Pallets are commonly used in situations where various types of loads are stored or transported. Pallets are available in many different designs. The traditional pallet is made of wood and comprises a load deck on which the load is intended to be placed. To allow the pallet to be lifted, the pallet is provided with two or three parallel stringers on which the load deck rests. The stringers comprise a longitudinal lower board and two or more pallet-deck spacers between said board and the load deck. In this way, a space is formed between the underside of the load deck and the ground, or between the top side of the board and the underside of the load deck, for access by forks of a fork-lift truck or the like. There are pallets of a similar design that are made of plastic or metal.
Pallets not made of wood are becoming more common now. These pallets have advantageous properties such as a longer useful life and less risk of damage and are more hygienic compared to pallets made of wood. For example, these pallets can be made of plastic or metal. However, there are also disadvantages or difficulties in constructing pallets from plastic or metal. For example, when constructing pallets from metal, it is necessary to use relatively thin plate in order to ensure that they are sufficiently light in weight and that they have a reasonable price in relation to their service life. However, a pallet made from thin plate can make handling difficult, since the pallet, compared to a pallet made from thicker plate, is not as durable when handled by trucks, for example. A pallet made from thin plate is quite easily damaged during such handling.
WO 2007/141154 describes a typical pallet made of metal and having a plurality of stringers and a load deck. The stringers are tubular and are formed in one piece with those parts of the load deck that connect the stringers to one another. The side surfaces of the stringers have punched-out openings through which a fork can be introduced in order to lift the pallet.
Depending on how the pallet is intended to be used, it will be exposed to different kinds of loading scenarios. If the pallet is intended to be used in a uniform and well-defined manner, it is possible to construct the pallet for a limited number of loading scenarios. An example of such a use is when the pallet is to be owned by a company that intends to use the pallet in one way or in a limited number of different ways. If the pallet is intended to be used in an open system in which pallets are interchanged, account has to be taken of a large number of different loading scenarios.
A typical loading scenario is one in which a pallet is placed in a pallet stand. A pallet stand in most cases has a front and a rear transverse beam for supporting the pallet. If a heavy load is placed on a pallet positioned in a pallet stand, the pallet tends to bend downwards between the transverse beams. This downward bending can lead to permanent deformations or, in the worst case, to the pallet breaking and falling from the pallet stand.
Another typical loading scenario is when pallets are stacked on top of one another. When stacking pallets, a superstructure is almost always used that generally comprises one or more pallet collars placed on top of one another. The upper pallet is placed such that it is supported by the superstructure. If a pallet with U-shaped stringers (as are common in a pallet made of metal) is stacked with a heavy load, the sides of the stringers (the legs of the U-profile) bend outwards.
Similar deformation also arises when a pallet with U-shaped stringers (as are common in a pallet made of metal) stands on the ground and is loaded with a heavy load.
Another typical loading scenario is when the pallet is loaded with an uneven or unbalanced load. This can lead to uneven loading of the pallet, which in turn can cause the central part of the stringers to sag. Stacking a pallet on top of a pallet with an uneven load can create deformation of this kind even at relatively low loads.
It may thus be said that there is a need for a pallet with improved load resistance in at least one of the described loading scenarios.
In addition, it is important that the pallet is sufficiently resistant to collisions and impacts, which it can be exposed to from trucks or other equipment used for lifting and moving pallets.