KR20090039622A - Thread cutting device of sewing machine - Google Patents

Abstract

An apparatus for cutting thread on a sewing machine is provided to cut the looper thread and needle thread after capturing the hung looper thread and needle thread on a needle plate and a looper. An apparatus for cutting thread on a sewing machine including the followings: a thread capturing part(26) capturing needle thread and looper thread on a tip end part(25); a driving knife(30) moving between locations from an advance location; and a fixing knife(31) cutting the needle thread and the looper thread captured by the thread capturing part of the driving knife.

Description

Thread cutting device of sewing machine {THREAD CUTTING DEVICE OF SEWING MACHINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread cutting device of a sewing machine for capturing and cutting a needle thread and a looper thread that spans a needle plate and a looper, and more particularly, to a structure of a movable scalpel provided in a thread cutting device. will be.

Fig. 13 is a partial perspective view showing the thread cutting device 1 of the sewing machine of the prior art. The thread cutting device 1 of the conventional sewing machine is described, for example in Japanese Utility Model Publication No. 63-10149. In this prior art, the looper thread T1 and the needle thread T2, T3 connected to the end of the seam formed in the to-be-sealed material are stretched tightly over the looper 2 from the needle drop hole of the needle plate, and When the seam is formed, the movable scalpel 3 advances in the direction of the arrow A1, and the tension portion T1a and the respective needle threads T2, of the looper thread T1, which are tightly stretched from the needle drop hole to the looper 2. After capturing the tension portions T2a and T2b of T3), they are retracted in the direction of arrow A2, and are pulled to the blade edge portion 4a of the fixed scalpel 4 provided at the retracted retreat position and fixed. In cooperation with the cutting edge 4b formed in the blade edge portion 4a of the scalpel 4, the tension portions T1a; T2a, T2b; T3a, T3b of each thread T1, T2, T3 are configured to be cut. have.

The movable scalpel 3 is a plate-shaped rectangular member in which an upper surface and a lower surface are disposed in parallel with an imaginary plane substantially perpendicular to a movement path of the sewing needles 5 and 6 reciprocating up and down. It faces the needle plate, and the lower surface is disposed facing the looper 2. At one end portion of the movable scalpel 3 on the downstream side in the forward direction A1, a tip portion 7 having a tapered shape toward the downstream side of the forward direction A1 is formed, and the tip portion 7 is formed. Rather, the looper thread engaging recess 8 and the needle thread engaging recess 9 are formed closer to the upstream side of the sewing direction.

When the movable blade 3 moves forward after the sewing operation stops, the distal end portion 7 of the movable blade 3 is each tensioned portion T3a of one needle thread T3 disposed on the most retracted position side. , T3b), and more than the tensioned portion T1a of the looper seal T1, passes upstream of the sewing object upstream, that is, vertically forward to the ground in FIG. The tension portion T1a is guided and captured by the guide surface 10 connected from the tip portion 7 to the transport direction B downstream of the sewing material to the looper thread engagement recess 8. The tension portions T2a and T3a of the needle threads T2 and T3 are guided and captured by the guide surface 10 to the needle thread engagement recess 9, and as described above, By the retraction operation in the direction of arrow A2, the respective tension portions T1a, T2a, T2b; T3a, T3b of all the threads T1, T2, T3 connected to the object to be sewn are moved to the retracted position. Resonate, is cut in cooperation with the fixed volumetric 4.

In the above conventional technique, as described above, the movable scalpel 3 advances in the direction of arrow A1 to capture the tension portion T1a of the looper seal T1, and then retreats in the direction of arrow A2 to retreat to the looper seal T1. When the tensioned portion T1a of) is cut together with each tensioned portion T2a, T2b; T3a, T3b of each needle thread T2, T3, the tensioned portion T1a of the looper thread T1 is a looper. The looper thread T1 can be almost reliably passed between the tension portions T2a and T2b and between the tension portions T3a and T3b of one needle thread T2 wound in a substantially U shape in (2). The tension part T1a of) moves to the conveying direction B upstream of the to-be-encapsulated object rather than the movement path of the front end part 7 because of the vibration and other factors when the movable blade 3 advances in the arrow A1 direction. In the case of one state, a situation arises in which the looper seal T1 is guided into the looper thread engaging recess 8 and cannot be captured. There is a problem that the thread T1 cannot be cut.

An object of the present invention is to provide a thread cutting device of a sewing machine that can reliably cut a looper thread.

The present invention includes a thread capturing portion for capturing a needle thread and a looper thread at a distal end portion, and the thread capturing portion reciprocates between a forward position at which the thread capture portion enters between the needle plate and the looper, and a retracted position withdrawn from the forward position. With operation scalpel,

A fixed scalpel for retracting the needle thread and the looper thread captured by the thread capture portion of the movable scalpel from the tension position at the time of sewing by cooperating with the movable scalpel by moving from the forward position to the retracted position of the movable scalpel. In the thread cutting device of a sewing machine comprising:

The movable scalpel is a thread cutting device for a sewing machine, characterized in that a thread dividing guide for guiding a looper thread to the thread trapping portion is formed in an area closer to the tip side than the thread catching portion.

According to the present invention, when the movable scalpel moves in the forward direction, the tension portion that stretches tightly between the needle plate and the looper of the looper thread is threaded by the thread dividing guide formed on the tip side of the movable trapping thread. By guiding to the capture | acquisition part side and reliably capturing a looper thread by a thread capture part and displacing a movable scalpel to a retracted position, the tensioned part of the captured looper thread can be reliably cut | cooperated with a fixed blade.

Moreover, in this invention, the said thread division guide part is advanced to the forward position from a retreat position on the opposite side to the side in which the said thread capture part is formed with respect to an imaginary plane containing the axis of a movable knife at the front-end | tip of a movable knife. It is preferable to protrude to the downstream side in the direction.

According to the present invention, since the thread dividing guide portion protrudes from the retracted position toward the forward direction downstream from the retracted position, the tension portion of the looper seal is movable due to the vibration of the looper and other factors. Even if it moves to the opposite side of the said thread capture part about the virtual plane which contains the said axis | shaft rather than the tip of a scalpel, the tension part is guided to the thread capture part side about the said virtual plane, and a looper seal is reliably captured and cut | disconnected. can do.

Moreover, in this invention, the said thread division guide part is an upper surface which faces the said needle plate of a movable scalpel in the side in which the said thread capture | acquisition part is formed with respect to the imaginary plane containing the axis of a movable scalpel at the front-end | tip of a movable scalpel. It is preferable to form more indented.

According to the present invention, since the thread dividing guide portion is formed in the front end portion of the movable scalpel at a side where the thread capturing portion is formed with respect to the virtual plane, the tension portion of the looper thread is formed from the front end of the movable scalpel. The thread division guide unit guides the thread trapping unit side to reliably trap and cut the looper thread.

Moreover, in this invention, the said thread division guide part is a surface in the said needle plate of a movable blade on the opposite side to the side in which the said thread capture part is formed with respect to the imaginary plane containing the axis of a movable blade at the front-end | tip of a movable blade. It is preferable that the upper surface is raised and formed.

According to the present invention, since the thread dividing guide portion is formed by being protruded from an upper surface on the side opposite to the side where the thread trapping portion is formed with respect to the virtual one plane, the tension portion of the looper seal is formed in the virtual one plane rather than the tip. In this regard, it is possible to prevent movement to the opposite side of the thread trapping part and guide the thread trapping part side to the thread trapping part side, thereby guiding the tension portion of the looper thread to the thread trapping part side, thereby reliably guiding the looper thread. Can be captured and cut.

As described above, according to the present invention, the tensioned portion of the looper seal moves to the opposite side of the seal trapping portion with respect to an imaginary plane including the axis line rather than the tip of the movable scalpel due to the vibration of the looper and other factors. It can prevent and guide the tension part to the thread capture | acquisition part side with respect to the said imaginary plane, and can reliably capture and cut a looper thread.

The objects, features and advantages of the present invention will become apparent from the following detailed description and drawings.

By using the thread cutting device of the sewing machine according to the present invention, it is possible to reliably cut the looper thread.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 is a partial perspective view showing a thread cutting device 20 of a sewing machine according to an embodiment of the present invention. The thread cutting device 20 of the sewing machine according to the present embodiment is provided below the needle plate bed of the double chain stitch sewing machine or the flat seam stitch sewing machine, and the looper thread T1 at the time of stopping the sewing operation. ) And each tension portion T1a; T2a, T2b; T3a, T3b spanned between the needle dropping holes 22, 23 of the needle plate 21 of each needle thread T2, T3 and the looper 28, At the retracted position where each tension portion T1a connected to the object to be sewn is captured by the looper seal trapping portion 26 and the tension portions T2a and T3a are respectively captured by the needle thread catching portion 27 and retracted from the needle drop position. It is configured to be cut.

The thread cutting device 20 includes a looper thread capturing portion 26 and a needle thread capturing portion 27 for capturing the looper thread T1 and the respective needle threads T2 and T3 on the tip portion 25. Movable scalpels reciprocating in the directions of arrows A1 and A2 between the forward position where these thread trapping portions 26 and 27 entered between the needle plate 21 and the looper 28 and the retracted position withdrawn from this forward position. (30) and the looper thread T1 and each needle thread T2, T3 captured by the thread capture | acquisition part 26, 27 of the movable scalpel 30 with a retreat position from the forward position of the said movable scalpel 30. The fixed knife 31 which retracts from the tension position at the time of sewing by the movement of the arrow A2 direction of a furnace, and cut | cooperate with the said movable scalpel 30 is included.

In the movable scalpel 30 provided in such a thread cutting device 20, a looper seal T1 is located at a tip side of the looper seal trapping section 26, that is, in an area on the downstream side of the arrow A1 direction (left side in FIG. 1). ) Is formed a thread dividing guide portion (32) for guiding the looper thread capture portion (26).

2 is an enlarged plan view showing the vicinity of the distal end portion 34 of the movable scalpel 30, and FIG. 3 is a plan view illustrating the entire movable scalpel 30. The thread dividing guide 32 includes a central axis L1 of the movable scalpel 30 at the distal end portion 34 of the movable scalpel 30 and is perpendicular to the upper or lower surface of the movable scalpel 30. With respect to an imaginary plane perpendicular to the ground of FIG. 2, from the retracted position at a position eccentric to the side opposite to the side where the looper seal trapping portion 26 is formed (ie, the lower side of FIG. 2) by a distance ΔL. It is formed by protruding downstream of the forward direction A1 toward the forward position.

On the movable knife 30, the fixed knife 31 fixed to the base of the sewing machine is laminated, and is not shown in the base end part 35 which protrudes from the fixed knife 31 in the retraction direction A2. The drive lever is connected, and the movable scalpel 30 is displaced and driven in the forward direction A1 and the retraction direction A2 by the drive lever. On the lower surface of the movable scalpel 30, the free end of the thread pressurizing spring 36 is in contact with each other elastically, and the base end of the thread presser spring 36 is fixed to a fixed scalpel mount not shown. By this seal pressing spring 36, the starting end portion of the next seam of the looper seal T1 cut by the movable knife 30 and the fixed knife 31 is held.

4 is an enlarged perspective view of the vicinity of the distal end portion 34 of the movable scalpel 30, and FIG. 5 is a state in which the looper seal T1 is guided to the looper seal capturing portion 26 side by the thread sharing guide portion 32. FIG. It is the rear view which shows. As described above, since the thread dividing guide 32 is formed at the tip side of the looper thread capturing portion 26 of the movable scalpel 30, the movable dividing guide 32 allows the movable scalpel 30. Guides the tensioned portion T1a that is tightly stretched between the needle plate 21 and the looper 28 of the looper thread T1 to the looper thread trapping portion 26 side when the plate moves in the forward direction A1. The looper seal T1 can be captured reliably by the looper seal trapping unit 26. Therefore, when the movable scalpel 30 moves in the direction of arrow A2 and is displaced to the retracted position, the tensioned portion T1a of the looper seal T1 captured by the looper seal trapping portion 26 cooperates with the fixed blade 31. I can cut it surely.

6A, 6B, 7A, 7B, 8A, and 8B are diagrams for explaining the operation of the thread cutting device 20, and Fig. 6A shows that the looper 28 moves to the forward position and the needle thread T2 is shown. , And T3 is captured, and FIG. 6B shows a state immediately after the movable scalpel 30 moves to the forward position to guide the looper seal T1 to the looper seal capture section 26. 7A shows a state in which the looper seal T1 is captured by the looper seal trapping section 26 of the movable scalpel 30 moved to the forward position, and FIG. 7B shows the movable scalpel 30 in the retracting direction ( The state immediately before the cutting which moves to A2) and pulls the looper thread T1 into the retracted position together with the respective needle threads T2 and T3 is shown. 8A shows a state in which the looper thread T1 and the respective needle threads T2 and T3 are cut, and FIG. 8B shows the tensioned portions T2b and T3b of the needle threads T2 and T3 after cutting. The state lifted onto the offering is shown.

When a series of seams are formed, the reciprocating back and forth operation along the directions of arrows A1 and A2 of the looper 28 is stopped, and as shown in FIG. 6A, the movable scalpel 30 is folded back under the fixed scalpel 31. Moving from the position in the forward direction A1, between the substantially U-shaped tension portions T2a and T2b of the respective needle threads T2 and T3 captured by the looper 28 and between the tension portions T3a and T3b. 6B, the tensioned portion T1a of the looper seal T1 is somewhat more upstream of the conveying direction B than the central axis L1 of the movable scalpel 30 (Fig. 6B). Even if 6b is displaced, the thread dividing guide part 32 returns to the upstream side of the said conveying direction B more than the tension part T1a, and it guides to the looper seal trapping part 26 side reliably, FIG. 7A As shown in the drawing, the tension portion T1a is fitted to the looper seal trapping portion 26 to be reliably captured.

The tensioned portion T1a of the looper thread T1 captured in this way is evacuated together with the needle threads T2 and T3 by moving the movable scalpel 30 in the retraction direction A2 as shown in FIG. 7B. After being pulled to the position side and shown in Fig. 8A, after each needle thread T2, T3 is cut, the looper thread T1 is cut, and the starting part of the next seam of the looper thread T1 is the thread. The pressing spring 36 is elastically pressed to the lower surface of the movable scalpel 30, and as shown in Fig. 8B, the tension portions T2b and T3b of each needle thread are pulled onto the object to be sealed. .

Thus, since the said thread division guide part 32 protrudes in the downstream direction of the advance direction A1 at the front-end | tip part of the movable scalpel 30, the looper seal T1 can be captured and cut reliably.

FIG. 9 is a perspective view showing a part of the movable scalpel 30a used in the thread cutting device according to another embodiment of the present invention, and FIG. 10 is a looper thread T1 of the looper thread T1 by the thread dividing guide 32. It is a rear view for demonstrating the state guided to the capture | acquisition part 26 side. In addition, the same code | symbol is attached | subjected to the part corresponding to embodiment mentioned above. In the thread cutting device of the present embodiment, the loop splitting device 32 includes the looper about an imaginary plane in which the thread dividing guide portion 32 includes the central axis L1 of the movable knife 30a at the distal end of the movable knife 30a. It is formed in the side in which the thread capture part 26 is formed rather than the upper surface which faces the said needle plate 21 of the movable scalpel 30a.

Thus, since the thread dividing guide part 32 is formed in the side where the looper seal trapping part 26 is formed about the said one plane, it is recessed rather than the upper surface of the movable scalpel 30a, The tension portion T1a is prevented from moving to the opposite side of the seal trapping portion with respect to an imaginary plane including the axis rather than the tip of the movable scalpel due to the vibration of the looper and other factors, and the tension portion T1a. Can be guided to the thread trapping section 26 with respect to the virtual one plane, and the looper thread can be captured and cut reliably.

FIG. 11 is a perspective view showing a part of the movable scalpel 30b used in the thread cutting device according to another embodiment of the present invention, and FIG. 12 is a looper seal on the thread dividing guide 32 of the movable scalpel 30b. It is a back view for demonstrating the operation | movement T1 is guided. In addition, the same code | symbol is attached | subjected to the part corresponding to embodiment mentioned above. In the thread cutting device of the present embodiment, the looper seal capturing portion 26 is formed with respect to an imaginary plane in which the thread dividing guide portion 32 includes the axis of the movable knife 30b at the distal end of the movable knife 30b. On the side opposite to the side to be formed, it is formed to protrude from the upper surface facing the needle plate 21 of the movable scalpel 30b.

In this way, the thread dividing guide portion is formed by being raised from the upper surface on the side opposite to the side where the looper seal trapping portion is formed with respect to an imaginary plane, so that the tensioned portion T1a of the looper seal T1 is subjected to the vibration of the looper and the like. By the factor, it is prevented from moving to the opposite side of the said thread capture part with respect to the virtual one plane containing the said axis | shaft rather than the front end of a movable scalpel, and the tension part T1a is moved about the said one virtual plane with the yarn capture part ( 26), the looper seal can be captured and cut reliably.

In still another embodiment of the present invention, the front end portion of the movable scalpel protrudes in the forward direction A1 shown in FIGS. 1 to 5, 6A and 6B, 7A and 7B, and 8A and 8B. The first yarn dividing guide 32 and the second yarn dividing guide 32 which is recessed from the upper surface shown in Figs. 9 and 10 may be formed, and Figs. 1 to 5, Figs. 6A and 6B, The first yarn dividing guide portion 32 protruding in the forward direction A1 shown in Figs. 7A and 7B, and Figs. 8A and 8B, and the third yarn dividing from the upper surface shown in Figs. 11 and 12. The guide part 32 may be formed and the 2nd thread division guide part 32 recessed from the upper surface shown in FIG. 9 and FIG. 10, and the 3rd thread division raised from the upper surface shown in FIG. 11 and FIG. The guide part 32 may be formed and the 1st thread division guide part 32 which protruded in the advance direction A1 shown to FIGS. 1-8A and 8B, and FIG. A second thread dividing guide 32 which is recessed from the upper surface shown in Figs. 9 and 10 and a third thread dividing guide 32 raised from the upper surfaces shown in Figs. 11 and 12 may be formed. By appropriately combining these first to third thread dividing guide parts to form at the distal end of the movable scalpel, it is possible to more reliably prevent the loop miss trapped.

The invention can be embodied in many other forms without departing from its spirit or main features. Therefore, the above-described embodiment is merely an example in all respects, and the scope of the present invention is shown in the claims, and is not limited to the specification text at all. In addition, all the variations and changes which belong to a claim are within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is a partial perspective view which shows the thread cutting device of the sewing machine which concerns on one Embodiment of this invention.

Fig. 2 is an enlarged plan view showing the vicinity of the distal end of the movable scalpel.

3 is a plan view showing the entire movable scalpel.

4 is an enlarged perspective view of the vicinity of the distal end of the movable scalpel.

FIG. 5 is a rear view illustrating a state in which the looper seal is guided to the looper seal capturing side by the thread dividing guide portion. FIG.

6A and 6B are views for explaining the operation of the thread cutting device. FIG. 6A shows a state in which the looper moves to the forward position to capture the needle thread, and FIG. 6B shows the movable scalpel moving to the forward position and the looper. The state immediately after guiding a thread to the looper thread capture part side is shown.

7A and 7B are diagrams for explaining the operation of the thread cutting device. Fig. 7A shows a state where the looper seal is captured by the looper seal capturing unit of the movable scalpel moved to the forward position, and Fig. 7B shows the movable scalpel. Shows the state just before the cutting, moving in the retraction direction and pulling the looper thread together with each needle thread to the retracted position.

8A and 8B are diagrams for explaining the operation of the thread cutting device, FIG. 8A shows a state in which the looper thread and each needle thread are cut, and FIG. 8B shows each needle thread after the cutting is pulled onto the workpiece. It shows the true state.

It is a perspective view which shows a part of movable scalpel used for the thread cutting device of the sewing machine which concerns on other embodiment of this invention.

FIG. 10 is a rear view for explaining a state where the looper seal is guided to the looper seal capturing side by the thread dividing guide part. FIG.

It is a perspective view which shows a part of movable scalpel used for the thread cutting device of the sewing machine which concerns on still another embodiment of this invention.

12 is a rear view for explaining an operation in which the looper thread is guided to the thread sharing guide part of the movable scalpel.

It is a partial perspective view which shows the thread cutting device of the sewing machine of a prior art.

 <Explanation of symbols for the main parts of the drawings>

20: thread cutting device

21: needle plate

25: tip

26: looper seal capture

27: needle thread capture

28: Looper

30: movable scalpel

31: fixed scalpel

32: Thread Sharing Guide

T1: looper seal

T2, T3: needle thread

Claims (4)

A thread capturing portion for capturing a needle thread and a looper thread at a distal end, the reciprocating movement between a forward position at which the thread capture portion enters between the needle plate and the looper, and a retracted position retracted from this forward position With operation scalpel to do, A fixed scalpel for retracting the needle thread and the looper thread captured by the thread capture portion of the movable scalpel from the tension position at the time of sewing by cooperating with the movable scalpel by moving from the forward position to the retracted position of the movable scalpel. In the thread cutting device of a sewing machine comprising: The thread cutting device of the sewing machine, characterized in that the movable scalpel is formed with a thread dividing guide portion for guiding the looper thread to the thread trapping portion in an area closer to the tip side than the thread capturing portion. The said thread dividing guide part is advancing toward a forward position from a retreat position on the opposite side to the side in which the said thread capture part is formed with respect to an imaginary plane which contains the axis of a movable knife at the front-end | tip of a movable scalpel. Thread cutting device of a sewing machine, characterized in that formed to protrude in the downstream direction. The said thread dividing guide part faces the said needle plate of a movable scalpel in the side in which the said thread capture part is formed with respect to the virtual plane containing the axis of a movable scalpel at the front-end | tip of a movable scalpel. Thread cutting device of the sewing machine, characterized in that formed in the depression than the upper surface. The said thread dividing guide part is a surface in the said needle plate of a movable scalpel on the opposite side to the side in which the said thread capture | acquisition part is formed with respect to an imaginary plane containing the axis of a movable scalpel at the front-end | tip of a movable scalpel. Thread cutting device of the sewing machine, characterized in that formed by raising from the upper surface.

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