US3145905A - Container construction - Google Patents

Description

Aug. 25, 1964 G. A. MOORE CONTAINER CONSTRUCTION Original Filed Sept. 26, 1958 ATTORNEY:

United States Patent C) 3,145,905 CONTAINER CONSTRUCTION George Arlington Moore, 230 E. 48th St., New York, NY. Original application Sept. 26, 1958, Ser. No. 763,747, new Patent No. 3,066,844, dated Dec. 4, 1962. Divided and this application Sept. 6, 1962, Ser. No. 221,715

4 Claims. (Cl. 229-48) This invention relates to containers of paper board or other sheet material treated on at least one face with a thermoplastic material, and more particularly to a novel body seam construction for such a container which is exceptionally strong and impervious.

This application is a division of my copending application Serial No. 763,747, filed September 26, 1958, now Patent No. 3,066,844, issued December 4, 1962.

Many difficulties have been encountered in the past in attempts to make containers of paper board or other substrate material which are intended to hold liquids or greasy products. The difliculties are due mainly to the deleterious effects of interior wall surface absorption of the product especially the notorious wicking absorption of the product by the raw cut edges of the porous fibrous material that are usually exposed within the interior of the container structure. Attempts to treat such edges against wicking absorption meet with little success.

My copending application discloses one type of impervious corner seam construction which avoids wicking absorption by the raw cut edges. The present invention, however, provides another type of seam forming construction particularly advantageous for containers of large capacity or designed to meet heavy duty load requirements and be economically constructed in use of material.

It is an object of this invention, therefore, to provide a corner seam construction for a container which is both impervious and includes reinforcement means for withstanding heavy vertical loads, such as are engendered by stacking filled containers upon one another, and resisting rough handling.

It is another object of the invention to provide a container wherein the corner seam reinforcement means are integral in union with the container forming blank components. I

A further object of the present invention is to provide a reinforced container suitable for liquids wherein the walls thereof will resist undue swelling by the weight of the liquid contents.

It is another object of the invention to provide such a container wherein the corner junction seam or seams are made impervious and the strong reinforcement means are formed simultaneously in forming the complete structure of the container in a single cycle of operation.

More particularly, this invention relates to containers formed by two elongated paper-plastic blanks arranged in crossed relationship, shaped and pressed by engaging male and female dies which simultaneously constructs the two-ply end wall integral with four side walls of the container. According to the present invention, one of the banks is provided with relatively narrow width marginal flanges disposed longitudinally along selective boundary side edges thereof and being articulated into two-ply hemmed borders overlapped by articulated marginal flanges of the companion blank, then densely compressed by heat-ironing pressure imposed by the engaging dies. Thus, the raw cut edges of the hemmed borders are disposed remotely away from exposure within the interior confines of the constructed container. In this manner, the interior plastic surfaces of the adjacent Walls thereof that meet at the corner junctions of the structure are fused together by the heat-ironing action of the dies in forming the container, thereby rendering the interior thereof free of raw cut edge exposure and thereby impermeable.

3,145,905 Patented Aug. 25, 1964 Other objects and advantages of the invention will be apparent from the following description in which reference is made to the accompanying drawings.

In the drawings:

FIG. 1 is a fragmentary plan view of one of the two component blanks used to construct a particular type of container to which this invention relates;

FIG. 2 is a fragmentary plan view of the blanks preparatory to their formation into a container;

FIG. 3 is a fragmentary view, partially in cross-section, showing the relationship of the dies during formation in completing the construction of the container;

FIG. 4 is a perspective view of the completed container; and

FIG. 5 is a horizontal cross-sectional view taken on line 55 of FIG. 4, and showing the novel seam formed structure of the container.

Referring to the drawings for further details of the present invention, FIG. 1 includes a particular blank 4 that may be used in the construction of the above container. The blank is provided with a central panel 5 separated by two parallel spaced score lines 6 and having two parallel spaced transversely disposed side cut edges 7 each of two lateral panel portions 8 having outwardly sloping score lines 9 extending outwardly from each of the opposed scored lines 6, and marginal flange portions 17 projecting outwardly from the score lines 9 of each panel 8. The exterior surface side of the central panel 5 of the blank including one of the laterally extended panels 8 is provided with a pattern coated deposit of a non-thermoplastic material such as may be a clear lacquer 11, for the purpose described in my above-mentioned copending application.

A primary blank is used in conjunction with the blank 4, and for purposes of illustration the blank 4 is shown in FIG. 2 crossed by the primary blank 27. This blank is provided with a central panel 28 with boundary score lines that are arranged in transversely opposite pairs 29 and 39 respectively. Panel portions 31 each extend laterally outward of each score line 30 and have outwardly sloping boundary score lines 32. Each panel 31 is provided with a pair of opposed longitudinal flanges 33 having outwardly sloped side edge portions 34.

As illustrated in FIG. 2 showing the registered assembly of blanks, it is to be noted that the prepared exterior surface of the central panel portion of the blank 4 is covered by the interior thermoplastic surface of the central panel portion of the blank 27. The container is constructed by first compressing and heating the superimposed central panel walls 5 and 28, and while kept under this compression the laterally extended panels 8 are bent downwardly and inwardly from two corner edges of the end forming panel portion 5, followed by bending the laterally extended panels 31 downwardly and inwardly while articulating their flange portions 33, so that they are brought into overlapping relationship upon the corresponding exterior surface portions of the advance bent panels 8. Heat and pressure that is imposed upon these flange portions effects the seam forming relationships more fully to be described hereinafter. The resultant container 43 is shown in FIG. 4.

FIG. 3 illustrates the dies which may be employed to form the complete container. One of the major parts consists of a male die form member 44 having four side walls and an end wall with surfaces provided conforming in shape coincident with the container to be formed thereupon such as the container 43. The form is provided with an interior core or chamber space 45 through which to circulate water or other cooling fluid in order to control the temperature of the heat that is conducted into the form 44 during the operation of the apparatus. An ejector s3 shaft 46 is provided through the center of the form and having a head plate 47, its top surface forming a major portion of the end wall of the form member, the shaft and head having a vent hole 48.

A first functional tool part in the apparatus is a platen head 50 that is mounted upon the end of a shaft 51 adapted to slide by actuated moving means. The head is provided with heating means such as an electrical cartridge element 52 that may be inserted or otherwise attached thereto and connected through a temperature control thermostat and to a source of electrical current supply. The heated platen head upon being actuated by its shaft is moved into surface to surface contact with the superposed wall portion 28 of the previously registered blanks 4 and 27, see FIG. 3, placed upon the end wall of the male form. High pressure actuated upon the top end of the shaft 51 causes the bottom surface of the head 50 to heat and compress the wall layers 5 and 28 together into combined relationship.

Working in conjunction with the male form and platen head is a female form member 53 hereinafter referred to as a female die and having four side walls with inner surfaces of the wall cavity shaped to be coincident with the exterior of the container to be formed. The die 53 may be supported on a cross head carriage 54 that is adapted to be reciprocated in stroke movements and dwell periods by actuating mechanical or other means. The inner wall surfaces of the die substantially are flatly in parallel with the side wall surfaces of the male form when engaged thereupon. The die 53 is provided with electrical heating elements 55 that may be inserted into holes drilled into the walls of the die, each element being preferably located adjacent each of the four corner ends of the side walls thereof. These heater elements are to be Wire circuit connected through a suitable temperature control thermostat to the electrical current supply line. Following the operational function of the platen head 50, the female die 53 is caused by actuated means to move downwardly upon the outwardly extended panels of the firmly clamped central portions of the blanks 4 and 27. The mouth of the die is arranged with a pair of opposed projected flexible prongs (not shown) that first engage the surface portions of the panels 8 of the blank 4 and bending these two panels downwardly each from a corner edge 6 of its clamped wall section and directed inwardly upon the coincident side wall surfaces of the male form 44 and followed by the bending of the panels 31 of the blank 27 from the corner edges 30 and upon the adjacent side wall surfaces of the male form by the directing action of the inner wall surfaces of the moving female die. During this action, the flanges 33 are articulated along their respective corner edges 32 and 29 in this order by the coaction of the interior wall surfaces of the die thereby placing the plastic face of the bent flanges upon the corresponding exterior surface portions of the first bent panels 8. As the heated female die nears the end of its downward movement the wedge-like taper of the inner surfaces of the side walls opposed by the like taper walls of the male form begins to heat iron the exterior surfaces of the die articulated flanges 33 almost completing the construction of the container.

The effect on the blanks when the female die reaches the end of its downward movement will be discussed with reference to FIG. 5 which clearly illustrates the present invention. The blank 4 is precreased along its score lines 9 so that before the blanks are acted upon by the dies, the flanges 17 are bent toward the exterior face of the blank. As the female die cavity articulates the flanges 33 of the blank 27, it also articulates the partially bent flanges 17 and folds them back 180 against the exterior face of the blank 4. At the same time, the flanges 33 are folded down on top of the flanges 17. The thermoplastic film on the interor surface of the panel 3 extended on the folded flange 17 is brought into face to face contact with the film 60 on the interior surface of the adjacent 41. side Wall 31 including a portion of the film on its folded flange 33 thereby providing two thicknesses of the film material disposed at the wall abutted turned corner edge 57 and between the surfaces of the flange 17 and the corresponding portion of the flange 33.

When the female die reaches the end of its cycle of movement, considerable heat-ironing pressure is applied to the flanges 17 and 33 and the marginal portion of the panels 8 upon which the flanges 17 are turned back. As a result, these three layers are densely compacted into a combined thickness of the extended two layers of material constituted by the wall panel 8 and flanges 33 illustrated in FIG. 5. Hence, the density of the highly-compressed marginal flange section 17 of material is greatly increased in order to close and harden the porosity of the paperboard part of the material and thereby arrest the normal tendency of the turned corner edge 57 of the flange to wick-absorb moisture, liquids or greases.

Further protection against this tendency has been provided by the fact that the meeting interior surfaces of the thermoplastic film is activated and heat-fused together thereby completely encasing the flange 17 and its corner edge abutment to provide a strongly reinforced and impervious seam formed construction in the structure of the container.

Thus, the thermoplastic film 60 is squeezed outwardly at the same time that the flange 17 and adjacent regions are densely compressed into abutment against the film lining of the opposing wall 31. The heat-ironing pressure imposed that forms the compacted wall sections causes the meeting portions of film material 60 at the corners to heat-fuse together and thus solidly encase the compressed regions within the film skin material, thereby rendering the container seams impermeable. Due to the fact that these corner regions of the structure have been highly compressed and thereby strongly reinforced, the normal tendency of the joined plastic film to break loose due to wall stress and distortion effects in handling the container is arrested and insures the continued stability of the impervious interior surface structure of the container. In addition, since the raw cut edge of the flange 17 is located between the panel 8 and the flange 33, it is not in direct communication nor exposed within the interior of the container.

It will be seen that each corner of the container formed according to this invention is provided with three plies of densely compressed material. These corners are, therefore, extremely strong and resistant to heavy vertical loads such as imposed by stacking containers on top of each other.

The invention has been shown and described in preferred form only and by way of example and many variations may be made which will fall within the spirit and scope of the invention. For example, the longitudinal body seam of this invention may be embodied in other species of container constructions if desired. It is understood, therefore, that the invention is not limited to any specific form or embodiment except insofar as such limitations are set forth in the appended claims.

What is claimed is:

1. A container made of foldable paper sheet material coated on its inner surface with a film of thermoplastic material and having four side walls, each of two opposed side walls of said container having relatively narrow flanges turned back upon the exterior surface of their respective side wall to form turned edges abutting the thermoplastic coated inner faces of the other two side walls, said other side walls each having relatively wide marginal flanges along either edge thereof, said latter flanges overlying said narrow flanges, each of said narrow flanges, the region of the side wall which it overlaps, and the region of said wide flange overlying it being densely compressed to a thickness less than the initial three ply thickness of the side wall and two flanges, the thermoplastic coating on said turned edges being blended under heat and pressure with the thermoplastic film on the adjacent other side wall in order to provide a film-encased seam between each of said compressed regions and the side wall against which it abuts.

2. A container according to claim 1 wherein the thermoplastic coating on each of said narrow flanges is blended under heat and pressure with the thermoplastic coating on the wide flange overlying it.

3. A container made of foldable paper board coated on its inner surface with a film of thermoplastic material, said container having four side walls arranged in opposed pairs and a two-ply end wall, the inner ply of said end Wall and one of said opposed pairs of side walls forming one integral U-shaped element, and the outer ply of said end wall and the other of said pairs of side walls forming another integral U-shaped element, said one U-shaped element having two relatively narrow flanges extending continuously along said one pair of side walls and turned back upon their respective side walls to form turned edges, said turned edges abutting the inner faces of said pair of side walls, said other side walls each having relatively wide marginal flanges along either edge thereof, said latter flanges overlying said narrow flanges, each of said narrow flanges, the region of the side wall which it is turned back upon, and the region of said wide flange overlying it being densely compressed to a thickness less than the initial three ply thickness of the side wall and flanges to strengthen said flanges and regions and reduce their porosity, and the thermoplastic film coating on said turned edges being blended under heat and pressure with the thermoplastic film on the adjacent walls of said other pair in order to provide a continuous film-encased seam between each of said continuous compressed regions and the side wall against which it abuts.

4. In a container formed of paper board having its inner surface combined with thermoplastic film material, said container including a side wall panel having a marginal flange extended along its longitudinal side and turned back upon its panel exterior surface, an adjacent side wall panel meeting said first mentioned side wall panel at a corner of the container and having a marginal flange extended along its longitudinal side, said last mentioned marginal flange being arranged at right angles to said adjacent side wall panel and its interior plastic surface overlapping the plastic surface of the first mentioned turned flange, said flanges being densely compressed to a thickness less than their original thickness by imposed heat and pressure whereby the plastic film meeting surfaces are heat fused together in impermeable seam forming relationship, whereby the raw out edge of the first mentioned marginal flange is disposed and compressed between a section of said first mentioned side wall panel and the flange of said adjacent wall panel.

References Cited in the file of this patent UNITED STATES PATENTS 1,041,504 Moore Oct. 15, 1912 2,190,479 Moore Feb. 13, 1940 2,234,167 Hothersall Mar. 11, 1941 2,333,330 Moore Nov. 2, 1943 3,066,844 Moore Dec. 4, 1962

Claims (1)

1. A CONTAINER MADE OF FOLDABLE PAPER SHEET MATERIAL COATED ON ITS INNER SURFACE WITH A FILM OF THERMOPLASTIC MATERIAL AND HAVING FOUR SIDE WALLS, EACH OF TWO OPPOSED SIDE WALLS OF SAID CONTAINER HAVING RELATIVELY NARROW FLANGES TURNED BACK UPON THE EXTERIOR SURFACE OF THEIR RESPECTIVE SIDE WALL TO FORM TURNED EDGES ABUTTING THE THERMOPLASTIC COATED INNER FACES OF THE OTHER TWO SIDE WALLS, SAID OTHER SIDE WALLS EACH HAVING RELATIVELY WIDE MARGINAL FLANGES ALONG EITHER EDGE THEREOF, SAID LATTER FLANGES OVERLYING SAID NARROW FLANGES, EACH OF SAID NARROW FLANGES, THE REGION OF THE SIDE WALL WHICH IT OVERLAPS, AND THE REGION OF SAID WIDE FLANGE OVERLYING IT BEING DENSELY COMPRESSED TO A THICKNESS LESS THAN THE INITIAL THREE PLY THICKNESS OF THE SIDE WALL AND TWO FLANGES, THE THERMOPLASTIC COATING ON SAID TURNED EDGES BEING BLENDED UNDER HEAT AND PRESSURE WITH THE THERMOPLASTIC FILM ON THE ADJACENT OTHER SIDE WALL IN ORDER TO PROVIDE A FILM-ENCASED SEAM BETWEEN EACH OF SAID COMPRESSED REGIONS AND THE SIDE WALL AGAINST WHICH IT ABUTS.

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