System and method for use when forming lift-tab can end assemblies

• US 5,511,920 A
• Filed: 10/14/1993
• Issued: 04/30/1996
• Est. Priority Date: 10/14/1993
• Status: Expired due to Term

• Current Assignee: Jerry Artrip
• Original Assignee: Donald Artrip
• Inventors: Artrip, Donald
• Primary Examiner(s): Lavinder, Jack W.
• Application Number:
  US08/136,803
• Time in Patent Office: 929 Days
• Field of Search: 413/14, 413/16, 413/25, 413/66, 413/12, 29/525.1, 29/525.2, 29/809, 29/818
• US Class Current: 413/25
• CPC Class Codes: B21D 51/383 scoring lines, tear strips or pulling tabs
• CPC Class Codes: Y10T 29/49956 Riveting
• CPC Class Codes: Y10T 29/53522 Means to fasten by deforming

Abstract

A system and process for use when forming lift-tab can end assemblies wherein each can end assembly includes a lift tab having a smooth side, an opposite roughened side and a hole extending between the sides and a can end having a protruding shaft integrally formed in one face thereof utilizes a guide system for inverting a strip of metal stock through about 180° as the strip is conveyed between one workstation at which lift tabs are pre-formed therein and another workstation at which the tabs are punched, so as to sever the tabs from, the strip. The punched tabs are thereafter collected in a stacked relationship and directed to a position adjacent still another workstation at which the tabs are attached, by way of the tab holes and the can end shafts, to the can ends. By inverting the strip of metal stock during the assembly-forming process, the tabs are inverted from a smooth-side-down condition to a smooth-side-up condition for attachment to the can end.

Claims

1. A process for attaching lift tabs to can ends wherein the lift tabs are formed within a strip of flexible metal stock by a tab press so that said lift tabs are formed but remain loosely attached to said strip of metal stock and wherein the lift tabs are formed with a smooth side and an opposite roughened side, the process comprising the steps of:

conveying the flexible metal stock from the tab press so that the lift tabs exit the tab press smooth-side-down and are moved toward a conversion press with an integral punch;

inverting, during the conveying step, the metal stock through about 180 vertical degrees as it is moved toward the conversion press so that upon reaching the conversion press, the lift tabs are oriented smooth-side-up;

punching the lift tabs from the remainder of the strip;

directing the lift tabs into operative registry with the can ends; and

attaching the lift tabs to the can ends; and

wherein the step of directing includes a step of accumulating the punched tabs in a stacked relationship as the lift tabs are punched from the remainder of the strip and permitting the stacked tabs to be gravitationally directed toward a position adjacent the station at which the lift tabs are attached to the can ends.

2. The process as defined in claim 1 wherein the step of inverting effects a rotation of the strip of metal stock in a half-twist through about 180°

.

3. The process as defined in claim 1 wherein the step of inverting effects a rotation of the strip of metal stock in a half-loop through about 180°

.

4. The process as defined in claim 1 wherein the conversion press is one of a multiplicity of conversion presses including integral punch and the step of punching involves the punching of a plurality of tabs from the strip and the subsequent attachment of the lift tabs to can ends at a plurality of stations.

5. A system for forming lift-tab can end assemblies wherein each can end assembly includes a lift tab having a smooth side, an opposite roughened side and a hole extending between the sides and a can end having a protruding shaft integrally formed in one face thereof for receipt by, during an assembly-forming process, the hole in the lift tab, the system comprising:

means for advancing formed can ends in sequence through a first workstation so that as the can ends are advanced therethrough, the shafts formed therein protrude generally upwardly;

means for conveying a strip of metal stock through a second workstation and then through a third workstation wherein the third workstation is elevated above the first workstation and the second workstation is elevated above the third workstation;

first press means disposed at the second workstation for stamping pre-shaped lift-tab workpieces in the strip so that the workpieces are loosely attached to the remainder of the strip and are oriented smooth-side-down as the workpieces move from the second workstation;

the conveying means adapted to direct the strip stock which has been stamped with the pre-shaped workpieces along a path through which the strip stock is inverted so that as each pre-stamped workpiece moves into the third workstation, the workpiece is positioned smooth-side-up;

second press means disposed at the third workstation for punching the pre-shaped workpieces from the remainder of the strip as the strip is advanced through the third workstation;

means for directing the punched workpieces downwardly from the third workstation to a position disposed to one side of the first workstation;

means for moving each punched workpiece from the position disposed to one side of the first workstation to a location at which the workpiece is disposed above a can end positioned in the first workstation, the moving means being coordinated with the conveying means so that as each can end is advanced into position at the first workstation, a corresponding workpiece is moved above the can end so that the hole in the workpiece is positioned in registry with the upwardly-directed shaft formed in the can end; and

third press means disposed adjacent the first workstation for deforming the shaft in a manner which joins the lift tab to the can end.

6. The system as defined in claim 5 wherein the conveying means is adapted to direct the strip stock along a path so that prior to movement of each pre-shaped workpiece into the third workstation, the strip stock is conveyed through a half-twist through about 180°

.

7. The system as defined in claim 5 wherein the conveying means is adapted to direct the strip stock along a path so that prior to movement of each pre-shaped workpiece into the third workstation, the strip stock is conveyed through a half-loop through about 180°

.

8. The system as defined in claim 5 wherein the directing means includes a chute through which the tabs are collected in a stacked relationship and gravitationally directed downwardly from the third workstation to the aforesaid position disposed to one side of the first workstation.