TWM567278U - Structure improvement of thread cutting mechanism of sewing machine - Google Patents

Abstract

The present invention discloses an improvement of a thread cutting mechanism of a sewing machine, which includes: a fixed knife, a wire pressing plate, and a movable knife; the improved part is that the fixed knife and the wire pressing plate are fixedly installed on a fixed knife seat, and the fixed knife seat is installed On the top surface of the hook cylinder, the fixed cutter has a fixed blade portion; the crimping plate is fixedly installed under the fixed knife, and the crimping plate has a tongue; the movable knife includes a movable knife seat and a knife plate that are integrated into one. The knife seat is fixedly mounted on an outer tube shaft. The outer tube shaft is rotatably sleeved on the outside of the rotary hook drive shaft and can reciprocate. The knife plate has a first surface facing the pressure plate, and the first surface has a wire groove. The front end of the guide groove is provided with an opening for guiding the suture into the guide groove through the opening. The end of the guide groove and the first surface have a movable blade portion. The outer tube shaft drives the movable knife to wind around the outside of the rotary hook. The rotary hook is reciprocated between a preparation position and a thread position, in which the tongue of the pressure plate can be inserted into the wire groove and press the suture in the wire groove, and the movable blade is moved during the movement of the knife plate toward the tangent position. Ministry Through the lower edge of the fixed blade portion, the blade portion and the activity by the fixed blade portion synergistic sever the suture.

Description

Improvement of thread trimming mechanism of sewing machine

The invention relates to a thread cutting mechanism of a sewing machine, in particular to an improved thread cutting mechanism having a shorter thread head after cutting a sewing thread, and has the advantages of simple structure, easy maintenance and adjustment.

There are many types of known sewing machines that can be applied to the sewing of different sewn items, one of which is a special sewing machine suitable for sewing shoes, bags or cylinders, which is generally called a cylinder sewing machine.

In the authorized Chinese utility model patent (authorization bulletin number: CN2705480Y), a post-cylinder sewing machine offline holding device is proposed, including: a movable knife, which is fixed on the mounting block mounted on the base with screws, and Its shaft is centered and can be rotated freely, and a blade portion with a curved surface is formed at its end; a fixed knife is mounted on the vertical surface of the soil platform under the rotary hook, and is fixed by screws to move horizontally. It is in contact with the outer peripheral surface of the movable knife. The pressing rod is installed between the fixed knife and the outer peripheral surface of the movable knife. The front end of the rod must be in contact with the groove on the curved surface of the movable knife. The shaft can rotate freely. It is inserted on the socket of the earth platform fixed on the outer periphery of the rotary hook; the stopper is fixed under the shaft of the pressing rod by screws and contacts the notch of the socket installed under the rotary shuttle with space for vertical movement. The upper and lower positions of the pressing rod can be set. A spring is clamped between the stopper and the soil platform; the pressing rod of the spring is used to push the pressing rod to rotate, and its front end is pushed into the bottom surface of the groove of the movable knife.

Please refer to FIG. 1, which shows a conventional automatic thread cutting device of a cylindrical cylinder type sewing machine, in which a fixed knife 10 and a movable knife 11 are installed together on a knife holder 12, and the knife holder 12 is fixedly installed on the top surface of the rotary cylinder 13 14, where the position of the fixed knife 10 relative to the knife seat 12 is fixed, the movable knife 11 is installed on a movable knife holder 15 that can be reciprocated, the movable knife holder 15 has a rotating shaft 151, and the bottom end of the rotating shaft 151 has an engaging tooth 152, The meshing tooth 152 meshes with a driving gear 16 mounted on the rotary cylinder 13, and the reciprocating driving gear 16 drives the movable knife holder 15 and the movable knife 11 to reciprocate between a preparation position and an all-line position, and then is fixed by The coordinated operation of the knife 10 and the movable knife 11 completes the automatic thread trimming operation.

In the authorized new Taiwan patent (Certificate No .: M531960), an automatic thread cutting device similar to the technology shown in Figure 1 is proposed, which includes: all knife mechanisms with a fixed cutter and a movable cutter, and The movable cutter is connected to all the cutter shafts, and the cutter shaft is equipped with a gear; a swing mechanism has a rotating shaft forming a swing center, and the rotating shaft is provided with a first swing arm and a second swing arm. The arm is formed with a pressed arm and an abutment arm, and the second swing arm is formed with a driving tooth that keeps meshing with the gear and can drive the cutter shaft to deflect; a cam is assembled on the lower shaft of the sewing machine, And rotates synchronously with the lower shaft, and the cam is located on the side of the abutting arm, and is provided with a deflection curved surface; a driver has a mandrel that is movable and retractable toward the pressure arm, and the mandrel can push against the pressure The arm further drives the swinging mechanism to synchronously deflect in a forward direction, so that the abutting arm contacts the cam, and the cam deflection curved surface will again push against the abutting arm and advance. The above-mentioned swing mechanism is driven to synchronously perform a swing in a return direction to complete the thread cutting operation.

The movable knife and the fixed knife of the aforementioned prior art thread-cutting mechanism are both mounted on the rotary cylinder. The rotation axis of the movable knife of Fig. 1 and M531960 is located on the rotary axis of the rotary hook. On one side, the size of the rotary hook cylinder in the radial direction of the rotary hook becomes larger. The structure of the pressing rod used to clamp the suture is complicated, and its manufacture and assembly are not easy. In addition, the engaging teeth 152 and The driving gear 16 is apt to generate noise when rotating, and is easy to produce errors due to wear after a period of use, and the assembly and replacement of parts are relatively inconvenient.

The thread trimming mechanism of the cylinder sewing machine proposed in the authorized Taiwanese new patent (certificate number: M522964) includes: a fixed knife and a movable knife. The difference from the previous known technology is that the fixed knife of the M522964 patented technology is It is fixedly installed on the inner bottom surface of the needle plate. Although this design can avoid the increase of the size of the hook cylinder in the radial direction of the rotary hook, the design of fixing the fixed knife to the inner bottom surface of the needle plate needs to redesign and manufacture the needle. Plate, it will increase the manufacturing cost, and the assembly, adjustment and maintenance of the fixed knife are relatively inconvenient.

Please refer to Figure 2. In the authorized Taiwanese new patent (Certificate No .: M535233), another thread-cutting device for a column sewing machine is proposed, which is mainly composed of a cutter set, a transmission, and a lower shaft. The cutter set The fixed cutter 18 is located behind the pinhole 171 of the pinhole plate 17, and the movable cutter 19 of the cutter group is assembled on the side seat, wherein the transmission device is assembled on the movable cutter 19 and can drive the movable cutter from The hook thread position on the side of the pinhole 171 is swung around a rotation axis parallel to the lower axis to a cutting position where the suture is cut.

One of the objects of the present invention is to solve the above-mentioned problems of the conventional sewing machine, and to provide an improved sewing machine thread cutting mechanism with a simple structure and easy maintenance and adjustment.

An improved embodiment of the thread trimming mechanism of the novel sewing machine includes: a fixed knife, a pressure plate and a movable knife; the improved part is that the fixed knife and the pressure plate are fixedly installed in a fixed knife holder, and the fixed knife The seat is fixedly installed on the top surface of the hook cylinder. A fixed blade part; a crimping plate is fixedly installed below the fixed knife, and the crimping plate has a tongue piece; the movable knife comprises a movable knife seat and a knife plate integrated into one, and the movable knife seat is fixedly mounted on an outer tube shaft, the outer tube The shaft is rotatably sleeved on the outside of the rotary hook transmission shaft and can reciprocate. The blade plate has a first surface facing the crimping plate, the first surface has a wire groove, and the front end of the wire groove has an opening for guiding the slit. The thread enters the guide groove through the opening. The end of the guide groove and the first surface have a movable blade. The outer tube shaft drives the blade of the movable knife around the rotary hook in a prepared position and at all thread positions. Reciprocating rotation, in which the tongue of the crimping plate can extend into the wire groove and press the suture in the wire groove. During the movement of the blade toward the tangent position, the movable blade passes the lower edge of the fixed blade. The movable blade portion and the fixed blade portion cooperate to cut the suture.

In a modified embodiment of the thread cutting mechanism of the novel sewing machine, the fixed blade has an inclined surface extending obliquely toward the first surface, and the fixed blade portion is located at an end of the inclined surface in the oblique extending direction.

In an improved embodiment of the thread trimming mechanism of the novel sewing machine, the tongue of the pressure-clamping plate extends obliquely toward the wire groove of the movable knife, and the tongue can first press the seam in the wire groove before cutting the suture. line.

In an improved embodiment of the thread trimming mechanism of the novel sewing machine, the movable knife seat of the movable knife has a first jacket, and the first jacket is screwed with a first adjusting bolt for clamping the first jacket to the outside. Tube shaft.

The advantage of the new model is that the movable knife seat of the movable knife is directly installed on the outer tube shaft, and there is no abrasion problem of gears and meshing teeth meshing with each other. The new movable knife can be directly installed on the existing sewing machine shown in Figure 1, without the need of The design and structure of the existing sewing machine can be greatly changed, and the existing sewing machine shown in Fig. 1 can be easily upgraded, and it has simple assembly and maintenance. Simple and convenient effect; on the other hand, the new type of fixed knife and crimping board are fixedly mounted on a fixed knife seat, the fixed knife seat is installed on the top surface of the rotary cylinder barrel, the assembly of the fixed knife and the wire plate, It is easy to adjust and maintain, and there is no need to redesign and manufacture the needle plate.

The specific embodiments of the present invention and other advantages and effects will be described below with reference to the drawings.

[Learning technology]

10‧‧‧ fixed knife

11‧‧‧ movable knife

12‧‧‧Blade holder

13‧‧‧ Hook

14‧‧‧Top

15‧‧‧ movable knife rest

151‧‧‧Shaft

152‧‧‧ meshing teeth

16‧‧‧Drive gear

17‧‧‧ pinhole plate

171‧‧‧ pinhole

18‧‧‧ fixed cutter

19‧‧‧ movable cutter

[This new model]

20‧‧‧ Hook Shuttle Barrel

201‧‧‧Top

21‧‧‧ Hook

22‧‧‧ Hook shuttle shaft

23‧‧‧Second Gear

24‧‧‧ Spindle

25‧‧‧ first gear mesh

30‧‧‧ Needle plate

31‧‧‧ Needle plate cylinder

40‧‧‧ fixed knife

41‧‧‧Fixed knife holder

42‧‧‧ Bolt

43‧‧‧Fixed blade

44‧‧‧ Bolt

45‧‧‧ bevel

50‧‧‧Pressure plate

51‧‧‧ tongue

60‧‧‧ movable knife

61‧‧‧ movable knife holder

62‧‧‧Blade

63‧‧‧first surface

64‧‧‧conductor groove

641‧‧‧perforation

65‧‧‧ opening

66‧‧‧Activity Blade

67‧‧‧Outer tube shaft

68‧‧‧The first jacket

681‧‧‧The first adjustment bolt

69‧‧‧Second jacket

691‧‧‧Second adjustment bolt

70‧‧‧feeding mechanism

71‧‧‧Feeding wheel

72‧‧‧ connecting rod

Fig. 1 is a tangential structure view of a conventional cylinder-type sewing machine.

Fig. 2 is a structural view of a thread cutting device of another conventional column type sewing machine.

FIG. 3 is a structural diagram of an embodiment of an improved thread cutting mechanism of the novel sewing machine, showing the structure of the thread cutting mechanism and other related mechanisms.

FIG. 4 is a partial structural diagram of an improved embodiment of the thread cutting mechanism of the novel sewing machine, showing the exploded structure of the fixed knife.

FIG. 5 is a partial structural diagram of an embodiment of an improved thread cutting mechanism of the novel sewing machine, showing the structure of a movable knife.

FIG. 6A is an operation schematic diagram of an embodiment of an improved thread cutting mechanism of the novel sewing machine, showing a situation where the movable knife is in a preparation position.

FIG. 6B is an operation schematic diagram of an embodiment of an improved thread cutting mechanism of the novel sewing machine, and illustrates the situation where the movable knife is at the thread cutting position.

The positional relationships described in the following embodiments include: up, down, left, and right. Unless otherwise specified, they are based on the directions of components shown in the drawings.

First, please refer to FIG. 3, which is a structural diagram of an improved embodiment of the thread cutting mechanism of the new sewing machine, and illustrates the structure of the thread cutting mechanism and other related mechanisms.

The thread cutting mechanism proposed by the present invention is installed on the hook cylinder 20 and below the needle plate 30. The hook cylinder 20 is basically provided with a hook 21 and a hook transmission shaft 22 for driving the hook 21 to rotate. A second gear 23 is mounted at the bottom end of the shuttle transmission shaft 22, and the second gear 23 can mesh with a first gear 25 mounted on a main shaft 24. The main shaft 24 is a power unit of the sewing machine (generally a motor, not shown in the figure). ) Driven, the main shaft 24 drives the rotary hook 21 to rotate through the first gear 25 and the second gear 23. The position of the hook 21 is higher than the top surface 201 of the hook cylinder 20. The position of the hook 21 is lower than the needle plate 30. The needle plate 30 of the sewing machine is installed on the top of the needle plate cylinder 31 and is located on the needle. Below (not shown), the needles installed in the head of the sewing machine reciprocate up and down through the perforations on the needle plate 30, the upper thread pulled by the needles and the lower thread of the rotary hook 21 interact to realize the car Sewing operation of the seam. The hook cylinder 20 and the needle plate cylinder 31 can be combined to form the cylinder part of the sewing machine. The cylinder part is installed on the base of the sewing machine. Because the design of the conventional sewing machine is the same, the appearance of the complete sewing machine is not shown. The base of the needle plate cylinder 31 is equipped with a feeding mechanism 70. The feeding wheel 71 of the feeding mechanism 70 is located on the side of the needle. The top of the feeding wheel 71 is exposed outside the top surface of the needle plate 30 for sewing operations. Move the sewing material among them.

An improved embodiment of the thread trimming mechanism of the novel sewing machine includes a fixed knife 40, a thread clamp 50, and a movable knife 60. The improved part is that the fixed knife 40 and the thread clamp 50 are fixedly mounted on one The fixed blade holder 41 is, for example, a fixed blade 40 and a crimping plate 50 fixed to the fixed blade holder 41 with bolts 44.

Referring to FIG. 4, the fixed knife holder 41 is fixedly installed on the top surface 201 of the rotary cylinder barrel 20. For example, the fixed knife holder 41 is fixedly installed on the top surface 201 of the rotary cylinder barrel 20 with bolts 42 and fixed. The knife 40 has a fixed blade portion 43 that bulges from the edge of the fixed blade holder 41. The crimping plate 50 is fixedly installed below the fixed blade 40. The crimping plate 50 is shorter than the fixed blade 40 and the crimping plate. 50 has a tongue piece 51.

Referring to FIG. 5, the movable knife 60 includes a movable knife holder 61 and a knife plate 62 integrated into one body. The movable knife holder 61 is fixedly mounted on an outer tube shaft 67. One embodiment is the movable knife holder 61 of the movable knife 60. There is a first jacket 68, and the first jacket 68 is screwed with a first adjusting bolt 681 for clamping the first jacket 68 to the outer tube shaft 67. The outer tube shaft 67 is a tubular element, and the outer tube shaft 67 is rotatably sleeved on the outside of the rotary hook transmission shaft 22 and can be reciprocated. In other words, the outer tube shaft 67 and the rotary hook transmission shaft 22 can rotate independently without interfering with each other; the blade plate 62 has a A first surface 63, the first surface 63 has a wire groove 64, the front end of the wire groove 64 has an opening 65 for guiding the suture from the opening 65 into the wire groove 64, and the shape of the opening 65 is a wide front and a narrow rear The trumpet shape can use the opening 65 to guide the suture through the opening 65 into the lead groove 64 when the thread cutting operation is performed. The end of the lead groove 64 and the first surface 63 have a movable blade portion 66. One of the embodiments is in the lead A hole 641 is opened at the end of the groove 64, and the edge of the hole 641 is used. The position where the edge meets the first surface 63 forms the movable blade portion 66; the outer tube shaft 67 drives the blade plate 62 of the movable knife 60 on the outside of the hook 21 around the hook 21 in a prepared position (see FIG. 6A). ) And all positions (see FIG. 6B), in which the first surface 63 of the blade 62 can pass below the fixed blade portion 43 and is close to the fixed blade portion 43. Therefore, the blade 62 faces the tangent position During the movement, the movable blade portion 66 passes through the lower edge of the fixed blade portion 43, and the suture is cut by the movable blade portion 66 and the fixed blade portion 43 in cooperation.

Preferably, the fixed blade 40 has an inclined surface 45 extending obliquely toward the direction of the first surface 63, and the fixed blade portion 43 is located at an end of the inclined surface 45 in the obliquely extending direction.

The tongue piece 51 of the crimping plate 50 can protrude into the wire groove 64 and press the suture in the wire groove 64. During the movement of the knife plate 62 toward the tangent position, the movable blade portion 66 passes the lower edge of the fixed blade portion 43, The movable blade portion 66 and the fixed blade portion 43 cooperate to cut the suture. Preferably, the tongue piece 51 of the crimping plate 50 extends obliquely toward the direction of the guide groove 64 of the movable knife 60. Before cutting the suture, the tongue piece 51 can first press the suture in the guide groove 64 to avoid sewing. The line is offset or loose.

In an improved embodiment of the thread trimming mechanism of the novel sewing machine, a second clamp 69 is installed at the bottom end of the outer tube shaft 67, and the second clamp can be clamped by a second adjusting bolt 691 screwed to the second clamp 69. The sleeve 69 is clamped to the bottom end of the outer tube shaft 67. The outer tube shaft 67 is connected to the connecting rod 72 of the movable knife driving mechanism (not shown) through the second clamping sleeve 69. The linear reciprocating motion further drives the outer tube shaft 67 to reciprocate, so that the blade 62 of the movable knife 60 can be driven outside the rotary hook 21 in the preparation position (see FIG. 6A) and the tangent position (see section 6A). (Figure 6B).

By adjusting the position of the second sleeve clamp 69 on the outer tube shaft 67, the starting point and end point of the reciprocating rotation of the outer tube shaft 67 can be adjusted, and the preparation position and tangent position of the blade plate 62 of the movable knife 60 can be adjusted.

Although the new model has been disclosed as above through the above-mentioned embodiments, it is not intended to limit the new model. Any person skilled in similar arts can make some changes and retouches without departing from the spirit and scope of the new model. The scope of patent protection shall be subject to the definition in the claims attached to this specification.

Claims (4)

An improved thread trimming mechanism of a sewing machine is provided. The thread trimming mechanism is installed on a rotary cylinder barrel and is located below a needle plate. The rotary cylinder barrel is provided with a rotary hook and a rotary hook drive shaft for driving the rotary hook. The thread cutting mechanism includes: a fixed knife, a wire pressing plate, and a movable knife, which are characterized in that: the fixed knife and the wire pressing plate are fixedly installed in a fixed knife seat, and the fixed knife seat is fixedly installed in the hook cylinder. The top surface of the fixed knife has a fixed blade portion; the wire pressing plate is fixedly installed below the fixed knife, the wire pressing plate has a tongue piece; the movable knife comprises a movable knife seat and a knife plate integrated into one, The movable knife seat is fixedly mounted on an outer pipe shaft, the outer pipe shaft is rotatably sleeved on the outer side of the rotary hook drive shaft and can be reciprocated, and the knife plate has a first surface facing the wire pressing plate. One surface has a wire groove, and the front end of the wire groove has an opening for guiding a suture through the opening to enter the wire groove. An end of the wire groove and the first surface have a movable blade portion, and the outer tube. The shaft drives the movable tool holder and the The plate rotates back and forth around the rotary hook between a prepared position and a thread position on the outside of the rotary hook, wherein the tongue of the wire pressing plate can extend into the wire groove and press the wire groove in the wire groove. For the suture, the movable blade portion passes the lower edge of the fixed blade portion during the movement of the blade toward the tangent position, and the movable blade portion and the fixed blade portion cooperate to cut the suture. The thread trimming mechanism of the sewing machine according to claim 1 is improved, wherein the fixed blade has an inclined surface extending obliquely toward the first surface, and the fixed blade portion is located at an end of the inclined surface in the obliquely extending direction. As described in claim 1, the thread trimming mechanism of the sewing machine is improved, wherein the tongue of the pressure plate extends obliquely toward the direction of the wire groove of the movable knife, and the tongue can be pressed before cutting the suture. The suture in the guide groove. The thread cutting mechanism of the sewing machine according to claim 1 is improved, wherein the movable knife seat of the movable knife has a first jacket, and the first jacket is screwed with a first adjusting bolt for clamping the first jacket. On the outer tube shaft.