Static Discharge Prevention System for a Largely Non-Metallic Fuel Tank

The present invention relates to vehicle fuel systems and more specifically relates to methods of grounding fuel tanks so as to prevent the buildup of static electricity.

Fuel flowing from a hose or container into an ungrounded fuel tank will cause the formation of a static charge as will the movement of fuel within the tank. The grounding of a metal fuel tank so as to eliminate static charge buildup is an easy task since it merely requires an electrical conductor be connected between some point on the tank and the vehicle frame. However, a different situation is presented when the majority of the fuel tank is made of a non-metallic material such as plastic.

Now there is provided a way of grounding a largely non-metallic fuel tank so as to prevent a static charge buildup.

According to the present invention there is provided a novel, largely non-metallic fuel tank assembly and more specifically there is provided an assembly which is effectively grounded for preventing the formation of a static electrical charge.

An object of the invention is to provide a simple ground assembly in combination with a largely non-metallic fuel tank.

A more specific object of the invention is to provide a ground assembly, for a largely non-metallic fuel tank, which includes a metal ring clamped within the tank filler neck, a metal vent tube connected between the ring and a metal hangar for the tank, and a ground cable coupled to the ring and extending into the tank.

These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the description which follows and from the drawing.

FIG. 1 is a vertical sectional view taken through a mainly non-metallic fuel tank incorporating an electrical ground assembly constructed in accordance with the present invention.

FIG. 2 is a view taken along line 2--2 of FIG. 1 and showing the clip which forms the electrical connection between the vent tube and tank bracket.

Referring now to the drawing, there is shown a grounded fuel tank assembly 10. The tank assembly 10 includes a tank 12 including an elevated tubular filler neck or spout 14. Except for an upper neck portion 16, the tank is formed of a non-metallic material such as plastic. The upper neck portion 16 of the tank 12 is metal and is held within the upper end of the plastic portion of the neck 14 by a hose clamp 18. The metal upper neck portion 16 could be threaded or otherwise adapted for receiving a cap (not shown) of common construction. A vent tube 20 extends along the outside of the tank 12 and has a bent upper end 22 received in a hole provided in the metal neck portion 16. A ground cable 24 extends to the bottom of the inside of the tank and has a connector 26, at its upper end, received on the vent tube end 22. A push nut 28 is received on the tube end 22 and thus holds the cable connector 26 on the end 22 and secures the tube to the filler neck portion 16. A substantially U-shaped, spring metal clip 30 has opposite legs received on the tube 20, with legs having teeth 32 formed on their ends. The clip 30 has a flat surface 34 engaged with a flat surface 36 of the tank 12 and the teeth 32 bear against a metal tank mounting bracket 38 which is connected to a vehicle chassis member 40 by fasteners 42.

In operation, the metal upper portion 16 of the filler neck 14, the vent tube 20, and the tank mounting bracket 34 together with the ground cable 24 cooperate to ground the tank 12 such that static electricity does not build up during the filling of the tank or during the operation of the vehicle carrying the tank.