JPS5819283A - Upper yarn tension reducing apparatus of 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] The present invention relates to a needle thread force reduction device for a sewing machine.

In a lockstitch sewing machine, when forming a so-called crow stitch, where the intertwining point of the upper thread and lower thread forms on the surface of the fabric,
Since it is necessary to pull up the upper thread more strongly than when forming a normal seam where the intersecting point is located at the center 1 of the thread thickness, it is necessary to pull up the upper thread more strongly than when forming a normal seam where the upper thread tension is high. However, since the thread becomes easier to break, the types of thread that can be used are limited to those that are strong.

This St* was created by focusing on these drawbacks, and is a needle thread for sewing machines that reduces tension on the needle thread, prevents thread breakage of the needle thread, and increases the number of types of thread that can be used. To provide a strain relief device.

Hereinafter, one embodiment of this JIJI will be described based on the drawings.

In the figure, l is the needle plate of the sewing machine, and 08, which has the needle hole 2 open, is designed to swing left and right by a needle bar with a needle N fixed to the lower end. The thread catcher 5 is rotatably supported on the throat plate 1 of the sewing machine, and has a thread catcher 5 fixed to one end of the hook shaft which rotates in conjunction with the main shaft (not shown) of the sewing machine.

Reference numeral 6 denotes a bobbin case, which is held so as not to rotate within the thread ring catcher 5, and an inner hook 7 is supported so as not to rotate within the inner hook 6. A bobbin (not shown) on which the T is wound is rotatably supported.

Reference numeral 9 denotes a hook as a bobbin thread holding member fixed to the head 7A of the bobbin case 7, and is fixed to a portion of the inner hook 6 located below the hook stopper 6A, and the bobbin thread T is relayed through this hook 9. It is guided to the hook stop 6A.

Reference numeral 10 denotes a bobbin thread surplus body slidably supported on a bearing 11 fixed to the throat plate 1 so as to move across the bobbin thread path between the hook 9 and the needle hole 2 of the throat plate 1. A bobbin thread hooking portion 10AiK is formed at the end, and a step screw 12 is provided at the other end.

18 is a cord having an axis perpendicular to the hook @ 4 and fixed to the lower surface of the throat plate 1; 14 is a connecting rod rotatably supported on the shaft 18; long holes 14A and 14B are formed at both ends; be. The stepped screw 12 is slidably fitted in the former long hole 14A, and the stepped screw 12 is fitted in the latter long hole 14B so as to mesh with a gear 15 fixed to the hook shaft 4. A gear l? rotates around a fixed shaft 16 perpendicular to the hook shaft 4. A bin 18 provided eccentrically on the upper surface of the cap is fitted.

Similarly, the stroke of the bobbin thread pulling body 1o is adjusted so that the bobbin thread of one stitch length is pulled out from the bobbin teeth 7.

Further, the timing at which the bobbin thread let-out body 1o lets out the bobbin thread T is such that it is carried out while the needle thread take-up (not shown) is descending and tension is acting on the needle thread NT.

- When the upper thread take-up is rising, the lower thread T is fed out, and the tension applied to the knife and the lower thread T causes excessive tension on the upper thread, and when no tension is applied to the upper thread NT. When the bobbin thread T is let out, the tension of the bobbin thread T causes the needle thread NT to be stretched downwards of the fabric, causing the intersection point to be below the fabric, making it impossible to perform crow stitching.

Similarly, if the hook 9 is not required, the bobbin thread holding member may be a known plate spring for adjusting bobbin thread tension provided in the bobbin case.

Also, depending on the subgenus, the length of one stitch of the bobbin thread varies,
In this case, an eccentric screw portion is provided at the tip of the stepped screw 12 or the bin 18 to adjust the movement amount of the bobbin thread payout body.
This allows the stepped screw 12. Set the bin 18 eccentrically and thread the bobbin thread.
Fine adjustment of the movement am of the bobbin thread puller which can be attached to the drawer lO or the gear 17 is performed.

Next, this invention will be explained in detail.

FIG. 1 shows a state in which the balance (not shown) is in a descending state from the top dead center and the needle N is descending. In this state, tension is applied to the needle thread NT, but its value is gradually decreasing.Then, by the 170 rotations of the gear linked to the hook shaft 4, the bobbin thread pull-out body 10 moves one stitch of the bobbin thread. The bobbin thread is moved in the horizontal direction by a stroke corresponding to the length, and at this time, the bobbin thread is hooked to the bobbin thread T, and the bobbin thread of one stitch length is sewn out from the bobbin case 7.

Next, as shown in Fig. 2, as the needle N rises, the thread take-up raises the needle thread NW by σ1 and raises the bar together with the bobbin thread T. No tension is applied to the bobbin thread T, but the tension is applied to the needle thread NT. will be reduced. According to experimental values, the tension of this upper thread NT is 80.
The needle thread tension was 9, which was lower than the conventionally required needle thread tension of 180 to 200 g.

As described above, according to the present invention, the tension on the needle thread during stitch formation can be reduced by letting out an excess of the bobbin thread for the length of one stitch in advance, thereby preventing the needle thread from breaking. It is possible to form a beautiful and perfect purl seam, and even threads with low tensile strength can be used as needle threads.

[Brief explanation of the drawing]

1 and 2 are partially sectional front views of one embodiment of the present invention, and FIG. 8 is a partially sectional bottom view of the first embodiment. 5...-Thread ring catcher□ 7--Bobbin case 9...Hook 10 as a bobbin thread holding member...Name of bobbin thread pay-out body agent Patent attorney Nagoya - Male

Claims (1)

[Scope of Claims] A rotating thread ring catcher, a bobbin nurse held stationary within the thread ring catcher and rotatably housed as a bobbin wound with bobbin thread, and a bobbin case supported by a hobbin case. A bobbin thread holder that guides the bobbin thread coming out, and a bobbin thread holder that is always located outside the bobbin thread path between the bobbin thread holder and the needle plate.
A bobbin thread thinner that moves across the bobbin thread path so as to edge out the bobbin thread of one stitch length when the needle thread is under tension during its descent in synchronization with the fabrication of the needle thread take-up. - A needle thread tension reducing device for a sewing machine, comprising a body and a body.