Paul Foot | Strengthening corrugated cardboard for storage and transport

Paul Foot, from intellectual property firm Withers & Rogers, discusses at a new patent for corrugated packaging from DS Smith.

Paul Foot, patent attorney, Withers & Rogers, a leading European intellectual property law firm
Paul Foot, patent attorney, Withers & Rogers, a leading European intellectual property law firm

The cost of production is always a focus when manufacturing packaging for goods transportation. This month’s patent relates to the design and manufacture of cardboard trays, such as those used to store and transport various products, particularly fruit and vegetables.

The trays are typically manufactured from corrugated cardboard which is lightweight, relatively strong and readily recyclable. These trays are manufactured in large volume, and the production process is streamlined as far as possible to minimise inefficiency and cost. Each tray is therefore ideally made out of a single blank which is then folded and locks together via a series of tabs and slots.

In use, multiple trays are often stacked on top of each other and in this case each tray is required to be sufficiently strong and stable to support the load of those above it in the stack. Although the trays themselves are often lightweight, the contents can weigh many kilograms. The bottom tray in the stack, therefore, must be able to withstand significant compressive loading.

Typically, an insert is added in each corner of the tray or, where manufactured from a single blank, an additional panel extends along the length of each side or end. This provides a strengthened flat top and bottom stacking surface. Either solution adds complexity and therefore cost to the tray.

One of Europe’s largest corrugated board packaging manufacturers, DS Smith, has recently been granted a patent (GB 2504067) which addresses this problem. The patent provides a tray with reinforced corners which is made from a single blank of corrugated cardboard.

The tray has reinforcement sections located in each of the corners in the form of a prism, which provides a secondary wall thickness. Flat stacking surfaces are provided in each corner of the tray above the prismatic sections, which are twin thickness triangles formed of a diagonally folded square section of the blank material. The design is simple and compact and the stacking surfaces help avoid significantly reducing the capacity of the tray. There are no additional panels at the sides, therefore providing minimal intrusion at the edge line of the tray and maintaining ease of access to the contents.

The blank from which the tray is constructed is almost a complete square or rectangle of sheet material, resulting in minimal wastage. The box is constructed by folding and self-locking tabs that hold the assembled tray together. This therefore results in a potentially stronger tray with an enhanced ease of manufacturing.

Of particular note to DS Smith, which of course combines its packaging business with a network of paper recycling centres, is the ease of flattening the tray to form a single flat sheet. This minimises bulk and mess on the return trip, as well as the lack of staples or adhesive to compromise the purity of the waste stream.

Unsurprisingly for a company of its size, DS Smith holds patents across a broad range of categories. Other recent applications include retail ready paperboard packaging with an integrated product “pusher” which brings the product to the front of the box, liquid valves, pallets and even furniture produced from corrugated board!

Paul Foot is a partner and patent attorney at Withers & Rogers

Withers Rogers Corrugated