GB2281900A - Plastic container formed from a single sheet - Google Patents

Abstract

A plastic container (20) formed from a single sheet preferably having an alveolar structure has folding lines (14, 15) on its base (13) and on two opposite lateral walls which allow the container (20) to fold flat. Wall regions (1, 2 and 5, 6) are held together by welding overlapping portions (40a - 40d) to one another to form weld lines spaced above the base (13) of the container. <IMAGE>

Description

SEALED PLASTIC CONTAINER, MADE FROM A SINGLE SHEET The present invention relates to a container made of plastics and sealed, and particularly to a container assuring a perfect seal in the region of its bottom, said container being folded before it is used, along folding lines obtained on it and on its lateral wails, in order to minimize the space occupied during its transport and storage. Containers made of plastic material, used for substances to be isolated from the environment, and whose bottom is welded to the lateral walls, are already known. If the welding is defective, there may be leaks, in particular of liquids.

An object of the present invention is to produce an improved container made of plastics material.

To this end, the invention may be considered to provide, in one aspect, a sealed plastics container made from a single sheet of plastics material which has folding and cutting lines, the container being welded along welding lines which are arranged at a distance above the base of the container, and in that folding lines allow to fold the container by letting it take the form of a plate with superimposed layers and occupying a small volume.

In a preferred embodiment this is realised, preferably from a single sheet of polypropylene by folding the sheet along folding lines which are present on the bottom itself, and by providing welding lines only from a predetermined height upwards, said height being measured from the bottom of the container.

Thus a preferred container will have a compact form, before its use, with a minimum volume, similar to a plate with superimposed layers.

A preferred container is made from a sheet having an alveolar structure, in order to increase its resistance and reduce its weight.

The present invention will now be described for illustrative and nonb itative purposes, according to the embodiment shown in the annexed drawings in which: Fig. 1 is a plan view of the plastic sheet, preferably having an alveolar structure, and with folding and cutting lines; Fig. 2, is a perspective view of the container, showing how to obtain the three dlzenslonal configuration of the container starting from the plastic sheet of Fig. 1; Fig. 3, is a perspective view of the container, showing only the two ZT shaped welding lines disposed on two opposite walls of the container; Fig. 4 is a perspective view of the container, showing only the folding lines which allow to fold the container;; Fig. 5 is a perspective view of the container, folded along the folding lines of Fig. 4, so as to take the forM of a plate with superimposed layers; Fig. 6 is a plan view of a plastic sheet, preferably having an alveolar structure, and having folding and cutting lines differently arranged with respect to Fig. 1; Fig. 7 is a perspective view of a container obtained from the sheet of Fig. 6; Fig. 8 is a perspective view, similar to Fig. 5, of the container of Fig. 7, in a folded condition suited for its transport.

With reference to Fig. 1, the sheet has faces 1, 2; 3, 4; 3', 4'; 5, 6; 7, 8; 9, 10, sy1metrlcal with respect to the horizontal symMetry axis A-A and two faces 11, 12 sy.metrlcal with respect to the vertical syMmetry axis B-B.

Moreover, these faces are separated by folding lines (discontinuous lines in the figure).

A central square portion 13 Is partitioned into six triangular faces, by eans of a folding line which concides with the vertical synnetry axis B-B and two diagonal folding lines 14, 15.

Four sMall rectangles (shaded zones) 40a, 40b, 40c, 40d which form partial regions of the faces 1, 2, 5, 6, are bounded by short cutting lines 16a, 16b, 18c, and 16d respectively, along one of their smaller sides.

The three dixensional configuration of the container 20 shown in Fig. 2 is obtained from the sheet in the following way: the sheet is folded along the four folding lines which form the sides of the central square portion 13, so that the faces 11, 12, 3 and 3', 4 and 4', will form an angle of about 90 with respect to said central square portion 13, and siiiultaneously the face 11 is superiMposed to the faces 1, 2, 7, 8 and the face 12 is superimposed to the faces 5, 6, 9, 10.

This operation is nore easily understood flaking also reference to Fig. 2.

The central square portion 13 forms the base of the container 20, the two lateral opposite walls 17 and 18 are forked respectively by the faces 3, 3 and 4, 4 (the folding lines which coincide with the symMetry axis B-B of Fig. 1 and which divide up into two equal parts the lateral walls 17 and 18, are not shown in Fig. 2).

The rectangular face 11 is folded over the two trapezoidal faces 1 and 2 and over the two substantially triangular faces 7, 8, these latter being arranged between the external face 11 and the faces 1, 2.

The usefulness of the cutting lines 16a, 16b, 16c, 16d of Fig. 1 is moreover quite clear. The two small rectangles 40a, 40 b are superiMposed in the rectangular region 19 enclosed by two dashed lines and allow to realize the welding between them in said region 19. The resultant welding line 21 is shown in Fig. 3.

A horizontal welding llne 22 intersects the vertical welding line 21 at the point 23 (superImposition of weldings or lap welding) and said line 22 joins together the three superimposed layers of the initial sheet formed by the faces 1, 7, 11 or 2, 8, 11.

Obviously, on the lateral wall 24 opposite to the lateral wall 24, there are corresponding welding lines 21', 22 which intersect at the point 23', the line 21 joining together the small superimposed rectangular portions 40c, 40d of the Initial sheet.

From figures 2, 3 there results therefore a first fundamental feature of the container 20, that is, the fact that it does not have welding lines or cutting lines in the region A below the horizontal welding lines 22, 22 so that in this region the tightness will be perfect.

The figures 4 and 5, on the other hand, show another important feature of the container 20.

The opposite lateral walls 17, 18 and the base 13, are divided up Into two equal parts by a folding line 30 (indicated by a dashed line) coincident with the symmetry axis B-B (Fig. 1) of the Initial sheet.

The container 20 may be folded along said folding line 30 and along the two diagonal folding lines 14, 15 so as to take the form shown in Fig. 5, sinilar to a plate with superimposed layers on whose upper and lower faces there are the "T' shaped welding lines, formed by the welding lines 21, 22 and 21', 22 respectively.

Before their use, it is possible to pile, transport and handle a large number of containers 20, which will occupy a small volume due to this particular folding method of the container, shown in Fig. 5.

With reference to Fig. 6, it can be noticed that apart from two gVX shaped folding lines 140 and 150, the folding and cutting lines are the same as in Fig. 1, which, on the contrary, Included diagonal folding lines 14, 15 on the base 13 of the container.

Fig. 7 shows the location of the folding lines 30, 140 and 150 when the container is welded along the ZTZ shaped welding lines and when it takes its three dimensional configuration. A detailed description of how to obtain the container of Fig. 7 starting from the sheet of Fig. 6 is not required, since this is done in the same tanner as described with reference to Figs 1, 2, 3.

Fig. 8 shows how the container of Fig. 7 may be folded; taking advantage of the folding lines 30, 140 and 150 of Fig. 7, obviously, a form is obtained, which Is different from that of Fig. 5.

Claims (7)

Claims

1. A sealed plastic container, characterized in that it is obtained fro a single sheet which has folding and cutting lines , the container being welded along welding lines which are arranged at a distance above the base of the container, and in that folding lines allow to fold the container by letting it take the forM of a plate with superimposed layers and occupying a Dinirun volume.

2. A container according to claiM 1, characterized in that said welding lines include points of lap welding in order to assure a perfect tightness.

3. A container according to chair 2, characterized in that it comprises a rectangular or square base and four lateral walls , two opposite lateral walls including vertical welding lines and horizontal welding lines , the latter welding together three superimposed layers of the initial sheet, the other two opposite walls and the base including folding lines which allow to fold the container so as to form a plate with superimposed layers, these latter folding lines being formed by two diagonal folding lines of the base and by a line which coincides with the longitudinal symmetry axis of the initial plastic sheet.

4. A container according to claim 2-, characterized in that it has a rectangular or square base and four lateral walls , two opposite lateral walls having vertical welding lines and horizontal welding lines , these latter welding together three superimposed layers of the initial sheet, the other two opposite walls and the base including folding lines which allow to fold the container so as to form a plate with superimposed layers, these latter folding lines being formed by two "V" shaped folding lines on the two opposite lateral walls and by a line which coincides with the longitudinal symmetry axis of the initial plastic sheet.

5. A container according to claim 1, 2, 3 or 4, characterized in that said sheet has an alveolar structure.

6. A container according to any of the preceding claims, characterized In that it is made by the same plastic material, preferably polypropylene.

7. A container made from a sheet of plastics material substantially as hereinbefore described with reference to the accompanying drawings.