JPH0630711B2 - Full turn bite - Google Patents

Description

TECHNICAL FIELD The present invention relates to a full rotary hook provided in a lockstitch sewing machine and the like.

2. Description of the Related Art Conventionally, a lockstitch sewing machine is provided with a lower shaft that is driven to rotate about a horizontal rotation axis. An outer hook is fixed to the lower shaft. A rail groove into which a rail of the inner hook is fitted is formed on the inner peripheral surface of the outer hook, and the rail groove is formed by an outer hook body and an inner hook holding member fixed to the outer hook body. . With the rail of the inner hook fitted in such a rail groove, the inner hook holding member prevents the inner hook from coming out of the outer hook. Due to the rotation of the lower shaft, the outer hook is driven to rotate about a common axis of rotation, and at this time, the inner hook is fixed to the machine body of the sewing machine to prevent the outer hook from rotating in the rotating direction of the outer hook. ing.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In such a prior art, since the inner hook holding member made of a metal material such as iron or stainless steel directly contacts the rail of the inner hook, when the outer hook rotates, A relatively large frictional force is generated between the rail and the inner hook holding member, which causes a problem that the outer hook cannot rotate at a high speed. Moreover, when the frictional force between the rail and the inner hook holding member is large, a large hook noise is generated when the outer hook is rotated, which is not preferable in use.

Therefore, an object of the present invention is to reduce the frictional force between the rail of the inner hook and the inner hook presser so that the outer hook can be rotationally driven smoothly and at high speed without producing a large noise of the hook. It is to provide a full rotary hook.

Means for Solving the Problems The present invention relates to an outer hook main body 2 in a full rotary hook in which an outer hook is rotationally driven around its rotation axis in a state where an inner hook rail is fitted in a groove of an outer hook. Is a side surface 41 that faces the open end side and is perpendicular to the rotation axis l of the outer hook, and a bottom surface 42 that is parallel to the rotation axis l.
Is formed, and is fixed to the outer hook body 2 by screws 7 to form a rail groove for guiding the rail 4. The inner surface 8 of the outer hook holding member 6 facing the side surface 41 in parallel has a rectangular Teflon. Film forming 22
Are provided with a first interval L1 in the circumferential direction, and the coating 22 has a width d less than the radial depth d2 of the track groove.
3 and has a second distance d4 from the bottom surface 42 and a third distance d5 from the inner peripheral surface 43 of the inner hook holding member 6.

Effect According to the present invention, since the Teflon coating having a small frictional resistance is formed on the inner hook holding member, the rail of the inner hook fits into the rail groove formed by the outer hook body and the inner hook holding member. Even if the outer hook is driven to rotate in a closed state, the coating contacts the rail without directly contacting the inner hook pressing member, so that the frictional force generated between the rail and the inner hook pressing member is reduced. As a result, the outer hook can be smoothly rotated.

First Embodiment FIG. 1 is an enlarged sectional view showing a structure which is a premise of the present invention. In the full rotary hook 1 provided in a lockstitch sewing machine or the like, the outer hook body 2 holds the rail 4 of the inner hook 3 in the rail groove 5, and the inner hook holding member 6 is attached to the outer hook body 2 by using the screw 7. Fixed. The inner hook holding member 6 is formed in a generally inverted L shape, and has an inner surface 8 facing the rail 4.
A synthetic resin film 9 made of, for example, Teflon (trade name) and having a relatively small frictional resistance is formed thereon.

FIG. 2 is a perspective view of the full rotary hook 1 and FIG. 3 is a sectional view of the full rotary hook 1. The full rotary hook 1 is a vertical full rotary hook driven to rotate about a horizontal rotation axis l, and a lower shaft 10 having an axis common to the axis l is an arrow 1.
It is driven to rotate in one direction. The outer hook 12 is constituted by the outer hook main body 2 and the inner hook holding member 6, and the screw 13
Is fixed to the lower shaft 10 by means of. Therefore, the outer hook 12 is rotationally driven in the direction of arrow 11 by the rotation of the lower shaft 10. Further, the outer hook 12 has a sword tip 14, and an upper thread loop which catches an upper thread brought by a needle 15 which is reciprocally moved up and down in synchronization with a rotation operation of the lower shaft 10 by the sword tip 14. And the bobbin 17 holds the bobbin 17 held in the inner hook 3 by the bobbin case 16 to form a seam. When the inner rotary hook 3 is rotated in this manner, the protrusion of the inner rotary hook stopping member 28 fixed to the sewing machine is fitted in the inner rotary hook stopping recess 19 formed in the inner rotary hook. The rotation of the inner hook 3 in the outer hook rotation direction 11 is prevented.

In the full rotary hook 1 configured as above, the outer hook 1
Even when 2 is rotationally driven in the direction of arrow 11, since the coating 9 slides on the outer hook opening end side of the rail 4, that is, on the end surface 20 on the right side in FIG. 3, the coating 9 is fitted into the rail groove 5. The frictional force acting on the rail 4 can be reduced, whereby the outer hook 12 can be smoothly driven to rotate without generating a large noise. Moreover, even if the coating 9 is worn, the screw 7
It is possible to easily replace the inner hook holding member 6 by removing.

FIG. 4 is an enlarged cross-sectional view showing another precondition of the present invention. In the above-mentioned configuration, the coating film 9 is held by the inner hook holding member 6
Although it is formed over the entire inner surface 8 in the radial direction, the coating 9 is formed in the radial direction in the width d to the bottom of the track groove 5.
1 may be formed so as to extend in the circumferential direction. As a result, the coating film 9 can be reduced by d1-d2 as compared with the structure shown in FIGS. 1 to 3, and the inner hook pressing member 6 projects toward the outer hook opening end side by the thickness t of the coating film 9. The amount can be reduced. Further, as another precondition of the present invention, the coating film 9 may be formed over the width d3 in the radial direction as shown in FIG. As a result, the coating 9 can be reduced by the width d2-d3 as compared with the embodiment shown in FIG. 4, whereby the contact area in contact with the rail 4 is reduced and the frictional resistance is reduced. You can

One embodiment of the present invention is shown in FIG. 6 and this embodiment is similar to FIG. The Teflon-made coating 22 having a width d3 in the radial direction and a length L is spaced by a distance L1 in the circumferential direction.
And a plurality of them are formed. These coatings 22 are provided on the inner surface 8 of the inner hook holding member 6 and have a rectangular shape. Coating 22
Has the aforementioned width d3 which is less than the radial depth d2 of the track groove, and is spaced from the bottom surface 42 by a distance d4 and from the inner peripheral surface 43 of the inner hook holding member 6 by a distance d5. . Other configurations are similar to the above-mentioned configurations. That is, the outer hook body 2 is formed with the side surface 41 (see also FIG. 5) perpendicular to the rotation axis l of the outer hook facing the open end side and the bottom surface 42 parallel to the rotation axis l as described above. It As described above, the coating 22 is provided on the inner surface 8 of the inner hook holding member 6 which is fixed to the outer hook body 2 by the screw 7 and which forms a rail groove for guiding the rail 4. . As a result, a gap can be formed between the end face 20 on the open end side of the rail 4 and the inner face 8 of the inner hook holding member 6, and air can pass through this gap as indicated by arrow 23. And the cooling effect of the rail 4 can be obtained.

EFFECTS OF THE INVENTION According to the present invention, since the synthetic resin coating film having a small frictional resistance is formed on the inner hook holding member, it is possible to reduce the frictional force with the rail generated when the outer hook is rotated,
As a result, the outer hook can be rotated smoothly and at a high speed, and a large bite noise is not generated.
Moreover, since the friction between the rails and the rail grooves is reduced, it is not necessary to supply lubricating oil or the like between the rails and the rail grooves, and therefore, the mechanism for supplying the lubricating oil is not necessary, and the structure Can be significantly simplified.

Particularly, in the present invention, the inner hook holding member 6 is fixed to the outer hook main body 2 by the screw 7, which allows the outer hook to be housed and held in the inner hook. The inner hook pressing member 6 attached to the outer hook body 2 as described above easily generates noise. Therefore, in the present invention, a plurality of coatings 22 are provided on the inner hook pressing member 6 to reduce the noise as described above. In addition to the above, it is possible to allow air to pass therethrough with the first distance L1, the second distance d4, and the third distance d5, and thereby a cooling effect can be obtained. A rise in temperature can be suppressed.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view showing a structure on which the present invention is premised, FIG. 2 is a perspective view of a full-rotation rotary hook 1, FIG. FIG. 5 is a partial enlarged cross-sectional view showing another precondition of the present invention, FIG. 5 is a partial enlarged cross-sectional view showing a further precondition of the present invention, and FIG. 6 is an embodiment of the present invention. It is a partially expanded sectional view. DESCRIPTION OF SYMBOLS 1 ... Full rotary hook, 2 ... Outer hook main body, 3 ... Inner hook, 4 ... Rail, 5 ... Rail groove, 6 ... Inner hook holding member, 9, 22 ... Coating,
12 ... Outer bite

Claims (1)

[Claims] 1. A full-rotation rotary hook in which an outer hook is rotationally driven around its rotation axis in a state where an inner hook rail is fitted in a rail groove of the outer hook, and the outer hook main body 2 has its open end side. A side surface 41 of the outer rotary hook facing the rotation axis l and a bottom surface 42 parallel to the rotation axis l.
Is formed, and is fixed to the outer hook body 2 by screws 7 to form a rail groove for guiding the rail 4. The inner surface 8 of the outer hook holding member 6 facing the side surface 41 in parallel has a rectangular Teflon. A plurality of (registered trademark) coatings 22 are formed at a first interval L1 in the circumferential direction,
The coating 22 is provided with a width d less than the radial depth d2 of the track groove.
3, a full rotation rotary hook having a second distance d4 from the bottom surface 42 and a third distance d5 from the inner peripheral surface 43 of the inner hook holding member 6.