Pipes and tubular conduits – Combined – With end structure
Reexamination Certificate
2003-02-13
2004-03-30
Brinson, Patrick (Department: 3752)
Pipes and tubular conduits
Combined
With end structure
C138S155000, C285S374000, C285S231000
Reexamination Certificate
active
06712098
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for connecting a fuel hose. More specifically, the present invention relates to a fuel hose connection method that involves using a ring-shaped sealing member, a hard, pipe-shaped opposing member, and a fuel hose. The opposing member can be a pipe made of metal or resin. The fuel hose has an opposing member insertion section for ensuring a fluid-tight connection between the opposing member and the fuel hose. The present invention also relates to a fuel hose connection structure based on the fuel hose connection method.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,664,608 (EP 0591831 A2) discloses a conventional, multi-layer hose with an outer layer made of rubber. Except for a pipe insertion section, the inner perimeter surface of the hose has a thin inner layer made of a hard metal or resin material having low fuel permeability. The publication states that fuel seepage to the outside is adequately prevented since the section of the inner perimeter surface of the hose that contacts the fuel has an inner layer having low fuel permeability. The publication also states that the hard inner layer is not formed at the pipe insertion section of the hose. Therefore, the required force to insert the pipe is reduced, and there is a high degree of sealing at the pipe connection section. However, since a fixed amount of fuel seeps into the contact section between the inner layer and the pipe, this conventional hose does not provide low fuel permeability, which is required due to stricter regulations on fuel permeability and the like.
Japanese Laid-Open Patent Publication Number Hei 8-294979 shown in
FIG. 1
discloses a fuel hose having a rubber protector
1
covering a fluorocarbon resin tube
2
. A sealing rubber
3
having low fuel permeability is adhered by vulcanization to the inner perimeter surface of the pipe insertion section of the fluorocarbon resin tube
2
. The publication states that the presence of the sealing rubber
3
in the fuel hose reduces the insertion force to insert the pipe and maintains good fuel sealing properties. The publication also states that lower fuel permeability can be achieved by extending the fluorocarbon resin tube
2
to the end of the fuel hose. However, since the pipe is inserted into the hard fluorocarbon resin tube
2
having the sealing rubber
3
on the inner perimeter surface, the pipe is difficult to insert since the required insertion force is very high. Also, the sealing rubber
3
is made of a rubber material having low fuel permeability which is expensive, thereby increasing the cost of the fuel hose. Furthermore, the vulcanized adhesion process used for preventing misalignment of the sealing rubber
3
when the pipe is inserted also increases the cost of the fuel hose.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention provides a fuel hose having low fuel permeability when connecting to pipes and superior fuel sealing properties. The fuel hose of the present invention also reduces the insertion force required to insert the pipe and does not require special increases in cost. Additionally, the present invention provides a method and an apparatus for connecting the fuel hose. Furthermore, the present invention effectively handles the unavoidable degradation in fuel permeability and sealing properties due to aging of the material in the fuel hose connection structure.
A fuel hose of the present invention includes a hose tube and a straight opposing member insertion section. The hose tube is made of a rubber or elastomer, and the opposing member insertion section is located at an end of the hose tube. A sealing ring is inserted into and fits inside a ring-shaped groove located on a section of the inner perimeter surface of the opposing member insertion section which is located toward a center side of the fuel hose along the hose axis (i.e., away from the end of the fuel hose). A ring-shaped tongue piece having a sloped surface hangs over the ring-shaped groove. The tongue piece is located inward in the radial direction from a side wall of the ring-shaped groove that is located toward an end side of the fuel hose along the hose axis (i.e., toward the end of the fuel hose). A thin resin layer having low fuel permeability covers the inner perimeter surface of the ring-shaped groove, including the tongue piece, and the entire inner perimeter surface of the hose tube from the ring-shaped groove toward the center side of the fuel hose along the hose axis (i.e., away from the end of the fuel hose).
“Ring-shaped” refers to a continuous shape extending over the entire perimeter of the hose tube or the hard, tube-shaped opposing member. “A tongue piece having a sloped surface and hanging over the ring-shaped groove” indicates a tongue piece, which has a sloped surface, with lip-shaped cross-section that increases gradually in size over the space of the ring-shaped groove as it extends toward the center side of the fuel hose along the hose axis (i.e. toward the end of the fuel hose).
The present invention provides the following advantages with regard to fuel sealing properties, low fuel permeability, and insertion force on the opposing member.
The sealing member typically provides the fuel sealing properties in fuel hose connection structures, but the sealing member requires a sufficient securing force to prevent misalignment when the hose is connected. As described above, Japanese Laid-Open Patent Publication Number Hei 8-294979 discloses a fuel hose in which the sealing rubber is adhered by vulcanization to the low fuel permeability resin layer to prevent the misalignment of the sealing rubber when the hose is connected. However, vulcanization increases the cost of the fuel hose.
The sealing ring of the present invention is tightly inserted into the ring-shaped groove to ensure a high securing force on the sealing ring and to prevent misalignment of the sealing ring. Thus, the sealing ring of the present invention has a very high securing force without requiring a special process such as vulcanization.
Furthermore, after the hard, tube-shaped opposing member is connected, the engagement projection of the opposing member of the present invention is tightly secured to the ring-shaped groove of the hose tube via the low fuel permeability resin layer and the sealing ring. As a result, the fuel sealing properties are especially good when the pipe is connected.
A thin, low fuel permeability resin layer of the present invention covers the inner perimeter surface of the ring-shaped groove and the entire inner perimeter surface of the hose tube from the ring-shaped groove toward the center side of the fuel hose along the hose axis (i.e., away from the end of the fuel hose). The thin, low fuel permeability resin layer covers not only the inner perimeter surface of the hose tube which contacts the fuel, but also the inner perimeter surface of the ring-shaped groove to which the opposing member is inserted. As a result, there is no risk of fuel leakage at the connecting section of the fuel hose between the low fuel permeability resin layer and the opposing member. Thus, the connecting section has low fuel permeability.
The hard, tube-shaped opposing member is inserted into the straight opposing member insertion section of the fuel hose according to the present invention. The presence of the hard, low fuel permeability resin layer increases the insertion force required to insert the opposing member. However, the resin layer is only formed at the ring-shaped groove, and most of the hose tube is formed from soft rubber or elastomer. As a result, the insertion force on the opposing member can be remain low.
According to another embodiment of the present invention, a fuel hose can include a rubber or elastomer hose tube and a straight opposing member insertion section formed at the end of the hose tube. A ring-shaped groove for inserting and fitting a sealing ring is located on the inner perimeter surface of the opposing member insertion section toward a center side of the fuel
Hioki Koji
Miyajima Atsuo
Sakazaki Kazushige
Brinson Patrick
Darby & Darby
Tokai Rubber Industries Ltd.
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