A control method of an electronic stern-tug device and a sewing machine

Abstract

The application provides a control method of an electronic rear tugger device and a sewing machine. The electronic rear tugger device comprises a rear tugger, a rear tugger shaft, a rotation transmission mechanism, a lifting transmission mechanism and a driving mechanism. The rear tugger is installed on the rear tugger shaft. The rear tugger shaft is rotatably installed on the lifting transmission mechanism. The lifting transmission mechanism is connected with the driving mechanism and is used to drive the rear tugger shaft to lift. The driving mechanism is connected with the rear tugger shaft through the rotation transmission mechanism and is used to drive the rear tugger to rotate. The electronic rear tugger device further comprises a rear tugger electric control unit and a rear tugger operation screen. The rear tugger electric control unit is integrated into a main machine of the sewing machine. The rear tugger electric control unit adjusts the needle pitch of the rear tugger according to the needle pitch of the main machine of the sewing machine. The application adjusts the actual needle pitch of the electronic rear tugger simply, conveniently and quickly, and solves the problem that the rear seam trace is asymmetric and unattractive due to the auxiliary dragging of the rear tugger in the prior art.

Description

Technical Field

[0001] This invention relates to the field of sewing machine equipment technology, and in particular to a control method for an electronic rear roller device and a sewing machine. Background Technology

[0002] The rear towing device plays an auxiliary towing role in the sewing process. It can replace the traditional manual towing, realize automated operation, and effectively solve sewing process problems such as misalignment when sewing thin materials and difficulty in feeding materials when sewing thick materials.

[0003] The operation of the rear roller consists of two parts: lifting and lowering, and feeding. Lifting is used to place the fabric under the rear roller and apply pressure to it. Feeding works in conjunction with the feed dog and presser foot to improve the wrinkling and layering problems of thin fabrics. Currently, rear rollers on the market are divided into electronic and mechanical types. Within one stitch length feeding cycle (the time from when the sewing machine's feed dog is above the needle plate to when it is below), the rear roller rotates at a certain angle; the arc length of this rotation is the actual feed stitch length. To ensure the aesthetic appearance of different fabrics after sewing, the feed stitch length of the rear roller is usually matched to the sewing machine's stitch length. That is, the feed stitch length of the rear roller needs to be adjusted according to the thickness and material of the fabric to match the sewing machine's stitch length. For example, when the fabric needs to be fixed after sewing, without the assistance of the rear roller, such as... Figure 7 As shown, the sewing machine has a fixed stitch length. When a thread-cutting signal is received, the feed dog drive assembly reciprocates twice to cut the thread, thus reinforcing the stitch. When a rear drag wheel is used for auxiliary dragging, as... Figure 8 As shown, the stitch length of the sewing machine is fixed, but due to the auxiliary dragging force of the rear roller, the stitch length of the fabric will be greater than the stitch length of the sewing machine. When the thread-cutting signal is received, the rear roller lifts up or stops rotating, and the sewing machine reciprocates twice to cut the thread and reinforce the stitch. However, when the rear roller is lifted, the stitch length of the fabric backstitch will be less than the stitch length of the fabric when the rear roller is dragging. This will result in messy, asymmetrical, and unsightly stitches after the backstitch is fixed. Therefore, it is necessary to adjust the feed stitch length of the rear roller.

[0004] Currently, some mechanical back rollers on the market control the stitch length by adjusting the lever arm, which is not very precise and not intuitive. Some electronic back rollers, on the other hand, are equipped with electronic control components that read the signal from the sewing machine's main spindle motor and then adjust the stepper motor speed via a control panel to adjust the stitch length of the back roller. However, adjusting the stitch length of the back roller solely by adjusting the stepper motor speed is not intuitive (i.e., the user needs to try adjusting the motor speed multiple times to adjust the stitch length of the back roller to the appropriate parameters). This requires users to manually match the settings, which places higher demands on users and is also more expensive.

[0005] In terms of installation location, the distance between the rear wheel and the pressure foot is relatively far, resulting in poor turning ability and making it unsuitable for scenarios requiring turning.

[0006] For example, our company's patent application, CN 114481462 A, describes a rear drag wheel device for a sewing machine. This device uses a single drive source to achieve the rotation and lifting of the rear drag wheel, simplifying the structure and reducing costs. However, this patent does not address the control of the rear drag wheel's stitch length, nor does it address the problem of messy, asymmetrical, and unsightly stitches caused by the auxiliary dragging of the rear drag wheel. Therefore, further improvements are possible. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a control method for an electronic rear drag wheel device and a sewing machine. By simply, conveniently and quickly adjusting the actual feed stitch distance of the electronic rear drag wheel, the problem of asymmetrical and unsightly stitches caused by the auxiliary dragging of the rear drag wheel in the prior art is solved. At the same time, the distance between the rear drag wheel and the presser foot is reduced, improving the rotatability and making the rear drag wheel suitable for scenarios that require turning.

[0008] To achieve the above and other related objectives, the present invention provides a control method for an electronic rear drag wheel device. The electronic rear drag wheel device includes a rear drag wheel, a rear drag wheel shaft, a rotation transmission mechanism, a lifting transmission mechanism, and a drive mechanism. The rear drag wheel is mounted on the rear drag wheel shaft, and the rear drag wheel shaft is rotatably mounted on the lifting transmission mechanism. The lifting transmission mechanism is connected to the drive mechanism and is used to drive the rear drag wheel shaft to rise and fall. The drive mechanism is connected to the rear drag wheel shaft through the rotation transmission mechanism and is used to drive the rotation of the rear drag wheel. The rear drag wheel presses against the sewing fabric to drag and feed the fabric. Before the sewing is completed, the sewing machine performs a backstitch on the fabric. The drive mechanism lifts the rear drag wheel through the lifting transmission mechanism. The electronic rear drag wheel device sends a feedback signal to the sewing machine to adjust the sewing machine's feed stitch length, so that the sewing machine's feed stitch length is the same as the stitch length of the rear drag wheel dragging and feeding the fabric.

[0009] Preferably, the electronic rear roller device further includes a rear roller electronic control unit and a rear roller operation screen. The rear roller electronic control unit is integrated into the sewing machine host. The sewing machine host is communicatively connected to the rear roller electronic control unit and the drive mechanism. The rear roller electronic control unit adjusts the stitch length of the rear roller according to the feed stitch length of the sewing machine host. The rear roller operation screen is integrated into the sewing machine operation screen and is used to input the stitch length parameters of the rear roller separately.

[0010] Preferably, the control method for the electronic rear trailer wheel device includes the following steps: S1: Lift the presser foot of the sewing machine; place the fabric on the needle plate of the sewing machine; S2: The presser foot of the sewing machine presses down on the fabric; the drive mechanism drives the lifting transmission mechanism to work, and the lifting transmission mechanism drives the rear roller to press down on the fabric. S3: Input the feed stitch length of the sewing machine through the sewing machine operation screen, and the rear roller control unit adjusts the output stitch length of the rear roller according to the feed stitch length of the sewing machine; or input the stitch length parameter of the rear roller separately through the rear roller operation screen, and the rear roller control unit adjusts the output stitch length of the rear roller according to the input stitch length parameter. S4: The drive mechanism drives the rotary transmission mechanism to work, and the rotary transmission mechanism drives the rear roller to rotate, so that the sewing machine sews the fabric.

[0011] Preferably, step S2 is further configured as follows: the sewing machine's feed dog and the machine needle sew the fabric. When the beginning of the fabric moves to below the rear drag wheel, the drive mechanism drives the lifting transmission mechanism to work, and the lifting transmission mechanism drives the rear drag wheel to press on the fabric.

[0012] Preferably, in step S3, when the specifications or process requirements of the sewing fabric do not match the feed stitch length of the sewing machine, the operator adjusts the feed stitch length of the sewing machine, and the rear roller control unit automatically adjusts the output stitch length of the rear roller according to the feed stitch length of the sewing machine.

[0013] Preferably, in step S3, when the specifications or process requirements of the sewing fabric match the feed stitch length of the sewing machine, but the output stitch length of the rear roller does not match the specifications or process requirements of the sewing fabric, the operator inputs the stitch length parameter of the rear roller separately, and the rear roller electronic control unit adjusts the output stitch length of the rear roller according to the input stitch length parameter, so that the feed stitch length of the sewing machine does not change.

[0014] Preferably, the sewing machine is also equipped with a rear roller lifting button, which controls the drive mechanism to lift the rear roller; in step S4, when the sewing machine encounters a cloth blockage or poor feeding during the sewing process, the rear roller lifting button is operated to lift the rear roller to resolve the cloth blockage or poor feeding.

[0015] Preferably, the lifting transmission mechanism includes an eccentric wheel, a connecting rod assembly, and a lifting swing arm. The eccentric wheel is connected to the driving part of the driving mechanism. One end of the lifting swing arm is hinged to the fixed part of the driving mechanism. The rear drag wheel shaft is rotatably mounted on the other end of the lifting swing arm. One end of the connecting rod assembly is hinged to the eccentric wheel, and the other end is hinged to the lifting swing arm.

[0016] Preferably, the connecting rod assembly includes a T-shaped tie rod, a connecting sleeve, a pressure adjusting guide rod, a pressure adjusting nut, a pressure adjusting spring, and a connecting column. The T-shaped tie rod has several oblong grooves, each containing a shaft screw. A shaft screw in one oblong groove is fixed to an eccentric wheel, while the remaining shaft screws in the oblong grooves are fixed to the fixed part of the drive mechanism. The bottom end of the T-shaped tie rod is connected to the top end of the connecting sleeve. The pressure adjusting guide rod passes through the connecting sleeve, and its bottom end is connected to the connecting column. The connecting column is hinged to the lifting swing arm. The pressure adjusting nut is threaded onto the outer periphery of the connecting sleeve. One end of the pressure adjusting spring abuts against the end of the pressure adjusting nut, and the other end abuts against the end of the connecting column. A deep groove ball bearing is also provided on the outer periphery of one end of the eccentric wheel, with a clearance fit between the end of the eccentric wheel and the inner ring of the deep groove ball bearing.

[0017] To achieve the above-mentioned or other purposes, the control method of the above-mentioned electronic rear roller device is adopted; the sewing machine also includes a presser foot and a presser foot rod, the top of the presser foot is fixedly connected to the presser foot rod, and the bottom of the presser foot presses on the fabric or the needle plate of the sewing machine; the middle part of the presser foot has an arc, and the rear roller is arranged in the arc of the middle part of the presser foot.

[0018] As described above, the control method for the electronic rear roller device and the sewing machine of the present invention have the following beneficial effects: 1. Integrated electronic control. The rear wheel electronic control unit is integrated into the sewing machine main unit, and the rear wheel operation screen is integrated into the sewing machine operation screen, reducing costs and making the sewing machine look more aesthetically pleasing and neat.

[0019] 2. The stitch length input parameter of the rear roller is directly set in the sewing machine operation screen. The information is processed by the rear roller electronic control unit, and the input stitch length of the rear roller is directly correlated with the actual output stitch length of the rear roller. This overcomes the problem that in the existing technology, the sewing machine operation screen can only change the actual output stitch length of the rear roller by adjusting the rear roller speed parameter, which requires high user operation and is not intuitive enough for stitch length adjustment.

[0020] 3. The present invention is equipped with a rear roller electronic control unit, which can automatically adjust the input stitch distance of the rear roller according to the input stitch distance of the sewing machine feed, making the operation more convenient for users. However, when the stitch distance parameter of the rear roller is input separately through the rear roller operation screen, the sewing machine feed stitch distance will not change accordingly, thus making it suitable for various sewing processes or user needs, with a wide range of applications.

[0021] 4. The lifting and pressing mode of the rear roller can be set when starting to sew. When the sewing material needs to be pressed down in advance for processes such as adding a zipper, the rear roller is initially in a pressing state. When the sewing material is thick, the rear roller pressing down on the sewing material can easily cause difficulty in feeding the sewing material. In this case, the rear roller is initially in a raised state, and is pressed down again when the sewing material moves under the rear roller.

[0022] 5. Independent lifting and pressing function for the rear roller. A rear roller lifting and pressing button is provided, which is connected to the drive mechanism and is used to lift and press the rear roller. When abnormal situations occur during sewing, such as poor feed, fabric blockage, or significant height differences between some sewing feet, or when lifting the presser foot and roller together may cause fabric shifting, the rear roller lifting and pressing button can be pressed to lift the rear roller independently, facilitating quick handling of the above abnormal situations.

[0023] 6. Post-reinforcement stitch length compensation function. By adding compensation parameters, during the reinforcement operation before sewing is completed, the stitch length of the fabric is made the same as the stitch length when the fabric is being dragged by the rear roller, thus achieving neat and beautiful post-reinforcement stitches. Attached Figure Description

[0024] Figure 1 This is a spatial schematic diagram of the sewing machine of the present invention; Figure 2 This is a front view of the sewing machine of the present invention; Figure 3 for Figure 1 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the installation of the electronic rear wheel device of the present invention with a sewing machine; Figure 5 This is a spatial schematic diagram of the electronic rear tow wheel device of the present invention; Figure 6 This is an exploded view of the electronic rear tugboat device of the present invention; Figure 7 This is a schematic diagram of a sewing machine without a rear roller in the prior art for fixing the seam; Figure 8 A schematic diagram of a sewing machine with a rear-mounted roller for fixing the seam in the prior art; Figure 9 This is a schematic diagram illustrating the gap compensation parameters provided in the control method of the electronic rear tow wheel device of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1. Electronic rear trailer wheel device; 101. Drive motor; 102. First one-way transmission assembly; 103. First synchronous pulley; 104. Washer; 105. Second one-way transmission assembly; 106. Magnet; 107. Eccentric wheel; 108. Piston screw; 109. Motor bracket; 110. Hall sensor; 111. Motor protective cover; 112. Deep groove ball bearing; 113. Pressure adjusting guide rod; 114. T-shaped tie rod; 115. Needle roller bearing; 116. Shaft screw; 117. Connecting sleeve; 118. Pressure adjusting nut; 119. Pressure adjusting spring; 120. Connecting column; 121. Rear trailer wheel; 122. Upper rocker arm; 123. Lower rocker arm; 124. Synchronous belt; 125. Second synchronous pulley; 126. Rear trailer wheel shaft; 2. Presser foot; 3. Sewing machine control panel; 4. Rear roller press button; 5. Adapter plate; 6. Mounting base plate. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0027] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0028] This invention provides an electronic rear roller device for use in sewing machines; for ease of description, as follows: Figure 1 As shown, we define the length direction of the sewing machine as the left-right direction, the width direction as the front-back direction, and the height direction as the up-down direction. Therefore, in Figure 2 In the diagram, the left and right directions of the paper are left and right respectively, the top and bottom directions of the paper are top and bottom respectively, and the front and back of the paper are back and front respectively (the front direction is the direction in which the sewing material moves forward).

[0029] like Figure 2 , Figure 5 , Figure 6As shown, the electronic rear roller device 1 includes a rear roller 121, a rear roller shaft 126, a rotation transmission mechanism, a lifting transmission mechanism, and a drive mechanism. The rear roller 121 is connected to the rear roller shaft 126 via a key. The rear roller shaft 126 is rotatably mounted on the lifting transmission mechanism. The lifting transmission mechanism is connected to the drive mechanism and is used to drive the rear roller shaft 126 to rise and fall. The drive mechanism is connected to the rear roller shaft 126 via the rotation transmission mechanism and is used to drive the rotation of the rear roller 121. The electronic rear roller device 1 also includes a rear roller electronic control unit and a rear roller operation screen. The rear roller electronic control unit is integrated into the sewing machine host and automatically adjusts the stitch length of the rear roller 121 according to the feed stitch length of the sewing machine host. The rear roller operation screen is integrated into the sewing machine operation screen 3 and is used to input the stitch length parameters of the rear roller 121 separately.

[0030] The electronic rear roller device 1 of this invention includes a rear roller electronic control unit and a rear roller operation screen. The rear roller electronic control unit is integrated into the sewing machine host, and the rear roller operation screen is integrated into the sewing machine operation screen 3. This results in a cleaner and more aesthetically pleasing appearance for the sewing machine, while also reducing its cost. The rear roller electronic control unit is communicatively connected to the sewing machine host. It allows for automatic matching of the stitch length of the rear roller 121 with the feed stitch length of the sewing machine host, eliminating the need for multiple manual matching steps by the operator. This is simple, convenient, and fast. Furthermore, the rear roller electronic control unit can compensate for the feed stitch length parameters of the sewing machine host, solving the problem of asymmetrical and unsightly stitches caused by the auxiliary dragging of the rear roller 121 in existing technologies.

[0031] Furthermore, in this embodiment, the rear roller operation screen can input the stitch length parameter of the rear roller 121, thereby directly changing the stitch length of the rear roller 121. This overcomes the shortcomings of the prior art, which requires multiple inputs of the speed parameter of the drive motor 101 through the sewing machine operation screen 3 to change the speed of the drive motor 101 to achieve the stitch length required by the rear roller 121. This also overcomes the shortcomings of the prior art's adjustment method, which is not intuitive and has cumbersome adjustment assistance.

[0032] In this embodiment, the formula for the actual output stitch pitch of the rear drag wheel 121 is as follows: ① Output stitch pitch of rear trailer 121 = (Input stitch pitch of rear trailer 121 + Stitch pitch compensation) * Speed ​​compensation parameter; ② The output stitch pitch of the rear roller 121 = the speed of the drive motor 101 * (the gear ratio of the first synchronous pulley 103 / the second synchronous pulley 125) * the diameter of the rear roller 121 * (the feeding end angle of the rear roller 121 - the feeding start angle of the rear roller 121) / (the speed of the sewing machine spindle * 360°).

[0033] Wherein: the input stitch length of the rear roller 121 in formula ① is directly input through the sewing machine operation screen 3; the stitch length compensation is a constant (default is zero; in some sewing scenarios, users want the stitch length of the rear roller 121 to be greater than the feed stitch length of the sewing machine, and the value is the input constant); the speed compensation parameter is a constant. During the feeding process of the sewing machine, the actual feed stitch length of the rear roller 121 will change due to some external factors at high speed and low speed (such as changes in friction force and changes in stepper motor torque). This coefficient is different at high speed and low speed of the sewing machine, but it is a constant.

[0034] In formula ②, the output stitch length of the rear roller 121 is derived from formula ①; the gear ratio of the first synchronous wheel 103 / second synchronous wheel 125 is a constant and can be set by parameters. When changing to a different rotating transmission mechanism, the parameters can be adjusted according to the actual gear ratio to achieve rapid switching without affecting the correspondence between the stitch length value of the rear roller 121 and the actual feeding stitch length of the rear roller 121; the feeding end angle of the rear roller 121 is the mechanical angle of the main shaft motor when the sewing machine feed tooth finishes feeding and is about to enter the needle plate plane, which can be obtained from the sewing machine operation screen 3; the feeding start angle of the rear roller 121 is the mechanical angle of the main shaft motor when the sewing machine feed tooth starts feeding and is about to exceed the needle plate plane, which can be obtained from the sewing machine operation screen 3; the sewing machine main shaft speed is the real-time speed of the main shaft during sewing; Thus, the rotational speed of the drive motor 101 in Formula ② can be calculated using Formula ②, allowing the rear roller control unit to directly adjust the rotational speed of the drive motor 101, thereby controlling the actual stitch length of the rear roller 121. In this application, when the input stitch length parameter of the rear roller 121 is input through the sewing machine operation screen 3, the rotational speed of the drive motor 101 is calculated using the aforementioned Formulas ① and ②. Then, the rear roller control unit adjusts the rotational speed of the drive motor 101 to control the actual stitch length of the rear roller 121. This solves the problem in the prior art where operators repeatedly need to directly adjust the rotational speed of the drive motor 101 multiple times to achieve the desired output stitch length of the rear roller 121, resulting in cumbersome operation and high technical requirements for users.

[0035] Preferred, such as Figure 6As shown, the drive mechanism includes a drive motor 101, a motor bracket 109, a first one-way transmission assembly 102, and a second one-way transmission assembly 105. The motor shaft of the drive motor 101 passes through the motor bracket 109. The first one-way transmission assembly 102 and the second one-way transmission assembly 105 are both mounted on the motor shaft. The first one-way transmission assembly 102 and the second one-way transmission assembly both include an inner rotating part and an outer transmission part that can only rotate unidirectionally relative to the inner rotating part. The inner rotating parts of the first one-way transmission assembly 102 and the second one-way transmission assembly 105 are fixedly connected to the motor shaft by a flat key. The flat key is used to limit the radial relative displacement between the inner rotating parts of the first one-way transmission assembly 102 and the second one-way transmission assembly 105 and the motor shaft. The rotation directions of the first one-way transmission assembly 102 and the second one-way transmission assembly 105 are opposite to each other. Furthermore, in this embodiment, the motor bracket 109 is U-shaped, and a shim 104 is provided between the first one-way transmission assembly 102 and the second one-way transmission assembly 105. The shim 104 is used to limit the axial relative displacement of the first one-way transmission assembly 102 and the second one-way transmission assembly 105 on the motor shaft. A motor protective cover 111 is also provided on the outer periphery of the drive motor 101 in this application to protect the drive mechanism.

[0036] Furthermore, the drive mechanism in this application is consistent with the drive mechanism disclosed in publication number CN114481462A, as detailed in paragraphs

[0069] -

[0070] of that patent. In this embodiment, when the drive motor 101 rotates forward, the first one-way transmission component 102 rotates, and the rear wheel 121 rotates; when the drive motor 101 rotates in reverse, the second one-way transmission component 105 rotates, and the rear wheel 121 is lifted and pressed.

[0037] Preferred, such as Figure 6 As shown, the rotary transmission mechanism includes a first synchronous pulley 103, a second synchronous pulley 125, and a synchronous belt 124 that drivesly connects the first synchronous pulley 103 and the second synchronous pulley 125. The first synchronous pulley 103 is coaxially fixedly connected to the outer transmission part of the first one-way transmission assembly 102 by fastening screws, and the second synchronous pulley 125 is coaxially fixedly connected to the rear trailer axle 126 by a flat key. Furthermore, the rotary transmission mechanism in this application is consistent with the rotary transmission mechanism disclosed in publication number CN114481462A, as detailed in paragraph

[0078] of that patent.

[0038] Preferred, such as Figure 6As shown, the lifting transmission mechanism includes an eccentric wheel 107, a connecting rod assembly, and a lifting swing arm. The eccentric wheel 107 is coaxially and fixedly connected to the outer transmission part of the second one-way transmission assembly 105 via a flat key. The top end of the lifting swing arm is hinged to the motor bracket 109, and the rear drag wheel shaft 126 is rotatably mounted on the bottom end of the lifting swing arm. The top end of the connecting rod assembly is hinged to the eccentric wheel 107, and the bottom end is hinged to the lifting swing arm. In this embodiment, the lifting swing arm includes an upper rocker arm 122 and a lower rocker arm 123, which are hinged together by a pin. Furthermore, the lifting swing arm in this application is consistent with the lifting swing arm disclosed in publication number CN114481462A, and the connection method between the lifting swing arm and the rear drag wheel shaft 126 in this application is consistent with the connection method disclosed in publication number CN114481462A, as detailed in paragraphs

[0076] -

[0077] of that patent.

[0039] Preferred, such as Figure 6 As shown, the connecting rod assembly includes a T-shaped tie rod 114, a connecting sleeve 117, a pressure adjusting guide rod 113, a pressure adjusting nut 118, a pressure adjusting spring 119, and a connecting post 120. The T-shaped tie rod 114 has several oblong grooves, each containing a shaft screw 116. One shaft screw 116 in any one oblong groove is fixed to the eccentric wheel 107, while the remaining shaft screws 116 in the other oblong grooves are securely fixed to the motor bracket 109. The T-shaped tie rod 114... The bottom end of 4 is fixedly connected to the top end of the connecting sleeve 117. The pressure adjusting guide rod 113 passes through the connecting sleeve 117 vertically, and the bottom end of the pressure adjusting guide rod 113 is connected to the connecting post 120. The connecting post 120 is hinged to the bottom end of the lifting swing rod. The pressure adjusting nut 118 is threadedly connected to the outer periphery of the connecting sleeve 117. The top end of the pressure adjusting spring 119 abuts against the bottom end face of the pressure adjusting nut 118, and the bottom end of the pressure adjusting spring 119 abuts against the top end face of the connecting post 120. In this embodiment, the specification of the pressure adjusting nut 118 is M14.

[0040] Furthermore, in this embodiment, there are three waist-shaped grooves, distributed at the upper, lower, and front parts of the T-shaped tie rod 114. The upper and lower waist-shaped grooves extend vertically, while the front waist-shaped groove extends horizontally. There are three shaft screws 116, each fitted with a needle roller bearing 115. The shaft screw 116 in the front waist-shaped groove is fastened to the eccentric wheel 107, while the shaft screws 116 in the upper and lower waist-shaped grooves are fastened to the upper and lower parts of the motor bracket 109, respectively. When the drive motor 101 drives the eccentric wheel 107 to rotate, the shaft screw 116 on the eccentric wheel 107 will rotate with the eccentric wheel 107, thereby driving the T-shaped tie rod 114 to move up and down through the front waist groove. The upper waist groove and the lower waist groove move along the shaft screw 116 set in the upper waist groove and the lower waist groove, thereby driving the connecting sleeve 117 to move up and down.

[0041] Furthermore, such as Figure 6 As shown, in this embodiment, the connecting sleeve 117 is a cylinder that is wider at the top and narrower at the bottom. Threads are formed on the outer circumference of the connecting sleeve 117, and the pressure adjusting nut 118 is fastened to the outer circumference of the connecting sleeve 117 via internal threads and threads. By changing the position of the pressure adjusting nut 118 on the outer circumference of the connecting sleeve 117, the stroke of the pressure adjusting spring 119 is compressed, thereby changing the pressure of the rear drag wheel 121 on the sewing material. Furthermore, the connecting sleeve 117, pressure adjusting guide rod 113, pressure adjusting nut 118, pressure adjusting spring 119, and connecting post 120 in this embodiment are all consistent with the structure disclosed in publication number CN114481462A, as detailed in paragraph

[0077] of that patent.

[0042] Preferred, such as Figure 6 As shown, the eccentric wheel 107 has a smaller outer diameter at its left end and a larger outer diameter at its right end. A deep groove ball bearing 112 is also installed in the motor bracket 109. The outer circumference of the left end of the eccentric wheel 107 is clearance-fitted with the inner ring of the deep groove ball bearing 112, while the outer ring of the deep groove ball bearing 112 is securely fitted within the motor bracket 109. The purpose of installing the deep groove ball bearing 112 is to restrict the rotation trajectory of the eccentric wheel 107 when the drive motor 101 drives it to rotate, thus preventing the eccentric wheel 107 from shifting axially along the motor shaft after long-term operation.

[0043] Furthermore, a magnet 106 is provided on the outer circumferential surface of the right end of the eccentric wheel 107, and a Hall sensor 110 is provided on the motor bracket 109. The Hall sensor 110 is used to sense the position of the magnet 106. Further, a recess is provided on the outer circumferential surface of the right end of the eccentric wheel 107, and a through hole is provided on the motor bracket 109, into which a plunger screw 108 is inserted. When the drive motor 101 drives the eccentric wheel 107 to rotate, the eccentric wheel 107 drives the T-shaped tie rod 114 to move up and down, thereby lifting and pressing the rear trailer wheel 121. The purpose of providing the recess and the plunger screw 108 is to prevent the rear trailer wheel 121 from shifting in the vertical direction when it is lifted or pressed down. By engaging the plunger screw 108 in the recess, the vertical movement of the rear trailer wheel 121 is restricted. In this embodiment, the magnet 106, Hall sensor 110, recess, and plunger screw 108 are all consistent with the structure disclosed in publication number CN114481462A, as detailed in paragraphs

[0079] -

[0080] of that patent.

[0044] To achieve the above or other objectives, the present invention also discloses a control method for an electronic rear tug wheel device, employing the aforementioned electronic rear tug wheel device 1, comprising the following steps: A1: The operator starts the drive motor 101 by operating the sewing machine operation screen 3. The sewing machine host receives the control signal and controls the drive motor 101 to work. The drive motor 101 reverses. At this time, the second one-way transmission component 105 drives the eccentric wheel 107 to rotate. The eccentric wheel 107 drives the T-shaped pull rod 114 to move upward, lifting the rear drag wheel 121. That is, there is a gap between the rear drag wheel 121 and the needle plate. A2: The operator places the fabric on the needle plate of the sewing machine and controls the drive motor 101 to work. The drive motor 101 reverses, and at this time the second one-way transmission component 105 drives the eccentric wheel 107 to rotate. The eccentric wheel 107 drives the T-shaped pull rod 114 to move downward, thereby pressing down the rear drag wheel 121 and pressing the rear drag wheel 121 onto the fabric. A3: The operator selects the appropriate feed stitch length parameters for the sewing machine based on the material and thickness of the fabric, and inputs them into the sewing machine main unit via the sewing machine operation screen 3. The sewing machine main unit processes the parameter information and feeds it back to the rear roller control unit. The rear roller control unit automatically adjusts the stitch length of the rear roller 121 according to the feed stitch length of the sewing machine main unit, so that the feed stitch length of the sewing machine main unit matches the stitch length of the rear roller 121; or, the stitch length parameters of the rear roller 121 can be input separately via the rear roller operation screen in the sewing machine operation screen 3, without changing the feed stitch length of the sewing machine, and the rear roller control unit adjusts the stitch length of the rear roller 121 according to the input stitch length parameters. A4: The operator controls the drive motor 101 through the sewing machine operation screen 3. When the drive motor 101 rotates forward, the first one-way transmission component 102 drives the first synchronous pulley 103 to rotate, which in turn drives the rear drag wheel 121 to rotate through the synchronous belt 124 and the second synchronous pulley 125. The rear drag wheel 121 assists in dragging the sewing material and works with the sewing machine's feed dog and needle to sew the material. After sewing is completed, the sewing machine host drives the sewing machine's thread cutting mechanism to cut the thread. Then the drive motor 101 reverses, the rear drag wheel 121 stops rotating, and moves upward through the T-shaped pull rod 114. The rear drag wheel 121 separates from the sewing material, and the operator removes the sewing material from the needle plate.

[0045] Preferably, in step A4, before the sewing machine cuts the thread, it also performs a seam-fixing operation on the fabric, such as... Figures 7-9 As shown, the sewing fixation operation in this embodiment requires three stitches. The first stitch is a normal stitch. When the sewing machine host receives the thread-cutting signal, the drive motor 101 reverses to lift the rear roller 121. Then, the sewing machine host controls the feed dog and needle to backstitch the fabric for the second stitch. After the second stitch is finished, the sewing machine host controls the feed dog and needle to backstitch the fabric for the third stitch. After the third stitch is finished, the sewing machine's thread-cutting mechanism cuts the thread, and the operator can remove the fabric from the sewing machine's needle plate.

[0046] like Figure 8 As shown, during the seam fixing operation, since the first seam fixing is a normal sewing process assisted by the rear drag wheel 121 (there is friction between the rear drag wheel 121 and the fabric), while the second and third seam fixings are performed after the rear drag wheel 121 is lifted, the stitch length of the first seam fixing will be greater than that of the second and third seam fixings. Therefore, as... Figure 9 As shown, in this embodiment, when the first fixed seam is finished sewing and the drive motor 101 lifts the rear roller 121, the rear roller control unit sends a signal to the sewing machine host and transmits a fixed seam compensation parameter. This fixed seam compensation parameter will be superimposed on the feed stitch distance of the sewing machine, so that the stitch distance of the second and third fixed seams becomes larger, thus being the same as the stitch distance of the first fixed seam, ensuring the aesthetics after the fixed seam operation is completed.

[0047] Furthermore, since the stitch length of the first fixed seam is affected by the friction between the rear roller 121 and the fabric, the fixed seam compensation parameter is determined based on the magnitude of the friction between the fabric and the rear roller 121 and is a constant.

[0048] Preferably, before the sewing operation begins in step A2, the rear drag wheel 121 is pressed onto the fabric, meaning its initial state is a pressed-down state. This state is suitable for scenarios where the fabric needs to be pressed down beforehand, such as when installing a zipper. In other embodiments, before the sewing operation begins, the rear drag wheel 121 is in a raised state, meaning its initial state is a raised-down state. This state is suitable for scenarios where the fabric start point is relatively thick (in this embodiment, a start point thickness greater than 5mm is considered a relatively thick start point). If the rear drag wheel 121 is initially pressed onto the fabric, it will cause feeding difficulties and may easily cause fabric blockage. When the fabric start point reaches below the rear drag wheel 121 after N stitches, the rear drag wheel 121 then presses down to assist in dragging, which can effectively solve the problem of feeding difficulties when the fabric start point is relatively thick.

[0049] Preferably, in step A3, when the operator inputs the feed stitch length of the sewing machine, the rear roller control unit changes the stitch length of the rear roller 121 by changing the speed of the drive motor 101. Under normal conditions, the feed stitch length of the sewing machine is the same as the stitch length of the rear roller 121.

[0050] When the operator inputs the stitch length of the rear roller 121, the rear roller control unit changes the speed of the drive motor 101, thereby changing the stitch length of the rear roller 121. However, the feed stitch length of the sewing machine will not change accordingly. This is suitable for certain special sewing process requirements or user needs, as well as situations where the initial stitch length of the rear roller 121 is not suitable for the sewing process and the stitch length of the rear roller 121 needs to be adjusted separately to adapt to the feed stitch length of the sewing machine.

[0051] To achieve the above or other objectives, the present invention also discloses a sewing machine including the aforementioned electronic rear roller device 1; as shown Figure 4 As shown, the electronic rear wheel device 1 is fixed to the rear window panel of the sewing machine via the mounting base plate 6 and the adapter plate 5. Figure 1 , Figure 3 As shown, the sewing machine also includes a presser foot 2 and a presser foot bar. The top of the presser foot 2 is fixedly connected to the presser foot bar, and the bottom of the presser foot 2 presses on the fabric or the needle plate of the sewing machine. The middle part of the presser foot 2 has a rearward arc, and the rear roller 121 is set in the arc of the middle part of the presser foot 2, thereby shortening the distance between the rear roller 121 and the presser foot 2 and improving the rotation of the sewing machine.

[0052] Preferred, such as Figure 2 As shown, the sewing machine is also equipped with a rear roller lifting button 4, which is connected to the drive mechanism and used to lift and press the rear roller 121. The operator no longer needs to operate through the sewing machine control panel 3; it is a one-button operation that is convenient and quick. In this embodiment, the separate rear roller lifting button 4 is suitable for situations such as poor material feeding or fabric blockage during sewing, or when there is a large height difference in the fabric ends. This solves the problems of manually lifting the roller or repeatedly clicking the sewing machine control panel 3 in the prior art, which is laborious and unsafe, or where lifting the presser foot 2 and the rear roller 121 together can easily cause fabric displacement.

[0053] The electronic rear roller device 1, control method, and sewing machine involved in this invention have the following beneficial effects: 1. Integrated electronic control. The rear wheel electronic control unit is integrated into the sewing machine main unit, and the rear wheel operation screen is integrated into the sewing machine operation screen 3, which reduces costs and makes the sewing machine look beautiful and neat.

[0054] 2. Set the stitch length input parameter option for the rear roller 121 in the sewing machine operation screen 3. Based on the calculation formula in the rear roller control unit, directly adjust the speed of the drive motor 101. There is no need for the operator to gradually adjust the speed of the drive motor 101 multiple times, which reduces the operation requirements for the user and makes the stitch length adjustment of the rear roller 121 more convenient and faster.

[0055] 3. The present invention is equipped with a rear roller electronic control unit, which can automatically adjust the output stitch distance of the rear roller 121 according to the input sewing machine feed stitch distance, making the user operation more convenient. However, when the stitch distance parameter of the rear roller 121 is input separately through the rear roller operation screen, the sewing machine feed stitch distance will not change accordingly, thus making it suitable for various sewing processes or user needs, with a wide range of applications.

[0056] 4. The lifting and pressing mode of the rear roller 121 during the start of sewing can be set. When the sewing material needs to be pressed down in advance for processes such as adding a zipper, the rear roller 121 is initially in a pressed-down state. When the sewing material is thick, that is, when the rear roller 121 is pressed down on the sewing material, it is easy to cause difficulty in feeding the sewing material. At this time, the rear roller 121 is initially in a raised state, and is pressed down again when the sewing material moves under the rear roller 121. This expands the application range of the sewing machine and improves its applicability.

[0057] 5. One-button lifting and pressing function for rear roller 121. A rear roller lifting and pressing button 4 is provided, which is connected to the drive mechanism and is used to lift and press the rear roller 121. When abnormal situations such as poor material feeding or fabric blockage occur during sewing, or when there is a large difference in the height of some sewing feet, or when lifting the presser foot 2 and the rear roller 121 together may cause fabric displacement, the rear roller lifting and pressing button 4 can be pressed to lift the rear roller 121 separately, which facilitates quick handling of the above abnormal situations.

[0058] 6. Post-reinforcement stitch length compensation function. By adding a reinforcement compensation parameter, during the reinforcement operation before thread cutting, the stitch length of the sewing material is made the same as the stitch length when the rear drag wheel 121 is dragging, thereby achieving neat and beautiful post-reinforcement stitches.

[0059] 7. The sewing machine presser foot 2 in this application has a certain curvature, and the rear roller 121 is set in the curvature of the presser foot 2, which reduces the distance between the rear roller 121 and the presser foot 2, resulting in higher rotation performance.

[0060] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A control method for an electronic rear trailer wheel device, the electronic rear trailer wheel device (1) comprising a rear trailer wheel (121), a rear trailer wheel shaft (126), a rotation transmission mechanism, a lifting transmission mechanism, and a drive mechanism, wherein the rear trailer wheel (121) is mounted on the rear trailer wheel shaft (126), the rear trailer wheel shaft (126) is rotatably mounted on the lifting transmission mechanism, the lifting transmission mechanism is connected to the drive mechanism, and is used to drive the rear trailer wheel shaft (126) to lift; the drive mechanism is connected to the rear trailer wheel shaft (126) through the rotation transmission mechanism, and is used to drive the rotation of the rear trailer wheel (121); characterized in that: The rear drag wheel (121) presses on the sewing material to drag and feed the material. Before the sewing is completed, the sewing machine performs a back-fixing of the sewing material. The drive mechanism lifts the rear drag wheel (121) through the lifting transmission mechanism. The electronic rear drag wheel device (1) sends a feedback signal to the sewing machine to adjust the feeding stitch distance of the sewing machine so that the feeding stitch distance of the sewing machine is the same as the stitch distance of the rear drag wheel (121) dragging and feeding the material.

2. The control method for the electronic rear tugboat device according to claim 1, characterized in that: The electronic rear roller device (1) also includes a rear roller electronic control unit and a rear roller operation screen. The rear roller electronic control unit is integrated into the sewing machine host. The sewing machine host is communicatively connected to the rear roller electronic control unit and the drive mechanism. The rear roller electronic control unit adjusts the stitch length of the rear roller (121) according to the feeding stitch length of the sewing machine host. The rear roller operation screen is integrated into the sewing machine operation screen (3). The rear roller operation screen is used to input the stitch length parameters of the rear roller (121) separately and control the rear roller (121) to achieve preset functions.

3. The control method for the electronic rear tugboat device according to claim 2, characterized in that: The steps are as follows: S1: Lift the presser foot (2) of the sewing machine; place the fabric on the needle plate of the sewing machine; S2: The presser foot (2) of the sewing machine presses down on the fabric; the drive mechanism drives the lifting transmission mechanism to work, and the lifting transmission mechanism drives the rear drag wheel (121) to press down on the fabric; S3: Input the feed stitch length of the sewing machine through the sewing machine operation screen (3), and the rear roller control unit adjusts the output stitch length of the rear roller (121) according to the feed stitch length of the sewing machine; or input the stitch length parameter of the rear roller (121) separately through the rear roller operation screen, and the rear roller control unit adjusts the output stitch length of the rear roller (121) according to the input stitch length parameter; S4: The drive mechanism drives the rotary transmission mechanism to work, and the rotary transmission mechanism drives the rear drag wheel (121) to rotate, and the sewing machine sews the fabric.

4. The control method for the electronic rear tugboat device according to claim 3, characterized in that: Step S2 is also set as follows: the sewing machine's feed dog and the needle sew the fabric. After the sewing machine has sewed N stitches, the drive mechanism drives the lifting transmission mechanism to work. The lifting transmission mechanism drives the rear drag wheel (121) to press on the fabric.

5. The control method for the electronic rear tugboat device according to claim 3, characterized in that: In step S3, when the specifications or process requirements of the sewing material do not match the feed stitch length of the sewing machine, the operator adjusts the feed stitch length of the sewing machine, and the rear roller control unit automatically adjusts the output stitch length of the rear roller (121) according to the feed stitch length of the sewing machine.

6. The control method for the electronic rear tugboat device according to claim 3, characterized in that: In step S3, when the specifications or process requirements of the sewing fabric match the feed stitch length of the sewing machine, but the output stitch length of the rear roller (121) does not match the specifications or process requirements of the sewing fabric, the operator inputs the stitch length parameter of the rear roller (121) separately. The rear roller control unit adjusts the output stitch length of the rear roller (121) according to the input stitch length parameter, and the feed stitch length of the sewing machine does not change.

7. The control method for the electronic rear tugboat device according to claim 3, characterized in that: The sewing machine is also equipped with a rear roller lifting button (4), which controls the drive mechanism to lift the rear roller (121). In step S4, when the sewing machine encounters a blockage or poor feeding during the sewing process, the rear roller lifting button (4) is operated to lift the rear roller (121) to deal with the blockage or poor feeding.

8. The control method for the electronic rear tugboat device according to claim 1, characterized in that: The lifting transmission mechanism includes an eccentric wheel (107), a connecting rod assembly, and a lifting swing arm. The eccentric wheel (107) is connected to the driving part of the driving mechanism. One end of the lifting swing arm is hinged to the fixed part of the driving mechanism. The rear drag wheel shaft (126) is rotatably mounted on the other end of the lifting swing arm. One end of the connecting rod assembly is hinged to the eccentric wheel (107), and the other end is hinged to the lifting swing arm.

9. The control method for the electronic rear tugboat device according to claim 8, characterized in that: The connecting rod assembly includes a T-shaped tie rod (114), a connecting sleeve (117), a pressure adjusting guide rod (113), a pressure adjusting nut (118), a pressure adjusting spring (119), and a connecting column (120). The T-shaped tie rod (114) has several oblong grooves, each containing a shaft screw (116). One shaft screw (116) in any one oblong groove is fixed to an eccentric wheel (107), while the remaining shaft screws (116) in the other oblong grooves are fixed to the fixed part of the drive mechanism. The bottom end of the T-shaped tie rod (114) is connected to the top end of the connecting sleeve (117). The pressure adjusting... The guide rod (113) passes through the connecting sleeve (117), and the bottom end of the pressure adjusting guide rod (113) is connected to the connecting column (120), which is hinged to the lifting swing rod; the pressure adjusting nut (118) is threadedly connected to the outer periphery of the connecting sleeve (117); one end of the pressure adjusting spring (119) abuts against the end of the pressure adjusting nut (118), and the other end abuts against the end of the connecting column (120); a deep groove ball bearing (112) is also provided on the outer periphery of one end of the eccentric wheel, and the inner ring of the eccentric wheel (107) is clearance-fitted with the inner ring of the deep groove ball bearing (112).

10. A sewing machine, characterized in that: The control method of the electronic rear roller device according to any one of claims 1-9 is adopted; the sewing machine further includes a presser foot (2) and a presser foot rod, the top of the presser foot (2) is fixedly connected to the presser foot rod, and the bottom of the presser foot (2) presses on the sewing material or the needle plate of the sewing machine; the middle part of the presser foot (2) has an arc, and the rear roller (121) is arranged in the arc of the middle part of the presser foot (2).

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