Height adjustment mechanism and sewing machine having the same

Abstract

The present invention provides a height adjustment mechanism and a sewing machine having the same. The height adjustment mechanism comprises: an adjustment assembly, comprising an adjustment structure, a crank shaft and a transition connection structure arranged on the crank shaft, the adjustment structure drives the crank shaft to rotate along a first preset direction, the transition connection structure comprises a connection portion eccentrically arranged with the axis of the crank shaft; a main shaft, parallel to the crank shaft; a presser foot assembly, comprising a presser foot and a transmission structure, the transmission structure drives the presser foot to move up and down; a main shaft transmission assembly, the transmission structure is connected to the main shaft through the main shaft transmission assembly, the main shaft transmission assembly comprises a cam connection crank, the cam connection crank is connected to the connection portion and swings around the connection between the two; the adjustment structure drives the crank shaft to rotate a certain angle to adjust the distance between the connection portion and the axis of the main shaft, and then adjusts the swing amplitude of the cam connection crank to adjust the height range of the presser foot movement. The present invention solves the problem that the adjustment of the presser foot height of the sewing machine in the prior art is relatively cumbersome.

Description

Technical Field

[0001] The present invention relates to the technical field of sewing machines, and in particular to a height adjustment mechanism and a sewing machine having the same. Background Art

[0002] At present, when a user uses a sewing machine, the user needs to adjust the height of the presser foot according to different requirements of the sewing materials, so that the height of the presser foot is suitable for the thickness of the sewing materials.

[0003] However, in the prior art, the adjustment of the presser foot height of the sewing machine is relatively cumbersome and complicated, which increases the labor intensity of the staff. Summary of the invention

[0004] The main purpose of the present invention is to provide a height adjustment mechanism and a sewing machine having the same, so as to solve the problem in the prior art that the adjustment of the presser foot height of the sewing machine is relatively cumbersome and complicated, which increases the labor intensity of the staff.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a height adjustment mechanism is provided, which is used to adjust the height of the presser foot of a sewing machine, and the height adjustment mechanism comprises: an adjustment assembly, comprising an adjustment structure, a crank shaft and a transition connection structure arranged on the crank shaft, the adjustment structure drives the crank shaft to rotate along a first preset direction, the transition connection structure comprises a connection portion eccentrically arranged with the axis of the crank shaft; a main shaft, the main shaft is arranged parallel to the crank shaft; a presser foot assembly, comprising a presser foot and a transmission structure connected to the presser foot, the transmission structure drives the presser foot to perform lifting and lowering movements; a main shaft transmission assembly, the transmission structure is connected to the main shaft through the main shaft transmission assembly, the main shaft transmission assembly comprises a cam-connected crank, the cam-connected crank is connected to the connection portion and swings around the connection between the two; wherein, the adjustment structure drives the crank shaft to rotate a certain angle to adjust the distance between the connection portion and the axis of the main shaft, and then adjusts the swing amplitude of the cam-connected crank to adjust the height range of the presser foot movement.

[0006] Furthermore, the connecting portion has a mounting hole, and the transition connection structure also includes: a first connecting shaft, which passes through the cam connecting crank and is fixed in the mounting hole, the first connecting shaft is arranged parallel to the crank shaft, and the cam connecting crank is swingably arranged around the first connecting shaft.

[0007] Furthermore, the main shaft transmission assembly also includes: an eccentric wheel, which is sleeved on the main shaft and rotates synchronously with the main shaft; an eccentric wheel connecting rod, which is arranged on the eccentric wheel and is pivotally connected to the cam connecting crank to drive the cam connecting crank to swing; a connecting rod, a first end of the connecting rod is pivotally connected to the eccentric wheel connecting rod, and a second end of the connecting rod is connected to the transmission structure, and the eccentric wheel connecting rod drives the transmission structure to move through the connecting rod, so as to drive the presser foot to perform lifting and lowering movements through the transmission structure; wherein, the cam connecting crank is pivotally connected to the eccentric wheel connecting rod.

[0008] Furthermore, the transmission structure includes: a presser foot lifting crank, which is connected to the second end of the connecting rod; a presser foot lifting crank shaft, on which the presser foot lifting crank is eccentrically arranged; a presser foot lifting mechanism, through which the presser foot is connected to the presser foot lifting crank shaft, and during the rotation of the presser foot lifting crank shaft, the presser foot lifting crank shaft drives the presser foot to perform lifting and lowering movements through the presser foot lifting mechanism.

[0009] Furthermore, the adjustment structure includes a first cam, and the adjustment assembly also includes: a first protrusion, which is arranged on the crank shaft, so that the first cam contacts the first protrusion and drives the first protrusion to rotate along a first preset direction by rotating the adjustment structure to realize the rotation of the crank shaft.

[0010] Furthermore, the outer peripheral surface of the first cam is a first arc-shaped surface, and the adjustment structure also includes: a first operating knob; a second connecting shaft, and the first cam is connected to the first operating knob through the second connecting shaft, so that the first cam can rotate around the axis of the second connecting shaft by rotating the first operating knob; wherein, along the extension direction of the first arc-shaped surface, the center line of the first arc-shaped surface is arranged parallel to the axis of the second connecting shaft, and the distance between the center line and the axis gradually increases or decreases.

[0011] Furthermore, the height adjustment mechanism also includes: an auxiliary adjustment component, the auxiliary adjustment component includes an auxiliary adjustment structure and a second protrusion arranged on the crank shaft, the auxiliary adjustment structure and the second protrusion limit stop to allow the crank shaft to rotate within a preset angle.

[0012] Furthermore, the auxiliary adjustment structure includes: a second operating knob; a third connecting shaft; a second cam, wherein the second cam is connected to the second operating knob via the third connecting shaft so that the second cam can be rotated along a second preset direction by rotating the second operating knob, so that the second cam rotates around the axis of the third connecting shaft; wherein the outer peripheral surface of the second cam is a second arc surface, and along the extension direction of the second arc surface, the center line of the second arc surface is arranged parallel to the axis of the third connecting shaft, and the distance between the center line and the axis gradually increases or decreases.

[0013] Furthermore, the height adjustment mechanism also includes: a torsion spring, which is arranged on the crank shaft, and a torsion spring arm of the torsion spring is connected to the casing to prevent the crank shaft from moving along its radial direction.

[0014] Further, the torsion spring is located between the first protrusion and the second protrusion, and two ends of the torsion spring are respectively in contact with the first protrusion and the second protrusion.

[0015] According to another aspect of the present invention, a sewing machine is provided, comprising a casing and a height adjustment mechanism, wherein at least a portion of the height adjustment mechanism is located inside the casing; wherein the height adjustment mechanism is the above-mentioned height adjustment mechanism.

[0016] According to the technical solution of the present invention, the adjustment component includes an adjustment structure, a crankshaft and a transition connection structure arranged on the crankshaft, the adjustment structure drives the crankshaft to rotate along a first preset direction, and the transition connection structure includes a connection portion eccentrically arranged with the axis of the crankshaft. The main shaft is arranged in parallel with the crankshaft. In this way, when the user needs to adjust the height of the presser foot, the adjustment structure is operated so that the adjustment structure drives the crankshaft to rotate a certain angle, and then the distance between the connection portion and the axis of the main shaft is adjusted to adjust the swing amplitude of the cam-connected crank, and then the movement amplitude of the transmission structure connected to the presser foot is adjusted, and the height range of the presser foot movement is indirectly adjusted, so that the user can adjust the height of the presser foot more easily, that is, only the adjustment structure needs to be operated to rotate along the first preset direction, which solves the problem that the adjustment of the presser foot height of the sewing machine in the prior art is relatively cumbersome and complicated, and the labor intensity of the staff is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram showing a three-dimensional structure of an embodiment of a height adjustment mechanism according to the present invention; and

[0019] Figure 2 Shows Figure 1 A schematic diagram of the three-dimensional structure of the height adjustment mechanism from another angle.

[0020] The above drawings include the following reference numerals:

[0021] 20. Adjustment assembly; 21. Adjustment structure; 211. First cam; 212. First operating knob; 213. Second connecting shaft; 22. Crank shaft; 23. Transition connection structure; 231. Connection part; 232. First connecting shaft; 24. First protrusion; 30. Spindle; 40. Presser foot assembly; 41. Presser foot; 42. Transmission structure; 421. Presser foot lifting crank; 422. Presser foot lifting crank shaft; 423. Presser foot lifting mechanism; 50. Spindle transmission assembly; 51. Cam connecting crank; 52. Eccentric wheel; 53. Eccentric wheel connecting rod; 54. Connecting connecting rod; 60. Auxiliary adjustment assembly; 61. Auxiliary adjustment structure; 611. Second operating knob; 612. Third connecting shaft; 613. Second cam; 62. Second protrusion; 70. Torsion spring. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0024] In the present invention, unless otherwise specified, the directional words used, such as "up" and "down", usually refer to the directions shown in the drawings, or to the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0025] In order to solve the problem in the prior art that the adjustment of the presser foot height of a sewing machine is rather cumbersome and complicated, which increases the labor intensity of the staff, the present application provides a height adjustment mechanism and a sewing machine having the same.

[0026] like Figure 1 and Figure 2As shown, the height adjustment mechanism is used to adjust the height of the presser foot 41 of the sewing machine, and the height adjustment mechanism includes an adjustment assembly 20, a spindle 30, a presser foot assembly 40 and a spindle transmission assembly 50. Among them, the adjustment assembly 20 includes an adjustment structure 21, a crank shaft 22 and a transition connection structure 23 arranged on the crank shaft 22, the adjustment structure 21 drives the crank shaft 22 to rotate along a first preset direction, and the transition connection structure 23 includes a connection portion 231 eccentrically arranged with the axis of the crank shaft 22. The spindle 30 is arranged parallel to the crank shaft 22. The presser foot assembly 40 includes a presser foot 41 and a transmission structure 42 connected to the presser foot 41, and the transmission structure 42 drives the presser foot 41 to move up and down. The transmission structure 42 is connected to the spindle 30 through the spindle transmission assembly 50, and the spindle transmission assembly 50 includes a cam connection crank 51, and the cam connection crank 51 is connected to the connection portion 231 and swings around the connection between the cam connection crank 51 and the connection portion 231. The adjusting structure 21 drives the crank shaft 22 to rotate a certain angle to adjust the distance between the connecting portion 231 and the axis of the main shaft 30 , thereby adjusting the swing amplitude of the cam connecting crank 51 to adjust the height range of the presser foot 41 .

[0027] By applying the technical solution of this embodiment, when the user needs to adjust the height of the presser foot 41, the user operates the adjustment structure 21 so that the adjustment structure 21 drives the crank shaft 22 to rotate a certain angle, thereby adjusting the distance between the connecting portion 231 and the axis of the main shaft 30, so as to adjust the swing amplitude of the cam-connected crank 51, and then adjust the movement amplitude of the transmission structure 42 connected to the presser foot 41, and indirectly adjust the height range of the presser foot 41 movement, thereby making it easier for the user to adjust the height of the presser foot, that is, only need to operate the adjustment structure 21 to rotate along the first preset direction, thereby solving the problem that the adjustment of the presser foot height of the sewing machine in the prior art is relatively cumbersome and complicated, which increases the labor intensity of the staff.

[0028] In this embodiment, the adjustment structure 21 drives the crank shaft 22 to rotate a certain angle to adjust the shortest distance between the connecting portion 231 and the axis of the main shaft 30, so as to adjust the swing amplitude of the cam connecting crank 51, and then adjust the height range of the presser foot 41.

[0029] like Figure 2As shown, the connecting portion 231 has a mounting hole, and the transition connection structure 23 also includes a first connecting shaft 232. The first connecting shaft 232 passes through the cam connection crank 51 and is fixed in the mounting hole. The first connecting shaft 232 is arranged in parallel with the crank shaft 22, and the cam connection crank 51 is swingably arranged around the first connecting shaft 232. In this way, the connecting portion 231 and the cam connection crank 51 are connected together through the first connecting shaft 232 to realize the swing of the cam connection crank 51 around the first connecting shaft 232, so as to control the swing amplitude of the cam connection crank 51 by adjusting the shortest distance between the axis of the first connecting shaft 232 and the axis of the crank shaft 22, thereby adjusting the height range of the presser foot 41 driven by the transmission structure 42.

[0030] like Figure 1 and Figure 2 As shown, the main shaft transmission assembly 50 also includes an eccentric wheel 52, an eccentric wheel connecting rod 53 and a connecting rod 54. Among them, the eccentric wheel 52 is sleeved on the main shaft 30, and the eccentric wheel 52 rotates synchronously with the main shaft 30. The eccentric wheel connecting rod 53 is arranged on the eccentric wheel 52, and the eccentric wheel connecting rod 53 is pivotally connected with the cam connecting crank 51 to drive the cam connecting crank 51 to swing. The first end of the connecting rod 54 is pivotally connected with the eccentric wheel connecting rod 53, and the second end of the connecting rod 54 is connected with the transmission structure 42. The eccentric wheel connecting rod 53 drives the transmission structure 42 to move through the connecting rod 54, so as to drive the presser foot 41 to perform lifting movement through the transmission structure 42. Among them, the cam connecting crank 51 is pivotally connected with the eccentric wheel connecting rod 53. In this way, the above-mentioned arrangement ensures that the main shaft 30 can drive the cam connecting crank 51 to swing, thereby realizing the movement of the connecting rod 54 driving the transmission structure 42, and finally realizing the lifting movement of the presser foot 41 along its height direction.

[0031] Specifically, when the main shaft 30 rotates, the main shaft 30 drives the eccentric wheel 52 to rotate, and at the same time, the eccentric wheel 52 drives the eccentric wheel connecting rod 53 to rotate, one end of the cam connecting crank 51 swings around the first connecting shaft 232, the other end of the cam connecting crank 51 is pivotally connected to the eccentric wheel connecting rod 53, the first end of the connecting rod 54 is pivotally connected to the connecting portion of the cam connecting crank 51 and the eccentric wheel connecting rod 53, the second end of the connecting rod 54 is connected to the transmission structure 42, so as to drive the transmission structure 42 to move through the connecting rod 54, so as to drive the presser foot 41 connected to the transmission structure 42 to perform lifting and lowering movements, thereby ensuring that the height adjustment mechanism can operate normally, thereby improving the reliability of the height adjustment mechanism in adjusting the height of the presser foot 41.

[0032] like Figure 1 and Figure 2As shown, the transmission structure 42 includes a presser foot lifting crank 421, a presser foot lifting crank shaft 422 and a presser foot lifting mechanism 423. Among them, the presser foot lifting crank 421 is connected to the second end of the connecting rod 54. The presser foot lifting crank 421 is eccentrically arranged on the presser foot lifting crank shaft 422. The presser foot 41 is connected to the presser foot lifting crank shaft 422 through the presser foot lifting mechanism 423. During the rotation of the presser foot lifting crank shaft 422, the presser foot lifting crank shaft 422 drives the presser foot 41 to perform lifting motion through the presser foot lifting mechanism 423. In this way, the connecting rod 54 is pivotally connected to the presser foot lifting crank 421, and the presser foot lifting crank 421 is arranged on the presser foot lifting crank shaft 422, so as to drive the presser foot lifting crank shaft 422 to rotate through the presser foot lifting crank 421, thereby driving the presser foot lifting mechanism 423 to move, so as to realize the lifting motion of the presser foot 41.

[0033] Specifically, there is a preset distance between the connection point between the connecting rod 54 and the presser foot lifting crank 421 and the axis of the presser foot lifting crank shaft 422, so that the presser foot lifting crank shaft 422 can be driven to rotate eccentrically through the connecting rod 54, so that the presser foot lifting mechanism 423 drives the presser foot 41 to perform lifting and lowering movements, thereby ensuring that the height adjustment mechanism can realize the lifting and lowering movement of the presser foot 41.

[0034] like Figure 1 and Figure 2 As shown, the adjustment structure 21 includes a first cam 211, and the adjustment assembly 20 also includes a first protrusion 24. The first protrusion 24 is arranged on the crank shaft 22, so that the first cam 211 contacts the first protrusion 24 and drives the first protrusion 24 to rotate along a first preset direction by rotating the adjustment structure 21, so as to realize the rotation of the crank shaft 22. In this way, the above structure is simple in structure, easy to process and realize, and reduces the labor intensity of the staff.

[0035] Specifically, when the operating height range of the presser foot 41 needs to be adjusted, the first cam 211 is operated to rotate the first cam 211 along the first preset direction, thereby driving the first protrusion 24 in contact with it to move, thereby realizing the rotation of the crank shaft 22 around its axial direction, so as to adjust the shortest distance between the axis of the first connecting shaft 232 and the axis of the main shaft 30, and then adjust the swing amplitude of the cam-connected crank 51, and finally adjust the lifting and lowering height range of the presser foot 41.

[0036] like Figure 1 and Figure 2As shown, the outer peripheral surface of the first cam 211 is a first arc-shaped surface, and the adjustment structure 21 also includes a first operating knob 212 and a second connecting shaft 213. The first cam 211 is connected to the first operating knob 212 through the second connecting shaft 213, so that the first cam 211 rotates around the axis of the second connecting shaft 213 by rotating the first operating knob 212. Along the extension direction of the first arc-shaped surface, the center line of the first arc-shaped surface is arranged parallel to the axis of the second connecting shaft 213, and the distance between the center line and the axis gradually increases. In this way, the user can realize the rotation of the first cam 211 by twisting the first operating knob 212, thereby making it easier and simpler for the user to operate the adjustment structure 21, and reducing the difficulty of operation.

[0037] Specifically, when the user rotates the first operating knob 212 in the counterclockwise direction, the first operating knob 212 drives the first cam 211 to rotate in the counterclockwise direction, and the shortest distance between the center line of the first arc-shaped surface and the axis of the second connecting shaft 213 gradually increases to push the first protrusion 24 to rotate in the direction away from the first cam 211, that is, the crank shaft 22 rotates in the clockwise direction, and the shortest distance between the axis of the first connecting shaft 232 and the axis of the main shaft 30 decreases, thereby increasing the swing amplitude of the cam connecting crank 51, and the movement amplitude of the presser foot lifting crank 421 increases, and the lifting height range of the presser foot 41 increases; conversely, the lifting height range of the presser foot 41 decreases.

[0038] like Figure 1 and Figure 2 As shown, the height adjustment mechanism also includes an auxiliary adjustment component 60. The auxiliary adjustment component 60 includes an auxiliary adjustment structure 61 and a second protrusion 62 provided on the crank shaft 22. The auxiliary adjustment structure 61 and the second protrusion 62 are limited and stopped to allow the crank shaft 22 to rotate within a preset angle. In this way, the user can adjust the maximum rotation angle of the crank shaft 22 by adjusting the auxiliary adjustment component 60, so that the crank shaft 22 rotates within a preset angle range.

[0039] like Figure 1 As shown, the auxiliary adjustment structure 61 includes a second operating knob 611, a third connecting shaft 612 and a second cam 613. The second cam 613 is connected to the second operating knob 611 through the third connecting shaft 612, so that the second operating knob 611 can be rotated along the second preset direction to rotate the second cam 613 around the axis of the third connecting shaft 612. The outer peripheral surface of the second cam 613 is a second arc surface, and along the extension direction of the second arc surface, the center line of the second arc surface is arranged parallel to the axis of the third connecting shaft 612, and the distance between the center line and the axis gradually increases or decreases. In this way, the above-mentioned setting makes it easier and simpler for users to operate the auxiliary adjustment structure 61, and reduces the labor intensity of the staff.

[0040] Specifically, before the user adjusts the lifting height range of the presser foot 41, the user operates the second operating knob 611 to drive the second cam 613 to rotate through the second operating knob 611 and rotate to a preset position. After that, the user turns the first operating knob 212 and rotates it by a certain angle to drive the first protrusion 24 to rotate through the first cam 211. When the first protrusion 24 drives the crank shaft 22 to rotate to the limit stop between the second protrusion 62 and the second cam 613, the crank shaft 22 stops rotating, and the swing amplitude of the cam-connected crank 51 is adjusted to achieve the adjustment of the lifting height of the presser foot 41.

[0041] like Figure 1 and Figure 2 As shown, the height adjustment mechanism also includes a torsion spring 70. The torsion spring 70 is arranged on the crank shaft 22, and one torsion spring 70 arm of the torsion spring 70 is connected to the housing to prevent the crank shaft 22 from moving in its radial direction. In this way, when the user operates the adjustment structure 21 or the auxiliary adjustment component 60, or the main shaft 30 rotates, the torsion spring 70 can prevent the crank shaft 22 from moving in its radial direction, thereby improving the operating stability and reliability of the height adjustment mechanism. The torsion spring 70 is located between the first protrusion 24 and the second protrusion 62, and the two ends of the torsion spring 70 are respectively in contact with the first protrusion 24 and the second protrusion 62.

[0042] The present application also provides a sewing machine (not shown), comprising a housing and a height adjustment mechanism, wherein at least part of the height adjustment mechanism is located in the housing, wherein the height adjustment mechanism is the above-mentioned height adjustment mechanism.

[0043] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0044] When the user needs to adjust the height of the presser foot, the user operates the adjusting structure to make the adjusting structure drive the crank shaft to rotate a certain angle, thereby adjusting the distance between the connecting part and the axis of the main shaft to adjust the swing amplitude of the cam-connected crank, thereby adjusting the movement amplitude of the transmission structure connected to the presser foot, and indirectly adjusting the height range of the presser foot movement, thereby making it easier for the user to adjust the height of the presser foot, that is, only need to operate the adjusting structure to rotate along the first preset direction, thereby solving the problem that the adjustment of the presser foot height of the sewing machine in the prior art is relatively cumbersome and complicated, which increases the labor intensity of the staff.

[0045] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A height adjustment mechanism, the height adjustment mechanism being used to adjust the height of a presser foot (41) of a sewing machine, characterized in that: The height adjustment mechanism comprises: An adjustment assembly (20), comprising an adjustment structure (21), a crank shaft (22), and a transition connection structure (23) disposed on the crank shaft (22), wherein the adjustment structure (21) drives the crank shaft (22) to rotate along a first preset direction, and the transition connection structure (23) comprises a connection portion (231) disposed eccentrically with respect to the axis of the crank shaft (22); A main shaft (30), the main shaft (30) being arranged parallel to the crank shaft (22); A presser foot assembly (40), comprising the presser foot (41) and a transmission structure (42) connected to the presser foot (41), wherein the transmission structure (42) drives the presser foot (41) to perform lifting movement; A main shaft transmission assembly (50), wherein the transmission structure (42) is connected to the main shaft (30) via the main shaft transmission assembly (50), wherein the main shaft transmission assembly (50) comprises a cam connecting crank (51), wherein the cam connecting crank (51) is connected to the connecting portion (231) and swings around the connection between the two; The adjustment structure (21) drives the crank shaft (22) to rotate at a certain angle to adjust the distance between the connecting portion (231) and the axis of the main shaft (30), thereby adjusting the swing amplitude of the cam connecting crank (51) to adjust the height range of the presser foot (41); The adjustment structure (21) comprises a first cam (211), and the adjustment assembly (20) further comprises: A first protrusion (24) is arranged on the crank shaft (22), so that the first cam (211) contacts the first protrusion (24) and drives the first protrusion (24) to rotate along the first preset direction by rotating the adjustment structure (21), thereby realizing the rotation of the crank shaft (22); The outer peripheral surface of the first cam (211) is a first arc-shaped surface, and the adjustment structure (21) further comprises: A first operating knob (212); a second connecting shaft (213), wherein the first cam (211) is connected to the first operating knob (212) via the second connecting shaft (213), so that the first cam (211) is rotated around the axis of the second connecting shaft (213) by rotating the first operating knob (212); wherein, along the extension direction of the first arcuate surface, the center line of the first arcuate surface is arranged parallel to the axis of the second connecting shaft (213), and the distance between the center line and the axis gradually increases or gradually decreases; The height adjustment mechanism also includes: An auxiliary adjustment component (60), the auxiliary adjustment component (60) comprising an auxiliary adjustment structure (61) and a second protrusion (62) arranged on the crank shaft (22), the auxiliary adjustment structure (61) and the second protrusion (62) being limited and stopped so as to allow the crank shaft (22) to rotate within a preset angle; The auxiliary adjustment structure (61) comprises: A second operating knob (611); A third connecting shaft (612); a second cam (613), the second cam (613) being connected to the second operating knob (611) via the third connecting shaft (612), so that the second operating knob (611) can be rotated in a second preset direction, so that the second cam (613) rotates around the axis of the third connecting shaft (612); The outer peripheral surface of the second cam (613) is a second arcuate surface, and along the extension direction of the second arcuate surface, the center line of the second arcuate surface is arranged parallel to the axis of the third connecting shaft (612), and the distance between the center line and the axis gradually increases or decreases.

2. The height adjustment mechanism according to claim 1, characterized in that: The connecting portion (231) has a mounting hole, and the transition connection structure (23) further comprises: A first connecting shaft (232), the first connecting shaft (232) passes through the cam connecting crank (51) and is fixed in the mounting hole, the first connecting shaft (232) is arranged parallel to the crank shaft (22), and the cam connecting crank (51) is arranged swingably around the first connecting shaft (232).

3. The height adjustment mechanism according to claim 1, characterized in that: The main shaft transmission assembly (50) further comprises: An eccentric wheel (52) is sleeved on the main shaft (30), and the eccentric wheel (52) rotates synchronously with the main shaft (30); An eccentric wheel connecting rod (53) is arranged on the eccentric wheel (52), and the eccentric wheel connecting rod (53) is pivotally connected to the cam connecting crank (51) to drive the cam connecting crank (51) to swing; A connecting rod (54), wherein a first end of the connecting rod (54) is pivotally connected to the eccentric wheel connecting rod (53), and a second end of the connecting rod (54) is connected to the transmission structure (42); the eccentric wheel connecting rod (53) drives the transmission structure (42) to move via the connecting rod (54), so as to drive the presser foot (41) to perform a lifting movement via the transmission structure (42); wherein the cam connecting crank (51) is pivotally connected to the eccentric wheel connecting rod (53).

4. The height adjustment mechanism according to claim 3, characterized in that: The transmission structure (42) comprises: A presser foot lifting crank (421) connected to the second end of the connecting rod (54); A presser foot lifting crank shaft (422), the presser foot lifting crank (421) being eccentrically arranged on the presser foot lifting crank shaft (422); A presser foot lifting mechanism (423), wherein the presser foot (41) is connected to the presser foot lifting crank shaft (422) via the presser foot lifting mechanism (423), and during the rotation of the presser foot lifting crank shaft (422), the presser foot lifting crank shaft (422) drives the presser foot (41) to perform lifting movement via the presser foot lifting mechanism (423).

5. The height adjustment mechanism according to claim 1, characterized in that: The height adjustment mechanism also includes: A torsion spring (70) is arranged on the crankshaft (22), and one torsion spring (70) arm of the torsion spring (70) is connected to the casing to prevent the crankshaft (22) from moving in its radial direction.

6. The height adjustment mechanism according to claim 5, characterized in that: The torsion spring (70) is located between the first protrusion (24) and the second protrusion (62), and two ends of the torsion spring (70) are respectively in contact with the first protrusion (24) and the second protrusion (62).

7. A sewing machine, characterized in that: It comprises a casing and a height adjustment mechanism, wherein at least a part of the height adjustment mechanism is located in the casing; wherein the height adjustment mechanism is the height adjustment mechanism according to any one of claims 1 to 6.

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