JPH04141190A - Sewing machine with embroidering function - Google Patents

Abstract

PURPOSE:To prevent an upper thread from entaglement in a thread take-up due to the slackness of the upper thread, thread cut due to excessive tension, and a sewing needle from bending by operating an upper thread drawing-out device to draw out a predetermined length of the upper thread when the tension detected by a tension detecting means exceeds a predetermined value. CONSTITUTION:To set initially a position of an embroidering frame 2, a manual- automatic change-over switch 16 is changed over to a manual mode. When the tension of an upper thread 22 exceeds a predetermined value by the movement of the embroidering frame 2, a thread take-up spring 34 is elastically deformed to the upper limit position shown by the two-dot dash line in Fig.2, and a shutter 35 integral with the treat take-up spring is pivoted to a position for interrupting the light path of a photosensor 36 which outputs a detecting signal. Thus, current is supplied to a pulse motor 26 of an upper thread drawing- out device 25 to rotate a drawing-out roller 27 and draw out a predetermined length of the upper thread 22. By repeating these operations, the tension of the upper thread 22 initially set is made proper to prevent the thread cut and the bending of a sewing needle 20 from occurring.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a sewing machine with an embroidery function that performs embroidery stitches by horizontally moving an embroidery frame in synchronization with the vertical movement of a sewing needle. Regarding.

(Prior art) As a conventional example of a sewing machine with an embroidery function, for example, the
There is one described in Japanese Patent No. 3-64994. This machine has an embroidery frame that supports the fabric during embroidery sewing, and is movable in the front-rear direction (X-axis direction) and left-right direction (Y-axis direction) along the top surface of the sewing machine bed. X-
Embroidery stitching is performed by moving it in the Y-axis direction. When sewing this embroidery, the amount of needle thread required to form each stitch differs for each stitch, so in order to form each stitch neatly, it is necessary to adjust the amount of needle thread fed out for each stitch. . For this reason, for example, JP-A-56-31
As shown in Publication No. 788, the amount of needle thread required to form the next stitch is calculated every time one stitch is sewn, and the needle thread pay-out device is driven based on the calculation result to adjust the amount of needle thread required for each stitch. There is one that allows you to pay out only a certain amount.

(Problems to be Solved by the Invention) Even if, as in the conventional configuration, the amount of needle thread required to form the next stitch is calculated every time one stitch is sewn, and the needle thread is paid out according to the calculated value, The amount of needle thread actually required differs depending on the thickness, etc., so there may be slight slack during embroidery sewing, or the tension of the needle thread may increase, and sometimes the stitches may become loose. There is a drawback that the parts are not aligned.

Furthermore, when sewing embroidery, the user must manually move the embroidery frame in the X-Y axis directions to set the initial position. If the upper thread is configured to be paid out in accordance with the movement, if the upper thread is not sewn onto the fabric in advance, not only will the upper thread be unnecessarily paid out during initial settings, but
This causes a large amount of slack in the needle thread in the needle thread path from the needle thread pay-out device to the eye of the sewing needle, resulting in problems such as uneven stitches and the needle thread getting tangled with the thread take-up thread. In this case, if the upper thread is sewn onto the fabric in advance, there is no problem if the embroidery frame can be positioned at the target initial position in the shortest distance, but in many cases, the movement path of the embroidery frame is As a result, the needle thread is unwound more than necessary and becomes loose. In this case as well, the same problem as described above occurs because the needle thread is fed out regardless of the slackness of the needle thread after the start of embroidery stitching.

However, if the upper thread is configured to stop feeding during initial settings, if the upper thread is already sewn onto the fabric, the upper thread will change as the embroidery frame is moved. It has the disadvantage that it is strongly pulled by the fabric, causing thread breakage and bending of the sewing needle.

The present invention has been made in consideration of these circumstances, and its purpose is to maintain the tension of the needle thread appropriately at all times, even during initial setting of the embroidery frame and during the execution of embroidery stitches, so that the stitches are always sewn. To provide a sewing machine with an embroidery sewing function that enables uniform and beautiful embroidery, and prevents the upper thread from becoming entangled with a thread take-up, etc. due to loosening of the upper thread, thread breakage due to excessive tension, and bending of the sewing needle. There is a particular thing.

[Structure of the Invention] (Means for Solving the Problems) The sewing machine with an embroidery sewing function of the present invention has a needle thread feeding device that feeds out needle thread from a needle thread supply source and sends it to a sewing needle, and a needle thread feeding device that feeds the needle thread from a needle thread supply source to a sewing needle, and a needle thread feeding device that supports the cloth during embroidery sewing. and an embroidery frame, in which embroidery stitches are performed by horizontally moving the embroidery frame in synchronization with the vertical movement of the sewing needle, in the middle of the needle thread passing path from the needle thread feeding device to the sewing needle. A tension detecting means for detecting the tension of the upper thread is provided, and when the detected tension of the tension detecting means exceeds a predetermined value, the upper thread unwinding device is operated to let out the upper thread by a predetermined amount. It is composed of

(Function) When initializing the position of the embroidery frame, if the upper thread is sewn onto the fabric in advance, the upper thread will be pulled out from the eye of the sewing needle as the embroidery frame moves, and the upper thread will When the tension becomes greater than a predetermined value, the tension detection means detects this and operates the upper thread pay-out device to pay out the upper thread by a predetermined amount. By repeating such operations, the tension of the needle thread at the time of initial setting is made appropriate. Even in this case, the moving path of the embroidery frame may take a detour due to the user's unfamiliar operations, but if the tension of the upper thread falls below a predetermined value, the upper thread will not be unwound even if the embroidery frame is moved. Therefore, the slack of the needle thread is significantly reduced compared to the conventional method. Moreover, if the tension of the needle thread is less than a predetermined value at the start of embroidery sewing, the needle thread will not be paid out.
Immediately after starting embroidery sewing, the needle thread tension becomes appropriate.

Further, even during execution of embroidery stitching, the tension detection means detects each time the needle thread tension exceeds a predetermined value.
Since the operation of letting out the upper thread by a predetermined amount is repeated, the tension of the upper thread can always be maintained appropriately even if there are differences in thickness.

(Example) Next, one embodiment of the present invention will be described based on the drawings.

First, the overall schematic configuration will be explained based on FIGS. 3 and 4.

A circular embroidery frame 2 is provided on a sewing machine bed 1. This embroidery frame 2 is supported by sandwiching a cloth (not shown) between an inner frame 2a and an outer frame 2b, and is moved in the front and rear directions along the upper surface of the sewing machine bed 1 by an X-Y axis drive device 3. (X
It is movable in the axial direction) and the left-right direction (Y-axis direction). This X-Y axis drive device 3 includes a Y-axis pulse motor 12
A support frame 5 is connected at right angles to the Y-axis spindle 4, and rotation of the Y-axis spindle 4 causes the support frame 5 to move in the left-right direction (Y-axis direction). direction). And, on the lower side of the support frame 5,
An X-axis guide 6 extending in the front-rear direction is fixed, and the embroidery frame 2 is supported on the X-axis guide 6 via a support 10 so as to be slidable in the front-rear direction (X-axis direction). Further, above the Y-axis spindle 4, an X-axis drive rod 7 that is rotationally driven by an X-axis pulse motor 11 (see FIG. 5) is provided in parallel. 9 are spline-fitted so that the rotation of the X-axis drive rod 7 is transmitted to the timing belt 8 via the drive pulley 9. The rotation of the timing belt 8 causes the embroidery frame 2 to slide in parallel in the front-rear direction (X-axis direction) via the support 10.

X-axis/Y-axis pulse motor 1 of such an X-Y axis drive device 3
The operations 1 and 12 are controlled by the control circuit 13 (
5), and when the embroidery frame 2 is initially set, the X-axis and Y-axis pulse motors 11 and 12 are controlled by operating a four-direction frame movement switch 15 provided on the front of the sewing machine arm 14. It is designed to be able to rotate forward or reverse as desired. In order to switch between the manual mode and the automatic embroidery sewing mode by operating the frame movement switch 15, a manual/automatic changeover switch 1 is provided near the manual operation key 15.
6 is provided. Further, on the upper front surface of the sewing machine arm 14, a pattern selection switch 17 for selecting a pattern is provided together with a display section 18 that lights up and displays the selected pattern.
Further, an operation changeover switch 19 is provided for switching between embroidery stitching and normal stitching. Furthermore, a sewing needle 20 and a presser foot 21 are provided on the lower surface of the head of the sewing machine arm 14.

Next, based on FIG. 1, thread the upper thread 22 into a thread spool (not shown).
The configuration for feeding out the sewing needle 20 from the sewing needle 20 will be explained. The needle thread 22 pulled out from the thread spool is first held between thread tension discs 23 installed on the sewing machine arm 14. During operation, the thread tension disc 23 is closed by an electromagnetic solenoid 24 to apply tension to the upper thread 23. An upper thread payout device 25 is provided near the thread tension disc 23. This needle thread pay-out device 25 includes a pay-out roller 27 fixed to the rotating shaft of a pulse motor 26, and a pressure roller 28 that clamps the needle thread 22 between the feed-out roller 27. The pressure roller 28 is supported by one end of a lever 30 that rotates around the lever 29 as a fulcrum, and by pulling the other end of the lever 30 with a spring 31, the pressure roller 28 is pressed against the feeding roller 27.

The upper thread 22 let out from the let-out roller 27 is caught by the hook part 32 and guided to the tension detection means 33 below. As shown in FIG. 2, the tension detecting means 33 includes a key-shaped thread take-up spring 34 on which the upper thread 22 is hooked, a shutter 35 that rotates as the thread take-up spring 34 moves up and down, and a shutter 35. It is composed of an optical sensor 36 whose optical path is opened and closed.

In this case, when the tension of the needle thread 22 exceeds a predetermined value, the thread take-up spring 34 is elastically deformed to the upper limit position shown by the two-dot chain line in FIG. The light sensor 36 rotates to the cut-off position and outputs a detection signal (high level signal) to the control circuit 13 .

This control circuit 13 is equipped with a microcomputer (not shown), and when initializing the position of the embroidery frame 2, the upper thread feeding device and the needle thread feeding device are set according to the control program shown in FIG. 25
The pulse motor 26 of is controlled.

Note that the upper thread 22 pulled out from the thread take-up spring 34 is passed through the eye of the sewing needle 20 via the thread take-up 37.

Next, the operation of the above configuration will be explained. When performing embroidery sewing, a cloth is set in the embroidery frame 2, and the operation changeover switch 19 is switched to the embroidery sewing operation mode. Then, in order to initialize the position of the embroidery frame 2, the manual/automatic changeover switch 16 is switched to manual mode. After that, by appropriately operating the four-direction frame movement switch 15, the X-axis and Y-axis pulse motors 11 and 12 are operated.
The embroidery frame 2 is moved in the X-Y axis direction and set to an arbitrary initial position. If the needle thread 22 has already been sewn onto the fabric before this initial setting, if the embroidery frame 2 is moved,
The needle thread 22 is pulled out from the eye of the sewing needle 20, and the tension of the needle thread 22 increases.

At this time, as shown in FIG. 6, each time the frame movement switch 15 is operated to move the embroidery frame 2 one step (steps Pi, P2), the control circuit 13 moves the embroidery frame 2 up and down based on the output signal of the optical sensor 36. It is determined whether the tension of the thread 22 has exceeded a predetermined value (step P3). Here, the upper thread 22
If the tension is less than the predetermined value, the deformation of the thread take-up spring 34 will not reach the upper limit position shown by the two-dot chain line in FIG.
Since the shutter 35 does not block the optical path of the optical sensor 36, the optical sensor 36 outputs a non-detection signal (low level signal). In this state, the needle thread 22 is not fed out, the embroidery frame 2 is only moved, and the needle thread 22 is not fed out.
Prevent loosening of item 2. After this, by moving the embroidery frame 2,
When the tension of the needle thread 22 exceeds a predetermined value, the thread take-up spring 34 is elastically deformed to the upper limit position shown by the two-dot chain line in FIG. The optical sensor 36 rotates and outputs a detection signal (high level signal).

As a result, the pulse motor 26 of the needle thread pay-out device 25 is energized, the pay-out roller 27 is rotated, and the needle thread 22 is drawn out by a predetermined amount (step P4).

Thereafter, by repeating the above-described operations, the tension of the needle thread 22 at the time of initial setting is set to an appropriate value, thereby preventing thread breakage and bending of the sewing needle 20. Even in this case, the moving path of the embroidery frame 2 may become detoured due to the user's unfamiliar operation, but if the tension of the upper thread 22 becomes less than or equal to the predetermined value, even if the embroidery frame 2 is moved, Since the upper thread 22 is not let out, the slack of the upper thread 22 is significantly reduced compared to the conventional case, and it is possible to prevent the upper thread 22 from becoming entangled with the thread take-up 37.

Moreover, if the tension of the needle thread 22 is less than a predetermined value when starting the embroidery stitch, the needle thread 22 will not be paid out as described later, so the tension of the needle thread 22 will be adjusted to an appropriate value immediately after the start of the embroidery stitch. Become.

In addition, if the upper thread 22 is not sewn onto the cloth at the time of initial setting, even if the embroidery frame 2 moves, the upper thread 22 will not be pulled, so no tension will be applied to the thread take-up spring 34, and the upper thread will not be pulled. The thread 22 is not fed out. Therefore, even in this case, the inconvenience that the needle thread 22 is unnecessarily let out and becomes loose can be prevented.

After the initial settings, to start embroidery sewing, switch the manual/automatic changeover switch 16 to automatic mode, select the desired pattern with the pattern selection switch 17, and operate the operation start switch (not shown). Just do it. As a result, embroidery stitching is automatically started, and embroidery frame 2 is moved in the X-Y direction in accordance with the predetermined pattern data in synchronization with the vertical movement of sewing needle 20, and embroidery stitching is executed. During this embroidery sewing, each time the tension of the upper thread 22 exceeds a predetermined value, the shutter 35 blocks the optical path of the optical sensor 36 due to elastic deformation of the thread take-up spring 34, and the optical sensor 36 sends a detection signal (high level signal ) is output. Each time this detection signal is output, the upper thread unwinding device 25 is operated and the upper thread 22 is reeled out by a predetermined amount. This operation is repeated, and the tension of the upper thread 22 is maintained at an appropriate level.

Therefore, even if there is a difference in thickness, the tension of the upper thread can always be maintained appropriately, and beautiful embroidery stitches with uniform stitches can be performed.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, if the moving path of the embroidery frame 2 becomes a detour during initial setting and the upper thread 22 becomes slack, the upper thread unwinding device 25 may be The slack in the upper thread 22 may be removed by rotating the pulse motor 26 in the reverse direction.

In addition, the present invention can be modified in various ways, such as the tension detection means 33 may be configured with a strain gauge, a weight sensor, or the like.

[Effects of the Invention] As is clear from the above description, the sewing machine with an embroidery sewing function of the present invention includes a tension detection means for detecting the tension of the needle thread in the middle of the needle thread passing path from the needle thread feeding device to the sewing needle. is provided, and when the tension detected by the tension detection means exceeds a predetermined value, the needle thread feeding device is operated to feed out the needle thread by a predetermined amount. Even during execution, the tension of the upper thread can always be maintained appropriately, making it possible to always perform beautiful embroidery with uniform stitches, and also prevent the upper thread from getting tangled with the thread take-up due to loose needle thread, or from excessive tension. This has the excellent effect of preventing thread breakage and bending of the sewing needle.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic front view of the main parts, Fig. 2 is an enlarged front view of the tension detection means, Fig. 3 is a perspective view of the whole, and Fig. 4. 5 is a plan view of the sewing machine bed, FIG. 5 is a block diagram of the control system, and FIG. 6 is a flowchart showing the flow of control. In the drawing, 1 is a sewing machine bed, 2 is an embroidery frame, 3 is an X-Y axis drive device, 4 is a Y-axis spindle, 6 is an X-axis guide, 7 is an X-axis drive rod, 8 is a timing belt, and 11 is an X-axis pulse Motor, 12 is a Y-axis pulse motor, 13 is a control circuit, 14 is a sewing machine arm, 15 is a frame movement switch, 20 is a sewing needle, 22 is an upper thread, 23 is a thread tension disc, 25 is an upper thread feeding device, 26 is a pulse Motor, 27 is a feeding roller, 33
34 is a tension detection means, 34 is a thread take-up spring, 35 is a shutter, 36 is a light sensor, and 37 is a balance. Agent Patent Attorney Tsuyoshi Sato Figure 51!1 Figure 51!

Claims (1)

[Claims] 1. The embroidery frame is equipped with a needle thread feeding device that feeds the needle thread from the needle thread supply source and sends it to the sewing needle, and an embroidery frame that supports the cloth during embroidery sewing, and the embroidery frame is moved horizontally in synchronization with the vertical movement of the sewing needle. In a sewing machine with an embroidery function configured to perform embroidery sewing, a tension detection means for detecting the tension of the needle thread is provided in the middle of the needle thread passage path from the needle thread feeding device to the sewing needle, and the tension detection means detects the tension of the needle thread. 1. A sewing machine with an embroidery function, characterized in that the needle thread pay-out device is operated to pay out a predetermined amount of the needle thread when the detected tension exceeds a predetermined value.