CN210975087U

CN210975087U - Sewing machine

Info

Publication number: CN210975087U
Application number: CN201920937907.9U
Authority: CN
Inventors: 嵇建国; 陈满良; 黄大好
Original assignee: Anhui Jieyu Shoemaking Machinery Technology Co ltd
Current assignee: Anhui Jieyu Shoemaking Machinery Technology Co ltd
Priority date: 2019-06-20
Filing date: 2019-06-20
Publication date: 2020-07-10
Anticipated expiration: 2029-06-20

Abstract

The utility model discloses a sewing machine, which comprises a mechanical backstitch mechanism, a knob needle pitch adjusting mechanism and a simple direct-drive driving mechanism, wherein the knob needle pitch adjusting mechanism is arranged on the mechanical backstitch mechanism, and the mechanical backstitch mechanism and the simple direct-drive driving mechanism are mutually fixed; the mechanical backstitch mechanism saves an upper backstitch electromagnet, a lower backstitch electromagnet and a needle swing electromagnet, can be more energy-saving and durable, and can reduce the power consumption and the cost; the design of the through shaft is adopted, the concentricity of the driving shaft and the upper shaft is better, and the transmission is more flexible and stable; the stitch length is adjusted in a knob mode, so that the stitch length is adjusted more conveniently, and the needed stitch length can be adjusted without two-hand operation; compared with a three-step automatic and three-step roller car, the automatic and three-step roller car is simple and low in price, and can meet the requirements of conventional use; compared with the existing high trolley, the high trolley is convenient to use and install, saves energy, reduces consumption and is simple, convenient and quick to operate.

Description

Sewing machine

Technical Field

The utility model relates to a textile sewing machine technical field specifically is a sewing machine.

Background

Existing market roller carts are mainly classified into two categories: the high-end type mainly comprises: servo direct drive roller cars, three automatic roller cars, and three step-by-step roller cars without batch application; the machine has stable performance, high efficiency and high price, and is mainly used for domestic high-end shoe-making enterprises; the low-end models mainly include: the traditional high trolley adopts a clutch motor, so that the cost is high, and the motor is complex and complicated to prepare and install; the machine has high energy consumption and low efficiency, and is mainly used for domestic workshops, small enterprises and southeast Asia national shoe-making enterprises.

The low-end models which are complicated to install, consume energy and are not environment-friendly can gradually exit the market, while the high-end models which are energy-saving and efficient have higher price and are difficult to be accepted by the low-end market at home and abroad, so that a model is necessary to be developed: the low-end model which is energy-saving, low in consumption, convenient to operate, stable in performance and proper in price meets the requirement of equipment upgrading in the low-end market; in order to improve the low working efficiency of small enterprises and foreign low-end markets and save energy consumption and reduce use cost for the society, the appearance of the simple direct-drive roller car can greatly improve the low-end field of the industry and promote the healthier development of the industry, and the market prospect is wide.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a sewing machine to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: a sewing machine comprises a mechanical backstitch mechanism, a knob needle gauge adjusting mechanism and a simple direct-drive driving mechanism, wherein the knob needle gauge adjusting mechanism is arranged on the mechanical backstitch mechanism, and the mechanical backstitch mechanism and the simple direct-drive driving mechanism are fixed with each other;

the mechanical backstitch mechanism comprises a backstitch manual wrench assembly, a first backstitch crank, a first backstitch connecting rod and a crank mounting seat, wherein the backstitch manual wrench assembly and the first backstitch crank are connected in a matched mode through gears, and the first backstitch connecting rod is arranged on the first backstitch crank and connected with the crank mounting seat; the crank mounting seat is connected with a driving lever through a pull rod, a lower feeding one-way bearing driving assembly is mounted on the driving lever, a reversing shaft is arranged on the lower feeding one-way bearing driving assembly, and a front seam gear and a back seam gear are arranged on the reversing shaft; a driven gear is arranged above the reversing shaft and is connected with a lower feeding gear through a lower feeding transmission assembly;

the needle pitch adjusting mechanism comprises a needle pitch knob component and a needle pitch adjusting cam, the needle pitch knob component is installed on the needle pitch adjusting cam, the needle pitch adjusting cam is connected with a needle pitch adjusting swing rod component through a needle pitch adjusting pull rod, the needle pitch cam component is installed on the needle pitch adjusting swing rod component, a lower feeding shaft is installed on the needle pitch adjusting swing rod component, the lower feeding shaft is connected with a first universal connecting rod component through a lower feeding shaft driving component, and the first universal connecting rod component is connected with a lower feeding one-way bearing driving component;

the simple direct-drive driving mechanism comprises a motor assembly and an electric control assembly, the electric control assembly is arranged on the box body, the motor assembly is fixed in the box body, and the motor assembly is electrically connected with the electric control assembly; the needle bar driving connecting rod assembly is arranged on the main shaft assembly, and the needle bar assembly is mounted on the needle bar driving connecting rod assembly.

Preferably, a first gear assembly is arranged on the backstitch manual wrench assembly, a second gear assembly is arranged on the first backstitch crank, the first gear assembly and the second gear assembly are mutually meshed, and the first backstitch connecting rod and the rotating shaft of the second gear assembly are mutually fixed; the crank mounting seat is connected with the first backstitch connecting rod and the pull rod through the first backstitch transmission crank assembly and the second backstitch transmission crank assembly respectively.

Preferably, a second backstitch crank is arranged on a rotating shaft of the second gear assembly, the second backstitch crank is connected with an upper backstitch crank through an upper backstitch connecting rod, the upper backstitch crank is arranged on a backstitch shaft, a second gear is arranged on the backstitch shaft, the second gear is meshed with the first gear, the first gear is connected with a connecting rod cam through a rotating shaft, a jacking block is arranged on the connecting rod cam, a universal connecting sleeve is fixed on the jacking block, a feeding clutch is fixedly connected with the universal connecting sleeve, a lower feeding clutch is arranged on the upper feeding clutch in a matched mode, an upper feeding wheel is arranged on the lower feeding clutch, and the lower feeding gear is matched with the upper feeding wheel.

Preferably, the needle bar transmission connecting rod assembly is transversely provided with a needle bar seat assembly, the needle bar seat assembly is connected with a needle pitch adjusting connecting rod through a needle swinging crank, the needle pitch adjusting connecting rod is connected with a first needle pitch adjusting crank, the first needle pitch adjusting crank is arranged on a lower feeding shaft, and the lower feeding shaft is connected with the needle pitch adjusting swing rod assembly through a second needle pitch adjusting crank.

Preferably, the needle bar seat assembly is connected with an upper feeding shaft through a swinging needle driving connecting rod, one end of the upper feeding shaft is provided with an upper universal connecting rod assembly, the second universal connecting rod assembly is provided with an upper feeding one-way bearing driving assembly in a matching manner, and the upper feeding one-way bearing driving assembly is arranged on an upper feeding clutch; the backstitch shaft is provided with a swing needle reversing crank assembly, and the swing needle reversing crank assembly is matched with the swing needle driving connecting rod.

Preferably, a stitch length adjusting crank assembly is arranged at the top end of the stitch length adjusting pull rod, a stitch length adjusting ball is arranged on the stitch length adjusting crank assembly, and the stitch length adjusting ball is matched with the stitch length adjusting cam.

Preferably, the needle pitch adjusting swing rod assembly comprises a machine pin, a swinging swing seat and a long pin, and the machine pin and the long pin are respectively positioned on two sides of the swinging swing seat; the long pin is provided with a long crank connecting rod and a short crank connecting rod, the long crank connecting rod is connected with a second needle pitch adjusting crank and is fixed through a second short crank pin; the needle pitch cam assembly is arranged on the long pin and is positioned between the long crank connecting rod and the short crank connecting rod; the needle pitch adjusting pull rod is fixed on the swing seat through a first short crank pin, a cardan shaft is arranged on the needle pitch cam component, and a third short crank pin is arranged on the short crank connecting rod.

Preferably, a first bearing and a second bearing are respectively arranged at two ends of the one-way bearing driving assembly, a connecting shaft is fixed on the front seam gear, the connecting shaft is fixed on a bushing in the bearing through a third transmission pin, and the bushing in the bearing is arranged on the one-way bearing driving assembly; the first bearing is provided with a gear shaft connecting block, and the gear shaft connecting block is provided with a screw.

Preferably, the middle casing of the bearing is arranged on a driving lever fixing seat, the driving lever fixing seat is fixed with the driving lever through a supporting pin, and the gear shaft connecting block is fixed with the driving lever through a first driving pin and a second driving pin.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the mechanical backstitch mechanism saves an upper backstitch electromagnet, a lower backstitch electromagnet and a needle swing electromagnet, can be more energy-saving and durable, and can reduce the power consumption and the cost;

2. the design of the through shaft is adopted, the concentricity of the driving shaft and the upper shaft is better, and the transmission is more flexible and stable;

3. the stitch length is adjusted in a knob mode, so that the stitch length is adjusted more conveniently, and the needed stitch length can be adjusted without two-hand operation;

4. compared with a three-step automatic and three-step roller car, the automatic and three-step roller car is simple and low in price, and can meet the requirements of conventional use;

5. compared with the existing high trolley, the high trolley is convenient to use and install, saves energy, reduces consumption and is simple, convenient and quick to operate.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of a mechanical backstitch mechanism of the present invention;

FIG. 3 is an enlarged view taken at A in FIG. 2;

FIG. 4 is a schematic structural view of a knob needle pitch adjusting mechanism of the present invention;

FIG. 5 is an enlarged view of FIG. 4 at B;

fig. 6 is a schematic structural view of the simple direct-drive driving mechanism of the present invention;

FIG. 7 is a schematic structural view of a needle pitch adjusting swing link assembly of the present invention;

FIG. 8 is a schematic view of the mechanical lower backstitch structure of the present invention;

reference numbers in the figures: 1. a first universal linkage assembly; 2. a drive lever; 3. a lower feeding one-way bearing driving component; 4. a spur gear; 5. a reversing shaft; 6. a backstitch gear; 7. a pull rod; 8. a needle pitch adjusting swing rod assembly; 8-1, a frame pin; 8-2, swinging the swing seat; 8-3, long pin; 8-4, a crank long connecting rod; 8-5, a first crank short pin; 8-6, a second short crank pin; 8-7, a third short crank pin; 8-8, a crank short connecting rod; 9. A needle pitch adjusting pull rod; 10. a needle pitch cam assembly; 11 a first backstitch drive crank assembly; 12. a crank mounting base; 13. a second backstitch drive crank assembly; 14 a first backstitch link; 15. a backstitch hand wrench assembly; 16. a first gear assembly; 17. a second gear assembly; 18. a gauge knob assembly; 19 needle pitch adjusting cams; 20. a needle pitch adjusting ball; 21 a stitch length adjusting crank assembly; 22. a first backstitch crank; 22-1, a second backstitch crank; 23. a needle pitch adjusting link; 24. a first stitch length adjusting crank; 25. a second stitch length adjusting crank; 26. a lower feed shaft; 27. a lower feeding driven gear; 28. a lower feeding transmission crank; 29. a lower feed drive assembly; 30. a lower feeding gear; 31. an upper feeding wheel; 32. an upper feeding and lower clutch; 33. An upper feeding and upper clutch; 34. an upper feeding one-way bearing driving component; 35. a second universal link assembly; 36. a link cam; 37. a top block; 38. a universal connecting sleeve; 39. a first gear; 40. a second gear; 41. a needle bar assembly; 42. a needle bar holder assembly; 43. a needle bar transmission connecting rod assembly; 44. an upper shaft assembly; 45. a backstitch shaft; 46. an upper feeding shaft; 47. a needle swinging crank; 48. a needle swinging driving connecting rod; 49. a swing needle reversing crank assembly; 50. an upper backstitch connecting rod; 51. an upper backstitch crank; 52. a motor assembly; 53 an electronic control assembly; 54. a cardan shaft; 55. a screw; 56. a gear shaft connecting block; 57. a first drive pin; 58. a first bearing; 59. a second bearing; 60. sleeving a middle bushing in the bearing; 61. a second drive pin; 62. a driving lever fixing seat; 63. a support pin; 64. a third drive pin.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "vertical", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Referring to fig. 1-8, the present invention provides a technical solution: a sewing machine comprises a mechanical backstitch mechanism, a knob needle gauge adjusting mechanism and a simple direct-drive driving mechanism, wherein the knob needle gauge adjusting mechanism is arranged on the mechanical backstitch mechanism, and the mechanical backstitch mechanism and the simple direct-drive driving mechanism are fixed with each other;

the mechanical backstitch mechanism comprises a backstitch manual wrench assembly 15, a first backstitch crank 22, a first backstitch connecting rod 14 and a crank mounting seat 12, wherein the backstitch manual wrench assembly 15 and the first backstitch crank 22 are connected in a matched mode through gears, and the first backstitch connecting rod 14 is arranged on the first backstitch crank 22 and connected with the crank mounting seat 12; the crank mounting seat 12 is connected with a driving lever 2 through a pull rod 7, a lower feeding one-way bearing driving assembly 3 is mounted on the driving lever 2, a reversing shaft 5 is arranged on the lower feeding one-way bearing driving assembly 3, and a front seam gear 4 and a back seam gear 6 are arranged on the reversing shaft 5; a driven gear 27 is arranged above the reversing shaft 5, and the driven gear 27 is connected with a lower feeding gear 30 through a lower feeding transmission component 29;

the knob needle distance adjusting mechanism comprises a needle distance knob component 18 and a needle distance adjusting cam 19, the needle distance knob component 18 is installed on the needle distance adjusting cam 19, the needle distance adjusting cam 19 is connected with a needle distance adjusting swing rod component 8 through a needle distance adjusting pull rod 9, the needle distance cam component 10 is installed on the needle distance adjusting swing rod component 8, a lower feeding shaft 26 is installed on the needle distance adjusting swing rod component 8, the lower feeding shaft 26 is connected with a first universal connecting rod component 1 through a lower feeding shaft driving component 28, and the first universal connecting rod component 1 is connected with a lower feeding one-way bearing driving component 3;

the simple direct-drive driving mechanism comprises a motor assembly 52 and an electric control assembly 53, the electric control assembly 53 is arranged on the box body, the motor assembly 52 is fixed in the box body, and the motor assembly 52 is electrically connected with the electric control assembly 53; the motor assembly 52 is fixed with the spindle assembly 44, the spindle assembly 44 is provided with a needle rod transmission connecting rod assembly 43, and the needle rod assembly 41 is mounted on the needle rod transmission connecting rod assembly 43.

Further, a first gear assembly 16 is arranged on the backstitch manual wrench assembly 15, a second gear assembly 17 is arranged on the first backstitch crank 22, the first gear assembly 16 and the second gear assembly 17 are meshed with each other, and rotating shafts of the first backstitch connecting rod 14 and the second gear assembly 17 are fixed with each other; the crank mounting base 12 is respectively connected with the first backstitch connecting rod 14 and the pull rod 7 through a first backstitch transmission crank component 11 and a second backstitch transmission crank component 13.

Further, a second backstitch crank 22-1 is arranged on a rotating shaft of the second gear assembly 17, the second backstitch crank 22-1 is connected with an upper backstitch crank 51 through an upper backstitch connecting rod 50, the upper backstitch crank 51 is arranged on a backstitch shaft 45, a second gear 40 is arranged on the backstitch shaft 45, the second gear 40 is meshed with the first gear 39, the first gear 39 is connected with a connecting rod cam 36 through a rotating shaft, a top block 37 is arranged on the connecting rod cam 36, a universal connecting sleeve 38 is fixed on the top block 37, an upper feeding clutch 33 is fixedly connected with the universal connecting sleeve 38, a lower feeding clutch 32 is arranged on the upper feeding clutch 33 in a matched mode, an upper feeding wheel 31 is arranged on the lower feeding clutch 32, and the lower feeding gear 30 is matched with the upper feeding wheel 31.

Further, the needle bar transmission connecting rod assembly 43 is transversely provided with a needle bar seat assembly 42, the needle bar seat assembly 42 is connected with a needle pitch adjusting connecting rod 23 through a needle swinging crank 47, the needle pitch adjusting connecting rod 23 is connected with a first needle pitch adjusting crank 24, the first needle pitch adjusting crank 24 is arranged on the lower feeding shaft 26, and the lower feeding shaft 26 is connected with the needle pitch adjusting swing rod assembly 8 through a second needle pitch adjusting crank 25.

Further, the needle bar seat assembly 42 is connected with an upper feeding shaft 46 through a needle swinging driving connecting rod 48, one end of the upper feeding shaft 46 is provided with an upper second universal connecting rod assembly 35, the upper feeding one-way bearing driving assembly 34 is arranged on the second universal connecting rod assembly 35 in a matching way, and the upper feeding one-way bearing driving assembly 34 is arranged on the upper feeding clutch 33; the backstitch shaft 45 is provided with a swing needle reversing crank assembly 49, and the swing needle reversing crank assembly 49 is matched with the swing needle driving connecting rod 48.

Furthermore, a needle pitch adjusting crank assembly 21 is arranged at the top end of the needle pitch adjusting pull rod 9, a needle pitch adjusting ball 20 is arranged on the needle pitch adjusting crank assembly 21, and the needle pitch adjusting ball 20 is matched with the needle pitch adjusting cam 19.

Further, the needle pitch adjusting swing rod assembly 8 comprises a machine pin 8-1, a swinging swing seat 8-2 and a long pin 8-3, wherein the machine pin 8-1 and the long pin 8-3 are respectively positioned on two sides of the swinging swing seat 8-2; a crank long connecting rod 8-4 and a crank short connecting rod 8-8 are arranged on the long pin 8-3, and the crank long connecting rod 8-4 is connected with a second needle pitch adjusting crank 25 and is fixed through a second crank short pin 8-6; the needle pitch cam component 10 is arranged on the long pin 8-3 and is positioned between the crank long connecting rod 8-4 and the crank short connecting rod 8-8; the needle pitch adjusting pull rod 9 is fixed on the swing seat 8-2 through a first short crank pin 8-5, a universal shaft 54 is arranged on the needle pitch cam component 10, and a third short crank pin 8-7 is arranged on the short crank connecting rod 8-8.

Furthermore, a first bearing 58 and a second bearing 59 are respectively arranged at two ends of the one-way bearing driving component 3, a connecting shaft is fixed on the front seam gear 4, the connecting shaft is fixed on a bearing bush 60 in the bearing through a third transmission pin 64, and the bearing bush 60 in the bearing bush is arranged on the one-way bearing driving component 3; the first bearing 58 is provided with a gear coupling block 56, and the gear coupling block 56 is provided with a screw 55.

Further, the middle casing 60 of the pellin is arranged on a driving lever fixing seat 62, the driving lever fixing seat 62 is fixed with the driving lever 2 through a supporting pin 63, and the gear shaft connecting block 56 is fixed with the driving lever 2 through a first driving pin 57 and a second driving pin 61.

The working principle is as follows:

the working process of the mechanical backstitch mechanism is as follows: the first gear assembly 16 is driven to drive the second gear assembly 17 by pressing down the backstitch manual wrench assembly 15, the first backstitch connecting rod 14 is driven to rotate the first backstitch transmission crank assembly 11 and the second backstitch transmission crank assembly 13 around the crank mounting seat 12 by the backstitch crank 22 fixed on the shaft of the gear assembly 17, the driving lever 2 is driven to rotate by the pulling pull rod 7, the forward-looking shaft 5 is pulled to drive the forward-looking gear 4 fixed on the forward-looking shaft 5 and the backstitch gear 6 to move leftwards, so that the lower feeding driven gear 27 is meshed with the backstitch gear 6 instead of being meshed with the forward-looking gear 4, and the lower feeding transmission assembly 29 drives the lower feeding gear 30 to rotate backwards to realize backstitch.

When the backstitch manual wrench assembly 15 is pressed down and the first gear assembly 16 is driven to drive the second gear assembly 17, the backstitch crank 22-1 fixed on the shaft of the gear assembly 17 drives the backstitch crank 51 on the upper backstitch connecting rod 50 to rotate, so that the backstitch shaft 45 rotates to drive the second gear 40 and the first gear 39 to rotate, the connecting rod cam 36 fixed on the shaft of the first gear 39 rotates to jack the jacking block 37, the universal connecting sleeve 38 fixed on the jacking block 37 drives the upper feeding clutch 33 to ascend and separate from the lower feeding clutch 32, the driving force of the upper feeding wheel 31 and the driving force of the upper feeding one-way bearing driving assembly are separated, the upper feeding wheel becomes a free wheel and rotates along with the movement of the sewing materials, the movement of the sewing materials cannot be hindered, and the upper layer and the lower layer of the sewing materials are staggered.

The swinging needle reversing crank assembly 49 fixed on the backstitch shaft 45 rotates to change the position of the swinging needle driving connecting rod 48, so that the swinging direction of the swinging needle crank 47 is changed, the shaft rotating direction of the needle bar seat assembly 42 is changed, and finally the needle bar assembly 41 moves from back to front from front to back from the beginning to ensure that the needle feeding direction is consistent with the feeding direction of the feeding wheel.

The working process of the needle pitch adjusting mechanism with the knob is as follows: the needle pitch knob assembly 18 is rotated to drive the needle pitch adjusting cam 19 to rotate, the needle pitch adjusting pull rod 9 is pulled to change the position of the internal part of the needle pitch adjusting swing rod assembly 8, the same motion displacement of the needle pitch cam assembly 10 is enabled to be transmitted to the second needle pitch adjusting crank 25 to form different swing angles, the swing angles of the lower feeding shaft 26 and the lower feeding shaft driving assembly 28 are changed accordingly, the universal connecting rod assembly 1 drives the lower feeding one-way bearing driving assembly 3 to have different rotation angles, the forward sewing gear 4 and the reverse sewing gear 6 are driven to change the rotation speed, and finally the rotation speed of the lower feeding gear 30 is changed, so that the sewing needle pitch is changed.

The change of the rotation angle of the lower feeding shaft 26 enables the first pitch adjusting crank 24 to change the rotation angle, the upper feeding shaft 46 is driven by the pitch adjusting connecting rod 23 to change the rotation angle, and the upper feeding one-way bearing driving assembly 34 is driven by the upper universal connecting rod assembly 35 to rotate so as to drive the upper feeding wheel 31 to rotate for feeding.

The simple direct-drive driving mechanism has the working process that: the motor assembly 52 is directly connected with the main shaft assembly 44, and drives the needle rod assembly 41 to move up and down through the needle rod transmission connecting rod assembly 43, so that the needle penetrates through the sewing material to realize sewing.

The motor assembly 52 is controlled by an electric control assembly 53 mounted on the housing; various sewing parameters such as the motor running speed, the needle stopping angle, the soft starting needle number, the braking needle number and the like can be set through the operation box of the electric control component 53.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A sewing machine characterized by: the simple direct-drive backstitch mechanism is characterized by comprising a mechanical backstitch mechanism, a knob needle pitch adjusting mechanism and a simple direct-drive driving mechanism, wherein the knob needle pitch adjusting mechanism is arranged on the mechanical backstitch mechanism, and the mechanical backstitch mechanism and the simple direct-drive driving mechanism are fixed with each other;

the mechanical backstitch mechanism comprises a backstitch manual wrench assembly (15), a first backstitch crank (22), a first backstitch connecting rod (14) and a crank mounting seat (12), wherein the backstitch manual wrench assembly (15) and the first backstitch crank (22) are connected in a matched mode through gears, and the first backstitch connecting rod (14) is arranged on the first backstitch crank (22) and connected with the crank mounting seat (12); the crank mounting seat (12) is connected with a driving lever (2) through a pull rod (7), a lower feeding one-way bearing driving assembly (3) is mounted on the driving lever (2), the reversing shaft (5) is arranged on the lower feeding one-way bearing driving assembly (3), and the front seam gear (4) and the back seam gear (6) are arranged on the reversing shaft (5); a driven gear (27) is arranged above the reversing shaft (5), and the driven gear (27) is connected with a lower feeding gear (30) through a lower feeding transmission assembly (29);

the needle pitch adjusting mechanism comprises a needle pitch knob assembly (18) and a needle pitch adjusting cam (19), the needle pitch knob assembly (18) is installed on the needle pitch adjusting cam (19), the needle pitch adjusting cam (19) is connected with a needle pitch adjusting swing rod assembly (8) through a needle pitch adjusting pull rod (9), a needle pitch cam assembly (10) is installed on the needle pitch adjusting swing rod assembly (8), a lower feeding shaft (26) is installed on the needle pitch adjusting swing rod assembly (8), the lower feeding shaft (26) is connected with a first universal connecting rod assembly (1) through a lower feeding shaft driving assembly (28), and the first universal connecting rod assembly (1) is connected with a lower feeding one-way bearing driving assembly (3);

the simple direct-drive driving mechanism comprises a motor assembly (52) and an electric control assembly (53), the electric control assembly (53) is arranged on the box body, the motor assembly (52) is fixed in the box body, and the motor assembly (52) is electrically connected with the electric control assembly (53); the needle bar driving mechanism is characterized in that a main shaft assembly (44) is fixed on the motor assembly (52), a needle bar driving connecting rod assembly (43) is arranged on the main shaft assembly (44), and a needle bar assembly (41) is installed on the needle bar driving connecting rod assembly (43).

2. A sewing machine according to claim 1, wherein: a first gear assembly (16) is arranged on the backstitch manual wrench assembly (15), a second gear assembly (17) is arranged on the first backstitch crank (22), the first gear assembly (16) and the second gear assembly (17) are mutually meshed, and rotating shafts of the first backstitch connecting rod (14) and the second gear assembly (17) are mutually fixed; the crank mounting seat (12) is respectively connected with the first backstitch connecting rod (14) and the pull rod (7) through the first backstitch transmission crank component (11) and the second backstitch transmission crank component (13).

3. A sewing machine according to claim 2, wherein: the improved seam-cutting machine is characterized in that a second backstitch crank (22-1) is arranged on a rotating shaft of the second gear assembly (17), the second backstitch crank (22-1) is connected with an upper backstitch crank (51) through an upper backstitch connecting rod (50), the upper backstitch crank (51) is arranged on a backstitch shaft (45), a second gear (40) is arranged on the backstitch shaft (45), the second gear (40) is meshed with a first gear (39), the first gear (39) is connected with a connecting rod cam (36) through a rotating shaft, a top block (37) is arranged on the connecting rod cam (36), a universal connecting sleeve (38) is fixed on the top block (37), an upper feeding clutch (33) is fixedly connected with the universal connecting sleeve (38), a lower feeding clutch (32) is arranged on the upper feeding clutch (33) in a matched mode, an upper feeding wheel (31) is arranged on the lower feeding clutch (32), and the lower feeding gear (30) is matched with the upper feeding wheel.

4. A sewing machine according to claim 1, wherein: the needle bar transmission connecting rod assembly (43) is transversely provided with a needle bar seat assembly (42), the needle bar seat assembly (42) is connected with a needle pitch adjusting connecting rod (23) through a needle swinging crank (47), the needle pitch adjusting connecting rod (23) is connected with a first needle pitch adjusting crank (24), the first needle pitch adjusting crank (24) is arranged on a lower feeding shaft (26), and the lower feeding shaft (26) is connected with the needle pitch adjusting swing rod assembly (8) through a second needle pitch adjusting crank (25).

5. A sewing machine according to claim 4, characterized in that: the needle bar seat assembly (42) is connected with an upper feeding shaft (46) through a needle swinging driving connecting rod (48), one end of the upper feeding shaft (46) is provided with an upper second universal connecting rod assembly (35), the second universal connecting rod assembly (35) is provided with an upper feeding one-way bearing driving assembly (34) in a matching mode, and the upper feeding one-way bearing driving assembly (34) is arranged on an upper feeding clutch (33); a needle swinging reversing crank assembly (49) is arranged on the backstitch shaft (45), and the needle swinging reversing crank assembly (49) is matched with the needle swinging driving connecting rod (48).

6. A sewing machine according to claim 1, wherein: the needle pitch adjusting device is characterized in that a needle pitch adjusting crank assembly (21) is arranged at the top end of the needle pitch adjusting pull rod (9), a needle pitch adjusting ball (20) is arranged on the needle pitch adjusting crank assembly (21), and the needle pitch adjusting ball (20) is matched with the needle pitch adjusting cam (19).

7. A sewing machine according to claim 1 or 4, characterized in that: the needle pitch adjusting swing rod assembly (8) comprises a machine pin (8-1), a swinging swing seat (8-2) and a long pin (8-3), wherein the machine pin (8-1) and the long pin (8-3) are respectively positioned on two sides of the swinging swing seat (8-2); a crank long connecting rod (8-4) and a crank short connecting rod (8-8) are arranged on the long pin (8-3), and the crank long connecting rod (8-4) is connected with a second needle pitch adjusting crank (25) and fixed through a second crank short pin (8-6); the needle pitch cam component (10) is arranged on the long pin (8-3) and is positioned between the crank long connecting rod (8-4) and the crank short connecting rod (8-8); the needle pitch adjusting pull rod (9) is fixed on the swing seat (8-2) through a first short crank pin (8-5), a universal shaft (54) is arranged on the needle pitch cam component (10), and a third short crank pin (8-7) is arranged on the short crank connecting rod (8-8).

8. A sewing machine according to claim 7, wherein: a first bearing (58) and a second bearing (59) are respectively arranged at two ends of the one-way bearing driving component (3), a connecting shaft is fixed on the front seam gear (4), the connecting shaft is fixed on a bearing bush (60) in the bearing through a third transmission pin (64), and the bearing bush (60) in the bearing bush is arranged on the one-way bearing driving component (3); the first bearing (58) is provided with a gear shaft connecting block (56), and the gear shaft connecting block (56) is provided with a screw (55).

9. A sewing machine according to claim 8, wherein: the bearing device is characterized in that the middle casing (60) of the bearing is arranged on a driving lever fixing seat (62), the driving lever fixing seat (62) is fixed with the driving lever (2) through a supporting pin (63), and a gear shaft connecting block (56) is fixed with the driving lever (2) through a first driving pin (57) and a second driving pin (61).