JPH038233Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a hook for a sewing machine that prevents thread from getting caught when a needle thread loop passes through the hook.

[Prior Art] FIGS. 3 to 6 are diagrams showing a horizontal hook used in a two-needle sewing machine or the like.

In the figure, 1 is the hook shaft 2 supported perpendicularly to the machine frame.
This is an outer hook fixedly attached to the outer hook, and a tip 3 for catching the needle thread is formed on the outer peripheral wall of the outer hook. Reference numeral 4 denotes an arcuate groove formed in the inner peripheral wall of the outer hook 1.

5 is an arcuate race portion 6 that fits into the annular groove 4;
A cylindrical inner hook with a bottom is formed on the outer peripheral wall of the inner hook. A hooking portion 6a ₁ is formed which is divided into a top surface and a bottom surface. Note that 61 indicates a notch portion formed between the tip end 6b and the rear end 6a of the race portion 6. A bobbin case 7 is removably fitted into the inner hook 5, and a bobbin thread bobbin (not shown) is housed inside the bobbin case.

Next, the operation of the sewing machine hook having the above structure will be explained based on the bottom part shown in FIGS. 6a to 6b.

As shown in FIG. 6a, the needle thread loop I formed in the vicinity of the outer hook 1 is moved to the tip 3 by the rotation of the outer hook 1.
_6a1 of the lace part 6, as shown in FIG. 6b. As a result, the needle thread loop I is divided into upper and lower parts of the inner hook 5, passes through the inner hook 5, becomes entangled with the bobbin thread (not shown),
A seam is formed.

[Problems to be solved by the invention] By the way, the part of the needle thread loop I that is divided downward at the hooking part _6a1 of the lace part (hereinafter referred to as
When passing through the inner hook (this portion is referred to as a seam side loop), it moves while slidingly contacting the peripheral wall and bottom surface of the inner hook 5. However, since the peripheral wall and bottom surface of the inner pot 5 have a smooth surface finish, and the corners 7 are formed in an arc shape as shown in _FIG . Frictional resistance is extremely small.

Therefore, when the outer hook 1 exceeds the position where the needle thread loop I is pulled out to the maximum (see Fig. 6 c), the stitch side loop I ₁ moves through the notch space 61 at high speed as the thread take-up is pulled up. Move in the direction of pulling out from 7. As a result, the seam side loop I
₁ gets caught (see FIG. 6(d)), and the tension generated by the subsequent lifting of the balance causes the seam-side loop I ₁ to bite between the seam-side loop I ₁ and the groove 4. , problems such as thread breakage occurred due to sliding contact with the fitting portion A.

This invention was made with attention to the above-mentioned problems, and the purpose is to provide a hook for a sewing machine that allows the needle thread loop to be smoothly removed from the hook without causing thread jamming or thread breakage. .

[Means for Solving the Problem] This invention provides a hook for a sewing machine in which a groove in an outer hook and a lace portion in an inner hook fit together, and the tip and rear end of the lace portion in the inner hook are fitted together. The inner pot circumferential surface corresponding to the notch formed between the inner pot and the inner pot is a high friction surface.

[Function] In this device, the needle thread loop moves while slidingly contacting the outer surface of the inner hook, but at this time, the high friction surface formed between the tip and rear end of the lace part prevents the thread from moving. In order to provide resistance and slow down the movement speed, the needle thread loop reaches the detachment position from the hook after the groove of the outer hook and the tip of the lace portion of the inner hook separate, so that the needle thread loop smoothly leaves the hook. do.

[Example of the invention] Hereinafter, an example of this invention is shown in Figures 1 to 6.
This will be explained based on the diagram. Note that the same or equivalent parts as in the conventional example are given the same reference numerals, and detailed explanation thereof will be omitted.

In the inner pot 5 in this embodiment, a slope 8 is formed in the corner 5a where the bottom surface 8a and the peripheral surface intersect in the range from the tip 6b of the race portion 6 to the rear end 6a. Due to the high friction surface formed by the intersection portions 81 and 82 where the slope 8, the bottom surface portion 51, and the peripheral wall portion 52 intersect, a high friction force is generated in the seam side loop _I1 of the needle thread loop I that slides on this surface. It's becoming like that. Note that the other configurations are the same as those of the conventional example.

In the sewing machine hook configured as above,
As the outer hook 1 rotates, the needle thread loop I is formed at the tip of the hook.
, and move the needle thread loop I.
When the outer hook 1 passes the maximum pull-out position of the needle thread loop I, the needle thread loop I moves in the direction of being pulled out from the inner hook 5 as the thread take-up is pulled up. During this movement, a frictional force is generated between the stitch-side loop I ₁ of the needle thread loop I and the inner hook 5, but this frictional force is stronger at the intersection portions 81 and 82 than in the conventional case.
This value becomes quite large due to the sliding contact with the Therefore, the moving speed of the stitch-side loop I ₁ is lower than before, and the timing at which the needle thread loop I comes off from the inner hook 5 is delayed. As a result, when the needle thread loop I separates from the hook, the outer hook 1 has already rotated to the position where the groove 4 of the outer hook 1 and the tip 6b of the lace portion 6 are separated. It smoothly leaves the pot without getting caught anywhere.

In the above embodiment, the slope 8 is formed on the corner 5a of the inner pot 5, and the corner 8 formed thereby
1 and 82 to become a high friction surface that increases the frictional force with the needle thread loop I, but as a high friction surface that increases the frictional force with the needle thread loop I,
In particular, it is not limited to the slope 8, but other high friction surfaces can also be applied.

For example, a wave-like stepped portion may be formed at the location where the slope 8 is formed to provide a high-friction surface, or a high-friction material such as rubber may be attached to create a high-friction surface similar to the above embodiment. You can expect good results.

[Effects of the invention] As explained above, this invention has the effect that the needle thread loop can be smoothly removed from the hook without thread biting, thread breakage, etc.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of this invention, FIGS. 2 a and b are bottom views showing the operating state of the device shown in FIG. 1, and FIG. 3 is a front view showing the hook of a conventional sewing machine. Figure 4 is a plan view of what is shown in Figure 3;
Figure 5 is a perspective view of the inner pot shown in Figure 3, Figure 6a
-d are bottom views showing the operating state of the device shown in FIG. 3; 1... Outer pot, 3... Sword tip, 4... Groove, 5... Inner pot, 6... Lace part, 6a... Rear end of lace part, 6b... Tip of lace part, 61... Notch portion of the race portion, 8... slope, 81, 82... intersecting corner portion.

Claims (1)

[Claims for Utility Model Registration] (1) Having a tip on the outer periphery that supplements the needle thread loop,
It consists of an outer hook having an arc-shaped groove formed on the inner circumferential wall, and an inner hook having an arc-shaped lace portion on the outer periphery that movably fits into the groove, and the needle tip loop supplemented by the tip of the hook is attached to the hook. In a hook of a sewing machine, the hook is held in a notch formed between a leading end and a rear end of the lace portion and slides around the inner hook, wherein the notch of the lace portion of the inner hook is held in place. A sewing machine hook characterized in that the inner hook circumferential surface corresponding to the above is formed into a high friction surface. (2) The sewing machine hook according to claim 1, wherein the high friction surface is an inclined surface having an intersecting corner formed on the circumferential surface of the inner hook. (3) The sewing machine hook according to claim 1 or 2, wherein the high friction surface is comprised of a wavy stepped portion formed on the circumferential surface of the inner hook. (4) The sewing machine hook according to claim 1, wherein the high friction surface is a high friction material such as rubber attached to the circumferential surface of the inner hook.