Pipe joints or couplings – Packed – Flanged pipe
Reexamination Certificate
1999-12-10
2001-10-09
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Packed
Flanged pipe
C285S368000
Reexamination Certificate
active
06299221
ABSTRACT:
This application has priority benefit of French Patent Application No. 9915592, filed on Dec. 10, 1998.
The present invention relates to a system for the butt fastening of two pipes provided with fastening flanges at their mutually confronting ends to be connected.
In the known fastening systems of this type, it is customary for the first pipe, for example the outlet pipe for the gases of a turboengine, to be equipped with a fastening flange comprising a peripherally projecting collar and provided with an annular plane outer face and with a conical inner face converging toward said outer face, at the same time moving radially away from said pipe, so that said collar has a substantially triangular cross section. In this case, there is provision, in a known way, for the fastening flange of the second pipe, for example the nozzle to be mounted on the gas outlet pipe of said turboengine, likewise to comprise a peripherally projecting collar provided with an annular plane outer face, intended to come to bear against said outer face of the first pipes, and with a conical inner face converging toward the latter outer face, at the same time moving radially away from the corresponding pipe, so that the latter collar likewise has a substantially triangular cross section.
In these known fastening systems, there is then provided a single or double clip of V-shaped cross section, which caps said collars and which bears on said conical inner faces of the latter.
Such a system has the disadvantage of being costly and heavy because of said clip. Moreover, if this clip breaks, for example as a result of wear, fatigue or the impact of a bullet, there is nothing to retain the second pipe which becomes detached from the first, and, in the case of the turboengine considered above, thus making this turboengine, which has lost its nozzle, ineffective in propelling the aircraft. The result of this may therefore be that said aircraft crashes, in particular, for example, due to a possible fire arising from the loss of the nozzle.
In order to overcome these disadvantages, it will be conceivable to modify the above-described fastening system completely, especially by modifying the fastening flange of the first pipe. However, this would not make it possible to improve in a simple way the fastening systems for engines, machines, aircraft, etc. which are already equipped with a fastening collar of triangular cross section.
Thus, the object of the present invention is to overcome the disadvantages of cost, mass and vulnerability of the known systems referred to above, whilst at the same time making it possible to preserve the fastening flange of triangular cross section of the first pipe.
To achieve this, according to the invention, the system for the butt fastening of two pipes provided with fastening flanges at their mutually confronting ends, in which system:
the fastening flange of the first of said pipes comprises a first peripherally projecting collar provided with a first annular plane outer face and with a conical inner face converging toward said outer face, at the same time moving radially away from said first pipe; and
the fastening flange of the second of said pipes comprises a second peripherally projecting collar provided with a second annular plane outer face intended for coming to bear against said first outer face of said first pipe, is notable in that:
said second collar comprises at least two peripheral radial protuberances, each provided with at least one first abutment face, each first abutment face being directed toward said second collar and having a general direction which is transverse to said second outer face;
associated with each radial protuberance is a cuneiform wedge comprising, on the one hand, an inclined face intended for coming to bear against said conical inner face of said first collar and, on the other hand, a second abutment face intended for coming to bear against said first abutment face of the corresponding radial protuberance; and
associated with each radial protuberance are clamping means making it possible to press both the inclined face of the corresponding cuneiform wedge against said conical inner face of said first collar and said second abutment face of said wedge against said first abutment face of said radial protuberance.
Thus, it can be seen that the fastening system of the invention comprises at least two individual and independent localized fastening locations making it possible to overcome the abovementioned disadvantages, each of said fastening locations being provided with a fixed jaw consisting of a radial protuberance and a movable jaw consisting of a cuneiform wedge, and each pair of a fixed jaw and a movable jaw holding by clamping a localized portion of the collar of triangular cross section of said first pipe.
Said clamping means may be of the screw
ut type, each screw passing with play through the corresponding radial protuberance and cuneiform wedge. Of course, said clamping means may comprise in a known way selflocking nuts or be provided with selflocking washers. It would be noted that said first abutment faces of the radial protuberances prevent said screws from undergoing shearing stress and avoid the slipping of the cuneiform wedges and therefore errors of orthogonality of the screws, such errors undoubtedly causing dulling or marking of the flanges and wedges.
Preferably, in order to increase even further the rigidity of the fastening obtained by means of such a pair of jaws, there is provision:
for each peripheral radial protuberance to be provided, furthermore, with a third abutment face at least approximately parallel to said second outer face of said second collar;
for each cuneiform wedge to be provided, furthermore, with a fourth abutment face at least approximately orthogonal to said second abutment face; and
for said clamping means to press both:
the inclined face of the cuneiform wedge against the conical inner face of said first collar,
the second abutment face of the cuneiform wedge against said first abutment face of said protuberance, and
the fourth abutment face of the cuneiform wedge against said third abutment face of said protuberance.
The cuneiform wedges may be individual and unconnected to one another. On the contrary, they may be integral with one another and, if appropriate, each be formed by a portion of a ring machined to the profile of said wedges.
Advantageously, said second collar of the second pipe comprises a plurality of peripheral radial protuberances.
Preferably, means are provided for the peripheral centering of said protuberances of said second collar relative to said first collar of the fastening flange of said first pipe.
Furthermore, means may be provided for centering said fastening flanges relative to one another.
REFERENCES:
patent: Re. 23137 (1949-07-01), Hobbs
patent: 1631654 (1927-06-01), Stoffel
patent: 1652064 (1927-12-01), Sweney
patent: 2653834 (1953-09-01), Purkhiser
patent: 2714020 (1955-07-01), Yates
patent: 2768847 (1956-10-01), Peyrin et al.
patent: 3211477 (1965-10-01), McCoy
patent: 3214203 (1965-10-01), Mongodin
patent: 3301576 (1967-01-01), Vigneron
patent: 3468561 (1969-09-01), Balitsky et al.
patent: 3627357 (1971-12-01), Sanders
patent: 3752509 (1973-08-01), Stafford
patent: 3910610 (1975-10-01), Turner et al.
patent: 4330143 (1982-05-01), Reneau
patent: 6099198 (2000-08-01), Kotzur et al.
patent: 2042164 (1971-01-01), None
patent: 2073836 (1981-10-01), None
patent: 2202022 (1988-09-01), None
Bucci Robert
Chaniot Daniel
Lenhardt François
Bochna David E.
Browne Lynne H.
Eurocopter
Fisher Christen & Sabol
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