This court decision isn't particularly interesting if you're not a patent type ("In order to prevent the flexible elastic ring from being dislodged from its seating by the intense compression of the parts, the '657 patent discloses the use of an annular extension 33 on the cutting ring 14, and a corresponding annular extension 34 on the shutter mechanism 3, to hold the flexible elastic ring in place.") . . . but you gotta love the name of the case:  Schwing GmbH v. Putzmeister AG, ___ F.3d ___, 2002 WL 31109922, 2002 U.S. App. LEXIS 20205 (Fed. Cir. Sept. 24, 2002).