Arrangement and method for manufacturing can lids

Patent metadata

Field	Value
Publication number	US-9242289-B2
Application number	US-201113200744-A
Country	US
Kind code	B2
Filing date	Sep 29, 2011
Priority date	Oct 4, 2010
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

In a method according to the invention for the manufacture of tear notches ( 22 ) in can lids ( 11 ), the can lid ( 11 ) is subjected in the press tool ( 10 ) to a laser engraving during which the desired tear notch ( 22 ) is generated. The laser ablation process occurs preferably, with the press tool ( 10 ) closed, within a time period of less than 30 ms. During this time, the focal spot ( 27 ) of the laser beam ( 26 ) is moved over the whole desired contour of the tear notch ( 22 ) so that an uninterrupted groove-like cavity is formed. With the use of laser engraving in the press tool, the mechanical wear of the press tool and of the press molds can be minimized and in this way the tool operating life can be increased. In particular, the manufacture of can lids with consistently high quality is ensured.

First claim

What is claimed is:

1. Press tool ( 10 ) for the manufacture of a can lid ( 11 ) which can be ripped open, comprising:
the press tool ( 10 ) is a stage tool including several press stages ( 16 , 17 , 18 );
a first tool part ( 14 ) and a second tool part ( 15 ) provided with complementary molds for transforming therebetween a metal sheet or a metal strip into the can lid ( 11 ) in one or several operating strokes of the press tool ( 10 ), each stroke causing a cooperative opening and closing of the first tool part ( 14 ) and the second tool part ( 15 );
a laser head ( 21 ) arranged in one of the tool parts ( 14 , 15 ) set up to generate a laser focal spot ( 27 ) of a laser beam ( 26 ) on the can lid ( 11 );
the laser beam ( 26 ) for forming by laser engraving a tear notch ( 22 ) into the can lid ( 11 );
the laser head ( 21 ) is arranged in one of the press stages ( 18 ) of the stage tool ( 10 ) which is not assigned any deforming operation; and,
means ( 25 ) for moving the laser focal spot ( 27 ) of said laser beam ( 26 ) along the contour of the tear notch ( 22 ) to be formed into the can lid ( 11 ).

2. Press tool ( 10 ) according to claim 1 , characterized by, the means ( 25 ) for moving the laser focal spot ( 27 ) comprises at least one mirror ( 29 ) which is movable by a drive means ( 31 ).

3. Press tool ( 10 ) according to claim 1 , characterized by, the laser head ( 21 ) is arranged in the first tool part ( 14 ) which is stationary during press operation.

4. Press tool ( 10 ) according to claim 1 , characterized by, the laser head ( 21 ) is connected, via a mirror beam path ( 36 ) to the laser beam ( 26 ) which is arranged outside the press tool ( 10 ).

5. Press tool ( 10 ) according to claim 4 , characterized by, the laser head ( 21 ) is arranged in the second tool part ( 15 ) which is movable and the mirror beam path ( 36 ) extends parallel to the direction ( 20 ) of movement of the second tool part ( 15 ).

6. Press tool ( 10 ) according to claim 1 , characterized by, one of the first tool part ( 14 ) and second tool part ( 15 ) is movable, said press tool ( 10 ) further including a resiliently supported tool holder ( 43 ) for temporarily holding the can lid ( 11 ) affixed to and resiliently supported by a spring means ( 44 ), the spring means ( 44 ) affixed to said one movable first tool part ( 14 ) or second tool part ( 15 ).

7. Press tool ( 10 ) according to claim 1 , characterized by, the laser head ( 21 ) includes means for adjusting at least one of the focusing of the laser beam ( 26 ), the laser treatment duration, the speed of movement of the focal point ( 27 ), and the cooling of the can lid ( 11 ), whereby the brittleness of the can lid ( 11 ) at the tear notch ( 22 ) can be adjusted.

8. Press tool ( 10 ) for the manufacture of a can lid ( 11 ) which can be ripped open, comprising:
a first tool part ( 14 ) and a second tool part ( 15 ) provided with complementary molds for transforming therebetween a metal sheet or a metal strip into the can lid ( 11 ) in one or several operating strokes of the press tool ( 10 ), each stroke causing a cooperative opening and closing of the first tool part ( 14 ) and the second tool part ( 15 );
a laser head ( 21 ) arranged in one of the tool parts ( 14 , 15 ) set up to generate a laser focal spot ( 27 ) of a laser beam ( 26 ) on the can lid ( 11 );
the laser beam ( 26 ) for forming by laser engraving a tear notch ( 22 ) into the can lid ( 11 );
the laser head ( 21 ) is in operative synchronization with the cooperative opening and closing of the first tool part ( 14 ) and second tool part ( 15 );
means ( 25 ) for moving the laser focal spot ( 27 ) of said laser beam ( 26 ) along the contour of the tear notch ( 22 ) to be formed into the can lid ( 11 ); and,
the operative synchronization of the laser head ( 21 ) is arranged so the means ( 25 ) for moving the laser focal spot ( 27 ) is operative for moving the laser focal spot ( 27 ) along the desired contour of the tear notch ( 22 ) only when the press tool ( 10 ) is at rest.

9. Press tool ( 10 ) according to claim 8 , characterized by, the means ( 25 ) for moving the laser focal spot ( 27 ) comprises at least one mirror ( 29 ) which is movable by a drive means ( 31 ).

10. Press tool ( 10 ) according to claim 8 , characterized by, the laser head ( 21 ) is arranged in the first tool part ( 14 ) which is stationary during press operation.

11. Press tool ( 10 ) according to claim 8 , characterized by, the laser head ( 21 ) is connected, via a mirror beam path ( 36 ) to the laser beam ( 26 ) which is arranged outside the press tool ( 10 ).

12. Press tool ( 10 ) according to claim 11 , characterized by, the laser head ( 21 ) is arranged in the second tool part ( 15 ) which is movable and the mirror beam path ( 36 ) extends parallel to the direction ( 20 ) of movement of the second tool part ( 15 ).

13. Press tool ( 10 ) according to claim 8 , characterized by, one of the first tool part ( 14 ) and the second tool part ( 15 ) includes a stamping rib ( 46 ) which follows the contour of tear notch ( 22 ) to form a recess ( 45 ) in the can lid ( 11 ).

14. Press tool ( 10 ) according to claim 8 , characterized by, the laser head ( 21 ) includes means for adjusting at least one of the focusing of the laser beam ( 26 ), the laser treatment duration, the speed of movement of the focal point ( 27 ), and the cooling of the can lid ( 11 ), whereby the brittleness of the can lid ( 11 ) at the tear notch ( 22 ) can be adjusted.

Assignees

• Blei Klaus
• Röver Markus
• Schuler Pressen Gmbh

Inventors

• Blei Klaus
• Röver Markus

Classifications

• B23K2201/125

  Operations & Transport · mapped topic

• B65D17/24

  Operations & Transport · mapped topic

• B23K26/364

  for making a groove or trench, e.g. for scribing a break initiation groove · CPC title

• B21D51/383 Primary

  scoring lines, tear strips or pulling tabs · CPC title

• B23K26/0093

  combined with mechanical machining or metal-working covered by other subclasses than B23K · CPC title