JP3149945B2 - Method and apparatus for processing containers - Google Patents

Abstract

A drawn and ironed container (C) that includes a cylindrical side wall, a smoothly-tapered neck (134) with an open end and an integral bottom wall (137) at the opposite end has a plurality of inwardly-deformed panel segments (130) located in the side wall between adjacent arcuate segments (132) with the panel defining generally chordal bottom walls for the panel segments. The container is formed using a multi-station processing apparatus that consists of a plurality of identical stations (30) located around the periphery of a rotating turret (26). Each station includes a support mandrel (50), a container loading means (52, 53) and an impression mandrel (54), with the impression mandrel being pivoted into and out of pressure engagement with the support mandrel to deform the side wall of the container. The support mandrel has a cylindrical peripheral surface (102) that conforms to the inner diameter of the container side wall and has circumferentially-spaced, axially-extending pockets (104). The pockets have sharp opposite edges (108a) that cooperate with the impression mandrel to produce the panel segments in the side wall.

Description

Description: TECHNICAL FIELD The present invention relates generally to the construction of two-part containers, and more particularly to a method and apparatus for processing such containers to increase their strength and improve their appearance. .

BACKGROUND OF THE INVENTION Two-part cans are the most common type of metal container used in the beer and beverage industry and for aerosol and food packaging. The two-part container consists of a single body, including a side wall having an open end on one side and an integral end wall on the other end. The integral end wall is typically formed in a dome shape to increase the strength of the entire container. An annular portion is usually formed in a special shape between the central dome-shaped panel of the bottom wall and the side wall defining a reduced diameter support for the container, and its open end Provide a nesting feature for nesting with the edge of an adjacent container, which is spliced.

An exemplary bottom profile for a drawn and textured container that has achieved remarkable market success is disclosed in US Pat. No. 4,685,582. The container disclosed therein can also be used to enclose a second drawn panel or a flattened, open-ended container with a smaller diameter end at one end. As such, it includes an upper end portion with a reduced neck.

In most cases, containers used for beer and carbonated beverages are formed from flat aluminum disks to an outside diameter of 2-11 / 16 inches (called "211-containers"),
The diameter of the upper open end is 209- so that the smaller diameter end can be used in the finished package.
Neck (2-9 / 16 inch) or 207-1 / 2-neck, 206-
Some other smaller diameter, such as the neck, and 20
4--reduced to form a neck or smaller neck.

An important competing goal in the packaging industry is to reduce the total can weight as much as possible while meeting its needs and maintaining its strength and performance. For pressurized contents, such as soft drinks or beer, the wall at the integral bottom end of the container usually has a standard substrate of the same metal thickness as the original disc, and the side walls Through the drawing and surface smoothing process, it is reduced to a thickness close to 1/3 of the original metal disc thickness. Thus, in order to minimize the overall weight, the can top or end panels that make up the second part of the two-part can have a structural integrity of the container, its functionality, and an aesthetically pleasing appearance. The diameter is formed as small as possible while maintaining the diameter.

In the manufacture of this type of container, a sheet of storage material of a predetermined thickness is fed to a cup making press, where a disk is cut from the storage material and has a diameter significantly greater than the final diameter of the finished container. Transfer into a glass with

The preformed cup is then passed to a container former, commonly referred to as a "body maker," where the cup is placed at the end of a plurality of spaced surface leveling dies and punch passages. Aligned with a punch carried on a reciprocating ram that operates with a dome forming mechanism located at During the forming process, it initially works with the redraw assembly, where the shallow cup is re-drawn to a smaller diameter with an inside diameter approximately equal to the inside diameter of the finished container and a height greater than the height of the first cup. Squeezed.

Each cup then passes through a series of surface leveling dies having progressively smaller diameters, so that the thickness of the container sidewall is progressively reduced, while the height of the container is increased. I do. At the end of the stroke for punches or sticks, the end of the container forms a unitary end wall with a dome-shaped overhanging panel in the middle and a specially shaped peripheral annular support part Therefore, it is forcibly formed in a predetermined shape. The drawn and surfaced container is then cut into a selected height, coated and labeled, with a sloping neck with a small diameter at the open end Is formed.

In order to produce containers that are competitive in price and that can meet the stringent industry demands for processed content such as beer and carbonated beverages in particular, the assignee of the present invention provides A neck-forming operation using a mold was developed to progressively reduce the upper open end to a smooth, molded neck shape. This is done through multiple passes until the desired reduction for the edge, such as the 206 or 204 edge, is achieved. This process is disclosed in US Pat. No. 4,774,839, which is incorporated herein by reference. Containers of the type having a bottom profile as disclosed in U.S. Pat.No. 4,685,582 and a smooth, molded neck shape illustrated in the patents listed above are enhanced. It has excellent strength properties and enhances the overall aesthetic appearance.

To further enhance the overall appearance of the drawn, surfaced container consisting of two parts, the appearance of a flute as disclosed in U.S. Design Patent Nos. 283,011 and 290,688 is provided. It has also been proposed to deform the side wall of the container to create.

According to the present invention, formed from a minimum amount of storage material,
Moreover, only one drawn and surfaced container has been developed which can meet all the stringent requirements for containers suitable for use in the beer and beverage industry in particular.

In particular, the container of the present invention can be formed from a flat disc of storage material, aluminum that has leaked heat, preferably less than 0.0120 inches, 250 lb and 90 p, respectively.
Can meet the requirements of sieve minimum immersion and twisting.

Containers formed from a flat aluminum disc made of aluminum shall have a bottom wall with a thickness substantially equal to the thickness of the storage material and a thickness of the side wall which is of the order of 1/3 the thickness of the storage material. The bottom wall has a centrally inwardly domed panel connected to the side walls through a countersink having outer and inner, generally flat, substantially vertical walls.

The side wall of the container is a plurality of substantially circumferentially spaced, axially extending, inwardly deformed panel portions substantially co-axial with the remainder of the side wall. Alternatively, they are formed between arcuate portions and smoothly merge with the side walls adjacent the opposing ends of those panel portions. The panel portions are located within the boundary of the side wall between the junction of the countersink at the bottom and the junction of the inwardly inclined neck at the open end above the container.

According to one aspect of the invention, the panel portions are:
It is formed in the sidewall in one continuous step through a device including a turret mounted for fixed rotation on a support column. The turret has a plurality of identical deformation stations circumferentially spaced about its periphery. Each deformation station includes a support mandrel supported for rotation around a fixed shaft on the turret, and an axially aligned loading mechanism for loading the container on the support mandrel. have. Each station also has a movement for engaging or disengaging a pressure mandrel with the support mandrel to deform the container therebetween,
Mounted on the turret, adjacent to the support mandrel,
It has a built-in compressible mandrel.

According to another aspect of the invention, a pair of adjacent push rods are mounted on a common support shaft. The support axle is rotated on a fixed axle on the turret to simultaneously swing the two push axles in and out of pressure contact engagement with the support axle associated therewith.

The support mandrel has a plurality of circumferentially spaced pockets formed between adjacent raised areas. Each pocket extends inward from the outer wall and has opposing edges, generally defined by radial walls, terminating in a bottom wall defining a generally chordal portion between adjacent raised areas. I have. The opposing ends of the bottom wall of each pocket are smoothly sloped and merge with the perimeter of the support mandrel. This defines a smooth transition between the bottom wall of the pocket and the circumference of the mandrel.

Preferably, the pocket is positioned on the mandrel such that a panel portion is formed on the side wall of the container between the junction of the bottom wall and the angled neck at the opposite end of the side wall.

According to another aspect of the invention, the support mandrel and the pressing mandrel at each station are driven in a synchronized relationship. This defines a common velocity for the surface around each mandrel. The drive mechanism for the pressing mandrel is
It incorporates a friction drive to accommodate any necessary differences in ambient speed due to compression of the press mandrel during press contact with the support mandrel.

In the method of operating a device for deforming a container having excellent properties as described above, the container is sequentially fed from a source to a respective support or loading means at each of the stations on the turret, the It is cammed on the respective support mandrel by a suitable cam interposed between the support and the turret. Also, each pressing mandrel is swung through a suitable cam mechanism to create a pressurized contact engagement between the pressing mandrel and its associated support mandrel at each of the stations, while both mandrels are continuous through a common drive. Rotated.

A control slide is provided between the common drive and each pressing mandrel to accommodate compression of the pressing mandrel.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view with some parts broken and removed showing a processing apparatus constructed in accordance with the present invention.

 FIG. 2 is a side elevational view of the apparatus shown in FIG.

FIG. 3 is a side view of the apparatus taken along line 3-3 of FIG.

FIG. 4 is a partial plan view of a pair of pressing mandrels forming part of the apparatus of FIG.

FIG. 5 is a sectional view taken along line 5-5 in FIG.

FIG. 6 is a schematic top view of various stations of the apparatus shown in FIG. 1, showing the relationship of the pressing mandrel in relation to a pair of forming or supporting mandrels at one processing station.

FIG. 7 is a partial side view showing details of one of the processing stations as viewed along line 7-7 of FIG.

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7, including a portion of the can wall showing the joint movement of the pressing mandrel and the support mandrel.

FIG. 9 is a partial sectional view showing an apparatus used for reshaping the bottom wall of each container.

FIG. 10 is an enlarged partial sectional view similar to FIG.

FIG. 11 is a perspective view of the finished container after the neck forming and flange forming operations.

 FIG. 12 is a perspective view of a forming mandrel.

FIG. 13 is a sectional view taken along line 13-13 of FIG.

FIG. 14 is a sectional view taken along the line 14-14 in FIG.

DETAILED DESCRIPTION As the present invention can be embodied in many different forms, it is shown in the drawings wherein the present disclosure must be considered as exemplifications of the invention, and broad aspects of the invention are described. Preferred embodiments of the present invention are described in detail with the understanding that they are not intended to be limited to the illustrated embodiments.

FIG. 1 of the drawings discloses a container processing apparatus, generally designated by the reference numeral 20, consisting of a base (FIG. 2) having an upright central post or column 24 supporting a rotatable turret 26. The turret 26 is rotated around a central support means or column 24 through drive means 28 mounted on the base 22. Turret 26 has a plurality of substantially identical processing stations 30 mounted therearound. There are twelve stations, as shown in FIGS. 1 and 2, the number of which can easily be increased or decreased in connection with the manufacturing equipment.

The drawn and surfaced container, consisting of two conventional parts before neck and flange formation, is supplied by a feeding mechanism 32.
And is removed from the processing device through the discharge mechanism 34. The feed mechanism 32 includes a conventional star wheel 36, which has a plurality of peripheral pockets 38 for receiving containers from a continuously moving conveyor 40 for feeding to each of the processing stations 30. have. Preferably, the supply device 32 includes a guide rail 42, which, as will be described, picks up the container at each of the stations 30 so that the container is stationary.
Guide along 44.

Similarly, the discharge mechanism 34 includes a second star wheel 46, which is again machined from each of the stations 34, or vertically, for final supply to the continuously moving conveyor 40. It has pockets 48 for receiving grooved containers, where those containers are transported for further processing. The ejection mechanism 34 again has an arcuate guide plate 49, as shown in FIG. The processed container is withdrawn from the processing station 30 by the star wheel 46 and guided along the support plate 44 to the conveyor 40.

As shown in FIG. 1 and FIG.
Incorporates a support mandrel 50, a platform 52 mounted on a piston rod 53, and a push mandrel 54 (FIG. 2). A platform 52 is supported on a piston rod 53 which reciprocates vertically through an opening in the turret 26 through a cam mechanism of a known type (not shown). Can be The cam mechanism for moving platform 52 between the low and high positions could be of the type shown in U.S. Pat. No. 4,519,232, which is incorporated herein by reference.

In this way, the container C has a second platform.
While in the low position shown to the left of the extended platform in the figure, it is fed from the feed mechanism 32 to the platform 52, which is used to introduce or load containers onto the support mandrel 50. , Lifted by the cam drive mechanism. The loading mechanisms 52,53 can incorporate a vacuum source (not shown) to hold the container on the platform 52 before being received in the support mandrel 50.

The supporting mandrel 50 and the pressing mandrel 54 are continuously driven in a synchronized manner by a common drive mechanism (FIG. 1), the common drive mechanism being supported on the upper end of the stationary column 24 and having a plurality of It includes a central fixed drive gear 60 that meshes with the driven gear 62. The driven gears 62 are in driving engagement with gears 64 mounted on a support shaft 66 having a support mandrel 50 mounted on the lower end. In addition, each driven gear 64 has a support shaft that supports the pressing mandrel 54.
Meshes with a combined gear 70 mounted on 72. In this way, with proper selection of gear diameters and ratios, shafts 66 and 72 are driven at a common speed, and thus, for purposes described below, shafts 50 and 54 are driven at a common speed. I do.

According to one aspect of the present invention, each push mandrel is a mandrel 50,54 such that the turret 26 rotates and deforms the container C between the respective mandrels, as described below.
Are designed to engage or disengage with the support mandrel 50 while the is actively driven.

According to one aspect of the present invention, a pair of adjacent press mandrels 54 are supported on a common support mechanism and are simultaneously moved by a simplified cam drive mechanism, which drive mechanism comprises:
This will now be described with particular reference to FIGS. 4 and 5.

As shown therein, the support mechanism for the press mandrel 54 includes a support shaft 80 mounted on the turret 26 between adjacent pairs of processing stations 30. The support shaft 80 has a pair of arms 82 extending therefrom, which will be described later.
It is secured to the support shaft 80 in the desired angular orientation by a suitable set of screws (not shown).

Each of the arms 82 has a hollow support sleeve 84 fixed at its outer free end, which in turn supports a shaft 72 with a push mandrel 54 supported at its lower end. Preferably the shaft 72 is split and the upper part 72a with the gear 70 attached thereto and the lower part 7 supporting the mandrel 54
Including 2b. A suitable bearing 86 is interposed between the shaft 72 and the hollow support member 84 with a spacer sleeve 87 interposed therebetween, as shown in FIG.

Preferably, each push mandrel 54 includes a central rigid core 90, which supports a deformable or compressible outer member 92, preferably formed of polyurethane material or a suitable equivalent material. ing.

In one embodiment of the present invention, the push mandrel 54 absorbs a controlled differential speed or speed between the push mandrel and the support mandrel, rather than the common or uniform speed previously described. In addition, the lower support portion 72
attached to b. As shown in FIG. 5, the lower shaft portion 72b has a spacer collar 94 which is interposed between the bearing 86 and the rigid core 90,
The pressing mandrel is pressed against a collar 94 via a threaded fastener 96 received in a threaded opening 97 formed in the lower end of the lower support shaft 72b.
A spring washer 99 is interposed between the upper edge of the core 90 and the lower edge of the collar 94.

In this manner, the amount of frictional tension created between the hollow core 90 and the core 72b is adjusted by the appropriate torque applied to the fastener 86 compressing its spring washer 99 to produce the desired frictional tension. Can be precisely controlled by This provides a controlled differential speed between the positively geared support mandrel 52 and the push mandrel 54. Additional frictional force can be created by appropriate sizing of the shaft 72b relative to the core 90.

According to a principal aspect of the present invention, the supporting mandrel is supported by the pressure of the pressing mandrel such that the supporting mandrel produces a plurality of chordal portions which are deformed inwardly from the initial side wall of the container. It is formed and designed to be deformed inside. Thus, as shown in FIGS. 12, 13 and 14, the support mandrel 50 has a hollow circular shape having a circular peripheral surface 102 having a diameter substantially equal to the inner diameter of the container sidewall. Includes core 100. After the mandrel is finished to a cylindrical shape that matches the inside diameter of the container,
A plurality of circumferentially spaced pockets 104 extending in the axial direction are provided with support mandrel 5 by machining or the like.
0 is formed on the surface.

In particular, each pocket 104 is formed by machining a portion from the surface of the support mandrel 50 between adjacent pairs of raised areas 106. Growth area 106 is core 100
Has an outer surface 102a that matches the radius of the surface 102,
Flat bottom wall 109 that defines the chord surface between raised areas 106
Has a flat side wall 108 interconnected by. A flat sidewall 108 extending radially from the axis of the core 100 intersects the surface 102a and forms a sharp edge 108a. First
4 As clearly shown in FIG. 4, the shape of the cross section of each raised area is approximately square, and
It has a depth of inches and a width of approximately 0.030 inches. In this exemplary embodiment, the support mandrel has what is referred to as thirty equally spaced flutes formed in the side wall of the container, as more clearly shown in FIG. Designed to make cans or containers.

For such an embodiment, the adjacent elevation regions 10
The distance measured from center to center between 6 is about 12 ゜,
As such, the depth of the pocket 104 is about 0.030 inches. As shown in FIG. 13, the opposing ends of the pockets 104, especially the bottom wall 109, are flared at 109a and the outer surface 102 of the support mandrel 50 through a smooth transition.
Is fused with The function and operation of the pocket 104 will be described in detail in connection with the operation of the device described below.

As described more fully above, each push mandrel 54 cooperates with the support mandrel 50, with the "string" interposed between the side walls of the container between arcuate portions having a diameter equal to the diameter of the side wall of the container. Transform into multiple things called "parts". To this end, the pressing mandrel 54 is supported for movement to engage or disengage the can body on the center pivot mandrel 50 of the turret 26 surrounding the support column 24.

For this purpose (FIG. 1), the upper end of the column 24 has a stationary cam 110 attached to it, having a peripheral camming surface 112. Surrounding camming surface 112
Operates with a cam follower 114 attached to an arm 116 fixed to the upper end of the support shaft 80. In this manner, rotation of the turret 26 causes the cam follower to follow the cam surface 112 and the support shaft 80 around its support shaft.
Rocks. This means that the support arm 82
In conjunction with 54, the turret is rocked during or after each rotation cycle on or against its associated support mandrel 50 in or out of pressure engagement with the can body C.

The operation of this device is summarized here. The top-open, drawn and smoothed container is supplied by a supply mechanism 32.
From the conveyor 40 to the station 30.
The containers are received on a platform 52 and loaded onto the support mandrel 50 at each station while the turret 26 and the support mandrel 50 are rotating.

Pressing mandrel 54 actively driven by support mandrel
Is then brought into pressure contact with the cam by rocking the shaft 80 through the cam 112 and arm 116 to lock the can body and deform the container side wall. During this deformation, the fold line rises and the area or sharp edge 108 of the rib 106
a is formed in the container side wall and a chord portion is formed between their fold lines.

The amount of deformation of the chord portion is controlled by changing the engagement pressure between the pressing mandrel and the support bar. The engagement pressure is then controlled by the angular adjustment of the arm 82 on the shaft 80. Since the effective diameter of the compressible outer member 92 of the pressing mandrel 54 changes with the pressure between the mandrels, the friction drive between the shaft 72 and the mandrel 54, especially the spring washer 99 and the core 90, is combined with the peripheral speed of the supporting mandrel. Pressing on the mandrel will adjust the peripheral speed. Therefore, their speeds are synchronized.

As such, the deformed side wall 129 of the container takes the shape shown in FIG. 11, where a plurality of deformed portions 130 are defined between adjacent raised areas or arcuate portions 132. I have. The arcuate portion 132 has a peripheral arcuate shape that matches the arcuate shape of the container sidewall. Opposite edges of the deformed portion 130 are defined by fold lines 132a created by the sharp edges of the mandrel 50.

The container also includes a narrowed neck 134 and an outwardly directed flange 136 formed thereon by a neck forming process using a mold, as disclosed in the '839 patent previously discussed. , And the bottom profile referred to in the '582 patent as the ANC-1A bottom profile. Both patents are included here for reference.

The fluted, finished, drawn and surfaced container shown in FIG. 11 using the above apparatus is a conventional drawing, now used on a commercial scale. The processed and surfaced containers exhibited high physical properties never before experienced. In fact, containers incorporating fluted sidewalls exhibit significantly greater crush strength than the same non-fluted containers without fluted sidewalls. Moreover, the containers were formed from small thickness storage material or disks having the same cutting edge diameter as conventional disks.

In comparison of the crushing strengths, approximately 0.001 inch of aluminum storage material or disc with 0.0119 inch heat was used.
The same fluted container formed on a thin side wall having a thickness of 45 inches, the fluted side wall (round)
Which showed the following crushing properties:

The above data clearly show that the fluted container exhibited a very uniform crush strength of an average of 336 pounds, well above the required minimum of 250 pounds. Same,
In contrast to a non-fluted round-sided container that collapses at the bottom of the body, a fluted container swells just above the junction between the side wall and the bottom profile and may not collapse. Also decided. Although not fully examined,
The flared end of the chord portion 130 adjacent the junction with the integral bottom wall appears to increase the crushing strength for the container.

 These containers were formed with the following parameters.

The same container was subjected to a single can drop test after being filled with a commercially available soft drink beverage product. The single can bottom drop test is performed to evaluate the resistance of the bottom wall to turning over the dome when the can is dropped against the wall of the integral bottom end. The test apparatus consisted of a four foot tube securely attached to a hard steel base, and the cans were dropped from various heights until the dome turned over.

Twenty-four fluted and non-fluted (checking) cans were subjected to a drop test, and the checking cans showed a "rocker" defect with a drop of about 29 inches. . On the other hand, the fluted cans did not experience any "rocker" defects at a maximum drop of 4 feet. A "rocker" defect occurs when the profiled bottom wall of the container turns to a point where it can no longer be stable when the container is placed on a flat surface. These containers were filled with Classic Coke® soft drink and dropped on a 150 lb “B” flute test plate at a temperature of 76 ° F.

The fluted and checked cans are Diet-Caffei
Filled with ne Free-Coke and dropped at 76 ° F on a 0.024 inch Mead chipboard jacket. The check container suffered a "rocker" defect with a drop of about 8 inches. On the other hand, the fluted container suffered a "rocker" defect at about a 23 inch drop.

Thus, in conclusion, the fluted container is
It has been established to have much improved crush resistance with the lowest variability from container to container. Also, fluted containers have much greater resistance to turning the dome. That is, they can better absorb hydrodynamic shock.

Although the parameters have not yet been thoroughly investigated, fluted containers also reduce the bending resistance of the filled container when the product is exposed to high temperatures during storage in hot weather. Improve. The fluted container also eliminates "gull wings". It can lead to crushed containers during filling and edge splicing operations. The "gull wing" defect is a slight imperfection in the side wall of the container, which creates a corrugation in the side wall during the container forming operation.

Another factor that seems very important is the length of the flute in the side wall and its relationship to the junction between the side wall and the angled neck and to the integral bottom wall. The flutes, i.e. the opposing ends of the chord panel sections, must be as close as possible to their joints and must not intersect them. It has been determined that a spacing of about 0.050 inches from the ends of the flutes measured from their junctions creates an ideal container. However, their dimensions can be easily varied without significantly departing from the spirit of the invention.

The above tests also show that the containers exhibit significantly greater resistance to internal pressure without causing any damage to the container. The flutes built into the side walls have the ability to absorb a significant amount of hydrodynamic shock when the containers are dropped during a standard drop test. The formation of internal pressure tends to return the chords between the raised areas of the side walls to the general arcuate shape of the side walls of the container, without causing any damage to the side walls of the container. Provides greater resistance to increased pressure. It is also determined that because of the flutes, its internal pressure can be greater without any significant effect on the walls of the dome-shaped end of the container, i.e., without a significant degree of container growth or dome inversion. Was.

Actual tests have shown that the metal thickness of the storage material of the disc to form a drawn, surfaced container of aluminum, without sacrificing any of the strength properties of the container, It has been shown that it can be reduced. For example, tests have shown that storage material can easily be reduced to a thickness of 0.0118 inches, perhaps well below that level, without sacrificing strength properties for the container.

Although the parameters have not yet been thoroughly investigated, we believe that the greater the length of the flute between the dome-shaped end and the small diameter neck, the better the performance characteristics can be expected. Have been. In this way, the arcuate ends of the pockets 130 formed in the side walls of the container merge with the side walls just inside the fold line that defines the boundaries of the side walls to the narrowed neck 134 and the bottom 137. It is expected that.

Additional testing was performed to determine the potential for reducing the thickness of the sidewalls in the container while maintaining the minimum performance characteristics for the fluted container.

These tests do not account for any rolling or damage to the dome or any dents in the neck area of the container, but actually measure the amount of abuse that the container sidewall can absorb before damage occurs to the sidewall. Made to decide.

Wrought and leveled aluminum container 0.01
Formed on a commercial D81 machine from a stock disc of 20 aluminum. These containers have a 206
Normal with 211 side wall diameter with neck and 413 height
It was a 12 ounce container. The container sidewalls were thinned to an average thickness of 0.0039 inches. Check containers were tested and compared to fluted containers consistent with the teachings of the present invention.

The containers produced the following results in crush strength in pounds.

These fluted containers also exhibited average elongation (container growth) at a peak load of about 0.04 inches. On the other hand, the check container showed an average elongation of 0.03 inches.

The dome depth for these vessels was below the acceptable minimum of 0.380 inches, ie, when the depth was about 0.363 inches, acceptable growth for internal pressure and the minimum acceptable bending pressure (psig) was achieved. Tested to determine. The following test results were recorded.

These vessels exhibited unacceptable growth due to worn tools and / or thermal stress. However, these test results show that fluting the sidewalls allows the sidewall thickness to be reduced without sacrificing performance characteristics such as crushing strength, container growth, or resistance to bending. To indicate that

According to another aspect of the present invention, a container formed in accordance with the teachings above and disclosed in FIG. 11 may be formed from its original shape as disclosed in the previously mentioned '582 patent. By reshaping the bottom end wall of the container, it has improved performance characteristics that are even better. Thus, as shown in FIGS. 9 and 10,
After the fluted container has been neck-formed, flanged, internally spray-coated and printed on the outside, the bottom profile, especially the area of the countersink or protruding edge of the bottom wall, is Can be reshaped by reforming the inner wall of the countersink to further improve bending resistance and reduce can growth. This special process will also allow the thickness of the storage metal to be reduced without any change in the diameter of the cutting edge of the initial disc.

In this way, as shown in FIG.
The finished, drawn, surfaced container shown is supported in a suitable jig 150 having an internal opening 152 corresponding to the diameter of the outer circumference of container C. The jig has a lower profile portion 154 that matches the countersink wall portion of the bottom wall of the container as originally formed in accordance with the method disclosed in the '582 patent.

A plug 156 is inserted into the upper end of the opening and held firmly on top of the container. Profile 1 around the bottom of the jig 150
54 has extensive contact with the bottom 137 of the container. Correction roller 1
60 is engaged with the outside of the dome-shaped end 162 of the container and is supported on a shaft 164 that is designed to be rotated along an arcuate path around the central shaft for container C. I have. The rollers have a substantially vertical, upper outer side having a generally arcuate upper portion 168 such that the inner wall 170 of the countersink is modified to a more vertical profile, while the dome 162 is stretched to a small extent. Has a peripheral shape 166 that defines a wall inclined toward. Outer wall 172 is maintained in its original shape. As an alternative, the outer wall could also be modified along with the inner wall.

This corrective action has been found to significantly improve bending resistance and reduce the amount of can growth, that is, the amount by which the bottom end wall is stretched when pressure is applied from inside the vessel.

Thus, in summary, containers made in accordance with the method and apparatus of the present invention have been found to have significantly higher column strength, i.e., resistance to crushing due to vertical loads applied to the side walls of the container, and from the inside. It has significantly less vessel growth when pressurized and has improved bending resistance. It has been found that containers constructed in accordance with the present invention can be made from storage flat disc material having a significantly smaller thickness.

Although particular embodiments have been shown and described, many modifications may be made without departing significantly from the spirit of the invention, and the scope of protection is only limited by the appended claims.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Patent Publication No. 1-50493 (JP, B2) US Patent 4578976 (US, A) West German Patent Application Publication 2039528 (DE, A1) (58) Fields searched (Int) .Cl. ⁷ , DB name) B21D 51 / 26,22 / 28

Claims (12)

(57) [Claims] An end portion integral with the side wall;
A method of modifying the bottom of a container, the end having a central dome-shaped portion and a countersink having an annular substantially longitudinally extending inner wall and an annular outer wall, the method comprising providing the container, Providing a roller, engaging the modifying roller with the inner wall, and rotating the modifying roller along the inner wall about an arcuate path to modify the inner wall. 2. The method of claim 1 wherein said inner wall is modified to a more vertical position. 3. The method of claim 1 wherein said modifying roller has a peripheral shape defining a generally vertical, upwardly and outwardly sloping wall having a generally arcuate portion. 4. The method of claim 1 including providing radial inward support for said container. 5. The method of claim 4, wherein providing radially inward support comprises supporting the container in a jig. 6. The method of claim 5, wherein said jig includes a bottom outer peripheral profile portion shaped substantially corresponding to said annular outer wall of said container. 7. The method of claim 1 wherein providing the container comprises providing a drawn and surfaced container body formed from a single metal plate. 8. A countersink having a side wall and an end integral with the side wall, the end having a central dome-shaped portion and an annular substantially longitudinally extending inner wall and an annular outer wall. An apparatus for modifying the bottom of a container, comprising: a correction roller movable from a radially inner position that does not contact the inner wall to a radially outer position that engages the inner wall. 9. The apparatus according to claim 8, wherein said support has a radially inward support.
Equipment. 10. The apparatus of claim 9 wherein said radially inward support comprises a jig. 11. The apparatus of claim 10, wherein said jig includes a bottom outer peripheral profile portion shaped substantially corresponding to said annular outer wall of said container. 12. The apparatus of claim 9 wherein said modifying roller has a peripheral shape defining a generally vertical, upwardly and outwardly sloping wall having a generally arcuate portion.