JPH0630712B2 - Full rotary hook of sewing machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-rotary rotary hook provided in a lockstitch sewing machine, a zigzag sewing machine, or the like.

2. Description of the Related Art FIG. 10 shows an inner hook 1 provided in a conventional vertical full rotary hook.
FIG. 11 is a perspective view of the inner hook 1 thereof, and FIG. 12 is a perspective view of the inner hook 1 as seen from the rear side. For example, the inner hook 1 provided in the vertical full-turn hook
Is a cylindrical portion 2 having a substantially cylindrical shape, and a flange 3 which is continuous with one axial end portion of the cylindrical portion 2 and which expands radially outward.
It has a bottom portion 4 connected to the other end portion in the axial direction of the tubular portion 2. A rail 5 is formed on the outer peripheral surface of the cylindrical portion 2 so as to be fitted in a rail groove of an outer rotary hook (not shown), and the bottom portion 4 is provided on the open end side of the inner rotary hook 1, that is, on the front side with respect to the paper surface of FIG. A projecting stud 6 is erected, and further, a flange 3 is formed with a detent recess 7 into which a projection of an inner hook detent member (not shown) fixed to the machine body of the sewing machine is fitted. The bottom 4
Has a bridge 8 extending in the diameter direction of the inner hook 1 and having a width W1 of about 8 mm, and a pair of openings 9 and 10 formed on both sides sandwiching the bridge 8. These openings 9,
By forming 10, the weight of the inner hook 1 can be reduced, and the outside of the virtual plane P including the movement path of the needle 11 and the axis l of the inner hook 1 shown by the imaginary line in FIG. The opening 9 formed on the downstream side of the rotary hook direction A allows the needle thread caught by the tip of the outer hook (not shown) to smoothly pass through the outer peripheral surface of the inner rotary hook 1 while forming a needle thread loop. Have a big impact.

FIG. 13 is a plan view of the inner hook 1 and FIG. 14 is a bottom view of the inner hook 1. As described above, the needle thread T captured by the tip of the outer hook is along the bottom surface 12 of the bottom portion 4 in the direction indicated by the arrow m, at points C1, C2, C3, C.
4 and C5 are moved in this order. Each of these points C1
C3 and C4 among C4 to C4 are angle θ (C3) = 40 degrees, θ (C4) = 1 from the virtual plane P in FIG.
It is set around 50 degrees, and each of these points C3, C
In No. 4, the needle 11 and the thread T tend to be stagnant, and there is a problem that a thread ball or looping is likely to occur particularly when the thread has poor slipperiness.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a full rotary hook of a sewing machine capable of smoothly passing a needle thread loop and preventing the occurrence of thread balls and looping. Is.

Means for Solving the Problems The present invention is directed to a bottom portion where an inner hook stud 45 is erected,
An arcuate opening 41 that smoothly extends to the bottom flange 47 of the bobbin housed in the inner hook is formed around the stud 45, and the starting end P1a of this opening 41 is the axis l of the inner hook and the needle. The first angle θ (P1a) is formed at about 10 to 15 degrees on the upstream side in the outer hook rotation direction with respect to the virtual plane including the movement path, and the end P2a of the opening 41 is in the outer hook rotation direction from the virtual plane. A second angle θ (P2a) is formed on the downstream side at about 195 degrees, and the end surface 4 facing outward through the opening 41 of the flange 47.
8 is substantially in the same plane as the plane perpendicular to the axis l including the end surface 44 of the opening 41, and the bottom end surface 42 is the axis l by the thickness d1 of the bottom.
There is even a full rotation of the sewing machine, which is characterized by protruding outwards.

Effect According to the present invention, since the stepped surface that smoothly extends to the flange near the bottom of the bobbin housed in the inner hook is formed at the bottom of the inner hook, the flange near the bottom of the bobbin is formed from the stepped surface. Does not project, and the needle thread loop passing over the thread along the bottom of the rotary hook can be smoothly passed over without catching on the flange of the bobbin near the bottom. Moreover, since the starting end of the step surface is formed on the upstream side in the outer hook rotating direction with respect to the virtual plane including the inner hook shaft line and the needle movement path, the needle thread loop exceeds the lowermost end position of the inner hook. After that, the diameter of the needle thread passes through the start end of the step while reducing the diameter, and the tension of the needle thread in such a reduced diameter state is smaller than that in the case of expanding the diameter, and thus even if there is a step, the needle The thread can easily get over the step, and the needle thread can be moved smoothly to allow the thread to pass through the thread more easily.

Further, according to the invention, since the terminal end of the step surface is formed on the downstream side in the outer hook rotational direction with respect to the virtual plane, the needle thread loop is reduced in diameter after passing the lowermost end position of the inner hook. Since the needle thread passes through the end of the step surface, the tension of the needle thread in such a reduced diameter state is smaller than that in the case of expanding the diameter, and therefore even if there is a step, the needle thread can easily make the step. It is possible to get over it, and the needle thread can be moved smoothly. As a result, the needle thread can be passed over the thread more easily.

Further, according to the invention, the start end of the step surface formed on the inner hook bottom is formed on the upstream side in the outer hook rotational direction with respect to the virtual plane including the axis of the inner hook and the thread path of the needle, and Since the terminal end is formed on the outer hook downstream side of the virtual plane, as described above, only one of the starting end and the terminal end is formed on the outer hook rotational direction upstream side or the outer hook rotational direction downstream side with respect to the virtual plane. In comparison with the above, the needle thread can be threaded more easily and smoothly.

Particularly according to the present invention, the end surface 48 of the flange 47 is substantially in the same plane as the end surface 44 of the opening 41, and the end surface 42 of the bottom portion is the end surface 48 of the opening 41 by the thickness d1 of the bottom portion.
Since it protrudes outward from the needle thread, this also allows the needle thread to smoothly pass through.

Example FIG. 1 is a front view of an inner rotary hook 20 showing a structure which is a premise of the present invention, and FIG. 2 is a plan view of the inner rotary hook 20.
FIG. 3 shows a vertical full rotary hook 2 in which the rotary hook 20 is housed.
1 is a cross-sectional view of FIG. 1, and FIG. 4 is an overall perspective view of the vertical full rotation rotary hook 21 shown in FIG. First, Figs. 3 and 4
Referring to the drawings, a vertical full rotary hook 21 of the present embodiment includes a lower shaft 22 and a lower shaft 2 which are driven to rotate about a horizontal axis l.
2, an outer hook 24 that is fixed to the outer hook 24 with a bolt 23, the inner hook 20 that is housed in the outer hook 24, and a bobbin case 25 that is detachably mounted in the inner hook 20.
The bobbin 27 has a bobbin 27 wound around it and accommodated in the bobbin case 25.

A track groove 28 is formed on the inner peripheral surface of the outer hook 24, and the track groove 2
A rail 29 formed on the outer peripheral surface of the inner rotary hook is fitted into 8. The inner hook 20 is formed with a detent recess 30 into which the convex portion of the inner hook detent member 36 fixed to the machine body of the sewing machine is fitted, and the base end side of this detent recess 30, that is, the third
A needle drop hole 33 into which a vertically reciprocating needle 32 is inserted is formed in the vicinity of the left side of the drawing as indicated by an arrow 31. The needle thread T is inserted through the needle 32.
Is caught by a sword tip 35 provided on the outer hook 24. As the outer hook 24 rotates downstream in the outer hook rotation direction A1, the needle thread T caught by the sword tip 35 forms a needle thread loop, and slides over the outer peripheral surface of the inner hook 20 while passing over the thread. To do. The inner rotary hook 20 has a cylindrical portion 38 formed in a substantially right circular cylinder shape and formed with the rail 29, a flange 39 connected to one end of the cylindrical portion 38 in the axial direction l and protruding outward in the radial direction, and a cylinder. The bottom portion 40 is connected to the other end portion of the portion 38 in the direction of the axis l.

Referring to FIGS. 1 and 2, in the bottom portion 40, from the starting end P1 to the outer hook rotating direction A1 in the vicinity of a straight line L indicating a virtual plane connecting the central axis line 1 of the inner hook 20 and the movement path of the needle 32.
An opening 41 is formed across the downstream end P2. The starting end P1 is formed on the upstream side in the outer hook rotary direction A1 by an angle θ (P1) from the straight line L, and this angle θ (P
1) is 0 when the downstream side of the outer hook rotating direction A1 is the positive direction.
It is less than 10 degrees, preferably about -10 to -15 degrees. In addition, the terminal P2 has an angle θ (P
2) is formed only on the downstream side of the outer hook rotating direction A1.
This angle θ (P2) is selected to be about +150 degrees, for example. The opening 41 extending across the start end P1 and the end P2 is on the base end side of the inner rotary hook 20, that is, the second end.
The end surface 42 on the upper side of the drawing is connected to the end surface 44 extending in the circumferential direction through the step surface 43 smoothly extending through the angle θ (P1) + θ (P2).
The distance in the direction of the axis l, that is, the thickness d1 of the bridge 46 on which the stud 45 is erected is about 1.2 mm.

With the bobbin 27 accommodated in the inner hook 20 as described above, the flange 47 near the bottom portion 40 of the bobbin 27 is provided.
The end face 48 which is exposed to the outside through the opening 41 is substantially in the same plane as the plane perpendicular to the axis l including the end face 44. Further, in this state, the flange 47 of the bobbin 27 is
It is in contact with the bridging 46, whereby the lower thread 2
When 6 is pulled out, the bobbin 27 can be smoothly rotated without rattling. Moreover, as described above, the end surface 48 of the flange 47 near the bottom 40 is
Since it does not project outward from the end surface 44 of the inner hook 20, even if the needle thread T moves in the direction of the arrow m1 when the outer hook is rotated, the needle thread T may be caught on the flange 47. Absent. The operation of the needle thread T passing through the inner rotary hook 20 and the associated vertical full rotation rotary hook 21 will be described below with reference to FIGS. 5 and 6.

FIG. 5 is a front view for explaining the operation of the vertical full rotation rotary hook 21 according to the present invention, and FIG. 6 is a side view of the inner rotary hook 20 to which the bobbin case 25 is attached. First, in the state of FIG. 6 (1), the needle 32 and the sword tip 35 meet, and the sword tip 35 starts to capture the needle thread T. When the state shown in FIG. 5 (1) and FIG. 6 (2) is reached with the rotation of the outer hook 24 in the outer hook rotation direction A1 downstream, a needle thread loop T is formed by the sword tip 35. The needle thread loop T is gradually expanded in the vicinity of the lower end 49 of the inner hook 20 and the side surface 5 of the sword tip 35 extends in the direction of the axis l, that is, in the left-right direction of FIG.
0 (see FIG. 3) gradually expands toward the bottom portion 40 of the inner rotary hook 20.

When the outer hook 24 further rotates downstream in the outer hook rotation direction A1 to reach the state of FIG. 5 (2) and FIG. 6 (3),
The needle thread loop T is further expanded to a lower end portion 4 of the inner hook 20.
Pass 9 Balance side not shown, that is, FIG. 6 (3)
The needle thread T indicated by the arrow 51 is transferred from the outer peripheral surface 52 of the inner hook 20 to the end surface 44 of the bottom portion 40.

When the outer hook 24 further rotates further downstream in the outer hook rotation direction A1 to reach the state of FIG. 5 (3) and FIG. 6 (4),
The needle thread loop T is expanded to the maximum, and at this time, the arrow 5 on the balance side
The needle thread T indicated by 1 is located on the end surface 42 of the bridge 46 from the end surface 44 via the step surface 43 at a substantially intermediate position (first
It moves to a virtual plane including the straight line L and the axis l which are shown in FIG. The reciprocating vertical movement of the balance (not shown) and the rotation of the outer hook 24 are interlocked with each other, and the balance keeps the needle thread T until the needle thread loop T passing around the inner hook 20 is expanded to the maximum. In the feeding direction, that is, in the descending motion, the fifth
When the outer hook 24 further rotates to the downstream side in the outer hook rotation direction A1 than in the state shown in FIG. (3), the needle thread loop T is in a state of being left around the inner hook 20 in a sense.
The balance starts a raising operation to absorb the needle thread T. At the time of such a thread passing operation of the needle thread loop T,
That is, during the operation shown in FIG. 6 (2) to FIG. 6 (4), the needle thread loop T can transfer from the end face 44 to the end face 42 via the step face 43 extremely smoothly. There is no fear that the needle thread T will be caught in the inner hook and the movement of the needle thread T will not be stagnant, and accordingly, the needle thread T from the balance is
Does not cause yarn balls, looping, or yarn breakage.

Further, when the outer hook 24 is rotated to the downstream side in the outer hook rotation direction A1 from the state of FIG. 5 (3), the needle thread loop T is as shown on the right side of the figure, that is, the inner hook which is substantially circular as viewed from the front. Since it moves to the right side portion of 20, the needle thread loop can smoothly pass over the thread according to the needle thread absorbing operation of the balance.
At this time, although the needle thread loop T is stagnant until reaching (3) in FIG. 5, and the balance shifts to the absorption operation of the needle thread loop T, the needle thread loop is in the left half region of FIG. With T,
Although the thread ball, looping, or thread breakage may occur, in the present invention, the starting end P1 of the opening is provided on the upstream side in the rotary hook rotational direction A1 with respect to the straight line L, whereby each end face 42, 44 is formed. Since the spaces are smoothly connected via the stepped surface 43, the needle thread loop T does not stagnant as described above, and the needle thread loop T smoothly slides on the outer periphery of the inner hook 20 so that It is possible to smoothly guide and move along the end surface 44, the step surface 43, and the end surface 42. Therefore, it is possible to reliably prevent the occurrence of the yarn breakage described above.

FIG. 7 is a front view of the inner hook 20a according to an embodiment of the present invention, FIG. 8 is a plan view of the inner hook 20a shown in FIG. 7, and FIG. 9 is an inner view shown in FIG. It is a bottom view of the rotary hook 20a. In addition, the same reference numerals are given to the portions corresponding to the above-described configuration. It should be noted that the end P2a of the opening 41 formed in the bottom portion 40 of the inner rotary hook 20a is formed at a position of an angle θ (P2a) from the straight line L, and this angle θ
(P2a) is selected to be, for example, +180 degrees or more, preferably +195 degrees. By forming the starting end P1a and the terminating end P2a on the right side in FIG. 7 beyond the straight line L, the state shown in FIG. 6 (3) to FIG. 6 (5) is reached. Up to the end, the needle thread loop T can be transferred from the end face 44 to the end face 42 through the step face 43 while passing over the lower end portion 49 of the inner hook 20a, and accordingly, from the end face 44 to the end face. There is no risk that the needle thread T will be caught at the time of transferring to 42, and it is possible to move smoothly. By thus forming the terminal end P2a in addition to the starting end P1a, it is possible to more reliably prevent the needle thread T from stagnating and prevent the occurrence of thread breakage.

In the above-described embodiment, the lockstitch sewing machine having the vertical full-rotation rotary hook is described, but the present invention can be preferably implemented with respect to the rotary hook provided on the zigzag sewing machine.

EFFECTS OF THE INVENTION According to the present invention, a step surface is formed at the bottom of the inner hook, and the start end of this step surface is formed on the upstream side in the outer hook rotational direction with respect to the virtual plane including the axis of the inner hook and the movement path of the needle. As a result, the needle thread coup moving along this bottom part may pass over the lower end part of the inner hook and then transfer to the end face near the base end part of the bottom part of the inner hook via the step surface while reducing the diameter. Therefore, there is no possibility that the needle thread loop will be stagnant on the stepped surface, and the thread passing operation can be smoothly performed. As a result, it is possible to prevent the occurrence of yarn balls, looping, or yarn breakage.

Further, according to the present invention, since the end of the step surface is formed on the downstream side in the rotary hook rotational direction with respect to the virtual plane, after the needle thread loop passes through the lower end portion of the inner rotary hook, the needle thread loop is reduced in diameter. The needle thread can be transferred from the inside to the end surface near the base end through the step surface, which prevents the needle thread from stagnating in the vicinity of the step surface and facilitates smooth and easy thread crossing operation. It is possible to prevent the occurrence of yarn balls, looping or yarn breakage.

Further, according to the present invention, the start end of the step surface is formed on the upstream side in the rotary hook rotational direction with respect to the virtual plane of the inner rotary hook, and the end of the step surface is formed on the downstream side in the radial rotary hook with respect to the virtual flat surface. Since the needle thread loop moves through the step surface while reducing the diameter, there is no risk of the needle thread stagnating on the step surface, and therefore thread ball, looping or thread breakage is surely generated. Can be prevented. Moreover, according to the present invention, since it is only necessary to replace the inner rotary hook, there is an excellent effect that it can be implemented over a wide range in relation to the conventional rotary hook. Particularly according to the invention, the end face 48 of the flange 47 of the bobbin near the bottom of the inner hook
And the end surface 44 of the opening 41 are substantially in the same plane, and the end surface 42 of the bottom portion projects outward from the end surface 48 of the opening 41 by the thickness d1 of the bottom portion thereof. As a result, the excellent effect of further improving the threading of the needle thread loop is achieved.

[Brief description of drawings]

FIG. 1 is a front view of an inner rotary hook 20 showing a structure on which the present invention is based, FIG. 2 is a plan view of the inner rotary hook 20, and FIG. 3 is a vertical full rotary rotary hook 21 in which the inner rotary hook 20 is housed. Cross section,
4 is an overall perspective view of the vertical full rotation rotary hook 21 shown in FIG. 3, FIG. 5 is a front view for explaining the operation of the vertical full rotary rotary hook 21 according to the present invention, and FIG. 6 shows a bobbin case 25. FIG. 7 is a side view of the inner hook 20 installed, FIG. 7 is a front view of the inner hook 20a according to one embodiment of the present invention, FIG. 8 is a plan view of the inner hook 20a shown in FIG. 7, and FIG. FIG. 7 is a bottom view of the inner rotary hook 20a shown in FIG. 7, FIG. 10 is a front view of the inner rotary hook 1 provided in the conventional vertical full rotation rotary hook, FIG. 11 is a perspective view of the inner rotary hook 1, and FIG. FIG. 13 is a perspective view of the rotary hook 1 viewed from the rear side, FIG. 13 is a plan view of the internal rotary hook 1, and FIG. 14 is a bottom view of the internal rotary hook 1. 20, 20a ... Inner hook, 21 ... Vertical full rotation hook, 24 ...
Outer hook, 27 ... Bobbin, 32 ... Needle, 40 ... Bottom, 41 ...
Openings, 42, 44 ... End surfaces, 43 ... Step surfaces, P1, P1a
... Start end, P2, P2a ... End, L ... Straight line, T ... Needle thread

Claims (1)

[Claims] 1. An arc-shaped opening 41 is formed around the stud 45 at a bottom portion where an inner hook stud 45 is erected, and which extends smoothly to a bottom flange 47 of a bobbin housed in the inner hook. The starting end P1a of the opening 41 is formed at a first angle θ (P1a) of about 10 to 15 degrees on the upstream side in the outer rotary shaft rotation direction with respect to the virtual plane including the inner hook shaft line 1 and the movement path of the needle. Further, the end P2a of the opening 41 is formed with a second angle θ (P2a) of about 195 degrees on the downstream side in the rotary hook rotational direction with respect to the imaginary plane, and an end surface facing outward through the opening 41 of the flange 47. Four
8 is substantially in the same plane as the plane perpendicular to the axis l including the end surface 44 of the opening 41, and the bottom end surface 42 is the axis l by the thickness d1 of the bottom.
Full rotation hook of the sewing machine, which is characterized by protruding to the outside of the sewing machine.