Fabric seam-crossing sensing and sewing device and method

Abstract

The present invention provides a fabric seam-crossing sensing and sewing device and method. The fabric seam-crossing sensing and sewing device comprises a first presser foot bar provided with an outer presser foot, a second presser foot bar provided with an inner presser foot, a presser foot transmission mechanism, a control module, a fabric thickness measurement sensor, an alternating lift amount adjustment mechanism, an alternating lift amount measurement sensor, and an alternating lift amount adjustment drive source; the fabric thickness measurement sensor is obliquely mounted at the bottom of a housing of a sewing machine; in the direction of forward feeding during forward sewing of the sewing machine, measurement points of the fabric thickness measurement sensor falling on the fabric are distributed on the rear sides of the outer presser foot and the inner presser foot; the presser foot transmission mechanism comprises a transmission oscillating seat that determines a presser foot alternating lift amount, and the alternating lift amount adjustment drive source is connected to the transmission oscillating seat by means of the alternating lift amount adjustment mechanism. The present application effectively realizes advance measurement of fabric thickness, thereby adjusting a presser foot alternating lift amount in a timely manner, enabling the presser foot alternating lift amount of the sewing machine to adapt to changes in the fabric thickness, thus improving efficiency, enhancing seam-crossing stitch aesthetics, and ensuring sewing quality.

Description

Cloth overlock detection sewing device and method TECHNICAL FIELD

[0001] The present application relates to the technical field of sewing machines, in particular to a cloth overlock detection sewing device and a cloth overlock detection sewing method using the same. BACKGROUND

[0002] A sewing machine is a machine that uses one or more threads to form one or more stitches on a piece of fabric. On the market, there are flat sewing machine types, comprehensive feeding machine types, etc.; among them, the feeding of the flat sewing machine type is only completed by its feeding teeth; the feeding of the comprehensive feeding machine type is completed by its needle, inner presser foot, outer presser foot and feeding teeth, such as the comprehensive feeding sewing machine disclosed in the Chinese Utility Model Patent with the publication number CN216864499U.

[0003] In a comprehensive feeding sewing machine, the size of the presser foot alternating amount has an important influence on the performance of the comprehensive feeding sewing machine in processing different thicknesses and different types of fabric, especially in the overlock (crossing the edge of thick material) and over-thickness (processing thick material layering) performance. The presser foot alternating amount of the comprehensive feeding sewing machine refers to the amplitude and frequency of the up-and-down alternating motion of the inner presser foot and the outer presser foot of the comprehensive feeding sewing machine during the sewing process.

[0004] Generally, a reasonable presser foot alternating amount of the comprehensive feeding sewing machine can ensure smooth operation of the sewing machine when overlocking and over-thickness. When the comprehensive feeding sewing machine sews thicker fabric or crosses the edge of thick material, the presser foot (i.e. the inner presser foot and the outer presser foot) needs enough up-and-down motion space to adapt to the thickness change of the fabric. If the presser foot alternating amount is too small, the presser foot cannot provide enough lifting height when overlocking, resulting in fabric jamming, uneven stitches or even needle breakage. For example: in the view shown in FIG. 1, A1 and A2 are the pinching of the needle caused by the small presser foot alternating amount, which is a bad stitch, ultimately resulting in uneven stitches. For another example: in the view shown in FIG. 2, when the comprehensive feeding sewing machine overlocks uphill (i.e. overlocks uphill), the inner presser foot 20 cannot go uphill due to the small presser foot alternating amount, and the inner presser foot 20 cannot go up at the overlocking or thick material edge due to the large height difference of the fabric, causing the comprehensive feeding sewing machine to be stuck at this point and unable to continue smooth sewing, which can seriously affect production efficiency and sewing quality, increasing the scrap rate. For another example: in the view shown in FIG. 3, when the comprehensive feeding sewing machine overlocks downhill, the outer presser foot 10 cannot go downhill due to the small presser foot alternating amount, and the outer presser foot 10 cannot effectively descend at the overlocking or thick material edge due to the large height difference of the fabric, causing the comprehensive feeding sewing machine to be stuck at this point and unable to continue smooth sewing, which can seriously affect production efficiency and sewing quality, increasing the scrap rate. In addition, when processing thick material layering, the presser foot also needs enough pressure to ensure the close combination between the fabric layers, preventing the thread from loosening or skipping.

[0005] To solve the above problems, in the actual sewing process, the operator manually adjusts the presser foot alternation amount of the comprehensive feeding sewing machine when the comprehensive feeding sewing machine is climbing or descending the ridge. However, frequent manual adjustment of the presser foot alternation amount is time-consuming and laborious, affects the sewing efficiency, and long-term manual adjustment increases the fatigue of the operator, further affecting the accuracy and efficiency of the adjustment.

[0006] Based on the problem of manually adjusting the presser foot alternation amount of the comprehensive feeding sewing machine, some sewing machine manufacturers have developed comprehensive feeding sewing machines that can automatically adjust the presser foot alternation amount. However, the primary purpose of achieving automatic adjustment of the presser foot alternation amount of the comprehensive feeding sewing machine is to be able to detect the thickness change of the sewing material. In existing sewing machines, detecting the thickness change of the fabric is crucial to achieving high-quality sewing.

[0007] For example: the sewing machine with a presser foot pressure adjusting function disclosed in the Chinese invention patent with the authorization announcement number CN109825965B has a sensor at the connection between the upper shaft of the presser foot and the lower shaft of the presser foot. The sensor can be a Hall element, a displacement sensor, or a pair of infrared sensors. The sensor senses the position change of the upper shaft of the presser foot and the lower shaft of the presser foot to detect the thickness of the fabric. However, in this sewing machine, the installation position of the sensor is distributed at the presser foot along the feeding direction of the sewing machine. When the sensor detects the thickness change of the sewing material, the sewing material has already been moved to the presser foot, resulting in insufficient real-time response during the sewing process and affecting the sewing quality.

[0008] For example: the front guide type sewing material thickness detection mechanism and sewing machine disclosed in the Chinese utility model patent with the authorization announcement number CN212963181U uses a front roller assembly to achieve a pilot effect. The roller assembly is pressed on the sewing material and located in front of the presser foot. The sewing material thickness sensor senses the thickness change of the sewing material in advance to provide more timely adjustment. Although it can solve the problem of detection lag, it brings new problems: 1. The front roller assembly affects the operator's line of sight and operating space, increasing the difficulty of operation; 2. The structure design is complex, increasing the manufacturing cost and maintenance cost of the sewing machine; 3. The installation and calibration of the front roller assembly also require more time and experience, which will reduce production efficiency. SUMMARY

[0009] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a fabric ridge detection sewing device that can detect the thickness of the sewing material in advance and avoid affecting the operator's line of sight and operating space, as well as simplifying the structure.

[0010] In order to achieve the above object, the present application provides a cloth overlock detection sewing device, which comprises a main shaft rotatably supported in a sewing machine housing, a first presser bar and a second presser bar movably assembled in the sewing machine housing, an outer presser foot installed at the lower end of the first presser bar, an inner presser foot installed at the lower end of the second presser bar, and a presser foot transmission mechanism, wherein the main shaft is connected with the first presser bar and the second presser bar through the presser foot transmission mechanism; the cloth overlock detection sewing device further comprises a control module, a sewing material thickness detection sensor, an alternating amount adjusting mechanism, an alternating amount detection sensor, and an alternating amount adjusting driving source installed on the sewing machine housing.

[0011] The sewing material thickness detection sensor is obliquely installed at the bottom of the sewing machine housing; along the feeding direction of the forward feeding during the forward sewing of the sewing machine, the detection points of the sewing material thickness detection sensor falling on the sewing material are distributed at the rear side of the outer presser foot and the inner presser foot.

[0012] The presser foot transmission mechanism comprises a transmission swing seat rotatably supported in the sewing machine housing, wherein the angle of the transmission swing seat determines the alternating amount of the presser foot, the alternating amount adjusting driving source is connected with the transmission swing seat through the alternating amount adjusting mechanism, and the alternating amount detection sensor is used for detecting the angle of the transmission swing seat.

[0013] The sewing material thickness detection sensor, the alternating amount adjusting driving source and the alternating amount detection sensor are all communicatively connected with the control module.

[0014] Further, the sewing material thickness detection sensor is a laser displacement sensor.

[0015] Further, the outer presser foot and the inner presser foot are both provided with needle holes allowing the needle in the sewing machine to pierce;

[0016] Along the feeding direction of the forward feeding during the forward sewing of the sewing machine, the detection points of the sewing material thickness detection sensor falling on the sewing material are aligned with the needle holes.

[0017] Further, the alternating amount adjusting mechanism comprises an alternating amount adjusting shaft rotatably supported in the sewing machine housing and an alternating amount adjusting crank fixed on the alternating amount adjusting shaft, the alternating amount adjusting driving source is connected with the alternating amount adjusting crank and is used for driving the alternating amount adjusting crank to rotate, one end of the alternating amount adjusting shaft is fixed to the transmission swing seat, and the rotating axis of the alternating amount adjusting shaft is collinear with the rotating axis of the transmission swing seat.

[0018] Further, the alternating amount detection sensor is a potentiometer, and the potentiometer is connected with the other end of the alternating amount adjusting shaft.

[0019] Further, the presser foot driving mechanism comprises an alternate amount feeding eccentric wheel fixed on the main shaft, an alternate amount feeding connecting rod, a first feeding connecting rod, a second feeding connecting rod, an upper crank shaft rotatably supported in the sewing machine housing, an alternate amount lifting crank and an upper feeding crank both fixed on the upper crank shaft, a presser foot feeding connecting rod, and a presser foot feeding connecting crank, one end of the alternate amount feeding connecting rod is rotatably sleeved on the outer periphery of the alternate amount feeding eccentric wheel, the other end of the alternate amount feeding connecting rod, one end of the first feeding connecting rod, and one end of the second feeding connecting rod are coaxially hinged, the other end of the first feeding connecting rod is hinged with the driving swing seat, the other end of the second feeding connecting rod is hinged with the alternate amount lifting crank, the two ends of the presser foot feeding connecting rod are respectively hinged with the upper feeding crank and the presser foot feeding connecting crank, the first presser foot rod and the second presser foot rod are both hinged with the presser foot feeding connecting crank, the hinged points of the presser foot feeding connecting crank with the presser foot feeding connecting rod, the first presser foot rod, and the second presser foot rod are in a triangular distribution.

[0020] Further, the present application also provides a fabric overlock detection sewing method, which uses the fabric overlock detection sewing device as described above, and comprises the following steps:

[0021] S1, the sewing machine starts sewing;

[0022] S2, the fabric thickness detection sensor detects the first real-time thickness of the fabric located at the rear side of the outer presser foot and the inner presser foot, and feeds the first real-time thickness to the control module, and the control module obtains the height difference △H of the fabric to be sewn according to the first real-time thickness of the fabric;

[0023] S3, the alternate amount detection sensor detects the current angle of the driving swing seat, and feeds the current angle to the control module, and the control module obtains the current presser foot alternate amount of the sewing machine according to the current angle of the driving swing seat, the current presser foot alternate amount has an alternate amount height value h, and the control module sets the current presser foot alternate amount as the initial presser foot alternate amount;

[0024] S4, the control module judges whether the absolute value of the height difference △H of the fabric to be sewn is greater than or equal to the alternate amount height value h of the current presser foot alternate amount: if not, step S5 is executed; if yes, step S6 is executed;

[0025] S5, return to step S2 described above;

[0026] S6, the control module judges whether the fabric is to be sewn uphill or downhill according to the real-time thickness of the fabric;

[0027] S7, the control module judges that the fabric is to be sewn uphill, and sequentially executes steps S71 to S74:

[0028] S71、the control module drives the alternate amount adjusting driving source to act, the alternate amount adjusting driving source drives the transmission swing seat to rotate through the alternate amount adjusting mechanism, and the presser foot of the sewing machine alternately increases the amount;

[0029] S72、the control module controls the sewing machine to run and set the number of stitches;

[0030] S73、the control module reads the sewing material thickness detection sensor, and obtains the second real-time thickness of the sewing material located at the rear side of the outer presser foot and the inner presser foot;

[0031] S74、the control module judges whether to descend according to the second real-time thickness of the sewing material, the first real-time thickness, and the alternate amount height value h corresponding to the initial presser foot alternate amount, if not, returns to the above step S73, and if yes, executes the following step S82;

[0032] S8、the control module judges to sew down, and sequentially executes the following steps S81 to S84:

[0033] S81、the control module drives the alternate amount adjusting driving source to act, the alternate amount adjusting driving source drives the transmission swing seat to rotate through the alternate amount adjusting mechanism, and the presser foot of the sewing machine alternately increases the amount;

[0034] S82、the control module controls the sewing machine to run and set the number of stitches;

[0035] S83、the control module drives the alternate amount adjusting driving source to reset, and the sewing machine restores the current presser foot alternate amount in the above step S3;

[0036] S84、returns to the above step S2.

[0037] Further, the alternate amount adjusting driving source is a cylinder or an electromagnet, and the presser foot alternate amount of the sewing machine has two gears.

[0038] Further, the alternate amount adjusting driving source is a motor, and the presser foot alternate amount of the sewing machine has at least two gears.

[0039] Further, the fabric overfeed detection sewing device further comprises a tooth frame, a feeding tooth fixed on the tooth frame, a tooth lifting feeding mechanism connected with the tooth frame, a needle bar movably assembled in the sewing machine housing, a needle installed at the lower end of the needle bar, a fabric piercing driving mechanism, a needle spacing adjusting driving source, and a needle spacing adjusting mechanism, the main shaft is connected with the needle bar through the fabric piercing driving mechanism, the needle spacing adjusting driving source is connected with the tooth lifting feeding mechanism and the fabric piercing driving mechanism through the needle spacing adjusting mechanism, and the needle spacing adjusting driving source is in communication connection with the control module;

[0040] The step S72 in the cloth overfeed detection sewing method is executed in the following steps:

[0041] S721, the control module acquires a target stitch length according to the installation data of the cloth thickness detection sensor and the detection data of the cloth thickness detection sensor;

[0042] S722, the control module drives the stitch length adjustment driving source to act on the feed dog mechanism and the presser foot driving mechanism through the stitch length adjustment mechanism, and adjusts the stitch length of the sewing machine from the current stitch length to the target stitch length;

[0043] S723, the control module controls the sewing machine to run for a set number of stitches at the target stitch length;

[0044] S724, the control module drives the stitch length adjustment driving source to reset, and restores the stitch length of the sewing machine from the target stitch length to the current stitch length before the stitch length adjustment;

[0045] S725, the control module controls the sewing machine to run for a set number of stitches at the current stitch length.

[0046] Further, the feed dog mechanism has a feed dog shaft and a feed dog shaft, which are rotatably supported in the sewing machine base plate;

[0047] The stitch length adjustment driving source is a motor; the stitch length adjustment mechanism includes a stitch length adjustment frame driven to rotate by the stitch length adjustment driving source, a stitch length adjustment pin fixed to the stitch length adjustment frame, a stitch length adjustment seat rotatably supported in the sewing machine housing, a first stitch length adjustment connecting rod, a stitch length adjustment shaft rotatably supported in the sewing machine base plate, a stitch length adjustment crank and a stitch length adjustment swing seat both fixed to the stitch length adjustment shaft, a first feed dog crank connecting rod, a second feed dog crank connecting rod, a lower feed dog connecting rod, a first lower feed dog crank and a second lower feed dog crank both fixed to the feed dog shaft, a second stitch length adjustment connecting rod, a stitch length adjustment swing shaft rotatably supported in the sewing machine housing, and a stitch length adjustment swing crank and a stitch length adjustment swing frame both fixed to the stitch length adjustment swing shaft, the stitch length adjustment seat has an adjustment groove, the stitch length adjustment pin is located in the adjustment groove and in contact with the groove wall of the adjustment groove, the two ends of the first stitch length adjustment connecting rod are hinged to the stitch length adjustment frame and the stitch length adjustment crank respectively, one end of the first feed dog crank connecting rod, one end of the second feed dog crank connecting rod, and one end of the lower feed dog connecting rod are coaxially hinged, the other end of the lower feed dog connecting rod is in transmission connection with the feed dog shaft, the other end of the first feed dog crank connecting rod is hinged to the stitch length adjustment swing seat, one end of the second feed dog crank connecting rod is hinged to the first lower feed dog crank, the two ends of the second stitch length adjustment connecting rod are hinged to the second lower feed dog crank and the stitch length adjustment swing crank respectively, and the second presser foot rod and the needle rod are both movably arranged in the stitch length adjustment swing frame.

[0048] As described above, the fabric overlock detection sewing device and method of the present application have the following beneficial effects:

[0049] The present application can adjust the angle of the transmission swing seat by controlling the action of the alternate amount adjusting driving source, and realize automatic adjustment of the presser foot alternate amount. In particular, the present application realizes early detection of the fabric thickness by tilting the installation of the fabric thickness detection sensor to make the detection points distributed on the rear side of the outer presser foot and the inner presser foot, and can detect and identify the height difference of the fabric to be sewn in advance, so as to timely adjust the presser foot alternate amount, so that the presser foot alternate amount of the sewing machine is self-adaptive to the change of the fabric thickness, which not only improves the efficiency, but also beautifies the overlock stitch and ensures the sewing quality. Moreover, the early detection of the sewing thickness of the present application is realized by tilting the installation of the fabric thickness detection sensor on the bottom of the sewing machine shell, which does not affect the operator's vision and operation space, and can simplify the structure, reduce the cost, and facilitate the installation and calibration. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figs. 1 to 3 are adverse phenomena caused by too small presser foot alternate amount of the existing comprehensive feeding sewing machine.

[0051] Fig. 4 is a structural schematic diagram of a comprehensive feeding sewing machine equipped with the fabric overlock detection sewing device of the present application.

[0052] Fig. 5 is an exploded view of Fig. 4.

[0053] Figs. 6 and 7 are structural schematic diagrams of Fig. 4 in other viewing angles after omitting the sewing machine shell and the sewing machine bottom plate.

[0054] Fig. 8 is a structural schematic diagram of the alternate amount adjusting mechanism and the fabric piercing transmission mechanism in Fig. 4.

[0055] Figs. 9 and 10 are detection principle diagrams of the laser displacement sensor in the present application.

[0056] Figs. 11a to 11c are overlock judgment process schematic diagrams in the present application.

[0057] Fig. 12 is a control principle block diagram of the fabric overlock detection sewing device of the present application.

[0058] Fig. 13 is a flowchart of the first embodiment of the fabric overlock detection sewing method of the present application.

[0059] Fig. 14 is a flowchart of the second embodiment of the fabric overlock detection sewing method of the present application.

[0060] Fig. 15 is a flowchart of the third embodiment of the fabric overlock detection sewing method of the present application.

[0061] Fig. 16 is a flowchart of the fourth embodiment of the fabric overlock detection sewing method of the present application.

[0062] Figure 17 is a schematic view of a needle of a sewing machine just before the needle pierces the stem portion.

[0063] Figure 18 is a stitch formed by the sewing machine of Figure 17.

[0064] Figure 19 is a schematic view of the adjustment of the stitch length in the third and fourth embodiments of the method of the present application.

[0065] Figure 20 is a schematic view of a needle of a sewing machine just before the needle pierces the stem portion in the third and fourth embodiments of the method of the present application.

[0066] Element No. 10 outer presser foot 20 inner presser foot 31 sewing machine housing 32 main shaft 33 first presser bar 34 second presser bar 35 tooth rack 36 feeding tooth 37 needle bar 38 needle 39 sewing machine base plate 41 control module 42 sewing material thickness detection sensor 421 laser emitter 422 light path structure sensor 43 alternating amount detection sensor 51 alternating amount adjustment driving source 52 alternating amount adjustment shaft 53 alternating amount adjustment crank 61 transmission swing seat 62 alternating amount feeding eccentric wheel 63 alternating amount feeding connecting rod 64 first feeding connecting rod 65 second feeding connecting rod 66 upper crank shaft 67 alternating amount lifting crank 68 upper feeding crank 69 presser foot feeding connecting rod 610 presser foot feeding connecting crank 71 needle pitch adjustment driving source 72 needle pitch adjustment rack 73 needle pitch adjustment pin 74Needle spacing adjusting seat 75 First needle spacing adjusting link 76 Needle spacing adjusting shaft 77 Needle spacing adjusting crank 78 Needle spacing adjusting swing seat 79 First feeding crank link 710 Second feeding crank link 711 Lower feeding link 712 First lower feeding crank 713 Second lower feeding crank 714 Second needle spacing adjusting link 715 Needle spacing adjusting swing shaft 716 Needle spacing adjusting swing crank 717 Needle spacing adjusting swing frame 81 Lifting tooth shaft 82 Feeding shaft 83 Lifting tooth crank 84 Lifting tooth link 85 Feeding crank seat 86 Tooth frame pin 91 Needle bar crank 92 Needle bar link 93 Slide guide 94 Needle bar joint DETAILED DESCRIPTION

[0067] The present application is explained by the following specific embodiments, and other advantages and effects of the present application can be easily understood by those skilled in the art from the contents disclosed in the specification.

[0068] It is to be understood that the structures, proportions, sizes, etc. shown in the drawings of the present disclosure are merely used to cooperate with the content disclosed in the present disclosure, to be understood and read by those skilled in the art, and are not used to limit the conditions for implementing the present disclosure, and therefore do not have substantial technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects and purposes that can be achieved by the present disclosure, should still fall within the scope of the technology disclosed by the present disclosure. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present disclosure are only for the convenience of clear description, and are not used to limit the scope of the present disclosure. The change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present disclosure.

[0069] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or indirectly connected to the other element through a middle element.

[0070] In addition, the descriptions involving "first", "second", etc. in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection claimed by the present application.

[0071] As shown in FIGS. 4 and 5, the present application relates to a comprehensive feeding sewing machine, in particular to a cloth overlock detection sewing device assembled in the comprehensive feeding sewing machine, and a cloth overlock detection sewing method using the cloth overlock detection sewing device. Hereinafter, the comprehensive feeding sewing machine is referred to as a sewing machine, and the axial direction of the main shaft 32 in the sewing machine is defined as the left-right direction, and the feeding direction of the sewing machine during sewing is defined as the front direction. Based on this, in the view shown in FIG. 4, the left side of the paper is the left direction, the right side of the paper is the right direction, the front of the paper is the rear direction, the back of the paper is the front direction, the upper side of the paper is the upper direction, and the lower side of the paper is the lower direction.

[0072] As shown in Fig. 4 and Fig. 5, the comprehensive feeding sewing machine comprises a sewing machine housing 31 and a sewing machine base plate 39 which are fixedly arranged, a main shaft 32 which is rotatably supported in the sewing machine housing 31 through a shaft sleeve, a control module 41 and a main motor which are fixedly arranged at the right end side of the sewing machine housing 31, a first presser foot rod 33 which is installed with the outer presser foot 10 at the lower end, a second presser foot rod 34 which is installed with the inner presser foot 20 at the lower end, a presser foot transmission mechanism, a needle rod 37 which is installed with the machine needle 38 at the lower end, a fabric penetrating transmission mechanism, a tooth rack 35 which is fixedly arranged with the feeding tooth 36 at the upper end, and a tooth lifting feeding mechanism.

[0073] The main motor is connected with the right end of the main shaft 32 to drive the main shaft 32 to rotate, and the main motor is in communication connection with the control module 41; the first presser foot rod 33 and the second presser foot rod 34 are movably assembled in the sewing machine housing 31, the main shaft 32 is connected with the first presser foot rod 33 and the second presser foot rod 34 through the presser foot transmission mechanism, and then the feeding power of the outer presser foot 10 and the inner presser foot 20 is derived from the main shaft 32, i.e. from the main motor; the needle rod 37 is movably assembled in the sewing machine housing 31, the main shaft 32 is connected with the needle rod 37 through the fabric penetrating transmission mechanism, and then the fabric penetrating and feeding power of the machine needle 38 is derived from the main shaft 32, i.e. from the main motor; the tooth lifting feeding mechanism is connected with the tooth rack 35, and the tooth lifting feeding mechanism can be connected with the main shaft 32 and driven by the main motor, or an independent motor can be connected with the tooth lifting feeding mechanism.

[0074] As shown in FIG. 4 to FIG. 7, the fabric overlock detection sewing device involved in the present application comprises a main shaft 32, a first presser bar 33, a second presser bar 34, an outer presser foot 10, an inner presser foot 20, a presser foot transmission mechanism and a control module 41, and further comprises a seam thickness detection sensor 42, an alternating amount adjusting mechanism, an alternating amount detection sensor 43 and an alternating amount adjusting drive source 51. The seam thickness detection sensor 42 is obliquely installed at the bottom of the sewing machine housing 31; along the feeding direction of the forward feeding during the forward sewing of the sewing machine, the detection points X of the seam thickness detection sensor 42 falling on the seam are distributed at the rear side of the outer presser foot 10 and the inner presser foot 20. The presser foot transmission mechanism has a transmission swing seat 61 rotatably supported in the sewing machine housing 31, i.e. the transmission swing seat 61 has a fixed rotation support point, and the angle of the transmission swing seat 61 determines the presser foot alternating amount. The alternating amount adjusting drive source 51 is installed on the sewing machine housing 31, and is connected with the transmission swing seat 61 through the alternating amount adjusting mechanism; when the alternating amount adjusting drive source 51 acts, the alternating amount adjusting drive source 51 drives the transmission swing seat 61 to rotate through an angle through the alternating amount adjusting mechanism, changes the angle of the transmission swing seat 61, changes the presser foot alternating amount of the sewing machine, and realizes the automatic adjustment of the presser foot alternating amount. The alternating amount detection sensor 43 is used for detecting the angle of the transmission swing seat 61, and further obtaining the presser foot alternating amount of the sewing machine. As shown in FIG. 12, the seam thickness detection sensor 42, the alternating amount adjusting drive source 51 and the alternating amount detection sensor 43 are all in communication connection with the control module 41.

[0075] In the above-mentioned fabric overlock detection sewing device, the real-time detection of the seam thickness is realized through the seam thickness detection sensor 42; and the oblique installation of the seam thickness detection sensor 42 at the bottom of the sewing machine housing 31 makes the detection points X of the seam thickness detection sensor 42 falling on the seam distributed at the rear side of the outer presser foot 10 and the inner presser foot 20, and when the sewing machine sews, the seam first passes through the detection points X of the seam thickness detection sensor 42, and then passes through the outer presser foot 10 and the inner presser foot 20, so that the seam thickness detected by the seam thickness detection sensor 42 is the thickness of the seam to be sewn, effectively realizing the advance detection of the seam thickness, and being able to detect and identify the height difference AH of the seam to be sewn in advance, so as to identify in advance the overlock sewing or the over-thick sewing to be sewn. On this premise, the control module 41 judges whether the presser foot alternating amount needs to be adjusted according to the comparison result of the identified height difference AH of the seam to be sewn and the presser foot alternating amount fed back by the alternating amount detection sensor 43; when it is judged that the presser foot alternating amount needs to be adjusted, the control module 41 sends an instruction to the alternating amount adjusting drive source 51, and the alternating amount adjusting drive source 51 acts to adjust the current presser foot alternating amount of the sewing machine to a target presser foot alternating amount.

[0076] Therefore, the sewing device for detecting the overlock has at least the following advantages: 1. By controlling the alternating amount to adjust the action of the driving source 51, the angle of the transmission swing seat 61 can be adjusted, and the automatic adjustment of the presser foot alternating amount is realized, without manual input in the whole process, and the degree of automation is high; 2. By the inclined installation of the sewing material thickness detection sensor 42, the detection point X is distributed on the rear side of the outer presser foot 10 and the inner presser foot 20, the advance detection of the sewing material thickness is effectively realized, the height difference of the sewing material to be sewn can be detected and identified in advance, so that the presser foot alternating amount of the sewing machine is adjusted in time, the presser foot alternating amount of the sewing machine is adapted to the change of the sewing material thickness, the efficiency is improved, the overlock stitch is beautified, and the sewing quality is ensured; 3. The advance detection of the sewing thickness is realized by the inclined installation of the sewing material thickness detection sensor 42 at the bottom of the sewing machine shell 31, without the need of complex additional devices, the advance real-time detection of the sewing material thickness can be realized, the operator's vision and operation space are not affected, the structure is simplified, the cost is reduced, and the installation and calibration are facilitated.

[0077] Further, the sewing material thickness detection sensor 42 is a laser displacement sensor. The principle of the laser displacement sensor for detecting the real-time thickness of the sewing material in advance is as follows: as shown in FIGS. 9 and 10, the laser displacement sensor has a laser emitter 421 and a light path structure sensor 422, the laser emitter 421 emits a laser to the sewing material at a fixed sensor inclination angle α, after the laser is reflected, the reflected light passes through the light path structure sensor 422, and then the light path structure sensor 422 can receive the reflected light source; when the thickness of the sewing material changes, the position of the reflected light source received by the light path structure sensor 422 is different, and thus the distance L from the laser displacement sensor to the sewing material is measured.

[0078] Therefore, the thickness H of the sewing material is: wherein L1 is the distance from the laser displacement sensor to the needle plate when there is no sewing material on the needle plate of the sewing machine; L 实时 is the distance from the laser displacement sensor to the sewing material when there is sewing material on the needle plate of the sewing machine.

[0079] In addition, the detection range of the thickness H of the sewing material is set to be within the following range: 0≤H≤Hmax; 0 is the value when there is no sewing material on the needle plate of the sewing machine, and 0 below represents the distance detected after the needle plate is removed; Hmax is the maximum detection thickness set. When the detected thickness H of the sewing material exceeds the range of 0-Hmax, the control module 41 judges that the data is an invalid parameter, so as to avoid the detection interference in the non-use scene.

[0080] Preferably, the outer presser foot 10 and the inner presser foot 20 are provided with needle holes for allowing the needle 38 of the sewing machine to penetrate. In the feeding direction of the forward feeding of the sewing machine during the forward sewing, the detection point X of the laser displacement sensor on the sewing material is aligned with the needle hole, so that the detection point X of the laser displacement sensor on the sewing material and the needle hole are in the same vertically extending plane, thereby effectively directly detecting the thickness of the position of the sewing material to be needle sewing under the premise of detecting the thickness of the sewing material in advance, and avoiding the interference caused by detecting the thickness of the sewing material at a non-sewing position.

[0081] Further, the present application detects the real-time thickness H of the sewing material to be sewn by the laser displacement sensor, to detect and identify the height difference AH of the sewing material to be sewn in advance, and judges whether the sewing material to be sewn is over-stitching or over-thickness, and whether the sewing material to be sewn is uphill sewing or downhill sewing when it is judged that the sewing material to be sewn is over-stitching or over-thickness. Specifically, as shown in FIG. 11a, before over-stitching or over-thickness identification, the laser displacement sensor detects the real-time thickness H1 of the sewing material to be sewn. When the sewing material to be sewn is over-stitching or over-thickness, as shown in FIG. 11b, the laser displacement sensor detects the real-time thickness H2 of the sewing material to be sewn. At this time, the height difference AH of the sewing material to be sewn is AH = H2 - H1, and H2 > H1, so it is judged that the sewing material to be sewn is over-stitching or over-thickness and uphill sewing. After over-stitching or over-thickness identification, as shown in FIG. 11c, the laser displacement sensor detects the real-time thickness H3 of the sewing material to be sewn. At this time, the height difference AH of the sewing material to be sewn is AH = H3 - H2, and H3 < H2, so it is judged that the sewing material to be sewn is downhill sewing after over-stitching or over-thickness.

[0082] Further, the preferred structure of the alternating amount adjusting mechanism is that, as shown in FIGS. 6 to 8, the alternating amount adjusting mechanism comprises an alternating amount adjusting shaft 52 rotatably supported in the sewing machine housing 31 through a shaft sleeve, and an alternating amount adjusting crank 53 fixed on the alternating amount adjusting shaft 52, the alternating amount adjusting driving source 51 is connected with the alternating amount adjusting crank 53 and is used to drive the alternating amount adjusting crank 53 to rotate, the left end of the alternating amount adjusting shaft 52 is fixed in the transmission swing seat 61, and the rotation axis of the alternating amount adjusting shaft 52 and the transmission swing seat 61 are collinear, so that the alternating amount adjusting shaft 52 constitutes the rotation fulcrum of the transmission swing seat 61. When the alternating amount adjusting driving source 51 drives the alternating amount adjusting crank 53 to rotate, the alternating amount adjusting shaft 52 and the transmission swing seat 61 rotate together by an angle, thereby changing the presser foot alternating amount of the sewing machine.

[0083] Preferably, based on the structure of the alternate amount adjusting mechanism, as shown in FIG. 6 and FIG. 7, the alternate amount detecting sensor 43 is a potentiometer connected to the right end of the alternate amount adjusting shaft 52. When the alternate amount adjusting shaft 52 rotates, the potentiometer shaft is driven to rotate, changing the resistance of the potentiometer. Different angles of the alternate amount adjusting shaft 52 correspond to different resistances of the potentiometer, and the angles of the alternate amount adjusting shaft 52 are one-to-one corresponding to the angles of the transmission swing base 61, and thus one-to-one corresponding to the alternate amount of the presser foot of the sewing machine. Therefore, the current angles of the alternate amount adjusting shaft 52 and the transmission swing base 61 can be identified through the potentiometer, and the current alternate amount of the presser foot of the sewing machine can be identified.

[0084] Further, the preferred structure of the presser foot transmission mechanism is as follows: as shown in FIG. 6 to FIG. 8, the presser foot transmission mechanism includes an alternate amount feeding eccentric wheel 62 fixed on the main shaft 32, an alternate amount feeding connecting rod 63, a first feeding connecting rod 64, a second feeding connecting rod 65, an upper crank shaft 66 rotatably supported in the sewing machine housing 31 through a shaft sleeve, an alternate amount lifting crank 67 fixed on the upper crank shaft 66, an upper feeding crank 68 fixed on the left end of the upper crank shaft 66, a presser foot feeding connecting rod 69, and a presser foot feeding connecting crank 610, one end of the alternate amount feeding connecting rod 63 is rotatably sleeved on the outer periphery of the alternate amount feeding eccentric wheel 62, the other end of the alternate amount feeding connecting rod 63, one end of the first feeding connecting rod 64, and one end of the second feeding connecting rod 65 are coaxially hinged, the other end of the first feeding connecting rod 64 is hinged with the transmission swing base 61, the other end of the second feeding connecting rod 65 is hinged with the alternate amount lifting crank 67, both ends of the presser foot feeding connecting rod 69 are respectively hinged with the upper feeding crank 68 and the presser foot feeding connecting crank 610, the upper end of the first presser foot rod 33 and the upper end of the second presser foot rod 34 are both hinged with the presser foot feeding connecting crank 610; and the hinged points of the presser foot feeding connecting crank 610 with the presser foot feeding connecting rod 69, the presser foot feeding connecting crank 610 with the first presser foot rod 33, and the presser foot feeding connecting crank 610 with the second presser foot rod 34 are in a triangular distribution. In this way, when the angle of the transmission swing base 61 changes, the transmission efficiency of the presser foot transmission mechanism changes, thereby changing the alternate amount of the presser foot of the sewing machine.

[0085] Further, the preferred structure of the presser foot transmission mechanism is as follows: as shown in FIG. 6 to FIG. 8, the presser foot transmission mechanism includes an alternate amount feeding eccentric wheel 62 fixed on the main shaft 32, an alternate amount feeding connecting rod 63, a first feeding connecting rod 64, a second feeding connecting rod 65, an upper crank shaft 66 rotatably supported in the sewing machine housing 31 through a shaft sleeve, an alternate amount lifting crank 67 fixed on the upper crank shaft 66, an upper feeding crank 68 fixed on the left end of the upper crank shaft 66, a presser foot feeding connecting rod 69, and a presser foot feeding connecting crank 610, one end of the alternate amount feeding connecting rod 63 is rotatably sleeved on the outer periphery of the alternate amount feeding eccentric wheel 62, the other end of the alternate amount feeding connecting rod 63, one end of the first feeding connecting rod 64, and one end of the second feeding connecting rod 65 are coaxially hinged, the other end of the first feeding connecting rod 64 is hinged with the transmission swing base 61, the other end of the second feeding connecting rod 65 is hinged with the alternate amount lifting crank 67, both ends of the presser foot feeding connecting rod 69 are respectively hinged with the upper feeding crank 68 and the presser foot feeding connecting crank 610, the upper end of the first presser foot rod 33 and the upper end of the second presser foot rod 34 are both hinged with the presser foot feeding connecting crank 610; and the hinged points of the presser foot feeding connecting crank 610 with the presser foot feeding connecting rod 69, the presser foot feeding connecting crank 610 with the first presser foot rod 33, and the presser foot feeding connecting crank 610 with the second presser foot rod 34 are in a triangular distribution. In this way, when the angle of the transmission swing base 61 changes, the transmission efficiency of the presser foot transmission mechanism changes, thereby changing the alternate amount of the presser foot of the sewing machine.

[0086] Further, as shown in FIGS. 6-8, the lifting tooth feeding mechanism has a lifting tooth shaft 81 and a feeding shaft 82, both of which are rotatably supported in the sewing machine base plate 39 through shaft sleeves; the left end of the lifting tooth shaft 81 is fixed with a lifting tooth crank 83, which is connected with the rear end of the tooth rack 35 through a lifting tooth connecting rod 84; the left end of the feeding shaft 82 is fixed with a feeding crank base 85, which is connected with the front end of the tooth rack 35 through a tooth rack pin 86. In particular, the fabric overlock detection sewing device further comprises a stitch length adjusting driving source 71 and a stitch length adjusting mechanism, the main shaft 32 is connected with the needle bar 37 through a fabric piercing driving mechanism, and the stitch length adjusting driving source 71 is connected with the lifting tooth feeding mechanism and the fabric piercing driving mechanism through the stitch length adjusting mechanism; the stitch length adjusting driving source 71 is preferably a motor and is fixed at the right end side of the sewing machine housing 31, and the stitch length adjusting driving source 71 is in communication connection with the control module 41. When the control module 41 controls the stitch length adjusting driving source 71 to act, the stitch length adjustment of the sewing machine is realized.

[0087] Further, the preferred structure of the stitch length adjusting mechanism is as follows: as shown in FIGS. 6-8, the stitch length adjusting mechanism comprises a stitch length adjusting frame 72 fixed on the motor shaft of the stitch length adjusting driving source 71, a stitch length adjusting pin 73 fixed on the stitch length adjusting frame 72, a stitch length adjusting base 74 rotatably supported in the sewing machine housing 31 through a shaft sleeve, a first stitch length adjusting connecting rod 75, a stitch length adjusting shaft 76 rotatably supported in the sewing machine base plate 39 through a shaft sleeve, a stitch length adjusting crank 77 and a stitch length adjusting swing base 78 both fixed on the stitch length adjusting shaft 76, a first feeding crank connecting rod 79, a second feeding crank connecting rod 710, a lower feeding connecting rod 711, a first lower feeding crank 712 and a second lower feeding crank 713 both fixed on the feeding shaft 82, a second stitch length adjusting connecting rod 714, a stitch length adjusting swing shaft 715 rotatably supported in the sewing machine housing 31 through a shaft sleeve, a stitch length adjusting swing crank 716 fixed at the right end of the stitch length adjusting swing shaft 715, and a stitch length adjusting swing frame 717 fixed at the left end of the stitch length adjusting swing shaft 715; the stitch length adjusting base 74 is provided with an adjusting groove, the stitch length adjusting pin 73 is located in the adjusting groove and in contact with the groove wall of the adjusting groove, the upper end and the lower end of the first stitch length adjusting connecting rod 75 are hingedly connected with the stitch length adjusting frame 72 and the stitch length adjusting crank 77 respectively, one end of the first feeding crank connecting rod 79, one end of the second feeding crank connecting rod 710, and one end of the lower feeding connecting rod 711 are coaxially hinged, the other end of the lower feeding connecting rod 711 is in transmission connection with the lifting tooth shaft 81, the other end of the first feeding crank connecting rod 79 is hingedly connected with the stitch length adjusting swing base 78, one end of the second feeding crank connecting rod 710 is hingedly connected with the first lower feeding crank 712, the lower end and the upper end of the second stitch length adjusting connecting rod 714 are hingedly connected with the second lower feeding crank 713 and the stitch length adjusting swing crank 716 respectively, and the second presser bar 34 and the needle bar 37 are both movably arranged in the stitch length adjusting swing frame 717.

[0088] Further, as shown in FIG. 12, the fabric overlock detection sewing device involved in the present application comprises a monitoring module, a control module 41 and an execution module. The monitoring module comprises a fabric thickness detection sensor 42 and an alternating amount detection sensor 43; and when the alternating amount adjusting driving source 51 and the stitch length adjusting driving source 71 are both motors, preferably step motors, the control module 41 can obtain the size of the presser foot alternating amount by obtaining the rotation angle of the alternating amount adjusting driving source 51, and obtain the size of the stitch length by obtaining the rotation angle of the stitch length adjusting driving source 71; at this time, the monitoring module further comprises a step control presser foot alternating amount structure and a step control stitch length structure. The control module 41 comprises a storage unit and an operation processing unit, and can receive and process feedback signals and perform corresponding operations, and then control the execution module accordingly. The execution module comprises the alternating amount adjusting driving source 51 and the stitch length adjusting driving source 71, and when the alternating amount adjusting driving source 51 is a step motor, it is a step adjustment control of the presser foot alternating amount; when the alternating amount adjusting driving source 51 is a cylinder or an electromagnet, it is a non-step adjustment control of the presser foot alternating amount.

[0089] Further, the present application also provides a fabric overlock detection sewing method using the above-mentioned fabric overlock detection sewing device. Based on the non-step adjustment control or step adjustment control of the presser foot alternating amount and whether the stitch length is adjusted during the presser foot alternating amount adjustment process, the fabric overlock detection sewing method has multiple embodiments. The following provides four preferred embodiments of the fabric overlock detection sewing method.

[0090] Fabric overlock detection sewing method embodiment one

[0091] In the fabric overlock detection sewing method embodiment one, the alternating amount adjusting driving source 51 is a cylinder or an electromagnet, so that the presser foot alternating amount of the sewing machine has two gears, a small presser foot alternating amount and a large presser foot alternating amount. The following describes the case where the alternating amount adjusting driving source 51 is a cylinder.

[0092] As shown in FIG. 13, the fabric overlock detection sewing method embodiment one is a non-step control of the presser foot alternating amount, which comprises the following steps in sequence:

[0093] S1, the sewing machine starts sewing, and the current presser foot alternating amount of the sewing machine is the small presser foot alternating amount;

[0094] S2, the fabric thickness detection sensor 42 detects the first real-time thickness of the fabric located at the rear side of the outer presser foot 10 and the inner presser foot 20, and feeds back the first real-time thickness to the control module 41, and the control module 41 obtains the height difference AH of the fabric to be sewn according to the first real-time thickness of the fabric, so as to realize the advance monitoring of the overlock sewing or the over-thickness sewing;

[0095] S3, the alternate amount detection sensor 43 detects the current angle of the transmission swing base 61 and feeds back the current angle to the control module 41, the control module 41 obtains the current presser foot alternate amount of the sewing machine according to the current angle of the transmission swing base 61, the current presser foot alternate amount has an alternate amount height value h, the control module 41 sets the current presser foot alternate amount as the initial presser foot alternate amount, the initial presser foot alternate amount is a small presser foot alternate amount;

[0096] S4, the control module 41 judges whether the absolute value of the height difference △H of the to-be-sewn fabric is greater than or equal to the alternate amount height value h of the current presser foot alternate amount: if not, the following step S5 is executed; if yes, the following step S6 is executed;

[0097] S5, return to the above step S2, and monitor again whether the over-thick sewing or the over-thin sewing is about to occur;

[0098] S6, the absolute value of the height difference △H of the to-be-sewn fabric is greater than or equal to the alternate amount height value h of the current presser foot alternate amount, the control module judges that the over-thick sewing or the over-thin sewing is about to occur; the over-thick sewing or the over-thin sewing involves the uphill sewing when the fabric thickness becomes large and the downhill sewing when the fabric thickness becomes small; at this time, the control module 41 judges whether the uphill sewing or the downhill sewing is about to occur according to the first real-time thickness of the fabric, and the specific judging method is described in the above part about FIG. 11b and FIG. 11c, that is, the current detected first fabric thickness > the previously detected fabric thickness, and the uphill sewing is judged; the current detected first fabric thickness < the previously detected fabric thickness, and the downhill sewing is judged

[0099] S7, when the control module 41 judges that the uphill sewing is about to occur, the following steps S71 to S74 are executed in turn:

[0100] S71, the control module 41 drives the alternate amount adjusting drive cylinder to act, the piston rod of the alternate amount adjusting drive cylinder is extended, the alternate amount adjusting drive cylinder drives the transmission swing base 61 to turn through an angle through the alternate amount adjusting mechanism, so that the presser foot alternate amount of the sewing machine becomes large, and the sewing machine has a large presser foot alternate amount;

[0101] S72, the control module 41 controls the sewing machine to run at a set needle number N, so that the outer presser foot 10 and the inner presser foot 20 can accurately go uphill under the condition of the large presser foot alternate amount, and the N should make the sewing machine complete the uphill action;

[0102] S73, the control module 41 reads the fabric thickness detection sensor 42 to obtain the second real-time thickness of the fabric located at the rear side of the outer presser foot 10 and the inner presser foot 20;

[0103] S74, the control module 41 judges whether the second real-time thickness of the fabric to be sewn is about to sew on a slope according to the second real-time thickness of the fabric to be sewn, the first real-time thickness of the fabric currently sewn, and the alternating amount height value h corresponding to the initial alternating amount of the presser foot. When the second real-time thickness is less than or equal to the first real-time thickness minus the alternating amount height value h corresponding to the initial alternating amount of the presser foot, it is judged that the fabric is not about to sew on a slope (no), and the above step S73 is returned. When the second real-time thickness is greater than the first real-time thickness minus the alternating amount height value h corresponding to the initial alternating amount of the presser foot, it is judged that the fabric is about to sew on a slope (yes), and the following step S82 is executed.

[0104] S8, when the control module 41 judges that the fabric is about to sew on a slope, the following steps S81 to S84 are executed in turn:

[0105] S81, the control module 41 drives the alternating amount adjusting drive cylinder to act, and the alternating amount adjusting drive cylinder drives the transmission swing seat 61 to swing through an angle through the alternating amount adjusting mechanism, so that the alternating amount of the presser foot of the sewing machine is increased, and the sewing machine has a large alternating amount of the presser foot.

[0106] S82, the control module 41 controls the sewing machine to run at a set number of stitches M, so that the outer presser foot 10 and the inner presser foot 20 can accurately sew on a slope under the condition of a large alternating amount of the presser foot, and M should make the sewing machine complete the action of sewing on a slope.

[0107] S83, the control module 41 drives the alternating amount adjusting drive cylinder to reset, and the piston rod of the alternating amount adjusting drive cylinder is retracted, so that the sewing machine returns to the current alternating amount of the presser foot in the above step S3, which is a small alternating amount of the presser foot.

[0108] S84, return to the above step S2.

[0109] Therefore, when the control module 41 judges that the fabric is about to sew on a slope or sew on a thick seam, the electric control module controls the alternating amount of the presser foot of the sewing machine to be large, whether it is sewing on a slope or sewing on a slope. When the real-time thickness of the fabric is detected in advance, the alternating amount of the presser foot of the sewing machine is increased in advance when the fabric is detected in advance, and the fabric is moved forward to the outer presser foot 10 and the inner presser foot 20 when the fabric is thick. When the thickness of the fabric is large, the sewing machine has a large alternating amount of the presser foot, so that the sewing machine can smoothly complete the sewing of the thick seam.

[0110] Fabric over-gang detection sewing method embodiment two

[0111] The difference between the second embodiment of the fabric overfeed detection sewing method and the first embodiment of the fabric overfeed detection sewing method is that in the second embodiment of the fabric overfeed detection sewing method, the alternating amount adjusting driving source 51 is a motor, the presser foot alternating amount of the sewing machine has at least two gears, and the motor shaft of the alternating amount adjusting driving source 51 rotates through different angles to drive the transmission swing seat 61 to different angles, thereby making the sewing machine have multiple presser foot alternating amounts of different sizes.

[0112] As shown in FIG. 14, the second embodiment of the fabric overfeed detection sewing method is a step control presser foot alternating amount, which sequentially includes the following steps:

[0113] S1, the sewing machine starts sewing, and the current presser foot alternating amount of the sewing machine is a small presser foot alternating amount;

[0114] S2, the fabric thickness detection sensor 42 detects the first real-time thickness of the fabric located at the rear side of the outer presser foot 10 and the inner presser foot 20, and feeds back the first real-time thickness to the control module 41, and the control module 41 obtains the height difference △H of the fabric to be sewn according to the first real-time thickness of the fabric, thereby realizing the advance monitoring of overfeed sewing or over-thickness sewing;

[0115] S3, the alternating amount detection sensor 43 detects the current angle of the transmission swing seat 61, and feeds back the current angle to the control module 41, and the control module 41 obtains the current presser foot alternating amount of the sewing machine according to the current angle of the transmission swing seat 61, and the current presser foot alternating amount has an alternating amount height value h, and the control module 41 sets the current presser foot alternating amount as the initial presser foot alternating amount, and the initial presser foot alternating amount is a small presser foot alternating amount;

[0116] S4, the control module 41 judges whether the absolute value of the height difference △H of the fabric to be sewn is greater than or equal to the alternating amount height value h of the current presser foot alternating amount: if not, step S5 is executed; if yes, step S6 is executed;

[0117] S5, return to step S2 above, and monitor again whether overfeed sewing or over-thickness sewing is about to occur;

[0118] S6, the absolute value of the height difference △H of the fabric to be sewn is greater than or equal to the alternating amount height value h of the current presser foot alternating amount, and the control module judges that overfeed sewing or over-thickness sewing is about to occur; at this time, the control module 41 judges whether uphill sewing or downhill sewing is about to occur according to the first real-time thickness of the fabric;

[0119] S7, when the control module 41 judges that uphill sewing is about to occur, steps S71 to S74 are sequentially executed:

[0120] S71, the control module 41 drives the alternating amount adjusting drive motor to act, the motor shaft of the alternating amount adjusting drive motor rotates through the target angle, the alternating amount adjusting drive motor drives the transmission swing seat 61 through the alternating amount adjusting mechanism to rotate through an angle, so that the presser foot of the sewing machine has a large alternating amount, and the sewing machine has a large alternating amount of the presser foot; the control logic of the presser foot alternating amount is: the alternating amount height value h of the adjusted presser foot alternating amount = the absolute value of the height difference △H of the to-be-sewn sewing material + the compensation height parameter h1, to avoid the problem of accelerated wear of parts due to the too large alternating amount of the presser foot;

[0121] S72, the control module 41 reads the sewing material thickness detection sensor 42 to obtain the second real-time thickness of the sewing material located at the rear side of the outer presser foot 10 and the inner presser foot 20;

[0122] S73, the control module 41 drives the alternating amount adjusting drive motor to reset, and the sewing machine restores the current presser foot alternating amount in the above step S3, which is a small presser foot alternating amount;

[0123] S74, the control module 41 judges whether it is to sew downhill after uphill according to the second real-time thickness of the to-be-sewn sewing material, the first real-time thickness of the current sewing sewing material, and the alternating amount height value h corresponding to the initial presser foot alternating amount: if not, return to the above step S73; if yes, execute the following step S82;

[0124] S8, when the control module 41 judges that it is to sew downhill, the following steps S81 to S84 are executed in turn:

[0125] S81, the control module 41 drives the alternating amount adjusting drive motor to act, the alternating amount adjusting drive motor drives the transmission swing seat 61 through the alternating amount adjusting mechanism to rotate through an angle, so that the presser foot of the sewing machine has a large alternating amount, and the sewing machine has a large alternating amount of the presser foot;

[0126] S82, the control module 41 controls the sewing machine to run a set number of needles M, so that the outer presser foot 10 and the inner presser foot 20 can accurately go downhill, and M should make the sewing machine complete the action of going downhill;

[0127] S83, the control module 41 drives the alternating amount adjusting drive motor to reset, and the sewing machine restores the current presser foot alternating amount in the above step S3, which is a small presser foot alternating amount;

[0128] S84, return to the above step S2.

[0129] In the above-mentioned first and second fabric overlock detection sewing method embodiments, the needle pitch of the sewing machine remains unchanged during the adjustment of the alternate amount of the presser foot. In this way, the distance between the needle 38 and the position of the change in fabric thickness is random for the previous stitch of overlock sewing or the previous stitch of overthickness sewing, and it is very likely that the needle 38 does not just puncture in front of the position of the overlock when the previous stitch of overlock sewing or the previous stitch of overthickness sewing occurs, as shown in FIG. 17. Since the overlock position has a certain height, a large gap will be formed in front of the overlock position for this stitch, as shown in FIG. 18, thereby causing the thread take-up of this stitch to be loose, which easily forms a poor stitch. Based on this, in the third and fourth fabric overlock detection sewing method embodiments described below, the needle pitch of the sewing machine is adjusted at the same time during the adjustment of the alternate amount of the presser foot, so that the needle 38 just punctures in front of the position of the overlock for the previous stitch of overlock sewing or the previous stitch of overthickness sewing, thereby optimizing the stitch during uphill sewing.

[0130] Third fabric overlock detection sewing method embodiment

[0131] As shown in FIG. 15, the third fabric overlock detection sewing method embodiment is improved based on the first fabric overlock detection sewing method embodiment, and specifically optimizes the step S72 involved in the first fabric overlock detection sewing method embodiment, so that the step S72 is performed in the following sub-steps:

[0132] S721, the control module 41 acquires a target needle pitch according to the installation data of the fabric thickness detection sensor 42 and the detection data of the fabric thickness detection sensor 42;

[0133] S722, the control module 41 drives the needle pitch adjustment driving source 71 to act on the lift tooth feeding mechanism and the fabric penetrating driving mechanism through the needle pitch adjustment mechanism, so as to adjust the needle pitch of the sewing machine from the current needle pitch to the target needle pitch;

[0134] S723, the control module 41 controls the sewing machine to run for a set number N of stitches at the target needle pitch, so that the needle 38 just punctures in front of the position of the overlock for the previous stitch of overlock sewing or the previous stitch of overthickness sewing;

[0135] S724, the control module 41 drives the needle pitch adjustment driving source 71 to reset, so as to restore the needle pitch of the sewing machine from the target needle pitch to the current needle pitch before the adjustment of the needle pitch;

[0136] S725, the control module 41 controls the sewing machine to run for a set number N+1 of stitches at the current needle pitch, so as to ensure that the outer presser foot 10 and the inner presser foot 20 have passed the overlock.

[0137] Fourth fabric overlock detection sewing method embodiment

[0138] As shown in FIG. 16, the fabric over-bat detection sewing method embodiment four is improved on the basis of the fabric over-bat detection sewing method embodiment two, and specifically, the step S72 involved in the fabric over-bat detection sewing method embodiment two is optimized, so that the step S72 is executed in the following sub-steps:

[0139] S721, the control module 41 obtains the target stitch length according to the installation data of the fabric thickness detection sensor 42 and the detection data of the fabric thickness detection sensor 42;

[0140] S722, the control module 41 drives the stitch length adjustment driving source 71 to act, and the stitch length adjustment driving source 71 acts on the needle lifting feeding mechanism and the fabric penetrating driving mechanism through the stitch length adjustment mechanism, so as to adjust the stitch length of the sewing machine from the current stitch length to the target stitch length;

[0141] S723, the control module 41 controls the sewing machine to run for a set number N of stitches at the target stitch length, so that the needle 38 of the previous stitch of over-bat sewing or the previous stitch of over-thickness sewing is just in front of the bat part;

[0142] S724, the control module 41 drives the stitch length adjustment driving source 71 to reset, so as to restore the stitch length of the sewing machine from the target stitch length to the current stitch length before the stitch length adjustment;

[0143] S725, the control module 41 controls the sewing machine to run for a set number N+1 of stitches at the current stitch length, so as to ensure that the outer presser foot 10 and the inner presser foot 20 have passed the bat.

[0144] Further, in the fabric over-bat detection sewing method embodiment three and the fabric over-bat detection sewing method embodiment four, the control principle for ensuring that the needle 38 of the previous stitch of over-bat sewing or the previous stitch of over-thickness sewing is just in front of the bat part by adjusting the stitch length of the sewing machine to the target stitch length is as follows: as shown in FIG. 19, when the fabric thickness detection sensor 42 detects the bat part, the distance between the fabric thickness detection sensor 42 and the bat part is Lg; the distance between the fabric thickness detection sensor 42 and the center of the needle bar 37 is A, which is determined by the installation position of the fabric thickness detection sensor 42; then the interval B between the needle 38 and the bat part in the front-back direction is B=A+Lg×cosα. Then, the target stitch number K1 is calculated as K1=B÷P1, P1 being the current stitch length of the sewing machine; the target stitch number K1 is rounded to the target running stitch number K2, and then the target stitch length P2 is P2=B÷K2. In this way, the needle 38 of the previous stitch of over-bat sewing or the previous stitch of over-thickness sewing is reliably ensured to be just in front of the bat part, as shown in FIG. 20, effectively avoiding the formation of a large gap in front of the bat part, so that the stitch is effectively tightened.

[0145] In summary, the present application has the following advantages.

[0146] 1. Early detection of seam thickness changes: The use of a laser displacement sensor allows for early detection of seam thickness, avoiding detection lag and improving sewing quality. At the same time, the laser displacement sensor can accurately identify changes in seam thickness, ensuring that the sewing machine adjusts in time when encountering thick or thin materials, maintaining smooth and uniform sewing.

[0147] 2. Automatic adjustment of presser foot alternation: The control module 41 automatically identifies the height difference of the stitch area and adjusts the presser foot alternation, eliminating the need for manual input and improving operational efficiency and accuracy. The lifting height of the outer presser foot 10 and the inner presser foot 20 can be automatically adjusted according to the thickness of the fabric, avoiding the hassle of frequent operator adjustments and ensuring that the sewing machine maintains optimal performance on various fabrics.

[0148] 3. Simplified structural design: Real-time detection of seam thickness is achieved without the need for complex additional devices, reducing manufacturing and maintenance costs. The overall design is simple and efficient, not only reducing production costs but also reducing equipment maintenance workload, making the sewing machine more economical and practical.

[0149] 4. Improve sewing efficiency and quality: Through the use of stepper motors and air cylinders as execution devices, the presser foot alternation and stitch length are precisely controlled, ensuring smooth sewing and beautiful stitches, reducing waste. The precise control system can adjust sewing parameters as needed to ensure optimal sewing results in various sewing scenarios.

[0150] 5. Improve operator experience: Reducing the need for operators to frequently adjust the alternation amount button reduces operator fatigue and improves work efficiency and sewing quality. The automatic adjustment function eliminates the need for frequent manual adjustments, reducing operational difficulty and fatigue, and improving overall production efficiency and product quality.

[0151] 6. Adaptive adjustment: During the sewing process, the presser foot alternation is automatically adjusted according to actual needs to adapt to different thicknesses and types of fabric, ensuring the continuity and stability of the sewing process. The system can adapt to changes in fabric thickness, automatically optimizing sewing parameters to ensure stability and consistency in the sewing process, suitable for a variety of complex sewing tasks.

[0152] 7. Reduce failures and improve reliability: Automatic adjustment of presser foot alternation avoids problems such as fabric jamming, uneven stitches, or broken needles caused by improper manual adjustment, improving the reliability and durability of the sewing machine. Through precise automatic control systems, human operational errors are reduced, ensuring stable operation of the equipment and extending the service life of the equipment.

[0153] 8. Reduce noise and part wear: Precise control of the alternating height of the presser foot avoids excessive adjustment, reduces noise and part wear during operation, and prolongs the service life of the sewing machine; the automatic adjustment mechanism reduces the impact on mechanical parts, reduces noise and wear, and maintains the long-term stability of the equipment.

[0154] 9. Improve production efficiency: High automation reduces manual intervention and adjustment time, improves overall production efficiency, especially suitable for high-intensity production environment, realizes more efficient production process; automatic adjustment and real-time detection function greatly improves the operation efficiency of the production line, adapts to the demand of modern large-scale production, improves the production capacity and competitiveness of enterprises.

[0155] In summary, the present application effectively overcomes the shortcomings of the prior art and has high industrial utilization value.

[0156] The above examples only illustrate the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea disclosed by the present application shall be covered by the claims of the present application.

Claims

1. A fabric overlock detection sewing apparatus comprising a main shaft (32) rotatably supported in a sewing machine housing (31), a first presser bar (33) and a second presser bar (34) both movably fitted in said sewing machine housing (31), an outer presser foot (10) mounted at a lower end of said first presser bar (33), an inner presser foot (20) mounted at a lower end of said second presser bar (34), and a presser foot drive mechanism, said main shaft (32) being connected to said first presser bar (33) and said second presser bar (34) through said presser foot drive mechanism, characterized in that: The control module (41), the fabric thickness detection sensor (42), the alternating amount adjusting mechanism, the alternating amount detection sensor (43), and the alternating amount adjusting drive source (51) installed on the sewing machine housing (31) are also included. The fabric thickness detection sensor (42) is obliquely installed on the bottom of the sewing machine housing (31); along the feeding direction of the forward feeding during the forward sewing of the sewing machine, the detection points of the fabric thickness detection sensor (42) on the fabric are distributed on the rear side of the outer presser foot (10) and the inner presser foot (20). The presser foot driving mechanism has a driving swing base (61) rotatably supported in the sewing machine housing (31); the angle of the driving swing base (61) determines the alternating amount of the presser foot; the alternating amount adjusting drive source (51) is connected to the driving swing base (61) through the alternating amount adjusting mechanism; and the alternating amount detection sensor (43) is used to detect the angle of the driving swing base (61). The fabric thickness detection sensor (42), the alternating amount adjusting drive source (51), and the alternating amount detection sensor (43) are all communicatively connected to the control module (41).

2. The fabric underlap detection sewing apparatus according to claim 1, wherein: The fabric thickness detection sensor (42) is a laser displacement sensor.

3. The fabric thread break detection sewing apparatus according to claim 1 or 2, characterized by: The outer presser foot (10) and the inner presser foot (20) are both provided with needle holes allowing the needle (38) in the sewing machine to pierce; Along the feeding direction of the forward feeding during the forward sewing of the sewing machine, the detection points of the fabric thickness detection sensor (42) on the fabric are aligned with the needle holes.

4. The fabric underlap detection sewing apparatus according to claim 1, wherein: The alternating amount adjusting mechanism includes an alternating amount adjusting shaft (52) rotatably supported in the sewing machine housing (31), and an alternating amount adjusting crank (53) fixed on the alternating amount adjusting shaft (52); the alternating amount adjusting drive source (51) is connected to the alternating amount adjusting crank (53) and is used to drive the rotation of the alternating amount adjusting crank (53); one end of the alternating amount adjusting shaft (52) is fixed to the driving swing base (61); and the rotation axis of the alternating amount adjusting shaft (52) is collinear with that of the driving swing base (61).

5. The fabric thread break detection sewing apparatus according to claim 4, wherein: The alternating amount detection sensor (43) is a potentiometer connected to the other end of the alternating amount adjusting shaft (52).

6. The fabric thread break detection sewing apparatus according to claim 1, wherein: The presser foot driving mechanism comprises an alternate amount feeding eccentric wheel (62) fixed on the main shaft (32), an alternate amount feeding connecting rod (63), a first feeding connecting rod (64), a second feeding connecting rod (65), an upper crank shaft (66) rotatably supported in the sewing machine housing (31), an alternate amount lifting crank (67) and an upper feeding crank (68) both fixed on the upper crank shaft (66), a presser foot feeding connecting rod (69), and a presser foot feeding connecting crank (610), one end of the alternate amount feeding connecting rod (63) is rotatably sleeved on the outer periphery of the alternate amount feeding eccentric wheel (62), the other end of the alternate amount feeding connecting rod (63), one end of the first feeding connecting rod (64), and one end of the second feeding connecting rod (65) are coaxially hinged, the other end of the first feeding connecting rod (64) is hinged with the driving swing seat (61), the other end of the second feeding connecting rod (65) is hinged with the alternate amount lifting crank (67), the two ends of the presser foot feeding connecting rod (69) are respectively hinged with the upper feeding crank (68) and the presser foot feeding connecting crank (610), the first presser foot rod (33) and the second presser foot rod (34) are both hinged with the presser foot feeding connecting crank (610), the hinged points of the presser foot feeding connecting crank (610) with the presser foot feeding connecting rod (69), the hinged points of the presser foot feeding connecting crank (610) with the first presser foot rod (33), and the hinged points of the presser foot feeding connecting crank (610) with the second presser foot rod (34) are in a triangular distribution.

7. A sewing method for detecting a fabric overlock, characterized by: The fabric overlock detection sewing device of any one of claims 1-6, the fabric overlock detection sewing method comprising the steps of: S1, the sewing machine starts sewing; S2, the fabric thickness detection sensor (42) detects the first real-time thickness of the fabric located behind the outer presser foot (10) and the inner presser foot (20), and feeds the first real-time thickness to the control module (41), the control module (41) obtains the height difference △H of the fabric to be sewn according to the first real-time thickness of the fabric; S3, the alternate amount detection sensor (43) detects the current angle of the driving swing seat (61) and feeds the current angle to the control module (41), the control module (41) obtains the current presser foot alternate amount of the sewing machine according to the current angle of the driving swing seat (61), the current presser foot alternate amount has an alternate amount height value h, and the control module (41) sets the current presser foot alternate amount as the initial presser foot alternate amount; S4, the control module (41) judges whether the absolute value of the height difference △H of the fabric to be sewn is greater than or equal to the alternate amount height value h of the current presser foot alternate amount: if not, step S5 is executed; if yes, step S6 is executed; S5, return to step S2; S6, the control module (41) judges whether to uphill sew or downhill sew according to the real-time thickness of the fabric; S7, the control module (41) judges to uphill sew, and sequentially executes steps S71-S74: S71, the control module (41) drives the alternate amount adjusting driving source (51) to act, the alternate amount adjusting driving source (51) drives the transmission swing seat (61) to rotate through the alternate amount adjusting mechanism, makes the presser foot of sewing machine alternate amount variable; S72, the control module (41) controls the running set needle number of sewing machine; S73, the control module (41) reads the sewing material thickness detection sensor (42), obtains the second real-time thickness of the sewing material located at the rear side of the outer presser foot (10) and the inner presser foot (20); S74, the control module (41) judges whether it will downhill according to the second real-time thickness of the sewing material, the first real-time thickness and the alternate amount height value h corresponding to the initial presser foot alternate amount, if not, return to the above step S73, if yes, execute the following step S82; S8, the control module (41) judges to downhill sewing, executes the following steps S81 to S84 in turn: S81, the control module (41) drives the alternate amount adjusting driving source (51) to act, the alternate amount adjusting driving source (51) drives the transmission swing seat (61) to rotate through the alternate amount adjusting mechanism, makes the presser foot of sewing machine alternate amount variable; S82, the control module (41) controls the running set needle number of sewing machine; S83, the control module (41) drives the alternate amount adjusting driving source (51) to reset, and the sewing machine restores the current presser foot alternate amount in the above step S3; S84, return to the above step S2.

8. The fabric thread break detection sewing method according to claim 7, characterized by: The alternate amount adjusting driving source (51) is a cylinder or an electromagnet, and the presser foot alternate amount of the sewing machine has two gears.

9. The fabric thread break detection sewing method according to claim 7, characterized by: The alternate amount adjusting driving source (51) is a motor, and the presser foot alternate amount of the sewing machine has at least two gears.

10. The fabric-to-fabric detection sewing method according to any one of claims 7-9, wherein: The fabric overlock detection sewing device further comprises a tooth frame (35), a feeding tooth (36) fixed on the tooth frame (35), a tooth lifting feeding mechanism connected with the tooth frame (35), a needle bar (37) movably assembled in the sewing machine housing (31), a needle (38) installed at the lower end of the needle bar (37), a fabric piercing driving mechanism, a stitch spacing adjusting driving source (71), and a stitch spacing adjusting mechanism, the main shaft (32) is connected with the needle bar (37) through the fabric piercing driving mechanism, the stitch spacing adjusting driving source (71) is connected with the tooth lifting feeding mechanism and the fabric piercing driving mechanism through the stitch spacing adjusting mechanism, and the stitch spacing adjusting driving source (71) is in communication connection with the control module (41). The step S72 in the fabric overlock detection sewing method is executed in the following steps: S721, the control module (41) obtains the target needle spacing according to the installation data of the sewing material thickness detection sensor (42) and the detection data of the sewing material thickness detection sensor (42); S722, the control module (41) drives the stitch spacing adjusting driving source (71) to act, the stitch spacing adjusting driving source (71) acts on the tooth lifting feeding mechanism and the fabric piercing driving mechanism through the stitch spacing adjusting mechanism, and adjusts the needle spacing of the sewing machine from the current needle spacing to the target needle spacing; S723, the control module (41) controls the sewing machine to run the set needle number at the target needle spacing; S724, the control module (41) drives the needle spacing adjustment driving source (71) to reset, and restores the needle spacing of the sewing machine from the target needle spacing to the current needle spacing before the needle spacing adjustment; S725, the control module (41) controls the sewing machine to run a set number of stitches at the current needle spacing.

11. The fabric stitch detection sewing method according to claim 10, wherein: The lift pin feeding mechanism has a lift pin shaft (81) and a feeding shaft (82) which are rotatably supported in the sewing machine base plate (39); The needle spacing adjustment driving source (71) is a motor; the needle spacing adjustment mechanism comprises a needle spacing adjustment frame (72) driven to rotate by the needle spacing adjustment driving source (71), a needle spacing adjustment pin (73) fixed to the needle spacing adjustment frame (72), a needle spacing adjustment seat (74) rotatably supported in the sewing machine housing (31), a first needle spacing adjustment connecting rod (75), a needle spacing adjustment shaft (76) rotatably supported in the sewing machine base plate (39), a needle spacing adjustment crank (77) and a needle spacing adjustment swing seat (78) both fixed on the needle spacing adjustment shaft (76), a first feeding crank connecting rod (79), a second feeding crank connecting rod (710), a lower feeding connecting rod (711), a first lower feeding crank (712) and a second lower feeding crank (713) both fixed on the feeding shaft (82), a second needle spacing adjustment connecting rod (714), a needle spacing adjustment swing shaft (715) rotatably supported in the sewing machine housing (31), and a needle spacing adjustment swing crank (716) and a needle spacing adjustment swing frame (717) both fixed on the needle spacing adjustment swing shaft (715), the needle spacing adjustment seat (74) is provided with an adjustment groove, the needle spacing adjustment pin (73) is located in the adjustment groove and in contact with the groove wall of the adjustment groove, both ends of the first needle spacing adjustment connecting rod (75) are hingedly connected with the needle spacing adjustment frame (72) and the needle spacing adjustment crank (77), one end of the first feeding crank connecting rod (79), one end of the second feeding crank connecting rod (710), and one end of the lower feeding connecting rod (711) are coaxially hinged, the other end of the lower feeding connecting rod (711) is in transmission connection with the lift pin shaft (81), the other end of the first feeding crank connecting rod (79) is hingedly connected with the needle spacing adjustment swing seat (78), one end of the second feeding crank connecting rod (710) is hingedly connected with the first lower feeding crank (712), both ends of the second needle spacing adjustment connecting rod (714) are hingedly connected with the second lower feeding crank (713) and the needle spacing adjustment swing crank (716), and the second presser bar (34) and the needle bar (37) are movably arranged in the needle spacing adjustment swing frame (717).

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