Mechanism and method for adjusting pressure of presser foot and controlling presser foot lifting action and sewing machine

Abstract

The invention discloses a mechanism and method for adjusting presser foot pressure and controlling presser foot lifting action and a sewing machine. The mechanism comprises a stepping motor, and an output shaft of the stepping motor is fixedly sleeved with a presser foot lifting cam and a pressure adjusting gear; a presser foot lifting lever body rotating relative to a machine shell of the sewing machine is arranged on one side of the presser foot lifting cam, the upper end of the presser foot lifting lever body is rotationally connected with a presser foot lifting roller, the lower end of the presser foot lifting lever body is connected with a presser foot rod at the upper end of the presser foot through a transmission piece, and the presser foot lifting roller is used for abutting against the presser foot lifting cam rotating along with the output shaft in the presser foot height adjusting interval. The presser foot rod is driven to lift through the presser foot lifting lever body and the transmission piece; the pressure adjusting gear is meshed with a lead screw gear, the lead screw gear is fixedly arranged on a lead screw rotating relative to the machine shell in a sleeved mode, a liftable pressure adjusting sliding block is connected to the lead screw in a screwed mode, and a pressure adjusting spring is arranged between the lower end of the pressure adjusting sliding block and the upper end of the presser foot rod. According to the invention, the pressure of the presser foot can be adjusted and the presser foot lifting action can be controlled by using the same stepping motor.

Description

Technical Field

[0001] The invention belongs to the technical field of sewing machines, and in particular relates to a mechanism and method for adjusting presser foot pressure and controlling presser foot lifting action, as well as a sewing machine. Background Art

[0002] In the prior art, the presser foot pressure of a lockstitch sewing machine is mainly adjusted manually through a mechanical structure or through a stepping motor; and the presser foot lifting action of the lockstitch sewing machine can be controlled by an electromagnet or a stepping motor.

[0003] The existing implementation scheme for presser foot pressure adjustment has the following main problems: 1) When manually adjusting the presser foot pressure through a mechanical structure, the operation of manually adjusting the presser foot pressure is relatively complicated, and it is difficult to adjust the presser foot pressure during the sewing process; 2) When adjusting the presser foot pressure through a stepper motor, the stepper motor needs to maintain the presser foot pressure during the presser foot working process, so it needs to be kept powered on all the time, so the stepper motor is prone to heat up, which makes implementation difficult.

[0004] Moreover, in the existing flat-bed sewing machines, the stepper motor can only realize the function of adjusting the presser foot pressure or controlling the presser foot lifting action. The function of the stepper motor is relatively single and cannot realize the function of adjusting the presser foot pressure and controlling the presser foot lifting action at the same time. Therefore, the structure of the flat-bed sewing machine is relatively complex and the manufacturing cost is relatively high. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides a mechanism, method and sewing machine for adjusting the presser foot pressure and controlling the presser foot lifting action, which can use the same stepping motor to adjust the presser foot pressure and control the presser foot lifting action.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A mechanism for adjusting presser foot pressure and controlling presser foot lifting action comprises a stepping motor, wherein a presser foot lifting cam and a pressure adjusting gear are fixedly mounted on the output shaft of the stepping motor; a presser foot lifting lever body is provided on one side of the presser foot lifting cam and is rotated relative to the casing of the sewing machine; the upper end of the presser foot lifting lever body is rotatably connected to a presser foot lifting roller, and the lower end is connected to the presser foot rod at the upper end of the presser foot through a transmission member, and the presser foot lifting roller is used to abut against the presser foot lifting cam that rotates along with the output shaft in the presser foot height adjustment range, and drive the presser foot rod to rise and fall through the presser foot lifting lever body and the transmission member; the pressure adjusting gear is meshed with a lead screw gear, and the lead screw gear is fixedly mounted on a lead screw that rotates relative to the casing, and a pressure adjusting slider that can be raised and lowered is screwed on the lead screw, and a pressure adjusting spring is provided between the lower end of the pressure adjusting slider and the upper end of the presser foot rod.

[0008] Furthermore, the stepper motor includes a working interval and a non-working interval, the working interval includes a presser foot pressure adjustment interval and a presser foot height adjustment interval, and the presser foot pressure adjustment interval is between the presser foot height adjustment interval and the non-working interval; when the output shaft rotates in the presser foot pressure adjustment interval, the rotation angle of the output shaft is in the presser foot pressure adjustment interval, and in turn passes through the pressure adjustment gear, the lead screw gear and the lead screw, so that the pressure adjustment slider is lowered or raised relative to the lead screw to reduce or increase the length of the pressure regulating spring, and increases or decreases the pressure of the presser foot on the needle plate of the sewing machine through the presser foot rod; when the output shaft rotates in the presser foot height adjustment interval, the rotation angle of the output shaft is in the presser foot height adjustment interval, and in turn passes through the presser foot lifting cam, the presser foot lifting roller, the presser foot lifting lever body and the transmission part, so that the presser foot rod drives the presser foot to rise and lift or fall and fall to the sewing material on the top surface of the needle plate.

[0009] Furthermore, the transmission part includes a presser foot lifting plate and a presser foot guide frame, the lower end of the presser foot lifting lever body is hinged to the upper end of the presser foot lifting plate, and the lower part of the presser foot lifting plate is fixedly connected to the presser foot guide frame which is fixedly mounted on the upper part of the presser foot rod.

[0010] Furthermore, the pressure regulating slider is in sliding cooperation with a guide rail on the casing.

[0011] Furthermore, the axes of the lead screw and the presser foot rod coincide with each other, and the pressure-adjusting spring is sleeved on the lead screw.

[0012] Furthermore, a receiving channel with an open top end is provided in the middle portion of the presser foot rod, and the lower portion of the lead screw is inserted into the receiving channel from the top end opening of the receiving channel.

[0013] Furthermore, an avoidance hole is provided on the presser foot lifter lever body, and the output shaft of the stepper motor passes through the avoidance hole; the shell of the stepper motor is fixed on the casing and is located on one side of the presser foot lifter lever body, and the presser foot lifter cam and the pressure adjusting gear are both located on the other side of the presser foot lifter lever body and the pressure adjusting gear is arranged away from the presser foot lifter lever body.

[0014] A method for adjusting presser foot pressure and controlling presser foot lifting motion adopts the above-mentioned mechanism for adjusting presser foot pressure and controlling presser foot lifting motion, comprising the following steps:

[0015] S1. Determine whether it is necessary to adjust the pressure of the presser foot on the needle plate;

[0016] S2. When the presser foot pressure needs to be adjusted, the output shaft is controlled to rotate within the presser foot pressure adjustment range, so that the rotation angle of the output shaft is within the presser foot pressure adjustment range, the pressure adjusting gear rotates along with the output shaft, and drives the lead screw to rotate through the lead screw gear, and the pressure adjusting slider moves down or up relative to the lead screw to reduce or increase the length of the pressure adjusting spring, and increases or decreases the pressure of the presser foot on the needle plate through the presser foot rod, and records the rotation angle of the output shaft after the presser foot pressure is adjusted to the right position; when the presser foot pressure does not need to be adjusted, the rotation angle of the output shaft corresponding to the current presser foot pressure is directly recorded;

[0017] S3, controlling the output shaft to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure adjustment slider is raised and the compressive force on the pressure regulating spring is reduced, and the rotation angle of the output shaft transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft continues to rotate in the same direction, the presser foot lifting cam rotates along with the output shaft and abuts against the presser foot lifting roller, so as to gradually increase the pressure applied to the presser foot lifting roller, and in turn drives the presser foot rod to rise through the presser foot lifting lever body and the transmission member, and the presser foot rod drives the presser foot to rise and lift the presser foot;

[0018] S4, putting in the sewing material, controlling the rotation angle of the output shaft to return to the rotation angle recorded in step S2, so that the presser foot rod drives the presser foot to descend and reset, and starts sewing the sewing material.

[0019] Furthermore, the method further comprises the following steps:

[0020] S5, detecting whether the thickness of the sewing material changes;

[0021] S6. If the thickness of the sewing material changes, the output shaft is controlled to rotate in the presser foot pressure adjustment range to reduce or increase the pressure of the presser foot on the sewing material, and then the sewing of the sewing material is continued; if the thickness of the sewing material does not change, sewing is continued.

[0022] A sewing machine comprises a casing and a needle plate, and also comprises the above-mentioned mechanism for adjusting the pressure of the presser foot and controlling the action of lifting the presser foot.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action in the present invention includes a stepping motor, and a presser foot lifting cam and a pressure adjusting gear are fixedly mounted on the output shaft of the stepping motor; a presser foot lifting lever body that rotates relative to the casing of the sewing machine is provided on one side of the presser foot lifting cam, the upper end of the presser foot lifting lever body is rotatably connected to a presser foot lifting roller, and the lower end is connected to the presser foot rod at the upper end of the presser foot through a transmission member, the presser foot lifting roller is used to abut against the presser foot lifting cam that rotates along with the output shaft in the presser foot height adjustment range, and drive the presser foot rod to rise and fall through the presser foot lifting lever body and the transmission member; the pressure adjusting gear is engaged with the screw gear, and the screw gear is sleeved and fixed on the screw that rotates relative to the casing, a pressure adjusting slider that can be raised and lowered is screwed on the screw, and a pressure adjusting spring is provided between the lower end of the pressure adjusting slider and the upper end of the presser foot rod. In this way, when the presser foot pressure needs to be adjusted, the output shaft is controlled to rotate in the presser foot pressure adjustment range, and the rotation angle of the output shaft is in the presser foot pressure adjustment range, the pressure adjusting gear rotates along with the output shaft, and drives the screw to rotate through the screw gear, and the pressure adjusting slider drops or rises relative to the screw to reduce or increase the length of the pressure adjusting spring, and increase or decrease the pressure of the presser foot on the needle plate through the presser foot rod; when the presser foot needs to be lifted, the output shaft is controlled to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure adjusting slider rises and the compression force on the pressure adjusting spring is reduced. , thereby reducing the load required for the stepper motor to lift the presser foot, and the rotation angle of the output shaft transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft continues to rotate in the same direction, the presser foot lifting cam rotates along with the output shaft and abuts against the presser foot lifting roller to gradually increase the pressure applied to the presser foot lifting roller, and in turn drives the presser foot rod to rise through the presser foot lifting lever body and the transmission part, and the presser foot rod drives the presser foot to rise and lift the presser foot; in addition, if the thickness of the sewing material changes, the output shaft is controlled to rotate in the presser foot pressure adjustment range to reduce or increase the pressure of the presser foot on the sewing material. Therefore, this mechanism can use the same stepper motor to adjust the presser foot pressure and control the presser foot lifting action. The overall structure is compact, so that the sewing machine including the mechanism has a relatively simple structure and a relatively low manufacturing cost. The adjustment of the presser foot pressure and the control of the presser foot lifting action do not conflict with each other. The presser foot pressure can be adjusted in a static state, that is, before the sewing material is inserted, and the presser foot pressure can be adjusted in real time during the sewing process in combination with the thickness detection of the sewing material. At the same time, after the presser foot pressure adjustment is completed, the stepper motor is powered off and relies on the self-locking property of the lead screw and the pressure adjustment slider to maintain the current pressure of the presser foot. In this way, the stepper motor does not need to work continuously and is not easy to heat up. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the three-dimensional structure of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention when the presser foot is in a lowered state;

[0026] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure in another direction;

[0027] Figure 3 for Figure 1 A schematic diagram of a three-dimensional structure in another direction;

[0028] Figure 4 This is a schematic diagram of the three-dimensional structure of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention, with the pressure adjusting gear, screw gear, screw, pressure adjusting slider and pressure adjusting spring hidden, when the presser foot is in a lowered state;

[0029] Figure 5 This is a schematic diagram of the three-dimensional structure of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention, after the pressure adjusting gear, the lead screw gear, the lead screw, the pressure adjusting slider and the pressure adjusting spring are hidden, when the presser foot is in a raised state;

[0030] Figure 6 It is a schematic diagram of the three-dimensional structure of the presser foot in the lowered state of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention after the presser foot lifting cam, the presser foot lifting lever body, the presser foot lifting roller and the presser foot lifting plate are hidden;

[0031] Figure 7 A schematic diagram of the structure of the sliding fit between the pressure regulating slider and the guide rail on the cover;

[0032] Figure 8 This is a schematic diagram of the partitioning of the stepper motor;

[0033] Figure 9 A schematic side view of the structure of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention, with the pressure regulating gear and the presser foot lifting plate hidden, when the presser foot is in a lowered state;

[0034] Figure 10 A schematic side view of the structure of the mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action of the present invention, with the pressure regulating gear and the presser foot lifting plate hidden, when the presser foot is in a raised state;

[0035] Figure 11 The graph is a relationship between the output shaft rotation angle of the stepper motor and the presser foot pressure and height;

[0036] Figure 12 This is the control logic diagram of the present invention.

[0037] Explanation of the reference numerals in the figure: 1. stepper motor, 101. output shaft, 102. housing, 2. presser foot lifting cam, 3. presser foot lifting roller, 4. presser foot lifting lever body, 401. avoidance hole, 5. presser foot lifting plate, 6. presser foot guide, 7. pressure adjusting gear, 8. screw gear, 9. screw, 10. pressure adjusting slider, 11. pressure adjusting spring, 12. presser foot rod, 13. presser foot, 14. needle plate, 15. cover, 1501. guide rail. DETAILED DESCRIPTION

[0038] The following is a further detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, and are not intended to limit the present invention.

[0039] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0041] like Figures 1-6 、 Figure 9 and Figure 10 As shown, a mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action includes a stepping motor 1, on which the output shaft 101 of the stepping motor 1 is fixedly mounted a presser foot lifting cam 2 and a pressure adjusting gear 7; one side of the presser foot lifting cam 2 is provided with a presser foot lifting lever body 4 that rotates relative to the casing of the sewing machine, the upper end of the presser foot lifting lever body 4 is rotatably connected to a presser foot lifting roller 3 and the lower end is connected to the presser foot rod 12 at the upper end of the presser foot 13 through a transmission member, the presser foot lifting roller 3 is used to abut against the presser foot lifting cam 2 that rotates along with the output shaft 101 in the presser foot height adjustment range, and drives the presser foot rod 12 to rise and fall through the presser foot lifting lever body 4 and the transmission member; the pressure adjusting gear 7 is engaged with the screw gear 8, which is mounted and fixed on a screw 9 that rotates relative to the casing, and a pressure adjusting slider 10 that can be raised and lowered is screwed on the screw 9, and a pressure adjusting spring 11 is provided between the lower end of the pressure adjusting slider 10 and the upper end of the presser foot rod 12.

[0042] When the pressure of the presser foot 13 needs to be adjusted, the output shaft 101 is controlled to rotate in the presser foot pressure adjustment range, and the rotation angle of the output shaft 101 is in the presser foot pressure adjustment range, the pressure adjusting gear 7 rotates along with the output shaft 101, and drives the screw 9 to rotate through the screw gear 8, and the pressure adjusting slide block 10 drops or rises relative to the screw 9 to reduce or increase the length of the pressure regulating spring 11, and increase or decrease the pressure of the presser foot 13 on the needle plate 14 through the presser foot rod 12; when the presser foot 13 needs to be lifted, the output shaft 101 is controlled to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure regulating slide block 10 rises and reduces the pressure on the pressure regulating spring 11 The compression force is generated, thereby reducing the load required for the stepper motor 1 to lift the presser foot 13, and the rotation angle of the output shaft 101 transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft 101 continues to rotate in the same direction. The presser foot lifting cam 2 rotates along with the output shaft 101 and abuts against the presser foot lifting roller 3 to gradually increase the pressure applied to the presser foot lifting roller 3, and in turn drives the presser foot rod 12 to rise through the presser foot lifting lever body 4 and the transmission part, and the presser foot rod 12 drives the presser foot 13 to rise and lift the presser foot 13; in addition, if the thickness of the sewing material changes, the output shaft 101 is controlled to rotate in the presser foot pressure adjustment range to reduce or increase the pressure of the presser foot 13 on the sewing material.

[0043] Therefore, this mechanism can use the same stepper motor 1 to adjust the pressure of the presser foot 13 and control the action of lifting the presser foot 13. The overall structure is compact, so that the structure of the sewing machine including the mechanism is relatively simple and the manufacturing cost is relatively low. The adjustment of the pressure of the presser foot 13 and the control of the action of lifting the presser foot 13 do not conflict with each other. The pressure of the presser foot 13 can be adjusted in a static state, that is, before the sewing material is inserted, and the pressure of the presser foot 13 can be adjusted in real time during the sewing process in combination with the thickness detection of the sewing material. At the same time, after the pressure adjustment of the presser foot 13 is completed, the stepper motor 1 is powered off, and relies on the self-locking property of the screw 9 and the pressure adjustment slider 10 to maintain the current pressure of the presser foot 13. In this way, the stepper motor 1 does not need to work continuously and is not easy to heat up.

[0044] Among them, such as Figure 8As shown, the stepper motor 1 includes a working interval and a non-working interval, the working interval includes a presser foot pressure adjustment interval and a presser foot height adjustment interval, and the presser foot pressure adjustment interval is between the presser foot height adjustment interval and the non-working interval; when the output shaft 101 rotates in the presser foot pressure adjustment interval, the rotation angle of the output shaft 101 is in the presser foot pressure adjustment interval, and in turn through the pressure adjusting gear 7, the screw gear 8 and the screw 9, the pressure adjusting slider 10 is lowered or raised relative to the screw 9 to reduce or increase the length of the pressure adjusting spring 11, and through the presser foot rod 12 to increase or reduce the pressure of the presser foot 13 on the needle plate 14 of the sewing machine; when the output shaft 101 rotates in the presser foot height adjustment interval, the rotation angle of the output shaft 101 is in the presser foot height adjustment interval, and in turn through the presser foot lifting cam 2, the presser foot lifting roller 3, the presser foot lifting lever body 4 and the transmission parts, the presser foot rod 12 drives the presser foot 13 to rise and lift or fall and fall to the sewing material on the top surface of the needle plate 14.

[0045] The non-working interval is also called the blank interval. In the blank interval, the stepper motor 1 does not work, that is, the rotation angle of the output shaft 101 will not be in the blank interval, and the stepper motor 1 only needs to work in the presser foot pressure adjustment interval and the presser foot height adjustment interval.

[0046] In one embodiment, Figure 1-Figure 5 As shown, the transmission parts include a presser foot lifting plate 5 and a presser foot guide 6. The lower end of the presser foot lifting lever body 4 is hinged to the upper end of the presser foot lifting plate 5, and the lower part of the presser foot lifting plate 5 is fixedly connected to the presser foot guide 6 which is fixedly mounted on the upper part of the presser foot rod 12.

[0047] In this way, when the presser foot 13 needs to be lifted, the output shaft 101 is controlled to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure adjustment slider 10 rises and the compression force on the pressure adjusting spring 11 is reduced, thereby reducing the load required for the stepper motor 1 to lift the presser foot 13, and the rotation angle of the output shaft 101 transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft 101 continues to rotate in the same direction, the presser foot lifting cam 2 rotates along with the output shaft 101 and abuts against the presser foot lifting roller 3 to gradually increase the pressure applied to the presser foot lifting roller 3, and the presser foot lifting roller 3 drives the presser foot rod 12 to rise through the presser foot lifting lever body 4, the presser foot lifting plate 5 and the presser foot guide 6 in turn, and the presser foot rod 12 drives the presser foot 13 to rise and lift the presser foot 13.

[0048] In one embodiment, Figure 7 As shown, the pressure regulating slider 10 is slidably engaged with the guide rail 1501 on the housing, wherein the guide rail 1501 is provided on the housing cover 15. In this way, through the provision of the guide rail 1501, the pressure regulating slider 10 can stably rise or fall relative to the lead screw 9 during the rotation of the lead screw 9 relative to the housing.

[0049] In one embodiment,

[0050] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 6 、 Figure 7 、 Figure 9 and Figure 10 As shown, the axis of the lead screw 9 coincides with the axis of the pressure foot rod 12, and the pressure regulating spring 11 is sleeved on the lead screw 9. In this way, when the length of the pressure regulating spring 11 changes under the drive of the pressure regulating slider 10, the lead screw 9 can guide the pressure regulating spring 11.

[0051] Preferably, a receiving passage with a top opening is provided in the middle of the presser foot bar 12, and the lower part of the screw 9 is inserted into the receiving passage from the top opening of the receiving passage. In this way, the screw 9 can guide the presser foot bar 12 during the process of rising or falling.

[0052] In one embodiment, Figure 2 、 Figure 9 and Figure 10 As shown, a relief hole 401 is provided on the presser foot lift lever body 4, and the output shaft 101 of the stepper motor 1 passes through the relief hole 401; the housing 102 of the stepper motor 1 is fixed to the casing and is located on one side of the presser foot lift lever body 4, the presser foot lift cam 2 and the pressure adjustment gear 7 are both located on the other side of the presser foot lift lever body 4, and the pressure adjustment gear 7 is arranged away from the presser foot lift lever body 4. Figure 1-Figure 3 .

[0053] like Figure 12 As shown, a method for adjusting the presser foot pressure and controlling the presser foot lifting action adopts the above-mentioned mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action, comprising the following steps:

[0054] S1, determining whether it is necessary to adjust the pressure of the presser foot 13 on the needle plate 14;

[0055] S2. When the pressure of the presser foot 13 needs to be adjusted, the output shaft 101 is controlled to rotate within the presser foot pressure adjustment range, and the rotation angle of the output shaft 101 is within the presser foot pressure adjustment range. The pressure adjusting gear 7 rotates along with the output shaft 101, and drives the lead screw 9 to rotate through the lead screw gear 8, and the pressure adjusting slider 10 descends or rises relative to the lead screw 9 to reduce or increase the length of the pressure regulating spring 11, and increases or decreases the pressure of the presser foot 13 on the needle plate 14 through the presser foot rod 12, and records the rotation angle of the output shaft 101 after the pressure of the presser foot 13 is adjusted to the right position; when the pressure of the presser foot 13 does not need to be adjusted, the rotation angle of the output shaft 101 corresponding to the current pressure of the presser foot 13 is directly recorded;

[0056] S3, control the output shaft 101 to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure adjustment slider 10 rises and the compression force on the pressure-adjusting spring 11 is reduced, and the rotation angle of the output shaft 101 transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft 101 continues to rotate in the same direction, the presser foot lifting cam 2 rotates along with the output shaft 101 and abuts against the presser foot lifting roller 3, so as to gradually increase the pressure applied to the presser foot lifting roller 3, and make the presser foot lifting lever body 4 rotate relative to the casing, the presser foot lifting lever body 4 then drives the presser foot rod 12 to rise through the presser foot lifting plate 5 and the presser foot guide 6 in turn, and the presser foot rod 12 drives the presser foot 13 to rise and lift the presser foot 13;

[0057] S4, insert the sewing material, control the output shaft 101 to return to the angle recorded in step S2, so that the presser foot rod 12 drives the presser foot 13 to descend and reset, and start sewing the sewing material;

[0058] S5, detecting whether the thickness of the sewing material changes;

[0059] S6. If the thickness of the sewing material changes, the output shaft 101 is controlled to rotate in the presser foot pressure adjustment range to reduce or increase the pressure of the presser foot 13 on the sewing material, and then the sewing of the sewing material is continued; if the thickness of the sewing material does not change, sewing is continued.

[0060] In the present invention, Figure 11 1 is a graph showing the relationship between the rotation angle of the output shaft 101 of the stepping motor 1 and the pressure and height of the presser foot 13 .

[0061] A sewing machine comprises a casing and a needle plate 14, and also comprises the above-mentioned mechanism for adjusting the pressure of the presser foot and controlling the action of lifting the presser foot.

[0062] In summary, this mechanism can use the same stepper motor 1 to adjust the pressure of the presser foot 13 and control the action of lifting the presser foot 13. The overall structure is compact, so that the sewing machine structure including the mechanism is relatively simple and the manufacturing cost is relatively low. The adjustment of the pressure of the presser foot 13 and the control of the action of lifting the presser foot 13 do not conflict with each other. The pressure of the presser foot 13 can be adjusted in a static state, that is, before the sewing material is inserted, and the pressure of the presser foot 13 can be adjusted in real time during the sewing process in combination with the thickness detection of the sewing material. At the same time, after the pressure adjustment of the presser foot 13 is completed, the stepper motor 1 is powered off and relies on the self-locking property of the screw 9 and the pressure adjustment slider 10 to maintain the current pressure of the presser foot 13. In this way, the stepper motor 1 does not need to work continuously and is not easy to heat up.

[0063] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action, characterized in that: The invention comprises a stepper motor (1), wherein a presser foot lifting cam (2) and a pressure regulating gear (7) are fixedly mounted on the output shaft (101) of the stepper motor (1); a presser foot lifting lever body (4) which is rotatable relative to the housing of the sewing machine is provided on one side of the presser foot lifting cam (2); the upper end of the presser foot lifting lever body (4) is rotatably connected to a presser foot lifting roller (3) and the lower end is connected to a presser foot rod (12) at the upper end of a presser foot (13) through a transmission member; the presser foot lifting roller (3) is used to rotate with the output shaft (101) ) abuts against the presser foot lifting cam (2) rotating in the presser foot height adjustment range, and drives the presser foot rod (12) to rise and fall through the presser foot lifting lever body (4) and the transmission member; the pressure regulating gear (7) is engaged with the lead screw gear (8), and the lead screw gear (8) is fixed on the lead screw (9) rotating relative to the housing, and a pressure regulating slider (10) that can be raised and lowered is screwed on the lead screw (9), and a pressure regulating spring (11) is provided between the lower end of the pressure regulating slider (10) and the upper end of the presser foot rod (12).

2. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 1, characterized in that: The stepper motor (1) includes a working interval and a non-working interval, the working interval includes a presser foot pressure adjustment interval and a presser foot height adjustment interval, and the presser foot pressure adjustment interval is between the presser foot height adjustment interval and the non-working interval; when the output shaft (101) rotates in the presser foot pressure adjustment interval, the rotation angle of the output shaft (101) is in the presser foot pressure adjustment interval, and sequentially passes through the pressure adjustment gear (7), the lead screw gear (8) and the lead screw (9), so as to cause the pressure adjustment slider (10) to descend or ascend relative to the lead screw (9) to reduce or The length of the pressure regulating spring (11) is increased, and the pressure of the presser foot (13) on the needle plate (14) of the sewing machine is increased or decreased through the presser foot rod (12); when the output shaft (101) rotates in the presser foot height adjustment range, the rotation angle of the output shaft (101) is in the presser foot height adjustment range, and the presser foot rod (12) drives the presser foot (13) to rise and be lifted, or to fall and fall onto the sewing material on the top surface of the needle plate (14) through the presser foot lifting cam (2), the presser foot lifting roller (3), the presser foot lifting lever body (4) and the transmission member in sequence.

3. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 2, characterized in that: The transmission member comprises a presser foot lifting plate (5) and a presser foot guide frame (6); the lower end of the presser foot lifting lever body (4) is hinged to the upper end of the presser foot lifting plate (5); the lower part of the presser foot lifting plate (5) is fixedly connected to the presser foot guide frame (6) which is sleeved and fixed on the upper part of the presser foot rod (12).

4. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 2, characterized in that: The pressure regulating slider (10) is in sliding engagement with the guide rail (1501) on the casing.

5. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 2, characterized in that: The axes of the lead screw (9) and the pressure foot rod (12) coincide with each other, and the pressure regulating spring (11) is sleeved on the lead screw (9).

6. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 5, characterized in that: The middle part of the presser foot rod (12) is provided with an accommodating channel with a top opening, and the lower part of the lead screw (9) is inserted into the accommodating channel from the top opening of the accommodating channel.

7. The mechanism for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 2, characterized in that: The presser foot lifting lever body (4) is provided with an avoidance hole (401), and the output shaft (101) of the stepping motor (1) passes through the avoidance hole (401); the housing (102) of the stepping motor (1) is fixed on the casing and is located on one side of the presser foot lifting lever body (4); the presser foot lifting cam (2) and the pressure regulating gear (7) are both located on the other side of the presser foot lifting lever body (4), and the pressure regulating gear (7) is arranged away from the presser foot lifting lever body (4).

8. A method for adjusting presser foot pressure and controlling presser foot lifting, using the mechanism for adjusting presser foot pressure and controlling presser foot lifting as claimed in any one of claims 2 to 7, characterized in that: The following steps are involved: S1, determining whether it is necessary to adjust the pressure of the presser foot (13) on the needle plate (14); S2. When the pressure of the presser foot (13) needs to be adjusted, the output shaft (101) is controlled to rotate within the presser foot pressure adjustment range, and the rotation angle of the output shaft (101) is within the presser foot pressure adjustment range. The pressure adjustment gear (7) rotates along with the output shaft (101), and drives the lead screw (9) to rotate through the lead screw gear (8), and the pressure adjustment slider (10) descends or rises relative to the lead screw (9) to reduce or increase the length of the pressure adjustment spring (11), and increases or decreases the pressure of the presser foot (13) on the needle plate (14) through the presser foot rod (12), and records the rotation angle of the output shaft (101) after the pressure of the presser foot (13) is adjusted to the right position; when the pressure of the presser foot (13) does not need to be adjusted, the rotation angle of the output shaft (101) corresponding to the current pressure of the presser foot (13) is directly recorded; S3, controlling the output shaft (101) to rotate in one direction in the presser foot pressure adjustment range first, so that the pressure adjustment slider (10) rises and the compression force on the pressure adjustment spring (11) is reduced, and the rotation angle of the output shaft (101) transitions from the presser foot pressure adjustment range to the presser foot height adjustment range and the output shaft (101) continues to rotate in the same direction, the presser foot lifting cam (2) rotates along with the output shaft (101) and abuts against the presser foot lifting roller (3) to gradually increase the pressure applied to the presser foot lifting roller (3), and in turn drives the presser foot rod (12) to rise through the presser foot lifting lever body (4) and the transmission member, and the presser foot rod (12) drives the presser foot (13) to rise and lift the presser foot (13); S4, insert the sewing material, control the rotation angle of the output shaft (101) to return to the rotation angle recorded in step S2, so that the presser foot rod (12) drives the presser foot (13) to descend and reset, and start sewing the sewing material.

9. The method for adjusting the presser foot pressure and controlling the presser foot lifting action according to claim 8, characterized in that: The following steps are also included: S5, detecting whether the thickness of the sewing material changes; S6. If the thickness of the sewing material changes, the output shaft (101) is controlled to rotate in the presser foot pressure adjustment range to reduce or increase the pressure of the presser foot (13) on the sewing material, and then the sewing of the sewing material is continued; if the thickness of the sewing material does not change, sewing is continued.

10. A sewing machine, characterized in that: The invention comprises a casing and a needle plate (14), and also comprises a mechanism for adjusting the pressure of the presser foot and controlling the action of lifting the presser foot as claimed in any one of claims 1 to 7.

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