Sewing machine and bird nest prevention device therefor

Abstract

The application discloses a sewing machine and a bird nest preventing device thereof, wherein the bird nest preventing device comprises a thread cutting knife, a thread catching plate and a thread clamping plate which are slidably stacked from top to bottom, and further comprises an elastic member arranged between the thread catching plate and the thread clamping plate and a driving rod connected with the thread catching plate; when the driving rod is released, the thread catching plate drives the thread passing through the thread catching plate to move along the longitudinal direction from an initial position to a thread catching position relative to the thread clamping plate and the thread cutting knife, and the thread catching plate and the thread clamping plate clamp the thread; when the driving rod is pulled, the thread catching plate drives the thread clamping plate to continuously move along the longitudinal direction from the thread catching position to a thread cutting position relative to the thread cutting knife, the thread cutting knife cuts the thread passing through the thread catching plate, and the thread clamping plate and the thread catching plate keep clamping the cut thread. The application can perform the two actions of catching the thread and cutting the thread in sequence, can catch the thread in the sewing stage and cut the thread after sewing, avoids the residual thread end being too long, reduces the bird nest problem and is beneficial to improving the sewing quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of garment production equipment, in particular to a sewing machine and a bird nest prevention device thereof. BACKGROUND

[0002] The sewing machine is usually provided with a thread cutting mechanism for cutting the bobbin thread and the top thread after sewing. However, after the thread cutting mechanism cuts the bobbin thread, the remaining top thread end on the sewing material is relatively long, and the remaining top thread end will form an undesirable stitch (i.e. bird nest) in the first few stitches of the next sewing, which affects the quality of the sewing product.

[0003] In order to solve the problem of bird nest in the starting sewing, the existing technology takes measures to hold the top thread during the starting sewing and then releases the top thread after a few stitches of needle sewing. Although this measure can reduce the occurrence of the bird nest problem to a certain extent, the measure cannot cut the top thread, which causes the remaining end of the held top thread to be too long, still affects the appearance of the stitch, cannot completely solve the bird nest problem, and the sewing quality cannot be guaranteed. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a sewing machine and a bird nest prevention device thereof, which can perform the two actions of holding the top thread and cutting the top thread in sequence, can hold the top thread during the starting sewing and can cut the top thread after the starting sewing, avoid the remaining top thread end being too long, effectively reduce the occurrence of the bird nest problem, and help to improve the sewing quality.

[0005] The bird nest prevention device of the sewing machine provided by the present application comprises a thread cutting knife, a thread holding plate and a thread clamping plate which are slidably stacked from top to bottom, an elastic member arranged between the thread holding plate and the thread clamping plate, and a driving rod connected to the thread holding plate.

[0006] When the driving rod is released, the thread holding plate drives the elastic member to stretch, and the threaded top thread is moved along the longitudinal direction from the initial position to the thread holding position relative to the thread clamping plate and the thread cutting knife, and the thread holding plate and the thread clamping plate clamp the top thread.

[0007] When the driving rod is pulled, the thread holding plate drives the thread clamping plate to continue moving along the longitudinal direction from the thread holding position to the thread cutting position relative to the thread cutting knife, the thread cutting knife cuts the top thread on the thread holding plate, and the thread clamping plate and the thread holding plate keep clamping the cut top thread.

[0008] Preferably, the bird nest prevention device further comprises:

[0009] a mounting seat;

[0010] a retaining assembly fixed to the mounting seat and elastically abutting between the thread cutting knife and the thread holding plate, for limiting the thread cutting knife from moving before the thread cutting position.

[0011] Preferably, the side of the thread cutting knife close to the thread holding plate is provided with a limiting protrusion, and the retaining assembly comprises:

[0012] a limiting spring sheet with one end fixed to the mounting base and the other end having a Z-shaped elastic part;

[0013] a limiting slider fixed to the Z-shaped elastic part and longitudinally abutting against the limiting block provided on the mounting base; the limiting slider has a longitudinal limiting surface which abuts against the limiting protrusion before the cutting position.

[0014] Preferably, the side of the thread catching plate has a pushing protrusion, and the limiting slider has a supporting protrusion; when the thread catching plate moves to the cutting position, the supporting protrusion abuts against the side of the thread catching plate; when the thread catching plate moves to the cutting position, the pushing protrusion pushes the supporting protrusion outward in the transverse direction, the longitudinal limiting surface is longitudinally disengaged from the limiting protrusion, and the limiting protrusion abuts against the side guiding surface of the limiting slider in the transverse direction.

[0015] Preferably, the side of the thread catching plate has a pushing hook, and the thread cutting knife has a receiving groove; when the driving rod is continuously pulled, the pushing hook abuts against the receiving groove, the thread catching plate drives the thread clamping plate and the thread cutting knife to move longitudinally from the cutting position to the avoiding position, the thread cutting knife and the thread catching plate both abut against the mounting base in the longitudinal direction, and the limiting protrusion slides along the side guiding surface into the limiting groove provided on the limiting slider.

[0016] Preferably, the device further comprises a connecting pin connected to the driving rod, the top end of the connecting pin has a pushing slider, the side of the thread catching plate integrally has a connecting slider, the pushing slider is slidably arranged in the connecting slot provided on the connecting slider; the side of the thread clamping plate integrally has a connecting arm;

[0017] When the thread catching plate slides from the initial position to the thread catching position in the longitudinal direction, the pushing slider abuts against the connecting arm in the longitudinal direction.

[0018] When the driving rod is continuously pulled, the pushing slider pushes the connecting arm along the connecting slot, the thread clamping plate moves relative to the thread catching plate and the thread cutting knife in the longitudinal direction from the avoiding position to the thread releasing position, and the thread clamping plate releases the clamped thread.

[0019] Preferably, the mounting base has a limiting slot, the side of the thread clamping plate away from the connecting arm integrally has a sliding arm, the sliding arm is hinged with a sliding pin which slidably cooperates with the limiting slot and guides the thread clamping plate to slide in the longitudinal direction from the cutting position to the thread releasing position; when the thread clamping plate slides to the thread releasing position, the sliding pin abuts against the last end of the limiting slot, and the pushing slider abuts against the last end of the connecting slot.

[0020] Preferably, the device further comprises a restoring spring sheet with one end fixed to the thread cutting knife and the other end having a blocking end; when the thread catching plate moves from the thread catching position to the cutting position, the pushing hook pushes away the blocking end into the receiving groove, and the thread catching plate drives the thread cutting knife to move between the cutting position and the avoiding position; when the thread catching plate moves from the cutting position to the thread catching position, the restoring spring sheet is deformed to push away the blocking end, and the pushing hook is disengaged from the receiving groove.

[0021] Preferably, the connecting rod is hinged at one end to the sliding pin and provided with a waist-shaped sliding groove at the other end, the waist-shaped sliding groove is in sliding fit with the connecting pin, and the connecting pin is provided with a limiting stop ring for axially limiting the connecting rod.

[0022] The sewing machine provided by the present application comprises the bird nest preventing device described in any of the above.

[0023] With respect to the background art, the bird nest preventing device of the sewing machine provided by the present application comprises a thread cutter, a thread catching plate, a thread clamping plate, an elastic member and a driving rod, the thread cutter, the thread catching plate and the thread clamping plate are sequentially and slidably stacked from top to bottom, the elastic member is arranged between the thread catching plate and the thread clamping plate, and the driving rod is connected with the thread catching plate.

[0024] At the initial position, the thread passes through the thread catching plate, and the elastic member is in a stretched state.

[0025] When the driving rod is released, the elastic member is contracted, the thread catching plate is driven to move by the elastic force exerted by the elastic member, the thread catching plate drives the passing thread to move relative to the thread clamping plate and the thread cutter, respectively, the thread catching plate moves longitudinally from the initial position to a thread catching position, at the thread catching position, the thread catching plate and the thread clamping plate clamp the thread, and the thread is caught.

[0026] When the driving rod is pulled, the driving rod drives the thread catching plate to continue to move, the thread catching plate drives the thread clamping plate to move relative to the thread cutter, and the thread catching plate and the thread clamping plate move synchronously and longitudinally from the thread catching position to a thread cutting position, at the thread cutting position, the thread cutter cuts the thread passing through the thread catching plate, and the thread clamping plate and the thread catching plate clamp the cut thread, and the thread is cut.

[0027] As described above, the bird nest preventing device of the sewing machine provided by the present application can perform the two actions of catching the thread and cutting the thread in sequence, which can catch the thread at the start of sewing to ensure the stability of the thread hooking at the start of sewing, and cut the thread after the start of sewing to avoid the thread end being too long, thereby reducing the occurrence of the bird nest problem and improving the sewing quality.

[0028] The sewing machine provided by the present application comprises the bird nest preventing device described above, and has the same beneficial effects. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0030] Figure 1Figure showing the state of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention in the initial position;

[0031] Figure 2 Figure Figure 1 Assembly view of the remaining components after removing the fixing plate;

[0032] Figure 3 Figure Figure 1 Exploded view of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0033] Figure 4 Figure Figure 1 Structure view of the mounting seat of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0034] Figure 5 Figure Figure 4 Another view of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0035] Figure 6 Figure Figure 1 Structure view of the thread catching plate of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0036] Figure 7 Figure Figure 1 Structure view of the thread clamping plate of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0037] Figure 8 Figure Figure 1 Structure view of the thread cutting knife of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0038] Figure 9 Figure Figure 1 Structure view of the holding assembly of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0039] Figure 10 Figure Figure 1 Assembly view of the connecting rod and its accessories of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0040] Figure 11 Figure Figure 1 Structure view of the connecting pin of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention;

[0041] Figure 12 Figure showing the state of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention in the thread catching position;

[0042] Figure 13 Figure Figure 12 Assembly view of the remaining components after removing the fixing plate;

[0043] Figure 14 Figure showing the state of the bird nest prevention device of the sewing machine according to a specific embodiment of the present invention in the thread cutting position;

[0044] Figure 15 Figure Figure 14 Assembly view of the remaining components after removing the fixing plate;

[0045] Figure 16The state diagram of the bird nest preventing device of the sewing machine in a position of avoiding in a specific embodiment of the present application;

[0046] Figure 17 For Figure 16 The assembly diagram of the remaining components after removing the fixed plate;

[0047] Figure 18 The state diagram of the bird nest preventing device of the sewing machine in a position of avoiding in a specific embodiment of the present application;

[0048] Figure 19 For Figure 18 The assembly diagram of the remaining components after removing the fixed plate;

[0049] Figure 20 The partial structure diagram of the sewing machine in a specific embodiment of the present application.

[0050] The reference signs are as follows:

[0051] The fixed plate 1, the mounting seat 2, the thread catching plate 3, the thread clamping plate 4, the thread cutting knife 5, the elastic member 6, the holding assembly 7, the driving rod 8 and the connecting rod 9;

[0052] The longitudinal sliding groove 11;

[0053] The limiting sliding groove 21, the guide sliding groove 22, the U-shaped sliding groove 23, the guide sliding groove 24, the stop sliding groove 25, the stop step surface 26 and the limiting block 27;

[0054] The needle accommodating hole 30, the pushing protrusion 31, the pushing hook 32 and the connecting sliding block 33;

[0055] The necked portion 301;

[0056] The connecting sliding groove 331;

[0057] The connecting arm 41 and the sliding arm 42;

[0058] The reset spring piece 50, the limiting protrusion 51, the accommodating groove 52, the thread cutting guide pin 53 and the longitudinal sliding block 54;

[0059] The blocking end 501 and the elastic bent portion 502;

[0060] The vertical limiting plate 541;

[0061] The limiting spring piece 71 and the limiting sliding block 72;

[0062] The Z-shaped elastic portion 711;

[0063] The longitudinal limiting surface 721, the supporting protrusion 722, the side guide surface 723 and the limiting recess 724;

[0064] The waist-shaped sliding groove 90, the connecting pin 91, the sliding pin 92 and the limiting ring 93;

[0065] The pushing sliding block 911 and the stop flange 912. DETAILED DESCRIPTION

[0066] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0067] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0068] Please refer to Figures 1 to 19 , Figure 1 The state diagram of the bird nest prevention device of the sewing machine provided by an embodiment of the present application in the initial position; Figure 2 The Figure 1 The assembly diagram of the remaining components after removing the fixed plate;

[0069] Figure 3 The Figure 1 The exploded view of the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 4 The Figure 1 The structure diagram of the mounting seat in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 5 The Figure 4 Another view of the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 6 The Figure 1 The structure diagram of the thread catching plate in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 7 The Figure 1 The structure diagram of the thread clamping plate in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 8 The Figure 1 The structure diagram of the thread cutting knife in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 9 The Figure 1 The structure diagram of the holding assembly in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 10 The Figure 1 The assembly diagram of the connecting rod and its accessories in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 11 The Figure 1 The structure diagram of the connecting pin in the bird nest prevention device of the sewing machine provided by an embodiment of the present application; Figure 12 The state diagram of the bird nest prevention device of the sewing machine provided by an embodiment of the present application in the thread catching position; Figure 13 The Figure 12 The assembly diagram of the remaining components after removing the fixed plate; Figure 14 The state diagram of the bird nest prevention device of the sewing machine provided by an embodiment of the present application in the thread cutting position; Figure 15 The Figure 14 The assembly diagram of the remaining components after removing the fixed plate; Figure 16The state diagram of the bird nest prevention device of the sewing machine provided by the embodiment of the present application at the avoiding position; Figure 17 For Figure 16 The assembly diagram of the remaining components after removing the fixed plate; Figure 18 The state diagram of the bird nest prevention device of the sewing machine provided by the embodiment of the present application at the thread loosening position; Figure 19 For Figure 18 The assembly diagram of the remaining components after removing the fixed plate.

[0070] First of all, it needs to be pointed out that the longitudinal direction in the text refers to the length direction parallel to the mounting seat 2, the transverse direction in the text refers to the width direction parallel to the mounting seat 2, and the vertical direction in the text refers to the thickness direction parallel to the mounting seat 2. The front and back and other orientation words in the text are all based on the current view of the attached drawings, with the left side being the front and the right side being the back. Figure 1

[0071] The embodiment of the present application discloses a bird nest prevention device of a sewing machine, which can continuously perform thread grabbing and cutting actions by optimizing the structure, effectively reduces the occurrence of bird nests, and has high sewing quality.

[0072] The above-mentioned bird nest prevention device includes a thread cutting knife 5, a thread grabbing plate 3 and a thread clamping plate 4, all of which are plate-shaped structures, and the three are sequentially stacked from top to bottom, that is, the thread grabbing plate 3 is arranged between the thread cutting knife 5 and the thread clamping plate 4. The above-mentioned bird nest prevention device includes a mounting seat 2, and the thread cutting knife 5, the thread grabbing plate 3 and the thread clamping plate 4 are all slidably arranged on the mounting seat 2. The specific mounting method can be referred to the following content.

[0073] The thread cutting knife 5 includes a convex plate and a longitudinal sliding block 54, the convex plate is provided with a cutting edge at the protruding front end, which is used for cutting the surface thread. One side of the convex plate is slidably connected with the mounting seat 2, and the other side is provided with a retaining assembly 7. The longitudinal sliding block 54 is integrally arranged at the rear end of the convex plate, and the mounting seat 2 is correspondingly provided with a U-shaped sliding groove 23. The U-shaped sliding groove 23 and the longitudinal sliding block 54 are longitudinally slidably connected, which is used for guiding the longitudinal sliding of the thread cutting knife 5 relative to the mounting seat 2. In addition, one side of the bottom of the longitudinal sliding block 54 is integrally provided with a vertical limiting plate 541. In the vertical direction, one side of the vertical limiting plate 541 abuts against the bottom groove of the U-shaped sliding groove 23, and the other side abuts against the top pushing protrusion 31 of the thread grabbing plate 3, so as to limit the position of the thread cutting knife 5 in the vertical direction, avoiding the movement of the thread cutting knife 5 relative to the mounting seat 2 and the thread grabbing plate 3 in the vertical direction.

[0074] The front end of the thread grabbing plate 3 is provided with a needle containing hole 30. In the initial position, the front end of the thread grabbing plate 3 is arranged beyond the thread cutting knife 5 and the thread clamping plate 4, so that the thread cutting knife 5 and the thread clamping plate 4 are both away from the needle containing hole 30, ensuring that the needle containing hole 30 is located directly below the needle, so that the surface thread passes through the needle containing hole 30, and the thread grabbing position is separated from the thread loosening position, which is suitable for the sewing machine with small space below the needle plate.

[0075] ​The bird nest prevention device further comprises an elastic member 6 and a driving rod 8, the elastic member 6 is arranged between the thread catching plate 3 and the thread clamping plate 4 and is always kept in a stretched state, and specifically can be a tension spring. In the initial position, the elastic member 6 is in a stretched state, so that the thread catching plate 3 and the thread clamping plate 4 have a tendency of moving towards each other. Specifically, the thread catching plate 3 is provided with a waist-shaped hole penetrating through, the thread clamping plate 4 is also provided with a mounting hole penetrating through, the front end of the elastic member 6 is connected with the front end of the waist-shaped hole, and the rear end of the elastic member 6 is connected with the rear end of the mounting hole.

[0076] The driving rod 8 can be driven by a motor, and the motor is electrically connected with a controller, so that the controller controls the driving rod 8 to automatically act in a cycle.

[0077] When the driving rod 8 is released, the thread clamping plate 4 does not act due to the limitation of the mounting seat 2, the thread cutting knife 5 does not act due to the limitation of the retaining assembly 7, the elastic member 6 restores the elastic deformation, the thread catching plate 3 acts by the elastic force applied by the elastic member 6, the thread catching plate 3 drives the penetrating thread to act relative to the thread clamping plate 4 and the thread cutting knife 5, the thread catching plate 3 moves along the longitudinal direction from the initial position to the thread catching position, in the thread catching position, the front end of the thread catching plate 3 abuts against the front end of the thread clamping plate 4, the thread catching plate 3 and the thread clamping plate 4 clamp the thread, and the thread catching plate 3 clamps the thread. It should be noted that in the thread catching position, the thread catching plate 3 is no longer within the stroke range of the needle up and down movement.

[0078] After reaching the thread catching position, when the driving rod 8 is pulled, the driving rod 8 drives the thread catching plate 3 to continue to act, the thread cutting knife 5 continues to be in a state of inaction, the thread catching plate 3 drives the thread clamping plate 4 to act relative to the thread cutting knife 5, the thread catching plate 3 and the thread clamping plate 4 synchronously move along the longitudinal direction from the thread catching position to the thread cutting position, in the thread cutting position, the front end of the thread catching plate 3 abuts against the front end of the thread cutting knife 5, the thread cutting knife 5 cuts the thread penetrating through the thread catching plate 3 by means of the friction force generated by the relative movement, and the thread clamping plate 4 and the thread catching plate 3 keep clamping the cut thread, and the thread cutting knife 5 cuts the thread.

[0079] In summary, the bird nest prevention device of the sewing machine provided by the present application can perform the two actions of clamping the thread and cutting the thread in sequence, which can clamp the thread in the starting stage, ensure the stability of the starting thread hooking, cut the thread after the starting, and avoid the residual thread end being too long, so as to reduce the bird nest problem and improve the sewing quality.

[0080] The front end of the needle containing hole 30 is provided with a necked portion 301, when the thread is caught, the thread enters the necked portion 301, which can avoid the thread moving along the hole wall of the needle containing hole 30, so as to ensure that the thread cutting position is consistent every time, which has a positive significance for improving the sewing quality.

[0081] During the process of upward movement of the first needle after the first needle is sewn by the machine needle, the thread catching plate 3 moves to the thread catching position, and through clamping the first needle surface thread, the thread catching plate 3 can prevent the thread from being out of position after thread catching, effectively reducing the bird nest problem. After 2-3 needles are sewn by the machine needle, the thread catching plate 3 and the thread clamping plate 4 are synchronously moved from the thread catching position to the thread cutting position, so that the thread cutting position is arranged close to the needle plate hole, the residual thread end after cutting is shorter, and the thread end is easily wrapped into the subsequent sewing thread, so that the stitch is more beautiful and the sewing quality is better.

[0082] The above-mentioned anti-bird nest device further comprises a retaining assembly 7 fixed to the mounting seat 2, the retaining assembly 7 elastically abuts between the thread cutting knife 5 and the thread catching plate 3. Before the thread cutting position, the retaining assembly 7 limits the position of the thread cutting knife 5, and the thread cutting knife 5 remains stationary. At the thread cutting position, the retaining assembly 7 is released from the limitation, and the thread cutting knife 5 can be synchronously moved with the thread catching plate 3 and the thread clamping plate 4 to the avoiding position. That is, from the initial position to the thread cutting position, the thread cutting knife 5 remains stationary; from the thread cutting position to the avoiding position, the thread cutting knife 5 moves.

[0083] The retaining assembly 7 comprises a limiting spring sheet 71 and a limiting sliding block 72, one end of the limiting spring sheet 71 is fixed to the mounting seat 2 by means of a fastening screw, the other end of the limiting spring sheet 71 has a Z-shaped elastic part 711, the Z-shaped elastic part 711 is fixedly connected with the limiting sliding block 72, and the Z-shaped elastic part 711 provides support force for sliding of the limiting sliding block 72 at different positions. The mounting seat 2 is integrally provided with a limiting stop block 27, the rear side surface of the limiting sliding block 72 always abuts against the front side surface of the limiting stop block 27 in the longitudinal direction, so that the limiting sliding block 72 only moves in the transverse direction and does not move in the longitudinal direction. The limiting sliding block 72 can specifically be in an L shape.

[0084] The thread cutting knife 5 is integrally provided with a limiting protrusion 51 on the side close to the thread catching plate 3, and the limiting protrusion 51 is in a cylindrical shape. The back surface of the thread cutting knife 5 specifically refers to the side of the thread cutting knife 5 close to the thread catching plate 3. Correspondingly, the front end of the limiting sliding block 72 has a longitudinal limiting surface 721, before the thread cutting position, the longitudinal limiting surface 721 abuts against the limiting protrusion 51 in the longitudinal direction, at this time, the limiting sliding block 72 is clamped between the limiting protrusion 51 and the limiting stop block 27, and the limiting sliding block 72 does not move.

[0085] Of course, the structure of the retaining assembly 7 is not limited to this, for example, the retaining assembly 7 can also comprise a limiting rotating block hinged to the mounting seat 2, a torsional spring is sleeved on the rotating shaft of the limiting rotating block, two torsional arms of the torsional spring are respectively between the limiting rotating block and the mounting seat 2, by rotating the limiting rotating block, the limiting protrusion 51 and the limiting rotating block can also be in contact or separated in the longitudinal direction, and the purpose of the present application can still be achieved. Alternatively, other similar structures can also be used, and the position of the retaining assembly 7 is not specifically limited herein.

[0086] The side surface of the thread catching plate 3 is provided with a pushing protrusion 31, and the limiting sliding block 72 is provided with a supporting protrusion 722. When the thread catching plate 3 moves to the thread cutting position, the supporting protrusion 722 abuts against the side surface of the thread catching plate 3, the side surface of the thread catching plate 3 is a plane, the pushing protrusion 31 does not contact the supporting protrusion 722, the position of the limiting sliding block 72 is unchanged, and the thread cutting knife 5 is not in action. When the thread catching plate 3 moves to the thread cutting position, in the process of moving the thread catching plate 3 rearward along the longitudinal direction, the pushing protrusion 31 pushes the supporting protrusion 722 outward along the transverse direction, the Z-shaped elastic part 711 of the limiting spring sheet 71 is compressed, the limiting sliding block 72 moves relative to the thread cutting knife 5 along the transverse direction by overcoming the elastic force of the Z-shaped elastic part 711, the longitudinal limiting surface 721 is longitudinally staggered with the limiting protrusion 51, so that the limitation of the thread cutting knife 5 in the transverse direction is released, at this time, the limiting protrusion 51 abuts against the side guiding surface 723 of the limiting sliding block 72 along the transverse direction, and is used for guiding the thread cutting knife 5 to move along the longitudinal direction.

[0087] Specifically, the rear side surface of the pushing protrusion 31 is an inclined surface, and the end surface of the supporting protrusion 722 is a circular arc surface, so that the pushing protrusion 31 can push the limiting sliding block 72 to move uniformly along the transverse direction, and the limiting sliding block 72 is prevented from generating excessive impact vibration.

[0088] The side surface of the thread catching plate 3 is provided with a pushing hook 32, and the thread cutting knife 5 is provided with a containing groove 52. After reaching the thread cutting position, when the driving rod 8 is continuously pulled, the pushing hook 32 abuts against the containing groove 52, the thread catching plate 3 drives the thread clamping plate 4 and the thread cutting knife 5 to continuously move rearward along the longitudinal direction from the thread cutting position to a avoiding position, at the avoiding position, the thread cutting knife 5 and the thread catching plate 3 both abut against the mounting base 2 along the longitudinal direction, so that the thread cutting knife 5 and the thread catching plate 3 stop moving, at the same time, the limiting protrusion 51 slides into the limiting groove 724 arranged in the limiting sliding block 72 along the side guiding surface 723, the limiting protrusion 51 limits the movement of the limiting sliding block 72, so that the pushing protrusion 31 and the supporting protrusion 722 of the limiting sliding block 72 are kept in a separated state. The limiting groove 724 specifically refers to a circular arc groove arranged at the inner corner of the limiting sliding block 72. At the avoiding position, the bird nest preventing device can effectively avoid the thread cutting mechanism and avoid collision when sewing is completed.

[0089] Specifically, the mounting base 2 is provided with a stop step surface 26, at the avoiding position, the rear end surface of the thread cutting knife 5 abuts against the stop step surface 26, and the thread cutting knife 5 is limited to continuously act. The bottom of the mounting base 2 is provided with a guiding sliding groove 24, the thread catching plate 3 is slidably arranged in the guiding sliding groove 24, and is used for guiding the thread catching plate 3 to reciprocally slide along the longitudinal direction relative to the mounting base 2. The bottom of the mounting base 2 is further provided with a stop sliding groove 25, and correspondingly, one side of the thread catching plate 3 is integrally provided with a connecting sliding block 33, the connecting sliding block 33 is slidably arranged in the stop sliding groove 25, and is used for guiding the thread catching plate 3 to slide from the initial position to the avoiding position. At the avoiding position, the connecting sliding block 33 abuts against the side wall of the stop sliding groove 25 along the longitudinal direction, and the thread catching plate 3 is limited to continuously act. The guiding sliding groove 24 and the stop sliding groove 25 are communicated.

[0090] Mounting base 2 is also provided with guide groove 22, and wire cutter 5 is fixedly provided with wire cutting guide pin 53. The wire cutting guide pin 53 can be slidably inserted into the guide groove 22, so that the guide groove 22 guides the wire cutter 5 to slide longitudinally from the wire cutting position to the avoidance position.

[0091] The aforementioned bird nest prevention device also includes a connecting pin 91, which is connected to the drive rod 8. The specific installation method is detailed below. The top of the connecting pin 91 has a push-pull slider 911. The connecting slider 33 on the side of the wire gripping plate 3 has a connecting groove 331. The push-pull slider 911 can slide within the connecting groove 331 of the connecting slider 33. From the initial position to the avoidance position, the push-pull slider 911 is always located at the foremost end of the connecting groove 331. The side of the wire gripping plate 4 has an integrally integrated connecting arm 41.

[0092] In the initial position, the push slider 911 is not in contact with the connecting arm 41. When the wire gripping plate 3 slides longitudinally from the initial position to the wire gripping position, the push slider 911 and the connecting arm 41 come into contact longitudinally. In the wire cutting position and the avoidance position, the push slider 911 and the connecting arm 41 remain in contact.

[0093] Upon reaching the avoidance position, when the drive rod 8 is pulled further, the push slider 911 pushes the connecting arm 41 along the connecting groove 331. The clamping plate 4 moves relative to the gripping plate 3 and the wire cutter 5 with the connecting arm 41. The clamping plate 4 continues to move longitudinally from the avoidance position to the loosening position. The distance between the front end of the clamping plate 4 and the needle hole 30 of the gripping plate 3 increases, and the clamping plate 4 and the gripping plate 3 loosen the clamped thread.

[0094] Mounting base 2 is provided with a limiting slide groove 21. The side of the wire clamping plate 4 away from the connecting arm 41 is integrally provided with a sliding arm 42. The sliding arm 42 is hinged with a sliding pin 92. The sliding pin 92 is slidably engaged with the limiting slide groove 21 to guide the wire clamping plate 4 to slide longitudinally from the wire cutting position to the wire loosening position. When the wire clamping plate 4 slides to the wire loosening position, the sliding pin 92 abuts against the rear end of the limiting slide groove 21, and the push slider 911 abuts against the rear end of the connecting slide groove 331.

[0095] The bird nest preventing device further comprises a reset spring 50, the L-shaped structure of the reset spring 50 is fixed to the side of the thread cutter 5, and the end of the reset spring 50 close to the thread catching plate 3 is provided with a blocking end 501, and the blocking end 501 is provided with an elastic bending part 502 between the L-shaped structure. The reset spring 50 can keep the thread catching plate 3 and the thread cutter 5 in reliable contact in the avoiding position and the thread loosening position, and provide support force for the reciprocating movement of the thread cutter 5. It should be noted that the pushing force applied to the elastic bending part 502 by the pushing hook 32 from front to back is smaller than the pushing force applied by the pushing hook 32 from back to front, so that the pushing hook 32 is not easy to be separated from the thread cutter 5 during the forward movement of the pushing hook 32, and the thread cutter 5 can be smoothly returned to the initial position.

[0096] When the thread catching plate 3 moves from the thread catching position to the thread cutting position, the pushing hook 32 first contacts the blocking end 501, the pushing hook 32 pushes away the blocking end 501 into the accommodating groove 52 by overcoming the elastic force of the elastic bending part 502, so that the thread catching plate 3 drives the thread cutter 5 to move between the thread cutting position and the avoiding position, and the blocking end 501 of the reset spring 50 can prevent the pushing hook 32 from separating from the thread cutter 5. When resetting from the thread loosening position, the thread catching plate 4 is first driven by the driving rod 8 to move forward along the longitudinal direction from the thread loosening position to the avoiding position relative to the thread cutter 5 and the thread catching plate 3; then, the driving rod 8 drives the thread cutter 5, the thread catching plate 3 and the thread catching plate 4 to move forward along the longitudinal direction from the avoiding position to the thread cutting position; when the thread catching plate 3 moves from the thread cutting position to the thread catching position, the elastic bending part 502 of the reset spring 50 is elastically deformed to reversely push the blocking end 501, the pushing hook 32 separates from the accommodating groove 52, and the retaining assembly 7 restores the limitation of the movement of the thread cutter 5.

[0097] The bird nest preventing device further comprises a connecting rod 9, one end of the connecting rod 9 is hingedly connected with the sliding pin 92, and the other end of the connecting rod 9 is provided with a waist-shaped sliding groove 90, the waist-shaped sliding groove 90 is in sliding fit with the connecting pin 91, the relative movement distance of the thread catching plate 3 relative to the thread catching plate 4 has an upper limit value, so that the driving rod 8 is prevented from moving too fast in the resetting process, the relative distance between the thread catching plate 33 and the thread catching plate 4 at the elastic member 6 is prevented from being too long, and the elastic member 6 is prevented from being stretched too long to cause collision. It should be noted that from the thread cutting position to the avoiding position, the thread catching plate 3 and the thread catching plate 4 keep moving towards each other due to the elastic member 6, and the connecting pin 91 is arranged to keep a fixed distance between the two, so as to clamp the cut thread.

[0098] The bird nest preventing device further comprises a fixing plate 1, the mounting base 2 is fixed on the fixing plate 1, and the thread catching plate 3 and the clamping plate are arranged between the fixing plate 1 and the mounting base 2. The fixing plate 1 is provided with a longitudinal sliding groove 11, and a connecting pin 91 is slidably inserted into the longitudinal sliding groove 11 and used for guiding the connecting pin 91 to slide in the longitudinal direction. The connecting pin 91 is integrally provided with a stop flange 912, the stop flange 912 is in abutment with the groove of the longitudinal sliding groove 11, and is used for vertically limiting the connecting pin 91. A pushing sliding block 911 is integrally arranged on the top of the stop flange 912. The connecting pin 91 is sleeved with a limiting stop ring 93, and the driving rod 8 is arranged between the connecting rod 9 and the limiting stop ring 93. The tail of the connecting pin 91 is provided with an annular clamping groove, a clamping spring is arranged in the annular clamping groove, and the connecting rod 9 and the driving rod 8 are limited in the axial direction of the connecting pin 91.

[0099] The bird nest preventing device further comprises an air suction pipe arranged at the thread cutting position, the air suction pipe is connected with a negative pressure pump and used for sucking the cut thread end. The air suction pipe and the negative pressure pump are connected through a negative pressure pipe, and an electromagnetic valve can be arranged on the negative pressure pipe and used for controlling the air suction pipe to automatically suck the thread end.

[0100] The working principle of the bird nest preventing device is as follows:

[0101] In the initial position, the elastic member 6 is in a stretched state, the supporting protrusion 722 is in abutment with the side surface of the thread catching plate 3, the position of the limiting sliding block 72 is unchanged, and the thread cutting knife 5 is not in action;

[0102] When the driving rod 8 is released, the thread catching plate 4 and the thread cutting knife 5 are not in action, the thread catching plate 3 is driven to move along the longitudinal direction from the initial position to the thread catching position by the elastic force of the elastic member 6, the front end of the thread catching plate 3 is in abutment with the front end of the thread catching plate 4 in the thread catching position, the thread catching plate 3 and the thread catching plate 4 clamp the thread, and the pushing sliding block 911 is in abutment with the connecting arm 41 in the longitudinal direction;

[0103] When the driving rod 8 is pulled, the driving rod 8 drives the thread catching plate 3 to continue to act, the thread cutting knife 5 continues to be not in action, the thread catching plate 3 drives the thread catching plate 4 to continue to move along the longitudinal direction from the thread catching position to the thread cutting position, the pushing protrusion 31 pushes out the supporting protrusion 722 in the transverse direction, the limiting sliding block 72 moves in the transverse direction relative to the thread cutting knife 5 by overcoming the elastic force of the Z-shaped elastic part 711, and the hook 32 pushes away the blocking end 501 into the containing groove 52 by overcoming the elastic force of the elastic bending part 502; in the thread cutting position, the front end of the thread catching plate 3 is in abutment with the front end of the thread cutting knife 5, the thread cutting knife 5 cuts the thread passing through the thread catching plate 3, and the thread catching plate 4 and the thread catching plate 3 clamp the cut thread; at the same time, the longitudinal limiting surface 721 and the limiting protrusion 51 are in abutment in the longitudinal direction, and the limiting protrusion 51 is in abutment with the side guiding surface 723 of the limiting sliding block 72 in the transverse direction;

[0104] When the driving rod 8 is continuously pulled, the pushing hook 32 is abutted against the accommodating groove 52, the thread catching plate 3 drives the thread clamping plate 4 and the thread cutting knife 5 to continuously move along the longitudinal direction from the thread cutting position to the avoiding position, at the avoiding position, the thread cutting knife 5 and the thread catching plate 3 are both abutted against the mounting base 2 along the longitudinal direction, so that the thread cutting knife 5 and the thread catching plate 3 stop moving, at the same time, the limiting protrusion 51 slides along the side guide surface 723 into the limiting groove 724 arranged in the limiting sliding block 72, the pushing protrusion 31 and the supporting protrusion 722 of the limiting sliding block 72 are continuously kept in the separated state, the pushing sliding block 911 is located at the front end of the connecting sliding groove 331, the pushing sliding block 911 keeps in contact with the connecting arm 41, but the sliding pin 92 is not slid to the last end of the limiting sliding groove 21;

[0105] When the driving rod 8 is continuously pulled, the pushing hook 32 is abutted against the accommodating groove 52, the thread catching plate 3 drives the thread clamping plate 4 and the thread cutting knife 5 to continuously move along the longitudinal direction from the thread cutting position to the avoiding position, at the avoiding position, the thread cutting knife 5 and the thread catching plate 3 are both abutted against the mounting base 2 along the longitudinal direction, so that the thread cutting knife 5 and the thread catching plate 3 stop moving, at the same time, the limiting protrusion 51 slides along the side guide surface 723 into the limiting groove 724 arranged in the limiting sliding block 72, the pushing protrusion 31 and the supporting protrusion 722 of the limiting sliding block 72 are continuously kept in the separated state, the pushing sliding block 911 is located at the front end of the connecting sliding groove 331, the pushing sliding block 911 keeps in contact with the connecting arm 41, but the sliding pin 92 is not slid to the last end of the limiting sliding groove 21;

[0106] When the driving rod 8 is continuously pulled, the pushing hook 32 is abutted against the accommodating groove 52, the thread catching plate 3 drives the thread clamping plate 4 and the thread cutting knife 5 to continuously move along the longitudinal direction from the thread cutting position to the avoiding position, at the avoiding position, the thread cutting knife 5 and the thread catching plate 3 are both abutted against the mounting base 2 along the longitudinal direction, so that the thread cutting knife 5 and the thread catching plate 3 stop moving, at the same time, the limiting protrusion 51 slides along the side guide surface 723 into the limiting groove 724 arranged in the limiting sliding block 72, the pushing protrusion 31 and the supporting protrusion 722 of the limiting sliding block 72 are continuously kept in the separated state, the pushing sliding block 911 is located at the front end of the connecting sliding groove 331, the pushing sliding block 911 keeps in contact with the connecting arm 41, but the sliding pin 92 is not slid to the last end of the limiting sliding groove 21;

[0107] Therefore, the driving rod 8 can drive each component to perform different actions in one reciprocating motion cycle, and continuously realize five actions of thread catching, thread cutting, avoiding, thread loosening and resetting.

[0108] Please refer to Figure 20 , Figure 20 for the partial structure diagram of the sewing machine provided by the embodiment of the present application.

[0109] The embodiment of the present application further discloses a sewing machine comprising the above bird nest preventing device, and has the same beneficial effects.

[0110] The sewing machine and the bird nest preventing device thereof provided by the present application are described in detail above, and the principles and implementation manners of the present application are described by using specific examples in this paper. The above examples are only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In summary, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A nest prevention device for a sewing machine, comprising: It comprises a cutting thread knife (5), a thread catching plate (3) and a thread clamping plate (4) which are slidably stacked from top to bottom, further comprises an elastic member (6) arranged between the thread catching plate (3) and the thread clamping plate (4), a mounting base (2), a driving rod (8) connected with the thread catching plate (3) and a connecting pin (91) connected with the driving rod (8); When the driving rod (8) is released, the thread catching plate (3) drives the thread passing through it to move along the longitudinal direction from the initial position to the thread catching position relative to the thread clamping plate (4) and the cutting thread knife (5) respectively, and the thread catching plate (3) and the thread clamping plate (4) clamp the thread; When the driving rod (8) is pulled, the thread clamping plate (4) drives the thread catching plate (3) to continue to move along the longitudinal direction from the thread catching position to the thread cutting position relative to the cutting thread knife (5), and the cutting thread knife (5) cuts the thread passing through the thread catching plate (3), and the thread clamping plate (4) and the thread catching plate (3) keep clamping the cut thread; The side of the thread catching plate (3) is provided with a pushing hook (32), and the cutting thread knife (5) is provided with a containing groove (52); when the driving rod (8) is continuously pulled, the pushing hook (32) abuts against the containing groove (52), and the thread clamping plate (4) drives the thread catching plate (3) and the cutting thread knife (5) to continue to move along the longitudinal direction from the thread cutting position to the avoiding position respectively, and the cutting thread knife (5) and the thread catching plate (3) both abut against the mounting base (2) along the longitudinal direction; The top end of the connecting pin (91) is provided with a pushing sliding block (911), and the side of the thread catching plate (3) is integrally provided with a connecting sliding block (33), and the pushing sliding block (911) is slidably arranged in the connecting sliding groove (331) of the connecting sliding block (33); the side of the thread clamping plate (4) is integrally provided with a connecting arm (41); When the thread catching plate (3) slides along the longitudinal direction from the initial position to the thread catching position, the pushing sliding block (911) abuts against the connecting arm (41) along the longitudinal direction; When the driving rod (8) is continuously pulled, the pushing sliding block (911) of the connecting pin (91) pushes the connecting arm (41) along the connecting sliding groove (331), and the thread clamping plate (4) continues to move along the longitudinal direction from the avoiding position to the thread releasing position relative to the thread catching plate (3) and the cutting thread knife (5) respectively, and the thread clamping plate (4) and the thread catching plate (3) release the clamped thread.

2. The nest prevention device for a sewing machine according to claim 1, characterized by Further comprising: A retaining assembly (7) which is fixed to the mounting base (2) and elastically abuts between the cutting thread knife (5) and the thread catching plate (3) to limit the cutting thread knife (5) from keeping still before the thread cutting position.

3. The nest prevention device for a sewing machine according to claim 2, characterized by The side of the cutting thread knife (5) close to the thread catching plate (3) is provided with a limiting protrusion (51), and the retaining assembly (7) comprises: A limiting spring sheet (71) which is fixed to the mounting base (2) at one end and has a Z-shaped elastic part (711) at the other end; A limiting slider (72) is fixedly connected with the Z-shaped elastic part (711) and longitudinally abuts against a limiting block (27) provided on the mounting base (2); the limiting slider (72) has a longitudinal limiting surface (721), which longitudinally abuts against the limiting protrusion (51) before the thread cutting position.

4. The nest prevention device for a sewing machine according to claim 3, characterized by The side of the thread catching plate (3) has a pushing protrusion (31), and the limiting slider (72) has a supporting protrusion (722); when the thread catching plate (3) moves to the thread cutting position, the supporting protrusion (722) abuts against the side of the thread catching plate (3); when the thread catching plate (3) moves to the thread cutting position, the pushing protrusion (31) pushes the supporting protrusion (722) outward in the transverse direction, the longitudinal limiting surface (721) is longitudinally staggered with the limiting protrusion (51), and the limiting protrusion (51) abuts against the side guiding surface (723) of the limiting slider (72) in the transverse direction.

5. The nest prevention device for a sewing machine according to claim 4, characterized in that, The limiting protrusion (51) slides along the side guiding surface (723) into a limiting groove (724) provided on the limiting slider (72).

6. The nest prevention device for a sewing machine according to claim 1, wherein The mounting base (2) is provided with a limiting sliding groove (21), and the thread clamping plate (4) is integrally provided with a sliding arm (42) on the side away from the connecting arm (41); the sliding arm (42) is hingedly connected with a sliding pin (92) which is in sliding cooperation with the limiting sliding groove (21) and is used to guide the thread clamping plate (4) to slide in the longitudinal direction from the thread cutting position to the thread loosening position; when the thread clamping plate (4) slides to the thread loosening position, the sliding pin (92) abuts against the last end of the limiting sliding groove (21), and the pushing slider (911) abuts against the last end of the connecting sliding groove (331).

7. The nest prevention device for a sewing machine according to claim 6, wherein Further comprising a reset spring piece (50) having a blocking end (501) at one end fixed to the thread cutting knife (5) and at the other end; when the thread catching plate (3) moves from the thread cutting position to the thread cutting position, the pushing hook (32) pushes away the blocking end (501) into the containing groove (52), and the thread catching plate (3) drives the thread cutting knife (5) to move between the thread cutting position and the avoiding position; when the thread catching plate (3) moves from the thread cutting position to the thread cutting position, the reset spring piece (50) is deformed to push away the blocking end (501), and the pushing hook (32) is separated from the containing groove (52).

8. The nest prevention device for a sewing machine according to claim 6, wherein Further comprising a connecting rod (9) having one end hingedly connected with the sliding pin (92) and the other end provided with a waist-shaped sliding groove (90); the waist-shaped sliding groove (90) is in sliding cooperation with the connecting pin (91), and the connecting pin (91) is provided with a limiting stop ring (93) for axially limiting the connecting rod (9).

9. A sewing machine characterized by comprising: The bird nest preventing device comprises the device according to any one of claims 1 to 8. The bird nest preventing device comprises the device according to any one of claims 1 to 8.

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