Presser foot lifting mechanism for lockstitch sewing machine, stitch length adjusting mechanism and lockstitch sewing machine

Abstract

The utility model belongs to the technical field of lockstitch sewing machines, and particularly relates to a presser foot lifter for a lockstitch sewing machine, a stitch length adjusting mechanism and the lockstitch sewing machine. A presser foot lifter driving wheel and a stitch length adjusting crank are respectively installed on an output shaft of a stepping motor, and one end of the stitch length adjusting crank is connected with a stitch length adjusting connecting rod. A presser foot lifting protruding face and a stitch length adjusting concave face are formed on the front end face of the presser foot lifting driving wheel, a pushing part for pushing the presser foot lifting protruding face is arranged at the lower end of the presser foot lifting lower lever, the upper end of the presser foot lifting lower lever is connected with a lower connecting rod, and the upper end of the lower connecting rod is connected with an upper connecting rod. Through the design of the stepping motor, in the actual working process, the output shaft drives the presser foot lifting driving wheel and the stitch length adjusting crank to rotate, so that the presser foot lifting lower lever is pushed to rotate, the presser foot lifting acts or the swing seat is driven to rotate, the stitch length adjusting action is achieved, the structure is simple, parts are simplified, and cost is low.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of flat sewing machine, especially a lifting presser foot, stitch length adjusting mechanism and flat sewing machine for flat sewing machine. BACKGROUND

[0002] At present, the sewing machine needs to lift the presser foot and adjust the stitch length during use. In the existing structure, some will produce a large noise. For example, the stitch length adjusting mechanism of the ordinary sewing machine is mostly completed by a stitch length dial. During backstitching, a large impact force is generated, thereby causing noise and vibration of the whole machine, which cannot be avoided by the traditional structure. Some structures are separately controlled. For example, the ordinary lifting presser foot structure relies on an electromagnet for driving. In the working state, the electromagnet is pushed to the bottom, and the height of the lifting presser foot reaches the highest. The height of the lifting presser foot cannot be adjusted. At the same time, the electromagnet generates a large impact in the high attraction state, which has a large negative effect on the noise and vibration of the whole machine. At the same time, the ordinary sewing machine lifting presser foot system uses an electromagnet system, so that the overall mechanism has a very large volume, the overall functional structure is complex, the cost is high, and the upgrading and transformation space of the sewing machine is hindered. Therefore, the above structure needs to be further improved. SUMMARY

[0003] The utility model aims at providing a lifting presser foot and stitch length adjusting mechanism for a flat sewing machine, which is driven by a stepping motor to solve the problems of complex structure and high cost.

[0004] The utility model discloses a lifting presser foot and stitch length adjusting mechanism for a flat sewing machine, which comprises a stepping motor, a swing seat and a lifting presser foot lower lever. A lifting presser foot driving wheel and a stitch length adjusting crank are respectively installed on the output shaft of the stepping motor. One end of the stitch length adjusting crank is connected with a stitch length adjusting connecting rod, and the other end of the stitch length adjusting connecting rod is connected with the swing seat. The front end face of the lifting presser foot driving wheel is respectively formed with a lifting presser foot convex surface and a stitch length adjusting concave surface. The lower end of the lifting presser foot lower lever is provided with a pushing part for the lifting presser foot convex surface. The middle end of the lifting presser foot lower lever is rotationally connected with a machine body. The upper end of the lifting presser foot lower lever is connected with a lower connecting rod. The upper end of the lower connecting rod is connected with an upper connecting rod. The upper end of the upper connecting rod is connected with a lifting presser foot upper lever. The middle end of the lifting presser foot upper lever is rotationally connected with the machine body. The lower end of the lifting presser foot upper lever is connected with a presser foot assembly through a pull rod.

[0005] Preferably, a strip-shaped adjusting hole is formed in the lower connecting rod, and a fixing hole is formed in the upper connecting rod. A fastener is installed in the strip-shaped adjusting hole and the fixing hole.

[0006] Preferably, the upper end of the lifting presser foot upper lever is connected with a connecting rod two. The lower end of the connecting rod two is connected with a knee leaning assembly.

[0007] Preferably, a transition arc surface is formed between the presser foot convex surface and the stitch length adjustment concave surface.

[0008] Preferably, the pushing part is a roller, and the roller is rotatably arranged at the lower end of the presser foot lower lever through a fixing member.

[0009] Preferably, the stitch length adjustment crank is arranged at the outer end of the output shaft, and one end of the stitch length adjustment crank is formed with an eccentric part, and the eccentric part is connected with a stitch length adjustment connecting rod.

[0010] A flat sewing machine comprises the presser foot and stitch length adjustment mechanism for the flat sewing machine according to any one of the above.

[0011] Compared with the prior art, the utility model has the advantages of the following:

[0012] The utility model discloses a design of the stepping motor, and in actual working process, the output shaft drives the presser foot driving wheel and stitch length adjustment crank to rotate, thereby pushing the presser foot lower lever to rotate, and the presser foot action or drives the swing seat to rotate, so as to realize the stitch length adjustment action, which is simple in structure, simplifies parts, and is low in cost. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is the three-dimensional structure schematic diagram of the utility model.

[0014] Figure 2 It is the structure schematic diagram of the presser foot and stitch length adjustment mechanism Figure 1 .

[0015] Figure 3 It is the structure schematic diagram of the presser foot and stitch length adjustment mechanism Figure 2 .

[0016] Figure 4 It is the structure schematic diagram of the presser foot mechanism.

[0017] Reference Signs: 1-Stepping motor;2-Swing seat;3-Presser foot lower lever;4-Output shaft;

[0018] 5-Presser foot driving wheel;6-Stitch length adjustment crank;7-Stitch length adjustment connecting rod;8-Presser foot convex surface;9-Stitch length adjustment concave surface;10-Pushing part;11-Lower connecting rod;12-Upper connecting rod;13-Presser foot upper lever;14-Pull rod one;15-Strip-shaped adjustment hole;16-Fixing hole;17-Fastener;18-Connecting rod two;

[0019] 19-Transition arc surface;20-Roller;21-Fixing member;22-Eccentric part;23-Machine body. DETAILED DESCRIPTION

[0020] The specific embodiments of the utility model will be explained in further detail below with reference to the drawings.

[0021] As shown in Figures 1-4 A kind of lifting presser foot, stitch length adjusting mechanism for flat bed sewing machine, including step motor 1, swing seat 2 and lifting presser foot lower lever 3, lifting presser foot driving wheel 5 and stitch length adjusting crank 6 are respectively installed on the output shaft 4 of step motor 1, one end of stitch length adjusting crank 6 is connected with stitch length adjusting connecting rod 7, the other end of stitch length adjusting connecting rod 7 is connected with swing seat 2, step motor 1 drives swing seat 2 to rotate by stitch length adjusting connecting rod 7, makes swing seat 2 be located at different angles, can realize the adjustment of the size of sewing machine stitch length, the front end face of lifting presser foot driving wheel 5 is profiled with lifting presser foot convex surface 8 and stitch length adjusting concave surface 9 respectively, the lower end of lifting presser foot lower lever 3 is provided with the pusher 10 for lifting presser foot convex surface 8 to push, the middle end of lifting presser foot lower lever 3 is rotatably connected with machine body 23, the upper end of lifting presser foot lower lever 3 is connected with lower connecting rod 11, the upper end of lower connecting rod 11 is connected with upper connecting rod 12, the upper end of upper connecting rod 12 is connected with lifting presser foot upper lever 13, the middle end of lifting presser foot upper lever 13 is rotatably connected with machine body 23, the lower end of lifting presser foot upper lever 13 is connected with presser foot assembly by pull rod one 14, when step motor 1 drives lifting presser foot driving wheel 5 to rotate to set angle, lifting presser foot convex surface 8 will push lifting presser foot lower lever 3 to rotate by pusher 10, in turn drives presser foot assembly to act by lower connecting rod 11, upper connecting rod 12, lifting presser foot upper lever 13, pull rod one 14, executes lifting presser foot action.

[0022] The utility model discloses a design through step motor, in actual working process, drive lifting presser foot driving wheel 5 and stitch length adjusting crank 6 to rotate by output shaft 4, to push lifting presser foot lower lever 3 to rotate, make lifting presser foot action or drive swing seat 2 to rotate, to realize stitch length adjusting action, this structure is simple, simplifies spare part, and cost is lower.

[0023] Combining Figure 3 And Figure 4 , the lower connecting rod 11 is internally provided with a strip-shaped adjusting hole 15, the upper connecting rod 12 is internally provided with a fixing hole 16, and the fixing hole 16 and the strip-shaped adjusting hole 15 are internally provided with a fastener 17, through the design of the strip-shaped adjusting hole 15, in the actual installation process, the relative installation position between the lower connecting rod 11 and the upper connecting rod 12 can be adjusted, so as to be suitable for various specifications of lifting presser foot mechanisms and be suitable for installation on different machine models.

[0024] The upper end of the lifting presser foot upper lever 13 is connected with a connecting rod two 18, the lower end of the connecting rod two 18 is connected with a knee leaning assembly, so that the lifting presser foot action can be controlled by the motor or manually.

[0025] The transition arc surface 19 is formed between the lifting presser foot convex surface 8 and the stitch length adjusting concave surface 9.

[0026] The pushing part 10 is a roller 20, which is rotatably arranged at the lower end of the lower presser foot lever 3 through a fixing part 21, can reduce the friction between the pushing part 10 and the lifting presser foot driving wheel, reduce the abrasion, and prolong the service life.

[0027] The stitch length adjusting crank 6 is arranged at the outer end of the output shaft 4, one end of the stitch length adjusting crank 6 is formed with an eccentric part 22, and the eccentric part 22 is connected with the stitch length adjusting connecting rod 7.

[0028] The utility model discloses a flat sewing machine, including the lifting presser foot, stitch length adjusting mechanism for flat sewing machine as any above.

[0029] The basic principle and main features of the utility model and the advantages of the utility model are shown and described above. It should be understood by the person skilled in the art that the utility model is not limited by the above-mentioned embodiments, and the above-mentioned embodiments and the description in the specification are only for illustrating the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model can have various changes and improvements, and these changes and improvements all fall within the scope of the utility model claimed. The scope of protection of the utility model is defined by the appended claims and their equivalents.

Claims

1. A presser foot, stitch length adjusting mechanism for a lockstitch machine, characterized by, Including step motor (1), swing seat (2) and lift the foot under lever (3), the output shaft (4) of step motor (1) is installed with lift the foot drive wheel (5) and needle spacing adjustment crank (6) respectively, one end of needle spacing adjustment crank (6) is connected with needle spacing adjustment connecting rod (7), the other end of needle spacing adjustment connecting rod (7) is connected with swing seat (2), the front end face of lift the foot drive wheel (5) is shaped with lift the foot convex surface (8) and needle spacing adjustment concave surface (9) respectively, the lower end of lift the foot under lever (3) is provided with the pusher (10) for lift the foot convex surface (8) push, the middle end of lift the foot under lever (3) is rotatably connected with machine body (23), the upper end of lift the foot under lever (3) is connected with lower connecting rod (11), the upper end of lower connecting rod (11) is connected with upper connecting rod (12), the upper end of upper connecting rod (12) is connected with lift the foot upper lever (13), the middle end of lift the foot upper lever (13) is rotatably connected with machine body (23), the lower end of lift the foot upper lever (13) is connected with foot assembly through pull rod one (14).

2. The presser foot lifting, stitch length regulating mechanism for a lockstitch sewing machine according to claim 1, characterized in that: The strip-shaped adjusting hole (15) is formed in the lower connecting rod (11), the fixing hole (16) is formed in the upper connecting rod (12), and the fastener (17) is installed in the strip-shaped adjusting hole (15) and the fixing hole (16).

3. The presser foot lifting and stitch length regulating mechanism for use in a lockstitch sewing machine according to claim 1, characterized in that: The upper end of the lift the foot upper lever (13) is connected with the connecting rod two (18), and the knee leaning assembly is connected to the lower end of the connecting rod two (18).

4. The presser foot lifting and stitch length regulating mechanism for use in a lockstitch sewing machine according to claim 1, characterized in that: The transition arc surface (19) is formed between the lift the foot convex surface (8) and the needle spacing adjustment concave surface (9).

5. The presser foot lifting and stitch length regulating mechanism for use in a lockstitch sewing machine according to claim 1, characterized in that: The pusher (10) is a roller (20), and the roller (20) is rotatably arranged at the lower end of the lift the foot under lever (3) through the fixing piece (21).

6. The presser foot lifting and stitch length regulating mechanism for use in a lockstitch sewing machine according to claim 1, characterized in that: The needle spacing adjustment crank (6) is arranged at the outer end of the output shaft (4), one end of the needle spacing adjustment crank (6) is formed with the eccentric portion (22), and the needle spacing adjustment connecting rod (7) is connected to the eccentric portion (22).

7. A flat bed sewing machine characterized by: The presser foot and needle spacing adjustment mechanism for a lockstitch sewing machine is provided.

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