with the feeding and thread trimming mechanism according to any one of claims 1-6.

8. The sewing machine of claim 7, wherein: The lifting tooth driving source and a lifting tooth mechanism (50) are further included, and the other end of the tooth frame (21) is provided with a lifting tooth connecting portion (212), and the lifting tooth mechanism (50) is drivingly connected between the lifting tooth driving source and the lifting tooth connecting portion (212) of the tooth frame (21).

9. The sewing machine of claim 8, wherein: The lifting tooth driving source is a main motor of the sewing machine, and 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 tooth frame (21).

10. The sewing machine of claim 9, wherein: The first lifting tooth transmission assembly includes a lifting tooth eccentric wheel (53) fixed on the main shaft (51), a lifting tooth crank (54) fixed on one end of the lifting tooth shaft (52), and a lifting tooth connecting rod (55), one end of the lifting tooth connecting rod (55) being rotatably sleeved on the outer periphery of the lifting tooth eccentric wheel (53), and the other end of the lifting tooth connecting rod (55) being hingedly connected with the lifting tooth crank (54); and the second lifting tooth transmission assembly includes a lifting tooth fork crank (56) fixed on the other end of the lifting tooth shaft (52) and a lifting tooth sliding block (57) hingedly connected with the lifting tooth connecting portion (212) of the tooth frame (21), the lifting tooth fork crank (56) having a lifting tooth sliding groove slidingly matched with the lifting tooth sliding block (57).

11. The sewing machine of claim 9, wherein: The first lifting tooth transmission assembly includes a driving belt pulley (58) fixed on the main shaft (51), a driven belt pulley (59) fixed on one end of the lifting tooth shaft (52), and a transmission belt (510) connected on the outer peripheries of the driving belt pulley (58) and the driven belt pulley (59); and the second lifting tooth transmission assembly includes a lifting tooth eccentric wheel (53) fixed on 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) being rotatably sleeved on the outer periphery of the lifting tooth eccentric wheel (53), and the other end of the lifting tooth connecting rod (55) being hingedly connected with the lifting tooth connecting portion (212) of the tooth frame (21).

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