JPH02114992A - Thread cutting device - Google Patents

Abstract

PURPOSE:To enable thread to be cut off so that lower thread to be attached to and left on the side of cloth may be extremely shortened, by permitting the cutting edge tips of a pair of cutter elements to meet with each other at a position close to a needle plate and under a needle slot. CONSTITUTION:Sewing comes to an end, and the working of a needle 8 and a shuttle 4 is stopped, and in the mean-time, by a driving mechanism 21, cutter elements 11, 12 and a lower thread leading segment 17 are worked. In other words, when a driving lever 24 is moved as shown in an arrow head, then the respective members 11, 12, 17 are respectively moved as shown in arrow heads A, C, and the lower thread leading segment 17 crosses the lower section of a needle slot 2a, and lower thread 42 is led out of the shuttle 4. After that, the respective cutting edge tips of cutting edges 11a, 12a on the front side in the moving direction of the cutter elements 11, 12 meet with each other at a position close to a needle plate 2 and under the needle slot 2a, and the lower thread 42 is cut off. In this manner, cutting-off is performed, and so lower thread 42a connected to cloth 40, among the lower thread 42 is extremely shortened. Besides, lower thread 42b on the side of the shuttle 4, among the lower thread 42 is led previously out of the lower thread leading segment 17, and so the thread 42b is left to be long.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thread cutting device for cutting a lower thread or an upper thread in a sewing machine.

[Conventional technology]

Under the throat plate, a fixed side force cover element is disposed at a lateral position avoiding the position below the needle hole from which the needle descends, and the fixed side force cover element is disposed at a position below the needle hole where the needle descends. There is a thread cutting device comprising a movable cutter element adapted to move towards the element.

[Problem to be solved by the invention]

In this conventional thread cutting device of a sewing machine, the thread is cut at positions unevenly distributed laterally from below the needle hole, so there is a problem that a long thread remains attached to the right side after cutting. There is a problem in that such long threads require troublesome work such as cutting with scissors in a subsequent process.

The present invention has been made in view of the above points, and its purpose is to cut the thread of a sewing machine so that the bobbin thread that remains attached to the right side is extremely short. The purpose is to provide equipment.

[Means to solve problems]

In order to achieve the above object, the present invention takes the measures as described in the claims above, and its effects are as follows.

[Effect]

When cutting the thread, the cutting edges of the pair of cutter elements meet at a position near the throat plate and below the needle hole to cut the thread. Therefore, the length of the thread remaining on the right side is extremely short.

〔Example〕

The drawings showing the embodiments of the present application will be described below.

In FIG. 1, numerals 1 to 9 indicate the constituent members of a well-known multi-spindle sewing machine (for example, the same as that shown in Japanese Patent Application Laid-Open No. 60-173156), where 1 is a bed and 2 is a throat plate. , 3 is a shaft for driving the hook, 4 is a hook, 5 is an arm disposed above the bed 1, 6 is a holder attached to the arm 5 so as to be horizontally rotatable, 7 is attached to the holder 6 On the other hand, the needle bar is movable up and down, 8 is the needle, 9 is the presser foot, 10
shows a thread cutting device provided under the throat plate 2.

Next, the thread cutting device [10] will be explained in detail based on FIG. 2.3. Reference numerals 11 and 12 designate a pair of cutter elements, which are pivotally connected to the lower surface side of the needle vi2 using a pivot shaft 13.

Each cutter element 11.12 has a respective blade 11a, 11b and 12a, 12b. 14 is Namiwansha,
By pressing the cutter element 12 against the cutter element 11, it is possible to improve the mutual rubbing of the blades in the double force vine element. 15 and 16 indicate driven pieces attached to each cutter element; 17 indicates a pair of cutter elements 11;
．． A lower thread pull-out piece 21 disposed below the thread cutter element 12, which is formed integrally with the cutter element 12 in this example, represents a drive mechanism in the thread cutting device 10. Reference numeral 22 denotes a base frame of the drive mechanism, also called a mounting base, which is fixed to the bed 1. A drive shaft 23 is rotatably mounted on the base frame 22, and a drive lever 24 is fixed to the upper end. The drive lever 24 is provided with engagement holes 25 and 26, which are illustrated as drive parts,
Each of the driven pieces 15, 16 is engaged with the driven pieces 15,16. 27
28 is a transmission lever attached to the lower end of the drive shaft 23, and 28 is a drive device for swinging the transmission lever 27 in the direction of the arrow. For example, a solenoid is used (an air or hydraulic cylinder may also be used).

Next, 31 indicates an upper thread distribution mechanism, and 32 is a mounting frame for this mechanism, which is fixed to the bend 1. 33 is the mounting frame 3
For example, a rotary solenoid having a drive shaft 33a that rotates back and forth is used. Reference numeral 34 denotes an upper thread hanging piece, which is formed in a forked shape, and its base is connected to the drive shaft 33a using a mounting bracket 35, so that it can be moved in and out of the hook 4.

Next, cutting of the lower thread and upper thread by the thread cutting device r1110 will be explained based on the time chart of FIG. 9 and the operation diagrams of FIGS. 4 to 8. In Figs. 4 to 8, (A) is a plan view, (B) is a longitudinal cross-sectional view of the cloth, needle plate, and thread cutting device cut away at the B-R position in Fig. 4 (A), (C), 4A is a vertical cross-sectional view of the cloth, throat plate, and thread cutting device taken along the line C-C in FIG. 4(A). Further, FIGS. 4 to 8 show the states at each point in time indicated by symbols 1 to 2 in FIG. 9, respectively.

In the process (a) in FIG. 9, as is well known, the needle 8 moves up and down, the hook 4 rotates, and the cloth 40 is moved laterally by the cloth feed device (cloth drive east) 40a in FIG. Sewing and embroidery on cloth 40 using upper thread 41 and lower thread 42 are performed in a well-known manner. At this time, the cutter elements 11, 12 and the bobbin thread pull-out piece 17 in the thread cutting device 10 are in a ready state as shown in FIG.

Next, when the above-mentioned sewing is finished and the point shown in FIG. It is operated as follows. First, when the drive lever 24 moves as shown by the arrow in FIG. crosses under the needle hole 2a, and the bobbin thread 42 is pulled out from the hook 4 as shown in FIGS. 5(^) and (C). Next, the cutting edges of the front blades 11a and 12a of the cutter element 11.12 in the moving direction are aligned at a position close to the throat plate 2 and below the needle hole 2a, as shown in FIG. 5(C). , cut the lower thread 42.

Because the cutting is performed in this way, the lower thread 42a on the side of the lower thread 42 that connects to the cloth 40 is very short (for example, 5fi).
Of the bobbin threads 42, the bobbin thread 42b on the hook 4 side is left long (for example, 60n) because it has been pulled out in advance by the bobbin thread pull-out piece 17. In addition, the cut lower thread 42b on the lid side
is swept away by the bobbin thread pull-out piece 17 and becomes suspended from the axle 4a as shown by the imaginary line in FIG. 5(C).

After the lower thread is cut as described above, the upper thread is then cut as follows. Continuing the operation of the drive mechanism 21 moves the cutter elements 11, 12 from the states of FIGS. 5(A) and 6(C) to the states of FIGS. 6(A) and 6(A), respectively.
As shown in (C), it is laterally moved beyond the bottom of the needle hole 2a. Further, the drive device 33 in the upper thread distribution mechanism 31 is operated, and the upper thread hooking piece 34 is moved to the hook 4 as shown in FIG.
invade inside. In this state, the operation of hook 4 and total 8 of the sewing machine is restarted, and the process shown in FIG. 9(c) is performed.

During this process, the needle 8 through which the upper thread 41 is threaded enters the hook 4, as shown in FIG. As is well known, the needle thread 41 is hooked on the tip of the hook 4 and goes around the hook 4, thereby forming a loop as well known. Eventually, the needle 8 rises to the top dead center and is shown in Figure 9 (d).
When this point is reached, the operation of the hook 4 and needle 8 in the sewing machine is stopped. In this state, the loop 41d of the upper thread 41 is caught on the upper thread hooking piece 34, as shown in FIG.

After this state is reached, the drive mechanism 21 in the thread cutting device 10 is operated to return, and the cutter element 11.12 moves in the return direction as shown by the arrow in FIGS. 7(A) and 7(C). . During the movement process, each cutter element H,1
As shown in FIG. 8, the cutting edges of the rear blades 11b and 12b in 2 are aligned under the needle hole 2a, and the needle thread 41 located under the needle hole 2a is connected to the cloth 40. Cut the needle thread 41a on the side where it is present. In this case, since the upper thread 41a is cut below the needle hole 2a, the upper thread 41C remaining on the cloth 40 side is extremely short as in the case of the lower thread described above.

After the needle thread 41 has been cut in the manner described above, the cutter elements 11, 12 are returned to the ready position as shown in FIG. 4 by the drive mechanism 21, which operates continuously. Also, needle thread hanging piece 3
4 is also evacuated outside the pot.

The operations of the needle, hook, and thread cutting device as described above are performed in conjunction with each other using, for example, a well-known sequence control technique.

Next, BLLs that operate differently in the above embodiment will be explained. When the lower thread 42 is cut by the force element 11.12, only the lower thread 42 is present below the needle hole 2a (the upper thread 4
1 or needle 8 does not exist).
The process may be performed at any time within the period indicated by the symbol (al) in FIG.

In addition, the needle thread hanging piece 34 needs only to enter the hook 4 before the loop 41d of the needle thread 41 formed by the rotation of the hook 4 comes out of the hook 4, as shown in FIG. It may be performed at any time within the period indicated by symbol 伽.

Furthermore, the cutting of the upper thread 41 by Fugetsu 11b and 12b
This can be done when the needle thread connected to 0 is located below the needle hole 2a, and for this purpose, without using the needle thread distributing mechanism 31 as described above, At the point indicated, the needle thread loop 41 as shown in FIG.
The upper thread 41 is connected to the cloth in the process where d passes under the hook 4.
The upper thread 41a may be cut at the time when the upper thread 41b connected to the upper thread 41a is separated from the upper thread 41b.

Furthermore, if it is not necessary to cut the upper thread, the cutter element 11.12 can be returned to the ready position of FIG. 4A immediately after cutting the lower thread 42, as shown in FIG. It's okay.

Next, different embodiments of the present application will be described. In FIG. 1, reference numerals 51 and 52 indicate a first holding mechanism and a second holding mechanism which are additionally provided in the above-mentioned sewing machine, both of which are known in the above-mentioned publication. Reference numeral 51 holds the upper thread 41 between a well-known thread take-up and a total 8 in the sewing machine, and the second holding mechanism 52 has a thread pulling finger piece 52a that can move forward and backward in the direction of the arrow. The needle thread 41b on the needle 8 side after being cut can be drawn into the holding frame 53.

Next, the operation of cutting the lower thread and upper thread when the first and second holding mechanisms 51 and 52 as described above are provided will be explained using the time chart of FIG. 11.

First, the cutting of the bobbin thread 42 after the sewing is completed is carried out in the same manner as in the previous embodiment.

After the bobbin thread is cut and the operation of the hook and needle is resumed as described above, the needle 8 is lowered and raised once in step (c), and the upper thread finger piece 34 is moved as described above. After the loop 41d of the upper thread is formed, a known needle skipping mechanism attached to the needle bar 7 is operated to keep the needle at the top dead center as shown in (e) and move the needle to another hook. The operation of the balance continues.

In this process (E), at the time point shown in (F), the first holding mechanism is operated to hold the needle thread 41 between the thread take-up and the needle 8, and its movement is prevented. Next, the thread pulling finger piece 52a in the second holding mechanism is moved as shown in FIG.
B) The needle is moved forward downwards as shown in (C). Next, at point (g), after the operations of the hook and the thread take-up are stopped, the cutter elements 11, 12 are returned to their original positions in the same way as in the case described above, and the upper thread 41a connected to the cloth is cut. In this case, since the needle thread 41a is held by the first holding mechanism 51 so as not to move (do not loosen), cutting by the cutter elements 11 and 12 is reliably performed. After the cutting, the thread pulling fingers 52a of the second holding mechanism 52 move backward toward the thread holding frame 53, and as shown by the imaginary lines in FIG. The cloth 40 is pulled out and pulled into the holding frame 53, thereby completely freeing the cloth 40 not only from the lower thread but also from the upper thread 41.

Next, in step (h), when the sewing operation of the sewing machine is restarted, the upper thread 41 is released from being held by the first holding mechanism 51, and sewing on the cloth as is well known is performed. The upper thread 41 is held by the first holding mechanism 51 until the needle thread 41 threaded through the needle 8 is no longer likely to be pulled out from the needle after the above-mentioned sewing is resumed due to the lifting of the thread take-up or the thread take-up spring. This will continue, and the hold will be released after that possibility has disappeared.

Next, the upper thread may be held by the first holding mechanism 51 when the upper thread is held taut by the thread take-up (or may be performed before or after the above-mentioned point (f)).

In addition, the needle thread may be cut when the needle thread connected to the fabric is located below the needle hole and the gauge is above the needle hole, and may be cut before or after the point (g) above. Also good.

Next, FIGS. 12 and 13 show examples of different configurations of the thread cutting device. In this example, the bobbin thread pull-out piece 17
e is formed separately from the cutter elements 11e and 12e, and is provided with an independent driven piece 55.

In the drive lever 24e, the cutter elements 11e, 1.
2e and the bobbin thread pull-out piece 17e, respectively, are formed in the form of one long engagement hole 56, into which the driven pieces 15e, 16e, 55 are engaged.

In the above structure, when the drive lever 24e is in the ready position, the cutter elements 11e, 12e and the bobbin thread pull-out piece 1
7e is in the ready position as shown in FIG. 13(A). When the drive lever 24e moves in the direction of the arrow from this state, each cutter element
12g and the bobbin thread pull-out piece 17a move in the directions of the arrows, respectively, to form the shape M (cutter element 1) shown by the solid line in FIG.
The blades 11ae and 12ae of 1e and 12e meet to cut the bobbin thread), and then move to the position shown by the imaginary line in the figure. Next, when the drive lever 246 is operated to return, the cutter elements 11e, 12e and the lower thread pull-out piece 17e move in the return direction, cutting the upper thread in the process, as shown in FIG. 13(A).
Return to state.

When the cutter element lie, 128 and the lower thread pull-out piece 17e move as described above, each driven piece 15e moves from the pivot 13e.

15e and 55 are different, and the engagement hole 5
Since the engagement position of each driven piece with respect to 6 is different,
Each of the cutter elements 11e, 12e and the lower thread pull-out piece 17e operate at different swing angles.

An example of those angles is shown in Table 1.

Table 1 In the structure as described above, the bobbin thread pulling piece moves with a movement width larger than that of the cutter element 12e, so even if the movement width of the cutter element is small, the bobbin thread remaining on the lid side can be removed more easily. It can be made longer, and the entanglement with the needle thread at the start of the next sewing can be ensured.

It should be noted that parts that are considered to have the same or equivalent structure as those in the previous figure in terms of function are given the same reference numerals as in the previous figure with the letter e, and redundant explanations are omitted.

〔Effect of the invention〕

As described above, in the present invention, after sewing is completed, the cloth 4 is cut by operating the pair of cutter elements 11 and 12.
Not only does it have the effect of cutting the bobbin thread 42 that is connected to the needle thread 42, but when cutting the bobbin thread 42, the cutting edges of the cutter elements 11. 12 and the hook 4, the bobbin thread is pulled out from the hook 4 in advance by the bobbin thread pull-out piece 17, so that the bobbin thread 4 on the hook 4 side
2b can be left long, which has the effect of smoothing the entanglement with the upper thread 41 at the start of the next sewing, and at the same time, the bobbin thread 42a remaining on the fabric 40 side can be shortened and used in the subsequent process of fabric 40. This has the effect of eliminating the need to organize unnecessary bobbin threads.

Furthermore, in the present invention, when the force lid element is provided with blades 11a, llb, 12a, and 12b on the front and rear sides, respectively, after cutting the bobbin thread 42, the cutter element 11. 12, the upper thread 41 connected to the cloth 40 can also be cut, and there is an advantage that preparations for cutting the next lower thread and cutting of the upper thread 41 can be done at the same time.

Moreover, since the needle thread 41 is cut at a position close to the throat plate 2 and below the needle hole 2a, the needle thread 41c remaining on the cloth 40 side can be shortened as in the case of the bobbin thread. This has the effect of eliminating the need for needle thread arrangement in the subsequent process.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a vertical sectional view of the main parts of an embroidery sewing machine, FIG. 2 is a partially cutaway perspective view showing a thread cutting device installed in the bed of the sewing machine, and FIG. An exploded perspective view of the thread cutting device, FIGS. 4 to 8 are operation explanatory diagrams, FIG. 9 is a time chart, FIG. 10 is a vertical cross-sectional view showing the distribution of the upper thread, and FIG. 11 is a different implementation. FIG. 12 is an exploded perspective view showing a different embodiment of the thread cutting device, and FIG. 13 is a plan view for explaining the operation of the thread cutting device shown in FIG. 12. 2... Throat plate, 2a... Needle hole, 4... Hook, 1112
... cutter element, 17 ... bobbin thread pull-out piece, 40 ... cloth, 41 ... needle thread, 42 ... bobbin thread. Diagram? Figure 2 Figure (C) Figure (C) Figure 12 Figure X ＼

Claims (1)

[Claims] 1. A needle plate having a needle hole through which a needle moves up and down and a hook disposed below the needle plate cut the thread by matching the cutting edges of each other. In the sewing machine thread cutting device equipped with a pair of cutter elements as described above, each of the cutter elements is movable toward the bottom of the needle hole provided in the throat plate, and furthermore, A matching point is determined so that the cutting edges meet at a position near the throat plate and below the needle hole, and a matching point is established between the pair of cutter elements and the shuttle before the cutting edges match. A sewing machine thread cutting device equipped with a bobbin thread pull-out piece that runs across the bottom. 2. Between the throat plate, which has a needle hole through which the needle moves up and down, and the shuttle located below, there is a pair of cutters that cut the thread by matching their blade edges. In the thread cutting device for a sewing machine, each of the cutter elements is movable toward the bottom of the needle hole provided in the throat plate, and the cutting edges of each cutter element are located close to the throat plate. A matching point is defined to meet at the position and below the needle hole, and the cutter element has blades on the front side and the rear side, respectively, in the direction of movement below the needle hole, and The cutter elements are configured to be movable beyond the needle hole, and the cutter elements are configured to move back under the needle hole when the needle thread connected to the fabric is located below the needle hole. The thread cutting device of the sewing machine is linked to the movement of the needle so that the cutting edge of each of the rear blades coincides with the needle hole at a position close to the needle plate in the returning process. 3. The thread cutting device for a sewing machine according to claim 1, wherein the lower thread pulling piece is connected to the cutter element so as to move in a movement width larger than that of the cutter element. 4. The thread cutting device for a sewing machine according to claim 2, further comprising a holding mechanism configured to prevent the upper thread from loosening when the cutting edges of the rear blades of the pair of cutter elements coincide with each other.