CN212152660U - Short thread trimming mechanism and sewing machine - Google Patents

Abstract

The utility model provides a short thread trimming mechanism and a sewing machine. The short thread trimming mechanism comprises a first movable knife and a second movable knife that can move toward each other and can be engaged, and a lifting component. The first movable knife and the second movable knife The knives are arranged below the needle plate in the sewing machine, and the elevating part acts on the first movable knife and the second movable knife to shorten the distance between the engagement position of the first movable knife and the second movable knife and the upper surface of the needle board . The elevating part in the present application makes the engagement position of the first movable knife and the second movable knife closer to the upper surface of the needle plate in the up-down direction, so the length of the thread remaining on the sewing material can be shortened after the thread trimming is completed. To achieve the effect of trimming short thread ends, avoid manual secondary trimming of thread ends, thereby improving sewing efficiency and meeting the needs of high-end sewing.

Description

Short thread trimming mechanism and sewing machine

technical field

The utility model relates to a short thread trimming mechanism.

The utility model also relates to a sewing machine comprising the above short thread trimming mechanism.

Background technique

At present, all sewing machines are equipped with a thread trimming mechanism, which is used to cut the upper thread and the lower thread at the end of sewing, thereby realizing automatic thread trimming. The thread trimming methods of the thread trimming mechanism usually have two types: rotary thread trimming and horizontal thread trimming, and the thread trimming mechanism of the rotary thread trimming mechanism has two types: double-acting knife thread trimming mechanism and single-acting knife thread trimming mechanism, such as: application An automatic thread trimming mechanism for a sewing machine disclosed in Chinese invention patent application with publication number CN106894175A is a single-acting knife thread trimming mechanism. However, when the existing thread trimming mechanism is trimming the thread, the occlusal position of the two movable knives in the double-acting knife thread trimming mechanism, or the occlusal position of the movable knife and the fixed knife in the single-acting knife thread trimming mechanism are all farther from the needle plate. The needle drop hole is far away, which leads to a longer thread length remaining on the sewing material after thread trimming. After automatic thread trimming, manual trimming of the longer thread ends is still required, which cannot meet the needs of high-end sewing and reduces the efficiency.

Utility model content

In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a stub thread trimming mechanism, which can realize the thread trimming effect of the stub thread.

In order to achieve the above purpose, the utility model provides a short thread trimming mechanism, which includes a first movable knife and a second movable knife that can move toward each other and can be engaged, and a lifting component, the first movable knife and the second movable knife. The knives are all arranged below the needle plate in the sewing machine, and the elevating member acts on the first movable knife and the second movable knife to shorten the gap between the engagement position of the first movable knife and the second movable knife and the upper surface of the needle board the distance.

Further, the short thread trimming mechanism also includes a first knife rest and a second knife rest rotatably installed in the bottom of the sewing machine, and a lower bushing fixed in the bottom of the sewing machine, the bottom bushing is used for supporting In the lower shaft of the sewing machine, the first movable knife is fixed to the first knife rest, and the second movable knife is fixed to the second knife rest; the lower shaft sleeve includes a first shaft section and a second shaft section eccentrically arranged , both the second tool rest and the second tool rest are rotatably mounted on the outer circumference of the first shaft segment, and the first shaft segment of the lower shaft sleeve constitutes the elevating member; when the first movable knife and When the second movable knife is engaged, the central axis of the outer peripheral surface of the first shaft segment is higher than the central axis of the outer peripheral surface of the second shaft segment.

Further, the short thread trimming mechanism also includes a first knife rest and a second knife rest that are both rotatably installed in the bottom plate of the sewing machine, the first movable knife is fixed to the first knife rest, and the second movable knife is fixed to the first knife rest. The knife is fixed on the second knife rest; the elevating component includes a first gasket fixed between the first movable knife and the first knife rest, and a first gasket fixed between the second movable knife and the second knife rest Second gasket.

Further, the short thread trimming mechanism further includes a thread trimming drive assembly, and the thread trimmer drive assembly is connected between the lower shaft of the sewing machine and the first knife rest and the second knife rest.

Further, the wire-cutting transmission assembly includes a crank shaft, a first wire-cutting crank, a second wire-cutting crank, a wire-cutting connecting rod, and a transmission pin fixed to the second tool holder, and the crank shaft is parallel to the lower shaft , and driven to rotate by the lower shaft, one end of the first trimming crank is fixed on the crank shaft, the other end of the first trimming crank, one end of the second trimming crank, and one end of the trimming connecting rod are connected to each other. Fixed, the other end of the thread trimming link is hinged with the first tool rest, the other end of the second thread trimming crank is rotatably mounted on the crank shaft, and is provided with a chute for sliding engagement with the transmission pin.

Further, an escape groove is formed on the lower surface of the needle plate, and the escape groove is upwardly concave in a direction away from the first movable knife and the second movable knife.

Further, the needle plate is provided with a needle drop hole that penetrates up and down, and the engagement position of the first movable knife and the second movable knife is located just below the needle drop hole.

The utility model also provides a sewing machine, wherein the sewing machine is equipped with the above-mentioned short thread trimming mechanism.

As mentioned above, the short thread trimming mechanism and the sewing machine involved in the present utility model have the following beneficial effects:

In the present application, the elevating member makes the engagement position of the first movable knife and the second movable knife closer to the upper surface of the needle plate in the up-down direction, so that the length of the thread remaining on the sewing material can be shortened after the thread trimming is completed. To achieve the effect of trimming short thread ends, avoid manual secondary trimming of thread ends, thereby improving sewing efficiency and meeting the needs of high-end sewing.

Description of drawings

FIG. 1 is a schematic structural diagram of the short thread trimmer mechanism in the application.

FIG. 2 is a schematic view of the partial structure of FIG. 1 at the needle drop hole of the needle plate.

FIG. 3 is a partial structural schematic diagram of the remaining thread ends after the thread trimming mechanism of the short thread trimming mechanism in the application.

FIG. 4 is a schematic structural diagram of the thread trimming drive assembly in the application.

FIG. 5 is a schematic structural diagram of the lower bushing in the present application.

FIG. 6 is a schematic diagram of the connection of the first movable knife and the first knife holder in the application.

FIG. 7 is a schematic diagram of the connection between the second movable knife and the second knife rest in the application.

FIG. 8 is a schematic diagram of the structure of the needle plate in the application.

FIG. 9 is a flow chart of the work of the sewing machine in the application when the thread is trimmed.

Component label description

1 first moving knife

2 Second moving knife

3-pin plate

31 Avoidance slot

32 pin hole

4 Bottom plate

5 First tool holder

6 Second tool holder

7 Lower bushing

71 First shaft segment

72 Second shaft segment

8 Lower shaft

9 First gasket

10 Second gasket

11 Crankshaft

12 First trimming crank

13 Second trimmer crank

131 Chute

14 Thread trimmer link

15 Drive pin

16 needles

17 sewing material

18 noodles

19 Bottom Line

Detailed ways

The embodiments of the present invention are described below by specific embodiments, and those who are familiar with the technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

It should be noted that the structures, proportions, sizes, etc. drawn in the accompanying drawings of this specification are only used to cooperate with the contents disclosed in the specification for the understanding and reading of those who are familiar with this technology, and are not used to limit the conditions for the implementation of the present invention. , so it does not have technical substantive significance, any modification of the structure, the change of the proportional relationship or the adjustment of the size, without affecting the effect that the present utility model can produce and the purpose that can be achieved, should still fall within the present utility model. The disclosed technical content can cover the scope. At the same time, terms such as "up", "down", "left", "right", "middle", etc. quoted in this specification are only for the convenience of description and clarity, and are not used to limit the implementation of the present invention. The change or adjustment of the scope and its relative relationship shall also be regarded as the applicable scope of the present invention without substantially changing the technical content.

The utility model provides a sewing machine, which is equipped with the above short thread trimming mechanism. For ease of description, in the following embodiments, the definitions of each direction are as follows: As shown in Figure 1, the axial direction of the lower shaft 8 in the sewing machine is defined as the left-right direction, and the direction of the lower shaft 8 toward the sewing machine head is the left direction, The direction of the lower shaft 8 toward the tail of the sewing machine is the right direction; the moving direction of the sewing material 17 when the sewing machine is sewing is defined as the forward direction; the direction orthogonal to the left-right direction and the front-rear direction is defined as the up-down direction.

Figure 1 is a left side view of the sewing machine in the application; as shown in Figure 1, the sewing machine involved in the application includes a base plate 4, a needle plate 3 fixed on the base plate 4, a needle 16 capable of up and down reciprocating motion, and a short thread trimmer Thread mechanism, the needle plate 3 is provided with a needle drop hole 32 that penetrates up and down and allows the needle 16 to pass up and down, as shown in Figure 8; and the second movable knife 2 and the elevating part, the first movable knife 1 and the second movable knife 2 are both arranged below the needle plate 3 in the sewing machine, and the elevating part acts on the first movable knife 1 and the second movable knife 2 , Used to shorten the distance between the engagement position of the first movable knife 1 and the second movable knife 2 and the upper surface of the needle plate 3 .

When the sewing machine is sewing, as shown in Figures 1 to 3, the sewing material 17 is pressed against the needle plate 3 by the presser foot in the sewing machine, and moves forward under the action of the feed dog in the sewing machine, and the needle 16 moves up and down, The needle 16 carries the upper thread 18 to pierce the sewing material 17, and cooperates with the rotary hook in the sewing machine for providing the lower thread 19 to complete the sewing. At the end of sewing, the first movable knife 1 and the second movable knife 2 in the short thread trimming mechanism move toward each other until they are engaged, so as to cut the upper thread 18 and the lower thread 19 . In particular, when trimming the thread, the elevating member makes the engagement position of the first movable knife 1 and the second movable knife 2 closer to the upper surface of the needle plate 3, so that the residual on the sewing material 17 can be shortened after the thread trimming is completed. The length of the thread head can be adjusted to achieve the trimming effect of the short thread head, avoiding the manual secondary trimming of the thread head, thereby improving the sewing efficiency and meeting the needs of high-end sewing.

Preferably, the engagement position of the first movable knife 1 and the second movable knife 2 is located just below the needle drop hole 32 , that is, the engagement position of the first movable knife 1 and the second movable knife 2 is located at the center axis of the needle drop hole 32 . In combination with the elevating part, the distance between the occlusal position of the first movable knife 1 and the second movable knife 2 and the upper surface of the needle plate 3 is minimized, so as to minimize the length of the thread after trimming and realize one trimming. The thread end on the reverse side of the back sewing material 17 is shorter, so as to achieve the effect of thread trimming that improves the sewing quality and does not require manual trimming of the thread end.

Further, as shown in FIG. 1 and FIG. 4 , the short thread trimming mechanism also includes a first knife rest 5 and a second knife rest 6 rotatably installed in the sewing machine base 4 , and a lower knife fixed in the sewing machine base 4 . The shaft sleeve 7 and the thread trimming drive assembly; the lower shaft sleeve 7 is used to support the lower shaft 8 in the sewing machine; the first movable knife 1 is fixed to the first knife rest 5, and the second movable knife 2 is fixed to the second knife rest 6; The thread trimming drive assembly is connected between the lower shaft 8 of the sewing machine and the first knife rest 5 and the second knife rest 6. When the thread is trimmed, the lower shaft 8 rotates, and the first knife rest 5 and the second knife rest are driven by the thread trimming drive assembly. The tool rest 6 rotates around the lower shaft sleeve 7, and then drives the first movable knife 1 and the second movable knife 2 to rotate around the lower shaft sleeve 7; therefore, in this application, the movement of the first movable knife 1 and the second movable knife 2 The way is to rotate around the lower bushing 7 .

Further, as shown in FIGS. 1 and 4 , the thread trimming transmission assembly includes a crankshaft 11 , a first thread trimming crank 12 , a second thread trimming crank 13 , a thread trimming connecting rod 14 , and a The drive pin 15 and the crank shaft 11 are rotatably installed in the bottom plate 4, the crank shaft 11 is parallel to the lower shaft 8 and is driven to rotate by the lower shaft 8, the upper end of the first trimming crank 12 is fixed on the left end of the crank shaft 11, The lower end of the first thread trimming crank 12, the lower end of the second thread trimming crank 13, and the front end of the thread trimming link 14 are fixed by a left and right extending tightening screw. A tool rest 5 is hinged by an axial screw extending left and right, the upper end of the second thread trimming crank 13 is rotatably mounted on the left end of the middle crank shaft 11, the second thread trimming crank 13 is located on the left side of the first thread trimming crank 12, In addition, the rear section of the upper end of the second trimming crank 13 is provided with a sliding groove 131 which is slidably matched with the transmission pin 15 . The connection structure between the lower shaft 8 and the crank shaft 11 is in the prior art, and reference may be made to an automatic thread trimming mechanism for a sewing machine disclosed in Chinese Invention Patent Application Publication No. CN106894175A, which will not be described here. During thread trimming, there is power transmission between the lower shaft 8 and the crank shaft 11, the lower shaft 8 drives the crank shaft 11 to rotate, the crank shaft 11 drives the first thread trimming crank 12 to rotate together, and the first thread trimming crank 12 passes through the thread trimming connecting rod. 14. Drive the first tool rest 5 to rotate around the lower bushing 7, and at the same time, the first trimming crank 12 also drives the second tool rest 6 to rotate around the lower hub 7 through the second trimming crank 13 and the transmission pin 15. The rotation directions of the frame 5 and the second blade frame 6 are opposite, thereby realizing the relative movement of the first movable blade 1 and the second movable blade 2 .

Further, the elevating member has the following two embodiments.

The first embodiment of the lifting component, as shown in FIG. 5 , the lower shaft sleeve 7 includes a first shaft segment 71 , and a second shaft segment 72 located on the right side of the first shaft segment 71 , the first shaft segment 71 and the second shaft segment 72 both extend left and right, and the two are eccentrically arranged. The supporting hole in the lower shaft sleeve 7 that is matched with the lower shaft 8 passes through the first shaft segment 71 and the second shaft segment 72 left and right, and the second shaft segment 72 is rotatably installed on the sewing machine. in bottom plate 4. The elevating component is the first shaft segment 71 of the lower bushing 7; when the first movable knife 1 and the second movable knife 2 are engaged and the lines are trimmed, in the vertical direction, the central axis of the outer peripheral surface of the first shaft segment 71 is high On the central axis of the outer peripheral surface of the second shaft segment 72, both the second tool rest 6 and the second tool rest 6 are rotatably mounted on the outer periphery of the first shaft segment 71, and the first tool rest 5 is raised through the first shaft segment 71. and the position of the second knife rest 6, that is, the position of the first movable knife 1 and the second movable knife 2 is raised, thereby shortening the gap between the engagement position of the first movable knife 1 and the second movable knife 2 and the needle plate 3. distance, the first movable knife 1 and the second movable knife 2 can engage and trim the thread at the position closest to the upper surface of the needle plate 3 to ensure the shortest residual thread on the sewing material 17 when the thread is trimmed. In this embodiment, when the lower bushing 7 is fixed with the bottom plate 3, the eccentric position is installed on it in the vertical direction to ensure that when the first moving knife 1 and the second moving knife 2 rotate around the lower bushing 7 for tangent, the first moving The knife 1 and the second movable knife 2 just move to the highest eccentric point of the first shaft segment 71 of the lower sleeve 7 , so as to achieve the shortest distance from the upper surface of the needle plate 3 .

The second embodiment of the elevating member, as shown in Figures 6 and 7, the elevating member includes a first gasket 9 fixed between the first movable knife 1 and the first knife rest 5, and a first gasket 9 fixed between the second movable knife 1 and the first knife rest 5. The second spacer 10 between the knife 2 and the second knife rest 6, the first spacer 9 raises the position of the first movable knife 1, and the second spacer 10 raises the position of the second movable knife 2, thereby shortening the The distance between the engagement position of the first movable knife 1 and the second movable knife 2 and the needle plate 3, the first movable knife 1 and the second movable knife 2 can be engaged at the position closest to the upper surface of the needle plate 3 during thread trimming Trim the thread to ensure the shortest remaining thread on the sewing material 17. In the views shown in FIGS. 6 and 7 , the first gasket 9 and the first tool holder 5 are of separate structures, and the second gasket 10 and the second tool holder 6 are also of separate structures, while in other embodiments , the first gasket 9 and the first tool rest 5 can be an integral structure, and the second gasket 10 and the second tool rest 6 are also of an integrated structure, that is, the first gasket 9 can be upward on the first tool rest 5 As for the raised portion extending integrally, the second gasket 10 may be a raised portion integrally extending upward on the second tool rest 6 .

Preferably, as shown in FIG. 8 , under the condition that the overall strength and thickness of the needle plate 3 remain unchanged, the lower surfaces of the needle plate 3 facing the first movable knife 1 and the second movable knife 2 are partially provided with escape grooves 31 . , the avoidance groove 31 is concave upwards in the direction away from the first movable knife 1 and the second movable knife 2 to avoid interference, such as avoiding contact with the screws that fix the first movable knife 1, the first washer 9 and the first knife holder 5 Interference is generated to avoid interference with the screws for fixing the second movable knife 2 , the second washer 10 and the second tool holder 6 .

The sewing machine with the above structure works as follows when trimming the thread: as shown in FIG. After receiving the thread trimming command, the controller of the sewing machine controls the stitch length to be reduced from the current stitch length value to a small stitch length value of 0.3~1mm or -0.3~-1mm, and after the sewing machine sets the number of stitches, the controller will Send a command to the thread trimmer drive source, and set the number of sewing stitches to be pre-stored in the controller. The actuation of the thread trimmer drive source makes the power transmission between the lower shaft 8 and the crank shaft 11, and controls the feeding mechanism of the sewing machine to feed the material in the opposite direction to the original feeding direction, that is, if the sewing is performed with a small stitch length, the number of stitches to be sewn is set. If it is forward stitching when the thread is trimmed, it is reverse stitching when the thread is trimmed; if it is reverse stitching when the number of stitches is set for small stitch sewing, it is forward stitching when the thread is trimmed. The lower shaft 8 drives the crank shaft 11 to rotate, and drives the first moving knife through the first trimming crank 12 , the trimming connecting rod 14 , the first knife rest 5 , the second trimming crank 13 , the transmission pin 15 and the second knife rest 6 The upper thread 18 and the lower thread 19 are cut by 1 and the second movable knife 2 rotating around the lower bushing 7 in opposite directions. Through this working method, the upper thread 18 and the lower thread 19 can be in a symmetrical state with respect to the tangent position at the moment when the upper thread 18 and the lower thread 19 are cut, so that the thread ends of the upper thread 18 and the lower thread 19 are as short as possible, and the neat and beautiful thread ends after thread trimming are ensured. No need for manual trimming, improve work efficiency, reduce labor costs, and meet high-end sewing requirements.

To sum up, the utility model effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims (8)

1. A short thread trimming mechanism, comprising a first movable knife (1) and a second movable knife (2) that can move toward each other and can bite, the first movable knife (1) and the second movable knife (2) ) are arranged below the needle plate (3) in the sewing machine, and it is characterized in that: it also includes an elevating part, and the elevating part acts on the first movable knife (1) and the second movable knife (2) to shorten the The distance between the engagement position of the first movable knife (1) and the second movable knife (2) and the upper surface of the needle plate (3). 2. The short thread trimming mechanism according to claim 1 is characterized in that: it also comprises the first knife rest (5) and the second knife rest (6), which are all rotatably installed in the sewing machine base plate (4), and a lower shaft sleeve (7) fixed in the bottom plate (4) of the sewing machine, the lower shaft sleeve (7) is used to support the lower shaft (8) in the sewing machine, and the first movable knife (1) is fixed on the first movable knife (1) The tool holder (5), the second movable knife (2) is fixed on the second tool holder (6); the lower shaft sleeve (7) comprises an eccentrically arranged first shaft segment (71) and a second shaft segment ( 72), both the second tool rest (6) and the second tool rest (6) are rotatably mounted on the outer circumference of the first shaft segment (71), and the first shaft segment ( 71) forming the elevating member; when the first movable knife (1) and the second movable knife (2) are engaged, the central axis of the outer peripheral surface of the first shaft segment (71) is higher than the second shaft segment (72) The central axis of the outer peripheral surface. 3. The short thread trimming mechanism according to claim 1 is characterized in that: it also comprises the first knife rest (5) and the second knife rest (6) which are both rotatably installed in the sewing machine base plate (4), The first movable knife (1) is fixed on the first knife rest (5), and the second movable knife (2) is fixed on the second knife rest (6); A first gasket (9) between the knife (1) and the first knife rest (5), and a second gasket (9) fixed between the second movable knife (2) and the second knife rest (6) 10). 4. The short thread end thread trimming mechanism according to claim 2 or 3, characterized in that: further comprising a thread trimming drive assembly, the thread trimming drive assembly is connected to the lower shaft (8) of the sewing machine, and the first knife rest ( 5) and the second tool holder (6). 5. The stub thread trimming mechanism according to claim 4, wherein the thread trimming transmission assembly comprises a crank shaft (11), a first thread trimming crank (12), a second thread trimming crank (13), A thread trimming connecting rod (14) and a transmission pin (15) fixed on the second tool rest (6), the crank shaft (11) is parallel to the lower shaft (8) and is driven to rotate by the lower shaft (8) , one end of the first trimming crank (12) is fixed on the crank shaft (11), the other end of the first trimming crank (12), one end of the second trimming crank (13), and the trimmer One end of the connecting rod (14) is fixed, the other end of the thread trimming connecting rod (14) is hinged with the first tool rest (5), and the other end of the second thread trimming crank (13) is rotatably mounted on the The crankshaft (11) is provided with a chute (131) slidingly matched with the transmission pin (15). 6 . The short thread trimming mechanism according to claim 1 , wherein an escape groove ( 31 ) is formed on the lower surface of the needle plate ( 3 ), and the escape groove ( 31 ) moves away from the first movement. 7 . The directions of the knife (1) and the second movable knife (2) are concave upward. 7 . The short thread trimming mechanism according to claim 1 , wherein the needle plate ( 3 ) is provided with a needle drop hole ( 32 ) that penetrates up and down, and the first movable knife ( 1 ) and the first movable knife ( 1 ) and the second The occlusal position of the two movable knives (2) is located just below the needle drop hole (32). 8. A sewing machine, characterized in that: the sewing machine is equipped with the short thread trimming mechanism according to any one of claims 1-7.

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