CN217869414U - Overedger - Google Patents

Abstract

The utility model provides an overedger, which comprises an upper curved needle, a needle plate, a main shaft connected with the upper curved needle and a presser foot component, wherein the needle plate comprises a cloth placing surface, the presser foot component comprises a cloth pressing plate suspended above the needle plate, and the orthographic projection of the cloth pressing plate on the cloth placing surface forms a cloth pressing coverage area; the main shaft can rotate and drive the upper curved needle to reciprocate relative to the needle plate; when the overedger stops the needle, the main shaft stops rotating, and the orthographic projection of the upward curved needle on the cloth placing surface leaves the cloth pressing coverage area.

Description

Overedger

Technical Field

The utility model relates to a sewing technical field especially relates to an overedger.

Background

An overlock machine is a machine for sewing a fabric overlock, in which a cloth to be sewn is pressed against a needle plate by a cloth pressing plate during sewing, and the cloth pressing plate is also lifted or lowered during suspension of sewing and at the end of sewing. With the trend of the structural design of the overedger towards miniaturization and light weight, the cloth pressing space provided by the existing overedger is extremely limited, namely the space between the cloth pressing plate and the needle plate when the cloth pressing plate is lifted.

In order to realize easy taking out and putting in of sewn cloth, the main shaft is generally stopped to rotate when the machine needle is at the upper limit position in the industry, the distance between the machine needle and the needle plate is the largest at the moment, and the cloth pressing space provided by the overedger is the largest theoretically. In practical application, the upper curved needle in the overedger reaches the periphery of the needle when the needle reaches the upper limit position of the upper curved needle, and even moves above the cloth pressing plate, so that a part of cloth pressing space is occupied, the allowable stroke of the cloth pressing plate relative to the rising movement of the needle plate is shortened, collision and interference with the cloth pressing plate are possible, and the sewing cloth with thick cloth is difficult to place or take out.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides an overlock machine, this kind of overlock machine can improve the situation that present compress board lifting stroke is limited, the cloth is put into the compress space difficulty.

The utility model provides a overedger, including last looper, faller, connect the main shaft and presser foot subassembly of last looper, the faller includes the cloth placing face, the presser foot subassembly includes the compress board that hangs above the faller, the orthographic projection of compress board on cloth placing face forms the compress coverage area; the main shaft can rotate and drive the upper curved needle to reciprocate relative to the needle plate; when the overedger stops the needle, the main shaft stops rotating, and the orthographic projection of the upward curved needle on the cloth placing surface leaves the cloth pressing coverage area.

In one embodiment, the overedger further comprises a needle, and the main shaft is connected with the needle and can drive the needle to reciprocate and lift relative to the needle plate; the needle has a rising limit position, when the rotation angle of the main shaft is at a preset needle stopping angle, the position of the needle is the needle stopping position, and the height difference between the needle stopping position and the rising limit position is not more than 3 mm.

The movement of the machine needle and the movement of the upper bent needle are mutually related, and both the machine needle and the upper bent needle are driven by the main shaft to move.

In one embodiment, the rotation angle of the main shaft is not less than 45 ° and not more than 55 ° from the time when the needle is at the ascent limit position to the time when the needle is at the needle stop position.

Among the present like product, main shaft stall when needle stop position, compare in prior art the needle stop at the extreme position that rises, the utility model discloses well main shaft has rotated 45 ~ 55 more, and the last looper is driven and one section stroke of further motion is backed out the compress space.

In one embodiment, when the rotation angle of the main shaft is at the preset needle stop angle, the horizontal distance between the needle point of the upward bending needle and the center of the leftmost needle in the needles is 6 mm-8 mm.

In one embodiment, the upper looper and the needle board are vertically displaced from each other when the spindle rotation angle is at the preset needle stop angle.

In one embodiment, the overedger further comprises a magnetic element and a hall sensor, wherein the magnetic element is connected with the main shaft and can rotate along with the main shaft, and the hall sensor determines the rotation angle of the main shaft by sensing the position of the magnetic element; when the Hall sensor senses that the rotation angle of the main shaft reaches the preset needle stopping angle, the main shaft stops rotating.

In one embodiment, the overlock sewing machine further comprises a driving motor and a rotary encoder in communication connection with the driving motor, wherein the rotary encoder determines the rotation angle of the spindle by sensing the position of a rotor of the driving motor, and the driving motor drives the spindle to stop the spindle from rotating when the rotary encoder senses that the rotation angle of the spindle reaches a preset needle stopping angle.

In one embodiment, the overlock sewing machine further comprises a driving motor, a grating scale and a photoelectric encoder, wherein the grating scale is arranged on a rotor of the driving motor, and the photoelectric encoder can sense the position of the grating scale and generate counting pulses to determine the rotation angle of the main shaft; when the photoelectric encoder senses that the rotation angle of the main shaft reaches the preset needle stopping angle, the driving motor brakes the main shaft to stop the main shaft from rotating.

In one embodiment, the presser foot assembly further comprises a pedal connected with the cloth pressing plate, the overedger further comprises a sensor arranged on the pressing plate and a driver connected with the main shaft, the sensor is in communication connection with the driver and used for sensing the action of the pedal, and the driver can drive the main shaft to rotate according to the sensing condition of the sensor and brake the main shaft when the rotating angle of the main shaft reaches a preset needle stopping angle, so that the main shaft stops rotating.

In one embodiment, the overlock machine further comprises a presser foot assembly and a thread cutting assembly, wherein the presser foot assembly comprises a presser foot tongue, the thread cutting assembly comprises a tool holder, and one side of the presser foot tongue, which is relatively close to the tool holder, is in curved surface transition.

So set up, when following presser foot subassembly lifting and keeping away from the faller motion relatively, the presser foot tongue can not collide the interference with the blade holder, can not restrict the stroke that the presser plate lifting was kept away from the faller.

In one embodiment, the overedger further comprises a presser foot assembly and a thread cutting assembly, wherein the presser foot assembly comprises an auxiliary presser foot, the thread cutting assembly comprises a tool apron, and one side of the auxiliary presser foot, which is relatively close to the tool apron, is parallel to the needle plate.

With the arrangement, the thickness of the auxiliary presser foot is smaller, and the occupied space volume is smaller, so that the cloth pressing plate can be formed by larger lifting displacement, the distance between the cloth pressing plate and the needle plate is further increased, and the maximum value of the thickness of cloth which can be placed between the cloth pressing plate and the needle plate is increased.

Compared with the prior art, when the overedger provided by the utility model stops sewing, the upper curved needle can be at least separated from the area vertically above the cloth pressing covering area, thereby reducing the occupation of the upper curved needle on the cloth pressing space and eliminating the possibility of collision and interference between the upper curved needle and the cloth pressing plate; the compress board also can be at the lifting activity of bigger vertical distance within range, has increased the relative faller upward movement's of compress board maximum range of motion, has increased the maximum distance value of compress board to the faller cloth laying face, can allow thicker cloth to put into between compress board and the faller from this, therefore the utility model provides a hemming machine can be used for making up thicker cloth, improves the problem that current hemming machine can only make up thinner cloth, place difficulty when thicker cloth.

Drawings

Fig. 1 is a schematic partial structural view of an overlock sewing machine according to an embodiment of the present invention at a first viewing angle;

FIG. 2 is an enlarged partial schematic view of the overlock machine of FIG. 1 at A;

FIG. 3 is a schematic view of a portion of the overedger shown in FIG. 1 with the spindle stopped;

FIG. 4 is a schematic view of a portion of the overlock machine shown in FIG. 1 with the machine needle in an upper limit position;

FIG. 5 is a diagram illustrating the relationship between the rotation angle of the main shaft and the horizontal displacement of the upper curved needle according to an embodiment of the present invention;

FIG. 6 is a schematic view of a portion of the overlock machine according to an embodiment of the present invention at a second viewing angle;

fig. 7 is a schematic view of a part of the structure of the presser foot tongue according to an embodiment of the present invention;

fig. 8 is a schematic view of a partial structure of an auxiliary presser foot according to an embodiment of the present invention.

Description of reference numerals:

11. a needle; 12. upward bending the needle; 21. a first transmission mechanism; 22. a second transmission mechanism; 30. a main shaft; 31. a first eccentric section; 32. a second eccentric section; 33. a turnover section; 40. a needle plate; 41. laying cloth; 50. a presser foot assembly; 51. a cloth pressing plate; 52. a presser foot tongue; 521. a transition curved surface; 53. an auxiliary presser foot; 61. a driver; 62. a hand wheel; 63. a motor fan blade; 70. a log unit; 72. a magnetic element; 91. a tool apron.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

The utility model provides a hemming machine, hemming machine are a machinery for making up fabrics lockstitch, including frame, rotatable installing in the main shaft 30 of frame, be connected with the main shaft 30 drive for produce drive main shaft 30 rotate required power the driver 61, set up in presser foot subassembly 50 of frame, mobile mounting and the eedle 11 that is connected with main shaft 30 respectively and go up looper 12 in the presser foot subassembly 50 of frame.

Referring to fig. 1-2, the needle plate 40 includes a cloth placing surface 41 for carrying cloth to be sewn, in some embodiments, the cloth placing surface 41 is a plane vertically arranged upward, the presser foot assembly 50 includes a pedal and a cloth pressing plate 51 connected to the pedal, the cloth pressing plate 51 is movably suspended above the needle plate 40 and is arranged opposite to the cloth placing surface 41, and the pedal can drive the cloth pressing plate 51 to move relatively close to or far away from the needle plate 40 after being stepped by a user. The cloth pressing plate 51 is used for placing the sewn cloth between the cloth pressing plate 51 and the needle plate 40, and the cloth pressing plate 51 needs to be lifted away from the needle plate 40 when the cloth is placed in, so that the maximum distance of the cloth pressing plate 51 lifted relative to the needle plate 40/cloth placing surface 41 directly determines the maximum thickness dimension of the cloth which can be placed between the cloth pressing plate 51 and the needle plate 40.

The main shaft 30 comprises a turnover section 33 and further comprises a first eccentric section 31 and a second eccentric section 32 which are fixedly connected with the turnover section 33, the main shaft 30 rotates by taking the axis of the turnover section 33 as the center, the first eccentric section 31 is connected with a first transmission mechanism 21, the first transmission mechanism 21 is connected with the machine needle 11, the second eccentric section 32 is connected with a second transmission mechanism 22, and the second transmission mechanism 22 is connected with the upper bent needle 12. If the plane on which the cloth placing surface 41 of the needle plate 40 is located is used as a reference surface, the needle 11 and the upper looper 12 are located on the vertically upper side of the reference surface, wherein the needle 11 and the needle plate 40 are kept oppositely arranged, and the space between the cloth pressing plate 51 and the needle plate 40 when being lifted, namely the movable space for theoretically lifting or lowering the cloth pressing plate 51 relative to the needle plate 40, can be called as a cloth pressing space.

The driver 61 drives the main shaft 30 to rotate along a fixed rotation direction, and if the driver 61 can drive the main shaft 30 to continuously rotate along the fixed option, the first eccentric section 31 can drive the machine needle 11 to reciprocate up and down relative to the needle plate 40 through the first transmission mechanism 21, and the second eccentric section 32 can drive the upper curved needle 12 to reciprocate transverse relative to the cloth placing surface 41 of the needle plate 40 through the second transmission mechanism 22, that is, the orthographic projection of the upper curved needle 12 on the plane where the cloth placing surface 41 is located can be switched between a state of being separated from the cloth placing surface 41 and a state of being overlapped on the cloth placing surface 41, in other words, the upper curved needle 12 can reciprocate and enter or exit between the machine needle 11 and the cloth pressing plate 51.

During the actual operation of the overlock machine, the main shaft 30 may stop rotating but the overlock machine is not powered off, and the needle 11 and the upper curved needle 12 stop moving respectively to stop sewing, which is called the needle stop of the overlock machine. For example, when the cloth to be sewn needs to be taken out from between the cloth presser plate 51 and the needle plate 40, or when the cloth to be sewn needs to be put in between the cloth presser plate 51 and the needle plate 40, the main shaft 30 needs to be temporarily stopped and the sewing operation of the needle 11 and the upper looper 12 needs to be stopped.

The existing overedger generally stops the rotation of a main shaft when a machine needle is positioned at an upper limit position, the distance between the machine needle and a needle plate is the largest at the moment, and theoretically, the overedger can provide the largest cloth pressing space. In practice, however, the upwardly bent needle reaches around the needle when the needle reaches its upper limit position and may even move above the cloth pressing plate, which takes up a part of the cloth pressing space, shortens the allowable stroke of the cloth pressing plate with respect to the upward movement of the needle plate, and may collide with the cloth pressing plate.

In view of this, the utility model provides a overedger still includes odometry unit 70, odometry unit 70 and driver 61 communication connection, and the internal integration has electronic control program, can sense the turned angle/turned angle displacement volume of main shaft 30 to when the turned angle of main shaft 30 is in preset needle stopping angle, odometry unit 70 can generate needle stopping brake instruction, and send this instruction to driver 61 in order to brake main shaft 30 to rotate, and last curved needle 12 stop position is as shown in fig. 3, and the orthographic projection of curved needle 12 on putting the plane that cloth surface 41 was located leaves the compress coverage area this moment. The cloth pressing covering area is an orthographic projection of the cloth pressing plate 51 on the cloth placing surface 41, in other words, the upper bending needle 12 and the cloth pressing covering area are vertically displaced from each other, and then the cloth pressing plate 51 does not collide with the upper bending needle 12 even if the cloth pressing plate is relatively lifted away from the cloth placing surface 41.

Referring to fig. 5, fig. 5 is a diagram showing a relationship between a rotation angle of the main shaft 30 and a displacement component of the upper looper 12 in a horizontal direction according to an embodiment of the present invention, wherein a horizontal axis represents the rotation angle of the main shaft 30, and a vertical axis represents a movement displacement amount of the upper looper 12 in the horizontal direction (for convenience of description, hereinafter, referred to as a horizontal displacement amount of the upper looper 12). As shown in fig. 5, the function with the rotation angle of the main shaft 30 as an independent variable and the horizontal displacement of the upper looper 12 as a dependent variable is a periodic function, where γ 'is an angle interval of the rotation angle of the main shaft 30 when the needle 11 reaches its upper limit position, β' is a preset needle stop angle interval, and fig. 5 shows γ 'and β' intervals in one period. The function of the odometer unit 70 is to send a needle stop brake command to the actuator 61 when the rotation angle of the spindle 30 is in the preset needle stop angle interval, so that the rotation is immediately stopped when the rotation angle of the spindle 30 is in the β' interval.

When the horizontal displacement of the upper curved needle 12 is the reference, that is, the horizontal displacement of the upper curved needle 12 is 0, the needle tip of the upper curved needle 12 is exactly aligned with the needle center at the leftmost side of the needle 11 shown in fig. 3 or 4; when the horizontal displacement of the upper looper 12 is positive, the needle point of the upper looper 12 is located on the right side of the leftmost needle center of the needle 11 shown in fig. 3, and when the horizontal displacement of the upper looper 12 is negative, the needle point of the upper looper 12 is located on the left side of the leftmost needle center of the needle 11 shown in fig. 4. Fig. 3 illustrates the relative position relationship between the cloth pressing plate 51, the needle plate 40, the upper looper 12, and the needle 11 when the rotation of the main shaft 30 is stopped/the rotation angle of the main shaft 30 is within the preset needle stop angle range β', where the position of the needle 11 is the needle stop position, and the rotation of the main shaft 30 is stopped, where the horizontal distance B is 6 mm to 8 mm; fig. 4 shows the relative positional relationship between the cloth presser 51, the needle plate 40, the upper looper 12, and the needle 11 when the needle 11 is at its upper limit position, wherein the horizontal distance C is from 3 mm to 5 mm. In other words, in the conventional overedger, the relative positional relationship between the cloth presser plate 51, the needle plate 40, the upper looper 12, and the needle 11 when the rotation of the main shaft 30 is stopped is as shown in fig. 4.

The improved process and principle of the utility model are as follows: when the relative positions of the cloth pressing plate 51, the needle plate 40, the upper looper 12 and the machine needle 11 are in the state shown in fig. 4, the main shaft 30 is enabled to continue rotating for 45-55 degrees under the condition of not changing the rotating direction until the relative position relationship of the cloth pressing plate 51, the needle plate 40, the upper looper 12 and the machine needle 11 is in the state shown in fig. 3. In the process, the upward curved needle 12 is displaced by 9 mm to 13 mm in the right direction shown in fig. 4, and finally, the upward curved needle 12 exits between the needle 11 and the cloth pressing plate 51, and the needle 11 also moves by 1 mm to 3 mm relatively close to the cloth placing surface 41 of the needle plate 40. Although the needle 11 moves up and down by 1 mm to 3 mm in the vertical direction, the maximum allowable stroke of the lifting motion of the cloth pressing plate 51 is not affected, but the main shaft 30 rotates by 45 degrees to 55 degrees more to drive the upward bending needle 12 to leave the cloth pressing space, so that the stroke of the downward movement of the needle 11 is offset, the maximum distance value between the cloth pressing plate 51 and the cloth placing surface 41 is increased, and thicker cloth can be placed between the cloth pressing plate 51 and the cloth placing surface 41.

It should be understood that the preset needle-stopping angle is not necessarily an angle interval, but may also be a determined angle value, or several determined angle values, when the rotation angle of the main shaft 30 reaches the preset needle-stopping angle value, the odometer unit 70 immediately generates a needle-stopping braking command, and at this time, the driver 61 can quickly respond to the needle-stopping braking command to stop the rotation of the main shaft 30.

Alternatively, in some embodiments, when the rotation angle of the spindle 30 is at the preset needle stop angle and the spindle 30 stops rotating, the upper curved needle 12 completely exits from the area vertically above the needle plate 40, the upper curved needle 12 and the needle plate 40 are vertically displaced from each other, and the orthographic projection of the upper curved needle 12 on the plane where the cloth placing surface 41 is located is separated from the cloth placing surface 41.

In one embodiment, the driver 61 may be a driving motor, the metering unit 70 includes a hall sensor in communication connection with the driver 61, the overedger further includes a handwheel 62, the handwheel 62 is mounted at an end of the main shaft 30 and is fixedly provided with a magnetic element 72, the magnetic element 72 can rotate along with the main shaft 30, and the hall sensor determines a rotation angle of the main shaft 30 by sensing a position of the magnetic element 72. When the hall sensor senses that the rotation angle of the main shaft 30 reaches the preset needle stop angle, the main shaft 30 stops rotating.

In order to arrange the magnetic element 72 conveniently, the magnetic element 72 can be fixedly arranged on the motor blade 63 between the hand wheel 62 and the driver 61; when the position of the magnetic element 72 is set, the position of the magnetic element 72 on the hand wheel 62 can be rotated by 45 degrees to 55 degrees around the axis of the revolving section 33 along the rotation direction of the main shaft 30 by referring to the installation position of the magnetic element 72 in the existing overedger, and after the adjustment, the initial corresponding angle of the magnetic element 72 and the hall sensor is changed, so that the angle when the main shaft 30 stops rotating is rotated by 45 degrees to 55 degrees more than before the adjustment.

It is understood that in other embodiments, the magnetic element 72 may not be necessarily mounted on the motor blade 63, but may be mounted at other positions, as long as the magnetic element 72 can rotate along with the main shaft 30, so that the hall sensor can correctly determine the rotation angle of the main shaft 30 according to its actual position.

In one embodiment, the driver 61 may be a driving motor. The odometer unit 70 may also use a hall sensor, and cooperate with the magnetic element 72, sense the rotation angle of the spindle 30 by reading the hall position signal value of the hall sensor, and preset the needle stop position angle, and when the hall position signal value reaches the needle stop position angle, the program of the odometer unit 70 controls the driving motor to brake. Unlike the above embodiments, in the present embodiment, the spindle 30 is delayed from reaching the needle stop position angle by increasing the needle stop position angle signal by 45 ° to 55 ° without changing the mounting position of the magnetic element 72.

In one embodiment, the driver 61 comprises a driving motor, the metering unit 70 comprises a rotary encoder in communication with the driving motor, the rotary encoder is capable of sensing a rotational position of a rotor of the driving motor to determine a rotational angle of the spindle 30, and the driver 61 brakes the spindle 30 when sensing an angle corresponding to the spindle 30 being rotated to the needle park position, that is, the rotational angle of the spindle 30 reaches a preset needle park angle. In actual operation, the initial position angle signal of the driving motor rotor is set as a reference signal, the angle difference between the needle stop position angle signal and the reference signal is calculated through a program, and the rotation angle displacement of the main shaft 30 from the moment corresponding to the reference signal to the moment corresponding to the needle stop position angle signal can be changed by only increasing the needle stop position angle signal by 45-55 degrees, so that the needle stop position is changed.

In one embodiment, the driver 61 includes a driving motor, and the metering unit 70 includes a grating scale disposed on a rotor of the driving motor and a photoelectric encoder capable of sensing a position of the grating scale and generating a count pulse to determine a rotation angle of the spindle 30. When the photoelectric encoder senses that the main shaft 30 rotates to the angle corresponding to the needle stop position, namely the rotation angle of the main shaft 30 reaches the preset needle stop angle, the driving motor brakes the main shaft 30. In actual operation, the rotor initial position angle signal of the driving motor is set as a reference signal, the angle deviation between the needle stop position angle signal and the reference signal is calculated according to the counting pulse through a program, and the rotation angle displacement of the main shaft 30 from the moment corresponding to the reference signal to the moment corresponding to the needle stop position angle signal can be changed by only increasing the needle stop position angle signal by 45-55 degrees, so that the needle stop position is changed.

In one embodiment, the odometer unit 70 includes a sensor disposed on the pedal, the sensor is in communication with the driver 61, and is capable of sensing the pedal movement and sending a corresponding driving command to the driver 61 according to the sensed pedal movement or position condition to control the driver 61 to rotate by a preset angle until the rotation angle of the main shaft 30 reaches a preset needle stop angle. Different driving instructions correspond to different pedal starting positions and different preset angle amounts, and the main shaft 30 can be stopped at a preset needle stopping angle and can be stopped rotating before the pedal lifts the presser foot.

Referring to fig. 6, 7 and 8, in some embodiments, the overedger further includes a thread cutting assembly including a blade holder 91 for mounting a thread cutter, and the presser foot assembly 50 further includes a presser foot tongue 52 and an auxiliary presser foot 53. The presser foot tongue 52 can move along with the cloth pressing plate 51 to move up or down relative to the needle plate 40, and the auxiliary presser foot 53 can also move along with the cloth pressing plate 51 to move up or down relative to the needle plate 40, wherein one side of the presser foot tongue 52 relatively close to the tool apron 91 is provided with a transitional curved surface 521, and the auxiliary presser foot 53 is in a flat plate-shaped structure, and one side relatively close to the tool apron 91 is parallel to the cloth placing surface 41 of the needle plate 40.

The features of the above-described embodiments may be arbitrarily combined, and for the sake of brevity, all possible combinations of the features in the above-described embodiments are not described, but should be construed as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the features.

It will be appreciated by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be taken as limiting the present invention, and that suitable modifications and variations of the above embodiments are within the scope of the invention as claimed.

Claims (11)

1. An overlock machine, comprising:

an upper curved needle (12);

a needle plate (40) including a cloth discharge surface (41);

the main shaft (30) is connected with the upper curved needle (12) and can rotate and drive the upper curved needle (12) to reciprocate relative to the needle plate (40);

the presser foot assembly (50) comprises a cloth pressing plate (51) suspended above the needle plate (40), and the orthographic projection of the cloth pressing plate (51) on the cloth placing surface (41) forms a cloth pressing coverage area;

when the overedger stops, the main shaft (30) stops rotating, and the orthographic projection of the upper curved needle (12) on the cloth placing surface (41) leaves the cloth pressing coverage area.

2. The overlock machine according to claim 1, further comprising a needle (11), wherein the main shaft (30) is connected with the needle (11) and can drive the needle (11) to reciprocate relative to the needle plate (40);

the needle (11) is provided with a rising limit position, when the rotation angle of the main shaft (30) is at a preset needle stopping angle, the position where the needle (11) is located is a needle stopping position, and the height difference between the needle stopping position and the rising limit position is not more than 3 mm.

3. Overlock machine according to claim 2, characterized in that said spindle (30) has a measure of rotation angle not less than 45 ° and not more than 55 ° from when said needle (11) is in said raised extreme position to when said needle (11) is in said rest position.

4. The overlock machine according to claim 2, wherein a horizontal distance between a center of a leftmost needle of the needles (11) and the needle tip of the upwardly curved needle (12) is 6 mm to 8 mm when the rotation angle of the main shaft (30) is at a preset needle stop angle.

5. Overlock machine according to claim 1, characterized in that said curved-up needle (12) and said needle plate (40) are vertically displaced from each other when said spindle (30) is rotated at a preset needle-stop angle.

6. Overlock machine according to claim 1, characterized in that it further comprises a magnetic element (72) and a hall sensor, said magnetic element (72) being connected to said main shaft (30) and being able to follow said main shaft (30) in rotation, said hall sensor determining the angle of rotation of said main shaft (30) by sensing the position of said magnetic element (72);

when the Hall sensor senses that the rotation angle of the main shaft (30) reaches a preset needle stopping angle, the main shaft (30) stops rotating.

7. The overlock machine according to claim 1, further comprising a drive motor and a rotary encoder in communication with said drive motor, said rotary encoder determining a rotational angle of said spindle (30) by sensing a position of a rotor of said drive motor;

when the rotation coding area senses that the rotation angle of the main shaft (30) reaches a preset needle stopping angle, the driving motor brakes the main shaft (30).

8. The overlock machine according to claim 1, further comprising a drive motor, a raster scale disposed on a rotor of the drive motor, and a photoelectric encoder capable of sensing the raster scale position and generating count pulses to determine the rotational angle of the spindle (30); when the photoelectric encoder senses that the rotation angle of the main shaft (30) reaches a preset needle stopping angle, the driving motor brakes the main shaft (30).

9. The overlock machine according to claim 1, wherein the presser foot assembly (50) further comprises a pedal connected with the cloth pressing plate (51), the overlock machine further comprises a sensor arranged on the pedal and a driver (61) connected with the main shaft (30), the sensor is in communication connection with the driver (61) and used for sensing pedal action, the driver (61) can drive the main shaft (30) to rotate according to the sensing condition of the sensor and brake the main shaft (30) when the rotation angle of the main shaft (30) reaches a preset needle stopping angle.

10. The overlock machine as claimed in claim 1, further comprising a presser foot assembly (50) and a thread cutting assembly, said presser foot assembly (50) including a presser foot tongue (52) and said thread cutting assembly including a tool holder (91), said presser foot tongue (52) being curved relatively close to a side of said tool holder (91).

11. The overlock machine as claimed in claim 1, further comprising a presser foot assembly (50) and a thread cutting assembly, wherein said presser foot assembly (50) includes an auxiliary presser foot (53) and said thread cutting assembly includes a knife seat (91), and wherein a side of said auxiliary presser foot (53) relatively close to said knife seat (91) is parallel to said needle plate (40).

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