US3273234A

US3273234A - Apparatus for and method of assembling a plastic pull tab with a metal tear strip

Info

Publication number: US3273234A
Application number: US289075A
Authority: US
Inventors: Henchert John
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1961-02-10
Filing date: 1963-06-19
Publication date: 1966-09-20
Anticipated expiration: 1983-09-20

Description

Dept. 20, 1966 HENCHERT 3,273,234

J. APPARATUS FOR AND METHOD OF ASSEMBLING A PLASTIC PULL TAB WITH A METAL TEAR STRIP Original Filed Feb. 10, 1961 INVENTOR Jouu HEHCHEIZT ilnited States Patent Oifi 3,273,234 Patented Sept. 20, 1966 Free 3,273,234 APPARATUS FOR AND METHOD OF ASSEM- BLING A PLASTIC PULL TAB WITH A METAL TEAR STRIP John Henchert, Oak Park, Ill., assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Original application Feb. 10, 1961, Ser. No. 88,473, now Patent No. 3,151,766, dated Oct. 6, 1 964. Divided and this application June 19, 1963, Ser. No. 289,075

4 Claims. (Cl. 29?. 453) This application is a division of my copending application Serial No. 88,473, filed February 10, 1961, now Patpm No. 3,151,766.

This invention relates in general to new and useful improvements in means for opening containers, such as cans, and more particularly relates to a novel apparatus for and method of connecting a pull tab to a tear strip.

' In order to facilitate the opening of containers, such as cans, there has been recently developed the practice of weakening a portion of the container, for example a can end, along lines which define a removable portion of the container, which removable portion has been defined as a tear strip. The tear strip remains an integral part of the container and it is necessary that means be provided to facilitate the tearing of the tear strip from the container. To this end, a pull tab is provided. In accordance with this invention, the pull tab is formed of a resilient deformable plastic having a plug portion which is passed through a flange defined opening in the tear strip. I

The primary ditilculty of passing a plug portion of a plastic pull tab through an opening in a tear strip is that the pressure required to force the plug portion through the tear strip opening is in excess of that required to rupture the tear strip along the weakening lines defining the same. invention to provide a novel apparatus which will permit the ready engagement of plug portions in openings in tear strips with it being assured that no rupturing of the tear strip from the remainder of the container will occur and at the same time the plug portion of the pull tab will have a. sufficiently tight fit within the tear strip opening to assure a scaling of the opening after the connection has been formed.

Another object of this invention is to provide a novel method of assembling a plastic pull tab with a metal tear strip by the forcing of a plug portion of the pull tab through an opening in the tear strip, the method being of a nature wherein it will be rapidly accomplished utilizing a punch and die assembly and wherein the desired conncction may be constantly formed while assuring that no rupture of the tear strip will occur.

A further object of this invention is to provide a novel punch and die assembly for facilitating the insertion of plug portions of plastic pull tabs in openings in relatively thin sheet metal tear strips without undesirably forming the tear strip in a manner to prevent the forming of the desired mechanical interlock between the plug portions and the tear strips which must be of a sealed nature, and without rupturing the tear strips from adjacent portions of containers.

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 ilhutrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of an upper portion of a can having a metal can end which is provided with a tear strip and pull tab in accordance with this invention.

Accordingly, it is the primary object of this FIGURE 2 is a perspective view similar to FIGURE 1 and shows the tear strip partially removed.

FiGURE 3 is an enlarged fragmentary perspective view showing. further the general detailsof the tear strip and pull tab combination.

FIGURE 4 is anenlarged fragmentary vertical sectional view taken along the line 44 of FIGURE 3,

and shows the specific details of the connection between the pull tab and the tear strip.

FIGURE 5 is an enlarged fragmentary transverse vertical sectional view taken along the line 55 of FIGURE 3 and shows further the details of the connection between the pull tab and tear strip, including the fact that the pull tab overlies the metal can end on opposite sides of the tear strip to prevent the accidental rupturing of the can end along the outline of the tear strip by a downward pressure.

FIGURE 6 is a fragmentary exploded view with parts shown in section of the apparatus for inserting the plug portion of the pull tab into the tear strip.

Reference is first made to FIGURES 1, 2 and 3, wherein there is illustrated a conventional type of can which is generally referred to by the numeral 20, and which includes a can body 21 and a can end 22. The can end 22 is preferably formed of a light gauge metal, and it is desirable that the metal be easily rupturable. As a result, normally the can end 22 will. be formed of aluminum, although the usual metals employed in the making of the can ends may be utilized. The can end 22 is secured to the can body 21 by a conventional seam 23. The can 20 is illustrated and described only to set forth one environment of the invention. The present invention is not restricted to cans, but may be used in all types of containers, etc., where it is desired to remove a portion thereof .without utilizing any opening equipment, such as a can opener in the case of a can.

Reference is now made to FIGURE 3 in particular, wherein the can end 22 is illustrated as having a circumferential tear strip 24 which is defined by a pair of

score lines

25, 26 with the score line 25 being disposed outermost and being disposed adjacent the seam 23 so that when the tear strip 24 is removed, substantially the entire can end 22 within the seam 23 will be removed. The

score lines

25, 26 are disposed generally in concentric relation for the most part of their lengths and the score line 26 generally defines an inner panel 27.

The starting end of the tear strip 24 is provided with a pull tab, which is generally referred to by the numeral 28.

The pull tab 28, as is best shown in FIGURES 4 and 5, is formed of a resilient deformable plastic.

The starting end of the tear strip 24 is provided with an opening 29 therethrough defined by an annular flange 30. The flange 30 first extends downwardly and inwardly and is then turned inwardly at a greater angle, as at 31.

The pull tab 28 is provided with a hollow or tubular plug portion 32 adjacent one end thereof. The plug portion extends downwardly from the main part of the pull tab and is provided adjacent its lower end with an annular rib 33 having an upwardly flaring lower portion 34 and a generally square cut upper shoulder 35. The flared lower portion 34 facilitates the insertion of the plug portion 32 through the opening 29 and the engagement of the lower edge of the flange 30 with the shoulder 35 prevents the' accidental Withdrawal of the plug portion 32 through the opening 29. The relationship of the plug portion 32 with respect to the flange is such to assure a sealing of the opening 29 at all times even when a product is packaged in the can 20 under pressure. The lower portion of the annular flange 30 being inwardly directed, when an upward pull is exerted on the pull tab 28, the lower portion of the flange 30 will be cammed inwardly to more firmly grip the plug portion 32 and thus prevent accidental removal of the pull tab 28 from, the tear strip 24.

Referring now to FIGURE 4 in particular, it will be seen that the pull tab 28 has an elongated body portion 36 which is slightly thinner than that portion of the pull tab from which the plug portion 32 depends. The body portion is provided adjacent the end thereof remote from the plug portion 32 with an upper transverse rib 37 and a lower transverse rib 38 to facilitate the grasping of the pull tab 28 and the exerting of a tear strip tearing and removal force thereon. It is to be noted that the rib 38 is of a thickness so as to rest upon the upper surface of the can end 22 in the normal rest at position of the pull tab.

- Reference is now made to FIGURE 6 wherein there is illustrated the apparatus of this invention, the apparatus being particularly adapted for facilitating the assembling of the pull tab 28 with the tear strip 24 and being generally referred to by the numeral 39. When the plug portion 32 of the pull tab 28 is snapped into the tear strip 24, there is a tendency for the flange 30, particularly the lower portion thereof, to straighten out. This is undesirable in that the flange 30 should retain the configuration illustrated in FIGURES 4 and to provide the desired connection with the plug portion 32 of the pull tab 28. It is to this end that the apparatus 39 is provided.

The apparatus 39 includes a base 40 and a relatively movable punch 41. A bore 42 is formed in the base 40 and has an enlarged upper portion 43. The bore 42 is aligned withthe punch 41 and has a coil spring 44 in the lower portion thereof. The coil spring 44 has its upper end bearing against an enlarged bottom portion 45 of an ejector pin 46. A lower portion of a die ring 47 is seated in the bore upper portion 43. The die ring 47 has a bore 48 into which the ejector pin 46 projects. The upper portion of the die ring 47 is provided with a seat 49 which corresponds generally to the exterior surface of the flange 30 and on which the flange 30 is intended to be seated during the securement of a pull tab 28 to a tear strip 24. The die ring 47 is undercut, as at 50, below the seat 49 to receive the rib 33 of the plug portion 32, and it may also be used to limit the upward movement of the ejector pin 46.

When it is desired to assemble the pull tab 28 with the tear strip 24, the can end 22 is seated on the die ring 47 and the pull' tab 28 is seated on the can end in the desired position with the plug portion 32 thereof aligned with the opening 29 defined by the flange 30. The punch 41 is then moved downwardly to exert a pressure on the upper surface of the pull tab 28 in alignment with the plug portion 32. The force exerted by the punch 41 forces the plug portion 32 through the opening 29. However, since the flange 30 is seated on the seat 49, deformation of the flange 30 is prevented. As the plug portion 32 of the pull tab 28 passes through the opening 29 in the tear strip 24, it engages the upper end of the ejector pin 46 and moves the same downwardly against the resistance of the coil spring 44. When the punch 41 again moves upwardly after the seating of the plug portion 32 within the opening 29, the resiliently mounted ejector pin 46 forces the plug portion 32 upwardly with the result that the can end 22 and the pull tab 28 are stripped from the die ring 47 as an assembly.

From the foregoing, it will be seen that novel and advantageous provision has been made for carrying out the desired end. However, attention is again directed to the fact that variations may be made in the examples of the invention disclosed herein without departing from i the spirit and scope of the invention, as defined in the appended claims.

I claim:

1. An apparatus for assembling a pull tab having a resil icnt plug portion and a tear strip having a flanged opening therethrough, said apparatus comprising a die ring having an upper surface for supporting the tear strip and a recessed flange supporting seat, an opening in said die ring below said seat and a spring loaded ejector in the die ring opening, said die ring opening having an annular release portion beneath said seat to both form a stop for said ejector and provide an expansion area for a lower part of said pull tab plug portion projecting beneath said seat whereby the plug portion will necessarily be allowed to expand after it passes through and below the seat, and i a punch aligned with said die ring and being movable towards and away from said die ring.

'2. A method of assembling a pull tab having a resilient plug portion and a tear strip having a flange opening for receiving the plug portion, said method comprising the steps of supporting the tear strip including the sup porting of the flange defining the flanged opening, snapfitting the lower part of the plug portion through the flanged opening while continuing to support the flange, resiliently engaging the plug portion as it passes through the flange and then utilizing the resilient engagement with 'the plug portion to remove the assembled pull tab and tear strip from the support therefor.

3. An apparatus for assembling a pull tab having a resilient plug portion and a tear strip having a flanged opening therethrough, said apparatus comprising a base having a bore therein, a counterbore aligned with said bore and presenting an outwardly facing shoulder, a die ring seated in said counterbore and resting on said shoulder, said die ring having an outer surface for supporting the tear strip and a recessed flange supporting seat, an opening through said die ring in communication with said bore said die ring opening having an annular release portion beneath said seat to both form a stop for said ejector and provide an expansion area for a lower part of said pull tab plug portion projecting beneath said seat whereby the plug portion will necessarily be allowed to expand after it passes through and below the seat, an ejector slidably mounted in said opening, a resilient member seated in said bore and resisting inward movement of said ejector, and a punch aligned with said die ring and being movable towards and away from said die ring.

4. An apparatus for assembling a pull tab having a resilient plug portion and a tear strip having a flanged opening therethrough, said apparatus comprising a die ring having an upper surface for supporting the tear strip and a recessed flange supporting seat, an opening in said die ring below said seat and a resilient ejector unit in the die ring opening, said die ring opening having an annular release portion beneath said seat to both form a stop for said ejector and provide an expansion area for a lower part of said pull tab plug portion projecting beneath said seat whereby the plug portion will necessarily be allowed to expand after it passes through and below the seat, and a punch aligned with said die ring and being movable towards and away from said die ring.

References Cited by the Examiner UNITED STATES PATENTS 2,713,713 7/1955 Tuhbs 29235 X 2,799,971 7/1957 Brudney 29525 X 2,947,071 8/1960 Marchant 29-453 X CHARLIE T. MOON, Primary Examiner.

Claims

1. AN APPARATUS FOR ASSEMBLING A PULL TAB HAVING A RESILIENT PLUG PORTION AND A TEAR STRIP HAVING A FLANGED OPENING THERETHROUGH, SAID APPARATUS COMPRISING A DIE RING HAVING AN UPPER SURFACE FOR SUPPORTING THE TEAR STRIP AND A RECESSED FLANGE SUPPORTING SEAT, AN OPENING IN SAID DIE RING BELOW SAID SEAT AND A SPRING LOADED EJECTOR IN THE DIE RING OPENING, SAID DIE RING OPENING HAVING AN ANNULAR RELEASE PORTION BENEATH SAID SEAT TO BOTH FORM A STOP FOR SAID EJECTOR AND PROVIDE AN EXPANSION AREA FOR A LOWER PART OF SAID PULL TAB PLUG PORTION PROJECTING BENEATH SAID SEAT WHEREBY THE PLUG PORTION WILL NECESSARILY BE ALLOWED TO EXPAND AFTER IT PASSES THROUGH AND BELOW THE SEAT, AND A PUNCH ALIGNED WITH SAID DIE RING AND BEING MOVABLE TOWARDS AND AWAY FROM SAID DIE RING.

2. A METHOD OF ASSEMBLING A PULL TAB HAVING A RESILIENT PLUG PORTION AND A TEAR STRIP HAVING A FLANGE OPENING FOR RECEIVING THE PLUG PORTION, SAID METHOD COMPRISING THE STEPS OF SUPPORTING THE TEAR STRIP INCLUDING THE SUPPORTING OF THE FLANGE DEFINING THE FLANGED OPENINGS, SNAPFITTING THE LOWER PART OF THE PLUG PORTION THROUGH THE FLANGED OPENING WHILE CONTINUING TO SUPPORT THE FLANGE, RESILIENTLY ENGAGING THE PLUG PORTION AS IT PASSES THROUGH THE FLANGE AND THEN UTILIZING THE RESILIENT ENGAGEMENT WITH THE PLUG PORTION TO REMOVE THE ASSEMBLED PULL TAB AND TEAR STRIP FROM THE SUPPORT THEREFOR.