Sewing machine driven by synchronous belt

Abstract

The utility model discloses a synchronous belt transmission sewing machine which comprises a sewing machine body, the sewing machine body is provided with a machine base, a sewing machine head and a rotating shuttle assembly, and a front section main shaft, a rear section main shaft, a front section auxiliary shaft and a rear section auxiliary shaft are arranged on the machine base. A lifting driving device is arranged on the machine base and drives the sewing machine head to ascend and descend so as to adjust the height of the sewing machine head. The front-section main shaft and the front-section auxiliary shaft are arranged on the sewing machine head; the rear-section main shaft is in transmission connection with the front-section main shaft through a first synchronous belt transmission device; the rear-section countershaft is in transmission connection with the front-section countershaft through a second synchronous belt transmission device; therefore, compared with a matching mode of protrusions and grooves, transmission matching among the first synchronous wheel, the second synchronous wheel, the first synchronous belt, the linkage synchronous wheel, the second synchronous belt and the sewing machine head has the advantages that sliding is avoided during sewing, the transmission ratio is accurate, the transmission efficiency is high, the sewing needle pitch is uniform, and the sewing quality consistency is good. And the working process of the sewing machine head is more stable.

Description

Technical Field

[0001] The utility model relates to the field of sewing machines, in particular to a sewing machine driven by a synchronous belt. Background Art

[0002] The luggage sewing machine is one of the most commonly used sewing machines in luggage making. It can also be called an industrial flat-bed sewing machine. It can be used to sew fabrics, linings and other details of luggage. It has the characteristics of fast speed, uniform stitching and convenient adjustment of thread tension.

[0003] The prior art discloses a sewing machine with a synchronous belt drive, comprising a main shaft, a machine head, a tooth frame and a driving motor; a sewing mechanism is provided below the machine head, the main shaft is arranged between the machine head and the driving motor, the driving motor drives the main shaft to rotate to drive the sewing mechanism to work, a tooth frame is provided below the machine head, and a gap is provided between the machine head and the tooth frame for placing fabric; the main shaft comprises a front-section main shaft and a rear-section main shaft; the front-section main shaft is connected to the machine head, and the rear-section main shaft is rotatably connected to the driving motor; a first connecting component is provided at the end where the front-section main shaft is connected to the rear-section main shaft, and a second connecting component is provided at the end where the rear-section main shaft is connected to the front-section main shaft. The second connecting assembly can slide against each other in the vertical direction to separate or connect the two connecting assemblies; when the sewing machine is not working, the head moves upward in the vertical direction away from the tooth frame, so that the first connecting assembly and the second connecting assembly are separated from each other; when the sewing machine is to be used, the head moves downward in the vertical direction, so that the first connecting assembly and the second connecting assembly are connected to each other, and the driving motor drives the rear main shaft to rotate, thereby driving the front main shaft to rotate to drive the sewing mechanism to work, thereby sewing the fabric; so that the sewing mechanism under the head can be lifted to a greater height, so that fluffy fabrics or thicker fabrics can be sewn; However, this type of synchronous belt drive sewing machine has the following defects:

[0004] For example, the first connecting component and the second connecting component are two parts of a coupling; one connecting component is provided with a groove, and the other connecting component is provided with a protrusion. When the sewing machine is not in operation, the machine head moves upward in the vertical direction away from the tooth frame, so that the first connecting component and the second connecting component are separated from each other; the mating mode of the protrusion and the groove requires high-precision machining of the connecting mating surfaces of the first connecting component and the second connecting component, otherwise they cannot be used together;

[0005] Secondly, when the machine head and the front main shaft slide against the rear main shaft and the driving motor in the vertical direction, the first connecting assembly and the second connecting assembly can be separated from each other, so that the sewing mechanism under the machine head can be lifted to a greater height. This will result in the protrusion not being able to be fully engaged in the groove during sewing, resulting in the driving force of the driving motor to drive the rear main shaft to rotate not being able to be fully applied to the front main shaft, thereby affecting the operation of the sewing mechanism and reducing the product qualification rate of the sewing machine.

[0006] Therefore, it is necessary to study a new technical solution to solve the above problems. Utility Model Content

[0007] In view of this, the present invention aims to address the deficiencies in the prior art, and its main purpose is to provide a sewing machine with a synchronous belt drive. Through the structural design of the first synchronous belt transmission device and the second synchronous belt transmission device, the transmission cooperation between the first synchronous wheel, the second synchronous wheel, the first synchronous belt, the linkage synchronous wheel, the second synchronous belt and the sewing machine head is compared with the cooperation mode of the protrusion and the groove. During sewing, there is no slippage, an accurate transmission ratio, and high transmission efficiency, which ensures uniform sewing stitch length and good consistency of sewing quality, making the working process of the sewing machine head more stable and the buffering effect softer.

[0008] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0009] A synchronous belt-driven sewing machine comprises a sewing machine body having a machine base, a sewing machine head, and a rotary hook assembly; a lifting drive device is provided on the machine base, and the lifting drive device drives the sewing machine head to rise and fall to adjust the height of the sewing machine head; the sewing machine body is provided with a front section main shaft, a rear section main shaft, a front section secondary shaft, a rear section secondary shaft, and a main shaft drive device that drives the rear section main shaft to rotate; the front section main shaft is drivingly connected to the front section secondary shaft; and the characteristics are:

[0010] The front main shaft and the front secondary shaft are arranged on the sewing machine head; the front end of the rear main shaft is connected to the rear end of the front main shaft through a first synchronous belt transmission device; the front end of the rear secondary shaft is connected to the rear end of the front secondary shaft through a second synchronous belt transmission device;

[0011] The first synchronous belt transmission device and the second synchronous belt transmission device each include a first movable housing, a second movable housing, a first synchronous belt, a linkage synchronous wheel, a second synchronous belt, and a first synchronous wheel provided at the front end of the corresponding rear main shaft and the rear secondary shaft, and a second synchronous wheel provided at the rear end of the corresponding front main shaft and the front secondary shaft; the linkage synchronous wheels are provided with a first linkage wheel and a second linkage wheel, the first synchronous belt is drivingly connected between the first synchronous wheel and the first linkage wheel, the first movable housing is movably sleeved around the first synchronous wheel, the first synchronous belt, and the first linkage wheel; the second synchronous belt is drivingly connected between the second synchronous wheel and the second linkage wheel, the second movable housing is movably sleeved around the second synchronous wheel, the second synchronous belt, and the second linkage wheel;

[0012] When the lifting drive device drives the sewing machine head to rise, the front main shaft and the front auxiliary shaft rise together with the sewing machine head, and the second synchronous wheel pulls the linked synchronous wheel through the second synchronous belt to rotate upward around the first synchronous wheel, so that the second movable shell is arranged at an angle to the first movable shell;

[0013] When the lifting drive device drives the sewing machine head to descend, the front main shaft and the front auxiliary shaft descend together with the sewing machine head, and the linked synchronous wheel rotates downward around the first synchronous wheel, so that the second movable shell is aligned with the first movable shell.

[0014] As a preferred solution, the linked synchronous wheel is also provided with a rotating part, a first synchronous belt tensioning plate, a second synchronous belt tensioning plate, a transmission shaft, a first bearing and a second bearing, and the first linked wheel and the second linked wheel are respectively arranged at the front and rear ends of the rotating part; the rotating part is sleeved on the outside of the transmission shaft; the first bearing and the second bearing are respectively arranged at the front and rear ends of the transmission shaft, the first bearing is transmission-connected to the first synchronous belt tensioning plate, and the second bearing is transmission-connected to the second synchronous belt tensioning plate.

[0015] As a preferred solution, the rear main shaft is connected to the rear secondary shaft through a connecting piece so that the power of the rear main shaft is transmitted to the rear secondary shaft, so that the rear main shaft and the rear secondary shaft respectively drive the synchronous belt transmission device to synchronously drive the sewing machine head up and down.

[0016] As a preferred solution, an upper connecting arm and a lower connecting arm are spaced apart on the machine base; an escape position is formed between the lower end surface of the upper connecting arm and the upper end surface of the lower connecting arm to provide an escape space for the product to be sewn.

[0017] As a preferred solution, the sewing machine head is arranged on the upper connecting arm, and a sewing space is formed between the lower end surface of the sewing machine head and the upper end surface of the rotary shuttle. The lifting drive device drives the sewing machine head to rise and fall to adjust the height of the sewing space.

[0018] As a preferred solution, the upper connecting arm is provided with an upper front connecting arm and an upper front extension shell, and the sewing machine head is provided on the upper front extension shell; the upper connecting arm is provided with a mounting frame and a lower pressure piece; one end of the lower pressure piece is connected to the output end of the lifting drive device, and the other end of the lower pressure piece is connected to the upper front extension shell, and the lifting drive device drives the lower pressure piece to rise and fall to adjust the height of the sewing machine head.

[0019] As a preferred solution, a guide rail is provided on the front side of the mounting frame; and a cross connecting groove is provided on the upper end surface of the upper front extension shell;

[0020] The rear end of the pressing member is connected to the mounting frame through a connecting frame, and a slider for matching with the guide rail is provided on the rear side of the connecting frame. The slider is connected to the guide rail and can slide up and down along the guide rail; a cross connecting portion for connecting with the cross connecting groove is provided on the lower end surface of the connecting frame, and the upper end of the connecting frame is connected to the upper front extension shell, and the cross connecting portion is matched with the cross connecting groove.

[0021] As a preferred solution, a thread take-up assembly is also provided on the side of the sewing machine head, the thread take-up assembly is connected to a needle bar, and a sewing needle adapted to the rotary shuttle is provided at the lower end of the needle bar; the thread take-up assembly includes a head crank installed on one end of the front section main shaft, a needle bar connecting crank provided on the head crank, a thread take-up rod sleeved on the needle bar connecting crank, and a connecting rod connected to the needle bar connecting crank, and the needle bar is rotatably connected to the connecting rod through an iron rod chuck; the head crank is connected to the front end of the front section main shaft.

[0022] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical scheme that it is mainly through the structural design of the first synchronous belt transmission device and the second synchronous belt transmission device that the front end of the rear main shaft is connected to the rear end of the front main shaft through the first synchronous belt transmission device; the front end of the rear secondary shaft is connected to the rear end of the front secondary shaft through the second synchronous belt transmission device; in this way, the processing accuracy requirements of the transmission of the first synchronous belt transmission device and the second synchronous belt transmission device are low; secondly, the transmission cooperation between the first synchronous wheel, the second synchronous wheel, the first synchronous belt, the linkage synchronous wheel, the second synchronous belt and the sewing machine head is compared with the cooperation mode of the protrusion and the groove. During sewing, there is no slippage, an accurate transmission ratio and high transmission efficiency, which ensures uniform sewing stitch length and good consistency of sewing quality, making the working process of the sewing machine head more stable and the buffering effect softer.

[0023] In order to more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a three-dimensional diagram of an embodiment of the present utility model (initial state);

[0025] Figure 2 This is another three-dimensional diagram of an embodiment of the present invention (sewing machine head raised state);

[0026] Figure 3 It is a top view of an embodiment of the present utility model (initial state);

[0027] Figure 4 This is another three-dimensional diagram of an embodiment of the present invention (sewing machine head raised state);

[0028] Figure 5 This is an exploded view of an embodiment of the present utility model;

[0029] Figure 6 This is a schematic diagram of a first partial structure of an embodiment of the present utility model;

[0030] Figure 7 It is a second partial structural diagram of an embodiment of the present utility model.

[0031] Description of the accompanying drawings:

[0032] 10. Machine base

[0033] 20. Lower connecting arm

[0034] 22. Rotary hook assembly 23. Elevating shaft

[0035] 24. Feeding shaft 27. Placement position

[0036] 30. Upper connecting arm 301. Upper front connecting arm

[0037] 302, upper front extension shell 303, cross connection groove

[0038] 31. Front spindle

[0039] 32. Rear main shaft 33. Front secondary shaft

[0040] 34. Rear sub-shaft 35. Sewing machine head

[0041] 351, needle rod 352, head crank

[0042] 353. Thread take-up lever

[0043] 37. Lifting connecting rod assembly

[0044] 361, mounting frame 362, lower pressure piece

[0045] 363. Lifting drive device 364. Guide rail

[0046] 365, connecting frame 366, slider

[0047] 367, cross connection

[0048] 38. Connecting rod 39. First synchronous belt transmission device

[0049] 391, linkage synchronous wheel

[0050] 392, first synchronous wheel 393, second synchronous wheel

[0051] 394, first synchronous belt 395, second synchronous belt

[0052] 3911, first linkage wheel 3912, second linkage wheel

[0053] 3913, first movable shell 3914, second movable shell

[0054] 3915, rotating part 3916, first synchronous belt tensioning plate

[0055] 3917, second synchronous belt tensioning plate 3918, drive shaft

[0056] 371. Presser foot lifting eccentric wheel assembly 372. Presser foot lifting connecting rod

[0057] 373. Presser foot lifting crank 374. Presser foot lifting shaft. DETAILED DESCRIPTION

[0058] Please refer to Figures 1 to 7 As shown, it shows the specific structure of an embodiment of the present utility model.

[0059] In the description of the present invention, it should be noted that directional words, such as the terms "up", "down", "front", "back", "left", "right", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings or during normal wear and use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention.

[0060] A synchronous belt driven sewing machine comprises a sewing machine main body.

[0061] The sewing machine body comprises a base 10, a sewing head 35, and a rotary hook assembly 22; a front main shaft 31, a rear main shaft 32, a front secondary shaft 33, a rear secondary shaft 34, and a main shaft drive device for driving the rear main shaft; the front main shaft 31 is transmission-connected to the front secondary shaft 33; a lifting drive device 363 is provided on the base 10, and the lifting drive device 363 drives the sewing head 35 up and down to adjust the height of the sewing head;

[0062] The front main shaft 31 and the front secondary shaft 33 are arranged on the sewing machine head 35; the front end of the rear main shaft 32 is connected to the rear end of the front main shaft 31 through a first synchronous belt transmission device 39; the front end of the rear secondary shaft 34 is connected to the rear end of the front secondary shaft 33 through a second synchronous belt transmission device;

[0063] The first and second synchronous belt transmission devices each include a first movable housing 3913, a second movable housing 3914, a first synchronous belt 394, a linkage synchronous wheel 391, a second synchronous belt 395, and a first synchronous wheel 392 disposed at the front end of the corresponding rear main shaft 32 and rear secondary shaft 34, and a second synchronous wheel 393 disposed at the rear end of the corresponding front main shaft 31 and front secondary shaft 33.

[0064] The linkage synchronous wheel 391 is provided with a first linkage wheel 3911 and a second linkage wheel 3912. The first synchronous belt 394 is connected between the first synchronous wheel 392 and the first linkage wheel 3911. The first movable shell 3913 is movably mounted on the first synchronous wheel 392, the first synchronous belt 394 and the first linkage wheel 3911.

[0065] The second synchronous belt 395 is connected between the second synchronous wheel 393 and the second linkage wheel 3912. The second movable shell 3914 is movably mounted on the second synchronous wheel 393, the second synchronous belt 395 and the second linkage wheel 3912.

[0066] like Figure 2 The figure shows the sewing machine in the ascending state. When the lifting drive device 363 drives the sewing machine head 35 to ascend, the front main shaft 31 and the front secondary shaft 33 ascend together with the sewing machine head 35. The second synchronous wheel 393 pulls the linked synchronous wheel 391 through the second synchronous belt 395 to rotate upward around the first synchronous wheel 392, so that the second movable shell 3914 is arranged at an angle to the first movable shell 3913.

[0067] like Figure 1 As shown, the default is the initial state. When the lifting drive device 363 drives the sewing machine head 35 to descend, the front main shaft 31 and the front secondary shaft 33 descend together with the sewing machine head 35, and the linked synchronous wheel 39 rotates downward around the first synchronous wheel 392, so that the second movable shell 3914 is aligned with the first movable shell 3913.

[0068] Preferably, the linked synchronous wheel 391 is also provided with a rotating part, a first synchronous belt tensioning plate 3916, a second synchronous belt tensioning plate 3917, a transmission shaft 3918, a first bearing and a second bearing, and the first linked wheel 3911 and the second linked wheel 3912 are respectively arranged at the front and rear ends of the rotating part; the rotating part is sleeved on the outside of the transmission shaft 3918; the first bearing and the second bearing are respectively arranged at the front and rear ends of the transmission shaft, and the first bearing is transmission-connected to the first synchronous belt tensioning plate 3916, and the second bearing is transmission-connected to the second synchronous belt tensioning plate 3917.

[0069] Preferably, the rear main shaft 32 is connected to the rear secondary shaft 34 through a connecting piece, so that the power of the rear main shaft 32 is transmitted to the rear secondary shaft 34, so that the rear main shaft and the rear secondary shaft respectively drive the synchronous belt transmission device to synchronously drive the sewing machine head up and down.

[0070] Preferably, an upper connecting arm 30 and a lower connecting arm 20 are spaced apart on the machine base 10; an escape position is formed between the lower end surface of the upper connecting arm 30 and the upper end surface of the lower connecting arm 20 to provide an escape space for the product to be sewn.

[0071] Preferably, the sewing machine head 35 is arranged on the upper connecting arm 30, and a sewing space is formed between the lower end surface of the sewing machine head 35 and the upper end surface of the rotary hook 22. The lifting drive device 363 drives the sewing machine head 35 to rise and fall to adjust the height of the sewing space. When the inner side of the luggage is sewn, sufficient avoidance space is provided for the luggage to be sewn. Before sewing, the sewing machine head 35 is lifted to a high position by the lifting drive device 363, so that the distance of the placement position 27 is increased, and there is sufficient operating space. At this time, due to the increase in the operating space, the loading operation process is more convenient. After the loading is completed, the lifting drive device 363 drives the sewing machine head 35 to move down to a low position again, so that the sewing machine head 35 is in the normal working position, and the corresponding sewing operation can be carried out. After sewing is completed, the lifting drive device 363 can also be used to drive the sewing machine head 35 to move up to a high position again, thereby improving the convenience of the material removal process.

[0072] Preferably, the upper connecting arm 30 is provided with an upper front connecting arm 301 and an upper front extension shell 302, and the sewing machine head 35 is provided on the upper front extension shell 302; the upper connecting arm 30 is provided with a mounting frame 361 and a lower pressure piece 362; one end of the lower pressure piece 362 is connected to the output end of the lifting drive device 363, and the other end of the lower pressure piece 362 is connected to the upper front extension shell 302, and the lifting drive device 363 drives the lower pressure piece 362 to rise and fall to adjust the height of the sewing machine head 35.

[0073] Preferably, a guide rail 364 is provided on the front side of the mounting frame 361; a cross connecting groove 303 is provided on the upper end surface of the upper front extension shell 302; the rear end of the pressing member 362 is connected to the mounting frame 361 through a connecting frame 365, and a slider 366 for matching with the guide rail 364 is provided on the rear side of the connecting frame 365, and the slider 366 is connected to the guide rail 364 and can slide up and down along the guide rail 364; a cross connecting portion 367 for connecting with the cross connecting groove 303 is provided on the lower end surface of the connecting frame 365, and the upper end of the connecting frame 365 is connected to the upper front extension shell 302, and the cross connecting portion 367 is matched with the cross connecting groove 303. The use of a sliding connection between the slider 366 and the guide rail 364 reduces the number of components required for the overall lifting of the sewing machine head 35, effectively improving its compactness. Furthermore, the transmission gap is small, and the transmission is stable and precise. Furthermore, when the lifting drive 363 controls the upward movement of the sewing machine, the slider 366 can slide upward within the sliding guide groove of the guide rail 364. The vertically arranged sliding guide groove ensures the accuracy of the slider 366's motion trajectory and provides a good guiding effect. When the sewing machine falls back downward, the slider 366 slides back into position within the sliding guide groove, thereby ensuring accurate and reliable transmission and precise transmission position. Furthermore, the design between the cross-connecting groove 303 and the cross-connecting portion 367 enhances the stability of the connection between the connecting frame 365 and the upper front extension shell 302, thereby ensuring the lifting or lowering force exerted by the lifting drive 363 when the sewing machine head 35 is raised or lowered.

[0074] Preferably, a thread take-up assembly is also provided on the side of the sewing machine head 35, and the thread take-up assembly is connected to a needle bar 351, and a sewing needle adapted to the rotary hook 22 is provided at the lower end of the needle bar 351; the thread take-up assembly includes a head crank 352 installed on one end of the front main shaft 31, a needle bar 351 connecting crank provided on the head crank 352, a thread take-up rod 353 sleeved on the needle bar 351 connecting crank, and a connecting rod connected to the needle bar 351 connecting crank, and the needle bar 351 is rotatably connected to the connecting rod through an iron rod clamp; the head crank 352 is connected to the front end of the front main shaft 31.

[0075] The lower connecting arm 20 is further provided with a tooth lifting shaft 23 and a feeding shaft 24, one end of the tooth lifting shaft 23 and the feeding shaft 24 are connected to one end of the rotary hook 22 through a third synchronous belt transmission assembly;

[0076] When the sewing machine is working, the lifting drive device 363 drives the sewing machine head 35 to move toward the shuttle assembly 22, and the following main shaft drive device drives the rear main shaft 32 to rotate, and drives the rear secondary shaft 34 to rotate, so as to drive the corresponding synchronous belt drive device 39 to link the front main shaft 31 and the front secondary shaft 33 to rotate, and then synchronously drive the sewing machine head 35 to work, and the rear main shaft 32 drives the tooth lifting shaft 23 and the feed shaft 24 to rotate respectively through the connecting rod 38, so as to drive the shuttle 22 to rotate.

[0077] The rear end of the front main shaft 31 and one end of the front secondary shaft 33 are both connected to the sewing machine head 35; the rear main shaft 32 is connected to the rear secondary shaft 34, so that the power of the rear main shaft 32 is transmitted to the rear secondary shaft 34, so that the rear main shaft 32 and the rear secondary shaft 34 respectively drive the sewing machine head 35 up and down synchronously under the transmission of the synchronous belt transmission device 39.

[0078] The rear section main shaft 32 is connected to the tooth lifting shaft 23 and the feed shaft 24 respectively through the connecting rod 38; the main shaft driving device serves as the main power source for the sewing machine, and is fixedly installed on the body of the sewing machine. The output shaft of the main shaft driving device is connected to the rear section main shaft 32. When the main shaft driving device is working, it drives the rear section main shaft 32 to rotate around the axis of the rear section main shaft 32; wherein, the rear section main shaft 32 can be directly connected to the output device of the main shaft driving device; or, it can also be connected to the output shaft of the drive motor through a clutch or a gear set, so as to facilitate the main shaft to obtain a suitable speed or torque.

[0079] The front section countershaft 33 and the rear section countershaft 34 are arranged parallel to the front section main shaft 31 and the rear section main shaft 32; the other end of the rear section countershaft 34 is connected to the tooth lifting shaft 23 through a swing link 38; one end of the rear section countershaft 34 is connected to one end of the front section countershaft 33 through a countershaft synchronous belt linkage assembly; the other end of the front section countershaft 33 is connected to the other side of the sewing machine head 35;

[0080] The sewing machine head 35 is also provided with a thread take-up assembly, which is connected to a needle bar 351, and a sewing needle adapted to the rotary hook 22 is provided at the lower end of the needle bar 351; the thread take-up assembly includes a head crank 352 installed on one end of the front main shaft 31, a needle bar 351 connecting crank provided on the head crank 352, a thread take-up rod 353 sleeved on the needle bar 351 connecting crank, and a connecting rod connected to the needle bar 351 connecting crank, and the needle bar 351 is rotatably connected to the connecting rod through an iron rod clamp; the head crank 352 is connected to the front end of the front main shaft 31.

[0081] The sewing machine head 35 is also provided with a front crank of the feed shaft 24, a feed mechanism crank and a needle bar 351 frame for installing the needle bar 351. One end of the front crank of the feed shaft 24 is connected to the other end of the front section auxiliary shaft 33, and the other end of the front crank of the feed shaft 24 is movably connected to one end of the feed mechanism crank, and the other end of the feed mechanism crank is connected to the needle bar 351 frame.

[0082] Preferably, the lifting connecting rod assembly 37 includes a presser foot lifting eccentric wheel group 371, a presser foot lifting connecting rod 372, a presser foot lifting crank 373 and a presser foot lifting shaft 374; the lifting connecting rod 38 assembly 37 is used to convert the rotational motion of the front section main shaft 31 and the rear section main shaft 32 into the reciprocating swinging motion of the presser foot lifting shaft 374.

[0083] The presser foot lifting eccentric wheel group 371 is sleeved on the front main shaft and is configured to swing when the rear main shaft 32 rotates. One end of the presser foot lifting connecting rod 372 is connected to the presser foot lifting eccentric wheel group 371, and the other end of the presser foot lifting connecting rod 372 is fixedly connected to one end of the presser foot lifting crank 373. One end of the presser foot lifting shaft 374 is movably connected to the other end of the presser foot lifting crank 373, and the other end of the presser foot lifting shaft 374 is connected to a presser foot interaction component for converting the reciprocating swing of the presser foot lifting shaft 374 into an up and down reciprocating motion of the presser foot. When the main shaft rotates, the presser foot lifting eccentric wheel group 371 swings. When the main shaft rotates, the eccentric wheel of the presser foot lifting eccentric wheel group 371 rotates eccentrically around the axis of the main shaft, thereby driving the crank to swing.

[0084] The presser foot interaction assembly includes a first oscillating presser foot connecting rod 38, a second oscillating presser foot connecting rod 38, a crank of the presser foot connecting rod 38, and an oscillating presser foot rod; one end of the first oscillating presser foot connecting rod 38 is connected to the presser foot lifting shaft 374, the other end of the first oscillating presser foot connecting rod 38 is hinged to the second oscillating presser foot connecting rod 38, the other end of the second oscillating presser foot connecting rod 38 is hinged to the crank of the presser foot connecting rod 38, the crank of the presser foot connecting rod 38 is hinged to the oscillating presser foot rod, and the presser foot is connected to the oscillating presser foot rod. The transmission of the second oscillating presser foot connecting rod 38 and the crank of the presser foot connecting rod 38 is converted into the up and down movement of the oscillating presser foot rod. The presser foot of the sewing machine is connected to the oscillating presser foot rod, so that the presser foot also moves up and down with the oscillating presser foot rod, realizing sewing work.

[0085] The design focus of the present utility model is that, mainly through the structural design of the first synchronous belt transmission device and the second synchronous belt transmission device, the front end of the rear main shaft is connected to the rear end of the front main shaft through the first synchronous belt transmission device; the front end of the rear secondary shaft is connected to the rear end of the front secondary shaft through the second synchronous belt transmission device; in this way, the processing accuracy requirements of the transmission of the first synchronous belt transmission device and the second synchronous belt transmission device are low; secondly, the transmission cooperation between the first synchronous wheel, the second synchronous wheel, the first synchronous belt, the linkage synchronous wheel, the second synchronous belt and the sewing machine head is compared with the cooperation mode of the protrusion and the groove. During sewing, there is no slippage, an accurate transmission ratio and high transmission efficiency, which ensures uniform sewing stitch length and good consistency of sewing quality, making the working process of the sewing machine head more stable and the buffering effect softer.

[0086] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A synchronous belt-driven sewing machine, comprising a sewing machine body having a machine base, a sewing machine head, and a rotary hook assembly; a lifting drive device provided on the machine base, the lifting drive device driving the sewing machine head to move up and down to adjust the height of the sewing machine head; a front main shaft, a rear main shaft, a front countershaft, a rear countershaft, and a main shaft drive device driving the rear main shaft; the front main shaft being drivingly connected to the front countershaft; and characterized in that: The front main shaft and the front secondary shaft are arranged on the sewing machine head; the front end of the rear main shaft is connected to the rear end of the front main shaft through a first synchronous belt transmission device; the front end of the rear secondary shaft is connected to the rear end of the front secondary shaft through a second synchronous belt transmission device; The first synchronous belt transmission device and the second synchronous belt transmission device each include a first movable housing, a second movable housing, a first synchronous belt, a linkage synchronous wheel, a second synchronous belt, and a first synchronous wheel provided at the front end of the corresponding rear main shaft and the rear secondary shaft, and a second synchronous wheel provided at the rear end of the corresponding front main shaft and the front secondary shaft; the linkage synchronous wheels are provided with a first linkage wheel and a second linkage wheel, the first synchronous belt is drivingly connected between the first synchronous wheel and the first linkage wheel, the first movable housing is movably sleeved around the first synchronous wheel, the first synchronous belt, and the first linkage wheel; the second synchronous belt is drivingly connected between the second synchronous wheel and the second linkage wheel, the second movable housing is movably sleeved around the second synchronous wheel, the second synchronous belt, and the second linkage wheel; When the lifting drive device drives the sewing machine head to rise, the front main shaft and the front auxiliary shaft rise together with the sewing machine head, and the second synchronous wheel pulls the linked synchronous wheel through the second synchronous belt to rotate upward around the first synchronous wheel, so that the second movable shell is arranged at an angle to the first movable shell; When the lifting drive device drives the sewing machine head to descend, the front main shaft and the front auxiliary shaft descend together with the sewing machine head, and the linked synchronous wheel rotates downward around the first synchronous wheel, so that the second movable shell is aligned with the first movable shell.

2. The synchronous belt driven sewing machine according to claim 1, characterized in that: The linked synchronous wheel is also provided with a rotating part, a first synchronous belt tensioning plate, a second synchronous belt tensioning plate, a transmission shaft, a first bearing and a second bearing. The first linked wheel and the second linked wheel are respectively arranged at the front and rear ends of the rotating part; the rotating part is sleeved on the outside of the transmission shaft; the first bearing and the second bearing are respectively arranged at the front and rear ends of the transmission shaft, the first bearing is transmission-connected to the first synchronous belt tensioning plate, and the second bearing is transmission-connected to the second synchronous belt tensioning plate.

3. The synchronous belt driven sewing machine according to claim 1, characterized in that: The rear main shaft is connected to the rear secondary shaft through a connecting piece, so that the power of the rear main shaft is transmitted to the rear secondary shaft, so that the rear main shaft and the rear secondary shaft respectively drive the synchronous belt transmission device to synchronously drive the sewing machine head up and down.

4. The synchronous belt driven sewing machine according to claim 1, characterized in that: An upper connecting arm and a lower connecting arm are spaced apart on the machine base; a relief position is formed between the lower end surface of the upper connecting arm and the upper end surface of the lower connecting arm to provide relief space for products to be sewn.

5. The synchronous belt driven sewing machine according to claim 4, characterized in that: The sewing machine head is arranged on the upper connecting arm, and a sewing space is formed between the lower end surface of the sewing machine head and the upper end surface of the rotary shuttle. The lifting drive device drives the sewing machine head to rise and fall to adjust the height of the sewing space.

6. The synchronous belt driven sewing machine according to claim 4, characterized in that: The upper connecting arm is provided with an upper front connecting arm and an upper front extension shell, and the sewing machine head is provided on the upper front extension shell; the upper connecting arm is provided with a mounting frame and a lower pressing piece; one end of the lower pressing piece is connected to the output end of the lifting drive device, and the other end of the lower pressing piece is connected to the upper front extension shell, and the lifting drive device drives the lower pressing piece to rise and fall to adjust the height of the sewing machine head.

7. The synchronous belt driven sewing machine according to claim 6, characterized in that: A guide rail is provided on the front side of the mounting frame; a cross connecting groove is provided on the upper end surface of the upper front extension shell; The rear end of the pressing member is connected to the mounting frame through a connecting frame, and a slider for matching with the guide rail is provided on the rear side of the connecting frame. The slider is connected to the guide rail and can slide up and down along the guide rail; a cross connecting portion for connecting with the cross connecting groove is provided on the lower end surface of the connecting frame, and the upper end of the connecting frame is connected to the upper front extension shell, and the cross connecting portion is matched with the cross connecting groove.

8. The synchronous belt driven sewing machine according to claim 2, characterized in that: A thread take-up assembly is also provided on the side of the sewing machine head, and the thread take-up assembly is connected to a needle bar, and a sewing needle adapted to the rotary shuttle is provided at the lower end of the needle bar; the thread take-up assembly includes a head crank installed at one end of the front section main shaft, a needle bar connecting crank provided on the head crank, a thread take-up rod sleeved on the needle bar connecting crank, and a connecting rod connected to the needle bar connecting crank, and the needle bar is rotatably connected to the connecting rod through an iron rod chuck; the head crank is connected to the front end of the front section main shaft.

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