Combined can and end with means for protecting against severed score

[57] ABSTRACT

An easy opening container wall comprising a container wall of sheet material having a line of weakness therein defining a tear portion at least partially removable from the container wall. Removal of the tear portion provides a relatively sharp edge along the tear portion. A dull surface is provided on the tear portion to shield the relatively sharp edge to protect the consumer from injury.

Claims, 9 Drawing Figures

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PATENTED OCT 161973

3.765.352

SHEET 1 OF G

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EBa.

ⁿA^TEMTEDOCT 161973 3.765*352

SHEET 2 OF 6

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P ATENTED OCT IS 1973

SHEET 3 GF G

3,765.352

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ί7· rniTEDOCT 1G1973 3.765,352

SliLTI 4 OF G

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PATENTEDDCT161973 3.765;352

SHEET 5 OF G '

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PATENTED OCT 161973

3.765,352

SHEET G OF 6

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3,765,352

COMBINED CAN AND END WITH MEANS FOR PROTECTING AGAINST SEVERED SCORE

BACKGROUND OF THE INVENTION

As is well known, when an easy opening container is opened, a tear portion or panel is torn from the container to form an opening. The tearing of the sheet material leaves a relatively sharp edge on the removed panel and also leaves a relatively sharp edge on the rim of the opening. These sharp edges are potential sources of danger to the consumer particularly if the container or removed panel is carelessly handled.

This problem is particularly acute in the so-called full panel pullout in which the removed panel covers a major area of the can end. These full panel pullout ends are often used on a food product such as pudding, some of which may adhere to the inner or nonpublic side of the panel. When this occurs, the consumer may lick the inner surface of the removed panel and by so doing may cut his tongue. This of course is only one example of how one of the sharp edges on the panel can produce injury.

SUMMARY OF THE INVENTION

The present invention solves these problems by providing a shield for one or both of the sharp edges. According to the present invention, the sharp edge on the panel is effectively shielded by a relatively dull surface which is positioned so as to make it difficult or impossible to get cut by the sharp edge of the panel. To do this, the dull surface should be closely adjacent the sharp edge, and preferably the dull surface lies slightly radially outwardly of the sharp edge. To most effectively protect against tongue injuries of the type described above, the dull surface should be on the inner side of the can end. Also, if the dull surface were on the outer side of the panel, it would not be possible to easily initiate severance of the panel by forcing a section thereof inwardly.

The dull surface can advantageously be provided by multiple layers of sheet material. In a preferred construction, the panel includes an inner section and a marginal regional with the marginal region having a cross sectional configuration which includes a first reverse bend section opening radially outwardly and a second reverse bend section joined to the first reverse bend section and opening radially inwardly. The dull surface can advantageously be defined by the second reverse bend section which preferably lies generally along or slightly radially outwardly of the score line which defines the panel. With the panel removed, the dull surface projects slightly radially outwardly of the sharp edge to act as a shield or protective device. In addition, the edge of the panel is effectively dulled by the added thickness afforded by the multiple layers of sheet material. Accordingly, even if the dull surface does not project radially outwardly of the sharp edge of the panel, the added thickness of the panel edge as a result of the reverse bends has a substantial dulling effect.

Another advantage of this construction is that the multiple layers of sheet material around the panel periphery stiffens the panel against bending. This facilitates removal of the panel from the container.

To make contact with the sharp edge surrounding the opening in the container more difficult, the region of the peripheral wall of the container closely adjacent the line of weakness is deformed radially inwardly. This re gion of the peripheral wall is forced inwardly at least to a position in which it is substantially axially aligned with the sharp edge on the container. The proximity of the deformed region of the peripheral wall to the sharp edge on the container makes injury to the consumer much less likely to occur.

The deformed region can advantageously take the form of a circumscribing rib. Insofar as protection of the consumer is concerned, the deformed region may project radially inwardly to a location radially inwardly of the line of weakness. However, if initiation of severance of the panel from the container is to be accomplished by depressing a paddle section of the panel inwardly, then the deformed region must not project radially inwardly so far that it interferes with inward movement of the paddle section. In addition, the deformed region should not project radially inwardly so far that it materially hampers removal of the contents from the container. This feature of the invention is useable individually or in combination with the shield for the sharp edge of the panel.

The present invention also provides a novel and advantageous method of making a double fold in sheet material. This method can be used to particular advantage in constructing a preferred form of the easy opening container wall of this invention.

According to the method of this invention, a piece of sheet material is provided with the sheet material having first and second axially offset radial sections integrally joined by a generally axial wall. The second radial section has an expansion rib formed integrally therewith adjacent the axial wall.

Next axially directed compressive forces are applied to the expansion rib to reduce the axial dimension of the rib and to apply a radial outward force to the adjacent end of the axial wall. The effect of partially collapsing the expansion rib is to incline the axial wall in a known direction so that axial compressive forces applied to the two radial sections will provide a double fold. As this double fold or pair of reverse bends is of the type which can be used in the easy opening container wall of this invention, this method is particularly adapted for use in making the preferred form of the easy opening container wall.

Prior to formation of the rib, the connecting wall which joins the two axially offset radial sections can advantageously be subjected to a coining operation. This coining operation is advantageous for several reasons. First, the coining operation elongates the connecting wall and the additional length is useful in providing the two folds. Secondly, the connecting wall is thinned as a result of the coining operation and portions of the thinned connecting wall are used to form the two folds. Cracking is less likely to occur when the folds are formed from relatively thin sheet material. Finally, the thinning of the sheet material used to make up the folds reduces the peripheral stiffening which is obtained from the folds over what it would be if the sheet material of the folds were of full thickness. Peripheral stiffening of the panel is desirable; however, reducing the thickness of the sheet material making up the folds makes it easier to initiate removal of the panel by forcing a paddle section inwardly.

Another feature of this invention is the confining of the sheet material along the score line when the axially directed compressive forces are applied to the rib. This can advantageously be carried out by compressively

3,765,352 engaging the sheet material adjacent the score line and maintaining such compressive engagement during at least a portion of the axial compression of the expansion rib. Such compressive engagement may result in a slight coining of the sheet material adjacent the score line.

The invention can best be understood by reference to the following description taken in connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an easy opening container constructed in accordance with the teachings of this invention.

FIG. 2 is an enlarged fragmentary sectional view taken generally along line 2—2 of FIG. 1.

FIG. 2a is a fragmentary sectional view of the container with the panel removed.

FIGS. 3-8 show a preferred method for constructing the easy opening container wall shown in FIG. 2. FIG. 3 is a top plan view of a can end blank.

FIG. 4 is an enlarged fragmentary sectional view taken generally along line 4—4 of FIG. 3.

FIG. 5 is a sectional view taken on an axial plane and illustrating the tooling for forming a dimple and for coining the connecting wall.

FIG. 6 is a sectional view taken on an axial plane showing the tooling for converting the dimple into a hollow rivet and for formation of the rib.

FIG. 7 is a sectional view taken on an axial plane and illustrating the tooling for initiating axial collapse of the rib and axial compression of the radial sections.

FIG. 8 is an enlarged fragmentary sectional view taken on an axial plane illustrating the axial compression of the container wall to form two reverse bend sections.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 illustrate an easy opening container 11 in the form of an easy opening can. The container 11 includes a generally cylindrical peripheral wall 13 of sheet material, the upper end of which is closed by an easy opening container or end wall 15 which is attached to the upper end of the peripheral wall by interlocking flanges 17 and 19. The lower end or bottom of the peripheral wall 13 can be closed in any conventional manner such as by an end wall integral therewith or by an end wall which is attached to the lower end of the peripheral wall in a conventional manner.

The peripheral wall 13 may be of conventional construction except for an annular rib 21 which projects radially inwardly closely adjacent and beneath the wall 15.

The easy opening container wall 15 is constructed of ⁵⁵sheet material such as aluminum or an aluminum alloy. The easy opening container wall 15 has a line of weakness in the form of a score line 23 which defines a relatively large panel 25 which can be removed from the container 11. The panel 25 covers a major portion of ⁶the area of the container wall 15 and has an inner or nonpublic surface 26. Although the score line 23 could be of various configurations, in the embodiment illustrated, it is circular and concentric with the circular — easy opening container wall 15. An annular coined region 26α of reduced thickness extends along the score line 23.

A tab 27 is attached to the panel 25 in any suitable manner such as by a hollow rivet 29. Although the tab 27 could be of various constructions, in the embodiment illustrated, it is of the type disclosed in common 5 assignee’s copending application Ser. No. 64,291. The tab 27 is integrally constructed from a single piece of sheet metal and generally includes a tab body or lever 31 and an attaching portion or ear 33 which is connected to the tab body 31 by a connecting wall 35. The 10 rivet 29 projects through the attaching ear 33 to attach the tab 27 to the panel 25. The tab body 31 has a lifting end 37 and a rupturing flange 39 at opposite ends thereof.

The tab body 31 has an outer reinforcing curl 43 15 which extends substantially completely around the tab body except for the rupturing flange 39. Adjacent the connecting wall 35, the curl 43 has legs 45 and 47 connected by a bend portion 49 with the latter being engageable with the connecting wall 35. The bend portion 20 49 is round and acts to support the connecting wall during manipulation of the tab.

An outer or marginal region of the panel 25 has the sheet material thereof bent to form an outwardly opening reverse bend portion 51 and an inwardly opening ²³ reverse bend portion 53. The bend portion 53 has a smooth dull surface 55 which lies slightly radially outwardly of the score line 23. As shown in FIG. 2, the reverse bends 51 and 53 are joined to the score line 23 and to the panel 25, respectively. The reverse bends 51 ³⁰ and 53 are formed by three layers of sheet material, and they are interconnected by a straight leg 57 which forms an intermediate layer of the marginal portion of the panel 25. In the embodiment illustrated, the three layers of sheet material which form the reverse bends ³⁵ 51 and 53 are contiguous. As shown in FIG. 2, the reverse bend 53 lies axially inwardly of the score line 23.

When the lifting end 37 is raised, the sheet material of the tab at or adjacent the connecting wall 35 readily bends to allow the tab body 31 to pivot relative to the 4θ attaching ear 33. This forces the rupturing flange 39 against the sheet material along the score line 23 to rupture the sheet material along the score line and to bend a paddle section 58 of the panel 25 inwardly into the container 11 to form an opening 58α (FIG. 2α). The reverse bend sections 51 and 53 stiffen a peripheral region of the panel 25 so that when the tab is pulled outwardly, the panel is easily torn from the container 11 and does not curl.

The rupture of the sheet material forms a relatively sharp edge 59 on the paddle section 58 as shown in dashed lines in FIG. 2 and a relatively sharp edge 60 on the container (FIG. 2α). The dull surface 55 preferably lies radially outwardly of the sharp edge 59 to form a shield or partial sheath therefor. In addition, the edge of the panel 25 is thick because it is defined by three layers of sheet material, i.e., those forming the reverse bends 51 and 53. These two factors combine to make it extremely difficult to be injured by the sharp edge 59.

Even if the dull surface 55 lies slightly radially outwardly of the score line 23, the panel 25 can be completely removed in a conventional fashion by an outward pulling force on the tab 27. When removed, the inner surface 26 of the panel 25 does not contain the sharp edge 59 with the result that licking of the inner surface will not cause cutting of the tongue.

The rib 21 on the peripheral wall 13 preferably projects radially inwardly so that the dull surface 55 of the

3,765,352 paddle section 58 just clears the rib 21 as the paddle section is bent inwardly of the container 11. As shown in FIG. 2a, the rib 21 projects radially inwardly through a location which is in substantial alignment with the sharp edge 60. Thus, the rib serves as a guard to make cutting contact with the sharp edge 60 much more difficult.

FIGS. 3-8 illustrate a preferred method of constructing the easy opening container wall 15. FIG. 3 shows a can end blank 61. The blank 61 includes a peripheral attaching flange 63, an axial wall 65 and a pair of radial walls or sections 67 and 69 which are axially offset and interconnected by a generally axial or connecting wall 71. In the embodiment illustrated, the section 67 and the wall 71 are annular, and the section 69 is circular. The blank 61 may be formed into this configuration with any suitable tooling.

FIG. 5 shows a first work operation in which a dimple 73 is formed and in which the connecting wall 71 is coined to elongate the same. In FIG. 5, the connecting wall 71 is squeezed between a lower coining die 75 and an upper coining die 77 with the compressive force being sufficient to cause thinning and consequent generally axial elongation of the connecting wall 71. The elongation of the connecting wall 71 facilitates formation of the reverse bends 51 and 53. Specifically, the dies 75 and 77 have coining surfaces 79 and 81, respectively, which coin the sheet material between reference lines A—A and B—B. The lower coining die 75 also has horizontal supporting surfaces 83 and 85 for supporting the radial section 67 and an annular region 87 which extends between the connecting wall 71 and the dimple 73. The tooling provides spaces 88 and 88α to accommodate the elongation of the connecting wall 71.

The dimple 73 is formed by a punch 89 and a cooperating die 91. The punch 89 engages the sheet material of the section 69 and offsets a zone of the same into a die cavity 93. Ultimately the offset sheet material is engaged between the cooperating surfaces of the punch 89 and the die 91 to coin the sloping wall of the dimple. The coined regions are generally those portions of the dimple 73 which are shown in FIG. 5 as being compressively engaged. A dimple making process which involves stretching and coining of the sheet material is disclosed in common assignee’s U.S. Pat. No. 3,638,597. The annular region 87 is not coined during the work operation illustrated in FIG. 5.

In the work operation shown in FIG. 6, the dimple 73 is converted into a hollow rivet 95 and the connecting wall 71 is converted into a shorter connecting wall or axial wall 97 and an annular expansion rib 99 which extends between the wall 97 and the rivet 95. The wall 97 extends substantially axially whereas the connecting wall 71 (FIG. 5) is inclined or sloped relative to the axis of the blank 61. The annular expansion rib 99 is closely adjacent the wall 97.

The dimple 73 is converted into the rivet 95 by a rivet punch 101 and a rivet die 103. An outer annular region of the dimple 73 is collapsed and flattened between working faces 105 and 107 of the punch 101 and the die 103, respectively. The punch 101 has a head 109 which is within the rivet 95 to assist the formation thereof, and the rivet 95 is in a die cavity 111.

The expansion rib 99 is formed by stretching and deformation of the sheet material of the connecting wall 71 by a punch 113 and a die 115. The punch 113 has a head 117 which engages the sheet material and forces the same into a die cavity 119.

The wall 97 is formed from the upper regions of the connecting wall 71. This is accomplished by the punch 113, the die 115 and a tool 121. In addition, the die 115 cooperates with the tool 121 to bend the sheet material at the juncture of the section 67 and the wall 97 so that the wall 97 extends in a substantially axial direction.

In the work operation shown in FIG. 7, the score line 23 is formed and an axial compressive force is applied to the expansion rib 99 by a pair of compression tools 125 and 127. The scoring operation can advantageously be carried out by a scoring die 129 and by a tool 131 which supports the section 67. A spring 130 urges the die 129 and the tool 127 in opposite directions.

The tool 127 and the die 129 are advanced relative to the tools 125 and 131. The tool 127 strikes the upper end of the expansion rib 99 to initiate axial collapse and radial expansion thereof. Radial expansion of the expansion rib 99 moves the lower end of the axial wall 97 radially outwardly with the wall 97 pivoting about a region 132. In addition, as the scoring tool 129 is relatively advanced, it applies an axial compressive force to the radial sections 67 and 69 with the result that the wall 97 becomes more inclined relative to the axis of the blank 61 in the manner shown in FIG. 7. The expansion rib 99 is reduced in height by less than 50 percent, and preferably about 40 percent, in the work operation of FIG. 7.

During the operation shown in FIG. 7, the sheet material adjacent the ultimately formed score line 23 is confined by the tool 131 and the scoring die 129. As the die 129 and the tool 131 relatively advance the sheet material between the die 129 and the tool 131 is compressively engaged to hold the section 67 in position and to form the score line 23. At the end of the stroke the sheet material radially outwardly of the score line 23 is coined by a coining face 132α, and this further tends to hold the section 67 in position during the last bit of radial expansion of the expansion rib in the operation of FIG. 7. Ordinarily the material radially inwardly of the score line 23 will be thinner than the material radially outwardly of the score line 23 as a result of the coining operation of FIG. 5, and consequently, the face 132α will not ordinarily coin the material radially inwardly of the score line.

By confining and compressively engaging the sheet material adjacent and along the score line 23 to prevent movement thereof, stresses of the type which might create tiny cracks or openings in the sheet material along the score line are less likely to occur. In addition, slight coining adjacent the score line 23 is believed beneficial to the characteristics of the sheet material along the score line.

FIG. 8 illustrates the next work operation in which the radial sections 67 and 69 are moved toward each other with consequent collapse of the wall 97 to form reverse bend sections 51 and 53 substantially as shown in FIG. 2. During the work operation of FIG. 8, the blank 61 is retained between workholders 137 and 139, and the punch 141 is received within the rivet 95. A compression tool 143 is moved upwardly as viewed in FIG. 8 to collapse the axial wall 97 to thereby form the reverse bends 51 and 53. Specifically, the reverse bend sections 51 and 53 are formed by squeezing of the sheet material between the workholder 139 and the compres

3,765,352 sion tool 143. In addition, the tool 143 cooperates with a tool 145 to spank or flatten the annular zone of sheet material immediately surrounding the rivet 95.

Some of the material of the connecting wall 71 is used to form the reverse bends 51 and 53. Because the connecting wall 71 has been thinned, the reverse bends 51 and 53 are more easily formed and are less likely to have cracks.

Following the work operation of FIG. 8, the tab 27 (FIGS. 1 and 2) can be attached to the blank 61 by heading of the rivet 95 to thereby convert the latter into the rivet 29 (FIGS. 1 and 2). Thereafter, the resulting easy opening container wall can be attached to the container 11 as shown in FIG. 2.

Although the method shown in FIGS. 3-8 is particularly adapted for making an easy opening container wall of the type shown in FIG. 2, it may be used in other instances where it is desired to form a double fold or double reverse bend sections such as shown in FIG. 8.

Although exemplary embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.