CN112626733B - Feed lifting height adjusting method for sewing machine - Google Patents

Abstract

The invention provides a feed lifting tooth height adjusting method for a sewing machine, the sewing machine is provided with a main shaft, a feed lifting tooth shaft parallel to the main shaft, a feed lifting tooth arranged on the feed lifting tooth frame, a first feed lifting tooth transmission assembly connected between the main shaft and the feed lifting tooth shaft, and a second feed lifting tooth transmission assembly connected between the feed lifting tooth shaft and the feed lifting tooth frame, and the feed lifting tooth height adjusting method comprises the following steps: 1) The sewing machine is provided with a feed lifting tooth height adjusting mechanism, and the feed lifting tooth height adjusting mechanism acts on the first feed lifting tooth transmission assembly; 2) When the height of the lifting teeth needs to be adjusted, the lifting tooth height adjusting mechanism acts to change the transmission efficiency of the first lifting tooth transmission assembly, so that the swing amplitude of the main shaft driving the lifting tooth shaft to swing through the first lifting tooth transmission assembly is changed, the height of the feeding lifting teeth is adjusted, the universality of the sewing machine is greatly improved, the adaptability of the sewing machine to different sewing materials is greatly enhanced, and the competitiveness of the product is improved.

Description

Feed lifting height adjusting method for sewing machine

Technical Field

The invention relates to the field of sewing machines, in particular to a feed lifting tooth height adjusting method for a sewing machine.

Background

As shown in fig. 1, various sewing machines (i.e., flat sewing machines) on the market at present include a main shaft 100 driven by a main motor to rotate, a thread frame 200, a feed dog 300 installed on the thread frame 200, a feed dog mechanism 400 connected between the main shaft 100 and one end of the thread frame 200, and a feed mechanism 500 connected between the main shaft 100 and the other end of the thread frame 200, wherein the main shaft 100 drives the thread frame 200 and the feed dog 300 to reciprocate up and down through the thread dog mechanism 400, and the main shaft 100 drives the thread frame 200 and the feed dog 300 to reciprocate back and forth through the feed mechanism 500. Therefore, the feeding tooth 300 performs a compound motion of up-and-down reciprocating motion and back-and-forth reciprocating motion, and the motion track thereof is similar to an ellipse, as shown in fig. 2. Further, as shown in fig. 1, the feed lifting mechanism 400 includes a feed lifting shaft 401 parallel to the main shaft 100, a feed lifting eccentric 402 fixed to the main shaft 100, a feed lifting connecting rod 403, and a feed lifting crank 404 and a feed lifting fork 405 fixed to both ends of the feed lifting shaft 401 by screws, wherein the feed lifting connecting rod 403 is connected to the feed lifting eccentric 402 and the feed lifting crank 404 at upper and lower ends thereof, and the feed lifting fork 405 is connected to the feed lifting frame 200 by a slider.

In the existing sewing machine shown in fig. 1, the transmission ratio of the main shaft 100 to the tooth frame 200 in the whole transmission process is fixed, so that the tooth lifting height of the feed tooth 300 (i.e. the distance from the upper surface of the needle plate when the feed tooth moves to the highest point) in the sewing machine is a fixed value, i.e. the highest point value in the running process of the feed tooth 300 is fixed, and is set according to the machine type assembly process, and the tooth lifting height of the feed tooth 300 set by the method is generally the standard height. However, in order to adapt to different sewing material thicknesses, the feed lifting tooth height is often required to be adjusted, and the current method for adjusting the feed lifting tooth height is as follows: the screws for fixing the lifting tooth fork 405 and the lifting tooth shaft 401 in the figure 1 are loosened manually, the mounting position of the lifting tooth fork 405 relative to the lifting tooth shaft 401 is adjusted by using a special measuring tool, and after the adjustment is finished, the screws are screwed down, so that the lifting tooth fork 405 is locked and fixed on the lifting tooth shaft 401, and different lifting tooth heights are obtained. The adjusting process of the height of the feed dog is quite complex, needs professional machine maintenance personnel to operate, and is not suitable for general sewing workers to operate, so that the labor intensity of the sewing workers is obviously improved, and the sewing experience is greatly reduced.

Particularly, after the height of the feed lifting teeth is adjusted in the above manner, the swing amplitude of the feed lifting teeth shaft is not changed, but only the mounting position of the feed lifting teeth fork on the feed lifting teeth shaft is changed, so that the movement track of the feed lifting teeth is inevitably moved up or down integrally, and the feed needle pitch of the sewing machine is changed simultaneously when the height of the feed lifting teeth is adjusted. The specific analysis is as follows: the motion trail of the feeding teeth integrally moves up or down, and the change of the motion trail of the feeding teeth is shown in figure 3; as can be seen from fig. 3: when the motion track of the feeding tooth integrally moves downwards and the tooth lifting height of the feeding tooth is reduced from the standard height Z1 (1.0 mm) to Z2 (0.8 mm), the motion track of the feeding tooth is changed from a graph 3b to a graph 3a, and at the moment, the feeding needle pitch of the sewing machine is reduced from the standard needle pitch X1 to X2; when the motion track of the feeding tooth moves upwards integrally and the tooth lifting height of the feeding tooth is increased from the standard height Z1 (1.0 mm) to Z3 (1.2 mm), the motion track of the feeding tooth is changed from a graph 3b to a graph 3c, and at the moment, the feeding needle pitch of the sewing machine is increased from the standard needle pitch X1 to X3. Thus, it can be seen that: in the prior art, the height of the feed lifting tooth is adjusted by changing the mounting position of the feed lifting tooth fork on the feed lifting tooth shaft, but the feed needle pitch of the sewing machine is changed, so that the sewing quality is influenced.

Particularly, the above-mentioned adjustment method of the feed lifting teeth height cannot increase the feed lifting teeth height without limitation, and after the feed lifting teeth height is adjusted to a certain height, if the feed lifting teeth height is continuously increased, for example, to the feed lifting teeth height Z in the view shown in fig. 4, at this time, the needle pitch of the sewing machine is X, when the feed lifting teeth move to the regions P1 and P2 in fig. 4, a phenomenon that the feed lifting teeth pull the sewing material backward and reversely occurs, which affects the sewing quality, and also limits the maximum value of the feed lifting teeth height of the feed lifting teeth.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a feed dog height adjusting method for a sewing machine, which can adjust the feed dog height within a certain range.

In order to achieve the above object, the present invention provides a feed lifting tooth height adjusting method for a sewing machine having a main shaft, a feed lifting tooth shaft parallel to the main shaft, a feed lifting tooth frame, a feed lifting tooth mounted on the feed lifting tooth frame, a first feed lifting tooth transmission assembly connected between the main shaft and the feed lifting tooth shaft, and a second feed lifting tooth transmission assembly connected between the feed lifting tooth shaft and the feed lifting tooth frame, the feed lifting tooth height adjusting method comprising the steps of:

1) The sewing machine is provided with a feed lifting tooth height adjusting mechanism, and the feed lifting tooth height adjusting mechanism acts on a first feed lifting tooth transmission assembly;

2) And when the height of the lifting tooth needs to be adjusted, the lifting tooth height adjusting mechanism acts to change the transmission efficiency of the first lifting tooth transmission assembly, so that the swing amplitude of the main shaft which drives the lifting tooth shaft to swing through the first lifting tooth transmission assembly is changed.

Furthermore, the first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel, a lifting tooth connecting rod and a lifting tooth crank fixed on a lifting tooth shaft, the lifting tooth eccentric wheel is connected with the main shaft, and two ends of the lifting tooth connecting rod are respectively connected with the lifting tooth eccentric wheel and the lifting tooth crank.

Furthermore, the feed lifting tooth height adjusting mechanism changes the feed lifting tooth eccentric amount between the matching center of the feed lifting tooth eccentric wheel and the feed lifting tooth connecting rod and the rotation center of the main shaft.

Further, the feed lifting teeth height adjusting mechanism changes the transmission efficiency between the feed lifting teeth connecting rod and the feed lifting teeth crank.

Further, the effective length of the feed lifting rock shaft crank is changed by the feed lifting rock height adjusting mechanism, and the effective length of the feed lifting rock shaft crank is the distance between the connecting center of the feed lifting rock shaft connecting rod and the feed lifting rock shaft crank and the rotation center of the feed lifting rock shaft.

As described above, the method for adjusting the height of the lifting teeth for the sewing machine according to the present invention has the following advantages:

according to the application, the transmission efficiency of the first feed lifting tooth transmission assembly is changed to change the swing amplitude of the main shaft which drives the feed lifting tooth shaft to swing through the first feed lifting tooth transmission assembly, so that the height of the feed lifting tooth is adjusted, the universality of the sewing machine is greatly improved, the adaptability of the sewing machine to different sewing materials is greatly enhanced, and the competitiveness of products is improved; particularly, the adjustment of the height of the lifting tooth is realized by changing the swing of the lifting tooth shaft, the needle pitch cannot be changed while the height of the lifting tooth is adjusted, and the sewing quality is ensured.

Drawings

Fig. 1 is a schematic view showing a structure of a sewing machine in the prior art.

Fig. 2 is a schematic diagram of the motion track of the feeding tooth in fig. 1.

Fig. 3 is a schematic diagram of a change of a motion track of a feed dog caused by changing the installation position of a feed dog fork on a feed dog shaft in the prior art.

Fig. 4 is a schematic diagram of a movement track of a feeding tooth with an excessively high tooth lifting height in the prior art.

FIG. 5 is a schematic view of a first embodiment of a sewing machine according to the present application.

Fig. 6 to 8 are schematic views illustrating connection among the main shaft, the cam, and the cam adjusting assembly in fig. 5.

Fig. 9 is a schematic diagram of adjusting the feed dog lifting height of fig. 5.

FIG. 10 is a schematic structural view of a second embodiment of a sewing machine according to the present application.

FIG. 11 is a schematic view of the connection between the main shaft, the cam, and the cam adjustment assembly of FIG. 10.

Fig. 12 is a schematic view of the adjustment of the feed dog lifting height of fig. 10.

Fig. 13 and 14 are schematic structural views of a third embodiment of the sewing machine in the application at different viewing angles.

(wherein FIGS. 13 and 14 contain a first embodiment of an adjustment drive assembly.)

Fig. 15 is an enlarged view of circle a of fig. 13.

FIG. 16 is a schematic view showing the connection among the main shaft, the cam and the cam link in the third embodiment of the sewing machine.

FIG. 17 is a schematic structural view of a second embodiment of an adjustment driving assembly in a third embodiment of a sewing machine.

FIG. 18 is a schematic structural view of a third embodiment of an adjustment driving assembly in a third embodiment of a sewing machine.

Fig. 19 is a schematic structural view of a fourth embodiment of an adjustment driving assembly in a third embodiment of a sewing machine.

Fig. 20 is a schematic structural view of a fifth embodiment of an adjusting drive assembly in a third embodiment of a sewing machine.

FIG. 21 is a schematic view of a third embodiment of a sewing machine.

Fig. 22 is a schematic structural view of a fourth embodiment of the sewing machine of the present application.

FIG. 23 is a schematic diagram of the first embodiment of the first feed dog transmission assembly and the adjustment drive assembly of FIG. 22.

FIG. 24 is a schematic structural view of a second embodiment of an adjustment driving assembly in a fourth embodiment of a sewing machine.

FIG. 25 is a schematic view of a fourth embodiment of the sewing machine.

Fig. 26 is a schematic structural view of a fifth embodiment of the sewing machine of the present application.

Fig. 27 is an enlarged view of circle B of fig. 26.

Fig. 28 to 30 are schematic connection views of the first tooth lifting transmission assembly and the first adjustment driving assembly in fig. 26.

(the feed lifting shaft is omitted in FIG. 30.)

FIG. 31 is a schematic structural view of a first embodiment of an adjustment driving assembly in a fifth embodiment of a sewing machine.

FIG. 32 is a schematic structural view of a second embodiment of an adjustment driving assembly in a fifth embodiment of a sewing machine.

FIG. 33 is a schematic view of a feed lifting height adjusting mechanism in a fifth embodiment of the sewing machine.

Fig. 34 is a graph showing a change in the movement locus of the feed dog in the present application.

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 used for descriptive purposes only and are not intended to limit the scope of the present invention, and the relative relationship between the terms may be changed or adjusted without substantial technical change.

The application provides a feed lifting tooth height adjusting method for a sewing machine, wherein the sewing machine is a flat sewing machine. 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 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; the moving direction of the sewing material when the sewing machine sews is defined as the front direction.

The invention relates to a feed lifting height adjusting method which is used for a sewing machine; as shown in fig. 5, 10, 14, 22 or 26, the sewing machine has a main shaft 10 extending left and right, a feed dog shaft 20 parallel to the main shaft 10, a feed dog 30 mounted on the feed dog 30, a first feed dog transmission assembly connected between the main shaft 10 and the feed dog shaft 20, and a second feed dog transmission assembly connected between the feed dog shaft 20 and the feed dog 30. When the sewing machine is used for sewing normally, a main motor in the sewing machine drives a main shaft 10 to rotate, the main shaft 10 drives a feed lifting tooth shaft 20 to swing back and forth periodically through a first feed lifting tooth transmission assembly, the feed lifting tooth shaft 20 drives a feed lifting tooth frame 30 and a feed feeding tooth 40 to move back and forth up and down through a second feed lifting tooth transmission assembly, and the first feed lifting tooth transmission assembly, the feed lifting tooth shaft 20 and the second feed lifting tooth transmission assembly form a feed lifting tooth mechanism of the sewing machine. Therefore, the main shaft 10 drives the feeding tooth 40 fixed on the tooth frame 30 to do a periodical up-and-down reciprocating motion through the tooth lifting mechanism; the motion amplitude of the feeding tooth 40 moving up and down is directly related to the swing amplitude of the feed lifting tooth shaft 20.

Further, the lifting tooth height adjusting method comprises the following steps: 1) The sewing machine is provided with a feed lifting tooth height adjusting mechanism, and the feed lifting tooth height adjusting mechanism acts on the first feed lifting tooth transmission assembly; 2) When the height of the feed lifting teeth needs to be adjusted, the feed lifting teeth height adjusting mechanism acts to change the transmission efficiency of the first feed lifting teeth transmission component, so that the swing amplitude of the spindle 10 for driving the feed lifting teeth shaft 20 to swing through the first feed lifting teeth transmission component is changed, the amplitude of the feed lifting teeth shaft 20 for driving the tooth frame 30 and the feed lifting teeth 40 to reciprocate up and down through the second feed lifting teeth transmission component is changed, and the height of the feed lifting teeth 40 is adjusted. In particular, the adjustment of the lifting tooth height in the application is realized by changing the swing amplitude of the lifting tooth shaft 20, the needle pitch is not changed while the lifting tooth height is adjusted, and the sewing quality is ensured. Specifically, in the movement locus diagram of the feed dog 40 shown in fig. 34, the Z direction indicates the tooth lifting height of the feed dog 40, the X direction indicates the needle pitch, and L indicates the upper surface of the needle plate; the tooth lifting height corresponding to the curve S1 in fig. 34 is 1.0mm. When the swing amplitude of the feed lifting tooth shaft 20 is reduced by the feed lifting tooth height adjusting mechanism, the motion trail of the feed lifting tooth 40 is changed from the curve S1 in fig. 34 to the curve S3, the feed lifting tooth height of the feed lifting tooth 40 is reduced from 1.0mm corresponding to the curve S1 to 0.8mm corresponding to the curve S3, and the feed lifting tooth height adjusting mechanism is suitable for sewing thin materials and can improve the wrinkling phenomenon of sewing materials. When this application increases the swing of feed lifting teeth axle 20 through feed lifting teeth height adjustment mechanism, the motion trail of pay-off tooth 40 changes into curve S2 by curve S1 in fig. 34, and the feed lifting teeth height of pay-off tooth 40 is increased for the 1.2mm that curve S2 corresponds by the 1.0mm that curve S1 corresponds, and it is fit for making thick material and crossing the stalk sewing, can effectively improve pay-off efficiency for the pay-off is more smooth and easy. As can be seen from fig. 34: in the application, when the feed dog height of the feed dog 40 is adjusted, the motion track of the feed dog 40 does not move up or down as a whole, but only changes the amplitude in the vertical direction, but does not change the amplitude in the front-back direction, so that the needle pitch of the sewing machine is kept unchanged in the process of adjusting the feed dog height, the sewing quality is not influenced, and the phenomenon that the feed dog 40 drags back sewing materials is avoided. Therefore, the feed dog height of the feed dog 40 can be adjusted within a certain range, stepless adjustment is achieved, the needle pitch cannot be changed while the feed dog height is adjusted, the sewing machine can have different feed dog heights according to sewing materials of different specifications, the sewing quality can be effectively guaranteed, the adaptability of the sewing machine to different sewing materials is improved, the universality of the sewing machine is greatly improved, and the competitiveness of products is improved.

Further, as shown in fig. 5, the first lifting tooth transmission assembly includes a lifting tooth eccentric 51, a lifting tooth connecting rod 52, and a lifting tooth crank 53 fixedly locked on the lifting tooth shaft 20 by a screw, the lifting tooth eccentric 51 is connected with the main shaft 10, and both ends of the lifting tooth connecting rod 52 are respectively connected with the lifting tooth eccentric 51 and the lifting tooth crank 53. The mode that the feed lifting height adjusting mechanism changes the transmission efficiency of the first feed lifting transmission assembly can be as follows: 1. changing the eccentric amount W of the lifting tooth between the matching center O1 of the lifting tooth eccentric wheel 51 and the lifting tooth connecting rod 52 and the rotation center O2 of the main shaft 10; 2. the transmission efficiency between the feed lifting rock connecting rod 52 and the feed lifting rock crank 53 is changed; 3. the effective length of the feed lifting rock crank 53 is changed, and the effective length of the feed lifting rock crank 53 is the distance between the connecting center of the feed lifting rock connecting rod 52 and the feed lifting rock crank 53 and the rotation center of the feed lifting rock shaft 20. Therefore, the matching structure of the first feed lifting tooth transmission assembly and the feed lifting tooth height adjusting mechanism can have multiple embodiments, and accordingly, the sewing machine can have multiple embodiments. Several preferred embodiments of the sewing machine are provided below.

The first embodiment of the sewing machine: the feed lifting height adjusting mechanism changes the transmission efficiency of the first feed lifting transmission assembly by changing the feed lifting eccentric amount W between the matching center O1 of the feed lifting eccentric wheel 51 and the feed lifting connecting rod 52 and the rotation center O2 of the main shaft 10.

As shown in fig. 5 to 9, in the first embodiment of the sewing machine, the cam 51 is sleeved on the main shaft 10, the cam height adjusting mechanism is a cam eccentric adjusting assembly 60, the cam eccentric adjusting assembly 60 is connected to both the main shaft 10 and the cam 51, and the right end of the main shaft 10 is fixedly provided with the hand wheel 130. The tooth lifting eccentric adjusting assembly 60 comprises a ratchet wheel 61, an adjusting slide piece 62 with a pawl part 621 at the lower end, an adjusting eccentric wheel 63, an adjusting slide block 64, a fixed slide block 65 and a tooth lifting adjusting button 66, wherein the ratchet wheel 61, the adjusting slide piece 62, the adjusting eccentric wheel 63, the tooth lifting eccentric wheel 51 and the fixed slide block 65 are sequentially arranged from left to right along the axial direction of the main shaft 10. Wherein, the ratchet wheel 61 and the fixed slide block 65 are fixedly sleeved on the main shaft 10 through screws; a circle of ratchets are arranged at the left end of the ratchet wheel 61; a first sliding groove 631 is formed in the right end face of the adjusting eccentric wheel 63, and the adjusting slide piece 62 is located in the first sliding groove 631 and is in sliding fit with the first sliding groove 631; a long groove is formed in the adjusting slide piece 62, the extending direction of the long groove is consistent with the extending direction of the first slide groove 631, and when the adjusting slide piece 62 slides in the first slide groove 631, the main shaft 10 is prevented from interfering with the sliding of the adjusting slide piece 62 through the long groove; the left end of the adjusting eccentric wheel 63 is provided with a first eccentric part 632 extending leftwards in the direction back to the adjusting slide sheet 62; the left end of the lifting eccentric wheel 51 is provided with a second sliding groove 511 which is in sliding fit with the fixed sliding block 65, and the right end of the lifting eccentric wheel 51 is provided with a second eccentric part 512 which extends rightwards away from the fixed sliding block 65; the inner periphery of the first eccentric part 632 is matched with the main shaft 10, the outer periphery of the first eccentric part 632 is matched with the inner periphery of the adjusting slide block 64, the inner periphery of the second eccentric part 512 is matched with the adjusting slide block 64, and the outer periphery of the second eccentric part 512 is matched with the inner periphery of the upper end of the tooth lifting connecting rod 52, namely the main shaft 10, the first eccentric part 632 of the adjusting eccentric wheel 63, the adjusting slide block 64, the second eccentric part 512 of the tooth lifting eccentric wheel 51 and the upper end of the tooth lifting connecting rod 52 are sequentially sleeved and matched from inside to outside along the radial direction of the main shaft 10; a first fitting plane 641 is disposed on the outer peripheral surface of the adjustment slider 64, and a second fitting plane 513 fitted with the first fitting plane 641 is disposed on the inner peripheral surface of the second eccentric portion 512; the tooth lifting adjusting button 66 is provided above the adjusting slide 62, and can act on the adjusting slide 62 to slide the adjusting slide 62 in the first slide groove 631.

In the first embodiment of the sewing machine, when the height of the feed dog 40 is not required to be adjusted, the feed dog adjusting button 66 does not act on the adjusting slide piece 62, the position of the adjusting slide piece 62 in the first slide groove 631 is not changed, and at this time, the pawl 621 of the adjusting slide piece 62 is engaged with the ratchet teeth of the ratchet wheel 61. When the sewing machine sews normally, the main shaft 10 and the ratchet wheel 61 are fixed and are relatively static, the adjusting slide piece 62 is static relative to the main shaft 10 through the engagement of the pawl part 621 on the adjusting slide piece 62 and the ratchet on the ratchet wheel 61, the adjusting slide piece 62 is positioned in the first slide groove 631 of the adjusting eccentric wheel 63, the first slide groove 631 simultaneously plays a limiting role, so the adjusting eccentric wheel 63 is static relative to the main shaft 10 along with the adjusting slide piece 62; meanwhile, the main shaft 10 and the fixed slide block 65 are fixed and are relatively static, and the fixed slide block 65 is positioned in the second sliding groove 511 of the cam 51, so that the cam 51 is static relative to the main shaft 10 along with the fixed slide block 65; therefore, the ratchet wheel 61, the adjusting slide piece 62, the adjusting eccentric 63, the adjusting slide block 64, the fixed slide block 65 and the cam 51 rotate together with the main shaft 10, the cam connecting rod 52 is driven by the cam eccentric 51 to move, the cam connecting rod 52 drives the cam shaft 20 to periodically reciprocate through the cam crank 53, and the cam shaft 20 drives the tooth rack 30 and the feeding tooth 40 to periodically reciprocate up and down through the second cam transmission assembly. Because the adjusting eccentric wheel 63 and the cam 51 are relatively static, the cam eccentricity W between the cam eccentric wheel 51 and the cam connecting rod 52 and the rotation center O2 of the main shaft 10 is kept constant, so that the vertical movement amplitude of the feeding tooth 40 is constant, and the cam height is kept constant. When the height of the lifting teeth of the feeding teeth 40 needs to be adjusted, the sewing machine stops, the lifting teeth adjusting button 66 is pressed, the lower end of the lifting teeth adjusting button 66 acts on the adjusting sliding piece 62, the adjusting sliding piece 62 is enabled to slide downwards along the first sliding groove 631, and the ratchet claw part 621 on the adjusting sliding piece 62 is enabled to be separated from the ratchet on the ratchet wheel 61; then, the hand wheel 130 is manually rotated to drive the main shaft 10 to rotate together, the main shaft 10 drives the fixed slide block 65 and the tooth lifting eccentric wheel 51 to rotate together, under the mutual matching action of the first matching plane 641 and the second matching plane 513, the adjusting slide block 64 rotates together with the second eccentric part 512 of the tooth lifting eccentric wheel 51, and the adjusting slide sheet 62 is stationary under the limit of the tooth lifting adjusting button 66, so the adjusting eccentric wheel 63 is stationary together with the adjusting slide sheet 62; therefore, when the main shaft 10 is rotated by rotating the hand wheel 130, the fixed slider 65 drives the second eccentric portion 512 of the cam 51 to rotate relatively around the first eccentric portion 632 of the adjusting eccentric 63, as shown in fig. 9, so as to change the cam eccentricity W between the matching center O1 of the cam eccentric 51 and the cam connecting rod 52 and the rotation center O2 of the main shaft 10, thereby directly changing the swing amplitude of the main shaft 10 driving the cam shaft 20 to swing, and realizing the adjustment of the cam height of the feeding cam 40.

Further, as shown in fig. 5 to 8, a pre-tightening torsion spring 69 is mounted on a right end surface of the adjusting eccentric 63 facing the ratchet wheel 61, and two ends of the pre-tightening torsion spring 69 are respectively connected with the adjusting eccentric 63 and the adjusting slide 62; when the lifting tooth adjusting button 66 is not pressed down, the ratchet teeth on the ratchet wheel 61 and the ratchet pawl part 621 on the adjusting slide piece 62 are kept in an engaged state by pre-tightening the spring force of the torsion spring 69; when the lifting tooth adjusting button 66 is pressed, the adjusting slide piece 62 is moved downwards against the spring force of the pre-tightening torsion spring 69, and the pawl part 621 on the adjusting slide piece 62 is disengaged from the ratchet teeth on the ratchet wheel 61.

The second embodiment of the sewing machine: the feed-lifting height adjusting mechanism changes the transmission efficiency of the first feed-lifting transmission assembly by changing the feed-lifting eccentricity W between the fitting center O1 of the feed-lifting eccentric wheel 51 and the feed-lifting connecting rod 52 and the rotation center O2 of the main shaft 10.

The difference between the second sewing machine embodiment and the first sewing machine embodiment is that the structure of the feed lifting eccentric adjusting assembly 60 is different; therefore, in the second embodiment of the sewing machine, as shown in fig. 10 to 12, the cam 51 is sleeved on the main shaft 10, the cam height adjusting mechanism is a cam eccentric adjusting assembly 60, the cam eccentric adjusting assembly 60 is connected to the main shaft 10 and the cam 51, and the right end of the main shaft 10 is fixedly provided with the hand wheel 130. The tooth lifting eccentric adjusting assembly 60 comprises a ratchet wheel 61, an adjusting slide piece 62 with a pawl part 621 at the lower end, an adjusting eccentric wheel 63, a small eccentric wheel 67, a fixed wheel 68 and a tooth lifting adjusting button 66, wherein the ratchet wheel 61, the adjusting slide piece 62, the adjusting eccentric wheel 63, the tooth lifting eccentric wheel 51 and the fixed wheel 68 are sequentially arranged from left to right along the axial direction of the main shaft 10. Wherein, the ratchet wheel 61 and the fixed wheel 68 are fixedly sleeved on the main shaft 10 through screws; a circle of ratchets are arranged at the left end of the ratchet wheel 61; a first sliding groove 631 is formed in the right end face of the adjusting eccentric wheel 63, and the adjusting slide piece 62 is located in the first sliding groove 631 and is in sliding fit with the first sliding groove 631; the adjusting slide vane 62 is provided with a long groove, the extending direction of the long groove is consistent with the extending direction of the first slide groove 631, and when the adjusting slide vane 62 slides in the first slide groove 631, the main shaft 10 is prevented from interfering the sliding of the adjusting slide vane 62 through the long groove; the left end of the adjusting eccentric wheel 63 is provided with a first eccentric part 632 extending leftwards back to the direction of the adjusting slide sheet 62; the left end of the tooth lifting eccentric wheel 51 is provided with a mounting hole 514 for mounting the small eccentric wheel 67, and the right end of the tooth lifting eccentric wheel 51 is provided with a second eccentric part 512 extending rightwards in a direction opposite to the mounting hole 514; an eccentric bulge protruding rightwards is arranged on the right end face of the fixed wheel 68 and matched with an eccentric hole in the small eccentric wheel 67, and the eccentric hole in the small eccentric wheel 67 is arranged eccentrically relative to the center of the small eccentric wheel 67; the inner periphery of the first eccentric part 632 is matched with the main shaft 10, the outer periphery of the first eccentric part 632 is matched with the inner periphery of the second eccentric part 512, and the outer periphery of the second eccentric part 512 is matched with the inner periphery of the upper end of the lifting tooth connecting rod 52, namely the main shaft 10, the first eccentric part 632 of the adjusting eccentric wheel 63, the second eccentric part 512 of the lifting tooth eccentric wheel 51 and the lifting tooth connecting rod 52 are sequentially sleeved from inside to outside along the radial direction of the main shaft 10; the tooth lifting adjusting button 66 is provided above the adjusting slide 62, and can act on the adjusting slide 62 to slide the adjusting slide 62 in the first slide groove 631.

In the second embodiment of the sewing machine, when the height of the feed dog 40 is not required to be adjusted, the feed dog adjusting button 66 does not act on the adjusting slide piece 62, the position of the adjusting slide piece 62 in the first slide groove 631 is not changed, and at this time, the pawl 621 of the adjusting slide piece 62 is engaged with the ratchet teeth of the ratchet wheel 61. When the sewing machine is used for normal sewing, the main shaft 10 and the ratchet wheel 61 are fixed and are relatively static, the adjusting sliding piece 62 is static relative to the main shaft 10 through the engagement of the pawl part 621 on the adjusting sliding piece 62 and the ratchet on the ratchet wheel 61, the adjusting sliding piece 62 is positioned in the first sliding groove 631 of the adjusting eccentric wheel 63, and the first sliding groove 631 simultaneously plays a limiting role, so that the adjusting eccentric wheel 63 is static relative to the main shaft 10 along with the adjusting sliding piece 62; meanwhile, the main shaft 10 and the fixed wheel 68 are fixed and are relatively static, and the fixed wheel 68 is relatively static with the eccentric cam 51 through the small eccentric wheel 67, so that the eccentric cam 51 is static relative to the main shaft 10 along with the fixed wheel 68; therefore, the ratchet wheel 61, the adjusting slide plate 62, the adjusting eccentric wheel 63, the fixed wheel 68 and the cam gear wheel 51 rotate together with the main shaft 10, the cam gear wheel 51 drives the cam gear connecting rod 52 to move, the cam gear connecting rod 52 drives the cam gear shaft 20 to periodically reciprocate through the cam gear crank 53, and the cam gear shaft 20 drives the tooth rack 30 and the feeding tooth 40 to periodically reciprocate up and down through the second cam gear transmission component. Because the adjusting eccentric wheel 63 and the cam 51 are relatively static, the cam eccentricity W between the cam eccentric wheel 51 and the cam connecting rod 52 and the rotation center O2 of the main shaft 10 is kept constant, so that the vertical movement amplitude of the feeding tooth 40 is constant, and the cam height is kept constant. When the lifting tooth height of the feeding tooth 40 needs to be adjusted, the sewing machine stops, the lifting tooth adjusting button 66 is pressed, the lower end of the lifting tooth adjusting button 66 acts on the adjusting slide piece 62, the adjusting slide piece 62 is driven to slide downwards along the first slide groove 631, and the ratchet claw part 621 on the adjusting slide piece 62 is driven to be separated from the ratchet on the ratchet wheel 61; then, the hand wheel 130 is manually rotated to drive the main shaft 10 to rotate together, as shown in fig. 12, the main shaft 10 drives the fixed wheel 68 to rotate together, the fixed wheel 68 drives the tooth lifting eccentric wheel 51 to rotate through the matching of the eccentric protrusion and the small eccentric wheel 67, but the rotation amplitude of the tooth lifting eccentric wheel 51 is different from that of the fixed wheel 68, and the adjusting slide piece 62 is stationary under the limit of the tooth lifting adjusting button 66, so the adjusting eccentric wheel 63 is stationary together with the adjusting slide piece 62; therefore, by rotating the hand wheel 130 to rotate the main shaft 10, the eccentric amount W of the feed lifting teeth between the matching center O1 of the eccentric cam 51 and the feed lifting teeth connecting rod 52 and the rotation center O2 of the main shaft 10 can be changed, so that the swing amplitude of the main shaft 10 driving the feed lifting teeth shaft 20 to swing is directly changed, and the feed lifting teeth height of the feed lifting teeth 40 is adjusted. In fig. 12, point a is the center of the eccentric projection of the cam 51, i.e., the center of the eccentric hole of the small eccentric 67, point B is the center of the small eccentric 67, and point C is the center of the first eccentric portion 632.

Further, as shown in fig. 10 and 11, a pre-tightening torsion spring 69 is mounted on a right end surface of the adjusting eccentric 63 facing the ratchet wheel 61, and two ends of the pre-tightening torsion spring 69 are respectively connected with the adjusting eccentric 63 and the adjusting slide 62; when the lifting tooth adjusting button 66 is not pressed down, the ratchet teeth on the ratchet wheel 61 and the ratchet pawl part 621 on the adjusting slide piece 62 are kept in an engaged state by pre-tightening the spring force of the torsion spring 69; when the lifting tooth adjusting button 66 is pressed, the adjusting slide piece 62 is moved downwards against the spring force of the pre-tightening torsion spring 69, and the pawl part 621 on the adjusting slide piece 62 is disengaged from the ratchet teeth on the ratchet wheel 61.

The third embodiment of the sewing machine: the feed lifting teeth height adjusting mechanism changes the transmission efficiency of the first feed lifting teeth transmission component by changing the transmission efficiency between the feed lifting teeth connecting rod 52 and the feed lifting teeth crank 53.

In the third embodiment of the sewing machine, as shown in fig. 13 to 16, the feed lifting height adjusting mechanism includes an adjusting drive assembly and an adjusting operation portion 120; the feed lifting eccentric wheel 51 is locked and fixed on the main shaft 10 through a screw; the upper end of the feed lifting connecting rod 52 is rotatably sleeved on the periphery of the feed lifting eccentric wheel 51; the first feed dog transmission assembly further comprises a feed dog adjusting seat 54, a first swinging plate 55 and a second swinging plate 56, and the lower end of the feed dog connecting rod 52 is connected with the feed dog crank 53 through the feed dog adjusting seat 54, the first swinging plate 55 and the second swinging plate 56: the lifting tooth adjusting seat 54 is provided with a first fixed swing fulcrum Q1, the lower end of the lifting tooth connecting rod 52, the front end of the first swing plate 55 and the front end of the second swing plate 56 are coaxially hinged through a pin extending left and right, the rear end of the first swing plate 55 is hinged with the lifting tooth adjusting seat 54 through a pin extending left and right, and the rear end of the second swing plate 56 is hinged with the lifting tooth crank 53 through a pin extending left and right; the adjusting operation portion 120 is connected to the lifting tooth adjusting base 54 through an adjusting driving assembly, and is configured to drive the lifting tooth adjusting base 54 to rotate around the first fixed swing fulcrum Q1, so as to change the position angle of the lifting tooth adjusting base 54.

In the third embodiment of the sewing machine, when the sewing machine normally works, the adjusting operation part 120 does not act, the position angle of the feed lifting tooth adjusting seat 54 is kept unchanged under the limit action of the adjusting operation part 120 and the adjusting drive component, as shown in fig. 21, the main shaft 10 drives the feed lifting tooth eccentric wheel 51 to rotate together and drives the feed lifting tooth connecting rod 52 to move, the feed lifting tooth connecting rod 52 drives the feed lifting tooth crank 53 to swing back and forth through the first swing plate 55 and the second swing plate 56, the feed lifting tooth shaft 20 swings back and forth along with the feed lifting tooth crank 53, and the feed lifting tooth shaft 20 drives the feed rack 30 and the feed feeding tooth 40 to reciprocate up and down through the second feed lifting tooth transmission component. The position angle of the feed lifting adjusting seat 54 is directly related to the swing amplitude of the feed lifting shaft 20 in one period; because the position angle of the feed lifting tooth adjusting seat 54 is kept unchanged, the transmission efficiency between the feed lifting tooth eccentric wheel 51 and the feed lifting tooth shaft 20 is also kept unchanged, so that the swinging amplitude of the main shaft 10 driving the feed lifting tooth shaft 20 to swing is kept unchanged, and the feed lifting tooth height of the feed feeding tooth 40 is also kept constant and unchanged. When the lifting tooth height needs to be adjusted, the adjusting operation part 120 acts to drive the lifting tooth adjusting seat 54 to rotate around the first fixed swing fulcrum Q1 through the adjusting driving component, so as to change the position angle of the lifting tooth adjusting seat 54, as shown in fig. 21, thereby changing the transmission efficiency between the lifting tooth eccentric wheel 51 and the lifting tooth shaft 20, changing the swing amplitude of the main shaft 10 driving the lifting tooth shaft 20 to swing, and realizing the adjustment of the lifting tooth height of the feeding tooth 40.

Preferably, as shown in fig. 15, the lift tooth adjusting seat 54 has two seat arm portions 541 symmetrically arranged left and right, two first swing plates 55 and two second swing plates 56 are located between the two seat arm portions 541, the two second swing plates 56 are distributed on left and right sides of the lower end of the lift tooth link 52, and one first swing plate 55 is distributed between the second swing plates 56 and the seat arm portions 541. Each of the holder arm portions 541 is rotatably mounted to a support shaft 57 extending left and right, and the support shaft 57 is fixed to the sewing machine housing and constitutes a first fixed swing fulcrum Q1 of the feed adjustment holder 54.

Further, as shown in fig. 13 and 14, the adjustment driving assembly includes an adjustment lever 110 and a first adjustment crank 71 having a second fixed swing fulcrum Q2, the adjustment lever 110 is perpendicular to the main shaft 10 and extends forward and backward along the direction in which the feed dog 40 transfers the fabric forward, the adjustment operating portion 120 is connected to the rear end of the adjustment lever 110 to drive the adjustment lever 110 to move forward and backward, the front end of the adjustment lever 110 is connected to the first adjustment crank 71 to drive the first adjustment crank 71 to rotate around the second fixed swing fulcrum Q2, the first adjustment crank 71 is connected to the feed dog adjustment base 54 to drive the feed dog adjustment base 54 to rotate around the first fixed swing fulcrum Q1. Preferably, the first adjusting crank 71 is rotatably mounted to a first crank shaft 72 extending left and right, the first crank shaft 72 being fixed to the sewing machine housing and constituting a second fixed swing fulcrum Q2 of the first adjusting crank 71. The adjusting lever 110 is mounted to the sewing machine housing to be movable back and forth, such as: the adjusting lever 110 is a screw which is screwed in the sewing machine case, and the adjusting operation part 120 is a knob fixed at the rear end of the adjusting lever 110; the knob is rotated to drive the adjusting lever 110 to rotate together, and the adjusting lever 110 moves forward or backward when rotating. Preferably, the connection mode of the adjusting rod 110 and the first adjusting crank 71 can be an abutting fit, and can also be connected through a first connecting sleeve 75; the first adjusting crank 71 and the lifting tooth adjusting seat 54 may be directly connected or connected through a first adjusting link 73. Therefore, the adjustment driving assembly has a plurality of embodiments based on different connection structures between the adjustment lever 110 and the first adjustment crank 71 and between the first adjustment crank 71 and the lifting teeth adjustment seat 54. Five preferred embodiments of the adjustment drive assembly are provided below.

First embodiment of the adjusting driving assembly, as shown in fig. 13 and 14, the first embodiment of the adjusting driving assembly includes an adjusting lever 110 screwed into the sewing machine housing, a first adjusting crank 71 having a second fixed swing fulcrum Q2, and a first adjusting link 73, wherein a front end of the adjusting lever 110 is in abutting engagement with a rear end surface of an upper section of the first adjusting crank 71, a lower end of the first adjusting crank 71 is hinged to an upper end of the first adjusting link 73 through a pin extending in the left-right direction, and a lower end of the first adjusting link 73 is hinged to the lifting tooth adjusting seat 54 through a pin extending in the left-right direction. When the knob constituting the adjustment operation portion 120 is rotated, the adjustment lever 110 rotates together with the knob, the adjustment lever 110 moves in the front-rear direction when rotating, the first adjustment crank 71 is driven to rotate around the second fixed swing fulcrum Q2, the first adjustment crank 71 drives the tooth lifting adjustment base 54 to rotate around the first fixed swing fulcrum Q1 through the first adjustment connecting rod 73, the position angle of the tooth lifting adjustment base 54 is changed, and the adjustment of the tooth lifting height is realized. In order to ensure that the adjusting rod 110 and the first adjusting crank 71 can be reliably abutted and matched all the time, as shown in fig. 13 and 14, the first adjusting driving assembly embodiment further comprises a first pressing spring 74, wherein the upper end of the first pressing spring 74 is connected with the first adjusting connecting rod 73, and the lower end of the first pressing spring 74 is connected with the sewing machine shell; the first pressing spring 74 applies an acting force to the first adjusting crank 71 through the first adjusting link 73, and ensures the reliability of the contact between the first adjusting crank 71 and the front end of the adjusting lever 110.

Second embodiment of the adjustment drive assembly as shown in fig. 17, the second embodiment of the adjustment drive assembly is different from the first embodiment of the adjustment drive assembly in that: 1. the first hold-down spring 74 is connected differently; 2. the first adjusting crank 71 is assembled differently from the first adjusting link 73. In the first embodiment of the adjustment driving assembly, as shown in fig. 14, the hinge point of the first adjustment crank 71 and the first adjustment connecting rod 73 is located at the rear lower part of the first crank shaft 72, and the upper end of the first hold-down spring 74 is connected with the first adjustment connecting rod 73; in the second embodiment of the adjustment driving assembly, as shown in fig. 17, the hinge point between the first adjustment crank 71 and the first adjustment connecting rod 73 is located at the front lower part of the first crank axle 72, the upper end of the first pressing spring 74 is connected with the first adjustment crank 71 and suspended at the lower part of the first adjustment crank 71, and the first pressing spring 74 directly applies force to the first adjustment crank 71.

Third adjustment drive assembly embodiment as shown in fig. 18, the third adjustment drive assembly embodiment differs from the first adjustment drive assembly embodiment in that: 1. the first hold-down spring 74 is connected differently; 2. the first adjusting crank 71 is assembled differently from the first adjusting link 73. In the third embodiment of the adjusting driving assembly, as shown in fig. 18, a hinge point of the first adjusting crank 71 and the first adjusting connecting rod 73 is also located at a front lower portion of the first crank shaft 72, the third embodiment of the adjusting driving assembly further includes a first hanging plate 76 fixed to the sewing machine housing, one end of the first pressing spring 74 is connected to the first hanging plate 76, and the other end is connected to an upper end of the first adjusting crank 71, so that the first pressing spring 74 is connected to the sewing machine housing through the first hanging plate 76, the first pressing spring 74 is hung on an upper portion of the first adjusting crank 71, and the first pressing spring 74 directly applies an acting force to the first adjusting crank 71.

Fourth embodiment of the adjusting driving assembly, as shown in fig. 19, the fourth embodiment of the adjusting driving assembly includes an adjusting lever 110 screwed in the sewing machine housing, a first connecting sleeve 75 rotatably mounted at the front end of the adjusting lever 110, a first adjusting crank 71 having a second fixed swing fulcrum Q2, and a first adjusting link 73; the adjusting rod 110 and the first connecting sleeve 75 can rotate relatively but cannot move relatively; the front end of the first connecting sleeve 75 is provided with a notch, the upper end of the first adjusting crank 71 is positioned in the notch of the first connecting sleeve 75 and is provided with a third sliding groove, the upper end of the first adjusting crank 71 is hinged with the front end of the first connecting sleeve 75 through a pin extending leftwards and rightwards, the pin penetrates through the third sliding groove and is in sliding fit with the third sliding groove; the lower end of the first adjusting crank 71 is hinged with the upper end of the first adjusting connecting rod 73 through a pin extending left and right, and the lower end of the first adjusting connecting rod 73 is hinged with the tooth lifting adjusting seat 54 through a pin extending left and right. When the knob forming the adjusting operation portion 120 is rotated, the adjusting lever 110 rotates together with the knob, the adjusting lever 110 moves in the front-rear direction when rotating, the first connecting sleeve 75 is driven to move together, the first adjusting crank 71 is driven to rotate around the second fixed swing fulcrum Q2 through the first connecting sleeve 75, the first adjusting crank 71 drives the lifting tooth adjusting seat 54 to rotate around the first fixed swing fulcrum Q1 through the first adjusting connecting rod 73, the position angle of the lifting tooth adjusting seat 54 is changed, and the adjustment of the lifting tooth height is realized. Fourth embodiment of the adjustment drive assembly with respect to the first embodiment of the adjustment drive assembly, the connection between the adjustment lever 110 and the first adjustment crank 71 is changed without the abutting engagement of the first embodiment of the adjustment drive assembly, and the first compression spring 74 of the first embodiment of the adjustment drive assembly is eliminated.

Fifth embodiment of the adjusting driving assembly, as shown in fig. 20, the fifth embodiment of the adjusting driving assembly is different from the fourth embodiment of the adjusting driving assembly in that: the connection mode of the first adjusting crank 71 and the lifting tooth adjusting seat 54 is changed; the fifth adjustment drive assembly embodiment eliminates the first adjustment link 73 of the fourth adjustment drive assembly embodiment. Specifically, as shown in fig. 20, the first adjusting crank 71 and the tooth lifting adjusting seat 54 are hinged by a first connecting pin 77 extending left and right, a fourth sliding slot 542 is formed on the seat arm 541 of the tooth lifting adjusting seat 54, and the first connecting pin 77 is located in the fourth sliding slot 542 and is in sliding fit with the fourth sliding slot 542.

The fourth embodiment of the sewing machine: the feed lifting teeth height adjusting mechanism changes the transmission efficiency of the first feed lifting teeth transmission component by changing the transmission efficiency between the feed lifting teeth connecting rod 52 and the feed lifting teeth crank 53.

In the fourth embodiment of the sewing machine, as shown in fig. 22 and 23, the feed lifting height adjusting mechanism includes a second adjusting link 81, an adjusting drive assembly, and an adjusting operation portion 120; the feed lifting eccentric wheel 51 is locked and fixed on the main shaft 10 through a screw; the upper end of the feed lifting connecting rod 52 is rotatably sleeved on the periphery of the feed lifting eccentric wheel 51; the first feed dog transmission assembly further comprises a feed dog connecting plate 58, the lower end of the feed dog connecting rod 52, one end of the feed dog connecting plate 58 and one end of the second adjusting connecting rod 81 are coaxially hinged through a pin extending left and right, the other end of the feed dog connecting plate 58 is hinged with the feed dog crank 53 through a pin extending left and right, and the adjusting operation part 120 acts on the second adjusting connecting rod 81 through the adjusting driving assembly and is used for changing the position of the second adjusting connecting rod 81.

In the fourth embodiment of the sewing machine, as shown in fig. 25, the cam eccentric 51, the cam connecting rod 52, the second adjusting connecting rod 81, the cam connecting plate 58, and the cam crank 53 form a compound four-bar mechanism. When the sewing machine normally works, the adjusting operation part 120 does not act, the position angle of the second adjusting connecting rod 81 is fixed under the action of the adjusting operation part 120 and the adjusting driving component, the transmission efficiency of the composite four-bar mechanism is kept unchanged, the main shaft 10 drives the feed lifting tooth connecting rod 52 to move through the feed lifting tooth eccentric wheel 51, the feed lifting tooth connecting rod 52 drives the feed lifting tooth crank 53 to swing through the feed lifting tooth connecting plate 58, the feed lifting tooth shaft 20 is further driven to swing along with the feed lifting tooth crank 53, and the feed lifting tooth shaft 20 drives the feed lifting tooth frame 30 and the feed feeding tooth 40 to reciprocate up and down through the second feed lifting tooth driving component. Because the transmission efficiency of the composite four-bar mechanism is kept unchanged, the swing amplitude of the main shaft 10 driving the feed lifting tooth shaft 20 to swing is also unchanged, and the feed lifting tooth height of the feed feeding tooth 40 is also constant and is kept unchanged. When the lifting tooth height needs to be adjusted, the adjusting operation part 120 acts on the second adjusting connecting rod 81 through the adjusting driving component to change the position angle of the second adjusting connecting rod 81, so that the transmission efficiency of the compound four-bar mechanism is changed, the lifting tooth eccentric wheel 51 drives the lifting tooth crank 53 and the lifting tooth shaft 20 to swing through the lifting tooth connecting rod 52, namely the transmission efficiency between the lifting tooth eccentric wheel 51 and the lifting tooth shaft 20 is changed, the swing amplitude of the lifting tooth shaft 20 driven by the main shaft 10 is changed, and the lifting tooth height of the feeding tooth 40 is adjusted.

In the fourth embodiment of the sewing machine, the adjusting drive assembly has the following two preferred embodiments.

Embodiment one of the adjusting drive assembly

As shown in fig. 22 and 23, the adjustment driving assembly embodiment includes an adjustment lever 110 movably installed in the sewing machine housing, a second adjustment crank 82 having a third fixed swing fulcrum Q3, and a third adjustment crank 83 having a fourth fixed swing fulcrum Q4; the adjusting operation part 120 is connected to the rear end of the adjusting lever 110 to drive the adjusting lever 110 to move; the rear end face of the upper section of the second adjusting crank 82 is an abutting plane, the front end of the adjusting rod 110 is in abutting fit with the abutting plane of the second adjusting crank 82, the adjusting rod 110 is offset relative to a third fixed swing fulcrum Q3 of the second adjusting crank 82 in the vertical direction, and connection between the adjusting rod 110 and the second adjusting crank 82 is realized; the lower end of the second adjusting crank 82 is provided with a first notch, and is hinged with a second connecting pin parallel to the main shaft 10, and the second connecting pin is arranged in the first notch in a penetrating way; one end of the third adjusting crank 83 is provided with a crank connecting part positioned in the first notch, a fifth sliding groove is formed in the crank connecting part, and a second connecting pin at the lower end of the second adjusting crank 82 is positioned in the fifth sliding groove of the third adjusting crank 83 and is in sliding fit with the fifth sliding groove; the other end of the third adjusting crank 83 is hinged to the other end of the second adjusting link 81 via a third connecting pin extending left and right. The adjusting rod 110 is perpendicular to the main shaft 10 and extends forwards and backwards along the direction that the feeding tooth 40 transfers the sewing material forwards; the adjusting rod 110 is a screw rod which is in threaded connection with the sewing machine shell, so that the adjusting rod 110 can feed back and forth in the sewing machine shell; the adjustment operation part 120 is a knob fixed to the rear end of the adjustment lever 110. In order to ensure the reliability of the abutment between the adjusting rod 110 and the second adjusting crank 82, as shown in fig. 22 and 23, the first embodiment of the adjusting driving assembly further includes a second hanging plate 84 fixed to the second adjusting crank 82, and a second pressing spring 85, wherein the upper end of the second pressing spring 85 is connected to a fixed point in the sewing machine housing, and the lower end of the second pressing spring 85 is connected to the second hanging plate 84; the second hold-down spring 85 applies an urging force to the second adjustment crank 82 via the second hanging plate 84, so that the second adjustment crank 82 is always reliably abutted against the front end of the adjustment lever 110. The first embodiment of the adjusting driving assembly further comprises a second crank shaft 86 and a third crank shaft 87 fixed on the sewing machine shell, wherein the second crank shaft 86 and the third crank shaft 87 extend leftwards and rightwards; the second adjusting crank 82 is rotatably mounted on the second crank shaft 86, so that the second crank shaft 86 constitutes a third fixed swing fulcrum Q3 of the second adjusting crank 82; the third adjusting crank 83 is rotatably mounted on the third crank shaft 87, so that the third crank shaft 87 constitutes a fourth fixed swing fulcrum Q4 of the third adjusting crank 83.

When the sewing machine is working normally, the second adjusting crank 82 is kept at a fixed position under the limit of the cooperation of the second pressing spring 85 and the adjusting rod 110, and the position angle of the third adjusting crank 83 which is cooperated with the second adjusting crank 82 is also fixed. As shown in fig. 25, the cam eccentric 51, the cam connecting rod 52, the second adjusting connecting rod 81, the cam connecting plate 58 and the cam crank 53 form a fixed compound four-bar mechanism, the transmission efficiency of the compound four-bar mechanism is kept unchanged, so that the swing amplitude of the main shaft 10 for driving the cam shaft 20 to swing back and forth through the first cam transmission assembly is also kept unchanged, and the cam height of the feeding cam 40 is kept unchanged. When the lifting tooth height of the feeding tooth 40 is adjusted, the knob fixed at the rear end of the adjusting rod 110 is rotated, the knob drives the adjusting rod 110 to rotate together, and the adjusting rod 110 moves forwards or backwards relative to the sewing machine shell while rotating, so that the second adjusting crank 82 rotates around a third fixed swing fulcrum Q3; the second adjusting crank 82 drives a third adjusting crank 83 matched with the second adjusting crank to rotate around a fourth fixed swing fulcrum Q4, after the third adjusting crank 83 rotates for an angle, in a compound four-bar mechanism formed by the tooth lifting eccentric wheel 51, the tooth lifting connecting rod 52, the second adjusting connecting rod 81, the tooth lifting connecting plate 58 and the tooth lifting crank 53, the spatial position of a hinge point of the third adjusting crank 83 and the second adjusting connecting rod 81 is changed, the spatial position of the second adjusting connecting rod 81 is changed, the transmission efficiency of the compound four-bar mechanism is changed, the transmission efficiency from the main shaft 10 to the tooth lifting shaft 20 is further changed, and the tooth lifting height of the feeding tooth 40 can be freely adjusted within a certain range.

Second embodiment of the adjusting drive Assembly

The difference between the first adjusting drive assembly and the second adjusting drive assembly is that: 1. the connection mode between the adjusting rod 110 and the second adjusting crank 82 is different; 2. the third adjusting crank 83 has a different design. Specifically, in the second embodiment of the adjustment driving assembly, the connection between the adjustment rod 110 and the second adjustment crank 82 is as follows: as shown in fig. 24, the adjusting rod 110 is connected with the second adjusting crank 82 through the second connecting sleeve 88, the second connecting sleeve 88 is rotatably installed at the front end of the adjusting rod 110, but the second connecting sleeve 88 and the adjusting rod 110 cannot move relatively, the front end of the second connecting sleeve 88 is hinged with a fourth connecting pin parallel to the main shaft 10, the front end of the second connecting sleeve 88 has a second notch, the upper end portion of the second adjusting crank 82 is located in the second notch at the front end of the second connecting sleeve 88, the upper end portion of the second adjusting crank 82 is provided with a sixth sliding slot, and the fourth connecting pin hinged at the front end of the second connecting sleeve 88 is located in the sixth sliding slot at the upper end of the second adjusting crank 82 and is in sliding fit with the sixth sliding slot. The third adjusting crank 83 has the structural form: the third adjusting crank 83 in the first embodiment of the adjusting driving assembly is an open structure, and the adjusting crank and the second adjusting connecting rod 81 are arranged side by side in the left-right direction; the third adjusting crank 83 in the second embodiment of the adjusting driving assembly is of a closed structure and has two crank arms 831 arranged side by side left and right, the second adjusting connecting rod 81 is hinged to one crank arm 831 between the two crank arms 831, the other crank arm 831 is hinged to the lower end of the second adjusting crank 82 through a fifth connecting pin 89, and a seventh sliding slot in sliding fit with the fifth connecting pin 89 is formed in the crank arm 831.

Fifth embodiment of sewing machine: the feed lifting mechanism changes the transmission efficiency of the first feed lifting transmission assembly by changing the effective length of the feed lifting crank 53.

In the fifth embodiment of the sewing machine, as shown in fig. 26, the feed lifting height adjusting mechanism includes an adjusting drive assembly, an adjusting lever 110 mounted in the sewing machine housing to be movable forward and backward, and an adjusting operation portion 120 for driving the adjusting lever 110 to move. As shown in fig. 26 to 30, the first lifting tooth transmission assembly further comprises a first lifting tooth slider 59, and the lifting tooth eccentric wheel 51 is locked and fixed on the main shaft 10 through a screw; the upper end of the feed lifting connecting rod 52 is rotatably sleeved on the periphery of the feed lifting eccentric wheel 51; the lower end of the feed lifting connecting rod 52 is hinged with the first feed lifting sliding block 59 through a sixth connecting pin 510 extending left and right; a first feed lifting tooth sliding groove 531 is formed in the feed lifting tooth crank 53, and the first feed lifting tooth sliding block 59 is located in the first feed lifting tooth sliding groove 531 and is in sliding fit with the first feed lifting tooth sliding groove 531; preferably, the first tooth lifting slide block 59 is in surface contact with the groove wall of the first tooth lifting slide groove 531. The front end of the adjustment lever 110 acts on a transmission member in the first feed dog transmission assembly through an adjustment drive assembly. When the adjusting operation part 120 drives the adjusting rod 110 to move in the front-rear direction, the position of the first tooth lifting slider 59 in the first tooth lifting chute 531 in the extending direction of the first tooth lifting chute 531 is changed, so that the distance between the hinge point of the tooth lifting connecting rod 52 and the first tooth lifting slider 59 and the central axis of the tooth lifting shaft 20 is directly changed, that is, the effective length of the tooth lifting crank 53 is changed, the transmission efficiency of the composite crank-connecting rod slider mechanism formed by the tooth lifting connecting rod 52, the first tooth lifting slider 59 and the tooth lifting crank 53 is changed, that is, the swinging amplitude of the main shaft 10 driving the tooth lifting shaft 20 to swing through the first tooth lifting transmission assembly is changed, further, the amplitude of the tooth lifting shaft 20 driving the tooth frame 30 and the feeding tooth 40 to reciprocate up and down through the second tooth lifting transmission assembly is changed, and the automatic adjustment of the tooth lifting height is realized.

Preferably, as shown in fig. 26, the adjustment lever 110 is perpendicular to the main shaft 10 and extends forward and backward in a direction in which the feed dog 40 feeds the fabric forward. The adjusting lever 110 is in threaded fit with the sewing machine housing, and the adjusting operation part 120 is a knob fixed at the rear end of the adjusting lever 110; when the knob is rotated, the adjusting lever 110 is driven to rotate together, and the adjusting lever 110 moves forward or backward relative to the machine shell while rotating, thereby realizing that the adjusting lever 110 can be installed in the machine shell of the sewing machine in a way of moving forward and backward.

The preferred embodiment of the adjustment drive assembly is: as shown in fig. 28 to 30, the adjustment driving assembly includes a first supporting pin 99 fixed to the housing and extending left and right, a rotating crank 91 having a rear end rotatably mounted to the first supporting pin 99, an adjustment connecting plate 92, and a rotation driving unit connected between the rotating crank 91 and the adjustment lever 110; the first supporting pin 99 constitutes a fifth fixed swing fulcrum Q5 of the rotary crank 91; the front end of the rotating crank 91 is hinged with the front end of the adjusting connecting plate 92 through a fixing pin 93 extending left and right, the fixing pin 93 is fixed on the rotating crank 91, and the adjusting connecting plate 92 is hinged on the fixing pin 93; the rear end of the adjusting link plate 92, the lower end of the tooth lifting link 52 and the first tooth lifting slider 59 are coaxially hinged by the sixth link pin 510; when the adjustment lever 110 is moved in the front-rear direction, the adjustment lever 110 rotates the rotary crank 91 about the fifth fixed swing fulcrum Q5 by the rotation driving unit. Therefore, the front end of the adjustment lever 110 acts on the first tooth lifting slider 59 in the first tooth lifting transmission assembly through the adjustment drive assembly, and the first tooth lifting slider 59 constitutes a transmission member in the first tooth lifting transmission assembly.

When the sewing machine normally works, the position of the adjusting rod 110 relative to the sewing machine shell is kept unchanged, the rotating crank 91 is kept at a fixed position under the limiting action of the rotating driving unit and the adjusting rod 110, the rotating crank 91 keeps the position of the first feed lifting teeth slide block 59 in the first feed lifting teeth slide groove 531 unchanged through the adjusting connecting plate 92, so the distance between the hinge point of the feed lifting teeth connecting rod 52 and the first feed lifting teeth slide block 59 and the central axis of the feed lifting teeth shaft 20 is kept unchanged, namely the effective length of the feed lifting teeth crank 53 is kept unchanged. The main shaft 10 drives the cam 51 to rotate together, the lifting tooth crank 53 is driven to swing back and forth through the lifting tooth connecting rod 52 and the first lifting tooth slide block 59, the lifting tooth crank 53 and the lifting tooth shaft 20 swing back and forth together, and the tooth rack 30 and the feeding tooth 40 are driven to move back and forth up and down through the second lifting tooth transmission assembly. Because the distance between the hinge point of the feed lifting tooth connecting rod 52 and the first feed lifting tooth sliding block 59 and the central axis of the feed lifting tooth shaft 20 is kept constant, and the swing amplitude of the feed lifting tooth crank 53 is fixed, the swing amplitude of the main shaft 10 for driving the feed lifting tooth shaft 20 to swing back and forth through the first feed lifting tooth transmission component is also kept constant, so that the motion amplitude of the feed lifting tooth shaft 20 for driving the tooth frame 30 and the feed lifting tooth 40 to move back and forth up and down through the second feed lifting tooth transmission component is also kept constant, and the height of the feed lifting tooth 40 is also kept constant. When the height of the feed lifting teeth is adjusted, the knob is rotated to drive the adjusting rod 110 to rotate together, the adjusting rod 110 moves forwards or backwards along the self-axis direction through the thread fit between the adjusting rod 110 and the sewing machine shell, the rotating crank 91 rotates for an angle around the first supporting pin 99 through the rotation driving unit while the adjusting rod 110 moves, as shown in fig. 28 to 30 and fig. 33, the rotating crank 91 changes the angle, the adjusting connecting plate 92 acts on the first feed lifting teeth slider 59 to change the position of the first feed lifting teeth slider 59 in the first feed lifting teeth sliding groove 531 and simultaneously rotate the feed lifting teeth crank 53 for an angle, and the feed lifting teeth shaft 20 rotates for a corresponding angle along with the feed lifting teeth crank 53, the spatial position of the first lifting tooth slider 59 (including the angle of the first lifting tooth slider 59 and the position of the first lifting tooth slider 59 in the first lifting tooth chute 531 along the extending direction of the first lifting tooth chute 531) is changed, that is, the spatial position of the hinge point of the lifting tooth connecting rod 52 and the lifting tooth crank 53 in the first lifting tooth transmission assembly is changed, so that the effective length of the lifting tooth crank 53 is changed, the transmission efficiency from the main shaft 10 to the lifting tooth shaft 20 is changed, the swinging amplitude of the main shaft 10 driving the lifting tooth shaft 20 to swing through the first lifting tooth transmission assembly is changed, the amplitude of the lifting tooth shaft 20 driving the tooth rack 30 and the feeding tooth 40 to reciprocate up and down through the second lifting tooth transmission assembly is changed, and the automatic adjustment of the lifting tooth height is realized.

Further, the rotation driving unit connected between the adjustment lever 110 and the crank shaft 91 has two preferred embodiments as follows, and accordingly the adjustment driving assembly has two preferred embodiments.

First embodiment of the rotation driving unit, as shown in fig. 28 to 31, the rotation driving unit includes a third connection sleeve 94, a second support pin 910 fixed to the cabinet and extending left and right, and a rotation lever 95 rotatably mounted to the second support pin 910; the second support pin 910 constitutes a sixth fixed swing fulcrum Q6 of the turning lever 95; the third connecting sleeve 94 is rotatably mounted at the front end of the adjusting rod 110, but the third connecting sleeve 94 and the adjusting rod 110 cannot move relatively; a short pin parallel to the main shaft 10 is hinged in a fork opening part at the front end of the third connecting sleeve 94, two ends of the short pin are installed on the third connecting sleeve 94 through a snap spring, a fork opening part is arranged at the upper end of the rotating lever 95 and is also a sliding groove, and the short pin at the front end of the third connecting sleeve 94 is positioned in the sliding groove at the upper end of the rotating lever 95 and is in sliding fit with the sliding groove; the lower end of the turning lever 95 also has a fork, the fork at the lower end of the turning lever 95, the turning crank 91 and the adjusting link plate 92 are coaxially hinged by the fixing pin 93, and the fixing pin 93 is located in the fork at the lower end of the turning lever 95 and is in sliding fit with the fork. When the height of the feed dog 40 is adjusted, the adjusting rod 110 moves back and forth to drive the third connecting sleeve 94 to move back and forth together, so that the rotating lever 95 is driven to rotate around the second supporting pin 910, the rotating lever 95 drives the rotating crank 91 to rotate around the first supporting pin 99, and the adjustment of the height of the feed dog 40 is realized.

As shown in fig. 32, the second embodiment of the rotational driving unit includes a third support pin 911 fixed to the housing and extending left and right, a fourth adjustment crank 96 rotatably mounted on the third support pin 911, a third adjustment link 97, and a biasing tension spring 98; the third support pin 911 constitutes a seventh fixed swing fulcrum Q7 of the fourth adjustment crank 96; the fourth adjustment crank 96 has an abutment plane at the rear end, which abuts against the front end of the adjustment lever 110; the upper end of the third adjusting connecting rod 97 is hinged with the front end of the fourth adjusting crank 96 through a short pin extending left and right, and the lower end of the third adjusting connecting rod 97, the rotating crank 91 and the adjusting connecting plate 92 are coaxially hinged through the fixing pin 93; the upper end of the pre-tightening tension spring 98 is connected with a fixing screw fixed on the third adjusting connecting rod 97, the lower end of the pre-tightening tension spring 98 is connected with the bottom plate of the sewing machine, the pre-tightening tension spring 98 applies acting force to the third adjusting connecting rod 97, and the abutting plane at the rear end of the fourth adjusting crank 96 is always abutted to the front end of the adjusting rod 110 through the third adjusting connecting rod 97. When the height of the feed dog 40 is adjusted, the adjusting rod 110 moves back and forth to rotate the fourth adjusting crank 96 around the third supporting pin 911, and the fourth adjusting crank 96 drives the rotating crank 91 to rotate around the first supporting pin 99 through the third adjusting connecting rod 97, so that the height of the feed dog 40 is adjusted.

In the above five embodiments of the sewing machine, the second feed dog transmission assembly has the same structure, and the preferable structure is: as shown in fig. 5, the second lifting tooth transmission assembly includes a second lifting tooth slider 140 and a lifting tooth swing fork 150 fixedly locked on the lifting tooth shaft 20 by a screw, the second lifting tooth slider 140 is hinged with the dental articulator 30 by a pin extending left and right, a second lifting tooth sliding slot 151 is opened in the lifting tooth swing fork 150, and the second lifting tooth slider 140 is located in the second lifting tooth sliding slot 151 and is in sliding fit with the second lifting tooth sliding slot 151.

In summary, the first lifting teeth transmission assembly in the present application has adjustable transmission efficiency, and accordingly, the swing amplitude of the lifting teeth shaft 20 is also adjustable, so as to adjust the lifting teeth height of the feeding teeth 40, and the operation is very simple and convenient. Meanwhile, the adaptability of the sewing machine to sewing materials is enhanced by adjusting the height of the lifting teeth of the feeding teeth 40, the wrinkling phenomenon of the sewing materials can be improved by reducing the height of the lifting teeth of the feeding teeth 40 when thin materials are sewn, and the cloth feeding efficiency can be effectively improved by increasing the height of the lifting teeth of the feeding teeth 40 when thick materials are sewn and peduncle sewing is carried out, so that the cloth feeding is smoother. In particular, in the present application, when the feed dog 40 is adjusted in the feed dog height, the needle pitch of the sewing machine is kept unchanged, so that the sewing quality is not affected. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

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

Claims (1)

1. A feed lifting tooth height adjusting method for a sewing machine having a main shaft, a feed lifting tooth shaft parallel to the main shaft, a feed lifting tooth mounted on the feed lifting tooth shaft, a first feed lifting tooth transmission assembly connected between the main shaft and the feed lifting tooth shaft, and a second feed lifting tooth transmission assembly connected between the feed lifting tooth shaft and the feed lifting tooth shaft, the feed lifting tooth height adjusting method comprising the steps of:

1) The sewing machine is provided with a feed lifting tooth height adjusting mechanism, and the feed lifting tooth height adjusting mechanism acts on a first feed lifting tooth transmission assembly; the first feed lifting transmission assembly and the feed lifting height adjusting mechanism are matched in a structure that:

the first feed lifting tooth transmission assembly comprises a feed lifting tooth eccentric wheel, a feed lifting tooth connecting rod and a feed lifting tooth crank fixed on a feed lifting tooth shaft, the feed lifting tooth eccentric wheel is connected with the main shaft, two ends of the feed lifting tooth connecting rod are respectively connected with the feed lifting tooth eccentric wheel and the feed lifting tooth crank, the feed lifting tooth eccentric wheel is sleeved on the main shaft, the feed lifting tooth height adjusting mechanism is a feed lifting tooth eccentric adjusting assembly, and the feed lifting tooth eccentric adjusting assembly is connected with the main shaft and the feed lifting tooth eccentric wheel and is used for changing feed lifting tooth eccentric amount between a matching center of the feed lifting tooth eccentric wheel and the feed lifting tooth connecting rod and a rotation center of the main shaft; the tooth lifting eccentric adjusting assembly comprises a ratchet wheel, an adjusting sliding piece with a pawl part, an adjusting eccentric wheel, an adjusting slide block, a fixed slide block and a tooth lifting adjusting button, wherein the ratchet wheel and the fixed slide block are fixedly sleeved on the main shaft, the adjusting eccentric wheel is provided with a first sliding groove in sliding fit with the adjusting sliding piece and a first eccentric part extending away from the adjusting sliding piece, the tooth lifting eccentric wheel is provided with a second sliding groove in sliding fit with the fixed slide block and a second eccentric part extending away from the fixed slide block, the main shaft, the first eccentric part, the adjusting slide block, the second eccentric part and a tooth lifting connecting rod are sequentially sleeved from inside to outside along the radial direction of the main shaft, a long strip groove in the same direction as the extending direction of the first sliding groove is formed in the adjusting sliding piece, a first matching plane is arranged on the outer peripheral surface of the adjusting slide block, and a second matching plane matched with the first matching plane is arranged on the inner peripheral surface of the second eccentric part; when the tooth lifting adjusting button does not act on the adjusting slide piece, a pawl part on the adjusting slide piece is meshed with a ratchet on the ratchet wheel; when the tooth lifting adjusting button acts on the adjusting sliding piece, the adjusting sliding piece slides along the first sliding groove, so that a pawl part on the adjusting sliding piece is separated from a ratchet on the ratchet wheel, and then the main shaft is rotated to change the tooth lifting eccentric amount (L);

or the first lifting tooth transmission assembly comprises a lifting tooth eccentric wheel, a lifting tooth connecting rod, a lifting tooth crank fixed on a lifting tooth shaft and a lifting tooth connecting plate, the lifting tooth eccentric wheel is fixed on the main shaft, one end of the lifting tooth connecting rod is rotatably sleeved on the periphery of the lifting tooth eccentric wheel, the lifting tooth height adjusting mechanism comprises a second adjusting connecting rod, an adjusting driving assembly and an adjusting operation part, the other end of the lifting tooth connecting rod, one end of the lifting tooth connecting plate and one end of the second adjusting connecting rod are coaxially hinged through a pin, the other end of the lifting tooth connecting plate is hinged with the lifting tooth crank, and the adjusting operation part acts on the second adjusting connecting rod through the adjusting driving assembly and is used for changing the position of the second adjusting connecting rod; the adjusting driving component comprises an adjusting rod movably arranged in the sewing machine shell, a second adjusting crank with a third fixed swing fulcrum and a third adjusting crank with a fourth fixed swing fulcrum; the adjusting operation part is connected with the rear end of the adjusting rod and drives the adjusting rod to move; the front end of the adjusting rod is connected with the upper end of a second adjusting crank through a second connecting sleeve, the second connecting sleeve is rotatably arranged at the front end of the adjusting rod, but the second connecting sleeve and the adjusting rod cannot move relatively, the front end of the second connecting sleeve is hinged with a fourth connecting pin parallel to the main shaft, the front end of the second connecting sleeve is provided with a second notch, the upper end part of the second adjusting crank is positioned in the second notch at the front end of the second connecting sleeve, the upper end part of the second adjusting crank is provided with a sixth sliding chute, and the fourth connecting pin is positioned in the sixth sliding chute at the upper end of the second adjusting crank and is in sliding fit with the sixth sliding chute; the lower end of the second adjusting crank is connected with one end of a third adjusting crank; the other end of the third adjusting crank is hinged with the other end of the second adjusting connecting rod;

or the first feed lifting tooth transmission assembly comprises a feed lifting tooth eccentric wheel, a feed lifting tooth connecting rod, a feed lifting tooth crank fixed on a feed lifting tooth shaft and a first feed lifting tooth slide block, the feed lifting tooth eccentric wheel is fixed on the main shaft, one end of the feed lifting tooth connecting rod is rotatably sleeved on the periphery of the feed lifting tooth eccentric wheel, the feed lifting tooth height adjusting mechanism comprises an adjusting driving assembly, an adjusting rod movably arranged in the sewing machine shell and an adjusting operation part for driving the adjusting rod to move, the other end of the feed lifting tooth connecting rod is hinged with the first feed lifting tooth slide block, a first feed lifting tooth slide groove is formed in the feed lifting tooth crank, the first feed lifting tooth slide block is positioned in the first feed lifting tooth slide groove and is in sliding fit with the first feed lifting tooth slide groove, the first feed lifting tooth slide block is in surface contact with the groove wall of the first feed lifting tooth slide groove, and the adjusting driving assembly acts on the first feed lifting tooth slide block and is used for changing the position of the first feed lifting tooth slide block in the first feed lifting tooth slide groove in the extending direction; the adjusting driving assembly comprises a first supporting pin fixed on the sewing machine shell, a rotating crank with the rear end rotatably arranged on the first supporting pin, an adjusting connecting plate and a rotating driving unit connected between the rotating crank and the adjusting rod; the front end of the rotating crank is hinged with the front end of the adjusting connecting plate through a fixing pin extending left and right, the fixing pin is fixed on the rotating crank, and the adjusting connecting plate is hinged on the fixing pin; the rear end of the adjusting connecting plate, the lower end of the tooth lifting connecting rod and the first tooth lifting sliding block are coaxially hinged through a sixth connecting pin;

2) When the height of the lifting tooth needs to be adjusted, the lifting tooth height adjusting mechanism acts: the feed lifting device comprises a feed lifting tooth eccentric adjusting component, an adjusting operation part, a feed lifting tooth crank and a feed lifting tooth eccentric adjusting component, wherein the feed lifting tooth eccentric adjusting component changes feed lifting tooth eccentric amount between a matching center of a feed lifting tooth eccentric wheel and a feed lifting tooth connecting rod and a rotation center of a main shaft, or the adjusting operation part changes the position of a second adjusting connecting rod through adjusting a driving component to change transmission efficiency between the feed lifting tooth connecting rod and the feed lifting tooth crank, or the adjusting operation part changes the position of a first feed lifting tooth sliding block in a first feed lifting tooth sliding groove in the extending direction of the first feed lifting tooth sliding groove through adjusting a rod and the adjusting driving component to change the effective length of the feed lifting tooth crank, and the effective length of the feed lifting tooth crank is the distance between the connecting center of the feed lifting tooth connecting rod and the feed lifting tooth crank and the rotation center of the feed lifting tooth shaft.

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