US3627167A

US3627167A - Pull means for tear strip

Info

Publication number: US3627167A
Application number: US858454A
Authority: US
Inventors: Richard D Zenger; Audie L Lambert
Original assignee: National Can Corp
Current assignee: Rexam Beverage Can Co
Priority date: 1969-09-16
Filing date: 1969-09-16
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14

Abstract

The present invention relates to pull means for an easy opening container that includes an end panel provided with a weakened score line defining a tear strip. The pull means acts in the manner of a second class lever and fulcrum action on the tear strip to initiate tearing the tear strip. The pull means includes an end portion having an opening which receives a connecting member interconnecting the pull means with the tear strip and further includes a pair of spaced parallel ribs which are transversely spaced from a plane defined between the axis of the opening and the point at which an opening force is applied to the pull means. The spaced parallel ribs dissipate the forces from generally straight line paths from the edge of the end portion which defines the fulcrum, to a major area of the end portion so as to prevent a weakening of the end portion along the straight line paths which may cause elongation of the opening in the pull means.

Description

nited States Patent [72] Inventors Richard D. Zenger Downers Grove;

Audie 1L. Lambert, Rosemont, botlh 0t llll. 21 Appl'. No. 858,454 [22] Filed Sept. 16, 1969 [45] Patented lDec. M, 1971 [731' Assignee National Can Corporation Chicago, Ill.

[54) lPUlLlL MEANS FOR YEAR STRIP ll ttulms, 5 ihmwlnm Fins.

i 1 220/54 [5 l] B65d17/24 [50] 220/54, 27. 53, 48

[56] References Cited UNITED STATES PATENTS 3,381,848 5/1968 Brown 220/54 3,401,822 9/1968 Fraze 220/54 3,439,833 4/l969. Fraze 3,445,029 5/1969 Zenger Primary Examiner-George T. Hall Attorney-Robert J. Doherty ABSTRACT: The present invention relates to pull means for an easy opening container that includes an end panel provided with a weakened score line defining a tear strip. The pull means acts in the manner of a second class lever and fulcrum action on the tear strip to initiate tearing the tear strip The pull means includes an end portion having an opening which receives a connecting member interconnecting the pull means with the tear strip and further includes a pair of spaced parallel ribs which are transversely spaced from a plane defined between the axis of the opening and the point at which an opening force is applied to the pull means. The spaced parallel ribs dissipate the forces from generally straight line paths from the edge of the end portion which defines the fulcrum, to a major area of the end portion so as to prevent a weakening of the end portion along the straight line paths which may cause elongation of the opening in the pull means.

Patented Dec. 14, 1971 3 27A VEN 70!?5 Mair! D1 Zelzger' 1122, Mgbm? BACKGROUND OF THE INVENTION The present invention relates generally to containers and more particularly to an improved pull means'for a tear-out strip forming part of an easy open end of the container.

Containers having so called easy open ends have become well known in the past several years and now enjoy a considerable measure of consumer acceptability. The easy open end container normally includes an end panel which has at least one weakened line defining a tear strip which is adapted to be removed to gain access to the container. The tear strip is generally removed from the end panel by pull means in the form of a pull ring or tab which is affixed to a portion of the tear strip by means of a rivet. The rivet may be an integral structure forming part of the tear strip or alternatively may be a separate member with the rivet being received through an opening defined in an extension or end portion of the pull means. The end portion of the pull means has an edge defining a fulcrum for the pull means including the end portion and a handle portion connected thereto.

In such devices, when the tearing of the strip is initiated by a pivotal movement of the pull or tab means, considerable difficulty has been encountered in having the pull means separate from the tear strip with the undesirable result of having the tear strip retained on the end panel. The separation of the tear strip has been determined to be caused by elongation of the opening in the pull means or in some cases, fracture of the end portion of the pull means. While one solution to this problem would be to increase the thickness of the material forming the pull means, such a solution is not commercially feasible because of the increased material cost for the pull means.

BRIEF SUMMARY OF THE INVENTION This invention relates to a container having an easy open end including a tear strip connected to a pull means. The pull means includes a handle portion and an end portion with an opening in the end portion receiving connecting means for interconnecting the tear strip and the pull means.

Applicants have determined that the primary cause for the weakening and subsequent fracturing of the end portion along a line between the opening and the fulcrum edge results from a concentration of forces at a small area located adjacent the opening and remote from the fulcrum during the initial pivotal movement of the pull means. This concentration of forces develops from lines of force propagating from the fulcrum points for the pivotal movement toward the opening and it has been determined that the propagation occurs along substantially straight line paths from the fulcrum towards the handle of the tab. Thus, a very small area of the end portion must be capable of absorbing all of the forces which are concentrated as a result of the initial pivotal movement of the pull means.

The present invention contemplates distributing this concentration of forces away from the substantially straight line paths of propagation to a major portion of the end portion of the pull means.

According to the illustrative embodiment of the present in vention, the force distributing means on the end portion is in the form of a pair of elongated ribs which extend substantially parallel to each other and are transversely spaced from a plane defined between the axis of the opening and the point of application of the opening force which tends to pivot the pull means about the axis defined by the fulcrum. The ribs or members extend substantially the entire length between the edge defining the fulcrum and the edge of the handle portion of the pull means. Thus, the force distributing ribs intersect the straight line path of propagation of the forces and result in a distribution of these forces over the major area of the end portion. The redistribution of the forces over the major area of the end portion of the pull means prevents a weakening of the end portion along a line or lines between the opening and the fulcrum edge so as to preclude elongation of the opening a sufficient amount to allow the connecting means to slip out of the opening.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. I of the drawings discloses a fragmentary top perspective view of a container having an easy open end with the present invention incorporated therein;

FIG. 2 is a plan view of the easy open end of the container shown in FIG. 1;

FIG. 3 is an enlarged fragmentary plan view of the tear strip and the pull means;

FIG. 4 is an enlarged sectional view taken generally along lines 44l; and

FIG. 5 is an enlarged sectional view taken generally along lines 5 of FIG. I.

DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail, one specific embodiment with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

FIG. I of the drawings illustrates a container or can 10 having a body I2 which has the lower end thereof (not shown) closed in the normal manner by either an integral end or an end separately secured thereto. The upper end of the container body I2 is closed by means of an easy open end, generally indicated by the reference numeral I4, which is secured to the container body 12 by means of a conventional double seam 16.

The easy open end I4, which is a readily workable material such as aluminum, includes a continuous score line 18 which defines a tear-out section or removable tear strip 20 having a tear initiating or connecting end 22. The tear initiating end or portion 22 is connected to pull means 214 through connecting means which is illustrated as an integral rivet 26. The integral rivet 26 extends through an opening 28 located in a well 29 defined in an end portion 30 forming part of the pull means 24 and the rivet 26 is flattened to overlie the upper surface of the pull means. The well 29 further includes a handle portion 32, which is illustratively shown as a ring having the end portion 30 integral therewith and extending from one edge thereof. As clearly shown in FIG. 5, the ring 32 is formed by doubling over the material. The end portion has an edge 34 which has segments 35 on opposite sides folded under the main body of the end portion. The free ends 36 of the folded portions 35 define fulcrum points during removal of the tear strip.

In removing the tear strip 20 from the remainder of the end panel, the handle portion 32 of the pull means is pivoted about fulcrum points 36 on the end portion 30.

During such pivotal movement of the pull means 24, considerable problem has been encountered in having the opening 2% elongate a sufficient amount to allow the rivet to pass through the opening and thereby allow the pull means to be removed from the tear strip 20 prior to complete removal of the tear strip from the end panel of the container. Further more, in some cases, it has been found that the end portion will be fractured along a line between the edge of the opening 2% and the edge 34 of the end portion 30..

Applicants have determined that the elongation of the opening 2% and/or the fracture of the end portion is caused by a concentration of forces along a portion of the opening which is remote from the fulcrum or edge 34. This concentration of forces, identified by the reference f, develops from the forces that tend to propagate along generally straight line paths from the outer edge 34 of the end portion 30. Inspections have shown that the lines of propagation of forces are generally straight line paths extending from the points of contact of the end portion of the tab and the end 14. The lines of propagation are located on either side of the opening 28 and extending from the edge along lines identified by reference numerals, a and b. This propagation of forces along narrow substantially straight lines from the edge of the end portion 30 towards the handle 32 will tend to stress the metal of the end portion beyond its elastic limit thereby allowing the opening to assume an oval shape or, in some cases, cause a fracture along either of the lines a or b. In either instance, the configuration of the central opening 28 is sufficiently deformed to allow the enlarged portion of the rivet 26 to pass through the opening thereby resulting in a separation of the pull means from the tear strip prior to complete removal of the tear strip.

' The condition described 77 is further aggravated by the fact that the pivotal force on the pull means is generally applied at the remote end of the pull ring 32, identified by the reference numeral 0, which produces a bending of the end portion at a point between the concentration of forces f, and the fulcrum points 36. These bend lines, have been determined to be located along the lines a and b.

According to the present invention, the end portion 30 incorporates elongated means for distributing the concentration of forces awayfrom either of the force lines a or b and dissipating these forces along an area which is substantially parallel to and spaced from a plane located between the axis of the opening 28 and the point of application of the opening or pivotal force, identified by reference c.The force distributing means is illustrated as a'pair of ribs 40 which are spaced from and located on opposite sides of the opening 28 and extend substantially the entire length between the handle portion 32 and the edge 34. The force distributing means or ribs extend a sufficient distance to intersect the normal lines of propagation, a or b, from the edge 34. Thus, the force distributing means or elongated ribs will tend to dissipate these forces across a major portion of the end portion 30 to eliminate the possibility of developing a weakened line between the concentration of forces f and the edge 34. The elongated ribs 40 further resist bending of the end portion along the plane defined between the fulcrum, and the point of application of ivotal force.

Actual tests have shown that the most desirable disposition of the elongated ribs 40 is to have the ribs extend parallel to each other and spaced from the edge of the opening 28 with the axis of the respective ribs extending substantially parallel to the plane defined between the axis of the opening 28 and the normal point of application of the pivotal force. These tests have also shown that the resistance to bending or fracture along either of the lines a or b during the pivotal movement of the pull means 24 is increased a considerable amount by utilizing the force distributing means as illustrated. However, it would be appreciated that the relationship of the force distributing means or ribs 40 and the end portion may assume angles other than the parallel relationship described. For example, the force distributing means could be disposed substantially parallel to the curled edge portions 35 of the end portion 30. Such an angular relationship of the ribs with respect to the plane between the fulcrums and the point of application of force would still distribute the propagation of forces away from the generally straight line path and dissipate these forces over the major portion of the end portion 30.

The particularly pull means have been found to increase the resistance to bending and/or fracture by as much as 30 percent thereby allowing a container manufacturer to reduce the thickness of the metal utilized for the pull means from the thickness of the metal which was heretofore considered necessary to prevent the bending and/or fracture of the end portion during the initial pivotal movement of the pull means to initiate tearing of the strip 20.

What is claimed is:

1. Pull means for removing a tear strip from an end panel of a container comprising a handle portion for exerting a force on said tear strip; and end portion extending from said handle portion, said end portion terminating in an edge spaced from said handle portion and defining fulcrum points on said end panel for said pull means, said end portion havin an opening receiving a connecting portion of said tear strip or interconnecting said tear strip and pull means; said end portion having lines of forces developed therein when an opening force is applied to said handle portion said lines of forces extending from said fulcrum points toward said opening; and a pair of force distributing ribs on said end portion and extending substantially between said edge and said handle means, said force distributing ribs respectively intersecting said lines between said opening and said edge to disperse said forces across a major portion of said end portion.

2. Pull means as defined in claim 1 in which said force distributing ribs extend substantially parallel to each other and to a plane defined between the axis of said opening and the point of application of the opening force on said handle means.

3. Pull means as defined in claim 2, in which said ribs are formed by deforming said end portion.

4. In combination with a container having an aluminum end panel, said end panel having a weakened line defining a removable tear strip, said tear strip having a tear initiation end; pull means having a handle portion and an end portion extending from said handle portion; said end portion having an edge defining fulcrum points overlying said panel and an opening between said edge and said handle portion; connectingmeans received through said opening and interconnecting said tear initiating end and said end portion; and a pair of parallel elongated ribs disposed on opposite sides of said opening and between the fulcrum points and said opening, said ribs being spaced from said opening and extending substantially the entire length of said end portion, said ribs distributing forces over a major portion of said end portion which are concentrated adjacent said opening and tend to propagate from said edge while initiating tearing of said tear strip from said opening by applying a force to said handle means to prevent weakening of said end portion along a line between said opening and said edge which would tend to allow said opening to elongate.

Claims

1. Pull means for removing a tear strip from an end panel of a container comprising a handle portion for exerting a force on said tear strip; and end portion extending from said handle portion, said end portion terminating in an edge spaced from said handle portion and defining fulcrum points on said end panel for said pull means, said end portion having an opening receiving a connecting portion of said tear strip for interconnecting said tear strip and pull means; said end portion having lines of forces developed therein when an opening force is applied to said handle portion said lines of forces extending from said fulcrum points toward said opening; and a pair of force distributing ribs on said end portion and extending substantially between said edge and said handle means, said force distributing ribs respectively intersecting said lines between said opening and said edge to disperse said forces across a major portion of said end portion.

4. In combination with a container having an aluminum end panel, said end panel having a weakened line defining a removable tear strip, said tear strip having a tear initiation end; pull means having a handle portion and an end portion extending from said handle portion; said end portion having an edge defining fulcrum points overlying said panel and an opening between said edge and said handle portion; connecting means received through said opening and interconnecting said tear initiating end and said end portion; and a pair of parallel elongated ribs disposed on opposite sides of said opening and between the fulcrum points and said opening, said ribs being spaced from said opening and extending substantially the entire length of said end portion, said ribs distributing forces over a major portion of said end portion which are concentrated adjacent said opening and tend to propagate from said edge while initiating tearing of said tear strip from said opening by applying a force to said handle means to prevent weakening of said end portion along a line between said opening and said edge which would tend to allow said opening to elongate.