The choice of dock levellers is the first element in assembling a loading point.
Drawing on its long standing experience, CAMPISA has defined a series of key elements that your choice must take into account:
- Dock levellers with pivoting lip: the most low-cost.
At the touch of only one button, the dock leveller is raised to the maximum height, at which point the lip rotates to the extended position. When the button is released the dock leveller comes down slowly to join up with the vehicle floor, where it forms an inert bridge that follows the rising and lowering of the vehicle as the trolleys pass over.
After loading, by pressing the same button, the dock leveller lifts up and the lip closes at the same time. If the button is released before reaching the maximum lift point, the dock leveller slowly lowers to the resting position with the lip closed inside the lip-stop blocks, ensuring a crossing with full load at floor level.
The lip can have different depths depending on the construction system, but the important factor is how much the lip protrudes from the edge of the dock when it is extended.
- Dock levellers with telescopic lip: the more expensive by around 30% compared to the previous ramps, but offer greater flexibility of use.
By pressing the “lift” button the dock leveller is raised; when it reaches a few centimetres above the vehicle floor, release the lift button and press the “lip out” button, when it has safely overlapped the floor (around 15cm), release the button. The dock leveller has joined the floor to form an inert bridge that follows the rising and lowering of the vehicle as the trolleys pass over.
Once the loading is complete, press “lift” to lift the dock leveller just enough to free it from contact with the floor, in all cases above the floor level. By pushing “lip in” the lip retracts completely, and by releasing the button when the dock leveller has finished its journey it will return to the rest position, ensuring a crossing with full load at floor level.
The option is available for the command ” dock leveller automatic return to rest”.
The lip can have an extension of 500mm or 1000mm, the latter used only in special cases such as recessed docks for cold stores.
DOCK LEVELLER LENGTH
To be chosen based on the height of the dock and the type of operating vehicles used:
- Pallet trucks: recommended maximum gradient 4%.
- Forklift trucks: recommended maximum gradient 8%.
NOTE: the maximum gradient of 12.5% set by European Standard EN 1398 is the maximum non-slip gradient for people.
The height of the dock is a critical factor, because if the dock is high it is a hindrance when joining up floors beneath dock level, given that the sides of the pit create bulk that causes blockage at times.
But if the dock is lower and vehicles manage to reverse over the dock, damage occurs to the equipment and to vehicles. For more on this subject, see the “bumpers” page.
- For semi-trailers and large trailers, a dock height of 1,200mm is recommended. Floors that have a height of between around 900mm and 1500mm with maximum gradients below the 12.5% set by Standard EN 1398, can be connected with 2500mm long ramps.
Lower gradients, more suitable for electric pallet trucks, are obtained with ramps 3000mm in length.
- For medium size trailers and “city vehicles” a dock height of 1.100 mm is recommended.
DOCK LEVELLER WIDTH
It must be “as close as possible to the width of the floor of the connecting vehicle”, up to 25cm less than the width of the vehicle floor:
- For semi-trailers and large trailers, dock levellers 2200mm wide, with two side flaps automatically reducing the lip by 130-180mm on each side, in case of connecting narrower vehicles.
- For vehicles with an external width of 2300mm, 2000mm wide dock levellers with two side flaps automatically reducing the lip by 130-180mm on each side in case of connecting narrower vehicles.
DOCK LEVELLER CAPACITY
Capacities are standardized in consideration of the maximum ‒ even if occasional ‒ load. Standard EN 1398 sets out that the capacity of the dock leveller is calculated on only one axis of the lifting trolley, on two wheels 1 metre apart.
Other types of calculation, such as for example the uniform distributed load (two/three times greater than the concentrated capacity) are not relevant to the type of use that will occur. The most standardized capacity is of 6 concentrated tonnes; lower capacities bring insignificant savings. For larger capacities or faster transit (the requirement allows crossing at 5 km/h) dock levellers with a concentrated capacity of 9 tonnes are recommended.
NON-STANDARD LOADING DOCK LEVELLERS
- Particular loads require special dock levellers. For example dock levellers 4 metres and even 5 metres in length to connect the 1.2m high dock to the floors of short vehicles with a height of only 60cm from the ground. Dock levellers of this length enable electric pallet trucks to operate.
- For very humid areas and cold stores, hot-dip galvanized dock levellers are recommended.
- For cold stores the recessed dock system is recommended, in which the dock leveller remains closed inside the building when not in use, with the sectional door closing in front of the dock leveller. In this case the dock leveller is telescopic with the lip protruding 1 metre.