CA1071514A - Method and apparatus for fabricating thermoplastic tubes - Google Patents

Abstract

ABSTRACT OF DISCLOSURE

The method and apparatus for forming a sheet of thermo-plastic material into a cylindrical sleeve by wrapping the sheet around a cylindrical mandrel with the end portions of the sleeve overlapping, directing a stream of hot air from a duct onto the facing surfaces of the overlapping end portions such that the uppermost end portion is lifted and the hot air softens the facing end surfaces of the thermoplastic sheet, upon the end surfaces becoming softened diverting the hot air away from the end portions, and pressing together the softened end portions with a sealing bar extending longitudinal of the mandrel over the overlapping softened portion.

Description

~L~7~5~ :

Background Of The Invention It has long been recognized that drinking cups and other nestable containers with superior properties, especially for the retention of hot beverages such as coffee, can be formed from expanded thermoplastic materials, the most popular of which has proven to be expanded polystyrene. A very popular cup of this type is a one-piece cup which is molded directly from expandable polystyrene beads in a steam chest.
However, in forming cups in this manner, it has proven to be necessary, for purposes of imparting adequate strength, rigidity and liquid impermeability to the sidewall thereof, to construct such cups with a thick sidewall, at least in rela- ~:
tionship to the sidewall thickness of other types of insulated cups. As a consequence of this added sidewall thickness, it is not possible to obtain as small a stacking height, or spacing, .
between like cups in a nested stack thereof, with the result that such cups require considerably more storage space than a comparable quantity of other types of nestable insulating cups~
Another disadvantage of the so called steam chest molded cup is that, as an inherent consequence of its mode of manufacture, the external surface of its sidewall can only be decorated by post decorating or printing techniques which are slower and more expensive than the flexographic and other sheet printing techniques which may be used in decorating cups fabricated from pre-printed sheet~ As a result, the vast majority of such steam chest molded cups which appear in the market place do not contain a decorated or printed outer surface~
Another known type of insulated or expanded thermo-plastic drinking cup which has enjoyed some measure of commer-cial popularity is a two-piece cup such as that which is manu-factured and marketed by the assignee of this application under the trademark "X-Fome" and which corresponds to the cup h~
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~7~L5~4 described in U.S. Patent No. 3,46~,467 which is assigned to the assignee of this application. The sidewall of such cup may be formed by conventional cup fabricating techniques from a crescent-shaped blank of an expanded plastic material which, in turn, is cut from a pre-printed sheet or web of indefinite length thereof. By controlling the density of such sheet, it is possible to fabricate a cup with adequate strength, rigidity and liquid impermeability and which, nonetheless, has a considerably thinner sidewall than a steam chest molded cup for superior stacking or nesting properties in relationship thereto. Also, the ease with which the exterior of the side-wall of such cups can be provided with attractive decoration by pre-decorating the sheet from which the sidewall blanks are formed, has made it possible for a substantial portion of such cups to be decorated in a way which has proven to be quite popular in the trade. One of the drawbacks of such a cup is its costliness, at least insofar as material costs are concernedl in relationship to the steam chest molded cup, due in part to the scrap which is inherently formed when a cres-cent shaped sidewall blank is cut from a sheet or web of normalcharacter.
Yet another known t~pe-o~ insulated or expanded thermo-plastic drinking cup which has also enjoyed some measure of commercial popularity is a one-piece, seamless deep drawn cup which is manufactured and marketed by the assignee of this application and which corresponds to the cup described in U.S.
Patent No, 3,666,162, issued May 30, 1972 (J. R. Tiffin et al).
Such cups can, in somewhat higher densities than conventional steam chest molded cups, be formed to very close manufacturing tolerances and with very low stacking height, and because of these features, they have, in spite of somewhat more costliness than the steam chest molded cup and the two-piece cup described ~15~L~

above, and in spite of the fact that they can only be decorated after forming, gained a substantial measure of popularity in the coin-operated beverage vending machine market.
Summary of the Invention As can be seen from the foregoing discussion, each of known types of insulated cups referred to therein has cer-tain advantages which makes it well-suited for some uses, and certain limitations which makes it less well-suited than one of the other types for other uses. In accordance with the present invention, however, there is provided an insulating cup which combines a wide range of desirable properties, without offsetting limitations, and which is, therefore, well-suited for a wide range of applications for insulated cups.
The sidewall of such cup can be formed from rectangular blanks, and therefore without the scrap and inherent expense involved in the severing of crescent-shaped sidewall blanks from a parent sheet or web, and the sidewall of such a cup may be relatively inexpensively provided with attractive, high quality decorative material. Additionally, such cup may be provided with relatively good stacking or nesting characteris-tics to minimize the required storage space which is important to the carryout beverage industry, which is the bulk user of these types of cups. It is also possible with close manu-facturing tolerances, to provide the reliable denesting which is necessary in coin-operated vending machine utilization of cupsO Relatively inexpensive high quality cups according to the present invention may readily be formed on a high produc-tion basis in either a one-piece version or a two-piece version.
The sidewall of either such version is formed from a web of polystyrene or other thermoplastic polymeric sheet material which has a substantial degree of orientation or heat-shrinkability in the machine direction, by severing ~7~5~4 rectangular sidewall blanks from such web, preferably after printing or other decorative material is applied to the web by flexographic or similar printing technique in a repeat pattern in registration with the blanks to be cut therefrom, by forming a cylindrical sleeve from each such blank with the machine direction of the parent web extending circumferentially thereof, including the forming of a liquid tight lapped seam between the ends of the sleeve, as by-heat sealing, by placing the sleeve over a forming mandrel having an outer forming surface corresponding to the desired configuration of the inner surface of the sidewall of the nestable cup to be formed therefrom, by heating the sleeve while it is so positioned over the mandrel to cause it to heat shrink into conforming face-to-face contact with the forming surface of the mandrel, and by stripping the shrunken sleeve Erom the mandrel. A
separate bottom closure may be affixed to a sidewall formed in this manner either while the sleeve is still in position on the mandrel, or after it is removed, by any of several known cup-manufacturing techniques. Alternatively, a one-piece cup may be formed by starting with a sleeve which is highly orien-ted in the circumferential direction and which exceeds the height of the forming mandrel over which it is to be telescoped by a distance on the order of one-half of the smaller diameter of such mandrel, with the sleeve being so telescoped over the mandrel that the excess portion of the sleeve extends beyond the smaller end of the mandrel. When such a sleeve is exposed to heat, the excess portion thereof will shrink to form an annular planar portion extending inwardly across the smaller end of the mandrel and a relatively small diameter tubulation extending longitudinally from the interior of such planar portion. By the application of opposed compressive forces to such tubulation while it is at elevated temperature, it can ~7~S~

be caused to collapse and to fuse together to close the interior of the annular planar portion in a liquid-tight fashion.
The fabrication of either a two-piece cup or a one-piece cup according to the present invention is effective to provide a cup whose sidewall thickness increases from a lesser thickness at the location of greatest diameter -to a greater thickness at a location of lesser diameter. This is especially desirable in that it provides adequate thickness in the lower portion of the cup to protect the hand of a user from the temperature of a hot beverage therein, while keeping the wall thin at the top of the container so that the bead or rim which is normally formed therein need not be excessively thick. This highly advantageous result is accomplished as a direct function of the method of the present invention, since the heat shrink-able sleeve that forms the cup sidewall shrinks to a greater degree adjacent to the bottom of the cup to thereby provide the desired increased thickness at the lower portion of the cup. Also, the degree of taper in the sidewall can readily be increased in the lower thicker regions to offset the adverse effect of a thicker sidewall on the stacking or nesting characteristics of like cups of this type.
The apparatus for fabricating two-piece cups in accordance with the method of the present invention includes a continuously moving main conveyor carrying a plurality of spaced mandrels having an-external configuration corresponding to the internal contour of the cup. The main conveyor moves the mandrels along a closed path through a series of opera-tional subassemblies which function in timed sequenced inter-relationship to form the cup of the present invention.
The mandrels are preheated to an elevated tempera-ture at a first working station to facilitate shrinkage of sleeve blanks. Individual rectangular blanks are cut from a ~7~5~
continuous web of heat shrinkable thermoplastic material, formed into a cylindrical sleeve blank and telescoped on to the preheated mandrels. Bottom disc closures are simultaneously cut from two continuous webs of thermoplastic material, and serially delivered to the mandrels on which the sleeves have been positioned.
The mandrels then pass to a heat shrinking station, where the sleeves are heated, as by infra-red radiation, to shrink the sleeves to conform to the external contour of the mandrels and to produce inwardly extending portions at their lower ends that overlap the bottom closure discs. The discs are also, at least partially, formed to the bottom contour of the mandrels by the heat and by the provision of internal vacuum ports in the mandrels which cause the discs to conform to the mandrels bottom surface. The mandrels then pass to a bottom sealing station where the overlapping sleeve portions are fused to the bottom closure discs.
The cups are then removed from the main conveyor to a rimming conveyor and the mandrels commence a new cycle by passing through the preheat subassembly. The removed cups are carried by the rimming conveyor to a rimming mechanism which forms a rim at the lips of the cups and then to an ejection -station where the completed cups are removed for packaging.
With the process and apparatus of the present inven-tion, cups having exceptional insulating properties can be fabricated at a relatively low cost. Because the operation of the machine is continuous in nature, it is extremely smooth in operation, and achieves a much higher production rate than has been possible in the past with known apparatus for fabri-cation of nestable cups.
Accordingly, it is a feature of the present inven-tion to provide a novel method of fabricating the sidewall of ~7~L5~

of an insulated nestable cup or similar container.
It is also a feature of the present invention to provide a method and apparatus for thermally fabricating the sidewall of a nestable cup or similar container from a rectangular blank of thermoplastic material and without the need for wasting a portion of the material in such blank; and, more particularly, it is a feature of the present invention to provide a method and apparatus for thermally fabricating the sidewall of such a cup or container from a rectangular blank of an expanded thermoplastic material to impart good insulating properties to such sidewall.
Thus, in accordance of one aspect of the present teachings, a method is provided of forming a cylindrical sleeve from a sheet of thermoplastic material which comprises the steps of forming the sheet into a generally tubular shape around a cylindrical support with one end portion of the sheet overlapping the other end portion. The one end portion is pressed into gripping contact against the support transversely of the one end portion inwardly of its outer free ed~e. A separation is established between the sheet overlapping end portions by directing a stream of hot air from a duct towards the gripping contact into the space between the overloapping end portions while maintaining the sheet in a fixed relationship to the duct. Th~ flow of hot air is continued into a V-shaped pocket formed between the separated end portions to cause the thermoplastics material of the separated end portions to soften. The stream of air is diverted away from the end portions after they become softened and the softened material of the overlapping portions are pressed together to form a seam.
By a further aspect and embodiment of the ~ 7 ~

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present teachings an apparatus is provided for forming a cylindrical sleeve from a sheet of thermoplastics material.
The apparatus comprises a cylindrical mandrel which is supported for rotation about its longitudinal axis with means provided for rotating the mandrel and means on the mandrel for holding one end portion of the sheet in contact with the mandrel to cause the sheet longer than the circumference of the mandrel to be wrapped around the rotating mandrel with the other end portion of the sheet in an overlapping relationship to the one end portion. Means are provided for pressing the other sheet end portion into gripping engagement against the mandrel a short distance inwardly from its outer free edge. A duct is provided connected to a supply of hot air which has an outlet adjacent the mandrel and is positioned to direct the hot air flow from the outlet into a V-shaped pocket formed between the facing surfaces of the overlapped sheet end portions by the pressure of air flow which heat softens the overlapping end portions. A sealing bar is provided extending longitudin-ally of the mandrel and supported for movement between a position retracted from the sheet and an extended position in pressing engagement with the overlapping sheet end portions. Means are provided for diverting the hot air away from the overlapping sheet end portions after the material becomes softened with means provided for moving the sealing bar from the retracted position to its extended position after the hot air has been diverted away from the sheet overlapping end portions to sealingly press the end portions together.
More particularly, it is a feature of the present invention to provide methods and apparatus of producing one-11~
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~L~7~5~4 piece and two-pieceexternally decorated insulated cups with good stacking characteristics and on an economical basis.
srief Description of the Drawings Figure 1 is an elevational view, partly in section, of a nestable insulated container .in accordance with the present invention;
Figure 2 is a fragmentary sectional view, at an enlarged scale, of a cup in accordance with Figure 1, showing a like cup in phantom to illustrate the stacking relationship therebetween;
Figure 3 is a plan view of a rectan~ular blank from which a cup of the type shown in Figure 1 can be fabricated;
Figures 4-8 are schematic views illustrating sequential steps in the fabricating of a two-piece container of the type shown in Figure 1 from a blank of the type shown in Figure 3;
Figures 9 and 10 are schematic views illustrating sequential steps in the fabricating of a one-piece container;
Figure 11 is a schematic representation of an - 7b -~6~7~5~9L

exemplary form of apparatus in accordance with the present invention;
Figure 12 is a cross-sectional view taken substan-tially along the plane 12-12 of Figure 11 illustrating the mandrel pre-heat station;
Figure 13 is a plan view, partially in cross-section, of a sleeve forming apparatus;
Figures 13a and 13b are schematic views illustrating sequential steps in the operation of the sleeve forming apparatus;
Figure 14 is a cross-sectional view, taken generally along plane 14-14 of Figure 11, and illustrating the turret -:
assembly; :
Figure 14a is a fragmentary plan view, partially in cross-section, illustrating the guide track carrier . ~ -assembly for the mandrels mounted on the conveyor chain.
Figure 15 is a plan view of the bottom disc cutting and bottom transfer conveyor systems, with certain portions broken away and others shown in cross-section;
Figure 16 is a cross-sectional view, taken generally along plane 16-16 of Figure 15, with certain portions broken : .
away, and illustrating the bottom punch machine and stock feeder;
Figure 17 is a cross-sectional view taken generally along plane 17-17 of Figure 16;
Figure 18 is an enlarged cross-sectional elevation view taken generally along plane 18-18 of Figure 17;
Figure 19 is a cross-sectional elevation view, taken generally along plane 19-19 of Figure 16 and illustrat-ing a portion of the bottom stock feed system;
Figure 20 is a cross-sectional elevation view, taken generally along plane 20-20 of Figure 16, and i.llustrating a ~7~5~
further portion of the bottom stock feed system;
Figure 21 is a cross-sectional elevation view, taken generally along plane 21-21 of Figure 15, and showing the relationship between the bottom disc transfer conveyor and the main conveyor mandrel;
Figure 22 is an enlarged cross-sectional elevation view taken generally along plane 22-22 of Figure 21;
Figure 23 is a plan view of the bottom disc carrier taken generally along plane 23-23 of Figure 22;
Figure 24 is a cross-sectional view of an alternate shrink tunnel embodiment;
Figure 25 is a cross-sectional view, taken generally along plane 25-25 of Figure 11, and illustrating the bottom sealing turret used in forming a two-piece thermoplastic cup;
Figure 25a is a plan view of the bottom sealing . :
head.
Figure 26 is an enlarged cross-sectional view of a forming mandrel;
Figure 27 is an enlarged cross-sectional view of a cup ejection mechanism and rimming appara-tus;
Figure 28 is a schematic view illustrating sequen-tial steps in the fabricating of a cylindrical sleeve blank;
Figure 29 is a sectional view illustrating the hot air flow control assembly; and Figure 30 is a cross-sectional view of the shrink tunnel taken generally along plane 30-30 of Figure 11.
Detailed Description of the Invention While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail only preferred embodiments of exemplary apparatuses and methods for fabricating the same containers in accordance with the present invention and with _g_ ~L~7~5~L

the understanding that the presen-t disclosure is to be con-sidered as an exemplification of the principles of the inven-tion and is not intended to limit the invention to the specific embodiments illustrated and described. The scope of the inven-tion will be pointed out in the appended claims.
While nestable insulated cups in accordance with the present invention can be constructed in a wide variety of configurations, the presently preferred embodiment of such cup, as is shown generally by reference character 11 in Figs.
1 and 2, comprises a two-piece cup. Cup 11 is formed, as will be hereinafter described more fully, by heat shrinking an open ended cylindrical sleeve about a forming mandrel which has an outer forming surface corresponding to the desired contour of the inside surface of the sidewall of the cup, the sleeve having a relatively high degree of orientation in the direction extending circumferentially thereof. Such a sleeve is formed, in accordance with the preferred embodiment of the method and apparatus of the present invention and as will be hereinafter described more fully, by heat sealing or otherwise joining the opposed lapped ends of a rectangular blank of suitable material in a vertically extending liquid tight seam, and as a consequence of such method of forming, cup 11 will have a visible, vertically extending side seam 12 in the sidewall of the cup, which sidewall is identified by reference character 13.
Sidewall 13 of cup 11 has a major uninterrupted portion 13a, shown as extending from the top of the cup to an inwardly extending stacking shoulder 14 which is located near the bottom of the cup, and which is provided to receive ~he bottom of a like cup inserted therein to provide a positive minimum spacing between nested or stacked cups, as is shown in Fig. 2 and as is well understood in the art. Of course, ~L~73L~4 as is also well understood in the art, equivalent stacking means could be provided in the sidewall of the cup at a relatlvely higher elevation in the sidewall, in which case the major portion of the sidewall would be located below the stack-ing means. In either such event, because of the heat shrink-ing step involved in the manufacture thereof, the thickness of the sidewall of the container decreases as the diameter of the cup increases, and adequate thickness may be provided in the region of the sidewall which is normally grasped by the hand of a user to protect or insulate the hand from the heat of a hot beverage such as coEfee. At the same time, it is possible to maintain the thickness in the region of the top of the cup at a low enough value to form a thin tight bead, shown as 15 in Fig. 1, surrounding the mouth of the container.
Because close nesting of like cups is adversely affected by increased wall thickness, the major portion 13a of the side-wall of cup 11 is shown as increasing in taper, as measured by the included acute angle between the longitudinal central axis of the cup and a line tangent to the sidewall thereof, as the cup diameter decreases and the wall thickness increases, it being noted that increasing wall taper improves close nesting, as is understood in the art.
The bottom or smaller end of Cllp 11 iS shown as being closed by a generally horizontally extending bottom member 16 which is joined to a sidewall portion 13 in a liquid-tight fashion. In the illustrated embodiment, such bottom member is formed from a disc-like element of a thermoplastic material sealable to and compatible with the material of the sidewall, e.g. the same material as the sidewall. This bottom member is joined in a liquid-tight fashion to an inturned por-tion of the sidewall of the cup, as by heat-sealing or with an adhesive, as hereinafter described. However, it is also ~7~

contemplated that such bottom member may be formed integrally with the sidewall of the cup, as is also hereinafter described.
The sleeve from which a cup of the type shown in Fig. 1 may be formed, which is designated by numeral 17 in Fig. 6, is formed from a rectangular sheet or blank of an expanded plastic material, such as expanded polystyrene, ;
such blank being designated by numeral 18 in Fig. 3. The blank is formed by severing from a parent web or sheet of appropriate material, preferably a web of indefinite length of such material which is highly mono-axially oriented in the longitudinal direction. Such a web may be produced, in turn, by slitting a seamless extruded tube of appropriate thermo- ~
plastic material along one or more longitudinally extending -lines which, if there are more than one, extend parallel to one another. The requisite orientation in the machine direc-tion may readily be imparted to such web, or webs, by engaging the extruded tube while it is at a suitable orientation tem-perature be-tween opposed counterrotating rolls which are driven at peripheral speeds substantially in excess of the lineal speed of the thermoplastic material leaving the extruder, all as is well understood in the art.
In practice, it is normally desired that blank 18 be provided with printing or other decorative material on the surface which is destined to be the outer surface of the finished cup. For simplicity, decorative material is shown only in Figure 3 where it is identified by reference character 19, it being understood that it will also be present in other views of the blank, or of the sleeve or cup which are sequen-tially formed therefrom.
This decorative material may be rapidly and rela-tively inexpensively applied, in multiple colors if desired, by applying it in a repeat pattern to the parent web before ~715~

the individual blanks are severed therefrom, as by means of known printing devices such as a flexographic printing press or an offset rotary letter press, all as is well understood in the art. It is to be noted that, because of the differen-tial contraction of the material involved in shrinking a cylindrical sleeve into the form of the sidewall of a nestable cup, the printing should be applied to the web in a form which is distorted from its desired form, so that upon such differential contraction, the printing will change in form into its desired form.
The fabrication of sleeves such as that identified by numeral 17 in Figure 6 from blanks such as that identified by numeral 18 in Fig. 3 is illustrated in Figs. 4 and 5.
Individual blanks 18 are fed to a rotary mandrel head 31.
Mandrel 31 is mounted on shaft 32 and held by collar 33 and set screw 34. Shaft 32 is rotated under power. The blank 18 is held to the mandrel by the vertical row of vacuum ports 35 connected to vartical passage 36 and through radial port 37 into the hollow center passage of shaft 32. The mandrel 31 is concentric with a stripper sleeve 38 carried on a bracket and vertical spindle 39 (Figure 5). Blank 18 is attached at the leading edge 21 to mandrel 31 by vacuum, and as the mandrel rotates, blank 18 is wrapped around the surface of the cylinder, which is the outer surface of the mandrel 31 to form sleeve 17. The stripper sleeve 38 is in its lowered position out of interference with sleeve 17. The mandrel is the desired size (diameter) in relation to the cup forming mandrel that is to receive the sleeve when finished, as hereinafter described.
As the mandrel 31 completes a revolution, the trailing edge of the blank overlaps the leading edge to form a lap seam for the cylinder. The seam is made by heat and ~7~ 4 some pressure in bonding the overlapped regions of plastic :
together, in a liquid-tight seam extending the full height -of the sleeve accomplished by bringing heater 40 into contact with these overlapped areas of the sleeve 17. Heater 40 has a surface layer 40a of Teflon~material to prevent sticking of the heater nose on the sleeve. Heater 40 is pressed against the overlapped p].astic sheet and the combined heat and pressure of heater 40 irons the lap seam into substan- :;
tially less than the double thickness of the overlap. This 10 forms a feathered edge compatible with the thickness of the ~:
remainder of sleeve 17. ~Ieater 40 is on an appropriate carriage to be brought into and out of contact with the sleeve at the proper time and rotation of mandrel 31 during pressure contact of heater 40 as it irons the seam of sleeve 17.
As an alternative, the lap-seam may be made with a hot melt adhesive applied to the inner surface of the blank 18, such as in the area between edge 20 (Figure 4) and phantom line A. Heater 40 will activate the adhesive area and form an adhesive bond between the overlapped ends of the material on mandrel 31.
To fabricate a two-piece cup from a sleeve 17, pro-duced as has heretofore been described, there is provided a ~
forming mandrel shown generally at 41 in Figure 6. Mandrel ..
41 has an exterior surface 41a which is contour.ed to corres-pond to the desired contour of the interior surface of the cup 11 which is to be formed therefrom, or at least the side-wall portion, and the mandrel is suspended from a support member 42. A sleeve 17 which is to be formed on mandrel 41 is telescoped thereover with the upper end of sleeve 17 being held in a position aligned with the maximum dimension of forming surface 41a by means of an expansible clamping ring 43. Clamping ring 43 comprises a series of arcuate sleeve ~7~5~4 contacting segments extending inwardly from an O-shaped spring, and clearance is provided between the clamping ring and the surrounding structure to provide for radial expansion of the ring to accommodate the insertion of the end of a sleeve between the inner ends of such segments and the terminal por-tion of the forming surface 41a of mandrel 41. Clamping ring 43 is retained in a fixed position relative to the axis of mandrel 41 in a cavity ~8 of support member, to the bottom of which is attached a removable flange 49 on which clamping ring 43 slidably rests.
As is shown in Figure 7, when sleeve 17 is positioned over the forming surface ~la of mandrel 41, the so positioned elements are exposed to a source of heat, as by advancing them in unison into a region, exposed to infra-red heating elements 51, 52 and 53, elements 51 and 52 being directed against opposed sides of mandrel 41 and element 53 being directed against the bottom thereof. For purposes of illustration, elements 51-53 may be considered to be electric elements of the type manufactured by Irex Corporation of Riverdale, New Jersey and sold as Radplane ~radiant process heaters. As an alternative to heating by way of infra-red elements, it is also contemplated that the so~positioned sleeve and mandrel could be heated by advancing them through a tunnel through which heated air is circulated. However, infra-red heating has been found to be more controllable and, because of the penetrative effect of the infra-red radiation, somewhat faster than forced convection heating. In any event, the application of heat will cause the portion 17a of sleeve 17 which overlies the side portion of the surface 41a to shrink into tight con-forming relationship therewith.

To avoid chilling of the interior surface of thesleeve during shrinking which would, of course, inhibit ~7~

shrinking, it has been found desirable that the mandrel be at an elevated temperature during the shrinking step, but not at a temperature higler than the softening point of the thermo-plastic material from which the sleeve is formed. With sleeves formed from expanded polystyrene, good results have been obtained with a mandrel pre-heated to a temperature on the order of from about 150F to 170F.
Prior to the exposure of sleeve 17 to the heating effect of heating elements 51, 52 and 53, a disc-shaped ele-ment of thermoplastic material 71, from which bottom element16 of the finished cup is to be formed, is brought into posi-tion against the bottom of mandrel 41 in coaxial relationship to sleeve 17. Element 71 is retained in such position durin~
the heating step by vacuum applied thereagainst through a circumferential series of ports 44 which are in fluid communi-cation with vacuum line passages 45 and 46 extending through a central spindle portion 47 of mandrel 41 and, in turn, communicating with a vacuum source, not shown, external to the mandrel. The use of a pair of such vacuum line passages, 45 and 46, makes it possible to maintain a vacuum in the annular space defined by the outer surface 41a of mandrel 41 and the central spindle 47 thereof. While such vacuum is not utilized in the illustrated embodiment of the invention, it can be ~ -utilized to advantage by providing vacuum ports through the surface 41a to help in the forming of sharp corners in an upper portion of the finished cup, as in the case of a cup -having a stacking rim in an upper portion thereof or a cup formed from very thin and/or very low density material and thereby requiring a circumferentially extending stiffening rib near the upper portion thereof.
While the portion of sleeve 17 which overlies the side portion of the surface 41a of mandrel has shrunk into 1C1~7~5~

conformity therewith, as heretofore explained, the terminal portion of sleeve 17 which extends beyond the smaller end of the mandrel 41 will continue to shrink to form an annular, generally planar portion 17b which is integral with and extends inwardly from the smaller end of portion 17a, and which over-laps the marginal portion of element 71 in a continuous, circumferential pattern. In the meanwhile, the interior portion of element 71 will permanently shape itself to con-form to the concave curvature of the bottom of mandrel 41 by the effect of the heat and vacuum force to which it is exposed, some vacuum naturally bleeding from ports 44 into the region above the interior portion of element 71. After the shrinking operation, the mandrel 41 with the shrunken sleeve 17 and the shaped bottom element 71 thereon is removed from exposure to heating elements 51, 52 and 53 and, as is shown in Figure 8, a heated sealing tool 61, with a non--stick contact surface layer 61a such as a woven glass fabric, for example, of the type sold under the designation Flour ~ glass, which is im-pregnated with Teflon~ resin or other non-stick material, is brought into pressing contact therewith to form a continuous, circumferentially extending, liquid-tight heat seal between portion 17b of sleeve 17 and the underlying marginal portion of element 71.
After the seal has been effected between portion 17b of sleeve 17 and the underlying portion of element 71, as has been described, the shrunken sleeve is stripped from the mandrel and is further processed in a conventional manner, for example, by rolling the rim 15 therein by means of con-ventional rim forming devices, by inspecting finished cups and by collecting and packaging a multiplicity of like cups in nested relationship with one another.

A cup of the type shown in Figures 1 and 2 may also ~(~7~l5~

be formed of one-piece construction, as well as of two-piece construction as heretofore described. Such a cup may be con-structed, as is shown in Fi~ures 9 and 10, from a sleeve 80 which is the same as sleeve 17 except that it is longer and has a relatively long portion adapted to extend beyond the smaller end of the forming mandrel, which may be considered to be the forming mandrel depicted in Figures 6-8. In such a case the starting sleeve from which the cup is to be formed is of sufficient length to have a substantial portion which extends beyond the smaller end of the mandrel 41 when the upper edge of such sleeve is in its aligned position with the upper portion of the forming surface of the mandrel. Upon -the heat-shrinking of such a sleeve, as is shown in Figure 9, it will form a member with a sidewall portion 80a, a generally planar annular portion 8Ob integral with portion 8Oa and extending radially inwardly from the lowermost edge thereof, and a relatively small tubulation 80c which extends longitu-dinally from the interior edge of the planar portion 80b and which is integral with sidewall portion 80a and annular por-tion 80b. The bottom of a cup may be formed in the shrunken member 80, preferably while such member is still on the mandrel, by the application of heat and pressure to the bottom of such member to cause the tubulation 80c to collapse and fuse to-gether with planar portion 80b~ This may be done by means of a pressing and shaping tool 90 which has a contoured surface adapted to contact the bottom of the shrunken sleeve and to shape it to the desired final configuration. Tool 90 is normally in a non-contacting position relative to mandrel 41, as is shown in Figure 9, and it may be urged from such posi-tion into the sealing and pressing position depicted inFigure 10 by the action of a spring 91. As the shrunken sleeve 80 on mandrel 41 may not be at a sufficiently high temperature :~7~5~9L

at the time that tool 90 is brought into contact therewith to permit the sealing and pressing operation to be performed without addltional heat, tool 90 may be considered to be heated by means, not shown, and to have its contact surface covered with a material 9Oa of the type used in regard to the contact surface 61a of the tool 61 of Figure 8, as heretofore described. In case that the bottom sealing step in the manu-facture of either the two-piece cup, as is shown in Figure 8, or of the one-piece cup, as is shown in Figures 9 and 10, is done while the shrunken sleeve elements are at a sufficiently high temperature to obviate the need for additional means to heat the applicable sealing tool, an unheated sealing tool may be used, in which case it will normally be unnecessary to coat the contact surfaces of the sealing tools with the special non-stick material of surfaces 61a or 90a, as the case may be.
In general, it is recommended, for good stacking characteristics, that the sidewall taper of cups or other nestable container constructed in accordance with the present invention increase from a taper of the order of 5 - 7 at the top thereof to a taper of the order of at least 15 at the bottom thereof. To obtain a good balance between per-formance and cost, for a cup of the order of size of a single serving of coffee or other hot beverage and based on current economic conditions, a starting or parent sheet of expanded polystyrene of a thickness of the order of 20 to 30 mils, of a density of the order of lO to 18 pounds per cubic foot, and with an orientation in the longer or machine direction of the order of 75% and an orientation in the shorter or cross direc-tion of the order of 15% is preferred, with sheets of adensity of the order of 10 pounds per cubic foot and a thick-ness of the order of 25 mils (0.025 in) being highly satis-5~4 factory for the fabrication of single serving hot drink cups.
However, while heat-shrinkable, expanded polystyrene is cur-rently the preferred material for the fabrication of insulated cups and other nestable containers according to the present invention, such preference is based mainly on the cost of polystyrene relative to other thermoplastic resins. Such cost relationships could change with the passage of time, and it is therefore to be noted that other heat-shrinkable, expanded thermoplastic materials can, from a technical point of view, be employed in the practice of the invention, including such materials as polypropylene, polyethelyne and polyvinyl chloride. It is also to be noted that cups constructed in accordance with the present invention can be used as cold drink cups, where the insulating properties would not be as important, but would still be of value in preventing moisture from condensing on the outer surfaces. In the case of cups or other containers designed for holding cold drinks or for other fluent products at ambient temperature, the use of an expanded thermoplastic material would offer potential benefits, in relation to non-expanded materials, chiefly in reduced material costs.
While the invention has been described with respect to a nestable container which is circular in cross section at all elevations, it is to be noted that other configurations can be provided to suit the wishes of the designer. For example, a nestable container which has the cross section of a round-cornered square at all elevations can be provided, and a nestable container which has a circular cross section at the top gradually merging into the cross section of a round-cornered square at the bottom can be provided. Also, whereclosed nesting is not required, an attractive nestable con-tainer with a sidewall having a reverse curvature, similar to ~6~7~L5~L~

the popular "Coke"~tumhler, can be provided. Containers which are non-symmetrical can also be provided.
It is also to be noted that the present invention can be practiced with non-expanded, heat-shrinkable thermo-plastic materials in cases where the nestable cups or other containers do not require thermal insulating characteristics.
Such containers would still have advantages over containers formed from such materials by vacuum forming or other sheet drawing techniques, in regard to the ease and relatively low cost with which the sidewall thereof could be decorated. Also, by virtue of the mode of manufacture thereof, such containers, being fabricated from rectangular blanks, would involve a considerably lower amount of scrap to be reground and recycled, and would inherently avoid the problem of excessive thinning in the sidewall region near the bottom which is characteristic of such containers when formed by any such popular s~eet drawing techniques and which, in regard to relatively tall, narrow containers, can lead to a significant reduction in the strength in the bottom regions of the sidewalls of such containers.
It is thought that the container of the present invention may be better understood from the following example, which is not to be construed as limiting the scope of the invention in any way.
Example The sidewalls of two-piece cups of the outline of that shown in Figure 1 were constructed from preprinted rectangular blanks of 10 pounds per cubic foot density poly-styrene, 9 3/8 in. long by 4 in. wide by 25 mil (0.025 in.) thick, such blank having 75% orientation in the longer or machine direction and 15~ orientation in the shorter or cross direction. The bottom elements were fabricated from poly-~7~

styrene sheeting of the same specifications. Each finished cup had an overall height of 3.448 in., and I.D. at the rim of 2.920 in. and I.D. inside of the stacking shoulder of 1.892 in., a wall thickness, at the rim, of 30 mils~ a wall thick-ness, immediately above the stacking shoulder, in excess of 40 mils, a curved sidewall curving along the arc of a circle of a radius of 12 5/8 in:. from a taper of 5 30' at the rim, and an O.D. over the rim of 3.155 inches. The stacking dis-tance or height between the bottoms of like cups in a nested relationship was 0.390 inch. Each such cup had a volumetric capacity to overflowing of 9 fluid ounces and such cups were found to be very well suited, in rigidity, liquid imperme~
ability and insulating properties for hot beverages such as coffee. Cups of similar design have also been satisfactorily constructed from expanded polystyrene sheets of the following thicknesses and densities: 1) 18 pounds per cubic foot and 25 mil, 2) 10 pounds per cubic foot and 30 mil, 3) 15 pounds per cubic foot and 20 mil, and ~) 18 pounds per cubic foot and 25 mil.
But for some differential post-expansion of the foam sheet which is apparently caused by differential appli-cation of heat thereto and which led to some increase in density in the sidewall of the cup in the region of the rim, the density of the cup sidewall remained relatively uniform throughout. As a result, it could be fairly said that the product of sidewall circumference at any elevation and thick ness at that elevation remained relatively constant through a major portion of the cup.
Referring now to Figures 11-30, which illustrate the previously described apparatus for making the two-piece cups in more detail, the reference numbers to certain elements which have been previously described have been increased by 31 ~7~5~4 100 to facilitate reference back to the previous descriptive matter, and unless otherwise indicated, the elements corres-pond to the elements described above.
Figure 11 is a schematic plan view of a preferred embodiment of the apparatus of the present invention in its entirety and the apparatus may be considered to be comprised of a plurality of separate working stations, or subassemblies, which are hereinafter discussed individually. The separate working stations, or subassemblies are representative of various steps that are performed in the process of the present invention, and are discussed essentially in the sequence in which they are performed. With specific reference to Figure 11, and beginning approximately at the "12 O'Clock"
position, a main conveyor 250 having a plurality of spaced mandrels thereon moves in a counterclockwise direction to a mandrel preheat station 300, a sleeve forming station 400 ("9 O'Clock" position) which includes a web handling and feed subassembly and a sleeve transfer subassembly, a bottom disc cutting station 500 ("6 O'Clock" position) which includes an initial bottom disc conveyor and a final bottom disc conveyor which transfers the discs to the main conveyor, a shrink tunnel 700, a bottom forming station 800 ("3 O'Clock" position) and a rim forming station 900. While the various mechanisms and process steps are hereinafter discussed individually, it should be understood that the various s-teps and operations are performed in timed sequence in proper interrelationship with respect to one another, so that the various mechanisms co-operate in the form of a true combination.
The main conveyor 250, which transports the cup forming mandrels 141 through the above-mentioned series of operational stations, moves continuously along a closed path in the form of a flattened ellipse, although it should be ~7 lL5~

understood that paths having other shapes, such as circular, are within the contemplation of the invention. A blank 118 of thermoplastic material o predetermined length is Eed onto sleeve forming mandrels 131, which are turret mounted beneath the main conveyor 250 at station 400. The blanks 118 are then sealed along their end portions to form a sleeve 117, which is telescoped upwardly by a stripper sleeve 138 to the main conveyor mounted mandrels 141 which have been preheated prior ~-to reception of the sleeve 117. The main mandrel conveyor 250 then transports the sleeves 117 to the disc transfer con-veyor 600 to receive the bottom discs 171.
The bottom discs 171 are cut two at a time from two webs of stock 501 by dual die cutters at the bottom disc cut-ting station 500. The cut discs 171 are then serially trans-ferred by a linear conveyor 560 to the disc transfer conveyor 600 which places the individual discs 171 on the bottom of the forming mandrel 141.
After receiving the bottom disc 171, the cup forming mandrels 141 are conveyed through the shrink oven or tunnel 700 wherein the sleeve blank 117 is shrunk to the contour of the forming mandrel 141, with the end portion 117b of the sleeve overlapping the bottom closure disc that has been pre-viously placed on the mandrels. After emerging from the shrink tunnel, the forming mandrels move to the bottom forming sta-tion 800 where a sealing die forms a fluid tight seal between the bottom portion 117b of the shrunken sleeve and the disc.
The formed cup 111 is then conveyed to the rimming station 900 where the cup is removed from the forming mandrèl 141 and deposited in a cup die. The cup die is then conveyed to a rimming mechanism which is reciprocated into engagement with the cup die to form the circumferential bead rim 115, thus completing formation of the cup. The finished cups are then ~7~S~L~

removed from the rimming station conveyor, and the empty cup die receives a formed cup 111 which is to be rimmed. After having deposited the partially formed cups in the rimming station cup die, the main forming mandrels are conveyed to the mandrel preheat station 300 and the entire operation is repeated.
Main Conveyor and Drive Therefor The main conveyor 250 includes two endless chains 260 (Figures 14 and 25) spaced vertically from one another, and a plurality of spaced mandrel support members 252 are connected to chains 260 by brackets 261 that extend vertically between chains 260. Each bracket 261 includes upper and low-er support portions 261a on the inside surface of a flat plate 261b, with each support portion 261a having an inwardly fac-ing recess within which a chain 260 is pinned. Chains 260 are driven at the right hand end turn by conveyor shaft 810 (Figures 11 and 25), and vertically spaced, horizontally disposed sprockets 234 and 235 disposed at the level of the recesses within support portions 261a. The chains 260 are 20 carried on spaced idler sprockets 234' and 235' disposed vertically from the left hand end turn shaft 810'.
Guide track carriers are mounted on the frame of the machine at opposite ends of the path of the main conveyor, and each guide track carrier 266 includes a hub 266a that is secured in free running relationship with respect to shafts 810 and 810' by vertically spaced bearings 810a. Each hub 266a is associated with its respective bearings 810a by clamping rings 266b and bolts 266c, and carriers 266 are secured to the frame of the machine by bolts 266f which are 30 threaded into frame member 266g. With reference to Figure 14a, frame members 266g, are parallel to one another and spaced outwardly of the axis of shaft 810 at the left hand end of ~L~7~S~

the conveyor path. As is also evident from Figure 14a, the -carrier member at the left hand end of the machine is provided elongate slots 266h that are impaled by bolts 266f, so that the left hand carrier member 266 can be adjusted relative to -the carrier member at the right hand end of the machine. An adjusting screw 266i is threaded through a support that is carried by transverse frame member 266j, and bears against the left hand carrier member 266 to effect adjustment thereof.
The right-hand carrier member is secured in fixed relationship with respect to the prime mover which rotates the shaft 810 at the right-hand end of the conveyor path.
Carrier members 266 further include a horizontally disposed web portion 266d extending outwardly from hub 266a, with a series of circumferentially spaced, vertical flanges -266e being provided at the outer end of web 266d. Four flanges 266e are spaced at 60 intervals around the outwardly facing end portion of each carrier member, as can be seen in Figure 14a with two flanges being disposed transversely to the straight portion of the main conveyor path and with two flanges being disposed to trisect the 180 end turn.
Means are provided on carrier members 266 for guiding and positively supporting chains 260 as the main conveyor moves around opposite ends of its path, and said means includes a plurality of mounting blocks 265, each being secured to one of flanges 266. The guiding means further includes an arcuate upper guide member 262 that is secured to the upper surface of blocks 265 by bolts 262a, with guide member 262 having an arcuate downwardly facing guide track;
an arcuate intermediate guide member 263 that is secured to the outer surface of blocks 265 by bolts 263a, with guide member 263 having an outwardly facing arcuate guide track;

and an arcuate lower guide member 264 that is secured to the ~7~5~

lower surface of blocks 265 by bol-ts 264a, with guide member 264 having an upwardly facing arcuate guide track.
A first vertically disposed roller 254 is connected to an inwardly extending, horizontally disposed flange 254a (Figure 25) on bracket 261 by bolt 254b, and roller 254 extends upwardly to be received within the downwardly facing arcuate guide track in upper member 262. A second horizontally extending roller 255 is connected to an intermediate portion of bracket 261 by a bolt 255a, and roller 255 extends inwardly to be received within the outwardly facing arcuate guide track in intermediate guide member 263. A third roller 256 is connected to an inwardly extending horizontally disposed flange 256a adjacent the lower portion of bracket 261 by bolt 256b, and roller 256 extends downwardly to be received within the upwardly facing arcuate guide track in lower member 264.
A similar guide system is provided for chains 260 in the straight section of the conveyor path, and the struc-ture thereof can be best understood by considering Figures 12, 14a and 24. As shown therein, a pair of inwardly facing U-shaped plates 229 extend horizontally between the ends oftransverse frame members 266j, and plates 229 are supported by downwardly extending L-shaped brackets 233. T-shaped mounting blocks 265 are secured to the outer face of plates 229 at spaced intervals by bolts 229a and spacers 229b. Upper and lower guide members are secured to blocks 265 by bolts ~not shown), and provide vertically aligned, straight upper and lower guide paths 230 and 232, respectively. An inter-mediate guide member is secured to the outer face of the leg of mounting blocks 265, and provides an outwardly facing, straight guide track 231 that is parallel with guide tracks 230 and 232. Guide tracks 230, 231 and 232 are positioned in aligned communication with the guide tracks in members 2629 5~4 263 and 264, respectively, to provide a smooth transition between the arcuate and straight portions of the conveyor path as rollers 254, 255 and 256 traverse the guide slots.
In the illustrated embodiment, the main conveyor 250 is driven from the right hand end thereof, and the drive is transmitted to shaft 810 by a worm 814 (Figure 25) mounted on bracket 815 and a worm gear 816 carried at the lower end of shaft 810. Worm 814 is rotated by a suitable prime mover (not shown). Worm gear 816 is mounted on a vertical stud 813 by spaced bearings 817, and shaft 810 is fixedly attached to the hub of gear 816 for rotation therewith by bolts 818 that extend through an enlarged sleeve or flange at the lower end of shaft 810.
Each orming mandrèl 141 is rotatably mounted upon a spindle 147, Figure 26, which is integrally formed at the lower end of support member 252. The upper end of the members 252 are flattened, and are secured in surface abutting engage-ment with the outer face of plates 261b by bolts 258. Mandrels 141 are each supported on a spindle 147 by a mounting assembly which includes a collar 270 having circumferentially spaced flanges 271 at its lower end which are secured by bolts 274 to an outwardly extending flange 141a at the top of the mandrel 141. A bearing 269 is positioned coaxially within each collar 270, and is retained around its respective mandrel 141 by clip rings 272 which are located in circular recesses in the spacer and which bear against the upper and lower surfaces of collar 270. The mounting assembly is positioned and retained in place on spindle 147 by a thrust bearing 273 and an annular member 147a threaded to the spindle 147.
Mandrel Preheat Station As described above, it is desirable that the forming mandrels be at an elevated temperature during the shrinking ~6~7:~L5~L4 step to prevent the formation of wrinkles in the sides of the cup, and to this end the mandrels are passed through the pre-heat station 300. The preheat station Figure 12, is located upstream from the left-hand arcuate end turn, and includes an infra-red heater 320 on one side of the conveyor path at the level of the mandrels and reflector structure 301 beneath the conveyor path and on the side thereof opposite from heater 320.
Heater 320 may be the same as, or similar to, heaters of the type described above to shrink sleeve 17, i.e., an electrical element of the type manufactured by Irex Corporation of Riverdale, New Jersey and sold as Radplane radiant process heaters. The particular reflector elements illustrated in Figure 12 are L-shaped, with a first leg 301 extending below the mandrel path, and with a second leg 301b extending upwardly above the lower forming section of the mandrels. Reflector leg 301b is secured to vertical frame members 304 by means of insulating spacers 302 and 303, and anchor bolts 305. Reflec-tor leg 301a is secured to horizontally disposed frame members 307 by means of an insulating spacer 303 and anchor bolt 305, 20 and heater 320 is also secured to frame members 307 outwardly of the end of reflector leg 301a.
The upper portion 142 of the forming mandrel i5 provided a collar 270 formed with a circumferential recess 251. A horizontal rail 308 is secured to frame members 304 by means of studs 306, and rail 308 extends the length of the preheat station. Rail 308 extends outwardly from frame members 304 and engages within mandrel recesses 251 as the mandrels traverse the preheat station. Rail 308 is preferably made from a resilient material, so that proper frictional contact 30 may be maintained between rail 308 and recesses 251 to rotate the mandrels about their vertical axis as they pass through the preheat station. Illustratively, mandrels 141 may be ~7~5~4 heated to a temperature in the range of 150-160F. in the preheat station, and the degree of heating will, of course, vary depending upon the character of the plastic used for the sleeves, i.eO its composition and thickness. It should be appreciated that after conditions at thermal equilibrium have been reached, the step of preheating the mandrels may be omitted.
Web Handling and Feed The web handling and feed system i5 similar in many respects to the system described and claimed in S. W. Amberg et al,Canadian patent 974,108.
As described above, the sleeves 117 are formed from a continuous web of stock. With reference to Figure 11, the thermoplastic web stock 415 is supplied from roll 415a which is supported outwardly of the left-hand and the main conveyor path on a rotary stand with a vertically disposed axis. The decorated surface, if any, of the web stock 415 is on the outer surface of the stock wall. The web stock 415 is con-tinuously fed with a vertical orientation along a path past a guide roller 416 and between adjacent S-wrap guide rollers 417 and 418. The web stock 415 next passes between the nip of a pair of feed rollers 419 and thence, onto feed drum 420 adjacent the path of the main conveyor. Web 415 goes onto feed drum 420 with the printed surface (if any) facing in-wardly on the drum. When the web stock is decorated with a repeat pattern, a photo registration unit (not shown) may be provided between guide rollers 417, 418 and feed rollers 419 to maintain the linear relationship of the repetitive decora-tion. A rotary vertical cut-off knife 421 adjacent feed drum 420 severs the web stock at preselected intervals to provide appropriate length blanks of material for forming the container sidewall.

:~73~5~L

After the web 415 passes through the feed rollers 419, the leading edge of the web is held against the vertical cylindrical surface of the feed drum 420 by vacuum applied to a vertically arranged series of ports. Feed drum 420 corres-ponds to element 92 in above-mentioned Canadian patent 974,108, and reference may be made to this patent for details not shown or specifically described herein. The surface of the feed drum 420 is provided with three equally spaced apart sets of vertical ports which receive vacuum from a suitable source.
Each set of ports comprises two vertical rows of ports to which vacuum is selectively directed so that the leading row of ports first receives vacuum to pick up the leading edge of the web 415 just as the previous blank is cut by the rotary knife 421; and thereby controls the leading edge of the web to hold it on feed drum 420 as the knife severs the material.
The second or trailing row oE vacuum ports in each set are in contact with the web 415 previous to the cutting thereof and exerts a pulling force in the web to keep the material taut between rollers 419 and the feed drum.
When the rotary knife 421 has completed its cutting action against the vertical face of the feed drum 420, the leading ports will apply vacuum to the web 415 at the inter-face with the drum. The feed drum 420 has a higher peripheral velocity than the web material fed by rollers 419, and the difference in surface speed generates a slip-clutch effect between the vertical face of the drum 420, the leading and trailing vacuum ports, and the web 415. This slip-clutch effect (see Figures 17a and 17b of Canadian patent 974,108) will cause the leading vacuum ports to advance the leading edge of the web 415 and subsequently lose contact. Before this occurs, the trailing ports will have engaged the web 415 and thereby maintaln a continuity in the slip-clutch effect.

~L~7~4 After the web 415 has been cut by knife 421, the blank 118 assumes the velocity of the drum surface. This causes a gap to occur between the trailing edge of blank 118 and the lead-ing edge of web 415 providing the timing of the successive blanks 118 and mandrels 131 which are rotated into tangential relationship with the vertical surface of the feed drum 420.
The slip-clutch effect, just described, that occurs between the feed drum 420 and the web 415, applies a tension to the material between the feed drum 420 and feed rollers 419 and holds the web taut therebetween. When the feed drum 420 reaches its closest tangential relationship with a mandrel 131, the vacuum ports which are holding the blank 118 on the feed drum, are supplied with a short puff of positive air pressure which releases the leading edge of blank 118 from the surface of the feed drum 420. The clearance between the mandrel sur-face and the feed drum surface interface at this point is about one and one-half times the thickness of the blank 118.
When a transfer interface occurs, i.e., where the center axis of a mandrel 131 coincides with the diametrical line connection 20 between the rotary center of feed drum 420, the blank 118 is transferred from the feed drum onto the mandrel. The blank 118 is then carried on the mandrel 131 by means of the set of vertically spaced vacuum ports described above in connection with Figure 4.
Mandrel Mechanism A plurality of sleeve forming mandrels 131 are rotatably mounted by bearings in the spokes of a turret 422 which rotates about shaft 810' at the left-hand end and below the main conveyor path as can be seen in Figure 14, which shows a mandrel in the sealing position. Turret 422 is comprised of a hub portion 422a, a plurality of radial spokes 422b, extending outwardly from the hub, and supported by a web por-~C17~5~L

tion 422c~ The outer end of each spoke is bored to receive a vertical shaft 132 which is supported by bearing 132a, and the forming mandrels 131 are provided at the upper portion of shafts 132. Shafts 132 are located on a common radius with the path of movement of the forming mandrels 141 at the curved left-hand end of main conveyor path, and the sleeve mandrels 131 and the mandrels 141 move into vertical registry at the left-hand end of the conveyor path and remain in vertical registry for 180 of rotational travel.
The vertical vacuum ports 135 in each mandrel 131 receive vacuum through an internal chamber 137 (Figure 13a), and the vacuum is supplied from an annular manifold block 423 mounted above the turret 422 (Figure 14). Manifold block 423 communicates with chamber 137 in each mandrel through a radially disposed hose 424 which is connected at the end remote from chamber 137 to suitable source of vacuum by a fitting.
Mandrels 131 are rotated by a gear train system 426 best seen in Figure 14 herein, and shown in even greater de-tail in Figures 14-16 of Canadian Patent 974,108. The gear train system converts the continuous rotary movement of turret 472 into intermediate rotary movement of mandrels 131, and to this end, each mandrel is provided with a gear 426a at the lower end of shaft 132 which meshes with a gear 426b. A
vertical shaft 426c parallel with each shaft 132 is mounted at its upper end in the lower portion of spoke 422b of turret 422 by a bearing 426d and at its lower portion by a bearing 426d which is located in a bracket 470 extending from a flange at the lower end of turret 472. Shaft 426c is driven by a rack and pinion system mounted beneath the flange of tur-ret 472 in housings 471. This system includes a drive pinion 426e which is keyed to the end of shaft 426c extending below ~L~7~5~

bearing 426d and is in mesh with rack gear segment 426f. Each rack gear 426f carries a cam roller 473 which is attached to the underside o~ the gear segment by pin 474.
Roller 473 travels in an upwardly facing cam groove 475 formed on the top surface of a stationary cam plate 476 which defines an endless cam path about turret 472. Cam plate 476 is rigidly held on the ends of horizontally disposed arms 477 which are attached to the frame base platform 452 at spaced intervals circumferentially around turret 472 by verti-cal support posts 464. The cam path is contoured to produce540 rotation of the forming mandrels 131 immediately after the leading edge of the blank has been positioned thereon to wrap the blank around the mandrel and to locate the overlapping edge portions in a position facing inwardly toward the seam forming apparatus to be hereafter described. The afore-described 540 rotation takes place as turret 422 rotates from the blank pickup position adjacent drum 420 to a six o'clock position, where a dwell portion of the cam 475 terminates rota-tion of the mandrel after which the blank 118 is seamed to form a cylindrical sleeve 117. A gradual rise in the cam will reset the rotational position of mandrel 131 180 for re-ceiving another blank just as the mandrels 131 rotate into register with mandrels 141. The mandrels then remain station-ary as they move into vertical registry with the overhead forming mandrels 141 where the sleeves are transferred to mandrels 141.
Turrets 422 and 472 are in fixed relationship to one another for conjoint rotation. A worm gear 816' is attached to the lower end of turret 472 and driven by a worm (not shown) which is rotated on a common drive shaft with worm 814 (Figure 25).

After the mandrel rack and pinion drive system has ~L~7~5~

rotated mandrel 131 through 540, the overlapping ends of the blank 118 are seamed. Referring to Figures 13a, 13b and 28, the seaming apparatus of the present invention utilizes a combination of hot air and cold clamping to create a smooth liquid tight seam between the overlapping portions of blank 117. To this end, each mandrel is provided with a sealing system which is located above turret 422 and positioned on a support ring 432 (Fig. 14) which is attached to the upper surface of the turret spokes 422b by vertical support column 433 and horizontal bracket 434.
The individual seaming systems for each mandrel 131 are located on a radius of turret 422 which intersects the center axis of its respective mandrel.
Referring to Figure 28, at position 1 after the leading edge of blank 118 has been picked up on a mandrel 131 by its vertical row of vacuum ports 135, the mandrel is rotated by its rack and pinion system 426 through 540, as described above. As the mandrel passes 180 of rotation (position 2), a carriage assembly 435 (discussed below) is cammed radially toward the mandrel so that a vertically elongated roller 436 extending the height of the blank 118 contacts the surface of the blank to support it on the mandrel. When the mandrel 131 completes 540 of rotation (position 3), the vertical edges of blank 118 are presented in overlapping relationship. Hot air is then directed to the overlapping edges from converging nozzle 427a to soften the thermoplastic material. The hot air acts simultaneously on both edges of the blank thus shorten- ~
ing the time necessary to seam the blank. The hot air prefer- ~ -ably has a temperature in the range of 550-650F. to soften the thermoplastic material of the type contemplated by the present invention.

As the hot air is directed toward the overlapping -~71~

edges, the trailing edge of blank 118 is oriented against the flow of hot air and tends to be lifted from the surface of mandrel 131, thus forming a V-shaped pocket with the leading edge of the blank to receive hot air. Roller 436 remains in contact with the blank adjacent the trailing edge so that the trailing edge is in the proper attitude to the flow of hot air.
After the edges of the blank 118 have been softened, a cold clamping bar 429 is cammed against the overlapping edges and the softened surfaces unite to form a seam, thus completing the formation of a cylindrical sleeve 117. At this time, vacuum to ports 135 is terminated, so that the sleeve 117 may be subsequently removed from mandrel 1310 The hot air is diverted from the blank 118 as the clamp 429 is cammed against the blank to prevent distortion of the side-walls (position 4). After the edges have been seamed, the clamp 429 and roller 436 are moved out of contact with the sleeve 117 (position 5) and the mandrel enters the sleeve ejection position where the sleeve is telescoped onto the ;
; forming mandrels 141.
Referring to Figures 13, 13a, 13b and 29, the hot air is directed from an air regulator 427c which supplies air at a suitable rate, such as, for example, 6 7 cfm., to the lower end of an air heater assembly disposed vertically to and adjacent each forming mandrel 131. The air heater assembly comprises a vertical elongated chamber 427 which receives air from regulator 427c through tubing and fitting 427i and which is open at the top 427b to allow air to escape upwardly. A
suitable heating element (not shown) is located within the chamber 427 which heats the air as it passes therethrough.
Each air heater assembly is mounted on a horizontal plate 427e, which is secured to the upper surface of a turret spoke 422b by bolts 427f. Plate 427e is provided with an upright support , ~(~7~5~L

427g to which the air heater assembly is mounted by box brackets and bolts 427h. A movable cover 428 is provided over an opening at the end of duct 427, so that after the blank 118 has been wound on mandrel 131 and seamed, the hot air may be directed away (Figure 13b) from the sidewall of the seamed tube to prevent distortion thereof.
Cover 428 is controlled by a vertically disposed linkage system 428a, Figure 29, and the cover is spring loaded toward an open position. The linkage system includes the cover 428, which is pivotally mounted to a support 428b at the upper portion of chamber 427 by pin 428co The cover 428 thus forms a lever and the end of the cover opposite chamber 427 is pivotally connected to the upper portion of vertically disposed link 428d by slide pin assembly 428e. Slide pin assembly 428e is biased upwardly by a spring 428f, and an adjustment collar 428g is threaded on the upper end of link 428d, so that the cover opening may be adjusted. It will be ;
appreciated that longer cover closure times will be necessary as the speed of the machine is increased and the above des-cribed adjustment means gives the machine the flexibility of accommodating different production rates.
Link 428d is biased downwardly by a spring 428h that is connected to plate 427e, so that cover 428 is urged into the open position. The lower portion of link 428d is pivot-ally connected to an operating lever 428i by pin 428j, and lever 428i is pivotally attached by a pin 4281 to a fulcrum block 428k mounted on the upper surface of plate 427e. The other end of lever 428i carries a spherical cam follower 428m which rides on an arcuate cam 428n mounted on turret spokes 422b. Cam 428n has a low portion which causes cover 428 to close immediately after the blank 118 has been wound about -mandrel 131, so that hot air is directed to the interface ~7~5~9L
between the overlapping end portions of the blank 118. After the cold clamp 429 engages the overlapping ends of blank 118, the cam surface drops and the cover 428 opens.
The cold clamp 429 is mounted on a radius of the turret 422, and is reciprocated in a radial plane through the center of rotation of the mandrel 131. The vertical operative surface 429a at the outer end of the clamp is designed to produce a vertical seam between the softened overlapping edges of blank 118. Each clamp 429 is attached to a piston rod 430 extending through a cylinder 431. The piston rod 430 is spring loaded (not shown) inside the cylinder 431 to normally urge piston rod 430 radially inwardly, and this retracts clamp 429 so that it is stopped in contact with the outwardly facing sur~ace of an annular stop ring 479. Ring 479 is mounted concentric with shaft 810' above turret 422, and supported thereon by brackets 434. Each bracket 434 includes a vertical column portion 434a which supports stop ring 479 from the upper surface of turret 422. Radial access slots 479a are provided in ring 479 at spaced circumferential loca-tions to permit piston rod 430 and cylinder 431 to extend therethrough. Cylinder 431 is attached to an annular support ring 432 which is mounted on turret 422 by vertical columns 433 that extend upwardly from the ends of horizontally disposed cantilever portions 434b of brackets 434, as shown in Figure Each clamp 429 is secured in an outwardly facing vertical slot in a carriage assembly 435 (Figure 13), and a vertically disposed roller 436, is mounted in side-by-side relationship with respect to each clamp by shafts 436a. A
spring 437 surrounds each shaft 436a and biases the shaft outwardly to provide a yieldable force for holding blank 118 on mandrel 131. Each carriage 435 is controlled by the move-~g~37~5~L~

ment of its piston rod 430, and the end of the piston rod 430 opposite the clamp 429 is provided with a cam follower 430a which rides on the vertical face of a lateral cam 430b. Cam 430b is stationary and is fastened by a hub 430c on the vertical stationary shaft ~lOc concentric with shaft 810'.
Cam 430b extends circumferentially of turret 422 through an arc of travel spanning the seaming cycle (Figure 28). Accordingly, roller 430a engages cam 430b while a man-drel 131 starts to wind a blank 118 around itself so that roller 436 will contact the side of the blank on the mandrel approximately after 180 rotation of the mandrel. As is clear from Figure 13 and the No. 2 position of Figure 28, roller 436 e~tends outwardly beyond the end of clamp 429, so that clamp 429 remains spaced from the blank as it is being wound. A
subsequent high portion in cam 430b causes the clamp 429 to press against the overlapping softened ends to form the seam and the side walls of sleeve 117. During this latter movement, roller 436 moves inwardly against the bias of spring 437.
After the sealing cycle is completed, roller 430a runs o-ff cam 20 430b and the spring loading of cylinder 431 returns piston rod 430 inwardly and retracts clamping bar 429 and roller 436 from their contact with the sleeve.
As is discussed above with reference to Figure 5, it is also possible to use a heated sealing bar 40 to form the seam of the blank. However, the embodiment just discussed utilizing the hot air system is preferred. The hot air system allows for heating smaller thicknesses of sheet blank since the hot air is directed between the overlapping end portions of the blank, and thus gives good heating effect to the areas of the end portions which are to be bonded. Using the heated bar 40, it is necessary to first heat the ou-ter overlaying portion and then the inner overlaying portion before a bond ~ - ~ ~
7~L5~

can be es-tablished. Thus, it will be appreciated that the use of a hot air system to simultaneously heat the juxtaposed por-tions of the blank simultaneously greatly reduces the time required to form the seam.
Sleeve Transfer System The seamed sleeve 117 is telescoped onto the forming mandrels 141 by a stripper mechanism, as discussed generally above, when the mandrels 131 and 141 are in register, i.e.
between about the 10 and 11 o'clock positions at the left-hand end turn of Figure 11. A stripper sleeve 138 is carried on each mandrel 131 and connected by a U-shaped arm 460 to an actuator rod 461, as can be best seen in Figure 14. Each rod 461 carries a roller 462 which rides on a continuous rising-falling cam plate 463 having a cam surface 463a. Cam plate 463 is mounted circumferentially on the frame 452 of the machine along the path of the mandrel movement by the ver-tical posts 464 and lateral brackets 4650 The rising portion of cam 463 occurs at the beginning of the ejection cycle and raises rod 461 to the position shown in phantom in Figure 14 to move sleeve 117 upwardly and off at mandrel 131 and over forming mandrel 141. The lower end of mandrels 141 are posi-tioned in close proximity to the upper ends of mandrels 131, and the lower ends of mandrels 141 are substantially smaller in diameter than the upper ends of mandrels 131 so that the sleeves 117 can be telescoped over mandrels 141 by mere verti-cal movement of the stripper sleeves, thus obviating the necessity of any complex sleeve gripping mechanisms. When stripper 138 reaches the end of its upward stroke, sleeve 117 is held by clamping ring 143 as can be best seen in Figures 22 and 26. Thereafter cam surface 463a falls to return stripper 138 to the retracted position shown in full lines in Figure 14.
Prior to the ejection cycle, each mandrel 131 is ~7~L5~4 rotated 180 by the rack and pinion system 42-6 so that the vertical vacuum ports 135 will be presented tangentially to the feed drum 420 as the mandrel and feed drum again approach the blank feed path, thus, resetting the mandrel for the next cyc]e.
Bottom Disc Cutting Station -The sleeve 117 and mandrel 141 continue through the arcuate travel of the left-hand end turn and then to the disc transfer station 600, whereat the bottom portion or disc 171 of the cup is deposited at the base of the mandrel 1~1. While the material for use in forming the discs 171 may be the same type used for the sleeve lI7, preferably, the discs are form-ed from other materials, e.g~ other thermoplastic materials, which are non-oriented and non-shrinkable, and have properties commensurate with the liquid tight sealing requirements of this invention.
Referring to Figures 11, 15 and 16, the bottom discs 171 used to form the base of the finished cup are cut, two at a time, from two continuous webs of thermoplastic material 501 20 The webs of bottom stock 501 are mounted on spools 501a with their axis of rotation perpendicular to the main conveyor 250.
The webs of bottom stock 501 are fed inwardly toward one another and over inclined rollers 502 which change the direc-tion of feed perpendicularly to the original direction, thus directing the webs of bottom web stock parallel to one another and into the disc cutting station 500.
Spools 501b are mounted in parallel coaxial relation ship with spools 501a and receive scrap bottom stock material from the disc cutting station 500, as will hereinafter appear.
Referring to Fi~ure 16, bottom web stocks 501 are pulled from right to left by unwinding rollers 510 and 511 (hereinafter described in detail) that are supported in spaced 5~
relationship with respect to cutting station 540. Web stocks 501 are unsupported between cutting station 540 and rollers 510, 511 and thus sag downwardly to form supply loops. Arcuate tracks 547a and 547b are positioned, respectively, adjacent the exit end of rollers 510, 511 and the entrance end of cut-ting station 540 and provide smooth guide surfaces which di-rect the web stocks into the cutting mechanism. The web stocks are intermittently pulled through the cutting station 540 by pull rollers 510' and 511' (also hereinafter described in detail3, and during the dwell periods of the intermittent feed, discs 117 are severed from the stock webs 501 by a reciprocating cutting mechanism, hereinafter described. The scrap webs that remain after the bottom discs have been severed are guided into the nip between rollers 510' and 511 by flat guide plates 547c, and the scrap webs then pass over further guide members 547d, rollers 502 and to the afore-mentioned spools 501b where the scrap material is accumulated.
After formation, bottom discs 171 are delivered to a linear conveyor 560 which conveys the bottom discs serially ~from right to left as viewed in Figure 11) to a disc transfer conveyor 600 which travels in a clockwise direction along a rectangular path to transport the discs to the main conveyor, where they are on the bottom of the forming mandrels 141.
Turning now to the web feed system, which can be best understood from Figures 16 and 19, independent lower unwinding rollers 511 are provided for each web 501, with rollers 511 each having integral opposite end shafts 511a and 511b which are supported in parallel vertical frame members 525 by bearings 520. ~n independent upper unwinding roller 30 510 is associated with each lower roller 511, and rollers 510 are also integrally formed with integral opposite end shafts 510a and 510b which are rotatably mounted in lever support -42~

3L~7~5~4 members 522 by bearings 523. Unwinding rollers 510 are smal-ler in width than rollers 511, as is clear from Figure 19.
Support members 522 are interconnected and pivotally supported in frame members 525 by shafts 526 that are spaced from and parallel with shafts 510a and 510b. Members 522 act as a lever and are free to pivot about shafts 526, so that the unwinding rollers 510 may be moved to a clearance position spaced from rollers 511 to facilitate initial threading of web stocks 501 into the feeding mechanism. Movement of members 10 522 is controlled by air cylinders 531 (Figure 19) connected at their head end to a transverse frame member 572 and con-nected at these rod ends to one of members 522. Upward move ment of members 522 is limited by stop studs 571 that are threaded into member 525 and which pass through enlarged clearance openings in members 522.
Each upper unwinding roller 510 is driven by its corresponding lower roller 511 through a gear system including gears 527 mounted on shafts 511a which mesh with gears 529 mounted on shafts 510a. Gears 529 are separated from bearings 20 523 by retainers 530, which position the bearings 523 in mem-ber 522, while gears 527 are retained in spaced relationship with respect to gears 570 on shafts 511 by spacers 52S.
The amount of unwound stock in the loop between the unwinding rollers 510 and 511 and the cutter section 540 is controlled by light sensors 535 that are mounted on opposite sides of the loop. The light sensors 535 are connected through appropriate circuitry (not shown) to electric clutches 519 connected to shaft 518, which is supported on the frame of the machine in parallel relationship below rollers 511, 30 and in a common plane with their associated shafts. Gears -517 are carried at opposite ends of shafts 518', which are operatively coupled -to shaft 518, and mesh with gears 570 -~3-~7~5~

that are fixed to the outer ends at shafts 511a for rotating lower rollers 511 when clutches 519 are energized.
Shaft 518 is continuously rotated by a drive means from a main crankshaft 541 (Figures 16 and 20) that is sup-ported in the frame of the machine in spaced parallel relation-ship with respect to shaft 518. Crankshaft 541 is driven by sprocket 544 by means of chain 543 that is connected to a suit prime mover, e.g., the prime mover for the main conveyor 250.
~ sprocket 542 is fixed on the end of the crankshaft 541 opposite from sprocket 544, and an endless chain 513 is trained over sprocket 542, and idler sprocket 514 and a sprocket 575 on shaft 515. Shaft 515 is mounted in spaced parallel relationship below shaft 518, and a transfer gear 512 on shaft 515 meshes with a gear 516 on shaft 518 to con-tinuously rotate shaft 518. Thus, as the stock webs 501 are fed through the cutter mechanism 540, the web loops being monitored by sensors 535 are raised until light is permitted to pass between the sensors thereby lnitiating rotation of the feed rolls 510, 511 through clutches 519 and the afore-described drive system to return the loops to their desired size.
The stock webs 501 are intermittently advanced through the cutter station 540 by means of rollers 510' and 511i which operate in a similar fashion to that of the un-winding rollers 510 and 511, except that the initial drive system is modified so that the rollers 510' and 511' are ro-tated continuously. Referring to Figures 16, 17 and 20, a gear 545 is mounted on the crankshaft 541 and meshes with a transfer gear 546 that is fixed on a shaft 546a, which is rotatably supported on the frame of the machine in spaced parallel relation above and to one side of crankshaft 541.

Transfer gear 546 in turn drives gear 547 which is mounted ~7~L5~L~
on the lower pull roller shaft 548, which, unlike the lower unwinding roller shafts extends through both lower pull rollers 511'. The remainder of the pull roller drive is similar to that of the unwinding rollers 510 and 511 and the elements are correspondingly numbered with prime numbers, and their opera-tion will not be repeated, except to note the structural change in the rollers.
As can be best seen in Figures 16 and 20, the upper pull rollers 510' are the same width as the lower rollers 511' and are mounted on separate coaxial shafts 551. The lower rollers 551' are circumferentially surfaced with a neoprene cover 549, that is formed with a high portion 549a and a dwell portion 549b. Rollers 510' have neoprene portions 550 bonded thereto. Neoprene portions 549a and 550 are positioned to engage the webs 501 simultaneously after the cutter mechanism 540 has moved out of engagement with the webs. The raised feed portions 549a and 550 have an arcuate extent that is coordina-ted with the diameter of the bottom d:iscs, so that each time the raised portions engage t~ ~s, the webs will be advanced a sufficient amount to place unsevered portions of the web stock above the cutting mechanism.
Discs 171 are severed from web stocks 501 by the cooperative action of movable cutters 561 and fixed dies 583.
Dies 583 (Figures 17 and 18) include a cylindrical central bore 583b, and cutters 561 are cylindrical in external configura-tion and guided within bores 583b. Dies 583 include horizon-tally aligned guide slots 583a at opposite sides thereof, and constrain the webs 501 for movement through the bore 583b of the dies. The external surface of each cutter 561 is posi-tioned in sliding surface abutting engagement with the inter-nal surface of a bore 583b, and the outer upwardly facing edge of cutters 561 cooperate with the inner downwardly facing edge ~715~L~

of die 583 above slots 583a to effect a shearing action upon the webs 501, when the cutters 561 are moved upwardly to, in effect, punch the discs from the webs.
Dies 583 are fixedly mounted upon a horizontally disposed frame member 584 (Figure 17) by bolts 583c, and frame member 584 is fixedly connected to vertically extending frame members 585 by bolts 584a.
Cutters 561 are moved vertically by a horizontally disposed platform member 561a, which is constrained for vertical movement by guide rods 587 (Figure 16) that extend downwardly from mounting member 584 and which are slidably mounted within guide sleeves 588 fixed to platform 561a. Each cutter 561 is carried by an upright post 561b that extends perpendicularly with respect to platform 561a. Upright posts 561b have an externally threaded lower end which projects beyond the lower surface of platform 561a, and an externally threaded collar 561c is threaded on the lower end of each post 561b to retain a downwardly facing shoulder 561d on each post against the upper surface of platform 561a. Cutters 561 include a bore 561e at the upper end thereof, and a counter-bore 561f at the lower end thereof which is received over a reduced diameter portion a-t the upper end of posts 561b, so that the cutters are seated upon an outwardly facing shoulder 561g on posts 561b. A hollow passage 561h is provided cen-trally of posts 561b throughout the length thereof, for recep-tion of a lifting rod to be hereafter described. The upper end of each passage 561h is internally threaded for reception of an externally threaded clamping screw 561i, which has an outwardly extending flange at the upper end thereof which bears against the end of cutter bore 561e to positively retain the cutters 561 against shoulders 561g.

Platform 561a is reciprocated by lin~s 580 having ~7~5~

bifurcated upper ends 580a pivotally connected to downwardly facing lugs 580b connected to the bottom surface of platform 561a at opposite sides thereof. The lower end of each link 580 is in the form of a split hub 581 that defines a journal for an eccentric that is fixed to shaft 541, it being under-stood that the throw of the eccentric is suf~icient to move the cutters from a clearance position disposed below the level of die slots 583a to an elevated position thereabove, as shown in Figure 18.
A lifter assembly is provided at cutting station 540 for transferring the cut discs to linear conveyor 560, and the lifter assembly includes connecting rods 562a mounted for vertical reciprocating movement ~ithin the passages 561h of posts 561b. Circular lifting discs 562 are connected to the upper ends of rods 562a by screws 562d that are threaded into countersunk openings in rods 562a. The outer diameter of lifters 562 is less than the inner diameter of cutter bores 561e so that the lifters can be nested therewithin during the web cutting operation. The lower ends of rods 562a are con-nected to a support member 562b, which in turn is connected to a mounting member 562c in the shape of an inverted U having the legs of the U slidably embracing crankshaft 5Al. A roller 563 extends laterally outwardly from member 562c and engages an eccentric cam 564 keyed to shaft 541, and cam 564 moves the lifters upwardly against a return spring 536 which is co-axially mounted on a vertical guide rod 586. Spring 536 reacts between frame member 584 and a spring seat on the upper sur-face support member 562b to bias the lifters 562 downwardly and to retain roller 563 against cam 564.
The eccentric cam 564, in one embodiment, has been formed with a 110 simple harmonic rise to move the lifters 562 upwardly in timed relationship with the upward movement of ~7~S~

cutters 561, it being understood that the throw of cam 564 is substantially in excess of the cutter eccentric, so that after discs have been punched from the webs and elevated slightly by cutters 561, lifters 562 move upwardly to raise the discs 171 above the upper surface of die 583 into a posi-tion to be transferred to linear conveyor 560. In the speci-fic embodiment mentioned in the preceding sentence, cam 564 has a 105 simple harmonic fall portion circumjacent to the rise portion for lowering lifters 562 into cutter bores 561e as the cutters are lowered toward the clearance position below the plane of the stock webs. Cam 564 has a 145 dwell portion to hold lifters 562 at an elevation below the plane of the stock webs, and while lifters 562 remain stationary, the cut-ter eccentric moves the upper edge of the cutters downwardly to the clearance position (at which time rollers 510', 511' advance webs 501) and then upwardly in a web severing stroke.
The lifters 562 are constrained for vertical move-ment by the slidable engagement between rods 562a and flanged rod bushing sleeves 561i and rod 586 which moves upwardly in 20 a guide opening 584c in plate 584.
In order to maintain proper tension in the webs 501 as they are fed and the discs 171 are cut thereErom, two spring loaded tensioner assemblies 566 are provided. The assemblies 566, one for each web 501, are biased to rotate counterclockwise (Figure 18) against the webs as they are con-veyed over member 547b. To facilitate the shearing action, the upper edge of cutters 561 may be inclined downwardly from diametrically opposed high points, so that the shearing takes place progressively as the cutters move through the web stock.
Initial Bottom Disc Conveyor The linear conveyor system 560 which moves the discs serially, parallel to the main conveyor to the disc transfer ~L~7~5~
conveyor 600 can be best understood from Figures 15 and 18.
As shown therein, conveyor 560 includes spaced parallel rails 565 that are essentially rectangular in cross section and which have recesses 565a on their oppositely facing interior faces.
The leading edges of rails 565 define an entrance width slightly less in width than the diameter of disc 171 but greater than the diameter of lifters 562. Since the discs 171 are made of a flexible thermoplastic material, as the lifters 562 move the discs upwardly, the outer edges of the discs will yield to allow the discs to be positioned in the recesses 565a.
Rails 565 are supported below parallel, coplanar, rectangular plates 578 by bolts 578a and spacers 578b, and plates 578 as suspended below fixed frame member 579c by bolts 579a that extend through transverse straps 579 and spacers 579b. A third, or central, rectangular plate 569 is mounted in spaced coplanar relationship between plates 578, bolts 589, and spacers 589a, and the edges of plates 579 and 578 form roller guides, as will hereinafter appear.
To insure that the discs 171 are not lifted past the recesses, stop members 567 are positioned directly above and in line with the center line of the lifters, and members 567 are free to move upwardly in the bore 567a of a guide sleeve 567b fixed to plate 569. A weight 537 is fixed to the upper end of each stop member to return them to their lowermost position. Discs 171 are supported on the lower flange of the recesses 565a, once the lifters 562 are retracted; and discs 171 are moved lengthwise along the rails 565 from right to left as viewed in Figure 15 to the disc transfer conveyor 600.
The conveyor 560 includes a pair of endless chains 576, the rollers of which move along the edges of guide members 569 and 578. Links 577a extend outwardly from chains 576, and carry downwardly extending pins 577 that are spaced in side by ~L137~5:~

side relationship with respect to one another by a distance less than the diameter of discs 171 when the pins 577 traverse the area between recesses 565a. Chains 576 are trained about idler sprockets 594 and 595 at the right hand end of plates 578, as viewed in Figure 15, and after the discs 171 have been positioned in recesses 565a and the lifter 562 retracted, the pins 577 contact the discs at their downstream portion and transfer them along the recesses 565a to the outlet ènd of linear conveyor 560.
Chains 576 are driven by sprockets 591 and 595 at the left hand end of plates 578, as viewed in Figure 15, with sprocket 591 being driven by a chain 590 from a sprocket 602' carried by a verti~al shaft 602a, which also drives conveyor 600. Tension is maintained in chain 590 by an idler sprocket 590b mounted on the end of an adjustable arm 590a. A spur gear 593a is mounted on shaft 592 and drives spur gear 593b, coaxially mounted with sprocket 595', to provide timed motion of the chains 576.
Final Bottom Disc Conveyor The conveyor 600 may be best understood from Figures 15 and 21 and is comprised of two vertically spaced endless chains 603a and 603b which are driven by a pair of vertically spaced sprockets (not shown) on shaft 602a below sprocket 602, and which are guided for movement around a rectangular path by pairs of vertically spaced idler sprockets 609, 611, and 612.
One side of the rectangular path of conveyor 600 is colinear with a portion (the outlet end) of conveyor 560, while the opposite side of the path of conveyor 600 is colinear with main conveyor 250.
A plurality of pick-up heads 601 are carried by chains 603a and 603b for picking up discs from linear conveyor 560, transporting the discs to main conveyor 250, and ~7~5~

serially transferring the discs to the bottom of forming mandrels 141. Pick-up heads 601 are each carried at the upper end of a vertically disposed carrier rod 605, and rods 605 are each slidably mounted within a vertical bore in a support mem-ber 604. Support members 604 have inwardly facing lugs 604a and 604b that are spaced by a distance corresponding to the spacing between chains 603a and 603b and rollers (not shown) are mounted in lugs 604a and 604b and are driven by chains 603a and 603b, respectively.
Support members 604 derive support from a fixed horizontal frame member 615 through track members 616 that are bolted to member 615 and which extend outwardly from the edges thereof. Track members 616 are provided with an upwardly fac-ing guide track 617 and an outwardly facing guide track 618 - -that receive, respectively, downwardly extending rollers 619 and inwardly extending rollers 620 on support members 604.
The structure of pick-up heads 601 can be best under-stood from a consideration of Figures 22 and 23. Pick-up -heads 601 include a horizontally disposed surface 601c adapted to support a disc 171 and surface 601c includes arcu-ate portions at the leading and trailing edges that are con-nected by generally straight side edges (Figures 23). A
flange 601a extends upwardly from the arcuate leading edge while a further flange 601b extends upwardly from the trailing edge. The diametric distance between flanges 601a and 601b is slightly in excess of the diameter of disc 171, which is shown in phantom in Figures 23. The trailing edge of the heads 601, including flange 601b, is shorter than the leading edge of the head and flange 601a to thereby provide access openings 601d at the trailing edge of the pick-up member to accommodate pins 577, as will hereinafter appear. Flanges 601a and 601b co-operate with surface 601c to collectively define a generally ~7~5~

cup~shaped receptacle for holding discs 171.
Pick-up members 601 have a central vertical bore 601e (Figure 22) having a bushing therein, that is received over a reduced diameter upper end of carrier rod 605. A re-tainer ring 605a is fitted on the upwardly facing shoulder on rod 605 at the lower,end of the reduced diameter portion, and a spring 608 extends between ring 605a and a downwardly facing shoulder 601f on each pick-up head to bias the pick-up heads upwardly. An enlarged flange 605b is provided at the upper 10 end of each rod 605 to retain the pick-up members 601 thereon.
A cam track 606 is mounted on the machine frame in the colinear area of conveyors 560 and 600, and cam track 606 includes a rise portion that is aligned with discs 171 and heads 601 as they pass through the colinear area. Shaft 605 is provided with a roller 607 at its bottom portion which engages the cam 606, and the rise portion of the cam causes the head 601 to be moved vertically upward to receive the disc 171, the head being returned to its lower position by cam 606 after disc 171 has been received.
Chains 603a and 603b move the raised heads 601 into vertical registry beneath the discs 171 and as the individual discs 171 approach the ends of guide rails 565, the pins 577 push the discs off of tracks 565 and the discs fall so that the leading edge of the disc initially engages the leading flange 601a of the head 601 and then the entire disc falls so that the trailing end of the disc is adjacent flange 601d. As the discs are transferred to the heads 161 they remain under the control of pins 577, which are nested within recesses 601d at the point of transfer. The trailing portion 601b of the head is provided with recesses which accommodate the fingers 577 as a disc 171 is being transferred from the rails to the head during register movement.

~i7~5~

After the disc 171 has been received in the recess of the head 601, the disc transfer conveyor 600 moves the heads 601 into the colinear~ area between conveyors 600 and 250 and into vertical registry with the main conveyor forming mandrels 141. A cam 613 is mounted on the frame of the machine in the colinear area between conveyors 600 and 250, and in-cludes a rise portion aligned with mandrels 141 as they pass through a colinear area. Roller 607 rides within cam 613 to lift the disc carrying head into the disc transfer position shown in Figure 21 in contact with the bottom of mandrel 141. -The head 601 and mandrel 141 move together while in contact, and the bottom disc 171 is transferred to the bottom of the mandrel by means of a vacuum applied to the bottom of the man-drel. The spring 608 cooperates with the camming action to insure a close union between the head 601 and the mandrel 141 during disc transfer.
A pair of vertically spaced tubular vacuum reser-voirs 210 and 220 (Figure 21) are supported on the frame of the machine above the colinear sections of conveyors 250 and 600, and reservoir 220 extends from the colinear conveyor sec-tions essentially through the entire shrink tunnel 600, to be hereinafter described, while reservoir 210 extends only par-tially through the shrink tunnel. Reservoirs 210 and 220 are connected to a suitable vacuum source (not shown) and are connected, respectively, through elongat~d slots 211 and 221 with fittings 212 and 222 that extend outwardly from the man-drel support members 252. Fittings 212 and 222 are connected, respectively, to vertical passages 145 and 146 (Figures 21 and 26) that extend the entire length of the spindle portion 147 of support member 252. A lateral port 146a (Figure 26) establishes communication between passage 146 and the space between spindle 147 and the contoured sidewall at the lower -\
~7~5~4 end of spindle 141. A plurality of passages 141b are provided in the mandrel sidewall for applying vacuum to the sleeve 118, in the shrink tunnel as will hereinafter appear.
A plug 142 is seated within a downwardly opening recess 143 in the lower end of mandrel 141 and plug 142 ;n-cludes a passage 142a establishing communication between pas-sage 145 and a plurality of fine vertical passages 144 spaced circumferentially around the plug adjacent the outer diameter thereof. Plug 142 includes a further passage 142b that establishes communication between passage 146 and a plurality of spaced vertical passages 253 in the upwardly dished central portion of plug 142. Passages 253 are somewhat larger than passages 144 to assist in shaping the bottom contour of the cup, as will hereinafter appear. The vacuum drawn through passages 144 applies retentive force to the edges of disc 171, and positively holds the disc on mandrel 141 as head 601 is cammed downward by cam 613.
Shrink Tunnel Immediately upon receiving the bottom disc 171, the forming mandrels 141 are conveyed through a shrink-tunnel or oven wherein the thermoplastic material is caused to shrink to the contour of the surface of the forming mandrel 141.
Referring to Figures 11 and 30, the shrink-tunnel 700 includes six longitudinally extending infra-red heaters which are dis-posed, respectively, along the inside (701a and 702a), out-side (701b and 702b), and beneath (703) the path of conveyor 250.
Side heaters 701a and 701b are parallel to the side of the path of the main conveyor 250 at the first half of the shrink tunnel, with the mandrel facing surfaces of the heaters being parallel to one another, to uniformly heat the generally cylindrically shaped sleeve 117 and initially heat the slee~es ~7~LS~

as they move into the shrink tunnel. As sleeve 117 is heated by heaters 701a and 701b, the lower end portion of the sleeve moves away from each of the heaters inwardly toward the small contoured end of the mandrel 141 so that the upper portion of the sleeve would be heated to a greater extent than the lower portion. As noted above, the taper of the sleeve ranges from 5-7 at the top thereof and increases to a taper on the order of at least 15 at the bottom. To accommodate for this dif-ference in distance and provide for generally uniform heating, heaters 702a and 702b are canted to assume a position substan-tially parallel to the mean contour of the forming mandrel 141 so that the distance between the heating elements and sleeve 117 is substantially equal along the second half of the shrink tunnel.
In one shrink tunnel embodiment, good results have been achieved by canting heaters 702a and 702b at an angle of 7-1/2 from the vertical plane. In this embodiment, the heat-ing elements of each canted heater were spaced a perpendicular distance from the stacking shoulder contour on the mandrel 141 substantially equal to the perpendicular spacing of the up-stream heaters from the path of conveyor 250. In this embodi-ment, the upstream bottom heaters were spaced approximately

2 inches lower than the downstream bottom heaters so that the lower portion of the sleeve is not heated sufficiently in the first half of the shrink tunnel to produce premature curling or folding of the sleeve.
The heaters are mounted on an elevator assembly 740 which raises the heaters from a lowered position to an ele-vated operating position (shown in phantom in Figure 30) around conveyor path 250 by means of two air cylinders 794 (only one of which is shown in Figure 30). The heaters are thus adjustable to allow for service of the mandrels in the ~a37~s~4 shrink oven and to provide for start-up and shut-down of the machine.
The heaters are adjustably mounted by two indepen-dent but interconnected mounting assemblies 750. Each assembly 750 includes two L-shaped brackets 751 which mount the ends of each of the side heaters to corresponding sets of inver-ted L-shaped adjustment brackets 752, by bolts 753. Side heaters 701a, 701b, 702a and 702b are secured to their respective brackets 751, as by welding. Brackets 752 are provided with horizontal adjustment slots through which bolts 753 pass so that each side heater may be independently adjusted inwardly and outwardly relative to the mandrel path. Spacers 753a, such as a shim material, may be positioned between the abutting horizontal surfaces of brackets 751 and 752 to provide the desired cant to side heaters 702a and 702b.
Each vertical adjustment bracket 752 has a side plate 752a in abutting relationship to a mounting plate 754, and parallel vertical slots 752b inside plates 752a are each impaled by a bolt 755 to guide brackets 752 for vertical move-20 ment relative to plates 754. Brackets 752 are moved by verti-cal adjustment studs 756, the upper ends of which bear against the lower surface of blocks 757 fixed to the lower portion of side plates 752a. The midportion of each stud 756 is threaded through a block 758 on the vertical surface of plate 754 so that, as each stud 756 is turned, the elevation of heater end thereabove is adjusted.
A longitudinally extending U-shaped channel 760 is centrally located between the brackets 752 of each pair of side heaters, and each channel 760 carries a bot-tom heater 30 703. The bottom heaters 703 are located centrally between the upwardly extending legs of channels 760, and to this end, L-shaped adjustment brackets 761 are secured to the ends of

3 ~7~
channels 760 by bolts 762 that extend through vertical adjust-ment slots in the vertical portion of bracket 761. The base of each channel 760 is secured to mounting pads 771 at each end by bolts 770, and the mounting pads are in turn fixedly mounted on an inverted U-shaped channel member 772 which ex-tends the full length of the shrink tunnel to provide for con-joint movement of the assemblies 750, as discussed below.
Vertical studs 775 are provided for independently adjusting the elevation of bottom heaters 703, and studs 775 are threaded through pads 771 and pass through clearance holes in channels 772 and 760 to bear against adjustment blocks 776 located on the bottom surface of bracket 761 to provide means for adjust-ing the end of the bottom heaters independently of each other and the side heaters.
The mounting assemblies 750 are positioned between and bear against parallel, vertically extending frame uprights 780 through lever mounted roller assemblies 781 which are provided at each side of opposite ends of channel member 772.
Each roller assembly includes a pivot block 782 fixedly -attached, as by welding, to the bottom surface of the web of channel 772, and a lever 783, pivotally attached to one of blocks 782 by pin 784. Each lever member carries a lateral roller 786 which bears against an upright 780 under the in-fluence of loading spring 785 disposed upwardly from each lever member to contact the lower surface of the web of channel 772. Each loading spring is adjustable by bolt 785a so that the moment and bearing force generated in each roller against upright 780 may be adjusted. The frame uprights are supported by longitudinal channels 787 at the base and top, and the bottom flanges of the base channels are mounted on floor pads 788.
The channel 772 is supported by an air cylinder r ~ D7~5~1 activated linkage system 799 at each end of the shrink tunnel, and each system includes a connection link 790 mounted to the lower surface of the web of channel 772, a first pair of paral-lel links 791 pivotally connected at one end to link 790, a second pair of parallel links 792 pivotally attached outboard the ends of links 791, a base link 793 mounted to floor pad 788 and pivotally attached at the other end to links 792.
Each linkage system is operated by an air cylinder 794 which is pivotally mounted (not shown) at an angle with respect to base 788. The piston rod 795 of each cylinder is pivotally attached to the linkage system inboard at the joint of links 791 and 792, so that, as the rod 795 is moved outwardly of the cylinder, the linkage system will raise the heaters to the operative position shown in phantom line in Figure 30.
Shrink tunnel 700 is provided with means for rotat-ing the forming mandrels 141 to assure even distribution of heating. To this end, the edge portion of a horizontal rail 711 engages within recess 251 of the forming mandrel, so that as the mandrel is conveyed through the shrink tunnel the man-drel will rotate about its spindle 1470 Rail 711 is prefer-ably formed of a resilient material so that contact is main-tained with recess 251. Rail 711 is suspended below frame member 229 from inverted L-shaped brackets 722 by studs 712 and nuts 713, and preferably is coextensive in length with the shrink tunnel.
As the sleeve 117 is being shrunk in the tunnel, the vacuum that is supplied along the contoured surface of the mandrel cooperates with the shrinkage attributable to the heat to cause the sleeve 117 to closely conform to the external contour of the mandrel. As the sleeve 117 shrinks, the lower portion thereof moves inwardly into overlapping rela-tionship with the peripheral edge of the bottom disc 171, while the ~L~7 IL5 iL~

central portion of the disc is drawn upwardly by the combined action of the heat and the vacuum applied through passages 253.
Alternately, the shrink tunnel may also be formed with two sets of heaters disposed to one side and beneath the path of the conveyor 250. Referring to Figure 24, the shrink tunnel 700' includes longitudinally extending infra-red heaters 701' and 702' which are disposed, respectively, along one side and beneath the path of the conveyor 250. Reflector plates 703' located opposite heater 701' and reflector plates 704' located above heater 701' are designed to contain and reflect the infra-red heating rays emitted from the heaters. Reflec-tor plates 704' are mounted to a frame member 720' by insula-tors 705' which are secured to frame brackets 719' by bolts 706'. Reflector plates 703' are mounted to vertical support member 707' by insulators 708' and bolts 709'. The apparatus for rotating the mandrels 141 and supplying vacuum thereto are the same as shown in Figure 30 and are correspondingly numbered.
Bottom Forming Station Referring to Figure 11, after the sleeve 117 has been shrunken to the contour of the forming mandrel 141, the mandrels are conveyed to the bottom forming station 800 at the right-hand turn of the main conveyor where the bottom disc 171 and sleeve 117 are joined to provide a liquid-tight seal.
The seal between the overlapping edge portion 117b of the sleeve and the peripheral edge of the disc 171 is ef-fected by a heated die 801, as shown in Figures 25 and 25a.
Dies 801 are mounted for vertical movement relative to a hori-zontal turret 802 that is connected for rotation with shaft 30 810 by a key 811. To this end, a plurality of vertical die support posts 803 are mounted for vertical movement within sleeves 821 that are secured at circumferentially spaced 3LC~7~5~
positions around turret 802. Sleeves 821 are located on a common diameter, and in vertical registry, with mandrels 141 when the mandrels move into the bottom forming station.
A cam track 804 is secured to frame structure 822, and a cam 804a is secured to the lower end of rod 803 and engages cam track 804. Cam track 804 has a rise portion which moves the heat~d dies 801 upwardly into engagement with in-wardly extending sidewall portions 117b as the mandrels 141 traverse the right-hand end turn of the main conveyor.
Each die 801 is spring biased upwardly by a spring 820 that extends between an annular spring retainer 825 fixed to rod 803 and a spring seat in the lower portion of the die.
A guide pin 826 is fixed to retainer 825 and is slidably re~
ceived within a downwardly opening passage 827 in the die to assist in guiding the die for vertical movement relative to the retainer 82S.
Die 801 consists of a heater element 828 and a sealing head 829 that is secured to the upper surface of heater 828. The heater 828 includes a central bore that is slidably positioned over the upper end of rod 803, and which is re-tained thereon by an adjustment nut 830 that is connected to the upper end of rod 803.
Sealing head 829 includes an outer annular ring 831 having a plurality of pairs of diametrically opposed radial passages 832, as can be best seen in Figure 25a. A forminy member 833 is positioned centrally of ring 829, and is floatingly mounted and centered relative thereto by springs 834 that are received in passages 832. Springs 834 react - -between set screws 835 threaded into the outer ends of pass-ages 832 and the outer sidewall of forming member 833 to resiliently maintain the forming member in a centered posi- ~;

tion. The inner end of springs 835 are retained by flanges ' ~L~7~5~4 836 and 837 on opposite sides of the forming member 833.
The forming member 833 is provided with an upwardly facing generally frusto-conically shaped recess 838 which has a contour which conforms with the desired final configuration of the lower portion of the cup. A plurality of upwardly extending annular ribs 839 are provided on the base of recess 838 to provide corresponding annular rings in the bottom por-tion of the formed container.
Forming member 833 is heated by conduction through heater 828, which in the illustrated embodiment is an electric heating element that is powered by wires 818 which extend through the center of shaft 810, and contact brushes 819 to -receive electrical power. As a result of the heat and pres-sure caused by the aforedescribed die 801, a liquid-tight seal is produced between the bottom disc 171 and the inwardly extending lower portion 117b of the sleeve.
As each mandrel 141 and die 801 approach the end of the right-hand turn, the die is cammed downwardly out of con-tact with the mandrel 141, and the mandrels proceed to the rim forming station 900.
Rim Forming Station After the sleeves 117 have passed through the bottom forming station, they are complete except for the formation of the curled top rim. The details of the specific rimming mechanism that is utilized at the rimming station is not critical to the present invention and several techniques known to those skilled in the art may be employed. One such tech-nique will be described generally herein.
A separate conveyor is provided at the rimming sta-tion, as is evident from Figure 11. The mechanism for eject-ing the non-rimmed cups from the main conveyor 250 and depositing the cups on the rimming conveyor can be best under-7~5~.~
stood from Figures 26 and 27. As shown therein, a cup ejector mechanism 910 is mounted adjacent -the path of travel of main conveyor 250 and includes an ejector member 911 that is mov-able downwardly into engagement with sleeve 277 to strip the non-rimmed cup from the forming mandrel 141. Member 911 is in the form of a roller that is carried at the outer eccentric end 912 of a shaft 913 that is rotatably mounted in a bearing block 914. A right angle gear box 915 is supported from the frame of the machine by a bracket 916 and rotates shaft 913 from a sprocket 917. Sprocket 917 is driven from a chain 918 and a drive sprocket 919 that is synchronized with the drive to the rimming conveyor.
The rimming conveyor includes a plurality of spaced cup holders 920 (Figure 21) that are advanced into vertical registry with the mandrels 141 as the shaft 913 rotates roller 911 into engagement with the upper su:rface 277a of sleeve 277.
Sleeve 277 moves downwardly and the lower surface 277b there-of lowers clamping ring 143 to a reduced diameter portion of the mandrel to release the sleeve. Surface 277b then engages the upper edge of the cup sidewall to positively strip the container from the mandrel 141. Positive pressure may be applied through passages 145, 146, 141b,144 and 253, to assist in freeing the container from the mandrel, if desired.
Cup holders 920 are conveyed at the same linear speed as mandrels 141, and are positioned in close vertical proximity to the bottom of the mandrels so that the stripped cups fall downwardly directed into the holders. Holders 920 have a frusto-conically shaped interior which supports the upper edge of the cup in a position to be rimmed. The rimming conveyor then transports the holders 920 past a rimming die 922, and relative movement is effected between the rimming die 922 and the holder 920 to form a curl at the upper edge of the ~7~5~

sidewall of the cup. The process of the present invention is then completed by removing the rimmed containers from the rim-ming conveyor, and this can be accomplished by conventional techniques not important to the present invention.
The invention, and operative embodiments thereof, have been described above in terms sufficiently full, clear, concise and exact as to enable any person skilled in the art to make and use the same. It is to be understood, however, that it is within our contemplation that certain modifications of the above-described mode of practicing the invention can be made by a skilled artisan without departing from the scope of the invention and it is, therefore, desired to limit the invention only in accordance with the appended claims.

Claims (15)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of forming a cylindrical sleeve from a sheet of thermoplastic material comprising the steps of forming said sheet into a generally tubular shape around a cylindrical support with one end portion of the sheet overlapping the other end portion, pressing said one end portion into gripping contact against said support transversely of said one end portion inwardly of its outer free edge, establishing a separation between said sheet overlapping end portions by directing a stream of hot air from a duct toward said gripping contact into the space between said overlapping end portions while maintaining the sheet in a fixed relationship to said duct, continuing the flow of hot air into a V-shaped pocket formed between said separated end portions to cause the thermoplastics material of said separated end portions to soften, diverting the stream of air away from said end portions after they become softened, and pressing together the softened material of the overlapping portions to form a seam.

2. A method as claimed in claim 1 wherein said tubular shape is formed by holding the edge portion of the other of said end portions in contact with said cylindrical support and wrapping said sheet around said support by rotating the support.

3. A method as claimed in claim 2, wherein said overlapping one end portion is held in gripping contact by pressing a roller into engagement with the exterior of said sheet as said support is rotated

4. A method as claimed in any one of claims 1, 2 or 3, wherein said hot air is at a temperature in the range 550°F to 650°F.

5. The method of forming a rectangular sheet of thermoplastic material into a sleeve comprising the steps of:
forming said sheet into a generally tubular shape with one end portion of the sheet overlapping the other end portion; gripping said one end portion inwardly of the free edge thereof; directing air from a heating means toward the overlapping end portion; along the extent thereof while maintaining said sheet in a fixed position relative to said heating means, to cause the overlapping end portions to separate and form a V-shaped pocket against the flow of air, whereby said air simultaneously softens the facing surfaces of both of said end portions; diverting the flow of air away from said overlapping end portions after said facing surfaces are softened; and pressing the one overlapping end portion against the other end portion to compress said softened surfaces to form a liquid-tight seam.

6. The method according to claim 5 wherein said forming step is performed by wrapping said sheet around a cylindrical-shaped support by rotating said support.

7. The method according to claim 6 wherein said wrapping step is preceded by the step of gripping said other end portion against said support close to the edge thereof.

8. The method of forming a rectangular sheet of thermo-plastic material into a sleeve comprising the steps of: attaching the leading end of said sheet at the edge thereof to a cylindrically shaped support, wrapping said sheet about said cylindrically shaped support by rotating said support to form said sheet into a generally tubular shape with the trailing end portion overlapping the leading end portion; gripping said trailing end portion inwardly of the free edge thereof; directing air from a heating means toward the overlapping end portions along the extent thereof while maintaining said sheet in a fixed position relative to said heating means, to cause the overlapping end portions to separate and form a V-shaped pocket against the flow of air, whereby said air softens the facing surfaces of said end portions; diverting said air away from said end portion after said facing surfaces are softened; and pressing said trailing end portion against said leading end portion to compress said softened surfaces to form a seam.

9. The method according to claim 8 wherein said air directing step is performed by forcing heated air through a converging nozzle.

10. Apparatus for forming a cylindrical sleeve from a sheet of thermoplastics material comprising a cylindrical mandrel supported for rotation about its longitudinal axis, means for rotating said mandrel, means on said mandrel for holding one end portion of the sheet in contact with said mandrel to cause a sheet longer than the circumference of said mandrel to be wrapped around the rotating mandrel with the other end portion of said sheet in an overlapping relation to said one end portion, means pressing said other sheet end portion into gripping engagement against said mandrel a short distance inwardly from its outer free edge, a duet connected to a supply of hot air having an outlet adjacent said mandrel and positioned to direct the hot air flow from the outlet into a V-shaped pocket formed between the facing surfaces of said overlapped sheet end portions by the pressure of the air flow of which the heat softens said overlapping end portions, a sealing bar extending longitudinally of said mandrel supported for movement between a position retracted from the sheet and an extended position in pressing engagement with the overlapping sheet end portions, means for diverting the hot air away from the overlapping sheet end portions after the material thereof becomes softened, and means for moving said sealing bar from said retracted to said extended position after hot air has been diverted away from the sheet overlapping end portions to sealingly press the end portions together.

11. Apparatus as claimed in claim 10, wherein said duct has a second opening facing away from said mandrel, a cover movably positionable over said opening and means operable to move said cover selectively between positions closing and uncovering said opening such that said cover is moved to said uncovered position after it has been in a covered position a sufficient time for the sheet material to become softened to divert hot air away from said softened overlapping end portions.

12.Apparatus as claimed in claim 11, wherein said cover has a pivotal connection to said duct adjacent said opening and said operable means of movement comprise a vertical link connected at its lower end to a camming assembly operable to raise and lower said link in a predetermined pattern, a slide pin assembly slidably and pivotally connecting an outer end of said cover to an upper portion of said link, an adjusting collar threadably connected to said link above said slide pin assembly, and means biasing said slide pin assembly upwardly against said adjusting collar, whereby the length of time said cover is in the closed position may be adjusted.

13. Apparatus as claimed in claim 12, wherein biasing means normally biases said vertical link downwardly to move he cover into an uncovered position and said camming assembly comprises a pivotally mounted lever pivotally connected at one end to the lower end of said vertical link and having a cam follower at the other end thereof and a cam engaging said cam follower for effecting continuously rising and following movement of said cam follower to move said link vertically and move said cover toward a closed position.

14. Apparatus as claimed in claim 10, wherein said other sheet end portion holding means comprises a roller supported for movement between a retracted position spaced from said mandrel and an extended position in contact with said sheet other end portion a short distance from its outer edge and spaced from said sealing bar in the direction of said mandrel rotation.

15. Apparatus as claimed in claim 14, wherein said sealing bar and roller are each mounted in juxtaposition on a support member movably radially of said mandrel, said roller being supported on said support member for movement relative thereto and biased normally to project toward said mandrel ahead of said sealing bar into contact with the sheet on said mandrel when said sealing bar is in the retracted position, said support member being movable between positions in which: (a) both said roller and said sealing bar are retracted from contact with the sheet, (b) said roller is in contact with and said sealing bar is out of contact with the sheet and (c) both said roller and said sealing bar are in contact with the sheet.