Stitch length adjusting and presser foot lifting device of sewing machine and sewing machine

Abstract

The utility model discloses a stitch length adjusting and presser foot lifting device of a sewing machine and the sewing machine, and relates to the technical field of sewing machines, in order to solve the problem that the presser foot lifting function and the stitch length adjusting function cannot be achieved at the same time, the device comprises a motor and a presser foot lifting assembly, and a stitch length adjusting assembly, a stitch length adjusting cam and a presser foot lifting cam are all arranged on a motor shaft; a needle pitch adjusting crank which is rotatably arranged on a motor shaft and connected with a connecting rod is hinged to the needle pitch adjusting cam, a cam pin is further arranged on the needle pitch adjusting cam, one end of a reset spring is fixed to the upper end of the connecting rod through a suspension screw, one end of the connecting rod is hinged to a swing plate base through a pin, and the swing plate base is limited through a buffering cushion on a machine shell. The positioning assembly comprises a driving source and a pressing plate, the boss is arranged on the inner cavity wall of the machine shell, the connecting rod is located between the pressing plate and the boss, the initial position of the driving shaft is in an extending state, and when the driving shaft retracts, the pressing plate is driven to press the connecting rod on the boss.

Description

Technical Field

[0001] The utility model relates to the technical field of sewing machines, and more particularly to a stitch length adjustment and presser foot lifting device for a sewing machine and the sewing machine. Background Art

[0002] A sewing machine uses one or more threads to create one or more stitches on fabric, interweaving or stitching one or more layers of fabric. It typically consists of a feed mechanism, a base, a transmission mechanism, and accessories. Through the coordinated movement of these mechanisms, the machine circulates and stitches the fabric together.

[0003] Currently, sewing machines utilize automatic presser foot lifters and automatic stitch length adjustment functions during the sewing process. A common method involves using an electromagnet to drive the presser foot lifter, while a stepper motor drives the stitch length adjustment mechanism. This drive method has the disadvantages of a complex structure and low transmission efficiency.

[0004] Sewing machines currently on the market use a single stepper motor to achieve both automatic presser foot lifting and automatic stitch length adjustment. A presser foot lifting cam and a stitch length adjustment cam are mounted on the stepper motor shaft. When the presser foot lifting cam is operating, the stitch length adjustment cam is in its inactive range, maintaining a constant stitch length. When the stitch length adjustment cam is operating, the presser foot lifting cam is in its inactive range, preventing the presser foot from automatically lifting. This design has the disadvantage of not being able to simultaneously drive both the presser foot lifting and stitch length adjustment components. Specifically, when the presser foot lifting cam is operating, the stitch length returns to a constant value due to the spring tension on the stitch length connecting rod, preventing adjustment to the desired stitch length. Furthermore, when the stitch length adjustment cam is operating, the presser foot cannot automatically lift.

[0005] Therefore, how to solve the problem that the presser foot lifting function and the needle length adjustment function cannot be realized at the same time is a problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0006] In view of this, the purpose of the present invention is to provide a stitch length adjustment and presser foot lifting device for a sewing machine, so that the presser foot lifting function and the stitch length adjustment function can be performed simultaneously on a sewing machine with a motor driving the presser foot lifting function and the stitch length adjustment function.

[0007] Another object of the present invention is to provide a sewing machine comprising the stitch length adjustment and presser foot lifting device of the above-mentioned sewing machine, so that the stitch length of the sewing machine can be kept constant at a set value during the sewing process, and the automatic presser foot lifting function can be activated at the same time.

[0008] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0009] A stitch length adjustment and presser foot lifting device for a sewing machine, comprising: a motor, a stitch length adjustment component, a presser foot lifting component and a positioning component;

[0010] The presser foot lifting assembly includes a presser foot lifting cam, and the stitch length adjustment assembly includes a stitch length adjustment cam, a connecting rod and a return spring. The stitch length adjustment cam and the presser foot lifting cam are both arranged on the motor shaft of the motor. The stitch length adjustment cam is hinged with a stitch length adjustment crank, the stitch length adjustment crank is rotatably arranged on the motor shaft and connected with the connecting rod. The stitch length adjustment cam is also provided with a cam pin. One end of the return spring is fixed to the upper end of the connecting rod by a suspension screw, and one end of the connecting rod is hinged to the swing plate seat by a pin. The swing plate seat is limited by a buffer pad on the casing, and the other end of the return spring is fixed to the lower end of the casing by a spring pin. When the motor rotates forward, the cam pin pushes the stitch length adjustment crank to rotate and causes the connecting rod to swing upward, and the presser foot lifting cam is separated from the presser foot lifting crank; when the motor rotates backward, the presser foot lifting cam abuts against one end of the presser foot lifting crank and causes the other end of the presser foot lifting crank to swing upward, and the cam pin is separated from the stitch length adjustment crank.

[0011] The positioning assembly includes a driving source, a pressure plate and a boss. The boss is arranged on the inner wall of the casing. The pressure plate is connected to the driving shaft of the driving source. The connecting rod is located between the pressure plate and the boss. The initial position of the driving shaft is extended. When the driving shaft contracts, the pressure plate is driven to press the connecting rod against the boss.

[0012] Preferably, an elastic retaining ring is provided on the needle distance adjusting cam, and the needle distance adjusting crank abuts against the needle distance adjusting cam through the elastic retaining ring.

[0013] Preferably, a positioning hole is provided in the middle of the swing plate seat, the swing plate seat is hinged to the bottom plate of the casing through the positioning hole, and one end of the connecting rod is hinged to the swing plate seat through a pin.

[0014] Preferably, a limiting plate is provided on the bottom plate, the limiting plate is fixed to the bottom plate through a support, a buffer pad is provided on the limiting plate for limiting the swing plate seat, and the buffer pad is fixed to the limiting plate through bolts and nuts.

[0015] Preferably, an electronic kneerest assembly is installed below the base plate.

[0016] Preferably, a roller is installed at one end of the presser foot lifting crank, and when the motor rotates reversely, the presser foot lifting cam abuts against the roller and causes the other end of the presser foot lifting crank to swing upward.

[0017] Preferably, the presser foot lifting assembly also includes a presser foot lifting push rod, one end of the presser foot lifting push rod is hinged to the presser foot lifting crank, and the other end of the presser foot lifting push rod is hinged to a presser foot lifting lever, and a knee-controlled lifting lever is installed on the presser foot lifting lever.

[0018] Preferably, one end of the knee-controlled lifting lever is connected to the presser foot lifting lever, the other end of the knee-controlled lifting lever is connected to one end of the knee-controlled lifting rod, the other end of the knee-controlled lifting rod is connected to the clamping rod guide frame, the clamping rod guide frame is connected to the clamping rod, and a presser foot is installed at the bottom of the clamping rod.

[0019] Preferably, a presser foot lifter crank bracket is fixed on the casing, and the middle part of the presser foot lifter crank is hinged on the presser foot lifter crank bracket.

[0020] A sewing machine comprises the stitch length adjustment and presser foot lifting device of any one of the above-mentioned sewing machines.

[0021] The stitch length adjustment and presser foot lifting device of a sewing machine provided by the utility model comprises a motor, a stitch length adjustment component, a presser foot lifting component and a positioning component. Specifically, the presser foot lifting component comprises a presser foot lifting cam, the stitch length adjustment component comprises a stitch length adjustment cam, a connecting rod and a return spring, the stitch length adjustment cam and the presser foot lifting cam are both arranged on the motor shaft of the motor, the stitch length adjustment cam and the presser foot lifting cam are driven to rotate by a motor, and the stitch length adjustment function and the presser foot lifting function are realized by a motor.

[0022] A stitch length adjusting crank is hinged on the stitch length adjusting cam, which is rotatably arranged on the motor shaft and connected to the connecting rod. A cam pin is also provided on the stitch length adjusting cam. One end of a return spring is fixed to the upper end of the connecting rod by a suspension screw, and the other end of the return spring is fixed to the lower end of the base plate by a spring pin. When the motor rotates forward, the cam pin pushes the stitch length adjusting crank to rotate and causes the connecting rod to swing upward, and the connecting rod drives the return spring to stretch, and the presser foot lifting cam is separated from the presser foot lifting crank; when the motor is reversed, the presser foot lifting cam abuts against one end of the presser foot lifting crank and causes the other end of the presser foot lifting crank to swing upward, and the cam pin is separated from the stitch length adjusting crank. At the same time, the connecting rod is under the action of the return spring. When the lever is pulled down to its initial position, one end of the connecting rod is hinged to the swing plate seat by a pin, and the swing plate seat is limited by the buffer pad on the casing, and the swing plate seat is limited by the buffer pad at this time; that is to say, in the circular motion direction of the motor shaft, the needle distance adjusting cam has a working interval and a non-working interval, and the presser foot lifting cam has a working interval and a non-working interval, and when the needle distance adjusting cam is in the working interval, the presser foot lifting cam is in the non-working interval, and when the presser foot lifting cam is in the working interval, the needle distance adjusting cam is in the non-working interval, and while the needle distance adjusting function and the presser foot lifting function are realized by one motor, the needle distance adjusting assembly and the presser foot lifting assembly work independently of each other without interfering with each other.

[0023] The positioning assembly includes a driving source, a pressure plate and a boss. The boss is arranged on the inner cavity wall of the casing. The pressure plate is connected to the driving shaft of the driving source. The pressure plate is driven to move synchronously by the telescopic movement of the driving shaft. The connecting rod is located between the pressure plate and the boss to ensure that the connecting rod can move up and down without interfering with the pressure plate and the boss. The initial position of the driving shaft is extended. When the driving shaft contracts, the pressure plate is driven to press the connecting rod against the boss. After the needle distance adjustment cam rotates to set the needle distance, when the driving source is started, the driving shaft contracts in the direction of the driving source, driving the pressure plate to move in the same direction, clamping the connecting rod between the pressure plate and the boss. At this time, the pressure plate will A certain pressure is applied to the connecting rod so that the connecting rod is fixed at the position of the set stitch length. When the stitch length adjustment cam rotates forward to disengage the cam pin and the stitch length adjustment crank, the downward force of the return spring acting on the connecting rod and the reverse pressing friction force of the pressure plate on the connecting rod offset each other, and the connecting rod will remain in the original set position unchanged, thereby keeping the stitch length at the set value. At this time, the motor shaft rotates forward, so that the presser foot lifting cam drives the presser foot to automatically lift, and the stitch length remains unchanged at the set value; when the drive source is turned off, the pressure plate is reset, the connecting rod is released, and the connecting rod moves accordingly under the pull of the return spring and the action of the stitch length adjustment crank.

[0024] Compared with the existing technology, the advantage of the present application is that by adding a driving source, a motor can be used to drive the presser foot lifting function and the stitch length adjustment function of the sewing machine. The presser foot lifting function and the stitch length adjustment function can work at the same time, so that the sewing machine can keep the stitch length at the set value during the sewing process and start the automatic presser foot lifting function at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 This is a structural diagram of the stitch length adjustment and presser foot lifting device of the sewing machine provided by the utility model;

[0027] Figure 2 This is a schematic diagram of the interior of the stitch length adjustment and presser foot lifting device of the sewing machine provided by the present invention;

[0028] Figure 3 A partial enlarged view of the stitch length adjustment and presser foot lifting device of the sewing machine provided by the present invention;

[0029] Figure 4 This is a structural diagram of the needle distance adjustment assembly provided by the utility model;

[0030] Figure 5 A schematic diagram of the structure of the housing provided by the utility model;

[0031] Figure 6 This is a partial cross-sectional view of the needle distance adjustment assembly provided by the present invention when adjusting the needle distance;

[0032] Figure 7 This is a schematic diagram of the force acting on the connecting rod of the needle distance adjustment assembly provided by the present invention;

[0033] Figure 8 This is a bottom schematic diagram of the stitch length adjustment and presser foot lifting device of the sewing machine provided by the utility model.

[0034] Reference numerals:

[0035] 1-motor, 11-motor shaft;

[0036] 2-stitch adjustment assembly, 21-stitch adjustment cam, 22-connecting rod, 23-return spring, 24-stitch adjustment crank, 25-cam pin, 26-screw, 27-spring pin, 28-swing plate seat, 281-positioning hole, 29-pin;

[0037] 3-presser foot lifting assembly, 31-presser foot lifting cam, 32-presser foot lifting crank, 33-presser foot lifting push rod, 34-presser foot lifting lever, 35-knee control lifting lever 1, 36-knee control lifting rod, 37-presser foot;

[0038] 4-positioning assembly, 41-driving source, 411-driving shaft, 42-pressing plate, 43-boss;

[0039] 5- housing, 51- bottom plate;

[0040] 6- elastic retaining ring;

[0041] 7-limiting plate;

[0042] 8-pillar;

[0043] 9-Cushion. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection 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 this utility model based on specific circumstances.

[0046] It should be noted that the directional words such as "upper" and "lower" below are defined based on the drawings in the specification.

[0047] The core of the present invention is to provide a stitch length adjustment and presser foot lifting device for a sewing machine, which enables the presser foot lifting and stitch length adjustment functions to be performed simultaneously on a sewing machine in which a single motor (1) drives both the presser foot lifting and stitch length adjustment functions. Another core of the present invention is to provide a sewing machine including the stitch length adjustment and presser foot lifting device, which enables the sewing machine to maintain the stitch length at a set value during the sewing process while activating the automatic presser foot lifting function.

[0048] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 A stitch length adjustment and presser foot lifting device for a sewing machine includes a motor 1, a stitch length adjustment component 2, a presser foot lifting component 3 and a positioning component 4.

[0049] Specifically, the presser foot lifting assembly 3 includes a presser foot lifting cam 31, and the stitch length adjustment assembly 2 includes a stitch length adjustment cam 21, a connecting rod 22 and a return spring 23. The stitch length adjustment cam 21 and the presser foot lifting cam 31 are both arranged on the motor shaft 11 of the motor 1. The stitch length adjustment cam 21 and the presser foot lifting cam 31 are driven to rotate by a motor 1, and the stitch length adjustment function and the presser foot lifting function are realized by a motor 1.

[0050] A stitch length adjusting crank 24 is hinged on the stitch length adjusting cam 21, and the stitch length adjusting crank 24 is rotatably arranged on the motor shaft 11 and connected to the connecting rod 22. A cam pin 25 is also provided on the stitch length adjusting cam 21, and one end of the return spring 23 is fixed to the upper end of the connecting rod 22 by a suspension screw 26, and the other end of the return spring 23 is fixed to the lower end of the casing 5 by a spring pin 27. When the motor 1 rotates forward, the cam pin 25 pushes the stitch length adjusting crank 24 to rotate and causes the connecting rod 22 to swing upward, and the connecting rod 22 drives the return spring 23 to stretch, and the presser foot lifting cam 31 is separated from the presser foot lifting crank 32; when the motor 1 is reversed, the presser foot lifting cam 31 abuts against one end of the presser foot lifting crank 32 and causes the other end of the presser foot lifting crank 32 to swing upward, and the cam pin 25 and the stitch length adjusting crank 24 are separated, and at the same time, the connecting rod 22 is pulled to the initial position under the action of the return spring 23, and one end of the connecting rod 22 is hinged to the swing plate seat 28 by a pin 29, and the swing plate seat 28 is limited by the buffer pad 9 on the casing 5; that is to say, in the circumferential motion direction of the motor shaft 11, the needle distance adjusting cam 21 has a working interval and a non-working interval, and the presser foot lifting cam 31 has a working interval and a non-working interval, and when the needle distance adjusting cam 21 is in the working interval, the presser foot lifting cam 31 is in the non-working interval, and when the presser foot lifting cam 31 is in the working interval, the needle distance adjusting cam 21 is in the non-working interval, and while the needle distance adjusting function and the presser foot lifting function are realized by one motor 1, the needle distance adjusting component and the presser foot lifting component 3 work independently of each other without interfering with each other.

[0051] The positioning assembly 4 includes a driving source 41, a pressure plate 42 and a boss 43. The boss 43 is arranged on the inner cavity wall of the casing 5. The pressure plate 42 is connected to the driving shaft 411 of the driving source 41. The telescopic movement of the driving shaft 411 drives the pressure plate 42 to move synchronously. The connecting rod 22 is located between the pressure plate 42 and the boss 43 to ensure that the connecting rod 22 can move up and down without interfering with the pressure plate 42 and the boss 43. The initial position of the driving shaft 411 is an extended state. When the driving shaft 411 contracts, it drives the pressure plate 42 to press the connecting rod 22 on the boss 43. After the needle distance adjusting cam 21 rotates to set the needle distance, when the driving source 41 is started, the driving shaft 411 contracts toward the driving source 41, driving the pressure plate 42 to move in the same direction, clamping the connecting rod 22 between the pressure plate 42 and When the drive source 41 is turned off, the pressure plate 42 is reset, and the connecting rod 22 is released. The connecting rod 22 moves accordingly under the action of the pulling force of the return spring 23 and the needle distance adjustment crank 24.

[0052] In this stitch length adjustment and presser foot lifting device, the motor 1 can be a stepper motor, mounted on the housing 5. When the motor 1 rotates forward, it drives the stitch length adjustment cam 21 to rotate, and pushes the stitch length adjustment crank 24 to rotate via the cam pin 25, thereby pulling the other stitch length adjustment components to rotate via the connecting rod 22, thereby achieving stitch length adjustment and reverse stitching functions. At this time, the presser foot lifting cam 31 is separated from the presser foot lifting crank 32. When the motor 1 rotates backward, it drives the presser foot lifting cam 31 to rotate, and the presser foot lifting cam 31 abuts against one end of the presser foot lifting crank 32, causing the other end of the presser foot lifting crank 32 to swing upward, thereby driving the other presser foot lifting components to rotate, achieving the presser foot lifting function. At this time, the cam pin 25 is separated from the stitch length adjustment crank 24. While realizing the stitch length adjustment and presser foot lifting functions through one motor 1, the separation of the two structures is realized (when adjusting the stitch length, the presser foot lifting cam 31 rotates forward with the motor 1 but does not contact the presser foot lifting crank 32, so it does not affect the presser foot lifting structure; similarly, when lifting the presser foot 37, the stitch length adjustment cam 21 rotates reversely with the motor 1 but the cam pin 25 does not contact the stitch length adjustment crank 24, so it does not affect the stitch length adjustment structure, that is, the mechanical structures realizing the two functions are separable and do not affect each other), the parts are not easy to wear, the assembly requirements are low, when a single structure fails, the other structure can still be used normally, and only a single structure needs to be adjusted during maintenance.

[0053] A driving source 41 is arranged near the connecting rod 22 for adjusting the needle pitch. The driving source 41 can be an electromagnet or a cylinder, or other driving device. The driving source 41 is provided with a driving shaft 411. The driving shaft 411 can perform telescopic movement under the action of the driving source 41. A pressure plate 42 is provided at the other end of the driving shaft 411. The pressure plate 42 is fixed to the driving shaft 411 by a pin 29. A boss 43 is provided near the connecting rod 22 in the inner cavity of the casing 5. The connecting rod 22 is located between the boss 43 and the pressure plate 42 during the entire working process, and maintains a certain distance from both of them to ensure that the connecting rod 22 can move up and down without interfering with each other.

[0054] The stitch length adjustment and presser foot lifting device of the sewing machine set up in the above manner can be realized by adding a driving source 41, so that a motor 1 drives the presser foot lifting function and the stitch length adjustment function of the sewing machine. The presser foot lifting function and the stitch length adjustment function can work simultaneously, so that the sewing machine can keep the stitch length unchanged at the set value during the sewing process, and the automatic presser foot lifting function can be started at the same time.

[0055] Please refer to Figure 3 、 Figure 4 and Figure 6 An elastic circlip 6 is provided on the needle distance adjusting cam 21 , and the needle distance adjusting crank 24 abuts against the needle distance adjusting cam 21 through the elastic circlip 6 .

[0056] It should be noted that the needle distance adjusting crank 24 is mounted on the needle distance adjusting cam 21 , and the elastic retaining ring 6 abuts against one side of the needle distance adjusting crank 24 to limit the position thereof.

[0057] Please refer to Figure 4 and Figure 8 The needle distance adjustment assembly 2 also includes a swing plate seat 28, a positioning hole 281 is provided in the middle of the swing plate seat 28, the swing plate seat 28 is hinged to the bottom plate 51 of the casing 5 through the positioning hole 281, and one end of the connecting rod 22 is hinged to the swing plate seat 28 through a pin 29.

[0058] It can be understood that when the motor 1 rotates forward, it will drive the needle distance adjustment cam 21 to rotate, and push the needle distance adjustment crank 24 to rotate through the cam pin 25, thereby pulling the swing plate seat 28 to rotate through the connecting rod 22, changing the relative angle between the swing plate seat 28 and the bottom plate 51 of the casing 5, and realizing the needle distance adjustment and reverse sewing functions.

[0059] A presser foot lifting cam 31 and a stitch length adjusting cam 21 are provided on the stepping motor shaft 11, and a stitch length adjusting crank 24 is provided on the stitch length adjusting cam 21. The stitch length adjusting crank 24 is clamped on the stitch length adjusting cam 21 through an elastic retaining ring 6 of the shaft, and the stitch length adjusting crank 24 can rotate around the stepping motor shaft 11; a cam pin 25 is provided on the stitch length adjusting cam 21, and when the stitch length adjusting cam 21 rotates counterclockwise, the stitch length adjusting crank 24 is driven to rotate in the same direction through the cam pin 25. The connecting rod 22 is hinged at the other end of the needle pitch adjusting crank 24, and the other end of the connecting rod 22 is hinged to the swing plate seat 28 through a pin 29. The swing plate seat 28 is fixed to the bottom plate 51 of the casing 5 through the middle positioning hole 281, and the swing plate seat 28 can rotate around the positioning hole 281; a suspension screw 26 is provided on the connecting rod 22 for fixing the reset spring 23, and the lower end of the reset spring 23 is fixed to the lower end position of the casing 5 by a spring pin 27.

[0060] Furthermore, a limiting plate 7 is provided on the bottom plate 51 , and the limiting plate 7 is fixed to the bottom plate 51 through a support 8 . A buffer pad 9 for limiting the swing plate seat 28 is provided on the limiting plate 7 , and the buffer pad 9 is fixed to the limiting plate 7 through bolts and nuts.

[0061] It should be noted that the limit plate 7 is fixed to the base plate 51 via a support 8. A bolt is connected to the limit plate 7. A buffer pad 9 is provided at one end of the bolt and is tightened by a nut at the other end. The buffer pad 9 is mounted on the limit plate 7 via the bolt, and the height of the buffer pad 9 is adjustable. When the swing plate seat 28 is able to abut against the buffer pad 9, its rotation angle is maximum. When adjusting the stitch length, the height of the buffer pad 9 is adjusted by rotating the bolt to limit the maximum rotation angle of the swing plate seat 28, thereby achieving the limit function for the maximum stitch length. When the presser foot 37 is raised, the motor 1 reverses and no longer applies force to the swing plate seat 28. Only the reset spring 23 applies force to it, pulling it back to achieve the reset function. The structure composed of the limit plate 7 and the buffer pad 9 can prevent the swing plate seat 28 from moving when resetting, thereby achieving the limit function for the swing plate seat 28.

[0062] When the stitch length adjustment assembly 2 is working, the stitch length adjustment cam 21 is driven to rotate counterclockwise by the stepping motor shaft 11, and the cam pin 25 drives the stitch length adjustment crank 24 to rotate in the same direction. The stitch length adjustment crank 24 pulls up the connecting rod 22 and drives the swing plate seat 28 to rotate, thereby realizing the adjustment of the stitch length; when the stitch length adjustment cam 21 rotates in the opposite direction, the cam pin 25 disengages from the stitch length adjustment crank 24. At this time, the connecting rod 22 will move downward under the pulling force of the return spring 23, causing the stitch length adjustment crank 24 to also rotate in the opposite direction, thereby realizing the two-way adjustment function of the stitch length.

[0063] When the stitch length adjustment component 2 adjusts the stitch length into place, the control drive source 41 is started, so that the drive shaft 411 contracts toward the drive source 41, driving the pressure plate 42 to move in the same direction, clamping the connecting rod 22 between the pressure plate 42 and the boss 43. At this time, the pressure plate 42 will exert a certain pressure on the connecting rod 22, so that the connecting rod 22 is fixed at the position of the set stitch length. When the stitch length adjustment cam 21 rotates forward to disengage the cam pin 25 and the stitch length adjustment crank 24, the connecting rod 22 moves downward under the pulling force of the return spring 23, so that the swing plate seat 28 can abut against the buffer pad 9, thereby maintaining the stitch length at a constant value when the stitch length adjustment cam 21 is not working (that is, the presser foot lifting cam 31 is working).

[0064] In the above embodiment, the electronic kneerest assembly is installed below the bottom plate 51 .

[0065] It can be understood that the electronic knee rest assembly is installed under the base plate 51, and can output an electrical signal according to the displacement of the user's knee after leaning against the device, and combine with the electronic control to control the height of the presser foot 37. The greater the displacement, the higher the height of the presser foot 37. When in use, it is only necessary to overcome the spring force of the return spring in the electronic knee rest assembly, which is much smaller than the traditional mechanical knee rest force, so as to achieve a lighter knee rest force to lift the presser foot 37.

[0066] Please refer to Figure 2One end of the presser foot lifting crank 32 is installed with a roller. When the motor 1 rotates reversely, the presser foot lifting cam 31 abuts against the roller and causes the other end of the presser foot lifting crank 32 to swing upward.

[0067] It should be noted that the presser foot lifting crank 32 contacts the presser foot lifting cam 31 through the roller. When the presser foot lifting cam 31 contacts the roller and presses the roller downward, the roller rotates. This structure can better transmit the power, and the presser foot lifting crank 32 and the presser foot lifting cam 31 are not easy to wear.

[0068] On the basis of the above embodiment, the presser foot lifting assembly 3 also includes a presser foot lifting rod 33, one end of the presser foot lifting rod 33 is hinged to the presser foot lifting crank 32, and the other end of the presser foot lifting rod 33 is hinged to a presser foot lifting lever 34, and a knee-controlled lifting lever 35 is installed on the presser foot lifting lever 34.

[0069] It is understood that a roller is mounted on one end of the presser foot lift crank 32, and a presser foot lifter rod 33 is hingedly connected to the other end of the presser foot lift crank 32. The other end of the presser foot lifter rod 33 is hingedly connected to a presser foot lift lever 34, which is in turn mounted on a knee-operated lift lever. When the motor 1 rotates in reverse, it drives the presser foot lift cam 31 to rotate. The presser foot lift cam 31 presses down on the roller on one end of the presser foot lift crank 32, causing the other end of the presser foot lift crank 32 to move upward. The presser foot lift crank 32 automatically rotates the presser foot lift rod 33, which in turn drives the automatic presser foot lift lever 34 to rotate, thereby rotating the knee-operated lift lever 35, thus achieving the presser foot lift function.

[0070] In the above embodiment, one end of the knee-controlled lifting lever 35 is connected to the presser foot lifting lever 34, the other end of the knee-controlled lifting lever 35 is connected to one end of the knee-controlled lifting rod 36, the other end of the knee-controlled lifting rod 36 is connected to the clamping rod guide frame, the clamping rod guide frame is connected to the clamping rod, and a presser foot 37 is installed at the bottom of the clamping rod.

[0071] It should be noted that when the knee-operated lifting lever 35 rotates, the presser foot lifting lever 34 drives the pressing rod guide to rotate, and the pressing rod guide causes the pressing rod to move up and down, realizing the presser foot lifting function. The height of the presser foot lifting 37 can be precisely adjusted by the rotation angle of the presser foot lifting cam 31.

[0072] In the above situation, a presser foot lifting crank bracket is fixed on the housing 5, and the middle portion of the presser foot lifting crank 32 is hinged on the presser foot lifting crank bracket.

[0073] It can be understood that the presser foot lifting crank bracket is fixed on the casing 5, and the presser foot lifting crank 32 is hinged on the presser foot lifting crank bracket through the presser foot lifting 37 driving the crank pin.

[0074] In summary, the stitch length adjustment and presser foot lifting device of the sewing machine provided by the present invention is that after the stitch length adjustment cam 21 rotates to set the stitch length, the drive source 41 is started, the drive shaft 411 contracts toward the drive source 41, and drives the pressure plate 42 to move in the same direction, clamping the connecting rod 22 between the pressure plate 42 and the boss 43. At this time, the pressure plate 42 will apply a certain pressure to the connecting rod 22. When the stitch length adjustment cam 21 rotates in the opposite direction to disengage the cam pin 25 and the stitch length adjustment crank 24, the downward pulling force of the return spring 23 on the connecting rod 22 is offset by the reverse pressing friction force generated by the pressure of the pressure plate 42, and the connecting rod 22 will remain in the original set position unchanged, thereby maintaining the stitch length at the set value. At this time, the stepping motor shaft 11 rotates in the forward direction, causing the presser foot lifting cam 31 to drive the presser foot 37 to automatically lift, and the stitch length remains unchanged at the set value. When the driving source 41 is turned off, the pressing plate 42 is reset and the connecting rod 22 is released. The connecting rod 22 moves accordingly under the pulling force of the reset spring 23 and the action of the needle distance adjusting crank 24.

[0075] By adding a driving source 41, it is achieved that on a sewing machine with a stepping motor driving the presser foot lifting function and the stitch length adjustment function, the presser foot lifting function and the stitch length adjustment function can work simultaneously, avoiding the disadvantage that similar structures cannot work simultaneously; the sewing machine can keep the stitch length at a set value during the sewing process, and the automatic presser foot lifting function can be started at the same time; when the fabric suddenly becomes extremely thick during the sewing process and the normal presser foot 37 cannot pass through, the automatic presser foot lifting function is started to lift the presser foot 37 to a certain height, allowing the extremely thick fabric to pass smoothly, and then return to the normal presser foot 37 state after passing the seam for normal sewing, thereby achieving effective sewing and ensuring that the stitch length of the entire stitch is consistent; the presser foot 37 can be automatically lifted during the sewing process without changing the stitch length value.

[0076] In addition to the stitch length adjustment and presser foot lifting device of the sewing machine disclosed in the above-mentioned embodiments, the present invention also provides a sewing machine including the stitch length adjustment and presser foot lifting device of the above-mentioned sewing machine. For the structures of other parts of the sewing machine, please refer to the prior art and will not be described in detail herein.

[0077] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0078] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0079] The above is a detailed introduction to the stitch length adjustment and presser foot lifting device of a sewing machine and the sewing machine provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core concept of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A sewing machine needle length adjustment and presser foot lifting device, characterized in that: include: Motor (1), stitch length adjustment assembly (2), presser foot lift assembly (3) and positioning assembly (4); The presser foot lifting assembly (3) includes a presser foot lifting cam (31), and the stitch length adjustment assembly (2) includes a stitch length adjustment cam (21), a connecting rod (22) and a return spring (23). The stitch length adjustment cam (21) and the presser foot lifting cam (31) are both arranged on the motor shaft (11) of the motor (1). A stitch length adjustment crank (24) is hinged on the stitch length adjustment cam (21). The stitch length adjustment crank (24) is rotatably arranged on the motor shaft (11) and connected to the connecting rod (22). A cam pin (25) is also provided on the stitch length adjustment cam (21). The return spring (23) One end of the return spring (23) is fixed to the upper end of the connecting rod (22) by a suspension screw (26), one end of the connecting rod (22) is hinged to the swing plate seat (28) by a pin (29), the swing plate seat (28) is limited by a buffer pad (9) on the housing (5), and the other end of the return spring (23) is fixed to the lower end of the housing (5) by a spring pin (27). When the motor (1) rotates forward, the cam pin (25) pushes the needle distance adjustment crank (24) to rotate and causes the connecting rod (22) to swing upward, and the presser foot lifting cam (31) is separated from the presser foot lifting crank (32); When the motor (1) rotates in the reverse direction, the presser foot lifting cam (31) abuts against one end of the presser foot lifting crank (32) and causes the other end of the presser foot lifting crank (32) to swing upward, and the cam pin (25) separates from the stitch length adjusting crank (24); The positioning assembly (4) includes a driving source (41), a pressure plate (42) and a boss (43), wherein the boss (43) is provided on the inner wall of the housing (5), the pressure plate (42) is connected to the driving shaft (411) of the driving source (41), the connecting rod (22) is located between the pressure plate (42) and the boss (43), and the driving shaft (411) is initially in an extended state. When the driving shaft (411) contracts, it drives the pressure plate (42) to press the connecting rod (22) against the boss (43).

2. The stitch length adjustment and presser foot lifting device of a sewing machine according to claim 1, characterized in that: An elastic retaining ring (6) is provided on the needle distance adjusting cam (21), and the needle distance adjusting crank (24) abuts against the needle distance adjusting cam (21) via the elastic retaining ring (6).

3. The stitch length adjustment and presser foot lifting device of a sewing machine according to claim 1, characterized in that: A positioning hole (281) is provided in the middle of the swing plate seat (28), and the swing plate seat (28) is hinged to the bottom plate (51) of the housing (5) through the positioning hole (281).

4. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 3, characterized in that: A limiting plate (7) is provided on the bottom plate (51), and the limiting plate (7) is fixed to the bottom plate (51) via a support (8). The limiting plate (7) is provided with a buffer pad (9) for limiting the swing plate seat (28), and the buffer pad (9) is fixed to the limiting plate (7) via bolts and nuts.

5. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 4, characterized in that: An electronic kneerest assembly is installed below the bottom plate (51).

6. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 1, characterized in that: A roller is mounted on one end of the presser foot lifting crank (32). When the motor (1) rotates in reverse, the presser foot lifting cam (31) abuts against the roller and causes the other end of the presser foot lifting crank (32) to swing upward.

7. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 6, characterized in that: The presser foot lifting assembly (3) further comprises a presser foot lifting push rod (33), one end of which is hinged to the presser foot lifting crank (32), and the other end of which is hinged to a presser foot lifting lever (34), and a knee-controlled lifting lever (35) is mounted on the presser foot lifting lever (34).

8. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 7, characterized in that: One end of the knee-controlled lifting lever (35) is connected to the presser foot lifting lever (34), the other end of the knee-controlled lifting lever (35) is connected to one end of the knee-controlled lifting rod (36), the other end of the knee-controlled lifting rod (36) is connected to the pressing rod guide frame, the pressing rod guide frame is connected to the pressing rod, and a presser foot (37) is installed at the bottom of the pressing rod.

9. The stitch length adjustment and presser foot lifting device for a sewing machine according to claim 8, characterized in that: A presser foot lift crank bracket is fixed to the housing (5), and the middle portion of the presser foot lift crank (32) is hinged to the presser foot lift crank bracket.

10. A sewing machine, characterized in that: The invention comprises the stitch length adjustment and presser foot lifting device of a sewing machine according to any one of claims 1 to 9.

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