CN216765235U - Thread trimming and presser foot lifting driving mechanism in overedger - Google Patents

Abstract

The utility model provides a thread trimming and presser foot lifting driving mechanism in a overedger, and belongs to the technical field of sewing machines. The device comprises a motor, a driving wheel fixed on an output shaft of the motor, a first transmission mechanism linked with a trimming shaft and a second transmission mechanism linked with a presser foot shaft, wherein a first driving surface capable of driving the first transmission mechanism to act, a second driving surface capable of driving the second transmission mechanism to act and an idle stroke surface concentrically arranged with the output shaft of the motor are respectively arranged on the driving wheel, the first driving surface, the second driving surface and the idle stroke surface are respectively arranged at the edge of the driving wheel, the first driving surface and the second driving surface are both convex curved surfaces and are respectively connected with two sides of the idle stroke surface, when the first transmission mechanism is in a position contacted with the first driving surface, the second transmission mechanism is in a position contacted with the second driving surface, and when the first transmission mechanism is in a position contacted with the idle stroke surface, the second transmission mechanism is in a position contacted with the second driving surface. The device has the advantages of high matching precision, high whole machine assembly efficiency and the like.

Description

Thread trimming and presser foot lifting driving mechanism in overedger

Technical Field

The utility model belongs to the technical field of sewing machines, relates to an overlock sewing machine, and particularly relates to a driving mechanism for trimming and lifting a presser foot in the overlock sewing machine.

Background

Overedgers, also known as sewing machines, stacking machines and sewing machines, generally divide into three, four or five threads, whose main function is generally to prevent the sewing of the clothing from fluffing. The overlock machine comprises a presser foot mechanism and a thread trimming mechanism, wherein the presser foot mechanism comprises a rotatable presser foot shaft and a presser foot component connected to one end of the presser foot shaft, and the presser foot component can be lifted when the presser foot shaft rotates; the thread cutting mechanism comprises a rotatable thread cutting shaft and a cutter fixedly connected to one end of the thread cutting shaft, and when the thread cutting shaft rotates, a thread can be cut off by means of the cutter.

The traditional overedger adopts two electromagnets which are independently arranged to respectively drive a thread cutting shaft and a presser foot shaft, but the structure of the whole overedger is heavy and the cost is high. To this end, a conventional overlock machine has been modified in structure and proposed as a drive mechanism of patent application No. 202022394810.3 and an overlock machine including a first transmission assembly at least a part of which is movably disposed to drive a lift-press portion of the overlock machine to perform a lift-press operation; at least part of the second transmission component is movably arranged so as to drive the thread cutting part of the overedger to fall; the first pushing component is in transmission connection with the first transmission component so as to drive the first transmission component to move; the second pushing component is used for being in transmission connection with the second transmission assembly so as to drive the second transmission assembly to move; the driving part (motor) is provided with a rotatable output shaft, and the first pushing part and the second pushing part are both arranged on the output shaft to rotate under the driving of the driving part. Through the arrangement, the driving mechanism can respectively control the thread trimming and the presser foot lifting device by adopting one motor, two actions are completed, and the structure is simpler.

However, the above-mentioned drive mechanism and overedger also have disadvantages: the first pushing part is actually a first transmission cam, the first transmission cam is sleeved on the output shaft to push the first transmission assembly part to move through the first transmission cam, meanwhile, the second pushing part is actually a second transmission cam, the second transmission cam is sleeved on the output shaft to push the second transmission assembly to move through the second transmission cam, no matter the first transmission cam or the second transmission cam has processing errors (such as coaxiality of a central hole) more or less during machining, the first transmission cam and the second transmission cam have specific installation angles and position relations on the output shaft, the two factors are overlapped to enable the matching precision of the whole driving mechanism to be difficult to guarantee, and multiple times of debugging are needed during the assembly of the whole machine.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a driving mechanism for trimming and lifting a presser foot in a overedger, aiming at the problems in the prior art, and solving the problem of low assembly efficiency of the whole overedger caused by difficulty in ensuring the matching precision.

The purpose of the utility model can be realized by the following technical scheme:

a driving mechanism for trimming and lifting a presser foot in a overedger comprises a motor fixed on one side of a casing of the overedger, a driving wheel fixed on an output shaft of the motor, a first transmission mechanism linked with a trimming shaft and a second transmission mechanism linked with a presser foot shaft, the driving wheel is respectively provided with a first driving surface capable of driving the first transmission mechanism to act, a second driving surface capable of driving the second transmission mechanism to act and an idle stroke surface which is concentric with the output shaft of the motor, it is characterized in that the driving surface I, the driving surface II and the idle stroke surface are all arranged at the edge of the driving wheel, the driving surface I and the driving surface II are both convex curved surfaces and are respectively connected with the two sides of the idle stroke surface, when the first transmission mechanism is in the position of contacting the first driving surface, the second transmission mechanism is in the position of contacting the idle stroke surface, and when the first transmission mechanism is in a position contacted with the idle stroke surface, the second transmission mechanism is in a position contacted with the second driving surface.

In the initial state, the contact position of the first transmission mechanism and the driving wheel is at the joint of the first driving surface and the idle stroke surface, and the contact position of the second transmission mechanism and the driving wheel is at the joint of the second driving surface and the idle stroke surface. When the thread cutting is needed, the output shaft of the motor drives the driving wheel to rotate, so that the driving surface is initially contacted with the first transmission mechanism, the first transmission mechanism is driven to receive driving force along with the movement of the first driving surface on the first transmission mechanism, and the first transmission mechanism drives the thread cutting shaft to swing to complete thread cutting. In the process of trimming, the contact position of the second transmission mechanism and the driving wheel moves from the connection position of the second driving surface and the idle stroke surface to the idle stroke surface, and the second transmission mechanism is not subjected to acting force to keep the presser foot shaft still so as to avoid interference to trimming.

When the presser foot needs to be lifted, the output shaft of the motor rotates reversely, so that the contact position of the first transmission mechanism and the driving wheel moves back to the connection position of the first driving surface and the idle stroke surface, and the contact position of the second transmission mechanism and the driving wheel also moves back to the connection position of the second driving surface and the idle stroke surface. Then, the output shaft of the motor continues to rotate along the current direction, so that the second driving surface is in contact with the second transmission mechanism, the second transmission mechanism is subjected to a pushing force along with the movement of the second driving surface on the second transmission mechanism, and the second transmission mechanism drives the presser foot shaft to swing so as to complete the presser foot lifting action. In the process of lifting the presser foot, the contact position between the first transmission mechanism and the driving wheel moves from the connection position of the first driving surface and the idle stroke surface to the idle stroke surface, and the first transmission mechanism does not receive acting force to keep the wire shearing shaft still so as to avoid interfering the action of lifting the presser foot.

The first driving surface, the second driving surface and the idle stroke surface are arranged at the edge of the driving wheel simultaneously and are combined with the curvature, so that the driving mechanism can be matched with the first transmission mechanism to finish the wire shearing action and matched with the second transmission mechanism to finish the presser foot lifting work by only using one driving wheel, the first driving surface, the second driving surface and the idle stroke surface are processed on the single driving wheel and are positioned at the edge of the driving wheel, the processing error can be well controlled, the relative angle and the relative position between the first driving surface and the second driving surface are determined after the processing of the driving wheel is finished, the use of two transmission cams can be omitted, the time for adjusting the relative angle and the relative position between the two transmission cams during assembly is saved, and only the position between the first transmission mechanism and the driving wheel and the position between the second transmission mechanism and the driving wheel are required to be adjusted during assembly, the assembly efficiency is greatly improved.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the curvature of the first driving surface and the curvature of the second driving surface are respectively gradually increased along one end connected with the idle stroke surface towards the other end.

Through the arrangement, when the driving wheel rotates towards the direction of increasing the curvature of the driving surface, the driving wheel can gradually apply a driving force to the first transmission mechanism by virtue of the gradual increase of the curvature of the driving surface, so that the first transmission mechanism drives the wire cutting shaft to swing to complete the wire cutting action; when the driving wheel rotates towards the direction of increasing the curvature of the driving surface II, the driving wheel can gradually apply a driving force to the transmission mechanism II by means of the gradual increase of the curvature of the driving surface II, so that the transmission mechanism II drives the presser foot shaft to swing to complete the presser foot lifting action.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the length of the first driving surface is greater than that of the second driving surface, and the length of the idle stroke surface is greater than that of the first driving surface.

The rotating angle of the driving wheel required for completing the trimming is larger than that required for completing the lifting of the presser foot, so that the length of the idle stroke surface is set to be larger than that of the driving surface on the basis of setting the length of the driving surface I to be larger than that of the driving surface II, and the transmission mechanism II can be always in contact with the idle stroke surface to keep the presser foot shaft still in the process of completing the trimming by the movement of the driving surface I along the matching part.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the edge of the driving wheel is also provided with a first retaining surface and a second retaining surface which are both concentric with the rotation center of the driving wheel, the first retaining surface is connected with the first driving surface and is in smooth transition with the first driving surface, the second retaining surface is connected with the second driving surface and is in smooth transition with the second driving surface, the second driving mechanism is in contact with the idle stroke surface when the first driving mechanism is in contact with the first retaining surface, and the first driving mechanism is in contact with the idle stroke surface when the second driving mechanism is in contact with the second retaining surface.

When the driving wheel rotates from the contact of the first driving surface and the first transmission mechanism to the contact of the first holding surface and the first transmission mechanism, the first holding surface and the first driving surface are in smooth transition and are concentrically arranged with the rotation center of the driving wheel, which means that the wire cutting shaft is still kept in a wire cutting state at the moment; similarly, when the driving wheel rotates from the contact between the second driving surface and the second transmission mechanism to the contact between the second holding surface and the second transmission mechanism, the second holding surface and the second driving surface are in smooth transition and are concentrically arranged with the rotation center of the driving wheel, which means that the presser foot shaft is still kept in the state of lifting the presser foot at the moment.

In a normal state, in order to stably maintain the driving wheel at one position, the motor is required to generate a locking force, and at this time, the motor does not stop but the output shaft of the motor does not rotate. The driving mechanism is characterized in that the first holding surface and the second holding surface are arranged on the edge of the driving wheel, and the first holding surface and the second holding surface are arranged concentrically with the rotating center of the driving wheel, so that the curvatures of the first holding surface and the second holding surface are equal, and the motor can keep the thread cutting shaft in a thread cutting state for a period of time or keep the presser foot shaft in a presser foot lifting state for a period of time under the condition of outputting smaller locking force, thereby ensuring that the motor cannot be overheated. If the driving wheel is directly stopped at the position with the maximum curvature of the first driving surface to be contacted with the first transmission mechanism or the position with the maximum curvature of the second driving surface to be contacted with the second transmission mechanism, the motor needs to output larger locking force because the curvature of the first driving surface or the curvature of the second driving surface is changed, and the motor is overheated, so that the service life of the motor is influenced.

In the driving mechanism for trimming and lifting the presser foot in the overedger, one end of the motor shell is connected with a support fixed with the motor shell, the driving wheel is positioned on the inner side of the support, the output shaft of the motor is positioned above the presser foot shaft and is parallel to the presser foot shaft, the first transmission mechanism comprises a rotating seat hinged on the support, the rotating center line of the rotating seat is perpendicular to the output shaft of the motor and is positioned below the output shaft of the motor, the side part of the rotating seat is convexly provided with a matching part, the second transmission mechanism comprises a swing arm connected on the presser foot shaft, one end of the swing arm and the matching part are both positioned on the edge of the driving wheel and are abutted against the edge of the driving wheel, and the position of one end of the swing arm, which is contacted with the edge of the driving wheel, is always higher than the position of the matching part, which is contacted with the edge of the driving wheel.

The rotating seat is directly hinged on the support, the distance between the rotating seat and the driving wheel is shortened, the rotating center line of the presser foot shaft and the rotating seat is arranged to be positioned below the output shaft of the motor, the matching part is arranged on the side part of the rotating seat in a protruding mode, one end of the swing arm and the matching part are positioned on the edge of the driving wheel, the position, in contact with the edge of the driving wheel, of the swing arm I is always higher than the position, in contact with the edge of the driving wheel, of the matching part, the structure can be reasonably arranged in a limited space, and the driving mechanism is guaranteed to be capable of completing thread cutting action by matching with the transmission mechanism I and completing presser foot lifting work by matching with the transmission mechanism II by only one driving wheel. In addition, the fact that the rotating seat is hinged to the support also means that the rotating seat and the driving wheel are integrally assembled on the shell, the relative position between the central line of the rotating seat and the driving wheel is determined in advance, matching precision is guaranteed, and the assembling of the whole machine is simpler and more convenient, and assembling efficiency is improved. Moreover, the device has wider applicability and can adapt to the installation of different models.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the rotating seat is cylindrical, the matching part comprises a matching arm which is bent to be approximately parallel to the driving wheel after protruding along the radial direction of the rotating seat and a first wheel-shaped part connected with one side of the matching arm, and the rotating seat is sleeved with a first reset torsion spring which acts on the rotating seat and enables one edge of the first wheel-shaped part to be always abutted against the edge of the driving wheel.

Through the arrangement, the driving wheel can complete the presser foot lifting action by utilizing the driving surface II arranged on the edge, and simultaneously can drive the rotating seat to rotate by utilizing the driving surface I also arranged on the edge, so that the driving mechanism can complete the driving of the thread cutting action and the driving of the presser foot lifting action by utilizing only one driving wheel to improve the assembly efficiency of the whole machine.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the bracket comprises a first plate fixed with the shell of the motor and a second plate which is vertical to the first plate and fixed on the shell through a plurality of fastening screws, the rotating seat is hinged on the second plate, the side part of the rotating seat is also provided with a connecting part, and the first transmission mechanism also comprises a transmission rod with one end hinged with the connecting part and a swinging block which is hinged with the other end of the transmission rod and can be detachably connected on the trimming shaft.

After the motor is fixed on the casing, the whole transmission mechanism is also assembled on the casing at the same time, and only the swinging block is connected with the thread cutting shaft. Through the arrangement, the matching precision is further ensured, and the assembling efficiency is improved.

In the driving mechanism for trimming and lifting the presser foot in the overedger, one end of the first reset torsion spring is abutted against the side part of one of the fastening screws, and the other end of the first reset torsion spring is abutted against the connecting part.

Through the arrangement, the fastening screws for fixing the second plate on the shell are reasonably utilized, so that the elastic force of the first reset torsion spring sleeved on the rotating seat can stably act on the rotating seat, and the matching precision of the first transmission mechanism and the driving wheel is ensured.

In the driving mechanism for trimming and lifting the presser foot in the overedger, the swing arm comprises a sheet-shaped body connected to the presser foot shaft, an arm body protruding from the upper side of the sheet-shaped body and a wheel-shaped member II connected to one side of the arm body, the wheel-shaped member I and the wheel-shaped member II are in a substantially parallel state, the projection of the wheel-shaped member I and the wheel-shaped member II on the plate I are staggered, and the presser foot shaft is provided with a reset torsion spring II acting on the swing arm to enable the edge of the wheel-shaped member II to be always contacted with the edge of the driving wheel.

Through the arrangement, the driving wheel can drive the presser foot lifting action by utilizing the driving surface II arranged on the edge, and can drive the thread trimming action by utilizing the driving surface I also arranged on the edge, so that the matching precision is ensured, and the assembly efficiency of the whole machine is improved.

In the driving mechanism for trimming and lifting the presser foot in the overedger, a concave cavity is formed in the side part of the machine shell, the motor is arranged in the concave cavity, one end of the presser foot shaft extends into the concave cavity, the swing arm is connected to the end of the presser foot shaft, the connecting part comprises a first connecting piece protruding out of the side part of the rotating seat along the radial direction, a second connecting piece perpendicular to the first connecting piece and extending out of the concave cavity, and a third connecting piece perpendicular to the second connecting piece, and one end of the transmission rod is hinged to the third connecting piece.

Through the arrangement, the whole overedger is more compact in structure and smaller in volume. Meanwhile, the connecting piece II extends out of the concave cavity, and the rotating seat positioned in the concave cavity can be connected with the thread cutting shaft positioned outside the concave cavity smoothly, so that the rotating seat can drive the thread cutting shaft to swing to perform thread cutting operation when rotating.

Compared with the prior art, the driving mechanism for trimming and lifting the presser foot in the overedger has the following advantages:

1. the first driving surface, the second driving surface and the idle stroke surface are arranged at the edges of the driving wheels simultaneously and are combined with the curvature design, so that the driving mechanism can be matched with the first transmission mechanism to complete thread cutting action and matched with the second transmission mechanism to complete presser foot lifting work by only using one driving wheel, the machining error can be well controlled, the relative angle and the relative position between the first driving surface and the second driving surface are determined after the driving wheel is machined, the position between the first transmission mechanism and the driving wheel and the position between the second transmission mechanism and the driving wheel are adjusted during assembly, and the assembly efficiency is greatly improved;

2. the rotating seat is directly hinged on a bracket for fixing the motor on the shell, so that the transmission mechanism I and the driving wheel can be integrally installed on the shell, the relative position between the central line of the rotating seat and the driving wheel is determined in advance, the matching precision is ensured, and the assembly efficiency is improved simply and conveniently during the assembly of the whole machine.

Drawings

FIG. 1 is a schematic view of an overlock machine.

FIG. 2 is a schematic view of the drive mechanism for trimming and raising the presser foot in the present overlock machine.

Fig. 3 is a schematic view of the connection between the drive wheel, the first transmission mechanism and the shear spool.

Fig. 4 is a schematic view of the connection between the first transmission mechanism and the shear spool.

Fig. 5 is a schematic view of the connection between the driving wheel, the second transmission mechanism and the presser foot shaft.

Fig. 6 is a schematic view of the drive wheel.

FIG. 7 is a schematic view of the first wheel, the second wheel and the driving wheel when no trimming is performed and no foot lifting is performed.

FIG. 8 is a schematic view of the first wheel, the second wheel and the driving wheel engaged with each other when the trimming operation is performed.

FIG. 9 is a schematic view of the first wheel, the second wheel and the driving wheel cooperating with each other when the foot lifting operation is performed.

In the figure, 1, a housing; 1a, a concave cavity; 2. a presser foot shaft; 3. a presser foot assembly; 4. a thread cutting shaft; 5. a cutter; 6. a motor; 7. a drive wheel; 7a, an idle stroke surface; 7b, a first driving surface; 7c, a second driving surface; 7d, forming a first inner notch; 7e, an inner concave opening II; 7f, a first holding surface; 7g, a second holding surface; 8. swinging arms; 8a, a sheet-like body; 8b, an arm body; 8c, a second wheel; 9. a rotating seat; 9a, a matching part; 9a1, mating arm; 9a2, wheel one; 9b, a connecting part; 9b1 and a connecting sheet I; 9b2 and a connecting sheet II; 9b3 and a connecting sheet III; 10. a support; 10a, a first plate; 10b, a second plate; 11. fastening screws; 12. a connecting screw; 13. a first reset torsion spring; 14. a transmission rod; 15. a swing block; 16. and a second reset torsion spring.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2, 3, 6 and 7, the driving mechanism for trimming and lifting the presser foot in the overedger comprises a housing 1, a presser foot shaft 2, a presser foot component 3 connected to one end of the presser foot shaft 2 and a trimming spool 4 with one end connected with a cutter 5. The driving mechanism comprises a motor 6 fixed on one side of the shell 1, a driving wheel 7 fixed on an output shaft of the motor 6, a first transmission mechanism linked with the thread cutting shaft 4 and a second transmission mechanism linked with the presser foot shaft 2, the edge of the driving wheel 7 is provided with a idle stroke surface 7a which is concentric with the rotation center of the driving wheel 7, and a driving surface I7 b and a driving surface II 7c which are both convex curved surfaces, the driving surface I7 b and the driving surface II 7c are positioned at two sides of the idle stroke surface 7a, the idle stroke surface 7a is a section of circular arc surface, the curvature of the driving surface I7 b and the curvature of the driving surface II 7c are gradually increased towards the direction far away from the idle stroke surface 7a, an inner notch I7 d is formed between the driving surface I7 b and the idle stroke surface 7a, an inner notch II 7e is formed between the driving surface II 7c and the idle stroke surface 7a, and the inner notch I7 d and the inner notch II 7e are both arc-shaped notches in the embodiment. The first driving surface 7b can be matched with the first transmission mechanism, the second driving surface 7c can be matched with the second transmission mechanism, when the driving wheel 7 rotates, the first transmission mechanism is driven through the first driving surface 7b to drive the first shear wire shaft 4 to swing, the space-time stroke surface 7a is matched with the first transmission mechanism, and when the driving wheel 7 rotates, the second transmission mechanism is driven through the second driving surface 7c to drive the second compression pin shaft 2 to swing, the space-time stroke surface 7a is matched with the first transmission mechanism. The length of the first driving surface 7b is greater than that of the second driving surface 7c, and the length of the idle stroke surface 7a is greater than that of the first driving surface 7 b. The edge of the driving wheel 7 is also provided with a first retaining surface 7f and a second retaining surface 7g which are both concentric with the rotation center of the driving wheel 7, the first retaining surface 7f is connected with the first driving surface 7b and is in smooth transition, the second retaining surface 7g is connected with the second driving surface 7c and is in smooth transition, the second driving mechanism is in contact with the idle stroke surface 7a when the first driving mechanism is in contact with the first retaining surface 7f, and the first driving mechanism is in contact with the idle stroke surface 7a when the second driving mechanism is in contact with the second retaining surface 7 g.

Further, as shown in fig. 1 and 2, one end of the housing of the motor 6 is connected to a bracket 10 fixed to the housing 1, a cavity 1a is provided at one side of the housing 1, the motor 6 is disposed in the cavity 1a, and the bracket 10 is fixed to the bottom wall of the cavity 1 a. The drive wheel 7 is located the support 10 inboard, the output dress of motor 6 parallels with presser foot axle 2, drive mechanism two is including connecting the swing arm 8 on presser foot axle 2, drive mechanism one is including articulating on support 10 and rotation center line and 6 output shaft looks vertically rotation seat 9 of motor, it is equipped with cooperation portion 9a to rotate the 9 lateral parts of seat, 8 one ends of swing arm all lean on with 7 marginal offsets of drive wheel with cooperation portion 9a, and cooperation portion 9a is located interior notch 7d department when 8 one end of swing arm is located interior notch two 7e departments. The bracket 10 specifically comprises a first plate 10a fixed at one end of the housing of the motor 6 and a second plate 10b perpendicular to the first plate 10a and fixed on the bottom wall of the cavity 1a through a plurality of fastening screws 11, and the rotating seat 9 is hinged on the second plate 10 b.

Further, as shown in fig. 3 and 4, the rotating base 9 is cylindrical, and the rotating base 9 is hinged to the second plate 10b through a connecting screw 12 passing through the rotating base 9 and the second plate 10b and screwed into the casing 1. The matching part 9a comprises a matching arm 9a1 which is formed by bending after protruding along the radial direction of the rotating seat 9 and a wheel-shaped part one 9a2 connected to one side of the end part of the matching arm 9a1, the matching part 9a is positioned below the rotating central line of the driving wheel 7, and the rotating seat 9 is sleeved with a first reset torsion spring 13 which can enable the edge of the wheel-shaped part one 9a2 to be always abutted against the edge of the driving wheel 7. The side of the rotating seat 9 is also provided with a connecting part 9b, and the first transmission mechanism further comprises a transmission rod 14 with one end hinged with the connecting part 9b and a swinging block 15 which is hinged with the other end of the transmission rod 14 and can be detachably connected with the other end of the shear wire shaft 4. The swing block 15 is provided with two parallel mounting holes, one of the mounting holes is used for being connected with the shear line shaft 4, the other mounting hole is used for being hinged with the transmission rod 14 through a hinge shaft, the swing block 15 is further provided with a straight groove for communicating the two mounting holes, the swing block 15 is further provided with a locking hole in a penetrating mode, the locking hole is communicated with the straight groove (the locking hole is perpendicular to the mounting hole), when a locking screw is connected into the locking hole, the straight groove can be folded, the hole walls of the two mounting holes are tightly held between the hinge shaft and the shear line shaft 4 to be fixed, one end of the first reset torsion spring 13 abuts against the side portion of one of the fastening screws 11, and the other end of the first reset torsion spring 13 abuts against the connecting portion 9 b. The connecting part 9b comprises a connecting piece I9 b1 protruding from the side part of the rotating seat 9 along the radial direction, a connecting piece II 9b2 perpendicular to the connecting piece I9 b1 and extending out of the cavity 1a, and a connecting piece III 9b3 perpendicular to the connecting piece II 9b2, and one end of the transmission rod 14 is hinged to the connecting piece III 9b 3.

Further, as shown in fig. 1 and 5, one end of the presser foot shaft 2 extends into the cavity 1a and is located below the motor 6, the swing arm 8 is connected to one end of the presser foot shaft 2 extending into the cavity 1a, that is, the swing arm 8 is located in the cavity 1a, one end of the swing arm 8 is located at the edge of the driving wheel 7, the presser foot shaft 2 is provided with a second reset torsion spring 16 which enables one end of the swing arm 8 to always abut against the edge of the driving wheel 7, and the position where one end of the swing arm 8 contacts the driving wheel 7 is always higher than the position where the matching part 9a contacts the edge of the driving wheel 7. Specifically, the swing arm 8 comprises a sheet-shaped body 8a connected to the presser foot shaft 2, an arm body 8b protruding from the upper side of the sheet-shaped body 8a, and a second wheel-shaped member 8c connected to one side of the end of the arm body 8b, one end of the second reset torsion spring 16 abuts against the bottom wall of the cavity 1a, the other end of the second reset torsion spring 16 abuts against the lower side of the sheet-shaped body 8a, and the edge of the second wheel-shaped member 8c always abuts against the edge of the driving wheel 7 under the elastic action of the second reset torsion spring 16. The first wheel 9a2 and the second wheel 8c are in a substantially parallel state, the first wheel 9a2 and the second wheel 8c are projected on the first plate 10a in a staggered manner, and both the first wheel 9a2 and the second wheel 8c are bearings in this embodiment.

In the initial state, as shown in fig. 7, the first wheel 9a2 is located at the first concave opening 7d between the first driving surface 7b and the idle stroke surface 7a and abuts against the driving wheel 7 under the elastic force of the first return torsion spring 13, and the second wheel 8c is located at the second concave opening 7e between the second driving surface 7c and the idle stroke surface 7a and abuts against the driving wheel 7 under the elastic force of the second return torsion spring 16.

When a thread is required to be cut, the output shaft of the motor 6 drives the driving wheel 7 to rotate, so that the driving surface one 7b is in contact with the wheel-shaped member one 9a2, and since the curvature of the driving surface one 7b gradually increases from one end of the driving surface one 7b connected with the idle stroke surface 7a to the other end, the wheel-shaped member one 9a2 is pushed downwards along with the movement of the driving surface one 7b on the wheel-shaped member one 9a2, so that the matching part 9a is pressed downwards to rotate the rotating seat 9, the connecting part 9b is lifted upwards along with the driving surface one and pulls the transmission rod 14 upwards through the hinge joint with the transmission rod 14, and the transmission rod 14 drives the thread cutting shaft 4 to swing so that the thread cutting knife 5 completes the thread cutting action, which is shown in fig. 8. In the process of trimming, the idle stroke surface 7a is contacted with the second wheel-shaped part 8c, the second wheel-shaped part 8c is not stressed, so that the swing arm 8 is kept still, and the presser foot shaft 2 is kept still to avoid interfering the trimming action.

When the presser foot needs to be lifted, the output shaft of the motor 6 rotates reversely, so that the contact position of the wheel member one 9a2 and the driving wheel 7 moves back to the inner concave opening one 7d between the driving surface one 7b and the idle stroke surface 7a, and then the contact position of the wheel member two 8c and the driving wheel 7 moves back to the inner concave opening two 7e between the driving surface two 7c and the idle stroke surface 7a again, and the state is shown in fig. 7. Then, the output shaft of the motor 6 continues to rotate in the current direction, so that the second driving surface 7c is in contact with the second wheel 8c, and since the curvature of the second driving surface 7c gradually increases towards the end connected with the idle stroke surface 7a towards the other end, the second wheel 8c is subjected to an urging force along with the movement of the second driving surface 7c on the second wheel 8c, so that the swing arm 8 can be driven to swing to drive the presser foot shaft 2 to rotate, and the presser foot assembly 3 is gradually lifted upwards in the rotation process of the presser foot shaft 2, which is shown in fig. 9. In the process of lifting the presser foot, the idle stroke surface 7a is contacted with the wheel member one 9a2, the wheel member one 9a2 is not stressed, so that the rotating seat 9 is kept still, and the bobbin 4 is kept still to avoid interfering the action of lifting the presser foot.

The specific embodiments described herein are merely illustrative of the spirit of the utility model. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the utility model as defined in the appended claims.

Claims (10)

1. A driving mechanism for trimming and lifting a presser foot in an overlock machine comprises a motor (6) fixed on one side of a shell (1) of the overlock machine, a driving wheel (7) fixed on an output shaft of the motor (6), a first transmission mechanism linked with a trimming shaft (4) and a second transmission mechanism linked with a presser foot shaft (2), wherein a first driving surface (7b) capable of driving the first transmission mechanism to act, a second driving surface (7c) capable of driving the second transmission mechanism to act and a free stroke surface (7a) concentrically arranged with the output shaft of the motor (6) are respectively arranged on the driving wheel (7), and the driving surface (7b), the second driving surface (7c) and the free stroke surface (7a) are all arranged at the edge of the driving wheel (7), are convex curved surfaces and are respectively connected with two sides of the free stroke surface (7a), when the first transmission mechanism is in a position contacting with the first driving surface (7b), the second transmission mechanism is in a position contacting with the idle stroke surface (7a), and when the first transmission mechanism is in a position contacting with the idle stroke surface (7a), the second transmission mechanism is in a position contacting with the second driving surface (7 c).

2. The driving mechanism for trimming and raising the presser foot in a hemming machine according to claim 1 wherein the curvature of the first driving surface (7b) and the curvature of the second driving surface (7c) are each gradually increased toward the other end along the end connected to the idle stroke surface (7 a).

3. The driving mechanism for trimming and raising the presser foot in a overedger according to claim 2, wherein the length of the first driving surface (7b) is longer than the second driving surface (7c), and the length of the idle stroke surface (7a) is longer than the length of the first driving surface (7 b).

4. The thread trimming and presser foot lifting drive mechanism of overlock sewing machine as claimed in claim 3, characterized in that the edge of said drive wheel (7) further has a first retaining face (7f) and a second retaining face (7g) both disposed concentrically with the output shaft of the motor (6), the first retaining face (7f) is connected with the first drive face (7b) and smoothly transited therebetween, the second retaining face (7g) is connected with the second drive face (7c) and smoothly transited therebetween, the second drive mechanism is in a contact position with the idle stroke face (7a) when the first drive mechanism is in a contact position with the first retaining face (7f), and the first drive mechanism is in a contact position with the idle stroke face (7a) when the second drive mechanism is in a contact position with the second retaining face (7 g).

5. The driving mechanism for trimming and raising the presser foot in the overedger according to claim 1, 2, 3 or 4, characterized in that one end of the shell of the motor (6) is connected with a bracket (10) fixed with the shell (1), the driving wheel (7) is positioned at the inner side of the bracket (10), the output shaft of the motor (6) is positioned above the presser foot shaft (2) and is parallel to the same, the first transmission mechanism comprises a rotating seat (9) hinged on the bracket (10), the rotating center line of the rotating seat (9) is vertical to the output shaft of the motor (6) and is positioned below the output shaft of the motor (6), the lateral part of the rotating seat (9) is convexly provided with a matching part (9a), the second transmission mechanism comprises a swing arm (8) connected on the presser foot shaft (2), one end of the swing arm (8) and the matching part (9a) are both positioned at the edge of the driving wheel (7) and are abutted against the edge of the driving wheel (7), the position of one end of the swing arm (8) contacting with the edge of the driving wheel (7) is always higher than the position of the matching part (9a) contacting with the edge of the driving wheel (7).

6. The driving mechanism for trimming and raising the presser foot in the overedger according to claim 5, wherein the rotating seat (9) is cylindrical, the engaging portion (9a) comprises an engaging arm (9a1) which is protruded along the radial direction of the rotating seat (9) and then bent to be substantially parallel to the driving wheel (7) and a first wheel-shaped member (9a2) connected to one side of the engaging arm (9a1), and the rotating seat (9) is sleeved with a first restoring torsion spring (13) which acts on the rotating seat (9) to enable the edge of the first wheel-shaped member (9a2) to be always abutted against the edge of the driving wheel (7).

7. The driving mechanism for trimming and raising the presser foot in the overedger according to claim 6, characterized in that the bracket (10) comprises a first plate (10a) fixed with the housing of the motor (6) and a second plate (10b) perpendicular to the first plate (10a) and fixed on the machine shell (1) through a plurality of fastening screws (11), the rotating seat (9) is hinged on the second plate (10b), the side of the rotating seat (9) is further provided with a connecting part (9b), the driving mechanism further comprises a driving rod (14) with one end hinged with the connecting part (9b) and a swinging block (15) hinged with the other end of the driving rod (14) and detachably connected on the trimming shaft (4).

8. The driving mechanism for trimming and raising the presser foot in a overedger according to claim 7, wherein one end of the first reset torsion spring (13) abuts against the side of one of the fastening screws (11), and the other end of the first reset torsion spring (13) abuts against the connecting portion (9 b).

9. The driving mechanism for trimming and raising the presser foot in the overedger according to claim 6, wherein the swing arm (8) comprises a sheet-like body (8a) connected to the presser foot shaft (2), an arm body (8b) protruding from the upper side of the sheet-like body (8a), and a wheel-like member II (8c) connected to one side of the arm body (8b), the wheel-like member I (9a2) and the wheel-like member II (8c) are in a substantially parallel state, the projections of the wheel-like member I (9a2) and the wheel-like member II (8c) on the plate I (10a) are staggered, and a reset torsion spring II (16) acting on the swing arm (8) to make the edge of the wheel-like member II (8c) always contact with the edge of the driving wheel (7) is arranged on the presser foot shaft (2).

10. The driving mechanism for trimming and raising the presser foot in an overlock machine according to claim 7, wherein the side of the housing (1) is provided with a cavity (1a), the motor (6) is arranged in the cavity (1a), one end of the presser foot shaft (2) extends into the cavity (1a) and the swing arm (8) is connected to the end of the presser foot shaft (2), the connecting part (9b) comprises a first connecting piece (9b1) which radially protrudes out of the side of the rotating base (9), a second connecting piece (9b2) which is perpendicular to the first connecting piece (9b1) and extends out of the cavity (1a), and a third connecting piece (9b3) which is perpendicular to the second connecting piece (9b2), and one end of the transmission rod (14) is hinged to the third connecting piece (9b 3).

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