Filler assembly of an automotive fuel tank

The diameter of a filler cap closing a filler tube is smaller than that of an opening of a filler cover secured to a rear side panel of a vehicle body, through which the filler tube extends outwardly. The filler cover is fastened to a filler neck flange fitted on the filler tube by means of headed screws which pass through spreadable slots formed in the filler cover and are fixed to the filler neck flange.

This invention relates generally to an automotive fuel tank and 
particularly to an improvement to a filler assembly mounted to a body of a 
vehicle for replenishing the tank with fuel. 
In many vehicles, inlets of filler tubes of fuel tanks are open to the 
outside through body rear side panels for fuel delivery into the fuel 
tank. Conventional filler assemblies are associated with shortcomings that 
filler caps are liable to be disengaged from the inlets of the filler 
tubes, when the rear side panel is highly deformed outboard as may occur 
in a rear-end collision of the vehicle. 
It may therefore be a primary object of this invention to provide an 
improved filler assembly of fuel tank in which fitting of filler caps 
within filler tubes is not influenced by external force tending to deform 
the rear side panel outwardly, obviating a dangerous fuel outflow during 
the rear-end collision or the like. Another object of this invention is to 
provide a simple and economical filler assembly construction which 
achieves the above mentioned objects.

As shown in FIG. 1, a conventional filler assembly of a fuel tank 10 
comprises a filler hose 12, preferably flexible, extending from the fuel 
tank 10 and a filler tube 13 having one end fitted within the filler hose 
12, the tube and the hose being clamped together by a hose clamp 14. A 
filler neck 15 with a radial outward flange 15a is then fitted on the 
other end or inlet of the filler tube 13. There is provided a filler cover 
20 secured to the inside surface of the body rear side panel 17 at a 
suitable space for facilitating fuel replenishing service. The filler 
cover 20 defines by its inward flange 20a an opening 19 through which the 
other end of the filler tube 13 together with the filler neck 15 extends 
outwardly of the filler cover. The flange 15a of the filler neck and the 
flange 20a of the filler cover are fastened together by headed screws 21. 
The extended end of the filler tube 13 is closed by a filler cap 18 which 
is to be removed from the tube inlet for re-charge of fuel into the fuel 
tank 10. The diameter of the filler cap 18 is greater than that of the 
opening 19 of the filler cover according to such prior art construction. 
The filler assembly is ordinarily covered by a hingedly movable lid 23 
finished similarly as the rear side panel 17. 
When the vehicle is severely bumped from behind, the rear side panel 17 is 
deformed to protrude outwardly. Consequently, an abnormal force tends to 
separate the filler cover 20 from the flange 15a of the filler neck, 
breaking the screws connecting the two flanges together. The flange 20a 
separated from the filler neck flange 15a then collides with the periphery 
of the filler cap 18, strongly pulling it outwardly. This will cause the 
filler cap 18 to be removed from the tube 13. As a result, fuel flows out 
from the fuel tank, probably causing a vehicle fire. 
Besides, in the aforementioned construction of the filler assembly, a force 
tending to withdraw the filler tube from the filler hose is applied to the 
hose clamp 14. This also results in flowout of fuel from the tank 10. 
A preferred embodiment of the filler assembly according to this invention, 
illustrated in FIGS. 2 and 3, obviates the aforementioned shortcomings of 
the conventional filler assembly. As shown, the diameter of the filler cap 
18' in this embodiment is smaller than that of the opening 19' defined by 
the flange 20a of the filler cover. The flange 15a of the filler neck 
extends upwardly and then outwardly to define an opening (no numeral) 
matching the opening 19'. The two flanges 15a and 20a are releasably 
fastened together by several headed screws 21'. As best seen in FIG. 3, 
each screw is passed through an elongate slot 24 formed in the flange 20a 
and then fixedly screwed into the flange 15a. The width of the slot 24 is 
such that it usually prevents the head of screw from passing therethrough. 
In operation, if the rear side panel is highly deformed outwardly, the 
filler cover 20 tends to be separated from the flange 15a by breaking the 
screws 21'. In this moment, the slots 24 are spread to such a degree 
passing the screw head therethrough so that the filler cover 20 is removed 
from the filler neck flange 15a without breaking the screw 21'. Since the 
diameter of the opening 19' is greater than that of the filler cap 18', 
the filler cover is deformed outwardly without touching the peripheral 
edge of the filler cap 18'. Fuel outflow is prevented even in a severe 
collision of the vehicle from behind, minimizing a damage to the vehicle 
and its occupants resulting from such collision. 
Since, as described, the screw head is passed through the spread slot 24, 
an outwardly acting force influences only the filler cover fixed to the 
rear side panel, whereas the filler neck and therefore the filler tube is 
not subject to such external force. Withdrawal of the filler tube from the 
filler hose is therefore advantageously prevented by this way of 
fastening. 
It will be readily understood from the above description that the preferred 
embodiment of this invention prevents fuel discharge from the fuel tank 
resulting from external force acting on the filler assembly of the tank 
for a rear-end collision or other causes. Moreover, this feature is 
obtained according to this invention by a simple construction of the 
filler assembly without any additional constituent part or element being 
required.