Sewing Machine
Through the spiral groove and protruding structure, the rotation shaft is used to drive the spiral groove to restrict the swing of the protruding part, which solves the problem of unstable adjustment of the presser foot height in the sewing machine, and realizes convenient and reliable adjustment of the presser foot height and simplifies user operation.
Patent Information
- Application Number
- CN202010569431.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-20
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2040-06-20
AI Technical Summary
The height adjustment of the presser foot in existing sewing machines is unstable, and the user is inconvenient to operate. It requires turning multiple knobs to adjust the height of the presser foot, which leads to complex and inconvenient operation.
The spiral groove and protruding structure is adopted. The spiral groove is driven by the rotation shaft to limit the swing of the protruding part, and the rotation of the presser foot lifting and adjustment shaft is realized. Users only need to rotate the rotation shaft to adjust the presser foot height, ensuring the stability and convenience of height adjustment. sex.
It realizes convenient and reliable adjustment of presser foot height, reduces operating complexity, and improves the stability of presser foot height adjustment. Users can complete height adjustment by simply rotating the shaft.
Smart Images
Figure CN111593500B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sewing machines, and in particular relates to a sewing machine. Background Art
[0002] In order to prevent the fabric from rising with the needle due to friction with the needle and interfering with sewing, a presser foot assembly is installed on each industrial sewing machine. When the needle bar leaves the fabric and rises, the presser foot assembly is used to press the fabric downward to prevent the needle from lifting the fabric upward. After the needle completely leaves the fabric and rises, the presser foot assembly rises with the needle bar. In early industrial sewing machines, the lifting height of the presser foot assembly was a fixed value and could not be adjusted. However, with the continuous improvement of industrial sewing machine technology, there is also a requirement for the adjustability of the lifting height of the presser foot assembly.
[0003] In order to solve the problem of adjustable presser foot assembly, a Chinese patent (application number CN201610850296.5) proposes a height adjustment mechanism and a sewing machine having the same. The solution for adjusting the height of the presser foot in the patent is to drive the presser foot lifting adjustment shaft to rotate to a certain angle through the adjustment mechanism to adjust the distance between the axis between the connecting part and the main shaft, and then adjust the swing amplitude of the cam connecting crank to adjust the height of the presser foot. The adjustment mechanism includes a first operating knob, a second connecting shaft and a first cam connected to the second connecting shaft. The first operating knob is rotated to cooperate with the first protrusion located on the presser foot lifting adjustment shaft to rotate the presser foot lifting adjustment shaft. After the presser foot lifting adjustment shaft rotates, it is necessary to combine the auxiliary adjustment mechanism with the second protrusion to limit the stop so that the presser foot lifting adjustment shaft rotates within a preset angle. The auxiliary adjustment mechanism includes a second operating knob, a third connecting shaft and a second cam connected to the third connecting shaft, and the second cam is in contact with the second protrusion. In the above patent, if the presser foot height is adjusted, the first operating knob and the second operating knob need to be turned to make the presser foot lifting adjustment shaft rotate and adjust to limit the position, so as to avoid the presser foot lifting adjustment shaft rotating during the operation of the sewing machine, resulting in unstable presser foot height adjustment.
[0004] In the above patent, if the height adjustment of the pressing foot body is to be stable, two knobs need to be turned to limit the rotation of the lifting adjustment shaft of the pressing foot body. There are many parts and it is inconvenient for the user to operate. Summary of the invention
[0005] The purpose of the present invention is to solve the above problems in the prior art and to propose a sewing machine. The technical problem to be solved by the present invention is: how to enable the user to adjust the presser foot height more conveniently and reliably.
[0006] The purpose of the present invention can be achieved by the following technical solutions:
[0007] A sewing machine comprises a casing, wherein a presser foot assembly including a presser foot body is arranged at the head of the casing, an upper shaft is arranged in the casing, the upper shaft and the presser foot assembly are connected through a presser foot interaction transmission mechanism, the presser foot interaction transmission mechanism comprises a presser foot lifting shaft bracket, a presser foot lifting adjustment shaft is also connected to the presser foot lifting shaft bracket, a rotating shaft capable of driving the presser foot lifting adjustment shaft to rotate is also arranged in the casing, and the character is that a spiral groove is provided on the outer side surface of the rotating shaft along its axial direction, a first protrusion capable of rotating synchronously with the presser foot lifting adjustment shaft is fixedly provided on the presser foot lifting adjustment shaft, the first protrusion extends into the spiral groove, and the first protrusion and the spiral groove are clearance-matched.
[0008] The upper shaft drives the presser foot body to be lifted or lowered in the working state of the sewing machine through the presser foot interaction transmission mechanism. The rotation of the rotating shaft causes the spiral groove to rotate accordingly, and the first protrusion located in the spiral groove swings upward or downward with the rotation of the spiral groove, thereby driving the presser foot lifting adjustment shaft to rotate, so that the presser foot lifting adjustment shaft can be rotated by a certain angle by rotating the rotating shaft, thereby adjusting the distance between the presser foot lifting shaft bracket and the upper shaft, realizing the swing adjustment of the presser foot interaction transmission mechanism, and then adjusting the movement amplitude of the presser foot interaction transmission mechanism to the presser foot assembly, and indirectly adjusting the movement amplitude of the presser foot assembly. If the force generated by the presser foot lifting adjustment shaft during the operation of the sewing machine drives the first protrusion to swing upward or downward, the first protrusion is restricted from swinging upward or downward by a large amplitude because it is located in the spiral groove and is in a clearance fit state with the spiral groove, thereby limiting the freedom of rotation of the presser foot lifting adjustment shaft, so that the presser foot lifting adjustment shaft can only be driven to rotate under the active rotation of the rotating shaft to adjust the height of the presser foot body. Therefore, the user only needs to rotate the rotating shaft to adjust the height of the presser foot body, and the presser foot assembly has good stability after the height is adjusted, making it more convenient and reliable for the user to adjust the height of the presser foot body.
[0009] In the above sewing machine, the rotating shaft includes a core shaft and a sleeve sleeved on the core shaft, the sleeve is fixedly connected to the core shaft, and the spiral groove is provided on the outer wall of the sleeve. According to the actual demand for the rotation range of the presser foot lifting adjustment shaft, only the sleeve on the core shaft is replaced, saving production costs.
[0010] In the above-mentioned sewing machine, the spiral groove includes an upper side wall, a lower side wall and a groove bottom wall connecting the upper side wall and the lower side wall, the groove width of the spiral groove is the same as the groove bottom wall width, and the first protrusion is located between the upper side wall and the lower side wall. The rotation of the shaft drives the spiral groove to rotate, and when the presser foot interaction amount needs to be increased, the shaft is rotated to make the upper side wall of the spiral groove abut against the first protrusion, the upper side wall applies downward pressure to the first protrusion, and the first protrusion swings downward; when the presser foot interaction amount needs to be reduced, the shaft is rotated to make the lower side wall of the spiral groove abut against the first protrusion, the lower side wall applies an upward lifting force to the first protrusion, and the first protrusion swings upward.
[0011] In the above-mentioned sewing machine, a torsion spring is sleeved on the presser foot lifting and adjusting shaft to make the first protrusion abut against the upper side wall or the lower side wall, and two force arms of the torsion spring abut against or are connected to the inner wall of the casing and the presser foot lifting and adjusting shaft respectively. The two force arms of the torsion spring abut against or are connected to the inner wall of the casing and the presser foot lifting and adjusting shaft respectively, so that the presser foot lifting and adjusting shaft generates a rotation torque, thereby making the first protrusion always abut against the upper side wall or the lower side wall of the spiral groove, further ensuring that the presser foot lifting and adjusting shaft is stable and does not rotate in the working state, thereby making the height adjustment of the presser foot body reliable and convenient.
[0012] In the above sewing machine, the first protrusion is in the shape of a rod, a plug-in hole 1 is provided on the presser foot lifting and adjusting shaft, the rod-shaped first protrusion is located in the plug-in hole 1, and a limit stop ring is provided on the rod-shaped first protrusion that can abut against the outer peripheral surface of the presser foot lifting and adjusting shaft. The rod-shaped first protrusion is plugged into the plug-in hole 1 of the presser foot lifting and adjusting shaft, and the plug-in depth of the rod-shaped first protrusion plugged into the presser foot lifting and adjusting shaft is achieved by the limit stop ring.
[0013] In the above sewing machine, the end of the first protrusion located in the spiral groove is spherical, and the end of the first protrusion located in the spiral groove is in point contact with the upper side wall or the lower side wall of the spiral groove. The end of the first protrusion located in the spiral groove is spherical, which reduces the contact area between the first protrusion and the spiral groove, thereby reducing the resistance of the user when rotating the shaft.
[0014] In the above-mentioned sewing machine, a second protrusion is further provided on the outer peripheral wall of the presser foot lifting adjustment shaft, one end of the torsion spring abuts against the inner wall of the casing, and the other end is fixedly connected or abuts against the second protrusion, the second protrusion is in the shape of a rod, and the presser foot lifting adjustment shaft is provided with a plug hole 2 parallel to the plug hole 1, the rod-shaped second protrusion is located in the plug hole 2, and the second protrusion is located in the opposite direction of the protrusion of the first protrusion on the presser foot lifting adjustment shaft. The two ends of the torsion spring abut against the casing and the second protrusion respectively, and the force of the torsion spring is applied to the second protrusion, the plug hole 1 and the plug hole 2 are arranged in parallel on the presser foot lifting adjustment shaft, so that the presser foot lifting adjustment shaft can realize the opening of the plug hole 1 and the plug hole 2 on one processing station for easy processing, and the protrusion of the protrusion 1 and the protrusion 2 are in opposite directions, so that the torque of the torsion spring acting on the presser foot lifting adjustment shaft can be better applied to the protrusion 1.
[0015] In the above sewing machine, the top of the rotating shaft passes through the top surface of the housing and is connected to a knob, the top surface of the housing has an annular boss, and the bottom of the knob is located inside the annular boss. The knob can facilitate the user to rotate the rotating shaft, and the annular boss can limit the position of the knob.
[0016] In the above sewing machine, the bottom of the knob has an outwardly folded edge, the upper surface of the edge has a scale mark, and the annular boss is provided with an indication notch that runs through the inner wall and the outer wall. The scale mark on the edge matches the indication notch on the annular boss, and when the knob is turned, the scale mark uses the notch as a reference, so that the user knows the range of rotation.
[0017] In the above sewing machine, the torsion spring is located between the first protrusion and the second protrusion. The torsion spring is located between the first protrusion and the second protrusion, so that the force of the torsion spring can be better transmitted between the first protrusion and the second protrusion.
[0018] Compared with the prior art, this sewing machine has the following advantages:
[0019] 1. The height of the pressing body can be adjusted by simply rotating the shaft, which is convenient for users to operate.
[0020] 2. The first protrusion on the presser foot lifting and adjusting shaft is located in the spiral groove, and the upward or downward swinging amplitude of the first protrusion is limited by the top and bottom surfaces of the spiral groove, thereby limiting the freedom of rotation of the presser foot lifting and adjusting shaft.
[0021] 3. By setting the torsion spring, pressure is applied to the first protrusion so that it always abuts against the upper side wall or the lower side wall of the spiral groove. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the overall structure of this sewing machine.
[0023] Figure 2 It is a structural schematic diagram of the sewing machine with part of the housing removed.
[0024] Figure 3 This is a schematic diagram of the structure of the sewing machine when all the shells are removed and viewed from the front to the rear.
[0025] Figure 4 yes Figure 3 A partial enlarged view of .
[0026] Figure 5 This is a schematic diagram of the structure of the sewing machine when all the shells are removed and viewed from the tail to the head.
[0027] Figure 6 yes Figure 5 A partial enlarged view of .
[0028] Figure 7 It is a schematic diagram of the structure of the sleeve.
[0029] In the figure, 1, casing; 1a, annular boss; 1a1, indicating notch; 2, presser foot assembly; 2a, presser foot body; 3, upper shaft; 4, presser foot interaction transmission mechanism; 4a, presser foot lifting shaft bracket; 5, presser foot lifting adjustment shaft; 5a, plug-in hole one; 5b, plug-in hole two; 6, rotating shaft; 7, spiral groove; 7a, upper side wall; 7b, lower side wall; 7c, groove bottom wall; 8, first protrusion; 8a, limit stop ring; 9, second protrusion; 10, sleeve; 11, torsion spring; 12, knob; 13 core shaft. DETAILED DESCRIPTION
[0030] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0031] Embodiment 1:
[0032] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, the sewing machine comprises a casing 1, and a presser foot assembly 2 is arranged at the head of the casing 1, and the presser foot assembly 2 comprises a pressure-adjusting locking nut, a pressure-adjusting screw, a pressure rod, a pressure rod sleeve, a presser foot connecting rod, a presser foot feeding crank, a presser foot feeding crank bracket, a presser foot lifting shaft, a presser foot lifting shaft left sleeve, a presser foot lifting shaft left sleeve and a presser foot body 2a. The presser foot connecting rod and the pressure rod are connected to the presser foot body 2a, and the pressure rod is provided with an upper sleeve connected with a pressure rod sleeve, a pressure rod guide frame, a pressure-adjusting locking nut and a pressure-adjusting screw from the bottom. The top of the presser foot connecting rod is connected with a presser foot feeding crank bracket and a presser foot feeding crank, and the presser foot feeding crank is L-shaped, and a feed crank connecting rod is also connected between the presser foot feeding crank and the pressure rod guide frame, and a presser foot feeding crank connecting rod is also connected to the top of the presser foot feeding crank.
[0033] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, the presser foot interaction amount transmission mechanism 4 includes a presser foot lifting shaft, the front end of the presser foot lifting shaft is connected to the presser foot feeding crank connecting rod, the tail end of the presser foot lifting shaft is connected to the presser foot lifting shaft bracket 4a crank, the presser foot lifting shaft bracket 4a crank is connected to the adjusting crank connecting rod, the adjusting crank connecting rod is also connected to the cloth feeding cam crank, the cloth feeding cam crank is connected to the upper shaft 3, the connection between the presser foot lifting shaft bracket 4a crank and the cloth feeding cam crank is also commonly connected to the adjusting crank shaft, the adjusting crank shaft has two connecting arms, the adjusting crank connecting rod and the cloth feeding cam crank are located between the two connecting arms of the adjusting crank shaft, and the adjusting crank shaft is connected to the presser foot lifting shaft bracket 4a.
[0034] like Figures 2 to 7As shown, the rear side of the presser foot lifting shaft bracket 4a is connected with a presser foot lifting adjustment shaft 5, and the presser foot lifting adjustment shaft 5 is located above the upper shaft 3. A rotating shaft 6 is arranged vertically with the presser foot lifting adjustment shaft 5 in the housing 1, and the top of the rotating shaft 6 passes through the top of the housing 1 and is connected with a knob 12. The rotating shaft 6 includes a core shaft 13 and a sleeve 10 sleeved on the core shaft 13. The sleeve 10 is fixedly connected to the core shaft 13. The sleeve 10 and the core shaft 13 are connected by a fastener. The fastener passes through the outer wall and the inner wall of the sleeve 10 and is screwed on the core shaft 13. A spiral spiral groove 7 is opened on the outer surface of the sleeve 10 along its axial direction. The structural shape of the spiral groove 7 is similar to the thread groove on the screw. The outer peripheral wall of the presser foot lifting and adjusting shaft 5 is provided with a first protrusion 8 extending into the spiral groove 7. The spiral groove 7 includes an upper side wall 7a, a lower side wall 7b and a groove bottom wall 7c connecting the upper side wall 7a and the lower side wall 7b. The groove width of the spiral groove 7 is the same as the width of the groove bottom wall 7c. The first protrusion 8 is located between the upper side wall 7a and the lower side wall 7b. There is a gap between the first protrusion 8 and the upper side wall 7a, and there is also a gap between the first protrusion 8 and the lower side wall 7b. The size of the first protrusion 8 located in the spiral groove 7 is slightly smaller than the groove width of the spiral groove 7. The spiral groove 8 has a starting point and an end point on the sleeve 10, and the starting point of the spiral groove 8 is higher than the end point of the spiral groove 8.
[0035] like Figures 2 to 7As shown, the rotation of the rotating shaft 6 drives the spiral groove 7 to rotate. When the presser foot interaction amount needs to be increased, the rotating shaft 6 is rotated to make the upper side wall 7a of the spiral groove 7 abut against the first protrusion 8, and the upper side wall 7a applies downward pressure to the first protrusion 8, so that the first protrusion 8 swings downward; when the presser foot interaction amount needs to be reduced, the rotating shaft 6 is rotated to make the lower side wall 7b of the spiral groove 7 abut against the first protrusion 8, and the lower side wall 7b applies an upward lifting force to the first protrusion 8, so that the first protrusion 8 swings upward, thereby driving the presser foot lifting adjustment shaft 5 to rotate, so that the presser foot lifting adjustment shaft 5 can be rotated by a certain angle by rotating the rotating shaft 6. The presser foot lifting adjustment shaft 5 drives the presser foot lifting shaft bracket 4a to rotate, and the rotation of the presser foot lifting shaft bracket 4a drives the adjustment crank shaft to rotate. The adjusting crank shaft and the presser foot lifting shaft bracket 4a have two connection points. The presser foot lifting shaft bracket 4a rotates to adjust the distance between one of the two connection points and the upper shaft 3, so as to adjust the height of the presser foot body 2a and the swing amplitude of the presser foot interaction transmission mechanism 4, thereby adjusting the movement amplitude transmitted to the presser foot assembly 2 by the presser foot interaction transmission mechanism 4, and indirectly adjusting the movement amplitude of the presser foot assembly 2. If the presser foot lifting adjustment shaft 5 generates a rotating force to drive the first protrusion 8 to swing upward or downward during the operation of the sewing machine, the first protrusion 8 is restricted from swinging upward or downward because it is located in the spiral groove 7 and abuts against its upper side wall 7a or lower side wall 7b, thereby limiting the freedom of rotation of the presser foot lifting adjustment shaft 5, so that the presser foot lifting adjustment shaft 5 can only be driven to rotate when the rotating shaft 6 actively rotates to adjust the height of the presser foot body 2a. Therefore, the user only needs to rotate the rotating shaft 6 to adjust the height of the presser foot body 2a, and the presser foot assembly 2 has good stability after the height is adjusted, making it more convenient and reliable for the user to adjust the height of the presser foot body 2a.
[0036] like Figures 2 to 7 As shown, a torsion spring 11 is sleeved on the presser foot lifting and adjusting shaft 5, which can make the first protrusion 8 abut against the upper side wall 7a or the lower side wall 7b of the spiral groove 7. One of the force arms of the torsion spring 11 abuts against or is connected to the inner wall of the casing 1, and the other force arm is connected to the presser foot lifting and adjusting shaft 5, so that the presser foot lifting and adjusting shaft 5 generates a rotational torque, so that the first protrusion 8 always abuts against the upper side wall 7a or the lower side wall 7b of the spiral groove 7, further ensuring that the presser foot lifting and adjusting shaft 5 is stable and does not rotate in the working state, thereby making the height adjustment of the presser foot body 2a reliable and convenient.
[0037] like Figures 2 to 7As shown, the first protrusion 8 is in the shape of a rod, and a plug-in hole 5a is provided on the presser foot lifting and adjusting shaft 5. The rod-shaped first protrusion 8 is located in the plug-in hole, and the rod-shaped first protrusion 8 is provided with a limit ring 8a that can abut against the outer peripheral surface of the presser foot lifting and adjusting shaft 5. The first protrusion 8 is separately set and connected with the presser foot lifting and adjusting shaft 5. Compared with reserving the first protrusion by a milling machine or other processing technology during the processing of the presser foot lifting and adjusting shaft 5, the form of the first protrusion 8 being separately set and connected with the presser foot lifting and adjusting shaft 5 is more economical and easier to process. The plug-in depth of the rod-shaped first protrusion 8 plugged into the presser foot lifting and adjusting shaft 5 is achieved by the limit ring 8a. The end of the first protrusion 8 located in the spiral groove 7 is spherical, and the end of the first protrusion 8 located in the spiral groove 7 is in point contact with the upper side wall 7a or the lower side wall 7b of the spiral groove 7. The end of the first protrusion 8 located in the spiral groove 7 is spherical, which reduces the contact area between the first protrusion 8 and the spiral groove 7, thereby reducing the resistance of the user when rotating the shaft 6.
[0038] like Figure 2 As shown, the top surface of the housing 1 has an annular boss 1a, the bottom of the knob 12 is inside the annular boss 1a, the bottom of the knob 12 has an outwardly folded edge, the upper surface of the edge has a scale mark, and the annular boss 1a has an indication notch 1a1 that runs through its inner wall and outer wall. The annular boss 1a can limit the position of the knob 12, the scale mark on the edge matches the indication notch 1a1 on the annular boss 1a, and when the knob 12 is turned, the scale mark uses the notch as a reference, so that the user knows the range of rotation.
[0039] Embodiment 2:
[0040] This embodiment is substantially the same as the first embodiment, except that Figures 2 to 5 As shown, the presser foot lifting and adjusting shaft 5 is also provided with a second protrusion 9, which is in the shape of a rod. The presser foot lifting and adjusting shaft 5 is provided with a second plug hole 5b parallel to the first plug hole 5a. The parallel arrangement of the first plug hole 5a and the second plug hole 5b can facilitate processing at a punching station. The rod-shaped second protrusion 9 is located at the second plug hole 5b. The second protrusion 9 and the first protrusion 8 are located on the presser foot lifting and adjusting shaft 5 in opposite directions. One end of the torsion spring 11 abuts against the inner wall of the housing 1, and the other end is fixedly connected or abutted against the second protrusion 9. The protrusion directions of the first protrusion and the second protrusion are opposite, so that the torque of the torsion spring 11 acting on the presser foot lifting and adjusting shaft 5 can be better applied to the protrusion 1. The torsion spring 11 is located between the first protrusion 8 and the second protrusion 9. The torsion spring 11 is located between the first protrusion 8 and the second protrusion 9, so that the force of the torsion spring 11 can be better transmitted between the first protrusion 8 and the second protrusion 9.
[0041] Embodiment three:
[0042] This embodiment is substantially the same as the second embodiment, the difference being that the spiral groove 7 is directly machined on the outer surface of the shaft 6, and the first protrusion 8 and the second protrusion 9 are both directly reserved during the machining of the shaft 6 and are machined by a milling machine or a machining center.
[0043] Embodiment 4:
[0044] This embodiment is substantially the same as the first embodiment, except that the core shaft 13 and the sleeve 10 sleeved on the core shaft 13 are fixedly connected together by welding.
[0045] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.
Claims
1. A sewing machine, comprising a casing (1), a presser foot assembly (2) comprising a presser foot body (2a) being arranged at the head of the casing (1), an upper shaft (3) being arranged in the casing (1), the upper shaft (3) being connected to the presser foot assembly (2) via a presser foot interaction transmission mechanism (4), the presser foot interaction transmission mechanism (4) comprising a presser foot lifting shaft bracket (4a), a presser foot lifting adjustment shaft (5) being connected to the presser foot lifting shaft bracket (4a), a rotating shaft (6) being arranged in the casing (1) and capable of driving the presser foot lifting adjustment shaft (5) to rotate, characterized in that: A spiral groove (7) is provided on the outer side surface of the rotating shaft (6) along its axial direction; a first protrusion (8) which can rotate synchronously with the rotating shaft (6) is fixedly provided on the presser foot lifting and adjusting shaft (5); the first protrusion (8) extends into the spiral groove (7); the first protrusion (8) and the spiral groove (7) are clearance-matched; the spiral groove (7) comprises an upper side wall (7a) and a lower side wall (7b); the first protrusion (8) is located between the upper side wall (7a) and the lower side wall (7b); a torsion spring (11) is sleeved on the presser foot lifting and adjusting shaft (5) so that the first protrusion (8) abuts against the upper side wall (7a) or the lower side wall (7b); the first protrusion (8) is in the shape of a rod; the presser foot lifting and adjusting shaft (5) is provided with a torsion spring (11) which ... The lifting adjustment shaft (5) is provided with a plug hole 1 (5a), a rod-shaped first protrusion (8) is located in the plug hole 1 (5a), and a second protrusion (9) is also provided on the outer peripheral wall of the presser foot lifting adjustment shaft (5), one end of the torsion spring (11) is in contact with the inner wall of the casing (1), and the other end is fixedly connected to or in contact with the second protrusion (9), the second protrusion (9) is rod-shaped, and the presser foot lifting adjustment shaft (5) is provided with a plug hole 2 (5b) parallel to the plug hole 1 (5a), the rod-shaped second protrusion (9) is located in the plug hole 2 (5b), and the second protrusion (9) and the first protrusion (8) are located on the presser foot lifting adjustment shaft (5) in opposite protrusion directions.
2. The sewing machine according to claim 1, characterized in that: The rotating shaft (6) comprises a core shaft (13) and a sleeve (10) sleeved on the core shaft (13); the sleeve (10) is fixedly connected to the core shaft (13); the sleeve (10) and the core shaft (13); and the spiral groove (7) is provided on the outer wall of the sleeve (10).
3. The sewing machine according to claim 1 or 2, characterized in that: The spiral groove (7) further comprises a groove bottom wall (7c) connecting the upper side wall (7a) and the lower side wall (7b); the groove opening width of the spiral groove (7) is the same as the width of the groove bottom wall (7c).
4. The sewing machine according to claim 1, characterized in that: The rod-shaped first protrusion (8) is provided with a limit stop ring (8a) capable of abutting against the outer peripheral surface of the presser foot lifting adjustment shaft (5).
5. The sewing machine according to claim 4, characterized in that The end of the first protrusion (8) located in the spiral groove (7) is spherical, and the end of the first protrusion (8) located in the spiral groove (7) is in point contact with the upper side wall (7a) or the lower side wall (7b) of the spiral groove (7).
6. The sewing machine according to claim 1, characterized in that The top end of the rotating shaft (6) passes through the top surface of the housing (1) and is connected to a knob (12). The top surface of the housing (1) is provided with an annular boss (1a), and the bottom of the knob (12) is located inside the annular boss (1a).
7. The sewing machine according to claim 6, characterized in that The bottom of the knob (12) has an outwardly folded edge, the upper surface of the edge has a scale mark, and the annular boss (1a) is provided with an indicating notch (1a1) that runs through the inner wall and the outer wall thereof.
8. The sewing machine according to claim 1, characterized in that The torsion spring (11) is located between the first protrusion (8) and the second protrusion (9).