US 5,287,718 A · Curl forming method for a can end

Abstract

A curl forming method for a can end which enables satisfactory curl formation in a thin can end without occurrence of wrinkles and without occurrence of scratches on internal surfaces of the can end and which can make a can end thinner. A punched can end is pressed and bended from an open end of annular flange and an opposite side by a primary forming die having an inner diameter larger than a final curl diameter by 0 to 2.0 mm to effect a primary forming, and then it is pressed and bended from the side of the flange open end by a secondary forming punch having a forming surface 14 having a final shape of a curl.

Drawings

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Drawings

Claims1

Dependent claims

A curl forming method of a can end for forming a curl on a flange end of the can end for attaching the can end on a can body, said method comprising the steps of:

supplying a can end having a flange between a primary forming punch and a primary forming pad arranged opposite to said primary forming punch;
holding securely said flange of said can end by said primary forming punch and said primary forming pad such that an extreme end of said flange is protruded radially outwardly from an outer peripheral portion of said primary forming punch and said primary forming pad;
a primary forming step of forming a primary curl on the extreme end of said flange by forcing said flange into a die hole of a primary forming die from a side opposite to an open end of said flange, while holding said flange by said primary forming punch and said primary forming pad, said primary forming die being movably arranged relative to the outer peripheral portion of said primary forming pad, said die hole being larger by 0 to 2.0 mm than a diameter of a final curl of said extreme end of said flange, so that the extreme end is inwardly bent to form a primary curl on the flange during the relative movement between the primary forming die and the primary punch and pad assembly;
supplying the can end formed with the primary curl on said flange between a secondary forming pad and a secondary forming die arranged opposite to said secondary forming pad;
holding securely said flange of said can end by said secondary forming pad and said secondary forming die such that the extreme end of said flange is protruded radially outwardly from the outer peripheral portion of said secondary forming pad;
and
a secondary forming step of forming a final curl shape on the extreme end of curl on said flange by which a secondary forming punch movably arranged relative to the outer peripheral portion of said secondary forming pad, and having a forming surface matched to said final curl shape of the flange end, is relatively moved substantially orthogonally to the plane of the can end from the open side of the primary curl of said can end toward the flange end, whereby the extreme end of the flange end is pressed and bent by said secondary forming punch to form the extreme end of the flange end into the final curl shape.

4 more elements

Dependencies are inferred from the claim text.

Description2,100 words

Summary1,092 words

#(1) Field of the Invention

#The present invention relates to a curl forming method for a can end in a can end manufacturing process, and more specifically, to a curl forming method for a can end capable of providing curl formation for a thin can end without inducing wrinkles.

#(2) Description of the Prior Art

Brief description of the drawings2 figures

#FIGS. 1(A) and (B) are schematic views showing a primary forming step, and FIGS. 1(C) and (D) are schematic views showing a secondary forming step.

#FIG. 2 is a schematic view of a conventional curl forming apparatus.

Detailed description971 words

#Embodiments of a curl forming method for a can end according to the present invention will be described with reference to the drawings.

#The curl forming apparatus for carrying out the method for the present embodiments comprises a primary forming die assembly for carrying out the primary forming, and a secondary forming die assembly for carrying out the secondary forming. As shown in FIGS. 1(A) AND (B), a primary forming die assembly 1 has a vertically movable primary forming punch 2 and a primary forming pad 3. A primary forming die 4 having a die hole 5 having an inner diameter which is larger than a final curl diameter by 0 to 1 mm is fitted in the outer periphery of the primary forming pad 3. The primary forming step is carried out by the primary forming die assembly in the following manner.

#When a can end (shell) 6 punched by a press in the previous step is supplied onto the primary forming die 4 by a suitable supplying device with an open end of an annular flange thereof directed upward, the primary forming punch 2 moves down. The can end 6 is held between the punch 2 and the primary forming pad 3 and forced into the die hole 5 whereby the flange end is inwardly forced in by the primary forming die 4 from the side opposite to the flange open end relatively. Thereby, the flange end is raised upwardly as shown in FIG. 1(B) and subjected to the primary forming up to the range wherein the outer diameter thereof is larger than the final curl diameter by 1.0 mm or less.

Facts

Application

08/004,499Filed 14 Jan 1993 · continuation

Priority

JP 3-1497316 Jan 1991

Granted

22 Feb 1994

Term ended

7 Jan 2012

Estimated · how

Pre-1995 term; greater of 17 years from grant or 20 years from filing when eligible. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification3 codes

B21D 19/12
Flanging or other edge treatment, e.g. of tubes: edge-curling
B21D 51/38
Characterised by the use of the objects: making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends;…
B21D
Working or processing of sheet metal or metal tubes, rods or profiles

Curl forming method for a can end

Life of this patent

Curl forming method for a can end

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims1

Description2,100 words

Drawings

Classification3 codes

Life of this patent

Description2,100 words