CN110923967B

CN110923967B - Sewing machine trimming and thread loosening pressure foot lifting device and sewing machine

Info

Publication number: CN110923967B
Application number: CN201911334084.1A
Authority: CN
Inventors: 丁建明; 潘建国
Original assignee: Zhejiang Jieke Intelligent Sewing Technology Co ltd
Current assignee: ZHEJIANG JIEKE INTELLIGENT SEWING TECHNOLOGY Co.,Ltd.
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-12-14
Anticipated expiration: 2039-12-23
Also published as: CN110923967A

Abstract

The invention relates to the technical field of sewing machines, in particular to a thread trimming, thread loosening and presser foot lifting device of a sewing machine and the sewing machine comprising the device, wherein the device comprises: a power member; the cam structure is driven by the power piece to rotate and is provided with a first driving contour surface and a second driving contour surface; the trimming driving crank is connected with the trimming mechanism, a first driving pin is arranged on the trimming driving crank, the first driving pin is matched with a first driving contour surface, and the first driving contour surface is provided with a trimming driving section for driving the trimming mechanism to execute trimming; and one end of the ejector rod is provided with a second transmission pin, the other end of the ejector rod is connected with the thread loosening mechanism and the presser foot lifting mechanism, the second transmission pin is matched with a second driving contour surface, and the second driving contour surface is provided with a thread loosening driving section for driving the thread loosening mechanism to perform thread loosening action and a presser foot lifting driving section for driving the presser foot lifting mechanism to perform presser foot lifting action. The three functions of trimming, loosening and lifting the presser foot are realized by one power part.

Description

Sewing machine trimming and thread loosening pressure foot lifting device and sewing machine

Technical Field

The invention relates to the technical field of sewing machines, in particular to a thread cutting, thread loosening and presser foot lifting device of a sewing machine and the sewing machine.

Background

At present, the sewing machine can use the functions of thread cutting, thread loosening and presser foot lifting in the sewing process. The thread cutting function and the thread loosening function are achieved through electromagnet driving, and the problem of slow response exists; the presser foot lifting function is realized by driving modes such as a handle, a manual knee rest, an electromagnet, a cylinder and the like, and when the electromagnet is adopted for driving, the presser foot lifting function and the thread trimming function are respectively realized by driving the electromagnets with different powers. The driving mode for realizing three functions of trimming, loosening and lifting the presser foot has the defects of complex structure and low working precision.

Disclosure of Invention

The invention aims to solve the technical problem of providing a thread cutting, loosening and presser foot lifting device of a sewing machine, which has a simple structure and high working precision and overcomes the defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a thread trimming and loosening presser foot lifting device of a sewing machine comprises: a power member; the cam structure is driven by the power piece to rotate and is provided with a first driving contour surface and a second driving contour surface; the trimming driving crank is connected with the trimming mechanism, a first driving pin is arranged on the trimming driving crank, the first driving pin is matched with a first driving contour surface, and the first driving contour surface is provided with a trimming driving section for driving the trimming mechanism to execute trimming; and one end of the ejector rod is provided with a second transmission pin, the other end of the ejector rod is connected with the thread loosening mechanism and the presser foot lifting mechanism, the second transmission pin is matched with a second driving contour surface, and the second driving contour surface is provided with a thread loosening driving section for driving the thread loosening mechanism to perform thread loosening action and a presser foot lifting driving section for driving the presser foot lifting mechanism to perform presser foot lifting action.

Preferably, the cam structure comprises a first cam provided with a first drive profile and a second cam provided with a second drive profile.

Preferably, the power part is a double-output-shaft motor, and the first cam and the second cam are respectively arranged on the rotating shafts at two sides of the double-output-shaft motor.

Preferably, the thread cutting mechanism comprises a thread cutting driving shaft which is rotatably supported on a bottom plate of the sewing machine, the thread cutting driving crank is fixedly arranged on the thread cutting driving shaft, and the thread cutting driving shaft is connected with the thread cutting assembly.

Preferably, the thread cutting mechanism further comprises a thread cutting transmission crank fixedly arranged on the thread cutting driving shaft, a first sliding block hinged to the thread cutting transmission crank, and a thread cutting shaft rotatably supported on the bottom plate and parallel to the thread cutting driving shaft, a first sliding groove in sliding fit with the first sliding block is formed in one end of the thread cutting shaft, and the other end of the thread cutting shaft is connected with the thread cutting assembly.

Preferably, the ejector rod is connected with one end of a pressure foot lifting rear lever, the other end of the pressure foot lifting rear lever is connected with one end of a swinging pressure rod, and the other end of the swinging pressure rod is connected with the thread loosening mechanism and the pressure foot lifting mechanism.

Preferably, the thread releasing mechanism comprises a thread releasing connecting rod, a thread releasing top plate and a thread releasing auxiliary nail, one end of the thread releasing connecting rod is hinged to the swing pressing rod, the other end of the thread releasing connecting rod is hinged to one end of the thread releasing top plate, the other end of the thread releasing top plate is arranged opposite to one end of the thread releasing auxiliary nail, and the other end of the thread releasing auxiliary nail is arranged opposite to a thread clamping plate on the thread clamping device.

Preferably, the presser foot lifting mechanism comprises a second slide block hinged to the swing pressure rod, a lifting sleeve sleeved on the presser foot pressure rod in a lifting manner, and an upper stop block fixedly arranged on the presser foot pressure rod, the lifting sleeve is provided with a second sliding groove in sliding fit with the second slide block, and the upper stop block is positioned above the lifting sleeve.

The invention also provides a sewing machine, which comprises the thread trimming and thread loosening presser foot lifting device of the sewing machine.

Compared with the prior art, the invention has the remarkable progress that:

the invention relates to a sewing machine thread trimming loosening presser foot lifting device and a sewing machine comprising the same.A cam structure is driven by a power part to rotate, and corresponding thread trimming mechanism, thread loosening mechanism or presser foot lifting mechanism can be driven to move by the angle matching of a thread trimming driving section of a first driving contour surface and a thread loosening driving section of a second driving contour surface on the cam structure and the angle matching of the presser foot lifting driving section, so that thread trimming action, thread loosening action or presser foot lifting action are executed, namely three functions of thread trimming, thread loosening and presser foot lifting are realized by the driving of the power part.

Drawings

Fig. 1 is a schematic view of the overall structure of a sewing machine according to an embodiment of the present invention.

Fig. 2 is a schematic structural view of a first view angle of a thread trimming, thread loosening and presser foot lifting device of the sewing machine according to the embodiment of the invention.

Fig. 3 is a structural schematic diagram of a second view angle of the thread trimming, thread loosening and presser foot lifting device of the sewing machine according to the embodiment of the invention.

Fig. 4 is a schematic structural view of a third view angle of the thread trimming, thread loosening and presser foot lifting device of the sewing machine according to the embodiment of the invention.

FIG. 5 is a schematic view showing the thread trimming and thread loosening presser foot lifting device of the sewing machine according to the embodiment of the present invention not interfering with the manual presser foot lifting device.

Fig. 6 is a schematic structural view of a first driving contour surface of a cam structure in the thread trimming, loosening and presser foot lifting device of the sewing machine according to the embodiment of the invention.

Fig. 7 is a schematic structural view of a second driving contour surface of a cam structure in the thread trimming, loosening and presser foot lifting device of the sewing machine according to the embodiment of the invention.

FIG. 8 is a schematic diagram of the interval division of one rotation of the power member in the thread trimming and loosening presser foot lifting device of the sewing machine according to the embodiment of the present invention.

Wherein the reference numerals are as follows:

1. bottom plate 2 and shell

3. Power member 301 and rotating shaft

4. Support 5, support back shaft

6. Support supporting plate 7 and first cam

701. First drive contour surface 701a and trimming drive section

701b, a first base circle section 8 and a second cam

801. Second drive profile 801a, Loose wire drive section

801b, a pressure foot lifting driving section 801d and a second base circle section

9. Trimming drive crank 10, first drive pin

11. Trimming drive shaft 12 and trimming transmission crank

13. First slider 14, shear line axle

141. First chute 15 and trimming shaft sleeve

16. Riveting pin 17, trimming crank

18. Trimming auxiliary crank 19 and movable knife

20. Auxiliary moving knife 21, trimming connecting rod

22. Ejector rod 23 and second transmission pin

24. Ejector rod shaft sleeve 25 and ejector block

26. Lift presser foot rear lever 27, swing depression bar

28. Pressure foot lifting connecting rod 29 and driving connecting rod

30. Lifting pressure foot rear lever screw 31 and swinging pressure rod screw

32. Loose wire connecting rod 33 and loose wire top plate

34. Loose wire auxiliary nail 35 and loose wire screw

36. Wire clamping device 37 and second sliding block

38. Lifting sleeve 381 and second sliding chute

39. Upper stopper 40, connecting pin

41. Pressure foot pressure lever 42, pressure lever bush

43. Presser foot 4, lower stop block

46. Lift presser foot cam 47, presser foot spanner

48. Lift presser foot front lever 49, lift presser foot front lever screw pin

50. Presser foot lifting plate

A. Presser foot lifting interval C and thread loosening interval

D. Trimming interval E and residual angle interval

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to limit the present invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

As shown in fig. 1 to 8, an embodiment of the present invention provides a thread trimming and thread loosening presser foot lifting device for a sewing machine. The thread trimming and loosening presser foot lifting device of the sewing machine of the embodiment is arranged in the sewing machine and used for realizing the thread trimming function, the thread loosening function and the presser foot lifting function of the sewing machine.

Referring to fig. 1, the sewing machine has a base plate 1 and a cabinet 2, and the cabinet 2 is fixedly installed on an upper surface of the base plate 1. The thread trimming and loosening presser foot lifting device of the sewing machine of the embodiment is arranged on the bottom plate 1.

Referring to fig. 2, 3 and 4, the thread trimming, thread loosening and presser foot lifting device of the sewing machine of the present embodiment includes a power member 3, a cam structure, a thread trimming driving crank 9, a thread trimming mechanism, a push rod 22, a thread loosening mechanism and a presser foot lifting mechanism.

Referring to fig. 2, the power member 3 is fixedly supported on the bottom plate 1 of the sewing machine through the bracket 4, preferably, the bottom plate 1 may be fixedly provided with a bracket support shaft 5, the bracket support shaft 5 fixedly supports a bracket support plate 6, the bracket 4 is fixedly provided on the bracket support plate 6, and the power member 3 is fixedly provided on the bracket 4, thereby realizing that the power member 3 is fixedly supported on the bottom plate 1 of the sewing machine through the bracket 4. The power member 3 is connected with the cam structure, the power member 3 has a rotating shaft 301, the cam structure is fixedly arranged on the rotating shaft 301 of the power member 3, and the rotating shaft 301 of the power member 3 rotates to drive the cam structure to synchronously rotate, namely, the cam structure is driven by the power member 3 to rotate. The angle of the power part 3 driving the cam structure to rotate is controllable, and preferably, the power part 3 can be a stepping motor or a servo motor, so that the accurate control of the rotation angle of the cam structure can be realized. The cam structure can be directly fixedly mounted on the rotating shaft 301 of the power member 3, and the cam structure can also be fixedly mounted on a transmission shaft externally connected with the rotating shaft 301 of the power member 3.

Referring to fig. 2 and 3, the cam structure has a first drive profile 701 and a second drive profile 801. In the present embodiment, the cam structure may preferably include a first cam 7 and a second cam 8, the first cam 7 is provided with a first driving profile surface 701, and the second cam 8 is provided with a second driving profile surface 801. The first cam 7 and the second cam 8 rotate around the same rotation center, and the first cam 7 and the second cam 8 can be integrally formed into a whole piece or can be coaxially arranged and mutually independent separated pieces. Preferably, the power member 3 may be a dual output shaft motor, both sides of the dual output shaft motor have rotating shafts 301, and the first cam 7 and the second cam 8 are separate members independent of each other and are respectively mounted on the rotating shafts 301 on both sides of the dual output shaft motor. Preferably, the power member 3 is a dual output shaft stepping motor or a dual output shaft servo motor, which can realize precise control of the rotation angles of the first cam 7 and the second cam 8. When the first cam 7 and the second cam 8 are integrally formed as a single piece, a single output shaft motor may be used.

The thread cutting driving crank 9 is connected with the thread cutting mechanism. Referring to fig. 2, the trimming drive crank 9 is provided with a first drive pin 10, and the first drive pin 10 is engaged with a first drive contour 701 of the first cam 7. Referring to fig. 6, the first driving contour 701 has a trimming driving section 701a for driving the trimming driving crank 9 to drive the trimming mechanism to perform the trimming operation, and the first driving contour 701 further has a first base circle section 701b for driving the trimming driving crank 9 to drive the trimming mechanism to perform the idle stroke. The first base circle segment 701b and the trimming driving segment 701a are connected to form a first driving contour surface 701, the first base circle segment 701b is an arc segment concentrically arranged with the rotation center of the first cam 7, and the distance between the trimming driving segment 701a and the rotation center of the first cam 7 gradually increases along the direction away from the first base circle segment 701 b. When the power member 3 drives the cam structure to rotate, the first transmission pin 10 moves along the first driving contour surface 701 on the first cam 7 to be in contact fit with the first base circle segment 701b and the trimming line driving segment 701a along with the rotation of the first cam 7. When the first base circle segment 701b of the first driving contour surface 701 acts on the first transmission pin 10, the position of the first transmission pin 10 is kept unchanged, the trimming driving crank 9 and the trimming mechanism execute an idle stroke, and the trimming mechanism does not act. When the trimming driving section 701a of the first driving contour surface 701 acts on the first transmission pin 10, the trimming driving crank 9 may be driven to swing, and the swinging of the trimming driving crank 9 drives the trimming mechanism to move to perform the trimming operation until the first transmission pin 10 reaches the end of the trimming driving section 701a, thereby completing the trimming operation. After the thread cutting action is finished, the power part 3 drives the cam structure to rotate reversely, so that the first transmission pin 10 moves reversely along the thread cutting driving section 701a and drives the thread cutting driving crank 9 and the thread cutting mechanism to reset. In this embodiment, preferably, the first cam 7 is in a form of a sheave, a first track groove is formed in the first cam 7 of the sheave, an inner side surface of the first track groove close to the rotation center of the first cam 7 forms a first driving contour surface 701 on the first cam 7, and the first transmission pin 10 is inserted into the first track groove and moves along the first track groove to contact and cooperate with the first driving contour surface 701.

In the present embodiment, preferably, referring to fig. 2 and 4, the thread cutting mechanism includes a thread cutting drive shaft 11, the thread cutting drive shaft 11 is rotatably supported on the bed plate 1 of the sewing machine, and the thread cutting drive shaft 11 is parallel to the rotation axis of the power member 3. The thread cutting driving crank 9 is fixedly arranged at one end of a thread cutting driving shaft 11, and the other end of the thread cutting driving shaft 11 is connected with the thread cutting assembly. When the first cam 7 drives the trimming driving crank 9 to swing through the first transmission pin 10, the trimming driving shaft 11 is driven to rotate along with the swinging of the trimming driving crank 9, and the rotation of the trimming driving shaft 11 drives the trimming assembly to move so as to execute trimming.

Further, the thread cutting mechanism may further include a thread cutting driving crank 12, a first slider 13, and a thread cutting spool 14, wherein the thread cutting spool 14 is rotatably supported on the base plate 1, and the thread cutting spool 14 is parallel to the thread cutting driving shaft 11. The thread cutting shaft 14 can be rotatably arranged on the thread cutting shaft sleeve 15 in a penetrating way, and the thread cutting shaft sleeve 15 is fixed on the bottom plate 1. One end of the trimming transmission crank 12 is fixedly arranged on the trimming driving shaft 11, the other end of the trimming transmission crank 12 is hinged with the first sliding block 13, and the hinge axis of the trimming transmission crank 12 and the first sliding block 13 is parallel to the trimming driving shaft 11. Preferably, the thread cutting drive crank 12 and the first slider 13 are hinged by a rivet pin 16, and the axis of the rivet pin 16 is parallel to the thread cutting drive shaft 11. One end of the thread cutting shaft 14 is provided with a first sliding groove 141, the first sliding block 13 is arranged in the first sliding groove 141 and is in sliding fit with the first sliding groove 141, and the other end of the thread cutting shaft 14 is connected with the thread cutting assembly. When the thread cutting driving shaft 11 rotates, the thread cutting shaft 14 can be driven to rotate along with the rotation of the thread cutting driving crank 12 and the sliding fit between the first sliding block 13 and the first sliding groove 141 on the thread cutting shaft 14, and the rotation of the thread cutting shaft 14 drives the thread cutting assembly to move to execute thread cutting action.

The thread trimming component can be a structure capable of realizing thread trimming action in the prior art, and the thread trimming component can be suitable for various structural forms and has the advantage of wide application range. For example, the thread trimming assembly may include a thread trimming crank 17, a thread trimming sub-crank 18, a movable knife 19, and an auxiliary knife 20. In one embodiment, one end of the thread cutting crank 17 and one end of the thread cutting auxiliary crank 18 may both be fixedly disposed at one end of the thread cutting shaft 14 away from the first sliding slot 141, the other end of the thread cutting crank 17 is hinged to the movable knife 19 through the thread cutting connecting rod 21, the other end of the thread cutting auxiliary crank 18 is hinged to the auxiliary knife 20, and when the thread cutting shaft 14 rotates, the movable knife 19 and the auxiliary knife 20 may be driven to move relatively by the transmission of the thread cutting crank 17 and the thread cutting auxiliary crank 18, so as to perform a thread cutting operation. In another embodiment, the trimming transmission crank 12, the first slider 13 and the trimming shaft 14 may be omitted, one end of the trimming crank 17 and one end of the trimming auxiliary crank 18 are both fixed on the trimming driving shaft 11, the other end of the trimming crank 17 is hinged to the movable knife 19 through the trimming connecting rod 21, the other end of the trimming auxiliary crank 18 is hinged to the auxiliary knife 20, and when the trimming driving shaft 11 rotates, the movable knife 19 and the auxiliary knife 20 are driven to move relatively by the transmission of the trimming crank 17 and the trimming auxiliary crank 18 to perform the trimming operation. Of course, the structure of the thread cutting assembly is not limited to this double-action knife structure, and a single-action knife structure may be employed.

Referring to fig. 3, one end of the top bar 22 is provided with a second transmission pin 23, and the other end of the top bar 22 is connected with the thread releasing mechanism and the presser foot lifting mechanism. The ejector 22 can be movably arranged on the ejector shaft sleeve 24 up and down, and the ejector shaft sleeve 24 is fixedly arranged on the bottom plate 1. The second driving pin 23 is provided at the lower end of the carrier rod 22, and preferably, an ejector block 25 is provided at the lower end of the carrier rod 22, and the second driving pin 23 is provided on the ejector block 25. The second driving pin 23 is engaged with the second driving contour surface 801 of the second cam 8, and when the second driving contour surface 801 acts on the second driving pin 23, the lift motion of the carrier rod 22 can be driven. Referring to fig. 7, the second driving contour 801 includes a thread releasing driving section 801a for driving the push rod 22 to drive the thread releasing mechanism to release thread and a presser foot lifting driving section 801b for driving the push rod 22 to drive the presser foot lifting mechanism to lift the presser foot, and the second driving contour 801 further includes a second base circle section 801d for driving the push rod 22 to drive both the thread releasing mechanism and the presser foot lifting mechanism to perform idle stroke. The second base circle section 801d, the thread loosening driving section 801a, and the presser foot lifting driving section 801b are sequentially connected to form a second driving contour surface 801, the second base circle section 801d is an arc section concentrically arranged with the rotation center of the second cam 8, and the distances between the thread loosening driving section 801a, the presser foot lifting driving section 801b, and the rotation center of the second cam 8 gradually decrease in sequence in a direction away from the second base circle section 801 d. When the power member 3 drives the cam structure to rotate, the second transmission pin 23 moves along the second driving contour surface 801 on the second cam 8 to be in contact engagement with the second base circle section 801d, the thread releasing driving section 801a and the presser foot lifting driving section 801 b. When the second base circle section 801d of the second driving contour surface 801 acts on the second transmission pin 23, the position of the second transmission pin 23 is kept unchanged, the push rod 22 performs an idle stroke, and at this time, both the thread slacking mechanism and the presser foot lifting mechanism perform an idle stroke without action. When the thread releasing driving section 801a of the second driving contour surface 801 acts on the second transmission pin 23, the push rod 22 can be driven to descend, and the thread releasing mechanism is driven to move by the descending of the push rod 22 to perform thread releasing action. When the presser foot lifting driving section 801b of the second driving contour surface 801 acts on the second transmission pin 23, the push rod 22 can be driven to ascend, and the presser foot lifting mechanism is driven to move by the ascending of the push rod 22 to perform the presser foot lifting action. In this embodiment, preferably, the second cam 8 is in the form of a grooved wheel, a second track groove is formed in the grooved wheel type second cam 8, an inner side surface of the second track groove close to the rotation center of the second cam 8 forms a second driving contour surface 801 on the second cam 8, and the second transmission pin 23 is inserted into the second track groove and moves along the second track groove to contact and cooperate with the second driving contour surface 801.

In the present embodiment, preferably, referring to fig. 2 and 3, the push rod 22 is connected to one end of a rear lever 26 for lifting the presser foot, the other end of the rear lever 26 for lifting the presser foot is connected to one end of a swing pressure lever 27, and the other end of the swing pressure lever 27 is connected to the thread slacking mechanism and the presser foot lifting mechanism. When the top rod 22 is lifted, the thread loosening mechanism and the presser foot lifting mechanism can be driven to move through the transmission of the presser foot lifting rear lever 26 and the swinging pressure rod 27, and the thread loosening action and the presser foot lifting action are realized. Preferably, a presser foot lifting connecting rod 28 may be disposed between the top rod 22 and the presser foot lifting rear lever 26, and two ends of the presser foot lifting connecting rod 28 are respectively hinged to the top rod 22 and the presser foot lifting rear lever 26. A driving connecting rod 29 can be arranged between the pressure foot lifting rear lever 26 and the swinging pressure rod 27, and two ends of the driving connecting rod 29 are respectively hinged with the pressure foot lifting rear lever 26 and the swinging pressure rod 27. Specifically, in the present embodiment, the upper end of the top rod 22 is hinged to one end of a presser foot lifting connecting rod 28, the other end of the presser foot lifting connecting rod 28 is hinged to one end of a presser foot lifting rear lever 26, the middle part of the presser foot lifting rear lever 26 is mounted on the housing 2 of the sewing machine through a presser foot lifting rear lever screw 30, the presser foot lifting rear lever 26 can rotate around the presser foot lifting rear lever screw 30, the other end of the presser foot lifting rear lever 26 is hinged to one end of a driving connecting rod 29, the other end of the driving connecting rod 29 is hinged to one end of a swing pressure lever 27, the middle part of the swing pressure lever 27 is mounted on the housing 2 of the sewing machine through a swing pressure lever screw 31, the swing pressure lever 27 can rotate around the swing pressure lever screw 31, and the other end of the swing pressure lever 27 is connected to the thread releasing mechanism and the presser foot lifting mechanism. When the push rod 22 is lifted, the pressure foot lifting connecting rod 28 drives the pressure foot lifting rear lever 26 to rotate around the pressure foot lifting rear lever screw 30, the pressure foot lifting rear lever 26 rotates to drive the driving connecting rod 29 to move, the swinging pressure rod 27 is driven to rotate around the swinging pressure rod screw 31, and the rotation of the swinging pressure rod 27 drives the thread loosening mechanism and the pressure foot lifting mechanism to move.

In this embodiment, preferably, referring to fig. 2 and 4, the thread releasing mechanism includes a thread releasing link 32, a thread releasing top plate 33, and a thread releasing auxiliary nail 34, one end of the thread releasing link 32 is hinged to the swing pressing rod 27, the other end of the thread releasing link 32 is hinged to one end of the thread releasing top plate 33, the middle of the thread releasing top plate 33 is mounted on the machine case 2 of the sewing machine through a thread releasing screw 35, the thread releasing top plate 33 can rotate around the thread releasing screw 35, the other end of the thread releasing top plate 33 is arranged opposite to one end of the thread releasing auxiliary nail 34, and the other end of the thread releasing auxiliary nail 34 is arranged opposite to a thread clamping plate on the thread clamping device 36. The thread releasing top plate 33 has an action surface facing the end surface of the thread releasing auxiliary nail 34 and inclined with respect to the end surface of the thread releasing auxiliary nail 34, and the action surface can be brought into contact with or separated from the end surface of the thread releasing auxiliary nail 34 by the rotation of the thread releasing top plate 33. When the swing pressure lever 27 rotates, the thread releasing connecting rod 32 can be driven to drive the thread releasing top plate 33 to rotate around the thread releasing screw 35, so that the thread releasing top plate 33 pushes the thread releasing auxiliary nail 34 to move, and the motion of the thread releasing auxiliary nail 34 pushes the thread clamping plate on the thread clamping device 36 to move, thereby realizing the thread releasing action. The tight connection between the thread loosening time and the thread shearing time can be realized by controlling the rotating angle of the cam structure through the power part 3, and the response speed is increased.

In this embodiment, preferably, referring to fig. 2, the presser foot lifting mechanism includes a second slider 37, a lifting sleeve 38, and an upper stopper 39. The second slider 37 is hinged to the swing compression bar 27, and the hinge axis of the second slider 37 and the swing compression bar 27 is parallel to the axis of the swing compression bar screw 31. Preferably, the second slider 37 and the swing strut 27 can be hinged by a connecting pin 40, the axis of the connecting pin 40 is parallel to the axis of the swing strut screw 31. The lifting sleeve 38 is sleeved on the presser foot pressing rod 41 in a lifting manner, the presser foot pressing rod 41 can be movably arranged on the pressing rod bushing 42 in a penetrating manner up and down, the pressing rod bushing 42 is fixedly arranged on the shell 2 of the sewing machine, and the lower end of the presser foot pressing rod 41 is connected with the presser foot 43. The lifting sleeve 38 is provided with a second sliding groove 381, and the second sliding block 37 is arranged in the second sliding groove 381 and is in sliding fit with the second sliding groove 381. The upper stop block 39 is fixedly arranged at the upper end of the presser foot pressing rod 41, and the upper stop block 39 is positioned above the lifting sleeve 38. When the swing pressure lever 27 rotates and rotates upwards around the swing pressure lever screw 31, the lifting sleeve 38 is driven to move upwards along the pressure foot pressure lever 41 through the transmission of the connecting pin 40 and the sliding fit of the second slide block 37 and the second slide groove 381 on the lifting sleeve 38, and the lifting sleeve 38 and the upper stop block 39 push the upper stop block 39 to drive the pressure foot pressure lever 41 to move upwards together when contacting, so that the pressure foot 43 is driven to ascend, and the pressure foot lifting action is realized. Conversely, when the swing pressure lever 27 rotates and rotates downward around the swing pressure lever screw 31, the presser foot 43 is driven to descend, and the height of the presser foot is reduced. The accurate control of the lifting height of the presser foot can be realized by controlling the rotating angle of the cam structure through the power part 3.

The presser foot lifting mechanism of the embodiment does not interfere the installation of the existing manual presser foot lifting device, and can meet the requirements of different users at the same time. Referring to fig. 5, a lower stop 44 may be further disposed on the presser foot pressing rod 41, the lower stop 44 is fixedly disposed on the presser foot pressing rod 41, and the lower stop 44 is disposed below the lifting sleeve 38, a conventional manual presser foot lifting device generally includes a presser foot lifting cam 46 disposed on the sewing machine housing 2, a presser foot wrench 47 is disposed on the presser foot lifting cam 46, the presser foot wrench 47 is exposed out of the sewing machine housing 2, the presser foot lifting cam 46 is rotatable by manually rotating the presser foot wrench 47, a presser foot lifting front lever 48 is mounted on the sewing machine housing 2 through a presser foot lifting front lever threaded pin 49, the presser foot lifting front lever 48 is rotatable around a presser foot lifting front lever threaded pin 49, one end of the presser foot lifting front lever 48 is matched with the presser foot lifting cam 46, the other end of the presser foot lifting front lever 48 is hinged to an upper end of a presser foot lifting plate 50, and a lower end of the presser foot lifting plate 50 is disposed below the lower stop 44 and opposite to the lower stop 44. When the presser foot lifting spanner 47 is rotated to rotate the presser foot lifting cam 46, the presser foot lifting cam 46 acts on the presser foot lifting front lever 48, the presser foot lifting front lever 48 is rotated, so that the presser foot lifting plate 50 is driven to lift, when the presser foot lifting plate 50 lifts, the presser foot lifting plate 50 is contacted with the lower stop block 44 and pushes the lower stop block 44 to drive the presser foot pressing rod 41 to move upwards together, and the presser foot 43 is driven to lift, so that the presser foot lifting action is realized. Conversely, when the presser foot lifting plate 50 is lowered, the presser foot 43 is driven to be lowered, thereby realizing the lowering of the height of the presser foot. The components constituting the manual presser foot lifting device (presser foot lifting cam 46, presser foot wrench 47, presser foot lifting front lever 48, presser foot lifting front lever screw pin 49, and presser foot lifting plate 50) are mounted without interfering with the components of the presser foot lifting mechanism in the present embodiment. Because the lifting sleeve 38 is sleeved on the presser foot pressing rod 41 in a lifting manner, in the process of manually lifting the presser foot by the manual presser foot lifting device, the presser foot pressing rod 41 does not drive the lifting sleeve 38 to move along with the lifting movement when the lifting movement is generated, and interference influence is not generated on the working position of the presser foot lifting device for thread cutting and thread loosening of the sewing machine of the embodiment.

According to the thread trimming and thread loosening presser foot lifting device of the sewing machine, the cam structure is driven to rotate by the power part 3, the corresponding thread trimming mechanism, thread loosening mechanism or presser foot lifting mechanism can be driven to move through the angle matching of the thread trimming driving section 701a of the first driving contour surface 701 and the thread loosening driving section 801a and the presser foot lifting driving section 801b of the second driving contour surface 801 on the cam structure, thread trimming action, thread loosening action or presser foot lifting action are executed, namely three functions of thread trimming, thread loosening and presser foot lifting are realized through the driving of the power part 3, the structure can be greatly simplified, the structure is simple and compact, the transmission efficiency is high, and the working precision and the stability are good.

In this embodiment, the power member 3 may be connected to a controller (not shown in the figure), and the controller controls the power member 3 to start or stop rotating according to the operation requirement of the sewing machine, and controls the rotating direction and the rotating angle of the power member 3, so as to control the matching state between the first driving contour surface 701 on the cam structure and the first driving pin 10 on the trimming driving crank 9, and the matching state between the second driving contour surface 801 and the second driving pin 23 on the top bar 22, and realize the precise control of the trimming, the thread loosening and the presser foot lifting. The controller can be a main controller of the existing sewing machine, such as a PLC controller or a singlechip. Preferably, the controller can also be connected with an encoder, the encoder feeds back the speed and the rotation angle position of the power part 3 to the controller, and the controller controls the rotation angle and the rotation speed of the power part 3 according to the feedback information of the encoder to form closed-loop control, so that the motion stability and the accuracy are ensured.

Referring to fig. 8, in the present embodiment, the rotating shaft 301 of the power member 3 rotates a circle to be divided into at least three working intervals, which include a presser foot lifting interval a, a thread loosening interval C, and a thread trimming interval D sequentially arranged along the circumferential direction of the rotating shaft 301, the presser foot lifting interval a, the thread loosening interval C, and the thread trimming interval D may form a whole circle of the rotating shaft 301 of the power member 3, and may also leave a margin in the whole circle, that is, the rotating shaft 301 of the power member 3 rotates a circle to be divided into a remaining angle interval E, so that the rotating shaft 301 of the power member 3 drives other executing mechanisms of the sewing machine to execute corresponding actions when rotating in the remaining angle interval E. The remaining angle section E may be provided between any two adjacent sections among the presser foot lifting section a, the thread loosening section C, and the thread trimming section D, and preferably, the remaining angle section E is provided between the presser foot lifting section a and the thread trimming section D. The directions in which the three working intervals, i.e., the presser foot lifting interval a, the thread loosening interval C, and the thread trimming interval D, are arranged along the circumferential direction of the rotating shaft 301 are not limited, and may be arranged sequentially along the counterclockwise direction in the circumferential direction of the rotating shaft 301 (as shown in fig. 8), or may be arranged sequentially along the clockwise direction in the circumferential direction of the rotating shaft 301.

Corresponding to the working interval of the rotating shaft 301 of the power member 3, referring to fig. 6, the trimming driving section 701a of the first driving contour surface 701 of the first cam 7 corresponds to the trimming interval D, and the first base circle section 701b of the first driving contour surface 701 of the first cam 7 corresponds to the presser foot lifting interval a and the thread loosening interval C. That is, when the rotating shaft 301 of the power member 3 is located within the trimming section D, the trimming drive section 701a of the first drive contour surface 701 of the first cam 7 acts on the first transmission pin 10 of the trimming drive crank 9; when the rotating shaft 301 of the power member 3 is located in the presser foot lifting interval a and the thread releasing interval C, the first base circle segment 701b of the first driving contour surface 701 of the first cam 7 acts on the first transmission pin 10 of the trimming driving crank 9. Referring to fig. 7, the pressure and foot lifting driving section 801b of the second driving contour 801 on the second cam 8 corresponds to the pressure and foot lifting interval a, the loose wire driving section 801a of the second driving contour 801 on the second cam 8 corresponds to the loose wire interval C, and the second base circle section 801D of the second driving contour 801 on the second cam 8 corresponds to the trimming interval D. That is, when the rotating shaft 301 of the power member 3 is located within the presser foot lifting interval a, the presser foot lifting driving section 801b of the second driving contour surface 801 on the second cam 8 acts on the second transmission pin 23 on the push rod 22; when the rotating shaft 301 of the power part 3 is located in the slack line interval C, the slack line driving section 801a of the second driving contour surface 801 on the second cam 8 acts on the second transmission pin 23 on the push rod 22; when the rotational axis 301 of the power element 3 is located in the trimming interval D, the second base circle segment 801D of the second driving contour 801 on the second cam 8 acts on the second transmission pin 23 on the carrier rod 22. Therefore, the angle matching relationship between the trimming driving section 701a of the first driving contour surface 701 and the thread loosening driving section 801a and the presser foot lifting driving section 801b of the second driving contour surface 801 in the cam structure satisfies the following conditions.

When the rotating shaft 301 of the power member 3 is located in the presser foot lifting interval a, the second transmission pin 23 on the push rod 22 is located in the presser foot lifting driving section 801b of the second driving contour surface 801 on the second cam 8, and the push rod 22 can be driven to ascend by the presser foot lifting driving section 801b to drive the presser foot lifting mechanism to execute the presser foot lifting action, so as to obtain the required presser foot height. In the process of lifting the presser foot, the lifting sleeve 38 is kept in contact with the upper stop block 39 and cannot generate vertical displacement relative to the presser foot pressing rod 41; the thread releasing top plate 33 rotates along with the swing pressure rod 27 around the swing pressure rod screw 31 upwards and leaves the thread releasing auxiliary nail 34, so that thread releasing action is not generated; and the first transmission pin 10 on the trimming driving crank 9 is positioned on the first base circle segment 701b of the first driving contour surface 701 on the first cam 7, the trimming driving crank 9 executes an idle stroke, and the trimming mechanism does not act.

When the rotating shaft 301 of the power member 3 is located in the thread releasing interval C, the second transmission pin 23 on the push rod 22 is located in the thread releasing driving section 801a of the second driving contour surface 801 on the second cam 8, and the push rod 22 can be driven to descend by the thread releasing driving section 801a to drive the thread releasing mechanism to perform thread releasing action. In the process of loosening the thread, the lifting sleeve 38 rotates downwards around the swing pressure rod screw 31 along with the swing pressure rod 27 and moves downwards relative to the presser foot pressure rod 41, so that the presser foot lifting action is not generated; and the first transmission pin 10 on the trimming driving crank 9 is positioned on the first base circle segment 701b of the first driving contour surface 701 on the first cam 7, the trimming driving crank 9 executes an idle stroke, and the trimming mechanism does not act.

When the rotating shaft 301 of the power member 3 is located within the trimming interval D, the first transmission pin 10 on the trimming driving crank 9 is located on the trimming driving section 701a of the first driving contour surface 701 on the first cam 7, and the trimming driving section 701a can drive the trimming driving crank 9 to swing to drive the trimming mechanism to perform trimming. At this time, the second transmission pin 23 on the push rod 22 is located at the second base circle section 801d of the second driving contour surface 801 on the second cam 8, the push rod 22 performs an idle stroke, and neither the thread slacking mechanism nor the presser foot lifting mechanism operates.

Therefore, the purposes that the thread cutting action, the thread loosening action and the presser foot lifting action do not interfere with each other are achieved.

Based on above-mentioned sewing machine trimming pine thread lifts presser foot device, this embodiment still provides a sewing machine, and the sewing machine of this embodiment includes the above-mentioned sewing machine trimming pine thread of this embodiment and lifts presser foot device.

Based on the above device for lifting the presser foot by cutting thread and loosing thread of the sewing machine, the present embodiment further provides a method for lifting the presser foot by cutting thread and loosing thread of the sewing machine, that is, the working method of the device for lifting the presser foot by cutting thread and loosing thread of the sewing machine of the present embodiment is adopted.

The method for lifting the presser foot by trimming and slacking threads of the sewing machine of the embodiment is that a power part 3 drives a cam structure to rotate, a thread trimming mechanism is driven to execute thread trimming action by a trimming drive section 701a of a first drive contour surface 701 on the cam structure, the thread slacking mechanism is driven to execute thread slacking action by a slacking drive section 801a of a second drive contour surface 801 on the cam structure, a presser foot lifting mechanism is driven to execute presser foot lifting action by a presser foot lifting drive section 801b of the second drive contour surface 801 on the cam structure, and when the current execution action is one of the thread trimming action, the thread slacking action and the presser foot lifting action, the other two actions do not occur. The details are as follows.

When the sewing machine sews normally, the controller controls the rotating shaft 301 of the power part 3 to be located at the initial position between the presser foot lifting interval a and the thread releasing interval C, so that the cam structure is located at the initial position, the second transmission pin 23 on the ejector rod 22 is located at the boundary of the presser foot lifting driving section 801b and the thread releasing driving section 801a of the second driving profile surface 801 on the second cam 8, at this time, the height of the presser foot is the height required during normal sewing, and the first transmission pin 10 on the thread cutting driving crank 9 is located at the first base circle section 701b of the first driving profile surface 701 on the first cam 7.

In the working process of the sewing machine, when the presser foot needs to be lifted, the controller can control the rotating shaft 301 of the power part 3 to rotate from the initial position to the presser foot lifting interval A and enter the presser foot lifting interval A according to a presser foot lifting instruction, so that the second transmission pin 23 on the ejector rod 22 moves along the second driving contour surface 801 on the second cam 8 and enters the presser foot lifting driving section 801b, the presser foot lifting driving section 801b drives the ejector rod 22 to ascend to drive the presser foot lifting mechanism to execute the presser foot lifting action, until the presser foot is lifted to the required presser foot height, the controller controls the rotating shaft 301 of the power part 3 to stop rotating, the presser foot lifting action is completed, and then the related operation at the presser foot height can be manually performed. In the process of lifting the presser foot, the lifting sleeve 38 keeps contact with the upper stop block 39 and cannot generate vertical displacement relative to the presser foot pressing rod 41; the thread releasing top plate 33 cannot rotate to contact and push the thread releasing auxiliary nail 34, so that the thread releasing mechanism does not generate thread releasing action; the first driving pin 10 of the trimming driving crank 9 moves along the first base circle segment 701b of the first driving contour surface 701 of the first cam 7 to perform an idle stroke, and the trimming mechanism does not operate. When the presser foot lifting action is finished and the operation is finished, the controller can control the rotating shaft 301 of the power part 3 to reversely rotate from the presser foot lifting interval A to the initial position and reset the presser foot lifting mechanism to the initial position, so that the presser foot is lowered to the initial position.

In the working process of the sewing machine, when thread loosening is needed, feeding can be stopped firstly, then the controller controls the rotating shaft 301 of the power part 3 to rotate from the initial position to the thread loosening interval C and enter the thread loosening interval C according to a thread loosening instruction, so that the second driving pin 23 on the ejector rod 22 moves along the second driving contour surface 801 on the second cam 8 and enters the thread loosening driving section 801a, and the thread loosening driving section 801a drives the ejector rod 22 to descend to drive the thread loosening mechanism to perform thread loosening. In the process of loosening the thread, the lifting sleeve 38 rotates downwards around the swing pressure rod screw 31 along with the swing pressure rod 27 and moves downwards relative to the presser foot pressure rod 41, and the presser foot lifting mechanism does not generate the presser foot lifting action; the first driving pin 10 of the trimming driving crank 9 moves along the first base circle segment 701b of the first driving contour surface 701 of the first cam 7 to perform an idle stroke, and the trimming mechanism does not operate. After the thread releasing action is finished, if the thread cutting action is not needed, the rotating shaft 301 of the power part 3 can be controlled by the controller to reversely rotate from the thread releasing interval C to the initial position and reset to the initial position, so that the thread releasing mechanism is reset. After the thread loosening is finished, if the thread cutting action is required, the controller can control the rotating shaft 301 of the power part 3 to continuously rotate from the thread loosening interval C to the thread cutting interval D and enter the thread cutting interval D so as to perform the thread cutting action.

In the working process of the sewing machine, when thread cutting is needed, feeding can be stopped firstly, then the controller controls the rotating shaft 301 of the power part 3 to rotate from the initial position to the thread loosening interval C according to a thread cutting instruction, the thread loosening interval C is passed by the rotating shaft, the thread loosening interval D is entered, the thread loosening action is executed in the thread loosening interval C, and then the thread cutting action is executed in the thread cutting interval D. Specifically, after the rotating shaft 301 of the power member 3 rotates from the initial position to the thread releasing interval C and enters the thread releasing interval C, the second transmission pin 23 on the push rod 22 moves along the second driving contour surface 801 on the second cam 8 and enters the thread releasing driving section 801a, and the push rod 22 is driven by the thread releasing driving section 801a to descend, so as to drive the thread releasing mechanism to perform a thread releasing action. After the thread loosening action is completed, the controller controls the rotating shaft 301 of the power part 3 to continue to rotate from the thread loosening interval C to the thread cutting interval D and enter the thread cutting interval D, so that the first transmission pin 10 on the thread cutting driving crank 9 enters the thread cutting driving section 701a from the first base circle section 701b of the first driving contour surface 701 on the first cam 7, the thread cutting driving section 701a drives the thread cutting driving crank 9 to swing to drive the thread cutting mechanism to perform the thread cutting action, at this time, the second transmission pin 23 on the ejector rod 22 enters the second base circle section 801D from the thread loosening driving section 801a of the second driving contour surface 801 on the second cam 8, the ejector rod 22 performs an idle stroke, and the thread loosening mechanism and the presser foot lifting mechanism do not act. After the thread trimming operation is finished, the controller can control the rotating shaft 301 of the power part 3 to reversely rotate from the thread trimming interval D to the initial position and reset to the initial position, so that the thread trimming mechanism and the thread releasing mechanism reset.

Therefore, according to the method for lifting the presser foot by trimming and loosening the sewing machine in the embodiment, the cam structure is driven to rotate by the power part 3, the corresponding trimming mechanism, the corresponding loosening mechanism or the corresponding presser foot lifting mechanism are respectively driven to move when needed through the angle matching of the trimming driving section 701a of the first driving contour surface 701 and the loosening driving section 801a and the presser foot lifting driving section 801b of the second driving contour surface 801 on the cam structure, the trimming action, the loosening action or the presser foot lifting action is executed, namely three functions of trimming, loosening and presser foot lifting are realized by the driving of the power part 3, the working precision and the stability are good, the height of the presser foot can be freely adjusted according to different requirements, the efficiency is improved, the tight connection between the loosening and the trimming time is realized, and the response speed is increased.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. The utility model provides a sewing machine trimming pine thread lifts presser foot device which characterized in that includes:

a power member (3);

a cam structure driven by the power member (3) to rotate, the cam structure having a first drive profile surface (701) and a second drive profile surface (801);

the trimming driving crank (9) is connected with the trimming mechanism, a first transmission pin (10) is arranged on the trimming driving crank (9), the first transmission pin (10) is matched with the first driving contour surface (701), and the first driving contour surface (701) is provided with a trimming driving section (701a) which drives the trimming mechanism to execute trimming action; and

the thread take-up mechanism comprises a push rod (22), wherein one end of the push rod (22) is provided with a second transmission pin (23), the other end of the push rod is connected with a thread take-up mechanism and a presser foot lifting mechanism, the second transmission pin (23) is matched with a second driving contour surface (801), and the second driving contour surface (801) is provided with a thread take-up driving section (801a) for driving the thread take-up mechanism to perform thread take-up action and a presser foot lifting driving section (801b) for driving the presser foot lifting mechanism to perform presser foot lifting action;

the cam structure is driven to rotate by one power piece (3), the trimming mechanism is driven to perform trimming through the trimming driving section (701a) of the first driving contour surface (701) on the cam structure, the loosening mechanism is driven to perform loosening through the loosening driving section (801a) of the second driving contour surface (801) on the cam structure, the presser foot lifting mechanism is driven to perform presser foot lifting through the presser foot lifting driving section (801b) of the second driving contour surface (801) on the cam structure, and when the current performing action is one of trimming, loosening and presser foot lifting, the other two actions do not occur.

2. The sewing machine trimming, thread loosening and presser foot lifting device according to claim 1, wherein the cam structure comprises a first cam (7) and a second cam (8), the first cam (7) being provided with the first driving profile surface (701), the second cam (8) being provided with the second driving profile surface (801).

3. The thread trimming and thread loosening presser foot lifting device of a sewing machine according to claim 2, wherein the power member (3) is a dual output shaft motor, and the first cam (7) and the second cam (8) are respectively mounted on the rotating shafts (301) at both sides of the dual output shaft motor.

4. The sewing machine thread trimming and thread loosening presser foot lifting device according to claim 1, wherein the thread trimming mechanism comprises a thread trimming drive shaft (11), the thread trimming drive shaft (11) is rotatably supported on a base plate (1) of the sewing machine, the thread trimming drive crank (9) is fixedly arranged on the thread trimming drive shaft (11), and the thread trimming drive shaft (11) is connected with a thread trimming assembly.

5. The thread trimming and thread loosening presser foot lifting device of the sewing machine according to claim 4, wherein the thread trimming mechanism further comprises a thread trimming transmission crank (12) fixedly arranged on the thread trimming driving shaft (11), a first sliding block (13) hinged with the thread trimming transmission crank (12), and a thread trimming shaft (14) rotatably supported on the base plate (1) and parallel to the thread trimming driving shaft (11), one end of the thread trimming shaft (14) is provided with a first sliding groove (141) in sliding fit with the first sliding block (13), and the other end of the thread trimming shaft (14) is connected with the thread trimming assembly.

6. The thread trimming and thread loosening presser foot lifting device of sewing machine according to claim 1, wherein said ejector rod (22) is connected to one end of a presser foot lifting rear lever (26), the other end of said presser foot lifting rear lever (26) is connected to one end of a swing pressing rod (27), and the other end of said swing pressing rod (27) is connected to said thread loosening mechanism and presser foot lifting mechanism.

7. The thread trimming and thread releasing presser foot lifting device of the sewing machine according to claim 6, wherein the thread releasing mechanism comprises a thread releasing link (32), a thread releasing top plate (33) and a thread releasing auxiliary nail (34), one end of the thread releasing link (32) is hinged with the swing pressure rod (27), the other end of the thread releasing link is hinged with one end of the thread releasing top plate (33), the other end of the thread releasing top plate (33) is arranged opposite to one end of the thread releasing auxiliary nail (34), and the other end of the thread releasing auxiliary nail (34) is arranged opposite to a thread clamping plate on the thread clamping device (36).

8. The thread trimming and thread loosening presser foot lifting device of the sewing machine according to claim 6, wherein the presser foot lifting mechanism comprises a second slide block (37) hinged to the swing pressure lever (27), a lifting sleeve (38) sleeved on a presser foot pressure lever (41) in a lifting manner, and an upper stop block (39) fixedly arranged on the presser foot pressure lever (41), a second sliding groove (381) in sliding fit with the second slide block (37) is arranged on the lifting sleeve (38), and the upper stop block (39) is positioned above the lifting sleeve (38).

9. A sewing machine characterized by comprising the thread trimming and thread loosening presser foot lifting device of the sewing machine according to any one of claims 1 to 8.