JP2569335Y2 - Threading device of scoop sewing machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread reeling device for adjusting and tensioning a thread supplied to a needle in order to realize stable sewing in a scoop sewing machine.

[0002]

2. Description of the Related Art A scooping sewing machine used for sewing the edge of a fabric folded back to the back side, such as trousers, slacks, and skirt hem blind stitches, with almost no stitching on the front side, has a main shaft rotating. A needle that is curved in an arc shape is attached to the tip of a swing arm (needle swing arm) that swings according to the movement of the needle that moves along a curved circle due to the swing of the needle swing arm. This is a sewing machine that forms a stitch by operation of a related looper.

FIG. 8 is an explanatory view of a process of forming a stitch by a scoop sewing machine. A needle 1 curved in an arc shape as shown in the figure is attached to the tip of a needle swing arm 2, and swings the needle swing arm 2 to perform a reciprocating operation of a predetermined stroke along a curved line. On the other hand, the looper 3 is disposed behind the advance / retreat operation area of the needle 1 and located near the stroke end on the advance side, and has a base 3a having an axis substantially perpendicular to the operation direction of the needle 1; The front end of the base 3a is provided with a pair of thread hooks 3b and 3c which are protruded in a forked manner. The forward and backward movement of the base 3a in the axial direction, the rotation of the base 3a around the axis, and the needle 1 And moving in the operation direction. In the drawing, the operation of the needle 1 at each operation stage is indicated by black arrows, and the operation of the looper 3 is indicated by white arrows.

FIG. 8 (a) shows a state in which the needle 1 is retreating from the stroke end on the advance side, and the retraction causes a thread hole 1a (FIG. ), (D)), the loop L formed by the needle thread A inserted remains. At this time, the looper 3 is, as shown in FIG.
3b, 3c are kept in the horizontal position and advanced.
The loop L is captured above the needle 1 by 3c.

Further, the needle 1 continues the retreating operation, and the looper 3 advances to a predetermined position and rotates by 90 ° around the axis. As a result, the loop L caught by the thread hooks 3b, 3c is fed out while being expanded by the thread hooks 3b, 3c in the vertical position, as shown in FIG. 8B. During this time, a predetermined feed in the direction of the arrow is applied to the sewn cloth by the operation of a feeder (not shown), and the looper 3 moves in the retreating direction of the needle 1 together with the advance operation, and is held by the looper 3. The loop L of the needle thread A moves obliquely forward (upstream in the feed direction) relative to the previous capture position while being further fed out.

Thereafter, the needle 1 shifts to the advance operation, and at the same time, encounters the looper 3 which shifts to the retreat operation at a predetermined position.
The looper 3 is inserted between the thread hooks 3b and 3c. At this time, the needle thread A inserted through the thread hole 1a at the tip of the needle 1 is as shown in FIG.
As shown in (c), the sheet passes through the loop L held by the two thread hooks 3b and 3c, and further advances to penetrate the folded edge of the sewn cloth which is pushed upward by the operation of the push-up plate (not shown).

Immediately before the needle 1 reaches the stroke end on the advance side, the looper 3 returns to a predetermined retracted position by the movement of the needle 1 in the advance direction and the retreat operation of the base 3a in the axial direction. As a result, the loop L is pulled out of the threading portions 3b and 3c,
As shown in FIG. 8D, the needle 1 is held by a double needle thread A along the top and bottom of the needle 1. Next, the needle 1 shifts to a retreat operation while leaving a new loop L at the stroke end,
At approximately the same time, the looper 3 starts to advance while rotating about the axis, and is inserted through the loop L while keeping the thread hooking portions 3b and 3c at the leading ends in the horizontal position, and returns to the state of FIG. Thereafter, by repeating the above-described operation, the stitches B as shown in FIG. 8D are sequentially formed.

[0008]

The sewing with the scoop sewing machine as described above is performed by the process in which the needle 1 is advanced and inserted into the loop L held by the looper 3 and the needle 1 is retracted. The process in which the remaining loop L is captured by the looper 3 and the process in which the loop L captured by the looper 3 is routed proceed while being sequentially repeated, and the feeding of the needle thread A is performed as follows.
The operation is performed by the above-described operation and the feeding operation of the looper 3 when the loop L is handled. Therefore, if the applied tension of the needle thread A is kept constant during the sewing, the following inconvenience occurs.

That is, when the tension applied to the needle thread A is uniformly increased, the loop L caught by the advance of the needle 1 is strongly tightened. In particular, when sewing a thin cloth, wrinkles and twists are generated in the cloth. As a result, the loop L formed by the retreat of the needle 1 becomes small, making it difficult to catch by the looper 3, making it easy to skip stitches, lowering the finished quality of the sewn product, and causing the needle thread by the operation of the looper 3. There is a possibility that the feeding of the loop A may be hindered, and the advance route of the needle 1 may be disturbed, and it may be difficult to transfer the loop L between the needle 1 and the looper 3.

On the other hand, if the applied tension to the needle thread A is uniformly reduced, the feeding state of the needle thread A changes due to a slight change in the applied tension during the operation of the looper 3, and the slack of each eye is reduced. The stitches B having various degrees are formed, which leads to a decrease in the finished quality in the opposite sense. In addition, depending on the type of the needle thread A, the loop L remaining when the needle 1 retreats falls down and is caught by the looper 3. And skipping may occur.

In order to solve the above-mentioned difficulties, Japanese Patent Publication No. 43-26076 discloses a known thread tensioner which applies tension to the needle thread A by clamping between a pair of thread clamping plates pressed by a spring. The gap between the thread clamp plates is changed by the cam means attached to the main shaft of the sewing machine, and the needle 1 is retracted during the retracting operation which occurs in conjunction with the rotation of the main shaft, that is, the looper 3 during the retracting operation. A scooping sewing machine provided with an automatic thread tensioner that automatically releases the tension applied to the needle thread A during the feeding of the needle thread A by the above operation is disclosed.

According to this configuration, the advance operation of the needle 1 is performed under a relatively high applied tension, the loop L is properly captured by the looper 3, and the needle 1 is appropriately tightened by the tightening caused by the advance. While the seam B is formed, the subsequent feeding of the needle thread A by the operation of the looper 3 is performed under a weak applied tension, and the feeding can be reliably performed. However, two-step tension setting depending on the type of fabric to be sewn involves annoyance, and the timing of the tension change cannot be changed. There is a disadvantage that it is impossible to respond to changes.

In Japanese Patent Publication No. 60-46997, there is provided a needle thread feeder which feeds a predetermined length of the needle thread A during the retreating operation of the needle 1 by utilizing the swinging operation of the needle swing arm 2, A scooping sewing machine is disclosed in which the subsequent feeding of the needle thread A by the looper 3 is performed within the range of the feeding by the needle thread feeding device.

According to this configuration, there is no possibility that dispensing by the operation of the looper 3 is obstructed irrespective of the tension applied to the needle thread A, and the tension is appropriately tightened by setting the tension in one step according to the type of the cloth. A stitch B can be obtained, and it is possible to cope with a change in sewing conditions by adjusting the feeding length by the needle thread feeding device. However, since the feeding of the needle thread A by the looper 3 is performed with almost no resistance, the feeding of the needle thread A is caused by a slight change in the applied tension during the operation of the looper 3 as in the case where the needle thread A is excessively loosened. The state changes,
There is a problem in that the seams B having poor uniformity are formed and the finished quality is deteriorated.

Therefore, conventionally, a scooping sewing machine having both the above-described automatic thread tensioner and needle thread feeder and complementing each of the above-mentioned disadvantages has been put to practical use. In, according to sewing conditions such as stitch pitch, feed speed, and the type of fabric,
The adjustment of the set tension in the automatic thread tensioner and the adjustment of the feeding amount in the needle thread feeder have to be performed, and there is a problem that this adjustment requires a high level of skill and a great deal of labor.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and does not require complicated adjustment work according to sewing conditions, and a thread reeling of a scooping sewing machine capable of stably obtaining appropriately tightened stitches. It is intended to provide a device.

[0017]

According to the present invention, a threading device for a scoop sewing machine according to the present invention includes a needle for swinging a needle swing arm in accordance with the rotation of a main shaft, a needle which is attached to the tip of the needle and having a predetermined stroke. In the threading device of a scooping sewing machine, which pierces the cloth to which the feed is applied including before and after reaching the stroke end on the advance side, and forms the sewing with the needle thread supplied to the needle, An automatic thread tensioner that releases the applied tension of the needle thread before and after the stroke end on the advance side in conjunction with the rotation of the main shaft, and interlocks with the swinging of the needle swing arm, during the needle retreat operation. A needle thread feeder that feeds a predetermined length of needle thread, and is disposed between the needle thread feeder and the automatic thread tensioner, and interlocked with the feed,
A needle thread retraction device is provided for feeding out the needle thread on the side of the automatic thread tensioner in the first half of the operation period, and a needle thread retraction device for drawing back the needle thread on the side of the needle thread feeder in the latter half.

[0018]

In the present invention, during the advance operation of the needle, the tension applied to the needle thread is released by the operation of the automatic thread tensioner, and during the first half of the operation of the needle thread retractor generated during this time, the automatic thread tensioner side is operated. Pay out the needle thread securely. In addition, the subsequent operation of the latter half of the needle thread retraction device pulls back the needle thread previously fed by the needle thread dispenser at the beginning of the retreating operation of the needle, and causes a large amount of slack at the tip of the needle. Prevent the formation of loops. Further, by the operation of the needle thread feeder that is generated thereafter, the needle thread corresponding to the slack generated by the retraction is fed out in preparation for the next advance of the needle.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a perspective view showing a main part of a scoop sewing machine provided with a thread reeling device according to the present invention. 8, reference numeral 1 denotes a needle, 2 denotes a needle swing arm, and 3 denotes a looper. The base of the needle swing arm 2 is the sewing machine head 4
The needle 1 is fixed to a swinging shaft 20 projecting from the front of the needle 1. The needle 1 which is curved in an arc shape is detachably attached to the tip.

A swing shaft 20 for fixedly supporting the swing arm 2
Is connected to a needle driving mechanism built in the sewing machine head 4 and swings around an axis in accordance with rotation of the main shaft S (see FIG. 2). Due to the swing of 2, the needle 1 moves forward and backward by a predetermined stroke along its own curved line as described above. On the other hand, the looper 3 has a base portion extended inside the sewing head 4.
3a (see FIG. 8) is connected to a looper drive mechanism built in the sewing machine head 4, and is provided at the rear side of the advance / retreat operation area of the needle 1 so as to face the stroke end on the advance side. In other words, in accordance with the rotation of the main shaft S transmitted via the looper drive mechanism, the base 3a moves back and forth in the axial direction, and the base 3a rotates around the axis. , The movement of the needle 1 in the operating direction.

The main shaft S is connected to a base of the sewing machine head 4 in a manner substantially perpendicular thereto.
The needle drive mechanism and the looper drive mechanism are connected to the main shaft S at a continuous portion between the sewing machine head 4 and the sewing machine bed 5 and extend toward the tip of the sewing machine head 4. ing. Further, a feed device (not shown) is formed below the leading end of the sewing head 4, and this feed device is also connected to the main shaft S via a feed drive mechanism built in the sewing head 4.

Below the needle 1 and the looper 3, the tip of a sewing machine arm 6 extending in a manner substantially orthogonal to the sewing head 4 is located. A feeding member for giving a feed to the fabric by the operation of the feed mechanism disposed at the lower end of the sewing machine head 4, a needle receiver for supporting the side portion when the needle 1 advances, and the fabric in response to the advance of the needle 1. Various components for assisting sewing are provided, such as a push-up plate pushed up from below.

The scooping sewing machine constructed as described above is equipped with a thread reeling device according to the present invention including an automatic thread tensioner 50, a needle thread reeling-out device 8, and a needle thread retractor 9. The automatic thread tensioner 50 has the same configuration as that disclosed in Japanese Patent Publication No. 43-26076, and is arranged on the upper surface of the sewing machine bed 5 in the middle.

A constant tension applying device 40 is disposed on the upper surface of the base end of the sewing machine head 4. This constant tension applicator 40
Is a screw shaft 41 erected on the upper surface of the sewing machine head 4, a thread clamp plate 42 fixedly mounted on the base end of the screw shaft 41, and a thread clamp plate 42 above the thread clamp plate 42 along the screw shaft 41. A thread clamp plate 43 slidably inserted and an adjusting nut 44 screwed to the tip of the screw shaft 41 are provided. A coil spring 45 is provided between the adjusting nut 44 and the thread clamp plate 43.
The thread clamp plate 43 is pressed against the thread clamp plate 42 by the spring force of the coil spring 45, and the needle thread A inserted between the plates 42 and 43 corresponds to the spring force as described later. It is configured to apply a constant tension. The applied tension can be appropriately set by adjusting the spring force of the coil spring 45 by operating the adjustment nut 44.

FIG. 2 is an enlarged sectional view of the automatic thread tensioner 50. As shown in FIG. 1 and FIG. 1, the automatic thread tensioner 50 includes a screw shaft 51 erected on the upper surface of the sewing machine bed 5, a pair of thread clamp plates 52, 53, and a screw, similarly to the constant tension applying device 40. An adjusting nut 54 is screwed onto the end of the shaft 51. The thread clamping plate 53 is clamped by the spring force of a coil spring 55 interposed between the adjusting nut 54 and the upper thread clamping plate 53. Press on plate 52, both plates 5
The tension is applied to the needle thread A between 2 and 53.

On the other hand, unlike the configuration of the constant tension applicator 40, a split groove 56 having a predetermined depth from the upper end is formed on the screw shaft 51 of the automatic thread tensioner 5, as shown in FIG. As described above, a part of the upper thread clamp plate 53 is engaged with the split groove 56. Further, a hollow portion 57 extending from the bottom of the split groove 56 to the inside of the sewing machine bed 5 is formed in the shaft center of the screw shaft 51, and a pushing rod 58 is slidably slidable in the hollow portion 57. The lower end of the push rod 58 is abutted on an eccentric cam C formed in the sewing machine bed 5 in the middle of the main shaft S, and the upper end of the push rod 58 is engaged with the split groove 56. Dish
Part of 53.

In the automatic thread tensioner 50 constructed as described above, the pushing rod 58 moves up and down in response to the rotation of the eccentric cam C interlocking with the main shaft S.
2 and the coil spring 55 as shown in FIG.
The thread clamp plate 53 is pushed upward against the spring force of, and the tension applied to the needle thread A clamped between the thread clamp plate 53 and the thread clamp plate 52 is released. On the circumference of the eccentric cam C, one projecting portion for upward movement of the push rod 58 is formed, and the release of the tension applied to the needle thread A is released during one rotation of the main shaft S. The rotation is performed during the push-up of the push rod 58 by the eccentric cam C. During this time, the tension application by the constant tension application device 40 is continued.

Further, the needle thread feeder 8 is provided with
-46997, the needle swing arm 2
A substrate 80 fixed to the front surface of the sewing machine by a screw, a thread winding plate 81 attached to an upper portion of the substrate 80, and a thread path plate 82 fixed to an upper end of the sewing machine head 4.

The threading plate 81 is attached with a set screw 83 inserted at the base end thereof to the substrate 80 via a spring washer with a tip protruding above the substrate 80, and a force exceeding a predetermined amount is applied. By adding to the tip, the set screw 83 can be rotated about a pivot.
On the other hand, the thread path plate 82 is provided with the needle swing arm 2 toward the advance side of the needle 1.
Is fixed at a position approaching the threading plate 81 when swinging, and moving away from the threading plate 81 when swinging toward the retreating side. Needle thread A
Passes through a thread hooking hole formed in the thread guide plate 82 and a thread hooking hole at the tip of the threading plate 81 in this order to reach the needle 1, and is inserted into the thread hole 1a at the tip of the needle 1 as shown in FIG. Threading plate set according to the swing of the needle swing arm 2 toward the retreating side.
It is fed out with the separation of 81 and the thread path plate 82.

Further, the needle thread pull-back device 9 includes the sewing machine head 4
A base 90 fixed to one side is covered with a cover plate 91 to cover the upper part. FIG. 3 is an enlarged perspective view of the needle thread retractor 9 shown with the cover plate 91 removed. As shown in the drawing, a long hole 92 penetrating the base 90 from the front to the back is extended along the longitudinal direction of the sewing machine head 4. A pair of thread guide plates 93 and 94 having thread catch holes for inserting A are provided upright. A support plate 95 is provided upright on an extension of the other end of the elongated hole 92, and the cover plate 91 is fixed to the upper portion of the support plate 95 by screwing one side thereof to the elongated hole 92. It is attached so as to cover the top.

The support plate 95 holds the distal end of a guide rod 97 in the form of a small-diameter round bar between the support plate 95 and a holding plate 96 fixed by setscrews 98 along the entire side surface. The base end of the guide rod 97 extends along the upper center of the elongated hole 92 and is fixed near one end of the elongated hole 92. The guide bar 97 is inclined with its tip side, that is, the side sandwiched by the holding plate 96 facing upward (FIGS. 5 to 7).
), The degree of the inclination depends on the holding plate 96 with respect to the supporting plate 95.
By changing the fixing position of the
It can be adjusted appropriately within the length range of 98 insertion holes.

The threading rod 10 is inserted through the elongated hole 92. On the upper side of the threading rod 10 projecting above the base 90, a guide plate 12 is screwed and fixed on one side with a spacer plate 11 interposed therebetween, and the guide is inserted into a gap between the threading rod 10 and the guide plate 12. The rod 97 is inserted. On the other hand, the lower end of the threading rod 10 extending below the base 90 is fixed to a connection collar 14 fitted to a feed link pin 13 protruding to one side of the sewing head 4.

The feed link pin 13 protrudes from the shaft of the feed link of a feed drive mechanism (not shown) built in the sewing machine head 4, and is used to feed the cloth generated in connection with the rotation of the main shaft S by the operation of the feed drive mechanism. A pin which rotates within a predetermined angle range during non-operation, and has a lower end connected to the feed link pin 13, has an upper portion on which the guide plate 12 can be moved during non-operation of fabric feeding. Swings along the elongated hole 92 with the guide rod 97 inserted between them as a guide.

The needle thread retraction device 9 configured as described above is provided with the needle thread A that has passed through the automatic thread tensioner 50 and the constant tension applying device 40.
As shown in the drawing, the needle thread A is first inserted into the thread hooking hole of the outer thread path plate 93, and then is wound over the guide rod 97 on the front side of the threading rod 10 and further inside. The thread is supplied to the needle thread feeder 8 through the thread hole of the thread path plate 94. Thus, the needle thread A is
Will be fed out along the guide rod 97, and this feeding is performed from the same side while the applied tension in the automatic thread tensioner 50 is released, but in other cases, It is used for pulling back the needle thread A fed by the needle thread feeder 8.

FIG. 4 is a time chart showing the operation contents of the automatic thread tensioner 50, the needle thread feeder 8 and the needle thread retraction device 9 in relation to the advance / retreat operation of the needle 1 and the looper 3 and the feed operation. FIGS. 5, 6, and 7 are explanatory diagrams of the operation states of the automatic thread tensioner 50, the needle thread feeder 8, and the needle thread retractor 9 at each operation timing.

The horizontal axis in FIG. 4 is the rotation angle of the main shaft S starting from the advance start point of the needle 1, and as shown in FIG.
One advance / retreat operation is performed during one rotation of the spindle S. On the other hand, the looper 3 makes a complicated movement as described above, but if attention is paid only to the forward / backward movement, the looper 3 performs the retreat operation when the needle 1 advances, and
The exit operation of the looper 3 is performed at the time of retreat, and the transition from the exit to the advance of the looper 3 occurs slightly before the transition of the needle 1 from the advance to the exit. The feeding of the cloth is performed within a range of approximately 1/3 of the entire rotation angle of the main shaft S, with the advance start point of the needle 1, that is, the time point when the needle 1 is at the most retracted position as its center.

The release of the tension in the automatic thread tensioner 50 is performed in a range from when the needle 1 is at a substantially middle position of the advance stroke to immediately after reaching the advance stroke end. is there. The timing of releasing the tension can be freely set by the shape of the eccentric cam C formed in the middle of the main shaft S.

On the other hand, the feeding of the needle thread A by the needle thread feeder 8 is performed during the swinging of the needle swing arm 2 for retracting the needle 1 as described above. Since the degree of separation between the thread winding plate 81 and the thread path plate 82 is small, the actual unwinding starts at a stroke end on the retreat side from when the needle 1 is at a substantially intermediate position of the retreat stroke as shown in the drawing. It is done until it reaches.

Further, in the needle thread pull-back device 9, as described above, the feeding lever 10 which is generated during the non-operation period of the feeding is provided.
Of the needle thread A is performed in accordance with the swing of the needle thread A. In the initial period of the non-operation period of the feed, the needle thread A is not fed out because the swing angle of the feeding lever 10 is small, and the upper portion of the feeding lever 10 has a swinging motion as shown in FIG. There is provided a retreat area 10a that retreats in a direction opposite to the direction, the swing angle of the feeding lever 10 exceeds a predetermined angle in the latter half of the non-operating period, and the protruding part on the guide rod 97 is formed in the retreat area 10a. (See FIG. 7).
Is not carried out.

That is, the feeding of the needle thread A by the needle thread retraction device 9 is not performed in the entire area of the non-operation period of the feeding, but is performed only in a predetermined range in the middle of the non-operation period. It can be set as appropriate by changing the standing positions of the thread guide plates 93 and 94 and changing the degree of inclination of the guide bar 97 by adjusting the position of the holding plate 96. The feeding range includes the time point immediately after the tension is released by the automatic thread tensioner 50 and immediately before the start of feeding by the needle thread feeder 8, substantially at the time when the needle 1 reaches the stroke end on the advance side. Is set by

FIG. 5 shows the operation state of each part at the time shown as T ₁ in FIG. At this time, the needle thread A is being fed by the forward swing of the feeding arm 10 in the needle thread retraction device 9, but at this time, the automatic thread tensioner 50 applies the applied tension of the needle thread A as shown in the drawing. Since this is in a state of being reduced, this feeding is performed mainly so as to pull out the loose needle thread A from the automatic thread tensioner 50 side. The positional relationship between the needle 1 and the looper 3 at this time is as follows.
It is in the state of FIG.

Thereafter, in the needle thread retraction device 9, the swinging of the pay-out arm 10 proceeds, and the further feeding of the needle thread A is performed. The tension applied to the needle thread A in the automatic thread tensioner 50 is Immediately after reaching the stroke end on the advance side, the tension returns to the normal tension, and the feeding is performed so as to pull back the needle thread A on the needle thread feeder 8 side. During this time, the needle 1 and the looper 3 are in the state shown in FIG. 8A to FIG. 8B, and the loop L remaining at the tip of the needle 1 is reduced in size as the needle thread A is pulled back while being stable. And the looper 3 is securely captured.

[0043] Figure 6 is a point shown as T ₂ in FIG. 4, that is, the operation of each section the state at a certain point in the middle of the needle 1 is retracted operation. At this point, as shown, the automatic thread tensioner
50 is in a normal tension application state, but in the needle thread retraction device 9, the needle thread A on the guide bar 97
The process proceeds to 10a, and the needle thread A has been loosened due to the previous feeding. Accordingly, the feeding of the needle thread A by the needle thread feeder 8 following the retreating operation of the needle 1 is performed within the above-mentioned slack range without any resistance, and the operation of the looper 3 during this time causes the operation shown in FIG. 8) to 8 (c), there is no risk of hindering the operation of the loop L.

[0044] Figure 7 is a point shown as T ₃ in FIG. 4, that is, the operation of each section state immediately after the needle 1 has retreat converted from input operation in the advanced operation. As shown in the drawing, at this time, the feeding rod 10 has returned to the rear in the needle thread retraction device 9, and the slack of the needle thread A in the needle thread retraction device 9 during the transition from FIG. 6 to FIG. Needle 1 is
The operation can be shifted to the advance operation in a state where the needle thread A is sufficiently fed by the needle thread feeder 8.

[0045]

As described in detail above, in the thread reeling device according to the present invention, the automatic thread tensioner for releasing the applied tension of the needle thread and the needle thread dispenser for reeling out the needle thread during the retreat operation of the needle. In addition, there is provided a needle thread retractor which operates in conjunction with the non-operation of the feed and extends between the time when the needle is advanced and the time when the needle is retracted. Feeds out the needle thread on the automatic thread tensioner side where the applied tension has been released, and pulls back the needle thread previously fed by the needle thread feeder during the retreating operation of the needle. The formation of a large needle thread loop due to loosening can be prevented, and the looper can be reliably captured, while the operation of the needle thread loop by the subsequent operation of the looper is performed without any trouble. The thread return of the thread pull-back device is applied to the swing of the thread reel rod corresponding to the momentum of the feed. Since Ri is carried out, have been made thread take-up amount corresponding to the magnitude of the feed, such as moderately tight seam is formed stably, the present invention is an excellent effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a scoop sewing machine provided with a thread reeling device according to the present invention.

FIG. 2 is an explanatory diagram of an operation of the automatic thread tensioner.

FIG. 3 is an enlarged perspective view of the needle thread pullback device.

FIG. 4 is a time chart showing the operation timing of each part of the yarn reeling device according to the present invention.

FIG. 5 is an explanatory view of the operation of the thread reeling device according to the present invention.

FIG. 6 is an explanatory view of the operation of the thread reeling device according to the present invention.

FIG. 7 is an explanatory view of the operation of the thread reeling device according to the present invention.

FIG. 8 is an explanatory diagram of a forming process of a stitch by a scoop sewing machine.

[Explanation of symbols]

 1 Needle 2 Needle swing arm 3 Looper 4 Sewing head 5 Sewing machine bed 6 Sewing arm 8 Needle thread feeder 9 Needle thread retractor 10 Threading rod 12 Guide plate 13 Feed link pin 40 Constant tension applying device 42 Thread clamp plate 43 Thread clamp Plate 44 Adjustment nut 45 Coil spring 50 Automatic thread tensioner 52 Thread clamp plate 53 Thread clamp plate 54 Adjustment nut 55 Coil spring 58 Push rod 81 Threading board 82 Thread path board 92 Slotted hole 93 Thread path board 94 Thread path board 97 Guide rod A Needle thread C Eccentric cam S Spindle

Claims (1)

(57) [Scope of request for utility model registration] 1. A swinging movement of a needle swing arm in accordance with the rotation of a main shaft causes a needle, which is attached to the tip of the needle swinging arm, to move forward and backward by a predetermined stroke so that the needle reaches a stroke end on the advance side. In a threading device for a scooping sewing machine, which penetrates a fabric to which a feed is given including front and rear, and forms a sewing with a needle thread supplied to the needle, interlocking with the rotation of the main shaft, the front and rear of the stroke end on the advance side. An automatic thread tensioner for releasing the applied tension of the needle thread, a needle thread feeder for feeding a predetermined length of the needle thread during the retreating operation of the needle in conjunction with the swing of the needle swing arm, and the needle It is disposed between the yarn feeder and the automatic thread tensioner, interlocks with the feed, and pays out the needle thread on the automatic thread tensioner side in the first half of the operation period.
A needle thread pull-back device for pulling back the needle thread on the side of the needle thread pay-out device in the latter half;