Abstract: A vehicular exhaust system muffler fabrication method including using mechanical lock joints for joining the end tubes to the flow tubes. Each end tube has one end whose outer diameter is selected such that the one end may be loosely, telescopically, and overlappingly fitted within the adjacent end of the adjacent flow tube. Each of the overlapped ends of the end tubes and the flow tubes are mechanically locked together by a circumferential skewed bead which is formed in the overlapped ends, with the plane of the skewed bead being at an angle less than 90.degree. with respect to the central longitudinal axis of the overlapped ends. The muffler fabrication method also includes the use of other mechanical lock joints to lock the end tubes within apertures in the end panels of the muffler. Each of these other lock joints includes a continuous, circumferential bead formed in the end tube and in the annular flange, which is integral with the end panel and which extends along the end tube.

Abstract: A vehicular exhaust system muffler including a mechanical lock joint for joining the end tubes to the flow tubes. One end of each end tube has an outer diameter selected such that the one end may be loosely, telescopically and overlappingly fitted within the adjacent end of the adjacent flow tube. The overlapped ends of the end tubes and the flow tubes are mechanically locked together by a circumferential skewed bead formed in the overlapped ends, where the plane of the skewed bead is at an angle less than ninety degrees with respect to the central longitudinal axis of the overlapped ends. This mechanical locking maintains the relative axial positions of the overlapped ends and resists relative movement between the overlapped ends and between the internal panels and the wrapper due to the application of torsional and axial forces that the tubes experience during the assembly of the muffler.

Abstract: An apparatus for forming a muffler mechanical lock joint, and the resulting assembly. An end panel is loaded in a die structure. Die segments on chuck jaws hold an end panel flange. A tube is loaded over a wedge, punch segments, a punch segment holder, barrel and wedge drive rod. The panel, chuck and die structure are driven over the tube. Each punch segment includes a protrusion punch and a bead punch segment. The wedge is axially pulled. Guiding and guided members on the punch segments and segment holder allow only radial movement of the segments. Axial pulling of the wedge thereby causes radial expansion of the punch segments. The radially expanded punch segments form a plurality of protrusions in the tube and panel flange, and an adjacent bead.

Abstract: In a vehicular exhaust system muffler, a mechanical tube and end panel joint. A bead extends about the tube. The bead is integral to the tube, annular, and radially outwardly extending. An annular flange extends along the tube and abuts the bead. The flange is integral to the end panel. A plurality of integral, interlocking protrusions are simultaneously deformed into the tube and flange. The bead, flange and protrusions totally mechanically join the tube and end panel.

Abstract: A tubular assembly embodying a pin and slot connection between two thin wall tubular members having end portions disposed in telescopic relation with respect to one another. The outer tubular member having the slot also has an opening extending therethrough in closely spaced relation to its edge in a position generally alongside the slot providing an axially elongated wall portion between the opening and slot. The wall portion has a fixed integral outer end spaced axially outwardly of an intermediate locking section of the slot and a fixed integral inner end spaced axially inwardly of the intermediate locking section of the slot and is operable to resiliently deflect laterally when the pin is moved axially inwardly through the slot to thereby permit the locking section of the slot to expand in its width dimension and permit yielding passage of the pin axially thereby into received relation within the inner section of the slot.