JPS6221267Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field This invention includes a pendulum needle bar mechanism in which the needle bar swings on one plane, and is arranged below the needle bar and synchronized with the movement of the needle bar. This invention relates to a sewing machine equipped with a horizontal hook body that is rotated by rotating the sewing machine.

Conventional technology Normally, in a sewing machine equipped with a horizontal hook, the gap between the tip of the needle and the needle, which is rotated in a plane parallel to the sewing work surface, is kept uniform, and a sufficient swing range of the needle is ensured during zigzag sewing. In order to do this, it has been common to use a so-called arc-type needle bar swinging mechanism that reciprocates in a circular arc concentrically with the central axis of the horizontal hook body. However, this arc-type needle bar swinging mechanism has a drawback in that it has a complicated configuration.

Furthermore, unlike the arc-type needle bar mechanism described above, the structure is simple, and if a pendulum-type needle bar mechanism is used in which the needle bar swings in one plane, the needle bar moves in an arc, whereas the needle bar swings in a single plane. Since the needle at the lower end performs linear motion, there is a drawback in that the amplitude range of the needle cannot be made sufficiently large during zigzag sewing.

Purpose This invention was made to eliminate the above-mentioned defects, and its purpose is to reciprocate the horizontal hook body in a plane perpendicular to the swing plane of the needle bar in a pendulum needle bar mechanism. Therefore, near the bottom dead center of the needle, the tip of the horizontal hook draws a nearly linear motion trajectory with a predetermined gap from the needle, and the amplitude range of the needle is almost limited by the trajectory of the tip. It is an object of the present invention to provide a new sewing machine that can sufficiently widen the amplitude range without causing problems.

Embodiment Hereinafter, an embodiment embodying this invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the upper surface of the bed of the sewing machine frame, together with the upper surface of the bed, constitutes a sewing work surface. A throat plate 1 is attached. Above the throat plate 1, a pendulum-type needle bar mechanism is provided in the arm portion of the sewing machine frame, which includes a needle bar (not shown) that swings on a plane P and is operated in conjunction with the main shaft of the sewing machine. , a needle 2 is attached to the lower end of the needle bar. Further, a hook drive shaft 3 extending in the horizontal direction and having its axis located on the swinging plane P of the needle bar is rotatably supported in the bed portion, and is rotated in conjunction with the main shaft of the sewing machine. ing. A hook bracket body 4 having a hollow shape with both front and rear surfaces open is rotatably supported on the hook drive shaft 3 at the rear thereof so as to be located below the throat plate 1. Hollow portion 4 of this hook bracket body 4
A support shaft 5 extending in a direction perpendicular to the hook drive shaft 3 is fixed to the hook bracket body 4 by a screw 5a so as to pass through the hook bracket body 4, and a horizontal hook body 6 attached to this support shaft 5 is attached to the hook drive shaft. 3 around the hook bracket body 4
It is designed so that it can rotate integrally with the

This horizontal hook body 6 is composed of an outer hook 7 that rotates around the support shaft 5 and an inner hook 8 whose rotation is restricted within the outer hook 7. Then, the outer hook 7 of the horizontal hook body 6 is rotated twice in one direction for each reciprocating movement of the needle 2 in a plane substantially parallel to the sewing work surface, and a lock stitch is formed on the work cloth. It's becoming like that. As shown in FIGS. 2 and 5, the outer pot 7 is formed into a substantially cylindrical shape with an open top, and
A shaft cylindrical portion 9 is provided protruding from its lower surface. A driven screw gear 10 and a cam surface 11 are provided on the outer periphery of this shaft cylinder portion 9.
A drive screw gear 1 is integrally formed on the shuttle drive shaft 3 so as to mesh with the driven screw gear 10.
2 is fixed by a screw 12a. and,
A gear transmission mechanism for transmitting the rotational motion of the hook drive shaft 3 to the horizontal hook body 6 is configured by both screw gears 10 and 12, so that the outer hook 7 rotates once while the hook drive shaft 3 rotates once. It's summery.

As shown in FIGS. 2, 4, and 5, a lace portion 13 is formed on the inner periphery of the upper part of the outer hook 7, and a part of the lace portion 13 has a tip 1 for catching the upper thread carried by the needle 2.
4 is formed. On the other hand, the inner hook 8 is formed into a substantially bottomed cylindrical shape with an open upper surface, and is adapted to accommodate a bobbin (not shown) around which a bobbin thread is wound in the center thereof. The inner hook 8 is housed in the outer hook 7 with the flange 15 of the inner hook 8 engaged with the race portion 13 of the outer hook 7 from above. A needle drop groove 16 is formed in the flange 15 so as to be located on the rotation locus of the tip 14, and an inclined surface 17 is formed so that the needle thread caught by the tip 14 during sewing operation of the sewing machine is removed. The thread ring follows this inclined surface 17 and can easily pass through the inner hook 8.

Behind the support shaft 5, on the upper surface of the hook bracket body 4, a regulating member 20 including a pair of locking pieces 18a, 18b and a cam follower 19 is supported so as to be swingable around the support shaft 21. 19
is engaged with the cam surface 11 of the outer hook 7 by a tension spring (not shown). Then, the cam surface 11
Based on the engagement of the cam follower 19 with the outer hook 7
When the regulating body 20 is swung around the support shaft 21 in time with the rotation of the locking pieces 18a, 18
b is a pair of locking grooves 22a, 2 formed in the flange 15 of the inner hook 8 on both sides of the needle drop groove 1b.
2b, the rotation of the inner hook 8 is regulated, and the free end of the upper thread and the lower thread let out by the upper thread loop are connected to each of the locking pieces 18a, 18b.
and each locking groove 22a, 22b.

Next, the configuration of the hook rotation position correcting device for controlling the rotation of the hook bracket body 4 about the hook drive shaft 3 will be explained. As shown in FIGS. 1 to 3, an operating arm 23 extending forward is integrally formed on the left side of the hook bracket body 4, and a forked portion 23a is formed at the tip thereof. In front of the operating arm 23, a pivot lever 25 is rotatably supported at its base end by a support shaft 24 provided in the bed portion so as to extend parallel to the hook drive shaft 3. A roller 26 serving as an engaging portion is rotatably supported near the base end of the rotating lever 25 and is engaged with the bifurcated portion 23a of the operating arm 23. A contactor 27 is provided protrudingly from the open end of the rotary lever 25, and a cam body 28 having an equal radius portion 28a and a recessed portion 28b is mounted on the hook drive shaft 3 on the outside of the operating arm 23. 29. Further, the operating phase of the cam body 28 is set so that the contact 27 engages with the recess 28b of the cam body 28 when the tip 14 captures the upper thread carried by the needle 2.

As shown in FIG. 2, the contact 27 of the rotary lever 25 is always engaged with the equal radius portion 28a of the cam body 28 by the spring force of the tension spring 30.
The horizontal hook body 6 on the hook bracket body 4 is held in a horizontal position based on the engagement between the roller 26 and the forked portion 23a so that the tip 14 can rotate in a plane parallel to the sewing work surface. It is becoming more and more like this. Also,
As shown in FIG. 3, when the contactor 27 is engaged with the recess 28b of the cam body 28 based on the spring force of the tension spring 30 as the cam body 28 rotates, the contact 27 is engaged with the recess 28b of the cam body 28. Based on the engagement with the portion 23a, the hook bracket body 4 is moved to the second position along with the operating arm 23.
The horizontal hook body 6 is swung clockwise in the figure by a predetermined angle, and in a plane perpendicular to the swiveling plane P of the needle bar.
is placed in a tilted position with its central axis tilted forward by an angle θ, and the tip 14 is aligned with the needle 2 as shown in FIG.
It is designed to draw an almost linear motion trajectory near the bottom dead center.

Next, to explain the operation of the sewing machine configured as above, when the sewing machine is driven, the needle bar swings within the preset maximum amplitude range of the needle 2, as is clear from FIG. Along with being
It is reciprocated in the vertical direction. During one reciprocating movement of the needle bar, the cam body 28 together with the hook drive shaft 3 is rotated twice clockwise in FIG. 2, and the outer hook 7 is rotated counterclockwise in FIG. 4 via the gear transmission mechanisms 12 and 10. Rotated twice. When the needle 2 is moved down to near the bottom dead center, the tension spring 30 is activated as the cam body 28 rotates.
Based on the spring force of the contact 27 of the rotating lever 25
is engaged with the concave portion 28b of the cam body 28, and due to the engagement between the roller 26 on the rotating lever 25 and the forked portion 23a of the operating arm 23, the horizontal hook body 6 is moved together with the hook bracket body 4 as shown in FIG. placed in a tilted position. At the same time, as shown by the chain line in FIG. 4, the tip 14 of the outer hook 7 draws a linear locus of motion almost parallel to the swinging plane P of the needle 2 at a position spaced apart by a predetermined distance from the plane P. The needle tip 14 can reliably catch the needle thread carried on the needle 2.

Also, when the needle 2 starts moving upward from the bottom dead center,
As the cam body 28 continues to rotate, the tension spring 30
After the contact 27 separates from the concave portion 28b of the cam body 28 against the spring force, it engages with the equal radius portion 28a, and due to the engagement between the roller 26 and the forked portion 23a, the hook bracket body 4, the horizontal hook body 6 is swung back to the horizontal position shown in FIG. 2, and at the same time, the tip 14 of the outer hook 7 traces an arcuate locus of motion as shown by the chain line in FIG. In this embodiment, when the needle 2 reaches near the top dead center, the contact 27 again engages with the recess 28b of the cam body 28, and the horizontal hook body 6 is again placed in the tilted position shown in FIG. be done. Therefore, by continuously performing the above operations, zigzag stitches are formed on the work cloth.

In addition, in this embodiment, since the axis of the shuttle drive shaft 3 is located on the swinging plane P of the needle bar, the tip of the hook when the horizontal hook body 6 swings is
4 can be reduced in the vertical direction, and the horizontal displacement can be increased, and the tip 14 can be brought sufficiently close to the needle 2 when capturing the upper thread.

Note that this invention is not limited to the above embodiment, and for example, the cam body 28 and the contactor 2
7, it is also possible to arbitrarily change the configuration of each part without departing from the spirit of this invention, such as by providing a cam body having a grooved cam of a predetermined shape and a contact that can be engaged with the grooved cam. be.

Effects As detailed above, this invention enables the hook bracket body, which supports the horizontal hook body rotatably around the axis perpendicular to the horizontal hook drive shaft, to be rotatable around the axis of the hook drive shaft. a gear transmission mechanism is provided between the hook drive shaft and the hook body in order to transmit the rotational movement of the hook drive shaft to the hook body, and the hook body is perpendicular to the swinging plane of the needle bar. A hook rotation position correction device is provided for rotationally controlling the hook bracket body so as to reciprocate within a plane, and the correction device includes:
A cam body attached to the hook drive shaft, a contactor that is rotatably supported around an axis parallel to the axis of the hook drive shaft and engages with a contactor and a portion of the hook bracket body that is subjected to the cam action of the cam body. By including a rotary lever having an engaging portion that engages with the needle, the tip of the horizontal hook body draws a substantially linear movement trajectory with a predetermined distance from the needle near the bottom dead center of the needle. This provides an excellent effect in that the amplitude range of the needle is hardly restricted by the locus of motion of the tip, and the amplitude range can be made sufficiently large.

[Brief explanation of the drawing]

Figure 1 is a front sectional view showing the main parts of a sewing machine that embodies this idea, Figure 2 is a side sectional view showing the horizontal hook body placed in a horizontal position, and Figure 3 is a horizontal sectional view showing the horizontal hook body being tilted. FIG. 4 is a plan view of the outer hook, and FIG. 5 is an exploded perspective view of the horizontal hook body and the regulating body. Hook drive shaft...3, Hook bracket body...4, Horizontal hook body...6, Driven screw gear...10, Drive screw gear...12 (the above 10 and 12 constitute a gear transmission mechanism), Rotating lever...25, roller as an engaging part...26, contact...27, cam body...28.

Claims (1)

[Claims for Utility Model Registration] 1. The needle bar is equipped with a pendulum needle bar mechanism that swings on a plane P, and is arranged below the needle bar and rotates in synchronization with the movement of the needle bar. In a sewing machine equipped with a horizontal hook body 6, the hook body 6 is rotatably supported around the axis of a horizontal hook drive shaft 3 for rotationally driving the hook body 6, and the hook body 6 is orthogonal to the hook drive shaft 3. a hook bracket body 4 that is rotatably supported around an axis; and a hook bracket body 4 provided between the hook drive shaft 3 and the hook body 6;
gear transmission mechanisms 10 and 12 for transmitting the rotational motion of the hook drive shaft 3 to the hook body 6; A rotary hook rotation position correcting device for controlling the rotation of the bracket body 4 is provided, and the hook rotation position correcting device is connected to a cam body 28 attached to the hook drive shaft 3 and a hook rotation position correcting device for controlling the rotation of the hook drive shaft 3. a rotary lever 25 that is rotatably supported around an axis parallel to the axis and has a contact 27 that receives the cam action of the cam body 28 and an engaging portion 26 that engages with a part of the hook bracket body 4; A sewing machine comprising: 2. The sewing machine according to claim 1, wherein the hook drive shaft 3 is arranged such that its axis is located on a swing plane P of the needle bar.