STRUCTURE OF OPENING CURL PART OF BOTTLE TYPE CAN

To provide a structure of an opening curl part of a bottle type can, that is less likely to damage a tamper-evidence property via excellent form maintainability with respect to a load from above.SOLUTION: A curl part 10 comprises an inner peripheral wall part 16, an upper end R part 17, an outer peripheral wall part 20, a lower end R part 21, a folding piece part 22, and a tip edge part 23. An inclined wall part 15 where an outer diameter is gradually increased by downwardly connecting to a screw from the inner peripheral wall part 16. A retreat surface 24 for which a curvature radius R2 on a cross-section when being cut on a flat face passing through a center axis line O of a neck part, whose curvature center P2 is present outside the neck part is larger than another curvature radius R1 of the lower end R part 21 is provided, while extending downward from a lowermost end part 25 at which the folding piece part 22 comes into contact with a connecting part from the inner peripheral wall part 16 to the inclined wall part 15.SELECTED DRAWING: Figure 3 【課題】上方からの荷重に対する形態の維持性に優れることによりタンパーエビデンス性を損なうことの少ないボトル型缶の開口カール部の構造を提供する。【解決手段】カール部１０は、内周壁部１６と、上端Ｒ部１７と、外周壁部２０と、下端Ｒ部２１と、折り込み片部２２と、先端エッジ部２３とを有し、内周壁部１６から下側にねじ部に繋がりかつ下側で外径が次第に増大する傾斜壁部１５が設けられ、内周壁部１６から傾斜壁部１５に繋がる部分に、折り込み片部２２が接触する最下端の部分２５から下側に延びるとともに、口頸部の外側に曲率中心Ｐ2がありかつ口頸部の中心軸線Ｏを通る平面で切断した場合の断面における曲率半径Ｒ2が下端Ｒ部２１の曲率半径Ｒ1より大きい退避面２４が設けられている。【選択図】図３