SE433921B - Integral vessel and method for its manufacture - Google Patents

Abstract

A vessel manufactured from one single piece of sheet-shaped light plastic material. A simple method for manufacturing an integral vessel from sheet-shaped light plastic material. The method comprises providing a vessel blank of sheet material, forming a cylinder and through controlled heat-shrinking forming a cup blank which is pressed into a final form.

Description

7806207-2 10 20 30 35 2 of a container, after the coat has been removed and the edge has been rolled. Fig. 6 is a view of a mandrel with one thereon laid cylindrical sleeve. Fig. 7 is a view of the mandrel with a container shell formed thereon. Fig. 8 is a sectional view of matched molded parts for molding the container to the final form. Fig. 9 is a side view of a stock of stacked containers.

The present invention utilizes a foam field material, such as polystyrene or polyethylene or the like. Arkma- the material is preferably prepared by foam spraying.

The foam field is subjected to orientation in one or both directions the ings. The orientation in the foam market enables control line forming of the container during its manufacture. t A container blank has the reference numeral 10 in FIG 1. The substance has been cut so that it is in the form of a tangel. Although the rectangle shape is highly desirable, can the substance l0 also be square and still give the benefits of finding. The blank 10 has been removed from one larger piece of foamed sheet material by conventional cutting technology. The blank l0 has been cut so that the sheet material the maximum orientation of the material coincides with that of the substance 10 longitudinal direction. Ends 12 and 13 represent the substance 10 short pages. It is possible to use such sheet material, which has a degree of orientation perpendicular to the direction for the maximum orientation. The degree of orientation * perpendicular to the maximum length of the substance 10 should be be close to zero. Although the substance 10 does not exhibit any decoration on the drawing, it can easily be imagined that the substance 10 can be decorated, while it is in a flat stand. ' Fig. 2 shows a cylinder 14 which has been provided by the blank 10. the direction of travel of the cylinder 14 is biiaaa 'of the substance's 10 largest extent. Ends l2 and 13 of the blank 10 are provided with overlap; as shown at 15 on the cylinder 14. The ends 12 and 13 can be stapled at each other by applying an adhesive layer on at one or both ends. The ends 12 and l3 can.also 10 15 20 25 30 35 7806207-2 3 connected by heat softening and then compression of the surfaces of the adjacent ends. Heat can be supplied in any conventional form, e.g. energy, from heated plates or as hot fluids there, eg air. The overlap of the ends can be maintained a minimum of 4 or 5 times the material thickness, however the best results are obtained if the overlap of the ends 12 and 13 are in the range of 15-20 times that of the sheet material thickness.

Fig. 3 shows a preformed container shell 16. The cylindrical the risk shell 14 is placed over a mandrel, the turn close resembles the inside of the finished container. Dor- nen is substantially truncated conical and consists suitably of metal, although other materials may work just as well.

After the application of the cylindrical shell 14 over the mandrel, the whole unit is exposed to a hot fluid bath.

Although the fluid bath may be liquid, air is preferred the heat exchange medium. The mandrel and sleeve 14 remain underneath the influence of hot fluid bath for a predetermined length time. Depending on the physical foam used properties, the time in the fluid bath can vary from 1 second to 15 seconds. As soon as the foam material reaches one critical temperature, eg 130 ° C for polystyrene, begins the individual cells in the foam or cell structure to regain its original spherical shape. Consequently shrinks the cell material in the direction of original de- formation or orientation. Because the sheet material was oriented predominantly along the rectangular length of the blank 10, the shrinkage is also in the same direction.

The cylindrical sleeve 14 shrinks in the circumferential direction in the areas not hindered by the mandrel. Part of the the sleeve 14 projects over the mandrel and is not obstructed of the mandrel, when heat is applied to the sleeve 14. The neck 17 on the shell 16 arises because it does not exist any obstruction from the mandrel during the heating cycle. Total- the thickness of the neck 17 and adjacent areas, including pande a part of the shell 16 truncated conical side wall, is 10 15 20 25 30 35 7806207-2 4 thicker than the original sheet material.

Fig. 4 shows the truncated conical shell 16, then the neck 17 has been shrunk or stapled near the bottom 19. The neck 17 can be closed by lateral movement. work tools or can be carried by separate rolls. The tools can be heated for machining the plastic material, or the folding action may be follow the shrinkage cycle, which has been described in band with fig 3. the folding action produces a thin line 20 of material between the jacket 18 and the container bottom nen l9. A slight lateral force completely releases the coat l8 from the container bottom l9. The jacket 18 is removed best since the plastic material has reached ambient temperature ratur. After the jacket 18 has been removed from the container bottom 19 remains somewhat container bottom 19. It is possible that but this material, projecting from the plane I flattens the protruding material, is not so desirable from the point of view of materials that are compressed too much have a tendency to become less opaque and more transparent. About the rest of the coat is leveled to, the center of the finished container will added part to look like it had a hole in it, or the transparent area is taken for contamination with e.g. oil or fat.

Fig. 5 shows a finished beaker 21. The beaker Z1 has one support member or bottom area 22 and a rolled or folded weight edge 25. The bottom area 22 contains a central imprint sat flat area 23. The middle part of this area contains the cutting point 24, where the coat 18 was once attached. As mentioned earlier, it is desirable that the cutting site 24 be shoots from the bottom of the container, in order to eliminate it unpleasant optical spot in the center of the beaker or the holder. The depressed area 23 and the edge 25 are formed 16 1 a set of matcha- the mold parts. The placement of the shell 16 in these mold parts .also has an additional advantage in that the side wall of the container can be made uniformly thick from top to bottom by placing the shell lO 1.5 20 25 30 35 7806207-2 5 the bottom. The thickness of the side wall of the shell 16 is greater in near the bottom than near the top or the edge 25. The extra thickness of the side wall prevents the laying edge to edge of the finished containers 21. Se- the side wall has been reduced to a uniform thickness by means of the matched mold parts, the containers 21 can be read tightly edge to edge. This feature enables trans- port of more containers per unit volume.

In carrying out the method according to the invention, a mandrel 30 shown in Fig. 6 has a mandrel 30 conical top section 31 with an outer surface 32. This surface veneer very close to the inner geometry of the container. The The conical section 31 is mounted on a lower support plate 52 by means of any conventional mounting device, not shown gan. The plate 52 may, of course, be part of a transport system, if desired. A cylindrical substance 14 are shown in broken lines to illustrate the action between the mandrel 30 and the cylindrical blank 14.

Fig. 7 shows a shrunken shell 16, as it appears on the mandrel 30. The neck 17 has been reduced to a minimum diameter, but its opening is not closed. In order to facilitate complete closure of the bottom is tubular slopes 33 and 34 arranged radially from the outer surface of the neck 17. The jaws 33 and 34 may be two or more and are mounted (not shown) for movement against each other along paths, which are radial to the neck 17. The slopes 33 and 34 can be heated or they can cooperate with the neck 17 while this is in a warm, softened state to as a result of the shrinkage operation. Slopes 33 and 34 pipes to and from engagement with the neck l7 for achieving of a closure of the container bottom, as shown in Fig. 4. The shell 16 is then allowed to cool so that it attaches the jacket 18 can be broken off. It is possible that some plastic materials are not broken as suitably as, for example, polystyrene, why the slopes 33 and 34 can be provided with means for coming of a cutting operation on the coat, so that the coat can be removed before cooling. 7806207-2 lO l5 20 25 35 6 Fig. 8 shows a set of matched mold parts 35 and 36. A female mold part 35 has a groove 51 which is angular. straight against and concentric with the axis of symmetry of the molds. the groove 51 is by means of an inclined truncated conical section 39 connected with a land party 37. The land party 37 is also concentric with the axis of symmetry. the transition from the groove 51 to the land portion 37 is preferably gradual because the container may crack if the edges of the mold part are too sharp. The central part 38 of the female mold part 35 is formed with the same release as the groove 51. It central part 38 offers sufficient space for the cutting stub or cutting point 24. The male mold part 36 contains holds a bead forming groove 40 at its lower part. Top- the part of the male form part has a raised land portion 41, which cooperates with the groove 51 in the female mold part 35. The central the area 42 at the male mold part 36 receives the bottom of the container. when it is deformed by the land portion 37 on the female mold part 35.

For operation, a preformed container shell 16 is placed on the male mold part and the female mold part is lowered over the cup.

After closing the mold parts 35 and 36 in the largest possible way one to a stable, flat bottom ring 22 is present. The bottom ring to a large extent, the container is removed. The container then has bead 25 and a bottom, which is pressed in the middle, so 22 allows the container to be filled with liquid and the container the reindeer will still rest firmly on their bottom ring 22 without spillage of the contents of the container.

Another important feature of the mold parts in Fig. 8 is that they equalize the total wall thickness of the container.

Any local blistering or uneven expansion or contraction of the side wall of the container is eliminated or reduced to such a level that the stacking of containers can be performed in full. They matched form- the parts in Fig. 8 enable the production of such a holder, where the side wall has a uniform thickness but the density of the sidewall material varies in proportion to the diameter of the container. The container has a larger seal. 10 15 20 25 30 35 7806207-2 7 near the bottom side wall than at the top side road gene, as more material is present in this area due to the shrinkage from the original cylinder risk form.

It has proved advantageous to place the pre- made the container shells 16, from which the caps 18 have in the mold parts 35 and 36 after the container has been the temperature of the shell has returned to ambient the tour. The container 21 in Fig. 5 will hold a liquid and act as a cup before being subjected to parts 35 and 36. The beaker receives during the treatment with and 36 an edge 25, a submerged bottom circumference area 23 and side walls of uniform thickness. the mold parts 35 Fig. 9 shows a stack of stacked containers.

The edges 25 of each container can be placed so that they are next to each other. The containers 21 can be removed from the stand. peln when desired, without requiring any major force to distinguish one cup from another. Featured with stacking edge to edge yields several cups per predetermined stacking height, so that the transport space is reduced and more beakers can be fed into an automatic filling device ning. The feature of edge-to-edge stacking is veter- new in containers, such as drinking cups, made of foam material.

The way to expose an almost finished container to one dimensioning effect from matched molded parts is a essential feature of the present invention. The treatment of the container by means of matched mold parts 35 and 36 can is considered to be a deep-drawing process, where the container side is made uniform in thickness, so that a denser stack of the cups is made possible.

At the known containers one encounters difficulties when removing individual containers from a stack of interconnected containers. The problem had its hoof in an increase in the container wall thickness towards the bottom of the container. The increased thickness is inherent characteristics of containers made of oriented foam market 7806207-2 8 material, as the material increases in thickness in the areas, where the greatest shrinkage occurs.

Claims (2)

A one-piece container made of sheet-like foam material, the side wall of the container (21) at the top ending with a bead edge (25) and at the lower end with a closed bottom (22, 23), which side wall has at least one overlapping seam extending from the edge to the bottom and a uniform thickness from top to bottom with varying density from a minimum at the top to a maximum at the bottom, having a first area in the form of a concentric ring (22), which at its outer circumference is connected to the lower end of the side wall, and a second area (23), which forms the central zone of the bottom of the container and is connected to the first, the inner circumference of the ring area and is closer to the top of the container than the first, ring area, k ä characterized by the fact that the second area in its center has a downwardly projecting bottom closure seam (24). A method of making a one-piece container according to claim 1, wherein a rectangular blank of a foam material is formed into a cylindrical sleeve with overlapping ends, the overlapping ends are welded together into a vertical seam, the sleeve is placed on a mandrel of smaller diameter and shrunk by heat on the mandrel, the material projecting over the mandrel tip is bent inwards to form the container bottom and pinched in the middle timber of the bottom to form a bottom closure seam, whereupon the container blank is pressed into a beaded mold. on the upper end and an even side wall thickness and for bottom finishing, characterized in that during pressing, the bottom closure seam is taken up on the outside of the bottom in a recess in the mold.