【０００１】
【産業上の利用分野】
この発明は、一本針上飾り糸付き二重環縫目とその縫目を形成するためのミシンに関するものである。
【０００２】
【従来の技術】
二重環縫いの縫目はＪＩＳによりステッチクラス４００に分類され、本縫いの縫目と比べて伸縮性に富むので、ニット素材の縫製に用いられるうえ、二重環縫いミシンは下糸をボビンに巻き返すことなく糸立てからミシンに直接導くことができるので、作業能率がよく、ニット素材だけでなく、織物やその他、薄物から厚物まで各種の布地の縫製に広く利用されている。
【０００３】
ところが、この二重環縫い目のうち、１本の針と１本のルーパーによって形成されるステッチ形式４０１の縫目は、表面は本縫いと同様に１本の針糸が直線状に表れるのに対して、裏面は下糸（ルーパー糸）がループを形成しているため３本の糸の列となって表れ、縫製後に、縫目部分を脇割りするときに片側に布地が倒れ勝ちになり、また、脇割り部にアイロン掛けするとアタリが下糸側に目立つという難点があった。
【０００４】
この難点を取り除くためには、布地の表面に飾り糸を配設することが考えられる。しかし、二重環縫目の布地の表面に飾り糸を付けた縫目としてＪＩＳにステッチ形式４０８の他、クラス６００に分類される偏平縫い縫目があるが、これらはいずれも左右に配置した複数の針を備えた二重環縫いミシンにおいて、たとえば、特公昭５４−９１１１号、特公昭５４−３３１８８号、特公昭５５−１１０７４号に示された偏平縫いミシンのように、飾り糸振り具を用いて、その左右の針糸間に上飾り糸を掛け渡し、左右の針糸で上飾り糸を蛇行させた状態で布地に縫い付けるようにしたもので、１本の針を用いた二重環縫目のための飾り糸付き縫目やそのための装置は提案されていない。
【０００５】
たとえば、従来の２本の針を左右に配置した偏平縫いミシンを用いて、１本の針とルーパー糸と上飾り糸とにより二重環縫いを行なおうとしても、１本の針糸では上飾り糸の蛇行状態を固定できないので、上飾り糸が不規則に絡みついた縫目となる。
【０００６】
一方、１本の針を用いる一般のミシンにおいて、上飾り糸を縫い付ける方法および装置が、特公昭５７−５４１５３号、特公昭５７−５４１５４号に開示されている。しかしその方法および装置においては、飾り糸を縫い付けるために上糸（針糸）を強制的に側方に排除し、その排除により生じた空隙部に飾り糸を配設するようにしているために、針糸が締まり難く、飾り糸を縫い付けるだけのためであれば十分であっても生地を縫い合わせて連結するためには問題があった。また、針糸を排除し飾り糸を配設するためのルーパーは進退と往復回動の２つの運動を組み合わせた複雑な構造を有し、しかも上糸と飾り糸とに同時に作用させる必要があった。
【０００７】
【発明が解決しようとする課題】
したがって、この発明の第１の課題は、縫い糸が布地の縫製部分の表面と裏面にほぼ同様に表れた新規な二重環縫目を提供することにあり、第２の課題はその縫目を形成するために、従来の二重環縫いミシンに少しの改良を加えるのみでその新規な縫目を形成できるミシンを提供することにある。
【０００８】
【課題を解決するための手段】
この発明にかかわる新規な一本針上飾り糸付き二重環縫目は、引き揃えて１つにまとめられた２本の針糸ＡＡと、１本のルーパー糸Ｂと、１本の上飾り糸Ｃとで構成され、針糸ＡＡのループは布を表側から裏側へ通り抜けて、その裏面で糸Ｂの１つのループを通り抜け、次に糸Ｂの２番目のループと他糸ルーピングし、その他糸ルーピングの部分を布に向って引き付け、上飾り糸Ｃは布の表面上で閉ループを形成し、２本の針糸ＡＡの前記ループがその閉ループ内を通ることにより、上飾り糸Ｃの閉ループをそのループ間の針糸で布の表面に向って引き付けていることを特徴とする。
【０００９】
また、上記の新規な縫目を形成するためのこの発明にかかる二重環縫いミシンは、下端に１本の針を保持しミシン主軸に連動して昇降する針棒と、針棒下方のミシンベッド内において針棒の昇降運動に同調して左右に揺動するルーパーと、前後且つほぼ水平方向の長孔を有しミシンベッド上方の針の右側方に設けられた上飾り糸案内と、その上飾り糸案内の上方において針棒と同期して昇降する目孔を有する昇降糸道と、針棒に平行に配置された往復回動する軸と、その軸に支持されて針の通過線のまわりを左右に往復回動してその左への回動時に先端で縫着前の上飾り糸を引っ掛けて針通過線の手前を左へ案内する上飾り糸用の糸振り具とを備えた二重環縫いミシンにおいて、糸振り具は、糸振り具自身の内周側よりも外周側を深く切り込んだ溝によって先端を上片と下片に分割して、上片を外側に向う突出尖端、下片を内側に向う突出尖端としてそれぞれ形成し、糸振り具の先端が針通過線の前を左へ向って往動するときに、目孔から長孔を経て布地に連なる上飾り糸を糸振り具下片の突出尖端で引っ掛けてその下片と上片との間に保持し、右へ復動するときに上飾り糸が長孔から糸振り具の下片と溝を経て布地に連なることにより形成する閉ループ内に針が降下するようにしたことを特徴とする。
【００１０】
【作用】
この発明の縫目においては、基本的には引き揃えられた２本の針糸ＡＡと、１本のルーパー糸Ｂとによりステッチタイプ４０１の二重環縫目を形成して、重ね合わされた布地をその２本の針糸ＡＡとルーパー糸Ｂで強固に連結することができる。そして、縫目の外観をみると、布地の裏面においてはルーパー糸Ｂが３本の糸の列になって表れ、表面においては引き揃えられた２本の針糸ＡＡと上飾り糸Ｃとが３本の糸の列になって裏面に表れた糸ＢＢＢの列と類似の外観を呈している。また、上飾り糸Ｃは閉ループとなってそのループ内に針糸ＡＡが通っているので、針糸で１縫目毎に規則正しく布地の表面に固定される。
【００１１】
また、この発明のミシンは、上述した通りの手段によって、この出願の発明にかかわる新規な縫目を形成することができる。
【００１２】
【実施例】
この発明の実施例に係る縫目は、図１に示すように引き揃えて１つにまとめられた２本の針糸ＡＡと、１本のルーパー糸Ｂと、１本の上飾り糸Ｃとで構成され、針糸ＡＡのループＡＡＬは布（図示省略）を表側から裏側へ、すなわち図１において上から下へ通り抜けて、その裏面でルーパー糸Ｂの１つのループＢＬ１を通り抜け、次にルーパー糸Ｂの２番目のループＢＬ２と他糸ルーピングし、その他糸ルーピングの部分を布に向って引き付け、上飾り糸Ｃは布の表面上で閉ループＣＬを形成し、２本の針糸ＡＡの針糸ループＡＡＬがその閉ループＣＬ内を通ることにより、上飾り糸Ｃの閉ループを矢印Ｙで示す布進行方向の前後において各針糸ループＡＡＬ間の針糸ＡＡで布の表面に向って引き付けている。
【００１３】
この実施例の縫目において、針糸は２本の糸ＡＡが１つにまとめられて引き揃えた状態になっているものの、２本の糸が撚り合わされた１本の糸となっていないので、布地の表面に表れた縫目は裏面に表れた縫目の３本の糸ＢＢＢの列と同様に、３本の糸ＡＡＣが列状をなしている。このように２本の針糸を引き揃え状態にするには、糸立てに保持させた２個の糸巻きコーンからそれぞれ１本の糸Ａを引出して１個の糸調子器に導くことによって引き揃え、その引き揃えた糸を１本の針の針孔に通して使用するのが非常に簡便であるが、他の引き揃え手段によって引き揃えてもよい。
【００１４】
この発明の縫目を形成するために用いるミシンとその縫目形成工程の１例を図２ないし図５により説明する。ここに示すミシンは、前述した従来の偏平縫いミシンにおいて、上飾り糸用の糸振り具に改良を加えて用いるもので、偏平縫いミシンの基本的な機構は一部省略して説明する。
【００１５】
図２において、上下に昇降運動する針棒１の下端には針留め２が固定されている。この針留め２にはミシン針３を左右に３本並列して取付けられるようになっているが、この実施例においては中央に１本だけ取付けてあり、その針３に２本の針糸ＡＡを引き揃えた状態で通すことができる。針板４（図５参照）を備えたミシンベッド２１内には、針棒１の昇降運動に同調して前後上下に平行四運動し針板の上面に出没する送り歯５と左右に揺動するルーパー６とが設けられ、そのルーパー６には糸通し孔が設けられてルーパー糸Ｂが通される。針板４上には送り歯５に対向して押さえ足７が昇降可能に設けられている。
【００１６】
このミシンの針棒１の近傍の後方には、針棒に同調して往復回動する回動軸８が針棒と平行に配置され、その回動軸８には針通過線ＮＬの後方からその右側に延びるアーム９を介して手前へ円弧状に湾曲して水平方向に延びる糸振り具１０を取付けてあり、その糸振り具１０の先端は、針棒１が昇降するときに、上下に昇降する針３の通過線ＮＬのまわりの手前側を、押さえ足７のやや上方において左右に往復回動するようにしている。この糸振り具１０の回動平面の上方には前後方向に延びる長孔１１をもつ上飾り糸案内１２が配置されるとともに、その上飾り糸案内１２の上方において針棒１と同期して昇降する目孔１３を有する飾り糸用の昇降糸道１４を設けており、さらに針留め２の下部には針糸案内ピン１５を取付けている。
【００１７】
このミシンの糸振り具１０は図３、４、５にも示すように、先端を溝１６によって上片１７と下片１８に分割し、上片１７を外側に向う突出尖端、下片１８を内側に向う突出尖端としてそれぞれ形成するとともに、その溝１６の底部は糸振り具１０の内周側の底部１９よりも外周側の底部２０が深く切り込まれている。
【００１８】
このように構成したミシンにおいて、針棒１（針３）を上昇位置にして押さえ足７の下のミシンベッド２１に布地Ｗを供給し、ミシンを始動すると、布地Ｗは押さえ足７と送り歯５とに挟まれて針板４上を移動するとともに、針３が針棒１の昇降運動に伴って押さえ足７、布地Ｗ、針板４を通過し、針板４の下面においてこれに同調して左右に揺動するルーパー６と協働して縫目を形成する。すなわち針３に通された２本の針糸ＡＡはループとなって針板４の下方でルーパー糸Ｂの１つのループを通り抜け、次にルーパー糸Ｂの２番目のループと他糸ルーピングし、針３の上昇時にその他糸ルーピングの部分を布に向って引き付け、布地Ｗに二重環縫目を形成する。この二重環縫目の布地裏面（下面）における形成過程は、従来の二重環縫目の形成過程とほぼ同じであり詳細説明は省略する。
【００１９】
次に布地Ｗの表面（上面）における上飾り糸付き二重環縫目の形成過程を説明する。このミシンにおいて上飾り糸Ｃは図示を省略した糸調子器から目孔１３、長孔１１を経て布地上に導き、針糸ＡＡは２本の糸を引き揃えて、糸調子器から針糸案内ピン１５を経て針３の目孔に導く。そしてミシンの針板上に布地Ｗを供給して縫目を形成するに際して、針が上死点近傍にあるときには、図２の（ａ）および図３に示すように、糸振り具１０の先端は針通過線ＮＬの手前左側にあって、長孔１１から導かれる上飾り糸Ｃを下片１８で捕捉し、その上飾り糸Ｃは糸振り具１０の溝１６の内周側の底部１９から外周側の底部２０を経て布に連なって閉ループを形成している。
【００２０】
針３が次第に下降するとともに糸振り具１０が右へ移動し、すでに形成されている縫目Ｓも送り歯５により布地Ｗとともに矢印Ｙ方向に前進すると、上飾り糸Ｃの閉ループもやや縦長となって右へ移動し、その移動した閉ループは針通過線ＮＬを囲む状態となり、図２の（ｂ）、図４、および図５の（ａ）、（ｂ）に示すように、針３の先端がその閉ル−プの中に降下する。
【００２１】
引き続き針糸ＡＡも、図２の（ｃ）に示すように、針３とともに上飾り糸Ｃの閉ループ内に降下し、糸振り具１０は右へ後退して糸振り具１０に引っ掛けられている上飾り糸Ｃは下片１８から離脱して針３および針糸ＡＡの周りに巻き付いた状態となる。針３の先端がさらに針板４の下方に降下すると、針糸ＡＡは上飾り糸Ｃを布地Ｗに押さえつけ、針３はルーパー６と協働して針糸ＡＡとルーパー糸Ｂとをルーピングさせて二重環縫目を形成する。
【００２２】
針３が下死点を経て上昇するとき、図２の（ｄ）に示すように糸振り具１０の先端が右死点から針通過線すなわち針糸ＡＡの前を左へ向って往動し、目孔１３から長孔１１を経て押さえ足７の下の布地に連なる上飾り糸Ｃを糸振り具先端の下片突出尖端１８の外側と上片突出尖端１７の内側との間から溝１６の中に導かれるように引っ掛ける。糸振り具１０がさらに左へ進むと、布地から延びる上飾り糸Ｃは図３で示したように溝１６の外周側の底部２０から内周側の底部１９を経て長孔１１、目孔１３に連なって閉ループを形成することとなる。
【００２３】
引続き針３が上死点に達し、糸振り具１０も少し遅れて左死点に至ったのち、上述したように、針３が下降するとともに糸振り具１０が右へ復動するときに、上飾り糸Ｃの閉ループ内に針３が針糸ＡＡとともに降下して、その針糸ＡＡで上飾り糸Ｃの閉ループを布地Ｗの表面に押しつけて固定することとなる。
【００２４】
【発明の効果】
以上にのべたように、この発明の縫目は、本縫いの代わりに広く用いることができ伸縮性や生産性においてすぐれる１本針の二重環縫目において、布地の縫製部分の表面と裏面にほぼ同様の縫い糸の列を表すことができ、縫目部分を脇割りするときに布地を両側に均等に倒し易くなり作業能率が向上するうえ、脇割り部にアイロン掛けしたときのアタリも目立ち難くなるという効果がある。
【００２５】
さらに縫製した布地に表れる縫い糸の列が表と裏とでよく似ているので、縫目の用途を新たに創出できるという効果がある。
【００２６】
また、この発明の新規な縫目を形成するためのミシンは、従来の二重環縫いミシンを用いることができ、また、そのために複雑な動きをする各種の糸振り機構等を付設する必要がなく、少しの改良を加えるのみで、その新規な縫目を形成できるという効果がある。
【図面の簡単な説明】
【図１】この発明にかかる縫目の形態を示す斜視図。
【図２】（ａ），（ｂ），（ｃ），（ｄ）はこの発明の縫目を形成するミシン要部の作用を過程順に示す斜視図。
【図３】図２（ａ）の過程における作用を説明するための平面図。
【図４】図２（ｂ）の過程における作用を説明するための平面図。
【図５】（ａ），（ｂ）は、それぞれ図２（ｂ）の過程における要部を断面で示す側面図、正面図。
１：針棒、３：針、４：針板、５：送り歯、６：ルーパー、７：押さえ足、８：軸、 １０：糸振り具、１１：長孔、１２：上飾り糸案内、１３：目孔、１４：昇降糸道、１６：溝、１７：上片、１８：下片、１９・２０：底部、Ａ：針糸、Ｂ：ルーパー糸、Ｃ：上飾り糸、ＮＬ：針通過線[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double chain stitch with a decorative needle on a single needle and a sewing machine for forming the stitch.
[0002]
[Prior art]
Double chain stitches are classified into stitch class 400 according to JIS and are more elastic than regular stitches, so they are used for sewing knit materials, and double chain stitch machines use bobbins for bobbins. Since it can be guided directly from the thread stand to the sewing machine without being rewound, it has a high work efficiency and is widely used for sewing not only knit materials but also woven fabrics and other various fabrics from thin to thick.
[0003]
However, among the double chain stitches, a stitch type 401 stitch formed by one needle and one looper has a surface in which one needle thread appears linearly in the same manner as the main stitch. On the other hand, the lower side appears as a row of three threads because the lower thread (looper thread) forms a loop, and after sewing, the fabric tends to fall to one side when splitting the seam sideways. In addition, when ironing the side split part, there was a problem that the hit was conspicuous on the lower thread side.
[0004]
In order to eliminate this difficulty, it is conceivable to arrange a decorative yarn on the surface of the fabric. However, in addition to the stitch type 408 in JIS, flat stitches classified into class 600 are provided as decorative stitches on the surface of the double chain stitch fabric, all of which are arranged on the left and right. In a double chain stitch sewing machine provided with a plurality of needles, for example, a flat thread sewing machine such as a flat stitch sewing machine shown in JP-B-54-9111, JP-B-54-33188, and JP-B-55-11074. The upper decorative thread is wrapped between the left and right needle threads, and the upper decorative thread is sewn to the fabric in a state of meandering with the left and right needle threads. No decorative thread or device for it has been proposed for heavy loop seams.
[0005]
For example, using a conventional flat stitch sewing machine in which two needles are arranged on the left and right, if one attempts to perform double chain stitching with one needle, a looper thread and an upper decorative thread, one needle thread will not work. Since the meandering state of the upper decorative thread cannot be fixed, the upper decorative thread becomes a stitch irregularly entangled.
[0006]
On the other hand, in a general sewing machine using one needle, a method and an apparatus for sewing an upper decorative thread are disclosed in JP-B-57-54153 and JP-B-57-54154. However, in the method and the apparatus, the upper thread (needle thread) is forcibly removed to the side in order to sew the decorative thread, and the decorative thread is disposed in the void created by the removal. In addition, the needle thread is difficult to tighten, and there is a problem in sewing and connecting fabrics even if it is sufficient only to sew the decorative thread. Further, the looper for removing the needle thread and arranging the decorative thread has a complicated structure that combines two movements, that is, advance and retreat and reciprocating rotation, and needs to act on the upper thread and the decorative thread simultaneously. Was.
[0007]
[Problems to be solved by the invention]
Accordingly, a first object of the present invention is to provide a novel double-ringed seam in which a sewing thread appears almost on the front and back surfaces of a sewn portion of a fabric, and a second object is to provide a new double-chained seam. It is an object of the present invention to provide a sewing machine which can form a new seam with only a small improvement to a conventional double chain stitch sewing machine.
[0008]
[Means for Solving the Problems]
The novel double chain stitch with a single-needle upper decorative thread according to the present invention is composed of two needle threads AA, one looper thread B, and one upper decoration The loop of the needle thread AA passes through the cloth from the front side to the back side, passes through one loop of the thread B on the back side, and then loops with the second loop of the thread B and the other thread. The part of the thread looping is pulled towards the cloth, the upper decorative thread C forms a closed loop on the surface of the cloth, and the loop of the two needle threads AA passes through the closed loop, thereby forming the closed loop of the upper decorative thread C. Is attracted toward the surface of the cloth by the needle thread between the loops.
[0009]
A double chain stitch sewing machine according to the present invention for forming the above-described novel stitch includes a needle bar which holds one needle at a lower end and moves up and down in conjunction with a sewing machine main shaft, and a sewing machine below the needle bar. A looper swinging left and right in synchronization with the vertical movement of the needle bar in the bed, an upper thread guide provided on the right side of the needle above the sewing machine bed having a front and rear and a substantially horizontal elongated hole, and An ascending and descending yarn path having an eye hole which rises and descends in synchronization with the needle bar above the upper decorative yarn guide, a reciprocating shaft arranged in parallel with the needle bar, and a passing line of the needle supported by the shaft. A thread bobbin for an upper decorative thread that reciprocates around left and right and hooks the upper decorative thread before sewing at the tip when rotating to the left, and guides the left side of the needle passing line to the left. In double chain stitch sewing machines, the thread penetrator cuts deeper on the outer peripheral side than on the inner peripheral side of the thread penetrator itself. The leading edge is divided into an upper piece and a lower piece by a groove, and the upper piece is formed as a protruding point toward the outside, and the lower piece is formed as a protruding point toward the inner side. When moving forward, the upper decorative thread connected to the fabric through the eye hole through the elongated hole is hooked by the protruding point of the lower piece of the thread swinging tool, held between the lower piece and the upper piece, and returned to the right. When moving, the needle descends into a closed loop formed by connecting the upper decorative thread from the long hole to the fabric through the lower piece and the groove of the thread pendulum.
[0010]
[Action]
In the stitch according to the present invention, a double loop stitch of a stitch type 401 is basically formed by two needle threads AA and one looper thread B which are basically aligned, and the superposed fabrics are formed. Can be firmly connected by the two needle threads AA and the looper thread B. Looking at the outer appearance of the seam, the looper thread B appears in a row of three threads on the back surface of the fabric, and the two aligned needle threads AA and the upper decorative thread C appear on the front face. It has an appearance similar to that of the row of yarn BBB appearing on the back side as a row of three threads. Further, since the upper decorative thread C forms a closed loop and the needle thread AA passes through the loop, the upper decorative thread C is regularly fixed to the surface of the fabric for each stitch by the needle thread.
[0011]
The sewing machine of the present invention can form a new stitch according to the invention of the present application by the means described above.
[0012]
【Example】
The stitches according to the embodiment of the present invention include two needle threads AA, one looper thread B, and one upper decorative thread C which are aligned and united as shown in FIG. The loop AAL of the needle thread AA passes through the cloth (not shown) from the front side to the back side, that is, from the top to the bottom in FIG. 1, passes through one loop BL1 of the looper thread B on the back side, and then the looper The other loop is looped with the second loop BL2 of the thread B, and the other thread looping portion is attracted toward the cloth. The upper decorative thread C forms a closed loop CL on the surface of the cloth, and the needles of the two needle threads AA When the thread loop AAL passes through the closed loop CL, the closed loop of the upper decorative thread C is pulled toward the surface of the cloth by the needle threads AA between the needle thread loops AAL before and after the cloth traveling direction indicated by the arrow Y. .
[0013]
In the stitch of this embodiment, the needle thread is in a state where two threads AA are gathered together and aligned, but the two threads are not a single thread in which the two threads are twisted. The three stitches AAC of the stitches on the surface of the cloth are arranged in a row like the three stitches of the stitches BBB on the back surface. In order to bring the two needle threads into the aligned state in this way, one thread A is pulled out from each of the two wound cones held by the thread stand and guided to a single thread tensioner. It is very simple to use the aligned yarn through the needle hole of one needle, but the alignment may be performed by other alignment means.
[0014]
An example of a sewing machine used for forming a stitch according to the present invention and a stitch forming process thereof will be described with reference to FIGS. The sewing machine shown here is the same as the conventional flat stitch sewing machine described above, which is obtained by improving a thread bobbin for an upper decorative thread. The basic mechanism of the flat stitch sewing machine will be partially omitted.
[0015]
In FIG. 2, a needle clamp 2 is fixed to the lower end of a needle bar 1 that moves up and down. Although three sewing needles 3 are attached to the needle holder 2 in parallel on the left and right, only one needle is attached at the center in this embodiment, and two needle threads AA are attached to the needle 3. Can be passed together. In the sewing machine bed 21 provided with the needle plate 4 (see FIG. 5), the feed dog 5 which moves in parallel back and forth and up and down in synchronism with the vertical movement of the needle bar 1 and swings left and right with the upper and lower surfaces of the needle plate. The looper 6 is provided with a threading hole, through which the looper thread B is passed. A presser foot 7 is provided on the needle plate 4 so as to be able to move up and down in opposition to the feed dog 5.
[0016]
Behind the needle bar 1 of the sewing machine, a rotating shaft 8 that reciprocates and rotates in synchronization with the needle bar is disposed in parallel with the needle bar, and the rotating shaft 8 is provided from behind the needle passing line NL. A thread oscillating device 10 which is curved in an arc shape and extends in the horizontal direction is attached via an arm 9 extending to the right side, and the tip of the thread oscillating device 10 is vertically moved when the needle bar 1 moves up and down. The front side of the ascending / descending needle 3 around the passing line NL reciprocates right and left slightly above the presser foot 7. An upper decoration thread guide 12 having a long hole 11 extending in the front-rear direction is arranged above a rotation plane of the thread swinging tool 10, and is moved up and down in synchronization with the needle bar 1 above the upper decoration thread guide 12. An ascending and descending thread path 14 for a decorative thread having a perforated hole 13 is provided, and a needle thread guide pin 15 is attached to a lower portion of the needle clamp 2.
[0017]
As shown in FIGS. 3, 4, and 5, the thread swinging device 10 of the sewing machine has a tip divided into an upper piece 17 and a lower piece 18 by a groove 16, and the upper piece 17 has a protruding tip and a lower piece 18 facing outward. and forming respectively a projecting tip toward the inside, the bottom 20 of the outer peripheral side are deeply cut write Marete than the bottom 19 of the inner peripheral side of the bottom thread swing device 10 of the groove 16.
[0018]
In the sewing machine configured as described above, when the needle bar 1 (needle 3) is in the raised position and the fabric W is supplied to the sewing machine bed 21 below the presser foot 7, the sewing machine is started. 5, the needle 3 moves on the needle plate 4 while the needle bar 1 moves up and down, and passes through the presser foot 7, the cloth W, and the needle plate 4, and synchronizes with the lower surface of the needle plate 4. Then, a seam is formed in cooperation with the looper 6 that swings right and left. That is, the two needle yarns AA passed through the needle 3 form a loop, pass through one loop of the looper yarn B below the needle plate 4, and then loop with the second loop of the looper yarn B, When the needle 3 is raised, the other part of the thread looping is pulled toward the cloth to form a double chain stitch on the cloth W. The process of forming the double chain stitch on the back surface (lower surface) of the fabric is almost the same as the process of forming the conventional double chain stitch, and a detailed description thereof will be omitted.
[0019]
Next, a process of forming a double chain stitch with an upper decorative thread on the surface (upper surface) of the fabric W will be described. In this sewing machine, the upper decorative thread C is guided from an unillustrated thread tensioner through the eye holes 13 and the elongated holes 11 to the cloth, and the needle thread AA draws two threads and aligns the needle thread guide from the thread tensioner. It is led to the eye of the needle 3 via the pin 15. When the fabric W is supplied on the needle plate of the sewing machine to form a stitch, when the needle is near the top dead center, as shown in FIG. 2A and FIG. Is located on the left side in front of the needle passage line NL, and captures the upper decorative thread C guided from the long hole 11 by the lower piece 18, and the upper decorative thread C is a bottom portion 19 on the inner peripheral side of the groove 16 of the thread swinging tool 10. To a cloth through the bottom portion 20 on the outer peripheral side to form a closed loop.
[0020]
As the needle 3 gradually descends, the thread swinging tool 10 moves to the right, and the already formed stitch S also advances in the direction of the arrow Y together with the cloth W by the feed dog 5, and the closed loop of the upper decorative thread C also becomes slightly longer in the vertical direction. And moves to the right, and the moved closed loop surrounds the needle passing line NL. As shown in FIGS. 2 (b), 4, and 5 (a), (b), the needle 3 The tip descends into the closed loop.
[0021]
Subsequently, the needle thread AA also descends into the closed loop of the upper decorative thread C together with the needle 3 as shown in FIG. 2C, and the thread swinging tool 10 retreats to the right and is hooked on the thread swinging tool 10. The upper decorative thread C separates from the lower piece 18 and is wound around the needle 3 and the needle thread AA. When the tip of the needle 3 further descends below the needle plate 4, the needle thread AA presses the upper decorative thread C against the fabric W, and the needle 3 cooperates with the looper 6 to loop the needle thread AA and the looper thread B. To form a double chain stitch.
[0022]
When the needle 3 moves up through the bottom dead center, as shown in FIG. 2D, the tip of the thread swinging tool 10 moves forward from the right dead center toward the needle passing line, that is, in front of the needle thread AA to the left. The upper decorative thread C extending from the eye hole 13 to the cloth under the presser foot 7 via the elongated hole 11 is formed into a groove 16 from between the outside of the lower protruding point 18 and the inner side of the upper protruding point 17 at the tip of the thread pendulum. Hook to be led inside. When the yarn swinging tool 10 further moves to the left, the upper decorative thread C extending from the fabric passes through the bottom portion 20 on the outer peripheral side of the groove 16 through the bottom portion 19 on the inner peripheral side of the groove 16 as shown in FIG. To form a closed loop.
[0023]
Subsequently, after the needle 3 has reached the top dead center and the thread swinging tool 10 has also reached the left dead center with a slight delay, as described above, when the needle 3 is lowered and the thread swinging tool 10 returns to the right, The needle 3 descends together with the needle thread AA into the closed loop of the upper decorative thread C, and the closed loop of the upper decorative thread C is pressed against the surface of the fabric W with the needle thread AA to be fixed.
[0024]
【The invention's effect】
As described above, the seam of the present invention can be widely used in place of the lockstitch, and can be widely used in a single-needle double chain stitch having excellent elasticity and productivity. Nearly the same row of sewing threads can be represented on the back, making it easier to lay the fabric on both sides evenly when splitting the seam side, improving work efficiency, and also reducing the hit when ironing the side split This has the effect of making it less noticeable.
[0025]
Furthermore, since the rows of sewing threads appearing on the sewn cloth are very similar between the front and back sides, there is an effect that a new use of the seam can be created.
[0026]
Further, a conventional double chain stitch sewing machine can be used as a sewing machine for forming a new stitch according to the present invention, and it is necessary to add various thread swing mechanisms and the like which perform complicated movements. Instead, the new seam can be formed with only a small improvement.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a form of a seam according to the present invention.
FIGS. 2 (a), (b), (c) and (d) are perspective views showing the operation of the main part of the sewing machine forming the stitch according to the present invention in the order of steps.
FIG. 3 is a plan view for explaining the operation in the process of FIG. 2 (a).
FIG. 4 is a plan view for explaining the operation in the process of FIG. 2 (b).
5 (a) and 5 (b) are a side view and a front view, respectively, showing a cross section of a main part in the process of FIG. 2 (b).
1: Needle bar, 3: Needle, 4: Needle plate, 5: Feed dog, 6: Looper, 7: Presser foot, 8: Shaft, 10: Thread swinging tool, 11: Slot, 12: Upper decorative thread guide, 13: Eye hole, 14: Elevating thread path, 16: Groove, 17: Upper piece, 18: Lower piece, 19/20: Bottom, A: Needle thread, B: Looper thread, C: Top decorative thread, NL: Needle Passing line
