JPH0135738Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Field of Use This invention relates to an overlock sewing machine that stitches the edges of cloth by operating a needle, an upper looper, and a lower looper in an interlocking manner.

Conventional Technology This type of overlock sewing machine is equipped with a sewing machine needle and separate upper and lower loopers.
There are cases where threads are threaded through each of the lower loopers to perform edge stitching with three threads per stitch, and cases where thread is threaded only through the lower looper and stitches are performed where two threads are threaded per needle. Conventionally, when using 3 threads per needle, the latch piece that is swingably provided along the upper looper is switched to a non-operating position, and the latching piece is moved to the non-operating position.
When using the main thread, the hooking piece is brought close to the upper looper, and the claw-like threading part provided at the tip is brought into contact with the upper looper, so that the threading part is engaged with the loop thread of the lower looper. (For example, Japanese Patent Publication No. Sho 56-13478, Japanese Utility Model Publication No. Sho 57-15386, Japanese Utility Model Publication No. 60-18771, and Japanese Utility Model Publication No. 60-18772).

Problems that the invention aims to solve As mentioned above, the conventional overlock sewing machine has
Separately from the upper looper, which has a threading hole for 3 threads per needle, a hook piece for switching is formed with a thread hook at the tip for 2 threads per needle, and this is attached to the upper looper. Since it was mounted so that it could swing either on itself or on a mounting base at the base of the upper looper, it not only had the manufacturing disadvantage of increasing the number of parts, but also made it easy to use it under unstable conditions. However, the structure is simple and the switching operation is easy.
There was a need for an overlock sewing machine that would ensure reliable operation of the upper looper.

Means for Solving the Problems Therefore, the present invention provides an overlock sewing machine in which a needle, an upper looper, and a lower looper are operated in an intersecting manner to hem the edge of a cloth. A thread hooking part is integrally formed on the upper looper itself so as to have an intersecting angle almost perpendicular to the threading hole in the cross-sectional direction, for catching the looped thread of the lower looper when overtaking two threads per needle. The present invention provides an overlock sewing machine in which the upper looper is mounted on a looper holder provided on the upper looper shaft so that the mounting angle corresponding to the crossing angle can be freely changed.

Function As described above, in the present invention, one upper looper is provided with a threading hole for three threads per needle and a thread hooking part for two threads per needle. Eliminates the need to attach one piece. In addition, the threading hole and the thread hooking part are formed perpendicularly to each other, and the mounting angle corresponding to the above-mentioned crossing angle can be changed freely via the looper holder provided on the upper looper shaft. Switching between the working position and the non-use state is reliably performed, thereby eliminating the drawbacks of the prior art.

Embodiments Examples of the present invention will be described below with reference to the drawings.

In the figure, 1 is a sewing machine needle, 2 is a lower looper, and 3 is an upper looper shaft, each of which is a member known in the art of overlock sewing machines. 4 is a looper holder provided on the upper looper shaft 3; 5 is an upper looper that is held through the looper holder 4 so that the mounting angle can be freely changed; and 6 is a looper holder provided through the tip of the upper looper 5. A threading hole 7 through which the upper looper thread is inserted when performing overlocking with three threads per needle has an intersection angle of approximately right angles in the cross-sectional direction of the threading hole 6 and the upper looper 5. This is a thread hooking part that protrudes from the side surface of the tip of the upper looper 6.

In the embodiment shown in FIGS. 1, 2, and 3, the looper holder 4 is provided with a cylindrical shaft hole 8 along the axial direction of the upper looper 5, and the base end of the upper looper 5 is loosely fitted into the looper holder 4. The operating lever 9 protruding from the middle side surface of the shaft hole 8 is brought into contact with the groove cam 10 formed on the rim of the shaft hole 8, while the base end of the upper looper 5 passing through the shaft hole 8 and the shaft hole 8 are brought into contact with each other. A coil spring 11 is installed between them, and recesses 10' are formed at both ends of the grooved cam 10 corresponding to the intersection angle between the threading hole 6 and the threading part 7.
It forms. When overlocking with three threads per needle, the operating lever 9 is engaged with one of the recesses 10' as shown in FIG. 1, and the upper looper thread is inserted into the threading hole 6. to drive the sewing machine. At this time, the thread hooking part 7 is located directly behind the upper looper 5 and is placed in a position where it does not interfere with the operations of the needle 1 and the lower looper 2 at all. (1st, 2nd
(See figure) When performing overlock stitching with 1 needle and 2 threads, move the operating lever 9 to the coil spring 1.
1, and then rotate it toward the front side to engage the concave portion 10' at the other end of the grooved cam 10. As shown in FIG. It changes its position approximately 90 degrees to the side surface and protrudes to a position where the loop of the lower looper yarn formed by the lower looper 2 is hooked.

Next, in the embodiment shown in FIG. 4, the grooved cam 10 of the above-mentioned embodiment is arranged on the circumferential surface of the upper looper 5 so that the recesses 10' at both ends protrude toward the base end of the upper looper 5. formed, and this grooved cam 10,
While engaging the inner end of the set screw 12 screwed into the looper holder 4, the shaft hole 8 is formed into a bottomed shape and the coil spring 11 is installed in the coaxial hole 8, and the upper looper 5 is gripped and the coil spring is removed. 11 and then rotated to engage the inner end of the set screw 12 with the recess 10' of either one of the grooved cams 10, and as in the previous embodiment, the threading hole is opened. This is a case where the positions of the thread hook 6 and the thread hooking part 7 are changed so that the overedge stitching can be switched between three threads per needle and two threads per needle.

Next, in the embodiment shown in FIGS. 5 and 6, the threading hole 6
This is a case where the present invention is implemented by using two upper loopers 5a and 5b, which are provided with a threading part 7, as a set.

That is, when one upper looper 5a is attached to the looper holder 4, the threading hole 6 of the upper looper 5a assumes the same position as shown in FIGS. You can perform overlock stitches using 3 threads per stitch by passing the upper looper thread through the . In this case, the upper looper 5a is held at a predetermined angle by having its base end formed in a semicircular cross section and fitting into the shaft hole 8 of the looper holder 4 whose lower end is symmetrically formed in a semicircular cross section. A chamfered portion 1 formed on the engagement surface (upper surface) of the inner end of the set screw 12 screwed into the looper holder 4.
3, the mounting position is firmly fixed. Note that 14 in the figure is a link that establishes the insertion depth of the upper looper. The other upper looper 5b has a thread hooking part 7 projecting from the side surface of the distal end, as shown in FIG. 6, with a phase difference of about 90 degrees from the threading hole 6 of the upper looper 5a. It has a semicircular section at the base end and a chamfered section 13 at the top at the same position as the upper looper 5a, and by loosening the set screw 12 and replacing it, it can be firmly attached to the looper holder 4 at a predetermined angle. While being held, it is possible to perform overedge stitching using two threads per needle in the same manner as in the embodiment.

Effect of the invention According to the invention configured as described above and adapted to be used as described above, when switching an overlock sewing machine to edge stitching with 3 threads per needle and 2 threads per needle, Since it is not necessary to attach a hook used for switching, the number of parts is reduced and manufacturing and assembly can be facilitated. In addition, the upper looper is provided with a thread hooking part having an intersecting angle almost perpendicular to the threading hole, and the threading part is attached to the looper holder on the upper looper shaft so that the mounting angle corresponding to the above intersecting angle can be changed freely. So,
In the case of three threads per needle using threading holes, the threading part is moved to a non-interfering position to avoid the operating range where the needle, lower looper, and upper looper operate in an intersecting manner with a minute clearance. It has practical effects such as easy switching operation and reliable use because the angle can be reliably maintained after switching.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Fig. 1 is a partially cutaway front view of the embodiment, Fig. 2 is a plan view of the same, and Fig. 3 is a state in which the mounting angle of the upper looper of the above has been changed. 4 is a partially cutaway front view of the embodiment, FIG. 5 is a partially cutaway front view showing an example of the usage state of the embodiment, and FIG. 6 is a partially cutaway front view of the upper looper of the embodiment when it is not in use. FIG. 1... Needle, 2... Lower looper, 3... Upper looper shaft, 4... Looper holder, 5, 5a, 5b
...Upper looper, 6...Threading hole, 7...Threading part, 8...Shaft hole, 9...Operation lever, 10...Cam groove, 10'...Recess, 11...Coil spring, 1
2... Set screw, 13... Chamfered portion, 14... Ring.

Claims (1)

[Claims for Utility Model Registration] (1) In an overlock sewing machine in which a needle 1, an upper looper 5, and a lower looper 2 are operated in an intersecting manner to stitch the edges of a cloth, A thread hook is provided on the upper looper 5 itself to hang the looped thread of the lower looper 2 when overtaking two threads per needle. 7 is integrally formed, and the upper looper 5 is attached to the looper holder 4 provided on the upper looper shaft 3 so that the mounting angle corresponding to the crossing angle can be freely changed. Rotsuku sewing machine. (2) The upper looper 5 consists of a set of two upper loopers 5a equipped with the threading hole 6 and an upper looper 5b equipped with the threading part 7,
Claim 1 of the above-mentioned utility model registration claim 1, characterized in that the upper loopers 5a and 5b of the set are attached to the looper holder 4 so that they can be used interchangeably.
Overlock sewing machine as described in section.