CN112626730B - Sewing machine - Google Patents

Abstract

The invention provides a sewing machine, which comprises a main shaft, a tooth rack, feeding teeth arranged on the tooth rack, a feeding mechanism connected between the main shaft and one end of the tooth rack, a tooth lifting 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 driving cam driven to rotate by the driving source, a first transmission clutch mechanism and a second transmission clutch mechanism, wherein the feeding mechanism comprises a needle pitch seat with a first fixed swing fulcrum, the first transmission clutch mechanism acts between the driving cam and the needle pitch seat, and the second transmission clutch mechanism acts between the driving cam, a presser foot lifting transmission part in the presser foot lifting mechanism and a tooth lifting transmission part in the tooth lifting mechanism. This application adopts a driving source can control sewing machine's accent needle pitch respectively, lift the presser foot and pay-off tooth automatic decline these three functions when the blowing, and the regulation of needle pitch has still realized sewing machine's positive seam, backstitch and encryption seam simultaneously, reduces cost by a wide margin, and the space that occupies is littleer.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine.

Background

Sewing machines are of the flat-bed, over-lock, flat-bed or the like type, which use one or more sewing threads to form one or more stitches in the material to be sewn, so as to interweave or sew up one or more layers of material to be sewn. At present, an automatic backstitch mechanism, an automatic seam-thickening mechanism and an automatic presser foot lifting mechanism are arranged in a computer lockstitch sewing machine, and all the mechanisms are driven by electromagnets to realize the function of automatic control. However, the existing sewing machine has the following defects due to the adoption of electromagnet drive: 1. when the electromagnet drives the automatic backstitch mechanism, the regulator is required to swing to impact the stud so as to change the needle pitch, but noise is generated when the regulator and the stud impact, so that the use experience of a user is influenced; 2. the automatic seam-sealing mechanism needs an independent electromagnet, and continuous actions such as backstitch, trimming and the like are caused, so that the power supply is insufficient, and the action effect is influenced; 3. after the automatic presser foot lifting mechanism is driven by the electromagnet, the sound of the automatic presser foot lifting mechanism is loud, the customer experience is influenced, and the size of the electromagnet is not large due to space limitation of the existing built-in automatic presser foot lifting mechanism, so that the attraction of the electromagnet is insufficient, the use effect is influenced, and the service life of the electromagnet is also shortened.

Furthermore, in order to solve some defects caused by adopting an electromagnet, some sewing machines adopting a stepping motor to adjust the needle pitch and adopting a stepping motor to lift the presser foot are provided in the market at present, one stepping motor is adopted to control the swing seat to swing through one set of transmission mechanism to realize the needle pitch adjustment, the other stepping motor is adopted to drive the presser foot to lift through the other set of transmission mechanism, and therefore two stepping motors and corresponding control devices are arranged in one sewing machine, so that the cost is higher, the occupied space is larger, the heating is larger, and the technology is difficult to popularize in a large amount.

Further, the chinese patent application No. 201510515041.9 discloses a lockstitch sewing machine, which uses a stepping motor to realize two functions of needle pitch adjustment and automatic presser foot lifting, and has a cam driven by the stepping motor to rotate reciprocally, a stepping pressure lifting crank acting on a pressure lever, and a needle pitch adjustment crank acting on a feed shaft, and the cam has a stepping pressure lifting convex part for pushing the stepping pressure lifting crank and a needle pitch adjustment convex part for pushing the needle pitch adjustment crank. Therefore, the cam arranged in the flat sewing machine is provided with the two functional convex parts which are arranged along the axial direction of the cam in a staggered mode, the processing difficulty is high, particularly, a needle pitch adjusting mechanism is prone to causing inaccurate needle pitch adjustment due to the processing deviation and the installation precision deviation of the cam, the cam surface transmission is prone to abrasion compared with the conventional pin hole matching, and the needle pitch deviation can be caused.

Furthermore, the needle and the feeding tooth in the existing flat sewing machine are driven by the main shaft, and the needle and the feeding tooth are in synchronous linkage. Before sewing, in order to ensure that sewing materials are normally placed below a presser foot and on a needle plate, a machine needle and the presser foot in a flat sewing machine are required to be positioned above the needle plate, and the machine needle is driven to move by an operator through rotating a hand wheel fixed at the end part of a main shaft to enable the machine needle to move to the highest point; when the machine needle is located above the needle plate and moves to the highest point (namely, an upper needle stop position), due to the synchronous linkage relation between the machine needle and the feeding teeth, the feeding teeth also upwards emerge from tooth grooves of the needle plate, namely, one part of the feeding teeth upwards exposes out of the needle plate, at the moment, the feeding teeth can block the sewing materials from being put in, the sewing materials cannot be flatly put on the needle plate, particularly, the elastic thin materials, the sewing quality is further influenced, and the sewing experience is greatly reduced.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a sewing machine in which the needle pitch adjustment, the presser foot lifting, and the feed dog are driven to descend by the same driving source.

In order to achieve the above purpose, the invention provides a sewing machine, which comprises a main shaft, a tooth rack, feeding teeth arranged on the tooth rack, a feeding mechanism connected between the main shaft and one end of the tooth rack, a tooth lifting 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 driving cam driven to rotate by the driving source, a first transmission clutch mechanism and a second transmission clutch mechanism, wherein the feeding mechanism comprises a needle pitch seat with a first fixed swing fulcrum;

when the first transmission clutch mechanism enables power transmission between the driving cam and the needle gauge seat, the second transmission clutch mechanism enables no power transmission to be carried out between the driving cam and the pressure lifting and pressing foot transmission part and between the driving cam and the tooth lifting transmission part; at the moment, the driving source drives the driving cam to rotate, and the driving cam drives the needle pitch seat to rotate around the first fixed swing fulcrum through the first transmission clutch mechanism;

when the second transmission clutch mechanism enables power transmission to be realized between the driving cam and the presser foot lifting transmission part and between the driving cam and the tooth lifting transmission part, the first transmission clutch mechanism enables no power transmission to be realized between the driving cam and the needle pitch seat; at the moment, the driving source drives the driving cam to rotate, the driving cam drives the presser foot lifting mechanism to act through the second transmission clutch mechanism, so that the presser foot is lifted upwards, and the driving cam simultaneously drives the tooth lifting mechanism to act through the second transmission clutch mechanism, so that the tooth frame and the feeding tooth are lowered.

Further, the driving source is a motor, and the driving cam is fixed on a motor shaft of the motor.

Furthermore, the first transmission clutch mechanism comprises a first connecting rod, a second connecting rod, a stop plate fixed on the needle pitch seat, a fixed support fixed on the sewing machine shell and a first spring, wherein two ends of the first connecting rod are respectively hinged with the driving cam and the second connecting rod, the second connecting rod is hinged with the needle pitch seat, a limiting part capable of being abutted against the fixed support is arranged on the stop plate, two ends of the first spring are respectively connected with the stop plate and the fixed support, and the stop plate has a movement trend that the limiting part moves towards the direction close to the fixed support; when the first connecting rod and the second connecting rod are collinear, the first transmission clutch mechanism enables power transmission between the driving cam and the needle gauge seat, and the limiting part is not abutted with the fixed support; when the first connecting rod and the second connecting rod are not collinear, the first transmission clutch mechanism enables the driving cam and the needle gauge seat to have no power transmission, and the limiting part is abutted to the fixed support.

Further, a driving torsion spring is sleeved at the hinged position of the first connecting rod and the second connecting rod.

Further, the limiting part is located above the fixed support.

Further, the end face, facing the limiting portion, of the fixed support is fixedly provided with a limiting damping block, the limiting portion is provided with a contact surface facing the fixed support, and the contact surface is a flat plane and can be abutted against the limiting damping block.

Further, the feeding mechanism comprises a feeding shaft parallel to the main shaft, a first feeding transmission unit connected between the main shaft and the feeding shaft, and a second feeding transmission unit connected between the feeding shaft and the tooth rack; the first feeding transmission unit comprises a feeding eccentric wheel, a feeding connecting rod, a first swinging plate, a second swinging plate, a feeding crank and a needle distance seat, wherein the feeding eccentric wheel, the feeding connecting rod, the first swinging plate and the second swinging plate are fixed on a main shaft, the feeding crank and the needle distance seat are fixed on a feeding shaft, one end of the feeding connecting rod is rotatably installed on the periphery of the feeding eccentric wheel, the other end of the feeding connecting rod, one end of the first swinging plate and one end of the second swinging plate are coaxially hinged, the other end of the first swinging plate is hinged to the needle distance seat, and the other end of the second swinging plate is hinged to the feeding crank.

Further, the second transmission clutch mechanism comprises a drive plate with a second fixed swing fulcrum, a roller rotatably mounted at one end of the drive plate, a pressure lifting and pressing pin driving connecting rod and a lower driving supply connecting rod, the other end of the drive plate, one end of the pressure lifting and pressing pin driving connecting rod and one end of the lower driving supply connecting rod are coaxially hinged, the other end of the pressure lifting and pressing pin driving connecting rod is connected with the pressure lifting and pressing pin transmission part, the other end of the lower driving supply connecting rod is connected with the tooth lifting and pressing pin transmission part, and a section of variable-diameter driving surface is arranged on the outer peripheral surface of the driving cam; when the roller is in contact fit with a variable-diameter driving surface on the driving cam, the second transmission clutch mechanism enables power transmission to be available between the driving cam and the pressure lifting pin transmission part and between the driving cam and the tooth lifting transmission part; when the roller is not in contact fit with the variable-diameter driving surface on the driving cam, the second transmission clutch mechanism enables no power transmission to be carried out between the driving cam and the pressure lifting and pressing foot transmission part and between the driving cam and the tooth lifting and pressing tooth transmission part.

Furthermore, the peripheral surface of the driving cam is provided with a groove part, and the groove part is arranged adjacent to the reducing driving surface; when the roller is not in contact fit with the variable-diameter driving surface on the driving cam, the roller is positioned in the groove part and is not in contact with the driving cam.

Furthermore, the lower driving connecting rod and the tooth lifting transmission part are hinged through a first axial screw parallel to the main shaft, a first sliding groove extending up and down is formed in the lower end of the lower driving connecting rod, and the first axial screw penetrates through the first sliding groove and can be abutted against the upper end and the lower end of the first sliding groove.

Further, the tooth lifting mechanism 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 first feed lifting tooth connecting rod, a second feed lifting tooth connecting rod and a feed lifting tooth crank fixed on the feed lifting tooth shaft, one end of the first feed lifting tooth connecting rod is rotatably arranged on the periphery of the feed lifting tooth eccentric wheel, the other end of the first feed lifting tooth connecting rod, the second feed lifting tooth connecting rod and the feed lifting tooth crank are coaxially hinged, the second feed lifting tooth connecting rod is further hinged with the first feed lifting tooth connecting rod, and the second feed lifting tooth connecting rod further forms the feed lifting tooth transmission part.

Furthermore, the first feed lifting tooth connecting rod, the second feed lifting tooth connecting rod and the feed lifting tooth crank are hinged through a second axial screw parallel to the main shaft, a second sliding groove extending up and down is formed in the lower end of the first feed lifting tooth connecting rod, and the second axial screw penetrates through the second sliding groove; the first tooth lifting connecting rod and the second tooth lifting connecting rod are hinged through a third axial screw parallel to the main shaft, a third sliding groove extending horizontally is formed in the second tooth lifting connecting rod, and the third axial screw penetrates through the third sliding groove.

Further, the second tooth lifting connecting rod is concave and comprises a rod body portion extending up and down, an upper rod arm portion extending horizontally from the upper end of the rod body portion, and a lower rod arm portion extending horizontally from the lower end of the rod body portion, the second axial screw penetrates through the joint of the rod body portion and the lower rod arm portion, and the third sliding groove is formed in the upper end of the rod body portion and faces away from one side of the upper rod arm portion.

Furthermore, the first lifting tooth transmission unit further comprises a second spring, and two ends of the second spring are respectively connected with the first lifting tooth connecting rod and the second lifting tooth connecting rod, so that the third axial screw has a movement trend of moving towards the bottom of the third sliding groove.

Further, the presser foot lifting mechanism is provided with a right lever with a third fixed swing fulcrum, a presser foot lifting pull rod, a left lever with a fourth fixed swing fulcrum, a presser foot lifting plate, a pressure lever guide frame and a pressure lever extending up and down, the right lever forms the presser foot lifting transmission component, the other end of 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, the presser foot lifting plate is provided with a lifting hook part, the pressure lever guide frame is provided with a connecting protrusion part which is clamped with the lifting hook part, the pressure lever guide frame is fixed at the upper end of the pressure lever, and the presser foot is installed at the lower end of the pressure lever.

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

this application adopts a driving source can control sewing machine's accent needle pitch respectively, lift the presser foot and pay-off tooth automatic decline these three functions when the blowing, and the regulation of needle pitch has still realized sewing machine's positive seam, backstitch and encrypted seam simultaneously, adopts a driving source control sewing machine's one or two functions for prior art, and this application can reduce cost by a wide margin, and the structure is compacter, and the space that occupies is littleer, is favorable to the popularization and application of technique.

Drawings

Fig. 1 is a schematic view of a sewing machine according to the present application.

Fig. 2 is a schematic structural diagram of fig. 1 at another view angle, and the cabinet and the driving source in fig. 1 are omitted.

Fig. 3 is a schematic structural diagram of fig. 1 from a further view angle, and the chassis in fig. 1 is omitted.

Fig. 4 is a schematic view of the connection between the drive cam, the first drive clutch mechanism, and the needle bed in the present application.

Fig. 5 is a schematic view of the connection between the drive cam, the second transmission clutch mechanism, and the second feed dog link according to the present application.

Fig. 6 is a schematic structural diagram of a first tooth lifting transmission unit in the present application.

Fig. 7 is a schematic structural diagram of a first tooth lifting link in the present application.

Fig. 8 is a schematic structural view of a second tooth lifting link in the present application.

FIG. 9 is a view showing the state of the sewing machine of the present application during stitch length adjustment.

Fig. 10 is a state diagram of the sewing machine in the present application when the presser foot is lifted.

FIG. 11 is a view showing the state of the sewing machine in the present application when the sewing machine is feeding and discharging the cloth.

Description of the element reference numerals

10 spindle

20 dental articulator

30 feeding tooth

40 feeding mechanism

41 gauge needle seat

42 feeding shaft

43 feeding eccentric wheel

44 feeding connecting rod

45 first swinging plate

46 second swinging plate

47 feeding crank

48 first supporting pin

49 dental articulator base

50 lifting tooth mechanism

51 lifting tooth shaft

52 eccentric cam of lifting tooth

53 first lifting tooth connecting rod

531 second chute

54 second feed lifting connecting rod

541 stick body part

542 upper lever arm

543 lower lever arm part

544 third chute

55 lifting rock shaft crank

56 second spring

57 lifting fork

58 lifting tooth slide block

59 spring hanging pin

60 lift presser foot mechanism

61 Right lever

62 lifting presser foot pull rod

63 left lever

64 Lift presser foot lifting plate

65 pressure bar guide frame

66 pressure lever

70 first transmission clutch mechanism

71 first link

72 second connecting rod

73 stop plate

731 limiting part

74 fixed support

75 first spring

76 drive torsion spring

77 spacing shock-absorbing block

80 second transmission clutch mechanism

81 drive plate

82 rollers

83 lifting presser foot driving connecting rod

84 lower driving connecting rod

841 first sliding groove

85 second support pin

90 presser foot

110 driving source

120 drive cam

121 reducing driving surface

122 groove part

130 casing

140 needle plate

150 first axial position screw

160 second axial screw

170 third axial position screw

Detailed Description

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

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

The present application provides a sewing machine, as shown in fig. 1 to 3, including a housing 130, a main shaft 10 rotatably installed in the housing 130, and a main motor installed in the housing 130 and driving the main shaft 10 to rotate. For convenience of description, the axial direction of the main shaft 10 is defined as a left-right direction, the direction of the main shaft 10 toward the head of the sewing machine is a left direction, i.e., the direction of the main shaft 10 toward the left side of the paper surface in the view of fig. 3, and the direction of the main shaft 10 toward the tail of the sewing machine is a right direction, i.e., the direction of the main shaft 10 toward the right side of the paper surface in the view of fig. 3; the moving direction of the sewing material when the sewing machine is used for sewing is defined as a front direction.

As shown in fig. 1 to 3, the sewing machine further comprises a thread frame 20, a feeding thread 30 fixedly installed on the thread frame 20, a feeding mechanism 40 connected between the main shaft 10 and the front end of the thread frame 20, a thread lifting mechanism 50 connected between the main shaft 10 and the rear end of the thread frame 20, a presser foot 90, a presser foot lifting mechanism 60 connected with the presser foot 90, a driving source 110, a driving cam 120 driven to rotate by the driving source 110, a first transmission clutch mechanism 70 and a second transmission clutch mechanism 80, wherein the feeding mechanism 40 comprises a needle pitch seat 41 with a first fixed swing fulcrum O1; the first transmission clutch mechanism 70 acts between the driving cam 120 and the needle pitch seat 41 and is used for realizing unpowered transmission between the driving cam 120 and the needle pitch seat 41; the second transmission clutch mechanism 80 acts between the drive cam 120, a lifter foot transmission member in the lifter foot mechanism 60, and a lifter tooth transmission member in the lifter tooth mechanism 50, and is used for realizing unpowered transmission between the drive cam 120 and the lifter foot transmission member and unpowered transmission between the drive cam 120 and the lifter tooth transmission member.

When the sewing machine is used for normal sewing, the driving source 110 does not act, the driving cam 120 is in a static state, the main motor drives the main shaft 10 to rotate, the main shaft 10 drives the tooth frame 20 and the feeding teeth 30 to reciprocate back and forth through the feeding mechanism 40, the main shaft 10 drives the tooth frame 20 and the feeding teeth 30 to reciprocate up and down through the tooth lifting mechanism 50, therefore, the feeding teeth 30 do periodic compound motion of back and forth reciprocating motion and up and down reciprocating motion, and the motion trail of the feeding teeth 30 is elliptical. As shown in fig. 3, a needle plate 140 of the sewing machine is provided with a plurality of tooth grooves extending back and forth, the feed dog 30 can protrude upwards from the tooth grooves and be exposed on the upper surface of the needle plate 140, and the tooth frame 20 is positioned below the needle plate 140. When the sewing machine needs to adjust the needle pitch, the first transmission clutch mechanism 70 enables the power transmission between the driving cam 120 and the needle pitch seat 41, but the second transmission clutch mechanism 80 enables the power transmission not to be carried between the driving cam 120 and the presser foot lifting transmission part and between the driving cam 120 and the tooth lifting transmission part; at this time, the driving source 110 drives the driving cam 120 to rotate, the driving cam 120 drives the needle pitch base 41 to rotate around the first fixed swing fulcrum O1 through the first transmission clutch mechanism 70, so that the motion amplitude of the main shaft 10 driving the tooth rack 20 and the feeding tooth 30 to reciprocate back and forth through the feeding mechanism 40 can be changed, and the needle pitch adjustment is realized; and the functions of front sewing, back sewing and seam encryption of the sewing machine are realized simultaneously through the change of the stitch length. When the sewing machine needs to lift the presser foot, the second transmission clutch mechanism 80 enables the power transmission between the driving cam 120 and the presser foot lifting transmission part and between the driving cam 120 and the tooth lifting transmission part, but the first transmission clutch mechanism 70 enables the power-free transmission between the driving cam 120 and the needle pitch seat 41; at this time, the driving source 110 drives the driving cam 120 to rotate, the driving cam 120 drives the presser foot lifting mechanism 60 to act through the second transmission clutch mechanism 80, so that the presser foot 90 is lifted upwards, the driving cam 120 drives the tooth lifting mechanism 50 to act through the second transmission clutch mechanism 80, so that the tooth frame 20 and the feeding teeth 30 are lowered, the feeding teeth 30 automatically move downwards to the lower part of the upper surface of the needle plate 140 when the presser foot is lifted, the lower feeding and discharging action is executed, and the sewing material can be conveniently placed between the needle plate 140 and the presser foot 90 or the sewing material between the needle plate 140 and the presser foot 90 can be conveniently taken away.

Therefore, the sewing machine adopts the driving source 110 to respectively control three functions of adjusting the needle pitch, lifting the presser foot and automatically descending the feeding tooth 30 (namely, supplying and discharging materials downwards) when discharging, and the needle pitch adjustment simultaneously realizes the switching among the front sewing, the back sewing and the encrypted sewing of the sewing machine. In particular, the first transmission clutch mechanism 70 and the second transmission clutch mechanism 80 realize that the sewing machine does not perform the action of automatically descending the presser foot lifting and the feeding tooth 30 when the driving source 110 controls the sewing machine to adjust the needle pitch, and the sewing machine does not perform the action of adjusting the needle pitch when the driving source 110 controls the sewing machine to automatically descend the presser foot lifting and the feeding tooth 30 (namely, when the driving source 110 controls the sewing machine to automatically descend and then reset, the needle pitch of the sewing machine is not changed). Compared with the prior art, the sewing machine control system has the advantages that one or two functions of the sewing machine controlled by one driving source 110 are adopted, the cost can be greatly reduced, the structure is more compact, the occupied space is smaller, and the popularization and the application of the technology are facilitated.

Preferably, as shown in fig. 1 and 3, the driving source 110 is a motor and is fixedly installed on the housing 130, and a stepping motor is selected in this embodiment; the driving cam 120 is fixed on a motor shaft of the motor, and the motor directly drives the driving cam 120 to rotate.

The preferable structure of the feeding mechanism 40 is: as shown in fig. 2 to 4, the feeding mechanism 40 includes a feeding shaft 42 parallel to the main shaft 10, a first feeding transmission unit connected between the main shaft 10 and the right end of the feeding shaft 42, and a second feeding transmission unit connected between the left end of the feeding shaft 42 and the front end of the feed rack 20, and the feeding shaft 42 is rotatably installed in the sewing machine housing 130. The first feeding transmission unit comprises a feeding eccentric wheel 43 fixed on the main shaft 10, a feeding connecting rod 44, a first swinging plate 45, a second swinging plate 46, a feeding crank 47 fixed at the right end of the feeding shaft 42 and a needle pitch seat 41, wherein the upper end of the feeding connecting rod 44 is rotatably installed on the periphery of the feeding eccentric wheel 43, the lower end of the feeding connecting rod 44, the rear end of the first swinging plate 45 and the rear end of the second swinging plate 46 are coaxially hinged through a shaft axis pin extending left and right, the front end of the first swinging plate 45 is hinged with the needle pitch seat 41 through a shaft axis pin extending left and right, and the front end of the second swinging plate 46 is hinged with the feeding crank 47 through a shaft axis pin extending left and right. The needle gage 41 is rotatably attached to first support pins 48 extending in the left and right directions, respectively, the first support pins 48 are fixed to the housing 130, the first support pins 48 constitute first fixed swing support points O1 of the needle gage 41, and the needle gage 41 is rotatable about the first support pins 48. The second feeding transmission unit includes a dental articulator holder 49 fixed to the left end of the feeding shaft 42, the dental articulator holder 49 being connected to the front end of the dental articulator 20. The main shaft 10 drives the feeding shaft 42 to swing through the first feeding transmission unit, the feeding shaft 42 drives the tooth frame 20 to reciprocate back and forth through the second feeding transmission unit, the position angle of the needle distance seat 41 in the first feeding transmission unit directly determines the transmission efficiency between the main shaft 10 and the feeding shaft 42, so that the swing amplitude of the main shaft 10 driving the feeding shaft 42 to swing can be changed by changing the position angle of the needle distance seat 41, the motion amplitude of the reciprocating motion of the tooth frame 20 and the feeding teeth 30 back and forth is changed, and the needle distance adjustment and the switching between the front sewing, the back sewing and the encryption sewing are realized.

The preferred structure of the first transmission clutch mechanism 70 is: as shown in fig. 2 and 4, the first transmission clutch mechanism 70 includes a first link 71, a second link 72, a stopper plate 73 fixed to the rear end of the needle gage holder 41, a fixed support 74 fixed to the sewing machine housing 130, and a first spring 75; the upper end of the first link 71 and the driving cam 120, the lower end of the first link 71 and the upper end of the second link 72, and the lower end of the second link 72 and the needle gage base 41 are hinged by axis pins extending in the left-right direction, respectively, and the hinge point of the second link 72 and the needle gage base 41 is located on the rear side of the first fixed swing fulcrum O1; a limiting part 731 is arranged at the upper end of the rear side of the stop plate 73, and the limiting part 731 is positioned above the rear section part of the fixed support 74 and can be abutted against the fixed support 74; the front end of the first spring 75 is connected with the front section of the fixed support 74, the rear end of the first spring 75 is connected with the lower end of the rear side of the stop plate 73, and the first spring 75 applies a downward oblique pulling force to the stop plate 73, so that the stop plate 73 keeps the tendency of rotating towards the pulling force direction of the first spring 75; therefore, the stopper plate 73 and the needle gage 41 have a tendency to rotate downward about the first support pin 48 under the tensile force of the first spring 75, that is, the stopper plate 73 and the needle gage 41 have a tendency that the stopper portion 731 of the stopper plate 73 rotates downward toward the fixed support 74.

In the first transmission clutch mechanism 70, when the first link 71 and the second link 72 are collinear, that is, when the hinge point of the driving cam 120 and the first link 71, the hinge point of the first link 71 and the second link 72, and the hinge point of the second link 72 and the needle gage base 41 are collinear, the first link 71 and the second link 72 are equivalent to one link, the first transmission clutch mechanism 70 enables power transmission between the driving cam 120 and the needle gage base 41, so as to realize the motion joint between the driving cam 120 and the needle gage base 41, that is, the motion joint between the driving source 110 and the needle gage base 41; the limiting part 731 and the fixed support 74 are not in contact with each other or not in contact with each other; at this time, when the driving source 110 rotates the driving cam 120, the driving cam 120 drives the needle gage holder 41 to rotate about the first fixed swing fulcrum O1 via the first link 71 and the second link 72, so that the position angle of the needle gage holder 41 can be changed. When the first link 71 and the second link 72 are not collinear, that is, the hinge point of the driving cam 120 and the first link 71, the hinge point of the first link 71 and the second link 72, and the hinge point of the second link 72 and the needle gage seat 41 are not collinear, the first transmission clutch mechanism 70 enables no power transmission between the driving cam 120 and the needle gage seat 41, so as to separate the movement between the driving cam 120 and the needle gage seat 41, that is, separate the movement between the driving source 110 and the needle gage seat 41; meanwhile, the limiting part 731 is in a state of abutting against the fixed support 74; at this time, when the driving source 110 rotates the driving cam 120, the driving cam 120 does not drive the needle gage holder 41 to rotate through the first link 71 and the second link 72, no matter how the driving cam 120 rotates, that is, the needle gage holder 41 remains stationary.

Further, when the limit portion 731 and the fixed support 74 change from the abutting and contacting state to the disengaging state, the sewing machine is located at the maximum positive stitch length of the positive stitch, that is, the sewing machine has the maximum positive stitch length at this time; in the needle pitch adjusting process of the sewing machine, three points of a hinge point of the driving cam 120 and the first connecting rod 71, a hinge point of the first connecting rod 71 and the second connecting rod 72 and a hinge point of the second connecting rod 72 and the needle pitch base 41 are always collinear, and power is always transmitted between the driving cam 120 and the needle pitch base 41; when the driving source 110 drives the driving cam 120 to rotate, the driving cam 120 drives the needle pitch seat 41 and the stop plate 73 to swing upwards through the first connecting rod 71 and the second connecting rod 72, so that the limiting part 731 is further away from the fixed support 74; therefore, the three points of the hinge point of the driving cam 120 and the first link 71, the hinge point of the first link 71 and the second link 72, and the hinge point of the second link 72 and the needle gage seat 41 are still collinear; in other words, the three points of the hinge point of the driving cam 120 and the first link 71, the hinge point of the first link 71 and the second link 72, and the hinge point of the second link 72 and the needle base 41 are always collinear within the needle range allowed by the sewing machine. When the sewing machine lifts the presser foot and feeds materials downwards, the driving source 110 drives the driving cam 120 to rotate, the driving cam 120 drives the needle pitch seat 41 and the stop plate 73 to swing downwards through the first connecting rod 71 and the second connecting rod 72, so that the limiting part 731 is close to the fixed support 74, the needle pitch value of the sewing machine is gradually increased, and the limiting part 731 is gradually close to the fixed support 74; after the limiting part 731 is abutted to the fixed support 74, the sewing machine crosses the maximum positive needle pitch along with the continuous rotation of the driving cam 120, and the three points of the hinge point of the driving cam 120 and the first connecting rod 71, the hinge point of the first connecting rod 71 and the second connecting rod 72 and the hinge point of the second connecting rod 72 and the needle pitch base 41 are changed from a state of three-point collinearity into a state of three-point non-collinearity, so that the first connecting rod 71 and the second connecting rod 72 are correspondingly changed from a collinearity state into an included angle state; after the presser foot lifting and feeding under are finished, the presser foot 90, the feeding teeth 30, the driving cam 120, the needle distance seat 41 and the stop plate 73 are reset, the limiting part 731 and the fixed support 74 are reset to be in a separated state from a contact state, the first connecting rod 71 and the second connecting rod 72 are reset to be in a collinear state from an included angle state, and the sewing machine restores the current needle distance before the presser foot lifting and feeding under are finished.

Preferably, as shown in fig. 2 and 4, the stopper plate 73 and the fixing bracket 74 are provided with a hook portion connected to the first spring 75. The hinged position of the first connecting rod 71 and the second connecting rod 72 is sleeved with a driving torsion spring 76, two ends of the driving torsion spring 76 are respectively connected with the first connecting rod 71 and the second connecting rod 72, the driving torsion spring 76 enables the first connecting rod 71 and the second connecting rod 72 to keep a non-collinear turning trend, and then when the presser foot is lifted and feeding is carried out, the first connecting rod 71 and the second connecting rod 72 are changed from a collinear state to an included angle state, and the turning direction is given. A limiting damping block 77 is fixed on the upper end surface of the fixed support 74 facing the limiting part 731, the lower end surface of the limiting part 731 is a contact surface facing the fixed support 74, and the contact surface is a flat surface and can be abutted against the limiting damping block 77; therefore, when the contact surface of the stopper portion 731 and the fixed holder 74 are changed from the disengaged state to the abutting state, the contact surface of the stopper portion 731 strikes against the stopper damper block 77, and the stopper damper block 77 performs a damping function and can reduce noise generated by the striking.

The preferred structure of the second transmission clutch mechanism 80 is: as shown in fig. 2 and 5, the second transmission clutch mechanism 80 includes a driving plate 81 having a second fixed swing fulcrum O2, a roller 82 rotatably mounted on the rear end of the driving plate 81, a pressure raising and pressing pin driving link 83, and a lower supply driving link 84, the front end of the driving plate 81, the lower end of the pressure raising and pressing pin driving link 83, and the upper end of the lower supply driving link 84 are coaxially hinged by a shaft pin extending forward and backward, the upper end of the pressure raising and pressing pin driving link 83 is connected to a pressure raising and pressing pin transmission member in the pressure raising and pressing pin mechanism 60, the lower end of the lower supply driving link 84 is connected to a tooth raising transmission member in the tooth raising mechanism 50, and the outer peripheral surface of the driving cam 120 has a variable diameter driving surface 121. In the normal sewing process of the sewing machine and the adjustment process of the sewing machine, the roller 82 is not in contact fit with the variable diameter driving surface 121 on the driving cam 120, at the moment, no power transmission exists between the roller 82 and the driving cam 120, so the second transmission clutch mechanism 80 enables no power transmission to exist between the driving cam 120 and the presser foot lifting transmission part and between the driving cam 120 and the tooth lifting transmission part, and the separation of the movement between the driving cam 120 and the presser foot lifting transmission part and between the driving cam 120 and the tooth lifting transmission part is realized, namely the separation of the movement between the driving source 110 and the presser foot lifting mechanism 60 and between the driving source 110 and the tooth lifting mechanism 50 is realized. When the sewing machine lifts the presser foot and supplies the material downwards, the roller 82 is in contact fit with the variable diameter driving surface 121 on the driving cam 120, at the moment, power transmission exists between the roller 82 and the driving cam 120, the driving cam 120 pushes the roller 82 through the variable diameter driving surface 121, the driving plate 81 rotates around a second fixed swing fulcrum O2 through the roller 82, the driving plate 81 drives the presser foot lifting transmission component to act through the presser foot lifting driving connecting rod 83, and the driving plate 81 simultaneously drives the tooth lifting transmission component to act through the lower driving connecting rod 84, so the second transmission clutch mechanism 80 enables power transmission to exist between the driving cam 120 and the presser foot lifting transmission component and between the driving cam 120 and the tooth lifting transmission component, and realizes the joint of the motion between the driving cam 120 and the presser foot lifting transmission component and between the driving cam 120 and the tooth lifting transmission component, namely realizes the joint of the motion between the driving source 110 and the presser foot lifting mechanism 60, And the engagement of movement between the drive source 110 and the feed-dog mechanism 50.

Preferably, the roller 82 and the driving cam 120 are realized in a mode of no power transmission when the roller 82 is in non-contact fit with the variable diameter driving surface 121 on the driving cam 120: first, as shown in fig. 5, the driving cam 120 has a groove portion 122 on its outer circumferential surface, and the groove portion 122 is disposed adjacent to the variable diameter driving surface 121; when the driving source 110 drives the driving cam 120 to rotate and the groove part 122 on the driving cam 120 is rotated to the lower part of the roller 82, the roller 82 is positioned in the groove part 122, but the roller 82 is not contacted with the outer peripheral surface of the driving cam 120 and is in a separated state, thereby realizing no power transmission between the roller 82 and the driving cam 120 when the roller 82 is not contacted and matched with the variable diameter driving surface 121 on the driving cam 120. In the second mode, an equal-diameter driving surface adjacent to the variable-diameter driving surface 121 is provided on the outer peripheral surface of the driving cam 120; when the driving source 110 drives the driving cam 120 to rotate, and the constant-diameter driving surface on the driving cam 120 rotates to the position below the roller 82, the roller 82 is in contact fit with the constant-diameter driving surface, so that no power transmission is realized between the roller 82 and the driving cam 120 when the roller 82 is not in contact fit with the variable-diameter driving surface 121 on the driving cam 120.

Further, as shown in fig. 5, the right end surface of the driving plate 81 is rotatably mounted to a second support pin 85 extending left and right, the second support pin 85 is fixed in the housing 130, the second support pin 85 constitutes a second fixed swing fulcrum O2 of the driving plate 81, and the driving plate 81 is rotatable about the second support pin 85. In addition, due to the difference between the stroke of lifting the presser foot and the stroke of feeding the material by supplying the material downwards, a section of idle stroke is required to be arranged between the driving connecting rod 84 for supplying the material downwards and the feed lifting tooth transmission component when the presser foot is lifted; based on this, as shown in fig. 5, the lower driving link 84 and the tooth lifting transmission member are hinged by a first axial screw 150 parallel to the main shaft 10, the lower end of the lower driving link 84 is provided with a first sliding slot 841 extending up and down, the first axial screw 150 is inserted into the first sliding slot 841 and is in sliding fit with the first sliding slot 841, and the first axial screw 150 can be abutted against the upper and lower ends of the first sliding slot 841. When the presser foot is not lifted, the first axial position is positioned at the lower end of the first chute 841; when the presser foot lifting is started, the driving plate 81 drives the presser foot lifting driving connecting rod 83 and the lower supply driving connecting rod 84 to move downwards, the presser foot lifting transmission part starts to act and starts to lift the presser foot, but the first chute 841 of the lower supply driving connecting rod 84 moves downwards relative to the first axial screw 150, so the lower supply driving connecting rod 84 cannot drive the tooth lifting transmission part to act; when the upper end of the first chute 841 abuts against the first axial screw 150, the lower feeding driving link 84 drives the feed lifting transmission component to move and start feeding and discharging.

The preferred structure of the tooth lifting mechanism 50 is: as shown in fig. 2 and 3, and fig. 5 and 6, the feed lifting mechanism 50 includes a feed lifting shaft 51 parallel to the main shaft 10, a first feed lifting transmission unit connected between the main shaft 10 and a right end of the feed lifting shaft 51, and a second feed lifting transmission unit connected between a left end of the feed lifting shaft 51 and a rear end of the feed lifting frame 20, and the feed lifting shaft 51 is rotatably installed in the sewing machine housing 130. The first feed dog transmission unit comprises a feed dog eccentric wheel 52 fixed on the main shaft 10, a first feed dog connecting rod 53, a second feed dog connecting rod 54 and a feed dog crank 55 fixed on a feed dog shaft 51, wherein the upper end of the first feed dog connecting rod 53 is rotatably mounted on the periphery of the feed dog eccentric wheel 52, the lower end of the first feed dog connecting rod 53, the lower end of the second feed dog connecting rod 54 and the feed dog crank 55 are coaxially hinged through a second axial screw 160 extending left and right, the upper end of the second feed dog connecting rod 54 is also hinged with the middle part of the first feed dog connecting rod 53 through a third axial screw 170 extending left and right, and the second feed dog connecting rod 54 also forms a feed dog transmission part and is connected with a second transmission clutch mechanism 80, namely, the lower end of the lower supply driving connecting rod 84 is hinged with the second feed dog connecting rod 54 through the first axial screw 150. The second feed lifting transmission unit comprises a feed lifting fork 57 fixed at the left end of the feed lifting shaft 51, a feed lifting chute formed in the feed lifting fork 57, and a feed lifting slider 58 in sliding fit with the feed lifting chute, wherein the feed lifting slider 58 is hinged with the rear end of the dental articulator 20 by a shaft pin extending left and right.

Further, as shown in fig. 6 to 8, the lower end of the first lifting tooth connecting rod 53 is provided with a second sliding groove 531 extending up and down, and a second axial screw 160 coaxially hinged with the first lifting tooth connecting rod 53, the second lifting tooth connecting rod 54 and the lifting tooth crank 55 is inserted into the second sliding groove 531 and is in sliding fit with the same; a third chute 544 extending horizontally is formed in the second lifting tooth connecting rod 54, and a third axial screw 170 for hinging the first lifting tooth connecting rod 53 and the second lifting tooth connecting rod 54 is arranged in the third chute 544 in a penetrating manner, so that the first lifting tooth connecting rod 53 does not interfere with the movement of the second lifting tooth connecting rod 54 when the materials are supplied and discharged from the lower part. Preferably, the second tooth-lifting link 54 is concave, and includes a rod body 541 extending vertically, an upper rod arm 542 extending horizontally and forward from an upper end of the rod body 541, and a lower rod arm 543 extending horizontally and forward from a lower end of the rod body 541, the second axial screw 160 is inserted into a joint of the rod body 541 and the lower rod arm 543, the third chute 544 is opened at the upper end of the rod body 541 and faces away from the upper rod arm 542, and the third chute 544 is a U-shaped slot with a rearward opening. In addition, the first tooth lifting transmission unit further comprises a second spring 56, spring hanging pins 59 are fixed on the middle section of the first tooth lifting connecting rod 53 and the front end of an upper rod arm 542 in the second tooth lifting connecting rod 54, the rear end of the second spring 56 is connected with the spring hanging pin 59 on the first tooth lifting connecting rod 53, and the front end of the second spring 56 is connected with the spring hanging pin 59 on the upper rod arm 542 in the second tooth lifting connecting rod 54, so that the second spring 56 is connected between the first tooth lifting connecting rod 53 and the second tooth lifting connecting rod 54; under the tension of the second spring 56, the first lifting tooth link 53 and the third axial screw 170 have a tendency to move forward, thereby causing the third axial screw 170 to have a tendency to move forward toward the bottom of the third runner 544, holding the third axial screw 170 at the bottom of the third runner 544.

The preferable structure of the presser foot lifting mechanism 60 is: as shown in fig. 2, 3 and 10, the presser foot lifting mechanism 60 includes a right lever 61 having a third fixed pivot point O3, a presser foot lifting lever 62, a left lever 63 having a fourth fixed pivot point O4, a presser foot lifting plate 64, a presser bar guide 65, and a presser bar 66 extending vertically; wherein, the right lever 61 and the left lever 63 are both hinged to the cabinet 130 by means of axis pins extending forward and backward; the right lever 61 forms a pressure foot lifting transmission part and is connected with the second transmission clutch mechanism 80, namely, the upper end of the pressure foot lifting driving connecting rod 83 is hinged with the right end of the right lever 61; the left end of the right lever 61 is hinged with the right end of the pressure foot lifting pull rod 62, the left end of the pressure foot lifting pull rod 62 is hinged with the upper right of the left lever 63, the left lower end of the left lever 63 is hinged with the upper end of the pressure foot lifting plate 64, the pressure foot lifting plate 64 is provided with a lifting hook part, a connecting protruding part clamped with the lifting hook part is arranged on the pressure rod guide frame 65, the pressure rod guide frame 65 is fixed at the upper end of a pressure rod 66, the pressure foot 90 is installed at the lower end of the pressure rod 66, and the pressure foot 90 is positioned above the needle plate 140.

Further, in the sewing machine according to the present application, the feed eccentric 43 and the feed lifting eccentric 52 may be two eccentric wheels independent from each other, or may be one eccentric wheel, and when the feed eccentric 43 and the feed lifting eccentric 52 are one eccentric wheel, the eccentric wheel has a feed eccentric portion connected to the feed link 44 and a feed lifting eccentric portion connected to the first feed lifting link 53.

Taking the example of the recess portion 122 on the driving cam 120, the sewing machine with the above structure works according to the following principle:

the stitch length of the sewing machine has a negative value and a positive value, when the stitch length of the sewing machine is the negative value, the sewing machine is in a backstitch mode, and the smaller the stitch length value is, the larger the backstitch stitch length is; when the needle pitch of the sewing machine is 0 or close to 0, the sewing machine is in an encryption sewing mode; when the stitch length of the sewing machine is a positive value, the sewing machine is in a positive sewing mode, and the larger the stitch length value is, the larger the positive sewing stitch length is. When the sewing machine is located at the maximum stitch length of the front seam, the limit part 731 on the stop plate 73 is just separated from the limit shock-absorbing block 77 on the fixed support 74, and the two are not abutted. When the sewing machine is in the allowable needle distance range, the limit part 731 on the stop plate 73 and the limit shock-absorbing block 77 on the fixed support 74 are always in a disengaged state, and three points of a hinge point of the driving cam 120 and the first link 71, a hinge point of the first link 71 and the second link 72, and a hinge point of the second link 72 and the needle distance seat 41 are always collinear.

Fig. 9 to 11 show views in which the sewing machine happens to be located at the maximum gauge of the right stitch.

When the needle pitch of the sewing machine is adjusted, from the view angle shown in fig. 9, the driving source 110 drives the driving cam 120 to rotate anticlockwise, the groove part 122 on the driving cam 120 is positioned below the roller 82, so that the driving cam 120 is not contacted with and suspended in the air with the roller 82, the roller 82 and the driving plate 81 are kept still, no power transmission is carried between the driving cam 120 and the presser foot lifting transmission component and between the driving cam 120 and the tooth lifting transmission component, and the presser foot lifting mechanism 60 and the tooth lifting mechanism 50 do not act; meanwhile, the driving cam 120 drives the needle pitch seat 41 to rotate clockwise around the first fixed swing fulcrum O1 through the first connecting rod 71 and the second connecting rod 72, so as to change the position angle of the needle pitch seat 41, and the position angle of the needle pitch seat 41 directly controls the swing amplitude of the feeding crank 47 and the feeding shaft 42, that is, the movement amplitude of the tooth frame 20 and the feeding teeth 30 in the front and back directions, thereby controlling the needle pitch of the sewing machine. The needle gage 41 drives the stop plate 73 to rotate clockwise around the first fixed swing fulcrum O1, and the limit part 731 of the stop plate 73 moves upward and further away from the limit shock-absorbing block 77 of the fixed support 74 against the pulling force of the first spring 75. After the required needle pitch value is adjusted, the driving source 110 stops operating, the driving cam 120 is kept at the current position, the needle pitch base 41 is made to be stationary through the first link 71 and the second link 72, and the sewing machine keeps the adjusted needle pitch value. With the clockwise rotation of the needle pitch seat 41 in the view of fig. 9, the needle pitch value of the sewing machine is gradually reduced from the maximum needle pitch of the positive seam, passes through the zero needle pitch in the encrypted seam mode, and then enters the negative needle pitch in the backstitch mode until the maximum needle pitch of the backstitch is reduced; in the process, the stitch length value is gradually reduced, the smaller the stitch length value in the positive sewing and the smaller the stitch length in the positive sewing of the sewing machine, and the smaller the stitch length value in the reverse sewing and the larger the stitch length in the reverse sewing of the sewing machine. Therefore, within the allowable needle pitch range of the sewing machine, the driving source 110 controls the counterclockwise rotation and the clockwise rotation of the driving cam 120 to quickly perform the needle pitch adjustment, including the adjustment operation from the maximum positive stitch distance (+5) to the zero needle pitch, the adjustment operation from the maximum backstitch distance (-5) to the zero needle pitch, and the adjustment operation to the nearly zero needle pitch. In addition, in the process of adjusting the needle pitch within the allowable needle pitch range of the sewing machine, under the action of the mutual pulling of the driving source 110 and the first spring 75, the force of the driving torsion spring 76 sleeved at the hinge joint of the first connecting rod 71 and the second connecting rod 72 is overcome, so that the three points of the hinge joint of the driving cam 120 and the first connecting rod 71, the hinge joint of the first connecting rod 71 and the second connecting rod 72, and the hinge joint of the second connecting rod 72 and the needle pitch base 41 are always collinear.

When the sewing machine lifts the presser foot and supplies the material downwards, the driving source 110 drives the driving cam 120 to rotate clockwise from the view angle shown in fig. 10 and 11, the variable diameter driving surface 121 on the driving cam 120 is contacted and matched with the roller 82, and the driving cam 120 drives the needle gage base 41 to rotate counterclockwise around the first fixed swing fulcrum O1 through the first link 71 and the second link 72, the needle gage base 41 drives the stop plate 73 to swing downward, the limit part 731 on the stop plate 73 abuts against and contacts the limit shock-absorbing block 77 on the fixed support 74, as the driving source 110 drives the driving cam 120 to continue to rotate clockwise, an included angle is formed between the first link 71 and the second link 72 under the action of the driving torsion spring 76, and the three points of the hinge point of the driving cam 120 and the first link 71, the hinge point of the first link 71 and the second link 72, and the hinge point of the second link 72 and the needle gage seat 41 are not collinear. Meanwhile, the variable diameter driving surface 121 on the driving cam 120 enables the driving plate 81 to rotate clockwise around the first fixed swing fulcrum O1 through a ball, the driving plate 81 enables the presser foot lifting driving connecting rod 83 and the lower supply driving connecting rod 84 to move downwards, the presser foot lifting driving connecting rod 83 pulls the presser foot lifting pull rod 62 rightwards through the right lever 61, the presser foot lifting plate 64 is driven to move upwards through the left lever 63, and the pressing rod guide frame 65, the pressing rod 66 and the presser foot 90 are driven to move upwards together to realize presser foot lifting; meanwhile, the first chute 841 at the lower end of the lower driving connecting rod 84 moves downwards relative to the first axial screw 150, after the upper end of the first chute 841 is abutted against the first axial screw 150, the lower driving connecting rod 84 pushes the second tooth lifting connecting rod 54 to swing through the first axial screw 150 along with the continuous downward movement of the lower driving connecting rod 84, the bottom of the third chute 544 in the second tooth lifting connecting rod 54 moves relative to the third axial screw 170 penetrating through the first tooth lifting connecting rod 53, so that the rear end opening angle of the third chute 544 is upward, that is, the second tooth lifting connecting rod 54 moves downwards when swinging clockwise around the second axial screw 160, the second tooth lifting connecting rod 54 drives the tooth lifting crank 55 to swing downwards through the second axial screw 160, but the first tooth lifting connecting rod 53 does not move under the action of the second chute 531, the tooth lifting crank 55 drives the tooth lifting shaft 51 to swing together, and the tooth lifting shaft 51 moves downwards through the second tooth lifting transmission unit to drive the tooth rack 20 and the feeding tooth 30, the feeding teeth 30 are lowered to the lower part of the upper surface of the needle plate 140 and do not protrude from the tooth grooves of the needle plate 140, and the lower feeding and discharging action is realized. In addition, since the first link 71 and the second link 72 form an included angle therebetween, no power is transmitted between the driving cam 120 and the needle gage 41, the needle gage 41 is kept stationary, and the movement between the driving source 110 and the needle gage 41 is separated. Further, when the sewing machine lifts the presser foot and supplies the material downwards, if the sewing machine is not located at the maximum needle pitch of the front seam, when the driving source 110 drives the driving cam 120 to rotate clockwise, the driving cam 120 drives the needle pitch base 41 to rotate anticlockwise through the first connecting rod 71 and the second connecting rod 72, the needle pitch value of the sewing machine is gradually increased, the limiting part 731 on the stop plate 73 moves downwards in the direction close to the limiting damping block 77 on the fixed support 74, the first connecting rod 71 and the second connecting rod 72 are collinear, but no power transmission exists between the driving cam 120 and the roller 82, namely the driving cam 120 and the presser foot lifting mechanism 60, the driving cam 120 and the tooth lifting mechanism 50 are in the state of motion separation. The sewing machine may then cross the positive seam maximum gauge. Then, as the driving source 110 drives the driving cam 120 to continue to rotate clockwise, the contact surface on the limiting part 731 is abutted against the limiting damping block 77, an included angle is formed between the first connecting rod 71 and the second connecting rod 72, the driving cam 120 and the needle pitch seat 41 are in a motion separation state, and the needle pitch seat 41 does not rotate; however, the roller 82 is pushed upward by the driving cam 120, so that the driving cam 120 and the presser foot lifting mechanism 60, the driving cam 120 and the feed dog mechanism 50 are in moving engagement, and the feed dog 30 is automatically lowered below the upper surface of the needle plate 140 while the presser foot is lifted. After the material is discharged, the driving source 110 is reset to drive the driving cam 120 to rotate anticlockwise and reset, so that the first connecting rod 71 and the second connecting rod 72 are reset to be in a collinear state, the driving plate 81, the pressure raising and pressing foot driving connecting rod 83, the lower supply driving connecting rod 84 and the second tooth raising connecting rod 54 are reset, and the tooth raising crank 55, the tooth raising shaft 51, the tooth frame 20 and the feeding tooth 30 are reset.

In summary, the sewing machine according to the present application has the following advantages:

1. the rotation of the driving cam 120 can be controlled by controlling the driving source 110, needle pitch adjustment, seam densification, front seam, back seam, presser foot lifting and lower material supply and discharge are carried out by combining the first transmission clutch mechanism 70 and the second transmission clutch mechanism 80, mutual switching can be carried out at proper time, the roller 82 and the reducing driving surface 121 on the driving cam 120 are in rolling fit without impact phenomenon when the presser foot is lifted and the lower material supply and discharge are carried out, and the impact phenomenon is avoided when the needle pitch is adjusted, so that the problems of noise and damage caused by impact are avoided.

2. The needle pitch adjustment, the seam densification, the front seam, the back seam, the presser foot lifting and the lower feeding are realized by adopting one driving source 110, and only one reducing driving surface 121 needs to be processed on the driving cam 120, namely only one cam functional component is arranged on the driving cam 120.

3. When the sewing machine is in a presser foot lifting state and a lower material feeding and taking state, the first transmission clutch mechanism 70 consisting of the first connecting rod 71, the second connecting rod 72, the driving torsion spring 76, the stop plate 73, the fixed support 74 and the first spring 75 is in an included angle state between the first connecting rod 71 and the second connecting rod 72, and the needle distance seat 41 can be kept still regardless of the action of the driving source 110, so that the separation of the movement between the driving source 110 and the needle distance seat 41 is realized. When the sewing machine is in a state that the presser foot 90 is placed, the first link 71 and the second link 72 are in a collinear state, the driving source 110 pulls the first link 71, the second link 72 and the needle distance seat 41 upwards through the driving cam 120, and the control of the driving source 110 on the position angle of the needle distance seat 41 is realized by overcoming the pulling force of the first spring 75, so that the control on the needle distance of the sewing machine is realized.

4. The connection between the lower driving link 84 and the second feed dog link 54 is provided with a first sliding groove 841 on the lower driving link 84, which has the following functions: firstly, when the sewing machine is used for normal sewing, the driving plate 81 does not move, but the second feed lifting connecting rod 54 moves along with the feed lifting mechanism 50, and in the process, the first axial screw 150 slides on the first sliding groove 841 without impacting the groove bottom of the first sliding groove 841, so that the mechanisms do not interfere with each other; secondly, the function of idle stroke is achieved, a small amount of tooth lifting presser feet 90 are sometimes needed to facilitate the rotation of the sewing material direction in the sewing process, but the feeding teeth 30 do not need to descend at the moment, the first chute 841 of the lower supply driving connecting rod 84 moves downwards relative to the first axial screw 150 when the presser feet are lifted a small amount, the lower supply driving connecting rod 84 cannot drive the tooth lifting transmission component to move, and only when the presser feet 90 are lifted to a high height, the upper end of the first chute 841 can be abutted against the first axial screw 150, so that the lower supply and discharge movement is executed.

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 (14)

1. A sewing machine comprises a main shaft (10), a tooth rack (20), a feeding tooth (30) arranged on the tooth rack (20), a feeding mechanism (40) connected between the main shaft (10) and one end of the tooth rack (20), a tooth lifting mechanism (50) connected between the main shaft (10) and the other end of the tooth rack (20), a presser foot (90), and a presser foot lifting mechanism (60) connected with the presser foot (90), wherein the feeding mechanism (40) comprises a needle distance seat (41) with a first fixed swing fulcrum (O1), and is characterized in that: the needle gauge mechanism further comprises a driving source (110), a driving cam (120) driven by the driving source (110) to rotate, a first transmission clutch mechanism (70) and a second transmission clutch mechanism (80), wherein the first transmission clutch mechanism (70) acts between the driving cam (120) and the needle gauge seat (41), and the second transmission clutch mechanism (80) acts between the driving cam (120), a pressure lifting and pressing pin transmission part in the pressure lifting and pressing pin mechanism (60) and a tooth lifting and pressing transmission part in the tooth lifting mechanism (50);

when the first transmission clutch mechanism (70) enables power transmission between the driving cam (120) and the needle gage seat (41), the second transmission clutch mechanism (80) enables power transmission not to be achieved between the driving cam (120) and the pressure lifting pin transmission part and between the driving cam (120) and the tooth lifting transmission part; at the moment, the driving source (110) drives the driving cam (120) to rotate, and the driving cam (120) drives the needle pitch seat (41) to rotate around a first fixed swing fulcrum (O1) through the first transmission clutch mechanism (70);

when the second transmission clutch mechanism (80) enables power transmission between the driving cam (120) and the lifting and pressing foot transmission part and between the driving cam (120) and the lifting tooth transmission part, the first transmission clutch mechanism (70) enables no power transmission between the driving cam (120) and the needle gage seat (41); at the moment, the driving source (110) drives the driving cam (120) to rotate, the driving cam (120) drives the presser foot lifting mechanism (60) to act through the second transmission clutch mechanism (80) to lift the presser foot (90) upwards, and the driving cam (120) simultaneously drives the tooth lifting mechanism (50) to act through the second transmission clutch mechanism (80) to lower the tooth rack (20) and the feeding tooth (30);

the first transmission clutch mechanism (70) comprises a first connecting rod (71), a second connecting rod (72), a stop plate (73) fixed on the needle distance seat (41), a fixed support (74) fixed on the sewing machine shell (130), and a first spring (75), wherein two ends of the first connecting rod (71) are respectively hinged with the driving cam (120) and the second connecting rod (72), the second connecting rod (72) is hinged with the needle distance seat (41), a limiting part (731) capable of being abutted against the fixed support (74) is arranged on the stop plate (73), two ends of the first spring (75) are respectively connected with the stop plate (73) and the fixed support (74), and the stop plate (73) has a movement trend that the limiting part (731) moves towards the direction close to the fixed support (74); when the first connecting rod (71) and the second connecting rod (72) are collinear, the first transmission clutch mechanism (70) enables power transmission between the driving cam (120) and the needle gauge seat (41), and the limiting part (731) is not abutted with the fixed support (74); when the first connecting rod (71) and the second connecting rod (72) are not collinear, the first transmission clutch mechanism (70) enables the driving cam (120) and the needle gauge seat (41) to have no power transmission, and the limiting part (731) is abutted with the fixed support (74).

2. The sewing machine of claim 1, wherein: the driving source (110) is a motor, and the driving cam (120) is fixed on a motor shaft of the motor.

3. The sewing machine of claim 1, wherein: and a driving torsion spring (76) is sleeved at the hinged position of the first connecting rod (71) and the second connecting rod (72).

4. The sewing machine of claim 1, wherein: the limiting part (731) is positioned above the fixed support (74).

5. The sewing machine of claim 1, wherein: the end face of the fixed support seat (74) facing the limiting part (731) is fixed with a limiting damping block (77), the limiting part (731) is provided with a contact surface facing the fixed support seat (74), and the contact surface is a flat surface and can be abutted against the limiting damping block (77).

6. The sewing machine of claim 1, wherein: the feeding mechanism (40) comprises a feeding shaft (42) parallel to the main shaft (10), a first feeding transmission unit connected between the main shaft (10) and the feeding shaft (42), and a second feeding transmission unit connected between the feeding shaft (42) and the tooth rack (20); the first feeding transmission unit comprises a feeding eccentric wheel (43), a feeding connecting rod (44), a first swinging plate (45), a second swinging plate (46), a feeding crank (47) and a needle distance seat (41), wherein the feeding eccentric wheel (43), the feeding connecting rod (44), the feeding crank (47) are fixed on a feeding shaft (42), one end of the feeding connecting rod (44) is rotatably arranged on the periphery of the feeding eccentric wheel (43), the other end of the feeding connecting rod (44), one end of the first swinging plate (45) and one end of the second swinging plate (46) are coaxially hinged, the other end of the first swinging plate (45) is hinged with the needle distance seat (41), and the other end of the second swinging plate (46) is hinged with the feeding crank (47).

7. The sewing machine of claim 1, wherein: the second transmission clutch mechanism (80) comprises a driving plate (81) with a second fixed swing fulcrum (O2), a roller (82) rotatably mounted at one end of the driving plate (81), a pressure lifting and pressing pin driving connecting rod (83) and a lower supply driving connecting rod (84), the other end of the driving plate (81), one end of the pressure lifting and pressing pin driving connecting rod (83) and one end of the lower supply driving connecting rod (84) are coaxially hinged, the other end of the pressure lifting and pressing pin driving connecting rod (83) is connected with the pressure lifting and pressing pin transmission part, the other end of the lower supply driving connecting rod (84) is connected with the tooth lifting and driving part, and the outer peripheral surface of the driving cam (120) is provided with a section of variable diameter driving surface (121); when the roller (82) is in contact fit with a variable-diameter driving surface (121) on the driving cam (120), the second transmission clutch mechanism (80) enables power transmission to be achieved between the driving cam (120) and the pressure lifting and pressing foot transmission part and between the driving cam (120) and the tooth lifting and pressing tooth transmission part; when the roller (82) is not in contact fit with the variable-diameter driving surface (121) on the driving cam (120), the second transmission clutch mechanism (80) enables no power transmission between the driving cam (120) and the pressure lifting and pressing transmission part and between the driving cam (120) and the tooth lifting and pressing transmission part.

8. The sewing machine of claim 7, wherein: the peripheral surface of the driving cam (120) is provided with a groove part (122), and the groove part (122) is arranged adjacent to the variable diameter driving surface (121); when the roller (82) is not in contact fit with the variable diameter driving surface (121) on the driving cam (120), the roller (82) is positioned in the groove part (122) and is not in contact with the driving cam (120).

9. The sewing machine of claim 7, wherein: the lower driving connecting rod (84) is hinged to the tooth lifting transmission part through a first axial screw (150) parallel to the main shaft (10), a first sliding groove (841) extending up and down is formed in the lower end of the lower driving connecting rod (84), and the first axial screw (150) penetrates through the first sliding groove (841) and can be abutted to the upper end and the lower end of the first sliding groove (841).

10. The sewing machine of claim 1, wherein: the tooth lifting mechanism (50) comprises a tooth lifting shaft (51) parallel to the main shaft (10), a first tooth lifting transmission unit connected between the main shaft (10) and the tooth lifting shaft (51), and a second tooth lifting transmission unit connected between the tooth lifting shaft (51) and the tooth frame (20); the first lifting tooth transmission unit comprises a lifting tooth eccentric wheel (52) fixed on the main shaft (10), a first lifting tooth connecting rod (53), a second lifting tooth connecting rod (54) and a lifting tooth crank (55) fixed on a lifting tooth shaft (51), one end of the first lifting tooth connecting rod (53) is rotatably installed on the periphery of the lifting tooth eccentric wheel (52), the other end of the first lifting tooth connecting rod (53), the second lifting tooth connecting rod (54) and the lifting tooth crank (55) are coaxially hinged, the second lifting tooth connecting rod (54) is further hinged with the first lifting tooth connecting rod (53), and the second lifting tooth connecting rod (54) further forms the lifting tooth transmission part.

11. The sewing machine of claim 10, wherein: the first lifting tooth connecting rod (53), the second lifting tooth connecting rod (54) and the lifting tooth crank (55) are hinged through a second axial screw (160) parallel to the main shaft (10), a second sliding groove (531) extending up and down is formed in the lower end of the first lifting tooth connecting rod (53), and the second axial screw (160) penetrates through the second sliding groove (531); the first lifting tooth connecting rod (53) and the second lifting tooth connecting rod (54) are further hinged through a third axial screw (170) parallel to the main shaft (10), a third sliding groove (544) extending horizontally is formed in the second lifting tooth connecting rod (54), and the third axial screw (170) penetrates through the third sliding groove (544).

12. The sewing machine of claim 11, wherein: the second tooth lifting connecting rod (54) is concave and comprises a rod body portion (541) extending vertically, an upper rod arm portion (542) extending horizontally from the upper end of the rod body portion (541) and a lower rod arm portion (543) extending horizontally from the lower end of the rod body portion (541), the second axial screw (160) penetrates through the joint of the rod body portion (541) and the lower rod arm portion (543), and the third sliding groove (544) is formed in the upper end of the rod body portion (541) and faces away from one side of the upper rod arm portion (542).

13. The sewing machine of claim 11, wherein: the first lifting tooth transmission unit further comprises a second spring (56), and two ends of the second spring (56) are respectively connected with the first lifting tooth connecting rod (53) and the second lifting tooth connecting rod (54) to enable the third axial screw (170) to have a moving trend of moving towards the bottom of the third sliding chute (544).

14. The sewing machine of claim 1, wherein: the presser foot lifting mechanism (60) is provided with a right lever (61) with a third fixed swing fulcrum (O3), a presser foot lifting pull rod (62), a left lever (63) with a fourth fixed swing fulcrum (O4), a presser foot lifting plate (64), a pressure lever guide frame (65) and a pressure lever (66) extending up and down, the right lever (61) forms the presser foot lifting transmission component, the other end of the right lever (61) is hinged with one end of the presser foot lifting pull rod (62), the other end of the presser foot lifting pull rod (62) is hinged with one end of the left lever (63), the other end of the left lever (63) is hinged with the upper end of the presser foot lifting plate (64), a lifting hook part is arranged on the presser foot lifting plate (64), a connecting protruding part clamped with the lifting hook part is arranged on the pressure lever guide frame (65), and the guide frame (65) is fixed at the upper end of the pressure lever (66), the pressure foot (90) is arranged at the lower end of the pressure rod (66).

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