JPS5940896A - Stitchyarn control 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 This invention calculates the required amount of thread for each seam knot in order to form a tight-tight main stitch by calculating based on data related to fabric thickness and fabric feed pinch. In the sewing machine that feeds out,
The present invention relates to a sewing thread control device for a sewing machine that changes an arithmetic expression for setting the amount of thread to be paid out in accordance with the type of sewing pattern.

Conventionally, when forming a final stitch using a sewing machine, the tension of the upper and lower threads is adjusted so that the intersecting point of the upper and lower threads is located at the center of the fabric, but this thread tension is equal to the amount of thread consumed for each seam knot. Quantity e
The thread amount P is obtained based on an arithmetic expression expressed as +p+2d (p: sewing pitch, d: right bank, k, 2: constant). data d.

Using the feed-out data calculated by an arithmetic circuit which inputs the stitch pitch data p from the stitch forming means, the thread feed-out device as shown in, for example, JP-A-58-79647 and JP-A-64-163148 is controlled. The required amount of thread was paid out before each stitch was knotted. However, with recent home sewing machines that can select and form various linear patterns such as straight stitches, zigzag stitches, and buttonhole stitches, it is possible to select and form various linear patterns such as straight stitches, zigzag stitches, and buttonhole stitches. The position of the cloth may vary depending on the sewing pattern.
When the thread is paid out according to the feeding data under the same conditions, the seam tension is not appropriate depending on the sewing pattern, resulting in the drawback that the quality of the sewn product becomes unstable.The present invention aims to eliminate the above-mentioned drawbacks of the conventional method. With the goal.

An embodiment of the present invention will be described with reference to the drawings. A presser bar 2 of min/l is provided with a sheath thickness detecting means 3 at its upper end, and the cloth is detected between a presser foot 4 and a throat plate (not shown). The weight is detected by the elevated position of the presser bar 2 when placed between the
Generates different digital codes depending on the thickness. sewing machine l
A panel 5 arranged on the front side is provided with a display section 6 displaying patterns corresponding to various linear patterns such as straight lines and zigzags, and a selection means 7 for sequentially selecting sewing patterns by operation. The dial 8 generates a signal for changing the data regarding the cloth feed amount of the pattern generation data (1-1), which will be described later, depending on its rotational position.

Next, the electric circuit will be explained using the block diagram shown in FIG.

MC is a microcomputer, sheath thickness detection means 8,
Input signals from each device of the selection means 7 and dial 8,
A storage section that stores in advance pattern generation data for controlling the cloth feed to the sewing machine to form various patterns and selection data regarding the type of sewing pattern, and corresponding pattern generation data and selection data by the selection operation of the selection means 7. and a reading means for reading out the pattern generation data, and a means for setting the needle thread payout amount so as to obtain a predetermined sewing tension based on the sewing pisotitator p obtained from the read pattern generation data and the detection data d from the sheath thickness detecting means 3. It has an arithmetic unit that performs arithmetic operations.

Next, the flow shown in FIG. 3 will be explained.

First, the selection means 7 determines whether the selected pattern is a straight line pattern or a needle swing pattern, and if it is a straight line pattern, e = k + p.
Select the 2d calculation formula for + and process the "calculation routine", and if it is a needle swing pattern, determine whether it is a special pattern of buttonholes or bar tacks or other needle swing patterns, and if it is a special pattern, For e=, select p-)-k2d+α2 and process the "calculation routine"; for other needle swing patterns, select 2d+α1 for e=k+p+ and process the "calculation routine" .

As shown in FIG. 5, the stitch pitch p in the needle swing pattern is f, which is made up of the needle swing amount X and the cloth feed amount Y, and is equal to TW.

α1. α2 is obtained by a function of the sewing pitch p and the thickness d, α1 is a number that corrects the amount of feeding so that each intertwining point of the upper and lower threads is located below the center of the fabric in a normal needle swing pattern, and α2 In special patterns (buttonholes, bar tacks), each intertwining point of the top and bottom threads is located below the center of the fabric, and in buttonholes and gate tacks, the stitches are closely spaced and overlap, so the amount that allows for that overlap This is the number that corrects the amount of movement so that it will move out as much as possible.

The present invention has the above-described configuration, and when a linear pattern is selected by operating the selection means 7, the calculation formula of 1p + 2d is selected for e-, and the stitch pitch data p from the storage section and the sheath thickness detection means are The fabric stitching data d from step 3 is read every time a stitch is formed, and arithmetic processing is performed, and based on the processing results, the thread letting out means pays out a predetermined amount of thread, and positions it approximately at the center of the fabric, which is the intertwining point of the upper and lower threads. One stitch's worth of stitches is formed using the thread fed out.

Next, if you select zigzag stitch, this is a needle swing pattern other than special patterns such as buttonholes, so e=J p+ k2
d+α1 is selected and arithmetic processing is performed so that the thread letting-out means lets out a predetermined amount of thread each time a stitch is formed. Also, if you select buttonhole sewing, this is a special pattern, so e =
k+ p+ k2 d+α2 is selected, and by arithmetic processing, the thread letting-out means lets out a predetermined amount of thread each time a stitch is formed, and at the left and right needle swing positions, in this embodiment, the sheath thickness detection means 3 is held down. Although shown as being arranged in relation to the rod, it may be arranged so that it directly engages with the fabric to detect the thickness, or it may be supported on the sewing machine frame.

As described above, according to the present invention, the calculation means calculates and outputs the length of needle thread required for each stitch formation based on the calculation formula that differs depending on the sewing pattern in relation to the stitch information and the detection signal; By providing a feeding means that feeds out the needle thread from the needle thread supply source before forming each stitch in relation to the calculation output, the feeding amount is set using a calculation formula that differs depending on the sewing pattern. Appropriate seam tension can always be obtained even when forming a pattern, resulting in the effect of stably improving the quality of sewn products.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the sewing machine of this embodiment, Fig. 2 is a block diagram of the electric circuit, Fig. 3 is the feed amount setting flow, Fig. 4 is a perspective view of a straight stitch, and Fig. 5 is a zigzag stitch. In the figure, Me... A microcomputer constituting the sewing control means and calculation means; 3... Thread feeding means; Prisoner 3I-3 figure

Claims (1)

[Scope of Claims] A sewing control means MC that separately stores stitch information regarding a plurality of different sewing patterns, selects stitch information by operation, and connects the stitch information to a stitch forming mechanism; A right bank detection means 3 detects the seam and generates a detection signal that varies depending on the thickness, and calculates the length of needle thread required for each stitch formation based on a calculation formula that differs depending on the sewing pattern in relation to the stitch information and the detection signal. A sewing thread control device for a sewing machine, comprising: a calculating means for outputting the calculated output; and a feeding means for feeding out the needle thread from a needle thread supply source before forming each stitch in relation to the calculated output.