JPH04354979A - Decorative thread cutting device for sewing machine with plural needles - Google Patents

Abstract

PURPOSE:To perform assured cutting by engaging and drawing a decorative thread closer by a movable cutting knife without fail, regardless of the thickness of a cloth, at the end of sewing, even when adjustment of the moving path of the movable cutting knife is roughly done. CONSTITUTION:A movable cutting knife 17 of a cutting knife mechanism is project-moved in such a manner that a hook part 17a at the tip of the movable cutting knife 17 would advance to an intermediate part of an upper side decorative thread part 5A, which is extended approximately horizontally between a thread engaging part 3a of a decorative thread looper 3 and a decorative thread path guide 4, to engage the intermediate part of the upper side decorative thread part 5A, and the upper decorative thread part 5A is drawn obliquely back upward and cut.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to, for example, a flat three-needle sewing machine or a flat two-needle sewing machine. This invention relates to a decorative thread cutting device for a multi-needle sewing machine.

0002

[Prior Art] This type of sewing machine is conventionally known to be configured so that when a foot pedal is operated at the end of sewing, the sewing machine stops operating and the needle thread and looper thread are automatically and mechanically cut. It is.

[0003] Further, a device in which the decorative thread is mechanically gripped and pulled out at the end of sewing and automatically cut through a knife mechanism is disclosed in, for example, Japanese Patent Publication No. 11635/1983. The conventional example will be briefly explained below.

That is, a decorative thread cutting knife mechanism consisting of a movable knife and a fixed knife is equipped, and at the end of sewing, the movable knife of this female mechanism is used to cut the decorative thread from diagonally backward and above with respect to the reciprocating plane of the decorative thread looper. The thread looper is moved near the middle of the lower decorative thread stretched between the thread hooking part and the sewing end part, and the lower decorative thread is hooked with the hook at the tip of the movable knife. The movable knife is configured to move diagonally rearward and upward to pull the hooked decorative thread and cut it by shearing action between the movable knife and the fixed knife.

[0005]

[Problem to be Solved by the Invention] According to the conventional decorative thread cutting device configured as described above, it is possible to automatically cut the decorative thread at the end of sewing in the same way as the needle thread and looper thread, It is possible to improve the efficiency of the sewing work as a whole, including the cutting of decorative threads, without having to take much time to cut the threads.

However, in the above-mentioned conventional device, the movable knife in the knife mechanism enters the decorative thread portion formed by the decorative thread looper into a substantially triangular shape in plan view, and the movable knife in the female mechanism enters the decorative thread portion which is formed in a substantially triangular shape in plan view. Since the side decorative thread is hooked on the hook, in order to ensure that the thread is hooked without mistakes, the moving path of the movable scalpel should be adjusted according to the thickness and material of the fabric. It is troublesome that settings must be made with extremely high precision each time in response to various sewing conditions such as thread material and needle width.

In particular, when sewing thick fabrics, the length of the lower decorative thread hooked by the hook at the tip of the movable knife is shortened, so that the movable knife enters and closes as described above.
Even if the exit movement path is adjusted with high accuracy prior to sewing, thread hooking errors tend to occur, and it is difficult to ensure that the thread is cut in a predetermined manner.

The present invention has been made in view of the above circumstances, and even if the movement path of the movable scalpel is roughly adjusted, the decorative thread can always be hooked without mistakes, regardless of the thickness of the fabric. It is an object of the present invention to provide a decorative thread cutting device for a multi-needle sewing machine that can perform precise cutting.

[0009]

[Means for Solving the Problems] In order to achieve the above object, a decorative thread cutting device for a multi-needle sewing machine according to the present invention is provided with a decorative thread looper and a surface for reciprocating the decorative thread looper at the end of sewing. A movable knife enters from diagonally rearward and upward, hooks the decorative thread on the tip hook, and moves diagonally rearward and upward. A decorative thread cutting device for a multi-needle sewing machine is provided with a female mechanism for cutting decorative threads consisting of a fixed knife that cuts the decorative threads between said female mechanism, and said movable knife of said female mechanism is connected to said female mechanism so that said tip hook part is said to be The decorative thread looper is moved so as to advance into the middle part of the upper decorative thread part stretched between the thread hooking part and the decorative thread path guide, and the middle part of the upper decorative thread part is hooked. It is configured to be pulled diagonally rearward and upward for cutting.

Further, it is preferable that a recessed portion is formed near the tip of the decorative thread looper at the inner periphery corresponding to the moving path of the movable knife in and out when stopping at the end of sewing.

[0011]

[Operation] According to the above structure, at the end of sewing, the movable knife of the knife mechanism enters and moves diagonally from behind and above the plane for reciprocating the decorative thread looper. Due to this thrusting movement, the tip hook of the movable knife advances to the middle part of the upper decorative thread section stretched between the thread hooking section of the looper and the decorative thread guide, and returns diagonally backward and upward again. At this time, the upper decorative thread section is hooked by the tip hook of the movable knife and pulled diagonally backward and upward, and the decorative thread is cut by the shearing action between the movable knife and the fixed knife.

[0012] By the way, the upper decorative thread part stretched between the thread hooking part of the looper and the decorative thread guide is in a substantially horizontal position, and there is no space between it and the upper surface of the fabric in the vertical direction. Not only is there a sufficiently large clearance, but the length is also longer than the lower decorative thread section stretched between the thread hooking section of the decorative thread looper and the sewing end section. Therefore,
To ensure the cutting of decorative threads without causing mistakes in thread hooking regardless of the thickness of the fabric.

In particular, when stopping at the end of sewing, if a recess is formed in the inner periphery of the decorative thread looper corresponding to the entry/exit movement path of the movable knife, the movable knife can be brought closer to the above-mentioned upper decorative thread. This makes it possible to move the decorative thread in and out, making it possible to cut the decorative thread even more reliably.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view of the main parts of a flat three-needle sewing machine, which is an example of a multi-needle sewing machine, and Fig. 2 is an enlarged perspective view of the thread row. supply. Reference numeral 3 designates a decorative thread looper, and as shown in FIG. 5, at its tip end there is a thread hooking part 3a for catching the decorative thread 5 supplied from above via the thread guide 4 and guiding it diagonally downward. At the same time, a recessed portion 3b is formed at a location corresponding to an entry/exit movement path of a movable scalpel, which will be described later, at an inner peripheral portion that is slightly displaced toward the proximal end side than the thread hooking portion 3a. Reference numeral 6 denotes a looper thread looper for supplying the looper thread 7, which is disposed below the fabric cloth 8, and has a feed dog that sequentially feeds the needle 1, decorative thread looper 3, and fabric cloth 8 in the direction of arrow A in FIG. It is linked to the operation of 9. 10 is a presser foot.

FIG. 2 shows the thread row at the end of sewing.
and the thread path guide 4, and the upper decorative thread section 5A stretched almost horizontally, and between the thread hooking section 3a of the decorative thread looper 3 and the sewing end section 5a of the fabric cloth 8, Due to the lower decorative thread portion 5B stretched in an inclined manner, it has a substantially triangular shape in plan view.

Reference numeral 11 denotes a decorative thread automatic cutting device, which is attached to a fixing plate 16 fixed to the front surface of the sewing machine body 15 through a long hole 13 provided in a mounting base plate 12 and a mounting bolt 14 so as to be able to adjust its inclination angle. . At the end of sewing, the decorative thread automatic cutting device 11 enters the triangular portion of the decorative thread 5 from diagonally backward and above with respect to the reciprocating plane of the decorative thread looper 3, and moves diagonally backward through the same path. The main component is a decorative thread cutting knife mechanism 19 consisting of a movable knife 17 that moves upwardly and a fixed knife 18.

FIGS. 3 and 4 show the decorative thread cutting device 11.
The movable knife 17 in the knife mechanism 19 is moved by an air cylinder 20 to a base guide (
The movable knife base 21 is slidably driven along the
It is fixed and connected to the distal end side, and a cutting edge-shaped thread hook portion 17a is formed at the distal end portion. Furthermore, the fixed knife 18 in the knife mechanism 19 is fixed and connected to the tip of a fixed knife base 22 that is connected to the mounting base plate 12. Further, a movable knife 1 is attached to the fixed knife base 22 via a liner 23 and a stop plate 24.
One end of a leaf spring 25 that presses the knife 7 toward the fixed knife 18 side is fixed. In FIG. 1, reference numeral 26 denotes a stopper for restricting the movement of the movable knife 17, which can be freely adjusted along the elongated hole 27.

The movable knife 17 of the female mechanism 19 in the decorative thread cutting device 11 has a thread hooking portion 17a at the tip end of the movable knife 17 of the female mechanism 19 of the decorative thread looper 3.
The upper decorative thread part 5A is stretched diagonally forward and downward so as to advance to the middle part of the upper decorative thread part 5A stretched almost horizontally between the thread guide 4 and the thread guide 4, and the upper decorative thread part 5A is pulled. The decorative thread part 5A is hooked and moved diagonally rearward and upward, and the drawn decorative thread part 5A is cut by a shearing action between it and the fixed knife 18. Note that the protrusion of the movable knife 17
A part of the exit movement path is constituted by a recessed portion 3b formed in the inner periphery of the decorative thread looper 3.

In the above structure, when a predetermined sewing operation is completed, when the pedal connected to the drive motor of the sewing machine is stepped on, the operation is stopped at the top dead center position of the needle bar, and the needle thread 2 and the looper thread 7 are automatically cut by a cutting device. Almost parallel to this, the air cylinder 11 operates,
Movable knife 1 of knife mechanism 19 in decorative thread cutting device 11
7 moves diagonally forward and downward. With this thrusting movement, the tip hook portion 17a of the movable knife 17 is stretched almost horizontally between the thread hooking portion 3a of the decorative thread looper 3 and the decorative thread path guide 4, as shown in FIG. The thread advances to the middle part of the upper decorative thread section 5A. Immediately after that, the movable scalpel 17 returns diagonally backward and upward, but at this time, the upper decorative thread section 5A is hooked by the tip hook section 17a of the movable knife 17, as shown in FIG. 4(A). It is pulled diagonally backward and upward. Then, the tip hook portion 17 of the movable scalpel 17
As shown in FIG. 4(B), when a moves above the fixed knife 18, the decorative thread 5 is automatically cut by the upper decorative thread portion 5A due to the shearing action between the two knives 17 and 18. become.

[0020] Here, the thread hooking portion 3 of the decorative thread looper 3
The upper decorative thread part 5A stretched between the decorative thread guide 4 and the decorative thread guide 4 is in a substantially horizontal position, and there is a sufficiently large vertical clearance between the upper decorative thread part 5A and the upper surface of the fabric cloth 8. In addition, the length is longer than the lower decorative thread section 5B stretched between the thread hooking section 3a of the decorative thread looper 3 and the sewing end section 5a, so the tip of the movable knife 17 is ,
Regardless of the thickness of the fabric cloth 8, the decorative thread 5 can be reliably hooked without any mistakes by sufficiently penetrating below the upper decorative thread portion 5A, and therefore the predetermined decorative thread cutting can be ensured. .

[0021]

As described above, according to the present invention, at the end of sewing, the movable knife of the knife mechanism enters the reciprocating plane of the decorative thread looper from diagonally backward and upward, and exits diagonally backward and upward. When moving, the tip hook of the movable knife holds the movable knife in a nearly horizontal position between the thread hooking part of the looper and the decorative thread guide, and vertically between the top surface of the fabric and the thread guide. Since the structure is configured so that the middle part of the upper decorative thread part that has been stretched is hooked and pulled while there is a sufficiently large clearance, even if the moving path of the movable knife is set somewhat rough, Regardless of various sewing conditions such as thread material, needle width, etc., and especially regardless of the thickness of the fabric, the decorative thread can be hooked without mistakes and the decorative thread can always be cut reliably. .

Furthermore, when stopping at the end of sewing, if a recess is formed in the inner periphery of the decorative thread looper corresponding to the moving path of entry and exit of the movable knife, the movable knife can be brought closer to the above-mentioned upper decorative thread. This makes it possible to move the decorative thread in and out, making it possible to cut the decorative thread more reliably.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts of a flat three-needle sewing machine that is an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the thread row.

FIG. 3 is a front view showing a specific configuration of the decorative thread cutting device.

FIG. 4 is a side view showing the specific configuration and operating state of the decorative thread cutting device.

FIG. 5 is a plan view showing the configuration of a decorative thread looper.

[Explanation of symbols]

1 needle 3 Decorative thread looper 3a Threading part 3b Recessed part 4 Thread path guide 5 Decorative thread 5A Upper decorative thread part 8. Fabric cloth 11 Automatic decorative thread cutting device 17 Movable knife 17a Hook part 18 Fixed knife 19 Female mechanism for cutting decorative threads

Claims (2)

[Claims] [Claim 1] At the end of sewing, the decorative thread looper enters the reciprocating plane of the decorative thread looper from diagonally rearward and upwardly, hooks the decorative thread on the tip hook, and moves diagonally backwardly and upwardly. A multi-needle sewing machine equipped with a movable knife and a decorative thread cutting knife mechanism comprising a fixed knife that cuts the decorative thread hooked by the movable knife and drawn diagonally backward and upwardly between the movable knife and the movable knife. In the decorative thread cutting device, the movable knife of the female mechanism is connected to an upper decorative thread portion whose distal hook portion is stretched between the thread hooking portion of the decorative thread looper and the decorative thread path guide at the end of sewing. cutting the decorative thread of a multi-needle sewing machine, characterized in that the decorative thread is moved so as to advance toward the middle part of the sewing machine, and is cut by hooking the middle part of the upper decorative thread part and pulling it diagonally backward and upward. Device. [Claim 2] Near the tip of the decorative thread looper,
2. The ornamental thread cutting device for a multi-needle sewing machine according to claim 1, further comprising a recessed portion formed in an inner peripheral portion corresponding to a path of entry and exit of said movable knife when stopped at the end of sewing.