Donaldson Comapny, Inc.

Timothy A Bethke

Wayne M Wagner

Steven D Schmeichel

Gary John Rocklitz

Douglas E Flemming

John R Hiemstra

John S Wiese

John A Campbell

William L Burchett

A muffler assembly includes an inner outlet tube having a tubular portion, a frusto-conical portion and a flange portion having an expanded orifice facing the outlet of an inlet tube. Both the outlet tube and inlet tube extend within a chamber defined in an outer housing. The chamber is divided into two or more subchambers by a baffle which extends between the outlet tube and the housing. One or more holes in the baffle improve the sound attenuation characteristics of the muffler. The invention also comprehends a novel blank used in forming the outlet tube, and three alternative methods which may be used to form the outlet tube.

Muffler assembly and method of manufacture

A clamp suitable for joining a pair of tubular members, e.g., commercial truck exhaust pipes. One clamp (70) according to the invention includes an S-shaped band (72) having a pair of forward curved portions (76) on either side of a reverse curved portion (78). Attached to each forward curved portion (76) is a reinforcing bar (74) preferably forming a pair of D-shaped holes (75) suitable for receiving 'half-carriage' bolts (100). The band (72) is preferably formed from Type 409 stainless steel to reduce costs. A fully preformed (cylindrical) embodiment (120) and flat embodiment (130) are also disclosed.

Apparatus for coupling tubular members

The present invention is directed to providing an inexpensive, yet effective, simulation for measuring the sound level of the muffler contribution to the total sound created by a truck during a drive-by. The simulation method includes disconnecting a drive shaft of the drive mechanism of the truck and installing a dynamometer. When the throttle of the engine is increased, the dynamometer applies a load so that the acceleration rate of the drive mechanism compares similarly to the acceleration rates of a truck during an actual drive-by test in accordance with CFR 40, part 202. Sound barriers are placed around sounds sources other than the muffler of the truck. Microphones are used to sense the sound during the test for recording by strip-chart recorders.

Method and apparatus for sound testing mufflers

The present invention is directed to muffler apparatus and a method for making same. The apparatus includes inlet and outlet tubes with a plurality of baffles extending from the inlet and outlet tubes to a housing. The outlet tube has a constricted portion near its inlet end formed with creases and lobes and a flare at the end. Such constriction increases the housing to outlet tube area ratio of the muffler which results in advantageous attenuation characteristics. The process for making the muffler is simpler than known methods since the outlet tube is formed and baffles pressed onto it in a single step.

Muffler apparatus and method for making same

The specification discloses an improved clamp (20) for securing overlapping telescoped ends of adjacent tubes in an exhaust system, or the like, to form a substantially leakproof joint. The clamp (20) includes a circular band (26) and a bolt (32) having a curved end (34) secured thereto over a predetermined circumferential distance adjacent one end of the band, and a straight threaded end extending through an extension (40) secured adjacent to the opposite end of the band. A nut (44) is provided on the straight bolt end (38) for tightening against the extension (40) to draw the ends (28 and 30) of the band (26) together in near abutting relationship to engage the lap joint over a substantially continuous circumferential area in a second embodiment (60). The extension (62) can bridge the gap to serve as a guide for the other end of the band, or it can be an integral portion (72 and 74) of the band in a third embodiment (70).

Growing community of inventors

Apple Valley, MN, United States of America

Timothy A Bethke