_j The present invention relates to a tractor truck, particularly intended for moving goods receptacles or so- f called containers, and includes at least one front axle, one or more driving axles , a frame and a load coupling device at 5 the rear portion of the vehicle for connecting the vehicle to the load or vehicle that is to be towed.

At ports , air fields and railway stations there is a great need of simple and effective means for moving con¬ tainers, semitrailers etc. Amongst other things, the 10 development in ports throughout the world is consequently towards increased use of so-called roll on- roll off hand¬ ling, which is effected by the load being rolled off and on ferry-like ships via special ramps. The ships are expensive and there is a strong wish for rapid handling and short 15 turnaround times in ports, which makes for great interest in effective load handling methods .

There is a known tractor truck, which is described in the Swedish published specification 412 571, and which may be used for moving containers on board ship and in ports, 20 and which gives good manoeuverability. The drawback with this known tractor truck is that its driving wheels are turnable in relation to the vehicle chassis, which makes transmission very complicated and also results in problems with the vehicle tires, since the driving wheels will be 25 relatively small aηd therefore very highly loaded.

The present invention has the object of providing a tractor truck primarily intended for moving wheeled con¬ tainers or semitrailers and which is more stable and flex¬ ible, as well as cheaper to manufacture than known tractor ^' 30 trucks of this kind.

The inventive tractor truck is characterized in that the vehicle is turnably articulated at the load coupling device by means of a vertical shaft, said device being in¬ tended to be rigidly coupled to the load in the horizontal 35 plane, while the vertical shaft is connected to torque- providing means adapted to turn the vehicle in the horizontal plane in relation to the load coupling device, thus to steer

the vehicle.

The advantage with a tractor truck in accordance with the invention is that together with the container or semi¬ trailer it forms an inflexible rig which gives the driver a better view. Furthermore, the inventive vehicle cannot "jack-knife" for heavy loading, which also prevents the vehicle from losing steering ability due to lifting of the front wheels , as can be the case with known tractor trucks , e.g. those with a bearing plate or so-called "fifth wheel". By the inventive vehicle connected to the wheeled load hav¬ ing a large support surface there is obtained better lateral stability than with known vehicles of this kind, which is of great importance in transporting large loads . The vehicle with load furthermore has a very small turning circle and good manoeuve ability, which is essential for example in the confined spaces in question on a ship.

The invention will now be described in detail in the following while referring to the accompanying drawing on which the Figure is a schematic side view of an embodiment of a tractor truck in accordance with the invention.

The tractor truck 1, illustrated on the drawing, is connected to a wheeled goods receptacle or container 2 via a coupling device 3 with a yoke , which is coupled to one end of the container 2. At its other end the container is provided 'with removable wheels 5. The device 3 is joined to the vehicle frame 6 via a vertical shaft 7 coupled to an unillustrated torque moto , intended to turn the vehicle , and thus steer it when the container 2 is coupled. The vehicle then rests on the substructure with the aid of both driving axles 8 and 9, while the front axle 10, which is also the steering axle, is lifted from the substructure. The front axle must be steerable, however, so that the vehicle may be driven without load. The front axle may be steerable, either conventionally, or with the aid of so- called "waist steering". The tu nable attachment between the load coupling device and the vehicle frame may be stiff or articulated in the vertical plane. The device 3 may be raisable and lowerable, e.g. with the aid of a lifting cylinder or lifting arm, or the wheels 8,9 may be raisable

and lowerable in relation to the vehicle frame.

Moving the container 2 is accomplished by the vehicle 1 being driven in towards the container, the vehicle and container being afterwards coupled together with the aid of the coupling device 3. The container end connected to the yoke H is then lifted by the device 3 being raised, or by the vehicle driving axles 8,9 being thrust out from the vehicle frame 6. To reduce wheel scrubbing the front axle 10 is raised in the case where lifting the container is done with the aid of the device 3. The vehicle may then be propelled forwards or backwards by the drive on axles 8,9 and the vehicle may be steered with the aid of the torque motor coupled to the vertical shaft 7. It should be noted that it is not necessary to raise the front axle 10 for driving the vehicle.

The vehicle does not need to have two driving axles , as in the illustrated embodiment, but may only have one axle or more than two should this be found necessary. The front axle 10 may be li ^' fted with such as pneumatic cushions from which the air can be evacuated, or by the entire vehicle being pivotable about a horizontal axis . In some cases , the steerable front axle may be dispensed with entirely, e.g. if the vehicle is centrally articulated or can be braked differently on its right- and left-hand sides . Hereinbefore there has been described a special embodiment of a tractor truck with a coupling device which is rigidly connected in the horizontal plane to the goods receptacle that is towed. The invention is not restricted to this special embodiment, and it can include different variations within the scope of the claims. For example, the rigid coupling to the load in the horizontal plane may be achieved with the aid of a so-called "swan neck" with a horizontal tongue which is inserted in a recess in a special semitrailer on which the load rests .