CA1216248A - Container of thermoplastic material, process and apparatus for its manufacture - Google Patents
Container of thermoplastic material, process and apparatus for its manufactureInfo
- Publication number
- CA1216248A CA1216248A CA000453812A CA453812A CA1216248A CA 1216248 A CA1216248 A CA 1216248A CA 000453812 A CA000453812 A CA 000453812A CA 453812 A CA453812 A CA 453812A CA 1216248 A CA1216248 A CA 1216248A
- Authority
- CA
- Canada
- Prior art keywords
- container
- core
- blank
- section
- cross
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D21/00—Nestable, stackable or joinable containers; Containers of variable capacity
- B65D21/02—Containers specially shaped, or provided with fittings or attachments, to facilitate nesting, stacking, or joining together
- B65D21/0233—Nestable containers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
- B29C61/02—Thermal shrinking
- B29C61/025—Thermal shrinking for the production of hollow or tubular articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D11/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of plastics material
- B65D11/02—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of plastics material of curved cross-section
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Stackable Containers (AREA)
- Rigid Containers With Two Or More Constituent Elements (AREA)
- Containers Having Bodies Formed In One Piece (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Making Paper Articles (AREA)
Abstract
Abstract of the Disclosure The specification describes a container of thermoplastic material having a container bottom, the container side wall comprising a foil blank which is connected along two opposite edges, the cross section in the upper area of the container forming a stacking rim which is essentially constant while decreasing in the lower area between the stacking rim and container bottom, in the form of a truncated cone, the cross section in the area which is immediately beneath the stacking rim de-creasing more severely in relation to the container bottom than in the remaining lower area, and the cross section of the stacking rim being smaller in its uppermost circumferential area than it is in the remaining area, specifically decreasing in truncated cone manner. A process for the manufacture of the container is also disclosed.
Description
~LZ~ 8 1 CONTAINER OF THERMOPLASTIC M~TERIAL, PROCESS
AND APPARATUS FOR ITS MANUFACTURE
Background Of The Invention The invention concerns a container fabricated from thermoplastic material. Containers of this type are frequently used in the packaging industry whenever significance is attached, on one hand, to the visibility of the merchandise and, on the other hand, to hygienic packaging. A problem associated with these containers is that normally they must be shipped by the manufacturer to the packaging firm andtor manufacturer of the merchandise to be packaged, and that they require a relatively large shipping volume.
Therefore, it has been previously suggested to produce such containers in the form of a truncated cone so as to enable stacking.
A prior method of producing such containers provides for stamping first a suitable plastic foil blank which is then glued or welded at two opposite overlapping edges.
Thereafter, a suitable bottom part is made which has an angled circular edge. This bottom part is slipped over the container cylinder, and the edge of the bottom part is glued or welded as well to the overlapped part of the container cylinder. However, this method does not permit any special shaping, for instance providing beads as a stacking rim in the container wall or similar expedient.
The manufacture of a stackable container through truncat~d cone shaping of a round can container wall requires defined foil blanks involving losses in the form of foil scrap.
Another widely practiced method is the hot fonming (deep drawing~ of the entire container. While permitting the production of containers within a certain size range, limitations do exist here as well; these are essentially dictated by the ratio of container height to container 6~8 diameter and/or container width. Depending on the type of foil material used, shallow containers can normally be produced without problems, whereas deep containers involve heavy thickness fluctuations in the container walls, resulting in a limited load capacity of the container. In manufacturing stackable containers in the form of truncated cone container walls, the container cylinder requires a wall inclination of at least five percent, an inclination which is readily recognizable with the naked eye and which is not desirable for all containers. Deep drawing also makes container imprinting relatively expensive, since the printing must be conducted on finish-drawn containers.
When using hard polyvinyl chloride (PVC) for clear plastic packaging it cannot be ruled out, in deep drawing, that sometimes a coloration of the PVC foil will occur which renders the container unusable for the intended purpose.
Therefore, the problem underlying the invention is to so design a stackable thermoplastic container of that type that for reduction of the shipping volume several ~0 containers can be stacked smoothly and without binding and that, for another, this container is easy to manufacture and whereby, specifically, an arbitrary ratio of container diameter to container height may be provided.
lcm/MAB
~2~4~3 Summa~ Of The Invention :This problem is solved in accordance -with the - invention by the provision of a container of thermoplastic material having a substantially constant cross section in an upper area forming a stacking rim and a cross section decreasing in a lower area between the stacking rim and a container bottom in truncated cone configuration, the cross section in the lower area immediately beneath the stacking rim decreasing more severely relative to the decreasing cross section in the remaining lower area, the cross section of the stacking rim in the uppermost area being less than in the remainder of the stacking rim, the container having side walls comprising a rectangular foil blank connected along two opposing edges and a separate container bottom, the bottom being supported by and secured to an inwardly projecting circular flange at a lowermost edge of the lower area and having at least one of a circular depression and an annular circular groove of ;inverted truncated conical configuration in vertical section.
The design of the container from a rectangular Eoil blank where opposite side edges are glued or welded together has the advantage that truncated cone container walls can be made with very little side inclination, such that it cannot be readily recogni~ed with the naked eye but lcm/MAB
. . ~, 6~
nevertheless retains the stackability of the containers.
Since the cross section of the lower area immediately beneath the stacking rim decreases relative to the distance from the container bottom more severely than in the remaining area, a relatively heavy constriction is created beneath the stacking rim, forming practically a "stop" for the upper peripheral edge of the stacking rim, of the adjacent container following below, in which the top container is inserted.
Since the cross section of the stacking rim in its uppermost circumferential area is smaller than in the remaining area, a constriction is created as well on the upper edge of the stacking rim which, when stacking several containers, supports the above "stop function" and, moreover~ facilitates the placement of the container lid, since it is then "guided" on the s-tacking rim by the tapers generated.
The process of the present invention for manufacturing a container of this type comprising the steps of: (a) producing a blank of a container cylinder from a stretch plastic foil material; (b) slipping the blank over a core which determines the final shape of the container cylinder so that the blank includes a rim portion projecting beyond the core; (c) slipping the bottom, being lcm/MAB
~2~
- ~a -a plastic foil having a shrink range lying above that of the stretched plastic foil material, on the core; (d) heating the blank and bottom at a temperature lying between the shrink ranges of the stretched plastic material and the bottom until the blank has assumed at least partially the shape of the core and the rim portion has at least partly wrapped over the bottom; and (e) removing the formed container from the core.
The basic idea of the invention process employs for the manufacture of packaging containers the shrink method previously known for packaging purposes (West German OLS 1,479,805). This method is employed in large scale also for various packaging types, but always in a manner such that the plastic shrink foil envelopes the packaged goods themselves. This method has not yet been used for the manufacture of containers from thermoplastic material independently from the specific shape of the respective packing goods.
The advantages of the method of the invention include the facts that containers with any desired taper can be made, preferably also with little taper of the container cylinder, and that the desired spatial structures can be readily created, for instance a stacking rim.
If desired, it is possible also to include the container bottom in the shrink process so that container lcm/MAB
~6248 - 4b -wall and container bottom can be made in one and the same operation.
Brief Description Of The Drawing An embodiment of the containers of the present invention and of the process for their manufacture will be more fully explained hereafter with the aid of the accompanying drawing:
FIGURE 1 shows a cross section of a container;
FIGURE 2, a side elevation of two stacked containers;
FI&URE 3, apparatus for the manufacture of containers according to FIGURE l; and lcm/MAB
., l FIGURE 4, the finished container cylinder which upon completion of the process of the invention surrounds a core.
Initial Description The container of the invention comprises a container cylinder lO and a container bottom 20 (and a container lid not illustrated in the drawing).
For the illus1rated embodiment of a round can (FIGURE l), the container cylinder lO consists of a rectangular foil blank rolled into circular shape and glued or welded together at the butting side edges, which blanX assumes through the subsequently explained shrinXing onto a core the cross sectional shape illustrated in the figures. Specifically, the cross sectional progression permits the following differentiation:
An upper area A serving as stacking edge lOa, its cross section being esentially constant but tapering inwardly in its uppermost circumferential area C, and a lower area B representing the major part of the container wall and having a truncated cone shape which makes it possible to nest two containers tFlGURE 2) until their stacking rims rest on each other.
The round can features for that purpose in its area of transition to the stacking rim lOa relatively severe reduction of cross section, whereas the reduction of cross section is constant in the remaining area B
relative to the height of the container.
FIGURE 2 shows schematically how containers of that shape can be nested; evident are the overlapping ares 60, 70 of the two containers where the cylindrical container blank is formed in an alternative embodiment by overlapping and welding and/or glueing of the rectangular foil hlank.
On its other end, the container cylinder lO has a ~6'~
1 circular flange lOb projecting inwardly in which the container bottom 20 is placed.
The container bottom 20 features previously known depressions 22 and/or circular grooves 21 for stabilization.
The manufacture of the containers of the invention proceeds as follows (FIGUR~ 3 and 4):
To begin with, a blank 11 of the eventual container cylinder is made by stamping rectangular plastic foil blanks which, as the case may be, are imprinted and glued or w~lded so as to form a cylinder.
This blank 11 is slipped over a core 13 which determines the final shape of the container cyllnder 10;
FIGURE 3 shows for clarity a core 13 with a relatlvely large taper.
Next, the core 13 with the blank 11 is introduced into a furnace 40 featuring heating elements 41 in the form of hot air noz21es, whereafter the shrinking process of the stretched plastic foil begins, starting at the lower container end. Upon completion of the shrinking process the container cylinder 10 preferably is completely in contact with the core 13, with the projecting rim 21 of the blank 11 producing the circular flange lOb of the finished container 10.
Upon completion of the shrinking process the finished container cylinder 10 is remove~ from the core 13. In the case of a heavily tapered conical area C of the stacking eage lOa the core 13 has suitably a two-part design with a gap 13a between the two core halves in their expanded condition. The two core halves are then caused to contract for removal of the container cylinder 10, that is, the gap 13a is closed. The diameter of the contracted core half should not be greater than the smallest diameter in the area C of the stacking rim lOa, i.e., the opening diameter of the container. Upon 1 removal of the container a container bottom 20 is then introduced into the container from above until it sits on the circular bead or flange lOb, where it is either glued in place or ~elded to the bead lOb by means of conventional welding devices (for instance, "sonotrodes"
(supersonic welding) or electrodes (high frequency welding).
Simple in principle, this type of manufacture can be arbitrarily varied and also automated in simple ways.
The placement of the blank, introduction into the furnace 40, removal of the container cylinder, introduction and gluing and/or welding of the container bottom can be conducted by conventional process technology, with the container component handling essentially being performed with the aid of pneumatic machine components.
In a modi~ication of the described embodiment, this process makes it readily possible to integrate the container bottom 20 with the shrinXing of the blank 11, and in fact, in a way such that the container bottom has a diameter somewhat larger than the end face of the form core 13, producing then in the shrinking of the blank a bead around the container bottom which retains it in a form-fitting manner. This will eliminate additional operations such as the gluing or welding of the container bottom to the container cylinder.
This process can be performed especially when the material of the container bottom 20 differs from the material of the blank 11, so that the container bottom 20 will not be affected by the shrinking operation in the furnace 40.
Specifically, this can be accomplished either by making the container hottom from cardboard or by providing for it a thermoplastic foil having a shrink range which lies above the shrink range of the plastic foil of the container cylinder 10.
~Z~6241~
1 With other shapes of the container cylinder 10 it may be favorable to somewhat temper the core 13 as well, and to supply heat through the core, at a temperature below the shrink range o the plastic material. For purposes of producing a particularly uniform container cylinder, specifically when it is more heavily tapered, a vacuum may be produced between the core 13 and the blank 11 during heating, thereby supporting the blank 11 in making intimate contact with the core 13.
In the framework of an automated production of the containers of the invention, the furance 40 may also be fashioned as a shrink tunnel through which the core 13 is passed with the blank 11 slipped on it.
The advantages of the container of the present invention can be summarized as follows:
It consists completely (container and lid) of homogenous material without any additional aid, and the cylindrical shape of the upper container part assures an accurately fitting and close placement of the lid and thus a tight seal against environmental influences, for instance no influencing by odors.
The uniorm container cylinder thickness guaranteed by the shrink process over the entire circumferential area results in a high upset load capacity, since weak areas due to localized thinning of material are eliminated.
The stackability permits a reduction of storage and shipping volume to approximately one-tenth of the volume required for containers which cannot be stacked.
Automatic stacking and unstacking of several containers enables an automation and thus a considerable increase of the packing output. Also large-volume containers 7 for instance those which no longer can be reasonably produced by the previously described deep drawing process~ can be manufactured economically by the process of the 1 invention.
Since the container manufacture involves no scrap, a minimi~ation of material consumption is guaranteed as well.
The container oE the invention is readily able to meet legal requirements.
AND APPARATUS FOR ITS MANUFACTURE
Background Of The Invention The invention concerns a container fabricated from thermoplastic material. Containers of this type are frequently used in the packaging industry whenever significance is attached, on one hand, to the visibility of the merchandise and, on the other hand, to hygienic packaging. A problem associated with these containers is that normally they must be shipped by the manufacturer to the packaging firm andtor manufacturer of the merchandise to be packaged, and that they require a relatively large shipping volume.
Therefore, it has been previously suggested to produce such containers in the form of a truncated cone so as to enable stacking.
A prior method of producing such containers provides for stamping first a suitable plastic foil blank which is then glued or welded at two opposite overlapping edges.
Thereafter, a suitable bottom part is made which has an angled circular edge. This bottom part is slipped over the container cylinder, and the edge of the bottom part is glued or welded as well to the overlapped part of the container cylinder. However, this method does not permit any special shaping, for instance providing beads as a stacking rim in the container wall or similar expedient.
The manufacture of a stackable container through truncat~d cone shaping of a round can container wall requires defined foil blanks involving losses in the form of foil scrap.
Another widely practiced method is the hot fonming (deep drawing~ of the entire container. While permitting the production of containers within a certain size range, limitations do exist here as well; these are essentially dictated by the ratio of container height to container 6~8 diameter and/or container width. Depending on the type of foil material used, shallow containers can normally be produced without problems, whereas deep containers involve heavy thickness fluctuations in the container walls, resulting in a limited load capacity of the container. In manufacturing stackable containers in the form of truncated cone container walls, the container cylinder requires a wall inclination of at least five percent, an inclination which is readily recognizable with the naked eye and which is not desirable for all containers. Deep drawing also makes container imprinting relatively expensive, since the printing must be conducted on finish-drawn containers.
When using hard polyvinyl chloride (PVC) for clear plastic packaging it cannot be ruled out, in deep drawing, that sometimes a coloration of the PVC foil will occur which renders the container unusable for the intended purpose.
Therefore, the problem underlying the invention is to so design a stackable thermoplastic container of that type that for reduction of the shipping volume several ~0 containers can be stacked smoothly and without binding and that, for another, this container is easy to manufacture and whereby, specifically, an arbitrary ratio of container diameter to container height may be provided.
lcm/MAB
~2~4~3 Summa~ Of The Invention :This problem is solved in accordance -with the - invention by the provision of a container of thermoplastic material having a substantially constant cross section in an upper area forming a stacking rim and a cross section decreasing in a lower area between the stacking rim and a container bottom in truncated cone configuration, the cross section in the lower area immediately beneath the stacking rim decreasing more severely relative to the decreasing cross section in the remaining lower area, the cross section of the stacking rim in the uppermost area being less than in the remainder of the stacking rim, the container having side walls comprising a rectangular foil blank connected along two opposing edges and a separate container bottom, the bottom being supported by and secured to an inwardly projecting circular flange at a lowermost edge of the lower area and having at least one of a circular depression and an annular circular groove of ;inverted truncated conical configuration in vertical section.
The design of the container from a rectangular Eoil blank where opposite side edges are glued or welded together has the advantage that truncated cone container walls can be made with very little side inclination, such that it cannot be readily recogni~ed with the naked eye but lcm/MAB
. . ~, 6~
nevertheless retains the stackability of the containers.
Since the cross section of the lower area immediately beneath the stacking rim decreases relative to the distance from the container bottom more severely than in the remaining area, a relatively heavy constriction is created beneath the stacking rim, forming practically a "stop" for the upper peripheral edge of the stacking rim, of the adjacent container following below, in which the top container is inserted.
Since the cross section of the stacking rim in its uppermost circumferential area is smaller than in the remaining area, a constriction is created as well on the upper edge of the stacking rim which, when stacking several containers, supports the above "stop function" and, moreover~ facilitates the placement of the container lid, since it is then "guided" on the s-tacking rim by the tapers generated.
The process of the present invention for manufacturing a container of this type comprising the steps of: (a) producing a blank of a container cylinder from a stretch plastic foil material; (b) slipping the blank over a core which determines the final shape of the container cylinder so that the blank includes a rim portion projecting beyond the core; (c) slipping the bottom, being lcm/MAB
~2~
- ~a -a plastic foil having a shrink range lying above that of the stretched plastic foil material, on the core; (d) heating the blank and bottom at a temperature lying between the shrink ranges of the stretched plastic material and the bottom until the blank has assumed at least partially the shape of the core and the rim portion has at least partly wrapped over the bottom; and (e) removing the formed container from the core.
The basic idea of the invention process employs for the manufacture of packaging containers the shrink method previously known for packaging purposes (West German OLS 1,479,805). This method is employed in large scale also for various packaging types, but always in a manner such that the plastic shrink foil envelopes the packaged goods themselves. This method has not yet been used for the manufacture of containers from thermoplastic material independently from the specific shape of the respective packing goods.
The advantages of the method of the invention include the facts that containers with any desired taper can be made, preferably also with little taper of the container cylinder, and that the desired spatial structures can be readily created, for instance a stacking rim.
If desired, it is possible also to include the container bottom in the shrink process so that container lcm/MAB
~6248 - 4b -wall and container bottom can be made in one and the same operation.
Brief Description Of The Drawing An embodiment of the containers of the present invention and of the process for their manufacture will be more fully explained hereafter with the aid of the accompanying drawing:
FIGURE 1 shows a cross section of a container;
FIGURE 2, a side elevation of two stacked containers;
FI&URE 3, apparatus for the manufacture of containers according to FIGURE l; and lcm/MAB
., l FIGURE 4, the finished container cylinder which upon completion of the process of the invention surrounds a core.
Initial Description The container of the invention comprises a container cylinder lO and a container bottom 20 (and a container lid not illustrated in the drawing).
For the illus1rated embodiment of a round can (FIGURE l), the container cylinder lO consists of a rectangular foil blank rolled into circular shape and glued or welded together at the butting side edges, which blanX assumes through the subsequently explained shrinXing onto a core the cross sectional shape illustrated in the figures. Specifically, the cross sectional progression permits the following differentiation:
An upper area A serving as stacking edge lOa, its cross section being esentially constant but tapering inwardly in its uppermost circumferential area C, and a lower area B representing the major part of the container wall and having a truncated cone shape which makes it possible to nest two containers tFlGURE 2) until their stacking rims rest on each other.
The round can features for that purpose in its area of transition to the stacking rim lOa relatively severe reduction of cross section, whereas the reduction of cross section is constant in the remaining area B
relative to the height of the container.
FIGURE 2 shows schematically how containers of that shape can be nested; evident are the overlapping ares 60, 70 of the two containers where the cylindrical container blank is formed in an alternative embodiment by overlapping and welding and/or glueing of the rectangular foil hlank.
On its other end, the container cylinder lO has a ~6'~
1 circular flange lOb projecting inwardly in which the container bottom 20 is placed.
The container bottom 20 features previously known depressions 22 and/or circular grooves 21 for stabilization.
The manufacture of the containers of the invention proceeds as follows (FIGUR~ 3 and 4):
To begin with, a blank 11 of the eventual container cylinder is made by stamping rectangular plastic foil blanks which, as the case may be, are imprinted and glued or w~lded so as to form a cylinder.
This blank 11 is slipped over a core 13 which determines the final shape of the container cyllnder 10;
FIGURE 3 shows for clarity a core 13 with a relatlvely large taper.
Next, the core 13 with the blank 11 is introduced into a furnace 40 featuring heating elements 41 in the form of hot air noz21es, whereafter the shrinking process of the stretched plastic foil begins, starting at the lower container end. Upon completion of the shrinking process the container cylinder 10 preferably is completely in contact with the core 13, with the projecting rim 21 of the blank 11 producing the circular flange lOb of the finished container 10.
Upon completion of the shrinking process the finished container cylinder 10 is remove~ from the core 13. In the case of a heavily tapered conical area C of the stacking eage lOa the core 13 has suitably a two-part design with a gap 13a between the two core halves in their expanded condition. The two core halves are then caused to contract for removal of the container cylinder 10, that is, the gap 13a is closed. The diameter of the contracted core half should not be greater than the smallest diameter in the area C of the stacking rim lOa, i.e., the opening diameter of the container. Upon 1 removal of the container a container bottom 20 is then introduced into the container from above until it sits on the circular bead or flange lOb, where it is either glued in place or ~elded to the bead lOb by means of conventional welding devices (for instance, "sonotrodes"
(supersonic welding) or electrodes (high frequency welding).
Simple in principle, this type of manufacture can be arbitrarily varied and also automated in simple ways.
The placement of the blank, introduction into the furnace 40, removal of the container cylinder, introduction and gluing and/or welding of the container bottom can be conducted by conventional process technology, with the container component handling essentially being performed with the aid of pneumatic machine components.
In a modi~ication of the described embodiment, this process makes it readily possible to integrate the container bottom 20 with the shrinXing of the blank 11, and in fact, in a way such that the container bottom has a diameter somewhat larger than the end face of the form core 13, producing then in the shrinking of the blank a bead around the container bottom which retains it in a form-fitting manner. This will eliminate additional operations such as the gluing or welding of the container bottom to the container cylinder.
This process can be performed especially when the material of the container bottom 20 differs from the material of the blank 11, so that the container bottom 20 will not be affected by the shrinking operation in the furnace 40.
Specifically, this can be accomplished either by making the container hottom from cardboard or by providing for it a thermoplastic foil having a shrink range which lies above the shrink range of the plastic foil of the container cylinder 10.
~Z~6241~
1 With other shapes of the container cylinder 10 it may be favorable to somewhat temper the core 13 as well, and to supply heat through the core, at a temperature below the shrink range o the plastic material. For purposes of producing a particularly uniform container cylinder, specifically when it is more heavily tapered, a vacuum may be produced between the core 13 and the blank 11 during heating, thereby supporting the blank 11 in making intimate contact with the core 13.
In the framework of an automated production of the containers of the invention, the furance 40 may also be fashioned as a shrink tunnel through which the core 13 is passed with the blank 11 slipped on it.
The advantages of the container of the present invention can be summarized as follows:
It consists completely (container and lid) of homogenous material without any additional aid, and the cylindrical shape of the upper container part assures an accurately fitting and close placement of the lid and thus a tight seal against environmental influences, for instance no influencing by odors.
The uniorm container cylinder thickness guaranteed by the shrink process over the entire circumferential area results in a high upset load capacity, since weak areas due to localized thinning of material are eliminated.
The stackability permits a reduction of storage and shipping volume to approximately one-tenth of the volume required for containers which cannot be stacked.
Automatic stacking and unstacking of several containers enables an automation and thus a considerable increase of the packing output. Also large-volume containers 7 for instance those which no longer can be reasonably produced by the previously described deep drawing process~ can be manufactured economically by the process of the 1 invention.
Since the container manufacture involves no scrap, a minimi~ation of material consumption is guaranteed as well.
The container oE the invention is readily able to meet legal requirements.
2~
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Container of thermoplastic material having a substantially constant cross section in an upper area forming a stacking rim and a cross section decreasing in a lower area between said stacking rim and a container bottom in truncated cone configuration, the cross section in said lower area immediately beneath said stacking rim decreasing more severely relative to the decreasing cross section in the remaining lower area, the cross section of said stacking rim in the uppermost area being less than in the remainder of said stacking rim, said container having side walls comprising a rectangular foil blank connected along two opposing edges and a separate container bottom, said bottom being supported by and secured to an inwardly projecting circular flange at a lowermost edge of said lower area and having at least one of a circular depression and an annular circular groove of inverted truncated conical configuration in vertical section.
2. A process for the manufacture of containers from thermoplastic material according to claim 1, comprising the steps of: (a) producing a blank of a container cylinder from a stretch plastic foil material;
(b) slipping said blank over a core which determines the final shape of the container cylinder so that said blank includes a rim portion projecting beyond said core; (c) slipping said bottom, being a plastic foil having a shrink range lying above that of said stretched plastic foil material, on said core; (d) heating said blank and bottom at a temperature lying between the shrink ranges of said stretched plastic material and said bottom until the blank has assumed at least partially the shape of said core and said rim portion has at least partly wrapped over said bottom; and (e) removing the formed container from said core.
(b) slipping said blank over a core which determines the final shape of the container cylinder so that said blank includes a rim portion projecting beyond said core; (c) slipping said bottom, being a plastic foil having a shrink range lying above that of said stretched plastic foil material, on said core; (d) heating said blank and bottom at a temperature lying between the shrink ranges of said stretched plastic material and said bottom until the blank has assumed at least partially the shape of said core and said rim portion has at least partly wrapped over said bottom; and (e) removing the formed container from said core.
3. Process according to claim 2, wherein heat is supplied by means of hot air.
4. Process according to claim 2 or 3, the application of heat to the blank begins in the area where said blank varies most from the shape of said core.
5. Process according to claim 2, wherein said container bottom is a plastic foil which is not stretched, and that the melting temperature of this plastic ranges above the heating temperature.
6. Process according to claim 2, wherein said container bottom is welded to said circular flange of the container cylinder by application of pressure.
7. Process according to claim 2, wherein said core is heated to a temperature below the shrink range of the stretched plastic foil material.
8. Process according to claim 2, wherein during heating a vacuum is generated between said core and said blank.
9. Process according to claim 2, wherein heat is supplied through said core.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEG8315039.0 | 1983-05-21 | ||
| DE19838315039 DE8315039U1 (en) | 1983-05-21 | 1983-05-21 | CONTAINER MADE OF THERMOPLASTIC PLASTIC |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1216248A true CA1216248A (en) | 1987-01-06 |
Family
ID=6753556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000453812A Expired CA1216248A (en) | 1983-05-21 | 1984-05-08 | Container of thermoplastic material, process and apparatus for its manufacture |
Country Status (7)
| Country | Link |
|---|---|
| BE (1) | BE899418A (en) |
| CA (1) | CA1216248A (en) |
| CH (1) | CH663593A5 (en) |
| DE (1) | DE8315039U1 (en) |
| ES (2) | ES532626A0 (en) |
| FR (1) | FR2546130B1 (en) |
| GB (1) | GB2143506B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3422199A1 (en) * | 1984-06-15 | 1985-12-19 | Hans Hagner | Thermoplastic container and process for the production thereof |
| NL9001243A (en) * | 1990-05-31 | 1991-12-16 | Kelder Plastibox B V | PACKAGING. |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2989785A (en) * | 1959-06-25 | 1961-06-27 | William F Stahl | Method of forming plastic containers |
| USRE29320E (en) * | 1965-03-24 | 1977-07-26 | Owens-Illinois, Inc. | Nestable containers |
| US3854583A (en) * | 1971-12-23 | 1974-12-17 | Owens Illinois Inc | Nestable fabricated thermoplastic container and method of fabrication same |
| CA1041261A (en) * | 1972-12-08 | 1978-10-31 | Ikuya Shimano | Method for producing receptacles from thermoplastic resin foam sheet |
| GB2120996A (en) * | 1982-05-27 | 1983-12-14 | Mardon Illingworth | Nestable one-piece can body or lid |
-
1983
- 1983-05-21 DE DE19838315039 patent/DE8315039U1/en not_active Expired
-
1984
- 1984-03-20 CH CH139884A patent/CH663593A5/en not_active IP Right Cessation
- 1984-04-11 FR FR8405752A patent/FR2546130B1/en not_active Expired
- 1984-04-13 BE BE0/212760A patent/BE899418A/en not_active IP Right Cessation
- 1984-04-26 GB GB08410742A patent/GB2143506B/en not_active Expired
- 1984-05-08 CA CA000453812A patent/CA1216248A/en not_active Expired
- 1984-05-18 ES ES532626A patent/ES532626A0/en active Granted
-
1985
- 1985-02-27 ES ES1985284922U patent/ES284922Y/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2143506A (en) | 1985-02-13 |
| GB2143506B (en) | 1987-03-04 |
| CH663593A5 (en) | 1987-12-31 |
| FR2546130B1 (en) | 1987-06-26 |
| ES8506234A1 (en) | 1985-07-16 |
| GB8410742D0 (en) | 1984-05-31 |
| ES284922U (en) | 1985-06-16 |
| ES284922Y (en) | 1986-04-01 |
| FR2546130A1 (en) | 1984-11-23 |
| ES532626A0 (en) | 1985-07-16 |
| DE8315039U1 (en) | 1983-10-13 |
| BE899418A (en) | 1984-07-31 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |