US 3743048 A
A one-piece hollow enclosure slidably or fixedly mounted over the cooperating housing and barrel of an explosive hand-held device, such as a powder actuated fastener driving tool, reduces the noise of an exploding charge, provides good heat dissapation, and facilitates barrel opening and closing. High pressure gases are allowed to exhaust with gradual expansion, reversal of general flow direction, and turbulance.
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Description (OCR text may contain errors)
United States Patent [191' Bakoledis SOUND MUFFLER FOR EXPLOSIVE DEVICES  Inventor: Andrew G. Bakoledis, Clinton,
Conn.  Assignee: USM Corporation, Boston, Mass.  Filed: May 23, I972  Appl. No.: 256,087
 U.S. Cl 181/53, 181/33 K, 60/261  Int. Cl. F0ln 1/08  Field of Search 181/33 K, 36 R, 36 A, 181/36 D, 49, 53; 89/14 B, 14 D, 14 E; 60/261, 26.11
 References Cited UNITED STATES PATENTS 1,115,704 11/1914 Manes 181/36 A UX 2,401,190 5/1946 Reynolds 2,789,653 4/1957 Fannen 181/36 A UX [451 July 3, 1973 3.204.400 9/1965 Kvace "60/261 FOREIGN PATENTS OR APPLICATIONS 835.713 5/1960 Great Britain 181/36 A 932.373 7/1963 Great Britain 181/36 A Primary Examiner-Richard B. Wilkinson Assistant Examiner-John F. Gonzales Anorney-PCarl E. Johnson et a1.
[5 7] ABSTRACT A one-piece hollow enclosure slidably or fixedly mounted over the cooperating housing and barrel of an explosive hand-held device, such as a powder actuated fastener driving tool, reduces the noise of an exploding charge, provides good heat dissapation, and facilitates barrel opening and closing. High pressure gases are allowed to exhaust with gradual expansion, reversal of general flow direction, and turbulance.
5 Claims, 4 Drawing Figures SOUND MUFFLER FOR EXPLOSIVE DEVICES BACKGROUND OF THE INVENTION Need exists for a means to reduce the; noise created as by an exploding cartridge employed in certain industrial devices such as fastener driving tools. Frequently they are operated within an enclosure such as a small room or semi-enclosed space. The noise can then be is especially concerned. While the tool is of the type deafening to anyone nearby, especially since repeat op- SUMMARY OF THE INVENTION It is a primary object of this invention to provide a sound-reducing cover of simple construction for mounting on an explosive device.
A more specific object of this invention is to provide a close fitting muffler for an explosive fastener driving tool, the muffler being easily mountable and demountable, and permitting cartridge loading and ejection with ease.
To these ends, and as herein shown, the novel muffler comprises a one-piece hollow cover preferably of metal, a first main tubular portion of the cover being formed of substantially uniform diameter to closely fit the major portion of a barrel and/or its housing, this main portion being adapted to receive the gases of explosion at the barrel breech end, and a second tubular portion of less volume and cross sectional dimension extending parallel and largely coextensive with the main cover portion, the first and second portions having no intervening vents except as may be defined by portions of the barrel and the housing whereby the gases in the barrel are primarily expelled from the first and into the second portion with turbulance and caused to reverse their general direction of flow to be exhausted from the second portion at an outer exit adjacent to said barrel breech end.
DESCRIPTION OF THE DRAWINGS The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment, and with reference to the accompanying drawings, in which:
FIG. I is a view in side elevation, and partly in axial section, of an explosive fastener driving tool in breechclosed condition and on which a sound muffler has been mounted;
FIG. 2 is a bottom view of a muzzle portion of the tool shown in FIG. 1;
FIG. 3 is a section taken on the line III-Ill of FIG. 1, and
FIG. 4 is a view in side elevation corresponding with FIG. 1 except that the breech is shown open.
DESCRIPTION OF PREFERRED EMBODIMENT FIG. 1 shows a typical powder actuated tool generally designated 10 for driving fasteners and having a sound muffler 12 (FIGS. l-4) with which this invention having an axially movable barrel 14 the barrel carrying a driving ram 18 and having axial guidance in a housing 20, it will be understood that the muffler 12 is itself of simple construction and adapted to fit snugly over any housing (such as 20) of an explosive device whether used for driving fasteners or otherwise.
In this case the barrel 14 may, for instance, be moved axially to a breech open position as shown in FIG. 4 by means of a muzzle portion 22 coupled to the barrel and shifting it relative to the housing 20. This allows the muffler 12, which had enclosed a housing opening 24 affording access for breech loading of a cartridge C (FIG. 1 to slide forwardly, i.e., toward the muzzle end with the portion 22 thereby enabling removal of a spent cartridge. In breech-closed and locked condition an end of the muffler 12 is retained axially against an end of the housing by abutment with a collar 26 of the muzzle portion 22. Alternatively, the collar 26 may be a part of the barrel 14 as shown in FIG. 1. An O-ring 27 (FIG. 1) retains the muffler to the barrel so the breech can be closed by merely sliding the muffler.
The muffler 12, preferably of one-piece metal construction, comprises a main tubular cover portion 28 of substantially uniform diameter to closely and slidably fit on the barrel and the housing, and a second tubular portion 30 of less volume and cross sectional dimension. The portion 30 is generally parallel and largely coextensive with the main cover portion 28. It will be understood that the muffler portions 28,30 are constantly in open communication and have no intervening vents except as may be defined by the barrel and the housing or parts associated therewith.
When the cartridge C is exploded in the barrel breech, the breech being in closed condition as in FIG. 1, propelled gases acting on the ram 18 quickly attain high pressure and velocity to drive it axially. The gases pursue any available escape route, primarily following the easiest path, that is, proceeding muzzleward in the main cover portion 28, within the barrel bore and usually through a longitudinal barrel slot 32 (FIG. 1) and a housing slot34. The latter may, as in this case, accommodate a key 36 of the type adapted, in the course of recocking the tool, to return the ram 18 to its ready-to-fire position. The gases thence proceed into the tubular portion 30, may rebound from contact with an inclined inner wall 38 (FIG. 1) of that portion, and be reversed in direction as well as with turbulance.
Though not an essential part of the muffler 12, a desirable additional feature is a baffle 40 (FIGS. 1, 3, and 4) which, as shown, may be semi-circular in cross section and secured in alignment within the portion 30 as by a screw 42 to a part of the tool, for instance, the housing 20. The baffle 40 aids in creating flow turbulance and retarding the exhausting gases prior to exiting, at low velocity and much reduced temperature at a muffler port 44 at the breech end of the portion 30. Also, the baffle 40 serves as a guard preventing interference between the muffler 12 and the key 36, and acts as a guide preventing relative rotation of the muffler on the housing.
It is estimated that of the exhaust gases perhaps on the order of about percent exit at the port 44 adjacent to a finger guard 46. This flow is not fast nor hot and hence is in no way injurious to an operator. Approximately 10% of the exhaust may axially escape about the breech end of the muffler portion 28 covering the access opening 24, and about another may escape circumferentially at the cut-away locality 48 (FIGS. 1, 2, and 4) of the muffler portion 28. These 10 percent discharges, though possibly of higher temperature than that at the port 44, are in no way troublesome to the operation.
It will be appreciated from the foregoing that the gases of explosion are distributed by the muffler 12, that their major portion is directed thereby in a generally U-shaped course which not only causes reversal of their initial direction, but effects turbulance. The net result is considerable reduction in the level of noise and good heat dissipation. Moreover, when the tool 10 is being employed in the outdoors or relatively unconfined areas where noise may not be objectionable, the muffler may be easily removed if desired.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:
l. A muffler for use with an explosive device comprising a housing and a barrel mounted therein, said muffler including a hollow cover, a first main tubular portion of the cover being of substantially uniform diameter to closely fit the major portion of the barrel and/or its housing and adapted to receive the gases of explosion at its breech end, and a second tubular portion of less volume and cross sectional dimension extending parallel and partly coextensive with the first main tubular portion, the first and second portions communicating throughout their coextensive length except as partial interruption to flow may be provided by portions of the barrel and/or the housing therein, said first portion being open at its breech and muzzle ends, and said second portion being closed at its muzzle end and open at its breech end whereby the major portion of the explosive gases are initially directed muzzleward in the first main tubular portion and then directed into the second tubular portion for reversal and emission therefrom at its breech end.
2. A muffler as in claim 1 wherein the first tubular portion has slidable, close fitting relation to the barrel housing to enable an access opening in the latter to be alternatively wholly covered and at least partly uncovered.
3. A muffler as in claim 1 wherein said closed muzzle end of the second tubular portion is formed with a wall which extends angularly outwardly from the first tubular portion and away from the muzzle of the device.
4. A muffler as in claim 1 wherein a baffle of semicircular section is mounted in the second tubular portion and generally aligned therewith.
5. A muffler as in claim 1 wherein the muzzle end of the muffler is formed as a collar having close fit with the barrel, a shoulder formed on the barrel abuts the muzzle end of the muffler, and an O-ring retains the muffler to the barrel so that the barrel can be axially moved into breech closed position by manually sliding the muffler.