AU597025B2 - A plastic container or crate - Google Patents

Description

C X M. 0ON WE A-LTH OF A FS T RA L XA.

)?ATENT' AC *t 952 COMPLETE SPECIFICATVION (original) FOR OFFICE USE 907 in? Class Int- Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: I iU~ ad e inirdxt fr Name of Applicant: WAVIN B.V.

'9 889 99 9 8 Address of Applicant: Handellaan 251, 8031 EM ZWOLLE, THE NETHERLANDS.

Actual Inventor(s) :Coenraad Johannes Bartholomeus Maria BENRAAD Klaas ROSKAM 04 8 9 44 Address for Service: DAVIES COLLISON, Patent Attorneys, 94 1 Little Collins Street, Melbourne, 3000.

Complete Specification for the invention entitled: "A PLASTIC CONTAINER OR CRATE" The folloWing statement is a full description of this inventi-on, including the best method of performing it known to us

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.4 A PLASTIC CONTAINER OR CRATE Theinvention relates to a plastics container or crate comprising a bottom wall, upright walls at least partially extending substantially perpendicular to the bottom wall, a projecting circumferential flange at the upper side of the container or crate, a projecting peripheral stacking flange It 4 in the region of the bottom wall and a stacking edge Sor interspaced stacking edge parts projecting downwardly from below said bottom wall and spaced inwardly from the upright walls so as to be received within the upper 1C periphery of the upright walls of a like container or crate.

A plastics container or crate of this type 6 6 and presents the advantage that it may be manufactured at a rather low cost price.

The main dimensions of plastics containers or crates of the described type are generally normalized at presenf this with respect to stacking them upon pallets having container or crate can only be changed by varying the height.

Containers or crates with the same dimensions in horizontal direction but with different height are therefore usually manufactured by using a mould consisting of a bottom plate and a core, as well as exchangeable side slides which cooperate sealingly with the core and with the bottom plate. Due to a suitable adaptation of the side slides the height of the plastics container or crate is changed and adapted to the demands of the consumer(s) in a simple manner.

Containers or crates of the abovementioned type having upright walls extending perpendicularly to the bottom wall over the total height of the upright walls present the disadvantage, however, that the total weight of a stack of a great number of filled plastics containers or crates will press upon the walls of the lowermost container or crate and as the stacking edge or stacking edge parts is or are accommodated within the circumference of the upright walls, the forces occurring in the upright walls of the lowermost plastics container or crate of a stack cannot be transferred directly towards the stacking edge parts or the stacking edge. The upright walls of the lowermost container or crate will sag, even at a relative low loading of the upright walls. Greater loads will cause said upright walls to sag and bulge towards the surface supporting the lowermost plastics container or crate for instance a floor or a pallet surface.

oa 20 To overcome this problem it has been proposed to provide the upright walls with lower wall parts which S00 converge downwardly so as to terminate directly above the stacking edge or stacking edge parts, whereby when the containers or crates are stacked the loading forces exerted on the lowermost container or crate are transferred S. directly from the upright walls to the stacking edge or stacking edge parts.

This feature of converging lower wall parts will still allow a simple and cheap production of the plastics containers or crates by the so-called combined mould which comprises a core, a bottom plate and exchangeable side slides, as the core and the side slides of a mould may be adapted such, that the lowermost part of said core tapers, whilst the side slides extend parallel therewith.

However, containers or crates with converging lower wall parts present the disadvantage that in a stack of 4

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0£ filled containers or crates the forces ocurring in the upright walls of a container or crate placed on top of a certain container or crate in the stack cannot be transferred directly to the upright walls of that latter container or crate, as the lower wall parts of the upper container or crate terminate next to the upper edge of the lower container or crate at the inner side of it. The forces can only be transferred through the projecting peripheral stacking flange of the upper container or crate. In case of a stack of a great number of filled containers or crates the peripheral stacking edge of a container or crate placed on top of a certain container may be bent upwardly whereby the upper container or crate sinks into the lower container or crate.

Moreover, the surface area of the bottom inside the container or crate with converging lower wall parts is decreased, so that the contents of these containers or crates is less than the contents of containers or crates with the same overall dimensions but with upright walls extending perpendicularly to the bottom wall over the total height of the upright walls.

The object of the present invention is to provide a container or crate for a "family" of mutually stackable containers or crates with different heights which container or crate can be manufactured in an economic way and can be stacked with other containers or crates of the same "family" to great heights when filled and with a contents which is nearly the same as the contents of a container or crate with the same overall dimensions but with upright walls extending perpendicular to the bottom wall over the total height of the upright walls.

This object is attained with a container or crate of the abovementioned type wherein only in the region of the corners of the container or crate the upright walls are provided with lower wall parts which converge downwardly so as to terminate substantially above the stacking edge or a

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Ii 1 -4stacking edge parts, and the uprigh' .'Is between the corner regions extend substantially perpendicular to the bottom wall over the total height of the upright walls.

A container or crate according to the invention can be manufactured with different heights in an economic way by means of a mould with exchangeable side slides. The bottom surface area is as large as possible.

The forces in the upright walls of a lowermost container or crate in a stack are directly transferred towards the stacking edge parts in the corner regions of the container or crate. On the other hand, the container or crate has upright walls or wall portions between the corner regions which are located above the upright walls of a container or crate situated directly below said container or crate when stacked onto another container or crate, so that the forces in the upright walls of the container or crate in a stack can be directly transferred to the upright walls of a lower container or crate without bending forces being introduced in the upright walls or in the stacking flange.

Containers or crates according to the inventions can therefore be stacked to great heights when filled.

In a preferred embodiment the bottom of the container or crate is provided with ribs extending between kLe sprue k 25 point or sprue points of the container or crate and the stacking edge or stacking edge parts. This ensures during injection moulding of the container or crate a quick flow of material from the sprue point or sprue points towards the mould cavities for the upright walls. Due to these "flow channels" the mould cavities for the upright walls are filled in an early stage, which makes it possible that containers or crates with different heights can be manufactured in a mould with exchangeable side slides without changing the position of the sprue points.

The mould cavity for the bottom wall will not be filled too early which would results in a-very irregular shrinkage, and not too late with the chance of incomplete filling of the mould cavities for the upright walls and/or burning of walls parts.

The present invention will illustrated with respect to embodiments by means of the drawings: FIG. 1 shows a perspective view of a container or crate in accordance with the invention.

FIG. 2 shows a perspective view of a modified embodiment of the container or crate in accordance with the invention.

FIG. 3 shows a top view of the container or crate of fig. 1 or 2 on a smaller scale.

FIG. 4 is a cross section of the container or crate of fig. 3 along the line IV-IV.

FIG. 5 shows a detail of fig. 4 on enlarged scale.

FIG. 6 shows a detail of an upper part of the wall of a container or crate and a lower part of a like container or crate stacked upon each other.

FIG. 7 is a cross section of a corner region of the container or crate of fig. 3 along the line VII-VII on enlarged scale.

FIG. 8 shows a stack of similar containers or crates having different heights.

FIG. 9 is a bottom view of the container or crate of fig. 3.

Figure 1 shows a plastics container or crate comprising a bottom wall 1 and upright walls 2, which extend substantially perpendicular to the bottom wall 1.

The upper side of the plastics container or crate comprising a projecting circumferential upper flange 3, whilst the longest side of the container or crate comprises a projecting peripheral stacking flange 4 in the region of the bottom wall 1 and being integral with said plastics container or crate. The outer periphery of the circumferential upper flange 3 is situated substantially vertically above the outerside of the peripheral stacking ~r-

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-6flange 4.

The stacking edge 5 projects downwardly from below the bottom wall 1 of the container or crate, said stacking edge being spaced inwardly from the upright walls 2 so as to be received within the upper periphery of the upright walls of a like container or crate as is shown in figures 5 and 6.

Although the upright walls 2 in the plastics container or crate of figure I have the same height, it will be clear that said walls 2 may also have parts with a lower height.

In the region of the corners of the container or crate the upright walls 2 are provided with lower wall parts 7 which converge downwardly so as to terminate substantially above the stacking edge or stacking edge parts 5, as is shown in figure 7. The upright walls 2 between the corner regions extend substantially perpendicular to the bottom wall 1 over the total height of the upright walls.

Figure 2 shows a modified embodiment of a plastics container or crate according to the invention. The stacking flange 4 is connected with reinforcing ribs 8 upon the outerside of the container or crate.

Containers or crates according to fig. 1 or 2 can be manufactured with the same dimensions in horizontal direction but with different heights by using a so-called combination mould consisting of a bottom plate and a core, as well as exchangeable side slides which cooperate sealingly with the core and with the bottom plate and ich are adapted to the height of the container or crate. In this way it is possible to manufacture a "family" of mutually stackable containers or crates with different heights. The stack of such containers or crates with different heights is shown in fig. 8.

The use of containers or crates according to fig. 1 or 2 provides the benificial effect that the loading forces being exerted upon a lowermost container or crate 9 of a stack of such containers or crates are transferred directly towards the stacking edge parts 5 in the region of the a a a a *a 4 a 4 a 4a corners of the lowermost crate, placed for instance on a floor or a pallet surface. On the other hand, the forces in the upright walls 2 of a container or crate Tbove the lowermost container or crate 9 of a stack are directly transferred to the upright walls 2 of a lower container or crate without bending forces being introduced in the upright walls 2 or in the stacking flange 4, as will be clear from figure 6.

As a container or crate according to fig. 1 or 2 has converging wall parts I only in the regions of the corners of the container or crate the bottom surface area of the container or crate is as large as possible and nearly the same as that of a container or crate with the same dimensions in horizontal direction but without converging wall parts 7.

In a preferred embodiment of the container or crate according to the invention the bottom of the container or crate is provided with ribs 10 extending between the sprue points 11 of the container or crate and the stacking edge 2 of stacking edge parts 5, as is shown in fig. 7 and 9.

These ribs 10 reinforce the bottom wall 1 of the container or crate. On the other hand they assure that during injection moulding of the container or crate a quick flow of material from the sprue points 11 towards the mould cavities for the upright walls 2; so that the mould cavities for the upright walls are filled in an early stage. This makes it possible that containers or crates with different heights can be manufactured in a combination mould without changing the position of the sprue points.

The reference numerals in the following claims do not in any way limit the scope of the respective claims.

Claims (4)

1. A plastics container or crate comprising a bottom wall, upright walls at least partially extending substantially perpendicular to the bottom wall, a projecting circumferential flange at the upper side of the container or crate, a projecting peripheral stacking flange in the region of the bottom wall and a stacking edge or interspaced stacking edge parts projecting downwardly from below said bottom wall and spaced inwardly from the upright walls so as to be received within the upper periphery of the upright walls of a like container or crate, wherein only in the region of the corners of the container or crate the upright walls are provided with lower wall parts which converge downwardly so as" to terminate substantially above the stacking edge or stacking edge parts, and the upright walls between the corner regions extend substantially perpendicular to the bottom wall over the total height of the upright walls.

2. A plastics container or crate according to claim 1, wherein the bottom wall is provided with ribs extending between a sprue point or sprue points and the stacking edge or stacking edge parts of the container or crate.

3. A plastics container or crate according to claim 1 or 2, wherein the stacking flange is connected with reinforcing ribs upon the outer side of the container or crate.

4. A plastics container or crate substantially as hereinbefore described with reference to the drawings. 0000 0 0 00a o 0 0 0 00 A o o Dated this 5th day of March, 1990. F T, WAVIN B.V. By its Patent Attorneys DAVIES AND COLLISON