JP3554541B2

JP3554541B2 - Coreless winding shaft for continuous sheet

Info

Publication number: JP3554541B2
Application number: JP2001027929A
Authority: JP
Inventors: 大三杉山; 建三杉山
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-08-23
Filing date: 2001-02-05
Publication date: 2004-08-18
Anticipated expiration: 2021-02-05
Also published as: JP2002137856A

Description

【０００１】
【発明の属する技術分野】
本発明は紙管等のコアを用いずにコアレス状に食品包装フィルム（ラップシート）等の連続シートを均等な真円形状の円筒形状に巻取るための連続シート用コアレス巻取軸に関する。
【０００２】
【従来の技術】
食品包装フィルムとして用いられる塩化ビニリデン系フィルムやポリエチレンフィルムなどの樹脂フィルムシートを円筒形状に巻取る従来の手段としては、紙管などのコアをコアの内側から巻取軸の出没自在なラグで支持され、進出されたラグでコアを内側から支持した状態でコアを回転させ、この回転されるコアに巻き取り素材の延伸性を利用して強い張力を掛けながら樹脂フィルムシートを巻きつけ、コアに円筒形状に巻きつけられた樹脂フィルムシートはラグを後退させて、支持状態を解除して、コアごと巻取軸から抜き取るようにしている。このように巻き取られた樹脂フィルムシートはコアに円筒形状に巻きつけられた状態で需要者に提供される。
【０００３】
一方、シートをコアレス状に巻取る技術としては実開平４−３１７５３号の「トイレットペーパ巻取用のエアーシャフト」が開示されている。このエアーシャフトは芯（紙管）なし連続シートとしてのトイレットペーパを巻取るために提案されたものであり、その構造においてはエアーシャフトの筒体に半径方向に出没する整列ラグが設けられており、断面形状が円弧状で軸方向に延びる複数のリーフが円周方向に分割して前記各列のラグに個別に固定された構造となっている。ラグが半径外方に突出したとき、リーフもそれに順じて半径外方に拡開され、この状態においてリーフの外周に紙管を用いることなくシートが直接巻き取られる。隣接したリーフ間には軸線方向の全長に延びる隙間が形成されるが、この隙間は狭いためリーフは全体としては一つの円筒面を形成し、この回りにシートをロール状に巻取ることができる。そして、巻き取り完了時にはラグを半径内方に収縮させると、リーフもそれに順じて半径内方に変位し、エアーシャフトは縮径するため巻き取られたシートロールを引き抜くことができ、無心ロールが完成する。
【０００４】
【発明が解決しようとする課題】
実開平４−３１７５３号に開示の従来技術では巻き取り時において隣接リーフ間においてシャフト全長に渡ってシャフト軸線と平行に延びる隙間が円周方向に等間隔に複数（リーフの数分）形成される。即ち、隙間の部分ではシートは支持されておらず、換言すれば、シートを支持しない隙間の部分がシャフトの全長に亘ってシャフト軸線と平行に延びている。トイレットペーパのように巻き取り張力が低い場合は内周での面圧も高くはならなためリーフ間の隙間はロール内周面での型崩れの原因には実質的にならない。ところが、実開平４−３１７５３号に開示のエアーシャフトにより樹脂シートを巻き取ろうとすると、樹脂シートの場合は巻き取り張力が高いため、シートの巻き取り面が前記隙間部分において円弧状にならず、直線状態になっていまい、真円形状の巻き取り円筒面を形成できない。また、巻き取り中のシートペーパの張力が内周側のシートペーパを半径方向に押すように作用されるので、前記隙間に位置する部分ではロールの内周面に全長に亘って延びる数条の突起ができてしまう。このような全長に亘る突起部はたとえ内周面にあったとしても目立つため製品の見栄えは悪くなるため、商品としての価値が損なわれる。そのため、実開平４−３１７５３号に開示の技術は樹脂シートの無心ロールの形成のために適しているとはいえなかった。
【０００５】
従来の技術の問題点としてリーフ間の隙間はシャフト軸線に沿って全長に渡って延びている。そのため、シャフトを巻取りローラに押付けて巻回する場合に、隙間の部分においてはシャフトは巻取りローラと接触する円周面が全く欠如するため、巻き始めにおいては回転中にシャフトが隙間の部位に来るたびにシャフトは上下動し円滑な回転がなしえず、高速回転で運転することができず、また大きな騒音を発生していた。
【０００６】
本発明の第１の目的はこのような実情に鑑み、食品包装フィルム（ラップシート）などの連続シートを紙管などのコアを用いることなくしかも真円形状の内周面の形状を実質的に維持しつつ巻取りうるようにすることにある。
【０００７】
また、本発明の第２の目的は、巻取軸を駆動ローラの外周面に押付けることにより巻取軸にシートを巻き取る場合において、シャフトを伸縮可能とするためのリーフ間における隙間の存在にかかわらず、シャフトをいつも円周面において駆動ローラに当接せしめるようにし、これによりシャフトの回転を円滑とし、連続シートの巻き取り巻き始めから高速で行いうるようにするもものである。
【０００８】
また、本発明の第３の目的は、食品包装フィルムなどの樹脂フィルムシートを紙管などのコアを用いずにコアレス状に巻取る巻取軸において、前記巻取軸に巻き取られた密着性を有する樹脂フィルムシートのロールを巻き取り完了後に前記巻取軸から容易に抜き取りうるようにすることである。
【０００９】
【課題を解決するための手段】
請求項１に記載の発明によれば、食品包装用フィルムとしての連続シート用であって、筒状軸体と筒状軸体内の膨張体と筒状軸体の外側における複数のリーフとを具備し、前記複数のリーフの各々は軸線方向に延びると共に、複数のリーフは円周方向におけるそれぞれの角度範囲を占めるように分割して配置され、前記膨張体の膨張時に前記リーフを半径外方に拡開させるように膨張体とリーフとを協働させる協働手段を備え、このリーフ拡開状態においてその外周に連続シートをロール状に巻回し、膨張体の収縮により連続シートのロールを抜去しうるシート用巻取軸において、連続シートのロール状の巻回のため巻取軸は連続シートを介しての駆動ローラとの接触により回転されるようにされ、各リーフの回転方向の両側縁部は軸線方向に延びた突辺もしくは底辺と円周方向に延びる側辺とを軸線に沿って交互に形成すると共に、円周方向に隣接した一対のリーフの対向側縁部は相補的に対向し、かつ各リーフの各側縁部における前記側辺は円周方向において隣接するリーフの対向した側辺と当接していることを特徴とする連続シート用コアレス巻取軸が提供される。
【００１０】
請求項１の発明の作用効果を説明すると、リーフの軸線方向縁部はシャフト軸線に沿って円周方向にシフトしており、かつ円周方向に隣接したリーフの対向縁部は相補的に対向している。そのため、膨張体の膨張時の半径外方へのリーフの拡開の際にリーフ間の対抗縁部間に隙間が形成されるも、この隙間はシャフトと軸線に沿って円周方向にシフトしている。即ち、拡径時のリーフ間の隙間の存在により隙間の部位においてシートが面圧を受けないため、樹脂シート（ラップフィルム）のように巻取り張力が相対的に高い場合は特に、この部位が真円形状から外れうる（完成したロール内周におけるすじとなりうる）が、従来のようにリーフ間の隙間がシャフト全長に亘ってシャフト軸線に沿って真直ぐではないため、シートの無支持部分（隙間の部分）において、シートが間隙に向けて押し込まれようとする力に対して間隙の部位に対して軸線方向において隣接するリーフの部分（シート支持部分）がシートを引張り上げるような作用を達成し、シートが溝に押し込まれるような力は全体として減少される。そのため、巻取り時におけるリーフ間の隙間部分における食い込みとしてのロールの内周における突起状のすじが目立たなくなり、相対的な美麗な内周面形状を提供することができ、ロール製品としての外観が損なわれる度合いが少なくなる効果がある。
【００１１】
また、リーフ拡径時の隙間がシャフト軸線に沿って円周方向にシフト（シフト形状としては凹凸、鋸刃、山形など各種の形態をとりうる）配置しているため、このシャフトを駆動ローラの外周に圧接させて、連続シートをロール状に巻き取る場合に、シャフトは駆動ローラに接触する円周面をシャフトの軸線方向における或る位置において必ず有している。そのため、隙間の存在にかかわらずシャフトは全体としてはどの角度位置においても駆動ローラと実質的に円周面で接触するため、円滑な回転が得られ、巻取り時の振動が少なくなり、巻き始めからの高速回転が可能となり、効率を高めることができ、かつ作動騒音が少ない利点がある。
【００１２】
更に、ロールへの巻取り完了に際しては膨張体、即ち、リーフへの半径外方への加圧を解消させることによりロールをシャフトより容易に引き抜くことができる。
また、リーフの縁部における側辺は円周方向において隣接するリーフの対向した側辺と当接しているため、巻取軸の拡縮に関わらず隣接するリーフ間は軸線方向対抗面がいつも当接した関係にあり、この部分では巻取軸の拡径状態においても隙間が残らない効果がある。
【００１３】
請求項２に記載の発明によれば、請求項１に記載の発明において、円周方向に分割された各リーフは軸線方向の全長に亘って一体であることを特徴とする連続シート用コアレス巻取軸が提供される。
【００１４】
請求項２の発明の作用・効果を説明すると、リーフは円周方向には分割されているが、各リーフは長手方向においてはその全長に亘って１枚ものである。そのため、構造的には単純となり、部品点数も少ないことからコスト的には有利となる。
【００１５】
請求項３に記載の発明によれば、請求項１に記載の発明において、各リーフは軸線方向においても多数に分割されていることを特徴とする連続シート用コアレス巻取軸が提供される。
【００１６】
請求項３の発明の作用効果を説明すると、リーフを円周方向に分割すると共に軸線方向にも分割構造となっている。軸線方向への分割構造としたため、各リーフ毎に取り付けが行われ、１個当たりの嵌合部（芯合の必要な部分）は少なくなるため、一体とした場合と比較して部品精度の管理が楽となり、かつ取付作業も容易となる利点がある。
【００１７】
請求項４に記載の発明によれば、請求項１に記載の発明において、前記各リーフの外表面に、樹脂フィルムに対し低接着性の材料層を形成されたことを特徴とする連続シート用コアレス巻取軸が提供される。樹脂フィルムの接触面においてシャフトに低接着性の材料層を有していることを特徴とする連続シート用コアレス巻取軸が提供される。
【００１８】
請求項４の発明の作用効果を説明すると、リーフ表面の低接着性の材料層によりポリエチレンのように密着性の高いフィルムを巻取軸により巻回した場合にあってもフィルムとの接触面においてシャフト表面は低接着材料より構成されているため、シャフトからのロールの離脱を容易に行うことができる。
【００２１】
【発明の実施の形態】
以下、本発明の巻取軸について図面を参照しながら説明する。本発明の巻取軸はリーフタイプの空気圧拡縮型巻取軸をベースとしたものであり、その基本構造を図１及び図２を参照して説明する。図１はリーフを拡張した巻き取り時の巻取軸を示す断面図であり、図２はリーフを縮小した抜き取り時の巻取軸を示す断面図である。同図において符合１は巻取軸を示し、この巻取軸１は円筒状の軸体２内に空気の注入によって膨張され空気の抜き取りによって収縮されるゴム製の弾性チューブからなる膨張体３を配設し、軸体２に形成されたラグ孔４に遊嵌され、膨張体３の膨張又は収縮作用によってラグ板５を介して軸体２の半径方向に向けて進退移動される数列のラグ６を設け、ラグ６に断面形状が円弧状で軸方向に延びる複数（４個）のリーフ７を前記各列のラグ６に個別に固定して構成されている。空気の注入によって膨張体３が膨張され、この膨張によって半径外方向に向けてラグ６が進出移動され、その結果リーフ７は半径外方に拡径される。この拡径状態を図１で示し、このとき各リーフ７は完全円の円周上に位置しており、この状態においてラップフィルムなどのシートのロール状巻取りが実施される。拡径状態ではリーフ７は円周上に位置しているが、円周方向に隣接したリーフ７間の縁部は隙間Ｌを持って対向している。円周方向には隙間Ｌは等間隔（９０度毎）に配置される。
【００２２】
膨張体３からの空気の排出によってラグ６を介して複数の膨張体３が収縮され、この収縮によって進出位置から後退移動されたラグ６を介してリーフ７が実線位置まで縮小され、この状態を図２で示す。図１の拡径状態（図２では拡径状態の巻取軸１の外周を一点鎖線Ｃにて表す）と図２の縮径状態との径差を利用してロールを抜き取ることができる。膨張体３への空気の注入及び排出は巻取軸１の一端側に設けられた図示しない吸排口を介して行なわれる。このようにリーフタイプの巻取軸は、リーフ７が拡張される巻き取り時には、隣接される各リーフ７の側縁部の間隙溝（Ｌ）が拡大されるように構成されている。巻取軸１の軸体２、ラグ板５を含むラグ６、及びリーフ７は金属製である。ラグ６に固定されるリーフ７は、ラグ６と別体のものをビス止めなどの固着手段で固定下ものでよく、ラグ６と一体に形成したものでもよい。
【００２３】
次ぎに、本発明の特徴であるリーフ７の構造について図３を加えて説明する。図３は巻取軸１の全体斜視図を下側に示し、その上側にそのうちの１枚のリーフ７を斜視図にて示している。各リーフ７の軸方向に沿う両側縁部を軸方向に均等に区分けされた複数の突出縁部８と後退縁部９とに交互に形成し、突出縁部８には軸方向に延びる突辺８Ａと該突辺８Ａに交わる両突出側辺８Ｂを有し、後退縁部８には軸方向に延びる底辺９Ａと該底辺９Ａと交わる両後退側辺９Ｂを有する。即ち、各リーフ７の軸線方向の縁部は巻取軸１の長手方向軸線に沿って円周方向に交互にシフトしており、図５に示すようにコの字状の凹凸形状を呈している。そして、円周方向に隣接するリーフ７間の対向縁部は相補的な関係にあり、図１〜図３に示す第１の実施形態においては隣接される前記両側各リーフ７の突出縁部８と後退縁部９とは互いに差込まれる関係にある。従って、巻取軸１の拡径時に隣接するリーフ７間に形成される隙間Ｌは図３及び図５に示すように巻取軸１の軸線方向に沿って交互に反対方向にシフトしている。
【００２４】
また、図３に示したリーフの実施形態においては、突出縁部８の両側突出側辺８Ｂと後退縁部９の両後退側辺９Ｂはリーフ７の円周方向に沿って延設している。すなわち、突出縁部８の両側突出側辺８Ｂを軸方向に延ばされた軸方向に延ばされた前記突辺８Ａと直交させ、後退縁部９の両後退側辺９Ｂを軸方向に延ばされた前記底辺９Ａと直交させ形成してある。突出縁部８と後退縁部９の各側辺８Ｂ、９Ｂをこのように形成したことにより、リーフ７の拡張時であっても前記各側辺８Ｂ、９Ｂの間に間隙溝が拡大形成されないように構成している。即ち、円周方向に隣接したリーフ間において側辺８Ｂと９Ｂとは巻取軸の拡縮に関わらずいつも近接（又は接触）した関係を維持するためこの部分において実質的に隙間が形成されることがない。
【００２５】
巻取り時に回転駆動される巻取軸１の回転駆動は適宜手段により行われるが、図４に示すように、巻取軸１の回転駆動を巻取軸の軸端（図示しない）を回転自在に軸支し、巻取軸１の外周面をローラ10, 10'（その一方（例えばローラ１０）は駆動ローラ）の外周面に圧接的に外接せしめ、その上を押えローラ１１にて押付け、この駆動ローラ１０の回転駆動力を介して巻取軸１を回転駆動させ、巻取軸１の回りに矢印のように送られてくるラップフィルム１２などのシートを巻回する。１４はシートが所定外径のロールに巻き取られた状態を示し、１´はそのときの巻取軸の位置、１１´はロール完成時における押えローラの位置を示す。巻取りローラ10, 10'に圧接させてシートの巻取りを行う際に、一つの横断面においては図１に示すように円周方向に沿ってリーフ間に４個の隙間Ｌが存在する。しかしながら、隙間Ｌの存在はシートをロール状に巻取るに際し型崩れの原因とならない。即ち、図５は図１〜図３の第１実施形態における巻取軸１の拡開時における軸線方向におけるリーフ間の隙間Ｌの分布を模式的に示す。この実施形態においては、隙間Ｌは巻取軸１の軸線１´に沿って円周方向に交互に反対方向にシフトしている。換言すれば、リーフ間の隙間Ｌは巻取軸１の軸線の全長には延びていない。そのため、図４のように巻取軸１をローラ10, 10'に周面接触させてシート１２を巻き取る際に、巻取軸１は横断面では必ずリーフ間に隙間Ｌを有しているがこの隙間Ｌは巻取軸１の全長に亘って軸線に平行ではないため、巻取軸１の軸線方向でみれば巻取軸１は巻取りローラ10, 10'に円周面で接触する部位を必ず有している。そのため、リーフ７のこの部位において巻取軸１は駆動ロール10, 10'のロール面と実質的に円と円とで圧接する状態となり、リーフ間に軸方向の全長に延びる隙間を形成された従来のリーフタイプの巻き取りシフトと異なり、間隙溝Ｌに起因した振動が実質的になく、スムースな回転が得られるため巻取り当初からの高速巻取りが可能であり、かつ騒音の問題もない。
【００２６】
各リーフ７の巻きつけ表面には、ガラス繊維布などのメッシュ状の布にポリ（４）ふっ化エチレンなどの摩擦係数が小さく接着性に乏しい樹脂を含浸させた積層テープを張りつけて積層形成しておくのが好ましい。これにより、密着性を有する樹脂フィルムシートと接着され易い金属性のリーフ７の巻きつけ表面を前記樹脂フィルムシートが軽く接着され、離脱させる力が働いた際には容易に離脱されるように構成し、前記リーフの巻きつけ表面に巻き取られた密着性を有する樹脂フィルムシートのロールをリーフ７の縮小時に巻取軸から容易に抜き取りうるようにしている。
【００２７】
また、各リーフ７の外周に前記積層テープと同様な材質からなる外層チューブを被せて、前記積層テープの場合と同様に、密着性を有する樹脂フィルタと接着され易い金属性リーフ７の巻きつけ表面を前記樹脂シートが軽く接着され、離脱させる力が働いた際には容易に離脱されるように構成し、リーフ７の巻きつけ表面に巻き取られた密着性を有する樹脂フィルムシートのロールをリーフ７の縮小時に巻取軸から容易に抜き取りうるように構成しても良い。このように、前記積層テープと同様な材質からなる外層チューブをリーフ７の巻取り表面に被せた構造であっても、前記外層チューブが前記間隙溝Ｌの位置において直線状になりにくく、またこの外装チューブが前記間隙溝Ｌに食い込まれ難いことは、樹脂フィルムシートの巻きつけで説明したのと同様である。
【００２９】
図６〜図８は別実施形態を示す。第１の実施形態では図３に示すようにリーフの分割を円周方向のみで、巻取軸１の軸線方向においてはその全長に渡ってリーフは一体形成として形成される。これに対して、図６〜図８の実施形態ではリーフ７０は円周方向のみならず、巻取軸１の軸線方向においても分割されている。図８はリーフ７０の円周方向及び軸線方向の分割構造を斜視図によって表している。図７において、板５０は軸体２０の内周において円周方向に等間隔に離間して配置され、図６に示すように当板５０には案内部５２がビス５３により固定される。軸体２０はスロット２０−１を有し、このスロット２０−１に案内部５２は半径方向には摺動自在にかつ軸線方向にはガタを実質的に生ずることなく嵌合されている。リーフ７０は案内部５２にビス７１により固定されている。図７において３０はゴムチューブなどの膨張体であり、その外周が当板５０と当接している。
【００３０】
この実施形態において、膨張体３０の膨張は当板５０及び案内部５２を介し対応のリーフ７０に伝達され、リーフ７０は半径外方に拡開した位置をとる。図７は巻取軸１の拡径状態を示す。拡径状態においては、円周方向に隣接したリーフ７０間に隙間Ｌが形成されるが、隙間Ｌは第１の実施形態と同様に巻取軸の軸線方向に沿っては交互に反対方向にシフトし、隙間Ｌは巻取軸の軸線全長には延びないため、巻取軸１はその軸線方向に沿って必ず円周面が駆動ローラと面接触しているため、第１の実施形態と同様にラップフィルムをロールに巻き取ったときのロール内周のすじ状の突起の発生を軽減することができるし、巻き始めからの円滑な回転が保障され、これらの作用・効果も他の実施形態のそれと同様である。
【００３１】
そして図６から図８の第２の実施形態ではリーフ７０は円周方向だけでなく軸線方向にも分割されており、一個一個軸体２０に装着してゆく構成であるため、製作時のビス５３，７１の軸孔などの精度管理が楽であるため、製造及び組立が容易となる作用・効果がある。
【図面の簡単な説明】
【図１】図１はこの発明の第１の実施形態における巻取軸の拡径状態の断面図である。
【図２】図２は図１の巻取軸の縮径状態の断面図である。
【図３】図３は図１の巻取軸を一つのリーフと共に示す概略的斜視図である。
【図４】図４のはこの発明の巻取軸によるラップフィルムなどのシートのロール巻取方式を概略的に示す図である。
【図５】図５はこの発明の巻取軸におけるリーフの縁部の形状を模式的に示す図である。
【図６】図６はこの発明の第２の実施形態の巻取軸の部分的軸方向断面図である。
【図７】図７は図６のＶＩＩ−ＶＩＩ線に沿って表されるこの発明の巻取軸の横断面図である。
【図８】図８は第２の実施形態の巻取軸をリーフを部分的に取外した状態で示す概略的斜視図である。
【符号の説明】
１…巻取軸
２…軸体
３…膨張体
５…ラグ板
６…ラグ
７…リーフ
８…突出縁部
９…後退縁部
１０，１０’…巻取りローラ
１２…ラップフィルム
２０…軸体
２０−１…スロット
３０…膨張体
５０…当板
５２…案内部
７０…リーフ
７１…ビス
Ｌ…間隙溝[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a coreless winding shaft for a continuous sheet for winding a continuous sheet such as a food packaging film (wrap sheet) into a uniform circular cylinder without using a core such as a paper tube.
[0002]
[Prior art]
Conventional means for winding a resin film sheet such as a vinylidene chloride film or polyethylene film used as a food packaging film into a cylindrical shape supports a core such as a paper tube from the inside of the core with a retractable lug on the winding shaft. Then, rotate the core while supporting the core from the inside with the extended lug, wind the resin film sheet around the rotated core while applying strong tension using the stretchability of the winding material, and wrap the resin film sheet around the core. The resin film sheet wound in a cylindrical shape retracts the lug, releases the support state, and removes the core together with the core from the winding shaft. The resin film sheet thus wound is provided to the consumer in a state of being wound around the core in a cylindrical shape.
[0003]
On the other hand, as a technique for winding a sheet in a coreless manner, Japanese Unexamined Utility Model Publication No. 4-31753 discloses an "air shaft for winding toilet paper". This air shaft has been proposed for winding toilet paper as a continuous sheet without a core (paper tube). In the structure, an alignment lug is provided on a cylinder of the air shaft so as to protrude and disappear in a radial direction. A plurality of leaves having an arc-shaped cross-section and extending in the axial direction are divided in the circumferential direction and individually fixed to the respective rows of lugs. When the lugs protrude radially outward, the leaves are also radially expanded accordingly, and in this state, the sheet is directly wound up without using a paper tube around the leaves. A gap is formed between adjacent leaves that extends the entire length in the axial direction. However, since this gap is narrow, the leaves form a single cylindrical surface as a whole, and the sheet can be wound around this in a roll shape. . When the lug is contracted inward when the winding is completed, the leaf is also displaced radially inward accordingly, and the air shaft is reduced in diameter so that the wound sheet roll can be pulled out, and the centerless roll Is completed.
[0004]
[Problems to be solved by the invention]
In the prior art disclosed in Japanese Utility Model Application Laid-Open No. 4-31753, a plurality of gaps (equivalent to the number of leaves) are formed at equal intervals in the circumferential direction between adjacent leaves at the time of winding, extending in parallel with the shaft axis over the entire length of the shaft. . That is, the sheet is not supported in the gap portion, in other words, the gap portion that does not support the sheet extends parallel to the shaft axis over the entire length of the shaft. When the winding tension is low as in the case of toilet paper, the surface pressure on the inner periphery cannot be increased, so that the gap between the leaves does not substantially cause the shape collapse on the inner peripheral surface of the roll. However, when the resin sheet is wound by the air shaft disclosed in Japanese Utility Model Laid-Open No. 4-31753, the winding tension of the resin sheet is high, so that the winding surface of the sheet does not have an arc shape in the gap portion. It is not possible to form a perfect circular winding cylindrical surface even if it is linear. In addition, since the tension of the sheet paper during winding is applied so as to press the sheet paper on the inner peripheral side in the radial direction, in the portion located in the gap, several lines extending over the entire length on the inner peripheral surface of the roll are provided. Protrusions will be formed. Such a protruding portion extending over the entire length is conspicuous even if it is on the inner peripheral surface, so that the appearance of the product deteriorates, and the value as a product is impaired. Therefore, the technique disclosed in Japanese Utility Model Application Laid-Open No. 4-31753 cannot be said to be suitable for forming an uncentered roll of a resin sheet.
[0005]
A problem with the prior art is that the gap between the leaves extends the full length along the shaft axis. Therefore, when the shaft is pressed against the winding roller and wound, the shaft has no circumferential surface in contact with the winding roller at the gap portion. Each time the shaft came up and down, it could not rotate smoothly, could not operate at high speed, and generated loud noise.
[0006]
In view of such circumstances, a first object of the present invention is to form a continuous sheet such as a food wrapping film (wrap sheet) without using a core such as a paper tube and to form a substantially circular inner peripheral surface substantially. It is to be able to take up while maintaining.
[0007]
A second object of the present invention is to provide a gap between leaves for allowing the shaft to expand and contract when the sheet is wound around the winding shaft by pressing the winding shaft against the outer peripheral surface of the drive roller. Irrespective of this, the shaft is always brought into contact with the driving roller on the circumferential surface, whereby the rotation of the shaft is smooth and the continuous sheet can be rotated at a high speed from the beginning.
[0008]
Further, a third object of the present invention is to provide a winding shaft for winding a resin film sheet such as a food packaging film in a coreless manner without using a core such as a paper tube. Is to be able to be easily removed from the winding shaft after the winding of the roll of the resin film sheet having the above.
[0009]
[Means for Solving the Problems]
According to the invention as set forth in claim 1, for a continuous sheet as a food packaging film , it is provided with a cylindrical shaft, an expanded body in the cylindrical shaft, and a plurality of leaves outside the cylindrical shaft. Each of the plurality of leaves extends in the axial direction, and the plurality of leaves are divided and arranged so as to occupy respective angular ranges in the circumferential direction. A cooperating means for cooperating the inflatable body and the leaf so as to expand is provided.In this leaf expanded state, a continuous sheet is wound around the outer periphery thereof in a roll shape, and the roll of the continuous sheet is removed by contraction of the inflatable body. In the sheet take-up shaft, the take-up shaft is rotated by contact with a driving roller through the continuous sheet for the roll-like winding of the continuous sheet, and both side edges in the rotational direction of each leaf. Is the axial direction Thereby forming a projecting side or base and circumferentially extending side edges extending alternately along the axis, a pair of leaf of opposed side edges adjacent to the circumferentially opposed complementary, and each leaf A coreless take-up shaft for a continuous sheet, characterized in that the side edges of each side edge portion of the sheet abut on opposite sides of an adjacent leaf in the circumferential direction .
[0010]
To explain the operation and effect of the first aspect of the invention, the axial edge of the leaf is shifted in the circumferential direction along the shaft axis, and the opposing edge of the leaf adjacent in the circumferential direction is complementarily opposed. are doing. Therefore, a gap is formed between the opposing edges between the leaves at the time of expansion of the leaves to the outside of the radius at the time of expansion of the expansion body, but this gap shifts in the circumferential direction along the shaft and the axis. ing. That is, since the sheet is not subjected to surface pressure at the site of the gap due to the existence of the gap between the leaves at the time of diameter expansion, especially when the winding tension is relatively high such as a resin sheet (wrap film), Although it may deviate from a perfect circular shape (it may be a streak on the inner circumference of the completed roll), since the gap between the leaves is not straight along the shaft axis over the entire length of the shaft as in the related art, the unsupported portion of the sheet (gap Portion), the leaf portion (sheet supporting portion) adjacent in the axial direction to the gap portion achieves the action of pulling up the sheet against the force of the sheet being pushed into the gap. The force which forces the sheet into the groove is reduced as a whole. Therefore, protruding streaks on the inner periphery of the roll as bites in the gaps between the leaves during winding are less noticeable, and a relatively beautiful inner peripheral surface shape can be provided, and the appearance as a roll product is improved. There is an effect that the degree of damage is reduced.
[0011]
In addition, since the gap at the time of leaf expansion is shifted in the circumferential direction along the shaft axis (the shift shape can take various forms such as irregularities, saw blades, and mountain shapes), this shaft is used as a drive roller. When the continuous sheet is wound into a roll by being pressed against the outer periphery, the shaft always has a circumferential surface in contact with the drive roller at a certain position in the axial direction of the shaft. Therefore, regardless of the existence of the gap, the shaft as a whole is substantially in contact with the drive roller at any angular position on the circumferential surface, so that smooth rotation is obtained, vibration during winding is reduced, and winding starts. This makes it possible to achieve high-speed rotation, increase efficiency, and reduce operating noise.
[0012]
Further, when the winding on the roll is completed, the roll can be easily pulled out from the shaft by eliminating the radially outward pressure on the expandable body, that is, the leaf.
Also, since the side edge at the edge of the leaf is in contact with the opposite side of the adjacent leaf in the circumferential direction, the axially opposed surface always abuts between the adjacent leaves regardless of the expansion and contraction of the winding shaft. In this portion, there is an effect that no gap remains even when the diameter of the winding shaft is expanded.
[0013]
According to the invention described in claim 2, in the invention described in claim 1, each of the leaves divided in the circumferential direction is integrated over the entire length in the axial direction, and the coreless winding for a continuous sheet is characterized in that: A spindle is provided.
[0014]
To explain the operation and effect of the second aspect of the present invention, the leaves are divided in the circumferential direction, but each leaf is one in the longitudinal direction over its entire length. Therefore, the structure is simple and the number of parts is small, which is advantageous in cost.
[0015]
According to a third aspect of the present invention, there is provided the continuous sheet coreless winding shaft according to the first aspect, wherein each leaf is divided into a large number in the axial direction.
[0016]
In order to explain the function and effect of the invention of claim 3, the leaf is divided in the circumferential direction and also has a divided structure in the axial direction. Since the structure is divided in the axial direction, mounting is performed for each leaf, and the number of fitting parts (parts requiring core alignment) per piece is reduced. This is advantageous in that the mounting work becomes easy and the mounting work becomes easy.
[0017]
According to a fourth aspect of the present invention, in the invention of the first aspect, a material layer having low adhesion to a resin film is formed on an outer surface of each leaf. A coreless winding shaft is provided. A coreless winding shaft for a continuous sheet is provided, wherein the shaft has a low-adhesion material layer on a contact surface of a resin film.
[0018]
The function and effect of the invention of claim 4 can be described as follows. Even when a film having high adhesion such as polyethylene is wound by a winding shaft due to a low-adhesion material layer on a leaf surface, the contact surface with the film can be obtained. Since the shaft surface is made of a low-adhesion material, the roll can be easily separated from the shaft.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the winding shaft of the present invention will be described with reference to the drawings. The winding shaft of the present invention is based on a leaf-type pneumatic expansion / contraction winding shaft, and its basic structure will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a winding shaft when the leaf is expanded, and FIG. 2 is a cross-sectional view showing the winding shaft when the leaf is reduced. In FIG. 1, reference numeral 1 denotes a winding shaft. The winding shaft 1 has an expansion body 3 made of a rubber elastic tube which is expanded by injecting air into a cylindrical shaft body 2 and contracted by extracting air. A plurality of lugs are provided, are loosely fitted in lug holes 4 formed in the shaft body 2, and are advanced and retracted in the radial direction of the shaft body 2 via the lug plate 5 by the expansion or contraction action of the expansion body 3. A plurality of (four) leaves 7 extending in the axial direction and having an arc-shaped cross section are individually fixed to the lugs 6 in the respective rows. The inflation of the inflatable body 3 is caused by the injection of air, and the expansion causes the lug 6 to move outward in a radially outward direction. As a result, the leaf 7 is radially outwardly expanded. This expanded state is shown in FIG. 1. At this time, each leaf 7 is located on the circumference of a complete circle, and in this state, the roll-like winding of a sheet such as a wrap film is performed. In the expanded state, the leaves 7 are located on the circumference, but the edges between the leaves 7 adjacent in the circumferential direction face each other with a gap L therebetween. The gaps L are arranged at equal intervals (every 90 degrees) in the circumferential direction.
[0022]
The discharge of the air from the expansion body 3 causes the plurality of expansion bodies 3 to contract through the lugs 6, and the contraction causes the leaves 7 to be reduced to the solid line positions via the lugs 6 moved backward from the advanced position. As shown in FIG. The roll can be pulled out using the diameter difference between the diameter-expanded state in FIG. 1 (the outer circumference of the winding shaft 1 in the diameter-expanded state is indicated by a dashed line C in FIG. 2) and the diameter-reduced state in FIG. Injection and discharge of air to and from the inflatable body 3 are performed through a suction port (not shown) provided at one end of the winding shaft 1. As described above, the leaf-type winding shaft is configured such that the gap groove (L) at the side edge portion of each adjacent leaf 7 is enlarged when the leaf 7 is wound up. The shaft body 2 of the winding shaft 1, the lug 6 including the lug plate 5, and the leaf 7 are made of metal. The leaf 7 fixed to the lug 6 may be fixed separately from the lug 6 by a fixing means such as a screw, or may be formed integrally with the lug 6.
[0023]
Next, the structure of the leaf 7, which is a feature of the present invention, will be described with reference to FIG. FIG. 3 shows an overall perspective view of the winding shaft 1 on the lower side, and one leaf 7 thereof in a perspective view on the upper side. Both edges along the axial direction of each leaf 7 are alternately formed into a plurality of projecting edges 8 and retreating edges 9 equally divided in the axial direction, and the projecting edges 8 have projecting sides extending in the axial direction. 8A and a protruding side 8B intersecting with the protruding side 8A. The retreating edge portion 8 has a base 9A extending in the axial direction and both retreating sides 9B intersecting with the base 9A. That is, the edges of the axial direction of each leaf 7 are shifted alternately in the circumferential direction along the longitudinal axis of the winding shaft 1, the shape of a U-shaped concave-convex shape as shown in FIG. 5 I have. The opposing edges between the circumferentially adjacent leaves 7 are in a complementary relationship, and in the first embodiment shown in FIGS. And the retreating edge 9 are in a relationship of being inserted into each other. Thus, the gap L is formed between the leaf 7 adjacent when expanded of the winding shaft 1 is shifted in the opposite direction alternately along the axial direction of the winding shaft 1 as shown in FIGS. 3 and 5 .
[0024]
Further, in the embodiment of the leaf shown in FIG. 3, both projecting side edges 8B of the projecting edge portion 8 and both receding side edges 9B of the receding edge portion 9 extend along the circumferential direction of the leaf 7. . In other words, both projecting sides 8B of the projecting edge 8 are orthogonal to the projecting sides 8A extending in the axial direction, and both receding sides 9B of the retreating edge 9 extend in the axial direction. It is formed to be orthogonal to the flattened bottom 9A. By forming the side edges 8B, 9B of the protruding edge portion 8 and the retreating edge portion 9 in this manner, even when the leaf 7 is expanded, a gap groove is not formed between the side edges 8B, 9B. It is configured as follows. That is, between the leaves adjacent in the circumferential direction, the side edges 8B and 9B always maintain a close (or contact) relationship regardless of the expansion and contraction of the winding shaft, and a substantial gap is formed in this portion. There is no.
[0025]
The winding drive of the winding shaft 1 that is driven to rotate at the time of winding is performed by appropriate means. As shown in FIG. The outer peripheral surface of the take-up shaft 1 is pressed against the outer peripheral surface of the rollers 10 and 10 ′ (one of them (for example, the roller 10) is a driving roller) by pressure and is pressed by the pressing roller 11. The take-up shaft 1 is rotationally driven via the rotational driving force of the drive roller 10, and the sheet such as the wrap film 12 sent around the take-up shaft 1 as shown by an arrow is wound. Numeral 14 indicates a state in which the sheet has been wound on a roll having a predetermined outer diameter, 1 'indicates the position of the winding shaft at that time, and 11' indicates the position of the pressing roller when the roll is completed. When the sheet is wound by being pressed against the winding rollers 10 and 10 ', there are four gaps L between the leaves along the circumferential direction in one cross section as shown in FIG. However, the presence of the gap L does not cause the shape to be lost when the sheet is wound into a roll. That is, FIG. 5 is a distribution of the gap L between the leaves in the axial direction at the time of expansion of the winding shaft 1 in the first embodiment of Figures 1-3 showing schematically. In this embodiment, the gap L is circumferentially alternately shifted in the opposite direction along the axis 1 'of the winding shaft 1. In other words, the gap L between the leaves does not extend over the entire length of the axis of the winding shaft 1. Therefore, as shown in FIG. 4, when the winding shaft 1 is brought into circumferential contact with the rollers 10, 10 'to wind up the sheet 12, the winding shaft 1 always has a gap L between leaves in a cross section. However, since this gap L is not parallel to the axis over the entire length of the winding shaft 1, the winding shaft 1 contacts the winding rollers 10, 10 'on the circumferential surface when viewed in the axial direction of the winding shaft 1. It always has a part. Therefore, at this portion of the leaf 7, the winding shaft 1 comes into pressure contact with the roll surfaces of the drive rolls 10 and 10 'substantially by circles, and a gap extending between the leaves over the entire length in the axial direction is formed. Unlike the conventional leaf-type winding shift, there is substantially no vibration caused by the gap groove L and smooth rotation can be obtained, so that high-speed winding can be performed from the beginning of winding, and there is no problem of noise. .
[0026]
A laminating tape formed by impregnating a mesh-like cloth such as a glass fiber cloth with a resin having a low coefficient of friction such as poly (4) ethylene and having a low adhesive property is applied to the winding surface of each leaf 7 to form a laminate. It is preferable to keep it. Thereby, the resin film sheet is lightly adhered to the winding surface of the metallic leaf 7 which is easily adhered to the resin film sheet having adhesiveness, and is easily detached when a detaching force is applied. Then, the roll of the resin film sheet having the adhesive property wound on the winding surface of the leaf can be easily extracted from the winding shaft when the leaf 7 is reduced.
[0027]
Further, the outer surface of each leaf 7 is covered with an outer layer tube made of the same material as that of the laminated tape, and the wrapping surface of the metallic leaf 7 which is easily adhered to the resin filter having adhesiveness as in the case of the laminated tape. The resin sheet is lightly adhered and is configured to be easily detached when a detaching force is applied, and the roll of the adhesive resin film sheet wound around the winding surface of the leaf 7 is leafed. It may be configured such that it can be easily removed from the take-up shaft when the size 7 is reduced. As described above, even when the outer tube made of the same material as that of the laminated tape is covered on the winding surface of the leaf 7, the outer tube hardly becomes linear at the position of the gap groove L. The fact that the outer tube is unlikely to bite into the gap groove L is the same as that described for the winding of the resin film sheet.
[0029]
6 to 8 show another embodiment. In the first embodiment, as shown in FIG. 3, the leaves are divided only in the circumferential direction, and in the axial direction of the winding shaft 1, the leaves are integrally formed over the entire length thereof. On the other hand, in the embodiment of FIGS. 6 to 8, the leaf 70 is divided not only in the circumferential direction but also in the axial direction of the winding shaft 1. FIG. 8 is a perspective view showing a dividing structure of the leaves 70 in the circumferential direction and the axial direction. 7, the plates 50 are arranged at equal intervals in the circumferential direction on the inner periphery of the shaft body 20, and the guide portions 52 are fixed to the corresponding plates 50 by screws 53 as shown in FIG. The shaft body 20 has a slot 20-1 in which the guide portion 52 is fitted slidably in the radial direction and substantially without backlash in the axial direction. The leaf 70 is fixed to the guide part 52 by a screw 71. In FIG. 7, reference numeral 30 denotes an inflatable body such as a rubber tube, the outer periphery of which is in contact with the abutment plate 50.
[0030]
In this embodiment, the expansion of the expansion body 30 is transmitted to the corresponding leaf 70 via the abutment plate 50 and the guide portion 52, and the leaf 70 assumes a position that is expanded radially outward. FIG. 7 shows an expanded state of the winding shaft 1. In the enlarged diameter state, a gap L is formed between the leaves 70 circumferentially adjacent to each other, but the gap L is alternately opposite in the axial direction of the winding shaft as in the first embodiment. Since the gap L does not extend over the entire length of the axis of the winding shaft, the winding shaft 1 always has a circumferential surface in contact with the driving roller along the axial direction. Similarly, when the wrap film is wound on a roll, the occurrence of streak-like projections on the inner circumference of the roll can be reduced, smooth rotation from the start of winding can be ensured, and these actions and effects can be performed in other ways. It is similar to that of the form.
[0031]
In the second embodiment shown in FIGS. 6 to 8, the leaves 70 are divided not only in the circumferential direction but also in the axial direction, and the leaf 70 is attached to the shaft body 20 one by one. Since it is easy to control the accuracy of the shaft holes 53 and 71, there is an operation and effect that facilitates manufacture and assembly.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a winding shaft according to a first embodiment of the present invention in a state where the diameter of the winding shaft is enlarged.
FIG. 2 is a cross-sectional view of the winding shaft of FIG. 1 in a reduced diameter state.
FIG. 3 is a schematic perspective view showing the winding shaft of FIG. 1 together with one leaf.
FIG. 4 is a diagram schematically illustrating a roll winding method for a sheet such as a wrap film using a winding shaft according to the present invention.
FIG. 5 is a diagram schematically showing a shape of an edge of a leaf in a winding shaft according to the present invention.
FIG. 6 is a partial axial sectional view of a winding shaft according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view of the winding shaft of the present invention, taken along line VII-VII in FIG. 6;
FIG. 8 is a schematic perspective view showing the winding shaft according to the second embodiment with leaves partially removed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Winding shaft 2 ... Shaft 3 ... Expansion body 5 ... Lug plate 6 ... Lug 7 ... Leaf 8 ... Protruding edge 9 ... Retreating edge 10, 10 '... Winding roller 12 ... Wrap film 20 ... Shaft 20 -1 ... slot 30 ... expansion body 50 ... contact plate 52 ... guide part 70 ... leaf 71 ... screw L ... gap groove

Claims

It is for a continuous sheet as a food packaging film, and comprises a tubular shaft, an expanded body in the tubular shaft, and a plurality of leaves outside the tubular shaft, each of the plurality of leaves being in the axial direction. And the plurality of leaves are divided and arranged so as to occupy respective angular ranges in the circumferential direction, and the inflatable body and the leaf are so arranged as to expand the leaf radially outward when the inflatable body is inflated. A cooperating means for cooperating is provided.In this leaf expanded state, the continuous sheet is wound around the outer periphery of the continuous sheet in a roll shape, and the continuous sheet can be removed by contraction of the expansion body. Because of the roll-shaped winding, the winding shaft is rotated by contact with the driving roller through the continuous sheet, and both edges in the rotation direction of each leaf are formed with a protruding side or base extending in the axial direction. Circumference And the side edges extending in the opposite direction are formed alternately along the axis, and the opposite side edges of a pair of circumferentially adjacent leaves are complementary to each other, and the side edges at each side edge of each leaf. A coreless winding shaft for a continuous sheet, which is in contact with opposing sides of adjacent leaves in the circumferential direction.

2. The coreless winding shaft for a continuous sheet according to claim 1, wherein the leaves divided in the circumferential direction are integrated over the entire length in the axial direction.

2. The coreless winding shaft for a continuous sheet according to claim 1, wherein each leaf is divided into a plurality of parts also in an axial direction.

2. The coreless winding shaft for a continuous sheet according to claim 1, wherein a material layer having low adhesion to a resin film is formed on an outer surface of each leaf.