US3815705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Muffler for a pneumatic percussion tool
Assignee: Thor Power Tool Co
•
Filing: 1972-12-04
•
Granted: 1974-06-11
•
Expires: 1992-12-04
Abstract
Abstract A muffler for attenuating the sounds generated by the operation of a pneumatic percussion tool is disclosed, wherein the muffler is formed in two, symmetrically-shaped halves to facilitate mounting and demounting from the body of the tool. When mounted on the tool, the muffler surrounds a portion of the tool body including the exhaust ports and includes two expansion chambers and elongated passage means arranged in series flow relation. The first and second expansion chambers are arranged on opposite sides of the tool body and are defined in part by the outer surface of the body. A first orifice means having a predetermined area relationship with respect to the area of the exhaust ports, interconnects the first and second expansion chambers. A second orifice means having a predetermined area relationship with respect to the effective flow area of the first orifice means, interconnects the second expansion chamber with the elongated passage means. The exhaust air flow from the tool expands into the first expansion chamber, and undergoes successive expansions as it proceeds through the second expansion chamber and elongated passage means before discharging into the atmosphere. The sound level of the flow is thus attenuated as it expands and changes direction while passing through the muffler. The material of the muffler is an elastomer, which renders it durable and also contributes to its high frequency sound attenuating characteristics.
Inventors
- 👤 D Bennett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:44
CPC Classifications
B; B25; B25D; B25D17/00; B25D17/11; B25D17/12
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
150 words
A muffler for reducing the operating noise level of a pneumatic percussion tool having an elongated body and exhaust port means in said body through which air under pressure discharges when said tool is in operation, said muffler comprising a jacket adapted to surround said tool body in the vicinity of said exhaust port means and having partition means therein adapted to coact with said body to define first and second expansion chambers therebetween, said first expansion chamber receiving air discharging from said exhaust port means, said second expansion cHamber being connected to said first expansion chamber in continuous series flow relation by first orifice means external of said tool body, said jacket having at least one outlet port connecting said second expansion chamber with the atmosphere, and said first and second expansion chambers being arranged on laterally opposite sides of said tool body when said muffler is mounted thereon.
Claim 2
Dependent Claim
150 words
A muffler for reducing the operating noise level of a pneumatic percussion tool having an elongated body and exhaust port means in said body through which air under pressure discharges when said tool is in operation, said muffler comprising a jacket adapted to surround said tool body in the vicinity of said exhaust port means and having partition means therein adapted to coact with said body to define first and second expansion chambers therebetween, said first expansion chamber receiving air discharging from said exhaust port means, said second expansion cHamber being connected to said first expansion chamber in continuous series flow relation by first orifice means external of said tool body, said jacket having at least one outlet port connecting said second expansion chamber with the atmosphere, and said first and second expansion chambers being arranged on laterally opposite sides of said tool body when said muffler is mounted thereon.
Claim 3
Dependent Claim
28 words
The muffler of claim 1, further characterized in that said expansion chambers are generally semi-cylindrical in form and are adapted to extend generally cicumferentially around said tool body.
Claim 4
Dependent Claim
25 words
The muffler of claim 1, further characterized in that said first orifice means is located substantially at one of the axial ends of said jacket.
Claim 5
Dependent Claim
75 words
The muffler of claim 1, further characterized in that said jacket has a generally cylindrical side wall portion spaced from the outer surface of said tool body when said jacket is mounted on said body, and said partition means comprises a pair of ribs on the inner surface of said side wall portion, said ribs having radially inner edges adapted to engage the body of said tool in sealing relation to define said expansion chambers.
Claim 6
Dependent Claim
71 words
The muffler of claim 4, further characterized in that said jacket has axially spaced end wall portions, said ribs extend axially from one of said end wall portions toward the other of said end wall portions, and at least one of said ribs terminates axially inwardly of the inner surface of said other end wall portion to define a gap therebetween, said gap comprising a portion of said first orifice means.
Claim 7
Dependent Claim
36 words
The muffler of claim 5, further characterized in that both said ribs terminate axially inwardly of said other end wall portion to define a pair of said gaps therebetween, said gaps comprising said first orifice means.
Claim 8
Dependent Claim
33 words
The muffler of claim 1, further characterized in that said first orifice means has an effective flow area of about 1.4 to about 1.5 times the flow area of said exhaust port means.
Claim 9
Dependent Claim
37 words
The muffler of claim 1, further characterized in that said jacket is formed in at least two, substantially symmetrical, separable parts, whereby said muffler may be easily mounted on or demounted from the body of said tool.
Claim 10
Dependent Claim
178 words
A muffler for attenuating the level of the sound generated by the operation of a pneumatic percussion tool or the like having an elongated body and exhaust port means in said body through which air under pressure discharges when said tool is in operation, said muffler comprising a generally cylindrical jacket adapted to be mounted on said tool body so as to enclose said exhaust port means, said jacket having a generally cylindrical side wall and axially spaced end walls adapted to coact with said body to define first and second expansion chambers therebetween, said first expansion chamber receiving air under pressure discharging from said exhaust port means and said second expansion chamber being connected to said first expansion chamber by first orifice means external of said tool body and arranged in series flow relation therewith, and said jacket having passage means in said second expansion chamber, one end of said passage means being connected to said second expansion chamber and the other end of said passage means being connected to an air outlet port in said jacket.
Claim 11
Dependent Claim
178 words
A muffler for attenuating the level of the sound generated by the operation of a pneumatic percussion tool or the like having an elongated body and exhaust port means in said body through which air under pressure discharges when said tool is in operation, said muffler comprising a generally cylindrical jacket adapted to be mounted on said tool body so as to enclose said exhaust port means, said jacket having a generally cylindrical side wall and axially spaced end walls adapted to coact with said body to define first and second expansion chambers therebetween, said first expansion chamber receiving air under pressure discharging from said exhaust port means and said second expansion chamber being connected to said first expansion chamber by first orifice means external of said tool body and arranged in series flow relation therewith, and said jacket having passage means in said second expansion chamber, one end of said passage means being connected to said second expansion chamber and the other end of said passage means being connected to an air outlet port in said jacket.
Claim 12
Dependent Claim
24 words
The muffler of claim 9, further characterized in that said passage means comprises at least one elongated passage communicating with said second expansion chamber.
Claim 13
Dependent Claim
17 words
The muffler of claim 10, further characterized in that said elongated passage extends axially in said jacket.
Claim 14
Dependent Claim
29 words
The muffler of claim 11, further characterized in that said elongated passage has a length approximately equal to 70 per cent of the length of said second expansion chamber.
Claim 15
Dependent Claim
26 words
The muffler of claim 10, further characterized in that said elongated passage is formed in a boss on the inner surface of said cylindrical side wall.
Claim 16
Dependent Claim
20 words
The muffler of claim 10, further characterized in that a pair Of said elongated passages are provided in said jacket.
Claim 17
Dependent Claim
35 words
The muffler of claim 14, further characterized in that said pair of elongated passages have upstream ends communicating with said second expansion chamber and comprising second orifice means interconnecting said second and third expansion chambers.
Claim 18
Dependent Claim
33 words
The muffler of claim 15, further characterized in that the effective flow area of said second orifice means is about 3/4 to 7/8 times the effective flow area of said first orifice means.
References Cited (Backward Citations)
US2166218A
Cited
US2128742A
Cited
GB496454A
Cited
US2789653A
Cited
US3224527A
Cited
US3554316A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |