The bumpers absorbs the impact of the docking vehicle as to preserve the dock and the dock leveller.
If the slope of the court is of the 2% outwards, the bumper is not damaged by the vertical movement of the vehicle under load. If the slope of the court is inwards, against the dock, there is a very strong friction during the loading, that demands stronger bumpers, sometimes with the optional steel cover.
In case the vehicles overlap the dock level, every type of bumpers is destroyed when the vehicle is loaded and it lays onto the dock. In this case it is indispensable to install bigger and stronger bumpers and with raising device.