CN112626734B

CN112626734B - Sewing machine

Info

Publication number: CN112626734B
Application number: CN201910906980.4A
Authority: CN
Inventors: 柯祥林; 祝书伟; 郑吉�; 何明金
Original assignee: Jack Sewing Machine Co Ltd
Current assignee: Jack Technology Co Ltd
Priority date: 2019-09-24
Filing date: 2019-09-24
Publication date: 2021-12-28
Anticipated expiration: 2039-09-24
Also published as: CN112626734A

Abstract

The invention provides a sewing machine, which comprises a main shaft, a tooth frame, a feeding tooth, a tooth lifting mechanism connected between the main shaft and the tooth frame, a presser foot lifting driving source, a presser foot lifting transmission component connected between the presser foot lifting driving source and the presser foot, and a lower supply transmission component, wherein a presser foot lifting transmission component in the presser foot lifting transmission component is connected with a tooth lifting transmission component in the tooth lifting mechanism through the lower supply transmission component; when the sewing machine stops and takes and places the sewing materials, a machine needle in the sewing machine is positioned above the needle plate, the presser foot lifting driving source acts, the presser foot is driven to lift upwards through the presser foot lifting transmission assembly, the presser foot is enabled to be positioned above the needle plate, meanwhile, the presser foot lifting transmission component drives the tooth lifting transmission component to act through the lower power supply transmission assembly, the tooth rack and the feeding teeth are driven to move, the feeding teeth are enabled to descend below the upper surface of the needle plate, the feeding teeth can automatically descend below the needle plate when the presser foot is lifted, the feeding teeth cannot influence the placement of the sewing materials on the needle plate, and the sewing materials are convenient to take and place.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine.

Background

The existing sewing machine (such as a flat sewing machine) generally comprises a main shaft driven and rotated by the main shaft, a feed lifting tooth shaft and a feed feeding shaft which are parallel to the main shaft, a needle rod extending up and down, a machine needle arranged at the lower end of the needle rod, a tooth frame and feed feeding teeth fixed on the tooth frame, wherein the main shaft is connected with the feed lifting tooth shaft through a first feed lifting tooth transmission component, the feed lifting tooth shaft is connected with one end of the tooth frame through a second feed lifting tooth transmission component, the main shaft is connected with the feed feeding shaft through the first feed feeding transmission component, the feed feeding shaft is connected with the other end of the tooth frame through the second feed feeding transmission component, and the main shaft is further connected with the needle rod through the needle rod transmission component. The structure of each transmission assembly can refer to a sewing machine disclosed in the Chinese patent with the application number of 201310198530.7. Therefore, in the existing sewing machine, the movement of the needle and the feeding tooth are driven by the main shaft, so that the needle and the feeding tooth are in synchronous linkage.

Further, when the sewing machine is stopped, as shown in fig. 1, in order to ensure that the sewing material 500 is normally put under the presser foot 200 and on the needle plate 400, the needle 100 and the presser foot 200 in the sewing machine must be positioned above the needle plate 400, the presser foot 200 is driven to be lifted by the presser foot lifting mechanism in the sewing machine, and the needle 100 is driven to move to the highest point by the operator by rotating the hand wheel fixed at the end of the main shaft. However, due to the synchronous linkage relationship between the needle 100 and the feeding teeth 300, when the needle 100 is located above the needle plate 400, the feeding teeth 300 also protrude upwards from the tooth grooves of the needle plate 400, that is, a part of the feeding teeth 300 is exposed upwards from the needle plate 400, at this time, the sewing material 500 cannot be flatly placed on the needle plate 400, and particularly for elastic thin materials, the elastic thin materials are easily hung by the feeding teeth 300 to cause uneven placement; meanwhile, the feeding tooth 300 also protrudes upwards from the needle plate 400, so that the feeding tooth 300 can drive the sewing material 500 forward for a certain distance when the sewing machine starts sewing, the needle falling point of the needle 100 is affected, the sewing quality is affected, and the sewing experience is greatly 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 sewing machine capable of driving feed dogs to descend below a needle plate during a presser foot lifting process, so as to facilitate taking and placing of a sewing material.

In order to achieve the purpose, the invention provides a sewing machine, which comprises a main shaft, a tooth rack, a feeding tooth arranged on the tooth rack, a tooth lifting mechanism connected between the main shaft and the tooth rack, a presser foot lifting driving source, a presser foot lifting transmission assembly connected between the presser foot lifting driving source and the presser foot, and a lower supply transmission assembly, wherein a presser foot lifting transmission part in the presser foot lifting transmission assembly is connected with a tooth lifting transmission part in the tooth lifting mechanism through the lower supply transmission assembly; when the presser foot lifting driving source acts, the presser foot is driven to lift upwards through the presser foot lifting transmission assembly, meanwhile, the presser foot lifting transmission component drives the tooth lifting transmission component to act through the lower supply transmission assembly, and the tooth frame and the feeding teeth are driven to move, so that the feeding teeth fall below the upper surface of the needle plate.

Further, the tooth lifting mechanism comprises a tooth lifting shaft parallel to the main shaft, a first tooth lifting transmission component connected between the main shaft and the tooth lifting shaft, and a second tooth lifting transmission component connected between the tooth lifting shaft and the tooth frame, wherein the tooth lifting transmission component is one transmission component in the first tooth lifting transmission component.

Furthermore, the first lifting tooth transmission component comprises a lifting tooth eccentric wheel fixed on the main shaft, a lifting tooth connecting rod, a lifting tooth swinging seat with a first fixed swinging fulcrum O1, a first swinging plate, a second swinging plate and a lifting tooth crank fixed on the lifting tooth shaft, one end of the lifting tooth connecting rod is rotatably sleeved on the periphery of the lifting tooth eccentric wheel, the other end of the lifting tooth connecting rod, one end of the first swinging plate and one end of the second swinging plate are coaxially hinged, the other end of the first swinging plate is hinged with the lifting tooth swinging seat, the other end of the second swinging plate is hinged with the lifting tooth crank, and the lifting and pressing foot transmission component is connected with the lifting tooth swinging seat through a lower supply transmission component; when the presser foot lifting driving source drives the presser foot to be lifted upwards through the presser foot lifting transmission component, the presser foot lifting transmission component drives the tooth lifting swing seat to rotate around the first fixed swing fulcrum O1 through the lower supply transmission component.

Further, the lower supply transmission assembly comprises a lower supply pull rod, an adjusting crank with a second fixed swing fulcrum O2 and an adjusting connecting rod, one end of the lower supply pull rod is hinged with the pressure lifting and pressing foot transmission component, the other end of the lower supply pull rod is hinged with the adjusting connecting rod, and the adjusting connecting rod is respectively hinged with the adjusting crank and the tooth lifting swing seat.

Further, the sewing machine further comprises an adjusting knob and an adjusting stud in the sewing machine shell in a threaded connection mode, the adjusting knob is fixed to one end of the adjusting stud, and the other end of the adjusting stud is abutted to the adjusting crank and can drive the adjusting crank to rotate around a second fixed swing fulcrum O2.

Furthermore, a section of idle stroke section is arranged in the lower pull supply rod, the lower pull supply rod is hinged with the adjusting connecting rod through a shaft position screw fixed on the adjusting connecting rod, and the shaft position screw penetrates through the idle stroke section of the lower pull supply rod; when the adjusting knob drives the adjusting stud to move, the shaft position screw moves in the idle stroke section of the lower supply pull rod.

Furthermore, the sewing machine further comprises a swinging seat return spring, and two ends of the swinging seat return spring are respectively connected with the adjusting connecting rod and the sewing machine shell.

Furthermore, the second tooth lifting transmission assembly comprises a sliding block and a tooth lifting swing fork fixed on the tooth lifting shaft, the sliding block is hinged with the tooth frame, a sliding groove is formed in the tooth lifting swing fork, and the sliding block is located in the sliding groove and in sliding fit with the sliding groove.

Further, the presser foot lifting transmission assembly comprises a right lever with a third fixed swing fulcrum O3, a presser foot lifting pull rod, a left lever with a fourth fixed swing fulcrum O4, a presser foot lifting plate, a pressure lever guide frame and a pressure lever extending up and down, wherein the presser foot lifting driving source is hinged to one end of the right lever and drives the right lever to rotate around the third fixed swing fulcrum O3, the other end of the right lever is hinged to one end of the presser foot lifting pull rod, the other end of the presser foot lifting pull rod is hinged to one end of the left lever, the other end of the left lever is hinged to the upper end of the presser foot lifting plate, a lifting hook part is arranged on the presser foot lifting plate, a connecting projection part clamped with the lifting hook part is arranged on the pressure lever guide frame, the pressure lever guide frame is fixed to the upper end of the pressure lever, and the presser foot is mounted at the lower end of the pressure lever; the right lever is connected with the tooth lifting transmission part through a lower transmission supply assembly.

As described above, the sewing machine according to the present invention has the following advantageous effects:

this application can also make the pay-off tooth automatic drop to below the faller when realizing lifting the presser foot, realize also that eedle and presser foot all are in the top of faller, nevertheless pay-off tooth is below the upper surface of faller, so pay-off tooth can not place the production influence on the faller to the sewing material, is convenient for get and puts the sewing material, and pay-off tooth also can not drive one section distance earlier with the sewing material when starting up the seam next time to guarantee the accuracy of needle point, guarantee the sewing quality.

Drawings

FIG. 1 is a view showing a state in which a sewing material is put in a conventional sewing machine.

Fig. 2 and 3 are schematic views of the sewing machine of the present application at different viewing angles.

Fig. 4 is an enlarged view of circle a of fig. 2.

Fig. 5 is an enlarged view of circle B of fig. 2.

Fig. 6 is a schematic structural diagram of a lower power supply transmission assembly in the present application.

Fig. 7 is a schematic structural view of a presser foot lifting transmission assembly in the present application.

Description of the element reference numerals

10 spindle

20 dental articulator

30 feeding tooth

40 lifting tooth mechanism

41 lifting tooth shaft

42 eccentric cam of lifting tooth

43 lifting tooth connecting rod

44 lifting tooth swing seat

441 seat arm part

45 first swinging plate

46 second swinging plate

47 lifting rock shaft crank

48 slide block

49 lifting tooth swing fork

491 chute

410 support pin

50 swing seat return spring

60 presser foot

70 lift presser foot driving source

71 iron core joint

80 lower supply transmission assembly

81 lower supply pull rod

811 idle stroke section

82 adjusting crank

83 adjusting connecting rod

831 link body part

832 connecting rod arm

84 adjusting knob

85 adjusting stud

86 adjusting pin

87 spring pin

90 lift presser foot drive assembly

91 right lever

92 lifting presser foot pull rod

93 left lever

94 lifting pressure foot lifting plate

941 lifting hook

95 compression bar guide frame

951 connecting protrusion

96 pressure lever

97 presser foot reset spring

110 machine needle

120 needle board

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.

The present application provides a sewing machine, such as a flat bed sewing machine. For convenience of description, the following embodiments define the directions as follows: as shown in fig. 2, the axial direction of the main shaft 10 in the sewing machine is defined as a left-right direction, the direction of the main shaft 10 towards the head of the sewing machine is a left direction (i.e. the left side of the paper surface in the view of fig. 2), and the direction of the main shaft 10 towards the tail of the sewing machine is a right direction (i.e. the right side of the paper surface in the view of fig. 2); the moving direction of the sewing material when the sewing machine is used for sewing is defined as a front direction.

As shown in fig. 2 and 3, the sewing machine according to the present invention includes a main shaft 10 extending left and right, a thread frame 20, a feed dog 30 mounted on the thread frame 20, a feed mechanism connected between the main shaft 10 and the front end of the thread frame 20, a feed dog mechanism 40 connected between the main shaft 10 and the rear end of the thread frame 20, a presser foot 60, a presser foot lifting drive source 70, a presser foot lifting drive assembly 90 connected between the presser foot lifting drive source 70 and the presser foot 60, a needle plate 120, a needle bar extending up and down, a machine needle 110 mounted at the lower end of the needle bar, a needle bar drive assembly connected between the main shaft 10 and the needle bar, and a lower supply drive assembly 80; the feeding mechanism and the needle bar transmission assembly in the sewing machine are the prior art, and the feeding mechanism and the needle bar transmission assembly are not described in an expanded mode. In particular, the present application relates to a sewing machine wherein a presser foot drive member of the presser foot drive assembly 90 is connected to a feed dog drive member of the feed dog mechanism 40 via the lower feed drive assembly 80.

When the sewing machine is used for normal sewing, the presser foot lifting drive source 70 does not act, the presser foot 60 is in a laid-down state, sewn sewing materials are pressed on the needle plate 120, the main shaft 10 is driven by the main motor to rotate, the main shaft 10 drives the tooth frame 20 and the feeding teeth 30 to reciprocate back and forth through the feeding mechanism, the main shaft 10 drives the tooth frame 20 and the feeding teeth 30 to reciprocate up and down through the tooth lifting mechanism 40, therefore, the feeding teeth 30 do periodic compound motion of back and forth reciprocating motion and up and down reciprocating motion, and the motion trail of the feeding teeth 30 is elliptical. Meanwhile, the main shaft 10 drives the needle rod and the needle 110 to reciprocate up and down through the needle rod transmission assembly, and the needle 110 and the feeding tooth 30 move in a matched mode to realize sewing of sewing materials. Specifically, when the sewing machine stops operating to take the sewn sewing material from the needle plate 120 or put the sewing material to be sewn on the needle plate 120, a hand wheel fixed at the right end of the main shaft 10 is rotated (the hand wheel is not shown in fig. 2 and 3) to position the needle 110 above the needle plate 120, and the presser foot lifting drive source 70 operates, the presser foot lifting drive source 70 drives the presser foot 60 to lift upwards through the presser foot lifting drive assembly 90, so that the presser foot 60 is positioned above the needle plate 120, the presser foot lifting drive component in the presser foot lifting drive assembly 90 drives the tooth lifting drive component in the tooth lifting mechanism 40 to operate through the lower supply drive assembly 80, so as to drive the tooth frame 20 and the feed tooth 30 to move, so that the feed tooth 30 moves downwards below the upper surface of the needle plate 120, and at this time, the upper surface of the feed tooth 30 is flush with the upper surface of the needle plate 120 or the upper surface of the feed tooth 30 is positioned below the upper surface of the needle plate 120. Therefore, this application can the simultaneous control pay-off tooth 30 descend when lifting presser foot 60 and getting and put the seam material, in the lump with pay-off tooth 30 automatic fall to below the upper surface of faller 120, can realize that eedle 110 and presser foot 60 are all in the top of faller 120 when getting and put the seam material, nevertheless pay-off tooth 30 does not upwards emerge from faller 120, so pay-off tooth 30 can not place the seam material and produce the influence on faller 120, be convenient for get and put the seam material, will stitch the material earlier forward one section distance when can not starting to sew up again yet, guarantee the accuracy of needle point, thereby guarantee the sewing quality, promote user experience greatly, improve sewing machine's product competitiveness.

Further, the presser foot lifting drive source 70 may be an electromagnet, an air cylinder, a linear motor, or the like, or the presser foot lifting drive source 70 may be a knee presser foot lifting wrench. In the following embodiment, the presser foot lifting drive source 70 is an electromagnet having an iron core that can be extended and retracted up and down, and an iron core joint 71 is fixedly connected to the upper end of the iron core. As shown in fig. 2 and 3, and fig. 7, the lift and press foot transmission assembly 90 includes a right lever 91 having a third fixed swing fulcrum O3, a lift and press foot pull lever 92, a left lever 93 having a fourth fixed swing fulcrum O4, a lift and press foot lifting plate 94, a press rod guide 95, and a press rod 96 extending up and down; the right lever 91 and the left lever 93 are hinged to a housing of the sewing machine by a shaft position screw extending back and forth; the right lever 91 comprises a right section rod part positioned on the right side of the third fixed swing fulcrum O3 and a left section rod part positioned on the left side of the third fixed swing fulcrum O3, the iron core joint 71 of the electromagnet is hinged with the right section rod part of the right lever 91, and the hinged point of the iron core joint and the right section rod part is positioned on the right side of the middle of the right section rod part, so that the pressure foot lifting and driving source 70 can drive the right lever 91 to rotate around the third fixed swing fulcrum O3; the end part of the left section rod part of the right lever 91 is hinged with the right end of the presser foot lifting pull rod 92; the left end of the presser foot lifting pull rod 92 is hinged with the upper right end of a left lever 93; the left lower end of the left lever 93 is hinged with the upper end of a pressure foot lifting plate 94; a lifting hook portion 941 is arranged on the pressure foot lifting plate 94, and a connecting protrusion portion 951 which is clamped with the lifting hook portion 941 is arranged on the pressure lever guide frame 95; a press rod guide 95 is fixed at the upper end of the press rod 96; the presser foot 60 is mounted to the lower end of the presser bar 96. Specifically, in the above-mentioned presser foot lifting transmission assembly 90, the end of the right-section rod portion of the right lever 91 is connected to the tooth lifting transmission member through the lower supply transmission assembly 80. Therefore, the right lever 91 of the presser foot lifting transmission assembly 90 constitutes a presser foot lifting transmission member connected to the lower supply transmission assembly 80. As shown in fig. 2, a presser foot return spring 97 is fitted over the presser bar 96.

As shown in fig. 2 and 3, the tooth lifting mechanism 40 includes a tooth lifting shaft 41 parallel to the main shaft 10, a first tooth lifting transmission component connected between the main shaft 10 and the tooth lifting shaft 41, and a second tooth lifting transmission component connected between the tooth lifting shaft 41 and the tooth frame 20, and the tooth lifting transmission component is one of the first tooth lifting transmission components.

As shown in fig. 2, 3 and 5, the first lifting tooth transmission assembly includes a lifting tooth eccentric wheel 42 fixed on the main shaft 10 by a screw, a lifting tooth connecting rod 43, a lifting tooth swinging seat 44 having a first fixed swinging fulcrum, a first swinging plate 45, a second swinging plate 46, and a lifting tooth crank 47 fixed on the lifting tooth shaft 41 by a screw, wherein the upper end of the lifting tooth connecting rod 43 is rotatably sleeved on the periphery of the lifting tooth eccentric wheel 42, the lower end of the lifting tooth connecting rod 43, the front end of the first swinging plate 45 and the front end of the second swinging plate 46 are coaxially hinged by a pin extending left and right, the rear end of the first swinging plate 45 is hinged with the lifting tooth swinging seat 44 by a pin extending left and right, and the rear end of the second swinging plate 46 is hinged with the lifting tooth crank 47 by a pin extending left and right. The right lever 91 in the lifting and pressing foot transmission assembly 90 is connected with the lifting tooth swinging seat 44 in the first lifting tooth transmission assembly through the lower supply transmission assembly 80, and the lifting tooth swinging seat 44 forms a lifting tooth transmission component. When the presser foot lifting driving source 70 drives the presser foot 60 to lift upwards through the presser foot lifting transmission assembly 90, the right lever 91 rotates around the third fixed swing fulcrum O3, so that the right lever 91 drives the tooth lifting swing seat 44 to rotate around the first fixed swing fulcrum O1 through the lower supply transmission assembly 80, the position angle of the tooth lifting swing seat 44 is changed, the tooth lifting shaft 41 rotates through an angle, the tooth lifting shaft 41 drives the tooth frame 20 and the feeding tooth 30 to move through the second tooth lifting transmission assembly, and the feeding tooth 30 moves downwards to be below the upper surface of the needle plate 120, so that the sewing material is convenient to take and place.

Preferably, as shown in fig. 5, the lift tooth swing seat 44 has two seat arm portions 441 arranged bilaterally symmetrically, two first swing plates 45 and two second swing plates 46 are disposed between the two seat arm portions 441, the two second swing plates 46 are disposed on the left and right sides of the lower end of the lift tooth link 43, and one first swing plate 45 is disposed between the first swing plate 45 and the seat arm portion 441. Each of the seat arm portions 441 is rotatably mounted to a support pin 410 extending leftward and rightward, and the support pin 410 is fixed to the sewing machine housing and constitutes a first fixed swing fulcrum O1 of the lift tooth swing seat 44.

As shown in fig. 2 and 4, the second tooth lifting transmission assembly includes a sliding block 48 and a tooth lifting swing fork 49 fixed on the tooth lifting shaft 41 by screws, the sliding block 48 is hinged with the tooth frame 20 by a pin extending left and right, a sliding groove 491 is formed in the tooth lifting swing fork 49, the sliding block 48 is located in the sliding groove 491, and the two are in sliding fit. Preferably, the slider 48 is in surface contact with the groove wall of the chute 491.

As shown in fig. 2 and 3, and fig. 6, the lower supply transmission assembly 80 includes a lower supply link 81, an adjustment crank 82 having a second fixed swing fulcrum O2, and an adjustment link 83, the adjustment link 83 is substantially T-shaped, and has a link body 831 and a link arm 832 extending forward from a front side of the link body 831, an upper end of the lower supply link 81 is hinged to a right end of the right lever 91 by a forward-rearward extending axial screw, a lower end of the lower supply link 81 is hinged to a front end of the link arm 832 of the adjustment link 83 by a forward-rearward extending axial screw, a shaft screw for hinging the lower supply link 81 and the adjusting link 83 is fixed in the link arm 832 of the adjusting link 83, the upper end of the connecting rod body 831 of the adjusting connecting rod 83 is hinged to the front end of the adjusting crank 82 through a pin extending left and right, and the lower end of the connecting rod body 831 of the adjusting connecting rod 83 is hinged to the seat arm 441 of the lifting tooth swing seat 44 through a pin extending left and right. Preferably, the lower feeding transmission assembly 80 further includes an adjustment pin 86 fixed to the sewing machine frame, the adjustment pin 86 extending left and right, and the adjustment crank 82 rotatably mounted to the adjustment pin 86 such that the adjustment pin 86 constitutes a second fixed swing fulcrum O2 of the adjustment crank 82.

As shown in fig. 2 and 3, the sewing machine further includes an adjusting knob 84 and an adjusting stud 85 that is screwed into the sewing machine housing and extends forward and backward, the adjusting knob 84 is fixed to a rear end of the adjusting stud 85, a front end of the adjusting stud 85 abuts against a rear end surface of the adjusting crank 82, and the adjusting stud 85 is offset with respect to a second fixed swing fulcrum O2 of the adjusting crank 82. When the adjusting knob 84 is rotated, the adjusting knob 84 drives the adjusting stud 85 to rotate together, so that the adjusting stud 85 is driven to move in the front-rear direction, the adjusting crank 82 is driven to rotate around the second fixed swing fulcrum O2, when the adjusting crank 82 rotates, the adjusting connecting rod 83 drives the feed lifting teeth swinging seat 44 to rotate around the first fixed swing fulcrum O1, so that the position angle of the feed lifting teeth swinging seat 44 is changed, the transmission efficiency between the main shaft 10 and the feed lifting teeth shaft 41 is changed, and the feed lifting teeth 30 is adjusted in height. Preferably, the sewing machine further comprises a swing seat return spring 50, a spring pin 87 is fixed on the adjusting connecting rod 83, the upper end of the swing seat return spring 50 is connected with the spring pin 87, namely the upper end of the swing seat return spring 50 is connected with the adjusting connecting rod 83 through the spring pin 87, and the lower end of the swing seat return spring 50 is connected with the sewing machine shell. The swing seat return spring 50 applies acting force to the adjusting connecting rod 83 and indirectly applies acting force to the adjusting crank 82, so that the adjusting crank 82 and the adjusting stud 85 are always tightly attached, and the reliability of the lifting tooth height adjustment is improved; in addition, in the process of lifting the presser foot, the right lever 91 drives the swing seat 44 of the lifting tooth to rotate for an angle through the lower supply pull rod 81, the adjusting crank 82 and the adjusting connecting rod 83, so that the feeding tooth 30 descends, and the return spring 50 of the swing seat is in an energy storage state in the process; after the presser foot 60 is lowered after the presser foot is lifted, the right lever 91 is reset, and the adjusting connecting rod 83 is reset under the action of the swing seat reset spring 50, so that the adjusting crank 82 and the feed lifting tooth swing seat 44 are also reset, namely the matching relation between the feed feeding tooth 30 and the needle 110 is restored.

Further, in the process of adjusting the height of the feed dog 30, the adjusting link 83 moves, and in order to prevent the adjusting link 83 from driving the right lever 91 to rotate through the lower supply pull rod 81 in the process, as shown in fig. 6, the lower end of the lower supply pull rod 81 is provided with a section of idle stroke section 811, the idle stroke section 811 is an idle slot extending along the extending direction of the lower supply pull rod 81, so that the lower end of the lower supply pull rod 81 is of a slot-shaped structure and provides a section of idle stroke section 811, and a shaft position screw for hinging the lower supply pull rod 81 and the adjusting link 83 is arranged in the idle stroke section 811 of the lower supply pull rod 81 in a penetrating manner; when the adjusting knob 84 drives the adjusting stud 85 to move, although the adjusting crank 82 drives the adjusting connecting rod 83 to move, in the process, the axial screw moves in the idle stroke section 811 of the lower supply pull rod 81, so that the lower supply pull rod 81 does not act, the pressure raising and pressing foot transmission assembly 90 does not act, and therefore the adjustment of the tooth raising height does not affect the pressure raising and pressing foot transmission assembly 90. Preferably, the idle stroke 811 of the lower end of the lower feed link 81 should satisfy the following condition: can accommodate the distance of the up-and-down movement of the adjusting link 83 caused by the change of the position angle of the lifting tooth swinging seat 44 in the lifting tooth height adjusting process.

In summary, the sewing machine with the above structure works according to the following principle:

when the sewing machine sews normally, the electromagnet is in a power-off state, the swing seat return spring 50 enables the front end of the adjusting screw rod to be always abutted against the rear end face of the adjusting crank 82, the lifting tooth swing seat 44 is in a static state, and is kept in a fixed position angle and in a static state under the limit of the adjusting crank 82 and the adjusting connecting rod 83. The main shaft 10 drives the feed lifting tooth shaft 41 to do periodic reciprocating swing through the first transmission component, the feed lifting tooth shaft 41 drives the tooth frame 20 and the feed feeding tooth 30 to do periodic up-down reciprocating movement through the second transmission component, and the amplitude of the up-down reciprocating movement of the feed feeding tooth 30 is related to the swing amplitude of the feed lifting tooth shaft 41; the main shaft 10 drives the needle rod and the needle 110 to reciprocate up and down through the needle rod transmission component, and the needle 110 and the feeding tooth 30 move in a matching way to realize sewing of sewing materials. When the sewing machine sews normally, the needle 110 and the feed dog 30 are in linkage relation and are driven by the main shaft 10.

When the sewing machine stops and needs to take and put sewing materials, the needle 110 moves to the upper part of the needle plate 120, and due to the synchronous linkage relation of the needle 110 and the feeding teeth 30, when the electromagnet is not electrified, the feeding teeth 30 also move to the upper part of the needle plate 120. When the electromagnet is electrified, the iron core of the electromagnet moves upwards and extends out to drive the iron core joint 71 to move upwards together, the iron core joint 71 drives the right lever 91 to rotate around the third fixed swing fulcrum O3, the right lever 91 pulls the presser foot lifting pull rod 92 rightwards, the presser foot lifting plate 94 is driven to move upwards through the left lever 93, and the press rod guide frame 95, the press rod 96 and the presser foot 60 are driven to move upwards together to lift the presser foot; meanwhile, the right lever 91 pulls the lower feed pull rod 81 to move upwards, the lower feed pull rod 81 after consuming the empty stroke section 811 abuts against a shaft position screw fixed in the adjusting connecting rod 83, then along with the continuous upward movement of the lower feed pull rod 81, the lower feed pull rod 81 drives the tooth lifting swing seat 44 to rotate to a certain angle around the first fixed swing fulcrum O1 through the adjusting connecting rod 83, and the tooth lifting swing seat 44 directly controls the tooth lifting height of the feed tooth 30, so that the feed tooth 30 is enabled to descend below the upper surface of the needle plate 120, and the taking and discharging are facilitated. Then, when the sewing machine starts to sew, the electromagnet is powered off, the presser foot 60 descends to the needle plate 120 under the action of the presser foot return spring 97, each component in the presser foot lifting transmission assembly 90 also resets, the right lever 91 drives the lower pull rod 81 to reset, and the tooth lifting swing seat 44 resets under the action of the swing seat return spring 50. Therefore, the feeding teeth 30 are automatically descended below the upper surface of the needle plate 120 in the process of lifting the presser foot. In particular, the needle 110 does not move in the above process, and the synchronous linkage relationship between the needle 110 and the feeding tooth 30 in the normal sewing of the subsequent sewing machine is not changed.

When the height of the feed dog is required to be adjusted, the adjusting knob 84 is rotated to enable the adjusting stud 85 to move forwards or backwards, so that the adjusting crank 82 is enabled to swing, the position angle of the feed dog swinging seat 44 is changed through the adjusting connecting rod 83, the swinging amplitude of the main shaft 10 which drives the feed dog shaft 41 to swing through the first feed dog transmission assembly during subsequent sewing is changed, the transmission efficiency between the main shaft 10 and the feed dog shaft 41 is changed, the height of the feed dog 30 is adjusted, and the feed dog is suitable for sewing of sewing materials with different thicknesses. Meanwhile, the axis position screw for hinging the lower supply pull rod 81 and the adjusting connecting rod 83 moves in the idle stroke section 811 of the lower supply pull rod 81, so that the pressure foot lifting transmission assembly 90 does not act when the tooth lifting height of the feeding tooth 30 is adjusted, and the height state of the pressure foot 60 is not changed. In particular, the sewing machine according to the present application adjusts the feed dog height of the feed dog 30 by changing the swing of the feed dog shaft 41, and can cause the movement locus of the feed dog 30 to change in an equal ratio only in the vertical direction relative to the upper surface of the needle plate 120 without causing the movement locus of the feed dog 30 to move up or down as a whole, so that the needle pitch of the sewing machine is kept unchanged during the adjustment of the feed dog height, and the sewing quality is not affected. Therefore, the height of the feed dog 30 can be adjusted within a certain range, stepless adjustment is achieved, the needle pitch cannot be changed while the height of the feed dog is adjusted, the sewing machine can have different heights of the feed dog according to sewing materials of different specifications, the sewing quality can be effectively guaranteed, the adaptability of the thick and thin sewing materials of the sewing machine is improved, the universality of the sewing machine is greatly improved, and the competitiveness of products is improved.

In conclusion, the present invention effectively overcomes various disadvantages of 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 sewing machine, includes main shaft (10), dental articulator (20), installs pay-off tooth (30) on dental articulator (20), connects tooth raising mechanism (40), presser foot (60) between main shaft (10) and dental articulator (20), lifts presser foot driving source (70) and connects and lift presser foot drive assembly (90) between presser foot driving source (70) and presser foot (60), its characterized in that: the tooth lifting mechanism further comprises a lower supply transmission assembly (80), wherein a lifting and pressing foot transmission part in the lifting and pressing foot transmission assembly (90) is connected with a tooth lifting transmission part in the tooth lifting mechanism (40) through the lower supply transmission assembly (80); when the presser foot lifting driving source (70) acts, the presser foot (60) is driven to lift upwards through the presser foot lifting transmission assembly (90), meanwhile, the presser foot lifting transmission component drives the tooth lifting transmission component to act through the lower supply transmission assembly (80), the tooth frame (20) and the feeding teeth (30) are driven to move, and the feeding teeth (30) are made to descend below the upper surface of the needle plate (120).

2. The sewing machine of claim 1, wherein: the tooth lifting mechanism (40) comprises a tooth lifting shaft (41) parallel to the main shaft (10), a first tooth lifting transmission component connected between the main shaft (10) and the tooth lifting shaft (41), and a second tooth lifting transmission component connected between the tooth lifting shaft (41) and the tooth frame (20), wherein the tooth lifting transmission component is one of the first tooth lifting transmission components.

3. The sewing machine of claim 2, wherein: the first feed lifting tooth transmission component comprises a feed lifting tooth eccentric wheel (42) fixed on the main shaft (10), a feed lifting tooth connecting rod (43), a feed lifting tooth swinging seat (44) with a first fixed swinging fulcrum O1, a first swinging plate (45), a second swinging plate (46) and a feed lifting tooth crank (47) fixed on a feed lifting tooth shaft (41), one end of the feed lifting connecting rod (43) is rotatably sleeved on the periphery of the feed lifting eccentric wheel (42), the other end of the feed lifting connecting rod (43), one end of the first swinging plate (45) and one end of the second swinging plate (46) are coaxially hinged, the other end of the first swinging plate (45) is hinged with the lifting tooth swinging seat (44), the other end of the second swinging plate (46) is hinged with a feed lifting crank (47), the lifting and pressing foot transmission component is connected with the lifting tooth swinging seat (44) through a lower supply transmission component (80); when the presser foot lifting driving source (70) drives the presser foot (60) to lift upwards through the presser foot lifting transmission assembly (90), the presser foot lifting transmission component drives the tooth lifting swing seat (44) to rotate around the first fixed swing fulcrum O1 through the lower supply transmission assembly (80).

4. The sewing machine of claim 3, wherein: the lower feeding transmission assembly (80) comprises a lower feeding pull rod (81), an adjusting crank (82) with a second fixed swing fulcrum O2 and an adjusting connecting rod (83), one end of the lower feeding pull rod (81) is hinged with the pressure lifting pin transmission component, the other end of the lower feeding pull rod is hinged with the adjusting connecting rod (83), and the adjusting connecting rod (83) is further hinged with the adjusting crank (82) and the tooth lifting swing seat (44) respectively.

5. The sewing machine of claim 4, wherein: still include adjust knob (84) and threaded connection adjusting stud (85) in the sewing machine casing, adjust knob (84) are fixed in the one end of adjusting stud (85), the other end of adjusting stud (85) with adjust crank (82) butt, can drive and adjust crank (82) and rotate around second fixed swing fulcrum O2.

6. The sewing machine of claim 5, wherein: a section of idle stroke section (811) is arranged in the lower supply pull rod (81), the lower supply pull rod (81) is hinged with the adjusting connecting rod (83) through a shaft position screw fixed on the adjusting connecting rod (83), and the shaft position screw is arranged in the idle stroke section (811) of the lower supply pull rod (81) in a penetrating manner; when the adjusting knob (84) drives the adjusting stud (85) to move, the shaft screw moves in the idle stroke section (811) of the lower supply rod (81).

7. The sewing machine of claim 4, wherein: the sewing machine further comprises a swinging seat return spring (50), and two ends of the swinging seat return spring (50) are respectively connected with the adjusting connecting rod (83) and the sewing machine shell.

8. The sewing machine of claim 2, wherein: the second tooth lifting transmission assembly comprises a sliding block (48) and a tooth lifting swing fork (49) fixed on a tooth lifting shaft (41), the sliding block (48) is hinged with the tooth frame (20), a sliding groove (491) is formed in the tooth lifting swing fork (49), and the sliding block (48) is located in the sliding groove (491) and is in sliding fit with the sliding groove.

9. The sewing machine of claim 1, wherein: the presser foot lifting transmission assembly (90) comprises a right lever (91) with a third fixed swing fulcrum O3, a presser foot lifting pull rod (92), a left lever (93) with a fourth fixed swing fulcrum O4, a presser foot lifting plate (94), a pressure lever guide frame (95) and a pressure lever (96) extending up and down, wherein the presser foot lifting drive source (70) is hinged with one end of the right lever (91) to drive the right lever (91) to rotate around the third fixed swing fulcrum O3, the other end of the right lever (91) is hinged with one end of the presser foot lifting pull rod (92), the other end of the presser foot lifting pull rod (92) is hinged with one end of the left lever (93), the other end of the left lever (93) is hinged with the upper end of the presser foot lifting plate (94), a lifting hook portion (941) is arranged on the presser foot lifting plate (94), and a connecting protrusion portion (951) clamped with the lifting hook portion (941) is arranged on the pressure lever guide frame (95), the pressure lever guide frame (95) is fixed at the upper end of a pressure lever (96), and the pressure foot (60) is arranged at the lower end of the pressure lever (96); the right lever (91) is connected with the tooth lifting transmission part through a lower supply transmission assembly (80).