JPS62102794A - Yarn tieing apparatus of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thread tying device for forming knots of upper and lower threads at the beginning and end of sewing in a lockstitch thread trimming sewing machine (the following).

[Conventional technology]

Conventionally, as described in Japanese Patent Publication No. 46-1136, in this type of lockstitch cycle sewing machine, at the end of the sewing operation, several tacking stitches were performed to prevent unraveling, and the pitch was adjusted. The so-called thread tying was performed by making the pitch smaller than the normal l-making pitch and twisting the upper and lower threads by reverse feeding to form a hit stitch.

[Problems that the invention attempts to solve 1 and 5] However,
This type of sewing machine did not have a mechanism for tying the thread at the beginning of sewing, so three to four stitches were reciprocated to form a locking stitch before sewing.

However, with this tacking stitch, the thread that hangs down at the beginning of sewing forms a "ball of thread" on the back side of the workpiece during back-and-forth sewing, damaging the appearance. This required extra overlap.

The present invention has been made in view of the problems of the conventional method as described above, and it forms knots with upper and lower threads at both the beginning and end of sewing, thereby improving the appearance of the seams at the beginning and end of sewing. The purpose of this method is 1- to ensure secure stitching.

[Means for solving problems]

Therefore, the present invention attempts to solve the above-mentioned problem by providing an untying device not only at the end of conventional sewing but also at the beginning of sewing, and by effectively controlling the reverse feed amount at each time. be.

〔Example〕

The present invention will be explained below based on the drawings.

Fig. 1(a) is an explanatory diagram of needle movement in one embodiment of the sewing process according to the present invention, (see Fig. 1(a)), (cl is the beginning of sewing (2/2) of (a), respectively), and each step at the end of the stitching and when the knot is not tied. An enlarged view is shown. In the figure, W indicates the work cloth, F indicates the normal feed direction of the fabric, P indicates the normal sewing feed pinch, and p indicates the small pinch of the feed at 8 o'clock when S is untied at the beginning of sewing and untied at the end of sewing, respectively. Pitch p is about 17" of regular pitch P.
A small feed amount of about 5 or less is set so that they fall at approximately the same position, and a close seam is formed.

Each untying process (each stamp number marked with te is shown in Figure 2 (
The corresponding steps of bt-j are shown in the operation sequence flowchart of the tree embodiment shown in a) and (b). These controls are performed by a circuit whose block diagram is shown in ¥3J.

30 is the start switch foot pedal of the sewing machine, hold the neutral position, and press `` '-=6i Nigo 5
The sewing machine is configured so that the sewing machine is started by pressing the front foot and the thread is trimmed by pressing the rear foot. Reference numeral 31 denotes a needle position detector provided on the upper shaft (main shaft) of the bottle 7, which detects the vertical position of the needle, and also counts the number of needles using a counter 33 in the control device 1cPU33. Digit 4-ta 35. A setting device 36 for the feed amount P, p, etc., a feed direction converter 37 that drives the feed adjuster of the sewing machine by a solenoid (not shown), a thread trimming solenoid 38, etc. are controlled by commands from the control device CPU 32.
The circuit is configured to be driven via each drive device 34.

Here, the feed position setting device 36 will be described in detail. In FIG. 4, 41 is a well-known cloth feeding means arranged on the underside of the bed so that the feeding dog appears and retracts on the throat plate to perform four feeding movements;
is the main shaft of the sewing machine, and 43 is the main shaft 42 via the crank rod.
The horizontal motion component is connected to the horizontal feed amount and 1
- a well-known feed adjuster that transmits information to the cloth feeding means; a 44-piece adjustment screw that can be rotated from outside the sewing machine and moves the tip forward or backward in the axial direction depending on the rotation angle; 45 is a cam that engages the tip of the adjustment screw 44; A well-known adjustment cam which has a surface and whose engagement position with the cam surface changes depending on the forward and backward positions of the adjustment cam and rotates around the middle part; 46 is a swing shaft fixed to the rear end of the adjustment cam 45;
Reference numeral 47 denotes a rond connected to the swing shaft 46 so as to change the feed amount of the feed dog by changing the horizontal motion component in the feed adjuster 43 in relation to the rotating position of the adjusting cam 450.

Further, in Fig. 4.5, 49 is a feed lever, and a part of the lever 49 has a pin 49a projecting in the horizontal direction.
is fixed. Reference numeral 48 denotes a spring provided at the base end of the lever, the other end of which is fixed to the machine frame, and the lever 40 is always urged upward by this spring 48. 50 is an adjustment shaft that loosely supports the base end of the lever 49 (ζ-opening support part and is rotatable relative to the machine frame); 51 is fixed to the adjustment shaft 50; This is a swinging arm that faces downward and protrudes horizontally.When the lever 49 is rotated downward, the pin 49a presses the swinging arm 51 downward, and the adjustment shaft 5
Rotate 0 downward. Adjustment shaft 500 toad end is connecting arm 52
It is connected to the swing shaft 46 via the adjusting shaft 50, and is connected to the rotating angle of the adjusting shaft 50 so that the feed amount is decreased or the feed direction is reversed.

Reference numeral 53 denotes an L-shaped operating lever with a bent portion loosely supported on an adjustment shaft, and an operating pin 53a extending above the swing arm 51 is fixed to one free end of the operating lever 53. 54 is a connecting arm that rotatably supports the other end of the operating lever; 55 is an L-shaped actuator that rotatably connects one end to the other end of 54 and rotatably supports the intermediate part on the machine frame. The other end is supported by the actuator 56a of the solenoid 56, and as the actuator 56a moves up and down, the operating rod 55
The connecting portion with the connecting arm 54 moves left and right.

A cam body 57 is fixed to the shaft of the stamping motor 58 and has one end surface formed into a cam shape. The cam surface 57a has a wall thickness that differs from the other end surface depending on the circumferential direction, and the engagement portion 54a at one longitudinal end of the connecting arm 54 and the cam surface 57
The cam surface 57a is disposed facing the cam surface 57a, and the distance from the engaging portion 54a is varied depending on the rotation angle of the cam surface 57a. Therefore, the connecting arm 54 comes into contact with the cam surface 57a by moving rightward in the figure, but since the timing of the contact changes depending on the rotation angle of the cam surface 57a, the amount of movement differs, and the amount of movement depends on the operating lever. 53 working pins 53
The swing arm 51 is rotated downward via a to reduce the feed amount. In other words, the connecting arm 54 is rotated by the rotation angle of the cam body 57 set by the stepping motor 58.
Since the moving distance is determined, by energizing the solenoid 56, a decrease in the feed amount corresponding to this moving distance can be obtained.

A potentiometer 59 is connected to the free end of the swing arm 51 via a link, and converts the amount of rotation of the swing arm 51 into an electrical signal.When the solenoid 56 is not energized, the adjustment screw 44 When the solenoid is excited, the feed amount set by the stamping motor 45 is detected.

Next, the operation shown in FIG. 1 will be explained with reference to FIG. Although the 7-can flow shown in FIGS. 2(a) and 2(b) is clearly illustrated, only the main points will be supplemented. First, in Figure (a), when starting (step 1), an initial reset is first performed (step 2), and the start switch pedal 30 is depressed forward (step 3). Next, in step 4, the yarn knot feed pitch p is set.

That is, the solenoid 56 is attracted by a solenoid drive signal issued from the drive device 34 to the feed position setting device 36.

The feed amount of the cam body 57 is set to the knot feed pitch p by the stepping motor 58, and the connecting arm 54 that is linked to the solenoid 56 comes into contact with the cam surface 57a, and the feed amount reaches the knot feed pitch p. Set. Next, drive the feed direction converter 37 to set the feed direction to the forward feed direction (F direction), and start the sewing machine at low speed (step 1
)'5, 6).

Then, the counter 33 counts the number of stitches N=1. (
Step 7.8) This one stitch is a preliminary needle movement to form a tangle between the upper thread and the bobbin thread. Next, feed direction converter 3
7 to set the sewing machine to reverse feed to form hit stitch stitches, count -2 to the number of Eri stitches on the counter 33 (Step 10.11) t, and then set the sewing machine to reverse feed. Stop low speed operation and tie thread S at the beginning of sewing
complete.

Next, in FIG. 2(b), in step 13, the normal sewing feed amount P is set, the forward feed direction F is specified, and the start switch/sote pedal 30 of the sewing machine is stepped forward (step 13.14). The sewing machine speed is set at the regular sewing speed, and may be stopped midway if necessary (Steel 1
6,17). Next, in step 18, step back on the start switch pedal 30 to set the sewing machine's high-speed sewing speed to 0FFI.
, (steps 18 and 19), the yarn knot feed pitch is set.

The sewing machine is fed backwards at low speed to form stitches (steps 21 and 22'), and the counter 33
After counting the number of stitches N=2 (steps 23 and 24), the thread is trimmed (step 25), and the needle position detector 3
1, the needle up position is detected and the sewing machine is stopped (step 26), completing the % sewing and thread tying E at the end of sewing.

With the stitching of this embodiment described above, reliable thread knots are formed at the beginning and end of sewing, eliminating the occurrence of thread balls, long bobbin threads remaining, and backstitching.

Among them, a small pinch p for forming the thread knot of the above embodiment.
Although the number of reverse feeds is two stitches each, it is of course possible to use more than two stitches.

〔Effect of the invention〕

After explaining the above, I can do it! According to the present invention, a knot is formed with the upper and lower threads at the beginning and end of the stitching, improving the appearance of each stitch, ensuring prevention of fraying, and shortening the length of the tie stitch. This has the effect of improving sewing productivity. Of course, you can do this only at the beginning of sewing, or
It may be applied only to the end of sewing.

[Brief explanation of drawings]

FIG. 1(a) is an explanatory diagram of needle movement in an embodiment of the sewing process according to the present invention, FIG. 1(b) and FIG. ),'(
b) is the operation no-ken flowchart of this embodiment, the third
The figure is a block diagram of an example of the control circuit, FIG. 4 is a diagram of the feed position setting device, and FIG. 5 is a block diagram thereof. S... Thread knot at the beginning of sewing E... Thread knot at the end of sewing F... Forward feed direction P... Sewing feed pitch p... Thread knot feed pitch 32... Control device CPU W... Work cloth

Claims (1)

[Claims] At the beginning and end of sewing of the lockstitch sewing machine, the feed amount is set to a minute feed amount by the work cloth feed amount setting means, and the feed direction is set to the reverse feed direction by the feed direction conversion means, and the hitch stitch stitches are A thread tying device for a sewing machine, characterized in that it is configured to form a knot of at least two stitches.