JPH0681482U - Button sewing machine looper - Google Patents

Abstract

(57) [Summary] [Purpose] Of the loop portion of the needle thread, the portion from the bottom surface of the fabric to the thread shifting tool is closed in a straight line, and when the needle descends, it enters the loop portion of the needle thread. Preventing such problems, and performing good button sewing without skipping stitches. [Structure] A first thread hooking portion 4a having a claw-shaped tip, a second thread hooking portion 4b having an outer peripheral surface having a bulging arc shape, and a shaft portion 4c for attaching to a front end portion of a looper shaft (not shown). In the looper 4 of the button sewing machine including
The outer peripheral surface of the bulging arc of the thread hooking portion 4b is hollowed out and cut off.
and a looped portion X of the needle thread X formed on the back side of the tip portion of the needle 3 when the sewing machine is operated by the gouged cutting surface 4d.
The part X11 extending from the lower surface of the cloth Z of No. 1 to the thread pulling portion 5a of the thread pulling tool 5 is configured to be linearly closed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a looper for a single-loop stitching button sewing machine used for sewing buttons on clothes, for example.

[0002]

[Prior art]

 FIG. 4 is a schematic view of a main part of a sewing machine with a single chain stitch button, and FIG. 5 is a side view showing the shape of a conventional looper. In FIG. 4, 1 is a sewing machine bed and 2 is a top surface of the sewing machine bed 1. The needle plate has a through hole 2a formed in the center thereof. A needle 3 is provided above the needle plate 2 and is configured to perform a vertical movement indicated by an arrow A-A1 when the sewing machine operates. As shown in FIG. 5, the looper 4 includes a first thread hooking portion 4a whose tip is formed in a claw shape and a second thread hook 4 whose outer peripheral surface is formed in a bulging arc shape. The sewing machine is equipped with a portion 4b and a shaft portion 4c, and is attached to the front end of a looper shaft (not shown) inside the sewing machine bed 1 via the shaft portion 4c. ) Is rotated in the direction of arrow B, and cooperates with the needle 3 to form a stitch.

Reference numeral 5 denotes a thread pulling tool having a thread pulling portion 5a having a claw-like tip, which is interposed between the needle plate 2 and the looper 4 and is attached to the looper shaft as the looper shaft rotates. The cam (not shown) moves left and right in the direction of arrow C-C1. When the needle 3 descends in the direction of arrow A, it advances in the direction of arrow C and loops the needle thread X. The portion X1 is hooked by the yarn pulling portion 5a so as to be pulled to the side of the lowered position of the needle 3, and when the needle 3 is raised in the arrow A1 direction, it is retracted in the arrow C1 direction. . In FIG. 4, Z is a cloth which is appropriately fed on the needle plate 2 by a feeding device (not shown), and Y is a button which is sewn on the cloth Z and has button holes YL and YR.

The button sewing machine having the above-described structure performs the operation shown in FIGS. 6 to 10 to sew the button Y on the cloth Z. The buttoning operation will be described below. First, as shown in FIG. 6, when the needle 3 in the right hole YR of the button Y starts to move upward slightly from the bottom dead center position, the needle thread is attached to the back side of the tip of the needle 3. A loop portion X1 of X is formed, and the tip of the first yarn hooking portion 4a of the looper 4 enters this loop portion X1. At this time, the loop portion X0 of the needle thread X in the previous step is hooked between the first thread hooking portion 4a and the second thread hooking portion 4b, and the thread pulling tool 5 uses The approaching portion 5a moves to the left so as to approach the loop portion X0 of the previous process.

Next, as shown in FIG. 7, when the needle 3 rises from the right hole YR of the button Y, the looper 4 spreads the loop portion X1 of the needle thread X at the first thread hooking portion 4a and moves it forward. The loop portion X0 in the process is removed from the rear side of the thread hooking portion 4a. At this time, the yarn pulling tool 5 retreats to the right as the needle 3 rises.

Subsequently, as shown in FIG. 8, when the needle 3 descends from the top dead center position, the button Y and the cloth Z are white by a feeding mechanism (not shown) provided inside the sewing machine. It is sent in the direction of the pull-out arrow, and the left hole YL of the button Y is located immediately below the needle 3. At this time, the looper 4 rotates in the direction of the arrow B to twist the loop portion X1 of the needle thread X and moves it from the first thread hooking portion 4a to the second thread hooking portion 4b side. At this time, the previously removed loop portion X0 in the previous step is pulled upward and tightened. At the same time, the yarn pulling tool 5 moves to the left so that a part of the loop portion X1 of the needle thread X is hooked on the yarn pulling portion 5a and is brought to a position where it does not hinder the lowering of the needle 3.

Next, as shown in FIG. 9, as the needle 3 descends and enters the left hole YL of the button Y, the loop portion X0 of the needle thread X in the previous step is tightened and the knot ( Seams) are formed. At the same time, the loop portion X1 of the needle thread X moves while being twisted from the first thread hooking portion 4b of the looper 4 to the second thread hooking portion 4a, and the lower surface of the button Y (shown in the figure). Although it is not, it is actually stretched obliquely from the lower surface of the cloth Z) to the thread hooking portion 5a of the thread pulling tool 5 (shown as X11 in FIG. 9).

Next, as shown in FIG. 10, when the needle 4 in the left hole YL of the button Y starts to move up slightly from the bottom dead center position, the back side of the tip of the needle 3 A loop portion X2 of the next needle thread X is newly formed at the position, and thereafter, the process returns to the step of FIG. 6 described above.

[0009]

[Problems to be solved by the device]

 In the case of the looper of the conventional button sewing machine having the above-described configuration and operation, when the process of FIG. 8 is transferred to the process of FIG. 9 in the series of button sewing shown in FIGS. Of the loop portion X1 of the thread X, the loop portion X11, which is in a state of being stretched obliquely from the lower surface of the cloth Z to the thread shifting tool 5, as shown in FIG. Although not formed, a void S 1 may actually be formed on the lower surface of the cloth Z). This void S does not always occur, but due to the subtle imbalance of the thread, the material, the thread tension, etc., the thread reaching the needle hole from the right hole YR of the button Y through the looper 4 is folded back. This occurs when the yarn pulling tool 5 does not completely adhere to the yarn pulling tool 5, regardless of the action of the tool 5. Therefore, when the needle 3 descends, the needle 3 enters the space S as shown in FIG. 12, and the first thread of the looper 4 is inserted into the loop portion X1 of the needle thread X. Even when the hanging portion 4a enters, the thread is unentangled and unraveled, and as a result, there is a problem in that stitching may occur and the button may not be sewn securely. Moreover, since the void S is always generated, there is a problem that the thread tension and the like must be finely adjusted, and the work efficiency is deteriorated.

The present invention has been made to solve the above problems, and by a very simple structural improvement, when the needle descends, the needle enters the loop portion of the needle thread. It is an object of the present invention to provide a looper for a sewing machine with buttons, which prevents the stitches from being stitched securely and can perform good button sewing.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, a looper of a sewing machine with buttons according to the present invention comprises a first thread hooking portion having a claw-shaped front end, a second thread hooking portion having an outer peripheral surface in a bulging arc shape, and a sewing machine. In a looper for a sewing machine with buttons, which has a shaft portion for performing one rotation movement for one reciprocating movement of the needle when the sewing machine operates, in the circular outer peripheral surface portion of the second thread hooking portion, the cut surface is cut. By forming the thread and hooking the thread on the cut surface, the part of the loop part of the needle thread that is created on the tip side of the needle when the sewing machine operates closes in a straight line from the bottom surface of the fabric to the thread shifting tool. It is configured to be in a closed state.

[0012]

[Action]

 According to the looper of the button sewing machine configured as described above, when the needle enters the left hole of the button, the loop portion of the needle thread is overlapped so that it is in a state of being linearly closed from the lower surface of the cloth to the thread shifting tool. Therefore, it is possible to prevent the stitches from entering the needle thread loop portion at the time of descending the needles and prevent the stitch skipping.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 is a side view showing the shape of a looper of a sewing machine with buttons according to an embodiment of the present invention. In FIG. 1, the same components as those of the conventional example shown in FIG. , And detailed explanations thereof are omitted. Further, since the structure of the essential part of the button sewing machine having such a looper is the same as that shown in FIG. 4, description thereof is omitted here to avoid duplication.

In FIG. 1, reference numeral 4d denotes a gouging and cutting surface formed by hollowing the bulging arc-shaped outer peripheral surface portion of the second thread hooking portion 4b, and as will be described later, the tip portion of the needle 3 when the sewing machine operates. In the loop portion X1 of the needle thread X made on the back side of the thread, the angle of the triangular thread formed with the thread puller 5 as the apex is made small between the looper 4 and the thread puller 5, and the cloth Z The portion X11 extending from the lower surface of the yarn pulling tool 5 to the yarn pulling tool 5 is closed in a straight line.

With the above configuration, when the needle 3 descends and enters the left hole YL of the button Y (when the process of FIG. 8 of the conventional structure shifts to the process of FIG. 9), the needle thread Of the loop portion X1 of X, the loop portion X11 which is in a state of being stretched obliquely from the lower surface of the cloth Z to the thread pulling tool 5 is, as shown in FIG. 2 and FIG. By being hooked on the surface 4d, the button Y is closed in a straight line from the lower surface (not shown, but actually the lower surface of the cloth Z) to the thread pulling portion 5a of the thread pulling tool 5. Therefore, since the space S unlike the conventional structure is not formed, the descending needle 3 is prevented from entering the loop portion X11 of the needle thread X, and is lowered to the front position of the loop portion X11. As a result, stitch skipping is prevented and a predetermined seam is reliably formed.

The cut-out cutting surface 4d formed on the second yarn hooking portion 4b of the looper is not limited to the shape of the embodiment, and is not limited to the shape of the embodiment and extends from the lower surface of the cloth Z to the yarn pulling portion 5a of the yarn pulling tool 5. If the loop portion X11 of the needle thread X can be closed in a straight line, the shape may be slightly changed.

[0017]

[Effect of device]

 As described above, according to the present invention, it is only necessary to make a very simple structural improvement in which the cutting surface is formed by hollowing out the bulging arcuate outer peripheral surface portion of the second thread hooking portion, and when the sewing machine operates. The loop portion of the needle thread from the lower surface of the cloth to the thread pulling portion of the thread pulling tool is closed in a straight line, and it is possible to eliminate the conventional triangular void in that portion. Therefore, when the needle descends, it is possible to prevent the occurrence of stitch skipping that accompanies the needle entering the loop portion of the needle thread, and it is possible to ensure the predetermined button sewing and make it favorable. It has a practical effect that it is not necessary to perform fine adjustment work such as thread tension.

[Brief description of drawings]

FIG. 1 is a side view showing the shape of a looper of a button sewing machine according to the present invention.

FIG. 2 is a perspective view of a main part of the looper shown in FIG. 1 during operation.

FIG. 3 is a plan view of the same.

FIG. 4 is a schematic view of a main part of a general sewing machine with a single chain stitch button.

FIG. 5 is a side view showing the shape of a conventional looper.

FIG. 6 is a schematic view of a main part showing a first step of a conventional button sewing step.

FIG. 7 is a schematic diagram of a main part showing a second step of the above.

FIG. 8 is a schematic diagram of a main part showing a third step of the above.

FIG. 9 is a schematic view of an essential part showing a fourth step of the same.

FIG. 10 is a schematic diagram of a main part showing a fifth step of the same.

FIG. 11 is a perspective view of a main part of the conventional structure during a looper operation.

FIG. 12 is a perspective view of a main part in the next step of FIG. 11.

FIG. 13 is a plan view of the same.

[Explanation of symbols]

 3 Needle 4 Looper 4a 1st thread hooking part 4b 2nd thread hooking part 4c Shaft part 4d Grip cutting surface 5 Thread pulling tool 5a Thread pulling part

Claims (1)

[Scope of utility model registration request] 1. A first thread hooking portion having a claw-like tip, a second thread hooking portion having an outer peripheral surface in a bulging arc shape, and one rotation movement for one reciprocating movement of a needle when the sewing machine is operated. In a looper of a sewing machine with a button having a shaft portion for causing the cutting, a cutting surface is formed by scooping the arc-shaped outer peripheral surface portion of the second thread hooking portion, and a thread is hooked on the hollow cutting surface to sew the sewing machine. The sewing machine with buttons characterized in that the portion of the loop portion of the needle thread made on the tip end side of the needle from the lower surface of the fabric to the thread shifting tool is closed in a straight line when the needle is operated. Looper.