JPS6112049Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a full vertical rotation hook for a sewing machine, and more particularly to an improvement of an inner hook holding member fixed to an outer hook for storing and holding the inner hook in the outer hook.

FIG. 1 is a cross-sectional view showing an outer hook of a prior art vertical full-rotation hook for high-speed zigzag stitching, and FIG. 2 is a cross-sectional view taken along the cutting plane line--line in FIG. 1. Below the throat plate 1, an outer hook 2 is driven to rotate around a horizontal axis in the direction of arrow 3. During sewing, the needle moves up and down from the needle hole 4 of the throat plate 1, and the upper thread 5
A seam is formed by a lower thread (not shown) and a lower thread (not shown).

3 is a front view of the outer hook 2 in FIG. 1 with the needle thread 5 omitted, and FIG. 4 is a plan view of the outer hook 2. The outer hook 2 is constructed by fixing an inner hook holding member 7 to an outer hook main body 6 with screws 8. This inner hook holding member 7 forms a track groove 9 in a plane perpendicular to the axis of the outer hook 2 together with the outer hook body 6 . A rail formed on the outer periphery of the inner hook is fitted into the raceway groove 9, and the outer hook 2 is driven to rotate while the inner hook is prevented from rotating. The inner hook pressing member 7 includes a bobbin thread guide piece 10 and a thread ring absorbing piece 1.
1 in the radial direction of the outer hook 2 (i.e., in FIG.
2 and 3), and as shown in FIG. 4, the thread ring absorbing piece 11 is located directly below the bobbin thread guide piece 10. This yarn ring absorbing piece 11
serves to absorb and eliminate slack in the needle thread 5 after the loop of the needle thread 5 has come off the tip 12.

In such prior art, the bobbin thread guide piece 10 and the thread ring absorbing piece 11 are respectively arranged radially outward and inward within a plane perpendicular to the axis of the outer hook 2. The distance d1 between the tip 12a and the radially inward inner peripheral edge 11a of the yarn ring absorbing piece 11 is large. Therefore, the upper thread 5 is the thread ring absorbing piece 1.
The amount of thread loop when it comes out from thread 1 is large, and therefore, looping and thread breakage due to so-called fraying of the upper thread 5 are likely to occur. Also, the bobbin thread guide piece 1
0 and the thread ring absorbing piece 11 are arranged radially outward and inward within a plane perpendicular to the axis of the outer hook 2, as is clear from FIG. The upper thread 5 engaged with the thread ring absorbing piece 11 is
It is bent largely to the left in FIG. 2 from the needle hole 4 by an angle θ1 with respect to the vertical line 32. For these reasons, the upper thread 5 engaged with the thread ring absorbing piece 11 becomes difficult to come off from the thread ring absorbing piece 11.
Furthermore, the distance 1 between the branch point 22a of the bobbin thread guide piece 10 and the thread ring absorption piece 11 and the tip 12a of the tip 12 is
Since the loop of the needle thread 5 is long, the loop of the locked upper thread 5 immediately separates from the branching point 22a, and the time it remains on the thread loop absorbing piece 11 becomes longer. The loop of the upper thread 5 on the thread ring absorbing piece 11 is pulled excessively in the direction of rotation of the outer hook due to friction, so that the loop of the upper thread 5 is removed from the upper thread guide piece 11.
When the loop exits, the loop tends to become large. As a result, so-called looping or thread breakage occurs, resulting in a decrease in sewing performance. Regarding this, a similar problem occurs in, for example, the vertical full-rotation hooks disclosed in Utility Model Application Laid-Open No. 56-62784 and Japanese Patent Application Laid-Open No. 49-111745.

An object of the present invention is to provide a vertical full-rotation hook that allows smooth movement of the needle thread, thereby improving sewing performance.

In the present invention, a bobbin thread guide piece and a thread ring absorbing piece that extend upward in the direction of rotation of the outer hook are attached to the inner hook holding member fixed to the outer hook for storing and holding the inner hook in the outer hook. They are formed on the rotating shaft side and the bobbin case side of the outer hook so as to be shifted in the axial direction, and the branching point of the thread ring absorbing piece and the bobbin thread guide piece is located at the center between the tip and the outer hook raceway thread slip-out part. Bring it close to the tip of the blade, and place it on the bobbin case side surface of the thread ring absorbing piece.
The vertical full-rotation hook is characterized in that a slope is provided such that the thickness in the axial direction of the outer hook decreases from the branching point toward the distal end side of the thread ring absorbing piece.

FIG. 5 is a front view of an embodiment of the present invention. An inner hook 31 is housed and held in the outer hook 2 of the vertical full rotation hook for high-speed zigzag stitching, and a bobbin case 15 is attached to the inner hook 31.

FIG. 6 is a sectional view showing the outer hook 2, and FIG. 7 is a sectional view taken along the cutting plane line - in FIG. The outer hook 2 is constructed by fixing an inner hook holding member 17 to an outer hook body 6 with screws 8. A needle moves up and down through the needle hole 4 of the throat plate 1, whereby a stitch is formed by the upper thread 5 and a lower thread (not shown). Outer hook body 6 and inner hook holding member 17
The rail formed on the outer periphery of the inner hook 31 fits into the track groove 9 formed by the outer hook 2.
is rotated in the direction of arrow 3, and the inner hook 3 is stopped from rotating and remains stationary.

8 is a front view of the outer hook 2 with the upper thread 5 of FIG. 6 omitted, and FIG. 9 is a plan view of the outer hook 2. The inner hook pressing member 17 has a bobbin thread guide piece 18.
and a yarn ring absorbing piece 19 are formed. The lower thread guide piece 18 is located on the upper side (sixth
8, to the left in FIG. 8, and to the right in FIG. 9). The thread ring absorption piece 19 also extends in the direction of rotation 3 of the outer hook 2 . The bobbin thread guide piece 18 is located on the rotating shaft 20 side of the outer hook 2 (left side in Figure 7, lower side in Figure 9), whereas the thread ring absorption piece 19 is located on the bobbin case 15 side (left side in Figure 7). (on the right side of Figure 9),
In this way, the bobbin thread guide piece 18 and the thread ring absorbing piece 19
is shifted in the axial direction of the outer hook 2 (the left-right direction in FIG. 7, the up-down direction in FIG. 9). In the inner hook holding member 17, from the base end of the thread ring absorbing piece 19 to the tip end 19a
The radially inward inner circumferential edge 21 is formed so that the end 19a side of the thread ring absorbing piece 19 is tapered. The surface 19b of the thread ring absorbing piece 19 on the bobbin case side (upper side in FIG. 9) is formed so as to approach the rotating shaft 20 side as it approaches the tip 19a. In other words, this surface 19b
It is inclined toward the tip 19a on the rotation axis 20 side with respect to a plane perpendicular to the rotation axis. Lower thread guide piece 1
8 and the branch point 22 of the thread ring absorbing piece 19, and the tip 1
2 is separated by a distance 2 in the circumferential direction of the outer hook 2. Inner peripheral edge 21 near the tip 12a of the sword point 12 and the tip 19a of the yarn ring absorbing piece 19
is separated by d2 in the radial direction of the outer hook 2.

FIG. 10 1 shows a state in which the upper thread 4 has separated from the tip 12 and is locked in the thread ring absorption piece 19, and FIG. show.

According to the embodiment described above, the bobbin thread guide piece 18 and the thread ring absorbing piece 19 are offset in the axial direction of the outer hook 2, so that the inner circumferential edge 21 near the tip 19a of the thread ring absorbing piece 19 is displaced from the outer hook 2. It becomes possible to position it radially outward of the rotary hook 2. Therefore, the angle θ2 formed by the needle thread 5 locked on the thread ring absorbing piece 19 with respect to the vertical line passing through the needle hole 4 can be made relatively small as shown in FIG. 7, and the needle thread absorbing piece 19 The loop of the upper thread 5 that has come off can also be made smaller. This angle θ2 also becomes smaller because the surface 19b is inclined toward the rotating shaft 20 as it approaches the tip 19a. Therefore, the upper thread 5 easily comes off from the thread ring absorbing piece 19. Furthermore, the branching point 22 between the upper thread absorbing piece 19 and the lower thread guiding piece 18 is selected near the middle between the tip 12a of the tip 12 and the thread dropout part 23 of the track groove 9 of the outer hook 12, that is, as shown in FIG. By shortening the distance 2 (3/2=2) in , the needle thread 5 locked on the needle thread absorbing piece 19 has almost no time to stay on the needle thread absorbing piece 19, and the needle thread 5 remains on the needle thread absorbing piece 19, As the outer hook 12 rotates, the outer hook naturally comes off from the upper thread absorbing piece 19 near just below the needle hole without being excessively pulled in the rotating direction, and the drawbacks of the prior art can be solved. Therefore, so-called looping does not occur, thread breakage is eliminated, and sewing performance is improved.

The present invention can be widely implemented in connection with not only high-speed zigzag hooks but also other vertical full-rotation hooks.

As described above, according to the present invention, the lower thread guide piece and the upper thread absorbing piece of the inner hook holding member are formed to be shifted in the axial direction of the outer hook, so that the thread ring absorbing piece is attached to the lower thread guiding piece. The present invention enables the needle thread loop to be located radially outward of the outer hook regardless of its position, so that the loop of the needle thread is located directly below the needle hole, and the loop of the needle thread is largely inclined as in the prior art. Then it disappears. Further, the branching point is adjusted so that the needle thread loop comes into contact with the branching point between the bobbin thread guide piece and the thread ring absorbing piece until the loop of the upper thread that is locked in the thread ring absorbing piece reaches the vicinity just below the needle hole. Since it is placed close to the tip of the tip, the needle thread loop is prevented from being pulled excessively in the direction of rotation of the outer hook, and it becomes easier to come off the thread loop absorbing piece. In this way, the needle thread moves smoothly and sewing performance is improved.

In particular, in the present invention, the branching point between the thread ring absorbing piece and the bobbin thread guide piece is moved to the midpoint between the tip and the outer hook groove thread slip-out section, that is, the central position between the tip and the outer hook loop thread pull-out section. Since I brought it close to the tip of the blade, the upper thread has almost no time to stay on the upper thread absorbing piece.
Therefore, due to the rotation of the outer hook, the thread is not pulled excessively in the direction of rotation of the outer hook, and it naturally comes off from the upper thread absorbing piece near the needle hole. This eliminates looping, eliminates thread breakage, and improves sewing performance.

Furthermore, in the present invention, a slope is provided on the bobbin case side surface of the thread ring absorbing piece so that the thickness in the outer hook axis direction decreases from the branching point toward the tip side of the thread ring absorbing piece. As shown in FIG. 7, it is possible to reduce the angle θ2 that the upper thread, which is secured to the thread ring absorption piece, makes with respect to the vertical line passing through the needle hole. This makes it easier for the upper thread to come off the thread loop absorbing piece. In other words, as the outer hook rotates in the direction shown by arrow 3 in FIG. It is possible to significantly reduce the frictional force due to This makes it easier for the needle thread to come off the thread ring absorbing piece. Therefore, the needle thread moves smoothly and sewing performance is improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a prior art outer hook 2, FIG. 2 is a sectional view taken from the cutting plane line - in FIG. 1,
3 is a front view of the outer hook 2 in FIG. 1 with the upper thread 5 omitted; FIG. 4 is a plan view of the outer hook 2;
The figure is a front view of one embodiment of the present invention, FIG. 6 is a sectional view showing the outer hook 2, and FIG. 7 is a cross-sectional view of FIG. 6.
8 is a front view of the outer hook 2 with the needle thread 5 in FIG. 6 omitted, and FIG. 9 is a sectional view of the outer hook 2 as seen from
FIG. 10 is a sectional view for explaining the operation of an embodiment of the present invention. 2... Outer hook, 3... Inner hook, 15... Bobbin case, 17... Inner hook holding member, 18... Lower thread guide piece, 19... Thread ring absorption piece, 20... Rotating shaft,
31...Rotation direction.

Claims (1)

[Scope of utility model registration request] A bobbin thread guide piece and a thread ring absorbing piece extending upward in the direction of rotation of the outer hook are shifted in the axial direction of the outer hook onto an inner hook holding member fixed to the outer hook for storing and holding the inner hook in the outer hook. The outer hook is formed on the rotating shaft side and the bobbin case side, respectively, and the branching point of the thread ring absorbing piece and the bobbin thread guide piece is extended to the tip side to near the center position between the tip and the outer hook raceway thread slip-out part. , and the bobbin case side surface of the thread ring absorbing piece is provided with a slope such that the thickness in the outer hook axis direction decreases from the branching point toward the distal end side of the thread ring absorbing piece. Full vertical rotation hook.