JPH0133016Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a full-rotation hook for a lockstitch sewing machine. FIG. 1 is a plan view of a conventional full-rotation hook, FIG. 2 is a side view of the full-rotation hook shown in FIG. 1, and FIG. 3 is a side view of the full-rotation hook shown in FIG. 4 is a side view, and FIG. 4 is a rear view of the inner pot shown in FIG. 3. The outer hook 2 of the full rotation hook 1 is
It is rotated along the rotation running direction 3. This outer hook 2 houses an inner hook 4, and this inner hook 4
Rotation is prevented by an inner rotary locking member (not shown). The inner hook 4 is formed with a recess 5, and the recess 5 has an abutment surface 6 on the upstream side of the rotating travel 3 of the outer hook 2, which abuts against the rotation prevention contact surface of the inner hook rotation prevention member. It is formed. This contact surface 6 is a vertical surface 7 extending vertically in FIG.
has an angle β with respect to This angle β is selected, for example, from 6 degrees to 8 degrees. The needle thread loop passes through the gap between the abutment surface 6 and the detent abutment surface (not shown) via the path indicated by arrow 8. At this time, the contact surface 6 is configured to be inclined as described above so that the upper thread can easily pass through. However, with such prior art, when sewing a workpiece using a particularly thick thread, such as No. 8 thread (JIS standard), thread tightness is not good, and uneven thread tightness occurs. A situation arises where it is easy. To deal with this problem, we increased the tension of the thread. However, when the tension of the thread is increased in this way, the needle thread breaks and the fabric shrinks, reducing the workability of sewing work and, as a result, reducing the product value. ing. The purpose of this invention is to solve the above technical problems,
To provide a full-rotation hook that facilitates the passage of an upper thread. FIG. 5 is a front view of a full rotary hook according to an embodiment of the present invention, and FIG. 6 is a side view of an inner hook provided in the full rotary hook shown in FIG. The outer hook 11 of the full rotation hook 10 is fixed by a set screw 13 to a rotating shaft 12 having a horizontal axis. Outside hook 11
An inner pot 14 is housed in the . This inner hook 14 is prevented from rotating by an inner hook rotation preventing member 15. A recess 16 is formed in the outer end surface of the inner hook 14, and an inner hook contacting surface 17 is formed in the recess 16 on the upstream side of the rotational running direction 3 of the outer hook 11. This inner hook contacting surface 17 is inclined in a direction away from a horizontal surface 18 extending left and right in FIG. 5 as it approaches the inner hook rotation preventing member 15. This inclination angle α is selected, for example, from 6 degrees to 15 degrees. This inner hook abutment surface 17 also has the angle β described in the prior art. The inner hook rotation prevention member 15 that prevents the rotation of the inner hook 14 has a protrusion 1 that projects toward the recess 16.
9 is integrally provided. This inner hook rotation preventing member 15 is supported by a support member 20 so as to be movable upstream and downstream in the rotational running direction 3 of the outer hook 11 on the inner hook contacting surface 17 . The protrusion 19 provided on the inner rotary locking member 15 fits into the recess 16, and the outer peripheral surface of the protrusion 19 has a rotation-preventing contact surface 21 facing upstream in the rotational running direction 3.
is formed. This anti-rotation contact surface 21 is configured parallel to the horizontal surface 18. Since the rotation preventing contact surface 21 and the inner hook contact surface 17 are always in contact with each other, the inner hook 14 is kept stationary regardless of the rotation of the outer hook 11. The needle thread loop passes through the recess 16 from the back side of the page of FIG. 5 to the front side, as indicated by the arrow 22. At this time, the gap between the inner rotor contact surface 17 and the detent contact surface 21 is such that the inner rotor contact surface 17 is on the horizontal surface 18.
Since the gap is inclined at an angle α with respect to the rotary hook, the gap is larger than that in a conventional full rotary hook. In other words, in this embodiment, the space formed by the inner hook abutment surface 17 and the detent abutment surface is interpreted as constituting a thread guide opening for guiding the passage of the upper thread. Therefore, it becomes possible for the needle thread loop to pass through easily. Note that the inner hook abutting surface 17 in this embodiment is inclined at an angle β with respect to the vertical plane 7 as in the prior art, so in this embodiment, the inner hook abutting surface 17 The synergistic effect of the inclination relative to the horizontal plane 18 and the inclination relative to the horizontal plane 18 makes it easier for the needle thread loop to pass than in the past. A full-rotation hook according to the present invention and a conventional full-rotation hook

[Table] In this embodiment, since the upper thread loop can be easily passed through, the tension of the thread can be made smaller than in the conventional case. In particular, as is clear from Table 1, the effect is remarkable in thick yarns, for example, yarns with a thickness of No. 0 to No. 8 (JIS standard). As described above, according to the present invention, the abutment surface of the inner hook rotation stopper member extends in a direction perpendicular to the longitudinal direction of the inner hook rotation stopper member, and the inner hook contact surface approaches the rotation stopper member. As the upper thread is tilted away from the axis of rotation, a thread guide opening is formed between the inner rotor contact surface and the detent contact surface, thereby facilitating the passage of the upper thread. becomes possible.

[Brief explanation of drawings]

Figure 1 is a plan view of a conventional full rotary hook, Figure 2
The figure is a side view of the full-rotation hook shown in the first figure, FIG. 3 is a side view of the inner hook provided in the full-rotation hook shown in the first figure, FIG. 4 is a rear view of the inner hook shown in the third figure, and FIG. 6 is a front view of a fully rotary rotary hook according to an embodiment of the present invention.
The figure is a side view of the inner rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary rotary hook shown in FIG. 1, 10... Full rotation hook, 2, 11... Outer hook, 3... Rotating direction of outer hook, 4, 14...
Inner hook, 5, 16... Recess, 12... Rotating shaft, 1
7... Inner hook contact surface, 21... Anti-rotation contact surface,
α, β...Angle.

Claims (1)

[Claims for Utility Model Registration] An outer hook having an axis of rotation, an inner hook that is housed in the outer hook, and an inner hook rotation preventing member that prevents rotation of the inner hook, while the outer hook is rotating. The anti-rotation contact surface of the inner hook rotation preventing member that comes into contact with the contact surface of the inner hook is formed parallel to the rotational axis, and the contact surface of the inner hook contact surface on the upstream side of the rotational travel of the outer hook is: 1. A full-rotation hook for a sewing machine, characterized in that the hook is formed to be inclined in a direction away from the rotation prevention contact surface as it approaches the rotation prevention member.