JPS6067Y2 - Sewing machine looper drive device - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a looper drive device for a sewing machine.

Conventionally, with looper drive devices such as edge stitch sewing machines and hem rimming machines, it is difficult to finely adjust the length of the looper's elliptical locus in the short axis direction (apoid amount), and it is difficult to always keep the distance between the needle and the looper at an appropriate distance. Also, when changing the apoid amount, the spacing does not change symmetrically around the long axis, so for example, if you narrow the gap between the needle and the looper when the looper moves forward, the gap between the needle and the looper during the backward movement will change. The interval between becomes wider.

For this reason, there have been cases where the loop formed by the needle cannot be captured by the looper, or where the needle cannot be inserted between the loops formed by the looper.

Therefore, there is a drawback that skipped stitches occur in the seams, resulting in defective sewn products.

The purpose of this invention is to provide a looper drive device for a sewing machine that eliminates such drawbacks.

An embodiment of this invention will be described below based on the drawings.

In Fig. 1, 1 is the cloth feeding direction (from the front of the drawing to the back)
It is a looper shaft whose axis is perpendicular to the machine frame 2, and is loosely fitted into two bushings 3A and 3B which are arranged opposite to each other in the machine frames 2 and 2 so as to be freely rotatable and slidable.

Reference numeral 4 denotes a looper extending in a direction crossing the cloth feeding direction, and is disposed at the end of the looper shaft opposite to the side surface of a needle (not shown) that moves up and down provided on a needle bar (not shown). .

Note that 4a is a hole made at the tip of the looper 4.

5 is a two-pronged rod, and a bush 3 supports the looper shaft 1.
A bifurcated arm 5a rotatably supported by A, and the bush 3
It consists of a support rod 5b rotatably supported by B, and a slide pin 5d which is horizontally suspended between the bifurcated arm 5a and the support rod 5b, is fixed to the looper shaft 1, and has its tip inserted into the elongated hole H.

Therefore, the swinging of the two-pronged rod 5 causes the looper shaft 1 to swing.

In FIG. 2, reference numeral 6 denotes a drive shaft rotatably supported on the machine frame parallel to the looper shaft 1, and is driven in conjunction with a needle bar drive mechanism (not shown).

Reference numeral 7 denotes an eccentric double cam fixed to the drive shaft 6, which is eccentrically fixed to the drive shaft 6 at its outer periphery.

It consists of a first eccentric cam 7A and a second eccentric cam 7B detachably supported on the outer periphery of the first eccentric cam 7A so as to be eccentric to the axis of the first eccentric cam 7A and the axis of the drive shaft 6.

Reference numeral 8 denotes a known driving element that causes the looper shaft 5 to slide in synchronization with the vertical movement of the needle, that is, to reciprocate the looper shaft in the horizontal direction (arrow Y direction) in FIG. The L school 9 is rotatably supported and the L school 9 is rotatably supported at the tip of the L school 9.
A roller 11 is disposed perpendicularly to the looper shaft 1 between the slide pin 5d and a retaining ring 10 that is fitted and fixed to the looper shaft 1 at a distance, and a spherical journal 12 is supported at the other end of the L academy 9. , a spherical journal 12 , and a crank mechanism 13 that connects the drive shaft 6 .

Note that this driving element is not limited to the one shown in the drawings as long as it can convert the rotation of the drive shaft 6 into a sliding movement (horizontal movement in the drawing) of the looper shaft 5.

Next, the operation of this invention will be explained.

When the drive shaft 6 is rotated by the motor, the needle bar drive mechanism (
(not shown), the needle bar and needle move up and down.

Along with this, the crank mechanism 13 moves up and down, and the L academy 9 makes a reciprocating angular movement via the spherical journal 12.

Then, the looper shaft 5 reciprocates in the axial direction on each of the rollers 11 supported at the tip of the L school 9.

The slide pin 5d fixed to the looper shaft 5 also slides back and forth in the elongated hole H in the axial direction.

At the same time, the eccentric double cam 7 fixed to the drive shaft 6 rotates due to the rotation of the drive shaft 6.

Therefore, the two-pronged arm 5a of the eccentric double cam 7 fitted with the second eccentric cam 7B reciprocates around the bush 3A at a desired rotation angle.

As a result, the guide rod 5C also makes a reciprocating angular movement, so that the looper shaft 5 also reciprocates about its axis via the slide pin 5d.

As a result, the tip of the looper 4 alternately advances and retreats on the front and back sides of the needle N, which moves up and down due to the combined movement of the movement in the axial direction and the swinging around the axis, forming an ellipse as shown in Fig. 3. It moves and cooperates with the needle N to form stitches such as overlock stitches.

Stitches are formed as described above, but if the diameter of the needle N needs to be made thicker or thinner depending on the type of fabric, the looper 7 must be changed without changing the apoid amount l. may come into contact with the needle N, or the loop may not be captured.

In this case, if the mounting position of the second eccentric cam 7B and the first eccentric cam 7A of the eccentric double cams 7 is changed, the drive shaft 6
Since the eccentric distance of the second eccentric cam 7B about the center changes slightly, the swing angle changes, and as a result, the apoid amount l is accurately changed.

In this embodiment, the two-pronged rod 5 and the looper shaft 5 are
1, the elongated hole H and slide pin 5d were used, but the forked arm 5a was fixed to the looper shaft 1, and the forked arm 5a was connected to the second
If the eccentric cam 7B is provided so as to be slidable thereon, the elongated hole H and the slide pin 5d are not necessary.

Further, in the embodiment, the looper shaft 6 and the looper were perpendicular to the cloth feeding direction, but in a sewing machine where the looper shaft 6 is installed parallel to the cloth feeding direction, the looper must be installed perpendicular to the looper shaft 6. There is.

As described above, according to this invention, since an eccentric double cam is used to swing the looper, it is possible to minutely change the length of the looper's elliptical locus in the short axis direction (apoid amount), and as a result, the looper Since the distance between the needle and the needle can be finely adjusted and the distance can always be maintained at an appropriate distance, the looper does not catch the loop formed by the needle, resulting in a good sewn product with no skipped stitches. This has the effect of being able to obtain the following.

In addition, since the eccentric double cam causes the apoid amount to change symmetrically around the long axis of the ellipse, even if the apoid amount is changed, the distance between the looper and the needle during the forward and backward movements of the looper remains unchanged. If one decreases, the other also decreases, making it possible to obtain a better sewn product with no skipped seams.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of an embodiment of the device of this invention;
The figure is a sectional view taken along the line A--A in FIG. 1, and FIG. 3 is a diagram showing the locus of the tip of the looper. 1... Looper axis, 4... Looper,
6... Drive shaft, 7... Eccentric double cam,
8... Drive element.

Claims (1)

[Scope of Claim for Utility Model Registration] A looper shaft supported to be swingable about a fixed axis relative to the machine frame and movable along the axis, and having a looper fixed to one end intersecting the cloth feeding direction; A two-pronged rod supported on the looper shaft and having two pronged parts at its free end, a drive shaft that is supported rotatably about a fixed axis relative to the machine frame and rotates in one direction in conjunction with the motor; A first eccentric cam fixed eccentrically to its axis on the outer periphery;
A second eccentric cam and a second eccentric cam detachably supported on the outer periphery of the eccentric cam so as to be eccentric to the axis of the first eccentric cam and the axis of the drive shaft; A looper drive device for a sewing machine, comprising a drive element interposed between a looper shaft.