JPH0268096A - Full rotary hook for lock stitch sewing machine - Google Patents

Abstract

PURPOSE:To take out a bobbin thread in a bobbin case in a constant direction, which is determined in advance, with desired preferable tension, to smoothly execute sewing work and to improve sewing quality by forming a groove to guide the bobbin thread in a tongue, which is formed in the bobbin case, and further providing a bobbin thread tension control means to control the tension of the bobbin thread which is guided along the groove. CONSTITUTION:A guide groove 35 is formed in a tongue 34 and width B1 of this guide groove 35 is selected to be almost equal with width B2 of a bobbin thread adjusting spring 44 of slightly larger. In the bobbin thread adjusting spring 44, a through hole 61, through which a rivet 60 is passed, is formed and the rivet 60 passed through the through hole 61 is passed through a through hole 62 which is formed in the tongue 34. Then, by calking a tip part 63, the bobbin thread adjusting spring 44 is fixed to the tongue 34. In the bobbin thread adjusting spring 44, a screw hole 65, to which a volt 64 for spring force adjusting is screwed, is formed. Thus, the entanglement or twining of the bobbin thread can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a full rotary hook that can be suitably implemented in, for example, a lockstitch sewing machine.

BACKGROUND OF THE INVENTION FIG. 6 is a front view of a conventional vertical full-rotation hook 3 showing a state in which a bobbin case 2 is attached to an inner hook 1, and FIG. 7 is a plan view thereof. Note that the outer hook is omitted in FIG. 6. In a vertical full-rotation hook 3 provided in a lockstitch sewing machine, etc., a hook locking recess 4 is formed in the inner hook 1, and a hook locking recess 4 has a base in order to prevent rotation of the inner hook 1. The fitting protrusion 7 of the inner hook rotation preventing member 6 whose end portion is fixed to the body of the sewing machine is fitted. Further, the inner hook 1 is formed with a lower thread guide groove 5 that opens facing the hook locking recess 4.

The bobbin case 2 houses a bobbin 9 around which a bobbin thread 8 is wound. Further, a lower thread tension spring 11 is attached to the outer peripheral surface of the bobbin case 2 with screws 10, and the lower thread 8 taken out from the bobbin 9 is connected to the outer peripheral surface of the bobbin case 2 and the outer peripheral surface of the lower thread tension spring 11. It is in a state where it is elastically sandwiched between the surface and the opposite surface. The lower thread tension spring 11 is configured to be able to apply appropriate tension to the lower thread 8 taken out from the bobbin 9 during sewing operations.

A rail 12 is formed on the outer circumferential surface of the inner hook 1, and the inner hook 1 is supported by the outer hook 13 while being fitted into a track groove 14 formed on the inner circumferential surface of the outer hook 13. . In this state, the rotation shaft 15 is rotated around the rotation axis by the arrow A.
When the outer hook 13 is rotated in the same direction, the outer hook 13 is rotated in the same direction.

In the second case, the inner hook 1 has a fitting protrusion 7 of the locking member 6.
is fitted into the locking recess 4, the end surface 16 of the outer hook 13 on the upstream side in the rotational direction A comes into contact with the end surface 17 of the fitting protrusion 7 on the upstream side in the rotational direction, and the inner hook 1 Rotation is prevented.

During such rotation of the outer hook, the upper thread 18 is rotated by the outer hook 1.
3 is caught by a tip (not shown) provided in the hook 3 to form an upper thread loop, and the thread loop is caught by the inner surface of the hook stopper recess 4 and the fitting protrusion 7
A seam is formed between the outer surface of the material and the outer surface of the material.

Problem to be Solved by Komei In this prior art, since the bobbin thread guide groove 5 is open facing the hook stop recess 4, the bobbin thread 8 is displaced in the circumferential direction during sewing, causing the bobbin thread 8 to displace the guide bar 5. There may be cases where it gets into the recess 4. The bobbin thread 8 passing through the recess 4 passes through the recess 4
As a result, an undesirably large tension is applied to the bobbin thread 8.

If such tension acts on the bobbin thread 8, thread breakage may occur, and high-quality stitches may not be formed.

As another prior art, in a sewing machine equipped with a fixed blade 19a and a movable blade 19b as shown by the imaginary line in FIG. Therefore, the bobbin thread 8 cannot be cut.

Therefore, an object of the present invention is to be able to take out the bobbin thread in the bobbin case in a predetermined direction with a desired tension without complicating the structure, thereby facilitating sewing work and improving the quality of the seams. To provide a full-rotation rotary hook for a lockstitch sewing machine which can be improved.

Means for Solving the Problems The present invention provides a recess in the inner hook on the downstream side in the direction of rotation of the outer hook than the hook locking recess provided in the inner hook, and a recess in the bobbin case. A full-rotation hook of a lockstitch sewing machine is fitted with a formed protrusion, and the protrusion has a groove for guiding the bobbin thread.

The present invention is characterized in that the protrusion is provided with a lower thread tension adjusting means for adjusting the tension of the lower thread guided along the groove.

According to the present invention, the inner hook is provided with a recess on the downstream side in the direction of rotation of the outer hook than the hook locking recess of the inner hook, and the protrusion formed on the bobbin case is fitted into this recess. A groove for guiding the bobbin thread is formed in this protrusion. The bobbin thread is guided along the groove to prevent undesired displacement during sewing operations. This makes it possible to guide the bobbin thread along a fixed passage path, thereby preventing undesired displacement of the bobbin thread during sewing and making it possible to take out the bobbin thread smoothly.

This prevents thread breakage and improves stitch quality.

Further, according to the present invention, the lower thread tension adjusting means is provided on the protrusion. As a result, the bobbin thread can be taken out with a desired tension during sewing, and therefore the sewing operation can be performed with good thread tension.

This makes it possible to improve the seam quality.

Embodiment FIG. 1 is a front view of a vertical full-rotation hook 20 showing a state in which a bobbin case 22 is attached to an inner hook 21 according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. Incidentally, in FIG. 1, the outer cover is omitted. A rotary shaft 25 that is rotationally driven around a horizontal axis of rotation is fixed to the outer rotary hook 24 having a raceway groove 23 formed on its inner circumferential surface.
A rail 26 formed on the outer peripheral surface of the inner hook 21 is fitted into the outer hook 24, and the inner hook 21 is supported by the outer hook 24.

The inner hook 21 is formed with a hook locking recess 29 into which a fitting protrusion 28 of an inner hook locking member 27 whose base end is fixed to the body of a sewing machine (not shown) is fitted. When the rotating shaft 25 is rotationally driven in the direction of arrow 30 around the rotational axis, the outer hook 24 is rotationally driven in the same direction. In this state, the outer hook rotation direction 30 of the hook locking recess 29
The upstream end surface 31 abuts and locks against the end surface 32 of the fitting protrusion 28, thereby preventing the inner pot 21 from rotating. Further, the end portion 42 of the bobbin case 22 includes a bottle 4.
A lock lever 47 is provided, which is attached to the stud 48 so as to be freely angularly displaceable around the axis of the stud 48. By operating the lock lever 47, the engaging piece 50 that engages with the engaging groove 49 formed in the stud 48 is moved. Thus, the bobbin case 22 can be attached to and removed from the inner hook 21 and replaced.

FIG. 3 is an enlarged perspective view of the bobbin case 22. Note that FIG. 3 is partially cut away for ease of illustration. Referring also to FIGS. 1 and 2, a recess 33 is formed near the downstream side of the rotation direction 30 where the fitting protrusion 28 of the inner hook 21 is formed. A protrusion 34 formed on the bobbin case 22 fits into it.

A guide groove 35 is formed in this projection 34, and a lower thread 37 wound around a bobbin 36 is fitted into the guide groove 35. The bobbin case 22 includes a substantially right cylindrical cylindrical portion 41 and a cylindrical portion 4.
The end portion 42 is formed so as to close one axial side of the end portion 1 . A notch 43 through which the bobbin thread 37 is inserted is formed in the cylindrical portion 41, and the notch 43 is formed by a bobbin thread tension spring 44.
The bobbin thread 37 taken out from the thread 3 is elastically pressed down and torn off.

This allows a preferable tension to be applied to the bobbin thread 37 during sewing.

No. 40 is an enlarged side view partially cut away to show the projection 34, and No. 5I2I is an exploded perspective view of the projection 34. As described above, the guide groove 35 is formed in the projection 34, and the width B1 of the guide groove 35 is approximately equal to or slightly larger than the width B2 of the lower thread tension spring 44. The lower thread tension spring 44 is formed with an insertion hole 61 into which the rivet 60 is inserted, and the rivet 60 inserted into the insertion hole 61 is inserted into the insertion hole 62 formed in the protrusion 34 and the tip 63 is caulked. , a lower thread tension spring 44 is fixed to the projection 34.

Further, the lower thread tension spring 44 is formed with a screw hole 65 into which a spring force adjustment bolt 64 is screwed. By inserting the bolt 64 into the bolt insertion hole 66 formed in the protrusion 34 and screwing it into the screw hole 65, and screwing the bolt 64 forward/backward, the spring 44 is fixed at a point near the rivet 60.
can be displaced. As a result, the tension of the bobbin thread 37 is reduced by threading the bolt 64 forward/backward while the bobbin thread shown by the imaginary line 37 in FIG. 5 is interposed between the protrusion 34 and the spring 44. Can be adjusted. The spring 44 displaced in this manner is integrally formed with a locking piece 68 bent in an inverted shape, and this locking piece 68 prevents the spring 44 from being undesirably removed from the protrusion 34. This can prevent them from becoming separated. Further, bent portions 69 are formed at the end of the spring 44 on the opposite side to the side where the insertion hole 61 is formed, and the six bent portions have a shape for holding the bobbin thread 67 in a fixed position. Guide groove 70
is formed. By forming such a guide groove 70, the bobbin thread 67 can be guided along a constant movement path.

In the vertical full-rotation hook 20 having the above-described configuration, when a sewing machine (not shown) is driven and the rotation shaft 25 is driven to rotate around its rotation axis, the outer hook 24 moves toward the arrow 30.
The needle 51 is reciprocated and moved up and down. With the outer hook 24 being rotationally driven in the direction of the arrow 30 in this manner, the fitting protrusion 28 of the inner hook locking member 27 is fitted into the locking recess 29 formed in the inner hook 21. Then, the end surface 32 of the fitting protrusion 28 comes into contact with the end surface 34 of the locking recess 29, and rotation of the inner hook 21 in the direction of arrow 30 is prevented. Furthermore, a protrusion 34 formed on the bobbin case 22 fits into a recess 33 formed on the inner pot 21, thereby preventing rotation of the bobbin case 22 about its axis.

In this state, the bobbin thread 37 taken out from the bobbin case 22 through the notch 43 from the bobbin 36 fits into the guide groove 35 from the lower side of the locking piece 68, and connects the spring 44 and the protrusion body 71. and is taken out upwardly from the guide groove 70. Such a guide j135.70 prevents the bobbin thread 37 from being undesirably displaced in the 2121st left-right direction or up-and-down direction, so that it can be let out along a fixed path. Therefore, the bobbin thread 37 does not become entangled or tangled with the needle 51 that moves up and down in a reciprocating manner.

Effects of the Invention According to the present invention, a recess is provided on the downstream side in the rotational direction of the outer hook than the hook locking recess of the inner hook, and the protrusion formed on the bobbin case is fitted into this recess. Because it is done,
You can position the inner shell and bobbin case,
Undesirable displacement of the bobbin case relative to the inner hook can be prevented.

Further, since a groove for guiding the bobbin thread is formed in the protrusion, the bobbin thread can be taken out in a fixed direction, thereby preventing the bobbin thread from getting tangled or tangled. At the same time, a desired amount of tension can be applied to the bobbin thread by the bobbin thread tension spring, thus making it possible to carry out sewing work with good thread tension, thereby improving the stitching quality. Moreover, the recess can be formed simply by cutting out the inner pot using a cutting device, and therefore, machining is easy. Moreover, since such an inner hook can use an existing inner hook and only the bobbin case needs to be replaced, the present invention can be widely implemented in conjunction with existing sewing machines.

4. Brief explanation of the drawings Figure 1 is a front view of a steam whistle according to an embodiment of the present invention. Figure 2 is a front view of a full vertical rotation 220, Figure 2 is a plan view thereof, and Figure 3 is an enlarged perspective view of the bobbin case 22. , FIG. 4 is an enlarged side view showing the protrusion 34 partially cut away, and FIG. 5 is an exploded perspective view of the protrusion 34.
Figure 6 shows the bobbin case 2 attached to the inner hook 1.
FIG. 7 is a plan view of a conventional vertical full-rotation motor.

20... Vertical full rotation hook, 21... Inner hook, 22.
...Bobbin case, 24...Outer or soil, 27...Inner rotary locking member, 28...Protrusion to fit, 29...Key lock recess, 33...Recess, 34...・Protrusion, 35...
Guide groove, 37...Bobbin thread, 44...Bobbin thread tension spring agent Patent attorney Number of strokes Keiichi Part 3 Figure 2 Figure 2 Prisoner

Claims (2)

[Claims] (1) A recess is provided in the inner hook on the downstream side in the direction of rotation of the outer hook than the hook locking recess provided in the inner hook, and a protrusion formed on the bobbin case is fitted into this recess, A full-rotation hook for a lockstitch sewing machine characterized by a groove formed in this protrusion to guide the bobbin thread. (2) The lockstitch sewing machine according to claim 1, wherein the protrusion is provided with a bobbin thread tension adjusting means for adjusting the tension of the bobbin thread guided along the groove. Full rotation hook.