The present invention relates to a three-axle semi-trailer with a lowered chassis and with a tilting tank.

Semi-trailers are known, consisting of a chassis provided, on the rear, with one or preferably more axles and, on the front, with a pin which may be hooked to a fifth-wheel coupling belonging to a conventional road tractor.

The semi-trailer may be configured in various manners and, in particular, it may be provided for the transport of containers or of swap bodies, as well as of tanks or of reservoirs, and may be of the fixed or even of the tiling type, so as to unload the bulk goods contained therein.

In particular, semi-trailers are known defined as "low bed semi-trailers". They are generally used for the transport of loads which develop in height and require a loading bed placed at a lower level with respect to the plane of the fifth-wheel coupling of the tractor, so as not to exceed the maximum height of the vehicle, such as it is imposed by road transport regulations.

Generally, the chassis of a low bed semi-trailer comprises a front part, which is provided with a pin for the hooking and the articulation to the fifth-wheel coupling of the tractor, and which, therefore, must have a height from the ground substantially equal to that of the fifth-wheel coupling, and a rear loading bed which is placed at a height lower than that of the front part and which is joined to the latter by means of structural connecting elements.

Lowered semi-trailers intended for the transport of bulk goods are also known; they are provided with a tank (box), which is articulated to the chassis of the semi-trailer and is provided with means for the rearward tilting thereof so as to unload the goods from the rear side thereof. This solution is widely diffused, but has a limitation in the uniqueness of the use of the semi-trailer which, given the presence and the shape of the tank, may be substantially used only for the transport of bulk goods and this may result in a non-optimal utilization of the route that the vehicle must perform in transfers from one place to another.

For example, AU2008237592 shows a three-axle semi-trailer comprising a chassis with a lowered portion, and a tilting tank at least partially supported by said lowered portion.

It is the object of the invention to provide a semi-trailer with a lowered chassis and with a tilting tank which offers truck drivers the opportunity of a better utilization of the routes they have to take.

In particular, it is the object of the invention to provide a lowered semitrailer with a tilting tank which, in addition to being used for the transport of bulk goods, may also be used for the transport of containers, regardless of the standardized size thereof. In fact, known standardized containers (ISO containers) are known to have a length of twenty feet, thirty feet, forty feet or forty-five feet and are provided, at the vertices thereof, with so-called corner blocks, which may be removably engaged with corresponding locking devices or twist locks, fastened to the semi-trailer in corresponding positions.

It is another object of the invention to provide a semi-trailer which, during road driving, may comply with the regulations on "legal" transport, i.e. , on "oversize" transport.

It is another object of the invention to provide a semi-trailer which allows normal road transit even with a load which in itself may be unbalanced.

It is another object of the invention to provide a semi-trailer which has an alternative characterization, both in constructive terms and in functional terms, with respect to the conventional ones.

It is another object of the invention to provide a semi-trailer of simple and low-cost construction.

All these and other objects which will become apparent from the following description, are achieved in accordance with the invention by a three- axle semi-trailer with a lowered chassis and with a tilting tank as defined in claim 1 .

The present invention is hereinafter further clarified in a preferred embodiment thereof and in some operational variants shown merely by way of explanation and by way of indication with reference to the accompanying drawings, in which:

Figure 1 shows, in side view, a lowered semi-trailer in accordance with the invention,

Figure 2 shows a plan view thereof,

Figure 3 shows an exploded perspective view thereof,

Figure 4 shows a perspective view thereof, when loaded with a thirty-foot container,

Figure 5 shows a side view thereof,

Figure 6 shows a side view thereof, with the tank and the container tilted for unloading the bulk goods contained therein,

Figure 7 shows a perspective view of the tank with a tie-rod for the connection to the two sides thereof,

Figure 8 shows a perspective view of the detail of Figure 4 relating to a clamp for tying the container to an edge of the tank, Figure 9 shows a side view of the semi-trailer loaded with a forty-foot container,

Figure 10 shows a side view thereof, when loaded with two twenty-foot containers,

Figure 1 1 shows a side view thereof, when loaded with a twenty-foot container and with a ballast,

Figure 12 shows a same view thereof as in Figure 1 1 , but with a container in the inclined condition, and

Figure 13 shows a same view thereof as in Figure 1 1 , in an embodiment variant,

Figure 14 shows a same view thereof as in Figure 9, with the tank and with the forty-foot container tilted for unloading the bulk goods contained therein.

As shown in the Figures, the semi-trailer in accordance with the invention comprises a chassis 2 with two parallel struts 4 spaced apart from one another by a plurality of cross-members 6.

Each strut 4 is actually formed by two parallel straight sections, a shorter front one and a longer rear one, connected to each other by an inclined section, so that the chassis 2 has no planar development but has a front portion placed at an upper level and a rear portion placed at a lower level. For this reason, the semi-trailer using a chassis with this configuration is also defined in the technical jargon as "gooseneck".

The front portion thereof is placed at a level compatible with the hooking of a conventional articulation pin 8 thereof to the fifth-wheel coupling of a conventional tractor (not shown) for road transport. Conveniently, it is pointed out that "rear" hereby means a part, zone or direction which, in contrast to a "front" part, zone or direction, is more distant from the pin 8. In particular, the pin 8 for hooking the semi-trailer to the fifth- wheel coupling of the tractor is provided at a front zone of the chassis 2.

Furthermore, unlike all the cross-members 6 which connect the two struts 4 to each other and which have a length equal to the distance between them, a cross-member 6', placed in the front part of the chassis 2, extends beyond the struts 4 and is provided, at the ends thereof, with two conventional twist locks 10 for engaging the conventional corner blocks 12 of a forty-foot ISO container 14, as it will be better described below.

The rear portion of the chassis 2 is placed, as said, at a lower level with respect to the front part and has three axles 16 applied, of which the rear one is preferably placed at a distance from the central axle greater than the distance between said central axle and the front axle.

Furthermore, the rear axle may advantageously be of the steering or of the self-steering type.

Advantageously, the axles 16 may be mounted on an axle-carrying structure which is longitudinally slidable on said chassis 2 and may be locked in a plurality of pre-set positions, as described in PCT/IB2017/053482, the content of which is to be intended as entirely incorporated herein by reference.

The rear part of the chassis 2 is arranged to receive a tank 1 8 which, preferably, is of the type intended to mainly receive bulk goods, similarly to the conventional tanks mounted on any semi-trailer.

Conveniently, the tank 18 is articulated to the chassis 2 at an articulation shaft 19 (see Figure 3) and may be tilted about the articulation axis thereof in a conventional manner, under the control of an actuator 20 (preferably consisting of a multi-stage hydraulic cylinder), which engages a corresponding attachment member 21 provided on the front edge of the tank 18 with the stem of the piston thereof. Preferably, the tank 1 8 further has, in a conventional manner, the rear wall thereof oscillating about the upper horizontal side or shaped as a single or double door and articulated to one or both the vertical sides thereof.

Preferably, the overall length of the tank 18, measured at the upper edge thereof, is advantageously equal to the length of a thirty-foot ISO container 22, which may thus be placed on the edge of the tank itself and may be locked with respect thereto by means of twist locks 10 placed on said edge, near the rear and front transverse sides thereof, and engaging the corner blocks 12 provided at the corners of said thirty-foot container 22 (see Figure 5). Advantageously, the length of the container mounted on the edge of the tank 18 may also be greater than the length of the tank; however, it is preferred that the rear edge of the container is flush with the corresponding rear edge of the tank.

Advantageously, these twist locks 10 are applied to boxes 26, 26', provided in the suitable positions on the edge of the sides of the tank 1 8, and open outwards and are, therefore, actuatable from the outside. In particular, the twist locks 10 are located in such positions to engage the corner blocks 12 both of a thirty-foot ISO container 22 and of a rear twenty-foot ISO container 24 and a front twenty-foot ISO container 24, the latter, in addition, being partially tied to corresponding twist locks 10 of the tank 18 and partially to the twist locks 10 of the front cross-member 6' of the chassis 2 (see Figure 10). To this end, the edge of the tank 18 conveniently lies on the same plane as the upper surface of the cross-member 6' and as the front section of the struts 4.

Conveniently, the width of the tank 18 is slightly greater than the standardized width of conventional containers intended to rest/be mounted on the edge of said tank.

Advantageously, the twist locks 10 are mounted on the edge of the tank 18 so as not to protrude externally/laterally with respect to the overall size of the tank itself.

Advantageously, the twist locks 1 0, which in certain loading conditions shall not be used, are of the conventional retractable type, since the intermediate twist locks not engaged in the corner blocks of the loaded container shall not emerge from the upper edge of the tank 18 to avoid being an obstacle.

Furthermore, in order to ensure a substantial non-deformability of the edges of the tank 18, both when it contains bulk goods and when it is loaded with a container, the two sides of the tank are advantageously connected to each other by means of at least one substantially inextensible tie-rod 28, which may be advantageously engaged with the ends thereof in two corresponding twist locks 10, applied to the two boxes 26, placed on the two longitudinal sides of the tank 18 (see Figures 2 and 3).

To further ensure the tying of the thirty-foot container 22 or of the forty- foot container 14 to the tank 18 also along the sides thereof, or also of a twenty- foot container 24 loaded in the front part of the chassis 2, the invention includes the use of clamps 30 which simultaneously engage the upper plate of each box 26 or 26' and the overlying lower edge projecting outside the container placed on the edge of the tank (see Figure 8). Advantageously, conventional retractable legs 34 are also applied to the chassis 2, on which the semi-trailer rests when released from the tractor in parking places.

The semi-trailer in accordance with the invention operates as follows: when the transport of bulk goods is requested, these are loaded into the tank 18 to be transferred to the desired place of destination, after the semi-trailer has been hooked to a tractor in a conventional manner. At this stage, the semitrailer operates in the conventional manner as any other lowered semi-trailer provided with a tank.

In addition, unlike a conventional semi-trailer, the semi-trailer in accordance with the invention is configured so as to receive a forty-foot container 14 or a thirty-foot container 22 or one or two twenty-foot containers 24 over the tank 18.

In the case of a forty-foot container 14 (see Figure 9), this is tied to the upper edge of the tank 18 with the two rear corner blocks 12 thereof as well as with the clamps 30 which simultaneously clamp the upper plate of the boxed elements 26, 26' integral with the tank 18 and the lower lateral edges 32 of the container 14 (see Figure 8).

During transport, it is convenient for the container 14 to be also tied with the two front corner blocks to the two twist locks 10 applied to the cross-member 6' of the chassis 2, while during the step of tilting the tank 18 with the container 14 tied thereto, clearly, the two front corner blocks 12 must be previously released from the two twist locks 10 of the cross-member 6.

In the case of a thirty-foot container 22 (see Figure 5), everything occurs as in the case described above of a forty-foot container 14, excluding the tying of the front corner blocks 12, which in this case do not affect the twist locks 10 provided at the end of the cross-member 6', but the twist locks 10 applied near the front transverse edge of the tank 18.

In the case of two twenty-foot containers 24 (see Figure 10), these may be tied to the tank 18 so that the rear one is fastened to the twist locks 10 applied near the rear transverse edge of the tank 18 and to the twist locks further back applied to the two intermediate boxes 26, and the front one is fastened to the twist locks 10 further ahead applied to the same two intermediate boxes 26, and is also held by clamps 30 applied, with the methods already seen, to the front boxes 26' and is fastened to the twist locks 10 applied to the front cross-member 6', similarly to a forty-foot container 14.

In the case of a single twenty-foot container 24 , this is tied to the rear part of the semi-trailer (see Figure 1 1 ) and, since it forms an unbalanced load which may insufficiently weight on the fifth-wheel coupling of the tractor, with difficulties in controlling the vehicle on the road, the invention conveniently provides that, near the front end of the chassis 2, a ballast may be applied, which, for example, may consist of one or more receptacles 36 preferably made of plastic, which may be filled, for example, with water to an extent suitable for the correct distribution of the load.

Since, in addition, this embodiment may entail that, once fulfilled the function thereof, the receptacle 36 shall be left in the place of destination, with difficulty in recovering it for a subsequent use, the invention also provides that, in addition to the receptacle 36, one or more further receptacles 36' (see Figure 13) may be mounted on the chassis 2. These are positioned on the chassis below the tank 18 and are connected to the receptacle or to the receptacles 36 by means of one or more ducts for the transfer, when necessary, of ballast water, by means of any pumping system, which, in addition, may be replaced by gravity when transferring water from the receptacles 36 to the receptacles 36'.

From what has been said, it is clear that the semi-trailer in accordance with the invention is particularly advantageous with respect to conventional semi-trailers, since it combines the features of a conventional low bed with a tank for the transport of bulk goods with the further advantageous feature of allowing the transport of one or more containers. This, in turn, allows to make more rational and organized use of all the routes of the semi-trailer, significantly reducing the costs of the routes themselves.

Furthermore, by virtue of the novel application of twist locks on the edge of a tilting tank, the semi-trailer in accordance with the invention allows the same tank to operate as a support and anchoring plane for a container and the equipment provided for the tilting thereof to operate as equipment for the tilting of the container.