JP2747302B2 - Sewing machine balance device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device for a sewing machine, and in particular, reciprocates in a horizontal direction in conjunction with an upper shaft, and catches and pulls a yarn between yarn guides in a forward movement. The present invention relates to a sewing machine balance device which supplies a thread necessary for forming a stitch while releasing the thread when returning, and absorbs a thread slack.

2. Description of the Related Art As shown in FIGS. 9 to 11, in this type of a balance apparatus, a balance cover a is provided above and below a locus drawn by a thread engagement portion of the balance.
b, the thread N released from the balance c is regulated from above and below so that the loose thread does not catch on other parts of the sewing machine (Japanese Utility Model Application No. 60-174622). In order to prevent the thread from clinging to the balance, a thread wiper or a thread holder consisting of a brush, sponge, cloth and leather skirt is provided,
Thread wiping as the balance is pulled in from here, or holding the released thread (Japanese Patent Application No. 60-1808)
No. 70).

Problems to be Solved by the Invention The above-described thread holder and thread wiper can provide a certain effect in preventing loose threads from being stuck to the balance, but the problem is that the balance reciprocates. Accompanying this is a slapping sound such as fluttering or shuffling, which is unpleasant. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and to prevent a thread from sticking to a balance without generating a rubbing noise.

Means for Solving the Problems The present invention therefore reciprocates in a horizontal direction within a balance cover arranged vertically and interlocks with an upper shaft, and captures yarn between yarn guides arranged vertically during forward movement. In a sewing machine balance device that pulls a thread pulled in a backward movement to supply a thread necessary for forming a seam and absorbs a thread in a backward movement, a balance is provided at a thread engaging portion in a forward movement. The trajectory is located ahead of the trajectory of the thread engaging portion at the time of the backward movement, the balance cover is disposed between the thread guides, and the leading edge of the trajectory is located ahead of the trajectory within the trajectory of the balance when the balance is moving forward. The thread loop released when the balance reaches the forward end and moves backward is engaged with this projection, and the right side of the projection is It is formed so as to bend so that the thread loop is easy to slip through.

Operation The operation of the balance according to the present invention will be described with reference to FIGS.

When the balance 1 captures the yarn 3 between the yarn guides 2 and pulls it to the right to pull it in a V-shape, the yarn engages with the front edge of the balance cover 4 and rides on the balance cover, and slides on the front edge. While being pulled.
FIG. 3 shows a state in which the thread 3 rides on the balance cover 4, engages with the curved portion 4b, and is expanded. When the balance 1 reaches the forward end and moves back to release the drawn thread, the thread loop engages the curved portion 4b (FIGS. 4 and 5). Then, as the loop formed by the needle is caught by the blade point of the shuttle and dragged, the loop rides on the balance cover 4 and slides off the curved portion 4b while being hooked on the curved portion 4b. As shown in FIG. 7, the thread engaging portion 1a of the balance 1 moves back inside the balance cover, so that even if the thread loop is loosened outside the balance cover 4, it does not cling to the balance 1 in the balance cover.

In order for the yarn captured by the balance to ride on the balance cover, it is desirable that the trajectory of the yarn engaging portion 1a at the time of forward movement be outside the front edge of the balance cover as shown in FIG. If the part 1a draws a trajectory as shown in FIG. 8 during the forward movement, if a part of the leading edge of the balance cover is over the trajectory, the thread may come out of the balance cover during pulling even if it once enters the balance cover. You will be able to ride.

The timing at which the loop of the thread 3 released from the balance 1 is engaged with the curved portion 4b is about the time when the needle pierces the cloth and the thread begins to loosen, that is, the balance has temporarily moved back from the reciprocating end as shown in FIG. Time is desirable. When the curved portion 4b is located to the right of that shown in FIG. 7 and the timing at which the loop of the yarn engages with the curved portion 4b is advanced, the yarn is engaged with the curved portion before the yarn is loosened. When the thread is bent to increase the tension of the thread, and the curved portion 4b is located on the left side of the figure, and the timing at which the thread loop engages with the curved portion 4b is delayed, the thread becomes too loose and comes off the balance cover. , It may hang down.

Embodiment The balance 1 has a hook-shaped thread engaging portion 1a at the tip, and is reciprocated horizontally via a link mechanism 6 by an upper shaft (not shown). The locus of the thread engaging portion 1a is the seventh. As shown in the figure, the difference between the reciprocating motion and the returning motion is different.

The left and right ends are screwed and attached to the boss 7 of the machine frame, and the balance cover 4 surrounding the trajectory of the balance 1 from above and below is bent and formed in a U-shaped cross section, and the entire surface is released by cutting.
A protrusion 4a is formed at each front edge of the upper wall and the lower wall, and the protrusion 4a
The left and right sides are smoothly curved.

The thread engaging portion 1a at the tip of the balance protrudes from the front edge of the balance cover 4 and reciprocates to draw a locus as shown in the drawing.
4a protrudes from the trajectory at the time of the backward movement, protrudes from the thread 3 that is pulled when the balance 1 reaches the forward movement end (see FIG. 2), and is inside the trajectory at the time of the forward movement. It is formed so as not to protrude more. And one side 4b
Is formed so as to engage with the thread loop when the thread released from the balance starts to loosen when the balance returns. 8 is a rising part bent at the rear part on the other side of the balance cover
Thread tension device mounted horizontally on 4c. Thread guide 2 screwed to one boss 7 together with balance cover 4
As in the case of the balance cover 4, it is formed in a U-shape and fitted to the balance cover 4 from the other side of the protrusion 4 a, and has an introduction groove 12 reaching the thread hole 11 on the front surface.

The yarn 3 unwound from a bobbin (not shown) is passed through a tension plate 13 of a thread tensioner 8, is hooked on a thread take-up spring 14, is passed through a thread hole 11 from an introduction groove 12, and then is passed through a needle 15. It has become so.

This device is configured as described above, and when the balance 1 captures the yarn 3 passed through the yarn guide 2 during the forward movement and pulls it to reach the forward movement end (FIGS. 1 and 2), The thread 3 rides on the balance cover, engages the curved portion 4b on one side of the protrusion, and the loop is expanded (see FIG. 3).

When the balance 1 reaches the forward end and moves backward, the thread loop is released from the thread engaging portion 1a of the balance, but as the needle 15 moves down, the thread loop is tensed to follow the balance that temporarily moves backward. Shrink while maintaining state. Then, at the time when the needle pierces the cloth and the thread loop starts to loosen, the thread loop engages with the curved portion 4b (FIGS. 4 and 5). When the needle 15 reaches the lowest point and rises, and the blade point catches and turns the needle thread loop, the thread loop
Is slipped and absorbed.

Effects of the Invention The present invention is configured as described above and has the following effects.

According to the apparatus of claim 1, the loop of the thread released from the balance contracts while being supported on the balance cover, so that the loose thread does not hang down and the balance moves back in the balance cover. It is no longer tied up, and like the conventional device that prevented tying of the thread to the balance,
No rubbing noise is generated with the reciprocation of the balance.

According to the engaging portion of the second aspect, the thread is not excessively tensioned, and the thread is not loosened and detached from the balance cover, and does not hang down.

[Brief description of the drawings]

FIG. 1 is a perspective view of a balance device according to the present invention, showing a state where the balance has reached a forward end. FIG. 2 is a plan view of the same, and FIG. 3 is a front view of the same. FIG. 4 is a perspective view when the balance returns.
FIG. 5 is a plan view of the same, and FIG. 6 is a front view of the same. FIG. 7 is a cross-sectional view showing the locus of the thread engaging portion at the tip of the balance. FIG. 8 is a plan view of a main part of the balance drawing another trajectory, FIGS. 8, 9 and 10 are schematic diagrams of a conventional balance device, and FIG. 9 is a diagram when the balance reaches the forward end. FIG. 11 shows a time when the balance returns, and FIG. 11 shows a locus of a thread engaging portion of the conventional balance device. DESCRIPTION OF SYMBOLS 1 ... balance, 2 ... thread guide, 3 ... thread, 4 ... balance cover 4a ... projecting part, 4b ... curved part, 8 ... thread tension device 15 ... needle

Claims (2)

(57) [Claims] 1. A reciprocating reciprocating device in a horizontal direction interlocking with an upper shaft in a vertically arranged balance cover, catching the yarn between the yarn guides arranged vertically at the time of forward movement and forming it into a V-shape. In a sewing machine balance device that releases the pulled thread at the time of backward movement and supplies the thread necessary for forming the stitch and absorbs the thread, the balance of the thread hooking part at the time of forward movement moves backward. The balance cover is disposed between the thread guides, and a protrusion projecting forward from the trajectory at the front edge of the trajectory of the balance at the forward movement thereof. When the balance reaches the forward end and moves backward, the thread loop released is engaged with the projection, and the right side of the projection is curved, and the thread is bent. The balance device is formed so that the loop can easily slip through. 2. The balance apparatus according to claim 1, wherein the portion where the thread loop released from the balance engages is formed so as to engage with the thread loop when the loop starts to loosen.