WO1999008819A1 - Easy open can ends - Google Patents
Easy open can ends Download PDFInfo
- Publication number
- WO1999008819A1 WO1999008819A1 PCT/GB1998/002409 GB9802409W WO9908819A1 WO 1999008819 A1 WO1999008819 A1 WO 1999008819A1 GB 9802409 W GB9802409 W GB 9802409W WO 9908819 A1 WO9908819 A1 WO 9908819A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- score
- sidewall
- planar
- angle
- outer sidewalls
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D51/00—Making hollow objects
- B21D51/16—Making hollow objects characterised by the use of the objects
- B21D51/38—Making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends; Making closures
- B21D51/383—Making inlet or outlet arrangements of cans, tins, baths, bottles, or other vessels; Making can ends; Making closures scoring lines, tear strips or pulling tabs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D17/00—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
- B65D17/28—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
- B65D17/404—Details of the lines of weakness
Definitions
- This invention relates to easy open can ends and to score dies for manufacturing such easy open ends.
- Easy open ends have a score track defining an operable portion or panel, which can be operated by a tab or other opening mechanism. This principle is the same whether the can end is a full aperture easy open end (normally used for foodstuffs), a pull tab beverage end, or the more modern stay-on tab commonly used for drinks cans.
- a method of producing an operable portion in an easy open can end formed of a metallic substrate coated with a polymer film material comprising the steps of contacting the can end with a score die and an anvil die, the score die comprising a truncated "V" shaped projection having a planar inner sidewall adapted to produce a planar score sidewall adjacent the operable portion, a planar outer sidewall adapted to produce a planar score sidewall adjacent the remainder of the can end, and a generally horizontal flat land portion adapted to form the base of the score, characterised in that each of the inner and outer sidewalls is at an angle of between 15° and 60° to the longitudinal axis of the projection, there being a difference of at least 15° between the angles of the inner and outer sidewalls.
- the steeper of the inner or outer sidewalls preferably lies at an angle of between 15° and 25° to the longitudinal axis, and the shallower of the inner or outer sidewalls at an angle of between 45° and 60° to the longitudinal axis.
- the included angle between the inner and outer sidewalls is at least 60°.
- the steeper of the inner or outer sidewalls lies at an angle of about 15° to the longitudinal axis, and the shallower of the inner or outer sidewalls at an angle of about 50° to the longitudinal axis.
- the outer sidewall lies at a steeper angle than the inner sidewall, although this may vary depending on individual end presses or different sizes of easy open end.
- the invention further resides in a score die for producing an operable portion in an easy open can end, the score die comprising a truncated "V" shape projection having a planar inner sidewall adapted to produce a planar score sidewall adjacent the operable portion, a planar outer sidewall adapted to produce a planar score sidewall adjacent the remainder of the can end, and a generally horizontal flat land portion adapted to form the base of the score, characterised in that each of the inner and outer sidewalls is at an angle of between 15° and 60° to the longitudinal axis of the projection, there being a difference of at least 15° between the angles of the inner and outer sidewalls.
- an easy open can end formed of a metallic substrate coated with a polymer film material, and including a panel portion having an operable portion defined by a score line, the score line comprising a planar inner score sidewall adjacent the operable portion, a planar outer score sidewall adjacent the remainder of the panel portion, and a generally horizontal flat land portion therebetween forming the base of the score, characterised in that each of the inner and outer sidewalls is at an angle of between 15° and 60° to an axis perpendicular to the can end, there being a difference of at least 15° between the angles of inner and outer sidewalls.
- the metallic substrate is an aluminium alloy.
- Fig.l is a schematic sectional view of a conventional score die producing a score track on an easy open can end
- Figs. 2 and 3 are schematic sectional views of score dies according to the present invention.
- Fig.4 is a graph showing the incidence of angel hairs obtained from the score dies of Figs. 1 to 3.
- a can end 1 comprises a metallic substrate 4, typically of aluminium, with a film 5, typically of polyester, laminated to the upper surface 6 thereof.
- a similar film 7 is laminated to the lower surface 8 of the can end.
- the can end is typically as described in our PCT application No. W093/17864.
- the score die comprises a "V" shaped projection 9 having a first sidewall 10, a second sidewall 11, and a horizontal land portion 12 therebetween.
- the first and second sidewalls are each inclined at an angle of approximately 25° to the longitunal axis of the projection 9.
- the "included angle" of the score die is therefore approximately 50°.
- Score dies such as these are frequently given a surface coating (not shown) in order to increase the wear resistance of the score die.
- the can end 1 is pressed between the score die 2 and an anvil 13 to form the score 3, defining a tear panel 14 within the remainder of the central panel 15 of the can end.
- the score 3 comprises an inner sidewall 16 adjacent the tear panel and formed by the first sidewall 10 score die, and an outer sidewall 17 adjacent the panel 15 and formed by the second sidewall 11 of the score die.
- the inner and outer sidewalls 16 and 17 are formed at substantially the same angles as the first and second sidewalls 10 and 11 of the score die.
- the base 18 of the score extends between the sidewalls 16 and 17, and the portion 19 between the base 18 and the lower surface 8 of the can end is known as the "score residual".
- the tear panel 15 When the opening mechanism (not shown) of the can end is operated, the tear panel 15 is pressed down with respect to the panel 15, to cause the score 3 to break. The score will tend to separate along a line extending through the score residual from either a point 20 at the intersection of the base 18 and inner sidewall 16, or a point 21 at the intersection of the base 18 and outer sidewall 17. As the tear panel separates from the panel 15 along the length of the score, the fracture (shown schematically at 22) may switch one or more times between points 20 and 21. This may cause the film 23 in the base of the score to become detached, forming a sliver of film known as an "angel hair".
- Fig.2 shows how the score die 2 and hence the score 3 is adapted to reduce this problem.
- the first sidewall 10 of the score die, and hence the inner sidewall 16 of the score is at a first angle A to the longitudinal axis of the projection 9.
- the angle A is approximately 45°.
- the second sidewall 11, and hence the outer sidewall 17 of the score is at a second angle B to the longitudinal axis.
- this angle B is only 25°.
- the difference in angles urges the fracture 22 to stay associated with the point 21 (i.e. adjacent the steeper score sidewall) throughout the length of the score.
- the incidence of angel hairs is reduced or even eliminated.
- Fig.3 shows the opposite arrangement in which the inner sidewall 16 of the score is at the relatively steep angle (i.e. 25°) and the outer sidewall 17 is at the relatively shallow angle (i.e. 45°).
- This arrangement will tend to be appropriate where it is preferable to try to associate the fracture 22 with the point 20, i.e. adjacent the inner sidewall 16.
- Table 1 below shows how a range of score dies, with different angles A and B, have been tested.
- the samples were all subjected to a corner treatment, such as a tumbling process which rounds the sharp edges of the score dies prior to use.
- Samples A to C were prior art designs in accordance with Fig.l, samples D to G and J to M were similar to that of Fig.2, whilst sample H was generally in accordance with Fig.3.
- the graph of Fig. shows how these samples behaved in producing angel hairs, with the number of angel hairs observed being shown as a percentage.
- the asymmetric score tracks of samples D, E, F, G, J, K, L and M showed a marked reduction in angel hairs over the conventional score track of samples A to C.
- Sample H showed an actual increase in angel hair percentage, but this is believed to be because the natural inclination of the easy open ends being tested was to fracture around the edge of the panel 15 rather than the tear panel 14. It is believed that other easy open ends of a different diameter or design, or manufactured with different equipment, may have a natural predisposition to fracture adjacent the panel 15 and hence the design of Fig.3 may offer improvements in such cases. Simple tests will be able to demonstrate whether, for any particular type of can end, the design of Fig.2 or that of Fig.3 will give better results.
- Can ends produced from a prior art score die such as sample A were compared with those from a score die in accordance with the invention, such as sample K, in respect of break and tear force, and coating integrity.
- Score break and score tear performance is shown in Table 2 below with the figures being shown in lbf (kgf) .
- the break and tear force figures for the ends made in accordance with the invention were well within the accepted specification of 2.5 to 4.5 lbf (1.14 to 2.05 kgf) for score break, and 3 to 5 lbf (1.36 to 2.27 kgf) for score tear force.
- Coating integrity performance is shown in Table 3, with the figures being the mA readings from the industry standard enamel rater test. The figures were well within the accepted specification of ⁇ 5mA (mean) / ⁇ 10mA (max) .
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Containers Opened By Tearing Frangible Portions (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU87388/98A AU8738898A (en) | 1997-08-15 | 1998-08-10 | Easy open can ends |
CA002300163A CA2300163A1 (en) | 1997-08-15 | 1998-08-10 | Easy open can ends |
JP2000509545A JP2001514975A (en) | 1997-08-15 | 1998-08-10 | Easy to open can terminal |
EP98938784A EP1003618A1 (en) | 1997-08-15 | 1998-08-10 | Easy open can ends |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9717241.5A GB9717241D0 (en) | 1997-08-15 | 1997-08-15 | Easy open can ends |
GB9717241.5 | 1997-08-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999008819A1 true WO1999008819A1 (en) | 1999-02-25 |
Family
ID=10817482
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1998/002409 WO1999008819A1 (en) | 1997-08-15 | 1998-08-10 | Easy open can ends |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1003618A1 (en) |
JP (1) | JP2001514975A (en) |
AU (1) | AU8738898A (en) |
CA (1) | CA2300163A1 (en) |
GB (1) | GB9717241D0 (en) |
WO (1) | WO1999008819A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3338199A (en) * | 1965-03-17 | 1967-08-29 | American Can Co | Scoring apparatus and method |
US4216736A (en) * | 1979-02-02 | 1980-08-12 | Boise Cascade Corporation | Method and apparatus for forming no-fin scored metal ends |
JPH01139341A (en) * | 1987-11-19 | 1989-05-31 | Kobe Steel Ltd | Edge for scoring drink can lid |
JPH0394938A (en) * | 1989-09-06 | 1991-04-19 | Kobe Steel Ltd | Scoring edge die for drink can cover |
EP0737624A2 (en) * | 1995-04-14 | 1996-10-16 | Pechiney Emballage Alimentaire | Easy open lid having incision located in sloping region |
-
1997
- 1997-08-15 GB GBGB9717241.5A patent/GB9717241D0/en not_active Ceased
-
1998
- 1998-08-10 JP JP2000509545A patent/JP2001514975A/en active Pending
- 1998-08-10 AU AU87388/98A patent/AU8738898A/en not_active Abandoned
- 1998-08-10 CA CA002300163A patent/CA2300163A1/en not_active Abandoned
- 1998-08-10 EP EP98938784A patent/EP1003618A1/en not_active Ceased
- 1998-08-10 WO PCT/GB1998/002409 patent/WO1999008819A1/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3338199A (en) * | 1965-03-17 | 1967-08-29 | American Can Co | Scoring apparatus and method |
US4216736A (en) * | 1979-02-02 | 1980-08-12 | Boise Cascade Corporation | Method and apparatus for forming no-fin scored metal ends |
JPH01139341A (en) * | 1987-11-19 | 1989-05-31 | Kobe Steel Ltd | Edge for scoring drink can lid |
JPH0394938A (en) * | 1989-09-06 | 1991-04-19 | Kobe Steel Ltd | Scoring edge die for drink can cover |
EP0737624A2 (en) * | 1995-04-14 | 1996-10-16 | Pechiney Emballage Alimentaire | Easy open lid having incision located in sloping region |
Non-Patent Citations (2)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 013, no. 392 (M - 865) 30 August 1989 (1989-08-30) * |
PATENT ABSTRACTS OF JAPAN vol. 015, no. 276 (M - 1135) 12 July 1991 (1991-07-12) * |
Also Published As
Publication number | Publication date |
---|---|
EP1003618A1 (en) | 2000-05-31 |
AU8738898A (en) | 1999-03-08 |
JP2001514975A (en) | 2001-09-18 |
CA2300163A1 (en) | 1999-02-25 |
GB9717241D0 (en) | 1997-10-22 |
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