JPH0366915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thread take-up device for a sewing machine that can automatically thread the thread.

It is known to have a slit-like introduction groove leading to the thread hole in order to facilitate the threading of the thread into the thread take-up. Because of this, if the introduction groove opening is inside the frame, or even if it is exposed outside the frame, if it is near the frame, the frame will get in the way and make it difficult to thread the thread. Normally, the above operation is performed near the top dead center where the balance protrudes the most outside the frame, so it is also necessary to operate a pulley to place the balance in this position.

This invention attempts to eliminate the above-mentioned work for threading by automatically threading the thread by guiding the thread to the thread hole by the movement of the thread take-up.

The figure shows one embodiment of the present invention, in which a gear (not shown) and a balance weight 3 are fixed to a main shaft 1, and the former gear meshes with a gear coaxial with a drive pulley 4 to rotate the drive pulley 4. , drive pulley 4
The driven pulley 5 is rotated via an endless belt, preferably a timing belt 6, which is hung between the driven pulley 5 and the driven pulley 5, which is rotatably supported on the frame, and a needle bar 7 is further connected to the driven pulley 5 by a rod 8. As is known, the needle bar 7 is moved up and down by the rotation of the driven pulley.

On the other hand, a bell crank 10 is pivoted to the latter balance weight 3, one arm of the bell crank is pivoted to a lever 11 that is pivoted to the frame, and the other arm is pivoted to a connecting rod 12. Furthermore, a balance 14 is connected to the side plate 13 by a pin 16 passed through a horizontal hole 15 bored in the side plate 13, and a pin 17 that fits into the horizontal hole is attached to the middle part of the balance. , 17 are slidably fitted into the horizontal hole 15, so that the balance 14 is reciprocated along the horizontal hole 15 by the rotation of the balance weight 16. The thread hole 18 of the thread take-up thread is formed in the shape of a long hole, and as shown in FIG. The guides (the figure shows a thread tension spring 2 as a guide) are arranged on the front side of both tongue pieces, that is, on both sides of the thread take-up lever 14.
2 and a thread 2 hung over a guide pin 23 (although other known guides may be used)
The tongue piece 20 closer to 4 is formed to be inclined or curved obliquely backward, and when the balance 14 moves forward, the thread 24 engages with and slides on the tongue piece 20, is pushed out from the tongue piece, and finally comes off. ing. Rear tongue piece 21
protrudes longer than the tongue piece 20 on the front side, and the tongue piece 2
A tapered inlet 19 is formed between the inlet 19 and the tongue 20, and is preferably inclined or curved toward the front in a symmetrical shape with the tongue 20, so that as the balance moves forward, it comes off from the front tongue. The thread is formed so that it can easily slide toward the rear of the tongue piece 21 after engagement.

Next, threading the thread into the thread take-up will be explained in detail with reference to Figs. 4A to 4H. When the thread take-up 14 moves forward (Fig. 4A), the tongue piece 20 on the front side engages with the thread 24 and pushes it out (Fig. 4B). figure). The extruded thread 24 comes off the tongue piece 20 and engages with the tongue piece 21 on the rear side (FIG. 4C).
Next, the thread slides on the tongue piece 21 and is pushed out toward the front side, and eventually is located behind the thread hole 18, and is passed through the thread hole 18 and swells toward the front side (FIG. 4D).
When the balance 14 finishes advancing and retreats (Fig. 4E),
The thread moves relatively between the thread holes and comes to be located in front of the thread hole (Fig. 4E).
1, the bulge is eliminated, and the tongue piece 20 on the front side protrudes from the thread in this state even when the bulge is eliminated and it extends straight between the two guides, and is formed to be inclined or curved. The thread engaged with the tongue piece 20 slides on the tongue piece 20 and is pushed out to the front side again and becomes in a swollen state, and does not come out from the introduction hole 19.

To prevent the thread from coming out of the introduction hole 19, insert both tongue pieces 20 and 21 into the horizontal hole 15 as shown in FIG.
It would be more secure and desirable if it could be fitted and slid.

The fitting of the rear tongue piece 21 into the horizontal hole 15 also prevents the thread that has come off the front tongue piece 20 from getting over the rear tongue piece 21 when the balance moves forward. There is an advantage that the amount of protrusion of the tongue piece 21 can be reduced. When the thread take-up 14 moves further back than the state shown in Fig. 4F, it pulls the thread between both guides backwards (Fig. 4G), thereby reeling in the thread, and when the thread take-up is moved back the most, the maximum thread is reeled in. (4th H
figure).

Note that the presser foot 27 attached to the presser foot bar 26 is pressed against the throat plate 29 by a spring 28, like the known one, and is lifted onto the throat plate by downward operation of the presser foot lifting lever 30. .
In the figure, 32 is a thread tension device.

In the embodiment described above, the thread take-up engages the vertical thread hung on the upper and lower guides and captures the thread in the thread hole, but in another embodiment, the thread is threaded on the guides arranged on the left and right. It is hung horizontally, and the balance is also tilted 90 degrees to the front or away from the one shown, and can be moved back and forth laterally, or even vertically, by a mechanism similar to the embodiment shown. It moves diagonally up and down. When the thread is hung horizontally, if the thread hole of the conventional thread take-up mechanism is configured in the same way as in the above embodiment, threading through the thread hole can be performed in the same manner as described above with the conventional thread take-up mechanism. .

As described above, the thread take-up device of the present invention can thread the thread into the thread take-up by simply reciprocating the thread take-up after hooking the thread onto the guides arranged on both sides of the thread take-up path. Therefore, the work of operating the thread take-up near the top dead center and threading the thread can be omitted.

[Brief explanation of drawings]

Figures 1 and 2 are side views of the main mechanism of a sewing machine equipped with a balance device according to the present invention, with Figure 1 showing the state when the take-up lever moves forward, and Figure 2 showing the state when it moves backward. There is. FIG. 3 is a plan view of the main part of the thread take-up device, and FIGS. 4A to 4H are plan views of the main part of the thread threading procedure. 1...Main shaft, 3...Balance weight, 10...
... Bell crank, 11 ... Lever, 12 ... Connection rod, 13 ... Side plate, 14 ... Balance, 15 ... Horizontal hole, 16, 17 ... Pin, 18 ... Thread hole, 19 ...
...Introduction port, 20, 21... tongue piece, 24... thread.

Claims (1)

[Scope of Claims] 1. A mechanism for reciprocating the thread take-up 14 laterally or vertically in conjunction with the main shaft 1, and threading guides 2 disposed on both sides of the path along which the thread take-up 14 reciprocates.
2, 23, and a thread hole 18 formed in the thread take-up 14,
A pair of tongue pieces 20, 2 formed to protrude from the balance 14
1, and has an entrance 19 communicating with the thread hole 18, and of the pair of tongues 20, 21, the first tongue 20, which is closer to the thread, is connected to both sides when the thread take-up 14 moves forward. The thread 24 between the guides 23 and 23 is engaged, and the engaged thread is pushed out and eventually the tongue piece 20
Another second tongue piece 2
Reference numeral 1 denotes a thread take-up device for a sewing machine that projects further than the first tongue piece 20 and engages the thread that has come off the first tongue piece, and guides the engaged thread into the thread hole. 2. The thread take-up device for a sewing machine according to claim 1, wherein both tongues are inclined or curved so that the inlet 19 is tapered. 3. The thread take-up device for a sewing machine according to claim 1, wherein each tip of each tongue piece is slidably fitted into a groove or an elongated hole.