Antifracture coin for panelled can ends

Claim 2

In an easy-opening wall of a container having a rupturable score indented from the outer face of the container wall and defining a relatively large tear panel, the improvement to prevent fatigue failure of the wall at the rupturable score by repeated flexure of the wall caused by repeated impacts of the container content against the container wall during shipment of the container, comprising: the provision of a second nonrupturable score indented from the inner face of the container wall and spaced radially inwardly from the rupturable score to share with the rupturable score the repeated flexure of the container wall and thus lessen the magnitude of the repeated flexure at the rupturable score, the two scores forming flexible hinges to flex in response to outward and inward bulging of the container wall, one hinge opening slightly and the other hinge closing slightly in response to either outward or inward bulging of the container wall.

Claim 3

An improvement as set forth in claim 1 in which the second nonrupturable score is of rounded cross-sectional configuration without sharp corners.

Claim 4

In an easy-opening wall of a container having a rupturable line oF weakness defining a relatively large tear panel, the improvement to prevent fatigue failure of the wall at the rupturable line of weakness by repeated flexure of the wall caused by repeated impacts of the container content against the container wall during shipment of the container, comprising: the provision of a second nonrupturable line of weakness radially inward from the rupturable line of weakness to share with the rupturable line of weakness the repeated flexure of the container wall and thus lessen the magnitude of the repeated flexure at the rupturable line of weakness, the second nonrupturable line of weakness being a score of rounded cross-sectional configuration without sharp corners.

Claim 5

In an easy-opening wall of a container having a rupturable line oF weakness defining a relatively large tear panel, the improvement to prevent fatigue failure of the wall at the rupturable line of weakness by repeated flexure of the wall caused by repeated impacts of the container content against the container wall during shipment of the container, comprising: the provision of a second nonrupturable line of weakness radially inward from the rupturable line of weakness to share with the rupturable line of weakness the repeated flexure of the container wall and thus lessen the magnitude of the repeated flexure at the rupturable line of weakness, the second nonrupturable line of weakness being a score of rounded cross-sectional configuration without sharp corners.

Claim 6

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to assure adequate venting of the container prior to the initial rupture of the container wall at said line of weakness, comprising: the tab having stiffening formations to make the tabs substantially rigid to prevent time-delaying flexure of the tab when the tab is lifted to create the vent opening, said stiffening formations including an offset area that encompasses said two points and forms a continuous stiffening shoulder around the area, said area having a bay extending toward the handle end of the tab encompassing said second point and spacing the second point substantially from the working end of the tab to advance the timing of the venting of the container relative to the timing of the initial severance of the tear panel.

Claim 7

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to assure adequate venting of the container prior to the initial rupture of the container wall at said line of weakness, comprising: the tab having stiffening formations to make the tabs substantially rigid to prevent time-delaying flexure of the tab when the tab is lifted to create the vent opening, said stiffening formations including an offset area that encompasses said two points and forms a continuous stiffening shoulder around the area, said area having a bay extending toward the handle end of the tab encompassing said second point and spacing the second point substantially from the working end of the tab to advance the timing of the venting of the container relative to the timing of the initial severance of the tear panel.

Claim 8

An improvement as set forth in claim 4 in which the handle portion of the tab has stiffening flanges and in which the tab is further formed with longitudinal stiffening ribs spaced from said bay on opposite sides thereof and extending towards the handle end of the tab, the longitudinal zone of said ribs overlapping both the longitudinal zone of said stiffened handle portion and the longitudinal zone of said continuous stiffening shoulder to prevent such flexure of the tab between the handle end and the second point as would significantly delay the timing of the venting of the container relative to the timing of initial manual lift of the handle end of the tab.

Claim 9

An improvement as set forth in claim 5 in which said handle portion forms an opening for the user''s finger and the rim of the opening is flanged to stiffen the handle portion.

Claim 10

An improvement as set forth in claim 6 in which said opening is re-entrant to accommodate the bay and thus permit increased spacing of said second point from the working end of the tab.

Claim 11

An improvement as set forth in claim 6 in which the tab has a stiffening marginal flange extending along both sides of said handle portion and along both longitudinal sides of the tab to the working end of the tab for further stiffening of the length of the tab.

Claim 12

An improvement as set forth in claim 8 in which the working end of the tab is rounded in plan configuration and said stiffening marginal flange is continuous around the working end of the tab.

Claim 13

An improvement as set forth in claim 4 in which said area except for said bay is of generally circular configuration.

Claim 14

An improvement as set forth in claim 4 in which the working end of the tab is relatively blunt to delaY initiation of severance of the tear panel by the tab.

Claim 15

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is at least partially removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to facilitate severance of the tear panel and to assure adequate venting of the container prior to initiation of the severance to the tear panel, comprising: the tab being substantially rigid throughout its length to avoid time-delaying flexure of the tab when the handle end of the tab is lifted, said vent portion of the container wall being within the area of said tear panel and adjacent the region where the tab is attached to the tear panel, the tab being attached to said vent portion by a rivet and the cross dimension of the vent portion being many times the cross dimension of the rivet to shorten the time required for effective venting of the container, at least the leading end and the two sides of said vent portion being defined by a rupturable score, (the leading end of said vent portion being relatively narrow and extending towards the handle end of the tab, said leading end being in general alignment with the longitudinal axis of the tab with said rivet near the tip of the leading end whereby initial severance of the vent portion is facilitated by the rupturable score on opposite sides of the leading end being in approximate alignment with the severance force exerted by the tab,) said vent portion having a relatively wide trailing end adjacent the region where the tab is attached to the tear panel whereby severance of the trailing end substantially weakens the tear panel adjacent said region with consequent lowering of the resistance of the tear panel to bending by the tab to reduce the force required to initiate severance of the tear panel by the tab.

Claim 16

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is at least partially removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to facilitate severance of the tear panel and to assure adequate venting of the container prior to initiation of the severance to the tear panel, comprising: the tab being substantially rigid throughout its length to avoid time-delaying flexure of the tab when the handle end of the tab is lifted, said vent portion of the container wall being within the area of said tear panel and adjacent the region where the tab is attached to the tear panel, the tab being attached to said vent portion by a rivet and the cross dimension of the vent portion being many times the cross dimension of the rivet to shorten the time required for effective venting of the container, at least the leading end and the two sides of said vent portion being defined by a rupturable score, (the leading end of said vent portion being relatively narrow and extending towards the handle end of the tab, said leading end being in general alignment with the longitudinal axis of the tab with said rivet near the tip of the leading end whereby initial severance of the vent portion is facilitated by the rupturable score on opposite sides of the leading end being in approximate alignment with the severance force exerted by the tab,) said vent portion having a relatively wide trailing end adjacent the region where the tab is attached to the tear panel whereby severance of the trailing end substantially weakens the tear panel adjacent said region with consequent lowering of the resistance of the tear panel to bending by the tab to reduce the force required to initiate severance of the tear panel by the tab.

Claim 17

An improvement as set forth in claim 12 in which said handle end of the tab forms an opening for the user''s finger and said opening has a reentrant portion to accommodate said leading end of the vent portion for increased spacing of the rivet from the working end of the tab to advance the timing of initiation of the venting of the container relative to the timing of lifting the handle end of the tab.

Claim 18

An improvement as set forth is claim 12, in which the tab has a depressed area for stiffening of the tab; in which said depressed area is formed with a bay encompassing said rivet; in which the handle portion of the tab has stiffening flanges; and in which the tab is further formed with longitudinal stiffening ribs spaced from said bay on opposite sides thereof and extending towards the handle end of the tab, the longitudinal zone of said ribs overlapping both the longitudinal zone of said stiffened handle portion and the longitudinal zone of said continuous stiffening shoulder to prevent such flexure of the tab between the handle end and the second point as would significantly delay the timing of the venting of the container relative to the timing of initial manual lift of the handle end of the tab.

Claim 19

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is at least partially removabLe to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to facilitate severance of the tear panel and to assure adequate venting off the container prior to initiation of the severance of the tear panel, comprising: the tab being substantially rigid throughout its length to avoid time-delaying flexure of the tab when the handle end of the tab is lifted, the tab being attached to said vent portion by a rivet and the cross dimension of the vent portion being many times the cross dimension of the rivet to shorten the time required for effective venting of the container, at least the leading end and the two sides of said vent portion being defined by a rupturable score, the leading end of said vent portion being relatively narrow and extending towards the handle end of the tab, said leading end being in general alignment with the longitudinal axis of the tab with said rivet near the tip of the leading end whereby initial severance of the vent portion is facilitated by the rupturable score on opposite sides of the leading end being in approximate alignment with the severance force exerted by the tab, said vent portion having a relatively wide trailing end whereby severance of the trailing end substantially weakens the tear panel to bending by the tab to reduce the force required to initiate severance of the tear panel by the tab, the tab having an offset area that encompasses said two points and forms a continuous stiffening shoulder around the area, said area having a bay extending towards the handle end of the tab and encompassing said rivet, said bay overlying the leading end of the vent portion of the container wall.

Claim 20

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is at least partially removabLe to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to facilitate severance of the tear panel and to assure adequate venting off the container prior to initiation of the severance of the tear panel, comprising: the tab being substantially rigid throughout its length to avoid time-delaying flexure of the tab when the handle end of the tab is lifted, the tab being attached to said vent portion by a rivet and the cross dimension of the vent portion being many times the cross dimension of the rivet to shorten the time required for effective venting of the container, at least the leading end and the two sides of said vent portion being defined by a rupturable score, the leading end of said vent portion being relatively narrow and extending towards the handle end of the tab, said leading end being in general alignment with the longitudinal axis of the tab with said rivet near the tip of the leading end whereby initial severance of the vent portion is facilitated by the rupturable score on opposite sides of the leading end being in approximate alignment with the severance force exerted by the tab, said vent portion having a relatively wide trailing end whereby severance of the trailing end substantially weakens the tear panel to bending by the tab to reduce the force required to initiate severance of the tear panel by the tab, the tab having an offset area that encompasses said two points and forms a continuous stiffening shoulder around the area, said area having a bay extending towards the handle end of the tab and encompassing said rivet, said bay overlying the leading end of the vent portion of the container wall.

Claim 21

An improvement as set forth in claim 15 in which said area except for said bay is of generally circular configuration with said trailing end of the vent portion underlying said circular part of said area.

Claim 22

An improvement as set forth in claim 15 in which the width of said trailing end of the vent portion is substantially more than half of the width of the circular portion of said area.

Claim 23

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to assure adequate venting of the container prior to the initial rupture of the container wall at said line of weakness and to reduce the effort required to manipulate the tab, comprising: said vent portion lying close to said first point and being increased in width near the first point for adequate venting and to cause the removal of the vent portion to weaken the wall of the container along a line transversely of the tab near said first point to cause the wall to bend substantially as said line in response to further lifting of the tab after the vent portioN is removed by the tab.

Claim 24

In an easy opening wall of a container having an internal pressure substantially different from atmospheric pressure wherein a rupturable line of weakness defines an at least partially removable tear panel and a vent portion of the container wall is removable to form a vent opening to equalize the pressure across the thickness of the wall and wherein a pull tab of sheet material has a handle end for manual manipulation and has a working end overhanging the tear panel to fulcrum against the tear panel to initiate severance of the tear panel, the tab being attached to the tear panel at a first point intermediate the two ends of the tab and being attached to said vent portion at a second point intermediate the first point and the handle end of the tab point intermediate the first point and the handle end of the tab for removal of the vent portion, the improvement to assure adequate venting of the container prior to the initial rupture of the container wall at said line of weakness and to reduce the effort required to manipulate the tab, comprising: said vent portion lying close to said first point and being increased in width near the first point for adequate venting and to cause the removal of the vent portion to weaken the wall of the container along a line transversely of the tab near said first point to cause the wall to bend substantially as said line in response to further lifting of the tab after the vent portioN is removed by the tab.

Claim 25

An improvement as set forth in claim 18 in which the width of said vent portion is at least half the width of the portion of the tab above the vent portion.

Claim 26

An improvement as set forth in claim 18 in which the width of said vent portion is at least approximately as wide as the portion of the tab above the vent portion.