Driving device of overedger

Abstract

The utility model provides a driving device of an overedger, and belongs to the technical field of sewing machines. The problem that an existing overedger has many parts is solved. The driving device of the overedger comprises a motor and a transmission shaft, the motor can drive the transmission shaft to rotate, the transmission shaft is connected with a tooth height adjusting mechanism, the transmission shaft is further fixedly connected with a stitch length crank which can abut against and drive a stitch length adjusting mechanism, and the stitch length crank can be separated from the stitch length adjusting mechanism in the rotating process of the transmission shaft. According to the driving device of the overedger, transmission parts between the motor and the tooth height adjusting mechanism and between the motor and the stitch length adjusting mechanism are simplified, so that the transmission shaft is used for tooth height adjustment of feeding teeth and stitch length adjustment, and the structure of the overedger is simplified.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing machines and relates to a driving device for an overlock sewing machine. Background Art

[0002] A sewing machine is a machine that stitches sewing materials with sewing threads. Overlock sewing means that the overlock sewing thread and the curved sewing thread are self-connected and interconnected to edge or stitch the sewing material. An overlock sewing machine is a sewing machine that realizes overlock sewing and is a common sewing machine. The overlock sewing machine is provided with a thread cutting mechanism, a presser foot lifting mechanism, a tooth height adjusting mechanism, a stitch length adjusting mechanism, etc. With the development of automation, these mechanisms have been gradually improved and equipped with drivers, and the drivers include motors, electromagnets, cylinders, oil cylinders, etc.

[0003] Chinese patent literature discloses an automatic presser foot lifting, thread cutting, tooth height adjusting, and stitch length adjusting mechanism applicable to an overlock sewing machine [Application No.: CN202211636581.9; Publication No.: CN 115852595A], a stepping motor and a main shaft. A stitch length mechanism limit cam, a thread cutting mechanism driving cam, a presser foot mechanism driving cam, and a tooth adjusting mechanism driving cam are arranged on the output shaft of the stepping motor. A stitch length transmission mechanism is used to act on the stitch length mechanism limit cam to realize the adjustment of the stitch length. The stitch length transmission mechanism includes a cam follower, a first stitch length adjusting lever, a transmission shaft, a second stitch length adjusting lever, a stitch length adjusting link, a third stitch length adjusting lever, a torsion spring, a feeding mechanism, a stitch length adjusting shaft, and a rack. The feeding mechanism includes a split feeding eccentric cam, a stitch length eccentric cam, a disc spring, and a nut. The stitch length can be changed by changing the superposition eccentricity of the feeding eccentric cam and the stitch length eccentric cam. A thread cutting transmission mechanism is used to act on the thread cutting mechanism driving cam and transmit motion to the thread cutting knife mechanism to realize the control of thread cutting. The thread cutting transmission mechanism includes a first thread cutting lever for transmitting the thread cutting action, a metal ball, a second thread cutting lever, a thread cutting link, a torsion spring, and a third thread cutting lever. A presser foot lifting transmission mechanism is used to act on the presser foot mechanism driving cam to realize the lifting and falling actions of the presser foot mechanism. The presser foot mechanism includes a cam follower, a presser foot lifting lever, a limit retaining ring, a presser foot shaft, and a presser foot arm. A tooth adjusting transmission mechanism is used to act on the tooth adjusting mechanism driving cam to realize the height adjustment of the tooth frame mechanism. The tooth adjusting transmission mechanism includes a ratchet wheel and a ratchet pin arranged on the ratchet wheel, a first tooth adjusting lever, a first tooth adjusting link, a second tooth adjusting lever, a bushing, a third tooth adjusting lever, a second tooth adjusting link, and a tooth adjusting eccentric shaft. One end of the tooth frame mechanism is provided with a tooth mechanism.

[0004] In the above mechanism, the tooth adjusting transmission mechanism and the stitch length transmission mechanism are independently arranged, involving more parts, and the structure of the overlock sewing machine needs to be simplified. Content of the Utility Model

[0005] The object of the present utility model is to address the above problems existing in the prior art, and a driving device for an overlock sewing machine is proposed, and the technical problem to be solved is how to simplify the structure of the overlock sewing machine.

[0006] The object of the present utility model can be achieved by the following technical solutions:

[0007] A driving device for an overlock sewing machine, the overlock sewing machine includes a tooth height adjusting mechanism and a stitch pitch adjusting mechanism, the driving device of the overlock sewing machine includes a motor and a transmission shaft, the motor can drive the transmission shaft to rotate, the transmission shaft is connected to the tooth height adjusting mechanism, and it is characterized in that the transmission shaft is also fixedly connected with a stitch pitch crank that can abut against and drive the stitch pitch adjusting mechanism, and the stitch pitch crank can be separated from the stitch pitch adjusting mechanism during the rotation of the transmission shaft.

[0008] During the sewing process of the overlock sewing machine, when it is necessary to adjust the tooth height of the feed dog, the rotation range of the transmission shaft is controlled so that the stitch pitch crank is separated from the stitch pitch adjusting mechanism. At this time, the rotation of the transmission shaft will not drive the stitch pitch adjusting mechanism to act, and the sewing stitch pitch remains unchanged. Since the transmission shaft is connected to the tooth height adjusting mechanism, the rotation of the transmission shaft can drive the tooth height adjusting mechanism to act, thereby changing the tooth height of the feed dog. After the tooth height of the feed dog is adjusted, the motor does not move, so that the tooth height of the feed dog remains in the adjusted state. When it is necessary to adjust the stitch pitch, the transmission shaft rotates so that the stitch pitch crank abuts against and acts on the stitch pitch adjusting mechanism. After the stitch pitch adjusting mechanism acts, the stitch pitch is adjusted. After the stitch pitch is adjusted, the transmission shaft rotates in the reverse direction and returns to the position before the stitch pitch adjustment, so that the tooth height state of the feed dog is restored to the state before the stitch pitch adjustment. The driving device of the present overlock sewing machine simplifies the transmission parts between the motor and the tooth height adjusting mechanism and between the motor and the stitch pitch adjusting mechanism, so that the transmission shaft is used for both the tooth height adjustment of the feed dog and the stitch pitch adjustment, making the transmission shaft drive two functions, and simplifying the structure of the overlock sewing machine.

[0009] In the above driving device of the overlock sewing machine, a common cam is fixedly connected to the rotating shaft of the motor, and a first cam portion for driving the transmission shaft is provided on the common cam. The contour surface of the first cam portion has a first base circle surface, a first working surface, a transition surface, and a first equal-diameter surface that are sequentially connected in the circumferential direction; on the contour surface of the first cam portion, the radius of the first base circle surface is the smallest, the radius of the first equal-diameter surface is the largest, and the radii of the first working surface and the transition surface both gradually increase in the direction from the first base circle surface to the first equal-diameter surface; when the first working surface acts on the transmission shaft, the stitch pitch crank is separated from the stitch pitch adjusting mechanism, and when the first equal-diameter surface acts on the transmission shaft, the stitch pitch crank abuts against the stitch pitch adjusting mechanism.

[0010] During the rotation of the common cam, the drive shaft does not move when the first base circle surface acts on the drive shaft; the drive shaft rotates when the first working surface acts on the drive shaft. At this time, the stitch pitch crank and the stitch pitch adjusting mechanism are in a separated state, the stitch pitch adjusting mechanism does not move, and the tooth height adjusting mechanism acts. The tooth height of the feed dog can be adjusted through the first working surface to adapt to different sewing material thicknesses; the drive shaft rotates when the transition surface acts on the drive shaft. At this time, the stitch pitch crank and the stitch pitch adjusting mechanism transition from a separated state to an abutting state, and the tooth height of the feed dog drops to the lowest position. After the stitch pitch crank and the stitch pitch adjusting mechanism abut, the stitch pitch adjusting mechanism is driven to act; the drive shaft does not move when the first equal-diameter surface acts on the drive shaft. At this time, the stitch pitch adjusting mechanism reaches the stitch pitch adjusting position, and the main shaft of the overlock sewing machine is rotated to adjust the stitch pitch. The teeth of the feed dog remain at the lowest position, that is, the teeth are lowered. The setting of the common cam enables one cam to be used for both the tooth height adjustment of the feed dog and the stitch pitch adjustment, making the common cam drive two functions, which simplifies the structure of the overlock sewing machine.

[0011] In the drive device of the above-mentioned overlock sewing machine, the overlock sewing machine further includes a presser foot lifting mechanism. A second cam portion for driving the presser foot lifting mechanism is further provided on the common cam. The contour surface of the second cam portion has a second base circle surface, a second working surface, and a second equal-diameter surface that are sequentially connected along the circumferential direction; on the contour surface of the second cam portion, the radius of the second base circle surface is the smallest, the radius of the second equal-diameter surface is the largest, and the radius of the second working surface gradually increases along the direction from the second base circle surface to the second equal-diameter surface; when the first working surface acts on the drive shaft, the second base circle surface acts on the presser foot lifting mechanism, and when the first equal-diameter surface acts on the drive shaft, the second equal-diameter surface acts on the presser foot lifting mechanism.

[0012] During the rotation of the common cam, the presser foot does not move when the second base circle surface acts on the presser foot lifting mechanism; when the second working surface acts on the presser foot lifting mechanism, the presser foot lifting mechanism acts to lift the presser foot; the presser foot lifting mechanism does not move when the second equal-diameter surface acts on the presser foot lifting mechanism, and the presser foot is lifted to the highest position. During the process of lifting the presser foot, when the second base circle surface acts on the presser foot lifting mechanism and the first working surface acts on the drive shaft, the presser foot is not lifted and remains in the lowered state. At this time, the tooth height of the feed dog can be adjusted; when the second working surface acts on the presser foot lifting mechanism and the transition surface of the first cam portion acts on the drive shaft, the presser foot is lifted while the teeth of the feed dog are lowered, and at the same time, the stitch pitch crank and the stitch pitch adjusting mechanism transition from a separated state to an abutting state; when the second equal-diameter surface acts on the presser foot lifting mechanism while the first equal-diameter surface acts on the drive shaft, at this time, the presser foot is lifted to the highest, the teeth of the feed dog are lowered to the lowest, and the stitch pitch adjusting mechanism reaches the stitch pitch adjusting position. The stitch pitch can be adjusted by rotating the main shaft of the overlock sewing machine. The rotation of the motor drives the drive shaft to rotate through the common cam, thereby performing the tooth height adjustment and stitch pitch adjustment of the feed dog, and also lifting the presser foot through the common cam. The common cam drives three functions, which simplifies the structure of the overlock sewing machine.

[0013] In the driving device of the above-mentioned overlock sewing machine, the overlock sewing machine further includes a thread cutting mechanism. A thread cutting cam for driving the thread cutting mechanism is also fixedly connected to the rotating shaft of the motor. When the thread cutting cam drives the thread cutting mechanism to act, the first base circle surface acts on the transmission shaft and the second base circle surface acts on the presser foot lifting mechanism. When the motor rotates for thread cutting, the transmission shaft and the presser foot lifting mechanism do not move. Such a setting enables one motor to be used not only for adjusting the tooth height of the feed dog and the stitch pitch, but also for lifting the presser foot and cutting the thread. One motor realizes one driving four, which simplifies the structure of the overlock sewing machine.

[0014] In the driving device of the above-mentioned overlock sewing machine, the stitch pitch adjusting mechanism includes a stitch pitch connecting rod slidably hinged to the housing of the overlock sewing machine. The stitch pitch connecting rod is perpendicular to the transmission shaft, and one end of the stitch pitch connecting rod faces and can abut against the stitch pitch crank.

[0015] Since the movement range of the stitch pitch connecting rod is limited, when the stitch pitch crank rotates out of the movement range of the stitch pitch connecting rod, the stitch pitch crank is separated from the stitch pitch connecting rod. At this time, the height of the feed dog can be adjusted. Through the cooperation of the stitch pitch crank and the stitch pitch connecting rod, the transmission shaft is used not only for adjusting the tooth height of the feed dog, but also for adjusting the stitch pitch, which simplifies the structure of the overlock sewing machine.

[0016] In the driving device of the above-mentioned overlock sewing machine, the tooth height adjusting mechanism includes a tooth adjusting crank fixedly connected to the transmission shaft. The tooth adjusting crank and the stitch pitch crank are located at the same end of the transmission shaft. In this way, during the assembly process of the overlock sewing machine, it is convenient to adjust the relative circumferential position of the adjusting crank and the stitch pitch crank on the transmission shaft, so as to realize the one-driving-two function of the transmission shaft.

[0017] In the driving device of the above-mentioned overlock sewing machine, a transmission connecting rod is hinged to the housing of the overlock sewing machine. The first cam portion acts on the transmission connecting rod. A common crank is fixedly connected to the transmission shaft, and an intermediate connecting rod is hinged between the common crank and the transmission connecting rod. The transmission of motion is realized through the transmission connecting rod, the intermediate connection and the common crank, so that the rotation of the motor drives the rotation of the transmission shaft.

[0018] In the driving device of the above-mentioned overlock sewing machine, two support blocks are fixedly connected to the housing of the overlock sewing machine. The transmission shaft is arranged through the two support blocks. One end of the transmission shaft extends out of one of the support blocks and is sequentially connected to the tooth adjusting crank and the stitch pitch crank. The other end of the transmission shaft extends out of the other support block and is connected to the common crank. The two support blocks form supports at two positions for the transmission shaft, so that the transmission shaft works stably. The common crank and the stitch pitch crank are respectively installed at both ends of the transmission shaft, which makes it convenient to install and debug the transmission shaft, the common crank, the tooth adjusting crank and the stitch pitch crank.

[0019] In the driving device of the above-mentioned overlock sewing machine, two limiting rings are fixed on the transmission shaft between two supporting blocks, and the two limiting rings are respectively abutted against the two supporting blocks. The limiting rings have an axial limiting effect on the transmission shaft, avoiding axial displacement of the transmission shaft during operation and affecting the working stability of the driving device.

[0020] Compared with the prior art, the utility model has the following advantages:

[0021] The tooth height adjustment and stitch pitch adjustment of the feed dog are realized by driving with one transmission shaft, enabling the transmission shaft to drive two functions. One common cam can be used for the tooth height adjustment, stitch pitch adjustment and presser foot lifting of the feed dog, and the common cam realizes one driving three functions. One motor can be used for the tooth height adjustment, stitch pitch adjustment, presser foot lifting and thread trimming of the feed dog, and the motor realizes one driving four functions. This can reduce parts and simplify the structure of the overlock sewing machine. Description of the Drawings

[0022] Figure 1 is a perspective view of the first embodiment of the driving device of this overlock sewing machine when installed on the machine shell.

[0023] Figure 2 is a perspective view of the connection of the first embodiment of the driving device of this overlock sewing machine, the thread trimming mechanism, the presser foot lifting mechanism, the tooth height adjustment mechanism and the stitch pitch adjustment mechanism.

[0024] Figure 3 is a partial perspective view at the motor shaft of the first embodiment of the driving device of this overlock sewing machine.

[0025] Figure 4 is a perspective view of the common cam of the first embodiment of the driving device of this overlock sewing machine.

[0026] Figure 5 is a position relationship diagram of each component in the first embodiment of the driving device of this overlock sewing machine.

[0027] In the figure, 1. Machine shell; 2. Thread trimming mechanism; 2a. Thread trimming knife; 2b. Thread trimming roller; 3. Presser foot lifting mechanism; 3a. Presser foot; 3b. Presser foot lifting roller; 4. Tooth height adjustment mechanism; 4a. Feed dog; 4b. Tooth adjustment crank; 5. Stitch pitch adjustment mechanism; 5a. Feed eccentric wheel assembly; 5b. Stitch pitch connecting rod; 5c. Stitch pitch adjustment shaft; 5d. Stitch pitch adjustment crank; 5e. Stitch pitch adjustment plate; 6. Motor; 6a. Shaft; 7. Transmission shaft; 8. Stitch pitch crank; 9. Common cam; 9a. First cam part; 9a1. First base circle surface; 9a2. First working surface; 9a3. Transition surface; 9a4. First equal diameter surface; 9b. Second cam part; 9b1. Second base circle surface; 9b2. Second working surface; 9b3. Second equal diameter surface; 10. Transmission roller; 11. Common crank; 12. Intermediate connecting rod; 13. Supporting block; 14. Limiting ring; 15. Transmission connecting rod; 16. Thread trimming cam. Detailed implementation mode

[0028] The following are specific embodiments of the present utility model and in combination with the accompanying drawings, the technical solutions of the present utility model will be further described, but the present utility model is not limited to these embodiments.

[0029] Embodiment 1

[0030] As Figure 1 and Figure 2 shown, a driving device of an overlock sewing machine is installed on the machine shell 1 of the overlock sewing machine. The overlock sewing machine includes a thread cutting mechanism 2, a presser foot lifting mechanism 3, a tooth height adjusting mechanism 4 and a stitch length adjusting mechanism 5. Among them, the thread cutting mechanism 2 includes a thread cutting crank, a thread cutting connecting rod, a thread cutting shaft and a thread cutting knife 2a. The thread cutting crank is hinged on the rear side surface of the machine shell 1. The thread cutting shaft is arranged front and back. The thread cutting knife 2a and the thread cutting connecting rod are respectively fixed on the front end and the rear end of the thread cutting shaft. The thread cutting connecting rod is slidably hinged to one end of the thread cutting crank. A thread cutting roller 2b and a forced reset plate are arranged on the other end of the thread cutting crank. A thread cutting reset torsion spring is arranged between the thread cutting crank and the machine shell 1. The thread cutting mechanism 2 can be forced to reset by operating the forced reset plate. The presser foot lifting mechanism 3 includes a presser foot shaft penetrating through the machine shell 1 in the left-right direction. One end of the presser foot shaft is connected with a presser foot arm. A presser foot 3a is fixed on the front end of the presser foot arm. The other end of the presser foot shaft has a presser foot lifting crank, and a presser foot lifting roller 3b is arranged on the presser foot lifting crank.

[0031] A tooth carrier is arranged in the machine shell 1, and a feed dog 4a is fixed on the tooth carrier. The feed dog 4a has teeth for feeding. The tooth height adjusting mechanism 4 includes a tooth adjusting shaft penetrating through the machine shell 1 in the left-right direction. One end of the tooth adjusting shaft is connected with a tooth lifting slider inserted into the tooth carrier. The other end of the tooth adjusting shaft is fixedly connected with a tooth lifting eccentric connecting rod. The tooth height adjusting mechanism 4 further includes a tooth adjusting crank 4b. A long connecting rod is hinged between the tooth adjusting crank 4b and the tooth lifting eccentric connecting rod. Among them, the tooth adjusting crank 4b, the long connecting rod and the tooth lifting eccentric connecting rod are located outside the machine shell 1. The existing structures in the thread cutting mechanism 2, the presser foot lifting mechanism 3 and the tooth height adjusting mechanism 4 can refer to the patent document with the publication number: CN 115852595A.

[0032] The stitch pitch adjusting mechanism 5 includes a feed eccentric wheel assembly 5a and a stitch pitch adjusting transmission assembly. The feed eccentric wheel assembly 5a includes an outer tooth locking ring, an inner tooth locking block, a stitch pitch adjusting wheel, a connecting rod, a feed eccentric wheel, and a stitch pitch adjusting eccentric plate that are sequentially sleeved on the main shaft. Among them, the outer tooth locking ring and the stitch pitch adjusting eccentric plate are fixed on the main shaft. An outer tooth is provided on the outer side surface of the outer tooth locking ring, and an inner tooth capable of meshing with the outer tooth is provided on the inner side surface of the inner tooth locking block. The inner tooth locking block is clamped on the stitch pitch adjusting wheel and can slide along the radial direction of the main shaft on the stitch pitch adjusting wheel. The feed eccentric wheel is sleeved on the stitch pitch adjusting wheel. One end of the connecting rod is sleeved on the eccentric part of the feed eccentric wheel, and the other end of the connecting rod is connected to the feed shaft. The stitch pitch adjusting eccentric plate is fixedly connected to the feed eccentric wheel. The feed eccentric wheel assembly 5a is a conventional structure, and reference can be made to the patent document with the publication number: CN 206545102 U. The stitch pitch adjusting transmission assembly includes a stitch pitch adjusting shaft 5c and a stitch pitch connecting rod 5b that is slidably hinged on the machine housing 1. The stitch pitch adjusting shaft 5c is installed in the machine housing 1 in the left-right direction. One end of the stitch pitch adjusting shaft 5c is fixedly connected with a stitch pitch adjusting crank 5d, and the other end of the stitch pitch adjusting shaft 5c is connected with a stitch pitch adjusting plate 5e. The stitch pitch adjusting plate 5e is provided with an adjusting block that can abut against the inner tooth locking block to disengage the inner tooth from the outer tooth. A strip-shaped hole is formed in the middle of the stitch pitch connecting rod 5b, and an axial position screw is passed through the strip-shaped hole. The axial position screw is fixedly connected with the machine housing 1. The stitch pitch connecting rod 5b can rotate around the axial position screw, and the axial position screw can slide in the strip-shaped hole. The setting of the strip-shaped hole and the axial position screw enables the stitch pitch connecting rod 5b to be slidably hinged on the machine housing 1. The front end of the stitch pitch connecting rod 5b is hinged with the stitch pitch adjusting crank 5d.

[0033] As Figure 1 and Figure 2 shown, the driving device of the overlock sewing machine includes a motor 6 and a transmission shaft 7. The motor 6 can drive the transmission shaft 7 to rotate. The transmission shaft 7 is connected to the tooth height adjusting mechanism 4. The transmission shaft 7 is also fixedly connected with a stitch pitch crank 8 that can abut against and drive the stitch pitch adjusting mechanism 5. During the rotation of the transmission shaft 7, the stitch pitch crank 8 can be separated from the stitch pitch adjusting mechanism 5. Among them, the transmission shaft 7 is fixedly connected with the tooth adjusting crank 4b in the tooth height adjusting mechanism 4. The tooth adjusting crank 4b and the stitch pitch crank 8 are located at the same end of the transmission shaft 7. The stitch pitch connecting rod 5b is perpendicular to the transmission shaft 7. The stitch pitch crank 8 can abut against the rear end of the stitch pitch connecting rod 5b and drive the stitch pitch connecting rod 5b to move. During the rotation of the transmission shaft 7, the stitch pitch crank 8 can be separated from the stitch pitch connecting rod 5b.

[0034] A drive link 15 is hinged to the machine housing 1, and a drive roller 10 is arranged on the drive link 15. A common crank 11 is fixedly connected to the transmission shaft 7, and an intermediate link 12 is hinged between the common crank 11 and the drive link 15. Two support blocks 13 arranged in the left-right direction are fixedly connected to the rear side surface of the machine housing 1. The transmission shaft 7 is arranged through the two support blocks 13, and two limit rings 14 are fixed between the two support blocks 13 on the transmission shaft 7. The two limit rings 14 are respectively in contact with the two support blocks 13. One end of the transmission shaft 7 extends out of one of the support blocks 13 and is sequentially connected to the tooth adjusting crank 4b and the stitch length crank 8, and the other end of the transmission shaft 7 extends out of the other support block 13 and is connected to the common crank 11.

[0035] Such as Figure 3 , Figure 4 and Figure 5As shown, a common cam 9 and a thread cutting cam 16 for driving the thread cutting mechanism 2 are fixedly connected to the rotating shaft 6a of the motor 6. The common cam 9 is provided with a first cam portion 9a for driving the transmission shaft 7 and a second cam portion 9b for driving the presser foot 3a assembly. The contour surface of the first cam portion 9a abuts against the transmission roller 10, and the contour surface of the second cam portion 9b abuts against the presser foot roller 3b. The contour surface of the first cam portion 9a has a first base circle surface 9a1, a first working surface 9a2, a transition surface 9a3, and a first equal-diameter surface 9a4 that are sequentially connected in the circumferential direction. On the contour surface of the first cam portion 9a, the radius of the first base circle surface 9a1 is the smallest, the radius of the first equal-diameter surface 9a4 is the largest, and the radii of the first working surface 9a2 and the transition surface 9a3 both gradually increase in the direction from the first base circle surface 9a1 to the first equal-diameter surface 9a4. The contour surface of the second cam portion 9b has a second base circle surface 9b1, a second working surface 9b2, and a second equal-diameter surface 9b3 that are sequentially connected in the circumferential direction. On the contour surface of the second cam portion 9b, the radius of the second base circle surface 9b1 is the smallest, the radius of the second equal-diameter surface 9b3 is the largest, and the radius of the second working surface 9b2 gradually increases in the direction from the second base circle surface 9b1 to the second equal-diameter surface 9b3. When the first working surface 9a2 acts on the transmission shaft 7, the stitch pitch crank 8 and the stitch pitch adjustment assembly are in a separated state, the second base circle surface 9b1 acts on the presser foot 3a assembly, and the base circle portion of the thread cutting cam 16 acts on the thread cutting assembly; when the first equal-diameter surface 9a4 acts on the transmission shaft 7, the stitch pitch crank 8 and the stitch pitch adjustment assembly are in an abutting state, the second equal-diameter surface 9b3 acts on the presser foot 3a assembly, and the base circle portion of the thread cutting cam 16 acts on the thread cutting assembly; when the thread cutting cam 16 drives the thread cutting assembly to act, the first base circle surface 9a1 acts on the transmission shaft 7 and the second base circle surface 9b1 acts on the presser foot 3a assembly. That is, when the first working surface 9a2 abuts against the transmission roller 10, the stitch pitch crank 8 and the stitch pitch link 5b are in a separated state, the second base circle surface 9b1 abuts against the presser foot roller 3b, and the base circle portion of the thread cutting cam 16 abuts against the thread cutting roller 2b; when the first equal-diameter surface 9a4 abuts against the transmission roller 10, the stitch pitch crank 8 and the stitch pitch link 5b are in an abutting state, the second equal-diameter surface 9b3 abuts against the presser foot roller 3b, and the base circle portion of the thread cutting cam 16 abuts against the thread cutting roller 2b; when the convex portion of the thread cutting cam 16 abuts against the thread cutting roller 2b, the first base circle surface 9a1 abuts against the transmission roller 10, and the second base circle surface 9b1 abuts against the presser foot roller 3b.

[0036] As Figure 3 and Figure 5At the position shown, the base circle part of the thread cutting cam 16 abuts against the thread cutting roller 2b, the first acting surface of the common cam 9 abuts against the driving roller 10, and the second base circle surface 9b1 of the common cam 9 abuts against the presser foot lifting roller 3b. At this time, the teeth of the feed dog 4a are at the set height, and the overlock sewing machine can perform sewing operations. When it is necessary to adjust the height of the teeth of the feed dog 4a during sewing to adapt to the thickness of the sewing material, control the rotation range of the motor 6 so that the first acting surface of the common cam 9 always abuts against the driving roller 10. At this time, the base circle part of the thread cutting cam 16 abuts against the thread cutting roller 2b, the second base circle surface 9b1 of the common cam 9 abuts against the presser foot lifting roller 3b, and the stitch pitch crank 8 and the stitch pitch connecting rod 5b remain separated, that is, the thread cutting mechanism 2, the presser foot lifting mechanism 3, and the stitch pitch adjusting mechanism 5 do not move; clockwise rotation of the motor 6 shaft 6a can raise the teeth of the feed dog 4a, and counterclockwise rotation can lower the teeth of the feed dog 4a. When thread cutting is required after sewing, as Figure 5 At the position shown, the motor 6 shaft 6a rotates clockwise, so that the convex part of the thread cutting cam 16 abuts against the thread cutting roller 2b, the first base circle surface 9a1 of the common cam 9 abuts against the driving roller 10, and the second base circle surface 9b1 of the common cam 9 abuts against the presser foot lifting roller 3b. At this time, the thread cutting mechanism 2 acts to cut the thread, the tooth height adjusting mechanism 4 and the stitch pitch adjusting mechanism 5 do not move, and the presser foot lifting mechanism 3 also does not move; reverse rotation can achieve the reset after thread cutting. When it is necessary to lift the presser foot 3a after sewing, as Figure 5 At the position shown, the motor 6 shaft 6a rotates counterclockwise, the base circle part of the thread cutting cam 16 abuts against the thread cutting roller 2b, the transition surface 9a3 of the common cam 9 abuts against the driving roller 10, and the second working surface 9b2 of the common cam 9 abuts against the presser foot lifting roller 3b. At this time, the presser foot lifting mechanism 3 acts to gradually lift the presser foot 3a, the thread cutting mechanism 2 does not move, the tooth height adjusting mechanism 4 acts to gradually lower the teeth of the feed dog 4a, and the stitch pitch crank 8 and the stitch pitch connecting rod 5b transition from the separated state to the abutting state; reverse rotation can achieve the lowering of the presser foot 3a. When the motor 6 shaft 6a rotates counterclockwise until the second equal-diameter surface 9b3 abuts against the presser foot lifting roller 3b and at the same time the first equal-diameter surface 9a4 abuts against the driving roller 10, at this time the presser foot 3a is lifted to the highest, the teeth are lowered to the lowest, and the stitch pitch adjusting plate 5e in the stitch pitch adjusting assembly abuts against the internal tooth locking block to disengage the internal teeth from the external teeth, that is, the stitch pitch adjusting position is reached, and the stitch pitch can be adjusted by rotating the main shaft of the overlock sewing machine. After the stitch pitch adjustment is completed, reverse rotation makes the first working surface 9a2 of the common cam 9 abut against the driving roller 10 again, so that sewing operations can continue.

[0037] Embodiment 2

[0038] The stitch pitch link 5b is replaced by a slider, and the slider is hinged to the stitch pitch adjusting crank 5d. A chute is provided on the housing 1 of the overlock sewing machine, and the slider is embedded in the chute and can slide. During the rotation of the stitch pitch crank 8, the stitch pitch crank 8 can abut against the slider and drive the slider to slide. Other structures are the same as those in the first embodiment.

[0039] The specific embodiments described herein are merely illustrative of the spirit of the present utility model. Those skilled in the art to which the present utility model pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but they will not deviate from the spirit of the present utility model or exceed the scope defined by the appended claims.

Claims

1. A driving device for an overlock sewing machine, the overlock sewing machine comprising a tooth height adjustment mechanism (4) and a needle distance adjustment mechanism (5), the driving device for the overlock sewing machine comprising a motor (6) and a transmission shaft (7), the motor (6) being capable of driving the transmission shaft (7) to rotate, the transmission shaft (7) being connected to the tooth height adjustment mechanism (4), and characterized in that: The transmission shaft (7) is also fixedly connected to a needle pitch crank (8) capable of abutting against and driving the needle pitch adjustment mechanism (5); the needle pitch crank (8) can be separated from the needle pitch adjustment mechanism (5) during the rotation of the transmission shaft (7); a common cam (9) is fixedly connected to the rotating shaft (6a) of the motor (6); a first cam portion (9a) for driving the transmission shaft (7) is provided on the common cam (9); the contour surface of the first cam portion (9a) comprises a first base circular surface (9a1), a first working surface (9a2), a transition surface (9a3) and a first isodiametric surface which are sequentially connected in the circumferential direction (9a4); on the contour surface of the first cam portion (9a), the radius of the first base circular surface (9a1) is the smallest, the radius of the first equal-diameter surface (9a4) is the largest, and the radius of the first working surface (9a2) and the radius of the transition surface (9a3) both gradually increase in the direction from the first base circular surface (9a1) to the first equal-diameter surface (9a4); when the first working surface (9a2) acts on the transmission shaft (7), the needle pitch crank (8) and the needle pitch adjustment mechanism (5) are in a separated state, and when the first equal-diameter surface (9a4) acts on the transmission shaft (7), the needle pitch crank (8) and the needle pitch adjustment mechanism (5) are in abutment state.

2. The driving device of the overlock sewing machine according to claim 1, characterized in that: The overlock sewing machine further comprises a presser foot lifting mechanism (3); the common cam (9) is further provided with a second cam portion (9b) for driving the presser foot lifting mechanism (3); the contour surface of the second cam portion (9b) comprises a second base circular surface (9b1), a second working surface (9b2) and a second equal-diameter surface (9b3) which are sequentially connected along the circumferential direction; on the contour surface of the second cam portion (9b), the radius of the second base circular surface (9b1) is the smallest, the radius of the second equal-diameter surface (9b3) is the largest, and the radius of the second working surface (9b2) gradually increases in the direction from the second base circular surface (9b1) to the second equal-diameter surface (9b3); when the first working surface (9a2) acts on the transmission shaft (7), the second base circular surface (9b1) acts on the presser foot lifting mechanism (3); and when the first equal-diameter surface (9a4) acts on the transmission shaft (7), the second equal-diameter surface (9b3) acts on the presser foot lifting mechanism (3).

3. The driving device of the overlock sewing machine according to claim 2, characterized in that: The overlock sewing machine also includes a thread trimming mechanism (2), and a thread trimming cam (16) for driving the thread trimming mechanism (2) is fixedly connected to the rotating shaft (6a) of the motor (6); when the thread trimming cam (16) drives the thread trimming mechanism (2) to operate, the first base circular surface (9a1) acts on the transmission shaft (7) and the second base circular surface (9b1) acts on the presser foot lifting mechanism (3).

4. The driving device of the overlock sewing machine according to any one of claims 1 to 3, characterized in that: The needle distance adjustment mechanism (5) comprises a needle distance connecting rod (5b) slidably hinged on the overlock machine housing (1), the needle distance connecting rod (5b) being perpendicular to the transmission shaft (7), and one end of the needle distance connecting rod (5b) being opposite to and able to abut against the needle distance crank (8).

5. The driving device of the overlock sewing machine according to any one of claims 1 to 3, characterized in that: The tooth height adjustment mechanism (4) comprises a tooth adjustment crank (4b) fixedly connected to the transmission shaft (7); the tooth adjustment crank (4b) and the needle distance crank (8) are located at the same end of the transmission shaft (7).

6. The driving device of the overlock sewing machine according to claim 5, characterized in that: A transmission connecting rod (15) is hingedly connected to a casing (1) of the overlock sewing machine, the first cam portion (9a) acts on the transmission connecting rod (15), a common crank (11) is fixedly connected to the transmission shaft (7), and an intermediate connecting rod (12) is hingedly connected between the common crank (11) and the transmission connecting rod (15).

7. The driving device of the overlock sewing machine according to claim 6, characterized in that: Two support blocks (13) are fixedly connected to a casing (1) of an overlock sewing machine, the transmission shaft (7) is passed through the two support blocks (13), one end of the transmission shaft (7) extends out of one of the support blocks (13) and is connected to a tooth adjustment crank (4b) and a stitch length crank (8) in sequence, and the other end of the transmission shaft (7) extends out of the other support block (13) and is connected to a common crank (11).

8. The driving device of the overlock sewing machine according to claim 7, characterized in that: Two limiting rings (14) are fixed on the transmission shaft (7) between the two supporting blocks (13), and the two limiting rings (14) are respectively in contact with the two supporting blocks (13).

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