US3396813A

US3396813A - Silencer or muffler and method of producing same

Info

Publication number: US3396813A
Application number: US633900A
Authority: US
Inventors: James R Hall
Original assignee: OLDBERG Manufacturing CO
Current assignee: APX GROUP Inc; OLDBERG Manufacturing CO
Priority date: 1967-04-26
Filing date: 1967-04-26
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13

Description

J. R. HALL Aug. 13, 1968 SILENCER OR MUFFLER AND METHOD OF PRODUCING SAME Filed April 26, 1967 4 Sheets-Sheet 1 IN VENTOR. JAMES R H441.

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Aug. 13, 1968 J. R. HALL 4 Sheets-Sheet 2 Filed April 26, 1967 INVENTOR. H JAMES R HALL -fl-..........-.,, A T TO/PA/5V m 99 e 6 a u 59 6 a J. R. HALL Aug. 13, 1968 SILENCER OR MUFFLER AND METHOD OF PRODUCING SAME Filed April 26, 1967 4 Sheets-Sheet 5 INVENTOR- JAMES A? //ALL 47 ram/5 y 8- 1968 J. R. HALL 3,396,813

SILENCER OR MUFFLER AND METHOD OF PRODUCING SAME- Filed April 26, 1967 4 Sheets-Sheet 4.

INVENTOR. JAMES A2 HALL Arrow/5y United States Patent 3,396,813 SILENCER 0R MUFFLER AND METHOD OF PRODUCING SAME James R. Hall, Toledo, Ohio, assignor to Oldberg Manufacturing Company, Grand Haven, Mich., a corporation of Michigan Filed Apr. 26, 1967, Ser. No. 633,900 16 Claims. (Cl. 181-61) ABSTRACT OF THE DISCLOSURE the ends of the rnufiler and being adjustable to varying angularities, the spherical regions of the bushings or nipples being welded to the ends of the mufiier shell.

The present invention relates to silencers or muffiers and method of producing same, the silencers or mutilers being particularly adapted for attenuating sound waves of exhaust gas streams from internal combustion engines of automotive vehicles. Sound attenuating muffler constructions have heretofore been fashioned with tubular outer shells with ends or end headers secured to the shells and bushings inserted in openings in the end headers and secured by welding or other suitable means.

In such constructions the bushings were necessarily disposed on an axis coincident or parallel with the longitudinal axis of the shell. The chassis of an automotive vehicle with which the mufiler may be used usually embodies several reinforcement or structural members and the engine exhaust conveying system including the sound attenuating device or mufiler must be fashioned to avoid interference with components of'the chassis construction. With prior muffler constructions wherein the bushings were aligned or parallel with the axis of the mufiler, many installations required special singularly-arranged end regions of the exhaust pipe and tailpipe requiring special bending of the exhaust pipe and tailpipe to accommodate a mufiler or silencer. Such arrangements are costly and necessitate extensive fabricating operations.

The present invention embraces the provision of a silencer or muffler construction embodying a tubular outer shell of one-piece construction fashioned with smoothly curved dome-shaped end regions of progressively reducing diameter, the terminals of the end regions defining circular openings to accommodate spherically-shaped regions of coupling members or bushings welded to the reduced end regions of the mufiler shell.

The invention embraces a method of fabricating a muffler involving progressively reducing an end region of a tubular shell to define a circular opening at the terminus of the reduced region, fitting a spherically-shaped portion of a coupling member into the opening, adjusting the angular position of the member relative to the shell, and welding the reduced end of the mufller to the spherically-shaped portion of the fitting.

Another object of the invention is the provision of a mufller construction embodying a one-piece muffler shell having dome-shaped end portions or sections terminating in circular openings arranged to accommodate gas inlet and outlet coupling members or bushings having ballshaped portions extending into the openings wherein one or both bushings provide support means for tubular gas passage means disposed in the mufiler shell and fashioned with perforations forming acoustic or sound attenuating couplings with the surrounding chamber for attenuating sound Waves.

Another object of the invention resides in a one-piece mufiler shell construction having curved end regions of progressively reduced diameter, each end region terminating in a circular edge defining an opening to receive a member having a ball-shaped configuration wherein a seal is effected by welding the circular terminal edge of the mufiler to the ball-shaped configuration of the member throughout the circumferential region of engagement.

Another object of the invention resides in a one-piece mufiier shell having an end section of progressively decreasing diameter terminating in a circular edge defining an opening, the opening adapted to accommodate a spherically-shaped portion of a coupling element adjustable to a desired angle and the element welded to the end region of the shell throughout the circular edge region.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a side elevational view, partly in section, of one form of mufiler construction illustrating coupling members in singularly-arranged positions with respect to the mufiler shell;

FIGURE 2 is an elevational view, partly in section, of a portion of the muffler construction shown in FIGURE 1 with a coupling member in axially aligned relation with the mufiler axis;

FIGURE 3 is an end elevational view of the arrangement shown in FIGURE 2;

FIGURE 4 is an elevational view showing a portion of a mufiier construction illustrating a coupling member angularly arranged with respect to the longitudinal axis of the mufiler;

FIGURE 5 is an elevational view, partly in section, of a portion of a muffler similar to FIGURE 2 illustrating a modified form of coupling member in angularly-arranged position relative to the mufiler shell;

FIGURE 6 is a longitudinal sectional view of a portion of a mufller shell and coupling member assembly wherein the coupling member provides support for a gas passage tube;

FIGURE 7 is a fragmentary sectional view of a muffler construction embodying a gas passage tube having a portion disposed in an end opening and welded to the muffler shell and a coupling member secured to an extremity of the gas passage tube;

FIGURE 8 is a longitudinal sectional view of a muffler construction illustrating a coupling member arranged to provide support for one end of a gas passage tube;

FIGURE 9 is a longitudinal sectional view of a form of mufiler construction wherein the couplings support a perforated gas passage tube, and

FIGURE 10 is a longitudinal sectional view of a portion of a mufller shell and coupling member assembly illustrating the gas passage tube extending into the coupling member.

Referring to the drawings in detail and initially to the construction shown in FIGURES 1 through 3, the sound attenuating or muffier construction 10 is inclusive of an outer shell 12 of one piece of metal fashioned of generally cylindrical tubular shape in which is disposed a cylindrically-shaped gas passage tube 14 of lesser diameter than the shell 12 and having a comparatively large number of openings 16 which form acoustic couplings with the elongated annular sound attenuating chamber 18 between the gas passage tube 14 and the shell 12.

In the form shown in FIGURES 1 and 2, spaced partitions 20 and 22 of annular shape are disposed in spaced relation lengthwise of the shell 12. Each of the partitions is fashioned with an inner flange 24 defining an opening in which is snugly fitted the gas passage tube 14 which may, if desired, be welded to one or both of the flanges. Each partition is provided with a peripheral flange 26 which is snugly fitted into the interior of the shell 12.

As illustrated in FIGURES 1 and 2, the end regions are of dome shape and in the method of fabrication the assembly of gas passage tube and partitions 20 and 22 is disposed within the cylindrical tubular shell 12 before the end region-s thereof are reduced in dimension to domeshaped configuration.

A feature of the invention is the provision of a onepiece mufiier shell 12 which is of tubular shape and cylindrical throughout its length prior to the reduction in dimension of its end regions. The shell 12 is of sheet metal of the seamless tube type or a tube of the Welded seam type. As shown in FIGURE 1, the end sections or regions 30 and 32 are configurated with an inward taper but each end region is smoothly curved and of gradually decreasing diameter from the cylinder portion to the end or terminus 34 to form a dome shape.

The curved end sections or regions 30 and 32 of the shell maybe swaged to dome shape by means of swaging dies, or the metal at these sections may be spun inwvardly to the configuration illustrated in the drawings. Thecurved end sections or rounded end regions of the shell may be fashioned by utilizing a tube of smaller diameter for the shell and expanding the tube to a larger diameter With rounded or dome-shaped end regions. This may be accomplished by employing a cavity mold or die shaped to the exterior configuration of the mufiler shell and expanding the tube wall outwardly by polyurethane forming. The terminus of each end section is a circular edge defining a circular opening, the circular or terminal edge 34 of the opening lying in a plane normal to the longitudinal axis of the tubular shell 12. By reason of the sWa-ging or spinning operations in progressively reducing the end regions or sections of the muffler shell to a dome shape, the metal may be progressively thickened slightly.

The invention embraces the provision of a nipple, bushing or coupling for each end of the mufiier shell joined to the terminus of the reduced end portions of the muffler shell. The couplings or bushings 38 and 40 for the ends of the mufiler shell are of generally similar construction. As shown in FIGURES 1 and 2, the bushing 38 is of a character for use at the gas inlet end of the muffler and comprises a generally tubular-shaped member of circular cross section having a central or intermediate portion 42 which is integrally joined with an adjacent cylindrical end region 44 of slightly larger internal diameter than the portion 42 to receive the end region of an exhaust pipe or exhaust conveying tube connected with the exhaust system of an internal combustion engine.

The exhaust pipe (not shown) is telescoped into the cylindrical portion 44 and a clamp means (not shown) of conventional construction surrounds the portion 44 near its end region. The Wall of the portion 44 near the end thereof is provided with a plurality of slots 48 to enable the clamp to draw the end regions of the portion 44 into tight engagement 'with an exhaust pipe. The coupling or bushing 38 is fashioned at its opposite end with a spherically-shaped portion 50 of a diameter to be snugly received within the circular opening defined by the terminal region of the reduced portion 30 of the muffier shell.

As the exterior configuration of the portion 50 is spherical or ball shaped, the coupling member 38 may be adjusted to various angular positions with respect to the longitudinal axis of the muffler shell 12.

As shown in FIGURE 1, both the inlet and outlet couplings or bushings 38 and 40 are angularly-"trranged with respect to-the longitudinal axis of the shell 12. The circular terminal edge 34 defining the opening in the domeshaped portion 30 of the mufiier shell is welded as at 52 in a circular path throughout the circumference of the ball shape portion 50 to provide a gas tight seal between the muffler shell 12 and the coupling 38, the welding further serving to maintain the predetermined angular relationship of the coupling 38 With respect to the shell.

The coupling or bushing 40 at the gas outlet end of the mufiler is fashioned with a cylindrical portion 56, and a tailpipe (not shown) may be telescoped over the exterior of the cylindrical portion 56 and conventional clamp means may be provided embracing the tailpipe to draw the latter into a snug engagement with the portion 56. Adjacent the portion 56 is a cylindrical region 60 of a diameter slightly larger than the portion 56 providing an abutment or shoulder 62 to limit the lengthwise position of the tailpipe telescoped over the portion 56. The coupling or bushing 40 is fashioned with a spherically-shaped portion 64 of a diameter to be snugly received within the circular terminal edge region 34 of the curved portion 32 of the muffler.

FIGURES 2 and 3 illustrate a portion of the mufiier 10 and the inlet coupling or fitting 38 showing the axis of the coupling aligned with the axis of the muffier. It is to be understood that the outlet coupling 49 may likewise be arranged whereby its longitudinal axis is aligned with the axis of the muffler 10 in the same manner.

As particularly shown in FIGURE 1, the curved end regions or dome-shaped regions 30 and 32 of the muffler shell 12 are smoothly curved and progressively reduced in diameter toward the circular terminal edges 34, the edges defining circular openings in the ends of the shell. The circular edge regions 34 snugly receive the ballshaped configurations 50 and 64 of the respective couplings 38 and 4t) and the edges 34 are welded to the peripheries of the ball-shaped configurations of the couplings by the vcircular welds 52 and 66 coincident with the edges 34. The curved or dome-shaped portions 30 and 32 of the mufiler shell are preferably of a configuration as illustrated in FIGURE 1 but it is to be understood that the particular shape of curvature may be varied or modified dependent upon the length of space desired between the headers or partitions 20 and 22 and the end couplings 38 and 40, the diameter of the muffler shell, and the diameters of the couplings or bushings 38 and 40.

An important feature of the construction is that each curved portion 30 and 32 terminates in a circular edge 34 so that when the edge regions are welded to the couplings as at 52 and 66, the Welds will be circular as they are coincident with the edges. These structural features facilitate forming the circular welds by production methods and assures a gas tight seal between the ball or spherically-shaped portion of each coupling with the curved portions 30 and 32 at the ends of the shell. It will be apparent that the couplings 38 and 40 may be arranged in various angular positions but each of the welds 52 and 66 will be of circular contour irrespective of the angularities of the couplings with the muffler shell.

FIGURE 4 illustrates a modified configuration for the curved end region of a muffier shell 68. In this form of construction, the gas inlet coupling or fitting 70 is fashioned with a ball-shaped or spherically-shaped configuration 72, the center 74 of generation of the ballshaped portion 72 being displaced laterally from the longitudinal axis BB of the muffler 68. The curved or dome-shaped portion 76 at the. end region of the muffier shell 68 is fashioned to terminate in a circular edge 78 defining an opening of a dimension to snugly receive the spherically-shaped exterior configuration 72 of the tubular coupling 70. The circular terminal edge 78 of the curved portion 76 of the mufiier shell is welded as at 80 to the ball-shaped portion 72 throughout its circumference to provide a circular weld.

In the arrangement shown in FIGURE 4, the coupling or fitting 70 may be angularly-arranged with respect to the muflier shell 68 and displaced from the axis of the mufiier shell to accommodate particular installations of the mufiler with an exhaust system of an internal combustion engine of an automotive vehicle. The outlet or opening of the coupling 70 within the muflier shell may be defined by an outwardly flared terminus or flange 82 to facilitate exhaust gas flow into the mufller shell with a minimum of whistling noise.

Disposed in the mufiler shell 68 is a gas passage tube 84 supported by a partition or header 86, the gas passage tube being fashioned with a large number of small perforations or openings 90 providing acoustic couplings between the gas passage tube and the annular sound attenuating chamber 88 surrounding the tube.

It is to be understood that the mufiier 63 may be fashioned at its opposite end to accommodate an outlet coupling secured to a similarly curved portion of the shell in the same manner as the inlet coupling 70.

FIGURE 5 illustrates a gas inlet coupling 38a having a ball-shaped portion 50a secured by welding 52a to the circular terminal edge of a curved or dome-shaped portion 30a of a 'mufller shell 12a. In this form the ball configuration 50a terminates in a circular edge 94 lying in a plane substantially normal to the longitudinal axis CC of the muffler shell 12a. The coupling or fitting 38a is similar to the fitting 38, shown in FIGURE 1, but with the portion 96, indicated in broken lines, removed from the portion of the fitting extending into the mufiler shell 12a.

Through this arrangement the exhaust gas delivered from the opening defined by the circular edge 93 is more nearly directed axially of the mufiier shell 12a toward the gas passage tube 14a. With the arrangement shown in FIGURE 5 the resistance of deflecting the exhaust gases toward the gas passage tube 14a is minimized. The fitting 38a is adapted to accommodate an exhaust pipe (not shown) for conveying exhaust gases into the muffier. It is to be understood that an outlet fitting of the same character as illustrated ,at 38a may be secured to a curved portion at the other end of the mufiier shell 12a.

FIGURE 6 illustrates a modified form of the invention wherein a gas conveying coupling provides support for a gas passage tube. The muffler shell 12b is provided with a curved or dome-shaped portion 30b terminating in a circular terminal edge 34b defining an opening.

A tubular coupling or bushing fitting 100 is fashioned with a sperically-shaped or ball portion 102 which snugly fits in the opening defined by the circular edge 34b of the curved end region 3% of the muflier shell. The spherically-shaped or ball-shaped portion 102 is fashioned with a cylindrical extension 104 disposed within the muffler shell 12b.

A gas passage tube 106, disposed in the shell 12b, has an end region 108 in telescoping or overlapping relation with the cylindrical portion 104 of the coupling or bushing 100. The overlapping portions of the coupling and gas passage tube may be welded together as shown at 110. The gas passage tube 106 has a large number of small openings 112 which form acoustic couplings with the annular chamber 114 surrounding the gas passage tube for attenuating sound waves. Through engagement of the end of the gas passage tube with an extension of the coupling 100, one end of the gas passage tube is supported by the coupling or bushing 100.

The other end of the gas passage tube 106 may be supported by a partition, such as a partilion of the character illustrated at 22 in the form of the invention illustrated in FIGURE 1. In assembling the arrangement shown in FIGURE 6, the gas passage tube 106 is Welded to the extension 104 of the coupling or bushing prior to its assembly within the muffier shell 12b. In this form, the

axes of the coupling and the gas passage tube 106 are in aligned relation.

Upon positioning of the ball-shaped portion 102 in the circular opening defined by the circular edge 34b of the muffler shell, the terminal edge 34b of the mufiler shell 12b is welded as at 116 throughout the circumference of the exterior surface of the spherically-shaped portion 102 of the coupling 100 :to form a gas tight joint between the coupling and the muffler shell. The coupling 100 is adapted to accommodate the end region of a conventional exhaust pipe for conveying exhaust gases into the mufiler. A coupling similar to the coupling 100 may be mounted in theoutlet region of the muffler shell and the gas passage tube supported thereby in the manner illustrated in FIGURE 6.

FIGURE 7 illustrates another form of the invention. In this form an end region of the muffler shell 120 is fashioned with a curved or dome-shaped portion 122 terminating in a circular opening defined by a circular edge 123. Disposed within the mufiler shell 120 is a cylindricallyshaped gas passage tube 124 having a large number of small openings 125 which form acoustic couplings with an annular chamber 126 surrounding the gas passage tube. An end of the gas passage tube is provided with a spherically-shaped or ball-shaped portion 128 which snugly fits within the circular opening defined by the circular edge 123 at the end of the muffler shell 120.

The spherically-shaped portion 128 terminates in a circular opening. A tubular coupling or bushing 130 is fashioned with a spherically-shaped or ball-like portion 132, the exterior diameter being of a dimension to snugly fit the circular opening defined by the terminal edge of the curved or ball-shaped portion 128 of the gas passage tube.

The circular terminal edge of the ball-shaped portion 128 is welded .as at 134 to the ball shaped portion 132 of the coupling throughout its periphery. The terminal edge 123 of the dome-shaped portion 122 of the mufi le-r shell 120 is welded as at 136 to the ball-shaped portion 128 throughout its periphery.

The

circular weldings

134 and 136 provide gas tight or sealed joints between the coupling 130 and the gas passage tube, and between the gas passage tube and the end region of the muffler shell 120. The coupling 130 may be angularly adjusted with respect to the axis of the gas passage tube 124 as desired and welded in adjusted position. In order to enhance the flow of exhaust gases from the coupling 130 into the gas passage tube, the end of the coupling within the ball-shaped portion 128 of the gas passage tube may be terminated in a circular edge 138 normal to the axis of the gas passage tube as illustrated in the drawings.

The portion 140 of the ball-shaped configuration 132. on the coupling or bushing, illustrated by broken lines, may be removed to facilitate diversion of the gase flowing through the coupling 130 toward the gas passage tube 124 with a minimum of flow resistance. In the form of the invention shown in FIGURE 7, an end of the gas passage tube is supported by an end region of the mufiier shell 120, and the .angularly disposed coupling or bushing 130, welded to a ball-shaped portion of the gas passage tube, is thus supported by the gas passage tube.

FIGURE 8 shows a further modification of the invention. In this form the muffler shell 144 is fashioned with a curved or dome-shaped end portion 146 terminating in a circular edge 147 defining a circular opening at the terminus of the dome-shaped portion 146-. A gas inlet coupling or bushing 148 is fashioned with a sphericallyshaped or ball-like portion 150 which snugly fits into the circular opening defined by the terminal edge 147, the terminal edge of the dome-shaped portion 146 of the muffler shell being welded as at 152 throughout the periphery of the ball-shaped portion 150 to provide a gas tight joint between the coupling 148 land the muffler shell 144.

Disposed within the mufiler shell 144 is a header or partition 154 which supports one end of a cylindrical gas passage tube 156, the latter being fashioned with a large number of small openings 158 which form acoustic couplings with an annular chamber 160 surrounding the gas passage tube. In the form shown in FIGURE 8, the coupling or bushing 148 is fashioned with a portion 162 of an internal diameter to snugly receive an end portion of the gas passage tube 156 whereby the inlet end of the gas passage tube is supported by the coupling or bushing 148. The overlapping contiguous regions of the gas passage tube and the coupling 148 may be spot-welded together as shown at 164.

The inlet coupling 148 is adapted to telescopingly receive an exhaust pipe (not shown) for conveying exhaust gases into the mufiler construction.

An outlet fitting 168 is fashioned with a sphericallyshaped or ball portion 178 which fits in the circular opening defined by a circular edge 171 at the terminus of the curved or dome-shaped region 172 at the outlet end of the mufller shell. The terminal edge defining the opening receiving the ball-shaped portion 170 is welded as at 174 throughout the periphery of the ball-shaped portion to form a gas tight shell or joint.

'FIGURE 9 illustrates a form of the invention wherein the gas passage tube of the mufiler construction is supported by the couplings or bushings at the inlet and outlet ends of the muffler. The muffier shell 180 is fashioned with dome-shaped or curved end regions 181 and 182 terminating in circular edges 183 and 184 defining circular openings. An inlet coupling or bushing 185 is fashioned with a spherically-shaped or ball-like portion 186 snugly fitting into the circular opening defined by the circular edge 183. Disposed within the mufller shell 180 is a gas pasage tube 188 having small openings 189 forming acoustic couplings with an annular chamber 190.

The axis of the coupling or bushing 185 is aligned with the longitudinal axis of the gas passage tube 188, the ballshaped portion 186 of the coupling being welded as at 192 throughout its periphery to the terminal end or edge of the dome-shaped portion 181 of the muffier. The coupling or bushing 185 is provided with a cylindrical region 194 of reduced diameter to snugly yet slidably accommodate an end region 195 of the gas passage tube 188.

The contiguous regions of the cylindrical portion 194 and the gas passage tube 188 are spot welded together as shown at 196. In this manner, the inlet coupling or bushing 185 supports one end of the gas passage tube 188.

A gas outlet coupling or bushing 200 is disposed at the opposite end of the mufiler shell and has a sphericallyshaped or ball-like configuration 202 extending into a circular opening defined by the circular edge 184- at the terminus of the dome-shaped end 182 of the mutfier shell. The longitudinal axis of the coupling 200 is aligned with the axis of the gas passage tube 188. The coupling 200 is fashioned with a cylindrically-shaped portion 204 of an internal diameter to snugly receive the end region 206 of the gas passage tube 188, the overlapping regions of the cylindrical portion 204 and the end portion 206 of the gas passage tube being spot welded together as at 208.

The ball-shaped portion 202 of the coupling 200 is welded as at 210 throughout its periphery to the terminal end of the dome-shaped portion 182 to form a gas tight or sealed joint. The outlet coupling 200 is adapted to telescopingly receive a tailpipe or other conventional gas conveying tube (not shown). Thus the respective ends of the gas passage tube 188 are welded to and supported by the couplings or bushings 185 and 200' and the couplings in turn welded to the one piece muffier shell 180 by the peripheral welds 192 and 210.

It will thus be seen that in all forms of the invention, the welds between the dome-shaped ends of the one piece rnufiier shell and the inlet and outlet couplings or, as shown in FIGURE 7, between a ball-shaped end region of the gas passage tube and a couplings are circular welds irrespective of the angularities of the couplings or bushings with respect to the mufiier shell. By

sears providing a method of construction wherein the welding regions are circular, high speed production of welding may be attained assuring a gas tight mufiier construction.

FIGURE 10 illustrates a construction similar to FIG- URE 5. In the arrangement shown in FIGURE 10, the muffler shell is fashioned with a dome-shaped end region 30c. The inlet coupling 380 is formed with a ballshaped configuration 500 which extends into the circular opening defined by the terminal edge of the dome-shaped end region 300 of the mufiier shell and is welded to the circular terminal edge as at 526. A gas passage tube 212 is disposed interiorly of the shell 12c and is of a small diameter whereby the end 214 of the tube 212 extends into the ball-shaped configuration 500. The gas passage tube 212 may be supported by one or more bafiles 216, one being illustrated in FIGURE 10. The wall of the gas passage tube at the right-end side of the bafile 216 is fashioned with a comparatively large number of small openings 218 forming acoustic couplings with the annular space between the gas passage tube 212 and the mufiier shell 12c. By extending the gas passage tube 212 into the ball-shaped configuration 50c, whistling noises caused by the moving exhaust gas stream are substantially reduced.

In the forms of the invention shown in FGURES 1, 2, 4, 5, 7 and 10 the tubular couplings or bushings may be angularly adjusted to accommodate the angularities of various gas conveying pipes or tubes thus readily adapting the muifier to various installations without special couplings for each installation. In the forms shown in FIGURES 6, 8 and 9, the couplings may be employed to support one or both ends of a gas passage tube and thereby eliminate one or both partitions or headers in the muiller.

In all forms of muffler construction illustrated herein, the annular space or region between the gas passage tube and the muffler shell may be filled with sound absorbing or sound damping material such as fibrous glass or other similar material which is resistant to high temperatures.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehendnig all variations thereof.

I claim:

1. A mufiier for use with the exhaust system of an internal combustion engine including a one-piece tubular shell having an integral end region of dome-shaped configuration terminating in a circular edge defining an opening, and a tubular fitting having a spherically-shaped portion extending into the opening and disposed adjacent the circular edge, the circular edge being joined to the adjacent spherically-shaped portion of the tubular fitting by welding to provide a fluid tight joint between the shell and the tubular fitting.

2. The combination according to claim 1 including tubular gas passage means mounted within the shell.

3. A muffler for use with the exhaust system of an internal combustion engine including a one-piece tubular shell having an integral smoothly curved end region of progressively decreasing diameter terminating in a circular edge defining an opening, a tubular coupling member having a spherically-shaped portion extending into the opening and disposed adjacent the circular edge, the circular edge being joined to the adjacent portion of the tubular coupling member by welding to provide a fluid tight joint between the shell and the tubular member.

4 The combination according to claim 3 including a gas passage tube mounted within the shell, said gas passage tube having open areas providing acoustic couplings with a region between the shell and the gas passage tube.

5. A mufiier for use with the exhaust system of an internal combustion engine including a one-piece tubular shell having integral smoothly curved end regions of progressively decreasing diameter providing dome-shaped configurations, each configuration terminating in a circular edge defining a circular opening, tubular gas inlet and outlet fittings for the respective ends of the shell, each of said fittings having a spherically-shaped portion extending into the adjacent opening, the circular edges being joined to the adjacent spherically-shaped portions of the respective fittings by welding to provide fluid tight joints between the shell and the fittings.

6. A muflier for use with exhaust system of an internal combustion engine comprising, in combination, a onepiece tubular shell having an integral end region of domeshaped configuration terminating in a circular edge defining an opening, tubular means having a sphericallyshaped portion, the spherically-shaped portion of the tubular means being disposed in the opening and snugly engaging the circular edge, the circular edge at the end of the shell being joined to the spherically-shaped portion of said tubular means by welding the circular edge throughout its circumference to the spherically-shaped portion to provide a fluid tight joint between the shell and the tubular means.

7. The combination according to claim 6 wherein the tubular means is angularly arranged with respect to the longitudinal axis of the shell.

8. The combination according to claim 6 wherein both end regions of the tubular shell are dome-shaped configurations terminating in circular edges defining openings, and tubular means for each end of the shell, both tubular means having spherically-shaped portions joined by welding the circular edges to the spherically-shaped portions.

9. A muffier comprising, in combination, a one-piece thin-walled cylindrically-shaped shell, a gas passage tube of lesser diameter mounted within the shell, at least one end region of the shell being of progressively reduced diameter providing a dome-like configuration terminating in a circular edge defining an opening, a tubular member having a spherically-shaped portion fitting within the opening and snugly engaging the circular edge, said tubular member being adapted to be angularly disposed with respect to the axis of said shell, and fused metal bonding the circular edge of said dome-shaped configuration to the spherically-shaped portion of the tubular member throughout a peripheral region of the spherically-shaped portion forming a fluid tight joint and securing the tubular member in angularly disposed position.

10. A mufiler for use with the exhaust system of an internal combustion engine comprising, in combination, a one-piece cylindrically-shaped thin-walled metal shell, the end regions of said shell being of dome-shaped configuration, each dome-shaped configuration terminating in a circular edge defining an opening, a tubular gas inlet fitting for one end of said shell, a tubular gas outlet fitting for the other end of said shell, each of said fittings having a spherically-shaped portion extending into the opening at an end of the shell and snugly engaging the circular edge, said spherically-shaped portions of said fittings being welded to the circular edge regions of dome-shaped portions defining the openings to form gas tight joints, and a gas passage tube disposed within said shell, the wall of said gas passage tube having small openings therein forming acoustic couplings with a space surrounding the gas passage tube.

11. The combination recited in claim 10 including a partition in said shell providing support means for the gas passage tube.

12. The combination according to claim 10 including a partition in said shell providing support means for an end region of the gas passage tube, the other end of said gas passage tube being in engagement with and supported by one of said tubular fittings.

13. The combination according to claim 10 wherein the respective ends of the gas passage tube are in engagement with said inlet and outlet fittings whereby the gas passage tube is supported by said fittings.

14. A mufiier comprising, in combination, a one-piece tubular shell of substantially cylindrical configuration, an end region of said tubular shell being of progressively reduced diameter providing a dome-shaped configuration terminating in a circular edge defining an opening, a tubular coupling member having a spherically-shaped portion snugly fitting within said opening, fused metal bonding the circular edge region of said dome-shaped configuration to the spherically-shaped configuration to form a fluid tight joint, the tubular coupling member having a cylindrical extension Within the shell of lesser diameter than the diameter of the exterior surface of the sphericallyshaped configuration and integrally joined with the spherically-shaped configuration, and a gas passage tube disposed within the shell having an end region in overlapping relation with said extension providing support means for the gas passage tube, said gas passage tube having a plurality of openings in the wall thereof providing acoustic couplings with the space surrounding the gas passage tube.

15. The method of producing a mufller comprising the steps of progressively reducing an end region of a thin walled tubular shell to form a dome-shaped configuration terminating in a circular edge defining an opening, positioning a spherically-shaped portion of a tubular coupling in the circular opening with the circular edge snugly engaging the spherically-shaped portion, and welding the circular edge to the spherically-shaped portion throughout its periphery to form a gas tight seal.

16. The method according to claim 15 including the step of adjusting the tubular coupling at an angle with respect to the longitudinal axis of the tubular shell prior to welding the circular edge to the spherically-shaped portion.

I References Cited UNITED STATES PATENTS 1,838,249 12/1931 Brown 285286 1,972,065 8/1934 Noblitt 18l-48 2,035,923 3/1936 Scarritt 181--48 2,485,392 10/1949 Leadbetter 18148 2,553,326 5/1951 Manning 18-1-61 2,598,756 6/1952. Brightly et a1. 18161 2,872,998 2/1959 Tinker 181--61 3,159,239 12/1964 Andrews 18161 3,274,678 9/1966 Andrews 29471.1

FOREIGN PATENTS 877,911 9/ 1942 France.

ROBERT S. WARD, JR., Primary Examiner.