JPS6023633B2 - Needle thread tension adjustment device for sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a needle thread tension adjusting device for a sewing machine, in particular, the needle thread tension is automatically adjusted according to the sewing pattern, and the number of fabrics, type of fabric, etc. can be adjusted in stages by key operation. This invention relates to a needle thread tension adjusting device for a sewing machine that can increase or decrease the tension of a sewing machine.

With conventional sewing machines of this type, the user manually adjusts the thread tension dial based on his or her own experience to correct uneven stitches caused by the sewing pattern, number of fabrics, type of fabric, type of needle and thread, and sewing speed. I was using it with various adjustments.

The present invention automatically adjusts the tension of the upper thread to the optimum value based on the sewing pattern without manual intervention as in the past, and also changes the number of fabrics, type of fabric, etc. The present invention provides a novel needle thread tension adjustment device for a sewing machine that is equipped with a key and can adjust the tension of the needle thread in stages.

In other words, in general, when a user adjusts the needle thread tension of a sewing machine, it is difficult to judge whether to change it based on the sewing pattern, but it is easy to judge whether to change it based on the number of fabrics, the type of fabric, etc. . Therefore, the needle thread tension adjusting device of the present invention has a structure in which the tension of the needle thread is automatically adjusted to the optimum value according to each pattern based on sewing patterns that are difficult to judge by humans. This is because the tension corresponding to each pattern is stored in the control circuit, and when a straight line is selected, for example,
When a buttonhole is selected, a value of ``1'' is output from the storage device and the tension is set to a unit value of ``1'', and when a buttonhole is selected, a value of ``8'' is output from the storage device and the tension is set near the unit value of ``8''. Set the required tension in advance so that it is set to .

It should be noted that among these preset tensions, the tension corresponding to 7, ie, 4 pieces of fabric, is set under conditions of medium thickness. Next, if the number of fabrics or fabrics deviate from the standard, use the tension adjustment ``11'' key on the operation panel to increase or decrease the number.

For example, if the number of fabrics is large or the fabric is thick, press the ``11'' key to increase the needle thread tension, while if the number of fabrics is small or the fabric is thin, press the ``1'' key to decrease the needle thread tension. In this case, the tension is automatically increased or decreased by one step with a single keystroke.If the number of fabrics or the thickness of the fabric deviates significantly from the standard, press the key again to increase or decrease the tension. The tension can be increased or decreased automatically by the next step.Furthermore, since it is affected by the type of needle and thread and the sewing speed, the tension can be adjusted by pressing the "11" or "-" key as necessary. It is. That is, the needle thread adjustment device for a sewing machine of the present invention includes a needle thread tension adjustment section that freely adjusts the tension applied to the needle thread of the sewing machine by driving a driver section;
A counter section that counts the magnitude of the tension via a microswitch that detects the rotation angle of a cam that rotates according to the magnitude of the tension of the upper thread; and a counter section that counts the magnitude of the tension according to the pattern selected in the pattern selection section. a storage unit for outputting the value; a tension adjustment “ten” key and a tension adjustment “one” key for increasing or decreasing the tension of the upper thread according to missionary work, etc.; an adder/subtractor and a buffer unit; , a tension adjustment that increases or decreases the tension value input from the storage unit using the adder/subtractor and temporarily stores it in the buffer unit based on a signal from the tension adjustment “eleven key” or the tension adjustment “one” key; and: a comparator section that controls the driver section by comparing the tension value after the increase/decrease from the buffer section of the tension adjustment section with the tension value from the counter section. It is a new creation of something that

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 1 is a block diagram schematically showing a needle thread tension adjustment device of a sewing machine, which includes an input section 1, a control section B, and an output section.
The input section 1 includes a needle thread tension detection section 11, a tension adjustment section 12, and a pattern selection section 13, and also includes a control section 01, a counter section 21 connected to the needle thread tension detection section 11, and a tension adjustment section 1.
2, an adjustment section 24 consisting of an adder/subtractor 22 and a buffer 23, and a storage section 25 connected to the pattern selection section 13.
It further comprises a comparator section 26 connected between the counter section 21 and the adjustment section 24, a driver section 27 connected to the comparator section 26, and an output section connected to the driver section 27. It consists of a motor section 31 and an upper thread tension adjustment section 32 connected to the motor section 31.

The needle thread tension adjustment section 32 freely adjusts the tension of the needle thread of the sewing machine by, for example, sandwiching the needle thread between a pair of presser plates pressed together, as described in detail below. By changing the position of the presser plate according to the drive of the motor section 31, for example, forward rotation, reverse rotation, and the rotation angle, the tension of the upper thread can be freely adjusted. This allows the tension of the thread to be determined. Since the motor section 31 is freely driven by the output of the driver section 27, and the driver section 27 is driven by the signal from the comparator section 26,
Eventually, the tension of the upper thread is adjusted by the output of the comparator section 26. The needle thread tension detection unit 11 of the input unit 1 detects the actual tension of the needle thread at any given time. For example, the needle thread tension detection unit 11 detects the current tension of the needle thread by detecting the position of the presser plate and the driving state of the motor unit. Then, the determined value of the tension of the needle thread is counted by the counter section 21 and input to the comparator section 26. The pattern selection section 13 sets in advance the necessary needle thread tension as a plurality of values according to various sewing patterns, and stores these values in the storage section 25 of the control section 0. A specific value is selected from among them depending on the selected pattern. For example, a specific value as the tension of the needle thread stored in the storage unit 25 is sent to the buffer unit 23 depending on the position of the cam. Let's make it possible. The tension adjustment section 12 is for arbitrarily adjusting the tension value. For example, when the tension adjustment section 12 presses the addition button 14 as the 11 key once, the specified tension value of one unit is inputted from the storage device section 25. If the adder/subtractor 22 is operated so as to be added to the value of , and the subtraction nail 15 as the tension adjustment "1" key is pressed twice, the above specified two units of tension value will be stored in the storage unit 25.
The adder/subtractor 22 is operated so as to be subtracted from the input value, and the added and subtracted values are temporarily stored in the buffer section 23. The comparator section 26 compares the magnitude of the value input from the buffer section 23 and the value input from the counter section 21 and outputs the difference to the driver section 27 in order to match the value input from the buffer section 23 with the value of the upper thread adjustment section 32. The value is input to drive the motor section 31. In the embodiment shown in FIG. 1, as the input section 1, the needle thread tension adjustment section 11 includes a needle thread tension initial value setting switch 17 and a stepwise increase switch 16.
and an addition button switch 14 as the tension adjustment section 12.
and a subtraction button switch 15, and the pattern selection section 13 further includes three switches 18a for selecting three different patterns;
18b and 18c.

Next, FIG. 2 shows the needle thread tension adjustment section 32 and the needle thread tension detection section 1.
1, and in Figure 2, 51
5 is a sewing machine body, 52 and 53 are a pair of presser plates, and 54 is a shaft. The shaft 54 has one end fixed to the sewing machine main body 51, and two presser plates 52, 5 are attached to the fixed one end side.
3 is slidably fitted together with a coiled spring 5.
Further, a threaded part 56 is provided at the other end of the shaft 54, and a threaded hole 58 provided in the boss of the feed gear 57 is screwed into the threaded part 56. 60 to form a so-called free end. As shown in FIG. 2, the feed gear 57 rotatably provided in the cam body 59 has a screw hole 58 in its central boss portion, and the screw hole 58 is screwed into the screw portion 56 of the shaft 54.
When the feed gear 57 is rotated, the threaded portion 56 of the shaft 54
The boss portion of the feed gear 57 is displaced along the axis of the shaft 54, and the length of the spring 55 is adjusted by this displacement, so that the pressure of the spring 55 against the holding plates 52, 53 changes. . The rotation of the feed gear 57 is caused by the engagement of teeth 62 of the feed gear 57 with protruding pawls 61 provided in the cylindrical hole of the cam body 59 that supports the feed gear 57, and as the cam body 59 rotates. The feed gear 57 rotates or is displaced in all directions along the axis of the shaft 54. The cam body 59 is provided with a bar-shaped pawl 61 extending parallel to the axis in its cylindrical hole, and the teeth of the feed gear 57 are engaged with the pawl 61 so as to be movable so as to rotate together. A limit cam 63 is mounted on the left side of the outer peripheral surface of the cam body 59.
Counting cams 64 are formed in two stages on the right side and correspond to a pair of microswitches 16 and 17 provided on the sewing machine body 51, respectively. The cam body 59 is rotated by a motor 31 provided in the sewing machine body 51 via a reduction gear 65. The two presser plates 52 and 53 constitute a needle thread tension adjustment section 32 as a pair,
The upper thread is held in a pressed state between two presser plates 52 and 53.

That is, both of the presser plates 52 and 53 are pressed against the sewing machine body 51 side by the spring 55, the one on the right side of the apparent upper presser plate is fixed to the sewing machine body 51, and the one on the left side is pressed by the spring on the right side presser plate. It is held in pressure contact with the plate. When the cam body 59 is rotated, the distance between the spring 55 bridged between the feed gear 57 displaced in the axial direction of the shaft 54 and the left holding plate 52 changes, so that the pressure of the spring 55 is applied to the holding plate 52. The pressure between plates 52 and 53 can be adjusted. The cam body 59 has a reduction gear 65
The limit cam 63 and the count cam 6 are rotated forward or reverse by the motor 31 via the
4, the corresponding microswitches 16 and 17 are activated. In other words, the microswitches 16 and 17 can detect the rotation angle of the cam body 59, that is, the positions of the limit cam 63 and the count cam 64, and constitute the needle thread tension detection section 11. The limit cam 63 integrally formed as the cam body 59 is provided with grooves at one location on the circumference, and the count cam 64 is provided with grooves at 10 locations.
The rotation angle is set, for example, in a range of about 300 degrees, and the tension is adjusted within that range. The limit cam 63 is used as a signal when setting the initial state. For example, when the power is turned on, it is rotated until a signal is received from the limit cam 63, and that state is set as the initial position. The count cam 63 sets the counter to 0 at the initial position of the limit cam 63, counts the number of subsequent grooves with the micro switch 17, and turns the motor 31 until it matches the preset value according to the pattern, and matches the count. Then, the motor 31 is stopped and a predetermined tension is obtained. That is, when the cam body 59 is rotated by the motor 31, one pawl 61 is provided inside the cam body 59 and a feed gear 57 is inserted, and when the cam body 59 rotates, the pawl 61 hits the feed gear 57. The feed gear 57 also rotates, and the feed gear 57 meshes with the threaded portion 56 of the shaft 54 and moves left and right along the threaded portion 56 in all directions of the axis of the shaft 54, so that the spring force of the spring 55 is freely adjusted. It turns out. As described above, the structure of the tension adjusting device consisting of the cam body 59, the feed gear 57, the shaft 54, and the spring 55 facilitates tension adjustment when assembling the sewing machine. The feed gear 57 engaged with the threaded portion 56 of the cam body 5 is turned by hand to set the spring 55 to a specific tension.
9 is combined with the feed gear 57 at a specific angle, the initial position of the count cam 63 can be easily set.

4 shows the push pins 14 and 15 of the tension adjustment section 12 provided on the operation panel as the tension adjustment section 12, and FIG. Step pattern selection cam body 72 and microswitches 18a, 18b
, 18c are shown. The pattern selection cam body 72 having this structure can be manually rotated together with the dial 71, and has three different stages of pattern selection cams 73, 74, 75 integrally provided in its cross-sectional view, and the pattern selection cam body 72 can be moved via a gear 76. Rotate gear 77. That is, the pattern selection cams 73, 74, and 75 of the pattern selection cam body 72, which are rotated and selected by the dial 71, constitute the pattern selection section 13, and the tension value of the storage device section 25 is set. As mentioned above, the input section is the tension detector's "CT" and "LT"
microswitches 16 and 17, 11 and 1 push spades 14 and 15 for tension adjustment, and 11 and 1 push spades 14 and 15 as pattern selection detectors.
a” “b” “c” (micro switches 18a, 18b
, 18c) and is input to the control section.

The control unit also includes a counter 21 that counts the tension detector's "CT" switch 16 or resets it with the "LT" switch 17, a storage device 25 that stores the tension corresponding to each pattern, and a plurality of pattern selection detectors. switches 18a, 18
The storage device section 25 is addressed by b and 18c, and the buffer 23 into which one of the storage devices 25 is inputted, the adder/subtractor 22 and the counter that add and subtract the buffer 23 by the "11" push nails 14 and 15 for tension adjustment. 21 and a buffer 23, and a driver 27 that rotates the motor 31 with a signal outputted from the comparator 26 if there is a difference. Furthermore, the output section includes a motor 31 that rotates in response to a signal from the driver 27 and an upper thread tension adjustment section 32 that is controlled by the motor.
It consists of Therefore, when you select the desired pattern with the dial 71 and give an instruction to adjust the tension arbitrarily according to missionary work etc. with the "1" press, the control section 0 and the output section m will operate automatically. The tension of the upper thread is set to a required value.As detailed in the above embodiment, according to the present invention, the memory outputs the necessary tension value according to the pattern selected in the pattern selection section. Since it is equipped with a device section, a counter section that counts the amount of tension, and a comparator section, it is possible to automatically adjust the needle thread tension to the optimum value based on the sewing pattern, which is difficult to judge manually. In addition, it is equipped with a tension adjustment key (11) and a tension adjustment (1) key to adjust the tension of the upper thread, as well as a tension adjustment section consisting of an adder/subtractor and a buffer section, making it easy to judge the number of fabrics and fabrics. The tension of the upper thread can be easily and reliably manually adjusted in stages according to the type of thread.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a needle thread tension adjusting device of a sewing machine according to the present invention, and FIGS. 2 to 5 are explanatory diagrams of main parts of FIG. 1. DESCRIPTION OF SYMBOLS 11... Needle thread tension detection section, 12... Strong adjustment section, 13... Pattern selection section, 21... Counter section, 23...
...Buffer section, 25...Storage device section, 26...
・Comparison section, 27...Driver section, 31...
...Motor part, 32...Needle thread tension adjustment part. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A needle thread tension adjustment section that freely adjusts the tension applied to the needle thread of the sewing machine by driving the driver section; and a micro switch that detects the rotation angle of the cam that rotates according to the magnitude of the tension of the needle thread. a counter section that counts the magnitude of the above-mentioned tension via; a storage section that outputs the necessary tension value according to the pattern selected in the pattern selection section; A tension adjustment "+" key and a tension adjustment "-" key for increasing or decreasing the tension; and an adder/subtractor and a buffer section, based on the signal from the tension adjustment "+" key or the tension adjustment "-" key. a tension adjustment section that increases or decreases the tension value input from the storage device section using the adder/subtractor and temporarily stores it in the buffer section; a tension value after being increased or decreased from the buffer section of the tension adjustment section; A needle thread tension adjusting device for a sewing machine, comprising: a comparator section that compares tension values from the counter section and controls the driver section.