Patent Description:
Metallic containers (e.g., cans) for holding products such as, for example, food and beverages, are typically provided with an easy open can end on which a pull tab is attached (e.g., without limitation, riveted) to a tear strip or severable panel. The severable panel is defined by a scoreline in the exterior surface (e.g., public side) of the can end. The pull tab is structured to be lifted and/or pulled to sever the scoreline and deflect and/or remove the severable panel, thereby creating an opening for dispensing the contents of the can.

When the can end is made, it originates as a can end shell, which is formed from a blank cut (e.g., blanked) from a sheet metal product (e.g., without limitation, sheet aluminum; sheet steel). The shell is then conveyed to a conversion press, which has a number of successive tool stations. As the shell advances from one tool station to the next, conversion operations such as, for example and without limitation, rivet forming, paneling, scoring, embossing, tab securing and tab staking, are performed until the shell is fully converted into the desired can end and is discharged from the press.

In the can making industry, large volumes of metal are required in order to manufacture a considerable number of cans. Thus, an ongoing objective in the industry is to reduce the amount of metal that is consumed. Efforts are constantly being made, therefore, to reduce the thickness or gauge (sometimes referred to as "down-gauging") of the stock material from which can ends and can bodies are made. However, as less material (e.g., thinner gauge) is used, problems arise that require the development of unique solutions. There is, therefore, a continuing desire in the industry to reduce the gauge and thereby reduce the amount of material used to form such containers. However, among other disadvantages associated with the formation of can ends from relatively thin gauge material, is the tendency of the can end to wrinkle, for example, during forming of the shell.

Prior proposals for reducing the volume of metal used reduce the blank size for the can end, but sacrifice the area of the end panel. This undesirably limits the available space, for example, for the scoreline, the severable panel and/or the pull tab.

There is, therefore, room for improvement in containers such as beer/beverage cans and food cans, as well as in selectively formed can ends or shells and tooling and methods for providing such can ends or shells.

<CIT> discloses a container, and selectively formed shell, and tooling and associated method for providing same.

These needs and others are met by the present invention, which is directed to a tooling as set forth in claim <NUM>.

For an understanding of the disclosed concept, a shell is structured to be affixed to a container. The shell comprises: a center panel; a circumferential chuck wall; an annular countersink between the center panel and the circumferential chuck wall; and a curl extending radially outwardly from the chuck wall. The material of at least one predetermined portion of the shell is selectively stretched relative to at least one other portion of the shell, thereby providing a corresponding thinned portion.

The shell may be formed from a blank of material, wherein the blank of material has a base gauge prior to being formed, and wherein, after being formed, the material of the shell at or about the thinned portion has a thickness. The thickness of the material at or about the thinned portion is less than the base gauge. The thinned portion may include the chuck wall.

Also for an understanding of the disclosed concept, the shell is formed by a method. The method comprises: introducing material between tooling, forming the material to include a center panel, a circumferential chuck wall, an annular countersink between the center panel and the circumferential chuck wall, and a curl extending radially outwardly from the chuck wall, and selectively stretching at least one predetermined portion of the shell relative to at least one other portion of the shell to provide a corresponding thinned portion of the shell.

The method may comprise the step of converting the shell into a finished can end. The method may further comprise the step of seaming the finished can end onto a container body.

According to the disclosed concept, tooling is provided for forming a shell. The tooling comprises: an upper tool assembly; and a lower tool assembly cooperating with the upper tool assembly to form material disposed therebetween to include a center panel, a circumferential chuck wall, an annular countersink between the center panel and the circumferential chuck wall, and a curl extending radially outwardly from the chuck wall. The upper tool assembly and the lower tool assembly cooperate to selectively stretch the material of at least one predetermined portion of the shell relative to at least one other portion of the shell, thereby providing a corresponding thinned portion.

Selectively thinning a predetermined portion of the shell relative to at least one other portion of the shell to provide a corresponding thinned portion of the shell has been determined to create certain complications such as an overloading condition on the tooling and/or press. Further, the selective thinning may result in excessively uneven thinning. That is, while some unevenness in the thinning is acceptable, excessive uneven thinning is not desirable. It is desirable that the selective thinning be accomplished with existing presses. There is, therefore, room for improvement in the tooling.

These needs and others are met by the disclosed concept, which is directed to a tooling including a force and/or pressure concentrating forming surface and/or a hybrid bias generating assembly. In an exemplary embodiment, the hybrid bias generating assembly is one of an active hybrid bias generating assembly or a selectable hybrid bias generating assembly, as defined below. It is understood that, in the known art, to increase the pressure acting on a shell, manufacturers simply increased the pressure acting on the tooling. This increase in pressure created a counter load that was applied to the press. As disclosed herein, concentrating the force/pressure on a forming surface allows for reduced counter loads to be applied to the press. An increase in the pressure surface area of the upper surface of the upper tool assembly and a reduction in the forming surface area that clamps the blanks solves the stated problem. In an exemplary embodiment, the concentrating forming surface allows for a ratio of the total bias pressure to the clamping pressure of between about <NUM>:<NUM> to <NUM>:<NUM>, or between about <NUM>:<NUM> and <NUM>:<NUM>, or about <NUM>:<NUM>. That is, a total bias pressure is applied to a pressure surface and the resulting pressure at the clamping surface is between about <NUM> to <NUM>, or between about <NUM> and <NUM>, or about <NUM> times greater. Such ratios of total bias pressure to the clamping pressure allows for a reduction in the loading condition on the tooling and/or press and therefore solves the stated problem. Further, the use of a hybrid bias generating assembly prevents an excessive amount of uneven thinning and therefore solves the stated problem.

In an exemplary embodiment, an upper tool assembly piston includes a piston that is coupled to an upper pressure sleeve. The piston includes an upper side that is exposed to a pressure. The upper pressure sleeve includes a lower forming surface. The area ratio of the upper tool assembly piston upper side to the upper pressure sleeve lower forming surface is between about <NUM>:<NUM> to <NUM>:<NUM>, <NUM>:<NUM> and <NUM>:<NUM>, or about <NUM>:<NUM>. A tool assembly with this area ratio solves the problems stated above. That is, as shown in <FIG>, in the known art, the ratio of the area of the upper tool assembly piston upper side to the upper pressure sleeve lower forming surface is about <NUM>:<NUM>. This ratio, compared to the disclosed concept, includes a smaller upper tool assembly piston upper side and a large upper pressure sleeve lower forming surface. It is noted that, in this configuration, the metal is not thinned, as discussed above. As shown in in <FIG>, and in an exemplary embodiment, the ratio of the area of the upper tool assembly piston upper side to the upper pressure sleeve lower forming surface is about <NUM>:<NUM>. An upper tool assembly having the configuration of the disclosed concept is a force concentrating, and/or pressure concentrating, forming surface that solves the stated problems.

A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:.

For purposes of illustration, embodiments of the disclosed concept will be described as applied to shells for a can end known in the industry as a "B64" end, although it will become apparent that they could also be employed to suitably selectively stretch and thin predetermined portions or areas of any known or suitable alternative type (e.g., without limitation, beverage/beer can ends; food can ends) and/or configuration other than B64 ends.

It will be appreciated that the specific elements illustrated in the figures herein and described in the following specification are simply exemplary embodiments of the disclosed concept, which are provided as non-limiting examples solely for the purpose of illustration.

Directional phrases used herein, such as, for example, clockwise, counterclockwise, left, right, top, bottom, upwards, downwards and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.

As used herein, the singular form of "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

As used herein, the statement that two or more parts or components are "coupled" shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, "directly coupled" means that two elements are directly in contact with each other. It is noted that moving parts, such as but not limited to circuit breaker contacts, are "directly coupled" when in one position, e.g., the closed, second position, but are not "directly coupled" when in the open, first position. As used herein, "fixedly coupled" or "fixed" means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other. Accordingly, when two elements are coupled, all portions of those elements are coupled. A description, however, of a specific portion of a first element being coupled to a second element, e.g., an axle first end being coupled to a first wheel, means that the specific portion of the first element is disposed closer to the second element than the other portions thereof.

As used herein, the phrase "removably coupled" means that one component is coupled with another component in an essentially temporary manner. That is, the two components are coupled in such a way that the joining or separation of the components is easy and would not damage the components. For example, two components secured to each other with a limited number of readily accessible fasteners are "removably coupled" whereas two components that are welded together or joined by difficult to access fasteners are not "removably coupled. " A "difficult to access fastener" is one that requires the removal of one or more other components prior to accessing the fastener wherein the "other component" is not an access device such as, but not limited to, a door.

As used herein, "operatively coupled" means that a number of elements or assemblies, each of which is movable between a first position and a second position, or a first configuration and a second configuration, are coupled so that as the first element moves from one position/configuration to the other, the second element moves between positions/configurations as well. It is noted that a first element may be "operatively coupled" to another without the opposite being true.

As used herein, a "coupling assembly" includes two or more couplings or coupling components. The components of a coupling or coupling assembly are generally not part of the same element or other component. As such, the components of a "coupling assembly" may not be described at the same time in the following description.

As used herein, a "coupling" or "coupling component(s)" is one or more component(s) of a coupling assembly. That is, a coupling assembly includes at least two components that are structured to be coupled together. It is understood that the components of a coupling assembly are compatible with each other. For example, in a coupling assembly, if one coupling component is a snap socket, the other coupling component is a snap plug, or, if one coupling component is a bolt, then the other coupling component is a nut.

As used herein, "correspond" indicates that two structural components are sized and shaped to be similar to each other and may be coupled with a minimum amount of friction. Thus, an opening which "corresponds" to a member is sized slightly larger than the member so that the member may pass through the opening with a minimum amount of friction. This definition is modified if the two components are to fit "snugly" together. In that situation, the difference between the size of the components is even smaller whereby the amount of friction increases. If the element defining the opening and/or the component inserted into the opening are made from a deformable or compressible material, the opening may even be slightly smaller than the component being inserted into the opening. With regard to surfaces, shapes, and lines, two, or more, "corresponding" surfaces, shapes, or lines have generally the same size, shape, and contours.

As used herein, and in the phrase "[x] moves between a first position and a second position corresponding to [y] first and second positions," wherein "[x]" and "[y]" are elements or assemblies, the word "correspond" means that when element [x] is in the first position, element [y] is in the first position, and, when element [x] is in the second position, element [y] is in the second position. It is noted that "correspond" relates to the final positions and does not mean the elements must move at the same rate or simultaneously. That is, for example, a hubcap and the wheel to which it is attached rotate in a corresponding manner. Conversely, a spring biased latched member and a latch release move at different rates. Thus, as stated above, "corresponding" positions mean that the elements are in the identified first positions at the same time, and, in the identified second positions at the same time.

As used herein, the statement that two or more parts or components "engage" one another shall mean that the elements exert a force or bias against one another either directly or through one or more intermediate elements or components. Further, as used herein with regard to moving parts, a moving part may "engage" another element during the motion from one position to another and/or may "engage" another element once in the described position. Thus, it is understood that the statements, "when element A moves to element A first position, element A engages element B," and "when element A is in element A first position, element A engages element B" are equivalent statements and mean that element A either engages element B while moving to element A first position and/or element A either engages element B while in element A first position.

As used herein, "operatively engage" means "engage and move. " That is, "operatively engage" when used in relation to a first component that is structured to move a movable or rotatable second component means that the first component applies a force sufficient to cause the second component to move. For example, a screwdriver may be placed into contact with a screw. When no force is applied to the screwdriver, the screwdriver is merely "coupled" to the screw. If an axial force is applied to the screwdriver, the screwdriver is pressed against the screw and "engages" the screw. However, when a rotational force is applied to the screwdriver, the screwdriver "operatively engages" the screw and causes the screw to rotate.

As used herein, the word "unitary" means a component that is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a "unitary" component or body.

As used herein, "structured to [verb]" means that the identified element or assembly has a structure that is shaped, sized, disposed, coupled and/or configured to perform the identified verb. For example, a member that is "structured to move" is movably coupled to another element and includes elements that cause the member to move or the member is otherwise configured to move in response to other elements or assemblies. As such, as used herein, "structured to [verb]" recites structure and not function. Further, as used herein, "structured to [verb]" means that the identified element or assembly is intended to, and is designed to, perform the identified verb. Thus, an element that is merely capable of performing the identified verb but which is not intended to, and is not designed to, perform the identified verb is not "structured to [verb]. " As used herein, "associated" means that the elements are part of the same assembly and/or operate together, or, act upon/with each other in some manner. For example, an automobile has four tires and four hub caps. While all the elements are coupled as part of the automobile, it is understood that each hubcap is "associated" with a specific tire.

As used herein, in the phrase "[x] moves between its first position and second position," or, "[y] is structured to move [x] between its first position and second position," "[x]" is the name of an element or assembly. Further, when [x] is an element or assembly that moves between a number of positions, the pronoun "its" means "[x]," i.e. the named element or assembly that precedes the pronoun "its.

As employed herein, the terms "can" and "container" are used substantially interchangeably to refer to any known or suitable container, which is structured to contain a substance (e.g., without limitation, liquid; food; any other suitable substance), and expressly includes, but is not limited to, beverage cans, such as beer and soda cans, as well as food cans.

As employed herein, the term "can end" refers to the lid or closure that is structured to be coupled to a can, in order to seal the can.

As employed herein, the term "can end shell" is used substantially interchangeably with the term "can end. " The "can end shell" or simply the "shell" is the member that is acted upon and is converted by the disclosed tooling to provide the desired can end.

As employed herein, the terms "tooling," "tooling assembly" and "tool assembly" are used substantially interchangeably to refer to any known or suitable tool(s) or component(s) used to form (e.g., without limitation, stretch) shells in accordance with the disclosed concept.

As employed herein, the term "fastener" refers to any suitable connecting or tightening mechanism expressly including, but not limited to, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers and nuts.

As employed herein, the term "number" shall mean one or an integer greater than one (i.e., a plurality).

<FIG> show a can end shell <NUM> that is selectively formed. Specifically, as described in detail herein below, the material in certain predetermined areas of the shell <NUM>, has been stretched, thereby thinning it, whereas other areas of the shell <NUM> preferably maintain the base metal thickness. Although the example shown and described herein refers to a shell (see, for example and without limitation, shell <NUM> of <FIG>, <FIG> and <FIG>) for a beverage can body <NUM> (partially shown in simplified form in phantom line drawing in <FIG>), it will be appreciated that the disclosed concept could be employed to stretch and thin any known or suitable can end shell type and/or configuration for any known or suitable alternative type of container (e.g., without limitation, food can (not shown)), which is subsequently further formed (e.g., converted) into a finished can end for such a container.

The shell <NUM> in the non-limiting example shown and described herein includes a circular center panel <NUM>, which is connected by a substantially cylindrical panel wall <NUM> to an annular countersink <NUM>. The example annular countersink <NUM> has a generally U-shaped cross-sectional profile. A tapered chuck wall <NUM> connects the countersink <NUM> to a crown <NUM>, and a peripheral curl or outer lip <NUM> extends radially outwardly from the crown <NUM>, as shown in <FIG> and <FIG>.

In the non-limiting example of <FIG>, the shell <NUM> has a base metal thickness of about <NUM> (. <NUM> inch). This base metal thickness is preferably substantially maintained in areas such as the center panel <NUM> and outer lip or curl <NUM>. Keeping the center panel <NUM> in the base metal thickness helps with rivet, score and tab functions in the converted end (not explicitly shown). For example and without limitation, undesirable issues such as wrinkling and/or undesired scoreline and/or rivet or tab failures that can be attributed to reduced strength associated with thinned metal, are substantially eliminated by substantially maintaining the base thickness in the panel <NUM>. Similarly, substantially maintaining the outer lip <NUM> at base gauge helps with the seaming ability, for seaming the lid or can end <NUM> to the can body <NUM> (partially shown in simplified form in phantom line drawing in <FIG>). This area where preferably minimal to no thinning occurs, is indicated generally in <FIG> by reference <NUM>.

Accordingly, the majority of the thinning (e.g., without limitation, between <NUM>-<NUM>%, or about <NUM>%, thinning) preferably occurs in the chuck wall <NUM>. More specifically, thinning preferably occurs in the area between the crown <NUM> and the countersink <NUM>, which is generally indicated as area <NUM> in <FIG>. Thus, by way of illustration, in the non-limiting example of <FIG>, the thickness of the material in the chuck wall <NUM> may be reduced to about <NUM> (. <NUM> inch). It will be appreciated that this is a substantial reduction, which results in significant weight reduction and cost savings over conventional can ends.

It will further be appreciated that the particular shell type and/or configuration and/or dimensions shown in <FIG> (and all of the figures provided herein) are provided solely for purposes of illustration and are not limiting on the scope of the disclosed concept. That is, any known or suitable alternative thinning of the base gauge could be implemented in additional and/or alternative areas of the shell (e.g., without limitation, <NUM>) for any known or suitable shell, or end type and/or configuration, without departing from the scope of the disclosed concept.

Moreover, the disclosed concept achieves material thinning and an associated reduction in the overall amount and weight of material, without incurring increased material processing charges associated with the stock material that is supplied to form the end product. For example and without limitation, increased processing (e.g., rolling) of the stock material to reduce the base gauge (i.e., thickness) of the material can undesirably result in a relatively substantial increase in initial cost of the material. The disclosed concept achieves desired thinning and reduction, yet uses stock material having a more conventional and, therefore, less expensive base gauge.

<FIG> show various tooling assemblies <NUM> (or "tooling <NUM>") for stretching and thinning the shell material, in accordance with one non-limiting example embodiment of the disclosed concept. Specifically, the selective forming (e.g., stretching and thinning) is accomplished by way of precise tooling geometry, placement and interaction. In accordance with one non-limiting embodiment, the process begins by introducing a blank of material (see, for example and without limitation, blank <NUM> of <FIG>) having a base metal thickness or gauge, between components of a tooling assembly <NUM>.

<FIG> illustrates a single station <NUM>, also known as a "pocket" <NUM>, of a multiple station tooling assembly <NUM> coupled to a press <NUM>. For example and without limitation, typically one shell <NUM> is produced at each station <NUM> during each stroke of a conventional high-speed single-action or double-action mechanical press <NUM> to which the multiple station tooling assembly <NUM> of the disclosed concept is coupled. The tooling assembly <NUM> includes opposing upper and lower tool assemblies <NUM>, <NUM> that cooperate to form (e.g., without limitation, stretch; thin; bend) metal (see, for example and without limitation, metal blank <NUM> of <FIG>) to achieve the desired shell (see, for example, and without limitation, shell <NUM> of <FIG>, <FIG> and <FIG>), in accordance with the disclosed concept.

More specifically, the upper and lower tool assemblies <NUM>, <NUM> are coupled to upper and lower die shoes <NUM>, <NUM>, which are respectively supported by the press bed and/or bolster plates and the ram within the press <NUM> in a generally well known manner. An annular blank and draw die <NUM> includes an upper flange portion <NUM>, which is coupled to a retainer or riser body <NUM> by a number of fasteners <NUM>. The blank and draw die <NUM> surrounds an upper pressure sleeve <NUM>. That is, the blank and draw die <NUM> is proximate to the upper pressure sleeve <NUM> and is located radially outward from the upper pressure sleeve <NUM>. An inner die member or die center <NUM> is supported within the upper pressure sleeve <NUM> by a die center riser <NUM>. The blank and draw die <NUM> includes an inner curved forming surface <NUM> (<FIG> and <FIG>). The lower end <NUM> of the upper pressure sleeve <NUM> includes a contoured annular forming surface <NUM> (<FIG> and <FIG>).

Continuing to refer to <FIG>, an annular die retainer <NUM> is coupled to the lower die shoe <NUM> within a counterbore <NUM>. An annular cut edge die <NUM> is coupled to the die retainer <NUM> by suitable fasteners <NUM>. An annular lower pressure sleeve <NUM> includes a lower piston portion <NUM> for movement within the die retainer <NUM>. The lower pressure sleeve <NUM> further includes an upper end <NUM> having a substantially flat surface which opposes the lower end of the aforementioned blank and draw die <NUM>. The cut edge die <NUM> is located proximate to the lower pressure sleeve <NUM> and radially outward from the upper end <NUM> of the lower pressure sleeve <NUM>, as shown. A die core ring <NUM> is disposed within the lower pressure sleeve <NUM>, and includes an upper end <NUM> that opposes the lower end or forming surface <NUM> of the upper pressure sleeve <NUM>, as best shown in <FIG> and <FIG>. The upper end <NUM> includes a tapered surface <NUM>, a rounded, or curvilinear, inner surface <NUM> and a rounded outer surface <NUM> (all shown in <FIG> and <FIG>). A circular panel punch <NUM> is disposed within the die core ring <NUM> opposite the aforementioned die center <NUM>. The panel punch <NUM> includes a circular, substantially flat upper surface <NUM> having a peripheral rounded surface <NUM>. A peripheral recessed portion <NUM> extends downwardly from the rounded surface <NUM>, as best shown in <FIG> and <FIG>.

Accordingly, the foregoing tools of the upper tool assembly <NUM> and lower tool assembly <NUM> cooperate to form and, in particular, stretch and thin predetermined selected areas of, the shell <NUM>, as will now be described in greater detail with respect to <FIG>, which illustrate the method and associated forming stages for forming the stretched and thinned shell <NUM>.

<FIG> shows a first forming step wherein a blank <NUM> is provided using the aforementioned tooling assembly <NUM> (<FIG>). More specifically, respective cut edges of the blank and draw die <NUM> and annular cut edge die <NUM> cooperate to cut (e.g., blank) the blank <NUM>, for example, from a web or sheet of material. In a second step, shown in <FIG>, the tooling <NUM> cooperates to make a first bend, namely bending the peripheral edges of the blank <NUM> downward, as shown. Next, in the forming step shown in <FIG>, the outer portions of the blank <NUM> are further formed, as shown. This is achieved by the inner curved surface <NUM> of the blank and draw die <NUM> cooperating with the upper end <NUM> of the die core ring <NUM>, and by the forming surface <NUM> of the upper pressure sleeve <NUM> cooperating with the upper end <NUM> of the die core ring <NUM>.

Stretching and thinning in accordance with the aforementioned concept will be further described and understood with reference to the fourth forming step, illustrated in <FIG> and <FIG>. Specifically, <FIG> shows the tooling assembly <NUM> after a down stroke, wherein all of the tools shown have moved downward in the direction of arrows <NUM> to the positions shown. That is, the blank and draw die <NUM> and lower pressure sleeve <NUM> have moved downward in the direction of arrows <NUM> to further form the outer lip or curl <NUM>. The upper pressure sleeve <NUM> has also moved downward in the direction of arrow <NUM>, such that the forming surface <NUM> of the upper pressure sleeve <NUM> cooperates with the upper end <NUM> of the die core ring <NUM> to further form the crown <NUM>, as shown. The die center <NUM>, which also moves downward in the direction of arrow <NUM>, stretches the metal of the blank <NUM> in the area of the chuck wall <NUM> as the substantially flat surface of the lower end of the die center <NUM> clamps the material between the die center <NUM> and the substantially flat upper surface <NUM> of the panel punch <NUM>. The die center <NUM> and panel punch <NUM> both move downward in the direction of arrows <NUM> to stretch and thin the metal in the area of the chuck wall <NUM> as it cooperates with the tapered surface <NUM> of the die core ring <NUM>. Thus, in the fourth forming step, the material of the blank <NUM> is stretched and thinned in the area that will become the chuck wall <NUM>, but little to no stretching or thinning occurs in the outer lip or curl area <NUM>, or in the area that will be later formed into the panel <NUM> (<FIG> and <FIG>) or in the lower area that will be later formed into the annular countersink <NUM> (<FIG> and <FIG>). These areas remain substantially at base gauge metal thickness, as previously discussed hereinabove.

In the fifth and final shell forming step, formation of the shell <NUM> is completed. Specifically, as shown in <FIG>, which illustrates the same tooling assembly <NUM> shown and described hereinabove with respect to the downward stroke of <FIG>, some of the tooling assembly <NUM> has moved upward in <FIG> in the direction of arrows <NUM> to form the panel <NUM> of the shell <NUM>. Specifically, the blank and draw die <NUM>, die center <NUM>, lower pressure sleeve <NUM>, and panel punch <NUM> all move upward in the direction of arrow <NUM>, whereas the upper pressure sleeve <NUM> has stopped moving downward in the direction of arrow <NUM> at this point and is holding pressure on the shell <NUM>. This results in the further formation of the outer lip or curl <NUM> over the rounded outer surface <NUM> of the die core ring <NUM>, as well as the further formation of the crown <NUM> between the forming surface <NUM> of the upper pressure sleeve <NUM> and the upper end <NUM> of the die core ring <NUM>. The desired final form of the chuck wall <NUM> is provided by interaction of the upper pressure sleeve <NUM> and surfaces <NUM> and <NUM> of the die core ring <NUM>. The panel <NUM> is formed by interaction of the substantially flat upper surface <NUM> of the panel punch <NUM> with the die center <NUM> as both of these components move upward in the direction of arrows <NUM> with the metal of the blank <NUM> that becomes the panel <NUM> disposed (e.g., clamped) therebetween. This movement also facilitates the formation of the cylindrical panel wall <NUM> and countersink <NUM>. Specifically, as the panel punch <NUM> moves upward and the upper pressure sleeve <NUM> moves downward, the annular countersink <NUM> is formed within the peripheral recessed portion <NUM> of the panel punch <NUM>. The cylindrical panel wall <NUM> is, therefore, formed as the metal cooperates with the peripheral rounded surface <NUM> of the panel punch <NUM>.

Accordingly, it will be appreciated that the disclosed concept differs substantially from conventional shell forming methods and tooling, wherein the material of the blank <NUM> or shell <NUM> is not specifically stretched or thinned. That is, while the panel <NUM>, countersink <NUM> and outer lip or curl <NUM> portions of the example shell <NUM> (<FIG>, <FIG> and <FIG>) are not stretched or are nominally stretched, the area <NUM> (<FIG>) between the countersink <NUM> and crown <NUM> is stretched and thinned during the forming process and, in particular in the fourth forming step shown in <FIG> and <FIG>.

It will be appreciated that while five forming stages are shown in <FIG>, that any known or suitable alternative number and/or order of forming stages could be performed to suitably selectively stretch and thin material in accordance with the disclosed concept. It will further be appreciated that any known or suitable mechanism for sufficiently securing certain areas of the material to resist movement (e.g., sliding) or flow or thinning of the material while other predetermined areas of the material are stretched and thinned could be employed, without departing from the scope of the disclosed concept. Moreover, alternative, or additional, areas of the shell <NUM> (e.g., without limitation, <NUM>) other than those which are shown and described herein could be suitably stretched and thinned, and the disclosed concept could be applied to stretch shells that are of a different type and/or configuration altogether (not shown).

Accordingly, it will be appreciated that the disclosed concept provides tooling assembly <NUM> (<FIG>) and methods for selectively stretching and thinning predetermined areas (see, for example and without limitation, area <NUM> of <FIG>) of a shell <NUM> (<FIG>, <FIG> and <FIG>), thereby providing relatively substantially material and cost savings.

Another embodiment is shown in <FIG>. Other than the elements discussed below, the tooling 200A is substantially similar to the tooling assembly <NUM> discussed above and like elements will use like reference numbers. As discussed above, and in an exemplary embodiment, the die core ring upper end <NUM> opposes the lower end or forming surface <NUM> of the upper pressure sleeve <NUM>. As further described above, the outer portions of the blank <NUM> are formed by the forming surface <NUM> of the upper pressure sleeve <NUM> cooperating with the upper end <NUM> of the die core ring <NUM>. That is, both the die core ring upper end <NUM> and the upper pressure sleeve forming surface <NUM> engage the blank <NUM>. As used herein, simultaneous engagement by elements disposed in opposition to each other is identified as "clamping.

As noted above, the die core ring upper end <NUM> includes a tapered surface <NUM>, a rounded inner surface <NUM> and a rounded outer surface <NUM>. In an exemplary embodiment, the die core ring upper end <NUM> further includes a generally horizontal surface <NUM>. As used herein, the "generally horizontal surface" <NUM> is that portion of the die core ring upper end that extends in a plane that is generally perpendicular to the axis of motion of the upper and lower tool assemblies <NUM>, <NUM>. As used herein, "generally perpendicular" means perpendicular +/- about <NUM> degrees.

In this exemplary embodiment, the upper tool assembly <NUM> and the lower tool <NUM> assembly move between a separated, first position, wherein the upper tool assembly <NUM> is spaced from the lower tool assembly <NUM>, and a forming position, wherein the upper tool assembly <NUM> is immediately adjacent the lower tool assembly <NUM> to selectively stretch the material of at least one predetermined portion of the shell <NUM> relative to at least one other portion of the shell, thereby providing a corresponding thinned portion. When the upper tool assembly <NUM> and the lower tool <NUM> are in the forming position, the upper pressure sleeve <NUM> and the die core ring <NUM> clamp the shell <NUM>, as described above. The force acting on the blank <NUM> is, as used herein, the "clamping force.

In this exemplary embodiment, the upper tool assembly <NUM> also includes a hybrid bias generating assembly <NUM> and the upper pressure sleeve forming surface <NUM> is a force concentrating forming surface <NUM>. As used herein, a "hybrid bias generating assembly" is an assembly that generates a bias in at least two different manners, and, the bias is applied to the same component. That is, as used herein, a "hybrid bias generating assembly" includes at least two bias generating assemblies that apply bias to the same component as well as a number of hybrid components. Thus, an assembly, such as, but not limited to the hybrid bias generating assembly <NUM> described herein, which generates a bias via a compressed fluid (pressure bias) and via a spring (mechanical bias) satisfies the first requirement of being an active hybrid bias generating assembly. Conversely, a device with a high pressure compressor and a low pressure compressor (both producing pressure bias) is not a "hybrid bias generating assembly" because the manner of producing bias is the same. Further, an assembly wherein one type of bias is applied to one component and another type of bias is applied to a different component is also not an "hybrid bias generating assembly" because the bias is not applied to the same component.

Further, as used herein, an "active hybrid bias generating assembly" is an assembly that includes at least two bias generating assemblies that apply bias to the same component at the same time. Further, as used herein, a "selectable hybrid bias generating assembly" is an assembly that includes at least two bias generating assemblies, and, the bias is selectively applied to the same component. That is, in a "selectable hybrid bias generating assembly" has the capability of applying bias in at least two different manners and the user determines which bias generating assembly, or both, apply bias to a component. Thus, when a user selects two manners of applying bias, the "selectable hybrid bias generating assembly" operates as an "active hybrid bias generating assembly. " Stated alternately, an "active hybrid bias generating assembly" is a type of "selectable hybrid bias generating assembly" but the opposite is not always true. That is, not all "selectable hybrid bias generating assemblies" are "active hybrid bias generating assemblies. " A "selectable hybrid bias generating assembly" that applies bias in only one of several available manners is a "selectable hybrid bias generating assembly" but not an "active hybrid bias generating assembly. " In an exemplary embodiment, the hybrid bias generating assembly <NUM> is one of an active hybrid bias generating assembly <NUM> or a selectable hybrid bias generating assembly <NUM>.

The hybrid bias generating assembly <NUM> includes a pressure generating assembly <NUM>, a mechanical bias assembly <NUM>, and a number of hybrid components <NUM>. As used herein, "hybrid components" <NUM> are components that are structured to be utilized by both bias generating assemblies, in the exemplary embodiment, the pressure generating assembly <NUM> and the mechanical bias assembly <NUM>. The pressure generating assembly <NUM> includes a pressure generating device <NUM> (shown schematically), a pressure communication assembly <NUM> (shown schematically), a pressure chamber <NUM>, and a piston assembly <NUM>. The pressure generating device <NUM> is any known device structured to compress a fluid, or store compressed fluid, at an increased pressure, such as, but not limited to a fluid pump or compressor. The pressure communication assembly <NUM> includes any number of hoses, conduits, passages or any other construct capable of communicating a pressurized fluid. It is understood the pressure communication assembly <NUM> also includes seals, valves or any other construct required to control the communication of a pressurized fluid.

In an exemplary embodiment, the riser body <NUM> is sealingly coupled, directly coupled, or fixed to the upper die shoe <NUM>. In this configuration, the riser body <NUM> defines the pressure chamber <NUM>. It is understood that the pressure chamber <NUM> includes a number of seals, not identified, required to prevent fluid from escaping. The piston assembly <NUM> includes a torus-shaped body <NUM> and, in an exemplary embodiment, a spring seat <NUM>, as discussed below. In another embodiment, not shown, the piston body and the spring seat are a unitary body. It is understood that the description of the piston body <NUM> applicable to the spring seat <NUM> is an embodiment that includes a spring seat <NUM>. For example, the piston body <NUM> corresponds to the pressure chamber <NUM> and the die center riser <NUM>; it is understood that in an embodiment with a spring seat <NUM> the spring seat <NUM> corresponds to the pressure chamber <NUM> and the die center riser <NUM>. Thus, the outer radial surface of the piston body <NUM>, or the spring seat <NUM>, is sealingly coupled to the inner surface of the pressure chamber <NUM>, and, the inner radial surface of the piston body <NUM> is sealingly coupled to the outer surface of the die center riser <NUM>. It is understood that the piston assembly <NUM> includes a number of seals, not identified, required to prevent fluid from escaping the pressure chamber <NUM>. The piston assembly <NUM> is movably disposed in the pressure chamber <NUM>.

The pressure generating device <NUM> is in fluid communication, via the pressure communication assembly <NUM>, with the pressure chamber <NUM>. The fluid, and therefore the pressure associated therewith, is communicated to the upper side of the piston body <NUM>, hereinafter the "pressure surface" <NUM>. It is understood that, in an embodiment with a spring seat <NUM>, the pressure surface <NUM> may be the upper surface of the spring seat <NUM>. In an exemplary embodiment, the total bias force is applied to the pressure surface <NUM> which has an area of between about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), or about <NUM><NUM> (<NUM> in<NUM>). Thus, the pressure generating device <NUM> is structured to control the position of the piston assembly <NUM> in the pressure chamber <NUM>, and is structured to move the piston assembly <NUM> in the pressure chamber <NUM>. The piston assembly <NUM> is coupled to the upper pressure sleeve <NUM>. That is, the upper pressure sleeve <NUM> includes an upper end <NUM> opposite the forming surface <NUM>. The piston assembly <NUM> is coupled to the upper pressure sleeve upper end <NUM>. Thus, as the piston assembly <NUM> moves within the pressure chamber <NUM>, the upper pressure sleeve <NUM> moves between an extended, first position, wherein the upper pressure sleeve lower end <NUM> is more spaced from the upper die shoe <NUM>, and a retracted, second position, wherein the upper pressure sleeve lower end <NUM> is less spaced from the upper die shoe <NUM>.

In this configuration, the piston assembly <NUM> and the piston body <NUM> are "hybrid components" <NUM> as defined herein. That is, the piston assembly <NUM> and the piston body <NUM> are structured to be utilized by both the pressure generating assembly <NUM> and the mechanical bias assembly <NUM>. It is noted that a piston associated exclusively with a pressure generating assembly <NUM> or exclusively with a mechanical bias assembly <NUM> cannot be a "hybrid component" as defined herein. That is, by definition, a piston assembly <NUM> associated exclusively with a pressure generating assembly <NUM> cannot be "structured to" be utilized by both bias generating assemblies. Similarly, by definition, a piston assembly <NUM> associated exclusively with a mechanical bias assembly <NUM> cannot be "structured to" be utilized by both bias generating assemblies. Accordingly, a piston associated exclusively with a pressure generating assembly <NUM> or exclusively with a mechanical bias assembly <NUM> is not a "hybrid component" as used herein.

In an exemplary embodiment, the mechanical bias assembly <NUM> includes a number of spring assemblies <NUM> and a number of spring seats <NUM>. A spring assembly <NUM> includes a number of springs <NUM> associated with each spring seat <NUM>. In one embodiment, each spring assembly <NUM> includes a single, linear spring rate compression spring <NUM>. In this embodiment, the mechanical bias assembly <NUM> is structured to, and does, apply a bias at a generally linear rate during the compression of the spring assemblies <NUM>.

In another exemplary embodiment, each spring assembly <NUM> includes a number of springs <NUM> that have a variable spring rate. (It is understood that reference number <NUM> represents a "spring" rather than a specific type of spring. ) The variable spring rate may be any of a progressive spring rate, a degressive spring rate, or a dual rate ( sometime identified as "progressive with knee") spring rate. As used herein, a "progressive spring rate" is a spring rate that increases in compression in a non-linear manner. As used herein, a "degressive spring rate" is a spring rate that decreases in compression in a non-linear manner. As used herein, a "dual rate" spring rate is a spring rate that increases at a first linear, or generally linear, spring rate until a selected compression is achieved and thereafter the spring rate increases at a different second linear, or generally linear, spring rate. That is, the first and second spring rates are substantially different from each other. Variable rate springs include, but are not limited to, cylindrical springs with a variable pitch rate, conical springs, and mini block springs.

In one exemplary embodiment, all spring assemblies <NUM> include substantially the same type of spring <NUM>. that is, for example, each spring assembly <NUM> includes a number of substantially similar linear spring rate compression springs <NUM>, or, a number of substantially similar dual rate compression springs <NUM>. In another exemplary embodiment, the spring assemblies <NUM> include different types of springs. For example, within the mechanical bias assembly <NUM>, one set of spring assemblies <NUM> include a number of substantially similar linear spring rate compression springs <NUM>, and, a second set includes a number of substantially similar dual rate compression springs <NUM>. In another exemplary embodiment, the variable rate spring assemblies <NUM> may include any of a number of dual rate springs, a plurality of springs with different compression rates, a number of progressive springs, a number of degressive springs, or a combination of any of these.

In an exemplary embodiment, compression springs <NUM> are disposed in the pressure chamber <NUM>. In this embodiment, at least a lower spring seat <NUM>' is a torus-shaped body <NUM> that corresponds to the pressure chamber <NUM> and the die center riser <NUM>. The lower spring seat <NUM>' is coupled, directly coupled, fixed, or unitary with, the upper side of the piston body <NUM>. The compression springs <NUM> are sized to be in compression when disposed in the pressure chamber <NUM>. In this configuration, the mechanical bias assembly <NUM> biases, i.e. operatively engages, the piston assembly <NUM> and therefore the upper pressure sleeve <NUM>. That is, the upper pressure sleeve <NUM> is biased to its first position.

In one exemplary embodiment, wherein the pressure concentrating forming surface <NUM>, described below, has an area of about <NUM><NUM> (<NUM> in<NUM>), the total bias pressure is a force of between about <NUM> kN (<NUM>,<NUM> lbfs) and 40kN (<NUM>,<NUM> lbfs), or about 35kN (<NUM>,<NUM> lbfs) acting on the pressure surface <NUM>, which has an area of between about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), between about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), or about <NUM><NUM> (<NUM> in<NUM>). Alternatively; in an embodiment wherein the pressure surface <NUM> has an area of about <NUM><NUM> (<NUM> in<NUM>), the pressure concentrating forming surface <NUM>, described below, has an area of between about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), between about <NUM><NUM> (<NUM> in<NUM>) to <NUM><NUM> (<NUM> in<NUM>), or about <NUM><NUM> (<NUM> in<NUM>). That is, the force/pressure is concentrated by a ratio of between about <NUM>:<NUM> to <NUM>:<NUM>, or between about <NUM>:<NUM> and <NUM>:<NUM>, or about <NUM>:<NUM>.

In an exemplary embodiment, a multiple station tooling assembly <NUM> is coupled to a press <NUM>, i.e. a one hundred ton press, as noted above. The multiple station tooling assembly <NUM> includes twenty-four stations or pockets <NUM>. In an embodiment wherein about 35kN (<NUM>,<NUM> lbfs) acts on each pressure surface <NUM>, i.e. on twenty-four pressure surfaces <NUM>, the total load is about <NUM>. 4kN (<NUM>,<NUM> lbfs) * <NUM> (pockets) = 850kN (<NUM>,<NUM> lbfs). About 850kN (<NUM>,<NUM> lbfs) is about 85Tonnes (<NUM> tons (<NUM>,<NUM> lbfs/<NUM>)). Thus, the upper tool assembly <NUM> with a hybrid bias generating assembly <NUM> in the configuration described herein solves the stated problem of being usable with existing presses and includes a force concentrating forming surface <NUM> that is structured to operate with existing 90Tonne (one hundred ton presses).

The total bias/force generated by the hybrid bias generating assembly <NUM> can also be expressed as a "total bias pressure. " As used herein, the "total bias pressure" means the total bias/pressure generated by the hybrid bias generating assembly <NUM>, and therefore the upper tool assembly <NUM>. Further, the mechanical bias assembly <NUM> creates a force which, as used herein, is considered to be evenly distributed over the pressure surface <NUM>. That is, the mechanical force may be treated as a pressure for purposes of calculating the forces and pressure acting on the components. In an exemplary embodiment, the mechanical bias assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure. Conversely, the pressure generating assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure. The force/pressure generated by the pressure generating device <NUM> acts upon the pressure surface <NUM>. In an exemplary embodiment, wherein the pressure surface <NUM> has an area of about <NUM> in<NUM>, the hybrid bias generating assembly <NUM> generates a pressure of between about <NUM> kPa (<NUM> psi) and about <NUM> kPa (<NUM> psi), or about 5314kPa (<NUM> psi). Further, in an exemplary embodiment wherein the mechanical bias assembly <NUM> generates about <NUM>%, of the total bias pressure and the pressure generating assembly <NUM> generates about <NUM>%, of the total bias pressure, the mechanical bias assembly <NUM> generates a pressure between about 3487kPa (<NUM> psi) and about 4484kPa (<NUM> psi), or about <NUM> kPa (<NUM> psi), and, the pressure generating assembly <NUM> generates a pressure between about 1162kPa (<NUM> psi) and about 1495kPa (<NUM> psi), or about 1329kPa (<NUM> psi). Further, the pressure generating assembly <NUM> is structured to pressurize the pressure chamber <NUM> at a generally constant pressure.

In an alternate exemplary embodiment, the hybrid bias generating assembly <NUM> is structured to have substantially all, or all, of the total bias pressure generated by the mechanical bias assembly <NUM> with the pressure generating assembly <NUM> generating a generally constant, but generally minimal pressure. That is, in this embodiment, the mechanical bias assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure. Conversely, the pressure generating assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure. Further, the pressure generating assembly <NUM> is structured to pressurize the pressure chamber <NUM> at a generally constant pressure. In this embodiment, the hybrid bias generating assembly <NUM> is an active hybrid bias generating assembly <NUM>.

Further, in this embodiment, the hybrid bias generating assembly <NUM> is structured to alter the ratio of force generated by the mechanical bias assembly <NUM> and the pressure generating assembly <NUM>. That is, for example, during an initial clamping operation, the total bias pressure is substantially generated by the mechanical bias assembly <NUM>, i.e. the mechanical bias assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure, and, the pressure generating assembly <NUM> generates between about <NUM>%-<NUM>%, or about <NUM>%, of the total bias pressure. After the initial clamping operation, i.e. during a secondary clamping operation, the total bias pressure generated by the mechanical bias assembly <NUM> is reduced to be greater than, or equal to, <NUM>% of the total bias pressure while the pressure generating assembly <NUM> generates up to <NUM>%, of the total bias pressure.

In an alternative embodiment, the hybrid bias generating assembly <NUM> is a selectable hybrid bias generating assembly <NUM> wherein the user selects the source that generates the pressure, i.e. either the mechanical bias assembly <NUM> or the pressure generating assembly <NUM>. In this embodiment, the mechanical bias assembly <NUM> generates between about <NUM>%-<NUM>%, or substantially all of the total bias pressure. Conversely, the pressure generating assembly <NUM> generates between about <NUM>%-<NUM>%, or a negligible percentage of the total bias pressure. That is, for example, the pressure generating assembly <NUM> generates a negligible percentage of the total bias pressure while generating enough pressure to bias elements of the upper tool assembly <NUM> downwardly during the upstroke. As before, the pressure generating assembly <NUM> is, in an exemplary embodiment, structured to pressurize the pressure chamber <NUM> at a generally constant pressure.

In another embodiment, the hybrid bias generating assembly <NUM> is again a selectable hybrid bias generating assembly <NUM> wherein the user selects the source that generates the pressure, i.e. either the mechanical bias assembly <NUM> or the pressure generating assembly <NUM>. In this embodiment, however, the pressure generating assembly <NUM> generates between about <NUM>%-<NUM>%, or substantially all of the total bias pressure. Conversely, the mechanical bias assembly <NUM> generates between about <NUM>%-<NUM>%, or a negligible percentage of the total bias pressure. That is, for example, the mechanical bias assembly <NUM> generates a negligible percentage of the total bias pressure while generating enough pressure to bias elements of the upper tool assembly <NUM> downwardly during the upstroke. As before, the pressure generating assembly <NUM> is, in an exemplary embodiment, structured to pressurize the pressure chamber <NUM> at a generally constant pressure.

In this embodiment, the pressure generating assembly <NUM> is structured to apply a variable pressure. That is, the pressure generating assembly <NUM> includes a pressure control assembly <NUM> (shown schematically) that is structured to vary the pressure within the pressure chamber <NUM>. The pressure control assembly <NUM> in an exemplary embodiment, includes a number of pressure sensors (not shown) in the pressure chamber <NUM> as well as a position sensor (not shown) structured to determine the position of the piston assembly <NUM>. The pressure control assembly <NUM> is structured to alter the pressure within the pressure chamber <NUM> according to a pressure profile. That is, the pressure control assembly <NUM> is structured to increase or decrease the pressure within the pressure chamber <NUM> depending upon the position of the piston assembly <NUM>. In an exemplary embodiment, the pressure control assembly <NUM> includes a programmable logic circuit (PLC)(not shown) and a number of electronic pressure regulators. The sensors and electronic pressure regulators are coupled to, and in electronic communication with, the PLC. The PLC further includes instructions for operating the electronic pressure regulators as well as data representing the pressure profile.

In an exemplary embodiment, the hybrid bias generating assembly <NUM> is structured to be switchable between an active hybrid bias generating assembly <NUM> or a selectable hybrid bias generating assembly <NUM>, or switchable between different configurations of either an active hybrid bias generating assembly <NUM> or a selectable hybrid bias generating assembly <NUM>, by virtue of removable springs <NUM>. That is, the springs <NUM> are removably coupled to the spring seats <NUM> within the pressure chamber <NUM>.

It is noted that, in another embodiment, the upper tool assembly <NUM> does not include a hybrid bias generating assembly <NUM>, but rather one of a mechanical bias assembly <NUM> or a pressure generating assembly <NUM> wherein the selected assembly provides <NUM>% of the total bias pressure. The mechanical bias assembly <NUM> or the pressure generating assembly <NUM> is coupled to a "pressure concentrating forming surface" <NUM> as discussed below. That is, the mechanical bias assembly <NUM> or the pressure generating assembly <NUM> is coupled to the other elements described herein.

As noted above, the upper pressure sleeve forming surface <NUM> is a pressure concentrating forming surface <NUM>. As used herein, a "pressure concentrating forming surface" <NUM> is a forming surface that engages a reduced area of the blank <NUM> relative to prior art forming surfaces. That is, prior art forming surfaces clamped the blank <NUM> disposed over the die core ring upper end's <NUM> rounded inner surface <NUM>, generally horizontal surface <NUM> and, in some configurations, the rounded outer surface <NUM>. As used herein, a "pressure concentrating forming surface" <NUM> is a forming surface that engages a limited portion of the surfaces of die core ring upper end <NUM>, or a limited portion of a crown <NUM> disposed between the pressure concentrating forming surface <NUM> and the die core ring upper end <NUM>. That is, a surface that does not "clamp" the blank cannot be part of the "pressure concentrating forming surface" <NUM>. The limited area, in one exemplary embodiment wherein the blank is generally circular, is a radially contiguous annular reduced clamp area. As used herein, a "reduced clamp area" is a radially contiguous annular area extending over a portion of the die core ring upper end's <NUM> generally horizontal surface <NUM>, but does not extend over the die core ring upper end's <NUM> rounded inner surface <NUM>. Further, as used herein, a "diminished clamp area" is a radially contiguous annular area extending over about <NUM>-<NUM>% of the die core ring upper end's <NUM> generally horizontal surface <NUM>, but does not extend over the die core ring upper end's <NUM> rounded inner surface <NUM>. That is, in the known art, the forming surface was generally planar and the entire surface, i.e. <NUM>%, engaged the die core ring upper end <NUM> and acted as a clamp area, whereas the presently disclosed force concentrating forming surface <NUM> includes a reduced clamp area.

In another exemplary embodiment, shown in <FIG>, the pressure concentrating forming surface <NUM> includes a plurality of "landings" <NUM>. As used herein, a "landing" is a limited area of the upper pressure sleeve forming surface <NUM>. In an exemplary embodiment, the pressure concentrating forming surface plurality of landings <NUM> includes between two and five substantially concentric landings 610A, 610B, 610C, 610D, 610E. That is, in an exemplary embodiment, the lower end of the upper pressure sleeve <NUM> includes an annular, i.e. generally circular, forming surface <NUM>. The plurality of landings <NUM> are concentric portions of the annular forming surface <NUM> which clamp the blank <NUM>. That is, only the landings <NUM> engage the blank <NUM>. The areas between the landings <NUM> are upwardly offset relative to the landings <NUM> so that these areas do not engage the blank <NUM>. Stated alternately, in an exemplary embodiment, there are concentric grooves <NUM> between the landings <NUM>.

As shown in <FIG>, the upper pressure sleeve forming surface <NUM> has a cross-sectional area that is much smaller than the cross-sectional area of the piston assembly <NUM> and/or the lower spring seat <NUM>'. In this configuration, the pressure/area applied to the blank <NUM> by the upper pressure sleeve forming surface <NUM> is greater than the pressure/area acting on the piston assembly <NUM> and/or the lower spring seat <NUM>'. That is, while the bias/force remains constant, the area upon which the bias/force acts is greater at the piston assembly <NUM> and/or the lower spring seat <NUM>' compared to the area at the upper pressure sleeve forming surface <NUM>. Thus, as the area at the upper pressure sleeve forming surface <NUM> is smaller, the pressure per unit of area is greater.

The increase in pressure per a unit of area is greater for a pressure concentrating forming surface <NUM>. That is, the area of a pressure concentrating forming surface <NUM>, as defined herein, is even smaller than the area upper pressure sleeve forming surface <NUM>. In an exemplary embodiment, using a pressure concentrating forming surface <NUM>, the ratio of the total bias pressure to the clamping pressure is between about <NUM>:<NUM> to <NUM>:<NUM> or between about <NUM>:<NUM> and <NUM>:<NUM>, or about <NUM>:<NUM>.

In this configuration, the clamping pressure is, in an exemplary embodiment, about at the elastic limit of the material being deformed. Moreover, in an exemplary embodiment, the material being deformed has a "thinning limit. " That is, as used herein, a "thinning limit" is the elastic limit of the material while under compression. That is, a material under compression may be placed under tension that exceeds the elastic limit of the material without tearing the material. Thus, as used herein, the "thinning limit" is pressure that allows the material to thin by about <NUM>% without tearing. The exemplary measurements above, e.g. the area of pressure surface <NUM>, are for a tooling assembly <NUM> working on aluminum that is initially about <NUM> (<NUM> inch thick). The pressure concentrating forming surface <NUM> is structured to generate a clamping pressure that is about at the thinning limit of aluminum and to thin the aluminum so that the thickness of the material in the chuck wall <NUM> may be reduced to a thickness of about <NUM> (. <NUM> inch).

Accordingly, as shown in <FIG>, use of the tooling assembly 200A described above includes introducing <NUM> material between tooling assembly 200A, generating <NUM> a total bias force within the tooling assembly 200A, clamping <NUM> the material between an upper tool assembly <NUM> and a lower tool assembly <NUM>, forming <NUM> the material to include a center panel, a circumferential chuck wall, an annular countersink between the center panel and the circumferential chuck wall, and a curl extending radially outwardly from the chuck wall, and selectively stretching <NUM> at least one predetermined portion of the shell relative to at least one other portion of the shell to provide a corresponding thinned portion of the shell.

It is noted that the method and assemblies for thinning a shell disclosed herein may also be used to thin the metal thickness on a can body, a can end and/or dome as well as on a cup, i.e. a precursor construct for a can body.

Claim 1:
Tooling (200A) for forming a shell (<NUM>), the tooling (200A) comprising:
an upper tool assembly (<NUM>) including an upper pressure sleeve (<NUM>);
the upper pressure sleeve (<NUM>) including a lower end (<NUM>);
a lower tool assembly (<NUM>) including a die core ring (<NUM>);
the die core ring (<NUM>) including an upper end (<NUM>), the die core ring upper end (<NUM>) disposed in opposition to the upper pressure sleeve lower end (<NUM>), and the die core ring upper end (<NUM>) including an inner, tapered surface (<NUM>), a rounded inner surface (<NUM>), a generally horizontal surface (<NUM>) and a rounded outer surface (<NUM>);
the lower tool assembly (<NUM>) cooperating with the upper tool assembly (<NUM>) to form material disposed therebetween to include a center panel (<NUM>), a circumferential chuck wall (<NUM>), an annular countersink (<NUM>) between the center panel (<NUM>) and the circumferential chuck wall (<NUM>), and a curl (<NUM>) extending radially outwardly from the chuck wall (<NUM>); and
wherein the upper tool assembly (<NUM>) and the lower tool assembly (<NUM>) move between a separated, first position, wherein the upper tool assembly (<NUM>) is spaced from the lower tool assembly (<NUM>), and a forming position, wherein the upper tool assembly (<NUM>) is immediately adjacent the lower tool assembly (<NUM>) to selectively stretch the material of at least one predetermined portion of the shell (<NUM>) relative to at least one other portion of the shell (<NUM>), thereby providing a corresponding thinned portion,
charaterised in that
the lower end (<NUM>) defines a pressure concentrating forming surface (<NUM>) that engages said material when the upper tool assembly (<NUM>) and the lower tool assembly (<NUM>) are in the forming position, the pressure concentrating forming surface (<NUM>) is disposed in opposition to a portion of the die core ring generally horizontal surface (<NUM>) but does not extend over the die core ring upper end's (<NUM>) rounded inner surface (<NUM>).