CN107574588B

CN107574588B - Presser foot assembly of sewing machine

Info

Publication number: CN107574588B
Application number: CN201710864032.XA
Authority: CN
Inventors: 张敬业
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-10-29
Filing date: 2015-10-29
Publication date: 2020-01-21
Anticipated expiration: 2035-10-29
Also published as: CN107574588A; CN105297295B; CN105297295A

Abstract

The invention provides a presser foot component of a sewing machine, which comprises a presser foot with a presser foot plate, wherein the presser foot plate is provided with a needle hole for a needle to pass through up and down; after the presser foot is put down, the thread head of the sewing thread penetrating in the needle is clamped in the presser foot component of the sewing machine; when sewing, the sewing thread is fixed on the sewing product, and the sewing product drives the sewing thread to move forward so that the sewing thread is contacted with the heating wire. The sewing thread end can be automatically trimmed, an operator does not need to manually trim the sewing thread end on the surface of a sewing product after sewing is finished, and therefore working efficiency is greatly improved.

Description

Presser foot assembly of sewing machine

The application is a divisional application, and the application number of the parent application is 201510734353.9, the application date is 2015, 10 and 29, and the invention is named as a sewing machine presser foot assembly.

Technical Field

The invention relates to the field of sewing machinery, in particular to a sewing machine presser foot component capable of clamping a sewing thread head and automatically cutting the sewing thread head.

Background

A sewing machine is a machine that uses one or more sewing threads to form one or more stitches in a fabric, thereby interweaving or stitching together one or more layers of the fabric. The sewing machine mainly comprises four parts, namely a machine head, a machine base, a transmission mechanism and accessories; the machine head is the main part of the sewing machine and comprises a needling mechanism, a thread hooking mechanism, a thread picking mechanism, a feeding mechanism, a pressing mechanism and the like, and the movement of the mechanisms is reasonably matched and the mechanisms work circularly, so that the cloth is sewn. The pressing mechanism is mainly used for pressing the cloth on the cloth feeding tooth through the presser foot component so as to move the cloth during sewing, thereby ensuring the flatness and stability of the cloth at the needle falling position of the sewing machine needle.

With the continuous development of the sewing machine technology and at night, some sewing machines with automatic thread cutting functions are also available in the market, for example, the chinese patent application No. 201010576959.1 discloses a thread cutting mechanism in the sewing machine, and for example, the chinese patent application No. 201210204131.2 discloses an automatic thread cutting device of the sewing machine. However, in both the sewing machine having the automatic thread trimming function and the sewing machine requiring manual thread trimming, the thread end of the sewing thread inserted in the needle may be extremely unstable after the thread trimming is completed. After the sewing thread is cut off, the thread end of the sewing thread on the machine needle is very easy to be drawn out when the sewing is carried out again if the thread end is too short, therefore, the sewing machine needs an operator to press the thread end on the machine needle when the sewing is carried out again in the actual production and use process, the workload of the operator can be increased, the thread end is remained on the surface of a sewing product after the sewing is finished, the thread end needs to be trimmed by the operator, and the production efficiency is reduced. Or if the thread end of the sewing thread on the machine needle is too short, two or three needles or even longer distance can not be fed easily during secondary sewing, and the needle needs to be supplemented after sewing is finished, so that the workload of operators is greatly increased, and the production efficiency is reduced. Or, after the sewing thread is cut, if the sewing thread end on the needle is in a free state by the thread sweeping device, the sewing thread end on the needle is disorderly wound on the sewing thread stitch on the sewing product when sewing again, so that the stitch of the sewing product is very unattractive, and the quality and the qualification rate of the sewing product are reduced.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a presser foot assembly of a sewing machine capable of automatically cutting off a sewing thread end.

In order to achieve the purpose, the invention provides a presser foot component of a sewing machine, which comprises a presser foot with a presser foot plate, wherein the presser foot plate is provided with a needle hole for a needle to penetrate through, the presser foot plate is also internally provided with a trimming groove which is positioned at the front end of the needle hole and is communicated with the needle hole, a heating wire is arranged in the presser foot plate in a penetrating way, and part of the heating wire is exposed out of the trimming groove and positioned in front of the needle; after the presser foot is put down, the thread head of the sewing thread penetrating in the needle is clamped in the presser foot component of the sewing machine; when sewing, the sewing thread is fixed on the sewing product, and the sewing product drives the sewing thread to move forward so that the sewing thread is contacted with the heating wire.

Furthermore, a plurality of line dividing parts located at the front end of the pinhole are arranged on the foot pressing plate, the line shearing groove is formed between every two adjacent line dividing parts, and the heating wire is arranged in the line dividing parts in a penetrating mode.

Preferably, an insulating tube fixed in the branching part is arranged between the branching part and the heating wire, and the insulating tube is used for isolating the heating wire from the presser foot.

Preferably, the line-dividing portion has a V-shape, and a tip located at a rear side of the line-dividing portion faces the needle.

Furthermore, the presser foot further comprises two presser foot arms arranged on the upper end face of the presser foot plate, a connecting block is fixed on the outer surface of each presser foot arm, a power line jack is arranged in each connecting block, and the two ends of the heating wire and the end part of the power line are arranged in the power line jacks and are fixed and conducted through fasteners.

The thread clamping device comprises a presser foot seat and a thread clamping piece hinged to the presser foot seat, wherein the presser foot is installed at the lower end of the presser foot seat, a first air suction channel, a first air suction opening and a thread clamping part are arranged in the presser foot seat, the first air suction opening is positioned at the end part of the first air suction channel and faces towards a machine needle, and the thread clamping piece is positioned in the first air suction channel and can rotate up and down; when the presser foot is lifted, the thread clamping sheet is turned downwards, and the thread end of the sewing thread is sucked into the first air suction channel at the first air suction opening; when the presser foot is put down, the thread clamping sheet is turned upwards, and the sewing thread head is clamped between the thread clamping sheet and the thread clamping part.

Preferably, the sewing machine further comprises an air suction pipe and a presser bar sleeve which are fixed in the sewing machine shell, and a presser bar which can be vertically moved and penetrates through the presser bar sleeve, the presser bar seat is installed at the lower end of the presser bar, a second air suction channel communicated with the first air suction channel is arranged in the presser bar, a second air suction opening communicated with the second air suction channel is arranged on the outer wall of the presser bar, the presser bar is further provided with a covering part above the second air suction opening, a third air suction channel is arranged in the air suction pipe, the air suction pipe is connected with external air suction equipment, and a third air suction opening communicated with the third air suction channel is arranged on the outer wall of the presser bar sleeve; when the pressure foot rod moves upwards, the second air suction opening is communicated with the third air suction opening; when the presser bar moves downwards, the second air suction opening and the third air suction opening are blocked by the blocking part.

The presser foot is arranged at the lower end of the presser foot seat, a first air suction channel, a first air suction opening and a yarn clamping part are arranged in the presser foot, the first air suction opening is positioned at the end part of the first air suction channel and faces the needle, the yarn clamping part is positioned in the first air suction channel, and the yarn clamping part can rotate up and down; when the presser foot is lifted, the thread clamping sheet is turned downwards, and the thread end of the sewing thread is sucked into the first air suction channel at the first air suction opening; when the presser foot is put down, the thread clamping sheet is turned upwards, and the sewing thread head is clamped between the thread clamping sheet and the thread clamping part.

Preferably, the sewing machine further comprises a presser foot rod sleeve fixed in the sewing machine shell, a presser foot rod penetrating in the presser foot rod sleeve in a vertically movable mode, and an air suction pipe provided with a third air suction channel, wherein the presser foot seat is installed at the lower end of the presser foot rod, the air suction pipe is connected with the presser foot to form an integral component, the air suction pipe is connected with external air suction equipment, and the third air suction channel is connected with the first air suction channel.

The sewing machine further comprises a presser foot rod sleeve fixed in the sewing machine shell, a presser foot rod capable of penetrating in the presser foot rod sleeve in a vertically movable mode, a striker capable of moving vertically, a stop block fixed at the lower end of the presser foot rod sleeve and a bushing fixed on the presser foot rod, wherein the presser foot seat is installed at the lower end of the presser foot rod, a first through hole extending vertically is formed in the bushing, a second through hole extending vertically and communicated with the first air suction channel is formed in the presser foot seat, the striker penetrates through the first through hole and the second through hole in sequence, and the upper end of the striker is arranged above the bushing; when the presser foot is put down, the distance between the upper end of the firing pin and the lower end of the stop block is smaller than the stroke of the presser foot rod moving upwards when the presser foot is lifted.

As described above, the presser foot assembly of the sewing machine according to the present invention has the following advantages:

the sewing thread end can be automatically trimmed, an operator does not need to manually trim the sewing thread end on the surface of a sewing product after sewing is finished, and therefore working efficiency is greatly improved.

Drawings

Fig. 1 is a schematic structural diagram according to an embodiment of the present invention.

Fig. 2 is a top view of fig. 1.

Fig. 3 is a half-sectional view of fig. 1 with the presser foot raised.

Fig. 4 is a half sectional view of fig. 1 with the presser foot in a lowered condition.

Fig. 5 is a schematic view of the connection between the presser foot seat and the presser foot in fig. 1.

Fig. 6 is a schematic structural diagram of the pressure foot seat in fig. 1.

Fig. 7 is a side view of fig. 6.

Fig. 8 is a top view of fig. 6.

Fig. 9 is a half sectional view of fig. 7.

Fig. 10 is a schematic structural view of the presser foot of the present invention.

Fig. 11 is a bottom view of fig. 10.

Fig. 12 is a side view of fig. 10.

Fig. 13 is a schematic structural diagram of another embodiment of the present invention.

Fig. 14 is a schematic structural diagram of the presser foot seat in fig. 13.

Fig. 15 is a front view of fig. 14.

Fig. 16 is a side view of fig. 14.

Fig. 17 is a top view of fig. 14.

Fig. 18 is a half-sectional view of fig. 16.

Fig. 19 is another embodiment of a presser foot in the present application.

Fig. 20 is a top view of fig. 19.

Fig. 21 is a sectional view taken along line a-a of fig. 20.

Fig. 22 shows another embodiment of the presser foot to presser foot mount connection arrangement of the present application. Fig. 23 is a schematic view of the structure of the presser foot of fig. 22.

Fig. 24 shows another embodiment of the presser foot and presser foot rest of the present application.

Description of the element reference numerals

1 case

2 presser foot rod

21 second suction channel

22 second air inlet

23 damming part

3 presser foot seat

31 first air suction channel

32 first air suction opening

33 thread clamping part

34 second through hole

35 presser bar mounting part

351 presser bar mounting hole

352 locking part

353 installation gap

36 presser foot mounting part

361 first connecting hole

362 second connecting hole

363 third connecting hole

364 cleat attaching part

37 presser foot mounting arm

4 presser foot

41 presser foot plate

42 presser arm

43 pinhole

44 branching part

45 heating wire

46 trimming groove

47 connecting block

471 power cord jack

48 presser foot seat connecting part

5 wire clamping sheet

6 air suction pipe

61 third suction channel

7 presser foot rod sleeve

71 third air suction inlet

8 firing pin

81 flange part

9 stop dog

10 liner

101 first via hole

11 first return spring

12 second return spring

13 magnet

14 screw

15 pin shaft

16 machine needle

17 Sewing thread

171 sewing thread end

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, proportions, and dimensions shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, which is defined by the claims, but rather by the claims. In addition, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description only and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship thereof may be made without substantial technical changes and modifications.

In the following examples, the directions are defined as follows: the length direction of the presser foot 4 is defined as the front-back direction, the width direction of the presser foot 4 is defined as the left-right direction, and the thickness direction of the presser foot 4 is defined as the up-down direction; alternatively, when viewing fig. 3 and 4, the upper side of the paper surface is the upward direction, the lower side of the paper surface is the downward direction, the left side of the paper surface is the forward direction, the right side of the paper surface is the backward direction, the front surface of the paper surface is the left direction, and the back surface of the paper surface is the right direction.

The application provides a presser foot assembly of sewing machine for hold the sewing thread end of thread through induced drafting when lifting up presser foot 4, and fix the sewing thread end of thread when putting down presser foot 4.

As shown in fig. 1 to 4, in the first embodiment of the presser foot assembly, the presser foot assembly of the sewing machine includes a presser foot bar 2 capable of moving up and down, a presser foot seat 3 installed at a lower end of the presser foot bar 2, and a presser foot 4 installed at a lower end of the presser foot seat 3, a first air suction passage 31 is opened in the presser foot seat 3, a rear end of the first air suction passage 31 is a first air suction port 32 facing a needle 16 of the sewing machine, the first air suction port 32 is located at a front side of the needle 16 of the sewing machine, a thread clamping piece 5 located in the first air suction passage 31 is provided in the presser foot seat 3, a front end of the thread clamping piece 5 is hinged to the presser foot seat 3, so that a rear end of the thread clamping piece 5 can rotate up and down, and a thread clamping part 33 located in the first air suction passage 31 and located at a side of the first air suction port 32 is further provided on the presser.

In the sewing process of the sewing machine, the presser foot 4 is in a laid-down state. After the sewing is finished and the sewing thread 17 is cut, and the presser foot 4 is lifted, at this time, as shown in fig. 3, the thread tension sheet 5 is in a state of being turned downward and the first air suction opening 32 is in a state of being opened; the sewing thread end 171 formed after the cutting of the sewing thread 17 is sucked into the first suction passage 31 at the first suction port 32 by the suction of the external suction device. Then, the presser foot 4 is put down, as shown in fig. 4, the rear end of the thread clamping piece 5 is turned upwards, the first air suction opening 32 is closed by the thread clamping piece 5, and the sewing thread end 171 sucked into the first air suction channel 31 is clamped between the thread clamping piece 5 and the thread clamping part 33, so that the sewing thread end 171 is fixed, and the phenomena that the stitch of the sewing product is not beautiful, an operator needs to press the thread end or repair a needle and the like due to the fact that the sewing thread end 171 is drawn out due to being too short or the sewing thread end 171 is in a free state when the sewing is carried out again in the prior art are avoided, and further the working efficiency and the quality of the sewing product are improved. Preferably, the external air draft equipment is an exhaust fan and the like.

Further, since the installation space of the sewing machine at the presser foot 4 and the presser foot seat 3 is very limited, in order to facilitate the connection of the presser foot assembly with the external air draft device, in the present application, as shown in fig. 1 and 3, the presser foot assembly further includes an air draft tube 6 and a presser foot bar sleeve 7 fixed in the sewing machine housing 1. The utility model discloses a pressure foot bar, including pressure foot bar sleeve 7, pressure foot bar 2, first air suction channel 31, second air suction channel 21, the outer wall of pressure foot bar 2, the shutoff portion that extends around this shutoff portion and the outer wall of pressure foot bar 2 that is located second air suction channel 22 form pressure foot bar 2 jointly, should cover the portion 23 and be located the top of second air suction channel 22, set up third air suction channel 61 in aspiration channel 6, and aspiration channel 6 is connected with external air extraction equipment, set up the third inlet scoop 71 that is linked together with third air suction channel 61 on the outer wall of pressure foot bar sleeve 7, set up in pressure foot bar 2 with the second air suction channel 21 that first air suction channel 31 is linked together, set up on the outer wall of pressure foot bar sleeve 7 and induced draft the second inlet scoop 22 that is linked together with second air suction channel 21, pressure foot bar 2 is equipped with the shutoff portion that extends around the upper end of second air suction channel 21. When the presser bar 2 moves upwards, the second air suction opening 22 is communicated with the third air suction opening 71, so that the first air suction opening 32, the first air suction channel 31, the second air suction channel 21, the second air suction opening 22, the third air suction opening 71 and the third air suction channel 61 are sequentially communicated, and a suction force is formed at the first air suction opening 32 under the action of an external air suction device; when the presser bar 2 moves down, the second air suction opening 22 and the third air suction opening 71 are blocked by the blocking portion 23, so that there is no suction force at the first air suction opening 32.

Further, when the presser bar 2 moves upwards, the rear end of the wire clamping piece 5 turns downwards; when the presser bar 2 moves down, the rear end of the thread clamping piece 5 turns upwards, and the preferred embodiment for realizing the linkage action is as follows: as shown in fig. 3 and 7, the pneumatic sewing machine further comprises a striker 8 capable of moving up and down, a stopper 9 is fixed at the lower end of the presser bar sleeve 7, a bushing 10 is fixed on the presser bar 2, a first through hole 101 extending up and down is formed in the bushing 10, a second through hole 34 extending up and down and communicated with the first air suction channel 31 is formed in the presser bar seat 3, the lower end of the striker 8 is sequentially inserted into the first through hole 101 and the second through hole 34 and can be contacted with the upper end face of the thread clamping piece 5 positioned in the first air suction channel 31, and the upper end of the striker 8 is positioned above the bushing 10; when the presser foot 4 is in a laid-down state, the distance between the upper end of the striker 8 and the lower end of the stopper 9 is smaller than the stroke of upward movement of the presser foot rod 2 when the presser foot 4 is lifted. The upper end of the striker 8 is provided with a flange portion 81, and the striker 8 is sleeved with a first return spring 11 positioned between the flange portion 81 and the bush 10. A magnet fixing groove communicated with the first air suction channel 31 is formed in the presser foot seat 3, a magnet 13 located above the thread clamping piece 5 is arranged in the magnet fixing groove, the magnet 13 is fixed on the inner surface of the presser foot seat 3 through a screw 14, a hole for allowing the firing pin 8 to pass through is formed in the magnet 13, a second return spring 12 located below the thread clamping piece 5 and located in the first air suction channel 31 is fixed in the presser foot 4, and the second return spring 12 axially extends in the up-down direction.

During sewing, the presser foot 4 is in a lowered state, and at this time, the thread clamping piece 5 is attracted by the magnet 13. When the sewing is finished and the presser foot 4 is lifted, the presser foot rod 2 moves upwards, the presser foot rod 2 drives the presser foot seat 3, the thread clamping sheet 5, the presser foot 4, the bush 10 and the firing pin 8 to move upwards together, since the distance L between the upper end of the striker 8 and the stopper 9 is smaller than the upward movement stroke of the presser bar 2, the presser bar 2 continues to move upward for a certain distance after the upper end of the striker 8 contacts the stopper 9, in the process, because the stop 9 limits the striker 8 to move upwards with the presser bar 2, and the presser foot seat 3 and the presser foot 4 move upwards with the presser bar 2, the lower end of the striker 8 moves downwards relative to the presser foot seat 3 and the presser foot 4, thereby contacting with the upper end surface of the thread clamping piece 5, separating the thread clamping piece 5 from the magnet 13, and turning the rear end of the thread clamping piece 5 downwards, to open the first suction port 32, at which time the first and second return springs 11 and 12 are both in a compressed state. When the presser foot 4 is sewn again and put down, the presser bar 2 moves downwards, the presser bar 2 drives the presser foot seat 3, the thread clamping piece 5, the presser foot 4, the bush 10 and the striker 8 to move downwards together, after the upper end of the striker 8 is separated from the stop block 9, the striker 8 moves upwards relative to the bush 10 and the presser foot seat 3 due to the elastic force of the first return spring 11, the lower end of the striker 8 is separated from the upper end face of the thread clamping piece 5, and the thread clamping piece 5 rotates upwards due to the adsorption force of the magnet 13 and the elastic force of the second return spring 12 until the rear end of the thread clamping piece 5 abuts against the thread clamping part 33 of the presser foot seat 3.

Further, the connecting structure of the lower end of the presser bar 2 and the presser foot seat 3 is as follows: as shown in fig. 1, 5 and 8, a presser bar mounting portion 35 is provided at an upper end of the presser base 3, a presser bar mounting hole 351 for allowing a lower end of the presser bar 2 to extend into is provided on the presser bar mounting portion 35, two locking portions 352 protruding in a radial direction and provided opposite to each other and a mounting gap 353 between the two locking portions 352 are further provided on the presser bar mounting portion 35, the mounting gap 353 is communicated with the presser bar mounting hole 351, and holes for allowing fasteners such as screws 14 to pass are provided on the two locking portions 352. The lower end of the pressure foot rod 2 is embedded into the pressure foot rod mounting hole 351 of the pressure foot seat 3, and the mounting gap 353 is expanded, so that the lower end of the pressure foot rod 2 is conveniently embedded; the screws 14 are then inserted through the holes of the two locking portions 352 to lock the two locking portions 352, thereby securing the presser foot base 3 to the lower end of the presser bar 2.

In addition, the presser foot seat 3 and the presser foot 4 may be of an integral structure, and as shown in fig. 24, they are connected as an integral member. Of course, the presser foot seat 3 and the presser foot 4 may be of a separate structure, and in this case, the connecting structure of the presser foot seat 3 and the presser foot 4 is: as shown in fig. 5, 6 and 10, the lower end of the presser foot base 3 is provided with a presser foot mounting portion 36, the presser foot 4 comprises a presser foot plate 41 extending back and forth and two presser foot arms 42 respectively arranged at the left and right sides of the front end of the presser foot plate 41, the presser foot mounting portion 36 of the presser foot base 3 is positioned between the two presser foot arms 42 of the presser foot 4, and the front and back sides of the presser foot mounting portion 36 are aligned with the front and back sides of the presser foot arms 42; both sides all are equipped with two and control the first connecting hole 361 that link up around presser foot installation department 36, and the position of the first connecting hole 361 that is located the rear side in upper and lower direction will be less than the first connecting hole 361 that is located the front side, and two and first connecting hole 361 are seted up on two presser foot arms 42 and are controlled the second connecting hole 362 of aligning the setting, wear to be equipped with round pin axle 15 in first connecting hole 361 and the second connecting hole 362 to be connected presser foot installation department 36 of presser foot seat 3 with the presser foot arm 42 of presser foot 4. In addition, the second connecting hole 362 at the upper end of the front side of the presser arm 42 is a long hole, and the pin 15 inserted into the second connecting hole 362 can slightly move up and down, thereby controlling the fine movement of the presser foot 4 relative to the presser foot base 3 in the up and down direction.

Further, the connection structure of the presser foot seat 3 and the thread clamping piece 5 is as follows: as shown in fig. 3 and 6, two thread clamping piece mounting portions 364 extending forward and backward are provided at the front end of the presser foot mounting portion 36 away from the needle 16, third connecting holes 363 penetrating left and right are provided on both the two thread clamping piece mounting portions 364, the front end of the thread clamping piece 5 away from the first air suction opening 32 is located between the two thread clamping piece mounting portions 364 and hinged with the thread clamping piece mounting portions 364 through a rotating shaft, and the left and right ends of the rotating shaft are inserted into the two third connecting holes 363.

Preferably, the first air suction passage 31 is opened in the presser foot mounting part 36 of the presser foot base 3, and the first air suction passage 31 is formed by the upper surface of the presser foot plate 41, the lower surface of the presser foot mounting part 36, the rear surface of the front wall of the presser foot mounting part 36 and the inner surfaces of the two presser foot arms 42; the rear wall of the presser foot mounting part 36 is suspended above the presser foot plate 41, so that a first air suction opening 32 is formed between the lower surface of the rear wall of the presser foot mounting part 36 and the upper surface of the presser foot plate 41, and the front end of the first air suction passage 31 is blocked by the front wall of the presser foot mounting part 36. The front wall of the presser foot mounting part 36 is located between the two thread tension sheet mounting parts 364, and a first connecting hole 361 located above the front side of the presser foot mounting part 36 is opened in the front wall of the presser foot mounting part 36. In order to ensure that the front wall and the rear wall of the presser foot mounting portion 36 are processed with a sufficient amount in the front-rear direction to process the two first connection holes 361, the lower end of the first air suction passage 31 is disposed obliquely rearward and downward, so that the thicknesses of the front wall and the rear wall of the presser foot mounting portion 36 in the front-rear direction are relatively increased to ensure smooth mounting of the presser foot mounting portion 36 and the presser foot arm 42, and the length of the presser foot plate 41 in the front-rear direction is relatively decreased. In addition, the second air suction passage 21 of the presser bar 2 extends up and down, the lower end thereof extends down to the upper end of the first air suction passage 31, and the third air suction passage 61 of the air suction pipe 6 extends back and forth.

Preferably, the lower surface of the thread clamping part 33 of the presser foot base 3 and the upper surface of the rear end of the thread clamping piece 5 are thread clamping surfaces in contact with the sewing thread end 171, and both thread clamping surfaces are roughened to form rough surfaces, so that the friction force between the thread clamping part 33 and the sewing thread end 171 and between the thread clamping piece 5 and the sewing thread end 171 is increased during thread clamping, and the sewing thread end 171 is clamped more firmly.

Further, the presser foot assembly of the present invention can automatically cut off the held sewing thread end 171. As shown in fig. 11 and 12, the presser foot plate 41 is provided with a pinhole 43 through which the needle 16 passes vertically, the presser foot plate 41 is further provided with a plurality of partial portions 44 located at the front end of the pinhole 43 and a heating wire 45 inserted into the plurality of partial portions 44, a trimming groove 46 located at the front end of the pinhole 43 is formed between two adjacent partial portions 44, and a part of the heating wire 45 is exposed from the trimming groove 46 and located in front of the needle 16. When the sewing machine is used for sewing again, the sewing thread 17 is fixed on the surface of the sewing product by the machine needle 16, the sewing thread head 171 is still fixed in the first air suction channel 31, the sewing product moves forwards, so that the sewing thread head 171 is driven to move forwards in the needle hole 43, and the sewing thread head 171 is burnt and broken when being contacted with the heating wire 45 which is electrified and heated to about 200 ℃, so that the sewing thread head 171 is automatically trimmed, an operator is not required to manually trim the sewing thread head 171 on the surface of the sewing product after the sewing is finished, and the working efficiency is greatly improved.

Preferably, an insulating tube fixed in the thread separating part 44 is arranged between the heating wire 45 and the thread separating part 44 to isolate the heating wire 45 and the presser foot 4, so that the heating wire and the presser foot are not conducted, and the use safety of the sewing machine is ensured. The thread dividing part 44 is in a V shape, and the tip end of the thread dividing part 44 at the rear side faces the needle 16, so that when the sewing product drives the thread to move forward in the sewing process, the thread end 171 of the sewing thread is convenient to contact with the heating wire 45 exposed from the thread cutting groove 46, and the function of guiding is achieved.

Preferably, the connection structure of the heating wire 45 and the power line is as follows: as shown in fig. 10 and 12, mounting grooves are respectively formed on the outer surfaces of the two presser foot arms 42 of the presser foot 4, an insulating connecting block 47 is arranged in the mounting groove, a power line jack 471 which is through up and down is formed in the connecting block 47, the lower end of the power line is inserted into the power line jack 471 of the connecting block 47, the end of the heating wire 45 and the end of the power line are fixed and conducted by the screw 14, and the screw 14 simultaneously fixes the connecting block 47 on the presser foot arms 42.

Fig. 13 is a second embodiment of the presser foot assembly of the present application, which is different from the first embodiment in that: the presser foot base 3 has a different structure in which the first suction port 32 is formed. As shown in fig. 13 to 18, in the second embodiment, the lower end of the rear wall of the presser foot mounting portion 36 of the presser foot base 3 extends downward to the upper surface of the presser foot plate 41, and the first air suction opening 32 is directly opened on the rear wall of the presser foot mounting portion 36 and faces the needle 16.

As shown in fig. 19 to 21, the third embodiment of the presser foot assembly of the sewing machine differs from the first embodiment in that: the suction pipe 6 is connected with the presser foot 4 to form an integral component, the third suction channel 61 in the suction pipe 6 is directly connected with the first suction channel 31 in the presser foot seat 3, and the second suction channel 21 is not arranged in the presser foot rod 2.

The fourth embodiment of the presser foot assembly of the sewing machine has the following differences from the first embodiment: the first air suction channel 31 and the first air suction opening 32 are arranged on the presser foot 4, the air suction pipe 6 is connected with the presser foot 4 to form an integral component, the third air suction channel 61 in the air suction pipe 6 is directly connected with the first air suction channel 31 in the presser foot 4, and the second air suction channel 21 is not arranged in the presser foot rod 2. Specifically, as shown in fig. 22 and 23, the presser foot assembly of the sewing machine includes a presser bar 2 capable of moving up and down, a presser foot 4 installed at the lower end of the presser bar 2, a first air suction channel 31 and a first air suction port 32 located at the end of the first air suction channel 31 and facing the sewing machine needle 16 are opened in the presser foot 4, a thread clamping sheet 5 located in the first air suction channel 31 and capable of rotating up and down is hinged in the presser foot 4, and a thread clamping part 33 located in the first air suction channel 31 is further provided on the presser foot 4; when the presser foot 4 is lifted, the presser bar 2 moves up, the thread clamping piece 5 turns downwards, and the head of the sewing thread penetrating the sewing machine needle 16 is sucked into the first air suction channel 31 at the first air suction opening 32; when the presser foot 4 is lowered, the presser bar 2 moves down, the thread tension sheet 5 turns upward, and the sewing thread end is held between the thread tension sheet 5 and the thread tension part 33.

The presser bar 2 and the presser foot 4 are connected to each other through a presser foot base 3, the presser foot base 3 includes a presser bar mounting portion 35 connected to the lower end of the presser bar 2 and two presser foot mounting arms 37 provided on both left and right sides of the lower end of the presser bar mounting portion 35, the presser foot 4 includes a presser foot plate 41 and a presser foot base connecting portion 48 projecting upward, the presser foot base connecting portion 48 is located between the two presser foot mounting arms 37, and the first air suction passage 31 and the first air suction port 32 are both provided on the presser foot base connecting portion 48 of the presser foot 4.

The external air draft equipment can be in a normally open state in the sewing process, and the external air draft equipment can automatically work when the presser foot 4 is lifted up through an electric control module of the sewing machine; the heating wire 45 is electrified to generate heat for 2-5 seconds when the presser foot 4 is lifted under the control of the electric control module of the sewing machine. The working principle of the presser foot assembly of the sewing machine designed by the invention is as follows (the embodiment I of the presser foot assembly is used for explanation):

in the first and second sewing processes

The presser foot 4 is always in a laid-down state, as shown in fig. 4, the second air suction opening 22 and the third air suction opening 71 are blocked by the blocking part 23 on the presser foot rod 2, and the two are not communicated; there is no suction force at the first suction passage 31 and the first suction port 32. The striker 8 is in the initial state: the first return spring 11 is in a free state, a space L is formed between the upper end of the striker 8 and the stopper 9, and the lower end of the striker 8 is not in contact with the thread clamping piece 5. The rear end of the wire clamping piece 5 is in contact with the magnet 13, and the wire clamping piece 5 blocks the first air suction opening 32.

Second, when sewing is finished

Cutting off the sewing thread 17; the presser foot 4 is lifted, as shown in fig. 3 or fig. 13, the lower end of the striker 8 contacts with the upper end face of the thread clamping piece 5, the rear end of the thread clamping piece 5 is rotated downward, and the first air suction opening 32 is opened; meanwhile, the second air suction opening 22 and the third air suction opening 71 are aligned and communicated, and the sewing thread end 171 penetrating through the needle 16 is sucked into the first air suction channel 31 from the first air suction opening 32 under the action of the external air suction device.

Third, when sewing again

When the presser foot 4 is put down, as shown in fig. 4, the second air suction opening 22 and the third air suction opening 71 are blocked by the blocking part 23 on the presser bar 2, and no suction force exists at the first air suction channel 31 and the first air suction opening 32; meanwhile, under the action of the first return spring 11, the striker 8 is reset and separated from the thread clamping piece 5, the thread clamping piece 5 is released, the rear end of the thread clamping piece 5 is turned upwards under the action of the second return spring 12 and the magnet 13 to block the first air suction opening 32, and the sewing thread end 171 is fixedly clamped between the thread clamping piece 5 and the thread clamping part 33 of the presser foot seat 3.

The sewing machine is started for sewing, the sewing thread is fixed on a sewing product, meanwhile, an electric control module of the sewing machine controls the heating wire 45 to be electrified and generate heat, the sewing product drives the sewing thread to move forwards, the sewing thread is burnt and broken after being contacted with the heating wire 45, the burnt and broken sewing thread head is still fixedly clamped between the thread clamping piece 5 and the thread clamping part 33 of the presser foot seat 3, and the burnt and broken sewing thread head is drawn away after the presser foot 4 is lifted after the sewing is finished.

In conclusion, the invention has the following beneficial effects: when sewing the sewing product, the stitch is smooth and not disordered, the phenomenon of poor threading is avoided, and the sewing thread end can be automatically cut off, so that an operator does not need to manually trim the sewing thread end left on the surface of the sewing product after sewing is finished, and the sewing efficiency is greatly improved while the quality of the sewing product is improved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. The utility model provides a presser foot subassembly of sewing machine, includes presser foot (4) that has presser foot board (41), set up pinhole (43) that hold quick-witted needle (16) and pass from top to bottom on presser foot board (41), its characterized in that: the thread clamping device is characterized by further comprising a presser foot seat (3) and a thread clamping piece (5) hinged to the presser foot seat (3), wherein the presser foot (4) is installed at the lower end of the presser foot seat (3), a first air suction channel (31), a first air suction opening (32) located at the end of the first air suction channel (31) and facing the needle (16), and a thread clamping part (33) located in the first air suction channel (31) are arranged in the presser foot seat (3), and the thread clamping piece (5) is located in the first air suction channel (31) and can rotate up and down; the pressing foot plate (41) is also internally provided with a trimming groove (46) which is positioned at the front end of the needle hole (43) and communicated with the needle hole (43), a heating wire (45) penetrates through the pressing foot plate (41), and part of the heating wire (45) is exposed out of the trimming groove (46) and positioned in front of the needle (16); when the presser foot (4) is lifted, the thread clamping sheet (5) is turned downwards, and a sewing thread end (171) penetrating through the needle (16) is sucked into the first air suction channel (31) at the first air suction opening (32); when the presser foot (4) is put down, the thread clamping sheet (5) turns upwards, and the sewing thread head (171) is clamped between the thread clamping sheet (5) and the thread clamping part (33) in the presser foot component of the sewing machine; when sewing, the sewing thread (17) is fixed on the sewing product, and the sewing product drives the sewing thread (17) to move forwards so that the sewing thread (17) is contacted with the heating wire (45).

2. The sewing machine presser foot assembly of claim 1, wherein: the pressing foot plate (41) is provided with a plurality of line dividing parts (44) positioned at the front end of the needle hole (43), the line shearing groove (46) is formed between every two adjacent line dividing parts (44), and the heating wire (45) penetrates through the line dividing parts (44).

3. The sewing machine presser foot assembly of claim 2, wherein: an insulating tube fixed in the wire dividing part (44) is arranged between the wire dividing part (44) and the heating wire (45), and the insulating tube is used for isolating the heating wire (45) from the presser foot (4).

4. The sewing machine presser foot assembly of claim 2, wherein: the parting part (44) is V-shaped, and the tip end at the rear side of the parting part (44) faces the needle (16).

5. The sewing machine presser foot assembly of claim 1, wherein: the presser foot (4) further comprises two presser foot arms (42) arranged on the upper end face of the presser foot plate (41), a connecting block (47) is fixed on the outer surface of each presser foot arm (42), a power line jack (471) is formed in each connecting block (47), and the two ends of the heating wire (45) and the end of the power line are both arranged in the power line jacks (471) and are fixed and conducted through fasteners.

6. The sewing machine presser foot assembly of claim 1, wherein: also comprises an air suction pipe (6) and a presser foot rod sleeve (7) which are fixed in the sewing machine shell (1), and a presser foot rod (2) which can be vertically moved and is arranged in the presser foot rod sleeve (7) in a penetrating way, the pressure foot seat (3) is arranged at the lower end of the pressure foot rod (2), a second air suction channel (21) communicated with the first air suction channel (31) is arranged in the pressure foot rod (2), a second air suction opening (22) communicated with the second air suction channel (21) is arranged on the outer wall of the pressure foot rod (2), the pressure foot rod (2) is also provided with a blocking part (23) above the second air suction opening (22), a third air suction channel (61) is arranged in the air suction pipe (6), and the air suction pipe (6) is connected with an external air suction device, a third air suction opening (71) communicated with the third air suction channel (61) is formed in the outer wall of the pressure foot rod sleeve (7); when the presser bar (2) moves upwards, the second air suction opening (22) is communicated with the third air suction opening (71); when the presser bar (2) moves downwards, the second air suction opening (22) and the third air suction opening (71) are blocked by the blocking part (23).

7. The sewing machine presser foot assembly of claim 1, wherein: the sewing machine is characterized by further comprising a presser foot rod sleeve (7) fixed in the sewing machine shell (1), a presser foot rod (2) capable of penetrating through the presser foot rod sleeve (7) in a vertically movable mode, a striker (8) capable of moving vertically, a stop block (9) fixed at the lower end of the presser foot rod sleeve (7) and a bushing (10) fixed on the presser foot rod (2), wherein the presser foot seat (3) is installed at the lower end of the presser foot rod (2), a first through hole (101) extending vertically is formed in the bushing (10), a second through hole (34) extending vertically and communicated with the first air suction channel (31) is formed in the presser foot seat (3), the striker (8) penetrates through the first through hole (101) and the second through hole (34) in sequence, and the upper end of the striker (8) is arranged above the bushing (10); when the presser foot (4) is put down, the distance between the upper end of the firing pin (8) and the lower end of the stop block (9) is smaller than the stroke of the presser foot rod (2) moving upwards when the presser foot (4) is lifted.

8. The utility model provides a presser foot subassembly of sewing machine, includes presser foot (4) that has presser foot board (41), set up pinhole (43) that hold quick-witted needle (16) and pass from top to bottom on presser foot board (41), its characterized in that: the novel sewing machine is characterized by further comprising a presser foot seat (3) and a thread clamping piece (5) hinged to the presser foot (4), wherein the presser foot (4) is installed at the lower end of the presser foot seat (3), a first air suction channel (31), a first air suction opening (32) located at the end of the first air suction channel (31) and facing the sewing needle (16), and a thread clamping part (33) located in the first air suction channel (31) are arranged in the presser foot (4), and the thread clamping piece (5) is located in the first air suction channel (31) and can rotate up and down; the pressing foot plate (41) is also internally provided with a trimming groove (46) which is positioned at the front end of the needle hole (43) and communicated with the needle hole (43), a heating wire (45) penetrates through the pressing foot plate (41), and part of the heating wire (45) is exposed out of the trimming groove (46) and positioned in front of the needle (16); when the presser foot (4) is lifted, the thread clamping sheet (5) is turned downwards, and a sewing thread end (171) penetrating through the needle (16) is sucked into the first air suction channel (31) at the first air suction opening (32); when the presser foot (4) is put down, the thread clamping sheet (5) turns upwards, and the sewing thread head (171) is clamped between the thread clamping sheet (5) and the thread clamping part (33) in the presser foot assembly of the sewing machine; when sewing, the sewing thread (17) is fixed on the sewing product, and the sewing product drives the sewing thread (17) to move forwards so that the sewing thread (17) is contacted with the heating wire (45).

9. The sewing machine presser foot assembly of claim 8, wherein: the novel sewing machine is characterized by further comprising a presser foot rod sleeve (7) fixed in the sewing machine shell (1), a presser foot rod (2) capable of penetrating through the presser foot rod sleeve (7) in a vertically moving mode and an air suction pipe (6) provided with a third air suction channel (61), wherein the lower end of the presser foot rod (2) is installed on the presser foot seat (3), the air suction pipe (6) is connected with the presser foot (4) to form an integral component, the air suction pipe (6) is connected with external air suction equipment, and the third air suction channel (61) is connected with the first air suction channel (31).

10. The sewing machine presser foot assembly of claim 8, wherein: the sewing machine is characterized by further comprising a presser foot rod sleeve (7) fixed in the sewing machine shell (1), a presser foot rod (2) capable of penetrating through the presser foot rod sleeve (7) in a vertically movable mode, a striker (8) capable of moving vertically, a stop block (9) fixed at the lower end of the presser foot rod sleeve (7) and a bushing (10) fixed on the presser foot rod (2), wherein the presser foot seat (3) is installed at the lower end of the presser foot rod (2), a first through hole (101) extending vertically is formed in the bushing (10), a second through hole (34) extending vertically and communicated with the first air suction channel (31) is formed in the presser foot seat (3), the striker (8) penetrates through the first through hole (101) and the second through hole (34) in sequence, and the upper end of the striker (8) is arranged above the bushing (10); when the presser foot (4) is put down, the distance between the upper end of the firing pin (8) and the lower end of the stop block (9) is smaller than the stroke of the presser foot rod (2) moving upwards when the presser foot (4) is lifted.