Forming catch tabs on paperboard food container components for retaining containers and lids in releasable attachment

Abstract

A die set apparatus for forming catch tabs on a flange of a first paperboard container component, such as a lid, while the paperboard is being pressed between a pair of mating dies. A plurality of cavities are formed in and circumferentially spaced around a first die, each cavity opening toward a second die and having a shearing edge. A plurality of radial passages extend through a second die, each passage in registration with one of the cavities. A plurality of catch punches are mounted for radial movement through a radial passage and into its associated cavity. Each catch punch also has a shearing edge aligned to closely slide past the shearing edge of its associated cavity. An actuator drives the catch punches into the cavities to shear a slit in the interposed paperboard and drive an adjacent segment of paperboard into the cavity to preform the catch tabs. As the dies are separated, each catch tab is caught on the edge of the cavity and bent inwardly, tearing the paperboard at opposite ends of the slit so that the tears form opposite sides of the catch tabs.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the manufacture of catch tabs on pressformed, paperboard, food container component parts, such as lids and trays, for retaining food container components in manually releasable attachment.

2. Description of the Related Art

A popular type of package for food and beverages is a two-part package consisting of a lower container and a cover which have mating rims that permit the two to be removably attached together in order to enclose the food. They have mating rims that are typically characterized by a peripheral, annular lip, such as a rolled rim or a generally horizontal flange, on one of the two parts and a peripheral, generally axially extending, annular flange on the other part that has projecting catch tabs that can be passed over and then latched against the lip or flange. Usually, the generally axially extending, peripheral flange extends outwardly of and surrounds the lip or generally horizontal flange and the catch tabs extend radially inwardly from the axially extending flange. However, these relative positions can be reversed.

Food containers of this type come in a variety of configurations having other common features. Usually, one part of the container has sidewalls of substantial height and the other part is relatively flat, with no substantial sidewalls. For example, for beverages, such as soft drinks and coffee, the lower part has sidewalls of a substantial height with an outwardly extended rolled lip around its top rim and receives and supports the food item. The upper part is a relatively flat lid for completing the enclosure and is formed by a panel with a peripheral, axially extending flange with radially inwardly extending catch tabs. For some food products, such as cakes or vegetables, these relative positions are reversed so that the lower part is relatively flat, it receives and supports the food item and is referred to as a tray or dish and the upper part has sidewalls of a substantial height for completing the enclosure of the food item and is sometimes referred to as a cover. For still other food items, both component parts have sidewalls of substantial height. All of these types of container structures can be inverted and their size can be modified and they still are containers having a lower component part and an upper component part.

Furthermore, the lip or flange can be formed on either the upper or the lower component part and the generally axially extending, annular flange, with its catch tabs, can be formed on the other component part. Therefore, terms such as lid, tray, cup, dish etc. can be misleading and confining when used with these containers because those terms imply a top or bottom position even though the structural features are interchangeable.

In view of this variability and the interchangeability of the position, size and orientation of these container structures, and in an attempt to have a consistent terminology without requiring multiple repetitions of substantial equivalents, certain terminology has been adopted. Instead of the terms lid, cup, tray, dish, etc. the term “container component part” is used and containers to which the invention applies ordinarily has two container component parts. The term “axially extending flange” is used to refer to the structure on a first component part of a container that has catch tabs for releasably latching the first component part to the second component part. When the components are joined, the axially extending flange is usually located outwardly of and surrounding the lip or flange of the second component part. The term “lip” is used to refer to the lip or flange of the second component part that is held by the catch tabs. It should be understood, however, that the term “axially extending flange” is not confined to a flange-like structure that is itself necessarily parallel to the axis of the container component part. That flange is usually somewhat oblique to the axis. It is only necessary that the “axially extending flange” lie generally along a resultant that has a directional component that is parallel to the axis so that, when the container component parts are moved along their axes to bring the two component parts into closed engagement, the catch tabs will pass over and then latch to the lip.

Additionally, while some container component parts have substantial sidewall heights and some do not, all can be described as having an “open end” and a “closed end”. The open end is the axial end of a container component part that faces the other component part and the two components are joined at their open ends. For example, a lid has a panel extending across and closing its top and a cup and a tray each have a bottom panel closing its bottom. Both the axially extending flange formed with the catch tabs and the lip that engages the catch tabs are typically formed near the open ends of the container component parts. The axially extending flange can extend from and be integrally formed with a wall of a peripheral groove formed in a closed panel of a lid or plate. The axially extending flange can extend from a sidewall and it can be an integral extension of a sidewall.

Thermoformed drinking cup lids, cake platforms, and other various types of carry-out food packaging made from several types of plastic materials have long been used in the food and beverage industry. Plastic materials are easily molded or formed into desired shapes. Consequently, plastic food container component parts have long been formed with catch tabs or indentations protruding from an axially extending flange on a first container component part to latch the first component part onto a second component part. This is most common for lids for soft drinks and coffee.

Paperboard has also long been used for forming component parts for food containers. One successful manufacturing technique is pressforming or thermoforming of the paperboard. In this technique, paperboard stock, typically corrugated paperboard, is pressed between mating, heated dies and formed into a desired shape. The pressforming of paperboard has been used to form a broad variety of container component parts.

Many consumers and companies would prefer to use paperboard for lids, trays and other container component parts because paperboard has better inherent insulating properties and better graphic printing capabilities, is more environmentally friendly because it more readily and quickly deteriorates when discarded outdoors and is a renewable resource. However, in the past it has not been possible to obtain tight fitting lids or other container component parts in certain applications with the use of paperboard and/or combinations of paperboard and plastic. This has been primarily due to the fact that it has not been possible to form interior or “reversed” catch tabs in the paperboard packaging using the conventional male/female forming dies utilized in the existing pressforming technology.

It is therefore an object and feature of the invention to provide a method and apparatus that can be used to form catch tabs on the axially extending flange of a container component part for latching with the lip of another container component part and to provide a paperboard container component part having such catch tabs.

BRIEF SUMMARY OF THE INVENTION

Catch tabs are formed on an axially extending flange of a first paperboard container component part by shearing a plurality of circumferentially spaced slits through the axially extending flange and radially punching the paperboard adjacent each slit to deform a segment of the paperboard adjacent the slit in a radial direction. Preferably, each catch tab is caught on an edge formed on one of the forming dies, as the dies are separated, so that the catch tab is bent away from the axially extending flange and toward the open end of the container component part. This bending tears the paperboard at opposite ends of the slit so that the tears form opposite sides of the catch tab.

To do this, a plurality of cavities are circumferentially spaced around a first die portion, each cavity opening toward a second die portion and having a shearing edge. A plurality of radial passages extend through the second die portion, each passage in registration with one of said cavities. A plurality of catch punches are each mounted for radial movement through a radial passage and into an associated one of the cavities. Each catch punch includes a shearing edge aligned to closely slide past the shearing edge of its associated cavity. An actuator is drivingly linked to each catch punch for driving the catch punches into the cavities and thereby shearing a slit in the interposed paperboard and driving an adjacent segment of paperboard into the cavity to form the catch tab or an initial preform of the catch tab.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1-3 are half views in axial section of paperboard forming dies incorporating an embodiment of the invention and illustrating its operation.

FIG. 4 is a view in frontal perspective of the preferred embodiment of the invention.

FIG. 5 is a view in perspective of the upper die of the embodiment of FIG. 4.

FIG. 6 is a view in perspective of a portion of a lower die of the embodiment of FIG. 4 with an assembled actuator, catch punch and a support bracket removed from the lower die to reveal its structure.

FIG. 7 is a view in perspective looking the opposite direction at the structures illustrated in FIG. 6.

FIG. 8 is a view in side elevation of a segment of the die of FIG. 6 with the catch punch, support bracket and actuator removed to reveal the passage through which the catch punch extends and retracts.

FIG. 9 is a view in perspective showing in greater detail a portion of the upper die illustrated in FIG. 4.

FIGS. 10-12 are vertical sectional views of the dies of the embodiment of FIG. 4 closed upon a paperboard sheet and showing the actuator, catch punch and cavity at sequential stages of operation.

FIGS. 13 and 14 are views in axial section like those of FIGS. 10-12 but enlarged to reveal more detail of segments of the structure illustrated in FIGS. 10-12.

FIG. 15 is a view in perspective of a container component part embodying the invention but shown upside down.

FIG. 16 is a view in perspective of a segment of the container component part of FIG. 15 shown right side up in the orientation for its normal use as a cake plate.

In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

DETAILED DESCRIPTION OF THE INVENTION

The present invention utilizes standard pressforming or thermoforming dies as is well known in the art of thermoforming or pressforming of paperboard materials. The dies consist primarily of a heated female cavity die, heated male punch die and may also include a heated draw ring and/or an ironing ring but the dies are modified in accordance with the invention. A blank of paperboard material is precut from a roll or sheet of paperboard and is inserted between the male and female dies as in existing technology. The paperboard material is bent and at places small folds are made to conform the paperboard to the forming surfaces of the dies.

FIGS. 1-3 show a relatively simple embodiment of the invention illustrating the principles of its operation and FIGS. 4-14 show the preferred embodiment of the invention. Referring to FIGS. 1-3, only half of the dies and the paperboard blank are illustrated because the other half is a contiguous, mirror image. A male die 10 is shown engaged with a female die 12 with an interposed paperboard sheet 14 pressed between the dies and with a draw ring 15 also pressing a peripheral flange portion of the paperboard sheet 14 against the female die 12. The paperboard sheet 14 is formed by the dies into a first paperboard container component part that has a closing or end panel 18, an axially extending flange 20 and an open end that is facing downwardly in FIGS. 1-3. The interior of the axially extending flange 20 is formed by a male wall die portion 22 of the male die 10 and the exterior of the axially extending flange 20 is formed by a female wall die portion 24 of the female die 12 radially outwardly from the male portion 22.

In order to form catch tabs on the axially extending flange 20, cooperating structures are provided to accomplish a secondary and generally radially acting punching operation while the paperboard sheet 14 is held between the dies 10 and 12. In the embodiment of FIGS. 1-3, a peripheral groove 26 encircles the male die portion 22. A peripheral groove is easier to machine into the die portion but, instead, a plurality of individual cavities can be circumferentially spaced around and formed in the male die portion 22 preferably at regular angular intervals, such as every 45° or every 90° for example. In effect, a peripheral groove forms a unitary series of groove segments, each segment being a cavity. Each cavity opens toward the oppositely facing female die portion 24 of the female die 12. The groove 26, and therefore each segmental cavity, has a shearing edge 28 formed at the edge of its upper surface in FIGS. 1-3.

A plurality of radial passages, only radial passage 30 being visible in FIGS. 1-3, extend through the female die portion 24 with each passage aligned in registration with one of said cavities. A plurality of catch punches, only catch punch 32 being visible in FIGS. 1-3, are mounted for radial movement through a radial passage and into an associated one of the cavities. For example, catch punch 32 is radially slidable through radial passage 30 into cavity 26. Each catch punch includes a shearing edge, only shearing edge 34 being visible in FIGS. 1-3. The shearing edge 34 of the catch punch 32, like the shearing edges of all the catch punches, is aligned to closely slide past the shearing edge 28 of its associated cavity in the manner of a pair of shears.

An actuator, only actuator 36 being visible in FIGS. 1-3, is drivingly linked to each catch punch for driving the catch punches through the radial passages and into the cavities and then retracting the catch punches while the dies 10 and 12 are engaged against the paperboard 18. The shearing edges shear a slit in the interposed paperboard and also drive a segment of paperboard that is adjacent the slit into the cavity to form the catch tab or a preform of it. Preferably, the ends of the catch punches are beveled and the shearing edge of each catch punch is formed on the most distally protruding end of each catch punch to form a knife edge. In the preferred embodiments, the slit is aligned in a circumferential direction of the container component part formed by the paperboard sheet 18. Also, in the preferred embodiments, the catch punches, like the catch punch 32, deforms the paperboard by bending the paperboard to form the catch tab 38 on the side of the slit that is nearer the open end of the container component part being formed. That causes the catch tab 38 to be inclined toward the closed end so that, when two container component parts are engaged together, the catch tab will more firmly resist separation of the two component parts. However, the relative positions of the slit and the catch tab can be reversed.

In operation, the dies 10 and 12, along with the draw ring 15 are pressed against opposite sides of the paperboard sheet 18 as illustrated in FIG. 1. The draw ring can be considered a die because it also presses against the paperboard sheet 18 and can have contoured surfaces to reshape the paperboard sheet. The catch punch 32 is then driven through the passage 30 and into the cavity 26, as illustrated in FIG. 2, to slit the paperboard and bend a small segment of the paperboard inwardly to form the catch tab 38. The catch punch 32 is then retracted out of the cavity and preferably back to its initial position. The dies then begin separation which, for the embodiment illustrated in FIG. 3, is done by lowering the male punch or die 10. As it lowers, the upper shearing edge 28 of the cavity 26 catches the catch tab 38 and bends it, as shown in FIG. 3, further inwardly, downwardly and toward the open end of the container component part being formed. Although shearing edges can also be formed on the lateral sides of the cavity and cooperating shearing edges formed on the lateral sides of the catch punch, that is not necessary. When the edge of the cavity catches on the catch tab and bends it inwardly, this bending of the catch tab will cause a tearing of the paperboard at the opposite ends of the slit. These tears define and form the laterally opposite sides of the catch tab.

Preferably, the forming surface of the die portion into which each cavity is formed is an inclined surface as illustrated in FIG. 1-3 that is inclined or oblique to the central axis of the dies. For forming inwardly bent catch tabs with radially inwardly actuated catch punches, the surface is inclined toward the axial center of the dies as the surface approaches the opposite mating die. The shearing edge of the cavity is formed on the cavity edge nearest the mating die but is preferably spaced radially inwardly from the opposite edge of the cavity by a distance that is less than the distance of protrusion of the catch tabs. That spacing assures that, upon separation of the die portions, the shearing edge of the cavity will catch so it can bend the catch tabs toward the open end of the container component part. Inclining the surface also helps assure that the shearing edge of the cavity will not shear off the tab at its bend as the dies separate. The amount of the incline also controls the distance that the tab is bent back as the dies separate. Paperboard has substantial resilience and therefore a catch tab that bends even beyond a 90° bend will, for most paperboard materials, return to extend toward the closed end of the container component part.

Several variations and modifications may additionally be made. The catch punch does not need to go all the way into the cavities. It must only go far enough to shear the slit into the paperboard and bend the tab inwardly, preferably far enough so that the tab will catch on the cavity edge as the dies separate. If an embodiment is designed so that the punch entirely enters the cavity, the punch needs to be thinner in the axial direction than the cavity in that direction to avoid shearing the catch tab at two opposite edges.

If the invention is applied to form outwardly bent tabs, the cavity, passage and punch positions and the incline would be reversed.

It is not necessary that the movement of the catch punches, and therefore the alignment of the cavities and the passage through which the punch travels, always be in a perfectly radial direction. For example, the catch punches can travel a path that is inclined to the horizontal plane so their travel paths are oblique instead of perpendicular to the axes of the dies. The travel paths can lie along a cone having its axis coaxial with the axis of the dies. It is only necessary that the travel path of the catch punches have a radial component.

The cavities into which the catch punches extend to form the slit and bend the catch tab are not necessarily bounded on all sides. All that is necessary is a shoulder to form a shearing edge. Consequently, instead of the two sided groove illustrated in FIGS. 1-3, the groove could extend (downwardly in the figures) all the way to the paperboard and thereby form only a shoulder at which the shearing edge is formed. It will be apparent to those skilled in the art that this has the disadvantage of reducing the forming surface area of the die. However, for some container component part configurations, the lost forming surface may not be necessary.

A unique aspect of this invention is that it provides a system of extending/retracting punches or knives in the sidewall of a die that may include a draw ring or ironing ring. One of these is provided for each individual catch tab. These could range in number from two to several depending upon the size of the container and lid and there can be upwards of 30 or 40 of these catch tabs. These punches are timed to extend via actuators, such as air cylinders, using a PLC control and a solenoid valve when the die has been closed on the paperboard.

A second unique aspect of this invention is the cavity that is cut into the sidewall of the die forming half which is placed precisely to accept the extending punch with little or no clearance, thereby allowing the punch to penetrate the paperboard material which is sandwiched between the punch and the cavity. This action in and of itself does not necessarily entirely form the catch tab, but at least slits the paperboard and indents it slightly toward the inside of the cavity. As the die opens and the formed paperboard part begins to eject off of the male die, these protruding slits get “caught” on the sharp lip of the cavity, bending them away as the part continues to lift off the die, thereby forming catch tabs that can be used to hold a mating container component part tightly to itself.

FIGS. 4-9 illustrate the preferred embodiment of the invention. Referring to FIG. 4, a pair of dies 40 and 42 are mounted to a die press having a base 44 and an upper die support 46 mounted to vertical columns 48. At least the upper or lower dies are vertically movable along the axis of the dies 40 and 42 to bring the dies into engagement in the conventional manner. The axis for the preferred embodiment is a vertical axis of symmetry for the dies 40 and 42. The upper die 40 is also illustrated FIG. 5 and consists of a cavity insert 50 and an ironing ring 52 which are independently movable toward the lower die 42. The lower die 42 consists of a punch 54 and a draw ring 56 which are also independently movable.

FIGS. 6-8 and 9-11 illustrate more details of the lower die 42. The punch 54 has a convex, dished shape with an outer, convex, rounded shoulder 60. The draw ring 56 closely surrounds the punch 54 and has an interior, concave, rounded shoulder 62. As shown in FIG. 4, eight actuators 64, preferably pneumatic actuators, are mounted to the draw ring 56 at 45° angular intervals. They are operated by air under pressure supplied through air hoses 65 (FIG. 4). Each actuator 64 is fixed to a mounting bracket 66 that in turn is mounted by two cap screws to the draw ring 56. A catch punch 68 is slidably mounted within each mounting bracket 66 and is drivingly linked to an actuator 64 for extending and retracting the catch punch 68. Eight radial passages 70 are formed through the draw ring 56 in alignment with the catch punches 68 and are sufficiently large to permit the beveled, innermost ends of the catch punches 68 to pass through the draw ring 56.

Referring to FIGS. 9-14, the cavity insert 50 has a dish shaped forming surface with a peripheral, rounded ridge 71. The outer surface 73 of the peripheral ridge 71 is inclined to the axis of the dies 40 and 42 and has eight cavities 72 formed to extend into the peripheral ridge 71. This outer, inclined surface 73 together with the concave shoulder 62 on the draw ring 56 form the axially extending flange 78 on the paperboard container component part 80 into which the catch punches 68 are driven to form the catch tabs 82. Each cavity 72 is associated with a passage and a catch punch and is positioned to come into registration with a passage 72 and receive a catch punch 68 when extended by its associated actuator 64. Each cavity also is formed with a shearing edge 74 that cooperates with a shearing edge 76 on each catch punch to cut a circumferentially aligned slit in the paperboard sheet.

The embodiment of FIGS. 4-14 was used to construct the paperboard cake plate illustrated in FIGS. 15 and 16. The cake plate has a peripheral groove 84 formed by a double bend and includes an outer, axially extending flange 78 through which inwardly extending catch tabs 82 were formed. These catch tabs 82 latch over the peripheral flange that extends outwardly from a conventional, disposable cake cover (not illustrated). These catch tabs 82 were formed in the manner illustrated in FIGS. 10-14. The paperboard sheet 80 was compressed between the dies 40 and 42 in the conventional manner while the catch punch was in its retracted position illustrated in FIG. 10. With the dies 40 and 42 held stationary, the catch punch 68 was driven by the actuator 64 along the passage 70 and into the cavity 72. As with the embodiment of FIGS. 1-3, the shearing edges of the cavity 72 and the catch punch 68 shear the paperboard sheet 80 to form a slit and drive a segment of the paperboard 80 into the cavity 72. The actuator 64, or a spring, then retracts the catch punch 68 and leaves the catch tab 82 protruding into the cavity 72 as illustrated in FIG. 12 and the enlarged segment of it illustrated in FIG. 13. The cavity insert 50 is then raised while the ironing ring 52 holds the paperboard 80 against the punch 54 and draw ring 56 of the lower die 42. As it raises, the lower shearing edge 74 of the cavity 72 lifts the segment of paperboard next to the slit, tearing it at opposite ends of the slit to form the catch tab 82.

The terms male die, female die, punch and cavity insert are used to describe the forming dies with mating surfaces that engage an interposed sheet for bending contours into the sheet. However, a die can have multiple components each with some forming function. For example, in the embodiment described above, the lower die consists of a die punch and a draw ring and the upper die consists of a die cavity and an ironing ring. The term die is used herein to refer any of the structures that have forming surfaces whether there are one or multiple components.

Those skilled in the art will also recognize that the locations of the upper and lower dies can be interchanged and that the catch punch structures can be mounted on either the upper or lower dies. Similarly, either one or more of the upper die components can be lowered to engage the lower die components and raised to separate from them or one or more of the lower die components can be raised to engage the upper die components and lowered to separate. Both upper and lower die components could be moved toward the other but this would ordinarily require unnecessary extra equipment. The invention can be practiced with all these variations.

Furthermore, a die can have both male and female forming surfaces on the same die. For example, a circular double bend can be formed at the peripheral edge of a paperboard sheet as described above. The double bend appears on one side of a paperboard sheet as a trough encircling a central panel and on the other side of the sheet as a circular wave having an inner side, an outer side and a crest rising above the central panel. Each die for forming such a double bend has a portion that protrudes into the other die and therefore the descriptive terms male and female are not clearly applicable. When one or both dies are made of multiple components, one component may be male and one female on the same die. Therefore, the term “die portion” is used, without being designated male or female, to refer to a portion of a die that includes a forming surface.

The term “radial” is not intended to be limited to the radials of circular container component parts. Container component parts are often oval or rectangular with rounded edges. Therefore the term “radial” is intended to refer to a direction generally transverse or normal to the flanges, sidewalls or lips of the container component parts.

The cavities that receive the catch punches to form the catch tabs and the catch punches have been described as having a shearing edge. It is not essential that the shear edges be linear. For example, the shear edges of both the catch punch and the cavity can be matingly curved or arcuate, mating sawtooth configurations or other shapes. They can also be aligned somewhat transverse to a plane that is perpendicular to the axes of dies.

It is also not necessary that the cavities be located inwardly of the passages in which the catch punches slide in order to bend the catch tabs to extend inwardly. That configuration is preferred because there is more space outwardly of the dies for positioning of the catch punches and their actuators and because inwardly extending catch tabs are more commonly used. However, the cavities can be formed in the outer die portion with the passages and catch punches inwardly of the cavities so that the catch tabs can be bent outwardly. To do this, it would be desirable to use linkages connecting one or more actuators to the catch punches so the actuators can be positioned where there is adequate space.

While certain preferred embodiments of the present invention have been disclosed in detail, it is to be understood that various modifications may be adopted without departing from the spirit of the invention or scope of the following claims.

Claims

1. A method for forming catch tabs on an axially extending flange of a first paperboard container component part during the pressforming of the first container component between a pair of mating dies, the container component part having a closed end and an open end for engaging a second container component part, the method comprising:

(a) shearing a plurality of circumferentially spaced slits through the axially extending flange; and

(b) radially punching the paperboard adjacent each slit to deform a segment of the paperboard adjacent the slit in a radial direction to form the catch tabs.

2. A method in accordance with claim 1 and further comprising shearing the spaced slits along a circumferential direction and punching and radially deforming the paperboard on the open end side of the slit.

3. A method in accordance with claim 2 wherein the shearing and punching operations are performed in a single operation by driving a shearing punch member radially through openings in said dies.

4. A method in accordance with claim 3 wherein the shearing punch member is driven in a radially inwardly direction to perform the punching and shearing operation and then withdrawn.

5. A method in accordance with claim 1 or 2 or 3 or 4 and further comprising catching each catch tab on an edge formed on one of the dies as the dies are separated and bending the catch tab toward the open end of the container component part.

6. A method in accordance with claim 5 and further comprising tearing the paperboard at opposite ends of the slit during the bending step so that tears form opposite sides of the catch tab.

7. A paperboard container component having catch tabs made in accordance with the method of claim 1 or 2 or 3 or 4

8. A die set apparatus for forming catch tabs on an axially extending flange of a first paperboard container component part having an open end for engaging a second container component part, the catch tabs being formed while a sheet of paperboard is being pressed to form the first container component between a pair of mating dies, the mating dies including a male die portion for pressforming the interior surface of the axially extending flange and a female portion for pressforming the exterior surface of the axially extending flange radially outwardly from the male portion, the apparatus comprising:

(a) a plurality of cavities circumferentially spaced around a first one of said die portions, each cavity opening toward the second of said die portions and having a shearing edge;

(b) a plurality of radial passages extending through the second of said die portions, each passage in registration with one of said cavities;

(c) a plurality of catch punches, each punch mounted for radial movement through a radial passage and into an associated one of the cavities, each catch punch including a shearing edge aligned to closely slide past the shearing edge of its associated cavity; and

(d) an actuator drivingly linked to each catch punch for driving the catch punches into the cavities and thereby shearing a slit in the interposed paperboard and driving an adjacent segment of paperboard into the cavity to form the catch tab.

9. An apparatus in accordance with claim 8 wherein the shearing edges of the catch punch and the cavity are positioned on the respective edges of both each catch punch and each cavity that are closer to the closed end of the container component part.

10. An apparatus in accordance with claim 9 wherein a cavity entering end of each catch punch has a beveled end and a distally protruding edge of the beveled end forms a knife edge as the shearing edge of the punch.

11. An apparatus in accordance with claim 8 or 9 or 10 wherein the first portion having the cavities is inward of the second portion having the radial passages and wherein the catch punches are retractable outwardly where they are disengaged from the cavities and are extendible radially inwardly into the cavities to form the catch tabs.

12. An apparatus in accordance with claim 8 or 9 or 10 wherein the cavities are formed by segments of a continuous groove extending around the first die portion.

13. An apparatus in accordance with claim 8 or 9 or 10 wherein each cavity is formed into an inclined surface of the first die portion, the inclined surface being inclined toward the axial center of the dies as the inclined surface approaches the mating die, the shearing edge of the cavity being formed on the cavity edge nearest the mating die but spaced radially inwardly from an opposite edge of the cavity less than the distance of protrusion of the catch tabs so that, upon separation of the die portions, the shearing edge of the cavity will catch and bend the catch tabs toward the open end of the container component part.

14. An apparatus in accordance with claim 8 or 9 or 10 wherein each cavity has a bending edge axially opposite the shearing edge and wherein the catch punch has an axial thickness that is less than the axial distance from the shearing edge of the cavity to the bending edge of the cavity to avoid shearing the paperboard at both edges.

15. An improved container component part having at least one axially extending flange with catch tabs protruding from the flange, wherein the improvement comprises:

the container component part being formed of a unitary sheet of pressformed paperboard.