CN112626728B - Sewing machine - Google Patents

Abstract

The invention provides a sewing machine, which comprises a main shaft, a feed lifting tooth shaft parallel to the main shaft, a tooth frame, a feeding tooth arranged on the tooth frame, a first feed lifting tooth transmission assembly connected between the main shaft and the feed lifting tooth shaft, a second feed lifting tooth transmission assembly connected between the feed lifting tooth shaft and the tooth frame, a lower feed driving source and a lower feed transmission assembly, wherein the lower feed driving source is connected with a transmission part in the first feed lifting tooth transmission assembly through the lower feed transmission assembly; when the sewing machine stops taking and placing sewing materials, a machine needle and a presser foot in the sewing machine are both positioned above a needle plate, a lower driving source acts, the lower driving source acts on a transmission component through a lower driving component, so that a feed lifting shaft rotates by an angle, the feed lifting shaft drives a tooth frame and feed teeth to move through a second feed lifting transmission component, and the feed teeth move down below the upper surface of the needle plate, so that the feed lifting teeth cannot influence the placement of the sewing materials on the needle plate, the sewing materials can be more conveniently fed and discharged, the sewing materials can be prevented from being scratched, and the sewing quality is ensured.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine.

Background

The existing sewing machine generally comprises a main shaft driven and rotated by the main shaft, a feed lifting tooth shaft and a feed delivery 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 delivery 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 delivery shaft through the first feed delivery transmission component, the feed delivery shaft is connected with the other end of the tooth frame through the second feed delivery 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 feed dog 300, when the needle 100 is located above the needle plate 400, the feed dog 300 also protrudes upwards from the tooth groove of the needle plate 400, that is, a part of the feed dog 300 is exposed upwards from the needle plate 400, and at this time, the sewing material 500 cannot be flatly placed on the needle plate 400; meanwhile, the feeding teeth 300 are protruded upwards from the needle plate 400, so that the sewing material is inconvenient to enter and exit, the sewing material is easy to scratch, the sewing quality is influenced, and the sewing experience is greatly reduced.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, it is an object of the present invention to provide a sewing machine that can achieve a needle and a presser foot both above a needle plate without a feed dog protruding upward from the needle plate when stopping taking and placing a sewing material.

In order to achieve the purpose, the invention provides a sewing machine, which comprises a main shaft, a feed lifting tooth shaft parallel to the main shaft, a tooth frame, a feed feeding tooth arranged on the tooth frame, a first feed lifting tooth transmission assembly connected between the main shaft and the feed lifting tooth shaft, a second feed lifting tooth transmission assembly connected between the feed lifting tooth shaft and the tooth frame, a lower feed driving source and a lower feed transmission assembly, wherein the lower feed driving source is connected with a transmission part in the first feed lifting tooth transmission assembly through the lower feed transmission assembly; when the sewing machine stops taking and placing sewing materials, a machine needle and a presser foot in the sewing machine are both positioned above a needle plate, the lower supply driving source acts on a transmission component through a lower supply transmission component to enable the feed lifting tooth shaft to rotate for an angle, and the feed lifting tooth shaft drives the tooth frame and the feed feeding tooth to move through the second feed lifting tooth transmission component to enable the feed feeding tooth to move downwards below the upper surface of the needle plate.

Furthermore, the first lifting tooth transmission assembly 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, wherein 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, and the other end of the second swinging plate is hinged with the lifting tooth crank; the lower supply driving source is connected with the tooth lifting swing seat through a lower supply transmission assembly; when the lower supply driving source acts, the lower supply driving source drives the lifting tooth swing seat to rotate around the first fixed swing fulcrum O1 through the lower supply transmission assembly.

Furthermore, the lower supply driving source is provided with a telescopic driving part, the lower supply transmission assembly comprises a lower supply pull rod support, a lower supply pull rod, an adjusting support shaft, a lower supply crank and an adjusting crank, the lower supply pull rod support is rotatably installed in the sewing machine shell, the lower supply crank and the adjusting crank are both fixed on the adjusting support shaft, one end of the lower supply pull rod support is fixed with the telescopic driving part, the other end of the lower supply pull rod is hinged with one end of the lower supply pull rod, the other end of the lower supply pull rod is hinged with the lower supply crank, and the adjusting crank is connected with the tooth lifting swing seat.

Furthermore, the adjusting crank is connected with the lifting tooth swinging seat through an adjusting connecting rod, and two ends of the adjusting connecting rod are respectively hinged with the adjusting crank and the lifting tooth swinging seat.

Furthermore, the sewing machine also comprises an adjusting rod movably arranged in the sewing machine shell and an adjusting operation part for driving the adjusting rod to move, and the adjusting rod is connected with the adjusting crank; the lower feed pull rod is internally provided with an idle stroke section, the lower feed pull rod and the lower feed crank are hinged through an axial position screw parallel to the feed lifting shaft, and the axial position screw penetrates through the idle stroke section of the lower feed pull rod; when the adjusting operation part drives the adjusting rod to move, the adjusting rod drives the lifting tooth swinging seat to rotate around a first fixed swinging fulcrum O1 through the adjusting crank, and the shaft position screw moves in the idle stroke section of the lower feed pull rod.

Furthermore, the adjusting rod is in butt fit with the adjusting crank.

Furthermore, the sewing machine further comprises a compression spring, one end of the compression spring is connected with the adjusting crank, and the other end of the compression spring is connected with 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 first sliding groove is formed in the tooth lifting swing fork, and the sliding block is located in the first sliding groove and is in sliding fit with the first sliding groove.

Furthermore, the sewing machine also comprises a presser foot, a presser foot lifting drive source and a presser foot lifting transmission assembly connected between the presser foot lifting drive source and the presser foot, wherein the presser foot lifting drive source and the lower supply drive source are the same drive source; when the sewing machine stops taking and placing sewing materials, the presser foot lifting driving source acts, the presser foot lifting driving source enables the presser foot to be lifted upwards through the presser foot lifting transmission assembly, and meanwhile the presser foot lifting driving source enables the feeding tooth to move downwards below the upper surface of the needle plate through the lower feeding transmission assembly, the transmission component, the tooth lifting shaft and the second tooth lifting transmission assembly.

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

this application stops to get when putting the sewing material at sewing machine, can realize that eedle and presser foot all upwards emerge in the top of faller, nevertheless pay-off tooth from the faller, so the pay-off tooth can not place the influence on the faller to the sewing material for the business turn over of sewing material becomes more convenient, and can also avoid the fish tail sewing material, thereby guarantees 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 and 5 are schematic views of connection among the main shaft, the first feed dog transmission assembly, the feed dog shaft, the lower feed drive source and the lower feed transmission assembly at different viewing angles in the application.

Fig. 6 is a schematic connection diagram of the main shaft, the first feed lifting teeth transmission assembly and the feed lifting teeth shaft in the application.

Fig. 7 is another embodiment of the connection structure of the adjusting lever and the adjusting crank in the present application.

Fig. 8 shows another embodiment of the connection structure of the adjusting crank and the lifting tooth swing seat in the application.

Fig. 9 is a schematic structural view of a lower supply link in the present application.

Fig. 10 is a schematic view of the structure of the lift and presser foot drive assembly of the present application.

Description of the element reference numerals

10 spindle

20 lifting tooth shaft

30 dental articulator

40 feeding tooth

50 first tooth lifting transmission assembly

51 eccentric cam of lifting tooth

52 lifting tooth connecting rod

53 lifting tooth swing seat

531 seat arm

532 second chute

54 first swinging plate

55 second swinging plate

56 lifting rock shaft crank

57 support pin

60 second feed dog transmission assembly

61 sliding block

62 lifting tooth swing fork

621 first chute

70 lower power supply source

71 telescoping drive part

80 lower supply transmission assembly

81 lower supply pull rod support

82 lower supply pull rod

821 idle stroke section

83 adjusting support shaft

84 lower supply crank

85 regulating crank

86 adjusting connecting rod

87 connecting sleeve

88 connecting 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

110 machine needle

120 presser foot

130 needle board

140 adjusting rod

150 regulating operation part

160 hold-down spring

170 presser foot reset spring

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 and 3, 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 in the views of fig. 2 and 3), 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 in the views of fig. 2 and 3); 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 application includes a main shaft 10 extending left and right, a thread frame 30, a feed dog 40 installed on the thread frame 30, a feed mechanism connected between the main shaft 10 and the front end of the feed dog 40, a feed lifting mechanism connected between the main shaft 10 and the rear end of the feed dog 40, a needle plate 130, a presser foot 120, a needle bar extending up and down, a machine needle 110 installed at the lower end of the needle bar, and a needle bar transmission assembly connected between the main shaft 10 and the needle bar; the tooth lifting mechanism comprises a tooth lifting shaft 20 parallel to the main shaft 10, a first tooth lifting transmission assembly 50 connected between the main shaft 10 and the tooth lifting shaft 20, and a second tooth lifting transmission assembly 60 connected between the tooth lifting shaft 20 and the tooth frame 30; 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 a spreading way. Specifically, as shown in fig. 2 and 3, the sewing machine further includes a lower supply driving source 70 and a lower supply transmission assembly 80, and the lower supply driving source 70 is connected to a transmission member in the first feed dog transmission assembly 50 through the lower supply transmission assembly 80.

When the sewing machine related to the application is used for normal sewing, the lower supply driving source 70 does not act, under the limiting action of the lower supply driving source 70 and the lower supply transmission assembly 80, a transmission part connected with the lower supply transmission assembly 80 in the first feed lifting tooth transmission assembly 50 is kept at an angle, the main shaft 10 is driven by the main motor to rotate, the main shaft 10 drives the tooth frame 30 and the feed lifting teeth 40 to reciprocate back and forth through the feed mechanism, the main shaft 10 drives the tooth frame 30 and the feed lifting teeth 40 to reciprocate up and down through the feed lifting tooth mechanism, so that the feed lifting teeth 40 do periodic compound motion of back and forth reciprocating motion and up and down reciprocating motion, and the motion track of the feed lifting teeth 40 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 40 move in a matched mode to realize sewing of sewing materials. Particularly, when the sewing machine stops operating to take the sewn sewing material from the needle plate 130 or put the sewing material to be sewn on the needle plate 130, at this time, a hand wheel fixed at the right end of the main shaft 10 is rotated to make the needle 110 be positioned above the needle plate 130, and simultaneously, the presser foot 120 is lifted upwards to make the presser foot 120 be positioned above the needle plate 130; the lower supply driving source 70 is also operated, the lower supply driving source 70 operates the transmission component in the first feed dog transmission assembly 50 through the lower supply transmission assembly 80, the feed dog shaft 20 rotates through an angle through the transmission component, the feed dog shaft 20 drives the tooth rack 30 and the feed dog 40 to move through the second feed dog transmission assembly 60, and the feed dog 40 moves downwards to be below the upper surface of the needle plate 130, at this time, the upper surface of the feed dog 40 is flush with the upper surface of the needle plate 130, or the upper surface of the feed dog 40 is positioned below the upper surface of the needle plate 130. Therefore, this application stops to get when putting the sewing material at sewing machine and reduces the height of pay-off tooth 40 automatically, with pay-off tooth 40 automatic decline to below the upper surface of faller 130, can realize that eedle 110 and presser foot 120 are all in the top of faller 130, nevertheless pay-off tooth 40 does not upwards emerge from faller 130, so pay-off tooth 40 can not place the sewing material and produce the influence on faller 130, make the business turn over of sewing material become more convenient, and can also avoid fish tail sewing material, thereby guarantee the sewing quality, promote user experience degree greatly.

As shown in fig. 4 to 6, the first lifting tooth transmission assembly 50 includes a lifting tooth eccentric wheel 51 fixed to the main shaft 10 by a screw, a lifting tooth connecting rod 52, a lifting tooth swinging seat 53 having a first fixed swinging fulcrum O1, a first swinging plate 54, a second swinging plate 55, and a lifting tooth crank 56 fixed to the lifting tooth shaft 20 by a screw, wherein the upper end of the lifting tooth connecting rod 52 is rotatably fitted around the periphery of the lifting tooth eccentric wheel 51, the lower end of the lifting tooth connecting rod 52, the front end of the first swinging plate 54, and the front end of the second swinging plate 55 are coaxially hinged by a pin extending left and right, the rear end of the first swinging plate 54 is hinged to the lifting tooth swinging seat 53 by a pin extending left and right, and the rear end of the second swinging plate 55 is hinged to the lifting tooth crank 56 by a pin extending left and right. The lower supply driving source 70 is connected with the tooth lifting swing seat 53 through a lower supply transmission assembly 80; when the lower supply driving source 70 acts, the lower supply driving source 70 drives the lifting tooth swinging seat 53 to rotate around the first fixed swinging fulcrum O1 through the lower supply transmission assembly 80, the position angle of the lifting tooth swinging seat 53 is changed, so that the lifting tooth shaft 20 rotates for an angle, the lifting tooth shaft 20 drives the tooth frame 30 and the feeding tooth 40 to move through the second lifting tooth transmission assembly 60, the feeding tooth 40 moves downwards to be lower than the upper surface of the needle plate 130, and the problem that the feeding tooth 40 is exposed upwards from the needle plate 130 during sewing so as to be inconvenient to discharge is solved.

Preferably, as shown in fig. 6, the lift tooth swing seat 53 has two seat arm portions 531 arranged bilaterally symmetrically, two first swing plates 54 and two second swing plates 55 are both positioned between the two seat arm portions 531, the two second swing plates 55 are distributed on the left and right sides of the lower end of the lift tooth link 52, and one first swing plate 54 is distributed between the first swing plate 54 and the seat arm portions 531. Each of the seat arm portions 531 is rotatably mounted to a support pin 57 extending left and right, and the support pin 57 is fixed to the sewing machine housing and constitutes a first fixed swing fulcrum O1 of the lifter swing seat 53.

As shown in fig. 2 and 3, the second tooth lifting transmission assembly 60 includes a sliding block 61 and a tooth lifting swing fork 62 fixed on the tooth lifting shaft 20 by a screw, the sliding block 61 is hinged with the tooth frame 30 by a pin extending left and right, a first sliding slot 621 is formed in the tooth lifting swing fork 62, the sliding block 61 is located in the first sliding slot 621, and the two are in sliding fit. Preferably, the sliding block 61 is in surface contact with the groove wall of the first sliding groove 621.

As shown in fig. 2 to 5, the lower supply driving source 70 has a telescopic driving portion 71 which can be vertically telescopic, so that the lower supply driving source 70 can be selected from an electromagnet, a linear motor, an air cylinder, and the like; in the present embodiment, the lower supply drive source 70 is preferably an electromagnet. The preferred construction of the lower feed drive assembly 80 is: the lower supply transmission assembly 80 includes a lower supply tension rod support 81, a lower supply tension rod 82, an adjusting support shaft 83 rotatably installed in the sewing machine housing, and a lower supply crank 84 and an adjusting crank 85 both fixed to the adjusting support shaft 83 by screws; the adjusting support shaft 83 is parallel to the feed lifting rock shaft 20, extends leftwards and rightwards, is provided with a crank 84 and an adjusting crank 85 in parallel left and right, and forms a second fixed swinging fulcrum O2 of the adjusting crank 85; the upper end of the lower supply pull rod bracket 81 is fixed on an electromagnet core joint, the electromagnet core joint and the electromagnet core are fixed, and the electromagnet core joint and the electromagnet core form a telescopic driving part 71 of the lower supply driving source 70, so that the upper end of the lower supply pull rod bracket 81 is fixed with the telescopic driving part 71; the lower end of the lower supply pull rod bracket 81 is hinged with the upper end of the lower supply pull rod 82 through a pin extending left and right, and the lower end of the lower supply pull rod 82 is hinged with the lower supply crank 84 through a shaft position screw extending left and right; the adjusting crank 85 is connected with the lifting tooth swinging seat 53. When the sewing machine sews normally, the electromagnet is in the power-off state, and the position angle of the lifting tooth swinging seat 53 is fixed; when the sewing machine stops to take and place sewing materials, the electromagnet is electrified, the iron core and the iron core joint of the electromagnet move upwards together, the lower supply pull rod support 81 and the lower supply pull rod 82 drive the lower supply crank 84 to swing, the lower supply crank 84 drives the adjusting support shaft 83 and the adjusting crank 85 to rotate around the adjusting support shaft 83 for an angle, the adjusting crank 85 drives the feed lifting tooth swing seat 53 to rotate around the first fixed swing fulcrum O1 for an angle, and the feed feeding tooth 40 moves downwards to be below the upper surface of the needle plate 130.

Further, the connection between the adjustment crank 85 and the lifting tooth swing seat 53 is preferably performed in two ways: firstly, as shown in fig. 2 to 5, the adjusting crank 85 is connected to the swing seat 53 through an adjusting link 86, the upper end of the adjusting link 86 is hinged to the adjusting crank 85 through a pin extending left and right, and the lower end of the adjusting link 86 is hinged to the swing seat 53 through a pin extending left and right. In the second mode, as shown in fig. 8, the adjusting crank 85 is hinged to the lifting teeth swinging seat 53 through a connecting pin 88 extending left and right, a second sliding slot 532 is formed in a seat arm 531 of the lifting teeth swinging seat 53, and the connecting pin 88 is located in the second sliding slot 532 and is in sliding fit with the second sliding slot 532.

Further, the sewing machine according to the present application can also adjust the feed dog height of the feed dog 40, and the feed dog height of the feed dog 40 is a distance from the upper surface of the needle plate 130 when the feed dog 40 moves to the highest point. The preferred regulating structure is: as shown in fig. 2 to 5, the sewing machine further includes an adjusting lever 140 movably installed in the sewing machine frame, and an adjusting operation part 150 driving the adjusting lever 140 to move, the adjusting lever 140 being connected to the adjusting crank 85; as shown in fig. 9, a section of idle stroke 821 is provided in the lower supply link 82, and a shaft screw for hinging the lower supply link 82 and the lower supply crank 84 is inserted into the idle stroke 821 of the lower supply link 82, and the idle stroke 821 is an idle groove extending along the extending direction of the lower supply link 82. Preferably, the adjusting rod 140 is perpendicular to the main shaft 10 and extends back and forth along the direction of the feeding tooth 40 for transferring the sewing material forward; the adjusting lever 140 is a screw threadedly coupled in the sewing machine housing, and the adjusting operation part 150 is a knob fixed to the rear end of the adjusting lever 140. When the height of the feed lifting teeth is adjusted, a knob forming the adjusting operation part 150 is rotated, the knob drives the adjusting rod 140 to rotate together, the adjusting rod 140 moves forwards or backwards relative to the sewing machine shell when rotating, and then the adjusting crank 85 is driven to rotate around the adjusting support shaft 83 by an angle, the adjusting crank 85 can drive the feed lifting teeth swinging seat 53 to rotate around the first fixed swinging fulcrum O1 by an angle, the position angle of the feed lifting teeth swinging seat 53 is changed, so that the swinging amplitude of the feed lifting teeth swinging seat 20 driven by the main shaft 10 through the first feed lifting teeth transmission assembly 50 during subsequent sewing is changed, the moving amplitude of the feed lifting teeth 40 driven by the main shaft 10 through the second feed lifting teeth transmission assembly 60 to reciprocate up and down is changed, and the adjustment of the feed lifting teeth height of the feed lifting teeth 40 is realized. During the adjustment of the height of the feed dog 40, the adjustment crank 85 is rotated by the forward and backward movement of the adjustment rod 140, the adjustment support shaft 83 and the lower supply crank 84 rotate together with the adjustment crank 85, and the axial screws for hinging the lower supply pull rod 82 and the lower supply crank 84 move in the idle stroke segment 821 of the lower supply pull rod 82, so that the rotation of the lower supply crank 84 does not push the lower supply pull rod 82 to move, i.e., the lower supply pull rod 82 does not move during the adjustment of the height of the feed dog 40.

In particular, the sewing machine according to the present application adjusts the feed dog height of the feed dog 40 by changing the swing of the feed dog shaft 20, and the feed dog height adjusting device can make the movement track of the feed dog 40 change in an equal ratio only in the vertical direction relative to the upper surface of the needle plate 130, and does not make the movement track of the feed dog 40 move up or down as a whole, so that the needle pitch of the sewing machine is kept unchanged during the feed dog height adjusting process, and the sewing quality is not affected, and the phenomenon that the feed dog 40 drags back the sewing material does not occur. Therefore, the height of the feed dog 40 can be adjusted within a certain range, the feed dog is in stepless adjustment, 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 sewing materials of the sewing machine is improved, the universality of the sewing machine is greatly improved, and the competitiveness of products is improved.

Further, the adjusting lever 140 and the adjusting crank 85 are preferably connected in two ways: in the first mode, as shown in fig. 2 to 5, the front end of the adjusting rod 140 abuts against the rear end of the adjusting crank 85, that is, the adjusting rod 140 abuts against and is matched with the adjusting crank 85; at this time, the sewing machine further comprises a pressing spring 160, the upper end of the pressing spring 160 is connected with the adjusting crank 85, and the lower end of the pressing spring 160 is connected with a fixed point in the sewing machine shell; the pressing spring 160 exerts acting force on the adjusting crank 85, so that the abutting reliability between the adjusting crank 85 and the front end part of the adjusting rod 140 is ensured, the adjusting crank 85 and the adjusting rod can be reliably abutted and matched, and the adjusting accuracy of the tooth lifting height is ensured; in this embodiment, the pressing spring 160 is a tension spring. Secondly, as shown in fig. 7 and 8, the adjusting rod 140 is connected with the adjusting crank 85 through a connecting sleeve 87, the connecting sleeve 87 is rotatably installed at the front end of the adjusting rod 140, and the adjusting rod 140 and the connecting sleeve 87 can rotate relatively but cannot move relatively; the front end of the connecting sleeve 87 is provided with a notch, the upper end of the adjusting crank 85 is positioned in the notch of the connecting sleeve 87 and is provided with a third sliding groove, the upper end of the adjusting crank 85 is hinged with the front end of the connecting sleeve 87 through a pin extending left and right, and the pin penetrates through the third sliding groove and is in sliding fit with the third sliding groove. When the adjusting lever 140 moves in the front-rear direction, the connecting sleeve 87 is driven to move together, and the adjusting crank 85 is driven to rotate around the second fixed swing fulcrum O2 by the connecting sleeve 87.

Further, as shown in fig. 2 and 3, the sewing machine further includes a presser foot lifting drive source and a presser foot lifting transmission assembly 90 connected between the presser foot lifting drive source and the presser foot 120, and when the presser foot lifting drive source operates, the presser foot lifting transmission assembly 90 drives the presser foot 120 to lift upwards, so that automatic presser foot lifting is realized. The preferred structure of the presser foot lifting transmission assembly 90 is: as shown in fig. 10, the lift and press foot drive assembly 90 includes a right lever 91 having a third fixed pivot point O3, a lift and press foot lever 92, a left lever 93 having a fourth fixed pivot point O4, the lifting presser foot lifting plate 94, the pressing rod guide frame 95 and the pressing rod 96 extending up and down are hinged to a shell of the sewing machine through shaft position screws extending back and forth, an iron core joint of an electromagnet is hinged to the right end of the right lever 91, the left end of the right lever 91 is hinged to the right end of the presser foot lifting pull rod 92, the left end of the presser foot lifting pull rod 92 is hinged to the upper right end of the left lever 93, the lower left end of the left lever 93 is hinged to the upper end of the presser foot lifting plate 94, the presser foot lifting plate 94 is provided with a lifting hook portion 941, the pressing rod guide frame 95 is provided with a connecting protrusion portion 951 clamped with the lifting hook portion 941, the pressing rod guide frame 95 is fixed to the upper end of the pressing rod 96, and the presser foot 120 is installed at the lower end of the pressing rod 96. As shown in fig. 3, a presser foot return spring 170 is fitted over the presser bar 96.

Further, as shown in fig. 2 and 3, the presser foot raising drive source and the lower supply drive source 70 are the same drive source and the same electromagnet. Therefore, when the sewing machine stops taking and placing sewing materials, the presser foot lifting driving source acts, the presser foot lifting driving source enables the presser foot 120 to be lifted upwards through the presser foot lifting transmission assembly 90, meanwhile, the presser foot lifting driving source enables the feeding teeth 40 to move downwards below the upper surface of the needle plate 130 through the lower feeding transmission assembly 80, the transmission component, the tooth lifting shaft 20 and the second tooth lifting transmission assembly 60, the feeding teeth 40 are automatically lowered below the upper surface of the needle plate 130 in the process of automatically lifting the presser foot, the problem that the feeding teeth 40 are exposed upwards from the needle plate 130 to be inconvenient to take and place materials is effectively solved, user experience is greatly improved, and product competitiveness is improved.

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 compression spring 160 enables the front end of the adjusting rod 140 to be always abutted against the adjusting crank 85, the feed lifting tooth swinging seat 53 is in a static state and is kept at a fixed position angle, the main shaft 10 drives the feed lifting tooth shaft 20 to do periodic reciprocating swinging through the first transmission component, the feed lifting tooth shaft 20 drives the tooth frame 30 and the feed lifting tooth 40 to do periodic up-and-down reciprocating movement through the second transmission component, and the amplitude of the up-and-down reciprocating movement of the feed lifting tooth 40 is related to the swinging amplitude of the feed lifting tooth shaft 20.

When the sewing machine stops, the needle 110 moves above the needle plate 130, and because of the synchronous linkage relationship between the needle 110 and the feed dog 40, the feed dog 40 also moves above the needle plate 130 when the electromagnet is not energized. When the material is required to be taken or discharged, the electromagnet is electrified, the iron core of the electromagnet moves upwards and extends out to drive the iron core joints to move upwards together, and the iron core joints of the electromagnet drive the presser foot 120 to be lifted upwards through the presser foot lifting transmission assembly 90; meanwhile, the electromagnet drives the lower supply crank 84 and the adjusting crank 85 to rotate for an angle through the lower supply pull rod bracket 81 and the lower supply pull rod 82, the adjusting crank 85 rotates towards the direction far away from the adjusting rod 140, the adjusting crank 85 drives the lifting tooth swinging seat 53 to swing for an angle, and the lifting tooth swinging seat 53 directly controls the lifting tooth height of the feeding tooth 40, so that the feeding tooth 40 is promoted to descend below the upper surface of the needle plate 130, and the material taking and discharging are further facilitated. Then, when the sewing machine starts sewing, the electromagnet is powered off, the presser foot 120 descends to the needle plate 130 under the action of the presser foot return spring 170, and the lifting tooth swing seat 53 is returned under the action of the pressing spring 160 and abuts against the front end of the adjusting rod 140. Therefore, the feeding teeth 40 are automatically descended below the upper surface of the needle plate 130 in the process of automatically 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 40 in the normal sewing of the subsequent sewing machine is not changed.

When the height of the feed lifting teeth 40 needs to be adjusted, the knob is rotated to drive the adjusting rod 140 to move forwards or backwards, so that the adjusting crank 85 is driven to swing, the position angle of the feed lifting teeth swinging seat 53 is changed, the swinging amplitude of the feed lifting teeth shaft 20 driven by the main shaft 10 through the first feed lifting teeth transmission assembly 50 during subsequent sewing is changed, and the height of the feed lifting teeth 40 is adjusted. Meanwhile, the axial screws for hinging the lower supply pull rod 82 and the lower supply crank 84 move in the idle stroke section 821 of the lower supply pull rod 82, so that the pressure foot lifting transmission assembly 90 does not act when the height of the lifting tooth of the feeding tooth 40 is adjusted, and the height state of the pressure foot 120 is not changed.

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 (6)

1. A sewing machine comprises a main shaft (10), a feed lifting tooth shaft (20) parallel to the main shaft (10), a tooth frame (30), a feed lifting tooth (40) arranged on the tooth frame (30), a first feed lifting tooth transmission assembly (50) connected between the main shaft (10) and the feed lifting tooth shaft (20), and a second feed lifting tooth transmission assembly (60) connected between the feed lifting tooth shaft (20) and the tooth frame (30), and is characterized in that: the lower feed driving source (70) and the lower feed transmission assembly (80) are further included, and the lower feed driving source (70) is connected with a transmission part in the first tooth lifting transmission assembly (50) through the lower feed transmission assembly (80); when the sewing machine stops taking and placing sewing materials, a needle (110) and a presser foot (120) in the sewing machine are both positioned above a needle plate (130), the lower supply driving source (70) acts on a transmission component through a lower supply transmission assembly (80) to enable the feed lifting tooth shaft (20) to rotate for an angle, and the feed lifting tooth shaft (20) drives the tooth frame (30) and the feed lifting tooth (40) to move through a second feed lifting tooth transmission assembly (60) to enable the feed lifting tooth (40) to move downwards below the upper surface of the needle plate (130);

the first lifting tooth transmission assembly (50) comprises a lifting tooth eccentric wheel (51) fixed on the main shaft (10), a lifting tooth connecting rod (52), a lifting tooth swinging seat (53) with a first fixed swinging fulcrum O1, a first swinging plate (54), a second swinging plate (55) and a lifting tooth crank (56) fixed on the lifting tooth shaft (20), one end of the lifting tooth connecting rod (52) is rotatably sleeved on the periphery of the lifting tooth eccentric wheel (51), the other end of the lifting tooth connecting rod (52), one end of the first swinging plate (54) and one end of the second swinging plate (55) are coaxially hinged, the other end of the first swinging plate (54) is hinged with the lifting tooth swinging seat (53), and the other end of the second swinging plate (55) is hinged with the lifting tooth crank (56); the lower supply driving source (70) is connected with the tooth lifting swing seat (53) through a lower supply transmission assembly (80); when the lower supply driving source (70) acts, the lower supply driving source (70) drives the tooth lifting swing seat (53) to rotate around a first fixed swing fulcrum O1 through a lower supply transmission assembly (80);

the lower supply driving source (70) is provided with a telescopic driving part (71), the lower supply transmission assembly (80) comprises a lower supply pull rod support (81), a lower supply pull rod (82), an adjusting support shaft (83) rotatably installed in a sewing machine shell, and a lower supply crank (84) and an adjusting crank (85) which are both fixed on the adjusting support shaft (83), one end of the lower supply pull rod support (81) is fixed with the telescopic driving part (71), the other end of the lower supply pull rod (82) is hinged with one end of the lower supply pull rod (82), the other end of the lower supply pull rod (82) is hinged with the lower supply crank (84), and the adjusting crank (85) is connected with the tooth lifting swing seat (53);

the sewing machine further comprises an adjusting rod (140) movably arranged in the sewing machine shell and an adjusting operation part (150) driving the adjusting rod (140) to move, wherein the adjusting rod (140) is connected with an adjusting crank (85); a section of idle stroke section (821) is arranged in the lower supply pull rod (82), the lower supply pull rod (82) and the lower supply crank (84) are hinged through a shaft position screw parallel to the feed lifting screw shaft (20), and the shaft position screw penetrates through the idle stroke section (821) of the lower supply pull rod (82); when the adjusting operation part (150) drives the adjusting rod (140) to move, the adjusting rod (140) drives the lifting tooth swinging seat (53) to rotate around a first fixed swinging fulcrum O1 through the adjusting crank (85), and the shaft position screw moves in an idle stroke section (821) of the lower supply pull rod (82).

2. The sewing machine of claim 1, wherein: the adjusting crank (85) is connected with the lifting tooth swinging seat (53) through an adjusting connecting rod (86), and two ends of the adjusting connecting rod (86) are respectively hinged with the adjusting crank (85) and the lifting tooth swinging seat (53).

3. The sewing machine of claim 1, wherein: the adjusting rod (140) is in butt fit with the adjusting crank (85).

4. The sewing machine of claim 3, wherein: the sewing machine further comprises a pressing spring (160), wherein one end of the pressing spring (160) is connected with the adjusting crank (85), and the other end of the pressing spring (160) is connected with the sewing machine shell.

5. The sewing machine of claim 1, wherein: the second tooth lifting transmission assembly (60) comprises a sliding block (61) and a tooth lifting swing fork (62) fixed on a tooth lifting shaft (20), the sliding block (61) is hinged with the tooth frame (30), a first sliding groove (621) is formed in the tooth lifting swing fork (62), and the sliding block (61) is located in the first sliding groove (621) and in sliding fit with the first sliding groove (621).

6. The sewing machine of claim 1, wherein: the device also comprises a presser foot (120), a presser foot lifting driving source and a presser foot lifting transmission assembly (90) connected between the presser foot lifting driving source and the presser foot (120), wherein the presser foot lifting driving source and the lower supply driving source (70) are the same driving source; when the sewing machine stops taking and placing sewing materials, the presser foot lifting driving source acts, the presser foot lifting driving source enables the presser foot (120) to be lifted upwards through the presser foot lifting transmission assembly (90), and meanwhile the presser foot lifting driving source enables the feeding tooth (40) to move downwards to the position below the upper surface of the needle plate (130) through the lower feeding transmission assembly (80), the transmission component, the feed lifting tooth shaft (20) and the second feed lifting transmission assembly (60).

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