Sewing machine and sewing machine control method

Abstract

This invention discloses a sewing machine and a sewing machine control method, relating to the field of sewing equipment. The sewing machine includes a base, a needle plate, a rotary hook, and a shifting mechanism. The needle plate and rotary hook are mounted on the base, with the rotary hook positioned below the needle plate. The needle plate has needle holes extending vertically. The shifting mechanism includes a motor, a planar four-bar linkage, and a shift lever. The planar four-bar linkage is mounted on the base. The motor is connected to the shift lever via the planar four-bar linkage. In reverse sewing, the motor drives the shift lever before the needle enters the sewing position, causing the end of the shift lever away from the planar four-bar linkage to move circumferentially around the axis of the needle hole, thus shifting the portion of the bobbin thread between the needle plate and the rotary hook to cross the axis of the needle hole. The sewing machine provided by this invention can form a forward stitch in reverse sewing and features a simpler, more compact structure and lower cost.

Description

Technical Field

[0001] This invention relates to the field of sewing equipment, and more specifically, to a sewing machine and a sewing machine control method. Background Technology

[0002] There are two types of sewing operations using a sewing machine: forward sewing and reverse sewing. In forward sewing, the bobbin thread and the fabric thread are on the same side of the needle. The rotary hook moves the fabric thread to form a loop that fits onto the bobbin thread. When the needle rises, the needle thread passes through the needle plate from outside the bobbin thread and the fabric thread, tightening the loop to form a normal forward sewing stitch. In reverse sewing, the bobbin thread and the fabric thread are on opposite sides of the needle. When the needle rises, the needle thread passes between the bobbin thread and the fabric thread. When the loop is tightened, the thread will knot, forming a wrapped reverse sewing stitch.

[0003] Reverse stitches are detrimental to the flatness and aesthetics of the fabric. To address this issue, some sewing machines on the market are equipped with a rotating mechanism that adjusts the reverse stitch to a forward stitch by rotating the sewing head and shuttle during the reverse stitching process. These sewing machines have a complex structure, higher production costs, and a larger sewing head rotation radius, resulting in excessive space requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a sewing machine that can form a forward stitch while sewing against the grain, and has the characteristics of simpler and more compact structure and lower cost.

[0005] Another objective of this invention is to provide a sewing machine control method that can form a forward stitch in reverse stitching, thereby achieving better sewing results.

[0006] An embodiment of the present invention provides a technical solution: A sewing machine includes a base, a needle plate, a shuttle, and a prying mechanism. The needle plate and the shuttle are mounted on the base, and the shuttle is located below the needle plate. The needle plate has needle holes extending in a vertical direction. The actuating mechanism includes a motor, a planar four-bar linkage, and a lever. The planar four-bar linkage is mounted on the base. The motor is connected to the lever via the planar four-bar linkage. The motor is configured to drive the lever in reverse stitching before the needle goes down, so that the end of the lever away from the planar four-bar linkage moves circumferentially around the axis of the needle hole, moving the portion of the bobbin thread between the needle plate and the rotary hook past the axis of the needle hole.

[0007] In an optional embodiment, the planar four-bar linkage includes a motor bracket, a crank, a connecting rod, and a rocker arm. The motor bracket is mounted on the base, the crank and the rocker arm are respectively hinged to the motor bracket, and the connecting rod is respectively hinged to the crank and the rocker arm. The motor is mounted on the motor bracket and connected to the crank, and the lever is connected to the connecting rod.

[0008] In an optional embodiment, the connecting rod has an opposing hinged end and a suspended end, and a hinge portion located between the hinged end and the suspended end, the hinged end being hinged to the crank, the hinge portion being hinged to the rocker arm, and the lever being connected to the suspended end.

[0009] In an optional embodiment, the motor bracket includes a bracket body and a cantilever. One end of the cantilever is connected to the bracket body, and the other end extends to the outside of the bracket body. The crank is hinged to the bracket body, and one end of the rocker arm is hinged to the end of the cantilever away from the bracket body.

[0010] In an optional embodiment, the crank has an eccentrically arranged input end and output end, the input end being mounted on the motor bracket via a first bearing and coaxially connected to the motor shaft of the motor; A second bearing is coaxially sleeved on the side wall of the output end, and a bearing collar is provided on the connecting rod, with the bearing collar coaxially sleeved on the outer ring of the second bearing.

[0011] In an optional embodiment, the motor bracket has a first stepped hole and a second stepped hole arranged coaxially on opposite sides, and the two are connected by a transition hole extending along the same axis. The first bearing is coaxially mounted in the first stepped hole, the input end is coaxially embedded in the inner ring of the first bearing, the motor is embedded in the second stepped hole, and the motor shaft of the motor passes through the transition hole and is coaxially inserted into the input end.

[0012] In an alternative embodiment, the planar four-bar linkage is positioned vertically between the needle plate and the rotary hook.

[0013] In an optional implementation, the plane containing the planar four-bar linkage is perpendicular to the axis of the pinhole.

[0014] In an alternative implementation, the lever extends in a straight line.

[0015] This invention also provides a sewing machine control method applied to the aforementioned sewing machine. The sewing machine includes a base, a needle plate, a rotary hook, and a shifting mechanism. The needle plate and the rotary hook are mounted on the base, with the rotary hook positioned below the needle plate. The needle plate has a needle hole extending vertically. The shifting mechanism includes a motor, a planar four-bar linkage, and a shift lever. The planar four-bar linkage is mounted on the base. The motor is connected to the shift lever via the planar four-bar linkage. The motor is configured to drive the shift lever in reverse stitching before the needle enters the sewing position, causing one end of the shift lever away from the planar four-bar linkage to move circumferentially around the axis of the needle hole, shifting the portion of the thread between the needle plate and the rotary hook beyond the axis of the needle hole. The sewing machine control method includes: The feeding trajectory of the sewing machine is obtained based on the sewing pattern; During the sewing process with a preset number of stitches before each start of the sewing, the motor is kept stationary. After completing the pre-set number of stitches, the motor is started or stopped according to the direction of the feed trajectory corresponding to each subsequent stitch.

[0016] In an optional implementation, the step of controlling the motor to start or stop according to the feeding trajectory includes: If the direction of the feeding trajectory corresponding to the current needle is the forward sewing direction, then control the motor to remain stopped; If the direction of the feed trajectory corresponding to the current needle is the reverse sewing direction, then before the needle goes down, the motor is controlled to start, so as to drive the lever to move the part of the bottom thread between the needle plate and the rotary hook to pass the axis of the needle hole.

[0017] Compared to existing technologies, the sewing machine provided by this invention is equipped with a shifting mechanism. The motor of the shifting mechanism is connected to the shift lever via a planar four-bar linkage. In reverse sewing, the planar four-bar linkage, driven by the motor, moves the shift lever to shift the portion of the bobbin thread between the needle plate and the rotary hook to the axis passing over the needle eye. This ensures that the bobbin thread and the fabric thread are on the same side of the needle, preventing the fabric thread from passing between the bobbin thread and the fabric thread, thus preventing knots and forming a straight stitch. By using a shifting mechanism to adjust the bobbin position instead of a traditional rotating mechanism to rotate the machine head, the shifting mechanism has a simple structure, significantly reduced number of parts, and is easier to maintain, resulting in a simpler, more compact overall machine structure that occupies less space. Therefore, the sewing machine provided by this invention has the advantages of being able to form a straight stitch even in reverse sewing, and features a simpler, more compact structure and lower cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of a sewing machine provided for an embodiment of the present invention; Figure 2 A partial structural schematic diagram of a sewing machine provided for an embodiment of the present invention; Figure 3 This is a schematic diagram of the actuation mechanism; Figure 4 This is a schematic diagram of the lever's movement trajectory; Figure 5 This is a cross-sectional schematic diagram of the actuating mechanism; Figure 6 for Figure 5 Enlarged view of region A in the middle; Figure 7 A flowchart illustrating a sewing machine control method provided for an embodiment of the present invention; Figure 8 for Figure 7 A flowchart of a sub-step of step S103.

[0020] Icons: 100-Sewing machine; 110-Base; 120-Needle plate; 121-Needle hole; 130-Rotary hook; 140-Actuating mechanism; 141-Motor; 1411-Motor shaft; 142-Actuating lever; 143-Motor bracket; 1431-Bracket body; 1432-Cantilever; 1433-First step hole; 1434-Second step hole; 1435-Transition hole; 144-Crank; 145-Connecting rod; 1451-Hinged end; 1452-Suspended end; 1453-Hinged part; 1454-Bearing collar; 146-Rock arm; 147-First bearing; 148-Second bearing; 150-Needle. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0026] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] Example Please see Figure 1 and Figure 2 , Figure 1 The diagram shown is a structural schematic of the sewing machine 100 provided in this embodiment. Figure 2 The diagram shown is a partial structural schematic of the sewing machine 100.

[0029] The sewing machine 100 provided in this embodiment includes a base 110, a needle plate 120, a rotary hook 130, and a shifting mechanism 140. The needle plate 120 and the rotary hook 130 are mounted on the base 110, with the rotary hook 130 located below the needle plate 120. The needle plate 120 has a needle hole 121 extending in the vertical direction. The shifting mechanism 140 is mounted on the base 110 and is used to shift the portion of the bobbin thread between the needle plate 120 and the rotary hook 130 across the axis of the needle hole 121 during reverse sewing, so that the bobbin thread and the top thread on the fabric side are on the same side of the axis of the needle hole 121.

[0030] It is understood that the sewing machine 100 provided in this embodiment also includes conventional configurations such as a needle bar mechanism for driving the needle 150, a rotary hook 130 drive mechanism for driving the rotary hook 130 to rotate, a feeding device for feeding the sewing material, and a thread cutting device for cutting the thread, which will not be described in detail in this embodiment.

[0031] In practical applications, the feeding device drives the fabric in a forward motion to perform a straight stitch. The actuating mechanism 140 remains stationary. The needle 150 passes through the fabric and the needle hole 121 on the needle plate 120 from top to bottom, carrying the top thread to the space between the needle plate 120 and the rotary hook 130. At this time, the bottom thread between the needle plate 120 and the rotary hook 130 is on the same side of the needle 150 as the top thread on the panel side. As the needle 150 rises, the rotary hook 130 rotates, hooking the top thread on the fabric side to form a loop. As it continues to rotate, the loop is placed on the bottom thread. As the needle 150 continues to rise, it tightens the loop to form a straight stitch.

[0032] During the reverse movement of the fabric driven by the feeding device, reverse stitching is performed. Before the needle 150 inserts, the actuating mechanism 140 is activated, moving the portion of the bobbin thread between the needle plate 120 and the rotary hook 130 to cross the axis of the needle hole 121. Then, the needle 150 inserts, carrying the top thread to the area between the needle plate 120 and the rotary hook 130. Because the actuating mechanism 140 has pre-adjusted the position of the bobbin thread, the bobbin thread and the top thread on the panel side are both on the same side of the needle 150. Therefore, under the combined action of the rotary hook 130 and the needle 150, a forward stitch is formed.

[0033] It is understandable that the top thread on the needle 150 side refers to the part of the top thread that is on one side of the needle 150 and extends to the sewing machine 100 spool, while the top thread on the sewing thread side refers to the part of the top thread that is on the other side of the needle 150 and extends to the part that interweaves with the bottom thread on the fabric.

[0034] Please refer to the following: Figure 3 , Figure 3 The diagram shown is a schematic diagram of the toggle mechanism 140.

[0035] The actuating mechanism 140 provided in this embodiment includes a motor 141, a planar four-bar linkage, and a lever 142. The planar four-bar linkage is mounted on the base 110. The motor 141 is connected to the lever 142 via the planar four-bar linkage. The motor 141 is configured to drive the lever 142 to move before the needle 150 inserts in the reverse sewing case, so that the end of the lever 142 away from the planar four-bar linkage moves circumferentially around the axis of the needle hole 121, and moves the portion of the bobbin thread between the needle plate 120 and the rotary hook 130 to cross the axis of the needle hole 121.

[0036] Specifically, in the vertical direction, the planar four-bar linkage is located between the needle plate 120 and the rotary hook 130, and the plane in which the planar four-bar linkage is located is perpendicular to the axis of the needle hole 121. When the motor 141 drives the planar four-bar linkage to move, the planar four-bar linkage drives the lever 142 to move synchronously. The movement trajectory of the end of the lever 142 away from the planar four-bar linkage is a circumferential closed-loop trajectory. The plane in which this circumferential closed-loop trajectory is located is perpendicular to the axis of the needle hole 121 and surrounds the axis of the needle hole 121.

[0037] Please refer to the following: Figure 4 , Figure 4 The diagram shows the trajectory of lever 142.

[0038] In the plane containing the planar four-bar linkage, a coordinate system is established with the projection point O of the pinhole 121 axis as the origin. The Z arrow points to the left, the Y arrow points to the right, the H arrow points to the rear, and the Q arrow points to the front. Figure 4 The dotted line in the diagram represents the motion trajectory of the free end of lever 142, that is, the motion trajectory of the end of lever 142 that is away from the planar four-bar linkage.

[0039] Preferably, in the initial state where the motor 141 is stopped, the actuating mechanism 140 in this embodiment is located to the left rear of the needle hole 121 axis. In the case of reverse sewing, the motor 141 is started before the needle 150 inserts, causing the free end of the lever 142 to move from the front of the needle hole 121 axis to the rear of the needle hole 121 axis. During this process, the free end of the lever 142 actuates the bottom thread, causing the bottom thread between the rotary hook 130 and the needle plate 120 to cross the needle hole 121 axis, and the lever 142 completes passing directly under the needle hole 121.

[0040] Subsequently, motor 141 continues to operate, needle 150 descends, carrying the top thread to between needle plate 120 and rotary hook 130. The free end of lever 142 gradually detaches from the bobbin thread. After detaching from lever 142, the bobbin thread is blocked by needle 150 and remains on the side of needle 150 where the top thread is located on the fabric side, while the top thread on the needle 150 side is outside the bobbin thread and fabric side. As needle 150 descends and rises, rotary hook 130 rotates and hooks the top thread on the fabric side, forming a loop that surrounds the bobbin thread. As needle 150 continues to rise, it causes the loop to tighten, forming a straight stitch.

[0041] In order to ensure that the lever 142 can release the bottom line smoothly, the lever 142 in this embodiment extends in a straight line, specifically, the part of the lever 142 except for the end connected to the planar four-bar linkage extends in a straight line.

[0042] Please refer to the following: Figure 5 and Figure 6 , Figure 5 The diagram shown is a cross-sectional view of the actuating mechanism 140. Figure 6 As shown Figure 5 An enlarged schematic diagram of region A in the middle.

[0043] In this embodiment, the planar four-bar linkage includes a motor bracket 143, a crank 144, a connecting rod 145, and a rocker arm 146. The motor bracket 143 is mounted on the base 110. The crank 144 has an eccentrically positioned input end and an output end. Its output end and the rocker arm 146 are respectively hinged to the motor bracket 143. The connecting rod 145 is respectively hinged to the output end of the crank 144 and the rocker arm 146. The motor 141 is mounted on the motor bracket 143 and connected to the input end of the crank 144. The lever 142 is connected to the connecting rod 145.

[0044] Specifically, the connecting rod 145 has a hinged end 1451 and a suspended end 1452, and a hinge portion 1453 located between the hinged end 1451 and the suspended end 1452. The hinged end 1451 is hinged to the crank 144, the hinge portion 1453 is hinged to the rocker arm 146, and the lever 142 is connected to the suspended end 1452.

[0045] During the operation of motor 141, the input end of crank 144 rotates, causing its output end to rotate eccentrically, which in turn drives connecting rod 145 to move synchronously. Since connecting rod 145 is also restricted by the movement of rocker arm 146, it moves in the forward-backward direction while simultaneously oscillating in the left-right direction under the influence of crank 144, thereby causing the free end of lever 142 to form... Figure 4 The circumferential closed-loop motion trajectory is shown by the curve in the middle.

[0046] The motor bracket 143 in this embodiment includes a bracket body 1431 and a cantilever 1432. One end of the cantilever 1432 is connected to the bracket body 1431, and the other end extends to the outside of the bracket body 1431. The crank 144 is hinged to the bracket body 1431, and one end of the rocker arm 146 is hinged to the end of the cantilever 1432 away from the bracket body 1431.

[0047] Specifically, the support body 1431 has a first stepped hole 1433 and a second stepped hole 1434 coaxially arranged on opposite sides, which are connected by a transition hole 1435 extending along the same axis. The first bearing 147 is coaxially installed in the first stepped hole 1433, the input end of the crank 144 is coaxially embedded in the inner ring of the first bearing 147, the motor 141 is embedded in the second stepped hole 1434, and the motor shaft 1411 of the motor 141 passes through the transition hole 1435 and is coaxially inserted into the input end of the crank 144.

[0048] By providing a first stepped hole 1433 and a second stepped hole 1434 on the support body 1431, the motor 141 and crank 144 can be quickly positioned, reducing assembly difficulty and improving assembly accuracy. In this embodiment, a second bearing 148 is coaxially sleeved on the side wall of the output end, and a bearing collar 1454 is provided on the hinge end 1451 of the connecting rod 145. The bearing collar 1454 is coaxially sleeved on the outer ring of the second bearing 148. A hinge hole is provided through the hinge portion 1453 of the connecting rod 145, and the hinge hole is hinged to the end of the rocker arm 146 away from the cantilever 1432 through a rotating shaft.

[0049] In summary, the sewing machine 100 provided in this embodiment, by configuring the actuating mechanism 140 to actuate the bobbin across the axis of the needle hole 121 during reverse sewing, makes the bobbin and the top thread on the fabric side on the same side of the needle 150, thereby preventing the top thread on the needle 150 side from passing between the bobbin and the top thread on the fabric side, that is, preventing the top thread from knotting and forming a straight stitch.

[0050] Therefore, the sewing machine 100 provided by the present invention can form a forward stitch when sewing against the grain, and compared with existing products equipped with a rotating mechanism, it has the characteristics of simpler and more compact structure and lower cost.

[0051] In addition, this embodiment also provides a sewing machine control method, applied to the aforementioned sewing machine 100, which can form a forward stitch even when sewing against the grain, thereby achieving a better sewing effect. Please refer to [link / reference]. Figure 7 , Figure 7 The diagram shown is a flowchart of the sewing machine control method, which may include: Step S101: Obtain the feeding trajectory of the sewing machine 100 according to the sewing pattern.

[0052] In practical applications, the sewing pattern is input into the control system of the sewing machine 100. The control system can automatically generate a feeding trajectory based on the sewing pattern. The feeding trajectory refers to the trajectory of the sewing material movement driven by the feeding device.

[0053] In step S102, during the pre-set number of stitches before each start of sewing, the control motor 141 is kept stopped.

[0054] Understandably, each start of a stitch includes both the initial stitch and the subsequent stitching after the thread has been cut during the sewing process.

[0055] The sewing machine 100 is equipped with a small bird's nest device to shorten the starting stitch. In this embodiment, in order to prevent the actuating mechanism 140 from interfering with the small bird's nest device of the sewing machine 100, the control motor 141 is kept stopped within the preset number of stitches before the start of the sewing, that is, the actuating device does not move.

[0056] Preferably, the preset number of stitches in this embodiment is four stitches, that is, the motor 141 is kept stopped during the first four stitches of each sewing.

[0057] In step S103, after completing the pre-set number of stitches, the motor 141 is started or stopped according to the direction of the feeding trajectory corresponding to each subsequent stitch.

[0058] Please refer to the following: Figure 8 , Figure 8 The diagram shown is a flowchart of one sub-step of step S103. Step S103 may include the following sub-steps: In sub-step S1031, if the direction of the feeding trajectory corresponding to the current needle is the positive sewing direction, then control the motor 141 to remain stopped.

[0059] In sub-step S1032, if the direction of the feeding trajectory corresponding to the current needle is the reverse sewing direction, then before the needle 150 goes down, control the motor 141 to start, so as to drive the lever 142 to move the part of the bottom thread between the needle plate 120 and the rotary hook 130 to pass the axis of the needle hole 121.

[0060] If the direction of the feed path corresponding to the current needle is the reverse stitch direction, then the motor 141 is started before the needle 150 goes down, causing the free end of the lever 142 to move the bobbin thread between the rotary hook 130 and the needle plate 120 across the axis of the needle hole 121. This ensures that after the subsequent needle 150 goes down, the bobbin thread disengages from the lever 142 and is blocked by the needle 150, remaining on the side of the fabric side of the needle 150 where the top thread is located, thus forming a forward stitch.

[0061] As can be seen, the sewing machine control method provided in this embodiment can form a forward stitch when sewing against the grain, thus achieving a better sewing effect.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sewing machine, characterized in that, It includes a base (110), a needle plate (120), a rotary hook (130) and a toggle mechanism (140). The needle plate (120) and the rotary hook (130) are mounted on the base (110), and the rotary hook (130) is located below the needle plate (120). The needle plate (120) has a needle hole (121) extending in the vertical direction. The actuating mechanism (140) includes a motor (141), a planar four-bar linkage, and a lever (142). The planar four-bar linkage is mounted on the base (110). The motor (141) is connected to the lever (142) via the planar four-bar linkage. The motor (141) is configured to drive the lever (142) to move before the needle (150) goes down in the reverse sewing case, so that the end of the lever (142) away from the planar four-bar linkage moves circumferentially around the axis of the needle hole (121), and moves the part of the bottom thread between the needle plate (120) and the rotary hook (130) to cross the axis of the needle hole (121).

2. The sewing machine according to claim 1, characterized in that, The planar four-bar linkage includes a motor bracket (143), a crank (144), a connecting rod (145), and a rocker arm (146). The motor bracket (143) is mounted on the base (110). The crank (144) and the rocker arm (146) are respectively hinged to the motor bracket (143). The connecting rod (145) is respectively hinged to the crank (144) and the rocker arm (146). The motor (141) is mounted on the motor bracket (143) and connected to the crank (144), and the lever (142) is connected to the connecting rod (145).

3. The sewing machine according to claim 2, characterized in that, The connecting rod (145) has a hinged end (1451) and a suspended end (1452) opposite each other, and a hinge portion (1453) located between the hinged end (1451) and the suspended end (1452). The hinged end (1451) is hinged to the crank (144), the hinge portion (1453) is hinged to the rocker arm (146), and the lever (142) is connected to the suspended end (1452).

4. The sewing machine according to claim 2, characterized in that, The motor bracket (143) includes a bracket body (1431) and a cantilever (1432). One end of the cantilever (1432) is connected to the bracket body (1431), and the other end extends to the outside of the bracket body (1431). The crank (144) is hinged to the bracket body (1431), and one end of the rocker arm (146) is hinged to the end of the cantilever (1432) away from the bracket body (1431).

5. The sewing machine according to claim 2, characterized in that, The crank (144) has an eccentrically set input end and output end. The input end is mounted on the motor bracket (143) via a first bearing (147) and is coaxially connected to the motor shaft (1411) of the motor (141). A second bearing (148) is coaxially sleeved on the side wall of the output end, and a bearing collar (1454) is provided on the connecting rod (145). The bearing collar (1454) is coaxially sleeved on the outer ring of the second bearing (148).

6. The sewing machine according to claim 5, characterized in that, The motor bracket (143) has a first stepped hole (1433) and a second stepped hole (1434) arranged coaxially on opposite sides, and the two are connected by a transition hole (1435) extending along the same axis. The first bearing (147) is coaxially mounted in the first stepped hole (1433), the input end is coaxially embedded in the inner ring of the first bearing (147), the motor (141) is embedded in the second stepped hole (1434), and the motor shaft (1411) of the motor (141) passes through the transition hole (1435) and is coaxially inserted into the input end.

7. The sewing machine according to claim 1, characterized in that, In the vertical direction, the planar four-bar linkage is located between the needle plate (120) and the rotary hook (130).

8. The sewing machine according to claim 1, characterized in that, The plane containing the planar four-bar linkage is perpendicular to the axis of the pinhole (121).

9. The sewing machine according to claim 1, characterized in that, The lever (142) extends in a straight line.

10. A sewing machine control method, applied to the sewing machine (100) as described in any one of claims 1-9, characterized in that, The sewing machine control method includes: The feeding trajectory of the sewing machine (100) is obtained according to the sewing pattern; During the sewing process of the preset number of stitches before each start of the sewing, the motor (141) is kept stopped; After completing the pre-set number of stitches, the motor (141) is started or stopped according to the direction of the feeding trajectory corresponding to each subsequent stitch.

11. The sewing machine control method according to claim 10, characterized in that, The step of controlling the motor (141) to start or stop according to the feeding trajectory includes: If the direction of the feeding trajectory corresponding to the current needle is the positive sewing direction, then control the motor (141) to remain stopped; If the direction of the feeding trajectory corresponding to the current needle is the reverse sewing direction, then before the needle (150) goes down, control the motor (141) to start, so as to drive the lever (142) to move the part of the bottom thread between the needle plate (120) and the rotary hook (130) to cross the axis of the needle hole (121).

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