Process and apparatus for forming an outwardly curled lip on cylindrical container body

The invention provides a process and apparatus for forming an outwardly rolled lip on a cylindrical container body. The apparatus of the invention includes a mandrel having a cylindrical shaped portion and a lip forming annular cavity positioned coaxially with, and axially spaced from the cylindrical portion of the mandrel. The annular cavity has a generally semi-circular cross-section including an open mouth and a closed bottom extending outwardly of the mandrel. The mandrel additionally includes a radially tapered portion between the cylindrical portion and the lip forming die. The radially tapered portion tapers radially outwardly in the direction towards the lip forming die. An axial forcing means forces a cylindrical container body axially along the mandrel towards the lip forming die to thereby stretch the open end before the end is forced into the cavity and rolled outwardly.

FIELD OF THE INVENTION 
The invention is directed to a process and apparatus for forming an 
outwardly curled lip, i.e., rim, on a cylindrical container body. More 
specifically, the invention is directed to a process and apparatus for 
forming an outwardly curled or rolled lip on a cylindrical container body 
formed of a deformable material such as single or multiple layers of 
paperboard material. 
BACKGROUND OF THE INVENTION 
Non-metallic containers have achieved widespread commercial acceptance. 
These containers include a body made from plastic, paperboard, or a 
layered structure, such as one or more layers of paperboard having 
interior and/or exterior polymeric film or foil layers. Typically these 
container bodies are easier to manufacture, are less expensive, and/or are 
more environmentally acceptable than prior metal containers. 
In cylindrical form, non-metallic containers include a separate closure 
member at one or both ends of the cylinder. In some instances, the closure 
member may be a metallic closure member which is joined to the container 
body by outwardly rolling a portion of the lip of the container into a 
metallic flange of the metal closure, which is then crimped into the 
container body structure. Alternatively a peelable lidding member can be 
attached directly to a container body by means of a thermal seal formed 
between an integral lip on the container body and the lidding member. 
For plastic container bodies an integral top flange or lip can readily be 
formed during the molding process. However, for paperboard container 
bodies the lip-forming procedure is typically accomplished in a step 
separate from formation of the body, per se. 
For relatively thin walled container bodies, such as convolutely wound, 
frustoconically shaped cup bodies or cup bodies formed of thin walled 
thermoplastic materials, it has been proposed to form a lip on the upper 
end employing an apparatus including a splined surface support member as 
disclosed in U.S. Pat. No. 4,680,016 to Lynch. The frustoconical container 
body is forced onto the frustoconical splined support and the open end is 
then forced axially into a semicircular annular groove which initially 
forms an outwardly folded rim. Thereafter, a tucking finger, mounted at a 
rimming station, rolls the outward fold into a rolled lip as the mandrel 
supporting the container body is rotated. 
For relatively thick walled paperboard container bodies, for example, 
having a wall thickness greater than about 0.015 in., e.g. from 0.020 to 
0.055 inch, rolled lips are more difficult to form. Conventionally, such 
rolled lips have been formed employing a metal can flanger of the type 
used to flange a metal can. This flanging apparatus has been used because 
of the high wall strength of thick walled paperboard container bodies. 
High wall strength is particularly apparent in spirally wound bodies 
formed of multiple layers of paperboard with and without inner and/or 
outer layers of film and/or foil materials. In addition to high wall 
strength, these spirally wound bodies have a true cylindrical shape and 
thus the walls of the open end are not flared outwardly adding to 
difficulty in forming a rolled lip. 
The separate operation to form a rolled lip on relatively thick walled 
container bodies employing a separate flanging apparatus is both time 
consuming and requires added material handling procedures for passing 
partially formed container bodies to and from the flanging apparatus. 
Moreover, the use of the conventional flanging apparatus is a relatively 
slow process and the flanging apparatus is expensive. 
SUMMARY OF THE INVENTION 
The invention provides a simple and cost effective process and apparatus 
for forming a rolled or curled lip on a cylindrical container body. The 
process and apparatus of the invention can be used with thick walled 
paperboard, plastic, and composite layer body materials having wall 
thicknesses up to and exceeding 0.055 inches. The rolled lip forming 
process and apparatus of the invention can be readily incorporated into 
the conventional container body manufacturing process and apparatus so 
that a separate lip forming procedure using a separate apparatus is not 
required. 
The apparatus of the invention for forming a rolled lip on a cylindrical 
container body includes a mandrel having a first cylindrically shaped 
portion for supporting a portion of the interior of a deformable 
cylindrical container body. A lip forming die having an annular cavity is 
positioned coaxially with, and is axially spaced from the cylindrical 
portion of the mandrel. The annular cavity has a generally semicircular 
cross-section including an open mouth and a closed bottom extending 
outwardly of the mandrel and is positioned with the open mouth oriented 
generally transverse to the axis to the mandrel and in a direction facing 
the cylindrically shaped portion of the mandrel. The mandrel additionally 
includes a radially tapered portion between the cylindrical portion of the 
mandrel and the lip forming die. The radially tapered portion of the 
mandrel tapers radially outwardly in the direction from the cylindrical 
portion of the mandrel towards the lip forming die. An axial forcing means 
forces the cylindrical container body axially along the mandrel for a 
sufficient distance to force one end of the container body along the 
outwardly tapering section of the mandrel and into the annular die cavity. 
Advantageously, the axially outwardly tapering portion of the mandrel is 
tapered in an amount of up to 20.degree., and preferably is tapered in an 
amount of from about 1.degree. to about 10.degree.. 
In operation, a container body having an open end and about the same inside 
diameter has the outside diameter of the cylindrical portion of the 
mandrel, is placed onto the mandrel with the open end facing the lip 
forming die. The forcing member is thereafter engaged with the other end 
of the container body which can be either open or closed, to force the 
container body axially along the stationary mandrel in the direction 
towards the lip forming die. As the open end of the container body is 
forced over the outwardly radial tapering portion of the mandrel, the end 
portion of the container body is outwardly stretched. Thereafter, the 
stretched end of the container body is forced into the annular lip forming 
cavity. Continued axial pressure on the container body causes the end face 
of the container body to follow the semi-circular wall of the cavity and 
to roll outwardly, thereby forming the rolled lip on the container body. 
Although not wishing to be bound by theory, it is believed that the 
outwardly radial tapering portion of the mandrel performs both a 
stretching and a deburring operation on the leading inside corner of the 
container body. In this regard, spirally wound container bodies are formed 
as a continuous tube on a stationary mandrel and container bodies are cut 
from the continuous tube employing a moving saw or blade which cuts 
radially through the bodywall of the continuous tube. This, in turn, 
results in an interior cylindrical burr on the end face of the tube. It is 
believed that this cylindrical burr interferes with the rolled lip forming 
process. In the present invention, the stretching operation is believed to 
eliminate or minimize the burr and/or to convert the burr into a form 
which more readily can be outwardly rolled as the end face of the 
cylindrical tube is forced into the lip forming annular die. 
In one preferred embodiment of the invention, a turret-type forming 
apparatus which includes a plurality of radially oriented forming 
mandrels, incorporates the apparatus of the invention. Typically, the 
turret-type forming apparatus is also employed to form and attach a bottom 
closure on the end of the container body which is opposite the rolled lip 
end. By incorporating the apparatus of the invention into the turret-type 
forming apparatus, the lip forming operation can be conducted at any of 
various stations in the multi-station forming process. Preferably, the lip 
forming operation is accomplished in conjunction with an initial step of 
mounting a container body onto a mandrel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 illustrates an exploded view of one preferred container which 
employs container bodies made according to the present invention. The 
container includes a spirally wound cylindrical bodywall 10, a separate 
bottom closure member 12, a peelable lidding member 14, and a deformable 
plastic lidding member 16 which can be used to reseal the package after 
removal of the peelable lidding member 14. The container body 10 is 
typically a thick walled composite or paperboard laminate having a 
thickness greater than about 0.020 inch. In the form illustrated in FIG. 
1, the container bodywall 10 typically is formed from one or more 
paperboard layers and also includes an interior film or film/foil liner at 
location 18 shown in FIG. 2. The interior liner generally includes a 
polymeric coating on the interior-most surface thereof for thermal bonding 
to the interior of the peelable lidding member 14. 
A rolled lip 20 is best seen in FIG. 2. The rolled lip provides a surface 
at location 22 for bonding to the peelable lidding member 14, and 
additionally provides an exterior flange for gripping by the flanged edge 
24 of flexible closure member 16. As also best seen in FIG. 2, the bottom 
closure member 12 is trapped at a lower portion of the container body 
between an outer wall of the container body and an inwardly folded crimped 
edge 26. 
The container body wall 10 is preferably formed by a conventional spiral 
winding process as will be well known to the skilled artisan. In general, 
such process involves wrapping one or more layers of continuous strip 
material around a stationary mandrel. Prior to winding of the layers, they 
are coated with adhesive materials to ensure formation of a strong bond 
within the bodywall. Generally, for container type structures, the 
interior-most layer is a film or film/foil laminate. To this layer is 
bonded one or more paperboard layers. The outer layer typically is a thin 
glossy paperboard layer and/or a film layer. The total bodywall thickness 
is normally between about 0.015 and about 0.070 inch, preferably between 
about 0.020 and about 0.055 inch. The continuous paperboard and film or 
foil strips are wound around the mandrel to thereby form a continuous 
cylindrical tube which is cut into segments of the desired length at the 
discharge end of the mandrel. 
FIG. 3 illustrates in top view, a turret-type forming station which 
receives pre-cut cylindrical container bodies and which then performs 
various operations on the bodies for converting the bodies into 
containers. In accordance with the present invention, the turret apparatus 
shown in FIG. 3 is modified to include a lip forming apparatus. 
In the form illustrated in FIG. 3, the apparatus includes a plurality of 
identical mandrels 30 which are rotated via a turret member 32 to move 
container bodies to various stations along the apparatus. As illustrated 
in FIG. 3, stations 1 and 2 receive container bodies 10 from a container 
body conveying apparatus 34. The cylindrical container bodies 10 are 
forced partially onto the empty mandrels 30 via the conveying and loading 
apparatus 34. A loaded mandrel from position 2 is then indexed to position 
3. In a conventional operation, the container body is forced or tamped 
fully onto the mandrel at position 3 and thereafter the turret is indexed 
to position 4. Positions 4, 5, 6, 7 and 8 are conventionally used to 
insert a bottom closure member into the container body and to seal same 
into the container body. Typically, at position 4 a heating apparatus 36 
contacts a portion of the interior periphery of the tube for preheating of 
same. The preheated container body is indexed to position 5 wherein a 
closure member supplied via conveying system 38 is inserted into the open 
bottom end of the container body. At position 6, the container bottom 
closure member is preheated by heating apparatus 40. At position 7 the 
lower portion of the container bodywall is folded inwardly by a folding 
apparatus 42 and bonded to the closure. At position 8, a finishing 
operation is conducted on the inwardly folded bottom of the container body 
by a finishing apparatus 44. At position 9, forced air from the interior 
of the mandrel 30 ejects the container body from the mandrel. 
FIG. 4 illustrates the lip forming apparatus of the invention as 
incorporated into station 3 of the turret forming apparatus shown in FIG. 
3. The lip forming apparatus includes a mandrel body 30, a lip forming 
annular die 50 and an axial forcing member 52 for forcing the container 
bodies 10 radially inwardly along the mandrel body 30. The axial forcing 
member 52 is carried by a moveable support 54 and is moved inwardly and 
outwardly by a motor means, not shown, which is attached to the support 54 
via rod 56. 
The apparatus of FIG. 4 is best seen in FIG. 5. With reference to FIG. 5, 
it can be seen that the mandrel 30 is formed from a mandrel body support 
60, which supports a plurality of exterior sleeves 62, 64 and 66. Sleeve 
62 has a true cylindrical exterior shape. Sleeve 64 is a frustoconical 
shaped sleeve which tapers radially and is best seen in FIGS. 6, 7 and 8, 
discussed in detail below. Sleeve 66 includes an annular lip forming die 
for forming folded rim 20 on container body 10. The outer surfaces of 
sleeves 62, 64 and 66 provide a substantially continuous and substantially 
smooth exterior compound surface to allow the container body to slide 
smoothly axially along the mandrel. 
A moveable clamping member 68 is provided at the radially inward end of the 
mandrel body 30 and functions together with annular bottom member 70 for 
clamping the sleeve members 62, 64 and 66 to the exterior of the mandrel 
body member. The interior portion of the mandrel body includes an axially 
positioned bore 72 which receives pressurized air from an air inlet 73 and 
is used to eject container bodies from the mandrel at position 9 as 
discussed previously. 
A preferred forcing means for forcing the container body 10 along the 
mandrel 30 is seen also in FIG. 5. The forcing means includes a short 
exterior cylindrical sleeve portion 74 which is sized to contact a portion 
of the exterior circumferential surface of the container body 10 adjacent 
the end thereof. An interior cylindrical sleeve 76 has an exterior 
circumference sized to support a portion of the interior circumferential 
surface of the container body 10 adjacent the end thereof. The space 78 
formed between the exterior sleeve 74 and the interior sleeve 76 is of 
substantially the same thickness as the thickness of the body wall of the 
container body 10. In addition, at the lower end of the space 78 there is 
a bottom wall 80 which is sized and positioned to contact the bottom end 
face 82 of the container body 10. 
Together, sleeves 74, 76 and bottom wall 80 of the forcing means cooperate 
to engage and support the end face and exterior and interior peripheral 
surfaces of the container body during the axial forcing operation. This in 
turn prevents or minimizes deformation of the container body end during 
the forcing operation. Engagement of the axial forcing member 52 with the 
container body member 10 is illustrated in phantom in FIG. 5. As seen by 
the phantom illustration, the bottom periphery of the container body 10 is 
supported about a portion of its circumferential exterior adjacent its end 
face by exterior sleeve member 74 and about a portion of its 
circumferential interior adjacent the end face 82 by the interior support 
member 76. In addition, the bottom wall 80 of space 78 is in surface to 
surface contact with end face 82 of the container body member 10. 
As shown in phantom, the axial forcing member 52 moves axially inwardly to 
a position 88 wherein the end face 82 of the container body is engaged by 
the forcing member 52. Thereafter, the axial forcing member is moved 
axially toward the mandrel to a second position 90. This in turn, moves 
the container body 10 axially along the mandrel body thereby forming 
curled lip 20 on the upper edge of the container body. It will be 
recognized that the axial forcing means shown in FIG. 5 is a preferred 
embodiment of the invention and that other forcing means can be used in 
the present invention. Thus, flat, annular or differently configured 
forcing members which are designed and arranged to engage only the 
interior, exterior and/or the end face of the container body can also be 
advantageously used herein. 
Formation of the curled lip is best illustrated in FIGS. 6, 7 and 8. 
Referring to FIG. 6, it is seen that segment or sleeve 64 tapers outwardly 
on an angle, 92, which can be up to 20.degree., preferably is between 
0.5.degree. and 10.degree. and is more preferably between about 
0.5.degree. and about 5.degree., depending upon the length of the segment 
64 and upon the diameter of the container body 10. Preferably, the length 
and degree of taper for segment 64 are such that the container body 10 is 
stretched outwardly, i.e., increased in diameter, in amount of between 
about 0.010 and about 0.030 in. as the container body 10 is forced along 
segment 64. 
In general, the degree of taper and length of segment 64 will be at least 
sufficient to ensure an interference fit between the leading edge of 
container body and the exterior of the mandrel at the large diameter end 
of segment 64 adjacent the annular cavity 100. The interference fit or 
stretching is needed to even out the container body to ensure 
substantially equal radial pressure 360.degree. around the perimeter of 
the container body as contact with annular cavity 100 is initiated. 
Additionally, as indicated previously the tapered segment 64 also 
functions as a deburring tool for the leading edge of the container body. 
The degree of taper and length of the frustoconical segment 64 will thus 
vary depending on factors including the diameter and wall thickness of the 
container body. For example, the diameter of cylindrical segment 62 is 
typically chosen to be slightly less than the interior diameter of the 
container body to provide a good sliding fit of the container body on the 
cylindrical segment 62. Typically, a greater amount of clearance between 
the segment 62 and the container body is chosen for larger diameter 
container bodies. This in turn requires a somewhat increased degree of 
taper and/or length for the tapered segment 64 with larger diameter 
container bodies to ensure an interference fit at its larger end. Thus, 
the configuration of the segment 64 can be changed due to the fit between 
the container body and the segment 62 or to accommodate various other 
factors such as a change in the profile of annular cavity 100. 
Returning to FIG. 6, the container body is moved in the direction shown by 
arrow 94 along segment 64, and the leading end 96 of the container 
bodywall is stretched outwardly. In addition, any container body burrs 
which were formed on the leading inside bodywall corner 98 during a 
previous cutting operation are substantially removed as the container body 
wall is forced along the axially outwardly tapering segment 64. 
As also seen in FIG. 6, the annular lip forming cavity 100 includes a 
closed bottom portion 102 and an open mouth portion. The inside surface of 
the cavity is smooth to promote sliding of the container end along the 
contour thereof. The mouth of cavity 100 is oriented substantially 
transversely to the cylindrical mandrel body and faces generally in the 
direction of the cylindrical segment 62. For container bodies having a 
wall thickness of between about 0.020 and about 0.055 in., cavity 100 can 
have a radius 101 of between about 0.060 and about 0.095 in. For greater 
wall thicknesses, this radius can be increased. In addition the profile of 
cavity 100 can also be modified as will be apparent. 
FIGS. 7 and 8 illustrate entry of the leading end 96 of the container body 
into annular cavity 100. As shown in FIG. 7, as the leading edge 96 of the 
container body is moved along the inside surface of the cavity, it is 
gradually turned radially outwardly. As shown in FIG. 8, the continued 
axial movement of container body 10 forces the leading edge 96 of the 
container body along the interior surface of cavity 100 and forces the 
edge to roll outwardly until the edge contacts the outer surface of the 
container bodywall, thereby forming the rolled lip 20. Thus, it will be 
appreciated that the rolled lip formation is accomplished in a single step 
by axially forcing the container body along a cylindrical mandrel, and 
along an outwardly tapering section thereof and finally into a 
semi-circular cavity. No separate rimming or flanging operation is 
required in order to form the rolled lip. Moreover because the rolled lip 
is contacted only with the smooth surface of interior cavity 100, the 
likelihood of formation of any surface defects on the lip is minimal 
The invention as illustrated herein is susceptible to numerous and various 
modifications and changes as will be readily apparent to the skilled 
artisan. For example, in the mandrel illustrated in FIGS. 4 and 5, the 
exterior shape and the cavity forming member are formed by three separate 
sleeve segments, 62, 64 and 66 which cooperate to form a substantially 
smooth and continuous exterior surface. This allows sleeves of smaller or 
greater outside diameter to be attached to a single mandrel core body 60. 
In addition, sleeves of different lengths can be employed for use with 
longer or shorter container bodies. However, it will be apparent that a 
single mandrel having the desired outside shape can be employed without 
the necessity for added sleeve members where desired. Similarly, only a 
single sleeve may be used for attachment to a mandrel core body. In such 
event, sleeve segments 62, 64 and 66 can be fabricated as a single unit. 
Alternatively, fewer or lesser segments may be employed to prepare the 
exterior mandrel shape illustrated in FIG. 5. 
The mandrel shown in FIG. 5 includes various end face portions which are 
particularly useful for upstream apparatus to insert bottom closure 
members. It will be apparent that in the event a different mandrel system 
is used for inserting bottom closure members, a different mandrel end 
construction can be employed. Likewise, the central air supply bore 72 
shown in FIG. 5 is an optional feature. 
It will also be apparent that the apparatus of the invention can be 
employed in constructions other than the radial container forming 
apparatus shown in FIG. 3. Thus, a multiple station container forming 
apparatus wherein a plurality of mandrels are linearally arranged can also 
incorporate the apparatus of the invention. Still further, the apparatus 
of the invention can be employed as a stand-alone apparatus when container 
bottom closure members are integrally incorporated into a container body 
or are incorporated therein in a separate operation. 
The invention is particularly useful for paperboard spirally wound 
container bodies of relatively large wall thickness as has been described 
in detail previously. However, it will be apparent that the apparatus and 
process of the invention can also advantageously be used in connection 
with other deformable container bodies including bodies formed of plastic 
material and the like. Similarly, the apparatus is considered particularly 
advantageous for paperboard bodies formed by convolute winding processes 
and the like. 
The invention has been described in considerable detail with reference to 
its preferred embodiment. However, it will be apparent that numerous 
modifications and variations can be made within the spirit and teachings 
of the inventions as described in the foregoing detailed specification and 
defined in the appended claims.