Stitch length and presser foot lifting adjusting device of sewing machine

Abstract

The utility model discloses a stitch length and presser foot lifting adjusting device of a sewing machine, and particularly relates to the technical field of sewing machines, the stitch length and presser foot lifting adjusting device comprises a driving motor, a presser foot lifting cam, a presser foot lifting lever and a swing seat, the presser foot lifting cam is connected to a motor shaft of the driving motor, and the presser foot lifting cam is used for driving the presser foot lifting lever to work; a stitch length cam is further connected to the motor shaft and drives the swing seat to swing through a stitch length crank and a stitch length adjusting connecting rod, one end of the stitch length adjusting connecting rod is hinged to the stitch length crank, and the other end of the stitch length adjusting connecting rod is hinged to the swing seat. According to the utility model, the stitch length crank only intermittently rotates along with the rotation of the stitch length cam so as to drive the swinging seat to swing, and the swinging seat does not rotate along with the circumferential vibration of the presser foot lifting cam during working, so that the swinging seat is ensured not to swing unnecessarily, the working stability is ensured, and the working efficiency is improved. Meanwhile, vibration and noise can be reduced.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology, and relates to a sewing machine, and particularly to a sewing machine stitch length and presser foot adjustment device. Background Technology

[0002] Sewing machines require pressing foot lifting and stitch length adjustment during operation. Existing designs, such as the one disclosed in Chinese Patent [Authorization Announcement No.: CN111593497A], include a presser foot assembly and a swing seat for adjusting stitch length. The key feature is the inclusion of a stepper motor. This stepper motor drives the presser foot lifting assembly to perform the pressing action and drives the swing seat to perform the rotational swing action. A presser foot lifting cam is connected to the stepper motor, and the presser foot lifting cam includes a stitch length travel surface and a presser foot travel surface. The presser foot lifting assembly includes a presser foot lever, a pressure rod, and a presser foot. The presser foot is connected to the bottom end of the pressure rod. One end of the presser foot lever is connected to the pressure rod via a linkage mechanism, and the other end of the presser foot lever is adapted to the presser foot stroke surface. The stepper motor includes an output shaft, and the presser foot cam is fixedly connected to the output shaft, with the cam located at the end closest to the stepper motor body. A pin pitch drive handle is fixedly connected to the other end of the output shaft, away from the stepper motor body. The pin pitch drive handle is connected to the swing seat via a pin pitch pull rod. In the technical solution disclosed in this patent, since both the pin pitch drive handle and the presser foot cam are fixedly connected to the drive shaft of the stepper motor, when the presser foot cam rotates and drives the presser foot lever, circumferential vibration is generated. This causes the pin pitch drive handle to rotate, resulting in vibration of the pin pitch adjustment components such as the swing seat, affecting the working stability. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a sewing machine stitch length and presser foot adjustment device.

[0004] The purpose of this utility model can be achieved through the following technical solution: a stitch length and presser foot adjustment device for a sewing machine, comprising a drive motor, a presser foot cam, a presser foot lever, and a swing seat. The presser foot cam is connected to the motor shaft of the drive motor and is used to drive the presser foot lever to work. The characteristic is that a stitch length cam is also connected to the motor shaft. The stitch length cam drives the swing seat to swing through a stitch length crank and a stitch length adjustment linkage. One end of the stitch length adjustment linkage is hinged to the stitch length crank, and the other end is hinged to the swing seat.

[0005] In the above-mentioned stitch length and presser foot adjustment device for the sewing machine, the middle part of the stitch length crank is hinged to the sewing machine housing by a screw at the end of the feed adjuster shaft. One end of the stitch length crank is rotatably connected to a stitch length roller, the wheel surface of the stitch length roller abuts against the wheel surface of the stitch length cam, and the other end of the stitch length crank is hinged to one end of the stitch length adjustment linkage.

[0006] In the above-mentioned sewing machine's stitch length and presser foot adjustment device, a bolt assembly for connecting a reverse stitch feed spring is inserted through the stitch length adjustment linkage. One end of the reverse stitch feed spring is connected to the bolt assembly, and the other end is connected to a fixing plate. The fixing plate is fixedly connected to the sewing machine's housing.

[0007] In the above-mentioned sewing machine's stitch length and presser foot adjustment device, the stitch length cam includes a circular plate-shaped stitch length cam body and a stitch length cam drive block located on the outer circumferential surface of the stitch length cam body and protruding outward in a comma shape. The stitch length cam drive block includes a concave drive surface one and a convex drive surface two.

[0008] In the above-mentioned sewing machine's stitch length and presser foot adjustment device, the presser foot cam and the stitch length cam are sequentially connected to the motor shaft, and the stitch length cam is connected to the free end of the motor shaft. The presser foot cam includes a circular presser foot cam body and a presser foot cam drive block located on the outer circumferential surface of the stitch length cam body and protruding outward. The presser foot cam drive block has a driving surface with varying heights on one side wall facing the stitch length cam.

[0009] In the above-mentioned sewing machine's stitch length and presser foot adjustment device, the middle part of the presser foot lever is hinged to the sewing machine housing by a presser foot lever shaft screw. One end of the presser foot lever is connected to the presser foot assembly through a presser foot pull rod, and the other end is connected to a presser foot roller. The presser foot roller is abutted against the drive surface three of the presser foot cam drive block.

[0010] Compared with the prior art, in this utility model, when the presser foot lifting assembly moves up and down with the presser foot lifting cam, the needle pitch crank will only rotate intermittently with the rotation of the needle pitch cam, thereby driving the swing seat to swing. It will not rotate due to the circumferential vibration of the presser foot lifting cam during operation, thus ensuring that the swing seat will not swing unnecessarily, ensuring the stability of the operation, and also reducing vibration and noise. Attached Figure Description

[0011] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0012] Figure 2 This is a three-dimensional structural diagram of the present invention from another angle.

[0013] Figure 3 This is an exploded view of this utility model.

[0014] Figure 4 This is an exploded view of the present invention from another angle.

[0015] Figure 5This is a schematic diagram of the needle-pitch cam in this utility model.

[0016] Figure 6 This is a schematic diagram of the lifting foot cam in this utility model.

[0017] In the diagram: 1. Drive motor; 2. Presser foot lifting cam; 201. Presser foot lifting cam drive block; 202. Drive surface three; 3. Presser foot lifting lever; 4. Swing seat; 5. Motor shaft; 6. Stitch pitch cam; 601. Stitch pitch cam drive block; 602. Drive surface one; 603. Drive surface two; 7. Stitch pitch crank; 8. Stitch pitch adjusting linkage; 9. Feed adjuster shaft end screw; 10. Stitch pitch roller; 11. Backstitch feeding tension spring; 12. Presser foot lifting lever shaft screw; 13. Presser foot lifting rod; 14. Presser foot lifting roller; 15. Presser foot lifting assembly; 16. Fixing plate. Detailed Implementation

[0018] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0019] Reference Figures 1-4 This embodiment is a stitch length and presser foot adjustment device for a sewing machine, including a drive motor 1, a presser foot cam 2, a presser foot lever 3, a swing seat 4, and a stitch length cam 6. The presser foot cam 2 and the stitch length cam 6 are connected to the motor shaft 5 in sequence. The presser foot cam 2 is used to drive the presser foot lever 3 to work, and the stitch length cam 6 is connected to the free end of the motor shaft 5 and is used to drive the swing seat 4 to swing. The stitch distance cam 6 is connected to the swing seat 4 via the stitch distance crank 7 and the stitch distance adjustment linkage 8, thereby driving the swing seat 4 to swing. One end of the stitch distance adjustment linkage 8 is hinged to the stitch distance crank 7, and the other end is hinged to the swing seat 4. The middle part of the stitch distance crank 7 is hinged to the sewing machine housing via the feed adjuster shaft end screw 9. One end of the stitch distance crank 7 is rotatably connected to the stitch distance roller 10, and the wheel surface of the stitch distance roller 10 abuts against the wheel surface of the stitch distance cam 6. The other end of the stitch distance crank 7 is hinged to one end of the stitch distance adjustment linkage 8. A bolt assembly for connecting the backstitch feed spring 11 is inserted through the stitch distance adjustment linkage 8. One end of the backstitch feed spring 11 is connected to the bolt assembly, and the other end is connected to the fixed plate 16. The fixed plate 16 is fixed to the sewing machine housing.

[0020] Combination Figure 5The stitch cam 6 includes a circular stitch cam body and a stitch cam drive block 601 located on the outer circumference of the stitch cam body and protruding outward in a comma shape. The stitch cam drive block 601 includes a concave drive surface 602 and a convex drive surface 603. When the stitch cam 6 rotates counterclockwise as viewed from the machine head, the concave drive surface 602 of the stitch cam drive block 601 actuates the stitch roller 10 and drives the swing seat 4 to swing. When the stitch cam 6 rotates clockwise as viewed from the machine head, the convex drive surface 603 of the stitch cam drive block 601 drives the swing seat 4 to swing to perform a reverse sewing operation.

[0021] Combination Figure 6 The presser foot cam 2 includes a circular presser foot cam body and a presser foot cam drive block 201 located on the outer circumferential surface of the stitch distance cam body and protruding outward. The presser foot cam drive block 201 has a drive surface 202 with varying heights on one side wall facing the stitch distance cam 6. The middle part of the presser foot lever 3 is hinged to the sewing machine housing by a presser foot lever shaft screw 12. One end of the presser foot lever 3 is connected to the presser foot assembly 15 through a presser foot pull rod 13, and the other end is connected to a presser foot roller 14. The presser foot roller 14 abuts against the drive surface 202 of the presser foot cam drive block 201.

[0022] In this embodiment, when viewed from the machine head direction, when the lifting foot cam 2 rotates counterclockwise, the lifting foot assembly 15 rises and falls with the rotation of the lifting foot cam 2; the stitch distance cam drive block 601 on the stitch distance cam 6 is separated from the stitch distance roller 10, and the stitch distance roller 10 only abuts against the outer peripheral surface of the stitch distance cam 6 body without the protruding stitch distance cam drive block 601, and the outer peripheral surface on this movement stroke is a gentle arc surface, the stitch distance crank 7 does not vibrate with the rotation of the stitch distance roller 10, thus preventing unnecessary vibration of the connected stitch distance adjustment linkage 8 and swing seat 4, ensuring the stability of the operation, and also reducing noise.

[0023] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A stitch length and presser foot adjustment device for a sewing machine, comprising a drive motor (1), a presser foot cam (2), a presser foot lever (3), and a swing seat (4), wherein the presser foot cam (2) is connected to the motor shaft (5) of the drive motor (1), and the presser foot cam (2) is used to drive the presser foot lever (3) to work, characterized in that, The motor shaft (5) is also connected to a needle pitch cam (6). The needle pitch cam (6) drives the swing seat (4) to swing through the needle pitch crank (7) and the needle pitch adjusting linkage (8). One end of the needle pitch adjusting linkage (8) is hinged to the needle pitch crank (7), and the other end is hinged to the swing seat (4).

2. The stitch length and presser foot adjustment device for a sewing machine according to claim 1, characterized in that, The middle part of the stitch pitch crank (7) is hinged to the sewing machine housing by the feed adjuster shaft end screw (9). One end of the stitch pitch crank (7) is rotatably connected to the stitch pitch roller (10). The wheel surface of the stitch pitch roller (10) abuts against the wheel surface of the stitch pitch cam (6). The other end of the stitch pitch crank (7) is hinged to one end of the stitch pitch adjusting linkage (8).

3. The stitch length and presser foot adjustment device for a sewing machine according to claim 2, characterized in that, The needle spacing linkage (8) is fitted with a bolt assembly for connecting the backstitch feed spring (11). One end of the backstitch feed spring (11) is connected to the bolt assembly, and the other end is connected to the fixing plate (16). The fixing plate (16) is fixed to the housing of the sewing machine.

4. The stitch length and presser foot adjustment device for a sewing machine according to claim 1, 2, or 3, characterized in that, The pin-pitch cam (6) includes a pin-pitch cam body in the shape of a circular plate and a pin-pitch cam drive block (601) located on the outer peripheral surface of the pin-pitch cam body and protruding outward in the shape of a comma. The pin-pitch cam drive block (601) includes a concave drive surface one (602) and a convex drive surface two (603).

5. The stitch length and presser foot adjustment device for a sewing machine according to claim 1, characterized in that, The lifting foot cam (2) and the needle pitch cam (6) are connected to the motor shaft (5) in sequence, and the needle pitch cam (6) is connected to the free end of the motor shaft (5). The lifting foot cam (2) includes a lifting foot cam body in the shape of a circular plate and a lifting foot cam drive block (201) located on the outer peripheral surface of the needle pitch cam body and protruding outward. The lifting foot cam drive block (201) has a driving surface three (202) with high and low undulations on one side wall facing the needle pitch cam (6).

6. The stitch length and presser foot adjustment device for a sewing machine according to claim 5, characterized in that, The middle part of the presser foot lever (3) is hinged to the sewing machine housing by the presser foot lever shaft screw (12). One end of the presser foot lever (3) is connected to the presser foot assembly (15) through the presser foot pull rod (13), and the other end is connected to a presser foot roller (14). The presser foot roller (14) is abutted against the drive surface three (202) of the presser foot cam drive block (201).

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