US3500939A

US3500939A - Method of manufacturing can end

Info

Publication number: US3500939A
Application number: US697173A
Authority: US
Inventors: John S Bozek
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1968-01-11
Filing date: 1968-01-11
Publication date: 1970-03-17
Anticipated expiration: 1987-03-17

Description

March 17 1970 .11. 5. 502m METHOD OF MANUFACTURING CAN END 5 Sheets-Sheet 1 Filed Jan. 11, 1968 JOHN S. BOZEK BY WW,

J. S BUZEK METHOD OF MANUFACTURING CAN END Filed Jan. 11, 1968 3 Sheets-Sheet 2 m m. m m n a. 6 mm I w B ATTORNEYS Man-d1 17, 1970 J. 5. BOZEK METHOD OF MANUFACTURING CAN END 3 Sheets-Sheet 5 Filed Jan. 11, 1968 INVENTOR JOHN S BOZEK @Rlvw/ ATTORNEYS United States Patent 3,500 939 METHOD OF MANUFACTURING CAN END John S. Bozek, Chicago, Ill., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Continuation-impart of application Ser. No. 345,615, Feb. 18, 1964. This application Jan. 11, 1968, Ser.

Int. Cl. B21d 51/00 US. Cl. 113--l21 9 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a method of manufacturing easy opening ends in a manner which avoids end panel and pull tab flipping by forming a score line defining a removable tear-out portion by compressing the material of a metallic blank between a pair of dies. The compression causes an excess portion of the compressed material to be displaced away from the tear-out portion, and this excess portion of the material is absorbed as it is being displaced by drawing the material adjacent the score line out of the normal plane of the blank.

This application is a continuation-in-part of my copending application Ser. No. 345,615, filed Feb. 18, 1964. This invention particularly relates to the manufacture of cans of the easy opening type adapted for the dispensing of beverages, such as beer, soda or the like, wherein an end panel of the can end is provided with a score line which defines a tear-out portion through which the beverage is poured. During the conventional forming of such score lines, there is a gathering of the metal within the area defined by the score line and a general circumferential bulging of the metal outwardly of the score line. The excess metal resulting from the formation of the score line causes two major disadvantages. In the first place,

the excess metal effects a crowding of the remaining metal of the end panel and causes the end panel to be readily flipped from one side to the other of the normal median plane of the end panel with the result that a premature rupture of the end panel along the score line may result. A second disadvantage is that the excess metal which causes the bulging or flipping of the end panel also tends to flip up the free end of the pull tab which is attached to the tear-out portion, whereas the pull tab should remain as flat as possible against the end panel so as not to interfere with the stacking of the can ends or the seaming of the can ends to can bodies.

It is therefore a primary object of this invention to provide a solution of the above-outlined problem, and this solution resides in the drawing of a circumferentially extending rib or groove which is offset from the plane of the end panel during the formation of the score line whereby the rib or groove serves to absorb the excess metal displaced during the forming of the score line and thus greatly reduces the tendency of the end panel and the pull tab to flip in the manner heretofore noted.

A further object of this invention is to provide a novel method of manufacturing easy opening cans in the manner described including the step of securing a pull tab to the tear-out portion in such a manner that the free end of the pull tab overlies the drawn groove whereby in addition to the groove absorbing the excess displaced material, the groove serves to reinforce the entire end panel against flexing to prevent the premature rupture of the end panel along the score line and also facilitates the insertion of ones finger under the free end of the pull tab to effect an upward lifting force thereon.

In further accordance with this invention, several drawn "ice groove or rib arrangements have proved to be feasible with various arrangements having different advantages and disadvantages. By making the groove or rib continuous, there is a greater reinforcement of the end panel against flexing and since the groove extends across the tear-out portion, the groove more effectively absorbs the excess material which results from the forming of the score line defining the tearout portion. On the other hand, the continuous drawn groove or rib has the disadvantage in that it intersects the score line defining the tear-out portion and offers a resistance to the tearing of the end panel along the score line to effect the removal of the tear-out portion. Therefore, in accordance with this method it has also been proved feasible to form only a generally C-shaped drawn groove or rib with the groove or rib terminating closely adjacent opposite sides of the tear-out portion. Such a configured groove or rib construction serves to greatly reinforce the end panel against flexing and at the same time will absorb to a very great extent the excess metal resulting from the formation of the score line. The advantage of the C-shaped formation as compared to the continuous formation is the elimination of the resistance of tearing of the end panel along the score line when the groove or rib traverses the score line.

It has also been found that the reinforcement of the end panel against flexing and the absorption of the excess metal is greatly enhanced when more than one rib or groove is provided. Accordingly, in accordance with this invention, the number of ribs and the configuration thereof may be varied. Furthermore, it has been found that the rib formation is effective when outwardly directed or when inwardly directed. Therefore, while it is more advantageous for the rib to be inwardly directed in that it provides the relief under the free end of the pull tab to facilitate the lifting of the pull tab, in many instances it is feasible to have the rib or ribs outwardly projecting as compared to inwardly projecting.

With the above and other objects in view that will here inafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a top perspective view of a can incorporating the can end which is the subject of this invention, only an upper portion of the body of the can being shown.

FIGURE 2 is a plan view on a reduced scale of the can end and shows the specific outline thereof.

FIGURE 3 is an enlarged fragmentary vertical sectional view taken along the line 33 of FIGURE 2 and shows more specifically the details of the can end along the tearout portion thereof.

FIGURE 4 is an enlarged fragmentary vertical sectional view taken along the line 44 of FIGURE 2 and shows a specific cross section of the generally C-shaped rib or groove formed in the end panel.

FIGURE 5 is an enlarged fragmentary vertical sectional View similar to FIGURE 4 and shows a modified rib or groove configuration.

FIGURE 6 is an enlarged fragmentary vertical sectional view similar to FIGURE 4 and shows the rib projecting upwardly as opposed to projecting downwardly from the plane of the end panel.

FIGURE 7 is a plan view of a can incorporating another form of can end wherein two C-shaped rib formations are provided.

FIGURE 8 is an enlarged fragmentary vertical sectional view taken along the line 8-8 of FIGURE 7 and shows the specific cross section of the can end in the vicinity of the rib formation.

FIGURE 9 is an enlarged fragmentary vertical sectional view similar to FIGURE 8 and shows the ribs PIO- jecting downwardly as opposed to projecting upwardly relative to the plane of the end panel.

FIGURE is a plan view of a can incorporating another form of can end wherein the end panel thereof is provided with a continuous groove or rib formation.

FIGURE 11 is an enlarged fragmentary vertical sectional view taken along the line 11-11 of FIGURE 10 and shows specifically the details of the rib formation and the relationship thereof to the tear-out portion.

FIGURE 12 is an enlarged fragmentary vertical sectional view similar to FIGURE 11 and shows the rib formation as being upwardly projected relative to the plane of the end panel as opposed to being downwardly projected.

FIGURE 13 is a plan view of still another form of can incorporating another modified form of can end wherein the end panel is provided with two circumferentially extending groove or rib formations.

FIGURE 14 is an enlarged fragmentary vertical sectional view taken along the line 1414 of FIGURE 13 and shows more specifically the details of the groove or rib formations.

FIGURE 15 is an enlarged fragmentary vertical sectional view similar to FIGURE 14 and shows the ribs as being upwardly projected as opposed to being downwardly projected relative to the plane of the end panel.

FIGURE 16 is a fragmentary sectional view taken through a pair of die bodies, and illustrates the manner in which the can end of FIGURE 1 is manufactured in v accordance with this invention.

FIGURE 17 is a top plan view of the can end taken generally along line 1717 of FIGURE 16, and illus trates the manner in which excess material which is displaced by the formation of the score line is absorbed by the simultaneous drawing of a C-shaped groove.

FIGURE 18 is a highly enlarged fragmentary sectional view taken generally along line 1818 of FIG- URE 17, and diagrammatically illustrates the manner in which the excess material formed during the formation of the score line is absorbed by the drawn groove.

FIGURE 19 is a fragmentary sectional view taken generally along 1919 of FIGURE 17, and illustrates the final position of the die bodies after the completion of the forming operation.

Before describing the novel method of this invention, reference is first made to various can ends constructed in accordance with this invention, and particularly a can end 12 of FIGURE 1 which is secured by a conventional double seam 13 to a can body 11 of a can 10. The can 10 is particularly adapted for the dispensing of a beverage, such as beer.

In addition to the portion of the can end 12 which forms a part of the double seam 13, the can end 12 includes a. chuck wall 14 and an end panel 15. The end panel 15 is joined to the "chuck wall 14 by an annular groove defining portion 16 which functions as a shock absorber in 'a'manner to be described hereinafter..

The can end 12, heingo'f the easy opening type, is provided with a tear-out portion 17 which is defined by a score line 18. The general outline of the tear-out portion 17 is best shown in FIGURE 2. The tear-out portion 17 is of a conventional configuration and is provided adjacent its inner end and generally at the center of the end panel 15' with an interna11r'ivet19 that is utilized for the purpose of securing a pull tab 20 to'th'e inner end'of the tear-outporti on 17. The illustrated pull '20 is of the rigid'type and the specific details of construction thereof are not a part of this invention.

In the'forming'of the score line 18, there is' a displacement of the metaljof the end panel 15, as will be described more fully inconjunction with FIGURES '16-19. This displacement of the metal results in a crowding of the metal both within the confines of the scoreline 18 and around the score line 18. As a result, thereis' a tendency of the metal to buckle and thus for the end panel thereof; I I

to flipeasily to opposite sides of the median plane thereof. This ease'of flipping of the end panel is undesirable for two reasonsflln the first place, if the end panel is unnecessarily flexed 'back and forth, there is an undue strain placed upon the end panel along the score line 18 with the result that the score line or weakening line 18 may be prematurely ruptured. One of thejprimary disadvantages of a can end that may flip or spring from an outwardly flexed position to an inwardly flexed position or" vice versa after a can has been filled with a carbonated beverage, such-'as'bee'r, and before the can is closed, is that the flipping may cause undue foaming and consequent partial loss of the contents overflowing the top of the open can thereby resulting ina can that is underfilled after it has been closed. Secondly, the undesired upward flipping of the end panel 15, as will occur when the contents of the can 10 is'u'nder pressure, results in an undue flipping of the pull tab 20 away from the surface of the end panel 15.'While it may be desirable from the standpoint of grasping the pull tab 20 for this flipping to occur, it is undesirable from the standpoint of handling and securing in place the end 12. At no time can the pull tab 20 project above the chuck wall14. Furthermore, it is obvious that the pull tab 20 must be sufi'iciently recessed within the can end 12 to clear the customary seaming rolls utilized in the forming of the double'seam 13. In order that the height of the chuck wall 14 and thus the recessing of the end panel 15 may be held to a minimum, it is desirable that the pull tab 20 remain substantially flush against the upper surface of the end panel 15.

In accordance with'this invention, the excess metal resultirig from the forming ofthe score line 18116.8 been absorbed by forming in the end panellS a circumferential r-ib 21. The rib 21 is preferably 'C-shaped in outline, al-

though it is feasible that the rib 21 be divided and that there be only short portions thereof, which short portions are disposed on circumferentially opposite sides of the tearout portion 17. I I 7 It will be readily apparent that by forming a rib or ribs in the end panel 15 on circumferentially opposite sides of the tear-out portion 17, provision has been made for absorption ofthe excess material resulting from the forming of the score" line 18; Thus, in this manner there has been eliminated the undesired bulging of the metal of the end panel 15 and the tendency thereof to flip or flex. Further, it will be readily apparent that the formation of the rib portions on opposite sides of the tear-out portion 17 will result in the localized stiffening of the end panel 15 and prevent the undesired flexing thereof adjacent and along the score line 18.

Although the rib 21 could be in the form of short portions, as is clearly shown in FIGURES 1 and 2, it is continuous and is of C-shaped outline. Thus, the rib 21 serves the dual function of reinforcing the entire end panel 15 against flexing and absorbing the excess material resultingfrom the forming-of the score line 18 so as to therebyfurther reduce the tendency of the material of the end panel 15 for flexing or flipping from the median plane It is also pointed out that the rib 21 could feasibly project either upwardly or downwardly. However, it is preferred that the rib 21 project downwardly from the plane of the end panel 15 so .as to define anzupwardly opening groove 22. By having a groove 22 which opens upwardly and by locatingthe groove. 22. so that it underlies the free end of the pull tab 20, as is clearly shown in FIGURES "1' and 2, sufficient space is provided between the terminal end of the-pull tab 20 and} the surface of the end panel 15 whereby one may place his or her finger beneath the terminal end of-the pull tab 20 and exert the necessary upwardly directed force thereon to effect the tearing of the end panel 15 along the score line 18 whereby removal of the tear-out portion 17 is possible. Thus, it will be readily apparent that the forming of the specifically positioned and shaped rib 21 has three beneficial effects which are highly desirable and which are solutions to existing problems in easy opening can ends.

The rib configuration illustrated in FIGURE 4 has been selected because of the ease of forming the same. However, in lieu of having one generally upright wall 23 and a sloping wall 24, it will be desirable if the rib 21 could have two upright walls. Accordingly, there is illustrated in FIGURE 5 a modification of the can end 12 wherein the end panel 15 thereof is provided with a downwardly offset rib 25 which has two

upstanding walls

26 and 27. The rib 25 is a little more diflicult to form but is of a cross section which will provide greater resistance to distortion as compared to the rib 21.

The can end of FIGURE 6 is formed along the same general lines as the can end of FIGURE 5 with the exception of the fact that in lieu of the downwardly oifset rib shown in FIGURE 5, the can end of FIGURE 6 is provided with an upwardly offset rib 28. The rib 28, like the rib 25, has two upstanding walls 29 and 30. However, since the rib 28 projects upwardly above the plane of the end panel 15, the upstanding walls 29 and 30 project above the plane of the end panel 15.

Reference is now made to FIGURES 7 and 8 wherein there is illustrated another form of can end wherein in lieu of the single C-shaped rib formation shown in FIG- URES 1 through 6, the end panel 15 of the can end is provided with two concentric C-shaped ribs. The outermost of the ribs is referred to by the numeral 31 and the innermost of the ribs is referred to by the numeral 32. It is to be noted that the

ribs

31 and 32 terminate closely adjacent the removable portion 17 of the end panel 15. It is also to be noted that the

ribs

31 and 32 are disposed generally in alignment with the wider part of the tear-out portion 17 where the maximum accumulation of metal occurs. It will be readily apparent that the dual rib formation provides for a greater stiffness than the single rib formation and at the same time provides for a greater absorption of excess metal. It is also pointed out that the concentric rib formations actually result in the formation of a third rib 33 which projects downwardly between the two

upstanding ribs

31 and 32 .When viewed from the top, the rib 33 appears as a groove 34 extending between the

ribs

31 and 32.

Reference is now made to FIGURE 9 which shows the cross section through a slightly modified form of can end from that shown in FIGURES 7 and 8. The can end of FIGURE 9 differs from the can end of FIGURES 7 and 8 in that in lieu of the end panel 15 thereof being provided with two upstanding concentric ribs, the end panel 15 is provided with two concentric depending

ribs

35 and 36. Each of the

ribs

35 and 36 are defined by upstanding walls which appear as upwardly opening groves separated by an upstanding rib 37. It will be readily apparent that the can end construction of FIGURE 9 has all of the advantages of the can end construction of FIGURES 7 and 8. In addition, if the

ribs

35 and 36 are properly spaced, particularly the rib 35, spaced may be provided beneath the extreme end of the associate pull tab 20 to facilitate the lifting thereof.

Reference is now made to FIGURES l and 11 where in there is illustrated another modification of the basic can end. The can end shown in FIGURES l0 and 11 differs from the can end shown in FIGURES 1 through principally in that in lieu of the end panel thereof being provided with a single generally C-shaped rib or groove formation, the rib or groove formation is continuous, as is clearly shown in FIGURE 10. The rib or groove formation, which is referred to by the numeral 38, does not stop on opposite sides of the tear-out porout portion 17, but extends thereacross. It will be readily apparent that such a continuous rib or groove formation has all of the advantages of a similar C-shaped rib or groove formation. In addition, since it extends entirely about the periphery of the end panel 15, it will be seen that the resistance of the end panel against flexing is increased. Furthermore, since the rib or groove formation extends across the tear-out portion, it will be seen that it can better absorb excess metal resulting from the forming of the score line 18.

Although the continuous rib or groove formation has advantages over the C-shaped rib or groove formation as far as reinforcement and the absorption of material is concerned, it will also be apparent that it has a minor deficiency in that it extends generally at right angles to the score line 18. Thus the rib or groove formation 38 resists the tearing of the end panel 15 thereacross along the score line 18 as is required in the normal tearing out of the removable portion 17.

The can end partially shown in FIGURE 12 differs from the can end of FIGURES l0 and 11 only in that it is provided with a continuous rib formation 40 which projects upwardly above the median plane of the end panel 15 as opposed to being depressed therebelow, as is specifically shown in FIGURE 10.

Another form of can end is illustrated in FIGURES 13 and 14 wherein the end panel thereof is reinforced by a continuous groove or rib formation. However, in lieu of the single rib or groove shown in FIGURES 10 and 11, the can end shown in FIGURES 13 and 14 is provided with two concentric rib or

groove formations

41 and 42. The rib or

groove formations

41 and 42 correspond to the rib and

groove formations

35 and 36 shown in FIGURE 9, but in lieu of being C-shaped in outline, they are of a full circle configuration. It is to be noted that the rib or

groove formations

41 and 42 set off what may be considered an upstanding rib 43 therebetween. The continuous rib or

groove formations

41 and 42 have the advantages and disadvantages set forth above with respect to the rib or groove formation 38. As is pointed out with respect to the can end of FIGURES 7 and 8, the two concentric rib or

groove formations

41 and 42 provide for both a greater reinforcement of the end panel 15 against flexure and a greater absorption of the excess metal resulting from the forming of the score line 18.

The can end illustrated in FIGURE 15 is very similar to that shown in FIGURES 13 and 14. However, in lieu of the two depressed rib or

groove formations

41 and 42, the end panel of the can end shown in FIGURE 15 is provided with two upwardly projecting ribs 44 and 45 which are of a circular configuration and disposed in concentric relation. The ribs 44 and 45 are arranged in substantially the same positions as the rib or

groove formations

41 and 42 and the space therebetween is in the form of a circular groove 46.

Reference is now made to FIGURES 16 through 19 of the drawings which fully illustrate the manner in which the can end 12 is manufactured in accordance with this invention. A die 50 is formed of a pair of

die bodies

51, 52 which are relatively movable between opened and closed positions by conventional means (not shown), such as a conventional press.

The die body 51 includes a downwardly projecting scoring rib 53 which has a contour identical to the outline of the score line 18. A rivet-receiving recess 54 is positioned within the area bounded by the rib 53 while outboard of the rib 53 is a C-shaped rib 55 having terminal ends 56, 57. The configuration of the rib 55 corresponds to the configuration of the rib 21 of FIGURES 1 through 3 which forms the C-shaped groove 22 of FIGURES 2, l6 and 17.

The die body 52 also includes a C-shaped groove 58 which is generally a mirror image of the rib 55 and is in axially opposed relationship thereto. The groove 58 includes terminal ends 60, 61 which are similarly in alignment with the respective rib ends 56, 57.

The area of the die body 52 inboard of the C-shaped groove 58 is completely uniplanar except for an upwardly projecting boss 63 which is in axial alignment with the recess 54 of the die body 51.

The easy opening can end 12 is formed by positioning a metallic blank B between the

open die bodies

51, 52, as shown in FIGURE 16. Thereafter, the die body 51 is moved downwardly by conventional means (not shown) during which movement the blank B is formed to the cross-sectional configuration best shown in FIGURE 16. The rivet or boss 19 is formed between the co-operative surfaces of the boss 63 and the recess 54 while the score line 18 and the C-shaped groove 22 are formed by the

respective ribs

53, 57 and the opposed co-operative surfaces of the die body 52. As was heretofore noted, during the formation of the score line 18 the metal of the blank B is displaced or cold flowed in directions both inwardly and outwardly of the score line 18, as diagrammatically indicated by the unnumbered headed arrows in FIGURE 17 and the shaded area A of FIGURE 18. If otherwise unprovided for, as in the conventional manufacturing of easy opening ends, the excess material displaced by the coining of the score line 18 by the rib 53 bulges up along the outboard side of the score line and there is a tendency of the metal to buckle and thus for the end panel to flip easily to opposite sides of the median plane thereof. However, during the formation of the score line 18 between the

die bodies

51, 52, this excess material is absorbed by the simultaneous formation of the groove 22, as indicated by the unnumbered headed arrows to the left of the area A in FIGURE 18 and the area A of FIGURE 19 which graphically represents the full and complete absorption of the displaced material by the groove 22. Thus, in accordance with this invention, the excess metal resulting from the forming of the score line 18 is absorbed by forming in the end panel 15 the circumferential groove 22 (or rib 21), and in this manner there has been eliminated the undesired bulging of the metal of the end panel 15 and the tendency thereof to flip or flex.

The can ends of FIGURES 7 through 15 could, of course, be similarly manufactured in accordance with the method just described, it being only necessary to provide a die corresponding to the die 50 but, of course, provided with opposed die faces formed as mirror images of the opposite surfaces of the various can ends illustrated in FIGURES 7 through 15. Therefore, while the method has been described in conjunction with the die 50 of FIG- URE 16 and the can end 12 of FIGURES 1 and 17, it is to be understood that the method is equally applicable to the remaining cans disclosed therein.

After the can end 12 of FIGURE 17 has been formed in the manner described the pull tab 20 is then merely positioned with its opening (unnumbered) surrounding the boss 19 (FIGURE 16) which is subsequently upset to secure the pull tab 20 to the tear-out portion 17 in a conventional manner. However, in further accordance with this method, the pull tab 20 is so positioned that its free end (unnumbered) is in overlying relationship to the upwardly opening groove 22, as indicated in phantom outline in FIGURE 17 to facilitate the grasping of the pull tab 20 incident to the removal of the tear-out portion 17.

While preferred forms and arrangements of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrange- 8 ment of parts may be made Without departing from the spirit and scope of the invention as defined in the appended claimed subject matter.

I claim:

1. A method of manufacturing an easy opening end in a manner such as to avoid end panel and pull tab flipping comprising the steps of forming a score line de-- fining a removable tear-out portion by compressing the material of a metallic blank between a pair of dies whereby an excess portion of the compressed material created by the compressing operation is displaced away from the tear-out portion, and absorbing the excess portion of the material as it is being displaced by drawing material out of the normal plane of the blank adjacent the score line.

2. The method as defined in claim 1 wherein the score line is a single continuous score line, and the drawn material is a generally C-shaped groove having opposite ends terminating adjacent the tear-out portion and absorbing the excess portion of the material displaced during the scoring operation.

3. The method as defined in claim 1 including the step of securing a pull tab to the tear-out portion with a free end of the pull tab overlying the groove whereby clearance is provided between the pull tab free end and the groove to facilitate the initial lifting of the pull tab.

4. The method as defined in claim 1 wherein the drawing of the material out of the normal plane of the blank is effected across the tear-out portion.

5. The method as defined in claim 1 wherein the drawing of the material out of the normal plane of the blank forms two concentric offset portions of drawn material extending from points adjacent the tear-out portion away from the tear-out portion.

6. The method as defined in claim 5 wherein the ofiset portions are circular and extend across the tear-out portion.

7. The method as defined in claim 5 wherein the offset portions are C-shaped in outline.

8. A method of manufacturing an easy opening end in a manner such as to avoid end panel and pull tab flipping comprising the steps of providing a generally uniplanar metallic blank, forming a score line defining a removable tear-out portion by compressing the material of the blank between a pair of dies whereby an excess portion of the compressed material created by the compressing operation is displaced away from the tear-out portion, and absorbing the excess portion of the material as it is being displaced by drawing material outboard of the tear-out portion out of the normal plane of the blank.

9. The method as defined in claim 8 including the step of securing a pull tab to the tear-out portion with a free end of the pull tab overlying the drawn portion of the blank.

References Cited UNITED STATES PATENTS 3,291,336 12/1966 Fraze 220-54 3,361,291 l/1968 Fraze 220-54 3,400,852 9/1968 Khoury 220-54 RONALD D. GREFE, Primary Examiner