NZ280093A - Injection moulded plastics crate with hollow beam section on underside - Google Patents

Description

New Zealand No. International No. 280093 PCT/ TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 26.09.1994; Complete Specification Filed: 26.09.1995 Classification:^) B65D1/22.42 Publication date: 24 November 1997 Journal No.: 1422 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: A crate Name, address and nationality of applicant(s) as in international application form: GEORGE WESTON FOODS LIMITED, an Australian company of Level 20 Tower A -Zenith Centre, 821 Pacific Highway, Chatswood, New South Wales 2067, Australia 280 0 9 3 Patents Form No. 5 Our Ref: JB205411 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION! A CRATE • > V L<<» o\ % % We, 6EOROE WESTON FOODS LIMITED, an Australian company of Level 20 Tower A - Zenith Centre, 821 Pacific Highway, Chatswood, NSW 2067, Australia, hereby declare the invention, for which We pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: PT0512580 (followed by page la) la 28 0 0 A CRATE The present invention relates to crates, and in particular to crates manufactured from plastics materials formed through injection moulding.

Injection moulding has been used for many years in the manufacture of many plastics products and in particular crates used to carry consumer articles such as bread, milk and the like. Such plastics crates are highly desirable in the food industry because they are relatively light weight and therefore do not significantly contribute to transportation costs which often account for a major portion of the retail price of such products. Also, because they are manufactured of plastics materials, they can be readily cleaned and therefore satisfy health requirements.

Injection moulding has also been used to make other articles such as furniture and the like.

Where the injected moulded article is of reasonable size and it is necessary for the article to support a reasonable mass, various configurations are well known to provide structural integrity to the article. Accordingly, it is not uncommon for a plastics crate to include ribbing, webs and/or cantilever type beams which act to provide rigidity and strength to the structure.

Specific difficulties with such arrangements arise where the crate or other article is substantially planar such as crates used to carry a number of loaves of bread, for example. In such instances, whilst the structure of the cantilever beams and ribbing can well be sufficient to support the weight of the goods being carried, the beams and ribbing are generally insufficient to prevent twisting of the crate due to its shallow height and the like. A lack of torsional strength makes such crates difficult to use in mechanised packing and conveying systems. When previously crates have been used r-. T with such systems, their life time is substantially reduced due to genera^y-jnlierent - ^ rough handling caused by the machinery. (j ^ It is an object of the present invention to substantially overcor these difficulties through provision of an alternative injection moulded crate.

XfoIIowed by page 2)' {N:\libool00319:LDP 28 0 09 In accordance with one aspect of the present invention there is disclosed a crate formed from the injection moulding of plastics, said crate having a structure formed from a plurality of integrally moulded support beams, characterised in that said crate comprises at least one hollow beam section integrally formed with said structure during said injection moulding.

In accordance with another aspect of the present invention there is disclosed a method of forming a crate using the injection moulding of plastics materials, said method including the step of injecting gas into a beam section during curing of said plastics materials to form at least one hollow beam section.

A preferred embodiment of the present invention will now be described with reference to the drawings in which: Fig. 1 is a plan view of a bread crate of the preferred embodiment; Fig. 2 is an end elevation view of the crate of Fig. 1; Fig. 3 is an inverse plan view of the crate of Fig. 1; Fig. 4 is a front elevation view of the crate of Fig. 1; Fig. 5 is a partial cross section along the lines V-V of Figs. 1 and 3; and Figs. 6 and 7 are side and end views respectively of the crate being transported by a chain conveyor.

With reference to Figs. 1 to 4, a bread crate 1 is shown which includes a front wall 2, a corresponding rear wall 3, and side walls 4 and 5 that are substantially identical to each other, thus forming a rectangular, and preferably oblong, shape. The walls 2 to 5 are substantially upstanding and therebetween define a product plane 6 in which goods can be carried. In this case, the crate 1 is sized to carry ten (10) loaves of bread. Each of the walls 2 to 5 are of substantially traditional structure and substantially correspond to the construction shown in Australian Design Re^jB^tion No. 117984 by the same applicant. fl* As seen in Figs. 1 and 3, the product plane 6 includes 1 nuiA&rof triangular shaped apertures 7 positioned adjacent the walls 2 to 5, and a nunttterpi diamondr V E 0 shaped apertures 8 each having a cruciform-shaped integral web 9 interconnecting the [N:\liboo|00319 :LDP 28 0 09 four corners of each diamond shaped aperture 8. The provision of the apertures 7 and 8 reduce the weight of the crate 1.

Referring specifically to Fig. 3, formed beneath the product plane 6 is an array of supporting structures which act to prevent the crate 1 from failing when loaded with goods. The supporting structures include a plurality of ribs 10 which extend perpendicularly from each other beneath the product plane 6 to increase the vertical moment of inertia of the plane 6. As seen, the ribs 10 run in parallel sets of intersecting paths between adjacent ones of the apertures 7 and 8. This forms a honeycomb type support structure beneath the product plane 6. Also shown are two cantilever type beams 11 which interconnect diagonal corners of the crate 1 and intersect beneath the centre of the product plane 6. Each of the beams 11 comprises two parallel ribs 12 and a number of braces 13 inclined to, and interconnecting, each of the parallel ribs 12.

Whilst the structures described above provides strength to the crate 1 in order for it to support its load, they do not contribute substantially to the torsional strength of the crate 1. In particular, because the front and rear walls 2 and 3 include a cut out portion 14, seen in Fig. 4 which significantly reduces their height compared to that of the side walls 4 and 5, the front and rear walls 2 and 3 detract from the torsional rigidity of the crate 1.

In order to increase torsional rigidity of the crate 1, two hollow beam sections 15 are provided beneath the product plane 6 and immediately adjacent each of the side walls 4 and 5. The beams 15 are formed in a hollow manner which provides a structure that is rigid in both the horizontal and vertical planes. In particular, the beams 15 are formed by injecting gas into the mould as the plastics material cures. In this manner, a number of air holes 16 remain in the beams section 15 on completion of manufacturing of the crate 1. The gas can be air, but is preferably nitrogen^ Turning now to Fig. 5, a more detailed view of the beam in cross section and is seen to include two sides 17 extending subst perpendicularly from the product plane 6, and an interconnecting rot tafcedee^/ [N:\libool00319:LDP "4~ 28 0 0 9 3 18 that substantially closes the beam section IS to form a hollow. As schematically illustrated by the shading in Fig. 5, the hollow beam sections IS and surrounding portions of the crate 1, including the periphery of the product plane 6 and the lower portions of the side walls 4 and 5, are manufactured from substantially thicker section plastics material which offers greater rigidity and strength at those locations which are, in practice, the areas most subject to stress during use.

Gas injection is used to form the beam sections 15 for a number of reasons.

Firstly, by having a hollow beam 15, the weight of the crate 1 is reduced compared to having a solid beam, as well as reducing the amount of plastics material required to form the crate. Also, the gas injection permits elimination of the plastics material sinking or shrinking during curing which can occur at a location other than at the injection point in a manufacturing assembly. Accordingly, in manufacture, once gas is injected to form the hollow sections 15, the gas inlet holes 16 can be left open so that atmospheric pressure is applied to both the interior and exterior surfaces of the hollow beam section 15.

Turning now to Figs. 6 and 7, the crate 1 is shown in use in a manufacturing line, for example in a bakery. A chain conveyor 20 which generally comprises two chains 21 is configured approximately 20 mm above the floor level of the manufacturing facility. Only one of the chains 21 is shown for the purposes of clarity.

At periodic intervals along each of the chains 21, an upstanding tab 22 is provided which is configured to engage with the hollow beam section 15 so as to carry the crate 1 along the conveyor 20.

The provision of the flat side 17 and rounded end section 18 of the hollow beam sections 15 permits firstly the tab 22 to cleanly engage the beam section 15 so that it may be carried by the conveyor. Also, the rounded section 18 acts to reduce friction of the crate 1 when sitting on the chain conveyor 20 whilst allowing smooth transfer of the crate 1 from one chain conveyor to another. This associated with prior art bread crates where the ribs 10 and cantil inclined to become caught in mechanical chain handling systems.

|N;\liboo)00319:LDP eliminate jf ^ evjffpabeams 28 0 0 The foregoing describes only one embodiment of the present invention and modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.

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Claims (14)

-6- SSOogj What we claim is:

1. A crate formed from the injection moulding of plastics, said crate having a structure formed from a plurality of integrally moulded support beams, characterised in that said crate comprises at least one hollow beam section integrally formed with said structure.

2. A crate as claimed in claim 1, wherein said crate is substantially rectangular in shape and comprises at least two of said hollow beam sections on an underside of said crate parallel to corresponding sides of said crate.

3. A crate as claimed in claim 1 or 2, wherein said crate is oblong in shape and has two of said beams, each said beam being arranged parallel and adjacent to a corresponding shorter side of said crate.

4. A crate as claimed an claim 1, 2 or 3, wherein each said beam comprises two sides extending from a plane of said crate, and a distal edge interconnecting said sides to form a substantial hollow therebetween.

5. A crate as claimed in claim 4, wherein said beam sides extend substantially perpendicularly from siiid plane, and said distal edge is rounded.

6. A crate as claimed in claim 4 or 5. wherein said distal edge includes at least one hole resulting from an gas injection process used to form said crate.

7. A crate as claimed in claim 6 wherein said gas is air.

8. A crate as claimed in claim 6 wherein said gas is nitrogen.

9. A crate as claimed in any one of the preceding claims wherein said hollow beam sections) is/are configured to be engaged by at least one upstanding tab of a chain conveyor apparatus used to transport said crate.

10. A method of forming a crate using the injection moulding of plastics materials, said method including the step of injecting gas into a beam section during curing of said plastics materials to form at least one hollow beam section.

11. A method as claimed in claim 10 wherein said gas is air.

12. A method as claimed in claim 10 wherein said gas is nitrogen. I.J^^^TEN7^0FFICE 1 n SFp -jc?97 -7- 28 0 0 9 3

13. drawings.

14. drawings. A crate substantially as described herein with reference to the A method of forming a crate as described herein with reference to the GEORGE WESTON FOODS LIMITED By Its Attorneys BALDWIN. SOW & ENDOFCLAIM8 [N-Wtboo!00319-LDP