CN114481460B - Flush joint machine - Google Patents

Abstract

The invention provides a flush joint machine, which comprises a main shaft, a tooth rack, feeding teeth, a tooth lifting mechanism, a feeding mechanism, a presser foot lifting mechanism, a driving source, a presser foot lifting driving piece and a needle pitch adjusting driving piece which are driven by the driving source to rotate, a presser foot lifting transmission unit connected between the presser foot lifting driving piece and the presser foot lifting mechanism, a needle pitch adjusting transmission unit connected between the needle pitch adjusting driving piece and a feeding swing seat, a lower supply pull rod and a tooth lifting height adjusting unit, wherein the lower supply pull rod is connected with the lower supply pull rod; the tooth lifting mechanism is provided with a tooth lifting swing seat which determines the height of the tooth lifting; the feeding mechanism is provided with a feeding swing seat for determining the needle pitch; two ends of the lower supply pull rod are respectively hinged with a transmission component in the pressure foot lifting transmission unit and the tooth lifting swing seat; the lifting tooth height adjusting unit is used for changing the angle of the lifting tooth swinging seat. The automatic feed dog lifting mechanism realizes that the same driving source is adopted to drive the pressure foot lifting and the needle distance adjusting, the height of the lifting dog is adjustable, and the feed dog automatically falls below the upper surface of the needle plate when the pressure foot is lifted, so that the performance of the flat sewing machine is effectively improved.

Description

Flush joint machine

Technical Field

The invention relates to the field of sewing machines, in particular to a flat sewing machine.

Background

The existing lockstitch sewing machines are all provided with a presser foot lifting mechanism, a feed tooth lifting mechanism for driving feed teeth to reciprocate up and down, a feed mechanism for driving the feed teeth to reciprocate back and forth and the like. During sewing, the main shaft is driven by the main motor to rotate, the main shaft drives the tooth frame and the feeding teeth fixed on the tooth frame to do reciprocating motion back and forth in the horizontal direction through the feeding mechanism, the main shaft drives the tooth frame and the feeding teeth fixed on the tooth frame to do reciprocating motion up and down in the vertical direction through the tooth lifting mechanism, so that the feeding teeth do compound motion of the reciprocating motion back and forth and the reciprocating motion up and down, and the motion track of the feeding teeth is similar to an ellipse. Before sewing starts and when sewing is finished, the presser foot lifting mechanism automatically lifts the presser foot, and the presser foot is lifted upwards.

Further, as shown in fig. 1, the feed lifting mechanism in the existing lockstitch sewing machine includes a feed lifting shaft 200 parallel to the main shaft 100, a feed lifting eccentric 300 fixed on the main shaft 100, a feed lifting crank 400 and a feed lifting fork 500 both fixed on the feed lifting shaft 200, a feed lifting connecting rod 600, and a feed lifting slider 800 hinged to the feed lifting frame 700, wherein the feed lifting connecting rod 600 is rotatably fitted to the feed lifting eccentric 300 at an upper end thereof, and is hinged to the feed lifting crank 400 at a lower end thereof, and the feed lifting slider 800 is located in a sliding groove of the feed lifting fork 500 and is slidably fitted thereto. In addition, the main shaft 100 drives the needle to reciprocate up and down through the needle bar mechanism, so that the needle and the feeding tooth are in synchronous linkage. However, the existing flat sewing machine has the following defects in practical use:

1. when the lockstitch sewing machine stops to discharge materials, as shown in fig. 2, in order to ensure that the sewing materials 1400 are normally placed below the presser foot 1100 and on the needle plate 1300, a needle 900 and the presser foot 1100 in the lockstitch sewing machine are both required to be positioned above the needle plate 1300, the presser foot 1100 is driven to be lifted by a presser foot lifting mechanism in the lockstitch sewing machine, and the needle 900 is driven to move to the highest point by an operator through rotating a hand wheel fixed at the end part of a main shaft. However, due to the synchronous linkage relationship between the needle 900 and the feeding teeth 1200, when the needle 900 is located above the needle plate 1300, the feeding teeth 1200 also protrude upwards from the tooth grooves of the needle plate 1300, that is, a part of the feeding teeth 1200 is exposed upwards to the needle plate 1300, so that the distance between the presser foot 1100 which is originally not wide and abundant and the needle plate 1300 becomes narrower, thereby causing very labored discharging during thick material sewing, and the feeding teeth 1200 are easy to scrape some special sewing materials 1400, and the phenomenon that the sewing materials 1400 are staggered and layered due to the friction force between the feeding teeth 1200 and the sewing materials 1400 during discharging, thereby greatly reducing the sewing quality.

2. The tooth lifting height (namely the distance from the feeding tooth to the upper surface of the needle plate when the feeding tooth moves to the highest point) of the flat sewing machine is a fixed value and is set according to the assembling process of machine types. However, different feed materials in the market need to be sewn by using different feed lifting tooth heights, so that the stitch effect which is satisfied by customers can be achieved. Obviously, the flat sewing machine with the fixed lifting tooth height cannot meet the requirement, and the sewing material adaptability is poor.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a lockstitch sewing machine which uses the same driving source to drive the presser foot lifting and the needle pitch adjustment, and simultaneously realizes the adjustment of the height of the feed lifting teeth and the automatic lowering of the feed feeding teeth below the upper surface of the needle plate when the presser foot is lifted.

In order to achieve the purpose, the invention provides a flush joint machine, which comprises a main shaft, a tooth rack, feeding teeth fixed on the tooth rack, a tooth lifting mechanism connected between the main shaft and one end of the tooth rack, a feeding mechanism connected between the main shaft and the other end of the tooth rack, a presser foot lifting mechanism connected with the presser foot, a driving source, a presser foot lifting driving piece and a needle pitch adjusting driving piece which are driven by the driving source to rotate, a presser foot lifting transmission unit connected between the presser foot lifting driving piece and the presser foot lifting mechanism, a needle pitch adjusting transmission unit connected between the needle pitch adjusting driving piece and a feeding swing seat, a lower supply pull rod and a tooth lifting height adjusting unit; the tooth lifting mechanism is provided with a tooth lifting swing seat capable of rotating around a first fixed swing fulcrum, and the angle of the tooth lifting swing seat determines the tooth lifting height of the lockstitch sewing machine; the feeding mechanism is provided with a feeding swing seat capable of rotating around a second fixed swing fulcrum, and the angle of the feeding swing seat determines the needle pitch of the flat sewing machine; two ends of the lower supply pull rod are respectively hinged with a transmission component in the pressure foot lifting transmission unit and the tooth lifting swing seat; the lifting tooth height adjusting unit acts on the lifting tooth swinging seat and is used for changing the angle of the lifting tooth swinging seat;

when the presser foot is automatically lifted, the driving source drives the presser foot lifting driving piece and the needle pitch adjusting driving piece to rotate, power is transmitted between the presser foot lifting driving piece and the presser foot lifting transmission unit, the presser foot lifting driving piece drives the presser foot lifting mechanism to act through the presser foot lifting transmission unit, so that the presser foot is lifted upwards, and meanwhile, a transmission component in the presser foot lifting transmission unit drives the tooth lifting swing seat to rotate around a second fixed swing fulcrum through a lower supply pull rod, so that the feeding tooth is automatically lowered below the upper surface of a needle plate in the flat sewing machine;

when the stitch length is adjusted, the driving source drives the presser foot lifting driving piece and the stitch length adjusting driving piece to rotate, no power is transmitted between the presser foot lifting driving piece and the presser foot lifting transmission unit, and the stitch length adjusting driving piece drives the feeding swing seat to rotate around the first fixed swing fulcrum through the stitch length adjusting transmission unit to change the stitch length of the flat sewing machine.

Further, the driving source is a motor, and the pressure lifting and pressing foot driving part and the needle pitch adjusting driving part are both fixed on a motor shaft of the driving source.

Furthermore, the needle pitch adjusting driving part is an eccentric wheel for adjusting needle pitch, the needle pitch adjusting transmission unit comprises a connecting rod for adjusting needle pitch, one end of the connecting rod for adjusting needle pitch is rotatably sleeved on the periphery of the eccentric wheel for adjusting needle pitch, and the other end of the connecting rod for adjusting needle pitch is hinged with the feeding swing seat.

Furthermore, the presser foot lifting driving part is a presser foot lifting cam, and the outer peripheral surface of the presser foot lifting cam is provided with a presser foot lifting driving section which is a diameter-variable surface and an idle stroke section which is an equal-diameter surface; the presser foot lifting transmission unit comprises a transmission lever capable of rotating around a third fixed swing fulcrum, a roller wheel rotatably arranged at one end of the transmission lever, and a transmission pull rod, wherein two ends of the transmission pull rod are respectively hinged with the other end of the transmission lever and a right lever rod in the presser foot lifting mechanism, and the lower supply pull rod is hinged with the transmission lever; when the presser foot is lifted automatically, the roller is in contact fit with a presser foot lifting driving section of the presser foot lifting cam; when the needle pitch is adjusted, the idler wheel is in contact fit with the idle stroke section of the pressure raising and pressing foot cam.

Further, the presser foot lifting mechanism comprises a right lever capable of rotating around a fourth fixed swing fulcrum, a presser foot lifting pull rod, a left lever capable of rotating around a fifth fixed swing fulcrum, a presser foot lifting plate, a press rod guide frame and a press rod extending up and down, the right lever is hinged with one end of the presser foot lifting pull rod, the other end of the presser foot lifting pull rod is hinged with one end of the left lever, the other end of the left lever is hinged with the upper end of the presser foot lifting plate, a lifting hook part is arranged on the presser foot lifting plate, a connecting protrusion part clamped with the lifting hook part is arranged on the press rod guide frame, the press rod guide frame is fixed at the upper end of the press rod, and the presser foot is arranged at the lower end of the press rod.

Furthermore, the lower pull supply rod is hinged with the transmission lever through an axial screw parallel to the main shaft, an avoidance groove extending along the length direction of the lower pull supply rod is formed in the lower pull supply rod, and the axial screw penetrates through the avoidance groove of the lower pull supply rod; when the lifting tooth height adjusting unit changes the angle of the lifting tooth swinging seat, the avoiding groove moves relative to the axial position screw.

Furthermore, the tooth lifting mechanism also comprises a tooth lifting shaft parallel to the main shaft, a first tooth lifting transmission unit connected between the main shaft and the tooth lifting shaft, and a second tooth lifting transmission unit connected between the tooth lifting shaft and the tooth frame; the first feed lifting tooth transmission unit comprises a feed lifting tooth eccentric wheel fixed on the main shaft, a feed lifting tooth connecting rod, a chute arranged in the feed lifting tooth swinging seat, a transmission sliding block in sliding fit with the chute, a transmission connecting rod and a feed lifting tooth crank fixed on the feed lifting tooth shaft, wherein the upper end of the feed lifting tooth connecting rod is rotatably sleeved on the periphery of the feed lifting tooth eccentric wheel, the lower end of the feed lifting tooth connecting rod, the transmission sliding block and one end of the transmission connecting rod are coaxially hinged, and the other end of the transmission connecting rod is hinged with the feed lifting tooth crank.

Furthermore, two groups of sliding chutes and two groups of transmission sliding blocks which are in sliding fit are arranged and are distributed on two sides of the feed lifting tooth connecting rod in the axial direction of the feed lifting tooth shaft, a connecting groove is further formed in the lower end of the feed lifting tooth connecting rod, and the end part of the transmission connecting rod is located in the connecting groove in the lower end of the feed lifting tooth connecting rod.

Furthermore, the tooth lifting mechanism also comprises a tooth lifting shaft parallel to the main shaft, a first tooth lifting transmission unit connected between the main shaft and the tooth lifting shaft, and a second tooth lifting transmission unit connected between the tooth lifting shaft and the tooth frame; the first feed lifting transmission unit comprises a feed lifting eccentric wheel, a feed lifting connecting rod, a first feed lifting swing plate, a second feed lifting swing plate and a feed lifting crank fixed on a feed lifting shaft, wherein the feed lifting eccentric wheel, the feed lifting connecting rod, the first feed lifting swing plate, the second feed lifting swing plate and the feed lifting crank are fixed on a main shaft, the upper end of the feed lifting connecting rod is rotatably sleeved on the periphery of the feed lifting eccentric wheel, the lower end of the feed lifting connecting rod, one end of the first feed lifting swing plate and one end of the second feed lifting swing plate are coaxially hinged, the other end of the first feed lifting swing plate is hinged with the feed lifting swing seat, and the other end of the second feed lifting swing plate is hinged with the feed lifting crank.

Further, the feed lifting height adjusting unit comprises an adjusting stud in threaded connection with the shell of the lockstitch sewing machine, an adjusting knob fixed at one end of the adjusting stud, an adjusting crank capable of rotating around a sixth fixed swing fulcrum, and an adjusting connecting rod, the other end of the adjusting stud is in contact fit with the adjusting crank, and two ends of the adjusting connecting rod are respectively hinged with the adjusting crank and the feed lifting swing seat.

Furthermore, the lifting tooth height adjusting unit further comprises a tension spring, two ends of the tension spring are hinged to the flat sewing machine shell and the adjusting crank respectively, and the tension spring applies acting force to the adjusting crank, wherein the acting force rotates towards the direction close to the adjusting stud.

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

on one hand, the presser foot lifting and needle adjusting device realizes that the same driving source is adopted to drive the presser foot lifting and the needle adjusting distance, and has compact structure and small occupied volume; on the other hand, the height of the lifting tooth is adjustable, the feeding tooth automatically descends to the position below the upper surface of the needle plate when the presser foot is lifted, discharging is facilitated, and meanwhile the performance of the flat sewing machine is greatly improved.

Drawings

FIG. 1 is a schematic structural diagram of a tooth lifting mechanism in a lockstitch sewing machine in the prior art.

FIG. 2 is a side view of a prior art lockstitch machine during a stop to deposit work material.

FIG. 3 is a schematic structural diagram of a first embodiment of a lockstitch sewing machine of the present application.

Fig. 4 is a schematic view showing the connection between the presser foot lifting transmission unit, the lifting tooth height adjusting unit and the lifting tooth swing seat in fig. 3.

Fig. 5 is a schematic structural diagram of the first tooth lifting transmission unit in fig. 3.

Fig. 6 is an exploded view of fig. 5.

Fig. 7 is a schematic view of the structure of the presser foot lifting cam in fig. 3.

FIG. 8 is a schematic structural diagram of a second embodiment of the lockstitch sewing machine of the present application.

Fig. 9 and 10 are schematic views illustrating connection among the lift pin and foot transmission unit, the lift tooth height adjustment unit and the lift tooth swing seat in fig. 8 at different viewing angles.

Fig. 11 is a schematic structural view of the first tooth lifting transmission unit in fig. 8.

Fig. 12 is a graph showing a change in the movement locus of the feed dog when the feed dog height is adjusted by the feed dog height adjusting unit according to the present application.

Description of the element reference numerals

10. Main shaft

20. Presser foot

30. Lift presser foot mechanism

31. Right lever

32. Pull rod for lifting presser foot

33. Left lever

34. Lift presser foot lifting plate

35. Pressure bar guide frame

36. Pressure lever

41. Swing seat for lifting tooth

411. Seat body part

412. Guide plate

42. Feed lifting rock shaft

43. Feed lifting eccentric wheel

44. Feed lifting connecting rod

45. Transmission slide block

46. Transmission connecting rod

47. Feed lifting crank

48. First lifting swing plate

49. Second lifting swing plate

50. Feeding swing seat

60. Driving source

70. Lift presser foot driving piece

71. Lift presser foot drive section

72. Idle stroke section

80. Needle pitch adjusting driving piece

90. Lift presser foot drive unit

91. Transmission lever

92. Roller wheel

93. Transmission pull rod

94. Fixing support

110. Needle pitch adjustment transmission unit

111. Needle pitch adjusting connecting rod

120. Lower supply pull rod

121. Dodging groove

130. Feed lifting height adjusting unit

131. Adjusting stud

132. Adjusting knob

133. Adjusting crank

134. Adjusting connecting rod

135. Tension 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 flat seamer, as shown in FIG. 8, having a main shaft 10 driven to rotate by a main motor. For convenience of description, the following embodiments define the directions as follows: defining the axial direction of a main shaft 10 in the sewing machine as a left-right direction, wherein the direction of the main shaft 10 towards the head (namely the needle side) of the sewing machine is a left direction, and the direction of the main shaft 10 towards the tail of the sewing machine is a right direction; defining the moving direction of the sewing material when the sewing machine is used for sewing as a front direction; a direction orthogonal to both the front-rear direction and the left-right direction is defined as an up-down direction.

As shown in fig. 3 or 8, the flat sewing machine includes a rack, feed teeth fixed on the rack, a feed lifting tooth mechanism connected between the main shaft 10 and the rear end of the rack, a feed mechanism connected between the main shaft 10 and the front end of the rack, a presser foot 20, a presser foot lifting mechanism 30 connected to the presser foot 20, a driving source 60, a presser foot lifting driving member 70 and a needle pitch adjusting driving member 80 both driven by the driving source 60 to rotate, a presser foot lifting transmission unit 90 connected between the presser foot lifting driving member 70 and the presser foot lifting mechanism 30, a needle pitch adjusting transmission unit 110 connected between the needle pitch adjusting driving member 80 and the feed swing seat 50, a lower feed pull rod 120, and a lifter height adjusting unit 130 in addition to the main shaft 10 extending left and right. The feed lifting mechanism is provided with a feed lifting swing seat 41 capable of rotating around a first fixed swing fulcrum O1, and the angle of the feed lifting swing seat 41 determines the feed lifting height of the lockstitch sewing machine; the feeding mechanism is provided with a feeding swing seat 50 which can rotate around a second fixed swing fulcrum O2, and the angle of the feeding swing seat 50 determines the needle pitch of the flat sewing machine; the upper end of the lower supply pull rod 120 is hinged with a transmission part in the pressure raising and pressing foot transmission unit 90 through a pin extending from left to right, and the lower end of the lower supply pull rod 120 is hinged with the left end surface of the tooth raising swing seat 41 through a pin extending from left to right; the lift tab height adjusting unit 130 acts on the lift tab swinging seat 41 to change the angle of the lift tab swinging seat 41.

Further, as shown in fig. 3 and 8, the driving source 60 is a motor, and the presser foot lifting driving member 70 and the needle pitch adjusting driving member 80 are fixed to a motor shaft of the driving source 60. In the range that the motor shaft of the driving source 60 rotates for 360 degrees for one circle, the rotation angle of the motor shaft of the driving source 60 at least has a pressure foot lifting working area and a needle pitch adjusting working area, and the pressure foot lifting working area and the needle pitch adjusting working area are two mutually independent rotation angle ranges.

When the flat sewing machine sews normally, the rotation angle of the motor shaft of the driving source 60 is a certain rotation angle value in the needle pitch adjusting working area, the driving source 60 keeps the feeding swing seat 50 at an angle through the needle pitch adjusting driving piece 80 and the needle pitch adjusting transmission unit 110, and further the flat sewing machine keeps the current needle pitch; the feed lifting tooth height adjusting unit 130 keeps the feed lifting tooth swinging seat 41 at an angle, so that the flat sewing machine keeps the current feed lifting tooth height; the main motor drives the main shaft 10 to rotate, the main shaft 10 drives the tooth rack and the feeding teeth fixed on the tooth rack to do reciprocating motion back and forth in the horizontal direction through the feeding mechanism, the main shaft 10 drives the tooth rack and the feeding teeth fixed on the tooth rack to do reciprocating motion up and down in the vertical direction through the tooth lifting mechanism, and then the feeding teeth do composite motion of the reciprocating motion back and forth and the reciprocating motion up and down to execute feeding action.

When the sewing machine automatically lifts the presser foot, the motor shaft of the driving source 60 rotates to a certain rotation angle value in the presser foot lifting working area from the current rotation angle, the driving source 60 drives the presser foot lifting driving piece 70 and the needle pitch adjusting driving piece 80 to rotate, and when the motor shaft of the driving source 60 operates in the presser foot lifting working area, power transmission exists between the presser foot lifting driving piece 70 and the presser foot lifting transmission unit 90; therefore, the presser foot lifting driving component 70 drives the presser foot lifting transmission unit 90 to act, the presser foot lifting transmission unit 90 drives the presser foot lifting mechanism 30 to act to lift the presser foot 20 upwards, and meanwhile, the transmission component in the presser foot lifting transmission unit 90 drives the tooth lifting swing seat 41 to rotate around the second fixed swing fulcrum O2 through the lower supply pull rod 120, so that the feeding tooth automatically descends to the position below the upper surface of the needle plate in the flat sewing machine, namely the feeding tooth is flush with the upper surface of the needle plate or lower than the upper surface of the needle plate. Therefore, when the presser foot 20 is lifted upwards, the feeding teeth can not be protruded upwards from the needle plate all the time, the sewing material can be taken away from the lower part of the presser foot 20 or put into the lower part of the presser foot 20 conveniently, the sewing material can be taken and put in the lower part, and a series of bad phenomena caused by the fact that the feeding teeth scrape the sewing material can be avoided.

When the stitch length of the flat sewing machine is adjusted, a motor shaft of the driving source 60 rotates from a certain rotation angle value in a stitch length adjusting working area to another rotation angle value in the stitch length adjusting working area, then the driving source 60 drives the pressure lifting pin driving piece 70 and the stitch length adjusting driving piece 80 to rotate, the stitch length adjusting driving piece 80 drives the feeding swing seat 50 to rotate around the first fixed swing fulcrum O1 through the stitch length adjusting transmission unit 110, the angle of the feeding swing seat 50 is changed, the stitch length of the flat sewing machine is changed, and stitch length adjustment is achieved; however, since no power is transmitted between the presser foot lifting drive member 70 and the presser foot lifting transmission unit 90, even if the presser foot lifting drive member 70 rotates, the presser foot lifting transmission unit 90 does not operate, and the presser foot lifting mechanism 30 and the lower feed link 120 do not operate, thereby avoiding interference between the state of the presser foot 20 and the state of the tooth lifting swing seat 41 at the time of adjusting the needle pitch.

When the height of the lifting tooth of the lockstitch sewing machine is adjusted, the lifting tooth height adjusting unit 130 acts on the lifting tooth swinging seat 41 to change the angle of the lifting tooth swinging seat 41, so that the height of the lifting tooth of the lockstitch sewing machine is changed, and the height adjustment of the lifting tooth is realized. In addition, when the height of the feed lifting teeth of the flat sewing machine is adjusted, only the angle of the feed lifting teeth swinging seat 41 is changed, but the angle of the feed swinging seat 50 is not changed under the action of the driving source 60, so that the motion track of the feed lifting teeth is changed in an equal ratio only in the vertical direction relative to the upper surface of the needle plate, as shown in fig. 12. Specifically, in the motion trajectory diagram of the feed dog shown in fig. 12, the Z direction indicates the tooth lifting height of the feed dog, the X direction indicates the needle pitch, and L indicates the upper surface of the needle plate; when the swing amplitude of the feeding tooth in the up-and-down direction is reduced by changing the angle of the lifting tooth swing seat 41, the motion track of the feeding tooth is changed from a curve S1 in a graph 12 to a curve S3, the height of the lifting tooth of the feeding tooth is reduced, and the sewing machine is in a low-tooth mode, is suitable for sewing thin materials and can improve the wrinkling phenomenon of the sewing materials. When the swing amplitude of the feeding teeth in the up-and-down direction is increased by changing the angle of the feeding teeth swinging seat 41, the motion track of the feeding teeth is changed from a curve S1 in fig. 12 to a curve S2, the height of the feeding teeth is increased, and the sewing machine is in a high teeth mode, so that the feeding efficiency can be effectively improved, and the feeding is smoother. As can be seen from fig. 12: when the feed lifting tooth height of the feed lifting tooth is adjusted, the motion track of the feed lifting tooth does not move up or down integrally, but only changes the amplitude in the up-down direction, but does not change the amplitude in the front-back direction, namely the needle pitch of the sewing machine is kept unchanged in the process of adjusting the feed lifting tooth height, so that the sewing quality is not influenced.

From the above, it can be seen that: on one hand, the presser foot lifting and needle adjusting device realizes that the same driving source 60 is adopted to drive the presser foot lifting and needle adjusting, and has compact structure and small occupied volume; on the other hand, the height of the lifting tooth is adjustable, the feeding tooth automatically descends to the position below the upper surface of the needle plate when the presser foot is lifted, the material is convenient to discharge, and meanwhile, the performance of the flat sewing machine is greatly improved. In addition, the driving source 60 adopts a motor, when the presser foot is lifted, the motor shaft of the driving source 60 has a plurality of outputs, or the motor shaft of the driving source 60 can operate and maintain any rotation angle value in the presser foot lifting working area, thereby the presser foot 20 can be lifted upwards to different heights, and the height of the presser foot is controllable.

Further, in the flat bed sewing machine related to the present application, the structure of the feeding mechanism is the prior art, and reference may be made to a sewing machine disclosed in the chinese patent application No. 201910098281.1, so that the description thereof is not repeated here. As shown in fig. 3 or fig. 8, the feed lifting mechanism in the flat sewing machine includes a feed lifting shaft 42 parallel to the main shaft 10, a first feed lifting transmission unit connected between the main shaft 10 and the feed lifting shaft 42, and a second feed lifting transmission unit connected between the feed lifting shaft 42 and the feed lifting frame, and the structure of the second feed lifting transmission unit is also the prior art, and can be referred to a sewing machine disclosed in the chinese patent application No. 201910098281.1, and therefore the description thereof is omitted here; however, the first feed dog transmission unit has two preferred embodiments in the present application, so that the lockstitch sewing machine has two preferred embodiments. The following description will proceed with two preferred embodiments of the lockstitch machine.

As shown in fig. 3, 5 and 6, a first lifting tooth transmission unit in the first flat seamer embodiment comprises a lifting tooth eccentric wheel 43 fixed on the main shaft 10, a lifting tooth connecting rod 44, a sliding chute arranged in the lifting tooth swinging seat 41, a transmission slide block 45 in sliding fit with the sliding chute, a transmission connecting rod 46 and a lifting tooth crank 47 fixed on the lifting tooth shaft 42, wherein the upper end of the lifting tooth connecting rod 44 is rotatably sleeved on the periphery of the lifting tooth eccentric wheel 43, the lower end of the lifting tooth connecting rod 44, the transmission slide block 45 and one end of the transmission connecting rod 46 are coaxially hinged through a pin extending from left to right, and the other end of the transmission connecting rod 46 is hinged with the lifting tooth crank 47 through a pin extending from left to right. The main shaft 10 drives the feed lifting eccentric wheel 43 to rotate, the feed lifting eccentric wheel 43 drives the feed lifting crank 47 to swing through the feed lifting connecting rod 44, the transmission slide block 45, the transmission connecting rod 46 and the feed lifting swing seat 41, and further drives the feed lifting shaft 42 to swing, and the angle of the feed lifting swing seat 41 determines the swing amplitude of the main shaft 10 driving the feed lifting shaft 42 to swing through the first feed lifting transmission unit; when the swing amplitude of the feed lifting tooth shaft 42 becomes smaller, the feed lifting tooth height of the feed lifting tooth is reduced; when the swing amplitude of the feed lifting tooth shaft 42 is increased, the feed lifting tooth height of the feed lifting tooth is increased. The first feed lifting transmission unit in the first embodiment of the lockstitch sewing machine is a compound crank slider mechanism.

Preferably, as shown in fig. 5 and 6, there are two sets of sliding grooves and transmission sliding blocks 45 which are in sliding fit and are distributed on the left and right sides of the tooth lifting link 44 in the axial direction of the tooth lifting shaft 42, a connection groove is further opened in the lower end of the tooth lifting link 44, and the end of the transmission link 46 is located in the connection groove in the lower end of the tooth lifting link 44. The structure is a bilateral symmetry structure, so that the whole stress stability of the first tooth lifting transmission unit can be ensured, and the risk of unilateral stress is reduced. Further, the tooth raising swing seat 41 is composed of two parts: the lifting tooth swing seat 41 includes a seat body portion 411 and two guide plates 412, the seat body portion 411 is provided with a step portion at both sliding grooves, the two guide plates 412 are fixed at the step portion of the seat body portion 411 by screws, the sliding grooves are formed between the guide plates 412 and the step portion, and the lower end of the lifting tooth link 44 is received in a groove formed between the two step portions of the seat body portion 411. Both the left and right sides of the seat body portion 411 are rotatably mounted to fixing pins extending left and right, the fixing pins being fixed in the sewing machine cabinet, the seat body portion 411 being rotatable about the fixing pins, the fixing pins constituting the first fixed swing fulcrum O1 of the feed dog swing seat 41.

Second embodiment of the lockstitch sewing machine, as shown in fig. 8 and 11, the first lift tooth transmission unit in the second embodiment of the lockstitch sewing machine includes a lift tooth eccentric wheel 43 fixed on the main shaft 10, a lift tooth connecting rod 44, a first lift tooth swinging plate 48, a second lift tooth swinging plate 49, and a lift tooth crank 47 fixed on the lift tooth shaft 42, the upper end of the lift tooth connecting rod 44 is rotatably fitted around the periphery of the lift tooth eccentric wheel 43, the lower end of the lift tooth connecting rod 44, one end of the first lift tooth swinging plate 48, and one end of the second lift tooth swinging plate 49 are coaxially hinged by pins extending from left to right, the other end of the first lift tooth swinging plate 48 is hinged with the lift tooth swinging seat 41 by pins extending from left to right, and the other end of the second lift tooth swinging plate 49 is hinged with the lift tooth crank 47 by pins extending from left to right. The main shaft 10 drives the feed lifting eccentric wheel 43 to rotate, the feed lifting eccentric wheel 43 drives the feed lifting crank 47 to swing through the feed lifting connecting rod 44, the first feed lifting swing plate 48, the second feed lifting swing plate 49 and the feed lifting swing seat 41, and further drives the feed lifting shaft 42 to swing, and the angle of the feed lifting swing seat 41 determines the swing amplitude of the main shaft 10 driving the feed lifting shaft 42 to swing through the first feed lifting transmission unit; when the swing amplitude of the feed lifting tooth shaft 42 becomes smaller, the feed lifting tooth height of the feed lifting tooth is reduced; when the swing amplitude of the feed lifting tooth shaft 42 is increased, the feed lifting tooth height of the feed lifting tooth is increased. The first feed dog transmission unit in the first embodiment of the lockstitch sewing machine is a compound multi-link mechanism.

Preferably, as shown in fig. 11, the lift tab swing seat 41 has a concave structure, the left and right sides of the lift tab swing seat 41 are rotatably mounted to fixing pins extending left and right, the fixing pins are fixed in the case of the lockstitch sewing machine, the lift tab swing seat 41 is rotatable around the fixing pins, and the fixing pins constitute a first fixed swing fulcrum O1 of the lift tab swing seat 41.

Further, in the two embodiments of the sewing machine, as shown in fig. 3 or fig. 8, the needle pitch adjusting driving member 80 is a needle pitch adjusting eccentric wheel, the needle pitch adjusting transmission unit 110 includes a needle pitch adjusting connecting rod 111, an upper end of the needle pitch adjusting connecting rod 111 is rotatably sleeved on an outer circumference of the needle pitch adjusting eccentric wheel, and a lower end of the needle pitch adjusting connecting rod 111 is hinged to the feeding swing seat 50 through a pin extending from left to right.

Further, the preferred structure of the presser foot lifting mechanism 30 is: as shown in fig. 3 or 8, the presser foot lifting mechanism 30 includes a right lever 31 rotatable about a fourth fixed swing fulcrum O4, a presser foot lifting pull rod 32, a left lever 33 rotatable about a fifth fixed swing fulcrum O5, a presser foot lifting plate 34, a presser foot guide 35, and a presser bar 36 extending vertically, a left end of the right lever 31 is hinged to a right end of the presser foot lifting pull rod 32, a left end of the presser foot lifting pull rod 32 is hinged to one end of the left lever 33, the other end of the left lever 33 is hinged to an upper end of the presser foot lifting plate 34, a lifting hook portion is provided on the presser foot lifting plate 34, a connecting protrusion portion engaged with the lifting hook portion is provided on the presser foot guide 35, the presser foot guide 35 is fixed to an upper end of the presser bar 36, and the presser foot 20 is mounted to a lower end of the presser bar 36. When the presser foot is lifted, taking the view angle shown in fig. 3 as an example, the right lever 31 is driven by the driving source 60 to rotate clockwise around the fourth fixed swing fulcrum O4 through the presser foot lifting driving member 70 and the presser foot lifting transmission unit 90, the presser foot lifting pull rod 32 is pulled rightwards by the right lever 31, the left lever 33 rotates anticlockwise around the fifth fixed swing fulcrum O5, the press rod 36 is driven by the left lever 33 to move upwards through the presser foot lifting plate 34 and the press rod guide 35, and the press rod 20 is driven by the press rod 36 to move upwards together, so that the presser foot is lifted.

Further, as shown in fig. 4 and 7 or 9, the lifting and pressing foot driving member 70 is a lifting and pressing foot cam, and the outer peripheral surface of the lifting and pressing foot cam is provided with a lifting and pressing foot driving section 71 which is a diameter-variable surface and an idle stroke section 72 which is an equal-diameter surface; the presser foot lifting transmission unit 90 comprises a transmission lever 91 capable of rotating around a third fixed swing fulcrum O3, a roller 92 rotatably mounted at the rear end of the transmission lever 91, and a transmission pull rod 93, wherein the lower end of the transmission pull rod 93 is hinged with the front end of the transmission lever 91 through a pin extending left and right, the upper end of the transmission pull rod 93 is hinged with the right end of the right lever 31 through a pin extending front and back, and the upper end of the lower supply pull rod 120 is hinged with the transmission lever 91. When the presser foot is automatically lifted, the motor shaft of the driving source 60 rotates to a rotation angle value in the presser foot lifting working area from the current rotation angle value, when the motor shaft of the driving source 60 operates in the presser foot lifting working area, the roller 92 is in contact fit with the presser foot lifting driving section 71 of the presser foot lifting cam, at the moment, the presser foot lifting driving section 71 on the presser foot lifting cam drives the transmission lever 91 to rotate around the third fixed swing fulcrum O3 through the roller 92, on one hand, the presser foot lifting mechanism 30 is driven to act and lift the presser foot, on the other hand, the lower supply pull rod 120 is used for driving the tooth lifting swing seat 41 to rotate, and the feeding tooth is automatically lowered below the upper surface of the needle plate to perform the downward supply action. When the needle pitch is adjusted, a motor shaft of the driving source 60 operates in a needle pitch adjusting working area, at the moment, the roller 92 is in contact fit with the idle stroke section 72 of the presser foot lifting cam, the transmission lever 91 does not rotate, the presser foot lifting mechanism 30 and the lower supply pull rod 120 do not operate, and the flat sewing machine keeps the current presser foot height and the current tooth lifting height.

Preferably, as shown in fig. 4 or fig. 8, the lower supply rod 120 is hinged to the transmission lever 91 through an axial screw parallel to the main shaft 10, an avoidance groove 121 extending along the length direction of the lower supply rod 120 is formed on the lower supply rod 120, and the axial screw is inserted into the avoidance groove 121 of the lower supply rod 120; when the lifting tooth height adjusting unit 130 changes the angle of the lifting tooth swing seat 41, the escape groove 121 moves relative to the axial screw. Therefore, when the lift pin height is adjusted, the angle of the lift pin swing base 41 is changed, but due to the existence of the escape groove 121, the rotation of the lift pin swing base 41 is prevented from being transmitted to the transmission lever through the lower supply link 120, thereby preventing interference with the presser foot lifting mechanism 30. In addition, as shown in fig. 4, the presser foot lifting transmission unit 90 further includes a fixing bracket 94 fixed to the body of the flat bed sewing machine, the transmission lever 91 is rotatably mounted to a support shaft extending in the left and right direction and fixed in the fixing bracket 94, and the support shaft constitutes a third fixed swing fulcrum O3 of the transmission lever 91; the hinge point between the transmission lever 91 and the lower supply pull rod 120 is located between the front end of the transmission lever 91 and the third fixed swing fulcrum O3 of the transmission lever 91.

Further, the preferred structure of the lifting tooth height adjusting unit 130 is: as shown in fig. 4 or 9, the feed lifting height adjusting unit 130 includes an adjusting stud 131 screwed into the flat bed sewing machine casing and extending forward and backward, an adjusting knob 132 fixed to the rear end of the adjusting stud 131, an adjusting crank 133 capable of rotating around a sixth fixed swing fulcrum O6, and an adjusting link 134, wherein the front end of the adjusting stud 131 is in contact fit with the adjusting crank 133, and the upper and lower ends of the adjusting link 134 are hinged to the adjusting crank 133 and the feed lifting swing seat 41 through pins extending leftward and rightward, respectively. The adjusting knob 132 is rotated, the adjusting knob 132 drives the adjusting stud 131 to rotate together, the adjusting stud 131 is driven to move forwards or backwards, the adjusting crank 133 is driven to rotate around the sixth fixed swing fulcrum O6, the lifting tooth swing seat 41 is driven to rotate through the adjusting connecting rod 134, the angle of the lifting tooth swing seat 41 is changed, and the lifting tooth height of the feeding tooth is adjusted. Preferably, the feed lifting height adjusting unit 130 further comprises a tension spring 135, two ends of the tension spring 135 are respectively hinged with the lockstitch sewing machine casing and the adjusting crank 133, and the tension spring 135 applies an acting force to the adjusting crank 133 to rotate towards the direction close to the adjusting stud 131, so as to ensure that the adjusting stud 131 and the adjusting crank 133 are always reliably contacted and matched.

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 (11)

1. A flush joint machine comprises a main shaft (10), a tooth rack, feeding teeth fixed on the tooth rack, a tooth lifting mechanism connected between the main shaft (10) and one end of the tooth rack, a feeding mechanism connected between the main shaft (10) and the other end of the tooth rack, a presser foot (20) and a presser foot lifting mechanism (30) connected with the presser foot (20); the feed lifting mechanism is provided with a feed lifting swing seat (41) capable of rotating around a first fixed swing fulcrum (O1), and the angle of the feed lifting swing seat (41) determines the feed lifting height of the lockstitch sewing machine; the feeding mechanism is provided with a feeding swing seat (50) capable of rotating around a second fixed swing fulcrum (O2), and the angle of the feeding swing seat (50) determines the needle pitch of the flat sewing machine; the method is characterized in that: the device is characterized by further comprising a driving source (60), a presser foot lifting driving piece (70) and a needle distance adjusting driving piece (80) which are driven by the driving source (60) to rotate, a presser foot lifting transmission unit (90) connected between the presser foot lifting driving piece (70) and a presser foot lifting mechanism (30), a needle distance adjusting transmission unit (110) connected between the needle distance adjusting driving piece (80) and a feeding swing seat (50), a lower feed pull rod (120) and a tooth lifting height adjusting unit (130), wherein two ends of the lower feed pull rod (120) are respectively hinged with a transmission part in the presser foot lifting transmission unit (90) and the tooth lifting swing seat (41), and the tooth lifting height adjusting unit (130) acts on the tooth lifting swing seat (41) and is used for changing the angle of the tooth lifting swing seat (41);

when the presser foot is automatically lifted, the driving source (60) drives the presser foot lifting driving piece (70) and the needle pitch adjusting driving piece (80) to rotate, power is transmitted between the presser foot lifting driving piece (70) and the presser foot lifting transmission unit (90), the presser foot lifting driving piece (70) drives the presser foot lifting mechanism (30) to act through the presser foot lifting transmission unit (90) so that the presser foot (20) is lifted upwards, and meanwhile, a transmission part in the presser foot lifting transmission unit (90) drives the tooth lifting swing seat (41) to rotate around a second fixed swing fulcrum (O2) through the lower supply pull rod (120) so that the feeding tooth automatically descends below the upper surface of a needle plate in the lockstitch sewing machine;

when the needle pitch is adjusted, the driving source (60) drives the pressure foot lifting driving piece (70) and the needle pitch adjusting driving piece (80) to rotate, no power is transmitted between the pressure foot lifting driving piece (70) and the pressure foot lifting transmission unit (90), and the needle pitch adjusting driving piece (80) drives the feeding swing seat (50) to rotate around the first fixed swing fulcrum (O1) through the needle pitch adjusting transmission unit (110) to change the needle pitch of the flat sewing machine.

2. The lockstitch machine of claim 1, wherein: the driving source (60) is a motor, and the pressure lifting and pressing foot driving part (70) and the needle distance adjusting driving part (80) are both fixed on a motor shaft of the driving source (60).

3. The lockstitch machine according to claim 1 or 2, characterized in that: the needle pitch adjusting driving piece (80) is an eccentric wheel for adjusting the needle pitch, the needle pitch adjusting transmission unit (110) comprises a needle pitch adjusting connecting rod (111), one end of the needle pitch adjusting connecting rod (111) is rotatably sleeved on the periphery of the eccentric wheel for adjusting the needle pitch, and the other end of the needle pitch adjusting connecting rod (111) is hinged with the feeding swing seat (50).

4. The lockstitch machine according to claim 1 or 2, characterized in that: the presser foot lifting driving part (70) is a presser foot lifting cam, and the outer peripheral surface of the presser foot lifting cam is provided with a presser foot lifting driving section (71) which is a diameter-variable surface and an idle stroke section (72) which is an equal-diameter surface; the presser foot lifting transmission unit (90) comprises a transmission lever (91) capable of rotating around a third fixed swing fulcrum (O3), a roller (92) rotatably mounted at one end of the transmission lever (91), and a transmission pull rod (93), wherein two ends of the transmission pull rod (93) are respectively hinged with the other end of the transmission lever (91) and a right lever (31) in the presser foot lifting mechanism (30), and the lower supply pull rod (120) is hinged with the transmission lever (91); when the presser foot is automatically lifted, the roller (92) is in contact fit with a presser foot lifting driving section (71) of the presser foot lifting cam; when the needle pitch is adjusted, the roller (92) is in contact fit with the idle stroke section (72) of the pressure foot lifting cam.

5. The lockstitch machine of claim 4, wherein: the presser foot lifting mechanism (30) comprises a right lever (31) capable of rotating around a fourth fixed swing fulcrum (O4), a presser foot lifting pull rod (32), a left lever (33) capable of rotating around a fifth fixed swing fulcrum (O5), a presser foot lifting plate (34), a presser foot guide frame (35) and a presser bar (36) extending up and down, wherein the right lever (31) is hinged to one end of the presser foot lifting pull rod (32), the other end of the presser foot lifting pull rod (32) is hinged to one end of the left lever (33), the other end of the left lever (33) is hinged to the upper end of the presser foot lifting plate (34), a lifting hook part is arranged on the presser foot lifting plate (34), a connecting protruding part clamped with the lifting hook part is arranged on the presser bar guide frame (35), the presser bar guide frame (35) is fixed to the upper end of the presser bar (36), and the presser foot (20) is installed at the lower end of the presser bar (36).

6. The lockstitch machine of claim 4, wherein: the lower supply pull rod (120) is hinged with the transmission lever (91) through a shaft position screw parallel to the main shaft (10), an avoiding groove (121) extending along the length direction of the lower supply pull rod (120) is formed in the lower supply pull rod (120), and the shaft position screw penetrates through the avoiding groove (121) of the lower supply pull rod (120); when the lifting tooth height adjusting unit (130) changes the angle of the lifting tooth swinging seat (41), the avoiding groove (121) moves relative to the axial screw.

7. The lockstitch machine of claim 1, wherein: the tooth lifting mechanism further comprises a tooth lifting shaft (42) parallel to the main shaft (10), a first tooth lifting transmission unit connected between the main shaft (10) and the tooth lifting shaft (42), and a second tooth lifting transmission unit connected between the tooth lifting shaft (42) and the tooth frame; the first tooth lifting transmission unit comprises a tooth lifting eccentric wheel (43) fixed on a main shaft (10), a tooth lifting connecting rod (44), a sliding groove arranged in a tooth lifting swing seat (41), a transmission sliding block (45) in sliding fit with the sliding groove, a transmission connecting rod (46) and a tooth lifting crank (47) fixed on a tooth lifting shaft (42), wherein the upper end of the tooth lifting connecting rod (44) is rotatably sleeved on the periphery of the tooth lifting eccentric wheel (43), the lower end of the tooth lifting connecting rod (44), the transmission sliding block (45) and one end of the transmission connecting rod (46) are coaxially hinged, and the other end of the transmission connecting rod (46) is hinged with the tooth lifting crank (47).

8. The lockstitch machine of claim 7, wherein: two groups of sliding grooves and transmission sliding blocks (45) which are in sliding fit are arranged, the sliding grooves and the transmission sliding blocks are distributed on two sides of the tooth lifting connecting rod (44) in the axial direction of the tooth lifting shaft (42), a connecting groove is further formed in the lower end of the tooth lifting connecting rod (44), and the end portion of the transmission connecting rod (46) is located in the connecting groove in the lower end of the tooth lifting connecting rod (44).

9. The lockstitch machine of claim 1, wherein: the tooth lifting mechanism further comprises a tooth lifting shaft (42) parallel to the main shaft (10), a first tooth lifting transmission unit connected between the main shaft (10) and the tooth lifting shaft (42), and a second tooth lifting transmission unit connected between the tooth lifting shaft (42) and the tooth frame; the first lifting tooth transmission unit comprises a lifting tooth eccentric wheel (43), a lifting tooth connecting rod (44), a first lifting tooth swinging plate (48), a second lifting tooth swinging plate (49) and a lifting tooth crank (47) fixed on a lifting tooth shaft (42), wherein the lifting tooth eccentric wheel (43) is fixed on a main shaft (10), the upper end of the lifting tooth connecting rod (44) is rotatably sleeved on the periphery of the lifting tooth eccentric wheel (43), the lower end of the lifting tooth connecting rod (44), one end of the first lifting tooth swinging plate (48) and one end of the second lifting tooth swinging plate (49) are coaxially hinged, the other end of the first lifting tooth swinging plate (48) is hinged with the lifting tooth swinging seat (41), and the other end of the second lifting tooth swinging plate (49) is hinged with the lifting tooth crank (47).

10. The lockstitch machine of claim 1, wherein: the feed lifting tooth height adjusting unit (130) comprises an adjusting stud (131) in threaded connection with a flat sewing machine shell, an adjusting knob (132) fixed at one end of the adjusting stud (131), an adjusting crank (133) capable of rotating around a sixth fixed swing fulcrum (O6) and an adjusting connecting rod (134), the other end of the adjusting stud (131) is in contact fit with the adjusting crank (133), and two ends of the adjusting connecting rod (134) are hinged to the adjusting crank (133) and the feed lifting tooth swing seat (41) respectively.

11. The lockstitch machine of claim 10, wherein: the lifting tooth height adjusting unit (130) further comprises a tension spring (135), two ends of the tension spring (135) are hinged to the sewing machine shell and the adjusting crank (133) respectively, and the tension spring (135) applies acting force to the adjusting crank (133) to rotate towards the direction close to the adjusting stud (131).

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