JPH08309063A - Blade type rotary needle thread take-up - Google Patents

Abstract

PURPOSE: To easily form the needle thread loop of an appropriate size and to prevent sewing defects such as stitch skipping or the like by attaching a member for bypassing a needle thread route to an outer peripheral side from a line connecting the two needle thread holding points of a needle thread loop forming process so as to be able to adjust a position. CONSTITUTION: In this blade type rotary needle thread take-up 1 for which a thread take-up amount adjusting pin 17 is fixed so as to be able to adjust the position, when the thread take-up amount adjusting pin 17 is fixed to the position corresponding to sewing conditions in an oblong hole and a sewing machine is operated, in the forming process of the needle thread loop in the arm shaft turning angle of 120-210 deg., needle thread 7 bypasses a route passing through the thread take-up amount adjusting pin 17 on an outer side from the line connecting the needle thread holding points A and B. As a result, a needle thread take-up curve 10b, that is the needle thread supply amount of the needle thread take-up 1, is reduced from a standard and a shuttle curve 11, that is a difference with the needle thread pull-in amount of a shuttle, that is the slack amount of the needle thread 7, that is also the size of the needle thread loop, becomes optimum for the sewing conditions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade-type rotary balance for an industrial sewing machine, which is suitable for high-speed sewing and formation of soft seams, and which carries out the upper thread and tightens the seams.

[0002]

2. Description of the Related Art Conventionally, blade type rotary balances shown in FIGS. 1 to 3 have been known (as an example, the one described in Japanese Patent Publication No. 36-18036, although the rotating direction is opposite). is there). The rotary balance 1 includes a balance crank 8 eccentrically provided on an upper shaft (not shown) and a circular back plate 2
Are fixed together through. Reference numeral 9 is a cover plate at the tip of the arm of the head, and the back plate 2 is loosely fitted in the circular hole.

The upper thread 7 is fed from a thread guide 3 (not shown) on the winding side.
It extends to the seam through the balance 1, the thread guide 4, the needle bar thread hook 5, and the needle 6. When the balance 1 is rotated clockwise in this state, the needle thread 7 engaging with the balance 1 behaves as shown in FIG. In addition, the thread count of the balance becomes maximum at (3), and the supply amount of the upper thread 7 becomes maximum at (1).

The details of the behavior of the upper thread 7 are as shown in the graph of FIG. 3 by a balance curve 10 representing the upper thread supply amount of the balance and a shuttle curve 11 representing the upper thread withdrawal amount of the shuttle. According to this, the needle 6 sticks into the cloth 12 when the rotation angle of the upper shaft is 120 °, and the loop 1
3 is formed under the cloth. At this time, the thread amount difference 14a between the balance curve 10a and the shuttle curve 11 is the theoretical slack amount of the upper thread 7. Conventionally, the amount of slack 14a cannot be adjusted.

[0005]

The optimum size of the needle thread loop 13 is determined by the sewing conditions such as the type of the upper thread, the thickness and the type of cloth, the thickness, etc. Will also change. That is, the optimum upper thread slack amount 14 exists for each sewing condition of the sewing machine. Nevertheless, in the conventional blade-type rotary balance, the upper thread slack amount 14 cannot be adjusted, so that when the sewing process is changed, the thickness of the cloth is extremely changed or the type of thread is changed. Is
The size of the needle thread loop 13 may deviate from the optimum size, and the needle thread loop 13 may be caught by the tip of the sword of the outer hook of the hook, resulting in skipping.

It is an object of the present invention to provide a blade-type rotary balance which does not cause stitching defects such as skipped stitches under any use condition of the sewing machine.

[0007]

In order to achieve the above object, the blade-type rotary balance of the present invention bypasses the upper thread path to the outer peripheral side of the line connecting the two upper thread holding points in the needle thread loop forming process. The member that allows the position adjustment is attached.

[0008]

In the blade-type rotary balance constructed as described above, when the sewing machine is operated with the needle thread detouring member attached at a position according to the sewing conditions, the needle thread is fed through the needle thread loop during the needle thread loop forming process. By passing around the line connecting the two upper thread holding points through the bypass member, the upper thread supply amount of the balance is reduced from the standard, and the difference from the upper thread withdrawal amount of the shuttle, that is, the upper thread slack. The amount, and thus the size of the needle thread loop, is optimal for the sewing conditions.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the vane type rotary balance of the present invention will be described with reference to FIGS.

This balance 1 is basically the same as a conventional blade-type rotary balance, and has a circular back plate 2 on a balance crank 8 which is eccentrically provided on an upper shaft (not shown) interlocking with a main shaft. , Fixed together.

The back plate 2 is loosely fitted in the circular hole of the cover plate 9 at the tip of the arm of the head, and the rotary balance 1 rotates together with the back plate 2 by the rotation of the balance crank 8 by the rotation of the upper shaft. be able to.

As shown in FIG. 4 (1), the back plate 2 has an elongated hole 15 in the outer peripheral direction from a line connecting upper thread holding points A and B of an arm portion 1b, which will be described later, in the balance 1. Is provided in the long hole 15, and the thread take-up amount adjusting pin 1 is provided.
7 is fixed by a mounting nut 18 so that its position can be adjusted.

The balance 1 comprises an arm portion 1b extending from a base portion 1a fixed to a back plate 2 and a holding portion 1c at its tip,
Upper thread holding points A and B are present on both sides of the base end of the arm portion 1b.

The base portion 1a has an anti-circular shape, and ear portions 1a ', 1a "are formed at both ends of the chord portion.
Reference characters a ′ and 1a ″ prevent the upper thread 7 from being drawn between the base portion 1a and the back plate 2. Both are curved toward the lid plate 9 so that the ear 1a ′ has the back plate 2. It is recessed in the peripheral notch, and the ear portion 1a ″ is recessed in the hole 2a of the back plate 2.

The arm portion 1b has a width narrower than that of the chord portion of the base portion 1a, is biased outward of the back plate 2 from the base portion 1a and extends substantially in the radial direction, and has a gap between the arm portion 1b and the back plate 2. ing. The tip of the arm 1b is slightly bent toward the cover plate 9. The edges on both sides of the arm portion 1b serve as cams for feeding the upper thread 7 from the bobbin, loosening it, pulling it up from under the needle plate, and tightening stitches.

The arm portion 1b is provided with a long hole 16 at a position corresponding to the long hole 15 of the back plate 2 so that the fixing position of the thread take-up amount adjusting pin 17 can be adjusted.

The holding portion 1c extends from both sides of the arm portion 1b in an arc shape having a center substantially coinciding with the center of rotation of the balance.

In the vane type rotary balance having the above-described structure, when the thread take-up amount adjusting pin 17 is fixed at a position corresponding to the sewing condition in the elongated hole 15 and the sewing machine is operated, as shown in FIG. In the process of forming the upper thread loop 13 at the upper shaft rotation angle of 120 to 210 °, the upper thread 7 has the upper thread holding point A,
Bypassing the path passing through the thread take-up amount adjusting pin 17 outside the line connecting the upper thread holding points B, and as a result, the balance curve 10b,
That is, the upper thread supply amount of the balance is decreased from the standard, and the hook curve 1
1, that is, the difference 14b from the hook withdrawal amount of the upper thread, that is, the amount of slack of the upper thread 7, and the size of the needle thread loop is optimal for the sewing conditions.

Instead of fixing the thread take-up amount adjusting pin 17 through the long hole 15 of the back plate 2 and the long hole 16 of the thread balance 1 so that the position can be adjusted, as shown in FIG. A plurality of taps 19 outside the line connecting the holding points A and B
And then a plurality of pin relief holes 20 are provided in the back plate 2 at the positions matching the taps 19, and the thread take-up adjustment pin 1
Even if 7 is fixed to any tap 19, the same effect can be obtained. In addition, the thread take-up adjustment pin 17
Is not limited in size and shape as long as it can bypass the upper thread even if it is not thin.

[0020]

Since the present invention is configured as described above, it has the following effects.

That is, by attaching the thread take-up adjusting pin at a position according to the sewing conditions, it is possible to easily form an upper thread loop of an appropriate size and prevent stitching defects such as stitch skipping.

[Brief description of drawings]

FIG. 1 is a diagram of a conventional blade-type rotary balance,
(1) is a front view and (2) is a side view of a main part.

FIG. 2 is a diagram illustrating the behavior of the upper thread at each rotation position of the conventional blade-type rotary balance.

FIG. 3 is a diagram for explaining the behavior of the upper thread when the needle thread loop is formed in the conventional blade-type rotary balance.

FIG. 4 is a diagram relating to a blade-type rotary balance of the present invention,
(1) is a front view, (2) is a side view, and (3) is a side sectional view in the vicinity of the thread take-up amount adjusting pin.

FIG. 5 is a diagram illustrating the behavior of the upper thread when the needle thread loop is formed in the blade-type rotary balance of the present invention.

FIG. 6 is a view relating to another vane type rotary balance of the present invention, (1) is a front view, and (2) is a side view.

[Explanation of symbols]

 1 Blade type rotary balance 2 Back plate 8 Crank 9 Lid plate 13 Needle thread loop 15 Long hole 16 Long hole 17 Thread take-up amount adjusting pin (needle thread route bypass member) A Upper thread holding point B Upper thread holding point

Claims (1)

[Claims] 1. A blade-type rotary balance having a position-adjustable member on the outer peripheral side of a line connecting two upper thread holding points in the needle thread loop forming process, the member being detoured.