Many products that are manufactured and ultimately sold for and used by an end user--whether it be a company or an individual--must be shipped at least once from where the product is produced to where the product is stored, consumed or used. In actuality, a product may be shipped several times, such as from the manufacturer to the distributor, to the warehouse, then to a retail store and ultimately to an end user. It is of course necessary that the product be protected during this time of shipping and storage so that it ultimately reaches the end user in an unharmed condition.
A very widely used--and indeed almost universally used--packaging system for protecting products that could be easily damaged during shipping and storage--typically items such as electrical or electronic appliances--consists of a cardboard box with packing material interposed between the product and the inner walls of the cardboard box. The packing material displaces the product from the cardboard box around all sides of the product so that almost any impact on the cardboard box will not directly reach the product. Further, the packing material preferably keeps the product in a fixed relation with respect to the cardboard box so that the product does not move around within the cardboard box. In order to keep the product in fixed relation within the cardboard box, it is necessary that the product fit snugly within the packing material and also that the packing material fit snugly within the cardboard box.
Two types of forces may be encountered by a packed product during shipping and storage. Firstly, there is movement of the cardboard box, which may be quite sudden or severe. This sudden or severe movement would cause the cardboard box to experience related accelerative and decelerative forces. Correspondingly, the product inside must move along with the cardboard box, and if there is no cushioning between the product and the cardboard box, the product would experience roughly the same accelerative and decelerative forces experienced by the cardboard box. Secondly, there are impact forces that can occur as a result of a sudden impact with the cardboard box by another object. Again, the accelerative forces are transmitted through the box to the product and must be cushioned in order to protect the product from potential damage.
In order that forces experienced under various shipping and storage conditions are not transmitted to the product, it is necessary to have some sort of packing material that will deform to some degree in order to absorb the impact forces slowly and evenly over a period of time. This will spread out the absorption of the energy of the impact forces such that the full impact forces will not be transmitted to the product. Resultingly, a smaller force will be transmitted over a longer period of time. The product will not experience as great a force, and therefore will be less likely to be damaged.