Special receptacle or package – Structural features for vertical stacking – i.e. – similar... – Closure structure specified for stacking
Patent
1995-05-02
1997-09-02
Pollard, Steven M.
Special receptacle or package
Structural features for vertical stacking, i.e., similar...
Closure structure specified for stacking
220 15, B65D 602
Patent
active
056622236
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to containers; and more specifically, to a plastic, stackable container comprising a lid and a box, wherein the stacking strength of the container, especially of the lid, is considerably increased over that of existing containers.
2. Discussion of the Prior Art
Presently known stackable plastic containers comprising load carrying lids are not suitable for heavy payloads due to their structural design.
Reinforcing means such as webs, ribs, beams, girders and the like, can be placed on or formed as an integral part of the lid. It is, however, impracticable to arrange such reinforcements on the lower horizontal surfaces around the border of the lid because of small contact area between said horizontal surfaces and the upper rim of the box. This results in strength and stability problems that are especially pronounced in the four corners of the lid where up to 80% of the strain caused by weights placed on top of the lid is absorbed. The strain related diagonally inwards and/or downwards directed forces will inevitably bend the inner area of the lid downwards and the four corners upwards, whereby the lid finally will be squeezed down into the box. Such an impact on a lid will pose an obvious and very high risk of lopsidednesses, which finally will overturn a stack of containers.
SUMMARY OF THE INVENTION
Above discussed problems and impediments have through the present invention been solved and a new concept for stackable containers, baskets or the like has been brought about. The container comprises having recesses located in the four upper corners of the box, said recesses having vertical surfaces arranged so that an angle of less than 135.degree. is formed on the inside of the box between the vertical surfaces and the associated walls; and surrounding border, which lid in its four corners is provided with means arranged on the lower surface, which means comprise vertical surfaces intended to cooperate with the corresponding vertical surfaces of the recesses in the rim of the box.
The corresponding and cooperating vertical surfaces counteracts diagonally inwards and/or downwards directed forces, caused by heavy weights placed on top of the lid said forces tend to bend the inner area of the lid downwards and the four corners upwards. The lid will, hence, not be squeezed down into the box.
In various embodiments of the present invention, the lid can be provided with reinforcing twin-walled sections or profiles arranged at its four corners and/or perpendicularly arranged to at least two opposite sides. Reinforcing means such as webs, ribs, beams, girders or the like can, furthermore, be placed on or constitute an integrated part of the lower surface of the lid. Reinforcements as disclosed above result in a lid having a substantially increased carrying capacity. The lid can also while still being a part of the container according to the invention, be used with boxes having an upper plane-surfaced rim without matching recesses.
The lid can, in order to further improve the stability of a stack of containers and avoid lopsidednesses, be provided with guiding means arranged in the four corners of the upper surface. The guiding means are intended to define the location of a second container or the like stacked or piled upon the lid.
In a preferred embodiment, diagonally and perpendicularly arranged reinforcing profiles can, in order to further improve the absorption of inwards and downwards directed forces (as previously discussed) and thus improve the carrying capacity of the lid, be placed on or constitute an integrated part of the upper and/or the lower surface of the lid. The lid can, according to one embodiment, be provided with an outer surrounding downwards directed edge having a height of at least 20 mm, which edge interacts with an outer vertical surface surrounding the rim of the box. Such an outer edge contributes to prevent penetration of moisture and contaminations into the container as well as it further prevents the l
REFERENCES:
patent: 3586205 (1971-06-01), Van Daalen
patent: 4848580 (1989-07-01), Wise
patent: 4936615 (1990-06-01), Moore
patent: 5253776 (1993-10-01), Decroix et al.
patent: 5332114 (1994-07-01), Sano et al.
Perstorp AB
Pollard Steven M.
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