A sewing machine with a zero position

Abstract

The present application provides a sewing machine with a zero position, specifically related to the technical field of sewing machine manufacturing, including a driving motor, a swing seat, a cam, and a rotating combination wheel. The driving motor is fixedly installed with a cam. The stitch length adjustment working surface of the cam is used to change the acting position with the stitch distance adjustment acting surface of the rotating combination wheel. The zero-position positioning rod of the cam rotates and acts on the positioning chute of the rotating combination wheel. The rotating combination wheel indirectly acts on the swing seat and makes the swing seat in the zero position state. A sewing machine with a zero position according to the present application realizes that a driving motor flexibly controls the stitch length adjustment, thread cutting, and presser foot lifting actions, and under the control of the electric control system of this sewing machine, the feed dog is in the zero position. The actual product has strong creativity, the sewing action is completed in one go, and has high popularization and application value.

Description

Technical Field

[0001] The present application provides a sewing machine with a zero position, specifically relating to the technical field of sewing machine manufacturing. Background Art

[0002] The sewing machine is equipped with a stitch length adjustment mechanism, which is used to adjust the stitch length of the sewing machine. The stitch length adjustment mechanism has a function of switching between the forward sewing mode and the reverse sewing mode. The central point between the forward sewing mode and the reverse sewing mode is the zero position, which is the zero position state of the swing seat of the sewing machine. When adjusting the stitch length, it is usually carried out when the sewing machine is in a stopped state. The old-fashioned sewing machine is adjusted by rotating the stitch length adjustment lever in the stitch length adjustment mechanism. When the stitch length adjustment stud is rotated, it will move forward or to the right at the same time. The zero position of the swing seat in the feeding mechanism is driven by the stitch length adjustment mechanism to rotate around its fulcrum, so as to adjust the actual distance between the positive stitch length and the negative stitch length of the swing seat, and then change the swing angle of the swing seat to achieve the corresponding stitch length adjustment.

[0003] When the stitch length of the sewing machine is zero, the sewing machine needle staying below the needle plate is called the lower needle position, and the sewing machine needle staying above the needle plate is called the upper needle position. At the end of sewing of a pedal-operated sewing machine, the staying position of the sewing machine is determined by the end of the sewing stitch. The staying position of the sewing machine needle has a certain impact on the subsequent sewing work. If it stays at the lower needle position, turning the handwheel to lift the sewing machine needle can solve the problem; if it stays at the upper needle position, reverse the handwheel to lower the feed dog below the needle plate. When the feed dog stays in a state where it is higher than the needle plate, when taking out the sewn fabric under the presser foot and when pushing the fabric under the presser foot in the next sewing operation, it is possible that the feed dog will catch the fabric, resulting in the fabric being damaged.

[0004] In the above solution of the pushing device for pushing the feed dog, since an additional driving device needs to be added, this naturally increases the manufacturing cost of the sewing machine. Installing this pushing device at the bottom of the sewing machine base is relatively inconvenient during the production and assembly process, whether it is installed on the feed shaft or other related components. The pushing device occupies a large space, making the base messy. In addition, the disadvantage of this pushing device is that regardless of whether the feed dog is below or above the needle plate, the pushing device has to implement a preset pushing plan, its intelligent level is relatively low, and there is also the disadvantage of wasting energy. Summary of the Invention

[0005] Aiming at the technical problem of the existing feed dog technology of sewing machines having a problem with the staying position, the present application provides a sewing machine with a zero position, including a driving motor and a swing seat. It is characterized in that it further includes a cam and a rotating combination wheel. The driving motor is fixedly installed with a cam. The stitch pitch adjustment working surface of the cam is used to change the acting position with the stitch adjustment acting surface of the rotating combination wheel. The zero point positioning rod of the cam rotates and acts on the positioning chute of the rotating combination wheel. The rotating combination wheel indirectly acts on the swing seat and makes the swing seat in the zero position state.

[0006] Preferably, the driving motor is a double-headed power output driving motor. The driving motor is provided with an output shaft one and an output shaft two. The output shaft one is installed with a cam to execute the stitch pitch adjustment action of the stitch pitch adjustment mechanism and the presser foot lifting action of the presser foot mechanism; the output shaft two is installed with a thread cutting crank to execute the thread cutting action of the thread cutting mechanism.

[0007] Preferably, it further includes a stitch pitch adjustment mechanism. The stitch pitch adjustment mechanism has a transmission shaft sleeve. The rotating combination wheel is fixedly connected to the transmission shaft sleeve. The transmission shaft sleeve is sleeved on the feed shaft. The transmission shaft sleeve and the feed shaft are in clearance fit. The other end of the transmission shaft sleeve is connected with a connecting block. The swing seat is hinged with a transmission connecting rod. The transmission connecting rod is fixed on the connecting block. The zero point positioning rod has a positioning surface adjacent to it.

[0008] Preferably, the rotating combination wheel and the transmission shaft sleeve are manufactured integrally, and the two are sleeved on the feed shaft as a whole; or, the transmission shaft sleeve and the connecting block are manufactured integrally.

[0009] Preferably, the positioning chute of the rotating combination wheel has a bell mouth one and a bell mouth two at both ends. The zero point positioning rod slides freely in the positioning chute part.

[0010] Preferably, the contact action point of the zero point positioning rod on the bell mouth one is the working determination point for determining the position of the feed dog, and it is determined that the position of the feed dog is below the needle plate; the contact action point of the zero point positioning rod on the bell mouth two is the working determination point for determining the position of the feed dog, and it is determined that the position of the feed dog is below the needle plate. The zero point positioning rod retreats from the bell mouth two to the original position.

[0011] Preferably, the cam has a shaft hole for fixing the cam on the output shaft one of the driving motor. The shaft hole is located between the stitch pitch adjustment working surface and the zero point positioning rod, and the shaft hole, the stitch pitch adjustment working surface and the zero point positioning rod are located on the connection line of the center lines of the three. The stitch pitch adjustment working surface and the zero point positioning rod rotate around the shaft hole.

[0012] Preferably, the positioning groove and the stitch length adjustment action surface rotate with the cloth feed shaft as the rotation axis, the center line of the positioning groove and the stitch length adjustment action surface is colinear with the center line of the cloth feed shaft, and the combined wheel is rotated with the cloth feed shaft as the rotation axis under the action of the cam. After the zero-point positioning rod enters the positioning groove, the active zero-point positioning rod always forms a fixed positioning for the transmission sleeve for the static positioning groove, and the zero-point positioning rod operates inside the positioning groove, and the feed dog is in the lower needle position.

[0013] Preferably, a thread trimming mechanism is also included, which specifically includes a thread trimming fork wheel, a thread trimming crank and a thread trimming end actuator. The thread trimming crank has a thread trimming movable rod, and the thread trimming movable rod is located between the thread trimming action surface and the idling surface of the thread trimming fork wheel.

[0014] Preferably, it also includes a presser foot lifting mechanism, the cam has a presser foot working surface and a circular surface, the presser foot lifting mechanism includes a presser foot push rod and a presser foot lifting terminal actuator assembly, the presser foot working surface generates a lifting force on the presser foot push rod as the cam curvature changes, and then the presser foot lifting action is performed by the presser foot lifting terminal actuator assembly.

[0015] Preferably, there is also a thread loosening mechanism. In addition to the cam installed on the output shaft 1 of the driving motor, the output shaft 1 also has one of the following schemes installed together: the output shaft 1 is also equipped with a thread loosening mechanism and a presser foot lifting mechanism; the output shaft 1 is also equipped with a thread loosening mechanism.

[0016] The beneficial effect of the present application is that the cam is driven by the driving motor, and the cam drives the rotating combination wheel, so that the stitch length adjustment working surface and the stitch length adjustment action surface thereon perform the stitch length adjustment action; so that the stitch length adjustment working surface and the stitch length adjustment action surface thereon perform the stitch length adjustment action. After the driving motor drives the cam, the movable zero-point positioning rod always forms a fixed positioning position for the static positioning slide groove to the transmission shaft sleeve, thereby realizing the positioning of the lower needle position of the feed dog, and the driving motor takes advantage of the zero-point positioning rod to idle in the positioning slide groove to perform other sewing actions. The present application has a sewing machine with a zero-point position, which not only realizes a flexible control of stitch length adjustment, thread trimming and presser foot lifting actions by a driving motor, but also realizes the feed dog being at the zero-point position under the control of the electric control system of the sewing machine. The actual product has strong creativity, and the sewing action is completed in one go, which has a high value of promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a sewing machine with a zero point position of the present application;

[0018] Figure 2 It is a schematic diagram of the feed dog position and feed shaft of a sewing machine with a zero point position of the present application;

[0019] Figure 3Exploded view of the stitch pitch adjusting mechanism of a sewing machine with a zero position according to the present application;

[0020] Figure 4 Enlarged view of the feed dog of a sewing machine with a zero position according to the present application;

[0021] Figure 5 Another view of the stitch pitch adjusting mechanism of a sewing machine with a zero position according to the present application;

[0022] Figure 6 Structural diagram of the rotating combination wheel of a sewing machine with a zero position according to the present application;

[0023] Figure 7 Structural diagram of the zero position positioning rod of a sewing machine with a zero position according to the present application;

[0024] Figure 8 Structural diagram of the thread cutting mechanism of a sewing machine with a zero position according to the present application.

[0025] Reference numerals: Stitch pitch adjusting mechanism 10, rotating combination wheel 11, stitch pitch adjusting working surface 111, positioning chute 112, first bell mouth 113, second bell mouth 114, positioning surface 115, feed shaft 12, feed crank 121, transmission shaft sleeve 13, swing seat 14, short swing plate 141, long swing plate 142, transmission connecting rod 15, connecting block 16, feed connecting rod 17, presser foot lifting mechanism 20, presser foot lifting rod 21, presser foot lifting end execution assembly 22, drive motor 50, first output shaft 51, second output shaft 52, cam 61, circular surface 62, stitch pitch adjusting working face 63, zero position positioning rod 64, shaft hole 65, presser foot working face 66, feed dog 7, feed dog support 71, needle plate 8, thread cutting mechanism 90, thread cutting fork wheel 91, thread cutting working surface 911, idle running surface 912, thread cutting crank 92, thread cutting moving rod 921, thread cutting end execution assembly 93. Detailed implementation manners

[0026] The following combines Figure 1-8 to elaborate in detail on the preferred embodiments of the present application, so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application. These implementation manners are only used to illustrate the present invention and are not intended to limit the present invention.

[0027] This application relates to a sewing machine with a zero position, which includes a stitch length adjustment mechanism 10, a presser foot lifting mechanism 20, a thread cutting mechanism 90, a driving motor 50, and an electronic control system. The driving motor 50 drives the stitch length adjustment mechanism 10, the presser foot lifting mechanism 20, and the thread cutting mechanism 90 respectively in different time periods to perform their respective sewing operations. The driving motor 50 is a double-headed power output driving motor, and the driving motor 50 has an output shaft one 51 and an output shaft two 52. A cam 61 is installed on the output shaft one 51 to perform the stitch length adjustment operation of the stitch length adjustment mechanism 10 and the presser foot lifting operation of the presser foot lifting mechanism 20; a thread cutting crank 92 is installed on the output shaft two 52 to perform the thread cutting operation of the thread cutting mechanism 90.

[0028] As another solution, this application also has a thread loosening mechanism. The cam 61 installed on the output shaft one 51 to perform the sewing operation has one of the following: performing the thread loosening mechanism and the presser foot lifting mechanism 20; performing the thread loosening mechanism alone; performing the presser foot lifting mechanism 20 alone.

[0029] The cam 61 has a shaft hole 65 for fixing the cam 61 on the output shaft one 51 of the driving motor 50. The shaft hole 65 is located between the stitch length adjustment working surface 63 and the zero point positioning rod 64, and the shaft hole 65, the stitch length adjustment working surface 63, and the zero point positioning rod 64 are located on the connecting line of their center lines. The cam 61 rotates around the output shaft one 51 of the driving motor 50, that is, the stitch length adjustment working surface 63 and the zero point positioning rod 64 on the cam 61 also rotate around the shaft hole 65. The zero point positioning rod 64 has an adjacent positioning surface 115.

[0030] Under the action of the cam 61, the rotating combination wheel 11 rotates around the feed shaft 12, and the positioning chute 112 and the stitch length adjustment action surface 111 naturally also rotate around the feed shaft 12. The center connecting line of the positioning chute 112 and the stitch length adjustment action surface 111 is collinear with the center line of the feed shaft 12.

[0031] This application is a sewing machine with a determined zero position of the feed dog 7. The first technical solution to be achieved is to adjust the stitch length in the sewing machine's stopped state. The electronic control device of the sewing machine drives the output shaft one 51 through the driving motor 50 to drive the cam 61 to adjust the acting position with the rotating combination wheel 11, indirectly adjusting the swing amplitude of the swing seat 14, thereby achieving stitch length adjustment. The sewing machine after the stitch length adjustment performs sewing with a fixed stitch length; the second is that the electronic control device of the sewing machine drives the output shaft one 51 through the driving motor 50 to drive the cam 61 to push the rotating combination wheel 11, indirectly making the swing seat 14 in the zero position state. The swing seat 14 being in the zero position state is usually reflected in the short swing plate 141 and the long swing plate 142 being in a flush position, and indirectly making the feed dog 7 in the zero position without front and back feeding actions.

[0032] The above-mentioned stitch length adjusting mechanism 10 includes a rotating combination wheel 11, a feed shaft 12, a transmission shaft sleeve 13, a swing seat 14, a transmission connecting rod 15 and a connecting block 16. The rotating combination wheel 11 is fixedly connected to the transmission shaft sleeve 13. The transmission shaft sleeve 13 is sleeved on the feed shaft 12. There is a positioning device to assist the transmission shaft sleeve 13 to make the zero position stable and reliable, and there is a clearance fit relationship between the transmission shaft sleeve 13 and the feed shaft 12. The rotating combination wheel 11 and the transmission shaft sleeve 13 rotate at a certain angle with the feed shaft 12 as the rotation axis. The other end of the transmission shaft sleeve 13 is connected with a connecting block 16. The swing seat 14 is hinged to the transmission connecting rod 15, and the transmission connecting rod 15 is fixed on the connecting block 16. Several fixing holes are provided on the connecting block 16, and the connecting block 16 and the transmission connecting rod 15 are fixedly connected in a variable manner. Here, different fixing holes are selected between the connecting block 16 and the transmission connecting rod 15 according to the requirements of different stitch lengths for fixing, and the purpose of adjusting the stitch length can also be achieved. As another implementation, the rotating combination wheel 11 and the transmission shaft sleeve 13 are made into an integral body, and the two are sleeved on the feed shaft 12 as a whole; as another implementation, the transmission shaft sleeve 13 and the connecting block 16 are made into an integral body to make the structure more stable.

[0033] The implementation of the stitch length adjustment action of the stitch length adjusting mechanism 10 is driven by the operation of the driving motor 50. The stitch length adjusting working surface 63 of the cam 61 matches the stitch length adjusting action surface 111 of the rotating combination wheel 11. The cam 61 changes the acting position with the stitch length adjusting action surface 111 during the operation of the driving motor 50. The rotation of the rotating combination wheel 11 causes the stitch length adjusting action surface 111 and the entire rotating combination wheel 11 and the transmission shaft sleeve 13 to rotate a certain angle together. The rotating transmission shaft sleeve 13 drives the connected connecting block 16, and finally the transmission connecting rod 15 changes the swing amplitude of the swing seat 14, realizing the indirect adjustment of the swing seat 14 by the cam 61 and achieving the stitch length adjustment of the sewing machine.

[0034] When the sewing machine needs to cut the thread at the end of sewing, the above-mentioned cam 61 and the rotating combination wheel 11 have the function of determining the zero position of the feed dog 7. There is a working matching relationship between the zero-position positioning rod 64 of the above-mentioned cam 61 and the positioning chute 112 of the rotating combination wheel 11. The zero-position positioning rod 64 indirectly affects the positioning feed dog 7 under the drive of the drive motor 50, causing it to lose the power of feeding forward and backward. When the drive motor 50 drives the cam 61 to drive the zero-position positioning rod 64 to rotate, the zero-position positioning rod 64 first contacts the first bell mouth 113 when rotating, and continues to enter the positioning chute 112 from the first bell mouth 113. While the zero-position positioning rod 64 pushes the first bell mouth 113, it also pushes the entire rotating combination wheel 11 and the transmission shaft sleeve 13 to rotate. The connecting block 16 and the transmission connecting rod 15 linked with the transmission shaft sleeve 13 push the swing seat 14. The positions of the short swing plate 141 and the long swing plate 142 of the pushed swing seat 14 are in a flush state. When the cam 61 enters the zero-position positioning rod 64 in the positioning chute 112, the moving zero-position positioning rod 64 always forms a fixed positioning for the transmission shaft sleeve 13 with the stationary positioning chute 112. When the above-mentioned zero-position positioning rod 64 operates inside the positioning chute 112, the feed dog 7 is in the zero position of the feed dog 7.

[0035] Although, at this time, the swing seat 14 will still receive the swing source of the feed connecting rod 17 under the operation of the main shaft motor, but the swing seat 14 pushed by the transmission connecting rod 15 reaches the feed shaft 12 through the feed crank 121 and is in a stationary state, so that the feed dog bracket 71 fixed on the feed shaft 12 stops twisting, and the feed dog 7 on the feed dog bracket 71 loses the power of feeding forward and backward, thus determining the zero position of the feed dog 7. The contact action point of the above-mentioned zero-position positioning rod 64 on the first bell mouth 113 is the working determination point for determining the zero position of the feed dog 7. Determining the zero position of the feed dog 7 under the needle plate 8, the drive motor 50 can immediately execute the thread cutting and presser foot lifting actions, achieving the technical effect of thread cutting at the zero position in this application.

[0036] Both ends of the above-mentioned positioning chute 112 have an inlet of the first bell mouth 113 and the second bell mouth 114. The zero-position positioning rod 64 can slide freely inside the positioning chute 112, that is, it can slide freely between the first bell mouth 113 and the second bell mouth 114. The zero-position positioning rod 64 operates between the first bell mouth 113 and the second bell mouth 114 of the positioning chute 112. Whether the zero-position positioning rod 64 enters the positioning chute 112 from the first bell mouth 113 or the second bell mouth 144, the positioning effect is the same.

[0037] After the sewing machine locates the zero position, the driving motor 50 performs the presser foot lifting and lowering action on the presser foot mechanism 20 and the thread cutting action on the thread cutting mechanism 90. Here, the sewing machine can also perform the thread loosening action of the thread loosening mechanism. When the zero position positioning rod 64 is in the positioning chute 112, the sewing action or steps that the driving motor 50 will perform next are not limited and can be actually implemented according to the sewing process or the structure of the sewing machine.

[0038] The thread cutting action specifically includes: a thread cutting mechanism 90 is installed on the output shaft two 52 of the driving motor 50. The thread cutting mechanism 90 specifically includes a thread cutting fork wheel 91, a thread cutting crank 92, and a thread cutting end execution assembly 93. The thread cutting crank 92 has a thread cutting moving rod 921, and the above-mentioned thread cutting moving rod 921 is located between the thread cutting working surface 911 and the idle running surface 912 of the thread cutting fork wheel 91. When the zero position positioning rod 64 starts to enter the positioning chute 112, the above-mentioned thread cutting action immediately starts. The driving motor 50 drives the thread cutting moving rod 921 of the thread cutting crank 92 to push the thread cutting working surface 911 of the thread cutting fork wheel 91, thereby rotating the thread cutting fork wheel 91 and realizing the thread cutting end execution assembly 93 to perform thread cutting.

[0039] The presser foot mechanism 20 includes: a presser foot lifting rod 21 and a presser foot lifting and lowering end execution assembly 22. The above-mentioned thread cutting action is almost simultaneous with the presser foot lifting and lowering action. The presser foot lifting and lowering action specifically includes: the cam 61 has a presser foot working surface 66 and a circular surface 62. After sewing stops, when the zero position positioning rod 64 starts to enter the positioning chute 112, since the zero position positioning rod 64, the presser foot working surface 66, and the circular surface 62 rotate simultaneously, the circular surface 62 does not generate a thrust on the presser foot lifting rod 21, and the contact part between the two is only surface friction. The presser foot working surface 66 of the cam 61 generates a lifting force on the presser foot lifting rod 21 as the radian of the cam 61 changes, and then the presser foot lifting and lowering end execution assembly 22 performs the presser foot lifting and lowering action, thereby realizing the presser foot lifting and lowering action of the zero position positioning rod 64 inside the positioning chute 112.

[0040] During the actual sewing process, it is necessary to perform the presser foot lifting and lowering to realize sewing with a changed stitch direction, such as a right-angle bend of the stitch. After the sewing machine stops, the contact point of the zero position positioning rod 64 with the second bell mouth 114 is the working determination point for determining the zero position of the feed dog 7 and enters the positioning chute 112. At this time, the thread cutting moving rod 921 does not generate a thrust on the thread cutting working surface 911 and only idles in contact with the idle running surface 912. At the same time, the presser foot working surface 66 of the cam 61 gradually generates a lifting force on the presser foot lifting rod 21, causing the presser foot to be successfully lifted, facilitating the sewing with a changed stitch direction. After the stitch direction is changed and the presser foot is lowered, the zero position positioning rod 64 retracts from the second bell mouth 114 to the original zero position.

[0041] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A sewing machine having a zero position, comprising a drive motor (50) and a swing seat (14), characterized in that, It further includes a cam (61) and a rotating combination wheel (11). A cam (61) is fixed on an output shaft one (51) of the driving motor (50). The cam (61) has a zero-point positioning rod (64). The rotating combination wheel (11) has a positioning chute (112), a first flared opening (113) and a second flared opening (114) at two ends of the positioning chute (112). The zero-point positioning rod (64) rotates and acts on the positioning chute (112) and can freely slide inside the positioning chute (112). The rotating combination wheel (11) is fixedly connected to a transmission shaft sleeve (13). The other end of the transmission shaft sleeve (13) is connected to a connecting block (16). A transmission connecting rod (15) is fixed on the connecting block (16). A swing seat (14) is hinged to the transmission connecting rod (15). The zero-point positioning rod (64) operates between the first flared opening (113) and the second flared opening (114). After the driving motor (50) drives the cam (61) to drive the zero-point positioning rod (64) to rotate, the zero-point positioning rod (64) first contacts the first flared opening (113) when rotating and continues to enter the positioning chute (112) from the first flared opening (113). While the zero-point positioning rod (64) pushes the first flared opening (113), it also pushes the entire rotating combination wheel (11) and the transmission shaft sleeve (13) to rotate. The connecting block (16) and the transmission connecting rod (15) linked with the transmission shaft sleeve (13) push the swing seat (14). When the zero-point positioning rod (64) of the cam (61) enters the positioning chute (112), the movable zero-point positioning rod (64) always forms a fixed positioning for the transmission shaft sleeve (13). When the zero-point positioning rod (64) operates inside the positioning chute (112), the feed dog (7) is at the zero position where the feed dog (7) has no forward and backward feeding action. The rotating combination wheel (11) and the transmission shaft sleeve (13) are made into an integral body and are sleeved on the feed shaft (12) as a whole. Or, the transmission shaft sleeve (13) and the connecting block (16) are made into an integral body. The transmission shaft sleeve (13) is sleeved on the feed shaft (12), and the transmission shaft sleeve (13) has a clearance fit with the feed shaft (12).

2. The sewing machine with a zero position according to claim 1, characterized in that, The rotating combination wheel (11) further has a stitch pitch adjusting working surface (111). The cam (61) further has a stitch pitch adjusting working surface (63). The stitch pitch adjusting working surface (63) is used to change the acting position with the stitch pitch adjusting working surface (111).

3. The sewing machine with a zero position according to claim 2, characterized in that, The cam (61) has a shaft hole (65). The shaft hole (65) is used for fixing the cam (61) on the output shaft one (51). The stitch pitch adjusting working surface (63) and the zero-point positioning rod (64) rotate around the shaft hole (65).

4. A sewing machine having a zero position according to claim 2, characterized in that, The stitch pitch adjusting working surface (111) rotates with the feed shaft (12) as the rotation axis.

5. A sewing machine with a zero position according to claim 1, characterized in that It further includes a thread cutting mechanism (90), the thread cutting mechanism (90) includes a thread cutting fork wheel (91) and a thread cutting crank (92), the thread cutting crank (92) has a thread cutting moving rod (921), the thread cutting fork wheel (91) has a thread cutting working surface (911) and an idle running surface (912), and the thread cutting moving rod (921) is located between the thread cutting working surface (911) and the idle running surface (912).

6. A sewing machine having a zero position according to claim 1, characterized in that, It further includes a presser foot lifting mechanism (20), the cam (61) has a presser foot working surface (66), the presser foot lifting mechanism (20) includes a presser foot ejector rod (21) and a presser foot lifting end execution assembly (22), and the presser foot working surface (66) generates a lifting force on the presser foot ejector rod (21) as the radian of the cam (61) changes, and then the presser foot lifting end execution assembly (22) executes the presser foot lifting action.

Images