JPH031039B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a looper drive device for an overlock sewing machine, and in particular, the present invention relates to a looper drive device for an overlock sewing machine, and particularly to a looper drive device that uses a needle that moves up and down and a single looper that is driven in synchronization with the up and down movement of the needle. The present invention relates to a looper and a looper driving device in a sewing machine that is equipped with the sewing machine to form an overlock stitch.

(Prior Art) In general, in an overlock sewing machine, a needle bar with a needle fixed to its tip is supported on a sewing machine frame so as to be movable up and down from the lower front in the feed direction to the upper side in the feed direction.

The locus of the looper tip of the looper drive device of a conventional overlock sewing machine that uses one looper is as shown in Fig. 17, with the upper surface of the throat plate indicated by X-X and the needle tip indicated by Y-Y. With respect to the vertical movement position, the looper synchronizes with the vertically moving needle, and moves from the needle thread capture position that intersects the needle position below the throat plate to the needle above the throat plate via the side of the throat plate. In order to cross the looper thread and bring it to the upper position where it is captured by the needle, the looper needs to move horizontally as well as vertically.

For this reason, in conventional overlock sewing machines,
It is equipped with a needle vertical movement generation source and a looper drive generation source that drive the needle bar on which the needle is attached, and stitch formation is achieved by synchronizing their drives.

Among these, the looper side uses a single swinging and rotating drive source as a looper drive device, in which the looper is attached to a looper drive mechanism connected to the drive source, and combines vertical and horizontal movements of the looper. The motion trajectory is as shown in FIG.

Since the looper drive device is driven by rocking rotation, the two ends of the looper movement are a trajectory from the lower bottom dead center position b to the upper top dead center position a, and a trajectory from the top dead center position a to the bottom dead center position. The trajectory toward b moves on the same trajectory.

In general, the looper trajectory is such that the top dead center position a, where the looper is at its uppermost left, is above the needle to ensure that the needle captures the looper thread held by the looper when descending from the needle's top dead center. It is generally set at 10 to 20 degrees in order to start the downward movement later than the dead center phase (generally considered to be 0 degrees at the spindle rotation phase).

Therefore, the bottom dead center position b, where the looper is most leftward and downward, is about 190 degrees in the main shaft rotation phase, which is 10 to 20 degrees behind the 180 degrees bottom dead center phase of the needle.

The phase in which the looper crosses the needle and captures the needle thread when it rises from the bottom dead center position b is around 220 degrees, which is approximately 30 degrees after the bottom dead center (190 degrees), as shown by R in the figure. Then, the phase at which the tip of the looper intersects the needle when descending from top dead center a is at the same position as R, which is around 160 degrees, about 30 degrees before bottom dead center (190 degrees).

Assuming that the bottom dead center phase of the needle is 180 degrees, the looper captures the first position when 30 degrees have passed when the needle rises.
In contrast to the needle position as shown in Figure 6, the intersection of the looper tips as the needle descends is 20 degrees before the bottom dead center of the needle, resulting in a lower needle position as shown in Figure 15. The loopers intersect at the position where the needles are lower than when they are raised.

The crossing state of the looper tip with respect to the needle is set so that there is very little crossing gap with respect to the edge part of the needle, as shown in FIG. 16, in order to prevent stitch skipping when the needle thread is captured.

As mentioned above, when the needle in Fig. 15 is captured (in Fig. 16)
If the looper is in a lower position than in the figure), the tip of the looper will pass above the edge of the needle, which may interfere with the needle and cause noise, breakage, or bending of the needle.

(Objective) The present invention has been made in order to eliminate the drawbacks of the above-mentioned prior art, and its purpose is to independently control the vertical motion component and the horizontal motion component of the looper of an overlock sewing machine. The goal is to configure the looper so that the locus of movement of the tip at the tip of the looper can be freely set, thereby changing the locus of movement between the reciprocating movement to capture the needle thread and the backward movement downward and to the left. By creating a closed looper curve that differs depending on the time, interference between the tip of the looper tip and the needle during the backward movement can be prevented.

In short, the present invention provides a looper drive device for an overlock sewing machine by attaching a looper to the tip of the needle.
a horizontal drive mechanism that reciprocates twice between reciprocating movements;
By configuring the horizontal drive mechanism by a vertical drive mechanism that makes one reciprocation during one reciprocation of the needle, and a drive coordination means that can arbitrarily set the drive coordination state of each drive mechanism, This achieves the preferred movement trajectory described above.

(Example) The present invention will be described below based on an example shown in the drawings. A machine frame 2 of a so-called compound sewing machine 1, which is an overlock stitch sewing machine according to the present invention, is, for example, a sewing machine equipped with a lockstitch stitch forming mechanism and an overedge stitch stitch forming mechanism, as shown in FIG. A pedestal 3, a pedestal 4 formed upright with respect to the pedestal, an upper arm 5 extending leftward from the pedestal, and a pedestal extending in the same direction directly below the upper arm. A free arm part 6 is a cylindrical sewing part for lockstitching extending from 4, and a free arm part 6 is a cylindrical sewing part for overlock stitching extending to the left from the lower end of the pillar part 4. The upper surface 7a of the free arm section is disposed below and in front of the upper surface 6a of the free arm section 6 for lockstitching.

A needle bar mechanism 10 for lockstitching is attached to the upper arm 5, and a needle bar mechanism 11 for overlock stitching is attached below the pillar section 4.

A needle thread adjuster 12, a looper thread thread adjuster 13, and a plurality of thread guide members 14 for oversewing are respectively attached to the pillar portion 4, and these members and the needle bar for oversewing are attached to the pillar portion 4. A cover plate 18 covering the mechanism 11 is
As shown in FIG. 2, it is pivotally attached to the lower right end of the pillar section 4. The lid plate 18 connects a locking piece 20 fixed to the lid plate with an elastic locking plate 21 fixed to the pillar portion 4.
The closed state is maintained by being locked to. Further, as shown in FIG. 1, a transparent plate 22 is fixed to the lower left end of the cover plate 18 so that the needle bar mechanism 11 for overlocking can be visually observed even when the cover plate is closed. At the lower end of the pedestal section 4, adjacent to the cover plate 18, a drawer plate 23 that can slide in the left-right direction is attached, as shown in FIG.

Next, the looper device 25 according to the present invention will be explained.

3 to 11, the main shaft 26 is supported by the frame portion 2a of the machine frame 2 with limited axial movement, and the first looper shaft 28 is perpendicular to the main shaft and supported by the frame portion 2a. Supported with limited axial movement. A bevel gear 31 having the same number of teeth and meshing orthogonally with a bevel gear 30 fixed to the main shaft 26 is fixed to one end of the first looper shaft. Therefore, the first looper shaft 28 is fixed to the main shaft 26 A rotational movement of 1:1 is performed. Further, a gear 32 is fixed to the other end of the first looper shaft 28.

As shown in FIG. 5, a second looper shaft 34 is located below the first looper shaft 28, and a third looper shaft 35 is supported to the left of the first looper shaft 28, with their axial movements being restricted by the frame portion 2a. has been done. Second looper shaft 34
A gear 36 that meshes with the gear 32 is fixed to the gear 32, and the diameter of the pitch circle of the gear is set to 1/2 of the diameter of the pitch circle of the gear 32. Therefore, the second looper shaft 34 rotates twice while the first looper shaft 28 rotates once.

Further, an eccentric cam 39 having an eccentric amount e is fixed to the first looper shaft 28, and the eccentric cam 39 has a first
The first link member 4 which is one half of the link mechanism 40 of
One end of 1 is inserted. Third looper shaft 35
Link members 42 and 43, which are the other halves of the first link mechanism 40, are fixedly attached to the respective members, and the other end of the first link member 41 is pivotally attached to one end of the link member 42.

The looper support 45 includes bearing parts 45a and 45b that slidably support the looper mounting shaft 46, and a guide shaft 47 that guides the slide in the axial direction of the looper support.
The guide shaft is slidably inserted into a hole 49a formed in a support support 49 which is pivotally connected with limited axial movement to a pivot 48 fixed to the frame portion 2a. ing. Further, as shown in FIG. 5, the other end of the link member 43 is pivotally attached to the bearing portion 45a on the left side of the looper support 45. As shown in FIG.

The looper 51 is fixed to the tip of the looper attachment shaft 46. One end of a second link member 52, which is one half of the second link mechanism 50, is fixed to the second looper shaft 34, and the other end of the second link member 52, which is one half of the second link mechanism 50, is fixed to the second looper shaft 34. One end of the third half link member 53 is pivotally connected. The other end of the third link member is connected to the bearing portion 4 of the looper support 45.
Looper mounting shaft 46 located between 5a and 45b
It is pivotally connected to a fixing member 54 fixed to. Further, in FIGS. 1 and 2, reference numeral 60 indicates a throat plate fixed to the upper surface of the free arm portion 7 for overlocking, and 61
6 is a needle fixed to the tip of an edge stitching needle bar 62;
3 is a throat plate fixed to the upper surface of the free arm portion 6 for lockstitching, and 65 is a cloth receiving plate.

The present invention is configured as described above, and its operation will be explained below. First, the looper device 25
I will explain about it. When the main shaft 26 rotates counterclockwise when viewed from the right side in FIG. 4, the bevel gear 30,
31, the first looper shaft 28 also rotates counterclockwise. Then, the second looper shaft 34 is connected to the gear 3
2, 36, and the looper mounting shaft 46 rotates through the second and third link members 52, 53, which are the second link mechanism 50, for one rotation of the first looper shaft 28, that is, the main shaft 26. Go back and forth twice to the left and right. Furthermore, the looper support body 45 is connected to the first link member 41 and the link member 42 which are the first link mechanism 40, and furthermore, through the third looper shaft 35 and the link member 43, for one rotation of the main shaft 26 about the pivot shaft 48. Performs one round of oscillating motion up and down.

The looper 51 is driven by the two combined movements of the vertical movement of the looper support 45 and the horizontal movement of the looper mounting shaft 46, and the rotation angle of the main shaft 26 is 0°, 90°,
For 180 DEG and 270 DEG, the looper device 25 is driven as shown in FIGS. 8, 9, 10 and 11, respectively.

In the figure, the Y-Y line is a needle drop line showing the locus of movement of the tip of the needle 61 in the direction of arrow M in FIG.

Further, the movement locus of the tip 51a of the looper 51 is as shown in FIG. In the same figure, Y-Y
is a needle drop line similar to that shown in FIG. 8 and the like.

As shown in FIG. 12, the tip 51 of the looper 51
The movement locus of a draws different closed looper curves during forward and backward movements, and when the tip 51a of the looper 51 moves toward the leftmost point P under the throat plate, the needle drop line Y
The point Q that intersects with -Y passes through a position deeper than the needle thread capture starting point R when viewed from the needle plate 60 surface. The motion locus of the needle 61 is at right angles in the direction of the arrow M in FIG. 4, as shown in FIG.
Since it is inclined with respect to the zero plane as shown in FIGS. 13 and 14, the tip 51a of the looper 51 is
At point Q in FIG. 2, the stitching thread passes through the needle 61 without interfering with it, as shown in FIG. 13, and at point R in FIG. A thread ring (not shown) is passed through in a manner capable of being captured.

The locus of the tip of the looper by the looper device conventionally used in this type of sewing machine is the Q of this embodiment.
Since the points corresponding to point and R point coincided, the first
As shown in FIG. 6, if the tip 51a of the looper 51 is made to be able to capture the yarn loop at a point corresponding to point R in this embodiment, then as shown in FIG. Now, the tip 51a of the looper 51 and the needle 6
1, there was a problem of interference, but this embodiment makes it possible to avoid this interference.

When performing overlock stitching, pull out the drawer plate 23 to the right and close the fabric receiving plate 6 as shown in FIG.
Expose 5.

In addition, each thread tension device 12 for needle thread and looper thread,
13 and the thread guide members 14 of each part, the cover plate 18 is opened as shown in FIG.

(Effects) Since the present invention is constructed and operates as described above, the vertical motion component and the horizontal motion component of the looper of the overlock sewing machine are taken from different motion sources, so that the tip of the looper can be moved easily. The movement trajectory can be set freely, and this allows the looper tip to have different closed looper curves during forward and backward movements, allowing the looper tip to reach the leftmost point under the throat plate. The tip of the looper and the needle do not interfere with each other when they move toward each other, preventing needle bending, needle breakage, thread breakage, etc., and has the effect of improving sewing performance.

[Brief explanation of the drawing]

The drawings relate to an embodiment of a compound sewing machine according to the present invention, and FIG. 1 is a perspective view of the compound sewing machine, and FIG. 2 is a perspective view of the compound sewing machine.
A perspective view showing a state in which the cover plate is opened and the drawer plate is opened to the right in the state shown in the figure, FIG. Figure 4 is a plan view of the looper device, Figure 5
The figure is a front view of the main parts of the looper device, Figures 6 and 7 are diagrams showing the operation of the looper device, and Figures 8 to 1
Figure 1 is a front view showing the position of the looper with respect to the rotational position of the main shaft, and Figure 8 is a front view showing the position of the looper with respect to the rotational position of the main shaft.
The figure shows a spindle rotation angle of 90°, Figure 10 shows a spindle rotation angle of 180°,
Fig. 11 is a front view showing the position of each looper when the spindle rotation angle is 270°, Fig. 12 is a movement trajectory diagram of the looper tip, and Figs. 13 and 14 are N of Fig. 3.
The relationship between the position of the tip of the looper and the needle in the direction of the arrow is shown. FIG. 13 is a longitudinal cross-sectional view when the tip of the looper passes through point Q in FIG. 12, and FIG. A vertical cross-sectional view when passing through point R in the figure,
15 and 16 show the positional relationship between the tip of the looper and the needle in the conventional example, and FIG.
FIG. 16 is a vertical cross-sectional view of what is shown in FIG. 14, and FIG. 17 is a trajectory diagram of the tip of the looper in the conventional example. 1 is a compound sewing machine that is an example of an overlock sewing machine;
2 is a machine frame, 2a is a frame portion, 25 is a looper device, 26 is a main shaft, 28 is a first looper shaft, 34 is a second looper shaft, 39 is an eccentric cam, 40 is a first link mechanism, 45 is a Looper support, 46, looper mounting shaft, 48, pivot, 49, support support, 50
51 is a looper, 60 is a needle plate for oversewing, and 61 is a needle for oversewing.

Claims (1)

[Claims] 1 The vertical movement and horizontal movement of the looper relative to the throat plate surface in the stitch forming mechanism of overlock stitching are extracted from separate movement sources, and the needle movement 1
A looper drive device for an overedge sewing machine, characterized in that, during reciprocation, the vertical movement is made one reciprocation and the horizontal movement is made two reciprocations.