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

Abstract

The application provides a feeding and thread cutting mechanism based on a short connecting rod and 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, feeding teeth, 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, a rack seat fixed on the feeding shaft and a feeding connecting arm fixedly connected with the rack seat. Two ends of the feeding connecting rod are hingedly connected with the feeding arm and the feeding connecting arm respectively. The rack seat is connected with the rack. The effective length of the feeding arm is greater than that of the feeding connecting rod. The thread cutting mechanism comprises a movable moving knife and a thread cutting transmission unit in transmission connection between the feeding and thread cutting driving source and the moving knife. The transmission chain between the rack and the feeding and thread cutting driving source is short, the overall structure is simple and compact, and the stability is good. The space occupied is small, and interference with the layout and installation of other functional mechanisms in the sewing machine is avoided.

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 short connecting rod and long 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 assembly 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 assembly is still driven by the thread cutting cam on the lower shaft to rotate 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 step motor and the moving knife and the span between the step motor and the presser foot are large, resulting in a long overall transmission chain of the sewing machine, which occupies most of the installation space of the bottom plate and causes interference to the arrangement and installation of other transmission structures of 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 step motor to rotate the swing seat to different position angles, and different position angles of the swing seat correspond to different stitch sizes. Meanwhile, the step motor also drives the thread cutting fork wheel and other thread cutting components to operate and perform thread cutting actions. However, the sewing machine with this structure has many parts, a long transmission chain, poor structural stability, and complicated stitch adjustment and thread driving transmission. In addition, it 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 difficulty in implementation; 2. Long transmission chain, resulting in the transmission structure including the step motor occupying most of the installation space of the machine and causing interference to the arrangement and installation of other structures; 3. Single function, the power of the thread cutting mechanism still depends on the main shaft or the main motor, and the power source configured in the thread cutting mechanism can only switch the 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 a short connecting rod and long 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 a short connecting rod and long 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 tooth frame, feeding teeth fixed on the tooth frame, a driving crank driven to rotate by the feeding and thread cutting driving source, a feeding arm extending from the driving crank, a feeding connecting rod, a feeding shaft rotatable about its own axis, a tooth frame seat fixed on the feeding shaft, and a feeding connecting arm fixedly connected with the tooth frame seat. The two ends of the feeding connecting rod are hingedly connected with the feeding arm and the feeding connecting arm, respectively. The tooth frame seat is connected with the feeding connection part of the tooth frame. The effective length of the feeding arm is greater than the effective length of the feeding connecting rod.

[0011] The thread trimming mechanism comprises a movable knife, and a thread trimming transmission unit connected in transmission between the thread trimming driving source and the movable knife.

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

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

[0014] Further, the thread trimming driving source is connected with the thread trimming transmission unit through the driving crank.

[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 thread trimming 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 thread trimming mechanism enables the feeding teeth (22) to move in the front and back directions by an amount of not more than 1 mm.

[0017] Further, when the feeding arm is collinear with the feeding connecting rod, the feeding teeth are 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 thread trimming 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 tooth bar is provided with a tooth lifting connecting portion, and the tooth lifting mechanism is connected in transmission between the tooth lifting driving source and the tooth lifting connecting portion of the tooth bar.

[0020] Further, the tooth lifting driving source is a main motor of the sewing machine, the tooth lifting mechanism comprises a main shaft driven to rotate by the main motor, a tooth lifting shaft parallel to the main shaft, a first tooth lifting transmission assembly connected between the main shaft and the tooth lifting shaft, and a second tooth lifting transmission assembly connected between the tooth lifting shaft and the tooth lifting connecting portion of the tooth bar.

[0021] Further, the first tooth lifting transmission assembly comprises a tooth lifting eccentric wheel fixed on the main shaft, a tooth lifting crank fixed on one end of the tooth lifting shaft, and a tooth lifting connecting rod, one end of the tooth lifting connecting rod is rotatably sleeved on the outer periphery of the tooth lifting eccentric wheel, and the other end of the tooth lifting connecting rod is hinged with the tooth lifting crank; the second tooth lifting transmission assembly comprises a tooth lifting fork crank fixed on the other end of the tooth lifting shaft, and a tooth lifting slider hinged with the tooth lifting connecting portion of the tooth frame.

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

[0023] As described above, the feeding and cutting thread mechanism based on the short connecting rod and long 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 thread driving source, the transmission chain between the tooth frame and the feeding and cutting thread 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 It is a structural schematic diagram of the feeding and cutting thread mechanism in the present application.

[0026] Figure 2 It is a left view. Figure 1

[0027] Figure 3 It is a connection schematic diagram between the feeding and cutting thread driving source and the feeding mechanism in the feeding and cutting thread mechanism.

[0028] Figure 4 It is a connection schematic diagram between the feeding and cutting thread driving source and the cutting thread mechanism in the feeding and cutting thread mechanism.

[0029] Figure 5 It is a distribution schematic diagram of the working area of the feeding arm in the feeding and cutting thread mechanism.

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

[0031] Figures 7a to 7d It is a schematic diagram of the four kinds of motion trajectories of the feeding tooth in the feeding and cutting thread mechanism.​

[0032] Figure 8 Figure 7 is a position diagram of the feeding arm and the feeding connecting rod in the feeding and thread cutting mechanism.

[0033] Figures 9a to 9c Figure 8 is a diagram of three kinds of distribution of the thread cutting working area of the feeding arm in the feeding and thread cutting mechanism.

[0034] Figure 10 Figure 9 is a structural diagram of the first embodiment of the sewing machine in the present application.

[0035] Figure 11 Figure 10 is a structural diagram of the second embodiment of the sewing machine in the present application.

[0036] Element number explanation

[0037] 10 feeding and thread cutting driving source

[0038] 11 driving motor

[0039] 20 feeding mechanism

[0040] 21 tooth rack

[0041] 211 feeding connecting part

[0042] 212 tooth rack connecting part

[0043] 22 feeding tooth

[0044] 23 driving crank

[0045] 231 feeding arm

[0046] 232 thread cutting arm

[0047] 24 feeding connecting rod

[0048] 25 feeding shaft

[0049] 26 tooth rack seat

[0050] 261 feeding connecting arm

[0051] 30 thread cutting mechanism

[0052] 31 moving cutter

[0053] 32 thread cutting shaft

[0054] 33 thread cutting ball

[0055] 34 thread cutting driving part

[0056] 341 thread cutting driving arm

[0057] 342 thread cutting connecting arm

[0058] 343 Reset Arm

[0059] 36 Wire-cutting connecting rod

[0060] 37. Moving tool holder

[0061] 40 Tooth Lifting Mechanism

[0062] 41 Spindle

[0063] 42 Tooth lifting shaft

[0064] 43. Eccentric tooth lifting wheel

[0065] 44. Crank handle for lifting teeth

[0066] 45. Tooth-lifting linkage

[0067] 46. ​​Lifting tooth fork-shaped crank

[0068] 47. Tooth-lifting slider

[0069] 48. Drive pulley

[0070] 49 Driven pulley

[0071] 410 Transmission Belt

[0072] 50 base plate

[0073] 60 Integrated mounting base Detailed Implementation

[0074] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0075] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0076] The present application provides a feeding and thread cutting mechanism based on a short connecting rod and long crank structure, and a sewing machine comprising the feeding and thread 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 sewing machine head is the left direction, and the direction towards the sewing machine tail is the right direction, so the left-right direction is also the axial direction of the main shaft 41 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.

[0077] As shown in Figures 1 to 3 , the feeding and thread cutting mechanism based on the short connecting rod and long crank structure 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 tooth holder 21, feeding teeth 22 fixed on the upper end surface of the tooth holder 21, a driving crank 23 driven to rotate by the feeding and thread cutting driving source 10, a feeding arm 231 integrally extended from the driving crank 23, a feeding connecting rod 24, a feeding shaft 25 rotatable about its own axis and extending in the left-right axial direction, a tooth holder seat 26 fixed on the feeding shaft 25, and a feeding connecting arm 261 fixedly connected with the tooth holder seat 26, the front end of the tooth holder 21 is a feeding connecting part 211, the rear end of the tooth holder 21 is a tooth lifting connecting part 212, the two ends of the feeding connecting rod 24 are respectively hingedly connected with the feeding arm 231 and the feeding connecting arm 261, the tooth holder seat 26 is connected with the feeding connecting part 211 at the front end of the tooth holder 21, and the effective length of the feeding arm 231 is greater than the effective length of the feeding connecting rod 24; the thread cutting mechanism 30 comprises a movable cutter 31 and a thread cutting transmission unit in transmission connection 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 feeding connecting arm 261; that is, the structure of long crank and short connecting rod is adopted. In this embodiment, the rotation connection between one end of the feeding connecting rod 24 and the feeding arm 231 and the rotation connection between the other end of the feeding connecting rod 24 and the feeding connecting arm 261 are both realized by the left-right axial extension of the pin and the bearing, that is, hinged connection, and the bearing is assembled between the pin and the end of the feeding connecting rod 24.

[0078] In the process of driving the driving crank 23 to rotate by the feeding and thread cutting driving source 10, the feeding arm 231 of the driving crank 23 rotates synchronously; as shown in Figure 5 , the angle of the feeding arm 231 has a feeding working area X1, and the two end angles of the feeding working area X1 are and When the feeding arm 231 operates in the feeding working area X1, the feeding arm 231 directly drives the swing of the rack seat 26 through the feeding connecting rod 24, and then drives the forward and backward reciprocating movement of the rack 21, and the feeding teeth 22 synchronously move forward and backward with the rack 21 to perform the feeding action. When the thread needs to be cut, the thread cutting driving source drives the moving knife 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 involved in the present application has the functions of feeding and automatic thread cutting; the power of the rack 21 in the feeding mechanism 20 directly comes from the feeding and thread cutting driving source 10, so that the transmission chain between the rack 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.

[0079] Preferably, the feeding connecting arm 261 and the rack seat 26 can be an integral structure, that is, the outer periphery of the rack seat 26 is integrally provided with the feeding connecting arm 261; or the feeding connecting arm 261 and the rack seat 26 are separate parts, and are fixedly connected through screws. In the embodiment, the feeding connecting arm 261 integrally extends from the rack seat 26.

[0080] 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 thread cutting driving source 10, the swing range of the feeding arm 231 in the feeding working area X1 is adjusted, and then the size of the effective stitch length of the sewing machine is adjusted, the adjustment of the feeding stitch length is realized, and the motion trajectory of the feeding teeth 22 is adjusted. For example, the feeding teeth 22 can have an elliptical motion trajectory as shown in Figure 7a , or the feeding teeth 22 can have a nearly vertical motion trajectory as shown in Figure 7b , or the feeding teeth 22 can have a far vertical motion trajectory as shown in Figure 7c , or the feeding teeth 22 can have a rectangular motion trajectory as shown in Figure 7d . In this way, the feeding and thread cutting mechanism has the functions of step adjustment of stitch length, reverse sewing switching, feeding trajectory switching, pattern sewing, etc.

[0081] Further, as shown in Figure 10 or Figure 11As shown, the feeding and thread trimming mechanism further comprises an integrated mounting base 60, the feeding and thread trimming driving source 10 is independent of the rest driving sources in the sewing machine, the feeding and thread trimming driving source 10, the feeding mechanism 20 and the thread trimming mechanism 30 are all mounted on the integrated mounting base 60, and the feeding shaft 25 is rotatably supported in the integrated mounting base 60 through bearings, shaft sleeves and other components. In this way, the feeding and thread trimming driving source 10, the feeding mechanism 20, the thread trimming mechanism 30 and the integrated mounting base 60 are integrated into one independent functional module, and the feeding mechanism 20 and the thread trimming mechanism 30 are modularized independently, so that the feeding and thread trimming mechanism is an independent feeding and thread trimming module, which is independent of other functional mechanisms in the sewing machine. After adopting the independent modular structure, the installation and dismounting of the integrated mounting base 60 in the sewing machine realizes the installation and dismounting of the independent feeding and thread trimming module as a whole in the sewing machine, and realizes the quick adaptation and installation of the independent feeding and thread trimming module in various types of sewing machines, which has strong compatibility, that is, a novel design platform of the sewing machine is developed.

[0082] Preferably, as shown in the drawings, Figures 1 to 3 The feeding and thread trimming driving source 10 is a driving motor 11, and the driving crank 23 is fixed on the motor shaft of the driving motor 11 through screws and 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.

[0083] Further, as shown in the drawings, Figure 1 , Figure 2 and Figure 4As shown, the feeding and thread-cutting driving source 10 is connected with the thread-cutting transmission unit through the driving crank 23; preferably, the feeding arm 231 is coaxial with the connecting point of the driving crank 23 and the thread-cutting transmission unit. Specifically, 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, left and right axially extending thread-cutting shafts 32, and a thread-cutting transmission assembly; the thread-cutting clutch assembly comprises thread-cutting balls 33 and thread-cutting driving members 34 fixed on the thread-cutting shafts 32, and the thread-cutting driving members 34 integrally extend with thread-cutting driving arms 341; the thread-cutting balls 33 are rotatably installed on the thread-cutting arm 232, and the thread-cutting driving arms 341 are provided with thread-cutting sliding groove surfaces, or the thread-cutting balls 33 are rotatably installed on the thread-cutting driving arms 341, and the thread-cutting arm 232 is provided with thread-cutting sliding groove surfaces; in this embodiment, the thread-cutting balls 33 are rotatably installed on the thread-cutting arm 232, the outer circumferential surface of the thread-cutting driving arm 341 has a thread-cutting sliding groove surface, and the thread-cutting transmission assembly is drivingly connected between the thread-cutting shafts 32 and the moving knife 31. The thread-cutting arm 232 and the driving crank 23 are both driven to rotate by the feeding and thread-cutting driving source 10, and the thread-cutting arm 232 and the driving crank 23 can be separate parts, both fixed on the motor shaft of the feeding and thread-cutting driving source 10 by screws, or the thread-cutting arm 232 is fixed on the driving crank 23; in this embodiment, the thread-cutting arm 232 integrally extends from the outer periphery of the driving crank 23, and the thread-cutting arm 232 and the feeding arm 231 on the driving crank 23 are a same arm part, the outer end of the common arm part, the feeding connecting rod 24 and the thread-cutting balls 33 are coaxially connected by a left and right extending pin, the feeding connecting rod 24 is distributed on the left side of the common arm part, and the thread-cutting balls 33 are distributed on the right side of the common arm part. The thread-cutting mechanism 30 is a single-moving-knife structure; based on this, the thread-cutting mechanism 30 further comprises a fixed knife, the thread-cutting driving members 34 extend with thread-cutting connecting arms 342, the thread-cutting driving arms 341 and the thread-cutting connecting arms 342 are distributed in a circumferential direction, the thread-cutting transmission assembly comprises thread-cutting connecting rods 36 and a rotatable moving knife holder 37, the two ends of the thread-cutting connecting rods 36 are respectively hingedly connected with the thread-cutting connecting arms 342 and the moving knife holder 37, and the moving knife 31 is fixed on the moving knife holder 37. Of course, in other embodiments, the thread-cutting mechanism 30 can also adopt a double-moving-knife 31 structure.

[0084] Further, as shown, Figure 5 in the process of driving the driving crank 23 to rotate by the driving motor 11, the angle of the feeding arm 231 also has 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 angles of the two ends of the thread-cutting working area X2 are and in the forward rotation direction of the driving motor 11 during thread cutting of the sewing machine, In this way, the angle range of the feeding working area X1 of the feeding arm 231 is and the angle range of the thread-cutting working area X2 of the feeding arm 231 is The angle of the feeding arm 231 also has an idle area X3 distributed between the feeding work area X1 and the shearing line work area X2, and the angle range of the idle area X3 of the feeding arm 231 is

[0085] When the feeding arm 231 operates in the feeding work area X1, the feeding teeth 22 normally feed, at this time, the shearing line ball 33 is separated from the shearing line sliding groove surface on the shearing line driving arm 341, so that the shearing line clutch assembly is in a separated state and does not transmit power, the shearing line transmission unit does not transmit power, and the shearing line mechanism 30 does not perform the shearing line action. When shearing line is needed, the driving motor 11 drives the feeding arm 231 to forward rotate from the current angle in the feeding work area X1 to the starting angle of the shearing line work area X2 After forward rotating to the end angle of the shearing line work area X2 During the process of forward rotating from to , the feeding arm 231 operates in the shearing line work area X2, the shearing line ball 33 gradually approaches the shearing line sliding groove surface of the shearing line driving arm 341 until contact, as shown in Figure 6 , so that the shearing line clutch assembly is in an engaged state and transmits power, and then the feeding arm 231 pushes the shearing line driving member 34 through the contact and cooperation of the shearing line ball 33 and the shearing line sliding groove surface of the shearing line driving arm 341, and drives the moving knife 31 to move through the shearing line connecting rod 36 and the knife holder 37, so that the shearing line mechanism 30 performs automatic shearing line. In this way, the feeding and shearing line mechanism realizes the driving of feeding and shearing line by using the same driving motor 11, and the feeding driving and the shearing line driving do not conflict with each other.

[0086] Further, the shearing line mechanism 30 also includes a reset torsion spring sleeved on the shearing line shaft 32, and the two ends of the reset torsion spring are connected with the integrated installation base 60 and the shearing line connecting arm 342 respectively. After the shearing line is finished, the driving motor 11 reversely rotates to drive the feeding arm 231 to reverse from the end angle of the shearing line work area X2 to the current angle in the feeding work area X1 before shearing line, and under the action of the reset torsion spring, the shearing line driving member 34 is reversely rotated to reset, so that the shearing line shaft 32, the shearing line connecting rod 36, the knife holder 37 and other components are respectively reset; and when the shearing line is not needed, the reset torsion spring also keeps the shearing line driving member 34 in the initial position. More preferably, as shown in Figure 6 , the shearing line driving member 34 also extends the reset arm 343, the reset arm 343 is distributed in the circumferential direction of the shearing line driving arm 341, the outer circumferential surface of the reset arm 343 has a forced reset surface; and when the driving motor 11 drives the feeding arm 231 to reverse from the end angle of the shearing line work area X2 When the reversing starts, the forced reset surface on the reset arm 343 is in contact with the thread trimming ball 33, the thread trimming ball 33 pushes the reset arm 343 to reset, and in turn drives the thread trimming driving member 34 to force reset, so as to force reset each component in the thread trimming mechanism 30, avoid the risk that the moving knife 31 cannot be reset smoothly due to being stuck by thread fluff, ensure that the moving knife 31 can get rid of the fault position of being stuck by thread fluff, and ensure that the thread trimming can be performed smoothly next time.

[0087] 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 thread trimming process is as small as possible, thereby realizing the thread trimming effect of short thread, and improving the experience of customers. Specifically, as shown in Figure 8 , a circle O3 is drawn with the rotation center E of the feeding arm 231 as the center and with the effective length EF of the feeding arm 231 as the radius, then the point E is the center of the motor shaft of the driving motor 11, and the point F is the rotation center of the feeding arm 231 and the feeding connecting rod 24; a circle O4 is drawn with the hinge point G of the feeding connecting rod 24 and the feeding connecting arm 261 as the center and with the effective length FG of the feeding connecting rod 24 as the radius. The circle O3 and the circle O4 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 recorded that the angle of the feeding arm 231 when the feeding arm 231 and the feeding connecting rod 24 are collinear is , and the feeding arm 231 moves within the range of , the four-bar mechanism composed of the driving crank 23, the feeding connecting rod 24, the tooth holder seat 26 and the tooth holder 21 forms an intermittent mechanism, a pause period is generated, the position of the hinge point of the feeding connecting arm 261 of the feeding connecting rod 24 and the tooth holder seat 26 changes little, the position angle of the tooth holder seat 26 changes little, and the tooth holder seat 26 basically remains stationary, so that 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 , the sewing machine has a small needle spacing; in the embodiment, when the angle of the feeding arm 231 is within the range of , the feeding and thread trimming mechanism makes the moving amount of the feeding tooth 22 in the front-back direction not more than 1 mm. Based on this, the thread trimming working area X2 of the feeding arm 231 is set within the range of , so that the moving distance of the feeding tooth 22 in the front-back direction during the thread trimming process is very small; and the thread trimming working area X2 of the feeding arm 231 can be set as In this way, the thread trimming working area X2 of the feeding arm 231 can have the following three embodiments.

[0088] Embodiment one of the thread trimming working area X2 of the feeding arm 231, as shown in Figure 9a , the thread trimming working area X2 of the feeding arm 231 is set within the range of

[0089] Embodiment two of the thread trimming working area X2 of the feeding arm 231, as shown inFigure 9b as shown,

[0090] The third embodiment of the thread trimming work area X2 of the feeding arm 231 is shown in Figure 9c as shown,

[0091] Further, when the feeding arm 231 is collinear with the feeding link 24, the feeding tooth 22 is at the front limit position in its reciprocating range, and the feeding tooth 22 has the minimum limit distance with the front end of the tooth groove of the needle plate. Alternatively, when the feeding arm 231 is collinear with the feeding link 24, the feeding tooth 22 is at the rear limit position in its reciprocating range, and the feeding tooth 22 has the minimum limit distance with the rear end of the tooth groove of the needle plate.

[0092] Further, the present application also provides a sewing machine, as shown in Figure 10 or Figure 11 The feeding and thread trimming mechanism is arranged in the sewing machine. In addition, the sewing machine also includes a lifting tooth driving source, a lifting tooth mechanism 40, and a fixedly arranged bottom plate 50. The lifting tooth mechanism 40 is drivingly connected between the lifting tooth driving source and the lifting tooth connecting portion 212 at the rear end of the tooth holder 21. The integrated mounting base 60 is detachably connected to the bottom of the bottom plate 50 of the sewing machine. Through the mounting and dismounting of the integrated mounting base 60 in the sewing machine, the mounting and dismounting of the feeding and thread trimming mechanism in the sewing machine is realized, and the feeding and thread trimming mechanism is quickly adapted and mounted in various models of sewing machines as a separate functional mechanism without interfering with other functional mechanisms of the sewing machine, and has strong compatibility.

[0093] Preferably, the integrated mounting base 60 is detachably connected to the bottom plate 50 by a plurality of screws, which is convenient to dismount. As shown in Figure 10 or Figure 11 The feeding and thread trimming mechanism is distributed on the left side of the bottom plate 50 close to the head of the sewing machine.

[0094] Further, as shown in Figure 10 or Figure 11 The lifting tooth driving source is the main motor of the sewing machine, and the lifting tooth mechanism 40 includes a main shaft 41 driven to rotate by the main motor, a lifting tooth shaft 42 parallel to the main shaft 41, a first lifting tooth transmission assembly connected between the main shaft 41 and the lifting tooth shaft 42, and a second lifting tooth transmission assembly connected between the lifting tooth shaft 42 and the lifting tooth connecting portion 212 of the tooth holder 21. The main shaft 41 and the lifting tooth shaft 42 both extend axially in the left-right direction.

[0095] When the feeding and thread trimming mechanism is adapted to the swing type lifting tooth machine, as shown in Figure 10As shown, the first tooth lifting transmission assembly includes a tooth lifting eccentric wheel 43 fixed on the main shaft 41, a tooth lifting crank 44 fixed on the right end of the tooth lifting shaft 42, and a tooth lifting connecting rod 45, the upper end of the tooth lifting connecting rod 45 is rotatably sleeved on the outer periphery of the tooth lifting eccentric wheel 43, and the lower end of the tooth lifting connecting rod 45 is hinged with the tooth lifting crank 44; the second tooth lifting transmission assembly includes a tooth lifting fork crank 46 fixed on the left end of the tooth lifting shaft 42 and a tooth lifting slider 47 hinged with the tooth lifting connecting portion 212 of the tooth frame 21, and the tooth lifting fork crank 46 has a tooth lifting sliding groove in which the tooth lifting slider 47 is in sliding fit. The main motor drives the main shaft 41 to rotate, the main shaft 41 drives the tooth lifting shaft 42 to swing through the first tooth lifting transmission assembly, and the tooth lifting shaft 42 drives the tooth lifting fork crank 46 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 perform 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.

[0096] When the feeding shearing line mechanism is matched with the rotary tooth lifting machine type, as shown in Figure 11 the first tooth lifting transmission assembly includes a driving pulley 48 fixed on the main shaft 41, a driven pulley 49 fixed on the right end of the tooth lifting shaft 42, and a transmission belt 410 connected on the outer periphery of the driving pulley 48 and the driven pulley 49, and the rotation speed ratio of the driving pulley 48 and the driven pulley 49 is 1:1; the second tooth lifting transmission assembly includes a tooth lifting eccentric wheel 43 fixed on the left end of the tooth lifting shaft 42 and a tooth lifting connecting rod 45, one end of the tooth lifting connecting rod 45 is rotatably sleeved on the outer periphery of the tooth lifting eccentric wheel 43, and the other end of the tooth lifting connecting rod 45 is hinged with the tooth lifting connecting portion 212 of the tooth frame 21. The main motor drives the main shaft 41 to rotate, the main shaft 41 drives the tooth lifting shaft 42 to rotate through the first tooth lifting transmission assembly, and the tooth lifting shaft 42 drives the tooth frame 21 and the feeding tooth 22 to reciprocate up and down through the second tooth lifting transmission assembly, and performs 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.

[0097] In summary, the present application effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0098] 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 short link length crank based feed and thread trimming mechanism characterized by: 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 rack seat (26) fixed on the feeding shaft (25), and a feeding connecting arm (261) fixedly connected with the rack seat (26), both ends of the feeding connecting rod (24) are hingedly connected with the feeding arm (231) and the feeding connecting arm (261) respectively, the rack seat (26) is connected with a feeding connecting part (211) of the rack (21), and the effective length of the feeding arm (231) is greater than the effective length 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, left and right axially extending thread cutting shafts (32) and a thread cutting transmission assembly, the thread cutting arm (232) is in transmission connection with the thread cutting shafts (32) through the thread cutting clutch assembly, and the thread cutting shafts (32) are 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 pitch. 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 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 (60).

4. The feed and severing mechanism of claim 1, wherein: The feeding and thread cutting driving source (10) is connected with the thread cutting transmission unit through the driving crank (23).

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 an amount of 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 teeth (22) are located at the front limit position or the rear limit position in the front and back reciprocating movement range.

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

8. The sewing machine of claim 7, wherein: The dental frame (21) is provided with a lifting tooth connecting part (212) at the other end, and a lifting tooth mechanism (40) is drivingly connected between the lifting tooth driving source and the lifting tooth connecting part (212) of the dental 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 (40) comprises a main shaft (41) driven to rotate by the main motor, a lifting tooth shaft (42) parallel to the main shaft (41), a first lifting tooth transmission assembly connected between the main shaft (41) and the lifting tooth shaft (42), and a second lifting tooth transmission assembly connected between the lifting tooth shaft (42) and the lifting tooth connecting part (212) of the dental frame (21).

10. The sewing machine of claim 9, wherein: The first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel (43) fixed on the main shaft (41), a lifting tooth crank (44) fixed on one end of the lifting tooth shaft (42), and a lifting tooth connecting rod (45), one end of the lifting tooth connecting rod (45) being rotatably sleeved on the outer periphery of the lifting tooth eccentric wheel (43), and the other end of the lifting tooth connecting rod (45) being hingedly connected with the lifting tooth crank (44); and the second lifting tooth transmission assembly comprises a lifting tooth fork crank (46) fixed on the other end of the lifting tooth shaft (42) and a lifting tooth sliding block (47) hingedly connected with the lifting tooth connecting part (212) of the dental frame (21), the lifting tooth fork crank (46) having a lifting tooth sliding groove therein in sliding fit with the lifting tooth sliding block (47).

11. The sewing machine of claim 9, wherein: The first lifting tooth transmission assembly comprises a driving belt pulley (48) fixed on the main shaft (41), a driven belt pulley (49) fixed on one end of the lifting tooth shaft (42), and a transmission belt (410) connected between the outer peripheries of the driving belt pulley (48) and the driven belt pulley (49); and the second lifting tooth transmission assembly comprises a lifting tooth eccentric wheel (43) fixed on the other end of the lifting tooth shaft (42) and a lifting tooth connecting rod (45), one end of the lifting tooth connecting rod (45) being rotatably sleeved on the outer periphery of the lifting tooth eccentric wheel (43), and the other end of the lifting tooth connecting rod (45) being hingedly connected with the lifting tooth connecting part (212) of the dental frame (21).

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