JPH0560957B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a single thread chain stitch using a needle that passes through a needle hole in a needle plate and moves up and down, and a thread that cooperates with the needle and is carried by the needle. The present invention relates to a single thread chainstitch sewing machine equipped with a looper for forming a looper, and particularly relates to a thread gripping device at the beginning of sewing.

Prior Art Conventionally, thread gripping devices have been implemented in lockstitch sewing machines. The thread gripping device in this lockstitch sewing machine is designed to grip the end of the needle thread when the needle of the first stitch is raised to prevent the thread from coming off from the work cloth. However, there is a problem in directly applying the thread gripping device of this lockstitch sewing machine to a single-thread chainstitch sewing machine. In other words, in lockstitch sewing machines, the amount of thread taken up by the thread take-up is large, so if the needle thread is not gripped at the first stitch, the end of the thread will be removed from the workpiece fabric due to the thread pick-up action of the thread take-up when the needle rises for the first stitch. However, since the amount of thread taken up by the thread take-up is small in single-thread chainstitch sewing machines,
If the end of the needle thread is caught in the first stitch, a large amount of the thread end remains and is exposed on the workpiece cloth, which impairs the appearance of the sewn product.

For this reason, thread gripping devices have not been put into practical use in conventional single-thread chainstitch sewing machines, but if the thread gripping device is not used, the thread can move freely, making the amount of remaining thread unstable, and Threads were pulled out of processed cloth, etc. In order to prevent this, the end of the thread inserted through the needle may be made longer so that more thread remains, but this will cause problems in appearance as described above.

Purpose of the Invention The present invention was made in order to eliminate the above-mentioned defects, and its purpose is to stabilize the amount of remaining thread, thereby reducing thread dropout at the start of sewing and the appearance of sewn products. To provide a novel thread gripping device at the beginning of sewing which can reliably prevent damage.

Structure of the Invention In order to achieve the above object, in the present invention, a thread gripping body for grasping the thread end at the beginning of sewing in cooperation with the lower surface of the throat plate is disposed on the lower surface of the throat plate, and An operating means is provided for operating the thread gripping body after the thread loop formed as the needle moves up and down is captured by the looper and before the thread loop is expanded to the maximum extent.

Embodiment An embodiment embodying the present invention will be described below with reference to FIGS. 1 to 7. As shown in FIGS. 1 and 2, a needle plate 2 having a needle hole 2a approximately in the center is mounted on the upper surface of a bed portion 1a of a frame 1 of the sewing machine. A needle 3 is attached to an arm portion (not shown) of the frame so that it can pass through the needle hole 2a and move up and down. A looper 4 that rotates about one axis is provided in the bed portion 1a below the throat plate 2, and cooperates with the needle 3 to form a single thread loop using the thread T carried by the needle 3. It is designed to form seams.

Below the throat plate 2, the bed portion 1a is provided with a guide member 5 for guiding the movement of the sliding body 6 in the left-right direction (vertical direction in FIG. 2). A pair of left and right guide walls 7 are provided. A yarn handling body 8 is mounted between both guide walls 7 so as to be movable back and forth. When the looper 4 forms the thread ring R shown in FIG. 7, this thread handling body 8 engages with the thread ring R, tilts the thread ring R so that its opening surface faces upward, and moves into the thread ring R. is moved along the arrow shown in FIG. 2 to ensure the passage of the needle 3. In other words, following the forward movement, the thread ring R is moved to the left.
After engaging with the holder, the holder is moved diagonally back to the original position.

A needle receiver 9 having a needle receiver piece 9a bent downward at its distal end is attached to the bed portion 1a at its proximal end so as to be located below the needle hole 2a. A fixed blade 10 is attached to the bed portion 1a at its base end so that its left and right positions can be adjusted, and a blade portion 1 at the tip thereof is attached to the bed portion 1a.
0a is arranged below the thread handling body 8 in the vicinity of the needle receiving piece 9a. In addition, the bed portion 1a
A substantially triangular movable blade 11 having a blade portion 11a at the tip is rotatably attached to the base end by a shaft 12, and at the end of one sewing cycle, the movable blade 11 moves from the position shown in FIG. When the fixed blade 10 is rotated to the position shown in FIG.
The thread T is connected between the lower surface and the upper surface of the blade part 11a of the movable blade 11.
The side limbs of the fabric are cut off.

As shown in FIG. 3, the pillar portion 1b of the frame 1
is provided with a substantially disk-shaped cam body 13 that rotates in the direction of the arrow in FIG. 3 around a shaft 13a, and a pair of recesses 14 facing each other are formed in the outer peripheral edge of the cam body 13. The bottom surface of this recess 14 has an equal radius portion 14.
a and an inclined surface 14b that continues from the equal radius portion 14a to the equal radius outer peripheral surface of the cam body 13 is formed. A swing lever 15 is supported at the rear of the cam body 13 so as to be swingable around a shaft 15a, and an engagement piece 16 capable of engaging with the outer peripheral surface of the cam body 13 and the recess are provided at one end thereof. An engaging roller 17 that can be engaged with the bottom surface of the engaging roller 14 is provided, and a part of the outer periphery of the engaging roller 17 protrudes slightly downward from the engaging piece 16.
The swing lever 15 is biased by a spring (not shown) in a direction in which the engagement piece 16 engages with the outer peripheral surface of the cam body 13. Between the other end of the swing lever 15 and the movable blade 11 are a pair of links 18 and 19 extending in the front-rear direction, and a lever extending in the left-right direction and rotatably supported at an intermediate portion. 20, and the rear end of the first link 18 is connected to the other end of the swing lever 15. 1st link 1
The front end of the lever 8 is connected to the tip of the lever 20, and the second
The rear end of the link 19 is connected to the right end of the lever 20. The front end of the second link 19 is connected to the vicinity of the shaft 12 of the movable blade 11.

Therefore, when the engaging piece 16 is engaged with the outer circumferential surface of the cam body 13, the movable blade 11 is moved between the swing lever 15 and the first link 1, as shown in FIG.
8, the lever 20 and the second link 19 are arranged at a position separated from the fixed blade 10. On the other hand, when the engaging piece 16 is disposed within the recess 14 after being separated from the outer peripheral surface of the cam body 13 and the engaging roller 17 is engaged with the equal radius portion 14a of the recess 14, the above-mentioned The movable blade 11 is rotated clockwise from the position shown in FIG. 2 via the swing lever 15 and the like, and the movable blade 11 is placed in the position shown in FIG. 5.

A thread gripping body 21 is attached to the upper surface of the front end of the second link 19 with a screw 22, and is positioned by a positioning pin 23. At the tip of this thread gripping body 21, there is a thread gripping portion 2 having a substantially U-shape.
1a is integrally formed and engaged with the lower surface of the throat plate 2. As the second link 19 moves back and forth, the thread gripping body 21 moves between the front position shown in FIGS. 2 and 7 and the rear position shown in FIGS. 5 and 6. I'm starting to get it.

Next, the operation of the single thread chainstitch sewing machine configured as described above will be explained. Now, the processed cloth C shown in Figure 4
When sewing the button B on the top, the work cloth C and the button B are held between a feed bar that moves forward and backward and left and right on the throat plate 2 and a button holding device (none of which is shown). In this state, the needle 3 and looper 4 are operated, and the feed base is operated. During the sewing operation, the engaging piece 16 is engaged with the outer peripheral surface of the cam body 13, and the movable blade 11 is moved to the second The thread grip body 21 is placed and held at the standby position shown in the figure, and the thread grip body 21 is placed and held at the standby position shown in the figure. Then, at the end of one cycle of sewing, the cam body 13
When one recess 14 faces the engaging piece 16 and the roller 17, the engaging piece 16 separates from the outer circumferential surface of the cam body 13, and the swinging lever 15 moves as shown in FIG. is rotated clockwise,
The engaging roller 17 is located at the equal radius portion 14a of one of the recesses 14.
engage with. With this rotation of the swing lever 15,
The second link 19 is moved rearward via the first link 18 and the lever 20, and the movable blade 11 is rotated from the position shown in FIG. 2 to the position shown in FIG.
Blade portion 11a of movable blade 11 and blade portion 10 of fixed blade 10
The cloth side limb of the thread T is cut by cooperation with a.

Further, as the second link 19 moves backward, the thread gripping body 21 on the second link 19 moves backward from the position shown in FIGS. 2 and 7 to the position shown in FIGS. 5 and 6. will be moved.

Next, in order to sew a new button B onto the workpiece cloth C, the workpiece cloth C and button B are set on the throat plate 3, and then the sewing machine is started. Then, the cam body 13 shown in FIG. 3 is rotated in the direction of the arrow in the figure, and while the needle moves up and down once, the cam body 13 moves approximately 22.5 degrees.
rotated by degrees. In the first stitch, the engaging roller 17 is held engaged with the equal radius part 14a of the recess 14, so as shown in FIG. is needle hole 2
Behind a, the blade part 11a of the movable blade 11 is connected to the fixed blade 1.
They are arranged and held at the lower surface positions of 0, respectively. Then, the needle 3 passes through the sewing hole Ba of the button B, the work cloth C, and the needle hole 2a, and is moved up and down, and in synchronization with the up and down movement of the needle 3, the looper 4 is rotated in the direction of the arrow in FIG. However, in this case, even if the thread T is caught by the looper 4, the thread loop R is not formed because the thread end is not fixed to the work cloth C.
The thread T is suspended below the throat plate 2.

Subsequently, after the feed table is operated and the work cloth C and button B are moved by a predetermined amount in the direction of the arrow in FIG. 6,
Insert the needle 3 so that it passes through the sewing hole Bb etc. of button B.
A second vertical movement is performed. And this second
After the thread ring R formed as the needle 3 moves up and down in the stitches is captured by the looper 4, the thread ring R is not expanded to its maximum extent, that is, the state shown in FIG. 7 is reached. First, the swing lever 15 swings counterclockwise in FIG. 3 based on the engagement between the inclined surface 14b of the cam body 13 and the engagement roller 17.

As the swing lever 15 swings, the second link 19 is moved forward via the first link 18 and the lever 20, so that the thread grip body 21 is moved from the rear position shown in FIG. It is moved integrally with its second link 19 to the forward position shown in the figure.

That is, as the work cloth C is fed as described above, the cloth side limb of the thread T is sent upward in FIG. In this state, the thread gripping body 21 is moved forward, so that the end of the thread T is clamped between the thread gripping part 21a and the lower surface of the throat plate 2. Therefore, even if an upward tension is applied to the thread T by the thread take-up action of the thread take-up lever (not shown) after the thread ring R has been expanded to the maximum extent, the end of the thread T will not reach the sewing hole Ba of the button B.
There is no fear that the thread will fall off from the work cloth C, and the amount of remaining thread hanging from the needle 3 can be stabilized. Furthermore, when the thread loop R is widened to the maximum by the looper 4, the fabric side limb of the thread T is pulled out slightly against the thread clamping force of the thread gripping body 21, so that the amount of thread remaining after sewing is appropriate. It is maintained in a safe manner and there is no risk of damaging the appearance.

Further, as the second link 19 moves forward,
At the second stitch, the movable blade 11 is rotated back from the position shown in FIG. 5 to the position shown in FIG. 2. In this state, the sewing operation from the third stitch to the eighth stitch is performed, and as shown in Fig. 4, the thread T is passed between the pair of sewing holes Ba and Bb of the button B, and Button B is sewn onto workpiece cloth C. Then, by forming a stitch between the other pair of sewing holes Bc and Bd, sewing of button B can be completed. Note that the symbols "1 to 8" shown in FIG. 4 indicate the order in which the needles fall.

Effects As described in detail above, the present invention disposes a thread gripping body on the lower surface of the throat plate for grasping the thread end at the beginning of sewing in cooperation with the lower surface of the throat plate, and after starting sewing, the thread gripping body is arranged on the lower surface of the throat plate to grasp the thread end at the beginning of sewing. By providing an actuating means for actuating the thread gripping body after the thread loop formed as the thread moves up and down is captured by the looper and before the thread loop is expanded to the maximum, the needle This has the excellent effect of stabilizing the amount of thread remaining hanging down, reliably preventing the thread from falling out at the beginning of sewing and the risk of spoiling the appearance, and increasing the commercial value of the sewn product.

[Brief explanation of the drawing]

FIG. 1 is a left side view showing the main parts of a single thread chainstitch sewing machine embodying the present invention, and FIG. 2 is a plan view as well.
FIG. 3 is a reduced side view showing the operating mechanism of the thread gripping body, etc., FIG. 4 is a plan view showing the buttons, etc., FIG. 5 is a partial plan view showing the operating state of the thread gripping body, etc., and FIGS. FIG. 7 is also a partial perspective view. Throat plate...2, needle hole...2a, needle...3, looper...4, cam body...13, recess...14, rocking lever...15, engagement piece...16, engagement Koro...
17, first and second links... 18, 19, lever... 20 (the operating means is constituted by the above 13 to 20), thread grip body... 21, thread ring...
R, thread...T.

Claims (1)

[Claims] 1. A needle 3 that passes through the needle hole 2a of the needle plate 2 and moves up and down.
and a looper 4 that cooperates with the needle 3 and forms a single-thread chainstitch stitch using the thread T carried by the needle 3, the needle plate 2 A thread gripping body 21 disposed on the lower surface and used to grasp the thread end at the beginning of sewing in cooperation with the lower surface of the throat plate 2; and a thread loop formed as the needle 3 of the second stitch moves up and down after the start of sewing. Actuating means 1 for actuating the thread gripping body 21 after the thread ring R is captured by the looper 4 and before the thread ring R is expanded to the maximum extent;
3 to 20. A thread gripping device at the beginning of sewing.