JP3861954B2

JP3861954B2 - Upper thread tension applicator for sewing machine

Info

Publication number: JP3861954B2
Application number: JP34705597A
Authority: JP
Inventors: 宣今枝
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 1997-12-01
Filing date: 1997-12-01
Publication date: 2006-12-27
Anticipated expiration: 2017-12-01
Also published as: JPH11156076A

Description

【０００１】
【発明の属する技術分野】
本発明は、上糸供給源から天秤に至る上糸経路中に設けられ上糸に張力を付与する為のミシンの上糸張力付与装置に関し、特に主張力付与機構（糸調子機構）の上流側に副張力付与機構を設け、この副張力付与機構に張力調整機構を設けたものに関する。
【０００２】
【従来の技術】
一般に、ミシンでは糸駒から天秤に至る上糸経路中に糸調子皿を含む主張力付与機構を設けて上糸に張力を付与するように構成してある。この主張力付与機構ではその調整ダイアルを操作して張力を調整可能になっている。ところで、一般に太い上糸を使用するときには下糸との張力のバランスをとるため、生地の厚さに応じた適切な糸調子とするために、細い上糸を使用する場合と比較して上糸の張力を大きく設定しなければならない。
【０００３】
前記主張力付与機構の調整ダイアルを操作することで、上糸の張力を上糸の太さに応じて調整可能ではあるが、この主張力付与機構よりも上流側に副張力付与機構を設けて上糸に抵抗を付加することで、上糸張力の調整を殆ど省略したり調整の頻度を少なくする技術が提案されている。
例えば、実開平５−３９４７８号公報に記載のミシンの上糸張力付与装置においては、副張力付与機構に、ベース板、板バネ状の押え板、これらの間に挟着された薄いスペーサ、ベース板と押え板の間にスペーサを介して形成された糸通過隙間などを設け、ベース板にスペーサと押え板とをかしめピンにて固定し、その他細かな工夫を施し、太い上糸が通過する際にはベース板と押え板とで上糸に抵抗を付与する一方、スペーサの厚さ位の直径の細い上糸が通過する際には上糸に殆ど抵抗を付与しないように構成してある。
【０００４】
一方、実開平２−４５７４号公報に記載のミシンの上糸テンション装置では、糸調子皿のすぐ下流側に、固定板に板バネからなる押えバネを重ねてそれらの間に上糸の糸通過隙間を形成し、調整ネジにより糸通過隙間の大きさを調整し、上糸の張力を調整可能に構成してある。
【０００５】
【発明が解決しようとする課題】
前記実開平２−４５７４号公報の上糸テンション装置では、押えバネの板厚が0.2 ｍｍ程度と薄いため、その押えバネをバネ定数の大きな材質で構成する必要があるだけでなく、糸通過隙間の設定に極めて高い寸法精度が要求される。しかも、調整ネジが１本しかなく、固定板と押えバネ間の糸通過隙間は断面楔形状の隙間となるため上糸の通過位置が変動すると上糸に作用する抵抗が変動するため上糸張力を安定させることが困難である。
【０００６】
前記実開平５−３９４７８号公報の副張力付与機構においては、押え板として0.6 ｍｍ程度のステンレス板を適用するものの、薄い板バネ状の押え板により糸通過隙間を設定するため、糸通過隙間の設定に極めて高い製作精度が要求される。そして、この副張力付与機構には、糸通過隙間の大きさ又は押え板の弾性付勢力を調整する機構がないので、製作誤差等に起因する張力のバラツキがあっても上糸張力を調整することができず、上糸張力を安定させることが難しい。
【０００７】
また、薄い板バネ状の押え板で上糸に抵抗を付加する構造であるうえ、糸通過隙間の長さが短いため、上糸に十分大きな抵抗を付加できず、上糸張力を高めるには限度がある。例えば、太い上糸の場合には60〜90ｇｆ程度の張力を付与するのが望ましいが、実際には20〜40ｇｆ程度の張力しか付与できなかった。しかも、糸通過隙間を通過中の糸に撚りがあると張力が大きく変動するが、従来の副張力付与機構では、上糸の撚りを解消する為の対策が殆ど講じられていない。
【０００８】
本発明の目的は、副張力付与機構において上糸に付与する張力を安定させること、その張力を強くし且つ調整可能にすること、糸通過隙間よりも上流側で糸の撚りを極力解消すること、等である。
【０００９】
【課題を解決するための手段】
請求項１のミシンの上糸張力付与装置は、ミシンの上糸供給源から天秤に至る上糸経路中に設けられ、上糸に張力を付与する為の上糸張力付与装置において、上糸に張力を与えその張力の調整操作が可能な主張力付与機構と、この主張力付与機構よりも上糸供給源側に設けられベース板と張力付与板との間に介在させたスペーサを介してベース板と張力付与板との間に糸通過隙間を形成した副張力付与機構とを備え、前記副張力付与機構に、張力付与板をベース板の方へ弾性付勢する付勢機構と、この付勢機構に設けられた張力調整機構とを設け、前記付勢機構の第１の付勢力入力部を張力付与板のうちの糸通過隙間の上糸経路を形成する部分の少なくとも一部に当接させたことを特徴とするものである。
【００１０】
この上糸張力付与装置では、糸供給源から出た上糸が上糸経路を通って天秤に至る間に、最初に副張力付与機構により上糸に張力が付与され、次に主張力付与機構により上糸に張力が付与される。主張力付与機構で付与する張力は調整操作可能である。副張力付与機構においては、ベース板と張力付与板との間に介在させたスペーサを介してベース板と張力付与板との間に糸通過隙間が形成され、付勢機構により張力付与板がベース板の方へ弾性付勢されているため、糸通過隙間を通る上糸にベース板と張力付与板とで抵抗が付加され張力が付与される。付勢機構に設けられた張力調整機構により、付勢機構の弾性付勢力を調整することで上糸の張力を調整できる。即ち、付勢力を強化すると張力が増大し、付勢力を弱めると張力が減少する。
【００１１】
ここで、前記付勢機構の第１の付勢力入力部を張力付与板のうちの糸通過隙間の上糸経路を形成する部分の少なくとも一部に当接させてあるため、張力付与板の変形や製作誤差等の影響を受けることなく、第１の付勢力入力部から張力付与板のうちの糸通過隙間の上糸経路を形成する部分の少なくとも一部に弾性付勢力が入力され、その付勢力が上糸に伝達されるため、上糸に作用する抵抗を強めるとともに安定させ上糸の張力を強めるとともに安定させることができ、張力付与板の製作精度の要求も緩和されて有利になる。
【００１２】
請求項２のミシンの上糸張力付与装置は、請求項１の発明において、前記付勢機構は、第１の付勢力入力部から上糸経路と略直交する方向へ離隔して位置する第２の付勢力入力部を有することを特徴とするものである。それ故、付勢機構の第１，第２付勢力入力部から張力付与板に付勢力が入力されても、張力付与板とベース板とが平行に保持され、張力付与板がベース板に対して傾くことがないから、糸通過隙間を通過する上糸の位置が変動しても、上糸に作用する抵抗が変動ぜず上糸張力が安定する。その他請求項１と同様の作用を奏する。
【００１３】
請求項３のミシンの上糸張力付与装置は、請求項１又は２の発明において、前記第１の付勢力入力部は、張力調整機構の調整ビスからなることを特徴とするものである。第１の付勢力入力部を張力調整機構の調整ビスとは別に形成する場合と比較し、構成が簡単化する。その他請求項１又は２と同様の作用を奏する。
【００１４】
請求項４のミシンの上糸張力付与装置は、請求項１〜３の何れか１項の発明において、前記ベース板は上糸を案内する案内用切欠き穴を有し、この案内用切欠き穴の奥端から糸通過隙間に入る上糸を徐々にベース板側へ導く為の傾斜ガイド部を張力付与板に形成したことを特徴とするものである。それ故、案内用切欠き穴の奥端から糸通過隙間に入る上糸が、直ちにベース板側へ屈曲させられると、上糸の撚りが残存したまま糸通過隙間へ導入され、上糸の張力が乱れる原因になる。しかし、案内用切欠き穴の奥端から糸通過隙間に入る上糸が、張力付与板の傾斜ガイド部で徐々にベース板側へ導かれるため上糸の撚りが解消し易くなる。その他請求項１〜３の何れか１項と同様の作用を奏する。
【００１５】
請求項５のミシンの上糸張力付与装置は、請求項１〜４の何れか１項の発明において、前記付勢機構は、第１，第２の付勢力入力部を張力付与板の方へ付勢するコイルスプリングを有することを特徴とするものである。板バネと比較し、コイルスプリングの方が弾性力を強化する上で有利であり、弾性付勢力を調整する面でも有利である。その他請求項１〜４の何れか１項と同様の作用を奏する。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
図１、図２には、ミシンのアーム部の上面部分の上蓋２に設けた上糸張力付与装置１と、ミシンの押え足を上昇位置と下降位置とに切換える切換えレバー３とが図示されている。この張力付与装置１は、ミシンの上糸供給源としての糸駒４から天秤に至る上糸経路中に設けられている。
【００１７】
上糸張力付与装置１は、糸調子皿２１を含む主張力調整機構１０と、この主張力調整機構１０よりも糸駒４側に設けられた副張力調整機構２０とからなる。
主張力調整機構１０は、糸調子皿１１と調整ダイヤル１２とを有し、糸調子皿１１は固定側調子皿１１ａ及び可動側調子皿１１ｂと、可動側調子皿１１ｂを固定側調子皿１１ａの方へ弾性付勢するコイルバネ１３と、軸部材と、調整ダイヤル１２等を含み、調整ダイヤル１２を回動操作することでコイルバネ１３の付勢力を調整して上糸５に付与する抵抗を調整し上糸５の張力を調整できるように構成してある。調整ダイヤル１２の前面の外周部には、張力の強さを示す１，２，３・・・・９のダイアル目盛りが印されている。ダイアル目盛りが大きくなる程張力が強くなるが、ダイアル目盛り「４」は中細の太さの上糸５に適した標準的な張力となる。
【００１８】
副張力調整機構２０は、細い上糸から中細の上糸（＃９０〜＃６０の上糸）に対しては張力を殆ど付与せず、中細以上の太い上糸（＃３０程度の上糸）に対して張力を付与して、太い上糸５の張力を強化する為のものである。
この副張力調整機構２０について図２〜図８を参照して詳細に説明する。
副張力調整機構２０は、上蓋２に固定されたベース板２１と、張力付与板２２と、ベース板２１と張力付与板２２との間に挟着されて上糸通過隙間２４を形成する例えば厚さ0.2 ｍｍの金属板からなるスペーサ２３と、張力付与板２２をベース板２１の方へ弾性付勢する付勢機構２５と、この付勢機構２５に設けられた張力調整機構２６と、付勢機構２５の付勢を解除する為のリンク部材２７等を有する。
【００１９】
前記ベース板２１は、例えば厚さ約1.0 ｍｍの金属板を成形加工したもので、そのベース板本体部２１ａが上蓋２の左端部に鉛直姿勢に配設され、このベース板本体部２１ａの下端から右方へ延びる取付け部２１ｂとフランジ部２１ｃとが一体形成され、ベース板２１の前端部の上部にはフランジ部２１ｄが一体形成され、取付け部２１ｂが複数のビスにより上蓋２に固定されている。
【００２０】
ベース板２１の後部には、上糸５を案内する案内用切欠き穴２８が後端開放状に形成され、その案内用切欠き穴２８の奥端は円形状に拡大し、上糸５は案内用切欠き穴２８の奥端から上糸通過隙間２４内へ導入される。
付勢機構２５は、ベース板２１のベース板本体部２１ａとフランジ部２１ｃとに移動可能に挿通された左右方向向きの水平なロッド２９と、張力付与板２２の左側に大部分が位置するとともにロッド２９の先端部に固着された押え金具３０と、ロッド２９に外装され止め輪を介してロッド２９を右方へ弾性付勢する圧縮コイルスプリング３１等を有する（図５〜図７参照）。
【００２１】
ベース板２１の後部には、張力付与板２２とスペーサ２３とを支持する為に、水平な左右方向向きのピン３２が左方へ突出状に固定されている。張力付与板２２は、例えば厚さ0.6 ｍｍのステンレス板からなり、その前半部をなす張力付与部２２ａと、張力付与部２２ａの後端に連なる傾斜ガイド部２２ｂと、傾斜ガイド部２２ｂの後端に連なる後半支持部２２ｃとを一体形成してある。張力付与部２２ａにはロッド２９が相対移動自在に挿通するロッド穴が形成され、後半支持部２２ｃにはピン３２が相対移動自在に挿通するピン穴が形成され、張力付与板２２はピン３２とロッド２９とに左右方向へ移動自在に支持されている。
【００２２】
図５〜図７に示すように、張力付与板２２の張力付与部２２ａは、スペーサ２３と平行で且つ下半部がスペーサ２３の左面に当接し得る状態に配置され、張力付与部２２ａの上部とベース板本体部２１ａとの間には、スペーサ２３の厚さとほぼ等しい幅の糸通過隙間２４が形成されている。傾斜ガイド部２２ｂは、案内用切欠き穴２８の奥端から糸通過隙間２４に入る上糸５を徐々にベース板本体部２１ａの方へ導いて上糸５の撚りを解消する為のもので、この傾斜ガイド部２２ｂは後方程ベース板本体部２１ａから離隔するように傾斜している。
【００２３】
スペーサ２３にはピン３２が相対移動自在に挿通するピン穴と、ロッド２９が相対移動自在に挿通するロッド穴とが形成され、スペーサ２３は張力付与部２２ａの下半部とほぼ同形状をなし、ベース板２１と張力付与部２２ａとの間に配設され、ピン３２とロッド２９とに支持され、図６に示すようにスペーサ２３は、糸通過隙間２４のうちのほぼ水平な上糸経路２４ａよりも下側に位置している。
【００２４】
付勢機構２５において、押え金具３０の被ガイド部３０ａがベース板本体部２１ａの切欠き部３３に挿通されて左右方向へ移動自在に案内され、押え金具３０の上部には、左右方向向きの水平な調整ビス３４の為のネジ穴３５と、このネジ穴３５に螺合された調整ビス３４とからなる張力調整機構２６が設けられ、調整ビス３４の右端部である第１の付勢力入力部３４ａが、張力付与板２２の張力付与部２２ａのうちの糸通過隙間２４の上糸経路２４ａを形成する部分の少なくとも一部に当接している。
【００２５】
押え金具３０の下部には、第１の付勢力入力部３４ａから上糸経路２４ａとほぼ直交する方向へ（下方へ）離隔して位置し張力付与部２２ａに当接する第２の付勢力入力部３０ｂが形成され、この第２の付勢力入力部３０ｂは押え金具３０に形成したエンボス部で構成されている。前記リンク部材２７の中段部は、前後向きのピン２７ａでミシン機枠に回動自在に枢支され、リンク部材２７の下端部はミシンの押え足の位置を切換える押え上げレバー３に連動連結され、図４に示すように、押え上げレバー３を上げると、リンク部材２７が鎖線の位置に回動してロッド２９を左方へ押動させるため、張力付与板２２が付勢されなくなる。その状態で、副張力付与機構２０の制約を受けずに上糸５を掛けることができる。
【００２６】
以上の張力付与装置１、特に副張力付与機構２０の作用、効果について説明する。主張力付与機構１０の操作ダイアル１２を操作すると、ダイアル目盛りに比例的にコイルバネ１３の付勢力が増すため、上糸５にはダイアル目盛りに略比例する張力が付与される。この主張力付与機構１０の張力付与特性は、例えば図９の特性線Ａのようになっている。
【００２７】
副張力付与機構２０において、コイルスプリング３１とロッド２９により押え金具３０が右方へ付勢され、第１、第２の付勢力入力部３４ａ，３０ｂが張力付与板２２を右方へ弾性付勢し、ベース板本体部２１ａと、スペーサ２３と、張力付与板２２の張力付与部２２ａとを密着状態に保持している。ベース板２１と張力付与板２２との間にスペーサ２３を介在させて糸通過隙間２４が形成され、付勢機構２５により張力付与板２２がベース板２１の方へ弾性付勢されているため、糸通過隙間２４を通る上糸５にベース板２１と張力付与板２２とで抵抗が付加され、上糸５の太さに応じた張力が付与される。
【００２８】
そして、糸通過隙間２４の前後長を大きく形成してあるため、従来の装置に比較して上糸５に大きな抵抗を付与でき、上糸５の張力を増大させることができる。調整ビス３４により、付勢機構２５の弾性付勢力を調整することで張力付与板２２の微少弾性変形を介して上糸５の張力を調整できる。付勢力を強化すると張力が増大し、付勢力を弱めると張力が減少する。
【００２９】
例えば、調整ビス３４の突出量を第２の付勢力入力部３０ｂの突出量と略同程度に調整したものとすると、細い上糸５や中細の上糸５にはベース板２１と張力付与板２２とから抵抗が殆ど作用せず、中細以上の太さの上糸５には、太さの増大に応じた抵抗が作用するようになるので、上糸５の張力は例えば図９の特性線Ｂのようになる。特性線Ａから特性線Ｂへの張力増加分が、副張力付与機構２０で付与する張力に相当する。しかも、調整ネジ３４を微少に締め込むことで、特性線Ｂを上方へ移動させて張力を一層強くすることもできるし、その反対に調整ネジ３４を微少に緩めることで、特性線Ｂを下方へ移動させることもできる。従って、中細以上の太さの上糸５で縫製する際には、操作ダイアル１２を殆ど操作しなくとも、上糸５の張力が自動的に調整されるため縫製能率が向上する。
【００３０】
ここで、第１の付勢力入力部３４ａを張力付与板２２のうちの上糸経路２４ａを形成する部分の少なくとも一部に当接させてあるため、張力付与板２２の製作誤差等の影響を受けることなく、第１の付勢力入力部３４ａから張力付与板２２のうちの上糸経路２４ａを形成する部分の少なくとも一部に弾性付勢力が入力され、その付勢力が上糸５に伝達されるため、上糸５に作用する抵抗を安定させ、上糸５の張力を安定させることができ、張力付与板２２の製作精度の要求も緩和されて有利になる。
【００３１】
第１の付勢力入力部３４ａから上糸経路２４ａと略直交する方向へ離隔して位置する第２の付勢力入力部３０ｂを設けたので、第１，第２付勢力入力部３４ａ，３０ｂから張力付与板２２に付勢力が入力されても、張力付与板２２とベース板２１とが平行に保持され、張力付与板２２がベース板２１に対して殆ど傾くことがないから、糸通過隙間２４を通過する上糸５の位置が上下に変動しても、上糸５に作用する抵抗が変動ぜず上糸張力が安定する。
【００３２】
第１の付勢力入力部３４ａを調整ビス３４で構成したので、第１の付勢力入力部３４ａを調整ビス３４とは別に形成する場合と比較し、構成が簡単化する。ベース板２１の案内用切欠き穴２８の奥端から糸通過隙間２４に入る上糸５を徐々にベース板２１側へ導く為の傾斜ガイド部２２ｂを張力付与板２２に形成したので、上糸５の撚りが解消し易くなる。即ち、案内用切欠き穴２８の奥端から糸通過隙間２４に入る上糸５が、直ちにベース板２１側へ屈曲させられると、上糸５の撚りが残存したまま糸通過隙間２４へ導入され、上糸５の張力が乱れる原因になるが、上糸５が傾斜ガイド部２２ｂで徐々にベース板２１側へ導かれるため、上糸５の撚りが解消し易くなり、上糸５の張力が安定する。
【００３３】
前記付勢機構２５は、第１，第２の付勢力入力部３４ａ，３０ｂを張力付与板２２の方へ付勢するコイルスプリング３１を有するので、板バネと比較し、弾性力を強化する上で有利であり、弾性付勢力を微妙に調整する面でも有利である。
【００３４】
但し、ここで、前記実施形態では、張力付与板２２やベース板２１とスペーサ２３とを別部材で構成したが、スペーサ２３を張力付与板２２またはベース板２１に予め固着しておいてもよい。前記張力付与板２２やスペーサ２３の厚さは一例を示すものに過ぎず、ミシンの機種や用途に応じてそれらの厚さを適宜設定することができる。尚、前記実施形態は一例を示すものに過ぎず、各部材の形状、サイズ等については、本発明の趣旨を逸脱しない範囲において適宜変更を付加して実施できることは勿論である。
【００３５】
【発明の効果】
請求項１の発明によれば、副張力付与機構に、張力付与板をベース板の方へ弾性付勢する付勢機構を設け、この付勢機構に張力調整機構を設けたので、上糸の張力を調整することができ、それ故張力付与板やベース板の製作精度の要求が緩和されて有利になる。
【００３６】
しかも、付勢機構の第１の付勢力入力部を張力付与板のうちの糸通過隙間の上糸経路を形成する部分の少なくとも一部に当接させてあるため、張力付与板の変形や製作誤差等の影響を受けることなく、第１の付勢力入力部から張力付与板のうちの糸通過隙間の上糸経路を形成する部分の少なくとも一部に弾性付勢力が入力され、その付勢力が上糸に伝達されるため、上糸に作用する抵抗を強めるとともに安定させ、上糸の張力を強めるとともに安定させることができる。また、張力付与板の製作精度の要求が緩和されて有利になる。
【００３７】
請求項２の発明によれば、前記付勢機構は、第１の付勢力入力部から上糸経路と略直交する方向へ離隔して位置する第２の付勢力入力部を有するので、付勢機構の第１，第２付勢力入力部から張力付与板に付勢力が入力されても、張力付与板とベース板とが平行に保持され、張力付与板がベース板に対して傾くことがないから、糸通過隙間を通過する上糸の位置が変動しても、上糸に作用する抵抗が変動ぜず上糸張力が安定する。その他請求項１と同様の効果を奏する。
【００３８】
請求項３の発明によれば、前記第１の付勢力入力部は、張力調整機構の調整ビスからなるので、第１の付勢力入力部を張力調整機構の調整ビスとは別に形成する場合と比較し、構成が簡単化する。その他請求項１又は２と同様の効果を奏する。
【００３９】
請求項４の発明によれば、前記ベース板は上糸を案内する案内用切欠き穴を有し、この案内用切欠き穴の奥端から糸通過隙間に入る上糸を徐々にベース板側へ導く為の傾斜ガイド部を張力付与板に形成したので、案内用切欠き穴の奥端から糸通過隙間に入る上糸が、張力付与板の傾斜ガイド部で徐々にベース板側へ導かれるため、上糸の撚りが解消し易くなり、その結果上糸張力が安定性し易くなる。その他請求項１〜３の何れか１項と同様の効果を奏する。
【００４０】
請求項５の発明によれば、前記付勢機構は、第１，第２の付勢力入力部を張力付与板の方へ付勢するコイルスプリングを有するので、板バネと比較し、コイルスプリングの方が弾性力を強化する上で有利であり、弾性付勢力を調整する面でも有利である。その他請求項１〜４の何れか１項と同様の効果を奏する。
【図面の簡単な説明】
【図１】本発明の実施形態のミシンの張力付与装置等の斜視図である。
【図２】張力付与装置の斜視図である。
【図３】張力付与装置の副張力付与機構の平面図である。
【図４】副張力付与機構等の正面図である。
【図５】副張力付与機構の拡大平面図である。
【図６】副張力付与機構の拡大左側面図である。
【図７】副張力付与機構の拡大正面図である。
【図８】図６のVIII−VIII線断拡大図である。
【図９】張力付与装置の張力付与特性を示す線図である。
【符号の説明】
１上糸張力付与装置
４糸駒
５上糸
１０主張力付与機構
１２操作ダイアル
２０副張力付与機構
２１ベース板
２２張力付与板
２２ｂ傾斜ガイド部
２３スペーサ
２４糸通過隙間
２４ａ上糸経路
２５付勢機構
２６張力調整機構
２８切欠き案内穴
３０押え金具
３０ｂ第２の付勢力入力部
３１コイルスプリング
３４調整ビス
３４ａ第１の付勢力入力部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an upper thread tension applying device for a sewing machine that is provided in an upper thread path from an upper thread supply source to a balance and applies tension to the upper thread, and in particular, on the upstream side of the assertion force applying mechanism (thread tension mechanism). And a sub tension applying mechanism provided with a tension adjusting mechanism.
[0002]
[Prior art]
In general, the sewing machine is configured to provide tension force application mechanism including a thread tension plate in the upper thread path from the thread spool to the balance to apply tension to the upper thread. In this assertive force imparting mechanism, the tension can be adjusted by operating the adjustment dial. By the way, in general, when using a thick upper thread, in order to balance the tension with the lower thread, in order to obtain an appropriate thread tension according to the thickness of the fabric, the upper thread is compared with the case where a thin upper thread is used. The tension must be set large.
[0003]
By operating the adjustment dial of the assertion force application mechanism, the tension of the upper thread can be adjusted according to the thickness of the upper thread, but a sub-tension application mechanism is provided upstream of the assertion force application mechanism. Techniques have been proposed in which adjustment of the upper thread tension is almost omitted or the frequency of adjustment is reduced by adding resistance to the upper thread.
For example, in the upper thread tension applying device of the sewing machine described in Japanese Utility Model Laid-Open No. 5-39478, a sub-tension applying mechanism includes a base plate, a leaf spring-like presser plate, a thin spacer sandwiched between them, a base When a thread passing gap formed by a spacer is provided between the plate and the presser plate, the spacer and the presser plate are fixed to the base plate with caulking pins, and other fine measures are taken, when a thick upper thread passes. Is configured so that resistance is applied to the upper thread by the base plate and the presser plate, while almost no resistance is applied to the upper thread when the upper thread having a thin diameter of the thickness of the spacer passes.
[0004]
On the other hand, in the upper thread tension device of the sewing machine described in Japanese Utility Model Laid-Open No. 2-4574, a presser spring made of a leaf spring is stacked on the fixed plate immediately downstream of the thread tension plate, and the thread of the upper thread passes between them. A gap is formed, and the size of the thread passage gap is adjusted with an adjusting screw, so that the tension of the upper thread can be adjusted.
[0005]
[Problems to be solved by the invention]
In the upper thread tension device of the Japanese Utility Model Laid-Open No. 2-4574, the presser spring has a thin plate thickness of about 0.2 mm. Therefore, the presser spring not only needs to be made of a material having a large spring constant, but also has a thread passing gap. An extremely high dimensional accuracy is required for setting. In addition, since there is only one adjusting screw and the thread passage gap between the fixing plate and the presser spring is a gap having a wedge shape in cross section, the resistance acting on the upper thread fluctuates when the upper thread passage position fluctuates. Is difficult to stabilize.
[0006]
In the sub-tension applying mechanism disclosed in Japanese Utility Model Laid-Open No. 5-39478, although a stainless steel plate having a thickness of about 0.6 mm is applied as a presser plate, a thread passing gap is set by a thin plate spring-like presser plate. Extremely high manufacturing accuracy is required for setting. This sub-tensioning mechanism does not have a mechanism for adjusting the size of the thread passage gap or the elastic biasing force of the presser plate, so that the upper thread tension is adjusted even if there is a variation in tension due to manufacturing errors or the like. It is difficult to stabilize the needle thread tension.
[0007]
In addition, it is a structure that adds resistance to the upper thread with a thin leaf spring-like presser plate, and because the length of the thread passage gap is short, a sufficiently large resistance cannot be added to the upper thread, and the upper thread tension can be increased. There is a limit. For example, in the case of a thick upper thread, it is desirable to apply a tension of about 60 to 90 gf, but in reality, only a tension of about 20 to 40 gf could be applied. Moreover, if the yarn passing through the yarn passage gap is twisted, the tension greatly fluctuates. However, the conventional subtension applying mechanism hardly takes measures for eliminating the twist of the upper yarn.
[0008]
The purpose of the present invention is to stabilize the tension applied to the upper thread in the sub tension applying mechanism, to make the tension stronger and adjustable, and to eliminate twisting of the thread as much as possible upstream of the thread passage gap. , Etc.
[0009]
[Means for Solving the Problems]
The upper thread tension applying device of the sewing machine according to claim 1 is provided in an upper thread path from the upper thread supply source of the sewing machine to the balance, and is an upper thread tension applying device for applying tension to the upper thread. An assertion force imparting mechanism capable of applying tension and adjusting the tension, and a base provided via a spacer provided between the base plate and the tension imparting plate provided on the upper thread supply source side of the assertion force imparting mechanism. A subtension applying mechanism that forms a thread passage gap between the plate and the tension applying plate, and the subtension applying mechanism includes an urging mechanism that elastically urges the tension applying plate toward the base plate, A tension adjusting mechanism provided in the urging mechanism, and the first urging force input portion of the urging mechanism abuts at least a part of a portion of the tension applying plate that forms the upper yarn path of the yarn passing gap. It is characterized by having made it.
[0010]
In this upper thread tension applying device, while the upper thread from the thread supply source reaches the balance through the upper thread path, the upper thread is first tensioned by the sub tension applying mechanism, and then the assertive force applying mechanism. Thus, tension is applied to the upper thread. The tension applied by the main tension applying mechanism can be adjusted. In the sub-tension applying mechanism, a thread passing gap is formed between the base plate and the tension applying plate via a spacer interposed between the base plate and the tension applying plate, and the tension applying plate is Since the plate is elastically biased toward the plate, resistance is applied to the upper yarn passing through the yarn passage gap by the base plate and the tension applying plate, and tension is applied. The tension of the upper thread can be adjusted by adjusting the elastic biasing force of the biasing mechanism by the tension adjusting mechanism provided in the biasing mechanism. That is, when the urging force is strengthened, the tension increases, and when the urging force is weakened, the tension decreases.
[0011]
Here, since the first urging force input portion of the urging mechanism is in contact with at least a part of the portion of the tension applying plate that forms the upper thread path of the yarn passing gap, the deformation of the tension applying plate The elastic biasing force is input from the first biasing force input portion to at least part of the portion of the tension applying plate that forms the upper yarn path of the tension applying plate without being affected by the manufacturing error or the like. because force is transmitted to the upper thread, acts on the upper thread can be stabilized with strengthening the tension of the upper thread to stabilize with enhance resistance, also becomes advantageous are relaxed required fabrication precision Zhang the apply plate .
[0012]
The upper thread tension applying device according to a second aspect of the present invention is the sewing machine according to the first aspect, wherein the urging mechanism is located at a distance from the first urging force input portion in a direction substantially perpendicular to the upper thread path. The urging force input section is provided. Therefore, even if the urging force is input to the tension applying plate from the first and second urging force input portions of the urging mechanism, the tension applying plate and the base plate are held in parallel, and the tension applying plate is Therefore, even if the position of the upper thread passing through the thread passage gap varies, the resistance acting on the upper thread does not vary and the upper thread tension is stabilized. Other effects similar to those of the first aspect are achieved.
[0013]
The upper thread tension applying device according to a third aspect of the present invention is characterized in that, in the invention of the first or second aspect, the first urging force input portion comprises an adjusting screw of a tension adjusting mechanism. Compared with the case where the first urging force input portion is formed separately from the adjustment screw of the tension adjustment mechanism, the configuration is simplified. Other effects similar to those of the first or second aspect are achieved.
[0014]
The upper thread tension applying device of the sewing machine according to claim 4 is the invention according to any one of claims 1 to 3, wherein the base plate has a guide notch hole for guiding the upper thread, and the guide notch. An inclined guide portion is formed on the tension applying plate for gradually guiding the upper yarn entering the yarn passage gap from the back end of the hole to the base plate side. Therefore, if the upper thread that enters the thread passage gap from the back end of the guide notch hole is immediately bent to the base plate side, the upper thread twist is introduced into the thread passage gap while remaining, and the tension of the upper thread Will be disturbed. However, since the upper thread that enters the thread passage gap from the back end of the guide notch hole is gradually guided to the base plate side by the inclined guide portion of the tension applying plate, the twist of the upper thread is easily eliminated. In addition, the same effect as any one of claims 1 to 3 is exhibited.
[0015]
The upper thread tension applying device according to a fifth aspect of the present invention is the sewing machine according to any one of the first to fourth aspects, wherein the urging mechanism moves the first and second urging force input portions toward the tension applying plate. It has a coil spring to be urged. Compared to the leaf spring, the coil spring is more advantageous in strengthening the elastic force and more advantageous in terms of adjusting the elastic biasing force. Other effects similar to those of any one of claims 1 to 4 are achieved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1 and 2 illustrate an upper thread tension applying device 1 provided on an upper lid 2 of an upper surface portion of an arm portion of a sewing machine, and a switching lever 3 for switching a presser foot of the sewing machine between a raised position and a lowered position. Yes. The tension applying device 1 is provided in an upper thread path from a thread spool 4 as an upper thread supply source of a sewing machine to a balance.
[0017]
The upper thread tension applying device 1 includes an assertion force adjustment mechanism 10 including a thread tension plate 21 and a sub-tension adjustment mechanism 20 provided closer to the thread spool 4 than the assertion force adjustment mechanism 10.
The main tension adjusting mechanism 10 includes a thread tension tray 11 and an adjustment dial 12. The thread tension tray 11 includes a fixed side tension tray 11a, a movable side tension tray 11b, and a movable side tension tray 11b. Coil spring 13 that is elastically biased in the direction, shaft member, adjustment dial 12 and the like, and adjusting the biasing force of the coil spring 13 by rotating the adjustment dial 12 to adjust the resistance applied to the upper thread 5 The tension of the upper thread 5 can be adjusted. Dial scales 1, 2, 3,... 9 indicating the strength of tension are marked on the outer peripheral portion of the front surface of the adjustment dial 12. As the dial scale becomes larger, the tension becomes stronger. However, the dial scale “4” is a standard tension suitable for the upper thread 5 having a medium thickness.
[0018]
The sub-tension adjusting mechanism 20 hardly applies tension from a thin upper thread to a medium thin upper thread (# 90 to # 60 upper thread), and a medium upper thread or thicker upper thread (about # 30 upper thread). The tension is applied to the thread) and the tension of the thick upper thread 5 is strengthened.
The sub-tension adjusting mechanism 20 will be described in detail with reference to FIGS.
The sub-tension adjusting mechanism 20 is sandwiched between the base plate 21 fixed to the upper lid 2, the tension applying plate 22, and the base plate 21 and the tension applying plate 22 to form an upper thread passage gap 24. A spacer 23 made of a metal plate having a thickness of 0.2 mm, an urging mechanism 25 for elastically urging the tension applying plate 22 toward the base plate 21, a tension adjusting mechanism 26 provided on the urging mechanism 25, and an urging force A link member 27 for releasing the bias of the mechanism 25 is provided.
[0019]
The base plate 21 is formed by molding a metal plate having a thickness of about 1.0 mm, for example. The base plate main body portion 21a is disposed in a vertical posture at the left end portion of the upper lid 2, and the lower end of the base plate main body portion 21a. A mounting portion 21b and a flange portion 21c extending rightward from the base plate 21 are integrally formed. A flange portion 21d is integrally formed at the upper portion of the front end portion of the base plate 21, and the mounting portion 21b is fixed to the upper lid 2 by a plurality of screws. Yes.
[0020]
A guide notch hole 28 for guiding the upper thread 5 is formed in the rear part of the base plate 21 so that the rear end is open. The rear end of the guide notch hole 28 is enlarged in a circular shape, and the upper thread 5 is It is introduced into the upper thread passage gap 24 from the back end of the guide notch hole 28.
Most of the urging mechanism 25 is located on the left side of the tension applying plate 22 and the horizontal rod 29 in the left-right direction that is movably inserted through the base plate main body portion 21 a and the flange portion 21 c of the base plate 21. There are a presser fitting 30 fixed to the tip of the rod 29, a compression coil spring 31 etc. which is externally attached to the rod 29 and elastically biases the rod 29 rightward via a retaining ring (see FIGS. 5 to 7).
[0021]
In order to support the tension applying plate 22 and the spacer 23, a horizontal left and right pin 32 is fixed to the rear portion of the base plate 21 so as to protrude leftward. The tension applying plate 22 is made of, for example, a stainless steel plate having a thickness of 0.6 mm, the tension applying portion 22a forming the front half thereof, the inclined guide portion 22b connected to the rear end of the tension applying portion 22a, and the rear end of the inclined guide portion 22b. The latter half support part 22c connected to is integrally formed. A rod hole through which the rod 29 is inserted in a relatively movable manner is formed in the tension applying portion 22a, a pin hole through which the pin 32 is inserted in a relatively movable manner is formed in the latter half support portion 22c, and the tension applying plate 22 is connected to the pin 32. The rod 29 is supported so as to be movable in the left-right direction.
[0022]
As shown in FIGS. 5 to 7, the tension applying portion 22 a of the tension applying plate 22 is disposed in a state parallel to the spacer 23 and in a state where the lower half can contact the left surface of the spacer 23, and the upper portion of the tension applying portion 22 a. A thread passage gap 24 having a width substantially equal to the thickness of the spacer 23 is formed between the main body 21a and the base plate main body 21a. The inclined guide portion 22b is used to gradually guide the upper thread 5 entering the yarn passage gap 24 from the back end of the guide notch hole 28 toward the base plate main body portion 21a to eliminate twisting of the upper thread 5. The inclined guide portion 22b is inclined so as to be separated from the base plate main body portion 21a toward the rear.
[0023]
The spacer 23 is formed with a pin hole through which the pin 32 is inserted so as to be relatively movable and a rod hole through which the rod 29 is inserted so as to be relatively movable. The spacer 23 has substantially the same shape as the lower half of the tension applying portion 22a. The spacer 23 is disposed between the base plate 21 and the tension applying portion 22a and supported by the pin 32 and the rod 29, and the spacer 23 is a substantially horizontal upper thread path in the thread passage gap 24 as shown in FIG. It is located below 24a.
[0024]
In the urging mechanism 25, the guided portion 30 a of the presser fitting 30 is inserted into the notch 33 of the base plate main body 21 a and is guided to be movable in the left-right direction. A tension adjusting mechanism 26 including a screw hole 35 for the horizontal adjusting screw 34 and an adjusting screw 34 screwed into the screw hole 35 is provided, and a first biasing force input which is a right end portion of the adjusting screw 34 is provided. The portion 34 a is in contact with at least a part of the portion of the tension applying portion 22 a of the tension applying plate 22 that forms the upper yarn path 24 a of the yarn passing gap 24 .
[0025]
A second urging force input portion that is located at a lower portion of the presser fitting 30 so as to be spaced apart (downward) from the first urging force input portion 34a in a direction substantially perpendicular to the upper thread path 24a and that contacts the tension applying portion 22a. 30 b is formed, and the second urging force input portion 30 b is constituted by an embossed portion formed on the presser fitting 30. The middle part of the link member 27 is pivotally supported on the sewing machine frame by a forward and backward pin 27a, and the lower end of the link member 27 is interlocked with the presser lifting lever 3 for switching the position of the presser foot of the sewing machine. As shown in FIG. 4, when the presser foot lifting lever 3 is raised, the link member 27 rotates to the position of the chain line and pushes the rod 29 leftward, so that the tension applying plate 22 is not biased. In this state, the upper thread 5 can be hung without being restricted by the sub tension applying mechanism 20.
[0026]
The operation and effect of the tension applying device 1 described above, particularly the sub tension applying mechanism 20, will be described. When the operation dial 12 of the main tension applying mechanism 10 is operated, the urging force of the coil spring 13 increases in proportion to the dial scale, so that a tension substantially proportional to the dial scale is applied to the upper thread 5. The tension applying characteristic of the assertive force applying mechanism 10 is, for example, as shown by a characteristic line A in FIG.
[0027]
In the sub-tension applying mechanism 20, the presser fitting 30 is urged to the right by the coil spring 31 and the rod 29, and the first and second urging force input portions 34a and 30b elastically urge the tension applying plate 22 to the right. In addition, the base plate body 21a, the spacer 23, and the tension applying portion 22a of the tension applying plate 22 are held in close contact. Since the spacer 23 is interposed between the base plate 21 and the tension applying plate 22 to form a thread passage gap 24, and the tension applying plate 22 is elastically biased toward the base plate 21 by the biasing mechanism 25. Resistance is applied to the upper thread 5 passing through the thread passage gap 24 by the base plate 21 and the tension applying plate 22, and a tension according to the thickness of the upper thread 5 is applied.
[0028]
And since the front-rear length of the thread passage gap 24 is formed large, a greater resistance can be applied to the upper thread 5 than in the conventional device, and the tension of the upper thread 5 can be increased. By adjusting the elastic urging force of the urging mechanism 25 with the adjusting screw 34, the tension of the upper thread 5 can be adjusted through the slight elastic deformation of the tension applying plate 22. When the urging force is strengthened, the tension increases, and when the urging force is weakened, the tension decreases.
[0029]
For example, if the protruding amount of the adjusting screw 34 is adjusted to be approximately the same as the protruding amount of the second urging force input portion 30b, the thin upper thread 5 and the medium upper thread 5 are given tension to the base plate 21. Resistance hardly acts from the plate 22, and resistance according to the increase in thickness is exerted on the upper thread 5 having a thickness of medium or thinner, so that the tension of the upper thread 5 is, for example, as shown in FIG. It looks like a characteristic line B. The increase in tension from the characteristic line A to the characteristic line B corresponds to the tension applied by the sub-tension applying mechanism 20. In addition, by slightly tightening the adjusting screw 34, the characteristic line B can be moved upward to further increase the tension, and conversely, by slightly loosening the adjusting screw 34, the characteristic line B can be lowered. It can also be moved to. Accordingly, when sewing with the upper thread 5 having a thickness of medium or larger, the tension of the upper thread 5 is automatically adjusted without almost operating the operation dial 12, so that the sewing efficiency is improved.
[0030]
Here, since the first urging force input portion 34a is brought into contact with at least a part of the portion of the tension applying plate 22 that forms the upper thread path 24a , the influence of the manufacturing error of the tension applying plate 22 is affected. Without receiving, an elastic biasing force is input from the first biasing force input portion 34 a to at least a part of the portion of the tension applying plate 22 forming the upper thread path 24 a, and the biasing force is transmitted to the upper thread 5. Therefore, the resistance acting on the upper thread 5 can be stabilized, the tension of the upper thread 5 can be stabilized, and the requirement for the production accuracy of the tension applying plate 22 is eased, which is advantageous.
[0031]
It is provided with the second urging force input portion 30b positioned spaced apart in a direction substantially perpendicular to the upper thread path 24a from the first urging force input portion 34a, first, second biasing force input section 3 4a, 30b Even if an urging force is input from the tension applying plate 22 to the tension applying plate 22, the tension applying plate 22 and the base plate 21 are held in parallel, and the tension applying plate 22 hardly tilts with respect to the base plate 21. Even if the position of the upper thread 5 passing through 24 fluctuates up and down, the resistance acting on the upper thread 5 does not fluctuate and the upper thread tension is stabilized.
[0032]
Since the first urging force input portion 34a is configured by the adjustment screw 34, the configuration is simplified as compared with the case where the first urging force input portion 34a is formed separately from the adjustment screw 34. Since the inclined guide portion 22b for gradually guiding the upper thread 5 entering the thread passage gap 24 from the back end of the guide notch hole 28 of the base plate 21 to the base plate 21 side is formed on the tension applying plate 22, the upper thread 5 becomes easy to cancel. That is, when the upper thread 5 entering the thread passage gap 24 from the back end of the guide notch hole 28 is immediately bent to the base plate 21 side, the twist of the upper thread 5 is introduced into the thread passage gap 24 while remaining. Although the tension of the upper thread 5 is disturbed, since the upper thread 5 is gradually guided to the base plate 21 side by the inclined guide portion 22b, the twist of the upper thread 5 is easily eliminated, and the tension of the upper thread 5 is reduced. Stabilize.
[0033]
The urging mechanism 25 includes a coil spring 31 that urges the first and second urging force input portions 34a and 30b toward the tension applying plate 22. Therefore, the urging mechanism 25 has a higher elastic force than the plate spring. This is also advantageous in terms of finely adjusting the elastic biasing force.
[0034]
However, in this embodiment, the tension applying plate 22 or the base plate 21 and the spacer 23 are configured as separate members. However, the spacer 23 may be fixed to the tension applying plate 22 or the base plate 21 in advance. . The thicknesses of the tension applying plate 22 and the spacer 23 are merely examples, and the thicknesses can be appropriately set according to the machine type and application of the sewing machine. In addition, the said embodiment is only an example and it cannot be overemphasized that it can add and change suitably about the shape, size, etc. of each member in the range which does not deviate from the meaning of this invention.
[0035]
【The invention's effect】
According to the first aspect of the present invention, the subtension applying mechanism is provided with a biasing mechanism that elastically biases the tension applying plate toward the base plate, and the tension adjusting mechanism is provided in the biasing mechanism. The tension can be adjusted, and therefore the requirements for the production accuracy of the tension applying plate and the base plate are relaxed, which is advantageous.
[0036]
Moreover, since the first urging force input portion of the urging mechanism is in contact with at least a part of the portion of the tension applying plate that forms the upper thread path of the yarn passing gap, the tension applying plate is deformed or manufactured. Without being affected by an error or the like, an elastic urging force is input from the first urging force input portion to at least a part of the portion of the tension applying plate that forms the upper yarn path of the yarn passing gap, and the urging force is Since it is transmitted to the upper thread, the resistance acting on the upper thread can be increased and stabilized, and the tension of the upper thread can be increased and stabilized. In addition, the requirement for manufacturing accuracy of the tension applying plate is relaxed, which is advantageous.
[0037]
According to the invention of claim 2, since the urging mechanism has the second urging force input portion that is located away from the first urging force input portion in a direction substantially orthogonal to the upper thread path, Even if urging force is input to the tension applying plate from the first and second urging force input portions of the mechanism, the tension applying plate and the base plate are held in parallel, and the tension applying plate does not tilt with respect to the base plate. Therefore, even if the position of the upper thread passing through the thread passage gap varies, the resistance acting on the upper thread does not vary and the upper thread tension is stabilized. Other effects similar to those of the first aspect are obtained.
[0038]
According to the invention of claim 3, since the first urging force input part is composed of an adjustment screw of the tension adjustment mechanism, the first urging force input part is formed separately from the adjustment screw of the tension adjustment mechanism. Compare and simplify the configuration. Other effects similar to those of the first or second aspect are achieved.
[0039]
According to a fourth aspect of the present invention, the base plate has a guide notch hole for guiding the upper thread, and the upper thread entering the thread passage clearance from the back end of the guide notch hole is gradually moved toward the base plate. Since the inclined guide part for guiding to the tension is formed on the tension applying plate, the upper thread entering the thread passage gap from the back end of the guide notch hole is gradually guided to the base plate side by the inclined guide part of the tension applying plate. Therefore, the twist of the upper thread is easily eliminated, and as a result, the upper thread tension is easily stabilized. In addition, the same effects as any one of claims 1 to 3 can be obtained.
[0040]
According to the invention of claim 5, the urging mechanism has a coil spring that urges the first and second urging force input portions toward the tension applying plate. This is advantageous in strengthening the elastic force, and is also advantageous in adjusting the elastic biasing force. In addition, the same effects as any one of claims 1 to 4 can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view of a tension applying device for a sewing machine according to an embodiment of the present invention.
FIG. 2 is a perspective view of a tension applying device.
FIG. 3 is a plan view of a sub tension applying mechanism of the tension applying device.
FIG. 4 is a front view of a subtension applying mechanism and the like.
FIG. 5 is an enlarged plan view of a sub-tension applying mechanism.
FIG. 6 is an enlarged left side view of the sub-tension applying mechanism.
FIG. 7 is an enlarged front view of a sub-tension applying mechanism.
FIG. 8 is an enlarged view taken along line VIII-VIII in FIG. 6;
FIG. 9 is a diagram showing tension application characteristics of the tension application device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper thread tension imparting device 4 Yarn piece 5 Upper thread 10 Main tension imparting mechanism 12 Operation dial 20 Sub tension imparting mechanism 21 Base plate 22 Tension imparting plate 22b Inclined guide portion 23 Spacer 24 Thread passage gap 24a Upper thread path 25 Energizing mechanism 26 Tension adjusting mechanism 28 Notch guide hole 30 Presser fitting 30b Second urging force input portion 31 Coil spring 34 Adjustment screw 34a First urging force input portion

Claims

In the upper thread tension applying device that is provided in the upper thread path from the upper thread supply source of the sewing machine to the balance and applies tension to the upper thread,
An assertion force imparting mechanism that can apply tension to the upper thread and adjust the tension, and a spacer provided on the upper thread supply source side of the assertion force imparting mechanism and interposed between the base plate and the tension imparting plate A subtension applying mechanism that forms a thread passage gap between the base plate and the tension applying plate ,
The sub-tension applying mechanism is provided with an urging mechanism that elastically urges the tension applying plate toward the base plate, and a tension adjusting mechanism provided in the urging mechanism,
The upper thread tension application of the sewing machine characterized in that the first urging force input portion of the urging mechanism is brought into contact with at least a part of a portion of the tension application plate that forms the upper thread path of the thread passage gap. apparatus.

2. The sewing machine according to claim 1, wherein the urging mechanism includes a second urging force input portion that is positioned away from the first urging force input portion in a direction substantially orthogonal to the upper thread path. Upper thread tension applying device.

The upper thread tension applying device of the sewing machine according to claim 1 or 2, wherein the first urging force input portion is an adjustment screw of a tension adjustment mechanism.

The base plate has a guide notch hole for guiding the upper thread, and the inclined guide part for gradually guiding the upper thread entering the thread passage gap from the back end of the guide notch hole to the base plate side is tensioned. The upper thread tension applying device according to any one of claims 1 to 3, wherein the upper thread tension applying device is formed on an applying plate.

5. The sewing machine according to claim 1, wherein the urging mechanism includes a coil spring that urges the first and second urging force input portions toward the tension applying plate. 6. Upper thread tension applying device.