JPH08196765A - Thread take-up lever for sewing machine - Google Patents

Abstract

PURPOSE: To make a thread take-up lever lightweight without lowering the strength, to reduce noise and vibration and to enhance durability of a sewing machine. CONSTITUTION: A thread take-up lever 10 oscillates vertically around a horizontal shaft 12, linked with the rotation of the main shaft 14 of a sewing machine. On both sides of an arm piece 36 between a thread guide 34 at the tip end of that lever 10 and the horizontal shaft 12, a recessed part 36A is each formed with its vertical cross section structured nearly in I-shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device for sewing machines.

[0002]

2. Description of the Related Art Conventionally, a balance-like balance body having a base end portion swingably supported around a horizontal axis in association with the rotation of a main shaft of a sewing machine and a thread guide portion at a tip end thereof is provided. As a balance device for a sewing machine, one as shown in FIGS. 13, 14 and 15 can be seen. This balance body 110 has a horizontal axis 11
The upper thread 114 is oscillated vertically to tighten the upper thread 114, and the cross-sectional shape of the arm region 118 from the base end supported by the horizontal shaft 112 to the thread guide section 116 is illustrated. 14 is formed in a vertically long rectangular shape, or the arm region 12 is formed as shown in FIG.
It was formed in a substantially barrel shape in which both sides of 0 were swollen.

[0003]

However, when the conventional balance of the sewing machine moves up and down about the horizontal shaft 112, the balance of the arm region 118 from the horizontal shaft 112 to the thread guide portion 116 depends on the weight of the arm region 118. Since the oscillating inertia force was relatively large, it caused vibration of the sewing machine, increased noise, and reduced durability. Therefore, when the weight is reduced by reducing the size by reducing the thickness while keeping the cross-sectional shape as shown in FIGS. 14 and 15, the arm extending from the horizontal shaft 112 to the yarn guide portion 116 is obtained. Area 11
There was a problem that the strength of No. 8 decreased, and there was a limit to weight reduction.

The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the weight without lowering the strength, and to improve the low noise, low vibration and durability of the sewing machine. An object of the present invention is to provide a balance device for a sewing machine that can achieve the above.

[0005]

In order to achieve this object, the balance body of the sewing machine of the present invention has its base end supported so as to be swingable around a horizontal axis in association with the rotation of the main shaft of the sewing machine. ,
Further, in a balance device of a sewing machine having a substantially arm-shaped balance body having a thread guide portion at its tip, a recess is formed in at least a part of at least one side surface of the balance body.

The recesses may be formed on both side surfaces of the balance body so that the balance body has a vertical cross-sectional shape of a substantially I shape.

Further, a through hole penetrating from one side surface to the other side surface may be formed at an appropriate position in the longitudinal direction of the balance body.

[0008]

According to the sewing machine balance apparatus of the present invention having the above-described structure, when the main shaft of the sewing machine is rotated, the balance body is vertically swung with the horizontal shaft as a fulcrum in association with the rotation of the main shaft. Tighten the upper thread with the thread guide. By forming a recess in at least a part of at least one side surface of the balance body, the balance body is lightened while maintaining necessary strength, so that the balance body moves lightly, and vibration and noise of the sewing machine Can be sufficiently reduced.

Further, by forming the recesses on both side surfaces of the balance body so that the balance body has a substantially I-shaped vertical cross-section, the weight of the balance body can be sufficiently reduced. , The most reasonable and reliable strength can be maintained.

Further, by forming a through hole penetrating from one side surface to the other side surface at an appropriate position in the longitudinal direction of the balance body, the balance body can be further reduced in weight.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention is shown in FIG.
It will be described with reference to FIGS.

In FIG. 1, an arm-shaped balance body 10 is swingably attached to a sewing machine frame (not shown) with a horizontal shaft 12 as a fulcrum. The balance body 10 is integrally formed of a material such as cast iron, steel, and aluminum. A crank 16 is fixed to one end of the main shaft 14 of the sewing machine, and a crank shaft 18 is fixed to a left side surface of the crank 16 in parallel with the main shaft 14 and at a position eccentric to the main shaft 14. The needle bar 20 is supported by bearings 22 and 24 so as to be vertically slidable.
It is fixed to. The rotational movement of the main shaft 14 causes the needle bar 20 to move vertically via the crank rod 28. Further, in the balance body 10, the rotational movement of the main shaft 14 is transmitted to the sliding element 30 via the crank rod 28,
The sliding member 30 and the shaft portion 32 of the balance body 10 slide relative to each other to swing with the horizontal shaft 12 as a fulcrum.

As shown in FIGS. 2 and 3, the balance body 10 is provided with a thread guide portion 34 at the tip, and recesses 36A are formed on both side surfaces of an arm region 36 extending from the horizontal shaft 12 to the thread guide portion 34. , 36B are formed, and the vertical cross-sectional shape thereof is substantially I-shaped. As a result, the arm region 36 from the portion of the horizontal shaft 12 to the yarn guide portion 34 has necessary and sufficient mechanical strength and is sufficiently lightweight.

In the balance device configured as described above, when the sewing machine motor (not shown) is activated to rotate the main shaft 14, the movement of the crank 16 rotating integrally with the main shaft 14 causes the crank rod 28 to move. Is transmitted to the needle bar 20, and the needle bar 20 reciprocates up and down. In addition, the rotational movement of the crank 16 causes the crank rod 2 to move.
8 is transmitted to the sliding member 30 and the sliding member 30 and the shaft portion 32 of the balance body 10 slide relative to each other,
The balance body 10 swings up and down about a horizontal axis 12 as a fulcrum. In this case, since the balance body 10 is sufficiently lightened, the swing inertia force of the arm region 36 thereof can be considerably reduced as compared with the conventional one.

The shape of the arm region 36 of the balance body 10 is not limited to that of the above-described embodiment, but may be changed to another shape.

That is, for example, as shown in FIG. 4 and FIG. 5 which is an enlarged sectional view taken along the line CC of FIG. 4, a recess 40 is formed only on one side surface of the arm region 36 of the balance body 10, and the recess 40 is formed. The vertical cross-sectional shape may be substantially C-shaped. Also in this case, it is possible to reduce the weight of the balance body 10 while maintaining the necessary strength.

Further, as shown in FIG. 6 and FIG. 7 which is an enlarged sectional view taken along the line DD of FIG. 6, the arm region 36 of the balance body 10 is shown.
The recesses 50A and 50B may be formed on both side surfaces of the structure so that the vertical cross section thereof has a substantially T-shape. Also in this case, it is possible to reduce the weight of the balance body 10 while maintaining the necessary strength.

Then, as shown in FIG. 8 and FIG. 9 which is an enlarged sectional view taken along the line EE of FIG.
6 on both side surfaces of the concave portions 36A and 36B similar to those in the original embodiment.
On the other hand, the recesses 36A and 36B may be provided with an appropriate number of through holes 60 penetrating from one side surface to the other side surface. Also in this case, the weight of the balance body 10 can be further reduced while maintaining the required strength.

Further, as shown in FIG. 10, FIG. 11 which is an enlarged sectional view taken along the line FF of FIG. 10 and FIG. 12 which is an enlarged sectional view taken along the line GG of FIG. 10, the arm region 36 of the balance body 10 is shown. A plurality of recesses 70A and 70B may be formed on both side surfaces of the recess at appropriate intervals in the longitudinal direction, and a short thick portion 80 may be left between the recesses 70A and 70B. Also in this case, the weight of the balance body 10 can be reduced while further maintaining the required strength.

[0020]

As is apparent from the above description, according to the sewing machine balance apparatus of the present invention, since at least a part of at least one side surface of the balance body is provided with the recessed portion, it has a higher strength than the conventional one. The weight can be reduced without lowering. Therefore, the swinging inertial force when the balance body swings around the horizontal axis as a fulcrum is sufficiently reduced, and the noise, vibration and durability of the sewing machine can be improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a balance device according to an embodiment of the present invention.

FIG. 2 is a front view of the balance body shown in FIG.

FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 4 is a front view of a balance body according to another embodiment of the present invention.

5 is an enlarged cross-sectional view taken along the line CC of FIG.

FIG. 6 is a front view of a balance body according to another embodiment of the present invention.

7 is an enlarged cross-sectional view taken along the line DD of FIG.

FIG. 8 is a front view of a balance body according to another embodiment of the present invention.

9 is an enlarged cross-sectional view taken along the line EE of FIG.

FIG. 10 is a front view of a balance body according to another embodiment of the present invention.

11 is an enlarged cross-sectional view taken along the line FF of FIG.

12 is an enlarged cross-sectional view taken along the line GG of FIG.

FIG. 13 is a front view of a balance body of a conventional sewing machine.

14 is an enlarged cross-sectional view taken along the line BB in FIG.

FIG. 15 is a cross-sectional view of another balance body of the conventional sewing machine.

[Explanation of symbols]

 10 Balance 12 Horizontal Axis 14 Spindle 34 Thread Guide 36 Arm Area 36A Recess 36B Recess 40 Recess 50A Recess 50B Recess 60 Through Hole 70A Recess 70B Recess

Claims (3)

[Claims] 1. A sewing machine having a substantially arm-shaped balance body, a base end portion of which is swingably supported around a horizontal axis in association with rotation of a main shaft of the sewing machine, and a thread guide portion is provided at a front end portion. In a balance device, at least a part of at least one side surface of the balance body,
A balance device for a sewing machine, characterized in that a recess is formed. 2. The balance device for a sewing machine according to claim 1, wherein the recesses are formed on both side surfaces of the balance body so that the vertical cross-section of the balance body has a substantially I-shape. 3. The balance device for a sewing machine according to claim 1, wherein a through hole penetrating from one side surface to the other side surface is formed at an appropriate position in the longitudinal direction of the balance body.