A feed dog drive mechanism for a sewing machine

Abstract

The present application provides a feed dog driving mechanism for a sewing machine, specifically relating to the technical field of sewing machine manufacturing. It has a lifting shaft and a feed shaft. It is characterized in that it also has a lifting motor, a feed motor, and a feed dog. The lifting motor is connected to and drives the lifting shaft, and the feed motor is connected to and drives the feed shaft. Under the control of the control system of the sewing machine, the purpose of indirectly realizing the feeding action of the feed dog by the lifting motor and the feed motor is achieved. The sewing machine of the present application removes the traditional component of the swing seat, but can fully possess the functions of the swing seat. At the same time, it breaks the design concept of traditional sewing machines and cancels the technology of the feed connecting rod and the lifting connecting rod connected and driven by a cam, making the manufacturing cost of the sewing machine reduced, the structure simple, and it is an efficient sewing machine without a lubrication system.

Description

Technical Field

[0001] The present application provides a feed dog driving mechanism for a sewing machine, specifically relating to the technical field of sewing machine manufacturing. Background Art

[0002] In the driving mechanism of a sewing machine, a main motor is installed on the head of the sewing machine. The main motor is connected to an output main shaft, and an eccentric wheel is fixedly installed on the output main shaft. The main motor operates to drive the feed link and the lifter link to move by the rotation of the eccentric wheel. The feed link drives the feed shaft to rotate at a certain angle through a swing seat assembly, and the lifter link drives the lifter shaft to swing at a certain angle through a lifter crank; the swing of the feed link and the feed shaft drives the feed dog holder to swing, thereby generating a forward and backward movement for the feed dog; the swing of the lifter link and the lifter shaft drives the lifter fork on the lifter shaft to swing, thereby causing the feed dog to generate an up and down movement. The combination of the forward and backward movement and the up and down movement forms the feeding action of the feed dog.

[0003] Regarding the swing seat for stitch pitch control, many enterprises have proposed intelligent control technical solutions for achieving the stitch pitch of the feed. There is a patent solution that has a feed shaft drive source, a connecting crank, a feed shaft, a feed dog holder, and a feed dog. It is characterized in that it also has a swing rod. The feed shaft drive source has an output shaft, and a swing rod is installed on the output shaft. The swing rod is hinged to the connecting crank, the connecting crank is fixed to the feed shaft, the feed shaft is movably connected to the feed dog holder, and the feed dog is fixed on the feed dog holder. In fact, this solution uses the feed shaft drive source to drive the swing rod to replace the original feed link of the sewing machine, implements stitch pitch adjustment for the stitch pitch adjustment mechanism and positions the zero point position of the feed dog for the zero position positioning mechanism, achieving a positive technical effect of stitch pitch adjustment. However, the movement of the lifter link still remains at the existing technology level, making the up and down feeding action of the feed dog unable to reach the intelligent control level.

[0004] In addition, a bevel gear is also fixedly installed on the output main shaft of the sewing machine. The bevel gear meshed with it is the bevel gear on the vertical shaft, and the vertical shaft is also meshed with the bevel gear on the lower shaft. A rotary hook is fixedly installed at the end of the lower shaft. Driven by the main motor, the lower shaft is driven to rotate through the vertical shaft, providing power for the operation of the rotary hook. Here, the transmission ratio between the lower shaft and the main shaft is usually set to 1:2, thus forming a unique technology that the rotary hook rotates two weeks when the sewing machine needle pierces the fabric once. However, these most commonly used components, including the above-mentioned swing seat, are vulnerable to wear and tear, requiring the guarantee of the sewing machine lubrication system, still generating relatively high noise during operation, and requiring frequent maintenance and replacement; in addition, due to the long lengths of the lower shaft and the vertical shaft, the manufacturing and assembly processes are more cumbersome and complex, and the manufacturing cost is also relatively high. Summary of the Invention

[0005] In view of the complex structure of existing sewing machine technologies and the need for a lubrication system, this application aims to achieve a feed dog drive mechanism for a sewing machine that is simple in structure and does not require lubrication to overcome the above-mentioned drawbacks. It has a lifter shaft and a feed shaft, and is characterized in that it also has a lifter motor, a feed motor, and a feed dog. The lifter motor is connected to and drives the lifter shaft, and the feed motor is connected to and drives the feed shaft. The lifter motor and the feed motor indirectly achieve the feeding action of the feed dog.

[0006] Preferably, it also has a bobbin winder motor. The bobbin winder motor is connected to and drives the lower shaft, enabling the bobbin winder connected to the lower shaft to perform the actions of taking up and hooking the thread. The bobbin winder motor drives the lower shaft to rotate in a rotational manner.

[0007] Preferably, it also has an upper shaft motor. The upper shaft motor is installed on one side, in the middle, or at the rear of the upper shaft near the needle bar. A fan is also configured at the rear of the upper shaft motor. A connecting rod is also connected to the rear of the upper shaft motor. The end of the connecting rod is fixedly connected to a handwheel for adjusting the position of the needle bar. The upper shaft motor drives the upper shaft to rotate in a rotational manner, and through a transmission member installed on the upper shaft that converts the rotational movement into the up-and-down movement of the needle bar, the threading action of the thread-carrying needle bar passing through the needle plate is achieved.

[0008] Preferably, the diameter of the connecting rod is smaller than that of the upper shaft.

[0009] Preferably, the bobbin winder motor is installed and fixed between the lifter motor and the feed motor, and the lifter motor is installed on the side of the sewing machine near the bobbin winder.

[0010] Preferably, the lifter motor and the feed motor are installed and fixed under the substrate. The lifter motor and the feed motor are located on both sides of the substrate, and the lifter motor and the feed motor are installed on the side of the sewing machine near the bobbin winder.

[0011] Preferably, the lifter shaft is directly connected to the output shaft of the lifter motor, or the lifter shaft and the output shaft of the lifter motor are integrated. A lifter fork-shaped crank is installed at the front end of the lifter shaft. The lifter fork-shaped crank cooperates with the movable shaft of the feed dog bracket. The lifter fork-shaped crank transmits the back-and-forth swinging action to the bracket under the drive of the lifter motor in a repeatedly back-and-forth swinging operation mode, enabling the feed dog to have a back-and-forth swinging action.

[0012] Preferably, the feed shaft is directly connected to the output shaft of the feed motor, or the feed shaft and the output shaft of the feed motor are integrated. A bracket seat is installed at the front end of the feed shaft. The bracket seat is connected to a bracket, and a feed dog is fixed on the bracket. The bracket seat and the bracket transmit the up-and-down swinging action to the bracket under the drive of the feed motor in a repeatedly back-and-forth swinging operation mode, enabling the feed dog to have an up-and-down swinging action.

[0013] Preferably, the cloth feed motor is mounted on the side body of the sewing machine, and the cloth feed shaft extends to the lower position of the cloth feed motor. A swing crank, a connecting rod and a cloth feed shaft crank are provided between the cloth feed motor and the cloth feed shaft. A swing crank is fixed on the output shaft of the cloth feed motor, and the swing crank is hinged with a connecting rod, which is hinged to the cloth feed shaft crank. The cloth feed shaft crank is fixed at the rear end of the cloth feed shaft. The cloth feed motor drives the lower tooth frame in a repeated back and forth swinging operation mode to transmit an up and down swinging motion, so that the feed dog has an up and down swinging motion.

[0014] Preferably, the device further comprises a presser foot lifting assembly and a thread trimming assembly, the presser foot lifting assembly comprising a thread trimming and presser foot lifting motor, a presser foot lifting cam, a presser foot lifting push rod and a presser foot lifting execution end, the presser foot lifting cam comprising a presser foot lifting cam lifting surface and an idling circular arc surface, the presser foot lifting cam being fixed to the output shaft of the thread trimming and presser foot lifting motor, the presser foot lifting cam lifting surface being used to adjust the presser foot lifting push rod from a lower or higher position to a higher or lower position, the idling circular arc surface being used for idling between the presser foot lifting push rod and the presser foot lifting cam, the idling circular arc surface being concentrically arranged with the output shaft of the thread trimming and presser foot lifting motor, and the presser foot lifting cam lifting surface being located at the cam portion of the presser foot lifting cam;

[0015] The thread trimming assembly comprises a thread trimming and presser foot lifting motor, a thread trimming crank, a thread trimming fork wheel and a thread trimming execution end. The thread trimming crank has a pushing member, which is arranged at an eccentric position of the thread trimming crank. The pushing member pushes the thread trimming fork wheel to perform the thread trimming action. The thread trimming fork wheel has a return rod and a thread trimming rod. The pushing member is located between the return rod and the thread trimming rod. When the thread trimming and presser foot lifting motor drives the thread trimming crank, the pushing member pushes the thread trimming rod so that the thread trimming execution end performs the thread trimming action.

[0016] After the thread trimming action is completed, the presser foot lifting cam starts to perform the presser foot lifting action. The rotation angle of the thread trimming and presser foot lifting motors during the thread trimming action will not cause the presser foot lifting cam to produce an actual presser foot lifting action on the presser foot lifting push rod. The presser foot lifting push rod and the idling arc surface are idling. The thread trimming and presser foot lifting motors drive the presser foot lifting cam to lift the presser foot lifting cam surface, causing the presser foot lifting push rod to rise accordingly. When the presser foot lifting push rod reaches its highest point, the presser foot lifting push rod is lifted to its highest point, and the presser foot lifting execution end completes the presser foot lifting action.

[0017] During the presser foot lifting process, the pusher pushes the return rod, so that the pusher pushes the return rod to the original position, so that the entire thread trimming assembly is reset. The thread trimming assembly can effectively return to its original position even in the event of a stuck fault, and has a reset function.

[0018] When the presser foot is to be lowered, the thread trimmer and presser foot lifting motors move the presser foot lifting push rod back from the lifting surface of the presser foot lifting cam to the idling arc surface, thereby lowering the presser foot.

[0019] Compared with the prior art, the beneficial effects of the present application are as follows: By using the lifting tooth motor, the feeding motor and the feed dog of the present application, the lifting tooth motor is connected to and drives the lifting tooth shaft, and the feeding motor is connected to and drives the feeding shaft. Under the control of the control system of the sewing machine, the purpose of indirectly realizing the feeding action of the feed dog by the lifting tooth motor and the feeding motor is achieved. The sewing machine of the present application removes the traditional component of the swing seat, but can fully possess the functions of the swing seat. At the same time, it breaks the design concept of the traditional sewing machine and cancels the technology of the feeding connecting rod and the lifting tooth connecting rod connected and driven by the cam, making the manufacturing cost of the sewing machine reduced, the structure simple, and it is an efficient sewing machine without a lubrication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shows a schematic diagram of a feed dog drive mechanism of a sewing machine;

[0021] Figure 2 Shows a schematic diagram of a bobbin thread drive mechanism, an upper thread drive mechanism and a rotary hook drive assembly of a feed dog drive mechanism of a sewing machine;

[0022] Figure 3 Shows a schematic diagram of a feed drive assembly of a feed dog drive mechanism of a sewing machine;

[0023] Figure 4 Shows a schematic diagram of a thread cutting and presser foot lifting drive mechanism of a feed dog drive mechanism of a sewing machine;

[0024] Figure 5 Shows another schematic diagram of a thread cutting and presser foot lifting drive mechanism of a feed dog drive mechanism of a sewing machine.

[0025] Figure 6 Shows a schematic diagram of the position of the feeding motor in the second embodiment of the feed dog drive mechanism of a sewing machine.

[0026] Markings: lifting tooth motor 11, lifting tooth shaft 111, lifting tooth fork-shaped crank 112, feeding motor 21, feeding shaft 211, tooth carrier seat 212, tooth carrier 213, feed dog 214, movable shaft 2141, swing crank 215, connecting rod 216, feeding shaft crank 217, rotary hook motor 31, lower shaft 311, rotary hook 312, upper shaft motor 41, upper shaft 411, transmission member 412, needle bar 413, fan 414, hand wheel 415, connecting rod 416, needle plate 51, thread cutting and presser foot lifting motor 61, thread cutting crank 71, pushing member 7, thread cutting fork wheel 72, thread cutting rod 721, return rod 722, thread cutting execution end 73, presser foot cam 74, presser foot cam lifting surface 741, idle running arc surface 742, presser foot ejector rod 75, presser foot execution end 76, base plate 81. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will elaborate on the preferred embodiments of the present application in conjunction with the attached Figure 1-6 drawings to make the advantages and features of the present application more easily understood by those skilled in the art, thereby making the protection scope of the present application more clearly defined. These embodiments are only used to illustrate the present invention and are not intended to limit the present invention.

[0028] Embodiment 1

[0029] The present application provides a feed dog drive mechanism for a sewing machine, which includes a bobbin thread drive mechanism, an upper thread drive mechanism, a thread cutting and presser foot lifting drive mechanism, and a control system. Among them, the bobbin thread drive mechanism has a feed drive component and a rotary hook drive component. The feed drive component mainly consists of a lift tooth motor 11, a feed motor 21, a lift tooth shaft 111, a feed shaft 211, and a feed dog 214; the rotary hook drive component has a rotary hook motor 31, a lower shaft 311, and a rotary hook 312. The feed drive component is driven by the lift tooth motor 11 to drive the lift tooth shaft 111, and the feed motor 21 is connected to and drives the feed shaft 211 to indirectly achieve the feeding action of the feed dog 214; the rotary hook motor 31 is connected to and drives the lower shaft 311 to enable the rotary hook 312 connected to the lower shaft 311 to perform the thread taking and looping action. The feeding action of the feed dog 214 and the thread taking and looping action of the rotary hook 312 together achieve the bobbin thread drive mechanism of the sewing machine. The upper thread drive mechanism has an upper shaft motor 41, an upper shaft 411, a transmission member 412, and a needle bar 413. The upper shaft motor 41 is connected to and drives the upper shaft 411 to achieve the needle threading action of the upper thread drive mechanism. The feed drive component, the rotary hook drive component, and the upper thread drive mechanism realize the normal sewing work of the sewing machine under the control of the control system of the sewing machine. The present application breaks the design of the traditional drive mechanism that transmits power from the main shaft motor to the lower shaft through a vertical shaft. The four motors jointly drive to achieve the oil-free operation of the sewing machine. The upper and lower structures of the sewing machine are driven separately, without the need for lubricating oil for lubrication, and there is no need to match the complex taper gear sets between the upper shaft, the vertical shaft, and the lower shaft, which greatly reduces the manufacturing cost.

[0030] The bobbin thread drive mechanism is that the lift tooth motor 11 drives the lift tooth shaft 111 and the feed motor 21 drives the feed shaft 211 to simultaneously generate a feeding action on the feed dog 214. The above-mentioned lift tooth motor 11 and feed motor 21 are installed and fixed under the substrate 81, on both sides of the substrate 81, and the rotary hook motor 31 is installed and fixed between the lift tooth motor 11 and the feed motor 21. The lift tooth motor 11, the feed motor 21, and the rotary hook motor 31 are installed on one side of the rotary hook 312 of the sewing machine close to it.

[0031] The cloth feeding drive assembly also includes a bracket base 212, a bracket 213, cloth feed teeth 214, and a lifter fork-shaped crank 112. The lifter shaft 111 is directly connected to the output shaft of the lifter motor 11, or the lifter shaft 111 can also be integrated with the output shaft of the lifter motor 11. The front end of the lifter shaft 111 is equipped with a lifter fork-shaped crank 112, and the lifter fork-shaped crank 112 cooperates with the movable shaft 2141 of the bracket 213. The lifter fork-shaped crank 112 transmits a reciprocating swinging motion to the bracket 213 under the drive of the lifter motor 11 operating in a reciprocating back-and-forth swinging manner, causing the cloth feed teeth 214 to have a reciprocating swinging motion.

[0032] The cloth feed shaft 211 is directly connected to the output shaft of the cloth feed motor 21, or the cloth feed shaft 211 can also be integrated with the output shaft of the cloth feed motor 21. The front end of the cloth feed shaft 211 is equipped with a bracket base 212, the bracket base 212 is connected to a bracket 213, and the cloth feed teeth 214 are fixed on the bracket 213. The bracket base 212 and the bracket 213 transmit an up-and-down swinging motion to the bracket 213 under the drive of the cloth feed motor 21 operating in a reciprocating back-and-forth swinging manner, causing the cloth feed teeth 214 to have an up-and-down swinging motion.

[0033] The above-mentioned lifter motor 11 causes the cloth feed teeth 214 to have a reciprocating swinging motion, combined with the cloth feed motor 21 causing the cloth feed teeth 214 to have an up-and-down swinging motion, and the cloth feed teeth 214 thus form the cloth feeding function during sewing of the sewing machine.

[0034] The bobbin winder motor 31 drives the lower shaft 311 to rotate in a rotational manner, and the rotating lower shaft 311 drives the bobbin winder 312 to rotate to perform the action of taking up and hooking the thread. The cloth feeding action of the cloth feed teeth 214 and the action of taking up and hooking the thread of the bobbin winder 312 together achieve the bottom thread drive mechanism of the sewing machine.

[0035] The upper shaft motor 41 of the upper line driving mechanism drives the upper shaft 411 to rotate in a rotational manner. Through the transmission member 412 installed, the rotational movement of the upper shaft 411 is transformed into the up-and-down movement of the needle bar 413, realizing the cloth-piercing action of the thread-carrying needle bar 413 passing through the needle plate 51. There is no cam set on the upper shaft 411 like this, breaking the design concept of traditional sewing machines and canceling the technology of the feed link and the lifter link connected and driven by the cam, which reduces the cost in the manufacture of sewing machines and provides an efficient sewing machine without a lubrication system. The upper shaft motor 41 is installed on one side, in the middle, or at the rear of the upper shaft 411 close to the needle bar 413. A fan 414 is also configured at the rear of the upper shaft motor 41. The fan 414 is used to accelerate the air convection in the internal space of the sewing machine. A connecting rod 416 is also connected to the rear of the upper shaft motor 41. The end of the connecting rod 416 is fixedly connected to a handwheel 415 for adjusting the position of the needle bar 413. The upper shaft 411 and the connecting rod 416 both run synchronously with the drive of the upper shaft motor 41. The diameter of the connecting rod 416 is smaller than that of the upper shaft 411, and the diameter of the connecting rod 416 is relatively small. Here, there is no cam set on the upper shaft 411 where the upper shaft motor 41 is installed. Whether the upper shaft motor 41 is installed on one side, in the middle, or at the rear of the upper shaft 411 close to the needle bar 413 is within the protection scope claimed in this application.

[0036] The sewing machine of this application breaks the technical solution of traditional sewing machines, cancels the feed link, the lifter link, the cam on the main shaft, the vertical shaft, and the taper gear set between the vertical shaft and the lower shaft of traditional sewing machines. At the same time, the feed shaft 211 and the lifter shaft 111 (actually the lifter shaft and the feed shaft in existing sewing machines) can be made shorter to reduce the manufacturing cost. At the same time, the lifter amplitude of the feed dog 214 is also controlled by the control system, further improving the intelligent level of sewing. It should be pointed out that the traditional component of the swing seat is removed, but it can fully possess the functions of the swing seat. The lifter motor 11 and the feed motor 21 start driving and stop driving simultaneously under the control of the control system to achieve the coordinated feeding action of the feed dog driving mechanism, avoiding uncoordinated sewing actions where the feed dog 214 either only has a feeding action without a lifter action or only has a lifter action without a feeding action. Since the repeated back-and-forth rotation mode of the lifter motor 11 and the feed motor 21 is preset by the control system, the feeding action of the feed dog 214 always performs sewing work at a constant stitch length, that is, both feeding and lifting are in a constant state, overcoming the situation where there are deviations in the front and rear stitch lengths in existing sewing machine technologies, effectively improving the sewing quality and the stability of sewing work.

[0037] The thread trimming and presser foot lifting drive mechanism of the feed dog drive mechanism of a sewing machine of the present application comprises a thread trimming assembly and a presser foot lifting assembly, wherein the thread trimming assembly comprises a thread trimming and presser foot lifting motor 61, a thread trimming crank 71, a thread trimming fork wheel 72 and a thread trimming execution end 73. The thread trimming crank 71 comprises a pusher 711, which is arranged at an eccentric position of the thread trimming crank 71. The pusher 711 pushes the thread trimming fork wheel 72 to perform the thread trimming action, and the thread trimming fork wheel 72 comprises a return rod 722 and a thread trimming rod 721, and the pusher 711 is located between the return rod 722 and the thread trimming rod 721. When the thread trimming and presser foot lifting motor 61 drives the thread trimming crank 71, the pusher 711 pushes the thread trimming rod 721 so that the thread trimming execution end 73 performs the thread trimming action.

[0038] The presser foot lifter assembly includes a thread trimmer and presser foot lifter motor 61, a presser foot lifter cam 74, a presser foot lifter rod 75, and a presser foot lifter actuator 76. The presser foot lifter cam 74 includes a presser foot lifter cam lifting surface 741 and an idle arc surface 742. The presser foot lifter cam 74 is fixed to the output shaft of the thread trimmer and presser foot lifter motor 61. The presser foot lifter cam lifting surface 741 is used to adjust the presser foot lifter rod 75 from a lower or higher position to a higher or lower position. The idle arc surface 742 is used for idle rotation between the presser foot lifter rod 75 and the presser foot lifter cam 74. The idle arc surface 742 is concentric with the output shaft of the thread trimmer and presser foot lifter motor 61. The presser foot lifter cam lifting surface 741 is located on the cam portion of the presser foot lifter cam 74.

[0039] After the thread trimming action is completed, the presser foot lifting cam 74 starts to perform the presser foot lifting action. The angle of rotation of the thread trimming and presser foot lifting motor 61 during the thread trimming action does not cause the presser foot lifting cam 74 to actually lift the presser foot lifting rod 75. The presser foot lifting rod 75 and the idling circular arc surface 742 are in idling rotation. The thread trimming and presser foot lifting motor 61 drives the presser foot lifting cam lifting surface 741 of the presser foot lifting cam 74 to lift the presser foot lifting rod 75 accordingly. When the presser foot lifting rod 75 reaches its highest point, the presser foot lifting rod 75 is lifted to its highest point, and the presser foot lifting execution end 76 completes the presser foot lifting action.

[0040] The thread trimming and presser foot lifting motor 61 drives the presser foot lifting cam 74 when trimming the thread. Under the drive of the thread trimming and presser foot lifting motor 61, the presser foot lifting cam 74 gradually transitions from the idling arc surface 742 to the presser foot lifting cam lifting surface 741 until it reaches the highest point of the presser foot lifting, thereby realizing the presser foot lifting action. At this time, the thread trimming and presser foot lifting motor 61 is locked so that the presser foot lifting state is maintained for a period of time, forming a sewing action of immediately lifting the presser foot after the thread is cut.

[0041] In addition, during the process of lifting the presser foot, the pusher 711 pushes the return rod 722, so that the pusher 711 pushes the return rod 722 to its original position, thereby resetting the entire thread trimming assembly. This can effectively return the thread trimming assembly to its original position even in a stuck fault state, and has a reset function.

[0042] When the presser foot is to be lowered, the thread trimming and presser foot lifting motor 61 moves the presser foot lifting push rod 75 back from the presser foot lifting cam lifting surface 741 to the idle arc surface 742 to achieve the presser foot lowering action.

[0043] Here, there is another scenario where the presser foot is lifted without trimming the thread, which is usually when the stitches need to be made at a large bend. The thread trimming and presser foot lifting motor 61 drives the presser foot lifting cam lifting surface 741 to push the presser foot lifting push rod 75 to the highest point of the presser foot. When the presser foot is lowered, the thread trimming and presser foot lifting motor 61 drives the presser foot lifting cam lifting surface 741 to return from the reverse direction to complete the presser foot lowering action.

[0044] Example 2

[0045] exist Figure 6 In the embodiment 1, the present invention is substantially the same as the embodiment 2, except that the cloth feed motor 21 is mounted on the side of the sewing machine body, the cloth feed shaft 211 extends to a position below the cloth feed motor 21, and a swing crank 215, a connecting rod 216, and a cloth feed shaft crank 217 are provided between the cloth feed motor 21 and the cloth feed shaft 211. The swing crank 215 is fixed to the output shaft of the cloth feed motor 21, the swing crank 215 is hinged to the connecting rod 216, and the connecting rod 216 is hinged to the cloth feed shaft crank 217, and the cloth feed shaft crank 217 is fixed to the rear end of the cloth feed shaft 211.

[0046] The swing crank 215 realizes the upward and downward feeding action of the feed dog 214 by driving the feed motor 21. Here, the feed motor output shaft of the tooth lifting motor 11 can also directly fix the feed shaft crank 217, and transmit the swing source to the feed shaft crank 217, and then the feed shaft crank 217 transmits it to the feed shaft 211, the tooth rack 213 and finally reaches the feed dog 214. The technical effect is the same as that of the swing crank 215, and both can make the feed dog 214 produce the upward and downward feeding action.

[0047] A tooth frame seat 212 is installed at the front end of the cloth feed shaft 211, and the tooth frame seat 212 is connected to the tooth frame 213. A feed dog 214 is fixed on the tooth frame 213. The tooth frame seat 212 and the tooth frame 213 are driven by the cloth feed motor 21 in a repeated back and forth swinging operation mode to transmit the up and down swinging motion to the tooth frame 213, so that the cloth feed dog 214 has an up and down swinging motion.

[0048] The above is only one of the preferred implementation methods of this application, and does not limit the scope of patent implementation of this application. Any equivalent structure or equivalent process transformation based on the shape, structure, and principle of the description and drawings of this application, or direct or indirect application in other related technical fields, is included in the scope of patent protection of this application.

Claims

1. A feed dog drive mechanism for a sewing machine, having a lifter shaft and a feed shaft, characterized in that, It also has a lifting tooth motor, a feeding motor and a feed dog. The lifting tooth motor is connected to and drives a lifting tooth shaft. The feeding motor is connected to and drives a feeding shaft. The lifting tooth shaft is directly connected to the output shaft of the lifting tooth motor, or the lifting tooth shaft and the output shaft of the lifting tooth motor are integrated. A lifting tooth fork-shaped crank is installed at the front end of the lifting tooth shaft. The lifting tooth fork-shaped crank cooperates with a movable shaft of the feed dog frame. The lifting tooth fork-shaped crank transmits a back-and-forth swinging motion to the frame under the drive of the lifting tooth motor in a repeatedly back-and-forth swinging operation mode, so that the feed dog has a back-and-forth swinging motion. The feeding shaft is directly connected to the output shaft of the feeding motor, or the feeding shaft and the output shaft of the feeding motor are integrated. A frame seat is installed at the front end of the feeding shaft. The frame seat is connected to a frame, and a feed dog is fixed on the frame. The frame seat and the frame transmit an up-and-down swinging motion to the frame under the drive of the feeding motor in a repeatedly back-and-forth swinging operation mode, so that the feed dog has an up-and-down swinging motion. The lifting tooth motor and the feeding motor are installed and fixed under the base plate. The lifting tooth motor and the feeding motor are located on both sides of the base plate. The lifting tooth motor and the feeding motor are installed on the side close to the bobbin case of the sewing machine.

2. The feed dog drive mechanism of a sewing machine according to claim 1, characterized in that, It also has a bobbin case motor. The bobbin case motor is connected to and drives the lower shaft to realize the thread-taking and thread-hooking actions of the bobbin case connected to the lower shaft. The bobbin case motor drives the lower shaft to rotate in a rotating manner.

3. The feed dog drive mechanism of a sewing machine according to claim 2, characterized in that, The bobbin case motor is installed and fixed between the lifting tooth motor and the feeding motor. The lifting tooth motor is installed on the side close to the bobbin case of the sewing machine.

4. The feed dog drive mechanism of a sewing machine according to claim 1, characterized in that, It also has an upper shaft motor. The upper shaft motor is installed on the side close to the needle bar, or in the middle or at the rear of the upper shaft. A fan is also configured at the rear of the upper shaft motor. A connecting rod is also connected to the rear of the upper shaft motor. The end of the connecting rod is fixedly connected to a handwheel for adjusting the position of the needle bar. The upper shaft motor drives the upper shaft to rotate in a rotating manner. Through a transmission member installed on the upper shaft to convert the rotational movement into the up-and-down movement of the needle bar, the cloth-piercing action of the thread-carrying needle bar passing through the needle plate is realized.

5. The feed dog drive mechanism of a sewing machine according to claim 4, characterized in that, The diameter of the connecting rod is smaller than that of the upper shaft.

6. The feed dog drive mechanism of a sewing machine according to claim 1, characterized in that, The feeding motor is installed on the side body of the sewing machine. The feeding shaft extends all the way to the lower position of the feeding motor. A swinging crank, a connecting rod and a feeding shaft crank are arranged between the feeding motor and the feeding shaft. A swinging crank is fixed on the output shaft of the feeding motor. The swinging crank is hinged to the connecting rod. The connecting rod is hinged to the feeding shaft crank. The feeding shaft crank is fixed at the rear end of the feeding shaft. The feeding motor drives the up-and-down swinging motion to be transmitted to the frame in a repeatedly back-and-forth swinging operation mode, so that the feed dog has an up-and-down swinging motion.

7. The feed dog drive mechanism of a sewing machine according to claim 1, characterized in that, It also has a presser foot lifting assembly and a thread cutting assembly. The presser foot lifting assembly has a thread cutting and presser foot lifting motor, a presser foot lifting cam, a presser foot lifting rod and a presser foot execution end. The presser foot lifting cam has a presser foot lifting cam lifting surface and an idle running arc surface. The presser foot lifting cam is fixed on the output shaft of the thread cutting and presser foot lifting motor. The presser foot lifting cam lifting surface is used to adjust the presser foot lifting rod from a lower or higher position to a higher or lower position. The idle running arc surface is used for the idle running between the presser foot lifting rod and the presser foot lifting cam. The idle running arc surface is concentric with the output shaft of the thread cutting and presser foot lifting motor. The presser foot lifting cam lifting surface is located at the cam part of the presser foot lifting cam. The thread trimming assembly comprises a thread trimming and presser foot lifting motor, a thread trimming crank, a thread trimming fork wheel and a thread trimming execution end. The thread trimming crank has a pushing member, which is arranged at an eccentric position of the thread trimming crank. The pushing member pushes the thread trimming fork wheel to perform the thread trimming action. The thread trimming fork wheel has a return rod and a thread trimming rod. The pushing member is located between the return rod and the thread trimming rod. When the thread trimming and presser foot lifting motor drives the thread trimming crank, the pushing member pushes the thread trimming rod so that the thread trimming execution end performs the thread trimming action. After the thread trimming action is completed, the presser foot lifting cam starts to perform the presser foot lifting action. The rotation angle of the thread trimming and presser foot lifting motors during the thread trimming action will not cause the presser foot lifting cam to produce an actual presser foot lifting action on the presser foot lifting push rod. The presser foot lifting push rod and the idling arc surface are idling. The thread trimming and presser foot lifting motors drive the presser foot lifting cam to lift the presser foot lifting cam surface, causing the presser foot lifting push rod to rise accordingly. When the presser foot lifting push rod reaches its highest point, the presser foot lifting push rod is lifted to its highest point, and the presser foot lifting execution end completes the presser foot lifting action. During the presser foot lifting process, the pusher pushes the return rod, causing the pusher to push the return rod to its original position, thereby resetting the entire thread trimming assembly. This effectively returns the thread trimming assembly to its original position even in a stuck fault state, thus providing a reset function. When the presser foot is to be lowered, the thread trimmer and presser foot lifting motors move the presser foot lifting push rod back from the lifting surface of the presser foot lifting cam to the idling arc surface, thereby lowering the presser foot.

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