【０００１】
【発明の属する技術分野】
本発明は、段ボールの折り曲げ位置に設ける罫線構造に係り、罫線を正確に折り込むことができる段ボールの罫線構造及び罫線成形装置並びに罫線成形方法に関する。
【０００２】
【従来の技術】
段ボール紙で箱を製造するには、通常次のように行われる。
【０００３】
はじめに、段ボール紙から、図１に示すブランクＰを形成する。すなわち、図１の形状に打ち抜き、罫線Ｐ１、Ｐ２を形成する。これらの罫線は、折り曲げ時に内側となる面から線状に押し潰してなるものである。このブランクＰを図中上から下へ移送しながら、縦罫線Ｐ２の中から第２罫線Ｐ２ａ及び、第４罫線Ｐ２ｂを折り曲げ、のり代片Ｐ３を接着する（図２参照）。通常、箱メーカーでは、この接着直後の未だ扁平な状態が箱の完成品とされ、図２の状態で販売される。
【０００４】
この箱の製造において、図２の符号ａ，ｂ間に、次のような不良品が発生することがある。例えば、符号ａの間隔が符号ｂの間隔よりも広がる状態で、所謂フィッシュテール現象といわれる不良品である。また、符号ａ，ｂ間の間隔が正常より大きすぎたり、小さすぎる不良品もある。
【０００５】
段ボール箱において、通常、段ボール紙の中芯Ｑ１の段目は、積み重ね荷重に耐えるようにするため、図１に示すように、縦方向に設定される。縦罫線Ｐ２は、この製造工程において折り曲げられる折り曲げ罫線であり、その方向は中芯Ｑ１の段目と略一致している。このように中芯Ｑ１の段目と略一致している縦罫線Ｐ２に沿って折り曲げる場合、その折り曲げ線は不安定になりやすく、前記のような不良品の発生が多い。
【０００６】
不良品が発生する理由は、次のように考えられる。すなわち、図３に示す如く、縦罫線Ｐ２を押刃１０で押圧形成する際に、中芯Ｑ１の山部や谷部のどの位置に押刃１０が当たるかは、全く特定することができない。押刃１０が中芯Ｑ１の山部や谷部の中央に当たり、縦罫線Ｐ２を介した左右両側の中芯Ｑ１が等しい状態にある場合は、縦罫線Ｐ２に沿ってある程度正確に折り込むことができる。ところが、押刃１０が中芯Ｑ１の山部や谷部の中央位置からずれていると、縦罫線Ｐ２を介して左右の中芯Ｑ１の潰れやすさが非対称となり、これにより、折畳み時に形成される折り筋が、もとの罫線の位置からずれてしまうものである。
【０００７】
すなわち、縦罫線Ｐ２を折り込む際に、図４（イ）の如く、９０°程度までは縦罫線Ｐ２に沿って折ることができたとしても、同図（ロ）の如く、９０°を越えて折り込んだときに、縦罫線Ｐ２を介して対向する中芯Ｑ１が互いに潰し合い、これらの中芯Ｑ１が折り曲げ時の抵抗となる。この場合、折り込む方向は抵抗の少ない方向へ偏る傾向があり、縦罫線Ｐ２を介して対向する中芯Ｑ１が非対称の状態にある場合は、縦罫線Ｐ２から折り目がずれて正確に折り込むことが困難になる。
【０００８】
このように、縦罫線Ｐ２の折り目が中芯Ｑ１の抵抗によってずれることで、前述のような不良品が発生する。特に、折り曲げ工程を捻れベルト等により行なうので、折り曲げ時に前方から次第に折り曲げていくことになる。このため折り筋が次第にずれて斜めになり、前記フィッシュテール現象が発生しやすい。また、外側からフラップを押しながら曲げるので、過剰な折り込みも起こりやすい。
【０００９】
この対策として、当発明者は、この本罫線部から直角方向に延びる短直線を、本罫線部に隣接するように多数並べ、本罫線部と共に押し潰し形成する隣接部を設けた折り曲げ罫線を提案している（特許文献１）。更に、隣接部を本罫線部の全長の一部又は全体において左右非対称に形成する構成、例えば、折畳み時の折り筋がずれやすい方向と反対側のみに隣接部を設ける構成も提案している（特許文献２）。
【００１０】
これらの折り曲げ罫線によると、本罫線部を折り筋として折り曲げ、段ボール紙の対向する中芯が互いに衝突して潰されるとき、隣接部により中芯の平均的強度は低下させられているので、容易に押し潰される。更に、隣接部を左右非対称に設けると、折畳み時の折り筋の特定方向の位置ずれ、曲がりを効果的に防止することができる。
【００１１】
しかし、隣接部を過剰に設ければ、当然、本罫線部が不明瞭となって折り筋がずれてしまう。このため、隣接部の量は必要最小限としなければならない。また、折畳み時の折り筋がずれやすい方向と反対側のみに隣接部を設けるには、その設ける位置にも配慮が必要である。この隣接部の最適形態は、段ボール紙の性質、箱の形状、寸法、製箱機の特性等により定まるものであり、予め知ることは困難である。
【００１２】
このように、段ボールにとって、この中芯が罫線の折り込み精度を妨げる重大な原因になっていた。このため、更に特許文献３に記載の罫線構造も提案されている。
【００１３】
特許文献３に記載された罫線構造は、段ボールに押圧形成する罫線の両脇に、罫線に対して傾斜した補助罫線を左右対称形状に押圧形成した罫線構造である。
【００１４】
【特許文献１】
特開平９−７０９０５号公報
【特許文献２】
特許第２８９９７９７号公報
【特許文献３】
特許第３１６５６５９号公報
【００１５】
【発明が解決しようとする課題】
ところが、特許文献３では、箱体強度を保つ中芯が、広い範囲で補助罫線によって潰されることになるので、縦罫線周辺の強度が著しく低下するのみならず、組みたて後の箱体の強度が低下する虞もある。
【００１６】
また、特許文献３のように、罫線に対して傾斜した補助罫線であっても、補助罫線を左右対称形状に設けると、補助罫線を設けていない部分は、縦罫線を介して中芯が相対向する位置に残り、これらの中芯が折り込む際の抵抗になる。また、これらの中芯が縦罫線を介して非対称の状態にあると、抵抗の少ない方へと傾きやすくなり、前述の如き、折り込み位置にずれが生じる虞は完全に解消されていない。
【００１７】
更に、縦罫線を折り込む際の中芯の抵抗を極力少なくするために、縦罫線に沿った両側を広く押し潰した場合には、縦罫線が不明瞭となり、縦罫線に沿って折り込む際に、折り込み基点となる折り筋の応力が分散して縦罫線以外に折り筋がずれる虞がある。この結果、折り始めから基点となる折り筋が定まらず、縦罫線に沿って正確に折り込むことができなくなる。
【００１８】
そこで、本発明は上述の課題を解消すべく創出されたもので、中芯の段目に沿った縦罫線を極めて正確に折り込むことが可能になり、精度の高い段ボール箱を製造できる段ボールの罫線構造及び罫線成形装置並びに罫線成形方法の提供を目的とする。
【００１９】
【課題を解決するための手段】
上述の目的を達成するため、本発明の第１の手段は、段ボールに押圧形成され、段ボール中芯Ｑ１の段目に沿って設けられる罫線構造において、段目に沿った主罫線１の左右両側に、断面略波形状に凹む隣接凹部２を交互に押圧形成すると共に、該隣接凹部２に隣接し押圧されずに残った部分で嵌合部３を設け、主罫線１に沿って折り込んだときに、嵌合部３が対向する隣接凹部２内に嵌合するように設けたことにある。
【００２０】
第２の手段の隣接凹部２は、前記主罫線１に対して直角方向に延長され、該主罫線１に接し主罫線１と略同じ深さに形成した位置から離れるほど次第に浅くなるように形成すると共に、隣接凹部２の底部の幅が嵌合部３の頂部の幅よりも広くなるように形成する。
【００２１】
第３の手段の罫線成形装置は、段ボールＱを押圧し、段ボールＱ中芯Ｑ１の段目に沿って罫線を設ける罫線の成形装置である。この装置において、段目に沿った主罫線１を押圧形成する押刃１０を設け、該押刃１０の左右両側に、断面略波形状に凹む隣接凹部２を形成する押型１１を交互に設け、該押型１１により、主罫線１から離れるほど次第に浅くなる隣接凹部２を形成すると共に、隣接凹部２の底部の幅が隣接凹部２に対向する嵌合部３の頂部の幅よりも広くなるように形成する。
【００２２】
第４の手段の罫線成形方法は、段ボールＱを押圧形成し、段ボールＱ中芯Ｑ１の段目に沿って罫線を設ける罫線の成形方法である。この成形方法において、段ボールＱ表面の一部を加湿し、該加湿部分に、段目に沿った主罫線１と、該主罫線１の左右両側に交互に設けられ、断面略波形状に凹む隣接凹部２とを同時に押圧成形し、成形後加湿部分を乾燥させて主罫線１と隣接凹部２との形状を保つようにすることにある。
【００２３】
本発明によると、主罫線１の左右両側に、断面略波形状に凹む隣接凹部２を交互に押圧形成することで、９０°を越えて主罫線１を折り込むと、主罫線１を介して隣接凹部２に対向する嵌合部３が隣接凹部２に嵌合する。したがって、中芯Ｑ１の抵抗を受けずに主罫線１を正確に折り畳むことができ、隣接凹部２に嵌合した嵌合部３は、主罫線１の周囲の強度を保つものである。また、主罫線１に沿って嵌合部３が交互に配設されているので、主罫線１折り始めには、この主罫線１と嵌合部３との接点に折り曲げ応力が集中し、折り曲げ位置のずれを防止する。
【００２４】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態を説明する。図５乃至図１４には、本発明の罫線構造又は罫線成形装置の実施例を示しており、段ボールＱの中芯Ｑ１の段目に沿った主罫線１の左右両側に、断面略波形状に凹む隣接凹部２を交互に形成するものである。該隣接凹部２に隣接する部分には押圧されずに残った部分で嵌合部３を設けている。そして、主罫線１に沿って折り込んだときに、嵌合部３が対向する隣接凹部２内に嵌合するように設ける（図１４参照）。図示の主罫線１及び隣接凹部２は、段ボール箱を形成するブランクＰを打ち抜くと同時に押圧形成されており、特に主罫線１は、図１に示す如く段ボール箱の縦罫線Ｐ２として形成している。
【００２５】
隣接凹部２は、前記主罫線１に対して直角方向に延長されている。また、主罫線１に接した位置では主罫線１と略同じ深さに形成し、この位置から離れるほど次第に浅くなるように形成する（図７、図１０、図１３参照）。すなわち、主罫線１から離れるほど潰されないので、主罫線１周辺の強度が維持され、主罫線１に近付く程、主罫線１の周辺が深く押圧されて効果的に弱められることになる。尚、隣接凹部２の傾斜角度や長さは図示例に限定されるものではなく、設計変更は任意である。
【００２６】
隣接凹部２の底部の幅を嵌合部３の頂部の幅よりも広くなるように形成している（図６、図９、図１２参照）。この構成により、主罫線１に沿って折り込んだときに、嵌合部３が隣接凹部２内の奥に接するまで折り畳むことが可能になる。また、隣接凹部２の中に嵌合部３が嵌入すると、隣接凹部２で弱められた主罫線１の周辺強度を補強する。図示例では、隣接凹部２の底部の幅を嵌合部３の頂部の幅よりも明らかに広く形成しているが、これらの長さは任意に変更できるもので、隣接凹部２の底部の幅と嵌合部３の頂部の幅とが僅かに異なる程度に設定することも可能である。
【００２７】
本発明の罫線成形装置は、段目に沿った主罫線１を押圧形成する押刃１０と、該主罫線１の左右両側に、断面略波形状に凹む隣接凹部２を交互に形成する押型１１とを使用する（図５、図８、図１１参照）。押刃１０は、支持台１３に固定されており、この押刃１０の長手方向に沿った左右に押型１１を交互に装着する。該押型１１は、主罫線１から離れるほど次第に浅くなる隣接凹部２を形成すると共に、隣接凹部２の底部の幅が嵌合部３の頂部の幅よりも広くなるように設定している。
【００２８】
図５に示す罫線成形装置の押型１１は、押刃１０の先端から斜め上方に延長される押圧面１１Ａを有している。この装置で段ボールＱを押圧すると、図６に示す如く隣接凹部２は、断面略波形状に凹設され、図７に示す如く隣接凹部２は、主罫線１から離れるに連れて次第に浅くなるように形成される。
【００２９】
図８に示す罫線成形装置の押型１１は、当て板１４の上面に成形板１２を接着し、前記押型１１に対向するように配したものである。このとき、押刃１０の先端が押型１１より下方に突出するように設定している。この状態で、当て板１４が上昇すると、主罫線１が隣接凹部２よりも深く、下方に突出した状態に形成される（図１０参照）。このような主罫線１を形成することで、主罫線１に沿って、折り込み時の応力をより集中させることが可能になるので、折り込み作業を更に容易ならしめることができる。尚、押型１１及び成形板１２の材質はプラスチックが好適であるが、コルク等の比較的硬質の弾性材に変更してもよい。図示の当て板１４は、段ボールＱを打ち抜いてブランクＰを形成する抜き板が使用され、ブランクＰ形成時に主罫線１と隣接凹部２とが同時に形成される。この装置で段ボールＱを押圧すると、図９に示す如く隣接凹部２は、断面略波形状に凹設され、図１０に示す如く隣接凹部２は、主罫線１から離れるに連れて次第に浅くなるように形成される。
【００３０】
図１１に示す罫線成形装置の押型１１は、隣接凹部２の底部を略水平に押圧する押圧面１１Ｂと、この押圧面１１Ｂから斜め上方に延長される押圧面１１Ａとを有している。また、押刃１０の先端が押型１１より下方に突出するように設定している。この押型１１では、図１２に示す如く隣接凹部２の断面が角張った略波形状に凹設されるように設定している。したがって、該押型１１で押圧された隣接凹部２と、押型１１で押圧されない嵌合部３との概略平面図は、図１４に示すようになる。さらに、図１３に示す如く隣接凹部２の底部は略水平に形成され、この底部から離れるに連れて次第に浅くなるように形成される。また、主罫線１は隣接凹部２よりも深く形成され、図８で用いた成形板１２を使用せずに、主罫線１の折り込み作業を容易ならしめることができる。
【００３１】
主罫線１及び隣接凹部２を成形する方法として、予め段ボールＱを加湿する方法がある。すなわち、段ボールＱ表面の一部を加湿し、該加湿部分に、段目に沿った主罫線１と、該主罫線１の左右両側に交互に設けられ、断面略波形状に凹む隣接凹部２とを押圧成形する。加湿部分は、主罫線１と隣接凹部２とを押圧成形する部分にできるだけ限定することが好ましい。また、加湿方法は、湯や水を霧状にして吹付ける手段や、刷毛などで塗布する手段など任意の選択が可能である。
【００３２】
更に、段ボール箱を成形する場合には、ブランクＰ成形前に、段ボールＱの一部を加湿し、この段ボールＱからブランクＰを打ち抜くと同時に、該加湿部分に、主罫線１と隣接凹部２とを同時に形成する。
【００３３】
主罫線１と隣接凹部２とを成形した後は、加湿部分を乾燥させて主罫線１と隣接凹部２との形状を保存する。このように、段ボールＱを加湿することにより、主罫線１及び隣接凹部２を鮮明に押圧形成することができる。しかも乾燥後は、これらの形状を長期間保つことが可能になる。
【００３４】
【発明の効果】
本発明の上記構成により当初の目的を達成した。すなわち、段ボールＱの中芯Ｑ１の段目に沿った主罫線１の左右両側に、断面略波形状に凹む隣接凹部２を交互に押圧形成すると共に、該隣接凹部２に隣接し押圧されずに残った部分で嵌合部３を設け、主罫線１に沿って折り込んだときに、嵌合部３が対向する隣接凹部２内に嵌合するように設けたことにより、中芯Ｑ１の抵抗を受けずに、折り重なる位置まで主罫線１を正確に折り畳むことができる。
【００３５】
したがって本発明によると、図２に示す如く、ブランクＰの縦罫線Ｐ１ａを折り畳み、のり代片Ｐ３を接着する際に、図示の符号ａ、ｂ間は常に正確な間隔に保たれ、従来のように符号ａ、ｂ間が狂う不具合は一切解消された。この結果、極めて精度の高いダンボール箱を提供することができる。
【００３６】
また、隣接凹部２は、前記主罫線１に対して直角方向に延長され、該主罫線１に接し主罫線１と略同じ深さに形成した位置から離れるほど次第に浅くなるように形成しているので、隣接凹部２を設ける主罫線１周辺の強度は、主罫線１に近付く程効果的に弱まり、また、主罫線１から離れる程、もとの強度が維持される。この結果、主罫線１の折り込み精度を高めながら、従来のような主罫線１周辺の強度を著しく弱める不都合も解消された。
【００３７】
更に、隣接凹部２の底部の幅が嵌合部３の頂部の幅よりも広くなるように形成しているので、嵌合部３が隣接凹部２の奥まで嵌合する。この状態により、主罫線１近傍の嵌合部分の強度を高めると共に、組み立て後の段ボール箱の強度を高める効果もある。
【００３８】
一方、本発明罫線成形装置によると、段目に沿った主罫線１を押圧形成する押刃１０を設け、該押刃１０の左右両側に、断面略波形状に凹む隣接凹部２を形成する押型１１を交互に設け、該押型１１により、主罫線１から離れるほど次第に浅くなる隣接凹部２を形成すると共に、隣接凹部２の底部の幅が隣接凹部２に対向する嵌合部３の頂部の幅よりも広くなるように形成しているので、主罫線１や隣接凹部２を簡単に形成することができる。
【００３９】
また、本発明の罫線成形方法では、段ボール表面の一部を加湿し、該加湿部分に、主罫線１と隣接凹部２とを押圧成形し、成形後加湿部分を乾燥させて主罫線１と隣接凹部２との形状を保存するので、これら主罫線１及び隣接凹部２を鮮明に押圧形成することができ、加湿部分が乾燥した後は、これらの形状が安定し、長期間保たれる効果がある。
【００４０】
このように、本発明によると、段ボールの罫線を極めて正確に折り込むことが可能になり、精度の高い段ボール箱を提供できるなどといった有益な種々の効果を奏するものである。
【図面の簡単な説明】
【図１】段ボール箱を形成するブランクを示す平面図である。
【図２】ブランクを折り畳んでのり代を接着する状態を示す平面図である。
【図３】段ボールの中芯と押刃との位置関係を示す概念図である。
【図４】段ボールを主罫線から折り込む状態を示し、（イ）は９０°まで折り込んだ状態を示し、（ロ）は９０°を越えて折り込んだ状態を示す概念図である。
【図５】本発明罫線成形装置の一実施例を示し、（イ）は押圧前、（ロ）は押圧時を示す要部断面図である。
【図６】図５（ロ）に示す矢視Ａ−Ａ線断面図である。
【図７】図５に示す罫線成形装置で形成される主罫線及び隣接凹部を示す端面図である。
【図８】本発明の罫線成形装置の他の実施例を示し、（イ）は押圧前、（ロ）は押圧時を示す要部断面図である。
【図９】図８（ロ）に示す矢視Ａ−Ａ 線断面図である。
【図１０】図８に示す罫線成形装置で形成される主罫線及び隣接凹部を示す端面図である。
【図１１】本発明罫線成形装置の他の実施例を示し、（イ）は押圧前、（ロ）は押圧時を示す要部断面図である。
【図１２】図１１（ロ）に示す矢視Ａ−Ａ 線断面図である。
【図１３】図１１に示す罫線成形装置で形成される主罫線及び隣接凹部を示す端面図である。
【図１４】図１１に示す罫線成形装置で形成される隣接凹部及び嵌合部を示す要部概略平面図である。
【符号の説明】
Ｐ ブランク Ｐ１ 横罫線
Ｐ２ 縦罫線
Ｐ３ のり代片
Ｑ 段ボール Ｑ１ 中芯
１ 主罫線
２ 隣接凹部
３ 嵌合部
１０ 押刃
１１ 押型 １１Ａ 押圧面
１１Ｂ 押圧面
１２ 成形板
１３ 支持台
１４ 当て板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ruled line structure provided at a folding position of a cardboard, and relates to a ruled line structure, a ruled line forming apparatus, and a ruled line forming method capable of accurately folding a ruled line.
[0002]
[Prior art]
In order to manufacture a box with corrugated paper, it is normally performed as follows.
[0003]
First, the blank P shown in FIG. 1 is formed from corrugated paper. That is, it is punched into the shape of FIG. 1 to form ruled lines P1 and P2. These ruled lines are formed by crushing in a linear shape from the inner surface when bent. While the blank P is transferred from the top to the bottom in the figure, the second ruled line P2a and the fourth ruled line P2b are bent from the vertical ruled line P2, and the glue piece P3 is bonded (see FIG. 2). Usually, in the box maker, the flat state just after the bonding is regarded as a finished product of the box and sold in the state shown in FIG.
[0004]
In the manufacture of this box, the following defective products may occur between the symbols a and b in FIG. For example, in a state where the interval of the symbol a is wider than the interval of the symbol b, it is a defective product called a so-called fishtail phenomenon. In addition, there is a defective product in which the interval between the symbols a and b is too large or too small than normal.
[0005]
In the cardboard box, the core of the corrugated paper core Q1 is usually set in the vertical direction as shown in FIG. 1 in order to withstand the stacking load. The vertical ruled line P2 is a bent ruled line that is bent in this manufacturing process, and its direction substantially coincides with the step of the center core Q1. In this way, when folding along the vertical ruled line P2 that is substantially coincident with the step of the center core Q1, the folding line tends to become unstable, and the above-mentioned defective products are often generated.
[0006]
The reason why defective products are generated is considered as follows. That is, as shown in FIG. 3, when the vertical ruled line P2 is pressed and formed with the pressing blade 10, it is impossible to specify at which position of the peak portion or valley portion of the center core Q1 the pressing blade 10 hits. When the pressing blade 10 hits the center of the peak or valley of the center core Q1 and the center cores Q1 on both the left and right sides through the vertical ruled line P2 are in the same state, it can be folded along the vertical ruled line P2 to some extent accurately. . However, if the pressing blade 10 is displaced from the center position of the peak or valley of the center core Q1, the ease of crushing of the left and right center core Q1 via the vertical ruled line P2 becomes asymmetric, which is formed during folding. The crease line is displaced from the original ruled line position.
[0007]
That is, when the vertical ruled line P2 is folded, even if it can be folded along the vertical ruled line P2 up to about 90 ° as shown in FIG. 4 (a), it exceeds 90 ° as shown in FIG. 4 (b). When folded, the cores Q1 facing each other through the vertical ruled line P2 are crushed together, and these cores Q1 serve as resistance during bending. In this case, the folding direction tends to be biased in a direction with less resistance, and when the center core Q1 opposed through the vertical ruled line P2 is in an asymmetric state, it is difficult to accurately fold the crease from the vertical ruled line P2. become.
[0008]
As described above, the crease of the vertical ruled line P2 is shifted due to the resistance of the center core Q1, and the defective product as described above is generated. In particular, since the bending process is performed by a twist belt or the like, the bending process is gradually performed from the front during bending. For this reason, the crease is gradually shifted and inclined, and the fishtail phenomenon is likely to occur. Moreover, since it bends while pushing the flap from the outside, excessive folding easily occurs.
[0009]
As a countermeasure, the inventor proposed a bent ruled line in which a large number of short straight lines extending in a direction perpendicular to the main ruled line part are arranged adjacent to the main ruled line part, and an adjacent part is formed by crushing with the main ruled line part. (Patent Document 1). Further, a configuration in which the adjacent portion is formed asymmetrically in a part or the whole of the entire length of the ruled line portion, for example, a configuration in which the adjacent portion is provided only on the side opposite to the direction in which the folding line is easily displaced when folded is proposed ( Patent Document 2).
[0010]
According to these folding ruled lines, when the main ruled line part is folded as a crease and the opposing cores of the corrugated paper collide with each other and are crushed, the average strength of the core is reduced by the adjacent part, so it is easy Is crushed. Furthermore, if the adjacent portion is provided asymmetrically, it is possible to effectively prevent the displacement and bending of the folding line in a specific direction during folding.
[0011]
However, if the adjacent portion is excessively provided, the ruled line portion is naturally indistinct and the folding line is shifted. For this reason, the amount of the adjacent portion must be minimized. In addition, in order to provide the adjacent portion only on the side opposite to the direction in which the folding line is easily displaced during folding, it is necessary to consider the position of the adjacent portion. The optimum form of the adjacent portion is determined by the properties of the corrugated paper, the shape and dimensions of the box, the characteristics of the box making machine, etc., and it is difficult to know in advance.
[0012]
Thus, for the corrugated cardboard, this core has become a serious cause of hindering the folding accuracy of the ruled line. For this reason, the ruled line structure described in Patent Document 3 has also been proposed.
[0013]
The ruled line structure described in Patent Document 3 is a ruled line structure in which auxiliary ruled lines inclined with respect to a ruled line are pressed and formed symmetrically on both sides of a ruled line pressed and formed on a cardboard.
[0014]
[Patent Document 1]
JP-A-9-70905 [Patent Document 2]
Japanese Patent No. 28999797 [Patent Document 3]
Japanese Patent No. 3165659 [0015]
[Problems to be solved by the invention]
However, in Patent Document 3, since the center core that maintains the box strength is crushed by the auxiliary ruled line in a wide range, not only the strength around the vertical ruled line is remarkably lowered, but also the There is also a possibility that strength will fall.
[0016]
Further, as in Patent Document 3, even if the auxiliary ruled line is inclined with respect to the ruled line, if the auxiliary ruled line is provided in a symmetrical shape, the portion where the auxiliary ruled line is not provided is relatively centered via the vertical ruled line. It remains in the facing position and becomes a resistance when these cores are folded. In addition, if these cores are in an asymmetrical state via the vertical ruled lines, it becomes easy to incline toward the direction with less resistance, and the possibility that the folding position shifts as described above has not been completely eliminated.
[0017]
Furthermore, in order to reduce the resistance of the core when folding the vertical ruled line as much as possible, when both sides along the vertical ruled line are crushed widely, the vertical ruled line becomes unclear, and when folded along the vertical ruled line, There is a possibility that the stress of the folding line that becomes the folding base point is dispersed and the folding line is shifted other than the vertical ruled line. As a result, the crease line that is the base point from the beginning of folding is not determined, and the folding cannot be accurately performed along the vertical ruled line.
[0018]
Accordingly, the present invention has been created to solve the above-mentioned problems, and it is possible to fold a vertical ruled line along the center core step very accurately and to manufacture a highly accurate cardboard box. An object is to provide a structure, a ruled line forming apparatus, and a ruled line forming method.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, the first means of the present invention is a ruled line structure formed by pressing on a corrugated cardboard and provided along the step of the corrugated core Q1, and both left and right sides of the main ruled line 1 along the step. When the adjacent recesses 2 recessed in a substantially wave shape in cross section are alternately pressed and formed, and the fitting portions 3 are provided in the portions that remain adjacent to the adjacent recesses 2 and are not pressed, and are folded along the main ruled line 1 In addition, the fitting portion 3 is provided so as to be fitted into the adjacent concave portion 2 facing each other.
[0020]
The adjacent concave portion 2 of the second means extends in a direction perpendicular to the main ruled line 1 and is formed so as to gradually become shallower as it moves away from the position formed in contact with the main ruled line 1 and at substantially the same depth as the main ruled line 1. In addition, the width of the bottom portion of the adjacent recess 2 is formed to be wider than the width of the top portion of the fitting portion 3.
[0021]
The ruled line forming apparatus of the third means is a ruled line forming apparatus that presses the corrugated cardboard Q and provides ruled lines along the corrugated core Q1. In this apparatus, there are provided pressing blades 10 for pressing and forming the main ruled lines 1 along the steps, and on the left and right sides of the pressing blades 10 are alternately provided pressing dies 11 for forming adjacent recesses 2 that are recessed in a substantially wave shape in section, The pressing die 11 forms the adjacent concave portion 2 that gradually becomes shallower as it is away from the main ruled line 1, and the width of the bottom portion of the adjacent concave portion 2 is wider than the width of the top portion of the fitting portion 3 that faces the adjacent concave portion 2. Form.
[0022]
The ruled line forming method of the fourth means is a ruled line forming method in which the cardboard Q is pressed and a ruled line is provided along the step of the core Q1 of the cardboard Q. In this molding method, a part of the surface of the corrugated cardboard Q is humidified, and the humidified portion is alternately provided with the main ruled line 1 along the step and the left and right sides of the main ruled line 1 and adjacent to the corrugated cross section. It is to press-mold the concave portion 2 at the same time and to dry the humidified portion after molding so as to keep the shape of the main ruled line 1 and the adjacent concave portion 2.
[0023]
According to the present invention, when the main ruled line 1 is folded over 90 ° by alternately pressing the adjacent concave parts 2 having a substantially wave-shaped cross section on both the left and right sides of the main ruled line 1, the main ruled line 1 is adjacent to the main ruled line 1. The fitting portion 3 facing the recess 2 is fitted into the adjacent recess 2. Therefore, the main ruled line 1 can be accurately folded without receiving the resistance of the center core Q1, and the fitting portion 3 fitted in the adjacent recess 2 maintains the strength around the main ruled line 1. Further, since the fitting portions 3 are alternately arranged along the main ruled line 1, the bending stress is concentrated at the contact point between the main ruled line 1 and the fitting portion 3 at the beginning of the main ruled line 1 folding. Prevent misalignment.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIGS. 5 to 14 show an embodiment of the ruled line structure or ruled line forming apparatus of the present invention, and the cross section is substantially wave-shaped on both the left and right sides of the main ruled line 1 along the step of the center core Q1 of the cardboard Q. The recessed adjacent recesses 2 are formed alternately. A fitting portion 3 is provided at a portion remaining without being pressed in a portion adjacent to the adjacent recess 2. And when it folds along the main ruled line 1, it provides so that the fitting part 3 may fit in the adjacent recessed part 2 which opposes (refer FIG. 14). The main ruled line 1 and the adjacent recess 2 shown in the figure are formed by pressing at the same time as the blank P forming the cardboard box is punched. In particular, the main ruled line 1 is formed as a vertical ruled line P2 of the cardboard box as shown in FIG. .
[0025]
The adjacent recess 2 extends in a direction perpendicular to the main ruled line 1. Further, it is formed at a position substantially in contact with the main ruled line 1 at a position in contact with the main ruled line 1, and is formed so as to gradually become shallower as it is farther from this position (see FIGS. 7, 10, and 13). That is, since it is not crushed so that it leaves | separates from the main ruled line 1, the intensity | strength of the main ruled line 1 periphery is maintained, and the periphery of the main ruled line 1 is deeply pressed and is effectively weakened, so that it approaches the main ruled line 1. In addition, the inclination angle and length of the adjacent recessed part 2 are not limited to the example of illustration, A design change is arbitrary.
[0026]
It forms so that the width | variety of the bottom part of the adjacent recessed part 2 may become wider than the width | variety of the top part of the fitting part 3 (refer FIG.6, FIG.9, FIG.12). With this configuration, when folded along the main ruled line 1, it is possible to fold until the fitting portion 3 comes into contact with the back in the adjacent recess 2. Moreover, when the fitting part 3 fits in the adjacent recessed part 2, the periphery intensity | strength of the main ruled line 1 weakened by the adjacent recessed part 2 is reinforced. In the illustrated example, the width of the bottom portion of the adjacent concave portion 2 is clearly wider than the width of the top portion of the fitting portion 3, but these lengths can be arbitrarily changed. It is also possible to set the width of the top of the fitting part 3 to be slightly different.
[0027]
The ruled line forming apparatus of the present invention includes a pressing blade 10 that presses and forms a main ruled line 1 along a step, and a pressing die 11 that alternately forms adjacent concave portions 2 that are recessed in a substantially wave shape on both the left and right sides of the main ruled line 1. Are used (see FIGS. 5, 8, and 11). The pressing blade 10 is fixed to the support base 13, and the pressing dies 11 are alternately mounted on the left and right along the longitudinal direction of the pressing blade 10. The pressing die 11 is formed so as to form the adjacent concave portion 2 that gradually becomes shallower as it is away from the main ruled line 1 and the width of the bottom portion of the adjacent concave portion 2 is wider than the width of the top portion of the fitting portion 3.
[0028]
The pressing die 11 of the ruled line forming apparatus shown in FIG. 5 has a pressing surface 11A that extends obliquely upward from the tip of the pressing blade 10. When the corrugated cardboard Q is pressed by this device, the adjacent concave portion 2 is formed in a substantially wave-shaped cross section as shown in FIG. 6, and the adjacent concave portion 2 gradually becomes shallower as it moves away from the main ruled line 1 as shown in FIG. Formed.
[0029]
The stamping die 11 of the ruled line forming apparatus shown in FIG. 8 has a molding plate 12 bonded to the upper surface of the backing plate 14 and is disposed so as to face the pressing die 11. At this time, the tip of the pressing blade 10 is set to protrude downward from the pressing die 11. When the contact plate 14 is raised in this state, the main ruled line 1 is formed deeper than the adjacent recess 2 and protrudes downward (see FIG. 10). By forming such a main ruled line 1, it becomes possible to concentrate the stress at the time of folding along the main ruled line 1, so that the folding operation can be further facilitated. The material of the stamp 11 and the molding plate 12 is preferably plastic, but may be changed to a relatively hard elastic material such as cork. The illustrated contact plate 14 is a punched plate for punching the cardboard Q to form a blank P. When the blank P is formed, the main ruled line 1 and the adjacent recess 2 are formed simultaneously. When the corrugated cardboard Q is pressed by this apparatus, the adjacent concave portion 2 is formed to have a substantially wave-shaped cross section as shown in FIG. 9, and the adjacent concave portion 2 gradually becomes shallower as it moves away from the main ruled line 1 as shown in FIG. Formed.
[0030]
A pressing die 11 of the ruled line forming apparatus shown in FIG. 11 has a pressing surface 11B that presses the bottom of the adjacent recess 2 substantially horizontally and a pressing surface 11A that extends obliquely upward from the pressing surface 11B. The tip of the pressing blade 10 is set so as to protrude downward from the pressing die 11. As shown in FIG. 12, the pressing die 11 is set so as to be recessed in a substantially wave shape in which the cross section of the adjacent concave portion 2 is square. Therefore, a schematic plan view of the adjacent concave portion 2 pressed by the pressing die 11 and the fitting portion 3 not pressed by the pressing die 11 is as shown in FIG. Further, as shown in FIG. 13, the bottom of the adjacent recess 2 is formed substantially horizontally, and is formed so as to gradually become shallower as the distance from the bottom decreases. Further, the main ruled line 1 is formed deeper than the adjacent concave part 2, and the folding operation of the main ruled line 1 can be facilitated without using the molding plate 12 used in FIG.
[0031]
As a method of forming the main ruled line 1 and the adjacent concave portion 2, there is a method of humidifying the cardboard Q in advance. That is, a part of the surface of the corrugated cardboard Q is humidified, and in the humidified portion, a main ruled line 1 along the step and an adjacent concave part 2 provided alternately on the left and right sides of the main ruled line 1 and recessed in a substantially wave shape in cross section Is pressed. It is preferable that the humidified portion is limited to a portion where the main ruled line 1 and the adjacent concave portion 2 are press-molded as much as possible. Further, the humidification method can be arbitrarily selected, such as a means for spraying hot water or water in the form of a mist, or a means for applying with a brush.
[0032]
Further, when a cardboard box is formed, a part of the cardboard Q is humidified before the blank P is formed, and the blank P is punched out from the cardboard Q. At the same time, the main ruled line 1 and the adjacent recess 2 Are formed at the same time.
[0033]
After forming the main ruled line 1 and the adjacent recess 2, the humidified portion is dried to preserve the shapes of the main ruled line 1 and the adjacent recess 2. Thus, by humidifying the cardboard Q, the main ruled line 1 and the adjacent recess 2 can be clearly pressed and formed. Moreover, these shapes can be maintained for a long time after drying.
[0034]
【The invention's effect】
The above object of the present invention achieves the original object. That is, the adjacent recesses 2 that are recessed in a substantially wave shape in cross section are alternately pressed on the left and right sides of the main ruled line 1 along the step of the center core Q1 of the cardboard Q, and the adjacent recesses 2 are not pressed adjacently. The fitting portion 3 is provided at the remaining portion, and when it is folded along the main ruled line 1, the fitting portion 3 is provided so as to be fitted into the adjacent adjacent concave portion 2, thereby reducing the resistance of the core Q1. Without being received, the main ruled line 1 can be accurately folded up to the position where it folds.
[0035]
Therefore, according to the present invention, as shown in FIG. 2, when the vertical ruled line P1a of the blank P is folded and the glue piece P3 is bonded, the illustrated symbols a and b are always kept at an accurate interval, The problem of the error between the symbols a and b has been solved. As a result, a highly accurate cardboard box can be provided.
[0036]
Further, the adjacent concave portion 2 extends in a direction perpendicular to the main ruled line 1 and is formed so as to gradually become shallower as it moves away from a position formed in contact with the main ruled line 1 and at substantially the same depth as the main ruled line 1. Therefore, the strength around the main ruled line 1 in which the adjacent concave portion 2 is provided is effectively weakened as the distance from the main ruled line 1 is approached, and the original strength is maintained as the distance from the main ruled line 1 is increased. As a result, the conventional inconvenience of remarkably weakening the strength around the main ruled line 1 while increasing the folding accuracy of the main ruled line 1 has been solved.
[0037]
Furthermore, since the width of the bottom part of the adjacent recessed part 2 is formed so as to be wider than the width of the top part of the fitting part 3, the fitting part 3 is fitted to the back of the adjacent recessed part 2. This state has the effect of increasing the strength of the fitting portion near the main ruled line 1 and increasing the strength of the corrugated cardboard box after assembly.
[0038]
On the other hand, according to the ruled line forming apparatus of the present invention, the pressing blade 10 for pressing and forming the main ruled line 1 along the step is provided, and the pressing mold for forming the adjacent concave portions 2 recessed in a substantially wave shape in cross section on the left and right sides of the pressing blade 10. 11 are alternately formed, and the pressing die 11 forms the adjacent concave portion 2 that gradually becomes shallower as it is separated from the main ruled line 1, and the width of the top portion of the fitting portion 3 where the width of the bottom portion of the adjacent concave portion 2 faces the adjacent concave portion 2 Therefore, the main ruled line 1 and the adjacent recess 2 can be easily formed.
[0039]
Further, in the ruled line forming method of the present invention, a part of the surface of the corrugated cardboard is humidified, the main ruled line 1 and the adjacent concave part 2 are press-formed to the humidified part, and the humidified part is dried after forming and adjacent to the main ruled line 1. Since the shape with the concave portion 2 is preserved, the main ruled line 1 and the adjacent concave portion 2 can be clearly pressed and formed, and after the humidified portion is dried, these shapes are stable and have an effect of being maintained for a long time. is there.
[0040]
As described above, according to the present invention, it is possible to fold a cardboard ruled line very accurately and to provide various beneficial effects such as providing a highly accurate cardboard box.
[Brief description of the drawings]
FIG. 1 is a plan view showing a blank forming a cardboard box.
FIG. 2 is a plan view showing a state in which a blank is folded and a paste margin is bonded.
FIG. 3 is a conceptual diagram showing the positional relationship between the corrugated core and the pressing blade.
FIGS. 4A and 4B are diagrams illustrating a state in which a cardboard is folded from a main ruled line, FIG. 4A is a conceptual diagram illustrating a state in which the cardboard is folded up to 90 °, and FIG.
FIGS. 5A and 5B show an embodiment of the ruled line forming apparatus of the present invention, in which FIG. 5A is a cross-sectional view of the main part before pressing and FIG.
6 is a cross-sectional view taken along line AA shown in FIG.
7 is an end view showing main ruled lines and adjacent recesses formed by the ruled line forming apparatus shown in FIG. 5. FIG.
FIGS. 8A and 8B show another embodiment of the ruled line forming apparatus of the present invention, in which FIG. 8A is a cross-sectional view of the main part before pressing and FIG.
FIG. 9 is a cross-sectional view taken along line AA shown in FIG.
10 is an end view showing main ruled lines and adjacent recesses formed by the ruled line forming apparatus shown in FIG. 8. FIG.
11A and 11B show another embodiment of the ruled line forming apparatus of the present invention, where FIG. 11A is a cross-sectional view of the main part before pressing and FIG.
12 is a cross-sectional view taken along line AA shown in FIG.
13 is an end view showing main ruled lines and adjacent recesses formed by the ruled line forming apparatus shown in FIG. 11. FIG.
14 is a schematic plan view of a main part showing adjacent concave portions and fitting portions formed by the ruled line forming apparatus shown in FIG. 11. FIG.
[Explanation of symbols]
P Blank P1 Horizontal ruled line P2 Vertical ruled line P3 Paste piece Q Corrugated cardboard Q1 Core 1 Main ruled line 2 Adjacent recess 3 Fitting part 10 Pressing blade 11 Stamping die 11A Pressing surface 11B Pressing surface 12 Molding plate 13 Supporting base 14 Base plate
