JP2800976B2 - Sewing thread tension detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine thread tension detecting device for detecting a lower thread tension of a sewing machine.

[Conventional technology]

As is well known, in a sewing machine, the quality of a sewing state largely depends on whether or not the tension of a lower thread at the time of sewing is properly set. Further, since the proper tension of the bobbin thread varies depending on the type of the sewing product or the thread, it is necessary to perform the tension detection setting every time the bobbin thread tension is changed.

Conventionally, a yarn tension detecting device 1 as shown in FIG. 4 has been used for detecting the upper and lower yarn tensions. The thread tension detecting device 1 hooks the end of an upper thread or a lower thread supplied from an upper thread and a lower thread supply source (a bobbin 1c and a bobbin not shown) of the sewing machine to the detecting unit 1a, and in this state, The scale 1b is read while pulling the device in a certain direction.

After the thread tension is detected by the detecting device 1, the adjusting dial of the thread tension plate 3 provided on the sewing machine arm 2a is adjusted.
3a, or by turning the tension adjusting screw 4a of the bobbin case 4 mounted in the sewing machine bed 2b (the bobbin case 4 is fitted in The thread drawn out from the bobbin bobbin
4b, the distance between the thread presser spring 4c and the outer peripheral surface of the bobbin case 4 is adjusted. (See Fig. 5) Adjust the tension of the upper thread I1 and the lower thread I2.

[Problems to be solved by the invention]

However, in the above-described conventional yarn tension detecting device, it is extremely difficult to read the scale 1b because the worker performs the reading while pulling the device itself in a certain direction together with the yarn and performs reading. In other words, the value that the scale aims at greatly changes depending on the angle (pulling direction) at which the yarn of the device 1 is pulled out, so that it is difficult to always read the device 1 in the same state in order to read an accurate value. is there. In particular, the tension adjustment of the bobbin thread is performed based on the detected tension, and the operator tightens or loosens the tension adjustment screw 4a. You need to repeat the work you said. For this reason, in the above-described device, every time the detection operation is repeated, it is necessary to remove the yarn from the detection unit, or to pull and measure the device while pulling the drawn long yarn, Workability was extremely low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a yarn tension detecting device capable of accurately and easily detecting a lower thread tension.

[Means for solving the problem]

In the sewing machine thread tension detecting device according to the present invention, a bobbin case having a bobbin around which a bobbin thread is wound is detachably provided on a support member 10 and the bobbin case 4 provided on the support member is fixed near a lower thread outlet. A tension meter 11 having a first thread guide 13, a pointer 11c, and a detection lever 11b having a thread hook 11d fixed at the tip.
And a second thread guide 14 fixedly arranged on the support member at a predetermined distance from the first thread guide 13. The lower thread coming out of the bobbin case receives the first thread guide 13, the thread hooking portion 11d, and the second thread guide. In a state where the lower thread is sequentially wound over the lower thread 14, the bending angle of the lower thread that is stretched between the first thread guide, the thread hooking section, and the second thread guide is substantially constant by the vertical movement of the thread hooking section of the detection lever. The first yarn guide, the yarn hooking portion, and the second yarn guide are arranged at a position where the acute angle is maintained.

[Action]

When the thread tension is detected by the thread tension detecting device of the sewing machine according to the present invention, the operator first passes the lower thread pulled out from the bobbin case to the first thread guide 13 and the thread hooking section 11d, and then the first thread. Guide the lower thread drawn from guide 13 to the second thread guide
Pull outward from 14. This allows the tension meter to display the thread tension applied to the thread hooking portion, thereby greatly improving work efficiency.

Further, since the first and second thread guides are fixed to the support member and are kept constant, it is possible to always perform appropriate tension detection.

(Example of the invention)

 Hereinafter, embodiments of the present invention will be described.

1 to 3 show an embodiment of the present invention.

In the drawing, reference numeral 10 denotes a mounting plate (supporting member), and a suction portion such as a magnet is provided on a bottom surface thereof as necessary. Reference numeral 11 denotes a tension meter (tension meter) fixed to the upper surface of the mounting plate 10. The tension meter 11 is displaced by pressing a detection lever 11b protruding from the main body member 11a. The displacement value applied to the detection lever 11b is indicated. 11d is the detection lever 1
The hook-shaped thread hooking portion provided at the tip of 1b, 11e is the main body member 1.
The scale plate (display means) provided in 1a is shown.

Reference numeral 12 denotes an inner pot as a holding body detachably mounted on the upper surface of the mounting plate 10. The inner hook 12 is exactly the same as that used in a normal sewing machine, and can be replaced with another one of another size and type as needed.

Reference numerals 13 and 14 denote two hook-shaped first and second thread guides for guiding the lower thread.

In the embodiment having the above configuration, the tension of the lower thread I2 is detected as follows.

First, the bobbin is taken out together with the bobbin case 4 from the inner hook (not shown) of the sewing machine stored in the sewing machine bed 2b (see FIG. 4), and these are taken out of the inner hook 12 provided on the mounting plate 10.
Attach with the specified mounting method. Next, the lower thread I2 led out from the lower thread drawing groove 4b of the bobbin case 4 as a thread tension setting member is passed over the first thread guide 13, the thread hooking section 11d and the second thread guide 14, and the second thread While traversing the thread derived from the guide 14 with both hands, check the scale to be inserted by the pointer 11c.

Thereafter, until the tension of the bobbin thread I2 reaches a required value, the adjustment operation using the tension adjustment screw 4a of the bobbin case 4 and the above-described detection operation are repeated.

As described above, in this embodiment, the tension meter (tension meter) 11 is fixed to the sewing machine arm 2a via the mounting plate 10, so that the operator can read the scale accurately and use both hands. Since the yarn can be moved, the operation can be performed very easily.

Regardless of the position where the worker performs the thread picking operation, the positions of the first and second thread guides 13 and 14 are kept constant, and the measurement is performed by measuring the vertical movement of the tension meter. Therefore, the bending angle of the thread coming out of the thread presser spring 4c of the bobbin case can be kept substantially constant, and proper tension detection can be always performed.

In the above embodiment, if the detection lever 11b of the tension meter (tension meter) 11 is held by air or an oil damper D as shown in FIG. The delicate swing of the thread hook 11d can be absorbed by the damper D, and the value indicated by the needle finger 11c can be read more accurately.

FIG. 3 shows a tension adjusting screw driving mechanism B.
This mechanism B is provided with a tension adjusting screw 4a of the bobbin case 4 as a thread tension setting member mounted on the mounting plate 10 at the east side.
It comprises a driver member 48 movably held up and down so that it can be fitted and disengaged, and a pulse motor 49 for rotating the driver member 48. The pulse motor 49 is fixed to the mounting plate, and the pulse motor 49 May be driven.

〔The invention's effect〕

As described above, according to the present invention, it is possible to quickly and easily detect an accurate lower thread tension, greatly improve work efficiency, and always provide an appropriate thread tightness to a stitch. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a plan view showing a state where a damper is added, FIG. 3 is a perspective view showing an adjusting screw driving mechanism, and FIG. FIG. 5 is a perspective view showing the apparatus, and FIG. 5 is a side view showing a bobbin case. I2 ... bobbin thread 11 ... tension meter (tension meter) 11b ... detection lever 11c ... pointer 11d ... thread hooking section 13 ... first thread guide 14 ... second thread guide

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-224786 (JP, A) JP-A 55-79987 (JP, U)

Claims (1)

(57) [Claims] 1. A support member 10 having a bobbin case 4 having a bobbin wound with a bobbin thread detachably provided thereon, a first thread guide 13 fixed near a bobbin case lower bobbin outlet provided on the support member. A pointer 11c, a tension meter 11 having a detection lever 11b which moves vertically and has a thread hook 11d fixed at the tip thereof, and a second thread guide 14 fixedly arranged on a support member at a predetermined distance from the first thread guide. When the bobbin thread coming out of the bobbin case is sequentially passed over the first thread guide, the thread hooking section, and the second thread guide, the lower thread is hooked on the first thread guide, the thread hooking section, and the second thread guide. The first yarn guide, the yarn hooking portion, and the second yarn guide are arranged at positions where the bending angle of the passed lower thread maintains an almost constant acute angle even when the detection lever moves vertically in the yarn hooking portion. A thread tension detecting device for a sewing machine.