Mobile yard ramps are specifically designed to provide ground to dock ramp access to high dock warehouses or trailer beds. They do not require special preparation to operate allowing for loading/unloading operations to be performed without construction of a traditional concrete ramp. All DoorHan ramps have a similar principle of operation, i.e. a ramp is lifted by a mechanical or hydraulic drive, equipped with safety system, and is easily transported to the warehouse dock or the trailer with a fork lift. If a ramp has legs then it is set on them, if the trailer bed is used as a support for the ramp then it is lowered onto it. After the loading/unloading operations have been completed the ramp is raised and transported to the place of storage.