A motion device for the feed dog of a high-platform column sewing machine

Abstract

This invention provides a motion device for the feed dog of a high-platform sewing machine, belonging to the field of sewing machine technology. It solves the problem of inconvenient installation of existing feed dog motion devices. The motion device for the feed dog of this high-platform sewing machine includes a lower feed shaft, a lifting shaft, a feed dog frame, a slide rod, a feed crank, and a lifting rod connecting rod. The left end of the lifting shaft is fixedly connected to the lifting crank. The slide rod is disposed in the column and can slide up and down and swing back and forth relative to the column. The top of the slide rod is fixedly connected to the feed dog, and the bottom of the slide rod is hinged to the middle of the feed dog frame. The top of the feed crank is fixedly connected to the left end of the lower feed shaft, and the bottom of the feed crank is hinged to the rear end of the feed dog frame. The top of the lifting rod is hinged to the lifting crank, and the bottom of the lifting rod is hinged to the front end of the feed dog frame. The bottom of the slide rod has a curved section that forms a clearance space. This motion device for the feed dog of this high-platform sewing machine has the advantages of convenient installation and good stability.

Description

Technical Field

[0001] This invention belongs to the field of sewing machine technology and relates to a motion device for the feed dog of a high-platform column sewing machine. Background Technology

[0002] A sewing machine is a machine that uses a single sewing thread to create a stitch on fabric, allowing one or more layers of fabric to interweave or sew together. A sewing machine includes a feed dog, which feeds the fabric through the periodic movement of the feed dog along an approximately elliptical trajectory.

[0003] Existing feed dog motion structures, such as the sewing fabric conveying device and sewing equipment disclosed in Chinese patent literature [Patent No.: 201920961660.4; Application Publication No.: CN211005885U], include: a needle; a first drive assembly, which is connected to the needle drive to drive the needle to move up and down reciprocally; a feed assembly, including a needle plate and a feed dog, the needle plate being located below the needle, the needle plate having a feed port, and the feed dog being located in the feed port; and a swing mechanism, including a first swing assembly and a second swing assembly, the first swing assembly being located on the bottom side of the needle plate to drive the feed dog to swing, and the second swing assembly being connected to the needle drive to drive the needle to swing.

[0004] In this type of sewing equipment, the bottom of the feed dog base is fixedly connected to the first feed shaft, and the top of the feed dog base is hinged to the feed dog bracket. A vertically oriented sliding groove is formed in the slide rod, and a sliding block is embedded in the sliding groove. The sliding block is hinged to a mounting base fixed to the sewing machine base plate. This hinge point causes the feed dog to undergo an additional reversal. Therefore, an additional deflector is needed in the sewing equipment to perform a reversal to counteract the additional reversal caused by the hinge point. However, installing the deflector requires adjustments to the connections of existing components. Furthermore, the internal space of the sewing equipment is limited, making the installation of the deflector cumbersome. Moreover, the installation of the deflector increases potential points of failure and reduces the stability of the sewing equipment. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a motion device for the feed teeth of a high-platform column sewing machine. The technical problem solved is how to make the motion device easy to install and how to ensure its stability.

[0006] The objective of this invention can be achieved through the following technical solution: A motion device for the feed dog of a high-platform sewing machine, comprising a lower feed shaft, a lifting shaft, a dog holder, and a slide rod. The left end of the lifting shaft is fixedly connected to a lifting crank. The slide rod is disposed in the column and can slide up and down and swing back and forth relative to the column. The top of the slide rod is fixedly connected to the feed dog, and the bottom of the slide rod is hinged to the middle part of the dog holder. The motion device further comprises a feed crank and a long, strip-shaped lifting rod. The top of the feed crank is fixedly connected to the left end of the lower feed shaft, and the bottom of the feed crank is hinged to the rear end of the dog holder. The top of the lifting rod is hinged to the lifting crank, and the bottom of the lifting rod is hinged to the front end of the dog holder. The bottom of the slide rod has an arc-shaped curved section, which forms a clearance space for avoiding the rotary hook base.

[0007] During operation, the lower feed shaft drives the feed dog to move back and forth via the feed crank, feed dog holder, and slide rod. The lifting feed shaft drives the feed dog to move up and down via the lifting feed crank, lifting feed connecting rod, feed dog holder, and slide rod, thus creating a periodic motion of the feed dog in an approximately elliptical trajectory to feed the fabric. In this motion device, the feed crank extends downwards, with its top fixed to the lower feed shaft and its bottom hinged to the rear end of the feed dog holder. This orientation is the opposite of existing technologies where the feed crank extends upwards, meaning the direction in which the feed crank drives the feed dog holder to move back and forth is opposite. This offsets the hinged reversal between the slide rod and the column, eliminating the need for an additional steering mechanism on the sewing machine, simplifying installation, reducing the failure rate, and improving the stability of the motion device. The downward-extending feed crank and elongated lifting feed connecting rod lower the feed dog holder's mounting position. The bottom of the slide rod has an arc-shaped curved section, which avoids the installation of the rotary hook base, resulting in a rational layout and convenient installation of the motion device.

[0008] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the feed dog is elongated, with both its front and rear ends pointing upwards. The bottom of the feed crank has a feed groove, the rear end of the feed dog is embedded in the feed groove and hinged to the feed crank via a feed hinge shaft, the front end of the feed dog has a hinge groove, and the bottom of the lifting rod is embedded in the hinge groove and hinged to the feed dog via a lifting hinge shaft. The tooth holder is long and narrow, occupying little space, allowing for a reasonable arrangement and convenient installation of the motion device. Both ends of the tooth holder are angled upwards, enabling better hinged connection with the feed crank and the tooth lifting connecting rod. The rear end of the tooth holder is embedded in the feed groove and hinged to the feed crank via a feed hinge shaft, giving the feed crank two push points and allowing it to better propel the tooth holder forward and backward. The bottom of the tooth lifting connecting rod is embedded in the hinge groove and hinged to the tooth holder via a tooth lifting hinge shaft. This structure allows the tooth lifting connecting rod to better pull the tooth holder up and down.

[0009] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the feed dog has a clearance groove for avoiding curved sections, and the clearance groove is arranged along the front-to-back direction of the sewing machine. The feed dog and the slide bar rotate relative to each other; the clearance groove prevents the feed dog and the slide bar from jamming together, thus improving the stability of the motion device.

[0010] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the curved section protrudes towards the feed crank, and the opening of the curved section faces the lifting dog connecting rod. This structure makes reasonable use of the internal space of the sewing machine, allows for a rational arrangement of the curved section, and facilitates the installation of the slide bar.

[0011] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the height of the lifting rod is not less than the height of the curved section. This structure ensures that the feed dog is positioned appropriately.

[0012] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the motion device further includes a lower shaft, a lifting eccentric crank fixedly connected to the lower shaft, and a connecting crank fixedly connected to the right end of the lifting shaft. The lower shaft is located between the lower feed shaft and the lifting shaft. The outer end of the connecting crank has an arc-shaped groove. The outer end of the lifting eccentric crank is hinged to a rotating shaft. The rotating shaft passes through the groove and is locked with a nut to hinge the lifting eccentric crank to the connecting crank. The lower shaft can drive the feed dog to move up and down through the lifting eccentric crank, the connecting crank, the lifting shaft, the lifting crank, the lifting connecting rod, the feed dog bracket, and the slide rod. The slot is arc-shaped and elongated. The rotating shaft passes through the middle or both ends of the slot, changing the distance between the lifting tooth eccentric crank and the right end of the lifting tooth shaft, which is equivalent to changing the effective working length of the connecting crank. When this distance is large, the rotation amplitude of the lifting tooth shaft becomes smaller, and the up-and-down movement amplitude of the feeding tooth decreases, making the movement of the feeding tooth's approximately elliptical trajectory flatter. When this distance is small, the rotation amplitude of the lifting tooth shaft becomes larger, and the up-and-down movement amplitude of the feeding tooth increases, making the movement of the feeding tooth's approximately elliptical trajectory more circular, thus fine-tuning the movement trajectory of the feeding tooth. Moreover, the lower shaft is located between the lower feeding shaft and the lifting tooth shaft, making the motion device structure compact.

[0013] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the sewing machine also includes a base plate. A receiving groove is located at the edge of the center of the base plate, and the outer ends of the connecting crank and the eccentric crank for lifting the feed dog are both located within this receiving groove. The receiving groove's location at the edge of the base plate facilitates fine-tuning of the feed dog's movement trajectory by the operator.

[0014] In the aforementioned motion device for the feed tooth of a high-platform column sewing machine, an eccentric bushing is fitted on the left end of the lower feed shaft. The eccentric bushing has an opening that extends through it along its own axial direction. The top of the feed crank has a through hole through which the left end of the lower feed shaft passes. The top of the feed crank has a clamping slot that is axially arranged along the through hole and communicates with the through hole. The top of the feed crank has protruding flanges on both the upper and lower sides of the clamping slot. The two flanges are locked together by bolts. The eccentric bushing is inserted and fixed in the through hole. The eccentric bushings have different wall thicknesses. By rotating the eccentric bushings, the height of the rear end of the feed dog can be changed. When the thinner wall of the eccentric bushing faces upward, the height of the rear end of the feed dog is lower, and the rear end of the feed dog follows an elliptical trajectory downward. When the thicker wall of the eccentric bushing faces upward, the height of the rear end of the feed dog is higher, and the rear end of the feed dog follows an elliptical trajectory upward. At the same time, the lifting crank can rotate a certain angle relative to the lifting shaft and then be fixed, making the height of the front end of the feed dog adjustable. This allows the front end of the feed dog to rise or fall, thus fine-tuning the movement trajectory of the feed dog to adapt to different sewing materials. The design of open seams and clamping seams allows the eccentric bushing to be more tightly fixed on the lower feed shaft, improving the stability of the feed dog trajectory fine-tuning.

[0015] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the motion device further includes a feed eccentric crank fixedly connected to the lower shaft and a feed swing assembly disposed in the middle or at the right end of the lower feed shaft. The outer end of the feed eccentric crank is hinged to the feed swing assembly. The lower shaft can drive the feed dog to move back and forth through the feed eccentric crank, the feed swing assembly, the lower feed shaft, the feed crank, the feed dog holder, and the slide rod. This structure simplifies the back-and-forth movement of the feed dog driven by the lower shaft, occupies little installation space, and the feed swing assembly is a commonly used swing assembly in sewing machines, which is existing technology; its specific structure will not be described in detail.

[0016] In the aforementioned motion device for the feed dog of a high-platform sewing machine, the column has a mounting groove, the width of which is greater than the width of the slide rod. The slide rod is embedded in the mounting groove. A limiting piece is fixed to the top of the column, causing the top of the slide rod to rest against the bottom of the mounting groove. The bottom of the mounting groove has a sliding groove arranged vertically. A cuboid-shaped sliding block is hinged to the slide rod, the sliding block being embedded in the sliding groove and capable of sliding up and down along the sliding groove. This structure allows the slide rod to slide up and down relative to the column and swing back and forth, resulting in a simple structure.

[0017] Compared with the prior art, the motion device for the feed dog of a high-platform sewing machine provided by the present invention has the following advantages:

[0018] 1. The feed crank of this motion device extends downward, which is exactly the opposite of the upward extension of the feed crank in the prior art. That is, the direction in which the feed crank drives the toothed frame to move back and forth is opposite to that of the prior art. This can counteract the hinge reversal between the slide rod and the column, so that the sewing machine does not need to add an extra steering gear, making the motion device easy to install, reducing the failure rate, and improving the stability of the motion device.

[0019] 2. This motion device can adjust the swing amplitude of the lifting shaft by setting an arc-shaped groove at the outer end of the connecting crank. By setting an eccentric bushing, the height of the rear end of the feed dog can be changed, thereby changing the elliptical running trajectory of the feed dog to adapt to the sewing of different fabrics. Attached Figure Description

[0020] Figure 1 This is a structural diagram of the high-platform column sewing machine.

[0021] Figure 2 This is a schematic diagram of the overall structure of the motion device of the feeding toother from the left.

[0022] Figure 3 This is a right-side overall structural diagram of the motion device of the feeding toother.

[0023] Figure 4 This is a schematic diagram of the structure of the feed tooth's moving device tooth frame.

[0024] Figure 5 This is a high-platform column sewing machine. Figure 1 A magnified view of region A in the middle.

[0025] Figure 6 This is a schematic diagram of the overall structure of the eccentric bushing of the motion device of the feeding toother.

[0026] In the diagram, 1. Lower feed shaft; 2. Tooth lifting shaft; 3. Tooth bracket; 31. Clearance groove; 32. Hinge groove; 4. Slide rod; 41. Bending section; 5. Tooth lifting crank; 6. Column; 61. Mounting groove; 62. Sliding groove; 7. Feed tooth; 8. Feeding crank; 81. Feeding groove; 82. Through hole; 83. Clamping seam; 84. Protruding edge; 9. Tooth lifting connecting rod; 10. Feeding hinge shaft; 11. Tooth lifting hinge shaft; 12. Lower shaft; 13. Tooth lifting eccentric crank; 14. Connecting crank; 141. Strip groove; 15. Rotating shaft; 16. Base plate; 161. Receiving groove; 17. Eccentric bushing; 171. Opening seam; 18. Feeding eccentric crank; 19. Feeding swing assembly; 20. Limiting plate; 21. Sliding block. Detailed Implementation

[0027] 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.

[0028] like Figure 1 As shown, the high-platform sewing machine 6 includes a base plate 16 and a motion device, which is disposed in the base plate 16. Figure 2 , Figure 3 As shown, the motion device of the feed tooth 7 of the high platform column 6 sewing machine includes a lower feed shaft 1, a tooth lifting shaft 2, a tooth frame 3, a slide bar 4, a tooth lifting crank 5, a feed crank 8, a tooth lifting connecting rod 9, a lower shaft 12, a tooth lifting eccentric crank 13, a connecting crank 14, an eccentric bushing 17, a feed eccentric crank 18, and a feed swing assembly 19.

[0029] The column 6 is fixed to the base plate 16. The slide rod 4 is installed in the column 6. The top of the slide rod 4 is fixed to the feeding tooth 7. The bottom of the slide rod 4 is hinged to the middle of the tooth frame 3. The slide rod 4 can slide up and down and swing back and forth relative to the column 6. Specifically, the column 6 has a mounting groove 61. The width of the mounting groove 61 is greater than the width of the slide rod 4. The slide rod 4 is embedded in the mounting groove 61. The top of the column 6 is fixed to the limiting piece 20. The limiting piece 20 makes the top of the slide rod 4 abut against the bottom of the mounting groove 61. The bottom of the mounting groove 61 has a sliding groove 62 arranged vertically. A cuboid sliding block 21 is hinged to the slide rod 4. The sliding block 21 is embedded in the sliding groove 62 and can slide up and down along the sliding groove 62.

[0030] The lower shaft 12 is located between the lower feed shaft 1 and the lifting shaft 2. A lifting eccentric crank 13 and a feeding eccentric crank 18 are fixedly connected to the lower shaft 12. The lifting eccentric crank 13 is located to the left of the feeding eccentric crank 18, and there is a gap between the lifting eccentric crank 13 and the feeding eccentric crank 18. Figure 4 As shown, the dental frame 3 is long and narrow, with both the front and rear ends of the dental frame 3 curving upwards.

[0031] A lifting crank 5 is fixedly connected to the left end of the lifting shaft 2, and a connecting crank 14 is fixedly connected to the right end of the lifting shaft 2. The outer end of the connecting crank 14 has an arc-shaped groove 141. A rotating shaft 15 is hinged to the outer end of the lifting eccentric crank 13. The rotating shaft 15 passes through the groove 141 and is locked with a nut to hinge the lifting eccentric crank 13 to the connecting crank 14. Figure 5 As shown, the bottom plate 16 has a receiving groove 161 at the edge of the middle part, and the outer ends of the connecting crank 14 and the tooth-lifting eccentric crank 13 are both located in the receiving groove 161. The tooth-lifting connecting rod 9 is long and narrow. The top of the tooth-lifting connecting rod 9 is hinged to the tooth-lifting crank 5. The front end of the tooth frame 3 has a hinge groove 32. The bottom of the tooth-lifting connecting rod 9 is embedded in the hinge groove 32 and is hinged to the tooth frame 3 through the tooth-lifting hinge shaft 11. The lower shaft 12 can drive the feeding tooth 7 to move up and down through the tooth-lifting eccentric crank 13, the connecting crank 14, the tooth-lifting shaft 2, the tooth-lifting crank 5, the tooth-lifting connecting rod 9, the tooth frame 3, and the slide rod 4.

[0032] An eccentric bushing 17 is fitted onto the left end of the lower feed shaft 1, such as... Figure 6 As shown, the eccentric bushing 17 has an opening slit 171 extending along its own axial direction. The top of the feeding crank 8 has a through hole 82 for the left end of the lower feeding shaft 1 to pass through. The top of the feeding crank 8 has a clamping slit 83 arranged axially along the through hole 82 and communicating with the through hole 82. The top of the feeding crank 8 has protruding flanges 84 on both the upper and lower sides of the clamping slit 83. The two flanges 84 are locked by bolts. The eccentric bushing 17 is inserted and fixed in the through hole 82. The bottom of the feeding crank 8 has a feeding groove 81. The rear end of the toothed bracket 3 is embedded in the feeding groove 81 and is hinged to the feeding crank 8 through the feeding hinge shaft 10. In this embodiment, a feeding swing assembly 19 is provided in the middle of the lower feeding shaft 1. The outer end of the feeding eccentric crank 18 is hinged to the feeding swing assembly 19. In actual production, the feeding swing assembly 19 can be provided at the right end of the lower feeding shaft 1. The lower shaft 12 can drive the feeding tooth 7 to move back and forth through the feeding eccentric crank 18, the feeding swing assembly 19, the lower feeding shaft 1, the feeding crank 8, the tooth frame 3 and the slide bar 4.

[0033] The bottom of the slide bar 4 has an arc-shaped curved section 41 that protrudes towards the feed crank 8. The opening of the curved section 41 faces the lifting tooth connecting rod 9, and the curved section 41 forms a clearance space for avoiding the rotary hook base. The tooth holder 3 has a clearance groove 31 for avoiding the curved section 41, and the clearance groove 31 is arranged along the front-back direction of the sewing machine. The height of the lifting tooth connecting rod 9 is not less than the height of the curved section 41.

[0034] The sewing machine has a built-in motor to drive the lower shaft 12 to rotate. During operation, the motor drives the lower shaft 12 to rotate. The rotation of the lower shaft 12 drives the feed eccentric crank 18, the feed swing assembly 19, the lower feed shaft 1, and the feed crank 8 to move the feed dog 3 back and forth. At the same time, the rotation of the lower shaft 12 drives the feed dog 3 to move up and down through the feed dog lifting eccentric crank 13, the connecting crank 14, the feed dog lifting shaft 2, the feed dog lifting crank 5, and the feed dog lifting connecting rod 9. The combination of the two movements allows the slide bar 4 to slide up and down and swing back and forth relative to the column 6, so that the feed dog 7 at the top of the slide bar 4 produces an approximately elliptical motion trajectory, thereby feeding the fabric.

[0035] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention 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 the invention or exceeding the scope defined by the appended claims.

[0036] Although this document frequently uses terms such as lower feed shaft 1, lifting tooth shaft 2, tooth holder 3, clearance groove 31, hinge groove 32, slide rod 4, bent section 41, lifting tooth crank 5, column 6, mounting groove 61, sliding groove 62, feed tooth 7, feed crank 8, feed groove 81, through hole 82, clamping slot 83, raised edge 84, lifting tooth connecting rod 9, feed hinge shaft 10, lifting tooth hinge shaft 11, lower shaft 12, lifting tooth eccentric crank 13, connecting crank 14, strip groove 141, rotating shaft 15, base plate 16, receiving groove 161, eccentric bushing 17, opening slot 171, feed eccentric crank 18, feed swing assembly 19, limiting piece 20, and sliding block 21, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A motion device for the feed dog of a high-platform sewing machine, comprising a lower feed shaft (1), a lifting shaft (2), a feed dog frame (3), and a slide rod (4), wherein the left end of the lifting shaft (2) is fixedly connected to a lifting crank (5), the slide rod (4) is disposed in the column (6), and the slide rod (4) can slide up and down and swing back and forth relative to the column (6), the top of the slide rod (4) is fixedly connected to a feed dog (7), and the bottom of the slide rod (4) is hinged to the middle part of the feed dog frame (3), characterized in that, The motion device also includes a feeding crank (8) and a long strip-shaped lifting connecting rod (9). The feeding crank (8) extends downward and its top is fixedly connected to the left end of the lower feeding shaft (1). The bottom of the feeding crank (8) is hinged to the rear end of the tooth frame (3). The top of the lifting connecting rod (9) is hinged to the lifting crank (5), and the bottom of the lifting connecting rod (9) is hinged to the front end of the tooth frame (3). The bottom of the slide rod (4) has an arc-shaped curved section (41), which forms a clearance space for avoiding the rotary shuttle base.

2. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, characterized in that, The tooth frame (3) is long and narrow, with both ends of the tooth frame (3) pointing upwards. The bottom of the feeding crank (8) has a feeding groove (81). The rear end of the tooth frame (3) is embedded in the feeding groove (81) and is hinged to the feeding crank (8) through the feeding hinge shaft (10). The front end of the tooth frame (3) has a hinge groove (32). The bottom of the tooth lifting connecting rod (9) is embedded in the hinge groove (32) and is hinged to the tooth frame (3) through the tooth lifting hinge shaft (11).

3. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, characterized in that, The dental frame (3) has a clearance groove (31) for avoiding the curved section (41), the clearance groove (31) being arranged along the front-back direction of the sewing machine.

4. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, 2, or 3, characterized in that, The curved section (41) protrudes toward the feed crank (8), and the opening of the curved section (41) faces the lifting connecting rod (9).

5. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, 2, or 3, characterized in that, The height of the tooth-lifting link (9) is not less than the height of the curved section (41).

6. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, 2, or 3, characterized in that, The motion device also includes a lower shaft (12), a tooth-lifting eccentric crank (13) fixed on the lower shaft (12), and a connecting crank (14) fixed on the right end of the tooth-lifting shaft (2). The lower shaft (12) is located between the lower feed shaft (1) and the tooth-lifting shaft (2). The outer end of the connecting crank (14) has an arc-shaped groove (141). The outer end of the tooth-lifting eccentric crank (13) is hinged to a rotating shaft (15). The rotating shaft (15) passes through the groove (141) and is locked by a nut to make the tooth-lifting eccentric crank (13) and the connecting crank (14) hinged. The lower shaft (12) can drive the feed tooth (7) to move up and down through the tooth-lifting eccentric crank (13), the connecting crank (14), the tooth-lifting shaft (2), the tooth-lifting crank (5), the tooth-lifting connecting rod (9), the tooth frame (3), and the slide rod (4).

7. The motion device for the feed dog of a high-platform column sewing machine according to claim 6, characterized in that, The sewing machine also includes a base plate (16), which has a receiving groove (161) at the edge of the middle part of the base plate (16), and the outer ends of the connecting crank (14) and the lifting tooth eccentric crank (13) are both located in the receiving groove (161).

8. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, 2, or 3, characterized in that, An eccentric bushing (17) is fitted on the left end of the lower feed shaft (1). The eccentric bushing (17) has an opening (171) that runs through it along its own axial direction. The top of the feed crank (8) has a through hole (82) through which the left end of the lower feed shaft (1) passes. The top of the feed crank (8) has a clamping slot (83) that runs along the axial direction of the through hole (82) and is connected to the through hole (82). The top of the feed crank (8) has protruding flanges (84) on both the upper and lower sides of the clamping slot (83). The two flanges (84) are locked by bolts. The eccentric bushing (17) is inserted and fixed in the through hole (82).

9. The motion device for the feed dog of a high-platform column sewing machine according to claim 6, characterized in that, The motion device also includes a feeding eccentric crank (18) fixed to the lower shaft (12) and a feeding swing assembly (19) disposed in the middle or right end of the lower feeding shaft (1). The outer end of the feeding eccentric crank (18) is hinged to the feeding swing assembly (19). The lower shaft (12) can drive the feeding tooth (7) to move back and forth through the feeding eccentric crank (18), the feeding swing assembly (19), the lower feeding shaft (1), the feeding crank (8), the tooth frame (3) and the slide rod (4).

10. The motion device for the feed dog of a high-platform column sewing machine according to claim 1, 2, or 3, characterized in that, The column (6) has a mounting groove (61) with a width greater than that of the slide rod (4). The slide rod (4) is embedded in the mounting groove (61). A limiting piece (20) is fixedly connected to the top of the column (6). The limiting piece (20) causes the top of the slide rod (4) to abut against the bottom of the mounting groove (61). The bottom of the mounting groove (61) has a sliding groove (62) arranged vertically. A cuboid sliding block (21) is hinged to the slide rod (4). The sliding block (21) is embedded in the sliding groove (62) and can slide up and down along the sliding groove (62).

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