Abstract This disclosure relates to the formation of a can body having at least one necked-in end portion wherein at least the end portion of the can body is of a lapped construction with a deformable bonding material therein. It is customary to neck-in ends of can bodies utilizing a necking die with a floating center post. The clearance in such die construction takes into consideration the extra thickness of the side seam. It is now proposed to make the clearance between the die ring and the center post such that when the necking in occurs, the side seam will be compressed, thereby assuring side seam end portions of a uniform thickness. It is also proposed to effect a reduction in the thickness of the deformable bonding material which will provide increased seam strength, better creep resistance, and last, but not least, superior double seaming latitude because of uniformity and consistency of dimensions.
A method forming a can body having a necked-in end, said necked-in end having a bonded lapped seam of a predetermined uniform thickness, said method comprising the steps of forming a can body having a side seam of which at least one end portion is of a lapped construction with a deformable bonding material therein, and engaging said one end portion and simultaneously reducing the diameter of said one end portion and radially compressing said end portion side seam to said predetermined uniform thickness by deforming the bonding material while the wall thickness of the remainder of said can body end portion remains substantially undiminished.
Claim 2
Independent Claim
105 words
A method forming a can body having a necked-in end, said necked-in end having a bonded lapped seam of a predetermined uniform thickness, said method comprising the steps of forming a can body having a side seam of which at least one end portion is of a lapped construction with a deformable bonding material therein, and engaging said one end portion and simultaneously reducing the diameter of said one end portion and radially compressing said end portion side seam to said predetermined uniform thickness by deforming the bonding material while the wall thickness of the remainder of said can body end portion remains substantially undiminished.
Claim 3
Dependent Claim
51 words
The method of claim 1 wherein said necking-in is accomplished by forcing said one end portion around a post and into an externally confined space of a diameter equal to the diameter of said plug plus three times the can body wall thickness plus the predetermined thickness of said bonding material.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein there is a reduction in thickness of the deformable bonding material below the customary thickness thereof.