The present invention relates to a method for loading a lengthy object, such as a transport container, onto a vehicle and for unloading of the object from the vehicle by using a winch, or equivalent means, mounted on the vehicle, by means of which winch the object is pulled onto the chassis construction, or equivalent, of the vehicle.
The invention also relates to a vehicle designed for implementation of the method mentioned above, which vehicle is provided with a winch for pulling the object onto the vehicle.
A method is previously known by means of which a vehicle can be loaded by using a so-called transfer truckbed system. Such a system comprises several loose truckbeds, which can be pulled onto the truck by means of a winch. It is necessary to raise the dumping mechanism to some extent in order that the truckbed should not be jerked very strongly when the center of gravity of the truckbed is shifted onto the vehicle frame. This method has been applied to the loading of so-called semi-long containers (e.g., 20 ft), and is marketed under the trade name "Multilift". A drawback to this system is the steep loading angle, due to which the goods inside the container can become disarrayed. In order to avoid this, it is a known procedure to use cranes mounted on the vehicle. These, however, increase the overall length of the truckbed to an unreasonable extent.
A particularly serious problem consists of the loading and unloading of so-called long containers. By long containers are meant 12 meter long (40 ft) containers, by means of which a major part of freight traffic is transported today. Loading of these long containers onto a vehicle by using, e.g., the method known under the trade name "Multilift", is impossible. This is due to the circumstance that the construction of long containers does not stand such handling.
For long containers, it is a known procedure to provide the vehicle with cranes mounted on the truckbed. This, however, results in the drawback that the overall length of the vehicle exceeds the overall length permitted by many statutes. Another drawback is that, since the cranes mounted on the truckbed increase the totoal weight of the vehicle considerably, the maximum total weight permitted by statute is easily exceeded. There are vehicles of this type, e.g., in Finland, but they are only allowed to operate under exceptional permit within the area of the City of Helsinki.
Another method for loading and unloading long containers, in fact the only practical one available at present, is the use of large fork-lift trucks and straddle carriers. These are, however, available only in a few places. This results in the circumstance that a large container is usually not unloaded from the vehicle at the customer's premises, but the vehicle remains waiting until the load in the container has been unloaded. Of course, it is uneconomical to make expensive transport equipment stand unnecessarily during the unloading of the container. As a matter of fact, the whole idea of container transports then loses much of its meaningfulness.
Some of the drawbacks of the vehicles meant for the transport of long containers are mentioned above. Owing to cranes mounted on the truckbed, the overall length and frequently also the total weight of the vehicles exceed those permitted by statute. Under these circumstances, they cannot be used without particular permit. Consequently, many vehicles include systems of handling containers that are highly complicated and expensive.
On the other hand, if the vehicles have no handling equipment of this type and only external loading and unloading aid is utilized, the standing times of the vehicles become unreasonably long.