JP2002360961A - Method for forming end knot of single yarn stitching seam and single yarn stitch sewing machine for implementing the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure stability of an end knot and to minimize the technological cost of a single yarn stitch sewing machine suitable for implementing a method of forming an end knot of a single yarn stitching seam, and device for forming the end knot of the single yarn stitching seam. SOLUTION: The end knot forming device has a hold back finger 5. The hold back finger 5 is capable of moving into a yarn loop A of a first step still caught in a looper 1 and a second yarn loop B of the next stitch hold by the looper 1 and further drawn out by the looper 1 when a needle 2 is located substantially in a yarn loop lifting position after a seam is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-thread chain stitch using a chain stitch machine having a needle for guiding a thread, a rotary looper cooperating with the needle, and possibly an auxiliary looper. FIELD OF THE INVENTION The present invention relates to a method for forming an end knot and a single thread stitch sewing machine for performing the method.

[0002]

2. Description of the Related Art In the case of a stitch caused by a single thread ring stitch sewing machine, the upper thread loop of the previous stitch is expanded, so that the needle passes through the thread loop of the previous stitch during the next stitch. Can be done. As a result, the next thread loop holds the thread loop of the previous stitch. However, since the thread loop allows the next thread loop to pass through with little hindrance, the single thread ring stitch can be unwound relatively easily in the direction opposite to the stitch forming direction.

[0003] Therefore, it is known to fix the end of a single thread ring stitch, in particular to fix the thread loop of the last stitch so that it is not unraveled by a knot. In the method described in DE 196 41 638 A1 or in a sewing machine used to carry out this method, a knot consisting of a plurality of thread loops is formed. In this case, first, the first loop formed by the stitch two steps before the last stitch is increased by a certain amount compared to the loop length required during the original stitch forming step, That is, it is further drawn out by a certain amount. Next, the first loop thus lengthened is inserted into the second loop formed by the stitch immediately before the last stitch, thereby forming the last stitch. During the knot, a knot occurs and the first thread is held by the second thread. Since the lengthened first thread loop is inserted into the second thread loop after the formation of the second thread loop, the first thread loop is formed after the knot is formed by the knot formed by the second thread loop. Fixed by part. As a result, the free end of the first thread loop caused by thread trimming is always retained by the first thread loop after exiting from both thread loops, so that the knot thus formed is connected to the said German Federal Republic. It cannot be unraveled as described in JP-A-19641638A1 at column 9, line 68 et seq.

In this way, the sufficient stability of the knot provided is achieved, but this is achieved by pulling out the two stitches before the last stitch relatively long with an auxiliary thread puller. The yarn must be pulled so as to penetrate the yarn, and the yarn drawn out in such a long time is used while the second yarn is formed and the third yarn is formed. Since it must be controlled to be retained, it is relatively difficult, especially in terms of its length, so that the construction of the chain stitch machine is necessarily complicated.

In connection with the formation of single thread ring stitches, German Patent Publication No. 1168228 discloses
A method of winding the previous yarn loop around the next yarn loop has become known. In this case, the stitch forming yarn loop of the previous stitch is first pulled out in the advance direction of the seam to be formed, and thereafter the stitch forming thread is moved about one axis around the substantially horizontal axis.
It is turned by 80 °, which results in some kind of double loop with crossing of the loop legs in one plane. Thereafter, the double thread loop thus formed is rotated from the intersection of the legs in the direction of the previous puncture, so that the thread loop originally in front of the double thread loop is below the other thread loop. In this case, the needle penetrates both thread loops of the double thread loop when the needle is punctured, and pushes the two thread loops apart. This method can be applied to form a continuous stitch during the formation of each stitch, and can also be applied to form an end knot, but in this method,
In order to form a double loop, the front area of the loop must be rotated by 180 DEG and the front loop formed in this way must be positioned below the rear loop produced at that time. The technical cost of a single thread stitch machine suitable for carrying out this method is relatively high.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for forming an end knot of a single thread ring stitch.
The aim is to provide a method which guarantees sufficient stability of the end knots, while minimizing the technical costs of a single thread stitch machine suitable for performing this method.

It is a further object of the present invention to provide a single-thread chain stitch sewing machine suitable for carrying out the method, which has a simple structure.

[0008]

According to the present invention, there is provided a method for solving the above-mentioned problems, comprising: a) the loop B held by the tip of the looper is still held by the looper during the previous stitch; Inserting the loopback A extending from the stitch toward the looper into the loop A, and b) inserting the holdback finger, which is oriented substantially in the horizontal direction, into the loop A, B still gripped by the looper. Winding both thread wheels A and B around the holdback finger; and c) moving the holdback finger from its lower motion trajectory to a raised position, preferably in the area near the lower surface of the needle plate, A
D) the loop C formed at the next puncture of the needle is gripped by the tip of the looper, and the twist or rotation of the loop B caused by winding the loop B around the looper is completed. When the thread wheel B has not yet fallen from the looper, the thread wheel C is inserted through the thread wheel B. e) The holdback fingers are returned from the thread wheels A and B, and the thread wheel B is Retracting, and f) cutting the intermediate portion of the yarn C extending from the entanglement of the yarns A and B toward the looper in the region of the entanglement of the yarns A and B. It is a feature.

[0009] In the single thread chain stitch sewing machine for performing the above method, the end knot forming device has a holdback finger, and the holdback finger is
After the seam is formed, when the needle is approximately in the loop lift position, the loop of the first stitch still hanging on the looper and the second of the next stitch gripped by the looper and further pulled out by the looper. It is characterized by being movable into and out of the yarn loop.

[0010] The technical idea underlying the method according to the invention is that the thread A formed by two stitches before the last stitch is formed by the thread B formed by one stitch before the last stitch. If, by means of the free end remaining on the sewing product after thread trimming, it is fixed twice, ie if this thread end is wound twice by the thread wheel A formed by the two stitches before the last stitch, The two knot stitches formed before the last stitch originate in obtaining a sufficiently stable end knot.

According to the present invention, even in a chain stitch machine having a rotating looper, the upper thread wheel received by the looper tip is used to wind the remaining free end of the sewing product twice in this manner. Takes advantage of the fact that it rotates 180 ° about an axis approximately parallel to the needle while winding it around the looper. Such rotation of the thread loop (sliding down from the looper and then returning to its home position) cooperates with the thread loop C inserted by the looper into the thread loop B before the thread loop B slides down from the looper. Before the yarn B is wound around the looper, the yarn is stopped by the holdback finger penetrating into the yarn B.

The holdback finger moves from the rear reversing position on the motion trajectory into both the yarn loops. The movement trajectory intersects the movement of the needle in the region of the needle wheel lifting position and somewhat above the needle hole, so that the holdback finger penetrates the yarn A still hanging on the looper and , Penetrate into the thread loop B formed by the needle.

The thread A is tightened on the holdback finger. To prevent the thread A from being too long by pulling the thread A upward as much as possible, the tip of the holdback finger is moved from its lower movement trajectory to the needle. It can be lifted to the upper motion trajectory in the area near the plate, and can return to the area of the rear reverse position along this upper motion trajectory, and descend to the height of the lower motion path in the area of the rear reverse position. Can be. Important in this context is that when the needle is at the height of the thread lift position, the holdback finger will
And B, and escapes from these thread loops again as close as possible to the lower surface of the needle plate.

A holdback finger provided on a single thread ring stitch sewing machine suitable for carrying out the above-described method is provided when the needle is substantially in a raised position after the seam is formed.
It is movable into the thread loop of the first stitch still hanging on the looper and into the second thread loop B of the next stitch which is further pulled out by the looper gripped by the looper. is there. Thus, both thread loops A and B can be gripped by the holdback finger by one movement of the holdback finger.

In order to extend the thread loop slightly longer than the extension of the thread loop A when forming a seam, the holdback finger can be inserted into both the thread loops A and B along the lower movement trajectory, It can be lifted from the lower motion trajectory to a position inside the upper motion trajectory, which is located in the vicinity of the needle plate.

In this case, since the needle plate has a cutout on the lower surface thereof and the holdback finger is movable into the cutout, the length of the thread wheel A can be further reduced. .

The movement of the holdback finger from the rear reversal position to the shell front reversal position, and the subsequent movement from the lower movement trajectory to the upper movement trajectory, is performed by a single movement of the drive means. As a result, the holdback finger is received by a swinging lever which is movable relative to the carrier, the carrier is fixedly connected to the driving means (oscillation shaft), and the holdback finger has its lower movement In the region of the front reversal position of the track, it is possible to lift up to the upper movement track by the relative movement between the swinging lever and the support which are derived by the movement of the support.

In terms of structure, in order to easily derive the relative motion of the swing lever with respect to the carrier, a double lever is supported by the carrier, and one end of the double lever is
When the holdback finger is in the region of the front reversing position of its motion trajectory, it comes into contact with the stopper, and the other end of the double lever is driven by the swing lever via an intermediate member (lever) supported by the swing shaft. Are combined.

A rotary spring is fixed to the carrier to fix the relative position between the swing lever and the carrier while the holdback finger is moving along the lower or upper motion trajectory. One leg is supported by a swing lever, and the other leg is supported by a carrier.

In the case where the relative movement between the swinging lever for guiding the holdback finger from the lower movement track to the upper movement track and the carrier is performed against the pretension of the rotary spring,
Since the rotary spring partially relaxes again as the holdback finger moves from its upper motion trajectory to the lower motion trajectory, no special drive is required to carry out this motion, and the holdback finger is In order to return from the position where the yarn loops A and B are held to the rear reverse position provided on the lower movement track, the swing shaft only needs to be moved once.

Other advantages and details of the method according to the invention and of the single thread stitch machine constructed according to the invention are evident from the following description of an embodiment of the invention illustrated in the drawings.

[0022]

DETAILED DESCRIPTION OF THE INVENTION In the following, a method according to the invention and
A chain stitch sewing machine for performing this method will be described.

FIG. 1 shows the state of the yarn loop at the start of forming the end knot. At this point, the thread wheel A formed by the previous stitch is still on the looper.
The thread loop A extends from the sewn product to the looper through the auxiliary looper in the reverse position. The needle is in the loop lifting position and then moves upward to leave the loop lifting position. The next thread B has already been formed, and the point of the looper has penetrated into this thread B. When the holdback finger has moved from its rear reversal position toward the needle, its point has not penetrated neither thread A nor thread B. However, the tip of the holdback finger is immediately before the thread wheel B. As the looper rotates further, the thread loop A hanging on the looper moves toward the pointed end on the back of the looper, but just before falling from the back of the looper. In this case, the thread wheel B is further pulled out from the tip of the looper. The holdback finger moves along its lower motion trajectory, and the further pulled out thread B
And the thread wheel A (FIG. 2).

When the loop A falls from the looper and the looper further pulls out the loop B, the loop A is pulled upward by a balance as usual. At the same time, the holdback finger is lifted from its lower trajectory to the height of its upper trajectory and is located just below the throat plate. As a result, the yarn A is tightened on the holdback finger so that the yarn A does not become too long, so that the holdback finger can later escape from the yarn A again. While the loop A is being pulled upward, the looper rotates further, and the loop B is further expanded. In this case, the thread wheel B has not been twisted (or rotated) yet (FIG. 3).

Even if the looper is further rotated, the position and length of the thread wheel A do not change. Therefore, the length is smaller than the length in the normal sewing process by an amount generated by winding the holdback finger. It's only long. The holdback finger is still in the position shown in FIG. After reaching the bottom dead center position, the intermediate needle again moves to the thread wheel lifting position and continues the upward movement. While the loop B is still tensioned on the looper and extends from there through the auxiliary looper to the holdback finger, its point grips the next loop C and wraps it around the looper Start (Figure 4).

During this time, the thread wheel B is wound around the rotating looper, so that the thread wheel B has a needle like the case where the lockstitch rotary hook is rotating and the case where the chain stitching looper is rotating. 180 ° about an axis extending substantially parallel to. The pointed end of the looper allows the thread wheel C to be inserted into the thread wheel B before the thread wheel B thus rotated falls from the looper, and then the thread wheel C falls from the looper and is pulled upward. The torsion (or rotation) of the loop B caused by winding the loop B around the looper is formed again because the loop C is inserted through the loop B before the loop B separates from the looper. Therefore, the thread wheel B has a kind of double wheel shape.

While the thread wheel B is being pulled upward, the thread wheel C
Is guided further around the looper and tense through its back. This situation is shown in FIG. FIG.
FIG. 7 shows an extension state of the yarn loop before the start of tightening of the yarn loop B, and a situation in which a part of the yarn loop C still on the looper is pulled out. At this time, the holdback finger returns to the rear reverse position along its upper motion trajectory,
It is then lowered to the level of its lower trajectory to reach the home position for forming the next end knot. At the same time, the holder back finger returns to its rear reverse position (FIG. 5).

FIG. 6 shows the manner in which the yarn loops A, B, and C extend immediately before the tightening of the yarn loop B is completed. The yarn loop C guided through the looper is still in a tension state. As can be seen from FIG. 6, the thread loop A is almost in a tightened state, with its legs extending towards the sewing product or the button to be sewn. The thread wheel B is also almost in a tightened state, and both the leg B1 extending toward the thread wheel A and the leg B2 extending toward the thread wheel C pass through the thread wheel A. The leg C1 of the thread wheel C, still guided through the looper, reaches the leg B2 of the thread wheel B, while the leg C2 reaches the needle via the sewing material.

The extending mode of the yarn loops A, B, and C shown in FIG. 6 substantially corresponds to the yarn extending mode when the yarn loop C is cut. Since the thread trimming takes place in a known manner in the region of the leg C1 of the yarn loop C, the yarn end remaining in the knot thus formed is relatively short and reaches the yarn storage. The free end of the thread is relatively long (FIG. 7).

The single thread chain stitch machine schematically shown in FIG. 8 has a needle 2 which cooperates with a rotating looper 1 in a known manner. Both the needle 2 and the looper 1 are driven in a known manner by an upper shaft (not shown). If the single thread ring stitch sewing machine illustrated in connection with the embodiment is a button stitch sewing machine that does not carry the sewing material in the usual manner, an auxiliary that cooperates with the looper 1 in the usual manner to hold the thread loop. A looper 3 is also provided. The auxiliary looper 3 is arranged in a known manner on a swing shaft 4 driven to be displaceable also in the axial direction. The auxiliary looper 3 is necessary for forming a stitch in the case of a button-stitched sewing machine, but has no functional role in forming an end knot of a single thread ring stitch. It just explained.

The device for forming the end knot has a holdback finger 5 which is shown in detail in FIGS. The holdback finger 5 is driven by a swing shaft 6. Therefore, the crank 7 is provided on the swing shaft 6.
Has been fixed. The crank 7 is connected to a double-acting pneumatic cylinder 8 via a pivot connection (not shown). The pneumatic cylinder 8 can be controlled by a main control unit of the sewing machine.

The movement of the swing shaft 6 moves the holdback finger 5 along its lower motion trajectory from the rear reverse position to the front reverse position for gripping the yarn loop, and along the upper motion trajectory. Used to return from the reverse position to the rear reverse position. Further, the motion of the swing shaft 6 causes the movement of the holdback finger 5 from the lower motion trajectory to the upper motion trajectory performed in the region of the front reversal position, and from the upper motion trajectory to the lower motion trajectory performed in the region of the rear reversal position. Is also derived.

In FIG. 8, a carrier 9 fixedly connected to the swing shaft 6 is disposed at the left end of the swing shaft 6. A pin 11 is supported on the carrier 9. The pin 11 is for supporting the swing lever 12, and the holdback finger 5 is fixed to the swing lever 12. A pin 13 is further fixed to the carrier 9, and a double lever 14 is rotatably supported on the pin 13, and its upper end 15 cooperates with a stopper 16 fixed to the housing formed by a screw. The lower end 17 of the double lever 14 carries a pin-shaped driver 18. The entrainer 18 protrudes into the slit 19 of the lever 21. The lever 21 is loosely supported on the swing shaft 6. The lever 21 has the second slit 2
2 are provided, and a pin 23 is engaged with the second slit 22. The pin 23 is supported by the swing lever 12 and projects laterally with respect to the swing lever 12. Pin 2
The leg 3 of the rotary spring 25 supported by a screw 26 fixed to the carrier 9 is in contact with 3. The other leg 27 of the rotary spring 25 is in contact with a pin 28 fixed to the carrier 9. To allow the position of the holdback finger 5 to be adjusted, the pin 23 of the swing lever 12 that supports the holdback finger 5 and protrudes into the slit 22 of the lever 21 is positioned at the rear reverse position of the holdback finger 5. Abuts against a position-adjustable stopper 29 formed by a screw screwed into the carrier.

In order to displace the holdback finger 5 from the rear reverse position shown in FIG. 9 to the position where the yarn loops A and B are gripped, the holdback finger 5 is moved along its lower movement trajectory. Therefore, the carrier 9 is swung by the swing shaft 6. The double lever 14 disposed on the pin 13 and the double lever 1 via the driver 18
The lever 21 which is connected to 4 participates in this swinging movement without performing a relative movement with each other. The holdback finger 5 is inserted into the yarn loops A and B.

When the upper end 15 of the double lever 14 reaches the stopper 16 and comes into contact therewith, the double lever 14 rotates around the pin 13 fixed to the carrier 9,
In this case, the lower end 17 is pin 13 in the clockwise direction in FIG.
Rotate around. As a result, the lever 21 rotates around the swing shaft 6 in the counterclockwise direction since the entrainer 18 projects into the slit 19.

While the lever 21 is rotating counterclockwise, the swinging lever 12 is entrained by a pin 23 projecting into a slit 22 of the lever 21. In FIG. 9 and FIG. Rotate around.
In this case, the rotary spring 25 is further tightened via its leg 24 which abuts on the pin 23, and at the same time the holding back finger 5 is lifted from its lower movement track to the upper movement track, so that the carrier 9 is also held. The back finger 5 also reaches the end position of the movement for gripping the yarn loop. As can be seen from FIGS. 9 and 10, in this case the holdback finger 5 is raised until it protrudes into the cutout 32 provided on the underside of the needle plate 31, whereby the thread wheel A is formed in the usual stitch formation. Just slightly longer than The holdback finger 5 is also held on the upper motion trajectory by the thread wheel A after the thread wheel A is tightened on the holdback finger.

After the last loop C has been received by the looper tip, a return movement of the holdback finger 5 to the rear reverse position along the upper movement trajectory can be introduced. Therefore, the pneumatic cylinder 8 is controlled via the main control unit of the sewing machine, and the crank 7 is returned to its home position. With this, the holdback finger 5
First moves along its upper motion trajectory in the direction of the rear motion trajectory. In this case, since the holdback finger 5 is initially still inside the two yarns A and B, the holdback finger 5 is held in the upper position by the two yarns. When the holdback finger 5 comes out of both the thread wheels A and B, the rotation spring 25 is relaxed at this point, and the holdback finger 5 rotates around the pin 11 and returns to the lower motion trajectory.

[Brief description of the drawings]

FIG. 1 is a view for explaining the situation of thread loops A and B at the start of forming an end knot.

FIG. 2 shows a thread wheel A with a holdback finger in a lower position.
FIG. 6 is a diagram for explaining the situation of thread loops A and B when they are intruding into the loops A and B.

FIG. 3 shows a thread wheel A with the holdback finger in the upper position.
FIG. 5 is a diagram showing the yarn wheel A being pulled upward when the yarn wheel B has entered the inside and the yarn wheel B is partially pulled out.

FIG. 4 is a view for explaining a situation of thread loops A and B immediately before another loop C is gripped by a looper.

FIG. 5 shows the situation of the yarn loops A and B after the yarn loop B has dropped from the looper, the yarn loop C has been partially pulled out, and the holdback finger has partially returned. FIG.

FIG. 6 is a view showing the states of the yarn loops A and B which are almost tightened, and the yarn loop C further pulled out.

FIG. 7 is a diagram showing an end knot after thread trimming.

FIG. 8 is a front view showing the schematic view of the chain stitch sewing machine in a partial cross section.

FIG. 9 is an end view of the end knot forming device when the holdback finger is in the rear inverted position region.

FIG. 10 is an end view of the end knot forming device when the holdback finger is in its front inverted position region.

11 is an enlarged sectional view of FIG. 1 in the region of the end knot forming device.

FIG. 12 is a plan view of a region of the sewing machine illustrated in FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Looper 2 needle 5 Holdback finger 6 Oscillating shaft 9 Carrier 12 Oscillating lever 14 Double lever 16 Stopper 21 Lever 25 Rotating spring 31 Needle plate 32 Pullout part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3B150 AA04 CB14 CD07 CE01 CE27 DF04 DF08 FA00 FH02 FH11

Claims (8)

[Claims] An end knot for a single threaded chain stitch is formed using a chain stitch machine having a thread guiding needle, a rotating looper cooperating with the needle, and possibly an auxiliary looper. A) passing the loop B gripped by the tip of the looper through the loop A still gripped by the looper during the previous stitch and extending from the stitch to the looper; b) substantially The holdback finger pointing in the horizontal direction is moved to the thread A, still held by the looper.
B) and winding both thread loops A, B around the holdback finger; c) moving the holdback finger from its lower motion trajectory to a raised position, preferably in the area near the lower surface of the needle plate Moving and retracting the thread A, and d) the thread C formed at the next puncture of the needle is gripped by the looper tip, and the thread B is formed by winding the thread B around the looper. At the point where the twist or rotation of B has been completed but the thread wheel B has not yet fallen from the looper, a step of inserting the thread wheel C through the thread wheel B; and e) moving the holdback finger from the thread wheels A and B. F) retracting the yarn B, and f) moving the intermediate portion of the yarn C extending from the entangled portion of the yarns A and B toward the looper in the region of the entangled portion of the yarn A and B. Severing in the method. 2. A simple device comprising a needle for guiding a thread, a rotary looper cooperating with the needle, an auxiliary looper, and an end knot forming device for forming an end knot of a seam to be formed. In the thread stitch sewing machine, the end knot forming device has a hold-back finger (5), and the hold-back finger (5) moves the looper after the stitch is formed when the needle (2) is almost in the thread wheel lifting position. 1st stitch thread loop (A) still hanging on (1)
And the second stitch of the next stitch that is gripped by the looper (1) and further pulled out by the looper (1)
A single thread ring stitch sewing machine which is movable into and out of the thread loop (B). 3. A holdback finger (5) is insertable into both yarn loops (A, B) along a lower movement trajectory,
The single thread stitch sewing machine according to claim 1, characterized in that the sewing machine can be lifted from the lower movement track to a position inside the upper movement track, which is installed in a region near the needle plate (31). 4. A needle plate (31) is provided on its lower surface with a cutout (3).
4. A single thread stitch machine according to claim 3, characterized in that the sewing machine has 2) and the holdback finger (5) is movable into the cutout (32). 5. The holding back finger (5) is received by a swinging lever (12) movable relative to the carrier (9), and the carrier (9) is driven by a driving means (oscillating shaft (6)). ), The hold-back finger (5) having a rocking lever (12) and a carrier (9) which are led out by the movement of the carrier (9) in the region of the front reversal position of its lower movement trajectory. The single-thread ring stitch sewing machine according to claim 2 or 3, wherein the sewing machine can be lifted to an upper motion trajectory by a relative motion with the sewing machine. 6. A double lever (1) is provided on the carrier (9) to cause relative movement between the swing lever (12) and the carrier (9).
4) is supported and one end (15) of the double lever (14)
Abuts against the stopper (16) when the holdback finger (5) is in the region of the front reversal position of its motion trajectory, and the other end (17) of the double lever (14) is connected to the swing shaft (6). The sewing machine according to claim 5, characterized in that the sewing machine is drivingly connected to the swing lever (12) via an intermediate member (lever 21) supported by the sewing machine. 7. The relative movement of the carrier (9) and the swing lever (12) is determined by a rotary spring (25) received by the carrier (9), one leg of the rotary spring (25). 7. Single thread ring stitch according to claim 5, wherein the pivoting lever (12) is supported by the pivoting lever (12) and the other leg (27) is supported by the carrier (9). sewing machine. 8. The relative movement between the swing lever (12) and the carrier (9) is performed against the pretension of the rotary spring (25), and the holdback finger (5) is moved upward by its upper orbit. A single thread stitch machine according to claim 7, characterized in that, in the region of the front reversal position, the thread stitch (A) received by the holdback finger is held in an upper motion trajectory.