JPH01300988A - Needle thread feeding device for 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 [Industrial Application Field] The present invention relates to an upper thread supply device for a sewing machine, which is related to an upper thread automatic correction technology for pitch errors in a sewing machine. [Prior Art] In particular, for industrial sewing machines , sewing is carried out over a wide range of rotational speeds from very low speeds to high speeds, but when sewing with a sewing machine, the amount of fabric fed is larger at high speeds than at low speeds, which is called "pitch error J." However, since the needle thread supply mechanism of conventional sewing machines is structured to supply the same amount of needle thread at low and high speeds,
As shown in the figure, when the feed amount increases at high speeds (see b), the knotting point N of the δ-thick stitch moves to the upper side of the fabric, which actually has the disadvantage of causing uneven tightness at high and low speeds. .

Therefore, as a mechanism for managing the amount of needle thread let out in response to this pitch error, the thread is let out with an auxiliary thread take-up consisting of a thread collapse lever with a constant operating stroke, and the amount of let out is controlled with an encoder. Controlled by the 0N10FF timing of the solenoid, or the auxiliary balance (seambu), which unwinds the thread with a roller, and the encoder and sole that detects the rotation tJ. Those controlled by 0N10FF-timing are not used.

151 Problems to be Solved] That is, regarding the pitch error. The mechanism for solving uneven tightening and the conventional one are based on the sewing speed of the sewing machine.
The present invention has been made in view of the above-mentioned problems.

In addition to its simple structure, it has a structure that automatically responds to changes in the system's supply amount or fabric feed rate, and allows the needle thread of the sewing machine to produce beautiful stitches with uniform tightness at high and low speeds. supply'! It is [1 purpose] to provide Am.

[Means for solving the problem 1 - The thread feeding device of the sewing machine related to []
Take the needle bar Lfi movement (L shaft mounting 1)
, 71jj Along with the pickpocketing, in a diagonal feed rimming machine that tilts and moves the needle bar, the -1- system is supplied to the sewing machine side (along -2 along the heavy thread path of f), and the -1- system is The first thread holding stage and the second thread holding means are configured to be restrained or released in response to a control signal corresponding to the rotation angle of the needle bar swing shaft, and the yarn path between the two thread holding means is traversed. The invention comprises an auxiliary take-up lever having a thread pay-out lever that moves forward and backward to create slack in the upper thread, and the auxiliary take-up is structured to swing back and forth using the four rods 11 and the moving shaft as a driving source. That is.

Also, the first yarn holding means and the second yarn holding means (, [, respectively, a solenoid coil and a magnetized by the excitation of the solenoid coil, 771), ]-system are held together'? :) Consists of a clamping board.

[Operation] Therefore, when setting the upper thread supply, the auxiliary thread take-up is oscillated with the second thread holding stage of the thread path closed, and the needle thread that has been formed "τ" is The slack is set as the supply amount for that time, and the first thread holding means is closed and the second thread holding means is opened to supply the first thread, and the drive source of the auxiliary balance is Since it is taken from the needle bar swing axis, the movement of the thread pay-out lever becomes proportional to the inclination angle of the needle bar, and the thread supply rate changes automatically in accordance with the fabric feed rate. Therefore, pitch errors caused by differences in sewing speed are automatically changed in accordance with the amount of needle thread supplied or the amount of cloth fed, so that uneven tightness of the seams does not occur.

[Embodiment] Hereinafter, an embodiment of a -J-thread supply device for a sewing machine related to unsewn Ijl will be described with reference to the drawings.

1 and 2 illustrate the principle IA of the main parts of a needle feed sewing machine.

Sewing machine l has a side bar swing shaft 2 that swings back and forth in conjunction with the drive source.
Attach the sewing machine hook 4 to the tip end of the needle bar 3, which is pivoted on the
(It is equipped with a take-up lever 5 that is linked to the vertical movement of the side bar 3, and a 1-system control mechanism is configured in the thread path of the sewing thread 1' between the bobbin 6 of the needle thread supply source of the sewing machine and the take-up thread 5. ) becomes.

Reference numeral 7 denotes an auxiliary head (f) which is protruded from the needle bar swing shaft 2 so that the thread let-out lever 10 moves up and down between the thread guides 8 and 9 arranged in the thread path. The vertical movement (arrow A) of the auxiliary take-up lever 7 or the needle bar 3 is caused by the 4-feed of the needle bar 3 (arrow B) and the i!I! movement, and the needle bar swing axis 20
It moves up and down in proportion to the rotation angle.

A first thread holding means 11 and a second thread holding stage 12 are provided in the +iii side thread path and the rear thread path of the auxiliary thread take-up 7, respectively, to restrain or release the upper thread T. Holding means 11
．． 12 respectively energize or de-energize the solenoid coils 13 and 14 to magnetize the clamping plates 15 and 16. "F Drive and pass" - The thread T is twisted as shown in FIG.

Note that the reference numeral qt7 in FIG. 1 indicates a thread guide arranged as appropriate, and constitutes a thread path for the thread T passing through the needle hole of the sewing machine needle 4.

In the cloth feeding device of the sewing machine having the above configuration, the sewing machine needle 4 that pierces the pattern is displaced by the cloth feeding operation, and the needle bar 3 is tilted (arrow B) in conjunction with the amount of displacement. The auxiliary thread take-up lever 7 of the needle thread supply device has a structure that is integrated with the needle bar 3 via the needle bar swing shaft 2, so the thread pay-out lever lo of the auxiliary thread take-up lever 7 that protrudes into the thread path is connected to the needle bar swing shaft 2. Moving axis 2
It has a vertical amplitude 9 (arrow A) proportional to the rotation angle of .

As a result, when the amount of cloth feed is changed, the amplitude of this auxiliary take-up lever 7 is automatically changed, and a predetermined amount of thread T is paid out, and the feed speed is also corrected for pitch errors caused by fluctuations in the sewing speed mentioned above. Since the amplitude of the auxiliary balance 7 is determined in accordance with the amount, uneven tightening will not occur.

Next, the needle thread supplying operation of the needle thread supplying device having the above-mentioned structure will be explained with reference to the solenoid coil operation diagram in FIG. 4 while referring to the diagram for explaining the operation timing of the solenoid coil in FIG. 3.

(a) Let the top dead center of the needle bar 3 be Oo.

For timing near 0°, both solenoid coils 13.1
4 are both in the ONN state, the first and second thread holding means 11
．． 12 closes the thread path and clamps the upper thread T, so the auxiliary thread is closed! The upper thread T let out by +'7 is thread guide 8.9
It is in a relaxed state as it is stretched out between.

(b) When the solenoid coil 14 of the second thread holding means 12 is turned off at about 40 degrees, the thread guides 8 and 9
The slack in the upper thread T between the threads is released to the thread take-up side.

(c) In the vicinity of 60°, the thread T between the thread guides 8 and 9 is supplied to the thread take-up lever 5 due to the operation of the thread take-up lever 5.

(d) The above-mentioned supply of the upper thread T ends when the top dead center of the thread take-up 5 reaches approximately 70 degrees.

(e) When the solenoid coil 14 of the second thread holding means 12 is turned on at the 80° position, the needle thread T is held on the thread take-up side 5.

(f) At about 180°, when the solenoid coil 13 of the first system holding means 11 is turned off, only the upper thread T can be let out.

(g) In the vicinity of 22°, the thread pay-out lever lO of the auxiliary thread take-up lever 7 is lowered to pull down the needle thread T between the thread guides 8 and 9, whereby the needle thread T is paid out.

(h) At the 270° position, the auxiliary balance 7 is at its lowest point (
This lowest point is displaced in proportion to the inclination angle of the needle bar 3. )
is reached, and the feeding of the upper thread T is completed, and the upper thread T
The solenoid coil 13 of the first system holding means 11 is turned ON and the needle thread T is held in the state in which the needle thread T is kept being let out.

Thereafter, the operation returns to the above (a) and repeats the cyclic operation.

The amount of upper thread T that is paid out by the operations (a) to (h) above is determined by the relationship between the lowest point position of the thread guide 8.9 and the thread pay-out lever 10 of the auxiliary thread take-up lever 7. As described above, this positional relationship is determined by the swing axis of the thread pay-out lever lO, and therefore changes depending on the feed amount of 4+ and the pitch error. In addition, since this amount of let-out can also be changed by changing the relative position of the thread guide 8.9, an upper thread tension adjustment mechanism is constructed in which the position of the thread guide 8.9 is variable. '+- can also happen.

[Effects of the Invention] As described above, in the needle thread supply device of the sewing machine according to the present invention, since the drive source of the auxiliary thread take-up is taken from the needle bar swing shaft, the amount of two threads supplied is equal to the fabric feed. In addition to automatically changing according to the amount of pitch, it also automatically changes in response to pitch errors caused by differences in high and low speeds.
It is possible to form beautiful seams without uneven tightness at high and low speeds with a very simple structure that does not require a mechanism such as an encoder, and the effects of implementing the present invention are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of a sewing machine head section showing an embodiment of the needle thread supply device of a sewing machine according to the present invention, and FIG. Figure 3 shows a theory showing the operation timing of the solenoid coil [51[, 2I, Figures 4 (a) to (Th
) is an explanatory diagram showing the operation of the solenoid 1-1, and FIG. 5 is a diagram illustrating the pitch error phenomenon showing &i[i] at low speed (a) and high speed (b). 1-Sewing machine 2-J axis for sewing 3-Needle bar
4-1 sewing machine needle 5 - balance 6 - bobbin winder 7 - auxiliary thread take-up 8.9 - thread guide 10 - thread payout 1 lever 11 - first system holding means 12 - first system holding means 1: I,
14 ~ Solenoid coil T ~ Upper thread 1985 5yI El Patent applicant Tee, - “ -■ Co., Ltd. No. 1 Fig. 3 Fig. 4

Claims (1)

[Claims] (1) In a needle-feed sewing machine in which the needle bar to which the sewing machine needle is attached is pivoted to a needle bar swing shaft, and the needle bar is tilted in response to fabric feed, the thread in the front stage of the take-up thread that supplies the needle thread to the sewing machine needle is used. Along the path, a first thread holding means and a second thread holding means are configured to restrain or release the needle thread according to a control signal corresponding to the rotation angle of the needle bar swing axis, and a thread holding means is formed between the two thread holding means. The auxiliary take-up lever has a thread take-up lever that moves forward and backward across the thread path to create a slack in the upper thread, and the auxiliary take-up is reciprocated using the needle bar swing shaft as a drive source. A needle thread supply device for a sewing machine, characterized by having a structure in which: