JPS6318517B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a needle receiver for a sewing machine.

Conventional needle guards include fixed types, in which the needle receiver is fixed to the sewing machine bed, and movable types, which touch and release the needle as the feed table moves back and forth. When it comes to sewing products, this has the disadvantage of causing various sewing problems such as needle damage, needle breakage, skipped stitches, and thread breakage.
In the case of the latter type, which is fixed to the feed base, the above drawbacks are almost eliminated, but the position of the needle guard must be readjusted every time the amount of cloth feed is changed, making the operation complicated and troublesome. Not only this, but also the sewing work is interrupted, which has the disadvantage of reducing work efficiency.

In order to deal with these problems, a system was developed in which the needle receiver was not fixed to the feed base, but was moved toward and away from the needle by a mechanism installed separately from the feed mechanism. -5140.

However, even with such a needle guard device, in a sewing machine having two or three needles, when the looper captures the needle thread loop, the needle guard performs the needle guiding action on the rightmost needle in Fig. 1A. However, it was not possible to perform a needle guiding action on the central and leftmost needles. Therefore, the reality is that these needles still collide with the looper due to vibrations of the sewing machine and deflection of the needle during sewing, resulting in sewing problems such as needle breakage and skipped stitches.

This tendency has become a major problem as sewing machines become faster in recent years. The reason why the needle guiding action is not performed on the central or leftmost needle is as follows.

When forming the seam, as shown in Figure 1A (・
(The mark indicates the needle hole) The looper (the △ mark indicates its tip) moves to the left and sequentially captures the needle thread loop that is formed as the needle rises from the bottom dead center. , there is a timing lag in the capture of each needle thread loop, and therefore the needle rise amount until the thread loop capture is the largest for the leftmost needle. On the other hand, the needle receiver in the above device is oriented downward to the left as shown in the figure, and by the time the looper captures the center or leftmost needle thread loop, these needle tips have already left the needle receiver and ascended. It is. If the needle guard is pointing downward to the left and the needle guarding action is not performed for the center or leftmost needle when capturing the thread loop, move the needle guard upward to the left as shown in Figures 1B and C.
Alternatively, it is conceivable to make it horizontal, but in this case, even if the needle receiving function is performed, the following defects in seam formation will occur.

In other words, when the needle rises above the bottom dead center and a needle thread loop is formed above the needle hole, the needle guard gets in the way and prevents the proper loop from being formed, causing the needle to fall over and form a small loop, causing the thread loop to fall. This impedes capture and creates an obstacle to stitch formation. For this reason, in the existing needle receiver device, the needle receiver for stitch formation is placed in the first A.
As shown in the figure, it had to descend to the left.

Therefore, in order to eliminate the drawbacks of the above-mentioned needle receiver device, the applicant has made the needle receiver swing in the left and right directions in synchronization with the looper, thereby guiding the needle to any position without hindering stitch formation. We proposed a needle receiver device that can perform this action. One of them is the special request made in 1974.
−119594. However, the needle receiver in this device pushes each needle while rubbing it in a direction perpendicular to the feeding direction, which tends to cause the needles to sway horizontally, which tends to make the shape of the loop unstable and cause skipped stitches. . This tendency becomes more pronounced as the needle becomes thinner. Additionally, the swinging of the needle guard has the disadvantage of causing new vibrations in this type of sewing machine.

The present invention aims to provide a solution to these problems, and attempts to achieve this purpose by causing the needle guide to perform a needle guide action while raising the needle receiver in substantially the same direction as the needle. .

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, reference numeral 1 denotes a looper for forming stitches in cooperation with the needle, and as is known, the looper 1 can be moved left and right in the direction perpendicular to the feeding direction. It is designed to perform elliptical motion by a combination of motion and back-and-forth motion in the feeding direction.
In the illustrated apparatus, the horizontal movement of the looper 1 is effected by the swinging movement of the looper stand 3 caused by the reciprocating movement of the rod 2, and the back-and-forth movement is effected by the swinging movement of the looper stand 3 about the swing axis 4. A needle receiver 6 is provided behind the looper. This needle receiver 6 is the third to fifth needle receiver.
As shown in the figure, the mount 7 is fixedly supported by a mount 7, and the mount 7 has a bell-crank-shaped back-and-forth swing crank 8 rotatably supported by the swing shaft 4 at its intermediate portion. 81, is pivotally supported by a pin 9, and has one end pivotally supported on the sewing machine frame.
The swing arm 10 is connected to the other end of the swing arm 10 via a rod 11, and the swing arm 10 is pivotally attached at its intermediate portion to a rod 14 whose large diameter portion is fitted into an eccentric ring 13 fixed to the main shaft 12.

Therefore, the needle receiver 6 has a swinging motion in a vertical plane centering on the pin 9 and a back-and-forth swinging crank 8 due to the swinging motion of the swinging arm 10 using the main shaft 12 as a driving source.
The oscillation about the oscillation shaft 4 gives a oscillating motion in the front-back direction, and therefore the needle guard performs a longitudinal elliptical motion that is a combination of both of these movements.
When rising, it comes into contact with the needle rising from the bottom dead center and performs a needle guiding action (see Figures 6 and 7).

The vertical movement of the needle receiver can also be performed by linearly moving it in the vertical direction together with the mounting base, but as described above, it is better to move the needle receiver by swinging motion around the pin 9. It is desirable that the swing angle can be made smaller by increasing the diameter. The needle receiver 6 is also fixed to the mounting base at a predetermined angle α with respect to a line perpendicular to the feeding direction. This is because in a three-needle sewing machine as shown in the figure, when the needle guard 6 contacts the right-most needle N ₁ to perform a needle-guiding action, it contacts the middle or left-most needles N ₂ and N ₃ to form a loop. This is to ensure that it does not interfere with

Next, the needle guiding function of the needle receiving device of the present invention will be explained with reference to FIGS. 6 and 7.

FIG. 6 shows a state in which N ₁ , N ₂ , and N ₃ have risen slightly from the bottom dead center, and the looper 1 is about to capture the needle thread loop (not shown) formed on the rightmost needle N ₁ . At this time, the needle receiver contacts the needle N ₁ at the right end and performs a needle guiding action, but is separated from the intermediate and left end needles N ₂ and N ₃ as described above. Next, looper 1 draws a trajectory as shown in the diagram and moves the middle needle N ₂
Furthermore, when the leftmost needle _N3 is reached (Fig. 7), the needle guard 6 also follows the rising needle and moves upward from the dotted line position to the solid line position while drawing an arcuate trajectory protruding forward (toward the needle side). It is sequentially connected to needle N ₂ and needle N ₃ to perform needle guiding action. When the needle guard is performing a needle guiding action for the leftmost needle _N3 , the right end and middle needles _N1 and _N2 are guided forward by the needle guard because their tapered tips are located in the notch 61 of the needle guard 6. The amount of push and deflection towards will be reduced.

After the looper 1 captures the left end needle thread loop, the needle receiver moves back away from needle _N3 and then begins its downward stroke. When N ₁ , N ₂ , and N ₃ descend behind the looper, the needle receiver is retracted from the needle as described above, so there is no collision between them.

In the above embodiment, an example was shown in which the needle receiver device is applied to a three-needle sewing machine equipped with a looper (such sewing machines include a three-needle double chainstitch sewing machine and a flat stitch sewing machine). Of course, it is also possible to use it in a multi-needle sewing machine.

As described above, the needle catcher of the present invention is such that the needle catch moves along an elliptical trajectory in the vertical direction, so that no matter where the looper is trying to catch the needle thread loop, It reliably contacts the needle and performs a needle guiding action, and also moves away from the needle when unnecessary, and the formation of a needle thread loop on any needle is not obstructed by the needle receiver.

Also, compared to the needle guard device shown in Japanese Patent Application No. 119594/1983, the needle guard rises in approximately the same direction as the needle, and does not move horizontally against the needle while rubbing against it. Therefore, the loop shape is stabilized and skipped stitches do not occur. This advantage is more pronounced as the needle becomes thinner.

Furthermore, in the case where the elliptical movement of the needle guard is performed in the horizontal direction, the needle guard must move at least from the right needle to the left needle, and it is desirable that the trajectory of movement during that time be approximately linear. , the major axis of the elliptical trajectory becomes considerably large, resulting in a large amount of momentum and a large inertial force.In contrast, in the case where the elliptical movement of the needle guard is performed in the vertical direction, the section in which the needle guide action is performed is relatively narrow. Since the needle moves in an arcuate manner during that time, the major axis of the elliptical trajectory is shortened, so the amount of movement in the vertical direction is small, and the inertial force applied to the needle guard is also small, making it possible to operate at high speeds with little vibration.

Furthermore, if the needle receiver is moved up and down by vibration movement in a vertical plane, the swing angle can be reduced, and the amount of movement can be further reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the operation of a known needle receiving device;
The figure is a perspective view of the main parts of a sewing machine equipped with the needle receiver device of the present invention, FIG. 3 is a perspective view of the same needle receiver device, FIG. 4 is a front view thereof, FIG. 5 is a side view, and FIGS. 6 and 7 FIG. 2 is an explanatory diagram of the action of the needle receiver when the looper captures the needle thread loop. 1... Looper, 4... Swing axis, 6... Needle guard,
7...Mounting stand, 8...Front-back swing crank, 9...
Pin, 10... Swinging arm, 12... Main shaft, 14...
Rod.

Claims (1)

[Scope of Claims] 1. A needle receiver device for a sewing machine equipped with a needle receiver 6 that sequentially contacts each needle to guide a plurality of needles when the looper 1 captures a needle thread loop. The part that engages with the needle is formed to be inclined at a predetermined angle in the moving direction with respect to the locus of movement of the looper. 1. A needle receiver device for a sewing machine, characterized in that a mechanism for causing a separation movement is provided, and both mechanisms cause the needle receiver 6 to perform an elliptical movement in the vertical direction. 2. The sewing machine according to claim 1, wherein the mechanism for reciprocating the needle receiver along the longitudinal direction of the needle is a mechanism for swinging the needle receiver in a plane along the needle about a fixed axis. needle receiver device.