Frictionless positioning grommet for engine gasket

Claim 1

In a gasket having a plurality of apertures, at least two of which are adapted to accommodate passage of mechanical fasteners, said gasket being disposed for securement between two separate but communicating parts of an engine, said parts containing mating bores for accommodating passage of said mechanical fasteners; an improvement comprising one of said engine parts having a counterbore disposed concentrically in each of two of said engine fastener bores, each counterbore defining an axis, and a plurality of grommets fixed to said gasket for locating said gasket relative to said one engine part, one grommet disposed within each one of said counterbores, each counterbore and associated grommet sized for frictionless, interference-free radial clearance, wherein each grommet defines a generally cylindrical body having an axis coincident with said axis of its associated counterbore, a first end of said cylindrical body comprising a first plurality of radially extending, symmetrically spaced flanges circumferentially distributed about said axis, an intermediate portion of said cylindrical body comprising a second plurality of radially extending, symmetrically spaced flanges, also circumferentially distributed about said axis, said first and second pluralities of flanges being axially spaced apart and with individual flanges of said first and second respective pluralities being circumferentially offset from one another, wherein said axially spaced first and second pluralities are compressed axially toward each other to secure each said grommet to said gasket, and wherein said cylindrical body of each grommet comprises a plurality of integral detents, each detect symmetrically and radially aligned with one flange of said second plurality.