US3397809A - Composite can with easy opening scored can opener end - Google Patents

Description

g- 20, 1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END 3 Sheets-Sheet 1 Filed Aug. 26, 1966 K C O R mm E is M Ma w, H. D 4 M m F a H a FIG,5.

w I W Ilillll ATTORNEY 0, 1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END Filed Aug. 26, 1966 3 Sheets-Sheet 2 INVENTOR DONALD H. ELLERBROCK 62M MW ATTORNEY 0, 1968 D. H. ELLERBROCK 3,397,809

COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END 3 Sheets-Sheet 3 Filed Aug. 26, 1966 I r. "'I

FIG.9.

INVENTOR DONALD H. ELLERBROCK ATTORNEY United States Patent 3,397,809 COMPOSITE CAN WITH EASY OPENING SCORED CAN OPENER END Donald H. Ellerbrock, 1605 Gallant Fox Drive, Florissant, Mo. 63033 Filed Aug. 26, 1966, Ser. No. 575,431 5 Claims. (Cl. 220-48) ABSTRACT OF THE DISCLOSURE This disclosure relates to a metal end particularly designed for use with a composite can to facilitate opening of the can with any of the various conventional can openers presently on the market and also relates to a composite can embodying such an end. The specific disclosure relates to the positioning of a circumferential score line which will materially decrease the resistance to travel of the cutter element of a can opener of the type having a toothed driving Wheel to prevent slippage of the driving wheel during the operation of the can opener,

Ever since the fibre-bodied composite can has been adopted as a low-cost container for certain products such as frozen juice concentrates and other products where the container is normally opened with a conventional can opener, it has been a constant problem for the fibre can industry to develop a can which would permit easy opening with the various types of can openers presently in use. The paperboard material usually used in fibre bodied composite cans is softer, more compressible and thicker than the sheet metal material used in metal bodied cans. These different properties combine with the metal end conventionally used on a fibre bodied can to produce a crimp or seam which is somewhat wider and more compressible than the seam of a metal bodied can. Conventional can openers were originally designed for use with metal bodied cans which inherently have a narrower stronger bead and also a hard metal wall to produce a positive supporting surface which prevents penetration into the body wall by the toothed driving wheel of the can opener and maintains said driving wheel in properly oriented driving relationship with the underside of the can bead, thus preventing undercutting and slippage of the driving wheel with respect to said bead. With the softer fibre body of composite cans the driving wheel engages both the bead and adjacent outer body wall, and on certain can openers tends to penetrate into the body wall causing the driving wheel to undercut the bottom edge of the bead.

In the United States a great number of inexpensive can openers are sold each year. These cause most of the opening problems. Many of these can openers are not sufliciently well made to work properly, even when new, and they do not stand up under the heavy usage given by the modern day housewife in this country. Even if these can openers dont work properly on metal bodied cans the housewife continues to use them; and when used on fibre bodied cans which provide less support than the metal bodied cans, slippage problems occur sufiiciently often to be objectionable. Composite can opening problems have also occurred to a minor degree with certain types of more expensive can openers due to the specific construction and arrangement of the driving and cutting parts of such openers so that the opening of a composite can with the can openers presently in use has been a problem for fibre can manufacturers. The approach taken in United States Patent No. 3,201,259, assigned to the assignee of the present invention, materially improved the situation by providing additional support for the can opener, but did not entirely solve the problem.

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Employees of the assignee have continued to work on this problem and have now provided a metal end particularly adapted for composite cans which materially reduces the resistance of the cutter element to travel around the metal end. It will be apparent that the drivmg force produced by the driving wheel against the can body and the underside of the bead must always be greater than the resistance of the can opener to travel around the can during the cutting operation. Thus, if this resistance can be reduced, less driving force will be required and the possibility of the toothed driving wheel slipping on the body and underside of the bead and thus losing its drive will be substantially reduced.

A number of factors influence the resistance to travel of the can opener around the top of the can. One of these factors is the resistance to cutting or breaking through of the metal itself. Another is the frictional resistance exerted by surfaces of the head on the elements of the can opener respectively engaged therewith. This materially increases the drag and resistance to movement of the can opener around the can which in turn causes slippage of the driving wheel, since the total resistance to travel becomes greater than the driving force produced by the driving wheel of the can opener. If the total resistance to travel (the resistance to cutting or breaking through the metal plus the drag resistance exerted by the can opener elements riding on the engaged surfaces of the bead) is less than the driving force produced by the driving wheel the can will be easily opened by the can opener.

There is a substantial difference in the average diameter of the cutter paths of the various can openers. This can be readily determined by measuring the diameter of the cut out discs produced by the various different can openers after opening an unscored metal end. This can be accomplished by taking a number of circumferentially spaced readings across the diameter of said cut out disc and averaging these readings to determine a definite average diameter thereof. The positioning of the preweakening circumferential score line substantially ad- -jacent the circumferential path of the cutter element of the can opener materially improves the opening characteristics of the metal end closure of the fibre bodied composite can. However, because of these variations in the diameters of the circumferential paths of the cutter elements of the various can openers it is impossible to provide a single score diameter which would substantially coincide with the cutter path of all can openers. Through extensive experimentation with various score diameters I have discovered that the best and most reliable opening characteristics with respect to all different types of can openers are obtained when the diameter of the score line is at least as great as or greater than the average diameter of the cut out disc produced by the particular can opener construction which cuts the largest size disc. In other words, the tests which have been run definitely indicate that positioning the score line outboard of the path of the can opener cutter is necessary to reduce the force required for the cutter element to break through and cut out the central closure disc of the metal end.

For purposes of this application outboard means radially outwardly away from the center of the metal end or outwardly toward the bead or chime of the can seam and inboard means radially inwardly toward the center of the metal end.

It is therefore an object to provide a composite can structure having a laminated hollow body with at least one layer of fibrous paperboard material and end closures on the ends of said body, at least one of said end closures being an easy opening metal end provided with a circumferential score line lying substantially adjacent the cir- 3 cumferentially path of the cutter element of a conventional can opener.

It is another object of the present invention to provide an easy opening scored can opener end for a composite can of the type described, which end is specifically pre-weakened by a circumferential score line lying substantially adjacent the circumferential path of the cutter element of a conventional can opener of the type having a toothed rotary, bead-engaging driving wheel and a cutter element for circumferentially cutting out the metal closure panel of said easy opening end, said circumferential score line reducing the force required to break and cut through said metal end and thereby reduce the driving force required to drive said cutter element around said metal end to cut out the closure panel of said end and thereby facilitate opening the can.

It is a further object to provide a metal end having a circumferential score line the diameter of which is at least as large as or larger than the average diameter of the circumferential path of the cutter element of a conventional can opener of the type described.

These and other objects and advantages will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views, and in which:'

FIG. 1 is a front elevational view of a composite container,

FIG. 2 is an enlarged fragmentary vertical sectional view showing a typical composite can wall construction,

FIG. 3 is an enlarged fragmentary vertical sectional view showing the scored end,

FIG. 4 shows a can opener as it is initially applied to a can immediately before the cutter element is projected downwardly to initially puncture the metal end of the can,

FIG. 5 is a view similar to FIG. 4 showing the cutter element in operative cutting position after the same has been forcibly projected through the can end,

FIG. 6 is a top perspective view showing a can opener in operative position on a typical can,

FIG. 7 is a front perspective view thereof showing the can opener before being clamped into operative position by dotted lines and in operative position by full lines,

FIG. 8 is a sectional view of a can showing from the inside a can opener in operative position thereon, and FIG. 9 is an enlarged fragmentary perspective view of the can end with the can opener shown in cutting position.

One form of a composite can body has been shown for purposes of illustration in this application. The composite can body illustrated herein has a spirally wound laminated body wall 10 with a pair of metal end closures 11 and 12 attached thereto as shown in FIG. 1. This body wall 10 has a spirally wound inner body ply 13 which in the form shown has a skived, overlapped and adhesively connected spiral joint 13a. A suitable outer wrapper or label 14 is adhesively connected to the outer surface of the body ply 13 and a liner 15 is adhesively connected to the inner surface of the body 13. In the form shown the inner liner has a fold-over lap joint 15a which is provided to improve the barrier properties of the liner where a barrier is required. Obviously, more than one ply of body stock material could be used depending upon the required strength of the body wall and the body wall could take the form of a convolute or lap seam construction, both of which have been used by the fiber can industry.

At least one of the metal ends such as the upper end 11 is provided with a pre-weakened circumferential area such as is produced by the score line formed in the outside surface of the end. This score line 20 extends around the outer circumference of the central depressed closure panel of the end 11 and lies in the upper portion of the circumferential radius which connects said central panel with the upstanding wall portion 21 against which the outer bead portion 22 is pressed and supported. The diameter of this score line 20 is at least as large as or larger than the diameter of the cut out disc produced by the can opener which produces the largest sized disc. This positions the score 20 substantially adjacent the circumferential path of the cutting edge 25a of the cutter element 25 of the can opener which normally produces the largest diameter cut out. The metal used in the scored end 11 must be sufficiently hard to prevent tearing away thereof by the toothed driving wheel. The steel conventionally used for metal ends is satisfactory; however, conventional metal end aluminum is too soft.

The most popular type of can opener in use today is the scissor or plier type, such as the can opener shown in FIGS. 4 through 9. This can opener has a pair of levers 26 and 27. A mounting plate 28 fixed to the lever 27 is pivotally connected to the lever 26 as by a rivet 29. The upper portion of the plate 28 has the cutter element 25 formed thereon. A toothed driving wheel 30 is journaled at the end portion of the lever 26 on the opposite end of the pivot 29 from the gripping handle 26a and a turning handle 31 is provided for rotating the driving wheel 30. As best shown in FIG. 5 and by the full line position in FIG. 7 the can opener is applied to the seam. The levers 26 and 27 are squeezed together to project the cutting edge 25a of the cutter element 25 into cutting position and the driving wheel 30 in engagement with the underside 26a of the seam 22 as well as with the portion of the body wall adjacent thereto. It is important that the bead 22 have sufiicient strength to resist collapsing under the pressure produced by the cutter 25 and the driving wheel 30. After initial piercing operation the turning handle 31 is rotated to drive the cutter wheel and cause the cutter element to travel around the inside of the body wall to cut out the panel of the metal end and open the end of the can. The driving force produced by the driving wheel 30 in engagement with the lower edge 22a of the head 22 must be greater than the resistance produced by the cutter edge 25a cutting through the metal end and the frictional resistance to travel of the can opener around the circumference of the can. By providing the weakened score line the resistance to cutting is substantially reduced and thus the driving force produced by the driving wheel 30 is maintained at a higher level than the drag produced by the opening operation.

By maintaining the score line 20 outboard of the outermost cutter element of all the can openers in use, the weakening produced by the score line is effective in reducing the force required to cut through the metal. However, when the score line is inboard of the path of the cutter element, the cutter element will generally cut through the metal outboard of the score line so that a score line inboard of the cutter element is completely ineffective in reducing the resistance to break through essential to solving the can opening problem.

Difierent can diameters and body wall constructions produce different body wall and seam thicknesses. In general, the larger the can diameter the thicker the body wall. Also in general, the thicker the body wall the greater the frictional resistance of the can opener to travel around the can. The thickness of the body wall, the profile of the seam of the metal end an the configuration of the metal end will all produce variations in the diameter of the circumferential path of the cutter element of the can opener. Therefore, the specific design of the score diameter and score depth may vary with each can size and construction.

For example, in the case of the 202 x 314 container presently being made for the citrus concentrate industry, the inside diameter (in inches) of the can body wall is 2.0625 and the diameter of the score line 20 is 2.035. I have found that this score diameter is larger than the average diameter of the circumferential cutter path produced by the various can openers tested. In the case of the 211 X 414 containers also produced for the citrus concentrate industry, the inside diameter (in inches) of the can body wall is 2.573 and the diameter of the score line which is larger than the largest diameter of the circumferential cutter path produced by the various can openers is 2.550.

It is, of course, obvious that there is sufficient residual metal left at the score line to provide sufiicient strength to hold the product confined within the can under usual shipping and handling conditions and this is also critical in connection with the specific can designs for the various products to be packaged.

Since the problem of slippage of the can opener driving wheel 30 has become particularly critical with the increased use of paper bodied composite cans, this is the problem which has been solved by this invention and the scope of this invention will be limited to composite cans having a fibrous layer of material incorporated in the laminated body wall thereof.

It will be seen that I have provided a relatively simple and economical yet highly eflicient solution to the problem which, in spite of the fact that more than one billion composite cans have been sold by the fibre can industry since they were first introduced by applicants assignee in 1960, and in spite of the fact that this problem has existed with all of these cans, the present invention constitutes the first successful solution to the cornposite can, can opening problem. In the past, scored aluminum tear-out ends which require the use of a starter tab and are designed to eliminate the use of a can opener entirely have been tried but have not been generally accepted by the trade since certain problems have occurred with their use, and also since they are considerably more expensive than the standard can opener type end. Applicants invention provides a metal end which not only solves the problem but which can be produced at a cost only slightly greater than the cost of a standard metal end. While the score in the outside surface has been found to be more easily formed in production, this score would serve the same purpose if formed in the inside surface of the metal and.

It will, of course, be understood that various changes may be made in the form, detail, arrangement and proportion of the parts without departing from the scope of my invention which generally stated consists in the matter set forth in the appended claims.

What I claim is:

1. A composite can comprising a hollow laminated body including at least one layer of fibrous paper material and having a pair of end closures respectively closing the ends of said body, one of said closures constituting a metal end seamed onto one end of said body and specifically designed to facilitate opening thereof with a can opener of the type having a cutter element and a toothed driving wheel, said metal end having a circumferential score line formed therein defining a circumferential cutting line lying in the approximate path of the cutter element of the can opener to reduce the resistance to travel of the can opener around the can.

2. The structure set forth in claim 1 and said circum ferential score line lying in the connecting radius between the central closure panel of said metal end and the circumferential upstanding inner wall of the seam.

3. The structure set forth in claim 1 and the diameter of said circumferential score line being at least as great as the diameter of the largest circumferential path produced by the cutter element of any conventional can opener during its travel around the outside of the central closure panel.

4. A metal end for closing at least one end of a composite can of the type having a hollow laminated body including at least one layer of fibrous paper material, said metal end being specifically constructed to facilitate opening thereof with a can opener of the type designed to travel around the head of the metal end and having a cutter element to circumferentially cut out the central closure panel of the end and having a toothed driving wheel for producing the desired circumferential travel around the head, said metal end being characterized by having a circumferential score line positioned to reduce the resistance to breakthrough of the metal end by the cutter element at the score line to permit the driving wheel of the can opener to drive, without slipping, the cutter element around the outer circumference of the central closure panel and said circumferential score line lying in the connecting radius between the central closure panel of the metal end and the circumferential upstanding inner wall of the seam.

5. A metal end for closing at least one end of composite can of the type having a hollow laminated body including at least one layer of fibrous paper material, said metal end being specifically constructed to facilitate opening thereof with a can opener of the type designed to travel around the head of the metal end and having a cutter element to circumferentially cut out the central closure panel of the end and having a toothed driving wheel for producing the desired circumferential travel around the head, said metal end being characterized by having a circumferential score line positioned to reduce the resistance to breakthrough of the metal end by the cutter element at the score line to permit the driving wheel of the can opener to drive, without slipping, the cutter element around the outer circumference of the central closure panel, and the diameter of said circumferential score line being at least as great as the diameter of the largest circumferential path produced by the cutter element of any conventional can opener during its travel around the outside of the central closure panel.

References Cited UNITED STATES PATENTS 1/ 1963 Henchert 22067 7/1965 Saunders 229-55

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