| 摘要 |
<p>1474496 Seaming ALUMINIUM CO OF AMERICA 4 March 1975 [14 March 1974] 8945/75 Heading B3J [Also in Division B8] A container wall is scored to provide on at least partially removable panel by applying a secondary indenter outboard of and substantially co-extensive with a primary score line before an indenter forming the score line has penetrated to 50% of its ultimate penetration, the spacing between the centre lines of the indenters being no more than 0À04 inches and the ultimate penetration of the secondary indenter being no more than 75% of the ultimate penetration of the primary indenter. As shown, pressure is applied outboard and inboard of the primary score by secondary indenters 12 on each side of a primary indenter 14, of greater projection to provide the lead. The spacing between indenters is 0À025-0À04 inches or less. The width 16 of the primary indenter 14 is preferably no more than 0À002 inches and the thickness of metal remaining beneath the indenter 14 may be no more than 0À003, e.g. 0À0015, inches, but widths of 0À0025-0À003 are referred to and a residual of 0À0035 and 0À004 inches. The face angles 20 may be 30-90 degrees but preferably 50-60 degrees. Laminate, layered or coated walls may be scored. The face width 18 of the secondary indenters 12 may be 0À0015-0À002 and that 16 of the primary indenter 14, 0À0005-0À0010. Specification 1,164,179 is referred to.</p> |
