A presser foot device for a sewing machine

Abstract

The technical scheme belongs to the technical field of sewing machines, and specifically relates to a middle presser foot device of a sewing machine, comprising a driving motor having an output shaft; a first-stage transmission assembly, comprising a driving crank mounted on the output shaft; a second-stage transmission assembly, comprising a lever and a transmission connecting rod, wherein the rear end of the lever is hinged on a sewing machine housing, the front end of the lever is hinged to the upper end of the transmission connecting rod, and the lower end of the transmission connecting rod is hinged to a middle presser foot rod; and a middle presser foot mechanism, comprising a middle presser foot rod and a middle presser foot, wherein the middle presser foot rod is vertically mounted on the sewing machine housing, and the middle presser foot is mounted at the lower part of the middle presser foot rod; a receiving mechanism is arranged between the first-stage transmission assembly and the second-stage transmission assembly, and comprises: a sliding groove, which is arranged in the middle part of the lever; and a sliding member, which is rotatably mounted on the swinging end of the driving crank and movably placed in the sliding groove; wherein the driving crank drives the lever to rotate around a hinge point through the sliding member to realize the lifting and lowering of the middle presser foot mechanism.

Description

Technical Field

[0001] The technical solution relates to the technical field of sewing machines, and in particular to a presser foot device in a sewing machine. Background Art

[0002] When sewing with a sewing machine, the thread hooking mechanism of the sewing machine cannot hook the thread loop of the needle and thread, resulting in no complete continuous stitches being formed in the seam. This discontinuous stitch is called skipped stitch. In order to realize the anti-skipped stitch function of the sewing machine, the current common practice is to add a middle presser foot mechanism to the sewing machine. The middle presser foot mechanism moves up and down with the needle to improve the stability of sewing.

[0003] Chinese patent CN220789021U discloses a sewing machine and a presser foot height adjustment device thereof. The transmission mode of the presser foot mechanism of the sewing machine is to directly connect the first connecting rod through the drive rod arranged at the output end of the drive motor for transmission. The drive motor directly drives the presser foot mechanism. This "straight up and straight down" transmission mode will increase the operating burden of the drive motor and require a larger output torque of the drive motor. In this way, the power and volume of the drive motor are inevitably larger, and the heat generation phenomenon is serious. Therefore, a more labor-saving and stable driving mode is urgently needed. Summary of the invention

[0004] The purpose of this technical solution is to provide a middle presser foot device for a sewing machine, which realizes the lifting and lowering control of the middle presser foot mechanism by the driving motor through the cooperation of the first-stage transmission assembly and the second-stage transmission assembly, thereby solving the laborious problem caused by the driving motor of the original sewing machine directly driving the middle presser foot mechanism.

[0005] The purpose of this technical solution is achieved in this way:

[0006] A middle presser foot device for a sewing machine comprises: a driving motor, which is used to lift or lower a middle presser foot, and the driving motor has an output shaft; a first-stage transmission assembly, which comprises a driving crank, and the driving crank is mounted on the output shaft; a second-stage transmission assembly, which comprises a lever and a transmission connecting rod, the rear end of the lever is hinged on a sewing machine housing, the front end of the lever is hinged to the upper end of the transmission connecting rod, and the lower end of the transmission connecting rod is hinged to a middle presser foot rod; and a middle presser foot mechanism, which comprises a middle presser foot rod and a middle presser foot, the middle presser foot rod is vertically mounted on the sewing machine housing, and the middle presser foot is mounted on the lower part of the middle presser foot rod; a receiving mechanism is arranged between the first-stage transmission assembly and the second-stage transmission assembly, and the receiving mechanism comprises: a sliding groove, which is arranged in the middle part of the lever; and a sliding member, which is rotatably mounted on the swinging end of the driving crank and movably placed in the sliding groove; wherein the driving crank drives the lever to rotate around a hinge point through the sliding member to realize the lifting and lowering of the middle presser foot mechanism.

[0007] Preferably, the driving crank sleeve is arranged outside the output shaft, and a plug-in hole is opened at the front end of the driving crank; a plug-in rod is arranged in the plug-in hole; the sliding piece is sleeved at the front end of the plug-in rod; when the front end of the driving crank makes a circular motion, the sliding piece slides in the sliding groove.

[0008] Preferably, a presser foot guide is provided at the lower end of the transmission connecting rod, and the presser foot guide has a second plug-in hole; the upper end of the middle presser foot rod is arranged in the second plug-in hole.

[0009] Preferably, the front end of the presser foot guide frame has a guiding portion, the inner side of the sewing machine housing is provided with a vertical sliding groove, and the guiding portion is movably placed in the sliding groove of the sewing machine housing.

[0010] Preferably, the driving motor is arranged inside the sewing machine housing and close to the rear side of the sewing machine housing; an articulated seat is arranged on the inner wall of the rear side of the sewing machine housing, and the rear end of the lever is hinged on the articulated seat.

[0011] Preferably, the sliding groove is a rectangular groove and is arranged along the length direction of the lever; the sliding member is a square member, and the upper and lower surfaces of the sliding member are in contact with the upper and lower surfaces of the sliding groove; the length of the sliding groove is greater than the length of the sliding member.

[0012] Preferably, when the driving crank swings to a horizontal state, the lever is in a horizontal state, and the transmission connecting rod is in a vertical state.

[0013] Preferably, the length of the lever is greater than or equal to the length of the transmission connecting rod.

[0014] Compared with the prior art, the technical solution has the following outstanding and beneficial technical effects:

[0015] 1. The technical solution is designed with a two-stage transmission assembly. The driving motor cooperates with the first-stage transmission assembly and the second-stage transmission assembly to realize the lifting and lowering of the middle presser foot mechanism, and the receiving mechanism arranged between the first-stage transmission assembly and the second-stage transmission assembly can rotate the lever. The rotation of the lever drives the transmission connecting rod to move at the same time. This transmission method has the effect of saving effort and being stable, so it reduces the burden on the driving motor and extends the service life of the driving motor.

[0016] 2. The receiving mechanism designed in this technical solution can realize that when the driving crank swings to a large extent, the lever and the transmission connecting rod only swing to a small extent, which can reduce the wear between the components and improve the transmission efficiency of the force. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the technical solution installed on the sewing machine housing.

[0018] Figure 2 This is an exploded diagram of this technical solution.

[0019] Figure numerals: 1. driving motor; 11. output shaft; 2. first-stage transmission assembly; 21. driving crank; 22. plug-in hole one; 23. plug-in rod one; 3. second-stage transmission assembly; 31. lever; 32. transmission connecting rod; 33. presser foot guide; 34. plug-in hole two; 35. guide part; 36. slide groove; 4. middle presser foot mechanism; 41. middle presser foot rod; 42. middle presser foot; 5. receiving mechanism; 51. sliding groove; 52. sliding member; 53. snap-in hole; 6. sewing machine housing; 61. hinge seat. DETAILED DESCRIPTION

[0020] The specific implementation of the technical solution is further described in detail below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, a middle presser foot device for a sewing machine is installed on a sewing machine housing 6, and includes a driving motor 1, a first-stage transmission assembly 2, a second-stage transmission assembly 3 and a middle presser foot mechanism 4, and a receiving mechanism 5 is provided between the first-stage transmission assembly 2 and the second-stage transmission assembly 3, the driving motor 1 is used to lift or lower the middle presser foot 42, the first-stage transmission assembly 2 and the second-stage transmission assembly 3 are used to transmit the force output by the driving motor 1, and the receiving mechanism 5 is used to realize the transmission between the first-stage transmission assembly 2 and the second-stage transmission assembly 3.

[0022] Specifically, Figure 1 and Figure 2 As shown, the driving motor 1 has an output shaft 11, the first-stage transmission assembly 2 includes a driving crank 21, and the driving crank 21 is detachably mounted on the output shaft 11 by screws. The second-stage transmission assembly 3 includes a lever 31 and a transmission connecting rod 32. The rear end of the lever 31 is hinged on the sewing machine housing 6, the front end of the lever 31 is hinged to the upper end of the transmission connecting rod 32, and the lower end of the transmission connecting rod 32 is hinged to the middle presser foot rod 41, so when the lever 31 rotates around the hinge point, the transmission connecting rod 32 can synchronously drive the middle presser foot rod 41 to move, and the middle presser foot mechanism 4 includes a middle presser foot rod 41 and a middle presser foot 42. The middle presser foot rod 41 is vertically mounted on the sewing machine housing 6, and the middle presser foot 42 is mounted at the lower part of the middle presser foot rod 41.

[0023] Furthermore, in order to realize the transmission between the first-stage transmission assembly 2 and the second-stage transmission assembly 3, we set up a receiving mechanism 5, which includes a sliding groove 51 and a sliding member 52. The sliding groove 51 is arranged in the middle of the lever 31, and the sliding member 52 is rotatably installed on the swinging end of the driving crank 21 and movably placed in the sliding groove 51, so the driving motor 1 can first control the rotation of the sliding member 52. At the same time, when the sliding member 52 moves in the sliding groove 51, it can drive the lever 31 to rotate around the hinge point to realize the lifting and lowering of the middle presser foot mechanism 4.

[0024] like Figure 2 As shown, the driving crank 21 is sleeved on the outside of the output shaft 11, and a plug hole 22 is opened at the front end of the driving crank 21. A plug rod 23 is arranged in the plug hole 22, and a sliding member 52 is sleeved on the front end of the plug rod 23. When the front end of the driving crank 21 makes a circular motion, the sliding member 52 slides in the sliding groove 51.

[0025] Furthermore, the surface of the sliding member 52 also has a snap-in hole 53, and the front end of the plug-in rod 23 is embedded in the snap-in hole 53, so that the sliding member 52 can be fixed on the driving crank 21 along the axial direction of the plug-in rod 23, which can effectively prevent the sliding member 52 from detaching from the plug-in rod 23, and at the same time realize the radial rotation of the sliding member 52.

[0026] like Figure 1 and Figure 2 As shown, a presser foot guide 33 is provided at the lower end of the transmission connecting rod 32, and the presser foot guide 33 has a second plug-in hole 34. The upper end of the middle presser foot rod 41 is arranged in the second plug-in hole 34, and the front end of the presser foot guide 33 has a guide portion 35. A vertical slide groove 36 is provided on the inner side of the sewing machine housing 6, and the guide portion 35 is movably placed in the slide groove 36 of the sewing machine housing 6. The design of the guide portion 35 and the slide groove 36 can ensure the stability of the movement of the middle presser foot rod 41.

[0027] like Figure 1 and Figure 2 As shown, the driving motor 1 is arranged inside the sewing machine housing 6 and close to the rear side of the sewing machine housing 6. A hinge seat 61 is arranged on the inner wall of the rear side of the sewing machine housing 6. The rear end of the lever 31 is hinged on the hinge seat 61. The position of the sliding member 52 from the output shaft 11 is smaller than the distance between the sliding member 52 and the hinge point of the lever 31. Therefore, when the sliding member 52 lifts the middle part of the lever 31 for a certain distance, the front end of the lever 31 has moved a larger distance, thereby achieving the effect of saving effort for the driving motor 1.

[0028] Furthermore, the sliding groove 51 is a rectangular groove and is arranged along the length direction of the lever 31. The sliding member 52 is a square member. The upper and lower surfaces of the sliding member 52 are fitted with the upper and lower surfaces of the sliding groove 51. This arrangement can increase the fitting area between the sliding member 52 and the sliding groove 51, and increase the stability of the sliding member 52 moving in the sliding groove 51.

[0029] like Figure 1 and Figure 2 As shown, the length of the sliding groove 51 is greater than the length of the sliding member 52. When the sliding member 52 slides in the sliding groove 51, it also rotates around the plug-in rod 23, so that the smoothness of its transmission can be ensured. When the driving crank 21 swings to a horizontal state, the lever 31 is in a horizontal state and the transmission connecting rod 32 is in a vertical state.

[0030] Furthermore, the length of the lever 31 is greater than or equal to the length of the transmission connecting rod 32, which can ensure a good effort-saving effect when lifting or lowering the middle presser foot rod 41. Because when the driving crank 21 rotates at the same angle, the shorter the lever 31, the farther the receiving mechanism 5 is from the transmission connecting rod 32, and the farther away, the more dispersed the upward lifting force.

[0031] The above shows and describes the basic principle and main features of the technical solution and the advantages of the technical solution. The technicians in this industry should understand that the technical solution is not limited by the above embodiments. The above embodiments and the description only illustrate the principle of the technical solution. Without departing from the spirit and scope of the technical solution, the technical solution will have various changes and improvements, which fall within the scope of the technical solution to be protected. The scope of protection required by the technical solution is defined by the attached claims and their equivalents.

Claims

1. A presser foot device in a sewing machine, characterized in that: include: A drive motor (1) for lifting or lowering the intermediate presser foot (42), wherein the drive motor (1) has an output shaft (11); A first-stage transmission assembly (2), comprising a driving crank (21), wherein the driving crank (21) is mounted on the output shaft (11); A second-stage transmission assembly (3), comprising a lever (31) and a transmission connecting rod (32), wherein the rear end of the lever (31) is hinged to the sewing machine housing (6), the front end of the lever (31) is hinged to the upper end of the transmission connecting rod (32), and the lower end of the transmission connecting rod (32) is hinged to the middle presser foot rod (41); and A middle presser foot mechanism (4), comprising a middle presser foot rod (41) and a middle presser foot (42), wherein the middle presser foot rod (41) is vertically mounted on a sewing machine housing (6), and the middle presser foot (42) is mounted at the bottom of the middle presser foot rod (41); A receiving mechanism (5) is provided between the first-stage transmission assembly (2) and the second-stage transmission assembly (3), and the receiving mechanism (5) comprises: a sliding groove (51) disposed in the middle of the lever (31); and A sliding member (52) is rotatably mounted on the swing end of the driving crank (21) and movably placed in the sliding groove (51); The driving crank (21) drives the lever (31) to rotate around the hinge point through the sliding member (52) to achieve the lifting and lowering of the middle presser foot mechanism (4); The driving crank (21) is sleeved outside the output shaft (11), and a plug-in hole (22) is provided at the front end of the driving crank (21); a plug-in rod (23) is provided in the plug-in hole (22); and the sliding member (52) is sleeved at the front end of the plug-in rod (23); When the front end of the driving crank (21) performs circular motion, the sliding member (52) slides in the sliding groove (51).

2. A presser foot device for a sewing machine according to claim 1, characterized in that: The lower end of the transmission connecting rod (32) is provided with a presser foot guide frame (33), and the presser foot guide frame (33) has a second plug-in hole (34); the upper end of the middle presser foot rod (41) is arranged in the second plug-in hole (34).

3. A presser foot device for a sewing machine according to claim 2, characterized in that: The front end of the presser foot guide frame (33) has a guide portion (35), the inner side of the sewing machine housing (6) is provided with a vertical slide groove (36), and the guide portion (35) is movably placed in the slide groove (36) of the sewing machine housing (6).

4. A presser foot device for a sewing machine according to claim 3, characterized in that: The driving motor (1) is arranged inside the sewing machine housing (6) and close to the rear side of the sewing machine housing (6); A hinge seat (61) is provided on the inner wall of the rear side of the sewing machine housing (6), and the rear end of the lever (31) is hinged on the hinge seat (61).

5. A presser foot device for a sewing machine according to claim 4, characterized in that: The sliding groove (51) is a rectangular groove and is arranged along the length direction of the lever (31); The sliding member (52) is a square member, and the upper and lower surfaces of the sliding member (52) are in contact with the upper and lower surfaces of the sliding groove (51); The length of the sliding groove (51) is greater than the length of the sliding member (52).

6. A presser foot device for a sewing machine according to claim 5, characterized in that: When the driving crank (21) swings to a horizontal state, the lever (31) is in a horizontal state, and the transmission connecting rod (32) is in a vertical state.

7. A presser foot device for a sewing machine according to claim 6, characterized in that: The length of the lever (31) is greater than or equal to the length of the transmission connecting rod (32).

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