Patent US3586123A successfully refreshed from Google Patents.
US3586123A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Muffler with sequential expansion chambers
Assignee: Paccar Inc
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Filing: 1970-03-16
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Granted: 1971-06-22
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Expires: 1990-03-16
Abstract
Abstract A muffler able to greatly reduce the exhaust sound of powerful truck engines without too greatly increasing the back pressure. The large shell is concentric with first, second and third inner pipes that are axially aligned, and are spaced apart by a distance approximately equal to their diameter. The central inner pipe is much longer than the other two and, within the shell, all are perforated. Each one is supported by two annular bafflesupport members. The central innner pipe has its baffles spaced in about one-third of the distance from each end. The axially inner members of each of the two end pairs of baffles are spaced different distances from the axially inner end of their respective inner pipes, that of the third inner pipe being much closer to the end of the shell than the corresponding baffle for the first inner pipe. As a result, the distance between the axially inner baffle of the first pair is closer to its adjacent baffle of the second pair than is the axially inner baffle of the third pair to its adjacent baffle of the second pair. Hence a series of chambers of different sizes are formed. Further reduction of sound is achieved by dividing the inner pipes into radial sectors or by introducing the exhaust gases in a swirl, or by placing a flow restriction at the entrance end to the second pipe.
Inventors
- 👤 Huston R Marlowe
- 👤 Donald L Stephens
- 👤 John B Selvidge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:28
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/003; F01N1/08; F01N1/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
381 words
A muffler for connection between first and second exhaust pipe sections of an engine, including in combination: a tubular shell about twice the diameter of said exhaust pipe sections, first, second, and third inner pipes substantially identical in diameter to said exhaust pipe sections and axially in line with each other, in and concentric with said shell imperforate end portions of said first and third inner pipes projecting beyond the ends of said shell for connection respectively to said first and second exhaust pipe sections, said second inner pipe and the portions of said first and third inner pipes that lie axially within said shell being perforated, said inner pipes being spaced apart from each other successively by first and second gaps, each about as long as the diameter of said inner pipes, and first, second, and third pairs of annular baffle and support members secured to both said shell and, respectively to said first, second, and third pipes to hold them in position in said shell and to provide annular chambers therearound and to divide said chambers from each other, the axially outer members of said first and third pairs closing the space between said shell and said first and third inner pipes at the ends of said shell, the axially inner members of said first and third pairs being spaced away from the axially inner ends of said first and third inner pipes toward said outer members, the inner member of said third pair lying substantially closer to the outer member of said third pair than the inner member of the first pair lies to the outer member of said first pair, said first inner pipe and said third inner pipe being approximately of the same length, while said second inner pipe is approximately twice as long as the portions of said first or third inner pipes that lie axially within said shell, said second pair of baffle and support members each lying at about one-third of the length of said second inner pipe, so that between them they define a chamber around the middle third of said inner pipe, said members of said second pair lying at different distances From said inner members of said first and third pairs, to define end walls of chambers of different length.
Claim 2
Dependent Claim
381 words
A muffler for connection between first and second exhaust pipe sections of an engine, including in combination: a tubular shell about twice the diameter of said exhaust pipe sections, first, second, and third inner pipes substantially identical in diameter to said exhaust pipe sections and axially in line with each other, in and concentric with said shell imperforate end portions of said first and third inner pipes projecting beyond the ends of said shell for connection respectively to said first and second exhaust pipe sections, said second inner pipe and the portions of said first and third inner pipes that lie axially within said shell being perforated, said inner pipes being spaced apart from each other successively by first and second gaps, each about as long as the diameter of said inner pipes, and first, second, and third pairs of annular baffle and support members secured to both said shell and, respectively to said first, second, and third pipes to hold them in position in said shell and to provide annular chambers therearound and to divide said chambers from each other, the axially outer members of said first and third pairs closing the space between said shell and said first and third inner pipes at the ends of said shell, the axially inner members of said first and third pairs being spaced away from the axially inner ends of said first and third inner pipes toward said outer members, the inner member of said third pair lying substantially closer to the outer member of said third pair than the inner member of the first pair lies to the outer member of said first pair, said first inner pipe and said third inner pipe being approximately of the same length, while said second inner pipe is approximately twice as long as the portions of said first or third inner pipes that lie axially within said shell, said second pair of baffle and support members each lying at about one-third of the length of said second inner pipe, so that between them they define a chamber around the middle third of said inner pipe, said members of said second pair lying at different distances From said inner members of said first and third pairs, to define end walls of chambers of different length.
Claim 3
Dependent Claim
22 words
The muffler of claim 1 wherein said inner pipes are each divided into a plurality of sectors by generally radially extending partitions.
Claim 4
Dependent Claim
29 words
The muffler of claim 1 having means for causing the exhaust gases from said first exhaust pipe section to enter into said first inner pipe with a swirling motion.
Claim 5
Dependent Claim
15 words
The muffler of claim 3 wherein said means for causing comprises inclined radially extending vanes.
Claim 6
Dependent Claim
15 words
The muffler of claim 3 wherein said means for causing comprises generally helically twisted vanes.
Claim 7
Dependent Claim
21 words
The muffler of claim 1 wherein the entrance to the second pipe is made smaller by partial obstructions at that point.
Claim 8
Dependent Claim
385 words
A muffler for connection between first and second exhaust pipe sections of an engine, including in combination: a tubular shell about 2.5 times the diameter of said exhaust pipe sections, first, second, and third inner pipes substantially identical in diameter to said exhaust pipe sections and axially in line with each other, in and concentric with said shell, imperforate end portions of said first and third inner pipes projecting beyond the ends of said shell for connection respectively to said first and second exhaust pipe sections, said second inner pipe and the portions of said first and third inner pipes that lie axially within said shell being perforated, said inner pipes being spaced apart from each other successively by first and second gaps, each within 10 percent as long as the diameter of said inner pipes, and first, second, and third pairs of annular baffle and support members secured to both said shell and, respectively to said first, second, and third pipes to hold them in position in said shell and to provide annular chambers therearound and to divide said chambers from each other the axially outer members of said first and third pairs closing the space between said shell and said first and third inner pipes at the ends of said shell, the axially inner members of said first and third pairs being spaced away from the axially inner ends of said first and third inner pipes toward said outer members, the inner member of said third pair lying substantially closer to the outer member of said third pair than the inner member of the first pair lies to the outer member of said first pair, said first inner pipe and said third inner pipe being approximately of the same length, while said second inner pipe is approximately 2.3 times as long as the portions of said first or third inner pipe that lie axially within said shell, said second pair of baffle and support members each lying at about one-third of the length of said second inner pipe, so that between them they define a chamber around the middle third of said inner pipe, said members of said second pair lying at different distances from said inner members of said first and third pairs, to define end walls of chambers of different length.
Claim 9
Dependent Claim
385 words
A muffler for connection between first and second exhaust pipe sections of an engine, including in combination: a tubular shell about 2.5 times the diameter of said exhaust pipe sections, first, second, and third inner pipes substantially identical in diameter to said exhaust pipe sections and axially in line with each other, in and concentric with said shell, imperforate end portions of said first and third inner pipes projecting beyond the ends of said shell for connection respectively to said first and second exhaust pipe sections, said second inner pipe and the portions of said first and third inner pipes that lie axially within said shell being perforated, said inner pipes being spaced apart from each other successively by first and second gaps, each within 10 percent as long as the diameter of said inner pipes, and first, second, and third pairs of annular baffle and support members secured to both said shell and, respectively to said first, second, and third pipes to hold them in position in said shell and to provide annular chambers therearound and to divide said chambers from each other the axially outer members of said first and third pairs closing the space between said shell and said first and third inner pipes at the ends of said shell, the axially inner members of said first and third pairs being spaced away from the axially inner ends of said first and third inner pipes toward said outer members, the inner member of said third pair lying substantially closer to the outer member of said third pair than the inner member of the first pair lies to the outer member of said first pair, said first inner pipe and said third inner pipe being approximately of the same length, while said second inner pipe is approximately 2.3 times as long as the portions of said first or third inner pipe that lie axially within said shell, said second pair of baffle and support members each lying at about one-third of the length of said second inner pipe, so that between them they define a chamber around the middle third of said inner pipe, said members of said second pair lying at different distances from said inner members of said first and third pairs, to define end walls of chambers of different length.
Claim 10
Dependent Claim
22 words
The muffler of claim 7 wherein said inner pipes are each divided into a plurality of sectors by generally radially extending partitions.
Claim 11
Dependent Claim
21 words
The muffler of claim 7 wherein the entrance to the second pipe is made smaller by partial obstruction at that point.
Claim 12
Dependent Claim
20 words
The muffler of claim 7 wherein the partial obstruction comprises an annular member reducing the diameter of the passage therethrough.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |