Progressive die manufacturing method and associated tooling assemblies for ergonomic pull tabs

Abstract

A progressive die manufacturing method produces a pull tab for opening container lids with frangible regions. The method creates a tapered pull tab body with a nose portion and an elevated lift portion. The body's tapering angle is optimized for stackability and support. At least one bend elevates the lift portion, creating a vertical distance between top and bottom planes. The entire lift portion is elevated and extends between opposing sides for improved user interaction. Specialized tooling assemblies in a lift or reform station create precise bends at specific locations and maintain tight tolerances. This method produces pull tabs with enhanced accessibility and opening comfort while maintaining compatibility with existing container lid designs, including those with shadow beads, and stacking requirements. The invention balances material flexibility, structural integrity, and manufacturability, representing a significant advancement over prior art in ergonomics and production efficiency.

What is claimed is: 
     
         1 . A progressive die manufacturing method of producing a pull tab for opening a container of a type having a frangible region of a container lid and a rivet adjacent the frangible region, comprising steps:
 providing a carrier sheet of metal suitable for forming into pull tabs;   producing at least one tab blank from the carrier sheet, each tab blank fixed with one or more carrier strips of the carrier sheet at one or more attachment points on the pull tab;   forming each tab blank into a pull tab having:   a body extending along a longitudinal axis from a forward end to a rearward end, the body having:
 a nose portion at the forward end configured to apply downward pressure on the frangible region of the container lid, 
 a lift portion at the rearward end disposed distally from the nose portion and terminating at a distal end of the pull tab, 
 a pair of opposing sides extending from the nose portion to the lift portion, 
 a top surface defining a top plane and a bottom surface defining a bottom plane, the body forming a variable thickness profile along the longitudinal axis, such that: 
 the thickness of the body at the nose portion is greater than the thickness at the lift portion; 
 the thickness increases to a peak thickness between the nose portion and a first bend; and 
 the thickness tapers from the peak thickness to the lift portion; 
 a rivet island aperture in the body between the opposing sides proximate the nose portion, the rivet island aperture defining a rivet island that includes a rivet aperture for attachment with the rivet of the container lid; and 
 a finger hole in the body between the opposing sides between the rearward end and the rivet island aperture; 
   moving the carrier sheet and pull tabs to a forming station;   at the forming station, bending the sides of the pull tab to elevate the lift portion relative to the top plane of the pull tab by forming the first bend in the body between the nose portion and the lift portion.   
     
     
         2 . The progressive die manufacturing method of  claim 1  wherein the step of bending the pull tab at the forming station comprises:
 forming the first bend in the body between the nose portion and the lift portion; 
 forming a second bend in the body between the rearward end and the first bend; 
 wherein the lift portion is disposed between the rearward end and the second bend, and an intermediate portion of the body is defined between the first bend and the second bend, with the first bend and the second bend collectively elevating the lift portion above the top plane of the pull tab. 
 
     
     
         3 . The progressive die manufacturing method of  claim 2  wherein the step of bending the pull tab further comprises:
 positioning the first bend between 19.25 millimeters and 21.5 millimeters, along the longitudinal axis from the forward end, and forming the first bend at an angle of between 10 degrees and 45 degrees with the top plane; and 
 positioning the second bend between 20 millimeters and 23 millimeters along the longitudinal axis from the forward end, and forming the second bend at an angle of between 10 degrees and 45 degrees with a lift portion top plane, wherein the lift portion top plane is substantially parallel to the bottom plane. 
 
     
     
         4 . The progressive die manufacturing method of  claim 3  wherein the step of bending the pull tab further comprises:
 positioning the first bend about 19.75 millimeters from the forward end; 
 positioning the second bend about 22 millimeters from the forward end; and 
 forming the first and second bends at angles of about 19 degrees each. 
 
     
     
         5 . The progressive die manufacturing method of  claim 1  wherein the step of forming each tab blank into a pull tab further comprises:
 forming the body such that the top plane and the bottom plane form an angle of between 2 degrees and 10 degrees from the nose portion to the first bend, resulting in the tapering of the body. 
 
     
     
         6 . The progressive die manufacturing method of  claim 5  wherein the step of forming the body further comprises:
 forming the angle between 4 degrees and 5 degrees. 
 
     
     
         7 . The progressive die manufacturing method of  claim 1  wherein the step of forming each tab blank into a pull tab further comprises:
 forming the thickness at the nose portion to be between 1 millimeter and 2 millimeters. 
 
     
     
         8 . The progressive die manufacturing method of  claim 7  wherein the step of forming the thickness at the nose portion further comprises:
 forming the thickness to be about 1.35 millimeters. 
 
     
     
         9 . The progressive die manufacturing method of  claim 1  wherein the step of forming each tab blank into a pull tab further comprises:
 forming the lift portion to have a width between each opposing side of between 12 millimeters and 16 millimeters. 
 
     
     
         10 . The progressive die manufacturing method of  claim 9  wherein the step of forming the lift portion further comprises:
 forming the width of the lift portion to be about 14 millimeters. 
 
     
     
         11 . The progressive die manufacturing method of  claim 3  wherein the step of bending the pull tab further comprises:
 forming the lift portion to have a vertical distance from the lift portion top plane to a lift portion bottom plane of between 0.5 millimeters and 1 millimeter. 
 
     
     
         12 . The progressive die manufacturing method of  claim 11  wherein the step of forming the lift portion further comprises:
 forming the vertical distance from the lift portion top plane to the lift portion a bottom plane to be between 0.7 millimeters and 0.8 millimeters. 
 
     
     
         13 . The progressive die manufacturing method of  claim 1  wherein the step of bending the pull tab further comprises:
 elevating the lift portion above the top plane of the pull tab and extending the lift portion between each opposing side, thereby providing a continuous elevated surface for user interaction. 
 
     
     
         14 . The progressive die manufacturing method of  claim 1  wherein the step of forming each tab blank into a pull tab further comprises:
 forming the body such that the top plane and the bottom plane form a tapering angle between 0.2 degrees and 5.6 degrees from the first bend to a topmost point of the pull tab at a peak thickness. 
 
     
     
         15 . The progressive die manufacturing method of  claim 2  wherein the step of bending the pull tab further comprises:
 forming a lift angle between the intermediate portion and the lift portion top plane, wherein the lift angle is configured to provide elevation for the lift portion to interact with container lids featuring shadow beads. 
 
     
     
         16 . A forming station tooling assembly for use in a progressive die manufacturing process for producing pull tabs with an elevated lift portion, comprising:
 an upper tooling assembly; and   a lower tooling assembly,   wherein the upper and lower tooling assemblies are configured to introduce a first bend and a second bend in sides of a pull tab blank to elevate a lift portion of the pull tab above a top plane of the pull tab by forming a dual-bend structure in a body between a nose portion and the lift portion of the pull tab, the first bend and the second bend being formed at specified locations along a longitudinal axis of the pull tab each between 19.25 millimeters and 23 millimeters from a forward end of the pull tab.   
     
     
         17 . The forming station tooling assembly of  claim 16  wherein:
 the first bend is positioned between 19.25 millimeters and 21.5 millimeters along the longitudinal axis from the forward end, and forms an angle of between 10 degrees and 45 degrees with the top plane; and 
 the second bend is positioned between 20 millimeters and 23 millimeters along the longitudinal axis from the forward end, and forms an angle of between 10 degrees and 45 degrees with a lift portion top plane, wherein the lift portion top plane is substantially parallel to a bottom plane of the pull tab. 
 
     
     
         18 . The forming station tooling assembly of  claim 17  wherein:
 the first bend is positioned about 19.75 millimeters from the forward end, and the second bend is positioned about 22 millimeters from the forward end; and 
 the angles formed by the first and second bends are each about 19 degrees. 
 
     
     
         19 . The forming station tooling assembly of  claim 16  configured to form the lift portion such that a total height from a bottom plane of the pull tab to a lift portion top plane is between 1 millimeter and 4 millimeters. 
     
     
         20 . The forming station tooling assembly of  claim 19  wherein the total height is about 1.5 millimeters. 
     
     
         21 . A forming station tooling assembly for use in a progressive die manufacturing process for producing pull tabs with an elevated lift portion, comprising:
 an upper tooling assembly; and   a lower tooling assembly,   wherein the upper and lower tooling assemblies are configured to form a variable thickness profile along a body of a pull tab, such that:   a thickness of the body at a nose portion, measured between a top surface defining a top plane and a bottom surface defining a bottom plane, is greater than a thickness at a lift portion;   the thickness of the body increases from the nose portion to an intermediate peak thickness located between the nose portion and a first bend;   the thickness of the body tapers from the intermediate peak thickness to the lift portion, such that the variable thickness profile provides a gradual reduction in material toward the lift portion along a longitudinal axis; and   the upper and lower tooling assemblies are further configured to form upward bends on opposing sides of the pull tab, such that the bends elevate the lift portion above a longest continuous top plane prior to any deformations or bends of the pull tab.   
     
     
         22 . The forming station tooling assembly of  claim 21 , wherein the thickness of the body includes:
 a thickness of approximately 1.35 millimeters at the nose portion;   an intermediate peak thickness of approximately 1.5 millimeters located between the nose portion and the first bend; and   a thickness of approximately 0.75 millimeters at the lift portion.   
     
     
         23 . The forming station tooling assembly of  claim 21 , wherein the tapering profile of the body between the bottom plane and the top plane along the longitudinal axis forms a tapering angle from the first bend to the intermediate peak thickness, the angle ranging between 0.2 degrees and 5.6 degrees. 
     
     
         24 . The forming station tooling assembly of  claim 23 , wherein the tapering angle is approximately 2.1 degrees. 
     
     
         25 . A reform station tooling assembly of  claim 21  wherein deformations in the pull tabe are formed using an upper reform punch and lower reform die.