JP3441699B2 - Vertical full rotation hook for high-speed zigzag stitching - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DP type full vertical rotary hook (vertical full rotary hook for high-speed zigzag stitch).

[0002]

2. Description of the Related Art FIG. 13 is a view showing a conventional DP type full vertical rotary hook 1. In addition, in FIG. 13, the outer hook 3 is cut and shown. The vertical full rotary hook 1 is constituted by an outer hook 3 and an inner hook 2. Outer hook 3 is the outer hook body 6
And the inner hook holding member 7, and the outer hook body 6
An inner hook holding member 7 is attached to the rail and a rail groove 8 extending in the circumferential direction around the rotation axis 5 is formed. This track groove 8
The rail 4 formed on the outer peripheral portion of the bottom wall 15 of the inner hook 2 is fitted into the inner hook 2, and the inner hook 2 is rotatably attached to the outer hook 3.

While the inner hook 2 is prevented from rotating by a hook stopper member (not shown) of the sewing machine, the outer hook 3 is rotated around the rotation axis 5 in the direction of the arrow 11 (clockwise when viewed from the right in FIG. 13). Direction) and the needle 14 moves to the outer hook 3
A seam is formed by reciprocating up and down on the base end side. By operating the respective members in this manner, it is possible to sew even forward and reverse stitches without causing hitch stitches (entangled stitches).

In order to make the space between the rail 4 and the rail groove 8 oil-free, the rail 4 and the lower wall 15 are covered with a polymer resin layer over the entire circumference.

[0005]

In the above-described vertical full rotary hook 1, the outer hook 3 rotates at a high speed around the axis 5 with the rail groove 8 and the rail 4 in sliding contact with each other during sewing. Therefore, with the rotation of the outer hook 3, the synthetic resin layer covering the rail 4 is worn. Further, the DP type vertical full rotary hook 1 is used in a state in which the outer rotary hook 3 rotates faster than the DB type vertical full rotary hook, for example, 8,000.
Rotate at a speed of 0 rpm or more. Therefore, the wear rate of the synthetic resin layer of the rail 4 is also high. When the synthetic resin layer wears in this way, a clearance is generated between the rail groove 3 and the rail 4.

As shown in FIG. 13, in the vertical full-rotation rotary hook 1, since the weights of the peripheral wall 12 and the flange portion 9 are biased to one side in the thickness direction (right side in FIG. 13), the center of gravity of the inner rotary hook 3 is It is located on one side in the thickness direction with respect to the center line 16 of the rail 4, and when the clearance is generated as described above, the inner hook 2 falls to one side in the thickness direction (right side in FIG. 13). As described above, when the outer hook 3 is rotated in a state where the inner hook 2 is tilted, the wear of the synthetic resin layer of the rail 4 is further promoted, and the life of the vertical full rotary hook 1 is shortened.

Further, as described above, since the outer hook 3 rotates at a high speed, the frictional heat generated by the sliding of the rail groove 8 and the rail 4 is large, and the damage of the synthetic resin layer is also fast.

Further, the synthetic resin layer includes the rail 4 and the bottom wall 1.
Since the entire circumference of No. 5 is covered, when the upper thread passes through the inner hook, a slight scratch formed by the passage of the thread is formed in the area between the thread dividing section and the thread pulling section of the low wall 15. There is a problem that a yarn path is generated. When a thread trail occurs like this,
There is a problem in that the upper thread is caught in the thread path when the thread passes and the upper thread is cut.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a DP type vertical full rotation rotary hook having high durability even without oil supply.

[0010]

The present invention is based on 8,000 r
An outer hook having a track groove extending in the circumferential direction is formed on the inner peripheral portion of the peripheral wall by being rotated at about pm, and a rail extending in the peripheral direction is formed on the outer peripheral portion of the bottom wall. The rail is fitted into the track groove. Having an inner hook supported on the outer hook, the needle arranged above the outer hook in a state where the inner hook is not rotated, reciprocates up and down on the proximal end side of the outer hook, When the outer hook is driven to rotate about a horizontal axis of rotation, the first bottom wall 41 of the inner hook 22 has 40 to 60% of the area of the first bottom wall 41 in the vertical full-rotation hook that forms the seam. The first plurality of first openings 46 are formed with the opening ratio, and the first peripheral wall 42 of the inner hook 22 has an area of 40 to 60 of the first peripheral wall 42.
The second plurality of second openings 47 is formed with an opening ratio of%, and the outward flange 43 of the inner hook 22 is provided with the outward flange 43.
The third plurality of third openings 4 with an opening ratio of 40 to 70% of the area of
8, the first to third openings 46 to 48 are made 20 to 40% lighter than the weight of the inner hook 22 and the inner hook 22
A bobbin case 23 is detachably attached to the bobbin case 23. The bobbin case 23 has a bobbin case body 61 for accommodating a bobbin around which a bobbin thread is wound. 20-30% of the area of the second bottom wall 64
The fourth plurality of fourth openings 66 are formed with the opening ratio of 5 and the fifth plurality of fifth openings are formed on the second peripheral wall 67 of the bobbin case body 61 with an opening ratio of 20 to 30% of the area of the second peripheral wall 67. 68, and the fourth and fifth openings 66, 68 are 10 to 30% lighter than the weight of the bobbin case body 61.
The rail 45 is formed to have a width which is about 1.5 to 2 times the thickness of the first bottom wall 41, and has a thread splitting portion 49 at one end in the circumferential direction of the rail and a thread pulling-out portion 50 at the other end. There is a vertical full rotation for high-speed zigzag stitch characterized in that only the rail except the region between is covered with a synthetic resin layer 51 made of a material having a small friction coefficient. The present invention also includes a paddle 21
Has a sword tip 28 on a flat surface 21d on the open end 21a side,
Outer hook body 2 in which a notch 39 extending in the radial direction is formed
4 and the flat surface 21 on the open end 21a side of the outer hook body 24.
It has an inner hook holding member 25 which is fixed on d and has a thread absorbing piece 34 and a lower thread guiding piece 35. The notch 39 and the inner hook holding member 25 allow the outer hook 21 and the outer hook 21 to be separated from the track groove. A communication hole 40 communicating with 29 is formed. Further, the present invention is characterized in that the synthetic resin layer is selected from the group consisting of polyetheretherketone resin, polyetherimide resin, wholly aromatic polyester resin, polyimide resin and polybenzimidazole resin. .

According to the present invention, openings are formed in the inner hook at a predetermined opening ratio. More specifically, a plurality of openings are formed in the inner bottom portion such as the first bottom wall 41, the flange 43, and the first peripheral wall 42 to the extent that the material strength of the inner top is not impaired. This reduces the weight of the inner hook. Therefore, the bias of the weight of the inner hook is reduced,
The center of gravity of the inner hook can be located on the center line side of the rail,
The fall of the inner hook inside the outer hook toward the open end is reduced. Furthermore, since the rail is formed wide in the direction parallel to the axis (thickness direction), the center of gravity of the inner hook is arranged on the center line side of the rail, which also prevents the inner hook from falling toward the open end. Get smaller. Therefore, at the time of sewing, the wear rate of the synthetic resin layer covering the rail is reduced, and the durability of the inner hook is improved. A plurality of openings are also formed in the portions of the second bottom wall 64 and the second peripheral wall 67 of the bobbin case main body 61 that accommodates the bobbin of the bobbin case 23, and the weight is reduced.

Further, since the rail is covered with the synthetic resin layer made of a material having a small friction coefficient, it is not necessary to supply oil between the rail groove and the rail. Furthermore, since the frictional force acting on the upper thread when passing over the thread is reduced, thread breakage can be prevented. In addition, since the synthetic resin layer covers the rail except for the thread-dividing portion of the rail and the area from the thread-dividing portion of the bottom wall of the inner hook to the thread pull-out portion, the thread-dividing portion and the above-mentioned area are The steel material of the inner hook is exposed. Therefore, when the thread passes through the inner hook, the upper thread does not cause a thread path in the thread dividing portion and the above-mentioned region, and the thread is prevented from being caught by the upper thread being caught in the thread path when passing through the thread. it can.

[0013]

According to the present invention, the outer hook is formed with a communication hole for communicating the rail groove with the outside of the outer hook. Therefore, when the outer hook is rotated, heat generated between the rail groove and the rail is generated. Is discharged to the outside through this communication hole, and heat is prevented from being trapped inside the outer hook. Therefore, the frictional heat slows the rate at which the synthetic resin layer is damaged, and the life of the inner hook is extended.

[0015]

1 is a front view showing a vertical full rotary hook 20 according to an embodiment of the present invention, and FIG. 2 is a side view of the vertical full rotary hook 20. As shown in FIG. Vertical rotary hook 20 is D
P-type vertical full-turn hook for high-speed zigzag stitching
It is preferably used. The vertical full rotation rotary hook 20 has an outer hook 21 that is driven to rotate about a horizontal rotation axis 27, and a rail 45 that fits into a rail groove 29 of the outer hook 21, and is rotatably held by the outer hook 21. It comprises an inner hook 22 and a bobbin case 23 which is detachably attached to the inner hook 22. The bobbin in which the lower thread is wound is accommodated in the bobbin case 23. Outer hook 21 and inner hook 22
Each of the bobbin case 23 and the bobbin case 23 is made of low carbon steel. The lower thread is omitted in FIGS. 1 and 2.

First, the sewing operation of the vertical full rotary hook 20 will be described. At the time of sewing, the inner hook 22 is fixed to a rotary shaft (not shown) extending from the machine body of the sewing machine while the inner hook 22 is prevented from rotating by a hook stopper member (not shown) of the sewing machine, and the outer hook 21 is rotated horizontally. Arrow A around axis 27
Direction (clockwise when viewed from the open end 21a side of the outer hook 21)
In addition, it is rotationally driven at a high speed of about 8,000 rpm. At the same time, the needle 83, which is inserted through the needle hole 82 of the needle plate 81 of the machine body of the sewing machine and arranged above the proximal end portion side (left side in FIG. 2) of the outer hook 21, rotates the outer hook 21. In sync with
It reciprocates in the vertical direction perpendicular to the rotation axis 27. This needle 8
The upper thread 84 brought by No. 3 is caught by the tip 28 of the outer hook 21. The captured upper thread 84 forms a loop as the outer hook 21 rotates and forms an inner hook 2
2 is displaced in the circumferential direction around 2, and is pulled up just before the lower end of this loop makes a round around the inner hook 22, and the inner hook 22 is threaded. By repeating the above operation, the lower thread (not shown) wound around the bobbin held in the bobbin case 23 and the upper thread 84 are wound around each other to form a seam.

Next, each member constituting the vertical full rotation rotary hook 20 of the present invention will be described in detail. First, the inner kettle 2
2 will be described. 3 is a front view of the inner hook 22, FIG. 4 is a rear view of the inner hook 22, and FIG.
It is sectional drawing of FIG. The shaded areas in FIG. 4 and FIG.
The portions where the synthetic resin is exposed on the surface are shown, and the other portions are the portions where the steel material is exposed on the surface. Inner kettle 2
2 is a bottom wall 41, a peripheral wall 42, and an outward flange 43.
And a stud 44 and a rail 45.
The bottom wall 41 has a perfect circular shape, and has an open end 21a on the outer peripheral portion thereof.
A semicircular peripheral wall 42 standing upright on the side (upper side in FIG. 5) is formed in a row, and further protrudes radially outward on the outer peripheral portion,
A rail 45 extending in the circumferential direction is also formed. In addition, the stud 4 that is erected on the open end 21a side is provided at the center of the bottom wall 41.
4 is formed. An outward flange 43 is formed at the end of the peripheral wall 42 on the open end 21a side so as to project outward in the radial direction and widen toward one side in the circumferential direction (arrow A direction).

The bottom wall 41 is formed with a plurality of openings (three in the present embodiment) 46 which are respectively arranged at a predetermined angle around the axis 27, and the peripheral wall 42 is provided with a predetermined space. A plurality (four in the present embodiment) of openings 47 that are opened and arranged respectively are formed, and the outward flange 43 is formed.
A plurality (two in the present embodiment) of openings 48 are formed in each. The aperture ratio of each of the openings 46 to 48 is equal to that of the bottom wall 41,
The strength of the peripheral wall 42 and the outward flange 43 is determined so as not to impair the strength of each. More specifically, the total aperture ratio of the openings 46 to 48 is selected to be 20 to 40% by weight ratio of the inner hook 22, and in the present embodiment, 30% is selected. In terms of area ratio, the opening ratio of the opening 46 is 40 to 60% of the area of the bottom wall 41, the opening ratio of the opening 47 is 40 to 60% of the area of the peripheral wall 42, and the opening ratio of the opening 48 is. , 40 to 70% of the area of the outward flange 43. That is, the inner hook without forming the opening has a weight of 12 g, but by forming the openings 46 to 48, the inner hook 22 has a weight of 8.4 g. As a result, the bias of the weight of the inner hook 22 is reduced,
The center of gravity of the inner hook 22 is set to a rail 45 rather than the inner hook of the prior art.
Can be arranged on the side of the center line 59 of the inner hook 22 so that the tilt of the inner hook 22 inside the outer hook 21 toward the open end 21a side is reduced.

As shown in FIG. 5, the rail 45 has a bottom wall 41.
A protruding portion 52 that is integrally formed by protruding radially outward (leftward in FIG. 5) from the outer peripheral portion, and a synthetic resin layer 51 that covers the protruding portion 52 and is made of a material having a small friction coefficient. To be done. This synthetic resin layer 51 is
A plurality (14 in the present embodiment) that covers the entire overhanging portion 52, penetrates the bottom wall 41 in the thickness direction, and is arranged along the outer periphery of the bottom wall 41 at a predetermined interval.
The inside of the through hole 53 is densely filled. Therefore, the synthetic resin layer 51 does not easily come off the projecting portion 52. Furthermore, this synthetic resin layer 5
No. 1 covers the overhanging portion 52 in a state where the thread dividing portion 49 which is one end portion in the circumferential direction of the rail 45 is removed. More specifically, as shown in FIG.
The region 93 between the front end 91 and the base end 92 is not covered with the synthetic resin layer 51. Therefore, this thread dividing section 49
The steel material of the inner hook 22 is exposed, and the bottom wall 41
The steel material of the inner hook 22 is also exposed in the region 58 from the yarn splitting portion 49 to the yarn pulling-out portion 50. Therefore, when the upper thread passes through the inner hook 22, the thread dividing section 49 and the bottom wall 41
A yarn path does not occur in the area 58, and when the upper thread passes through the inner hook 22, the upper thread is not caught by the yarn path and the upper thread is not cut. The reason why the synthetic resin layer 51 is not covered on the thread dividing portion 49 is that the outer hook 2
This is because the yarn splitting portion 49 hardly comes into sliding contact with the outer hook 21 during the rotating operation of 1.

Examples of the material of the synthetic resin layer 51 include polyetheretherketone resin, polyetherimide resin, wholly aromatic polyester resin, polyimide resin and polybenzimidazole resin. Each of these resins has excellent sliding properties, excellent heat resistance, and has the advantage that injection molding and extrusion molding are easy.

The rail 45 configured as described above is formed so that its thickness is wider than that of the inner hook of the prior art. More specifically, one end surface 54 of the rail 45 in the thickness direction (vertical direction in FIG. 5) is formed in the same plane as the one end surface 56 of the bottom wall 41 in the thickness direction, and the other end surface 55 of the rail 45 in the thickness direction is It projects from the other end surface 57 in the thickness direction of the bottom wall 41 to the other side in the thickness direction (upward in FIG. 5).
That is, up to the inside of the prior art, since both end faces in the thickness direction of the rail are formed substantially in the same plane as both end faces in the thickness direction of the bottom wall, the thickness of the rail is approximately 1.2 mm of the bottom wall. Equal to 1.6 mm, the inner rotary hook 2 of the present embodiment
The thickness of the second rail 45 is formed to be larger than the thickness of the bottom wall 41. That is, it is preferable that the thickness of the rail 45 is as large as possible than the thickness of the bottom wall 41 of 1.2 mm.
More specifically, the thickness of the rail 45 is selected to be about 1.5 to 2 times the thickness of the bottom wall 41 and is 2.0 mm or more and 3.
It is preferably 0 mm or less. In this embodiment, it is 2.7 mm. In this way, by increasing the thickness of the rail 45, the center of gravity of the inner hook 22 is adjusted to the rail 45.
Can be arranged on the side of the center line 59, so that the tilt of the inner hook 22 inside the outer hook 21 toward the open end 21a side is reduced.

As described above, rather than the conventional rotary hook,
Since the inner hook 22 of the present embodiment has a lighter weight and the rail 45 is formed wider, the tilt of the inner hook 22 inside the outer hook 21 can be reduced. Therefore, the area in which the synthetic resin layer 51 slides in contact with the rail groove 29 of the outer hook 21 becomes smaller, the wear rate of the synthetic resin layer 51 becomes slower than in the prior art, and the life of the inner hook 22 becomes longer.

Next, the outer hook 21 will be described. Figure 6
Is a front view of the outer hook 21 and FIG. 7 is a side view of the outer hook 21. The outer hook 21 includes an outer hook body 24 and an inner hook holding member 25. The outer hook body 24 is
It has a tapered sword tip 28 formed at one end of the outer peripheral flange portion 36, and this flange portion 36 has an outer hook body 2
4 is formed with a communication hole 38 that communicates the outside with the inside, and a notch 39 extending in the radial direction is formed in the flat surface 21d of the outer hook body 24 on the open end 21a side. The inner hook holding member 25 includes an inner hook holding body 33 fixed on the flat surface 21d on the open end 21a side of the outer hook holding body, and a thread absorbing piece integrally formed at one end of the inner hook holding body 33. 34 and the inner hook holding body 33 at the outer side of the outer hook 21 in the radial direction (upper side in FIG. 6) than the thread absorbing piece 34.
And a lower thread guide piece 35 formed integrally with one end of the lower thread guide piece 35.

The inner hook holding member 25 has a sword tip 28.
The outer hook body 2 closer to the open end 21a than the tip 28a of the
It is fixed via screws 26 on the end face 21d extending in the direction perpendicular to the rotation axis 27 of the No. 4 screw. The rail 4 of the inner hook 22 described later is provided between the outer hook body 24 and the inner hook holding member 25.
A rail groove 29 into which the number 5 is fitted is formed extending in the circumferential direction. By mounting the inner hook holding member 25 on the outer hook body 24, the communication hole 38 of the flange portion 36 can be obtained.
In addition to the above, a communication hole 40 formed by the notch 39 and the inner hook pressing member 25 is formed.
The outside of the outer hook 21 and the rail groove 29 communicate with each other via 8, 40. Therefore, when the outer hook is rotated, the rail groove 29 and the rail 4 are
The frictional heat generated between the outer ring 21 and the outer ring 5 is discharged to the outside through the communication holes 38 and 40, and the heat is not accumulated in the outer hook 21. Therefore, the frictional heat generated by the sliding of the outer hook 21 and the inner hook 22 reduces the speed at which the synthetic resin layer 51 is damaged, thereby extending the life of the inner hook 22. Further, due to the centrifugal force of the outer hook 21, scraps of the synthetic resin layer 51 generated when the inner hook 22 and the outer hook 21 slide with each other are discharged from the communication holes 38 and 40 to the outside of the outer hook 21.

Next, the bobbin case 23 will be described. 8 is a front view of the bobbin case 23, FIG. 9 is a rear view of the bobbin case 23, and FIG. 10 is a cross-sectional view of the bobbin case 23. The bobbin case 23 has a bottomed cylindrical bobbin case body 61 that opens to one side in the thickness direction (downward in FIG. 10), and a bottom wall 6 of the bobbin case body 61.
4, a slidably mounted latch 62, an operation piece 63 for operating the latch 62, and a standing piece from the bottom wall 64 toward the opening end (downward in FIG. 10) side are provided. Bite 2
The second stud 44 is inserted into the cylindrical portion 65 having a right cylindrical shape.

As shown in FIGS. 8 to 10, a plurality of bobbin case main bodies 61 are provided on the bottom wall 64 (6 in this embodiment).
A plurality of openings 66 are formed in the peripheral wall 67, and a plurality (seven in this embodiment) of openings 68 are formed in the peripheral wall 67. The opening ratio of each of the openings 66 and 68 is determined by the bottom wall 64 and the peripheral wall 67.
Is determined so as not to impair the strength of the bobbin case body 61. More specifically, the total opening ratio of the openings 66 and 68 is selected to be 10 to 30% of the weight ratio of the bobbin case body 61. In the form, 20% is selected. In terms of the area ratio, the opening ratio of the opening 66 is 20% of the area of the bottom wall 64.
The opening ratio of the opening 68 is set to 20 to 30% of the area of the peripheral wall 67. That is, the weight of the bobbin case which was 11.8 g in the state where the opening is not formed is, for example, 1 in the bobbin case 23 of the present embodiment.
It becomes as light as about 0.0g. Therefore, with the bobbin case 23 attached to the inner hook 22, the inner hook 22
Since the weight deviation between the bobbin case 23 and the bobbin case 23 becomes smaller than in the prior art, the center of gravity of the inner hook 22 is set to the center line 5 of the rail 45.
It can be placed on the 9 side, and the inner hook 2 inside the outer hook 21
The fall of 2 becomes small. Further, the portion of the bobbin case 23 that does not require strength may be made of an aluminum material instead of the low carbon steel material. That is, the operation piece 63 that does not require strength is made of aluminum. This allows the bobbin case 2
The weight of the inner hook 22 can be further reduced, and the tilting of the inner hook 22 can be further reduced.

Next, with reference to FIG. 11 and FIG. 12, the test results of the durability test of the vertical full rotation rotary hook 20 conducted by the present inventor will be described. FIG. 11 shows the rail 45 and the rail groove 2.
9 is a diagram showing a time-dependent change in the clearance in the diametrical direction with respect to FIG. 9, and FIG. 12 is a diagram showing a time-dependent change in the clearance in the thickness direction between the rail 45 and the track groove 29. Figure 11
And dashed lines L1 and L4 in FIG. 12 show changes with time in clearances of the conventional vertical full-rotation rotary hook 1 having a rail thickness of 1.6 mm without reducing the weight of the inner hook and the bobbin case. The alternate long and short dash lines L2 and L5 in FIG. 12 show changes with time in clearances of the vertical full-rotation rotary hook in which the thickness of the rail is 2.7 mm and other conditions are the same as those of the conventional vertical full-rotation rotary hook 1. 11 and the solid line L in FIG.
3, L6, the rail 45 has a thickness of 2.7 mm, and the inner hook 22 and the bobbin case 23 have openings 46 to 48, 66,
68 is formed to reduce the weight, and the outer hook 21 has a communication hole 3
The change with time of each clearance of the vertical full rotation rotary hook 20 of this embodiment which formed 8 and 40 is shown. In this durability test, the outer hook 21 was rotated for 5 seconds at a speed of 8,000 rpm and then intermittently repeated for 5 seconds.

As shown by the line L1 in FIG. 11, in the conventional vertical full rotary hook, the clearance in the diameter direction (vertical direction in FIG. 13) reaches 400 μm or more in a short time T1, and the line in FIG. As shown by L4, the clearance in the thickness direction (left and right direction in FIG. 13) also reaches 100 μm or more. Therefore, it can be seen that the synthetic resin layer on the rail has a high wear rate and poor durability. In addition, the vertical full rotary hook with the rail thickness increased to 2.7 mm is shown in Fig. 11.
As shown by the line L2, the diametrical clearance does not reach 400 μm even after the lapse of the elapsed time T2 which is more than twice the elapsed time T1 and the wear rate of the synthetic resin layer in the diametrical direction. However, as shown by the line L5 in FIG. 12, the clearance in the thickness direction reaches 170 μm or more at the elapsed time T2. On the other hand, in the vertical full rotary hook 20 of the present embodiment, as shown by the line L3 in FIG. 11, even if the elapsed time T3 that is five times or more of the elapsed time T1 has elapsed, the diametrical clearance is It does not reach 150 μm, and as shown by the line L6 in FIG. 12, the clearance in the thickness direction is 100 μm.
It has not reached m. From the above results, in the vertical full-rotation rotary hook 20 of the present invention, the wear rate of the synthetic resin layer 51 of the rail 45 in both the diametrical direction and the thickness direction is the same as the conventional vertical full-rotation rotary hook 1. It is much slower than the above, and thus the vertical full rotary hook 20 of the present invention is more durable than the vertical full rotary hook 1 of the prior art.
You can see that it has a long life.

[0029]

According to the present invention, since the opening is formed in the inner hook at a predetermined opening ratio, the weight of the inner hook is reduced. This reduces the bias in the weight of the inner hook,
The center of gravity of the inner hook can be located on the center line side of the rail,
The fall of the inner hook inside the outer hook toward the open end is reduced. Furthermore, since the rail is formed wide in the direction parallel to the axis (thickness direction), the center of gravity of the inner hook is arranged on the center line side of the rail, which also prevents the inner hook from falling toward the open end. Get smaller. Therefore, at the time of sewing, the wear rate of the synthetic resin layer covering the rail is reduced, and the durability of the inner hook is improved. In addition, the synthetic resin layer, except for the thread dividing portion and the area from the thread dividing portion of the bottom wall of the inner hook to the thread pulling portion,
Since the rails are covered, the steel material of the inner hook is exposed in the thread dividing portion and the above-mentioned area, which prevents the thread from being cut because the upper thread is caught in the thread path when the thread passes over the thread. The bobbin case body 61 is also formed with an opening at a predetermined opening ratio to further reduce the weight.

According to the present invention, the outer hook has a radially extending notch 39 formed in the flat surface 21d on the open end 21a side of the outer hook body 24 and the inner hook fixed to the flat surface 21d. Since the pressing member 25 forms the communication hole 40 that communicates the rail groove with the outside of the outer hook, the frictional heat generated between the rail groove and the rail when the outer hook is rotated is discharged to the outside. . Therefore, the synthetic resin layer is prevented from being damaged by the frictional heat, and the life of the inner hook is extended.

[Brief description of drawings]

FIG. 1 is a front view showing a vertical full rotation rotary hook 20 according to an embodiment of the present invention.

FIG. 2 is a side view of a vertical full rotary hook 20.

FIG. 3 is a front view of an inner rotary hook 22.

FIG. 4 is a rear view of the inner hook 2.

FIG. 5 is a cross-sectional view of an inner rotary hook 22.

FIG. 6 is a front view of an outer rotary hook 21.

7 is a side view of the outer hook 21. FIG.

8 is a front view of the bobbin case 23. FIG.

9 is a rear view of the bobbin case 23. FIG.

10 is a sectional view of the bobbin case 23. FIG.

FIG. 11 is a diagram showing a change with time in the clearance in the diametrical direction between the rail 45 and the rail groove 29.

FIG. 12 is a diagram showing changes over time in the clearance in the thickness direction between the rail 45 and the rail groove 29.

FIG. 13 is a view showing a DP type full-vertical rotary hook 1 according to the prior art.

[Explanation of symbols]

20 DP type vertical full rotary hook 21 Outer bite 22 Inner Kama 27 rotation axis 29 tracks 38, 40 communication holes 45 rails 46-48, 66, 68 openings 49 Thread division 51 synthetic resin layer 59 Center line

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) D05B 1/00-97/12

Claims (3)

(57) [Claims] 1. An outer hook which is rotated at about 8,000 rpm and in which a rail groove extending in the circumferential direction is formed on the inner peripheral portion of the peripheral wall, and a rail extending in the peripheral direction on the outer peripheral portion of the bottom wall are formed. A needle arranged above the outer hook with the inner hook fitted in the rail groove and supported by the outer hook, and the inner hook being stopped from rotating, is provided on the proximal end side of the outer hook. In the vertical full rotation hook that forms the seam by reciprocating up and down and the outer hook rotating and driving about the horizontal axis of rotation, the first bottom wall 41 of the inner hook 22 is provided with the first bottom wall 41 of the first bottom wall 41. The first plurality of first openings 46 are formed with an opening ratio of 40 to 60% of the area, and the first peripheral wall 42 of the inner hook 22 is provided with a second opening with an opening ratio of 40 to 60% of the area of the first peripheral wall 42. A plurality of second openings 47 are formed, and the outward flange 43 of the inner hook 22 is provided with an outward flange. With the opening ratio of 40 to 70% of the area of the lunge 43, the third plurality of third
The opening 48 is formed, and the first to third openings 46 to 48 are 20 to 40% lighter than the weight of the inner hook 22 and the bobbin case 23 is detachably attached to the inner hook 22. The case 23 has a bobbin case main body 61 that accommodates a bobbin wound with a bobbin thread, and the second bottom wall 64 of the bobbin case main body 61 has an opening of 20 to 30% of the area of the second bottom wall 64. The fourth plurality of fourth openings 66 are formed at a rate, and the fifth plurality of fifth openings 68 are formed on the second peripheral wall 67 of the bobbin case body 61 at an opening rate of 20 to 30% of the area of the second peripheral wall 67. The fourth and fifth openings 66, 68 are made 10 to 30% lighter than the weight ratio of the bobbin case body 61, and the rail 45 is 1.5 to 2 times as thick as the first bottom wall 41. The thread is formed at one end in the circumferential direction of the rail while being formed to be wide. A vertical full rotation for high-speed zigzag stitch, characterized in that only the rail except for the region between the dividing portion 49 and the thread pulling-out portion 50 at the other end is covered with a synthetic resin layer 51 made of a material having a small friction coefficient. Kama. 2. The outer shuttle hook 21 has a sword tip 28, and a notch 39 extending in the radial direction is formed in a flat surface 21d on the open end 21a side.
And an inner hook holding member 25 fixed on the flat surface 21d on the open end 21a side of the outer hook body 24 and having a thread absorbing piece 34 and a lower thread guiding piece 35, and a notch 39 and an inner hook. The vertical full-rotation rotary hook for high-speed zigzag stitching according to claim 1, characterized in that the pressing member (25) forms a communication hole (40) that allows the outside of the outer hook (21) and the rail groove (29) to communicate with each other. 3. The synthetic resin layer is selected from the group consisting of a polyetheretherketone resin, a polyetherimide resin, a wholly aromatic polyester resin, a polyimide resin and a polybenzimidazole resin. A vertical full rotary hook for high-speed zigzag stitching according to claim 1 or 2.