TECHNICAL FIELD OF THE INVENTION

This invention relates to an anti-siphon device for a fuel tank.

BACKGROUND ART

Theft of fuel from motor vehicle tanks is a wide spread issue, that is especially prevalent with large trucks whose fuel tanks can carry hundreds of litres of fuel.

All that is required of a thief is to remove the fuel cap and insert a length of tube into the tank to siphon fuel out of the tank and into another container.

Various devices have been developed in an attempt to prevent the insertion of a siphon tube into a fuel tank, however these devices all have drawbacks. One such device has the side effect of substantially increasing the time required to fill the fuel tank. Another such device is known to cause splash back of fuel when filling the tank of the truck. This causes deactivation of an automatic fuel dispensing system. This means that the automatic fuel dispenser cannot be left to fill the tank, while the truck driver attends to other duties at the filling station, but requires constant monitoring by the truck driver or attendant.

It is an object of this invention to provide an anti-siphoning device for a motor vehicle fuel tank which, at least partially, alleviates some of the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with this invention, there is provided an anti-siphoning device for a motor vehicle fuel tank, the device including a hollow cylindrical insert securable within the fuel tank inlet, and having a solid base, characterised in that at least a section of the wall of the insert comprises a number of vertically oriented rods, the rods being spaced apart from one another and shaped to deflect the fuel out of the insert and into the fuel tank.

The rods are preferably rounded in cross-section, further preferably circular in cross- section.

The rods may extend from the base of the insert towards the top of the insert. The space between the rods is preferably large enough to allow the free flow of fuel through the spaces in the insert and into the fuel tank, but narrow enough to prevent the insertion of a siphon tube there-through and jnto the. fuel tank. ,

The rods preferably terminate in a solid wall towards the top of the insert to form the neck of the insert. The depth of the neck may be dependent on the shape and configuration of the fuel tank in which the insert is to be housed.

The internal surface of the base of the insert is preferably convex, further preferably cone like in shape to aid in the deflection of fuel into the fuel tank.

The insert may additionally include one or more reinforcing rings located along its length, the reinforcing rings having holes therein through which the rods may be inserted. The rings may assist in maintaining the spaces between the rods, and in preventing the bending apart of any of the rods.

The insert may additionally include an adapter to allow the insert to be used in conjunction with an existing fuel tank cap.

The insert may additionally include a sleeve located around the neck, the sleeve including air vents to enable the flow of air out of the fuel tank to remain discrete from the flow of fuel.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below by way of example only and with reference to the following figures, in which:

Figure 1 is a side view of one embodiment of the invention,

Figure 2 is a side view of the same embodiment of the invention including an adapter,

Figure 3 is a side view of an alternative form of the invention,

Figure 4 is a side view of a further alternative embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

Referring to figures 1 to 4 in which like features of the invention are indicated by like numerals, the anti-siphoning device for a motor vehicle fuel tank, includes a cylindrical insert 10 securable within the fuel tank inlet (not shown). The walls 12 of the insert 10 include a number of rods 14 extending from the base 16 to the neck 18 of the insert 10. A circumferential flange 19 is located at the top of the neck 18.

Referring to figures 1 and 2, the insert 10 is of a fairly uniform circumference along its length. Referring to figure 3, and in an alternative embodiment of the invention, the circumference of the neck 18 may be wider than the rest of the insert, in which case an additional ring shaped plate 41 may be provided at the base of the neck to join the neck 18 to the rods 14.

The rods 14 are spaced apart from one another and are circular in cross section. The spaces 20 between the rods 14 are large enough to allow the free flow of fuel through the spaces 20 and into the fuel tank, but narrow enough to prevent the insertion of a siphon tube there-through.

The internal surface 26 of the base 16 of the insert 10 is conical in shape, the cone 26 extending into the interior of the insert 10.

Reinforcing rings 24 are located along the length of the insert 10 to assist in maintaining the spaces between the rods 1 and to prevent the rods 14 from being forced apart. The rods 14 may be inserted through holes located around the circumference of the reinforcing rings 24.

Gaskets 26 may be located on the flange 19 to ensure a sealing fit in the opening of the fuel tank.

Referring to figure 2, an adapter 30, sized to fit the fuel tank inlet, may be attached to the top of the insert to assist in securing the insert in the tank and to ensure that the fuel tank cap 32 still fits the tank once the insert 10 is in place. Alternatively, and referring to figure 3, the neck 18 and opening of the insert may be customised to receive the fuel cap 32.

Referring to figure 4, and in another embodiment of the invention, a sleeve 34 may be welded around the neck 18 of the insert 10. Air vents 36 located in the sleeve 34 allow air to flow out of the fuel tank through the space between the neck 18 and the sleeve 34, while the fuel is pumped into the tank through the neck 18 of the insert 10. This ensures that the flow of air and fuel remain discrete from each other and minimises frothing of the fuel, thus increasing the speed at which the fuel can be pumped into the tank.

In use, the insert 10 is secured inside the fuel inlet. Referring to figure 3, this may be achieved by means of bolts 40 which extend through the base 41 of the neck into a locking plate 42. The bolts/ screws are preferably snap-off screws that cannot be undone. Alternatively, and referring to figure 4, retaining lugs 38, located on the sleeve 34 are employed to prevent the forced removal of the insert from the fuel inlet. Further alternatively, and referring to Figure 2, the bolts may be secured through the adapter 30.

The solid base 16 at the end of the insert 10 and the small gaps 20 between the rods 14, prevent the insertion of a siphon tube into the fuel tank. However, the gaps 20 are sufficient to allow fuel to flow into the fuel tank, and the rounded sides of the rods 14 aid in deflecting the fuel out of the insert and into the tank, and minimise the splash back of fuel towards the opening of the insert. The cone 26 is also shaped to aid in dispersion of the fuel.

Numerous modifications to this embodiment are possible, without departing from the scope of the invention.

The invention therefore provides a novel anti-siphon device for a motor vehicle fuel tank.