Lower feed mechanism for a sewing machine

Abstract

This invention belongs to the field of sewing machine technology, specifically relating to a lower feeding mechanism for a sewing machine, including a motor, a feeding shaft assembly, and a feed dog lifting shaft. A feeding crank (first) is mounted at the rear end of the outer feeding shaft, and a feeding crank (second) is mounted at the rear end of the inner feeding shaft extending from the outer feeding shaft. The other end of the second feeding crank is connected to a motor connecting rod, and the other end of the motor connecting rod is connected to a motor crank, which is mounted on the outer circumference of the motor's main shaft. A feed dog lifting crank is mounted at the rear end of the feed dog lifting shaft. A synchronous connecting rod (first) connects the first feeding crank to the feed dog lifting crank, and a synchronous connecting rod (second) connects the second feeding crank to the feed dog lifting crank. A feed dog lifting crank (first) is mounted at the front end of the outer feeding shaft, and a feed dog lifting crank (second) extends from the front end of the inner feeding shaft extending from the outer feeding shaft. Through the design of the motor, this invention allows for individual control of the speed of the lower feeding dog, thereby adjusting the fabric feeding speed and enabling diverse sewing operations. Operation and control are convenient.

Description

Technical Field

[0001] This invention relates to the field of sewing machine technology, and specifically to a feeding mechanism for a sewing machine. Background Technology

[0002] Sewing machines are widely used as sewing equipment, and flatbed sewing machines are the most frequently used type of sewing machine. In traditional flatbed sewing machines, the feeding mechanism is driven by the rotation of the main shaft, which in turn drives the feeding assembly. The lifting dog linkage and the feeding linkage of the feeding assembly drive the lifting dog shaft and the feeding shaft to swing, and the swinging motion drives the dog holder assembly to move back and forth and up and down, thus achieving the feeding function.

[0003] For example, Chinese invention patent CN109208188A discloses an automatic stitch length adjustment mechanism and sewing machine, including a main shaft and a feed shaft arranged in parallel, and a first feed transmission assembly connected between the main shaft and the feed shaft. The automatic stitch length adjustment mechanism also includes a stitch length adjustment drive source and a stitch length adjustment transmission assembly. The first feed transmission assembly includes a swing seat with a fixed swing axis. The stitch length adjustment drive source is connected to the swing seat through the stitch length adjustment transmission assembly. When the stitch length adjustment drive source is activated, the stitch length adjustment drive source drives the swing seat to rotate around its fixed swing axis through the stitch length adjustment transmission assembly, thereby changing the swing amplitude of the feed shaft driven by the main shaft through the first feed transmission assembly.

[0004] The feeding transmission assembly is precise and complex, with high maintenance costs. Furthermore, the main shaft is usually connected to other transmission mechanisms such as the upper feeding mechanism, making it impossible to control and adjust the feeding speed of the lower feeding assembly independently. Therefore, further improvements to this structure are needed. Summary of the Invention

[0005] The purpose of this invention is to provide a lower feeding mechanism for sewing machines, which solves the problem of complex existing structures through a newly designed feeding transmission mechanism.

[0006] The object of the present invention is achieved as follows: a feeding mechanism for a sewing machine, comprising a motor and a feeding shaft assembly and a lifting tooth shaft rotatably disposed in the machine base, the feeding shaft assembly comprising an inner feeding shaft and an outer feeding shaft sleeved on its outer periphery; Feeding crank one is installed at the rear end of the feeding outer shaft, and feeding crank two is installed at the rear end of the feeding inner shaft extending out of the feeding outer shaft. The other end of feeding crank two is connected to a motor connecting rod, and the other end of the motor connecting rod is connected to a motor crank. The motor crank is installed on the outer circumference of the motor's main shaft. The rear end of the tooth lifting shaft is equipped with a tooth lifting crank, and a synchronous connecting rod is connected between the first feeding crank and the tooth lifting crank, and a synchronous connecting rod is connected between the second feeding crank and the tooth lifting crank. The front end of the outer feeding shaft is equipped with a toothed crank one, and the front end of the inner feeding shaft extends out of the outer feeding shaft and is equipped with a toothed crank two. The front end of the tooth lifting shaft is respectively equipped with tooth lifting fork one and tooth lifting fork two. Tooth frame one is provided between tooth lifting fork one and tooth frame crank one, and tooth frame two is provided between tooth lifting fork two and tooth frame crank two.

[0007] Preferably, one end of the synchronous connecting rod is provided with a transmission pin, and one end of the feeding crank is formed with a transmission connecting rod portion, wherein a strip-shaped hole is provided in the transmission connecting rod portion for the transmission pin to slide.

[0008] Preferably, one end of the transmission pin passes through the synchronous connecting rod and is formed into a limiting part, and the other end of the transmission pin passes through the strip hole and is fitted with a fixing nut. A washer is provided between the fixing nut and the transmission connecting rod part.

[0009] Preferably, one end of the lifting crank is provided with a second transmission pin, and a first synchronous connecting rod and a second synchronous connecting rod are respectively installed on the outer periphery of the second transmission pin.

[0010] Preferably, one end of the transmission pin shaft 2 passes through the synchronizing rod 1 and is provided with a limiting block 3, and a limiting block 4 is provided between the synchronizing rod 2 and the lifting crank.

[0011] Preferably, one end of the feeding crank two is formed with a transmission connecting rod part two, and a fixed seat is movably provided on the outer periphery of the transmission connecting rod part two. A transmission pin three is provided on one side of the fixed seat, and a motor connecting rod and a synchronous connecting rod two are respectively installed on the outer periphery of the transmission pin three.

[0012] Preferably, a first toothed rod pin is provided between one end of the first toothed rod and the first toothed rod crank, a second toothed rod pin is provided at the other end of the first toothed rod, a slider is provided on the outer periphery of the second toothed rod pin, one end of the second toothed rod pin passes through the slider and forms a limit block, one end of the first toothed rod fork is formed with a U-shaped fork for the slider to move, and a feeding tooth is provided on the upper end face of the first toothed rod.

[0013] Preferably, a toothed pin three is provided between one end of the toothed bracket two and the toothed bracket crank two, and a toothed pin four is provided at the other end of the toothed bracket two. A slider two is provided on the outer periphery of the toothed bracket pin four. One end of the toothed bracket pin four passes through the slider two and forms a limit block two. One end of the toothed fork two is formed with a U-shaped fork for the slider two to move. A feeding tooth two is provided on the upper end face of the toothed bracket two.

[0014] The outstanding and beneficial technical effects of this invention compared to the prior art are: This invention, through the design of the motor, enables individual control of the feed dog's speed, thereby adjusting the fabric feeding speed and enabling diverse sewing operations. The operation and control are convenient. When the motor is running, the motor crank drives the motor connecting rod to swing back and forth. Then, the feed crank, synchronous connecting rod, and feed dog lifting crank drive the feed shaft assembly and feed dog lifting shaft to rotate, thereby driving the feed dog to perform a compound motion of up-and-down reciprocating motion and back-and-forth reciprocating motion. Its motion trajectory is similar to an ellipse, realizing the forward and backward movement of the sewing fabric. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure at the bottom of the base.

[0016] Figure 2 Schematic diagram of the three-dimensional structure of the lower feeding mechanism Figure 1 .

[0017] Figure 3 Schematic diagram of the three-dimensional structure of the lower feeding mechanism Figure 2 .

[0018] Figure 4 A bottom view of the lower feeding mechanism Figure 2 .

[0019] Figure 5 for Figure 4 A cross-sectional view of the structure at point AA.

[0020] Figure 6 Exploded view of some parts inside the lower feeding mechanism Figure 1 .

[0021] Figure 7 Exploded view of some parts inside the lower feeding mechanism Figure 2 .

[0022] Reference numerals in the attached diagram: 1-Motor; 2-Feeding shaft assembly; 3-Tooth lifting shaft; 4-Inner feeding shaft; 5-Outer feeding shaft; 6-Feeding crank one; 7-Feeding crank two; 8-Motor connecting rod; 9-Motor crank; 10-Main shaft; 11-Erection crank; 12-Synchronizing link one; 13-Synchronizing link two; 14-Erection crank one; 15-Crank crank two; 16-Crank lifting fork one; 17-Crank lifting fork two; 18-Crank crank one; 19-Crank crank two; 20-Transmission pin one; 21-Transmission connecting rod part one; 22-Strip hole; 23-Limiting part one; 24-Fixing nut; 25-Washer; 26-Transmission pin two; 27-Limiting block three; 28-Limiting block four; 29-Transmission connecting rod part two; 30-Fixed seat; 31-Transmission pin three; 32-Gear bracket pin one; 33-Gear bracket pin two; 34-Slider one; 35-Limit block one; 36-U-shaped fork one; 37-Feeding tooth one; 38-Tooth bracket pin three; 39-Tooth bracket pin four; 40-Slider 2; 41-Limiting block 2; 42-U-shaped fork 2; 43-Feeding tooth 2. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] like Figure 1-7 As shown, a feeding mechanism for a sewing machine includes a motor 1, a feeding shaft assembly 2 and a tooth lifting shaft 3 rotatably disposed in the machine base, the feeding shaft assembly 2 including an inner feeding shaft 4 and an outer feeding shaft 5 sleeved on its outer periphery; Feeding crank 1 6 is installed at the rear end of the feeding outer shaft 5. Feeding crank 2 7 is installed at the rear end of the feeding inner shaft 4 extending out of the feeding outer shaft 5. The other end of the feeding crank 2 7 is connected to the motor connecting rod 8. The other end of the motor connecting rod 8 is connected to the motor crank 9. The motor crank 9 is installed on the outer periphery of the main shaft 10 of the motor 1. The rear end of the tooth lifting shaft 3 is equipped with a tooth lifting crank 11, a synchronous connecting rod 12 is connected between the feeding crank 1 6 and the tooth lifting crank 11, and a synchronous connecting rod 2 13 is connected between the feeding crank 2 7 and the tooth lifting crank 11. The front end of the feeding outer shaft 5 is equipped with a toothed crank 14, and the front end of the feeding inner shaft 4 extends out of the feeding outer shaft 5 and is equipped with a toothed crank 2 15. The front end of the tooth lifting shaft 3 is respectively equipped with a tooth lifting fork 16 and a tooth lifting fork 2 17. A tooth frame 18 is provided between the tooth lifting fork 16 and the tooth frame crank 14, and a tooth frame 2 19 is provided between the tooth lifting fork 2 17 and the tooth frame crank 2 15.

[0025] This invention, through the design of the motor, enables individual control of the feed dog's speed, thereby adjusting the fabric feeding speed and enabling diverse sewing operations. The operation and control are convenient. When the motor is running, the motor crank 9 drives the motor connecting rod 8 to swing back and forth. Then, the feed crank, synchronous connecting rod, and lifting crank drive the feed shaft assembly 2 and lifting shaft 3 to rotate, thereby driving the feed dog to perform a compound motion of up-and-down reciprocating motion and back-and-forth reciprocating motion. Its motion trajectory is similar to an ellipse, realizing the forward and backward movement of the sewing fabric.

[0026] One end of the synchronous connecting rod 12 is provided with a transmission pin 20, and one end of the feeding crank 6 is formed with a transmission connecting rod part 21. The transmission connecting rod part 21 has a strip hole 22 for the transmission pin 20 to slide in. The transmission pin 20 can slide up and down in the strip hole 22, but cannot rotate. When the synchronous connecting rod 12 moves, it will drive the feeding crank 6 to swing through the transmission pin 20, thereby driving the feeding outer shaft 5 to rotate.

[0027] One end of the transmission pin 20 passes through the synchronous connecting rod 12 and forms a limiting part 23. The other end of the transmission pin 20 passes through the strip hole 22 and is fitted with a fixing nut 24, so that the transmission pin 20 is kept connected to the transmission connecting rod part 21 and the transmission pin 20 is prevented from falling out of the strip hole 22. A washer 25 is provided between the fixing nut 24 and the transmission connecting rod part 21 to reduce friction and prevent loosening.

[0028] One end of the lifting crank 11 is provided with a transmission pin 26. Synchronous connecting rod 12 and synchronous connecting rod 23 are respectively installed on the outer periphery of the transmission pin 26, so that synchronous connecting rod 12 and synchronous connecting rod 23 are rotatably connected to the lifting crank 11.

[0029] One end of the transmission pin 26 passes through the synchronous connecting rod 12 and is provided with a limit block 3 27. A limit block 4 28 is provided between the synchronous connecting rod 2 13 and the lifting crank 11 to limit the installation position of the synchronous connecting rod, prevent it from moving laterally, and make its installation stable.

[0030] One end of the feeding crank 27 is formed with a transmission connecting rod 29. A fixed seat 30 is movably provided on the outer periphery of the transmission connecting rod 29. A transmission pin 31 is provided on one side of the fixed seat 30. A motor connecting rod 8 and a synchronous connecting rod 23 are respectively installed on the outer periphery of the transmission pin 31.

[0031] A toothed bracket pin 32 is provided between one end of the toothed bracket 18 and the toothed bracket crank 14. A toothed bracket pin 33 is provided at the other end of the toothed bracket 18. A slider 34 is provided on the outer periphery of the toothed bracket pin 33. One end of the toothed bracket pin 33 passes through the slider 34 and forms a limit block 35. One end of the toothed bracket fork 16 is formed with a U-shaped fork 36 for the slider 34 to move. A feeding tooth 37 is provided on the upper end face of the toothed bracket 18.

[0032] A toothed pin 38 is provided between one end of the toothed bracket 2 19 and the toothed bracket crank 2 15. A toothed bracket pin 49 is provided at the other end of the toothed bracket 2 19. A slider 2 40 is provided on the outer periphery of the toothed bracket pin 49. One end of the toothed bracket pin 49 passes through the slider 2 40 and forms a limit block 2 41. One end of the toothed fork 2 17 is formed with a U-shaped fork 2 42 for the slider 2 40 to move. A feeding tooth 2 43 is provided on the upper end face of the toothed bracket 2 19.

[0033] This invention utilizes a design with two synchronous connecting rods to link the feeding shaft assembly 2 and the tooth lifting shaft 3. When the motor operates, it drives the motor connecting rod 8 via the motor crank 9, which in turn drives both the feeding shaft assembly 2 and the tooth lifting shaft 3 simultaneously through the two synchronous connecting rods. This structure is simple, stable, and reliable.

[0034] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A feeding mechanism for a sewing machine, characterized in that, It includes a motor (1) and a feeding shaft assembly (2) and a tooth lifting shaft (3) rotatably disposed in the machine base. The feeding shaft assembly (2) includes an inner feeding shaft (4) and an outer feeding shaft (5) sleeved on its outer periphery. Feeding crank one (6) is installed at the rear end of the feeding outer shaft (5), and feeding crank two (7) is installed at the rear end of the feeding inner shaft (4) extending out of the feeding outer shaft (5). The other end of the feeding crank two (7) is connected to the motor connecting rod (8), and the other end of the motor connecting rod (8) is connected to the motor crank (9). The motor crank (9) is installed on the outer periphery of the main shaft (10) of the motor (1). The tooth lifting shaft (3) is equipped with a tooth lifting crank (11) at its rear end. A synchronous connecting rod (12) is connected between the first feeding crank (6) and the tooth lifting crank (11), and a synchronous connecting rod (13) is connected between the second feeding crank (7) and the tooth lifting crank (11). The front end of the feeding outer shaft (5) is equipped with a toothed crank one (14), and the front end of the feeding inner shaft (4) extends out of the feeding outer shaft (5) and is equipped with a toothed crank two (15). The front end of the lifting shaft (3) is respectively equipped with a lifting fork one (16) and a lifting fork two (17). A tooth frame one (18) is provided between the lifting fork one (16) and the tooth frame crank one (14), and a tooth frame two (19) is provided between the lifting fork two (17) and the tooth frame crank two (15).

2. The feeding mechanism for a sewing machine according to claim 1, characterized in that: One end of the synchronous connecting rod (12) is provided with a transmission pin (20), and one end of the feeding crank (6) is formed with a transmission connecting rod part (21). The transmission connecting rod part (21) is provided with a strip hole (22) for the transmission pin (20) to slide.

3. The feeding mechanism for a sewing machine according to claim 2, characterized in that: One end of the transmission pin (20) passes through the synchronous connecting rod (12) and forms a limiting part (23). The other end of the transmission pin (20) passes through the strip hole (22) and is fitted with a fixing nut (24). A washer (25) is provided between the fixing nut (24) and the transmission connecting rod part (21).

4. The feeding mechanism for a sewing machine according to claim 1, characterized in that: One end of the lifting crank (11) is provided with a transmission pin (26), and a synchronous connecting rod (12) and a synchronous connecting rod (13) are respectively installed on the outer periphery of the transmission pin (26).

5. The feeding mechanism for a sewing machine according to claim 4, characterized in that: One end of the transmission pin (26) passes through the synchronous connecting rod (12) and is provided with a limit block (27). A limit block (28) is provided between the synchronous connecting rod (13) and the lifting crank (11).

6. The feeding mechanism for a sewing machine according to claim 1, characterized in that: One end of the feeding crank two (7) is formed with a transmission connecting rod part two (29). A fixed seat (30) is movably provided on the outer periphery of the transmission connecting rod part two (29). A transmission pin three (31) is provided on one side of the fixed seat (30). A motor connecting rod (8) and a synchronous connecting rod two (13) are respectively installed on the outer periphery of the transmission pin three (31).

7. The feeding mechanism for a sewing machine according to claim 1, characterized in that: A toothed pin (32) is provided between one end of the toothed bracket (18) and the toothed bracket crank (14). A toothed pin (33) is provided at the other end of the toothed bracket (18). A slider (34) is provided on the outer periphery of the toothed pin (33). One end of the toothed pin (33) passes through the slider (34) and forms a limit block (35). One end of the toothed fork (16) is formed with a U-shaped fork (36) for the slider (34) to move. A feeding tooth (37) is provided on the upper surface of the toothed bracket (18).

8. The feeding mechanism for a sewing machine according to claim 1, characterized in that: A toothed pin three (38) is provided between one end of the toothed bracket two (19) and the toothed bracket crank two (15). A toothed bracket pin four (39) is provided at the other end of the toothed bracket two (19). A slider two (40) is provided on the outer periphery of the toothed bracket pin four (39). One end of the toothed bracket pin four (39) passes through the slider two (40) and forms a limit block two (41). One end of the toothed fork two (17) is formed with a U-shaped fork two (42) for the slider two (40) to move. A feeding tooth two (43) is provided on the upper end face of the toothed bracket two (19).

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