US3485410A

US3485410A - Pressure relief score

Info

Publication number: US3485410A
Application number: US695980A
Authority: US
Inventors: Arnold R Boik
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1968-01-05
Filing date: 1968-01-05
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23
Also published as: AT286164B; DE1757630B2; GB1193556A; BR6905319D0; DE1757630A1; FR1580786A

Description

v,1\.R.Efc il PRESSURE RELIEF scoRE med Jan, s, 196e INvEN'roR ARNOLD Rom United States Patent ABSTRACT OF THE DISCLOSURE This disclosure has to do with an easy opening container wherein a product is packaged therein and sealed `at a pressure other than atmospheric pressure. In order to automatically form a vent opening in the container in advance o-f the rupture of the container during the opening operation performed thereon, the removable panel portion of the container is provided with a weakening line in the form of a score which underlies the pull tab utilized for opening the container and which is protected by the pull tab. The weakening line is disposed in an area of the container which is initially stressed prior to the rupture of the' container panel during the opening of the container and the strength of the panel along the weakening line is c.

such to assure the initial rupture therealong.

This invention relates in general to new and useful improvements in easy opening container, and more particularly to the formation of a vent opening in a container prior to the tearing out of a removable portion thereof.

Although great strides have been made in the formation of easy opening containers of the type wherein a pull tab is provided for facilitating the initial rupture of the container and the tearing out of a removable panel thereof, there still remain problems when the container is packed at a pressure other than atmospheric pressure. If the container is vacuum packed, there is a tendency for implosion. On the other hand, if the container is packed at a pressure higher than atmospheric, when initial rupture occurs, there is a tendency for the air or other enp trapped gases to rapidly rush out through the initially formed opening carrying a portion of the contents of the container therewith. This invention particularly relates to the solution of these problems,

This invention specifically has to do with an easy opening container end unit of the full opening type wherein the problem of implosion and explosion is eliminated by the provision of a specific weakening at a specific point on the container end unit. In a preferred embodiment of the invention, the weakening line is in the form of a score which extends generally transversely of the axis of the associated pull tab and underlies the pull tab so ,as to be protected thereby.

Another feature of the weakening line formed in accordance with this invention is that `the weakening line has reversely curved ends so as to restrict the tearing of the endV unit along the weakening line. p A further feature of the invention is that the ends of the weakening line converge towards one another and are generally directed to the point of engagement of the pul tab with a peripheral weakening line which defines the removable panel portion with the weakening line functioning as a hinge line during the initial opening of the container.

A further feature of the invention is the positioning of v "ice With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and 'the several views illustrated in the accompanying drawing:

IN THE DRAWINGS:

FIGURE 1 is aplan view of a can having an end unit formed in accordance with this invention.

FIGURE 2 is an enlarged fragmentary vertical sectional view taken along the line 2-2 of FIGURE 1 and shows the specific details of the end unit. i

FIGURE 3 is an enlarged fragmentary horizontal sectional view taken along the line' 3--3 of FIGURE 2 and shows specifically the outline of the weakening line and the relationship thereof with respect to a rivet which secures the pull tab to the end unit.

FIGURE 4 is an enlarged fragmentary vertical sectional view similar to FIGURE 2 and shows the initial rupture of the end unit along the weakening line as an opening pressure is being applied to the end unit through the use of the pull tab.

FIGURE 5 is an enlarged fragmentary vertical sectional view similar to FIGURE 2 showing the end unit after the movement of the pull tab to a final rupturing position prior to the tearing out of the removable panel portion.

Referring now to the drawing in detail, it will be seen that there is illustrated a container in the form of a can which is generally referred to by the numeral 10. The can 10 includes a body 11 which is of a conventional construction and which has the upper end thereof closed by means of an end unit, which end unit is generally referred to by the numeral 12 and which is the subject of this invention. The end unit 12 includes an end panel 13 which has the peripheral portion thereof secured to the body 11 by means of a conventional double seam 14.

It will be readily apparent from FIGURE 1 that the end unit 12 is of the full opening type in that the end panel 13 is` provided with a peripheral weakening or score line 15 which is disposed closely adjacent the outer extremity of the end panel 13. In accordance with this invention, the end panel 13 is initially ruptured along a portion of the score line 15 and thereafter the portion of the end panel defined by the score line 15 is torn out along the'score line. This removable panel portion. is defined by the numeral 16.

-In order to facilitate the rupture of the end panel 13 along the score line 15, the removable panel portion 16 is provided with a pull tab 17 of the lever type. The pull tab 17 has a central portion thereof permanently secured to the removable panel portion 16 by means of a rivet 18 which is integrally formed with the removable panel portion 16 in a conventional manner. The pull tab 17 has a nose 20 which is aligned with a part ofthe score line 15 and when the opposite end of the pull tab 17 is elevated relative to the removable panel portion 16, the nose 20 exerts a downwardly directed pressure on the removable panel portion 16 at the score line 15 with the pressure, upon the continued lifting of the pull tab 17, being sufficient to effect the rupture of the end panel 13 along the score line 15. After an initial rupture of the end panel 13 along the score line 15, the pull tab 17 may be utilized in the tearing out of the removable panel portion 16 so as to completely open the can 10.

At this time it is' pointed out that the removable panel portion 16 may have advantageous configurations. For example, the central portion of the removable panelpor tion 16 may be in the form of a recessed panel 21 so as' to stiften the end unit. In a like manner, the removable panel portion 16 may be provided with a second score line 22 which is disposed adjacent the score line 15 and in concentric relation thereto. However, the score line 22 is of a lesser depth than the score line 15, as is clearly shown in FIGURE 2, and functions to absorb shock in the removable panel portion 16 which otherwise might result in the accidental rupture of the end panel 13 along the score line 15.

It will be readily apparent from FIGURES 2 and 4 that when the radially inner end of the pull tab 17 is lifted and the nose 20 is brought into engagement with the removable panel portion 16, there is a tendency to lift the rivet 18 inasmuch as the rivet 18 functions as the fulcrum. Any lifting force applied to the rivet 18 is, in turn, transmitted to the surrounding area of the removable panel portion 16. In accordance with this invention, it is proposed to utilize this highly stressed area of the removable panel portion 16 to form a vent opening in the end unit prior to the initial rupture of the end panel 13 along the score line 15.

Referring now to FIGURE 3, it will be seen that there is formed in the removable panel portion 16 immediately adjacent the rivet 18 a weakening or score line 23. rThe score line 23 has a central portion 24 which is arcuate in outline and which is disposed substantially concentric to the adjacent portion of the rivet 18. At this time it is pointed out that although the rivet 18 is illustrated as being circular in section, it may be of other section and the contour of the central portion of the score line 23 will be modified accordingly. The score line 23 also has reversely turned end portions 25 so that the score line 23 has an overall outline generally resembling a handle bar mustache.

The specific outline of the score line 23 has numerous advantages. In the iirst place, the specific coniiguration and position on the central portion 24 is such so as to facilitate an initial rupture of the end panel 13 therealong. It is to be understood that the strength of the end panel 13 along the central portion of the score line 23 in comparison to the stress applied thereto during the normal opening of the can is less than the strength of the end panel along the score line in comparison to the stress initially applied thereto by the nose of the pull tab 17. Thus, rupture will positively occur along the score line 23 in advance of further rupture along the score line 15. As a result, as is clearly illustrated in FIGURE 4, initial rupture of the end 4panel 13 is in the form of a vent opening 26 which occurs along the score line 23.

It is iirst to be noted that the pull tab 17 overlies the score line 23 and thereby prevents accidental rupture of the end panel 13 along the score line 23. Secondly, when the can is packed at a pressure greater than atmospheric pressure, it will be seen that the pull tab 17 prevents a direct blowing out of gases from within the can 10 while not preventing the desired venting of the can. Further, it will be readily apparent that since the vent opening 26 is in the form of a crack, minute particles, such as ground coffee, etc. will not escape through the vent opening 26 with the outwardly owing gases.

At this time it is pointed out that when the can 10 is packed at a pressure less than atmospheric pressure, the vent opening 26 will function to permit influx of air so as to equalize the pressure within the can 10 with the atmosphere prior to the rupture of the end panel 13 along the score line 15. In this manner the vent opening 26 functions to prevent implosion.

A further feature of the specific score line configuration is that by reversely turning the end portions 25 thereof, uncontrolled tearing or rupture of the end panel 13 is prevented. Furthermore, it is to be noted that the score line 23 facilitates the hinging of a part of the removable panel portion 16 during the initial opening of the can 10, as is shown in FIGURE 5. This hinging action is facilitated by the terminal ends of the end portions 25 being disposed in converging relation and generally directed to the point of engagement of the end panel 13 along the score line 15 by the nose of the pull tab 17.

At this time it is pointed out that although the pull tab 17 is illustrated as having a hinged connection with the rivet 18, it is to be understood that under certain circumstances, the pull tab 17 may be of a rigid construction with the necessary hinging action between the pull tab and the end panel being provided by the score line 23 upon the rupture of the end panel therealong.

Although only a preferred embodiment of the invention. has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the construction of the end unit, without departing from'the spirit and scope of the invention, as defined by the appended claims.

I claim:

.1. A container panel of the type having a removable panel portion defined by a weakening line, a lever type pull tab overlying said removable panel portion, means permanently securing said pull tab to said removable panel portion with an end portion of said pull tab being positioned relative to said weakening line for applying a rupturing effecting force thereon when the opposite end of said pull tab is moved away from said container panel, said removable panel portion having an area thereof which is stressed during the initial movement of said pull tab while applying a force to said container panel along said weakening line, and a second weakening line disposed in said stressed area intermediate said first mentioned weakening line and the connection between said pull tab and said removable panel portion and having reversely turned end portions disposed in converging relation and extending generally towards `said first mentioned weakening line, the relative strength of said removable panel portion along said second weakening line in comparison to the stress applied thereto being less than the strength of said container panel along the lrst mentioned weakening line in comparison to the stress applied thereto whereby said container panel will first rupture along said second weakening line.

2. The container panel of claim 1 wherein said second weakening line extends primarily transversely of said pull tab and underlies and is protected by said pull tab.

3. A container panel of the type having a removable panel portion defined by a weakening line, a lever type pull tab overlying said removable panel portion, means permanently `securing said pull tab to said removable panel portion with an end portion of said pull tab being positioned relative to said weakening line for applying a rupturing effecting force thereon when the opposite end of said pull tab is moved away from said container panel, said removable panel portion having an area thereof which is stressed during the initial movement of said pull tab while applying a force to said container panel along said weakening line, and a second weakening line disposed in said lstressed area intermediate said first mentioned weakening line and the connection between said pull tab and said removable panel portion, the relative strength of said removable panel portion along said second weakening line in comparison to the stress applied thereto being less than the strength of said container panel along the first mentioned weakening line in comparison to the stress applied thereto whereby said container panel will first rupture along said second weakening line, the connection between said removable panel portion and said pull tab including a rivet of arcuate section, and at least a central portion of said second weakening line being in closely spaced concentric relation to an adjacent portion of said rivet.

4. The container of claim 3 wherein said second weakening line terminates in reversely turned end portions.

5. The container of claim 3 wherein said second weakening line terminates in end portions disposed in converging relation and extending generally towards that 3,485,410 5 6 portion of the rst mentioned weakening line aligned with tab is provided with an internal hinge generally aligned said pull tab. with said weakening line.

6. The container panel of claim 1 wherein said pull tab and said reversely turned end portions extend gener- References Clted ally towards that portion of the rst mentioned weaken- 5 UNITED STATES PATENTS i113 line aligned With Said pull tab- 3356270 1/1968 Khoury 220 54 7. The container panel of claim 1 wherein said pull 3,381,848 5/1968 Brown 220 54 tab is provided with an internal hinge generally aligned 3,404,801 10/1968 Silvr 22g-54 with said weakening line.

8. The container panel of claim 3 wherein said pull 10 GEORGE T. HALL, Primary Examiner