The present invention relates to an anti-siphoning device, particularly for preventing the extraction of fuel from tanks.

Nowadays it is known to provide tanks for motor vehicles which are substantially constituted by very capacious containers into which the insertion of the fuel is done by way of an adapted inlet.

Such tanks are usually arranged below the loading surface of the vehicle, at preset heights both from the ground and from the chassis, in a sheltered area, usually in the space between the axles of two wheels.

Conventional tanks suffer a number of problems. First of all their great capacity has entailed the provision of nozzles for pumps for dispensing fuel which have a high flow-rate, since they necessarily have to dispense as much as hundreds of liters per minute in order to fill such tanks.

Such nozzles have standardized dimensions for the dispensing duct, which must be placed with the end tip in abutment in the inlet, and must then dispense the fuel at high speed; this entails the necessity that the dispensing duct must be positioned correctly in the inlet, usually at right angles to it in order to prevent one or more drawbacks from occurring, which include: splashing and backing-up owing to cross-sections which are of insufficient capacity for the flow-rate of the dispensing nozzle, or arrest of the flow of fuel from the nozzle owing to the automatic shut-off thereof.

Such method of positioning creates problems when the distance between the loading surface of the vehicle/trailer and the inlet is lower than the overall height that the nozzle has to assume in the condition in which the dispensing duct is correctly positioned in the inlet.

This entails the necessity to position the nozzle incorrectly, with consequent non-optimal positioning in axial alignment of the dispensing duct in the inlet and consequent non-optimal dispensing of the fuel, given that it does not flow axially to the inlet, and with an increase in the total time required to carry out the complete delivery.

Furthermore, in conventional tanks there is the problem of preventing the drawing-off for example of Diesel fuel; thus solutions of the mechanical type are known, in which it is sought substantially to reduce to the minimum the cross-section of entry to the tank in order to obstruct the introduction into it of flexible tubes for extracting the fuel.

In such conventional solutions it is sought to prevent access to the tank by using a tube, which is arranged between the entry point of the refueling inlet and the inside of the tank proper, and which contains a perforated metallic net or a '"cobweb" of baffles, which are arranged on multiple levels and mutually offset.

These solutions, which therefore consist substantially of using a mechanical obstruction, although they provide a sufficient level of barring, also make it difficult to get liquid into the tank, for example Diesel fuel, when refueling, given that the Diesel fuel is forced to be deviated and turned back in several directions, in a chaotic manner and not in the direction of flow, thus forcing the person carrying out the refueling to choke the flow of fuel, increasing the time necessary to conclude the filling of the tank, so as to avert the sudden release of the nozzle by the intervention of the safety valve of the nozzle, and the interruption of the flow.

Furthermore if the barrier system against extracting Diesel fuel is arranged on the bottom of the tube of the anti-siphoning device fitted on the tank, such tube will be submerged completely once the tank has been filled with fuel.

In this case, once the cap of the tank is unscrewed it is possible to easily extract the Diesel fuel comprised between the surface of the liquid and the bottom of the tube.

Considering that some tanks have a very large footprint in plan view, which generates capacities of as much as 1000 liters, it is easy to see that a few centimeters of Diesel fuel multiplied by the horizontal surface of the fuel contained in the tank translates to in many dozens of liters of fuel that can be easily removed.

A further problem is constituted by the necessity to connect the anti- siphoning device fitted with the obstruction to the mouth of the tank; the conventional coupling systems involve either the use of metallic elements to be deformed, such as for example metallic tongues, or perforation and riveting of an anti-theft ring onto the tank body.

All such conventional systems require operations of greater or lesser length and special equipment, and they still allow ill-intended individuals, properly equipped, to remove the device.

The principal aim of the present invention is therefore to resolve the above mentioned technical problems, while eliminating the drawbacks in the cited known art, by providing a device for tanks which makes it possible to prevent the theft of fuel from the tanks and at the same time to achieve an optimal and rapid dispensing of fuel and which at the same time defends the fuel contained in the tank from the sights of ill-intended individuals provided with means adapted to siphon off the contents of the tank.

Within this aim, an object of the invention is to also prevent the drawing-off of fuel from the tank in the condition where the tank is full.

A further object of the invention is to provide a device that makes it possible to prevent the theft of fuel while at the same time enabling an optimal and rapid dispensing of fuel when inserting the nozzle of the pump of the filling station.

Another object is to provide a device that is structurally simple and is low cost.

This aim and these and other objects which will become better apparent hereinafter, are achieved by an anti-siphoning device, particularly for preventing the extraction of fuel from tanks, which comprises a second ring which is provided with an axial tube and with which a third ring is associable which can be coupled to said tank, characterized in that the first end of a duct which protrudes within said tank is associated rotatably with said axial tube and is provided, axially and at the second end, with an ogive which is adapted to guide and direct the flow of the fuel according to a fluid stream, means being provided for spacing apart said ogive from the inner lateral surface of said duct.

Further characteristics and advantages of the invention will become better apparent from the detailed description of a particular, but not exclusive, embodiment, which is illustrated by way of non-limiting example in the accompanying drawings wherein:

Figure 1 is a perspective side view of the device according to the invention;

Figure 2 is a view from above of the device with the ogive in axial alignment with the duct;

Figure 3 is a sectional view of the device taken along the line III-III in Figure 2;

Figure 4 is a sectional view of the device taken along the line IV-IV in Figure 2;

Figure 5 is a view from above of the device with the duct rotated with respect to the assembly of rings;

Figures 6 and 7 are sectional views of the device respectively taken along the lines VI- VI and VII- VII in Figure 5;

Figure 8 is an exploded view of the device;

Figures 9 and 10 show the device with the nozzle inserted in two different configurations for the tank;

Figure 11 shows the spring in an extended condition.

In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be interchanged with other, different characteristics, existing in other embodiments.

With reference to the figures, the reference numeral 1 generally designates a anti- siphoning device, particularly for preventing the extraction of fuel from tanks 2 of vehicles of the type with a vertical or oblique connector.

Usually the tanks 2 are positioned below the loading surface 3 of the vehicle at a preset distance H from the device 1 which is further positioned inward with respect to the overlying loading surface 3, for its better protection.

The device 1 comprises a first ring 4, which is usually used as an interconnection element with a cap. In the specific embodiment shown, this is annular and is perforated axially; it is associated, or rendered integral so as to constitute a single element, with an underlying second ring 5, which is substantially T-shaped, perforated axially and provided with a first head 6 from the perimetric rim of which a wall 7 and an axial tube 8 protrude, on the opposite side with respect to the first ring 4.

The first ring 4 may be substituted by a cap or by a valve or by any other means adapted to close the entry port of the device 1.

A T-shaped third ring 9 is associated with the second ring 5 and comprises thus a second head 10 which can be associated, for example by screwing or by fixing in a bayonet-like manner, internally with the wall 7, and a stem 11 which is provided externally with means for fixing to the inlet of a tank, such as for example a threading or a bayonet, and which is arranged concentrically and externally to the axial tube 8.

The stem 11 can be externally shaped according to the desired type of tank inlet for which it will be designed.

The third ring 9 is kept associated with the second ring 5 by way of a retaining ring or "C-clip" 12 in elastic steel.

The set of the first ring 4, second ring 5 and third ring 9 can thus be coupled to the tank 2.

Concentrically to and inside the axial tube 8, the first end 13 of a duct 14, which protrudes with its second end 15 within the tank 2, can be arranged and associated rotatably. The duct 14 is substantially cylindrical and a plurality of axial slots 16, which are adapted to allow the venting of the air from the tank 2, are provided at the outer lateral surface of the first end 13.

At the first end 13 of the duct 14 there is, along the same transverse axis, a pair of first holes 17a, 17b.

At the end tip of the axial tube 8 there is, along the same transverse axis, a pair of second holes 18a, 18b.

Once the duct 14 has been positioned with respect to the axial tube 8, the pair of first and second holes 7a, 17b, 18a, 18b are mutually axially aligned so as to allow the placement of a pair of pivots 19a, 19b which allow the rotatable connection of the duct 14 to the axial tube 8.

The duct 14 can thus oscillate with respect to the axial tube 8, as illustrated in Figure 6, by a desired angle.

Inside the duct 14 there is, between the first and second ends 13, 15, a step 20 which constitutes an abutment for the end of the dispensing duct 21 of a nozzle 22 once it is arranged inside the device 1.

In particular, the maximum angle of inclination entails the possibility, once the dispensing duct 21 of the nozzle 22 has been inserted in the device 1, that the dispensing duct 21 be arranged in abutment on the step 20, the duct 14 and the dispensing duct 21 remaining substantially mutually axially aligned.

An ogive 23 is associated inside the second end 15 of the duct 14 and is adapted to guide and direct the flow of the fuel according to a fluid stream.

To this end the cross-section of the inner lateral surface of the second end 15 of the duct 14 is slightly curved.

The ogive 23 is provided in a downward region with means which are adapted to space the ogive 23 apart from the inner lateral surface 24 of the duct 14 and which are adapted to prevent the insertion of tubes to draw fuel; the means are constituted by a flat spring 25 which is folded in a zigzag arrangement and is then wound at an annular slot 26 which is provided in a downward region with respect to the ogive 23 and abuts against the inner lateral surface 24.

Advantageously, in order to allow the maintenance of the spring 25 if desired, the second end 15 of the duct 14 is detachably associable with a dome 27 for supporting and containing the spring 25.

Finally, a gasket 28 can be associated coaxially with the stem 11 of the third ring 9.

Use of the invention is thus the following: when the dispensing duct 21 of the nozzle 22 is inserted in the device 1, a condition of axial alignment can be maintained between the dispensing duct 21 and the duct 14 with the latter arranged in abutment on the step 20, and this in order to enable an optimal dispensing of the fuel.

Thanks to the inclination that the duct 14 can assume with respect to the first ring 4, second ring 5 and third ring 9, such optimal positioning is achieved even if the height H between the loading surface 3 and the device 1 is lower than the height of the nozzle 22 once inserted in the device 1.

Thus it has been found that the invention fully achieves the intended aim and objects, a device being provided which makes it possible both to achieve an optimal and rapid dispensing of fuel and at the same time to prevent the drawing-off of fuel from the tank even in the condition where the tank is full.

The invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Obviously, the materials used as well as the dimensions of the individual components of the invention may be more pertinent according to specific requirements.

The various means of achieving certain different functions certainly need not coexist only in the embodiment shown, but may be present in many embodiments, even if they are not shown. The characteristics indicated above as advantageous, convenient or the like, may also be missing or be substituted by equivalent characteristics.

The disclosures in Italian Patent Application No. TV2014A000097 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.