During travelling, weight, inertia and friction cause the load to remain where it was placed, if it were not for the acceleration of the vehicle during moving off and during the journey, braking or changing direction, such as cornering. They move the load from its original position. Therefore, a counteracting force is required that, – at the same magnitude – secures the load. The relationship between the normal force (weight or pressure) and the friction, known as the friction combination, is defined by the sliding friction coefficient (μ) (pronounced ‘mu’).
vertically presses the load onto the loading surface.
attempts to keep the load in its present position and acts against the acceleration, braking and changes in direction of the vehicle.
The friction force
prevents or reduces displacement of the load. Its effect is influenced by the surfaces of the load and loading surface.
Friction – the retardation
Each surface – even if it appears smooth – has irregularities, small "mountains" and "valleys". When two surfaces are pressed onto each other, they catch and make relative movement difficult. This resistance is reflected in the coefficient of friction μ [mü]. The smaller the value, the less the resistance. When stationary, the resistance is greater than when the objective is moving. When securing loads, this dynamic coefficient of friction is taken as a basis because, due to vibration during travelling, it cannot be presumed that the load is stationary.