Patent ID: 7325793

Claim:
A rolling-lobe air spring comprising: a rolling-lobe resilient member having a bead at an end thereof; a flanged plate including a rim, a planar base and a convex arcuate portion connecting said rim to said base; said flanged plate having a convex outer surface at said convex arcuate portion; said flanged plate having an annular continuous concave holding recess formed therein at said convex outer surface; said holding recess having a depth less than the thickness of said flanged plate and being arranged in a complete revolution about the entire periphery of said flanged plate; said flanged plate having a corrosion protective layer applied in advance of a flanging operation with said corrosion protective layer being applied so as to cover said flanged plate including said holding recess; and, said flanged plate being devoid of material flow between said rim and said planar base when said flanged plate is flanged to said bead of said resilient member when an upper flanging tool acts on said flanged plate by pressing down thereagainst with said holding recess being in contact engagement with a convex holding bead of the upper flanging work tool.