Pipe joints or couplings – For plural component line
Reexamination Certificate
1999-12-30
2002-06-25
Nicholson, Eric K. (Department: 3627)
Pipe joints or couplings
For plural component line
C285S238000, C138S125000, C138S109000
Reexamination Certificate
active
06409225
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hose-connector assembly used for fuel transportation or other purposes in automotive vehicles, which assembly includes a hose with an outer protector tube and a connector. This invention is also concerned with a method of producing such a hose-connector assembly.
2. Discussion of the Related Art
A hose made of a rubber material has been conventionally used as a fuel transporting hose for automotive vehicles. Recently, however, there is a growing tendency of using a resin tube such as a tube made of nylon or other hard resin material, which has high gasoline impermeability and which is less expensive than a rubber hose. This tendency of using a resin tube in place of a rubber hose applies to an air hose and hoses having other applications in automotive vehicles.
The hose using a resin tube is required to be protected against an external mechanical impact or heat, by an outer rubber protector tube or layer which covers the inner resin tube. For instance, the outer rubber protector tube is made of ethylene propylene rubber or other EP rubber material which has high degrees of weather and heat resistances. In particular, the outer rubber protector tube is essential for the fuel transporting hose, in order to reduce the heat transfer to the fuel within the resin tube, upon generation of a flame for some reason or other.
For installing the fuel transporting hose, for example, on an automotive vehicle, a tubular connector is partly press-fitted into one or both of the opposite end portions of the hose, so that a pipe or other member is connected to each connector. Typically, a tubular connector of a so-called “single-action engagement” type is generally used, for permitting easy, quick connection of the pipe or other member to the hose, with a single action of pushing the pipe into the end portion of the hose.
An example of the recently developed, widely used hose-connector assembly for fuel transportation or other purposes used for automotive vehicles is illustrated in FIG.
4
. This hose-connector assembly includes an inner resin tube
1
, an outer rubber protector tube
2
which covers the outer surface of the inner resin tube, and a tubular connector
3
which is inserted at one end thereof into each of the opposite end portions of the resin tube
1
so that a suitable member is connectable to the connector
3
at the other end.
The known hose-connector assembly shown in
FIG. 4
is produced by preparing the resin tube
1
and the rubber protector tube
2
separately from each other, and press-fitting the rubber protector tube
2
onto the outer circumferential surface of the inner resin tube
1
. This manner of assembling the resin tube
1
and the rubber protector tube
2
into the hose inevitably causes the opposite end portions of the inner resin tube
1
to extend from the opposite ends of the rubber protector tube
2
. This tendency is remarkable particularly where the resin tube
1
is a bent tube. In this case, a relatively large clearance or gap is likely to be present between each end portion of the rubber protector tube
2
and the outer surface of the inner resin tube
1
.
Thus, each end portion la of the resin tube
1
of the known hose-connector assembly is exposed, and is not covered and protected by the outer rubber protector tube
2
. The exposed end portion
1
a
is relatively likely to be overheated and damaged in a short time upon generation of a flame near the exposed end portion
1
a
, for instance. Accordingly, the rubber protector tube
2
cannot serve its assigned function of protecting the resin tube
1
against heat or flame from which the fuel flowing in the resin tube
1
must be isolated.
Another problem with the known hose-connector assembly is that it is difficult to securely attach the tubular connector
3
at its nipple portion
3
a
to the corresponding end portion of the hose
1
,
2
, since the end portion
1
a
of the resin tube
1
is exposed and is not covered by the corresponding end portion of the rubber protector tube
2
. Namely, the hose cannot be held with a suitable clamping tool being fitted on the outer surface of the end portion of the rubber protector tube
2
when the nipple portion
3
a
is press-fitted into the exposed end portion
1
a
of the resin tube
1
, so that the exposed end portion
1
a
of the resin tube
1
tends to be easily buckled upon press-fitting of the nipple portion
3
a
into the exposed end portion
1
a
, which is not externally supported by the outer rubber protector tube
2
.
A static electricity may be generated due to a friction between the fuel and the resin tube
1
in which the fuel flows. To avoid the generation of a spark due to the static electricity, it is required that the static electricity be discharged from the resin tube
1
through a pipe (usually a metallic male member) to which the tubular connector
3
in the form of a male member is connected.
To meet the above requirement, the tubular connector
3
is required to be made of a metallic material or an electrically conductive resin material, while the resin tube
1
to which the connector
3
is connected is required to be electrically conductive. On the other hand, however, the resin tube
1
is required to have a high degree of gasoline impermeability, and is therefore difficult to be made solely of an electrically conductive resin. That is, the resin tube
1
is required to include not only an inner layer of an electrically conductive resin such as electrically conductive ETFE (copolymer of ethylene and tetrafluoroethylene), but also an outer layer made of nylon, for example. This results in an increase in the cost of manufacture of the fuel transporting hose.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a relatively inexpensive hose-connector assembly having am inner resin tube and an outer rubber protective tube and a tubular connector, which assembly has sufficiently high degrees of weather and heat resistances and which are less likely to be buckled upon press-fitting of the connector to the resin tube.
An optional object of the invention is to provide a hose-connector assembly which permits static electricity to be discharged from the resin tube through the connector.
A second object of this invention is to provide a method suitable for producing such a hose-connector assembly.
The first object may be achieved according to a first aspect of this invention, which provides a hose-connector assembly comprising an inner resin tube having an outer circumferential surface and opposite end portions, an outer rubber protector tube which covers an outer circumferential surface of the inner resin tube over an entire length of the inner resin tube, and a tubular connector having opposite end portions one of which is press-fitted in each of at least one of opposite end portions of the inner resin tube.
In the hose-connector assembly of the present invention constructed as described above, the outer circumferential surface of the inner resin tube is covered and protected by the outer rubber protector tube, over the entire length of the inner resin tube, so that the hose exhibits increased degrees of heat and weather resistances even at the opposite end portions of the inner resin tube. In particular, the end portions of the inner resin tube covered by the outer rubber protector tube are highly protected from a flame possibly generated near the end portions of the resin tube, where the hose-connector assembly is used on an automotive vehicle, for instance.
The present hose-connector assembly wherein the end portions of the inner resin tube are externally protected by the end portions of the outer rubber protector tube has another advantage that the hose can be held by a suitable clamping tool fitted on the outer surface of the end portion of the outer rubber protector tube when the end portion of the tubular connector is press-fitted into the end portion of the inner resin tube. Accordingly, the end portion o
Burr & Brown
Nicholson Eric K.
Tokai Rubber Industries Ltd.
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