JPH06165888A - Fully rotating hook of sewing machine - Google Patents

Abstract

PURPOSE:To reduce friciton of the dart tip and a needle thread for sliding through it, and to prevent thread breakage and looping, etc., cased by a high speed rotation of a rotating hook by covering the surface of a metallic rotating hook main body with a synthetic resin, and proiding a synthetic resi dart tip so as to be freely attachable and detachable. CONSTITUTION:A vertical fully rotating hook 1 contains a roating hook 4 in which a track groove 3 is formed in the inner periphery, and a bobbin case holder 6 in which a track 5 fitted into the track groove is formed on the outer peripheral surface, and in the bobbin case holder 6, a bobbin case in which a bobbin to which a bobbin thread is wound round is contained is installed so as to be freely attahcable and detachable. In this case, as for the outer hook 4, the covering surface 11 covered with a synthetic resin matieral such as teflon, etc., is formed on the metallic surface, and in the rotating hook 4, a dart tip member 18 which is made of a synthetic resin such as teflon and resin fluride, etc., and in whih the sliding surface 12a inclined to the bottom side as it goes to the upstream side in the rotational direction A of the outer hook is formed is atachd so as to be freely attachable and detachable with screws 9, 10. Also, when the dart tip member 18 is worn by using it for a long period, it can be changed to a new tip member 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full rotary hook of a sewing machine.

[0002]

2. Description of the Related Art In a full rotary hook of a sewing machine, a rail groove is formed in an outer hook, and a rail of an inner hook is fitted into the groove, and an inner hook stopper member fixed to a machine body of the sewing machine is used as an inner hook. The outer hook is rotationally driven in this state in which the inner hook is prevented from rotating by being fitted into the detent recess.

In such prior art, when the outer hook is rotated at a high speed in order to improve the sewing speed, the upper thread is rotated due to the friction between the upper thread and the tip of the outer hook which catches the upper thread. There was a problem in that it could not follow and move smoothly, thread breakage or entanglement with the outer hook, and it was not possible to rotate the outer hook at a high speed to improve the sewing speed.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned technical problems and to provide a full rotary hook of a sewing machine which is capable of rotating the outer hook at a high speed to improve the sewing speed. Is to provide.

[0005]

According to the present invention, there is provided a full rotation of a sewing machine characterized in that the surface of a metal outer hook body is covered with a synthetic resin, and a synthetic resin sword tip member is detachably provided. .

Further, the present invention is characterized in that the sword tip member is formed with a rail groove into which the rail of the inner hook fits.

[0007]

According to the present invention, since the sword tip of the outer hook is made of synthetic resin, the upper thread caught by the sword tip can be smoothly moved even when the outer hook is rotated at a high speed. The upper thread is not entangled with the outer hook and the thread is not broken, and the outer hook can be rotated at a high speed to improve the sewing speed.

Further, according to the present invention, the sword tip made of synthetic resin is detachably provided on the outer hook body, so that the sword tip of the outer hook on which the upper thread slides is worn due to long-term use of the full rotary hook. However, it can be easily replaced, and the life of the full rotary hook can be remarkably improved, and a smooth seam can be formed to form a high-quality seam.

Further, according to the present invention, since the surface of the outer hook body is covered with the synthetic resin, sliding friction between the upper thread caught by the tip of the sword and the outer hook can be reduced, and the upper thread can be smoothly moved. It can be moved. As a result, the occurrence of thread breakage can be prevented, the outer hook can be rotated at a high speed, and the sewing speed can be improved.

[0010]

1 is a plan view showing a basic structure of the present invention, and FIG. 2 is a front view of the vicinity of a sword tip 2 of a vertical full rotation rotary hook 1 shown in FIG. The vertical full-rotation rotary hook 1 includes an outer hook 4 having a rail groove 3 formed on the inner peripheral surface thereof, and an inner hook 6 having a rail 5 fitted on the outer peripheral surface thereof, the rail 5 being fitted in the inner hook 6. A bobbin case accommodating a bobbin wound with a bobbin thread (not shown) is detachably mounted. The outer hook 4 is fixed to a lower shaft 7 which is driven to rotate about a horizontal axis of rotation, and the inner hook 6 is prevented from rotating by an inner hook stopper member (not shown) fixed to the machine body of the sewing machine. The outer hook 4 is rotationally driven in the arrow A direction by the rotation of the lower shaft 7, and the sewing operation is performed in this manner.

The outer hook 4 has a sword tip 2, and a spring 8 is fixed to the outer side of the sword tip 2 in the radial direction by screws 9 and 10. The outer hook 2 has a coating surface 11 (indicated by dots) coated with a synthetic resin material such as Teflon (trade name) on the metal surface.
This covering surface 11 can be formed by so-called lining or coating. These linings or coatings can be realized by a processing method such as a laminating method, a fluidized-bed method or an electrostatic powder vapor phase method, and the coated surface 11 may be formed by another method. By forming such a covering surface 11, the needle thread T caught by the sword tip 2 at the time of the outer hook rotating, the sliding surface 1 facing the outer hook rotating direction A downstream side.
It moves in the direction of arrow D along 2 to form a needle thread loop. The needle thread loop thus formed passes over the thread while sliding along the bottom surface 13 of the inner hook 6, and is pulled up in accordance with the raising operation of the needle (not shown) to form a stitch.

During such a sewing operation, when the sword tip 2 is arranged below the inner hook 6 in FIG. 1, the upper thread T slides on the outer peripheral surface near the sword tip 2, but on the covering surface 11. Since it can move smoothly, the upper thread T
The friction between the coating surface 11 and the coating surface 11 is small, and therefore, the upper thread T does not unnecessarily have a large tension. As a result, the needle thread T can move smoothly following the rotation of the outer hook 4, the outer hook 4 can be rotated at a high speed, and the efficiency of the sewing operation can be improved.

FIG. 3 is an enlarged perspective view of the sword tip member 18 according to one embodiment of the present invention, and FIG. 4 is a sectional view taken along section line IV-IV of FIG. Although the outer hook 4 integrally formed with the sword tip 2 has been described in the above embodiment, the main body of the outer hook 4 and the sword tip member 18 are separate bodies in this embodiment. The sword tip member 18 is made of synthetic resin, for example, Teflon (trade name) or fluorinated resin. The sword tip member 18 has a sliding surface 12 inclined toward the bottom of the rotary hook as it goes to the upstream side of the rotary hook rotation direction A, similarly to the above-mentioned sword tip 2.
A is formed, and screw holes 19 and 20 into which the screws 9 and 10 are screwed are formed. Such a sword tip member 1
8 can be detachably attached to the outer hook body by using the screws 9 and 10 by using the outer hook body in which the sword tip 2 is cut at a portion indicated by a virtual line 21 in FIG. Therefore, when the sword tip member 18 is worn due to long-term use, the sword tip member 18 can be easily replaced with a newly prepared sword tip member.

As another embodiment of the present invention, as shown in FIG. 5, a sword tip 24 of a horizontal full rotary hook 23 is provided with a coating surface 25 (shown with dots) similar to the above-mentioned coating surface 11. You may do it. Such a horizontal full rotary hook 23
Also, when the outer hook 27 is driven to rotate in the direction of arrow B, the upper thread T caught by the sword tip 24 is moved by arrow 26.
It can move smoothly along the direction indicated by.
As a result, the friction between the sliding surface 25 and the upper thread T can be reduced and the thread can be smoothly passed over, so that the outer hook 27 can be rotated at a high speed and the sewing speed can be improved.

In still another embodiment of the present invention, the entire surface of the metal outer hook such as iron or steel may be covered with a synthetic resin such as Teflon (trade name) mentioned above.

[0016]

According to the present invention, since the sword tip of the outer hook is made of synthetic resin, the friction between the sword tip and the needle thread sliding on the sword tip can be reduced as much as possible. No large tension is generated unnecessarily on the yarn, and therefore, even if the outer hook is rotated at a high speed, yarn breakage or looping does not occur. Moreover, since the outer hook can be rotated at high speed, the sewing speed can be improved.

Further, according to the present invention, since the sword tip member made of synthetic resin is detachably provided on the outer hook, even if the sword tip member is worn by the contact between the sword tip member and the upper thread,
It can be easily replaced, which allows the rotary hook to be used for a long time.

Further, according to the present invention, since the surface of the outer hook body is covered with the synthetic resin, the sliding friction between the upper thread caught by the sword tip and the outer hook can be reduced, and the upper thread can be smoothly moved. It can be moved. As a result, the occurrence of thread breakage can be prevented, the outer hook can be rotated at a high speed, and the sewing speed can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a basic structure of the present invention.

FIG. 2 is a front view of the vicinity of a sword tip 2 of the vertical full rotation rotary hook 1 shown in FIG.

FIG. 3 is a perspective view of a sword tip member 18 according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along the section line IV-IV in FIG.

FIG. 5 is a horizontal full rotary rotary hook 2 according to still another embodiment of the present invention.
It is a front view which shows 3.

[Explanation of symbols]

 1 Vertical full rotation rotary hook 2,24 Blade tip 4,27 Outer rotary hook 6 Inner rotary hook 11,25 Cover surface 18 Blade tip member 23 Horizontal full rotation rotary hook

Claims (2)

[Claims] 1. A full-rotation rotary hook for a sewing machine, characterized in that the surface of a metallic outer hook body is covered with a synthetic resin, and a synthetic resin sword tip member is detachably provided. 2. The full rotary hook of the sewing machine according to claim 1, wherein the sword tip member is formed with a rail groove into which the rail of the inner hook fits.