Fan blade reinforcement plate

Claim 1

In a fan having a hub, an arm extending radially from said hub, a blade for said arm, and fastening means securing said blade to said arm, said fastening means including a rivet, said blade and said arm having aligned apertures receiving said rivet, and a reinforcing plate secured to said blade by said rivet when the blade is attached to the arm, said reinforcing plate having a free contour before installation of the plate on said blade different from the contour of the portion of the blade engaged by said plate when the plate and the blade are attached to the arm so that the plate is preloaded when it is secured to said blade, said rivet securing the plate to said blade and forcing a portion of the plate to assume the contour of said portion of the blade, said portion of the blade being depressed and cooperating with the rest of the blade to define a rim, said plate having a depression and a raised flange around at least a portion of the depression, said flange and said depression defining the free contour of the plate, said flange extending over the rim to cover the latter when the plate is installed on the blade, said rim and said depressed portion defining the free contour of said portion of the blade engaged by said plate, said rivet holding the depression on the plate against the depressed portion of the blade to force said raised flange of the plate against the rim of the blade, whereby bending forces are transferred through said plate away from said apertures.