JPH01280496A - Needle guard device in double loop sewing machine - Google Patents

Abstract

PURPOSE:To prevent needle breakage or bending, and simultaneously, to eliminate a trouble to the loop formation of a needle thread by dividing a needle group into a plural number, face-providing a needle guard to each, fitting the needle guard to an individual vibrating shaft, respectively, vibrating the needle guard in a direction to approach or separate from the needle point in interlocking with the elevation of the needle, and simultaneously, abut- supporting it only when the needle is lifted from a lowering position. CONSTITUTION:A needle guard device 1 is equipped with a left needle guard 2 and a right needle guard 3 to face-provided to two sewing needle Aa and Ab, respectively, and with a driving mechanism 4 to drive respective needle guards. To a driving shaft 20 driven in synchronizing to the needles Aa and Ab and a looper B by a driving motor, one edge of linking rods 21 and 22 is fitted through an eccentric plate, and the other edge is fitted through linking fittings 23 and 24 to vibrating shafts 17 and 18. The linking rods 21 and 22 are reciprocated by the turn of the driving shaft 20, vibrating movements are given to the vibrating shafts 17 and 18, and the left and right needle guards 2 and 3 are vibrated in the direction to abut on or separate from the needle point when the needles Aa and Ab to be elevated are shifted to lifting movements from lowest edge positions. Thus, the needle thread fitted to the needle cannot trouble the formation of the loop to accompany the lift of the needle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a needle receiver device for a double chainstitch (flat U) sewing machine using a plurality of sewing needles.

[Conventional technology]

Figure 7 shows the procedure for the double chainstitch mentioned above. Figure 0 shows the stitch formation procedure for the three-thread double chainstitch using two needles. It is installed in the same way and can be raised and lowered at the same time. B is a looper to which the bobbin thread d is attached. In this double chainstitch movement, as shown in figures (a) and (b), the looper B
When the needle is pulled in the two directions indicated by the arrow, the left needle Aa, which is protruding downward first, descends while sliding against the back (back side) Ba of the looper B, and enters the space between the looper B and the bobbin thread d that is let out from the tip of the looper. Insert into. Therefore, when the needle Aa reaches the lowest point, it bends or swings as shown by the chain line Ac in FIG.

Similarly, when the looper B moves back further and the needle Ab descends, the needle Ab also slides down the back Ba of the looper, causing bending or wobbling. Both needles Aa and Ab return to their original positions by self-elasticity, and then 6 needles Aa.

Ab rises, and as a result, upper thread a is placed behind the 6th stitch.

A loop C of b is formed, and the looper B moves forward and is inserted into this loop C ((C) in the same figure).

However, when the rotation speed increases and a needle with a fine count is used, an impact that penetrates the fabric is also applied, and louver B is inserted before the needle recovers due to elasticity, so louver B collides with the needle and breaks. Or skipped stitches occur.

In order to prevent this, a needle guard 50 is provided as shown in FIG. 8(a), and is moved to the front 01 in conjunction with the forward and backward movement of the louver B. When the hands Aa and Ab are lowered, it is retracted backward and the looper is moved forward. At the same time (in the direction opposite to arrow Z), means are being sought to move forward and push out the bent needle and hold the needle tip in a predetermined straight position.

[Problem to be solved by the invention]

In this case, the left and right needles Aa and Ab are attached with a step above and below as shown in the figure, and the tip of the needle Ab is attached to the needle guard 50.
In order to be supported by the needle guard 50, the right needle Aa descends considerably below the needle guard 50, which may cause the needle thread a to be caught in the needle guard 50. Therefore, when the right needle Aa rises, the upper thread a becomes twisted (see (b) in the same figure), and a loop is not formed, resulting in problems such as mistakes in insertion of the louver B and skipped stitches.

SUMMARY OF THE INVENTION In consideration of these points, it is an object of the present invention to provide a needle guard device that prevents needle breakage or bending and does not impede loop formation of the needle thread.

[Means to solve the problem]

To achieve the above object, the needle receiver device of the present invention is used in a double chainstitch sewing machine equipped with a plurality of needles and a louver for attaching a bobbin thread. and the needle supports are each mounted on a separate pivot shaft,
It is swung toward and away from the needle in conjunction with the rise and fall of the needle, and is supported in contact with the needle tip only when the needle rises from the lowered position.

In this case, one rocking shaft is fitted into the other cylindrical rocking shaft, and each rocking shaft can be rocked via a connecting rod attached to a drive shaft rotated by a drive motor. preferable.

[Effect]

Each needle guard abuts the tip of the needle when the opposing needle rises and presses and supports it in a normal position, thereby preventing the advancing louver from coming into contact with the needle. Furthermore, by dividing the needle guard, the contact position can be limited to only the tips of the opposing needles, and the needle thread will not be pinched.

Also, by inserting one swing shaft into the other swing shaft, it can be used in narrow spaces! Convenient for two positions.

〔Example〕

1 to 4I2I show a first embodiment of the present invention.

The figure shows the present invention applied to a three-thread double chainstitch sewing machine M with two needles Aa, Ab and a bobbin thread looper B. Right hand, Ab
A left needle guard 2, a right needle guard 3, and a drive mechanism 4 for driving the respective needle guards are provided. The left and right needle receivers 2.degree. 3 each extend from the mounting base 5.6 and are provided with an abutment portion 7.8, which forms a needle tip bearing surface 9.degree. 10 with an inclined upper surface.

The drive mechanism 4 includes a mounting arm 1 that supports the mounting base 5.6.
5.16 is attached to the tip, one of the swing shafts 18 is hollow and rotatably supported by a bearing 19, and the other swing shaft 17 is mounted inside the swing shaft 18. Insert it and support it so that it can rotate freely.

20 is a drive shaft driven by a drive motor (not shown) in synchronization with needles Aa, Ab and louver B. One end of connecting rod 21.22 is attached via an eccentric plate, and the bottom end is connected to connecting metal fittings 23.24. It is attached to the swing shafts 17 and 18 via. Then, as the drive shaft 20 rotates, the connecting rod 21.
22 performs a reciprocating motion, giving a rocking motion to the rocking shafts 17 and 18, and the left and right needle receivers 2 and 3 come into contact with the tips of the ascending and descending needles Aa and Ab when they move from the lowest position to the upward movement. Or swing in the direction of separation.

However, the needles Aa and Ab are installed with a step in the vertical direction as described above, and therefore, the abutting parts 7 and 8 of the needle guard 2.3 are installed with a step in the top and bottom as shown in FIG. It is being

However, as shown in Fig. 3(b), the insertion position of louver B is the same for both needles Aa and Ab, and the insertion of louver B is made when needle Ab has a slight rise and forms a loop in the upper thread. is possible, and therefore, the abutment part 8 of the right needle guard should be located opposite to the needle tip of the needle Ab, but the abutment part 7 of the needle guard 2 for the other left turn Aa should be positioned opposite to the needle tip of the louver B when it is inserted. In order to support it, it is located slightly above the needle tip and is opposed to it, so it is located across the upper thread a, and as can be seen from the figure, the front and rear swing distance is the same as the contact part of the other needle guard 3. It is greater than 8.

Next, based on the double chainstitch process diagram shown in Fig. 4, the needle guards 2 and 3 are
Explain how it works.

Figure (a) shows the needles Aa and Ab penetrating the fabric; first, the left-turning Aa descends while brushing against the back (back 011) Ba of the louver B. Then, as shown in FIG. 5(b), the needle Ab descends in the direction of the arrow Z while sliding against the back Ba of the louver B which is moving. In addition, in the left turn Aa, as the needle comes into contact with the louver B, the tip of the needle is in a state slightly more focused than the normal position shown by the chain line, as shown in FIG. Figure (C) shows a state in which the louver B has been pulled out from the needle Ab, and the needle Ab is also in a state slightly away from the normal chain line position. From this point on, the needle guards 2 and 3 begin to move from the retracted position in a direction toward the needle.

The figure (d) shows the point in time when the hands Aa and Ab rise from the lowest point, and the louver B starts moving in the left direction 2a. At this point, the abutment surface 10 of the right needle guard 3 is first moved to the needle tip as the needle Ab rises, and the abutment surface lO is and start correction.

FIG. 5(e) shows a state in which the needles Aa and Ab are raised and the upper thread forms a loop C, and the bending of needle Ab is corrected by the needle guard 3 and maintained in a normal state. Thereby, the tip of the louver B can be inserted into the loop C without colliding with the needle Ab.

Note that the support surface 9 of the needle guard 2 for the other needle Aa is located at a position opposite to the needle Aa with the upper thread a interposed therebetween.

In the same figure (f), the needles Aa and Ab further rise, and the needle Ab with needle moves away from the needle guard 3 and when Aa turns left, the bearing surface 9 of the needle guard 2 comes into contact with the needle tip, corrects the bending, and maintains the normal state. Indicates the state of
As a result, the louver B can be reliably inserted into the loop C formed by the needle thread a, similar to the case with the needle Ab described above.

FIG. 5 shows a second embodiment. In this example, three sewing needles Aa
, Ab, Ac, and a louver B similar to the previous example. The needle receiver w130 of this embodiment includes two needle receivers 31 and 32, one needle receiver 31 facing the needles Aa and Ab, and the other needle guard 32 facing the needle Ac.

Note that the drive mechanism for the needle receivers 31 and 32 has the same structure as the previous example, and the explanation thereof will be omitted.

However, when the left needle guard 31 moves forward, it first comes into contact with the tip of the middle needle Ab, and at that time, it is in a slightly backward position with respect to the left turn Aa, and the left needle guard 31 with the middle needle Ab raised above the needle guard further It is preferable to move forward and come into contact with the needle tip of the left turn Aa. For this reason, as one means, the bearing surface 33a may be a stepped surface that is slightly recessed from the bearing surface 33b for the center needle Ab toward the left turn 1a, or it may be an inclined surface whose left end is retracted to obtain the same effect.

The manner in which the needle tip is supported by the needle supports 31 and 32 is the same as in the previous example, and the explanation thereof will be omitted.

FIG. 6 shows a third embodiment. This example uses four sewing needles Aa.
, Ab, Ac, Ad and a louver B similar to that of the first embodiment. The needle guard device 40 of this embodiment includes two needle guards 41 and 42 as in the previous example, one needle guard 41 facing the needles Aa and Ab, and the other needle guard 42 facing the needles Ac and Ad. It will be deployed. The drive mechanism for the needle receivers 41 and 42 has the same structure as in the first embodiment, and the explanation thereof will be omitted.

It is preferable that the respective bearing surfaces 43, 44 of the needle holder 41, 42 have a step, similar to the bearing surfaces 33a, 33b of the needle holder 31 in the previous example, so that they abut the opposing needle tips with a time difference.

The manner in which the needle tip is supported by the needle supports 41 and 42 is similar to the previous example, and the explanation thereof will be omitted.

Note that the second and third embodiments above show an example in which three or four needles are divided into two groups, each of which is provided with a needle guard, and each needle guard is moved forward and backward separately in conjunction with the rise and fall of the needles. However, the needle holder is divided into sections for each sewing needle, that is, 3 needles are used for the 3 needles shown in the second embodiment (by the needle holder Il, and 4 needles are used for the 4 needles shown in the 3rd example am). It is also possible to provide a needle guard so that the opposing needles are slightly raised from the lowest position as shown in the first embodiment; when the looper passes through the soffit, the needle tip is pressed and supported in the normal position.

〔Effect of the invention〕

According to the present invention, the sewing needle is divided into a plurality of parts, each of which is provided with a needle guard facing each other, moved forward one step backward in conjunction with the vertical movement of the opposing needles, and moved forward when the needle rises from the lower position. Since the needle tip is supported, there is no risk that the upper thread attached to the needle will be supported in the formation of a loop as the needle rises.

In addition, when the looper passes through one side and is inserted into the loop, the needle guard presses and holds the needle tip in the correct position, so there is no risk of the advancing looper coming into contact with the needle.
Therefore, the needle does not break or bend due to contact, and the looper is reliably inserted into the loop formed by the upper thread, so there is no risk of skipped stitches.

In addition, when inserting one swing shaft into the other part's swing shaft, the swing shaft that swings each needle guard in the front-rear direction must be placed in a narrow slot (convenient for installation in a location = j). It has the effect of

[Brief explanation of the drawing]

1 to 4 relate to the first embodiment, FIG. 1 is a perspective view of the entire needle receiver, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is an explanatory diagram of the relationship between the needle receiver and the needle. Figure (a) shows the needle in the downward position, Figure (b) shows the front view when the looper is moving forward, and
The figure is a double chainstitch process diagram, FIG. 5 is a second embodiment, and FIG. 6 is a third embodiment, and is an explanatory diagram of the relationship between the needle guard and the needle, respectively.
Figure 7 is an explanatory diagram of the relationship between the double chainstitch needle and the looper, and Figure 8
The figure is an explanatory diagram of the operation of a conventional needle guard. 1, 30.40 is the needle receiver, 2, 3, 31, 32
, 41.42 is the underwriting, 17.18 is the swing axis, Aa, Ab
, Ac, and Ad are needles, B is a looper, and M is a double chainstitch sewing machine. 1 other person-a! Figure 3 Figure 5 Figure 6 Figure 4

Claims (2)

[Claims] (1) In a double chainstitch sewing machine equipped with a plurality of needles and a looper for attaching a bobbin thread, the needle group is divided into a plurality of groups, each of which is provided with an opposing needle guard, and each needle guard has a separate rocker. A double chainstitch that is attached to a moving shaft, swings toward and away from the needle in conjunction with the rise and fall of the needle, and is supported in contact with the needle tip only when the needle rises from the lowered position. A needle guard device in a sewing machine. (2) One swing shaft is inserted into the other cylindrical swing shaft,
2. The needle receiver device for a double chainstitch sewing machine according to claim 1, wherein each swing shaft swings via a connecting rod attached to a drive shaft rotated by a drive motor.