JPS6019278B2 - Automatic thread tightening regulation control device using a thread take-up - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic control device for regulating thread tightening using a thread take-up, which is capable of automatically adjusting the amount of needle thread supplied so that a good second stitch can always be obtained in sewing work using a sewing machine. It is.

Conventionally, in order to make good stitches on a sewing machine, the tension of the upper thread is adjusted by adjusting the spring pressure of the tension disc to adjust the tension balance between the upper thread and the lower thread, and then the thread take-up is used to pull up the lower thread and pull out the upper thread. However, it was necessary to perform trial sewing to adjust the spring pressure of the tension valve so that a good sewing could be performed, and the adjustment was not easy.

In place of the conventional thread tension disc, the present invention provides a fixed needle thread tension device or a needle thread gripping device that applies a base tension to the needle thread to the extent that the upper thread is sewn. A magnetic upper thread gripper is provided to grip the upper thread, and the upper thread is gripped when the intersecting point of the upper thread and lower thread is pulled up to the middle of the sewing fabric by the upper thread pulling action of the thread take-up, and the lower thread is pulled up by the thread take-up. At the same time as the pulling is stopped, the needle thread is pulled out from the needle thread bobbin by the thread take-up, the length of which has been consumed for suturing.

Furthermore, an encoder with a pulley is installed to measure the amount of needle thread that is fed out, and the theoretical length of the needle thread required for suturing (including the amount of correction) is compared with the length of the thread that is actually fed out. The present invention attempts to correct the gripping timing of the magnetic needle thread gripper to correct errors caused by elongation of the needle thread due to rapid lifting of the thread take-up. Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a cross-sectional view when sewing two pieces of cloth together, and the needle thread length required when sewing two pieces of cloth with a thickness of d is the length of the upper and lower threads that is located between the two pieces of cloth. If the stitch pitch is P, then it will be P12d. By the way, the needle thread take-up characteristic by the thread take-up is unique to the sewing machine and is as shown in Figure 2 A. If the upper thread is started to be fed out at the time t when the upper amount reaches P, the thread take-up will be at the top dead center 0 and the end of the thread line will be soft. By the balance P
More than ten lengths of needle thread will be paid out. The thread take-up characteristics of the thread take-up thread are inputted to a control console built into the sewing machine. Taking advantage of this, a tension pupil (base tension device) is provided to apply tension to the upper thread to the extent necessary for top suspension stitching, and the upper thread tension is made larger than the lower thread tension, and by the needle thread take-up action by the thread take-up, When the intertwining point of the needle thread and bobbin thread is pulled up and reaches the middle position of the sewing fabric, in other words, when the thread take-up should start pulling out the needle thread to P + phantom length, the "between the thread take-up and the sewing needle" When the upper thread is gripped and fixed, the upper thread is then pulled out by P0 from the upper thread bobbin side by the action of the thread take-up.

In other words, this means that good stitching was performed and the amount of needle thread consumed was paid out from the needle thread bobbin by the thread take-up action. Furthermore, if a device for measuring the amount of thread actually pulled out is installed, and this is compared with the standard value (including the correction amount), and the operation timing of the upper thread gripper is corrected, the thread take-up can be adjusted. It is possible to correct errors caused by elongation of the needle thread due to the action. In FIG. 3, the sewing machine 1 is provided with a fixed needle thread tension bag 2 that gives tension to the needle thread for upper hanging stitching in place of the conventional needle thread tension disc, and also has a thread take-up lever 3. An electromagnetic needle thread gripper 5 is provided between the needle 4 and the needle 4, and the needle thread 6 is held in place by a guide 8, a needle thread tension device 2, and a guide which also applies a weaker tension than the bobbin winder 7 to the extent that the needle thread is not disturbed. 9, a thread take-up 3, and an electromagnetic upper thread gripper 5 which is clamped by two plates, and is guided to the needle 4.

In the process of picking up the needle thread 6 to which tension is applied by the needle thread tensioning device 2 to a strength sufficient to create a top-hanging stitch, the needle thread gripper 5 uses the thread take-up 3 to intertwine the bobbin thread with the needle thread and pull it up. When the interlacing point reaches the middle of the cloth, that is, the position of good warp, it operates to pinch the upper thread 6 and hold it so that it does not move.
Then, the intersection point of the needle thread and the bobbin thread will stop in the middle of the overall fabric, and due to the pick-up action of the thread take-up thread, the needle thread will be pulled out from the bobbin winder 7 via the needle thread tension device 2. At the dead center, as explained earlier, it will have been extended by the length of p ten phantoms. In other words, due to the needle thread take-up characteristic of the thread take-up, if it is desired to take out the needle thread of length p12d, it is only necessary to start supplying the needle thread at a later time, as shown in the opening of Figure 2. At that time, if the needle thread is gripped and fixed between the thread take-up 3 and the needle 4, the thread take-up action of the thread thread take-up will cause the needle thread amount P+phantom to be let out by the thread take-up. The needle thread gripper 5 may be released again at an appropriate time after the top dead center of the balance to has passed.
By the way, if a sufficient tension is applied to the needle thread to create a top-hung stitching state, a strong force will be applied to the needle thread when the thread take-up action of the thread take-up is performed, and a phenomenon will occur in which the needle thread will be stretched.

In order to correct this, as shown in FIG. The measured value is compared with the reference value (including the correction amount) obtained from the thread take-up curve of the needle thread take-up, and the operation timing of the needle thread gripper is shifted by the amount of the increase. Fig. 5 shows another embodiment of the present invention, in which the needle thread stretches when a strong tension is applied to it, so a large force is applied to the needle thread for the necessary period, and when the needle thread is let out from the bobbin spool 7 by the thread take-up, the needle thread is stretched. It is designed to remove the pressure applied to the

That is, in place of the fixed upper thread tension device 2 in FIG. 3, a second electromagnetic upper thread gripper 11 similar to the upper thread gripper 5 is provided, and the upper thread gripper 5 is not operated. The thread gripper 11 is activated. In this way, the thread winding 7 by the balance
When pulling out the twisted thread, the upper thread gripper 11 does not grip the upper thread, so almost no tension is applied to pulling out the upper thread, and the thread take-up 3 pulls up the intertwining point of the upper thread and lower thread. In this case, the needle thread gripper 5 is open (inoperative) and the needle thread gripper 11 is closed (activated) (which can also be considered as a state in which the maximum tension is applied to the upper thread), so the thread take-up The intersection point of the needle thread and bobbin thread is reliably pulled up, and when it reaches the middle of the stitched fabric, the needle thread gripper 5 is closed, and the needle thread gripper 11 is opened instead, and the needle thread is pulled up by the thread take-up. , the pulling up of the bobbin thread at the interlacing point is stopped, and the thread thread take-up action from the bobbin take-up is performed, and the amount of thread consumed in the first stitch is paid out. As explained above, the present invention allows the sewing work to be performed under conditions that can result in overhang stitching, that is, under sewing conditions such that the intertwining point of the upper thread and lower thread is on the upper surface of the sewing cloth, and the upper thread and lower thread When the intertwining point reaches the middle of the sewn fabric, the thread take-up stops the thread take-up and only pulls out the upper thread from the bobbin winder. It stays in the middle of the stitched fabric and provides good stitching.

Note that a computer may be used to control the upper thread gripping device when the thread take-up position by the thread take-up lever is P+2d.

In other words, the fabric thickness is determined by detecting the amount of vertical movement of the fabric pressing device, the stitch pitch is determined by setting the sewing machine stitches, and P+phantom is determined.
Furthermore, since the thread take-up characteristic of a sewing machine is unique to that sewing machine, this is stored in the computer, and the time to operate the electromagnetic needle thread gripper is calculated and controlled by inputting the above P+2d. Just do it like this. As described above, according to the present invention, it is possible to obtain a sewing machine with a simple configuration that can automatically achieve good stitching, which has conventionally been considered difficult.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view along the seam of the suture cloth, Figure 2 A is a diagram showing the needle thread take-up curve by the thread take-up, and the figure is a partially enlarged view.
FIG. 3 is an explanatory diagram showing an embodiment according to the invention, FIG. 4 is a diagram showing another embodiment of the invention, and FIG. 5 is a diagram showing another embodiment of the invention. 1... Sewing machine, 2... Fixed needle thread tension device, 3... Balance, 4...
・Sewing needle, 5... Electromagnetic needle thread gripper, 10... Thread output amount detector, 11... Second needle thread gripper, P... Stitch pitch, d... One piece of cloth Thick. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. The sewing work is performed under conditions in which the upper thread is controlled so that the stitches are suspended stitches, and between the thread take-up thread and the sewing needle, the upper thread and lower thread are When the intertwining point of the threads has been pulled up to the middle position of the sutured fabric, an electromagnetic system is created by sandwiching two plates to grip the upper thread and stop the pull-up of the lower thread by the thread take-up, and at the same time perform the action of paying out the upper thread. An automatic control device for regulating thread tightening using a thread take-up, which is equipped with an upper thread gripper. 2. A thread payout amount detector is installed between the needle thread bobbin and the fixed needle thread tension device to measure the thread amount pulled out from the needle thread bobbin by the action of the thread take-up, and compare this with the reference value (including the correction amount). An automatic thread tightening regulation control device using a thread take-up according to claim 1, wherein the operating timing of the upper thread gripper is corrected and controlled by comparison. 3. In order to make the stitches into a top-hung stitch, a second needle thread grasper similar to the needle thread grasper provided between the thread take-up and the sewing needle is provided between the thread take-up and the thread winder. The thread tightening regulation automatic control device using a thread take-up recited in claim 1, wherein the needle thread gripper operates to grip the needle thread only while the needle thread gripper between the thread take-up and the sewing needle is not operating. .