Expansion mechanism, lower swinging machine and control method of expansion mechanism

Abstract

The invention discloses an expansion mechanism, a lower hem machine and a control method of the expansion mechanism, and relates to the technical field of lower hem machines, the expansion mechanism comprises a machine head, an auxiliary wheel and an expansion wheel, the auxiliary wheel and the expansion wheel are rotatably arranged on the machine head, and the auxiliary wheel and the expansion wheel are matched to sleeve to-be-sewn cloth; the auxiliary wheel can be driven to rotate forwards by taking a self rotating axis as a circle center; the expansion wheel can be driven to move away from the auxiliary wheel in the first direction so as to tension the to-be-sewn cloth, and the expansion wheel can be driven to rotate in the forward direction with the rotation axis of the expansion wheel as the circle center so as to further tension the to-be-sewn cloth of the lower layer segment. The tension of the to-be-sewn cloth of the lower-layer section and the tension of the to-be-sewn cloth of the upper-layer section sequentially reach preset values and are kept consistent. The expansion mechanism solves the technical problems that when an existing automatic hem sewing machine sews cloth, the situations of cloth wrinkling, uneven stitches and the like possibly occur, and the cloth sewing effect is affected.

Description

Technical Field

[0001] This invention relates to the field of swing mechanism technology, and particularly to an expansion mechanism, a swing mechanism, and a control method for the expansion mechanism. Background Technology

[0002] Existing automatic hem-dropping machines include a head sewing unit, an auxiliary feeding unit, a correction unit, and an expansion unit. The main workflow involves placing the fabric in the designated position, then the expansion wheel in the expansion unit expands to the left to tension the fabric before sewing. The expansion wheel is driven by a synchronous belt, and its surface is equipped with friction wheels to increase friction with the fabric.

[0003] However, in existing automatic hem-lifting machines, the expanding rollers are stationary during expansion. At this time, under the action of the friction rollers, the fabric is often in a state of tension at the top and looseness at the bottom. Furthermore, different fabrics have varying degrees of smoothness, resulting in inconsistent fabric tension during the expansion process and varying tension effects. If sewing begins at this point, wrinkles and uneven stitches may occur, affecting the sewing quality. Therefore, this paper proposes an expanding mechanism, a hem-lifting machine, and a control method for the expanding mechanism to address these problems. Summary of the Invention

[0004] The purpose of this invention is to provide an expansion mechanism, a hem machine, and a control method for the expansion mechanism, which solves the technical problems that existing automatic hem machines may cause fabric wrinkling and uneven stitches when sewing fabric, thus affecting the sewing effect.

[0005] To achieve the above objectives, the present invention provides an expansion mechanism, comprising: a sewing head and an auxiliary wheel and an expansion wheel rotatably disposed on the sewing head, wherein the auxiliary wheel and the expansion wheel cooperate to fit the fabric to be sewn.

[0006] The auxiliary wheel can be driven to rotate in the positive direction around its own axis of rotation, so as to drive the fabric to be sewn to rotate in the positive direction;

[0007] The expansion wheel can be driven to move away from the auxiliary wheel in a first direction to tension the fabric to be sewn, and the expansion wheel can be driven to rotate positively around its own axis of rotation to further tension the lower segment of the fabric to be sewn, so that the tension of the lower segment of the fabric to be sewn and the upper segment of the fabric to be sewn reach a preset value in sequence and remain consistent.

[0008] Preferably, a tension detection device is also provided, the tension detection device comprising: a mounting base disposed on the machine head, a first sensing probe and an upper lever disposed on the mounting base, a first end of the upper lever being rotatably connected to the mounting base, and a second end of the upper lever abutting against the inner surface of the upper segment of fabric to be sewn, the first sensing probe being used to monitor the height position of the upper lever.

[0009] Preferably, a first adjusting plate is slidably disposed on the mounting base, and the upper lever is connected to the first adjusting plate through a first elastic element. The first adjusting plate can be driven to reciprocate along a first direction to adjust the extension and retraction stroke of the first elastic element.

[0010] Preferably, the tension detection device further includes: a second sensing probe and a lower lever disposed on the mounting base, the first end of the lower lever being rotatably connected to the mounting base, the second end of the lower lever abutting the inner surface of the lower layer segment of fabric to be sewn, and the second sensing probe being used to monitor the height position of the lower lever.

[0011] Preferably, a second adjusting plate is slidably disposed on the mounting base, and the lower lever is connected to the second adjusting plate through a second elastic element. The second adjusting plate can be driven to reciprocate along a first direction to adjust the extension and retraction stroke of the second elastic element.

[0012] Preferably, when the length direction of the upper lever is perpendicular to the first direction, the end of the second end of the upper lever is located at the upper limit position; when the length direction of the lower lever is perpendicular to the first direction, the end of the second end of the lower lever is located at the lower limit position.

[0013] A hem-lifting machine includes a sewing mechanism and an expansion mechanism as described in any of the preceding claims.

[0014] Accordingly, the present invention also provides an expansion mechanism method, applied to any of the expansion mechanisms described above, wherein the control method includes:

[0015] The fabric to be sewn is placed on the auxiliary wheel and the expansion wheel;

[0016] The expansion wheel is controlled to move away from the auxiliary wheel along the first direction at a preset speed, and the expansion wheel is controlled to rotate in the positive direction with its own rotation axis as the center at a first preset angular velocity until the tension of the upper segment of the fabric to be sewn reaches a preset value.

[0017] Continue to control the expansion wheel to move away from the auxiliary wheel along the first direction at a preset speed, and adjust the angular velocity of the expansion wheel in real time to keep the tension of the upper layer of fabric to be sewn constant, and make the tension of the lower layer of fabric to be sewn reach a preset value and keep it consistent with the tension of the upper layer of fabric to be sewn.

[0018] Preferably, the step of controlling the expansion wheel to move away from the auxiliary wheel along the first direction at a preset speed, and controlling the expansion wheel to rotate in the positive direction around its own axis of rotation at a first preset angular velocity, includes:

[0019] Substituting the speed of the expanding wheel as it moves away from the auxiliary wheel along the first direction and the radius of the expanding wheel into the angular velocity calculation formula, we obtain the angular velocity of the expanding wheel when it rotates positively around its own axis of rotation. The angular velocity calculation formula is as follows:

[0020] ;

[0021] in,

[0022] W represents the angular velocity of the expansion wheel when it rotates positively about its own axis of rotation.

[0023] V represents the speed at which the expansion wheel moves away from the auxiliary wheel along the first direction;

[0024] R represents the radius of the expansion wheel.

[0025] Preferably, before the step of until the tension of the upper segment of fabric to be sewn reaches a preset value, the method further includes: controlling the auxiliary wheel to rotate in the positive direction with its own rotation axis as the center at a second preset angular velocity, and the linear velocity of the auxiliary wheel is equal to the linear velocity of the expansion wheel, and there is no relative sliding between the expansion wheel and the fabric to be sewn.

[0026] Compared to the aforementioned background technology, the expansion mechanism provided by this invention has the following beneficial effects: First, the fabric to be sewn is placed onto the auxiliary wheel and the expansion wheel. Then, the expansion wheel is controlled to move along the first direction in stages, and the angular velocity is adjusted accordingly. This allows the tension of the upper segment of the fabric to be sewn and the tension of the upper and lower segments of the fabric to be sewn to be adjusted sequentially to preset values ​​and remain consistent. This effectively avoids wrinkles and uneven stitches during the sewing process, improving the sewing effect and the finished product qualification rate. Furthermore, the entire tension adjustment process of the fabric to be sewn does not require manual adjustment, reducing the difficulty and labor intensity of manual operation while improving the efficiency and accuracy of tension adjustment, thereby effectively enhancing the overall working efficiency of the expansion mechanism. The control method of the expansion mechanism used in this invention also possesses the above-mentioned beneficial effects. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is a plan view of the expansion mechanism provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the expansion wheel performing expansion motion according to an embodiment of the present invention.

[0030] Specifically, 1-sewing head; 2-expansion wheel; 3-auxiliary wheel; 4-fabric to be sewn; 401-lower layer segment; 402-upper layer segment; 5-tension detection device; 501-first mounting base; 502-first sensing probe; 503-upper lever; 504-first adjusting plate; 505-first elastic element; 506-second sensing probe; 507-lower lever; 508-second adjusting plate; 509-second elastic element. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 and Figure 2As shown, to achieve the above objectives, the present invention provides an expansion mechanism, comprising: a machine head 1 and an auxiliary wheel 3 and an expansion wheel 2 rotatably mounted on the machine head 1, wherein the expansion wheel 2 and the auxiliary wheel 3 are located in the same plane, and the rotation axis of the expansion wheel 2 is parallel to the rotation axis of the auxiliary wheel 3. The auxiliary wheel 3 and the expansion wheel 2 cooperate to fit the fabric 4 to be sewn. In specific applications, the auxiliary wheel 3 and the expansion wheel 2 can be driven to rotate clockwise around their own rotation axes to drive the fabric 4 to be sewn to rotate clockwise. A sewing mechanism is provided above the auxiliary wheel 3 and the expansion wheel 2. By controlling the auxiliary wheel 3 and the expansion wheel 2 to rotate clockwise, the fabric 4 to be sewn in the lower segment 401 can be moved to the upper segment 402 and passed through the sewing mechanism in sequence, whereby the sewing mechanism sews the fabric 4 to be sewn.

[0034] When expanding the fabric 4 to be sewn, the drive expansion wheel 2 is controlled to move away from the auxiliary wheel 3 along the first direction to tension the fabric 4. At the same time, the drive expansion wheel 2 is controlled to rotate positively around its own axis of rotation to further tension the fabric 4 to be sewn in the lower segment 401. This ensures that the tension of the fabric 4 to be sewn in the lower segment 401 and the fabric 4 to be sewn in the upper segment 402 reaches the preset value and remains consistent. By first placing the fabric 4 to be sewn onto the auxiliary wheel 3 and the expansion wheel 2, and then controlling the expansion wheel 2 to move along the first direction in stages and coordinating with angular velocity adjustment, the tension of the fabric 4 to be sewn in the upper segment 402 and the tension of the fabric 4 to be sewn in the lower and upper segments 402 are adjusted to the preset value and remain consistent. This effectively avoids wrinkles and uneven stitches in the fabric 4 during sewing, improving the sewing effect and the finished product qualification rate. It should be noted that the entire tension adjustment process of the fabric 4 to be sewn does not require manual adjustment, reducing the difficulty and labor intensity of manual operation while improving the efficiency and accuracy of tension adjustment of the fabric 4 to be sewn, thereby effectively improving the working efficiency of the overall expansion mechanism. The first direction is referenced in the appendix. Figure 1 and attached Figure 2 In the X direction; the direction of the expansion wheel 2's positive rotation around its own axis of rotation is shown in the attached reference. Figure 2 Central W direction; Appendix Figure 1 The diagram in the middle A represents the lower layer 401 fabric 4 to be sewn in an unstressed state.

[0035] When the expansion mechanism is in use, the fabric 4 to be sewn is placed on the auxiliary wheel 3 and the expansion wheel 2; the expansion wheel 2 is controlled to move away from the auxiliary wheel 3 in the first direction at a preset speed, and the expansion wheel 2 is controlled to rotate in the positive direction with its own rotation axis as the center at a first preset angular velocity until the tension of the fabric 4 to be sewn in the upper segment 402 reaches the preset value. At this time, there is no relative slippage between the expansion wheel 2 and the fabric 4 to be sewn, and the fabric 4 to be sewn in the lower segment 401 is automatically brought to the upper segment 402 to ensure that the tension of the fabric 4 to be sewn in the upper segment 402 is basically the same as the tension of the fabric 4 to be sewn in the lower segment 401. Continue to control the expansion wheel 2 to move away from the auxiliary wheel 3 along the first direction at a preset speed, and adjust the angular velocity of the expansion wheel 2 in real time to keep the tension of the fabric 4 to be sewn in the upper segment 402 constant, and make the tension of the fabric 4 to be sewn in the lower segment 401 reach the preset value and keep it consistent with the tension of the fabric 4 to be sewn in the upper segment 402. Finally, control the expansion wheel 2 to stop moving and rotating, and wait for the fabric 4 to be sewn to be sewn.

[0036] In some embodiments of the present invention, the sewing head 1 is also provided with a tension detection device 5, which monitors the tension of the fabric 4 to be sewn in the lower segment 401 and the fabric 4 to be sewn in the upper segment 402 in real time. This provides data support for the movement state and angular velocity adjustment of the expansion wheel 2, ensuring that the tension of the fabric 4 to be sewn in the upper segment 402 is consistent with and stable at a preset value as the tension of the fabric 4 to be sewn in the upper and lower segments 401, effectively ensuring improved fabric sewing effect and finished product qualification rate.

[0037] In some specific embodiments, the tension detection device 5 includes a mounting base disposed on the machine head 1. A first sensing probe 502 and an upper lever 503 are mounted on the mounting base. The lower end of the upper lever 503 is rotatably connected to the mounting base, and the upper end of the upper lever 503 abuts against the inner surface of the fabric 4 to be sewn in the upper layer segment 402. By utilizing the contact between the upper end of the upper lever 503 and the inner surface of the fabric 4 to be sewn in the upper layer segment 402, and the first sensing probe 502 monitoring the height position of the upper lever 503, the tension value of the fabric 4 to be sewn in the upper layer segment 402 is accurately captured. It should be noted that when the tension of the fabric 4 to be sewn changes, it will cause the upper lever 503 to rotate around the mounting base. The shift in the height position of the upper lever 503 can be captured in real time by the first sensing probe 502 and converted into an intuitive tension-related signal, achieving non-contact and accurate monitoring of the tension of the fabric in the upper layer segment 402, avoiding damage or interference to the fabric surface caused by direct contact. Furthermore, it provides reliable data for subsequent phased adjustment of the movement state and angular velocity of the expansion wheel 2, effectively ensuring that the tension of the fabric 4 to be sewn in the upper segment 402 accurately reaches the preset value and is maintained stably.

[0038] In some specific embodiments, a first adjusting plate 504 is slidably mounted on the mounting base. The length direction of the first adjusting plate 504 is consistent with the first direction. An upper lever 503 is connected to the first adjusting plate 504 through a first elastic element 505, wherein the first elastic element 505 is a tension spring. A first mounting hole is provided in the middle part of the upper lever 503. The left end of the first elastic element 505 is hooked in the first mounting hole, and the right end of the first elastic element 505 is connected to the first adjusting plate 504. By controlling the drive of the first adjusting plate 504 to reciprocate along the first direction and lock it in the stop position, the extension and retraction stroke of the first elastic element 505 can be adjusted. According to the different tension requirements of the fabric 4 to be sewn with different materials and thicknesses, the extension and retraction state of the first elastic element 505 can be flexibly adjusted, thereby adjusting the pre-tension force of the upper lever 503 against the upper layer segment 402 fabric, so that the tension detection device 5 can be adapted to various specifications of fabric, effectively improving the versatility of the overall tension detection device 5. On the other hand, by precisely adjusting the extension and retraction stroke of the first elastic element 505, the sensitivity of the upper lever 503 to changes in fabric tension can be improved, ensuring that the first sensing probe 502 can more accurately and timely capture the subtle fluctuations in the tension of the fabric 4 to be sewn, providing more reliable feedback data for the subsequent movement of the expansion wheel 2 and the adjustment of angular velocity, further improving the accuracy of tension control of the fabric 4 to be sewn in the upper segment 402, thereby reducing problems such as fabric wrinkles and uneven stitches caused by tension deviation.

[0039] In some specific embodiments, the tension detection device 5 further includes: a second sensing probe 506 and a lower lever 507 disposed on the mounting base. The upper end of the lower lever 507 is rotatably connected to the mounting base, and the lower end of the lower lever 507 abuts against the inner surface of the fabric 4 to be sewn in the lower layer segment 401. By utilizing the contact between the lower end of the lower lever 507 and the inner surface of the fabric 4 to be sewn in the lower layer segment 401, and the second sensing probe 506 monitoring the height position of the lower lever 507, the tension value of the fabric 4 to be sewn in the lower layer segment 401 is accurately captured. This, in conjunction with the first sensing probe 502, accurately captures the tension value of the fabric 4 to be sewn in the upper layer segment 402, thereby achieving the monitoring of the tension of the fabric 4 to be sewn in the upper layer segment 402 and... The synchronous and independent monitoring of the tension of the fabric 4 to be sewn in the lower segment 401 accurately captures the tension of the fabric 4 to be sewn in the upper segment 402 and the lower segment 401, respectively. This provides a reference for subsequent staged adjustment of the movement state and angular velocity of the expansion wheel 2, ensuring that the tension of the fabric 4 to be sewn in the upper segment 402 and the lower segment 401 can reach the preset value sequentially and remain consistent. This effectively avoids fabric wrinkles, uneven stitches, and other issues caused by inconsistent or unmet preset values ​​in the tension of the fabric 4 to be sewn in the upper segment 402 and the lower segment 401, thus effectively improving the processing accuracy and finished product qualification rate of the sewn products.

[0040] In some specific embodiments, a second adjusting plate 508 is slidably disposed under the mounting base. The length direction of the second adjusting plate 508 is consistent with the first direction. A lower lever 507 is connected to the second adjusting plate 508 through a second elastic element 509, wherein the second elastic element 509 is a tension spring. A second mounting hole is provided in the middle part of the lower lever 507. The right end of the second elastic element 509 is hooked in the second mounting hole, and the left end of the second elastic element 509 is connected to the second adjusting plate 508. By controlling the drive of the second adjusting plate 508 to reciprocate along the first direction and lock it in the stop position, the extension and retraction stroke of the second elastic element 509 can be adjusted. Similarly, according to the different tension requirements of the fabric 4 to be sewn with different materials and thicknesses, the extension and retraction state of the second elastic element 509 can be flexibly adjusted, thereby adjusting the pre-tension force of the lower lever 507 against the lower layer segment 401 fabric, so that the tension detection device 5 can be adapted to various specifications of fabric, effectively improving the versatility of the overall tension detection device 5. On the other hand, by precisely adjusting the extension and retraction stroke of the second elastic element 509, the sensitivity of the lower lever 507 to changes in fabric tension can be improved, ensuring that the second sensing probe 506 can more accurately and promptly capture subtle fluctuations in the tension of the fabric 4 to be sewn. This provides more reliable feedback data for the subsequent movement of the expansion wheel 2 and adjustment of its angular velocity, further improving the accuracy of tension control of the fabric 4 to be sewn in the lower segment 401, thereby reducing problems such as fabric wrinkles and uneven stitches caused by tension deviations. Furthermore, by monitoring the height position of the upper lever 503 with the first sensing probe 502 and the height position of the lower lever 507 with the second sensing probe 506, synchronous and independent monitoring of the tension of the fabric 4 to be sewn in the upper segment 402 and the lower segment 401 can be achieved, further providing a precise basis for subsequent staged adjustment of the movement state and angular velocity of the expansion wheel 2.

[0041] It should be noted that when the length direction of the upper lever 503 is perpendicular to the first direction, the upper end of the upper lever 503 is at the upper limit position. When the length direction of the lower lever 507 is perpendicular to the first direction, the lower end of the lower lever 507 is at the lower limit position. This ensures that during the expansion mechanism's expansion of the fabric 4 to be sewn, the upper lever 503 can stably abut against the inner side of the fabric 4 to be sewn in the upper segment 402, and the lower lever 507 can stably abut against the inner side of the fabric 4 to be sewn in the lower segment 401. At the same time, it ensures that the upper lever 503 and the lower lever 507 maintain a reasonable support angle and contact state during the tension adjustment of the fabric 4 to be sewn in the upper segment 402 and the lower segment 401, respectively. This is to cooperate with the first sensing probe 502 and the second sensing probe 506 to accurately capture the tension fluctuations of the fabric 4 to be sewn, providing a more reliable basis for the movement of the expansion wheel 2 and the adjustment of its angular velocity.

[0042] In addition to the aforementioned expansion mechanism, this invention also provides a hem machine including a sewing mechanism and the expansion mechanism disclosed in the above embodiments. The structures of other parts of this hem machine are described in the prior art and will not be repeated here. After the expansion mechanism controls the tension of the fabric 4 to be sewn in the upper segment 402 to be consistent with and stable at a preset value in both the upper and lower segments 401, it controls the drive auxiliary wheel 3 and the expansion wheel 2 to rotate clockwise. This moves the fabric 4 to be sewn in the lower segment 401 to the upper segment 402 and sequentially through the sewing mechanism, whereby the sewing mechanism sews the fabric 4.

[0043] The control method of the expansion mechanism adopted in this invention specifically includes the following steps: placing the fabric 4 to be sewn onto the auxiliary wheel 3 and the expansion wheel 2; controlling the drive expansion wheel 2 to move away from the auxiliary wheel 3 along a first direction at a preset speed, and controlling the drive expansion wheel 2 to rotate positively around its own rotation axis at a first preset angular velocity until the tension of the fabric 4 to be sewn in the upper segment 402 reaches a preset value; continuing to control the drive expansion wheel 2 to move away from the auxiliary wheel 3 along the first direction at a preset speed, and adjusting the angular velocity of the expansion wheel 2 in real time to keep the tension of the fabric 4 to be sewn in the upper segment 402 constant, and to make the tension of the fabric 4 to be sewn in the lower segment 401 reach a preset value and be consistent with the tension of the fabric 4 to be sewn in the upper segment 402; finally controlling the expansion wheel 2 to stop moving and rotating, waiting for the fabric 4 to be sewn to be sewn.

[0044] In some specific embodiments, the steps of controlling the drive expansion wheel 2 to move away from the auxiliary wheel 3 along a first direction at a preset speed, and controlling the drive expansion wheel 2 to rotate positively around its own rotation axis at a first preset angular velocity, include: substituting the speed of the expansion wheel 2 moving away from the auxiliary wheel 3 along the first direction and the radius of the expansion wheel 2 into the angular velocity calculation formula to obtain the angular velocity of the expansion wheel 2 rotating positively around its own rotation axis. The angular velocity calculation formula is as follows: Where W represents the angular velocity of the expanding wheel 2 rotating positively about its own axis of rotation; V represents the velocity of the expanding wheel 2 moving away from the auxiliary wheel 3 along the first direction; and R represents the radius of the expanding wheel 2. The angular velocity is calculated by substituting the velocity V of the expanding wheel 2 along the first direction and the radius R of the expanding wheel 2 into the formula. The first preset angular velocity of the expansion wheel 2's forward rotation is obtained, and this is used to control the expansion wheel 2 to synchronously achieve the preset speed of movement and the first preset angular velocity of rotation. This ensures that there is no relative slippage between the expansion wheel 2 and the fabric 4 to be sewn, thereby achieving automatic synchronous feeding of the fabric 4 to be sewn from the lower segment 401 to the upper segment 402. This avoids tension deviations caused by asynchronous feeding of the fabric 4 to be sewn, ensuring that the tension of the fabric 4 to be sewn in the upper segment 402 is basically consistent with that in the lower segment 401 during the initial adjustment, providing a foundation for subsequent control. At the same time, since there is no relative slippage between the expansion wheel 2 and the fabric 4 to be sewn, frictional damage between the fabric 4 to be sewn and the expansion wheel 2 is reduced, effectively protecting the surface quality of the fabric 4 to be sewn.

[0045] In some specific embodiments, before the tension of the fabric 4 to be sewn in the upper segment 402 reaches a preset value, the method further includes: controlling the drive auxiliary wheel 3 to rotate positively around its own axis of rotation at a second preset angular velocity, and ensuring that the linear velocity of the auxiliary wheel 3 is equal to the linear velocity of the expansion wheel 2, with no relative slippage between the expansion wheel 2 and the fabric 4 to be sewn. By controlling the auxiliary wheel 3 to rotate positively at the second preset angular velocity and ensuring that its linear velocity is consistent with that of the expansion wheel 2, the key to this design is to further avoid relative friction or pulling between the fabric 4 to be sewn and the expansion wheel 2 and / or the auxiliary wheel 3 during the conveying process, effectively reducing fabric surface wear and tensile deformation, and providing a stable motion basis for the fabric 4 to be sewn in the upper segment 402 to accurately reach the preset value.

[0046] In summary, before sewing the fabric 4 to be sewn, the fabric 4 to be sewn is first placed on the auxiliary wheel 3 and the expansion wheel 2. Then, the expansion wheel 2 is controlled to move along the first direction in stages and the angular velocity is adjusted in conjunction with the control. This allows the tension of the fabric 4 to be sewn in the upper segment 402 and the tension of the fabric 4 to be sewn in the lower and upper segments 402 to be adjusted to the preset values ​​and kept consistent. This effectively avoids wrinkles and uneven stitches in the fabric 4 to be sewn during the sewing process, thereby improving the sewing effect and the finished product qualification rate.

[0047] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0048] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. An expansion mechanism, characterized in that, include: The machine head (1) and the auxiliary wheel (3) and the expansion wheel (2) rotatably mounted on the machine head (1), the auxiliary wheel (3) and the expansion wheel (2) cooperating to fit the fabric (4) to be sewn. The auxiliary wheel (3) can be driven to rotate in the positive direction around its own axis of rotation, so as to drive the fabric (4) to be sewn to rotate in the positive direction; The expansion wheel (2) can be driven to move away from the auxiliary wheel (3) in the first direction to tension the fabric (4) to be sewn. The expansion wheel (2) can also be driven to rotate in the positive direction around its own axis of rotation to further tension the fabric (4) to be sewn in the lower segment (401), so that the tension of the fabric (4) to be sewn in the lower segment (401) and the fabric (4) to be sewn in the upper segment (402) reaches a preset value in sequence and remains consistent.

2. The expansion mechanism according to claim 1, characterized in that, A tension detection device (5) is also provided. The tension detection device (5) includes: a mounting base provided on the machine head (1), a first sensing probe (502) and an upper lever (503) provided on the mounting base, the first end of the upper lever (503) being rotatably connected to the mounting base, and the second end of the upper lever (503) abutting against the inner side of the fabric (4) to be sewn in the upper layer segment (402). The first sensing probe (502) is used to monitor the height position of the upper lever (503).

3. An expansion mechanism according to claim 2, characterized in that, The first adjusting plate (504) is slidably disposed on the mounting base. The upper lever (503) is connected to the first adjusting plate (504) through the first elastic element (505). The first adjusting plate (504) can be driven to reciprocate along the first direction to adjust the extension and retraction stroke of the first elastic element (505).

4. An expansion mechanism according to claim 3, characterized in that, The tension detection device (5) further includes: a second sensing probe (506) and a lower lever (507) disposed on the mounting base. The first end of the lower lever (507) is rotatably connected to the mounting base, and the second end of the lower lever (507) abuts against the inner side of the fabric (4) to be sewn in the lower layer segment (401). The second sensing probe (506) is used to monitor the height position of the lower lever (507).

5. An expansion mechanism according to claim 4, characterized in that, The second adjustment plate (508) is slidably disposed on the mounting base. The lower lever (507) is connected to the second adjustment plate (508) through the second elastic element (509). The second adjustment plate (508) can be driven to reciprocate along the first direction to adjust the extension and retraction stroke of the second elastic element (509).

6. An expansion mechanism according to claim 5, characterized in that, When the length direction of the upper lever (503) is perpendicular to the first direction, the end of the second end of the upper lever (503) is located at the upper limit position. When the length direction of the lower lever (507) is perpendicular to the first direction, the end of the second end of the lower lever (507) is located at the lower limit position.

7. A hem-down machine, characterized in that, It includes a sewing mechanism and an expansion mechanism as described in any one of claims 1-6.

8. A control method for an expansion mechanism, applied to the expansion mechanism according to any one of claims 1-6, characterized in that, The control method includes: The fabric (4) to be sewn is placed on the auxiliary wheel (3) and the expansion wheel (2); Control the expansion wheel (2) to move away from the auxiliary wheel (3) along the first direction at a preset speed, and control the expansion wheel (2) to rotate in the positive direction with its own rotation axis as the center at a first preset angular velocity until the tension of the fabric (4) to be sewn in the upper segment (402) reaches the preset value; Continue to control the expansion wheel (2) to move away from the auxiliary wheel (3) along the first direction at a preset speed, and adjust the angular velocity of the expansion wheel (2) in real time so that the tension of the fabric (4) to be sewn in the upper segment (402) remains unchanged, and the tension of the fabric (4) to be sewn in the lower segment (401) reaches a preset value and is consistent with the tension of the fabric (4) to be sewn in the upper segment (402).

9. The control method for an expansion mechanism according to claim 8, characterized in that, The steps of controlling and driving the expansion wheel (2) to move away from the auxiliary wheel (3) along the first direction at a preset speed, and controlling and driving the expansion wheel (2) to rotate in the positive direction with its own rotation axis as the center at a first preset angular velocity, include: Substituting the speed of the expanding wheel (2) moving away from the auxiliary wheel (3) along the first direction and the radius of the expanding wheel (2) into the angular velocity calculation formula, the angular velocity of the expanding wheel (2) rotating positively around its own axis of rotation is obtained. The angular velocity calculation formula is: ； in, W represents the angular velocity of the expansion wheel (2) when it rotates in the positive direction with its own axis of rotation as the center; V represents the speed at which the expansion wheel (2) moves away from the auxiliary wheel (3) along the first direction; R represents the radius of the expansion wheel (2).

10. The control method for an expansion mechanism according to claim 8, characterized in that, Before the step of reaching a preset value in the tension of the fabric (4) to be sewn in the upper segment (402), the method further includes: controlling the auxiliary wheel (3) to rotate in the positive direction with its own rotation axis as the center at a second preset angular velocity, and the linear velocity of the auxiliary wheel (3) is equal to the linear velocity of the expansion wheel (2), and there is no relative sliding between the expansion wheel (2) and the fabric (4) to be sewn.

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