Middle presser foot mechanism and sewing equipment

Abstract

A middle presser foot mechanism and sewing equipment are characterized in that a driving structure is connected with a middle presser foot through a slider-crank mechanism, so that the middle presser foot completes cyclic reciprocating action and executes a target middle presser foot stroke; a motion transmission piece at the upper part of the middle presser foot penetrates through the top of the machine shell, and a sliding pair is formed between the motion transmission piece and the machine shell; an execution part on the lower portion of the middle presser foot penetrates through the bottom of the machine shell, and a sliding pair is formed between the execution part and the machine shell. An induction plate is arranged on the slider-crank mechanism, and the limit position of the middle presser foot is obtained through the induction plate and a matched inductor; the sewing equipment comprises a control unit, a spindle motor, a middle presser foot motor and a feeding motor, and the control unit is used for controlling rotation of the spindle motor, the middle presser foot motor and the feeding motor according to the target pattern parameters.

Description

Technical Field

[0001] This utility model belongs to the technical field of presser foot in sewing machines, specifically relating to a presser foot mechanism and sewing equipment. Background Technology

[0002] The presser foot mechanism, also known as the presser foot device, is an important component of a sewing machine, mainly used to control the raising and lowering of the presser foot. It is usually located above the needle plate of the sewing machine, and its function is to provide appropriate pressure to the fabric, ensuring that the fabric does not become excessively loose, slip, or deformed during sewing.

[0003] The main function of the presser foot is to help control the flatness of the fabric and the quality of the stitching by adjusting the pressure of the presser foot. It usually works in conjunction with the presser foot mechanism, adjusting the height or weight of the presser foot to accommodate fabrics of different thicknesses or textures. For example, thicker fabrics require higher pressure to maintain fabric stability, while thinner or slippery fabrics require lower pressure to avoid deforming or overstretching the fabric.

[0004] The working requirements of the pressure foot mechanism include the following aspects:

[0005] Apply uniform pressure: Ensure the fabric passes steadily through the sewing machine during the sewing process;

[0006] By adjusting the pressure and the height of the dead point under the medium pressure foot, it can adapt to fabrics of different thicknesses and materials, avoiding problems such as skipped stitches and broken threads;

[0007] To prevent fabric deformation: By using appropriate pressure and the height of the dead point under the medium pressure foot, problems such as fabric slippage due to excessive pressure during sewing can be prevented.

[0008] Currently, the commonly used medium pressure foot mechanism is generally driven by a spindle connected to a main spindle motor to move the pressure foot up and down, and then another motor drives the change of the lower dead center of the pressure foot. The problems with this mechanism are: complex structure and inability to change the follow-up stroke during movement. These problems urgently need to be solved. Utility Model Content

[0009] The purpose of this utility model is to provide a medium pressure foot mechanism. The drive structure is connected to the medium pressure foot through a crank-slider mechanism, so that the medium pressure foot completes a cyclic reciprocating motion and executes the target medium pressure foot stroke. The motion transmission component at the upper part of the medium pressure foot passes through the top of the housing, and a sliding pair is formed between the motion transmission component and the housing. The execution component at the lower part of the medium pressure foot passes through the bottom of the housing, and a sliding pair is formed between the execution component and the housing.

[0010] The technical solution provided in this application also has the following technical features:

[0011] Preferably, in one embodiment of this application, a sensing plate and a matching sensor are provided on the crank-slider mechanism to obtain the extreme position of the pressure foot.

[0012] Preferably, in one embodiment of this application, an adjustment device is provided on the middle pressure foot so that the lower limit position of the middle pressure foot is adjustable. The lower limit position of the middle pressure foot can be adjusted mechanically, such as by using a fisheye connecting rod for the adjustment device.

[0013] The fisheye connecting rod includes a fisheye connector and a connecting rod assembly. One end is the fisheye connector, and the other end is a threaded connection. It is used to connect different mechanical components to achieve the purpose of mechanical adjustment.

[0014] Preferably, in one embodiment of this application, the driving structure includes a driving source, which is a motor.

[0015] Preferably, in one embodiment of this application, the drive source is mounted on the housing via a support structure, one end of the drive crank is connected to the output shaft of the drive source, and the other end of the drive crank is connected to the connector A via fastener E; the connector A is threadedly connected to one end of the motion transmission component and locked by fastener A; the other end of the motion transmission component is threadedly connected to the connector B and locked by fastener D.

[0016] Connector B is connected to guide component via fastener B and fastener C; guide component is mounted on actuator, actuator moves up and down in auxiliary assembly, and working component is fixed at the lower end of actuator.

[0017] Preferably, in one embodiment of this application, a sewing device applies the above-mentioned presser foot mechanism, including a control unit, a spindle motor, a presser foot motor, and a feed motor. The control unit controls the rotation of the spindle motor, the presser foot motor, and the feed motor according to the target pattern parameters.

[0018] Preferably, in one embodiment of this application, the control unit is equipped with a display panel for setting the pattern target parameters.

[0019] Preferably, in one embodiment of this application, the drive source rotates clockwise, causing the drive crank to rotate clockwise around the drive source shaft; the drive crank then causes the connecting member A to rise, and transmits the motion to the motion transmission member, connecting member B, guide member, execution member, and working member in sequence, so that the working member is raised;

[0020] The drive source rotates counterclockwise, causing the working part to descend; the drive source oscillates back and forth, causing the working part to follow when it moves up and down at a certain amplitude; the lower limit height and stroke of the follow-up movement are adjustable; when sewing ends, the working part is raised to the preset highest point, and when the working part is raised to the highest point, the sensing element is in the sensing area of ​​the detection feedback component.

[0021] Preferably, in one embodiment of this application, connector A is a fisheye connector A, and connector B is a fisheye connector B.

[0022] Preferably, in one embodiment of this application, fasteners A, B, E, and C are threaded components.

[0023] Preferably, in one embodiment of this application, a medium pressure foot mechanism is provided, wherein a motor is mounted on a housing via a bracket, one end of a drive crank is connected to the output shaft of the motor, and the other end of the drive crank is connected to a fisheye connector A via a shaft screw; the fisheye connector A is threadedly connected to one end of a connecting rod and locked by a nut A; the other end of the connecting rod is threadedly connected to a fisheye connector B and locked by a nut B.

[0024] The actuating component is a pressure rod, the guiding component is a pressure rod guide frame, the auxiliary component is a pressure rod bushing, and the working component is a middle pressure foot. Fisheye connector B is connected to the pressure rod guide frame via locking screws and locking nuts. The pressure rod guide frame is mounted on the pressure rod, which moves up and down within the pressure rod bushing. The lower end of the pressure rod is fixed with a middle pressure foot. The pressure rod guide frame serves to guide and restrict the radial rotation of the pressure rod.

[0025] A sensor plate is installed on the drive crank; the sensor is fixed on the bracket; when the presser foot is raised to the highest point, the sensor plate is above the sensor sensing area;

[0026] When the motor rotates clockwise, it drives the drive crank to rotate clockwise around the motor shaft; the drive crank then drives the fisheye joint A to rise, and transmits this to the connecting rod, fisheye joint B, pressure rod guide, pressure rod, and middle presser foot in sequence, causing the middle presser foot to rise; conversely, when the motor rotates counterclockwise, the middle presser foot falls; the motor oscillates back and forth, and when the middle presser foot moves up and down at a certain amplitude, it constitutes the follow-up movement of the middle presser foot; the lower limit height of the follow-up movement can be varied, and the amplitude of the follow-up movement, i.e., the follow-up stroke, can also be varied; when the sewing is finished, the middle presser foot is raised to the preset highest point; the detection feedback component is a sensor, and the sensing element is a sensing plate; when the middle presser foot is raised to the highest point, the sensor should be able to sense the sensing plate.

[0027] A method for controlling a middle presser foot mechanism includes the following steps: the control unit controls the rotation of the spindle motor, the middle presser foot motor, and the feed motor according to the target pattern parameters, and the spindle motor, the middle presser foot motor, and the feed motor are equipped with their own independent timing and input parameters to obtain the target sewing stitch.

[0028] The control unit sets the target parameters of the pattern via the display panel; the control unit obtains the given pressing angle range from the desired pressing angle range based on the fabric thickness and sewing speed.

[0029] The control unit obtains the given presser foot stroke from the desired presser foot stroke based on the fabric thickness and presser foot height.

[0030] The height of the middle pressure foot is the lower limit height of the middle pressure foot movement;

[0031] Medium pressure foot stroke: the difference between the highest and lowest points of the medium pressure foot during follow-up movement;

[0032] The given pressure angle range is the range of spindle motor angles from when the control unit issues the start-pressing command to when the control unit issues the completion-lifting command.

[0033] The desired pressure angle range is the range of the spindle motor angle from when the pressure mechanism starts to press down to when it completes the lifting.

[0034] The technical solution provided in this application also has the following technical features:

[0035] Preferably, in one embodiment of this application, the pattern target parameters include the sewing speed and presser foot height in the pattern.

[0036] Preferably, in one embodiment of this application, the pattern parameters include at least the data for stitch length, sewing speed, presser foot height, and thread tension.

[0037] Preferably, in one embodiment of this application, the pattern parameters further include one or more of the following: needle width, pattern type, pattern density, pattern length, pattern alignment, pattern direction, pattern repetition count, reverse pattern, elastic pattern, and automatic pattern adjustment data.

[0038] Preferably, in one embodiment of this application, different fabric thicknesses and sewing speeds are preset, along with corresponding desired pressure angle ranges.

[0039] Preferably, in one embodiment of this application, the given pressure angle range includes the pressing process and the lifting process of the middle pressure foot.

[0040] Preferably, in one embodiment of this application, different fabric thicknesses and pressure foot heights are preset to correspond to desired pressure foot strokes.

[0041] Preferably, in one embodiment of this application, the instruction for the angle of the middle pressure foot motor is given by the timing curve of the angle of the middle pressure foot motor.

[0042] Preferably, in one embodiment of this application, the stroke of the middle pressure foot is achieved by the angle of the middle pressure foot motor, and the motor angle at the lowest point and the motor angle at the highest point of the middle pressure foot are determined according to the fabric thickness and the height of the middle pressure foot.

[0043] set up:

[0044] Angle A represents the angle of the spindle motor when the control unit issues the command to start pressing down;

[0045] Angle B represents the angle of the spindle motor when the control unit issues the command to end the downward pressure.

[0046] Angle C represents the angle of the spindle motor when the control unit issues the start-lift command;

[0047] Angle D represents the angle of the spindle motor when the control unit issues the end lifting command;

[0048] Angle E represents the angle of the spindle motor when the middle pressure foot actually reaches its highest point;

[0049] Angle F represents the angle of the spindle motor when the middle pressure foot actually reaches its lowest point;

[0050] Angle G represents the spindle motor angle at which the middle pressure foot is expected to reach its highest point;

[0051] Angle H represents the spindle motor angle at which the middle pressure foot is expected to reach its lowest point;

[0052] Angle I represents the angle of the middle pressure foot motor at the highest point of the middle pressure foot, given by the control unit;

[0053] Angle J represents the angle of the middle pressure foot motor at the lowest point of the middle pressure foot, as given by the control unit.

[0054] Preferably, in one embodiment of this application, the advance angle K represents the spindle motor angle at which the desired middle pressure foot reaches its highest point and the spindle motor angle at which the control unit issues the end lifting command; that is, advance angle K = angle G - angle D;

[0055] The advance angle L represents the angle of the spindle motor when the desired middle pressure foot reaches its lowest point and the angle of the spindle motor when the control unit issues the end-pressing command; that is, advance angle L = angle H - angle B.

[0056] Preferably, in one embodiment of this application, the main spindle motor is used to control the material feeding and the rotary hook hooking;

[0057] The intermediate pressure foot motor is used to control the material pressing by the intermediate pressure foot;

[0058] The feeding motor is used to control the movement of the X / Y axes for feeding.

[0059] The main spindle motor, the intermediate pressure foot motor, and the feed motor are controlled independently, allowing the timing and input parameters to be adjusted during the sewing process.

[0060] Preferably, in one embodiment of this application, the control unit completes the sewing operation through the main spindle motor, the middle presser foot motor, and the feed motor, so that the middle presser foot completes the corresponding action.

[0061] Preferably, in one embodiment of this application, the input parameters, including fabric thickness, number of layers, etc., are automatically adjusted during the sewing process.

[0062] Preferably, in one embodiment of this application, the presser foot synchronization, bottom dead center height, and follow-up stroke are adjusted in the slow-down sewing area.

[0063] Preferably, in one embodiment of this application, during the sewing process, the control unit reads the pattern information and determines that the sewing speed of a certain section is significantly reduced, while the height of the presser foot is significantly increased, thereby determining that the fabric has been sewn to an area that is too thick;

[0064] If the pattern only sets the sewing speed to decrease while the presser foot height remains unchanged, it cannot be determined that the area being sewn is too thick.

[0065] When the thickness is determined to be too thick, the control program automatically advances angles A and B according to the preset reference parameters based on the sewing speed and the height of the middle presser foot. That is, by advancing the spindle motor angles that the control unit issues the start pressing command and the spindle motor angles that the control unit issues the end pressing command, the desired spindle motor angles that bring the middle presser foot to its lowest point are achieved.

[0066] Preferably, in one embodiment of this application, angles I and J are adjusted according to the set height of the middle pressure foot, while the difference between angles J and I is increased. That is, the height of the middle pressure foot is increased, and the stroke of the middle pressure foot is increased.

[0067] Preferably, in one embodiment of this application, the adjustment of angles I and J is performed according to the different pressure foot heights and pressure foot motor angles pre-set in the control program.

[0068] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0069] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0070] Figure 1 This utility model provides a three-dimensional pressure foot mechanism. Figure 1 ;

[0071] Figure 2 This utility model provides a three-dimensional pressure foot mechanism. Figure 2 ;

[0072] Figure 3 This is a schematic diagram of a control method for a pressure foot mechanism according to the present invention;

[0073] Figure 4 This is a timing diagram of the angle of the middle pressure foot motor in a control method for a middle pressure foot mechanism according to this utility model;

[0074] Figure 5 This is a flowchart of a control method for a pressure foot mechanism according to the present invention;

[0075] Components in the diagram:

[0076] 1. Supporting structural components

[0077] 2. Driver source

[0078] 3. Drive crank

[0079] 4. Detection Feedback Component

[0080] 5. Sensing element

[0081] 6. Connector A

[0082] 7. Fastener A

[0083] 8. Motion transmission components

[0084] 9. Fastener B

[0085] 10. Guide components

[0086] 11. Actuating Components

[0087] 12. Auxiliary Components

[0088] 13. Working parts

[0089] 14. Housing

[0090] 15. Fastener E

[0091] 16. Fastener C

[0092] 17. Connector B

[0093] 18. Fastener D. Detailed Implementation

[0094] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings. These embodiments are only for illustrating this application and are not intended to limit the scope of this utility model.

[0095] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0096] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0097] Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0098] like Figure 1 , 2 A medium pressure foot mechanism is provided, wherein the drive structure is connected to the medium pressure foot through a crank-slider mechanism, so that the medium pressure foot completes a cyclic reciprocating motion to execute the target medium pressure foot stroke; the motion transmission member 8 at the upper part of the medium pressure foot passes through the top of the housing 14, and a sliding pair is formed between the motion transmission member 8 and the housing 14; the actuating member 11 at the lower part of the medium pressure foot passes through the bottom of the housing 14, and a sliding pair is formed between the actuating member 11 and the housing 14.

[0099] In this application, the supporting structure 1 adopts a bracket structure, the drive source 2 is a motor; the detection feedback component 4 is a sensor, the sensing element 5 is a sensing plate, the connector A6 is a fisheye connector A, the fastener A7 is a nut A, the motion transmission component 8 is a connecting rod, the fastener B9 is a locking screw, the guide component 10 is a pressure rod guide frame, the execution component 11 is a pressure rod, the auxiliary component 12 is a pressure rod bushing, the working component 13 includes a middle pressure foot, 14 is a housing, the fastener E15 is a shaft screw, the fastener C16 is a locking nut, the connector B17 is a fisheye connector B, and the fastener D18 is a nut B.

[0100] Specifically, in one embodiment of this application, a sensing plate and a matching sensor are provided on the crank-slider mechanism to obtain the extreme position of the pressure foot.

[0101] Specifically, in one embodiment of this application, an adjustment device is provided on the middle pressure foot to make the lower limit position of the middle pressure foot adjustable. The lower limit position of the middle pressure foot can be adjusted mechanically, such as by using a fisheye connecting rod for the adjustment device.

[0102] The fisheye connecting rod includes a fisheye connector and a connecting rod assembly. One end is the fisheye connector, and the other end is a threaded connection. It is used to connect different mechanical components to achieve the purpose of mechanical adjustment.

[0103] Specifically, in one embodiment of this application, the driving structure includes a driving source 2, which is a motor.

[0104] Specifically, in one embodiment of this application, the drive source 2 is mounted on the housing 14 via a support structure 1. One end of the drive crank 3 is connected to the output shaft of the drive source 2, and the other end of the drive crank 3 is connected to the connector A6 via a fastener E15. The connector A6 is threadedly connected to one end of the motion transmission component 8 and locked by a fastener A7. The other end of the motion transmission component 8 is threadedly connected to the connector B17 and locked by a fastener D18.

[0105] Connector B17 is connected to guide component 10 via fastener B9 and fastener C16; guide component 10 is disposed on actuator 11, actuator 11 moves up and down in auxiliary component 12, and working component 13 is fixed at the lower end of actuator 11.

[0106] Specifically, in one embodiment of this application, the drive source 2 rotates clockwise, causing the drive crank 3 to rotate clockwise around the axis of the drive source 2; the drive crank 3 then causes the connecting member A6 to be lifted, and transmits the motion to the motion transmission member 8, the connecting member B17, the guide member 10, the execution member 11, and the working member 13 in sequence, so that the working member 13 is lifted.

[0107] The drive source 2 rotates counterclockwise, causing the working part 13 to descend; the drive source 2 oscillates back and forth, causing the working part 13 to follow the movement when it moves up and down at a certain amplitude; the lower limit height and the follow-up stroke of the follow-up movement are adjustable; when the sewing ends, the working part 13 is raised to the preset highest point, and when the working part 13 is raised to the highest point, the sensing element 5 is in the sensing area of ​​the detection feedback component 4.

[0108] Specifically, in one embodiment of this application, connector A6 is a fisheye connector A, and connector B17 is a fisheye connector B.

[0109] Specifically, in one embodiment of this application, fasteners A7, B9, E15, and C16 are threaded components.

[0110] A middle presser foot mechanism for a sewing machine, the usage process is as follows:

[0111] First, the drive source 2 is fixed to the housing 14 via the support structure 1. A drive crank 3 is mounted on the output shaft of the drive source 2, and the other end of the drive crank 3 is connected to the connector A6 via fastener E15. Connector A6 is threaded to the motion transmission component 8 and locked by fastener A7. The motion transmission component 8 has threads at both ends, and the other end is connected to connector B17 and locked by fastener D18. Connector B17 is then connected to the guide component 10 via fasteners B9 and C16. The guide component 10 is fixed to the actuating component 11, which moves up and down within the auxiliary assembly 12. A working component 13 is fixed to the lower end of the actuating component 11. The guide component 10 serves to guide and restrict the radial rotation of the actuating component 11.

[0112] Specifically, in one embodiment of this application, a sensing element 5 is fixed to the drive crank 3. A detection feedback assembly 4 is fixed to the support structure 1. When the pressure foot is raised to its highest point, the sensing element 5 is above the sensing area of ​​the detection feedback assembly 4. The sensing element 5, detection feedback assembly 4, and other related sensing components are not essential to this solution.

[0113] Specifically, in one embodiment of this application, the supporting structure 1, when the drive source 2 rotates clockwise, drives the drive crank 3 to rotate clockwise around the axis of the drive source 2. The drive crank 3 then drives the connecting member A6 to rise, and transmits the motion to the motion transmission member 8, connecting member B17, guide member 10, execution member 11, and working member 13 in sequence, causing the working member 13 to rise. Conversely, when the drive source 2 rotates counterclockwise, the working member 13 descends. The drive source 2 oscillates back and forth, and when the working member 13 moves up and down at a certain amplitude, it constitutes the follow-up motion of the working member 13. The lower limit height of the follow-up motion can vary, and the amplitude of the follow-up motion, i.e., the follow-up stroke, can also vary. When the sewing ends, the working member 13 is raised to the preset highest point. When the working member 13 is raised to the highest point, the detection feedback component 4 should be able to sense the sensing element 5.

[0114] This application provides a control method and structure for a medium pressure foot mechanism that is simple in structure, can vary its stroke during movement, has low motor load, and is easy to install and assemble.

[0115] Preferably, in one embodiment of this application, a sewing device applies the above-mentioned presser foot mechanism, including a control unit, a spindle motor, a presser foot motor, and a feed motor. The control unit controls the rotation of the spindle motor, the presser foot motor, and the feed motor according to the target pattern parameters.

[0116] Preferably, in one embodiment of this application, the control unit is equipped with a display panel for setting the pattern target parameters.

[0117] like Figure 3This application discloses a method for controlling a middle presser foot mechanism, wherein the control unit controls the rotation of the main spindle motor, the middle presser foot motor, and the feed motor according to the pattern, thereby controlling the sewing stitch.

[0118] The control unit is an electronic control system, consisting of a microprocessor, sensors, and drive circuits, which has a higher degree of intelligence and automation; the control unit of an electronic sewing machine is based on a microcontroller, such as an MCU, and implements complex logic control through programming;

[0119] The main spindle motor controls the thread take-up and the rotary hook hook, the middle presser foot motor controls the middle presser foot pressing the material, and the feed motor controls the X / Y axis movement for feeding. Because the three are controlled independently, the timing can be adjusted during the sewing process without having to wait until it stops. This allows the sewing machine to automatically adjust according to the fabric thickness, number of layers, etc., during the sewing process, thereby improving the quality of the sewing stitches.

[0120] Specifically, the control method of the middle presser foot mechanism includes: First, obtaining the sewing speed and middle presser foot height in the pattern; Second, determining the pressing angle range based on the fabric thickness and sewing speed; Third, determining the stroke of the middle presser foot based on the fabric thickness and middle presser foot height; Fourth, controlling the main spindle motor and the middle presser foot motor based on the above information.

[0121] The first step is to obtain the sewing speed and presser foot height for the pattern. The pattern parameters should include at least the stitch length, sewing speed, presser foot height, and thread tension, and all of these parameters can be set in segments. The sewing speed and presser foot height are determined based on the fabric material, single-layer thickness, and number of layers. The presser foot height is the lower limit height at which the presser foot moves. For example, when sewing a 3-layer denim fleece fabric, set the presser foot height to 2.5mm and the sewing speed to 3000rpm; when sewing a 10-layer denim fleece fabric, set the presser foot height to 7mm and the sewing speed to 1500rpm.

[0122] Appropriate presser foot pressure ensures that the fabric passes through smoothly and steadily during sewing; excessive pressure can cause the fabric to deform or sink, while insufficient pressure can cause the fabric to slide unstably, affecting the sewing quality.

[0123] Adaptable to different materials: Different types of fabrics (such as lightweight fabrics, heavy fabrics, elastic fabrics, etc.) require different presser foot pressures; heavy fabrics usually require greater pressure, while thin fabrics require less pressure; for elastic fabrics, special presser foot settings may also be required to prevent the fabric from stretching and deforming.

[0124] Thread tension refers to the tension of the sewing thread on a sewing machine; it is the balance of tension between the top thread and the bobbin thread, and is usually divided into top thread tension and bobbin thread tension; setting the tension too high or too low may affect the sewing quality.

[0125] Thread tension directly affects the tightness of the stitch; if the tension is too loose, it may cause loose threads or spots.

[0126] Sewing effect: Different fabrics, threads and sewing types require different thread tensions; for example, when using elastic thread, the thread tension needs to be adjusted appropriately to avoid thread breakage or uneven fabric stretching.

[0127] An imbalance will lead to the situation described above;

[0128] The pattern parameters may also include parameters such as needle width, pattern type, pattern density, pattern length, pattern alignment, pattern direction, number of pattern repetitions, reverse pattern, elastic pattern, and automatic pattern adjustment.

[0129] The second step is to obtain the given pressure angle range based on the fabric thickness and sewing speed. The program needs to preset the desired pressure angle range for different fabric thicknesses and sewing speeds. Therefore, during execution, the given pressure angle range is obtained from the desired pressure angle range based on the fabric thickness and sewing speed.

[0130] When the motor-driven mechanism moves, it takes a certain amount of time to complete the response after the control unit issues a command. Therefore, the pressure angle range is defined as the given pressure angle range.

[0131] Compared to the desired pressing angle range, the given pressing angle range corresponds to the spindle motor angle for which the control unit issues the corresponding command, while the desired pressing angle range corresponds to the desired pressing spindle motor angle.

[0132] Therefore, the given pressure angle range includes the pressing process and the lifting process, representing the spindle motor angle range from the control unit issuing the start pressing command to the control unit issuing the completion lifting command.

[0133] The desired pressure angle range refers to the desired angle range from when the pressure mechanism starts pressing down to when the spindle motor completes lifting.

[0134] The third step is to determine the presser foot stroke based on the fabric thickness and presser foot height. The program needs to preset the presser foot stroke corresponding to different fabric thicknesses and presser foot heights. Therefore, during execution, the presser foot stroke is determined based on the fabric thickness and presser foot height.

[0135] The stroke of the middle presser foot refers to the difference between the highest and lowest points of the middle presser foot during its movement. Correspondingly, the motor angles at the lowest and highest points of the middle presser foot need to be determined based on the fabric thickness and the height of the middle presser foot. Because the motor experiences overshoot during high-speed reciprocating oscillation, the presser foot actually reaches its highest point precisely at the start of the next downward press.

[0136] According to such Figure 4The curve shown indicates the commanded angle of the pressure foot motor. The actual angle is not equal to the given motor angle. The actual highest point angle is greater than the given highest point angle, and the actual lowest point angle is less than the given lowest point angle. Furthermore, the spindle angles corresponding to reaching the given lowest point angle and reaching the actual lowest point angle are different.

[0137] Therefore, it is possible to set:

[0138] Angle A represents the angle of the spindle motor when the control unit issues the command to start pressing down;

[0139] Angle B represents the angle of the spindle motor when the control unit issues the command to end the downward pressure.

[0140] Angle C represents the angle of the spindle motor when the control unit issues the start-lift command;

[0141] Angle D represents the angle of the spindle motor when the control unit issues the end lifting command;

[0142] Angle E represents the angle of the spindle motor when the middle pressure foot actually reaches its highest point;

[0143] Angle F represents the angle of the spindle motor when the middle pressure foot actually reaches its lowest point;

[0144] Angle G represents the spindle motor angle at which the middle pressure foot is expected to reach its highest point;

[0145] Angle H represents the spindle motor angle at which the middle pressure foot is expected to reach its lowest point;

[0146] Angle I represents the angle of the middle pressure foot motor at the highest point of the middle pressure foot, given by the control unit;

[0147] Angle J represents the angle of the middle pressure foot motor at the lowest point of the middle pressure foot, given by the control unit;

[0148] The advance angle K represents the spindle motor angle at which the desired middle pressure foot reaches its highest point, compared to the spindle motor angle at which the control unit issues the end-of-lift command. That is, advance angle K = angle G - angle D.

[0149] The advance angle L represents the spindle motor angle at which the desired middle pressure foot reaches its lowest point compared to the spindle motor angle at which the control unit issues the end-pressing command. That is, advance angle L = angle H - angle B.

[0150] During execution, the advance angle K and advance angle L differ depending on the speed setting. The higher the spindle speed, the greater this advance amount.

[0151] The fourth step is to control the presser foot motor and spindle motor based on the above information.

[0152] Specifically, this control method should also include the following specific control methods:

[0153] Adjust the synchronization, bottom dead center height, and follow-up stroke of the presser foot in the slow-down sewing area. Take the bag opening of a patch pocket machine as an example. The pocket opening is made by sewing multiple layers of folded fabric together. During the pressing process, the presser foot acts as a pressure point, compressing the fabric. As the needle moves downwards, pierces the fabric, and then leaves the fabric and returns to its highest point, the presser foot also completes the process of pressing down to contact the fabric, reaching its lowest point, and then lifting off the fabric to its highest point. During this process, if the needle has already pierced the fabric but the presser foot has not yet reached its lowest point, and the feeding mechanism is still feeding, problems such as fabric displacement, skipped stitches, broken threads, bent needles, or even broken needles can easily occur. In this case, by pressing down the presser foot earlier and setting a reasonable bottom dead center height and follow-up stroke, the fabric can be pressed into place in advance, and after feeding begins, the presser foot should be higher than the fabric to prevent fabric dragging.

[0154] During the sewing process, the control unit first reads the pattern information and determines that the sewing speed has significantly decreased in a certain section, while the presser foot height has significantly increased. This indicates that the fabric has been sewn into an area that is too thick. If only the sewing speed has decreased in the pattern, but the presser foot height has not changed, it cannot be determined that an area that is too thick has been sewn.

[0155] Then, when the thickness is determined to be too thick, the control program automatically advances angles A and B according to the preset reference parameters based on the sewing speed and the height of the middle presser foot. That is, by advancing the angle of the spindle motor that issues the start pressing command and the angle of the spindle motor that issues the end pressing command, the desired spindle motor angle (angle H) at the lowest point of the middle presser foot is advanced.

[0156] Next, adjust angles I and J according to the set center pressure foot height, and simultaneously increase the difference between angles J and I. That is, increase the center pressure foot height and increase the center pressure foot stroke. These adjustments are performed based on pre-set references to different center pressure foot heights and center pressure foot motor angles in the control program.

[0157] Finally, based on the above information, control the presser foot motor and the spindle motor.

[0158] The above judgment process is as follows: Figure 5 The technical solution provided in this application has the following characteristics:

[0159] 1. The mechanical structure is simple and straightforward, the motor load is light, and the process requirements are low;

[0160] 2. This allows the sewing machine to automatically adjust according to the fabric thickness and number of layers during the sewing process, thereby improving the quality of the sewing stitches;

[0161] This application provides a mechanical structure for the intermediate pressure foot, with upper and lower fisheye joints for connection; and a control method for the intermediate pressure foot, including a method for handling excessive thickness.

[0162] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A medium pressure foot mechanism, characterized in that, The drive structure is connected to the intermediate pressure foot through a crank-slider mechanism, enabling the intermediate pressure foot to complete a cyclic reciprocating motion and execute the target intermediate pressure foot stroke; The motion transmission component (8) at the top of the middle pressure foot passes through the top of the housing (14), and a sliding pair is formed between the motion transmission component (8) and the housing (14); the actuating component (11) at the bottom of the middle pressure foot passes through the bottom of the housing (14), and a sliding pair is formed between the actuating component (11) and the housing (14).

2. The pressure foot mechanism as described in claim 1, characterized in that, The crank-slider mechanism is equipped with a sensing plate and a matching sensor to obtain the extreme position of the pressure foot.

3. The pressure foot mechanism as described in claim 1, characterized in that, An adjustment device is provided on the middle pressure foot, so that the lower limit position of the middle pressure foot can be adjusted.

4. The pressure foot mechanism as described in claim 1, characterized in that, The drive structure includes a drive source (2), which is a motor.

5. The pressure foot mechanism as described in claim 1, characterized in that, The drive source (2) is mounted on the housing (14) via the support structure (1). One end of the drive crank (3) is connected to the output shaft of the drive source (2). The other end of the drive crank (3) is connected to the connector A (6) via fastener E (15). The connector A (6) is threadedly connected to one end of the motion transmission component (8) and locked by fastener A (7). The other end of the motion transmission component (8) is threadedly connected to the connector B (17) and locked by fastener D (18). Connector B (17) is connected to guide component (10) via fastener B (9) and fastener C (16); guide component (10) is set on actuator (11), actuator (11) moves up and down in auxiliary component (12), and working component (13) is fixed at the lower end of actuator (11).

6. The pressure foot mechanism as described in claim 1, characterized in that, The drive source (2) rotates clockwise, causing the drive crank (3) to rotate clockwise around the drive source (2) shaft; the drive crank (3) then causes the connecting part A (6) to lift, and transmits the motion to the motion transmission part (8), connecting part B (17), guide part (10), execution part (11), and working part (13) in sequence, causing the working part (13) to lift; The drive source (2) rotates counterclockwise, and the working part (13) descends; the drive source (2) swings back and forth, and when the working part (13) moves up and down at a certain amplitude, the working part (13) moves accordingly; the lower limit height and the following stroke are adjustable; when the sewing ends, the working part (13) is raised to the preset highest point, and when the working part (13) is raised to the highest point, the sensing element (5) is in the sensing area of ​​the detection feedback component (4).

7. The pressure foot mechanism as described in claim 1, characterized in that, Connector A (6) is a fisheye connector A, and connector B (17) is a fisheye connector B.

8. A pressure foot mechanism as described in claim 1, characterized in that, Fasteners A (7), B (9), E (15), and C (16) are threaded parts.

9. A sewing device, employing a presser foot mechanism as described in any one of claims 1-8, characterized in that, It includes a control unit, a spindle motor, a middle pressure foot motor, and a feeding motor. The control unit controls the rotation of the spindle motor, the middle pressure foot motor, and the feeding motor according to the target pattern parameters.

10. A sewing device as described in claim 9, characterized in that, The control unit is equipped with a display panel for setting the target parameters of the pattern.

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