Cloth thickness detection method and system, thread supply quantity control method and sewing machine

Abstract

The invention discloses a cloth thickness detection method and system, a thread supply quantity control method and a sewing machine, and relates to the technical field of sewing machines, and the cloth thickness detection method comprises the steps: obtaining a time interval T of a time point when a machine needle passes through a stroke calibration point and a time point when the machine needle pierces the outer surface of cloth; the displacement H of the machine needle in the T is obtained; obtaining the distance H0 between the stroke calibration point and the needle plate; calculating the thickness H of the cloth according to the H0 and the H; according to the cloth thickness detection method and system, the thread supply quantity control method and the sewing machine, the thickness of the cloth is measured in an indirect measurement and calculation mode, the influence of different cloth types and different cloth compression conditions on the sewing thickness of the cloth is reduced, and parameters of the sewing machine are conveniently and accurately adjusted so as to guarantee the sewing effect.

Description

Technical Field

[0001] The present invention relates to the technical field of sewing machines, and more particularly to a cloth thickness detection method and system, a thread supply control method and a sewing machine. Background Art

[0002] Fabrics of varying thicknesses significantly impact the performance, accessories, and operating techniques of a sewing machine. Thicker fabrics require greater adaptation to the machine's performance by increasing penetration (thicker needles), enhancing grip (lifting the material), and reducing friction (rollers / lubricants). However, in many sewing scenarios, a single sewing machine cycle often involves sewing multiple fabrics of varying thicknesses. The process of passing through thick layers, hard objects, or raised areas (such as overlapping layers, seams, buttons, zippers, and decorative accessories) is known as "passing."

[0003] The main reason why threading is such a challenge in the sewing industry is that different fabrics have significantly different thicknesses (for example, thin tulle can be only 0.1mm, while thick denim can reach over 2mm). Furthermore, multiple layers are often stacked on the same workpiece (for example, pockets on clothing or the seams of luggage may contain over 5 layers of fabric), resulting in sudden changes in thickness that can be several times or even more than ten times. Sewing machines need to adapt to these changes in a very short time, and traditional mechanical structures struggle to respond in real time. Key parameters such as presser foot pressure, feed dog height, and stitch length require manual adjustment and cannot be dynamically adjusted during the sewing process. These sudden changes in thickness can lead to mismatched card clothing and mismatched pressing force due to the material presser height, affecting sewing performance and causing thread breakage, skipped stitches, and uneven seams.

[0004] In the prior art, there are methods for directly detecting the thickness of the fabric through contact or non-contact means, and then adjusting the driving parameters of the sewing machine to improve the sewing effect of the sewing machine. However, the existing methods for measuring the thickness of the fabric are all direct measurements of the thickness of the fabric. However, when the fabric is sewn, there is a compression variable, that is, when the fabric is not compressed, its thickness is significantly greater than the thickness after compression. Similarly, for fabrics of different densities, such as yarn and denim, the thickness of uncompressed fabrics of the same thickness is still different under the same compression force after compression. Moreover, there is a large difference in the resistance of fabrics of different densities when inserting the needle and thread, so there is a big difference in the adjustment of the sewing parameters of the sewing machine.

[0005] In summary, how to solve the impact of different fabric types and fabric compression conditions on the fabric sewing thickness detection results and the impact on sewing machine parameter adjustment is a problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for detecting the thickness of the fabric, which uses indirect measurement and calculation to measure the thickness of the fabric, reduce the influence of different fabric types and fabric compression conditions on the thickness of the fabric involved in sewing, and facilitate precise adjustment of the parameters of the sewing machine to ensure the sewing effect.

[0007] A second object of the present invention is to provide a cloth thickness detection system for applying the above-mentioned cloth thickness detection method, which has the same technical features and can solve the same technical problems.

[0008] The third object of the present invention is to provide a thread supply control method including the above-mentioned fabric thickness detection method, by detecting the thickness of the fabric involved in sewing, adjusting the single thread supply amount of the thread supply module in the sewing machine to improve the final sewing effect.

[0009] A fourth object of the present invention is to provide a sewing machine comprising the above-mentioned fabric thickness detection system, and / or for applying the above-mentioned fabric thickness detection method and / or thread supply control method, which has the same technical features and can solve the same technical problems.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] A fabric thickness detection method for detecting the thickness of fabric sewn by a sewing machine needle;

[0012] Fabric thickness detection method, including:

[0013] Obtain the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric;

[0014] Get the needle displacement △H within △T and the distance H0 between the stroke calibration point and the needle plate;

[0015] The fabric thickness H is calculated using H0 and △H.

[0016] Preferably, the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained includes:

[0017] Get the tension of sewing thread when the needle moves;

[0018] Obtain the time zone T1 between the time point when the sewing thread tension first changes suddenly and the time point when the needle passes the stroke calibration point within a single movement cycle of the needle, and assign T1 to △T.

[0019] Preferably, the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained includes:

[0020] The end point of the needle stroke on the outer surface of the fabric is taken as the stroke calibration point;

[0021] The calculation of the fabric thickness H using H0 and ΔH includes:

[0022] Calculate the fabric thickness H=H0-△H.

[0023] Preferably, the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained includes:

[0024] The end point of the needle stroke on the inner surface of the fabric is taken as the stroke calibration point;

[0025] The calculation of the fabric thickness H using H0 and ΔH includes:

[0026] Calculate the fabric thickness H=△H-H0.

[0027] A cloth thickness detection system, for implementing any one of the cloth thickness detection methods described above, comprising:

[0028] A time acquisition module, used to obtain the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when it pierces the outer surface of the fabric;

[0029] A stroke acquisition module is used to calculate and obtain the needle displacement △H within △T, and / or obtain the distance H0 between the stroke calibration point and the needle plate;

[0030] The calculation module is used to calculate the thickness H of the fabric through H0 and △H.

[0031] A thread supply control method for controlling the single thread supply amount of a thread supply module in a sewing machine;

[0032] The wire supply quantity control method includes:

[0033] Obtaining the thickness H of the fabric sewn during the current needle stroke cycle according to any one of the fabric thickness detection methods described above;

[0034] Determine whether the fabric thickness Hn in the current stroke cycle is greater than the fabric thickness Hm in the previous stroke cycle;

[0035] If yes, control the wire supply module to increase the single wire supply amount;

[0036] If not, determine whether the fabric thickness Hn in the current stroke cycle is less than the fabric thickness Hm in the previous stroke cycle;

[0037] If yes, control the wire supply module to reduce the single wire supply amount;

[0038] If not, the wire supply module is controlled to maintain the current single wire supply amount.

[0039] Preferably, the control line supply module increases the single line supply amount, including:

[0040] The increase in the single wire supply amount is 2*(Hn-Hm).

[0041] Preferably, the control line supply module reduces the single line supply amount, including:

[0042] The reduction in the single wire supply amount is 2*(Hm-Hn).

[0043] A sewing machine, used to implement any one of the above-mentioned methods for detecting fabric thickness.

[0044] A sewing machine, used to implement any one of the above-mentioned thread supply control methods, comprises a thread supply module.

[0045] Compared with the prior art, the fabric thickness detection method provided by the present invention has at least the following beneficial effects:

[0046] 1. Obtain the time interval △T between the time when the needle passes through the stroke calibration point and the time when the needle passes through the upper surface of the fabric, and calculate the needle displacement △H within △T. Combined with the distance H0 between the stroke calibration point and the needle plate, the thickness of the fabric is calculated;

[0047] Since the distance H0 between the stroke calibration point and the needle plate is constant, and the displacement of the needle per unit time after passing the stroke calibration point can be directly obtained through the existing displacement calculation formula, and there is only one variable △T in the entire calculation process, therefore, only one variable △T needs to be measured to calculate the fabric thickness, reducing the difficulty of fabric thickness detection.

[0048] 2. By detecting the time interval △T between the time point when the needle passes through the stroke calibration point and the time point when the needle passes through the upper surface of the fabric, the fabric thickness can be indirectly obtained. In the process, the last node of the time interval is the time when the needle passes through the upper surface of the fabric. Before passing through the fabric, the needle will preliminarily compress the fabric. When the compression resistance is greater than the puncture resistance of the needle, the needle can pierce the fabric. Therefore, there is a fixed proportional relationship between the fabric thickness measured by this method and the effective thickness of the fabric involved in sewing. It is not affected by the pre-compression of the fabric and the density of the fabric material, which is convenient for precise control of the parameters of the sewing machine to ensure the sewing effect.

[0049] The cloth thickness detection system provided by the present invention is used to apply the above-mentioned cloth thickness detection method and has the same beneficial effects.

[0050] The thread supply control method provided by the present invention includes the above-mentioned fabric thickness detection method, which can obtain the effective thickness of the fabric involved in sewing, that is, the actual thickness of the fabric at the sewing position after the sewing thread and the bottom thread are hooked and tightened. According to the stitch width of the machine needle, the current optimal single thread supply of the thread supply module can be calculated, so as to accurately control the single thread supply of the thread supply module to improve the final sewing effect.

[0051] The sewing machine provided by the present invention includes the above-mentioned fabric thickness detection system and / or is used to apply the above-mentioned fabric thickness detection method and / or thread supply control method, and has the same beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0053] Figure 1 This is a schematic diagram of detection data provided by the present invention when point A in the figure is used as the travel calibration point;

[0054] Figure 2 This is a schematic diagram of the detection data provided by the present invention when point B in the figure is used as the travel calibration point;

[0055] Figure 3 This is a schematic diagram of the detection data provided by the present invention when point C in the figure is used as the travel calibration point;

[0056] Figure 4 This is a schematic diagram of the thickness of the fabric during the stemming process provided by the present invention;

[0057] Figure 5 A schematic diagram of a device for detecting sewing thread tension provided by the present invention;

[0058] Figure 6 This is a simplified schematic diagram of the crank-connecting rod mechanism for driving the needle movement provided by the present invention;

[0059] Figure 7 The waveform diagram of the sewing thread tension measured by the present invention;

[0060] Figure 8 This is a simplified diagram of the relationship between the sewing thread tension waveform and the needle movement cycle provided by the invention.

[0061] In the picture:

[0062] 1. Needle; 2. Needle plate; 3. Fabric; 4. Bobbin; 5. Wire guide; 6. Reed; 7. Hall sensor.

[0063] Figure 1-Figure 4 middle:

[0064] L1 is the horizontal line where the upper end point of the needle motion stroke is located;

[0065] L2 is the horizontal line where the travel point of the needle is located during its movement;

[0066] L3 is the horizontal line where the needle plate is located;

[0067] L4 is the horizontal line where the lower end point of the needle movement stroke is located;

[0068] DL1 is the horizontal line of the upper surface of the fabric when the needle is not in contact with the fabric;

[0069] DL2 is the horizontal line of the upper surface of the fabric when the needle pierces the fabric;

[0070] Point A and point C are the two end points of the needle's travel, and point B is any point in the needle's travel.

[0071] Figure 1-Figure 4 In the figure, the actual motion trajectory of the needle is vertical motion. In order to clearly indicate the position of the needle, the needles at three different stroke positions are displayed separately for easy identification.

[0072] Figure 6 In the figure, point D is the rotation point of the driving motor main shaft, point E is the hinge point of the crank and the connecting rod, point F is the hinge point of the connecting rod and the needle, and DF is the motion trajectory of the needle. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0074] The core of the present invention is to provide a method for detecting the thickness of the fabric, which uses indirect measurement and calculation to measure the thickness of the fabric, reduce the influence of different fabric types and different fabric compression conditions on the thickness of the fabric involved in sewing, and facilitate precise adjustment of the sewing machine parameters to ensure the sewing effect.

[0075] The second core of the present invention is to provide a cloth thickness detection system for applying the above-mentioned cloth thickness detection method, which has the same technical features and can solve the same technical problems.

[0076] The third core of the present invention is to provide a thread supply control method including the above-mentioned fabric thickness detection method. By detecting the thickness of the fabric involved in sewing, the single thread supply amount of the thread supply module in the sewing machine is adjusted to improve the final sewing effect.

[0077] The fourth core of the present invention is to provide a sewing machine including the above-mentioned fabric thickness detection system, and / or for applying the above-mentioned fabric thickness detection method and / or thread supply control method, which has the same technical features and can solve the same technical problems.

[0078] Please refer to Figure 1-Figure 3 , a method for detecting the thickness of a cloth 3, for detecting the thickness of a cloth 3 sewn by a needle 1 of a sewing machine;

[0079] The method for detecting the thickness of the fabric 3 comprises the following steps:

[0080] Step S1, obtaining the time interval ΔT between the time point when the needle 1 passes through the stroke calibration point and the time point when the needle 1 pierces the outer surface of the fabric 3;

[0081] Step S2, obtaining the displacement ΔH of the needle 1 within ΔT; obtaining the distance H0 between the stroke calibration point and the needle plate 2;

[0082] Step S3: Calculate the thickness H of the cloth 3 using H0 and ΔH.

[0083] Optionally, the step of obtaining the distance H0 between the stroke calibration point and the needle plate 2 only needs to be performed before step 3, and can be performed in step S1 or S2, or before step S1.

[0084] In the entire movement of needle 1, select any point as the travel calibration point, such as Figure 1-Figure 3 Any point A, B, or C in the figure can be used as a stroke calibration point, where A and C are the two end points of the needle 1 stroke, and point B is any point within the stroke. Since the stroke of the needle 1 in the sewing machine is fixed, the distance H0 between the selected stroke calibration point and the upper surface of the needle plate 2 is fixed. By obtaining the time interval △T between the time point when the needle 1 passes through the stroke calibration point and the time point when it pierces the outer surface of the fabric 3, the displacement △H of the needle 1 within the time interval △T can be calculated according to the kinematic calculation formula. Then, the effective thickness H of the fabric 3 during sewing can be obtained based on H0 and △H.

[0085] Since the range of the time interval △T is the time point when the needle 1 passes through the stroke calibration point and passes through the outer surface of the fabric 3, the outer surface of the fabric 3 is the surface of the fabric 3 away from the needle plate 2, and correspondingly, the inner surface of the fabric 3 is the surface of the fabric 3 close to the needle plate 2; wherein, before the needle 1 passes through the outer surface of the fabric 3, the needle 1 first abuts the outer surface of the fabric 3, that is, the needle 1 reaches the position of DL1, and the feed of the random needle 1 compresses the fabric 3. When the compression resistance of the fabric 3 is greater than the resistance of the fabric 3 to be pierced by the needle 1, the needle 1 pierces the fabric 3. At this time, the position of the needle 1 is at the position of DL2. At this time, the thickness of the fabric 3 is close to the thickness after the sewing thread and the bottom line are tightened after sewing, and can be used as the effective thickness of the fabric 3 participating in sewing, that is, it can be used as the basis for regulating the single thread supply amount, that is, the distance between DL2 and L3, that is, the effective thickness H of the fabric 3 to be measured this time.

[0086] In summary, during the entire detection process, it is only necessary to detect one variable, the time interval △T, and obtain some existing fixed parameters of the sewing machine, so that the effective thickness of the cloth 3 during the sewing process can be obtained by indirect calculation. Compared with the thickness of the cloth 3 directly measured by contact or non-contact methods, the effective thickness of the cloth 3 measured by this method is closer to the thickness of the cloth 3 at the sewing position after sewing, which is more meaningful for the parameter adjustment of the sewing machine drive mechanism and the control of the single thread supply amount.

[0087] In some embodiments, the movement stroke of the needle 1 is recorded by a high-speed camera, and the time points when the needle 1 passes the stroke calibration point and pierces the outer surface of the fabric 3 are captured to obtain the time interval △T.

[0088] In some embodiments, the step of obtaining the time interval ΔT between the time point when the needle 1 passes through the stroke calibration point and the time point when the needle 1 pierces the outer surface of the fabric 3 specifically includes the following steps:

[0089] Step S101, obtaining the tension data of the sewing thread when the needle 1 moves;

[0090] Step S102, obtain the time zone T1 between the time point when the sewing thread tension first changes suddenly in a single movement cycle of the needle 1 and the time point when the needle 1 passes the stroke calibration point, and assign T1 to ΔT.

[0091] During the sewing process, the sewing thread is fed by random needle 1. During the feeding process, the sewing thread is continuously in a tensioned state due to the action of the thread take-up rod. When the sewing thread pierces the fabric 3 with random needle 1, the fabric 3 produces resistance to the feeding of the sewing thread, resulting in a sudden change in the tension of the sewing thread. After detecting the tension of the sewing thread and drawing a waveform diagram, it is found that within a single stroke cycle of the needle 1, the sewing thread will have sudden changes on both sides, that is, there are two significant peaks. The first peak is generated when the needle 1 carries the sewing thread and pierces the fabric 3. At the first sudden change position, the needle 1 pierces the upper surface of the fabric 3, that is, the needle 1 reaches the DL2 position. At the top position of the first peak, the needle 1 completely passes through the fabric 3, that is, the needle 1 reaches the L3 position. The second peak is the tension fluctuation generated after the sewing thread hooks the bottom line in the bobbin 4, that is, the needle 1 reaches the L4 position.

[0092] Therefore, after merging the tension waveform diagram with the needle 1 stroke cycle diagram, the span between the time point when needle 1 passes the stroke calibration point and the time point when the tension first suddenly changes can be obtained, which is the time interval T1. By assigning T1 to △T, the effective thickness H of the fabric 3 can be calculated.

[0093] In some embodiments, the step of obtaining the time interval ΔT between the time point when the needle 1 passes through the stroke calibration point and the time point when the needle 1 pierces the outer surface of the fabric 3 specifically includes the following steps:

[0094] Step S111, taking the end point of the needle 1 on the outer surface of the fabric 3 as the stroke calibration point;

[0095] The steps for calculating the thickness H of the cloth 3 using H0 and △H include:

[0096] Step S211: Calculate and obtain the thickness of the cloth 3: H = H0 - ΔH.

[0097] like Figure 1 As shown, take point A as the stroke calibration point, then the distance between L1 and L3 is H0, which is the inherent value of the sewing machine and can be obtained by consulting the design parameters of the sewing machine. After obtaining △T through the tension waveform diagram and the needle 1 stroke cycle diagram, the needle 1 displacement △H within △T can be calculated according to the formula, which is Figure 1 The distance between L1 and DL2 in the figure. At this time, the effective sewing thickness H of the fabric 3, that is, the distance between DL2 and L3, can be calculated according to the formula H=H0-△H.

[0098] The thickness of the fabric 3 is measured directly or indirectly as the distance between DL1 and L3, and there is a difference of △DL between the two. Therefore, it has a great impact on the parameter control of the sewing machine drive equipment and the control of the single thread supply amount, affecting the final sewing effect.

[0099] The calculation process of H is:

[0100] like Figure 6 As shown in the figure, the following data are obtained through the parameters of the sewing machine:

[0101] , the distance from needle 1 to needle plate 2 at the initial position;

[0102] r, the crank length of the crank-connecting rod mechanism that drives the needle 1 to move, that is, Figure 6 The length of DE shown in , where point D is the position of the rotation axis of the drive motor;

[0103] u, the length of the connecting rod of the crank connecting rod mechanism that drives the needle 1 to move, that is, Figure 6 The length of EF shown in , where point F is the hinge position between the connecting rod and the needle;

[0104] φ0, the initial position driving motor spindle angle;

[0105] φ1, Figure 6 The angle between the crank shown in and the vertical direction;

[0106] φ2, Figure 6 The angle between the connecting rod and the vertical direction shown in ;

[0107] pass Figure 7 and Figure 8 The movement cycle of the needle 1 can be directly output by the control unit of the drive motor, that is, the drive motor drives the main shaft to rotate one circle as one cycle, and then it can be combined with Figure 7 and Figure 8 The data in is used to measure △T;

[0108] When the needle 1 is at the highest point, which is the initial position, and the driving motor rotates at a constant speed, the thickness of the fabric 3 is The following relationship exists:

[0109] ;

[0110] ;

[0111] ;

[0112] ;

[0113] ;

[0114] After deduction, we can conclude that:

[0115] ;

[0116] To simplify the calculation process, we take φ0=0, and we can continue to simplify and get:

[0117] .

[0118] According to the above formula, the thickness of the fabric 3 can be calculated .

[0119] In some embodiments, by adding a displacement sensor in the sewing machine and recording the stroke position of the needle 1 when the sewing thread tension suddenly changes for the first time, the position of DL2 can be obtained, that is, △H can be directly measured by the displacement sensor, and then the distance between DL2 and L3, that is, the effective thickness H of the fabric 3, can be obtained.

[0120] In some embodiments, the step of obtaining the time interval ΔT between the time when the needle 1 passes through the stroke calibration point and the time when the needle 1 pierces the outer surface of the fabric 3 includes:

[0121] The end point of the needle 1 on the inner surface of the fabric 3 is taken as the stroke calibration point;

[0122] The steps for calculating the thickness H of the cloth 3 using H0 and △H include:

[0123] Calculate the thickness of fabric 3: H = △H - H0.

[0124] like Figure 3 As shown, take the lowest stroke point C of needle 1 as the stroke calibration point, then the distance from L4 to L3 is H0, and the distance from DL2 to L4 is △H. When calculating, directly take H=△H-H0.

[0125] The calculation method of ΔH is the same as that in the previous embodiment, and will not be repeated here.

[0126] In some embodiments, such as Figure 2 As shown, any point B in the stroke of needle 1 is selected as the stroke calibration point. When the stroke calibration point is selected, the distance between point B and needle plate 2, that is, the distance between L2 and L3, is measured as H0. The time from needle 1 passing through point B to passing through DL2 is △T, and the distance from L2 to DL2 is △H. When calculating H, take H=H0-△H, where the calculation method of △H is the same as the previous calculation method and will not be repeated.

[0127] In addition to the cloth 3 thickness detection methods disclosed in the above embodiments, the present invention also provides a cloth 3 thickness detection system for applying the above cloth 3 thickness detection methods, comprising:

[0128] A time acquisition module, used to obtain a time interval ΔT between the time point when the needle 1 passes through the stroke calibration point and the time point when the needle 1 pierces the outer surface of the fabric 3;

[0129] A stroke acquisition module is used to calculate and obtain the displacement ΔH of the needle 1 within ΔT, and / or obtain the distance H0 between the stroke calibration point and the needle plate 2;

[0130] The calculation module is used to calculate the thickness H of the cloth 3 through H0 and △H.

[0131] In some embodiments, by adding a high-speed camera and a displacement sensor, the time interval ΔT and the distance H0 can be directly obtained, and the thickness H of the cloth 3 can be directly obtained.

[0132] In addition to the fabric 3 thickness detection method and system disclosed in the above embodiments, the present invention also provides a thread supply control method for controlling the single thread supply amount of the thread supply module in the sewing machine;

[0133] The wire supply quantity control method includes:

[0134] Obtaining the thickness H of the fabric 3 sewn during the current stroke cycle of the needle 1 according to any one of the above-mentioned methods for detecting the thickness of the fabric 3;

[0135] Determine whether the thickness Hn of the cloth 3 in the current stroke cycle is greater than the thickness Hm of the cloth 3 in the previous stroke cycle;

[0136] If yes, control the wire supply module to increase the single wire supply amount;

[0137] If not, determine whether the thickness Hn of the cloth 3 in the current stroke cycle is less than the thickness Hm of the cloth 3 in the previous stroke cycle;

[0138] If yes, control the wire supply module to reduce the single wire supply amount;

[0139] If not, the wire supply module is controlled to maintain the current single wire supply amount.

[0140] like Figure 4 As shown in the figure, when the number of layers of fabric 3 increases or the thickness of fabric 3 changes, the actual thickness involved in sewing increases. For example, in the current stroke cycle of needle 1, the effective thickness of fabric 3 is Hn, while the effective thickness of fabric 3 in the previous stroke cycle is Hm. At this time, if Hn≠Hm, the thickness of fabric 3 has changed. Therefore, the corresponding sewing thread changes with the amount of thread consumed when passing through fabric 3, so as to ensure that the tightening force is constant when the sewing thread is hooked with the bottom thread in bobbin 4, that is, to ensure consistent sewing effect.

[0141] Therefore, this method uses the above-mentioned fabric 3 thickness detection method to detect the effective thickness of the fabric 3 in each stroke cycle of the needle 1, and detects the thickness change of the fabric 3, and then regulates the single thread supply amount of the collinear module, thereby ensuring that the tightening force of the sewing thread and the bottom thread after hooking is consistent, and ensuring consistent sewing effect.

[0142] In some embodiments, if yes, in the step of controlling the wire supply module to increase the single wire supply amount:

[0143] The increase in the single wire supply amount is 2*(Hn-Hm).

[0144] like Figure 4 As shown, in one stroke cycle of the needle 1, the sewing thread passes through the fabric 3 twice. Therefore, when adjusting the thread supply amount, the adjustment amount should be twice the thickness difference of the fabric 3. That is, when the thickness of the fabric 3 increases, the single thread supply amount should increase by twice the length of the thickness difference of the fabric 3.

[0145] Preferably, if yes, in the step of controlling the wire supply module to reduce the single wire supply amount:

[0146] The reduction in the single wire supply amount is 2*(Hm-Hn).

[0147] That is, when the thickness of the cloth 3 decreases, the amount of thread supplied at a single time should be reduced by twice the length of the thickness difference of the cloth 3.

[0148] In addition to the cloth 3 thickness detection method, system and thread supply control method disclosed in the above embodiments, the present invention also provides a sewing machine,

[0149] Used to implement any one of the above-mentioned methods for detecting the thickness of the cloth 3.

[0150] The present invention also provides a sewing machine for implementing any of the above-mentioned thread supply control methods, including a thread supply module. For the structures of other parts of the sewing machine, please refer to the prior art and will not be described in detail herein.

[0151] It is worth noting that there are many ways to obtain the tension of sewing thread, such as Figure 5 As shown, a magnetic wire loop 5 is set in the form of a cantilever beam through a reed 6 in the sewing machine, and a Hall sensor 7 fixed to the sewing machine is set near the wire loop 5. The sewing thread passes through the wire loop 5. When the tension of the sewing thread changes, the wire loop 5 can be driven to jump. When the tension disappears, the wire loop 5 can be reset under the action of the reed 6. The Hall sensor 7 can capture the magnetic field changes when the wire loop 5 jumps, and then obtain the tension change curve of the sewing thread.

[0152] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0153] The above describes in detail the fabric thickness detection method, system, thread supply control method, and sewing machine provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concepts of the present invention. It should be noted that those skilled in the art will be able to make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting the thickness of fabric used for detecting the thickness of fabric sewn by a sewing machine needle, characterized in that: The cloth thickness detection method comprises: Obtain the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric; Get the needle displacement △H within △T and the distance H0 between the stroke calibration point and the needle plate; The fabric thickness H is calculated using H0 and △H.

2. The cloth thickness detection method according to claim 1, characterized in that: The time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained, includes: Get the tension of sewing thread when the needle moves; Obtain the time zone T1 between the time point when the tension of the sewing thread first changes suddenly and the time point when the needle passes the stroke calibration point within a single movement cycle of the needle, and assign T1 to △T.

3. The cloth thickness detection method according to claim 2, characterized in that: The time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained, includes: The end point of the needle stroke on the outer surface of the fabric is taken as the stroke calibration point; The calculation of the fabric thickness H using H0 and ΔH includes: Calculate the fabric thickness H=H0-△H.

4. The cloth thickness detection method according to claim 2, characterized in that: The time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when the needle pierces the outer surface of the fabric is obtained, includes: The end point of the needle stroke on the inner surface of the fabric is taken as the stroke calibration point; The calculation of the fabric thickness H using H0 and ΔH includes: Calculate the fabric thickness H=△H-H0.

5. A cloth thickness detection system, characterized in that: For implementing the cloth thickness detection method according to any one of claims 1 to 4, the cloth thickness detection system comprises: A time acquisition module, used to obtain the time interval ΔT between the time point when the needle passes through the stroke calibration point and the time point when it pierces the outer surface of the fabric; A stroke acquisition module is used to calculate and obtain the needle displacement △H within △T, and / or obtain the distance H0 between the stroke calibration point and the needle plate; The calculation module is used to calculate the thickness H of the fabric through H0 and △H.

6. A thread supply control method for controlling the single thread supply amount of a thread supply module in a sewing machine, characterized in that: The wire supply quantity control method comprises: Obtaining the thickness H of the fabric sewn in the current stroke cycle of the needle according to the fabric thickness detection method according to any one of claims 1 to 4; Determine whether the fabric thickness Hn in the current stroke cycle is greater than the fabric thickness Hm in the previous stroke cycle; If yes, control the wire supply module to increase the single wire supply amount; If not, determine whether the fabric thickness Hn in the current stroke cycle is less than the fabric thickness Hm in the previous stroke cycle; If yes, control the wire supply module to reduce the single wire supply amount; If not, the wire supply module is controlled to maintain the current single wire supply amount.

7. The method for controlling the amount of wire supply according to claim 6, wherein: The control line supply module increases the single line supply amount, including: The increase in the single wire supply amount is 2*(Hn-Hm).

8. The method for controlling the amount of wire supply according to claim 6, wherein: The control line supply module reduces the single line supply amount, including: The reduction in the single wire supply amount is 2*(Hm-Hn).

9. A sewing machine, characterized in that: Used to implement the cloth thickness detection method described in any one of claims 1 to 4.

10. A sewing machine, characterized in that: A method for controlling the amount of wire supply according to any one of claims 6 to 8 is provided, comprising a wire supply module.

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