Acoustics – Sound-modifying means – Muffler – fluid conducting type
Reexamination Certificate
2002-06-25
2004-04-06
Nappi, Robert (Department: 2837)
Acoustics
Sound-modifying means
Muffler, fluid conducting type
C181S227000, C181S212000
Reexamination Certificate
active
06715581
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to improvements in hot exhaust gas pipes and mufflers and more particularly pertains to new and improved decorative exhaust gas pipes and mufflers used on motorcycles and customized automobiles.
2. Description of Related Art
One of the most critical problems confronting the developers of motorcycle exhaust pipes and mufflers or exhaust pipes and mufflers for automobiles which are exposed for appearance purposes has been the prevention of heat discolorization of the chromed exhaust pipes and muffler casings from the extreme heat generated by high engine performance.
Although the prior art has been concerned with preventing heat transfer to the outer housing of a motorcycle exhaust system, none have really accomplished that goal, none have prevented heat discoloration as the present invention. U.S. Pat. No. 4,356,885 for a Chambered-Core Motorcycle-Exhaust Apparatus was granted on Nov. 2, 1982 to Christy J. Dello. The exhaust system described in the Dello patent is concerned with a double wall exhaust system wherein the inner core is mounted within a tubular housing having a larger diameter than the inner core so as to establish an annular chamber between the outer housing and the inner exhaust core. Dello specifically requires the use of an inner exhaust core system that has a plurality of interconnected pipe segments.
U.S. Pat. No. 3,858,678 was granted Jan. 7, 1975 for a Muffler With Rotary Gas Flow to Ralph Haren. It is directed to a muffler construction that has an outer shell which is clamped to the ends of a flow tube which contains flow obstruction devices to prevent or restrict straight through gas flow.
U.S. Pat. No. 3,104,733 was granted Sep. 24, 1963 for a Sound Attenuating Gas Pipe to Edmund Ludlow. It is directed to an exhaust system which has an outer pipe with a plurality of sections or inserts mounted within the outer pipe that are coaxially aligned within the outer pipe to define a main gas flow passage therethrough. The combination is designed so that each adjacent pair of inserts act in combination with the adjacent wall of the outer pipe to define a “resonating chamber of volume”.
U.S. Pat. No. 5,799,395 was granted Sep. 1, 1998 and U.S. Pat. No. 5,907,134 was granted May 25, 1999 for Air Gap-Insulated Exhaust Pipe And Process For Manufacturing An Air Gap-Insulated Exhaust Pipe to Thomas Nording, et al. Both patents are directed to a double wall exhaust pipe wherein the inner pipe which is comprised of sections connected by a sliding fit which are prevented from contacting the walls of the outer pipe as the result of the thermal expansion of both pipes during operation.
FIG. 9
illustrates a prior art double wall exhaust pipe construction for motorcycles made and sold by Hooker. The internal hot gas bearing pipe
69
connects to the engine by a mounting flange
71
and routes the hot gases to its output end
73
. The internal pipe
69
is mounted in a larger diameter external pipe
67
which has a cut-away section
75
that runs the length and shape of the internal pipe
69
. The output end
73
of the internal pipe
69
slips into a slip joint
77
and is held in place by a plurality of hose clamps
79
,
81
and
83
which are held to the inside of the external pipe
67
by loops
78
,
80
and
82
. Besides not being a very secure mounting, the heat transfer from the internal pipe
69
to the external pipe
67
still presents bluing problems. Various coatings on the internal pipe, such as a ceramic coating have been tried to prevent the bluing problem. The pipes come without a muffler. However, a muffler core can be accommodated at the output end
87
of the external pipe
67
. The manufacturer recommends using either a louvered core or a tuned core. Inserting a louvered into the output end
87
of the external pipe
67
creates a single wall muffler with the hot exhaust gases contacting the internal surface of the external pipe
67
at the output end
87
. This creates bluing of the output end
87
. A tuned core is simply a pipe extension that may vary in diameter from the internal pipe
67
.
Applicant's double wall pipes and muffler have solved the heat discoloration problem which the prior art has been unable to do.
SUMMARY OF THE INVENTION
A decorative chromed exhaust pipe for internal combustion engines is provided which does not discolor from the heat generated by the exhaust gases flowing from the engine through the pipes and to and through the muffler. A double-walled muffler is completely encased by an interior casing which only allows gases to flow out the back end of the housing. The exhaust pipe, from the mounting flange to the double-walled muffler has a double wall construction with the exterior wall chromed. The exterior chromed pipe is cut-away on its back side, from the mounting flange to the muffler, allowing the interior one piece pipe to be inserted through the cut-away section and be air cooled during movement. Mounting flanges are welded to the exterior and interior pipes at the back for mounting the exhaust pipe to the vehicle and to hold the interior pipe in a spaced apart relation to the exterior pipe. For larger pipes, separate spacers are welded to the exterior and interior pipes to hold the interior pipe in a spaced relation to the exterior pipe. During operation, the cut-away back side of the exterior pipe provides cooling to the exterior pipe sufficient to prevent heat discoloration of the exterior pipe under the heaviest load conditions. The double-walled construction of the muffler with an air layer between the outside wall and the inside wall prevents the muffler from bluing. In the case of dual exhaust pipes, a Y-shaped collector routes the exhaust from both pipes into the double-walled muffler.
REFERENCES:
patent: 3104733 (1963-09-01), Ludlow
patent: 3382948 (1968-05-01), Walker et al.
patent: 3479145 (1969-11-01), Lentz
patent: 3500954 (1970-03-01), Willette
patent: 3677365 (1972-07-01), Wright et al.
patent: 3858678 (1975-01-01), Haren
patent: 4356885 (1982-11-01), Dello
patent: 4419113 (1983-12-01), Smith
patent: 4487289 (1984-12-01), Kicinski et al.
patent: 5036947 (1991-08-01), Metzger
patent: 5388408 (1995-02-01), Lawrence
patent: 5464952 (1995-11-01), Shah et al.
patent: 5508478 (1996-04-01), Barry
patent: 5799395 (1998-09-01), Nording et al.
patent: 5907134 (1999-05-01), Nording et al.
patent: 5966933 (1999-10-01), Ishihara et al.
patent: 6026930 (2000-02-01), Ogisu et al.
patent: 6408980 (2002-06-01), Dooley
patent: 6431311 (2002-08-01), Brown et al.
patent: 2002/0050419 (2002-05-01), Dooley
patent: 2002/0166719 (2002-11-01), Dooley
patent: 199 12 466 (1999-10-01), None
patent: 0 448 728 (1991-10-01), None
patent: 60175720 (1985-09-01), None
Patent Abstracts of Japan, vol. 012, No. 134 (M-689), Apr. 23, 1988—& JP 62 255514 A (Yamaha Motor Co., Ltd.), Nov. 7, 1987 abstract; figures 1-8.
Patent Abstracts of Japan, vol. 1998, No. 05, Apr. 30, 1998—& JP 10-002220 A (Suzuki Motor Corp.), Jan. 6, 1998 abstract; figures 1-3.
Patent Abstracts of Japan, vol. 008, No. 158 (M-311), Jul. 21, 1984—& JP 59 054722 A (Honda Giken Kogyo KK), Mar. 29, 1984 abstract; figures 1-5.
White Brothers American Street Catalog #20, 1998.
Miller Patrick L
Nappi Robert
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