Appeal No. 2002-2148 Page 7
Application No. 09/627,143
preferably both of the pressure side 46 and the suction side 48 have a laser shock
peened surface 54 and a pre-stressed region 56 having deep compressive residual
stresses imparted by laser shock peening (LSP) extending into the airfoil 34 from the
laser shock peened surface in the tip section 50 along the blade tip 38 as seen
in Figure 2. Preferably, the pre-stressed regions 56 are coextensive with the blade tip
38 in the chordwise direction to the full extent of width W1 and are deep enough
into the airfoil 34 to coalesce for at least a part of the width W1. The laser beam shock
induced deep compressive residual stresses in the compressive pre-stressed regions
56 are generally about 50-150 KPSI (Kilo Pounds per Square Inch) extending from the
laser shock surfaces 54 to a depth of about 20-50 mils into laser shock induced
compressive residually pre-stressed regions 56.
The appellants argue (brief, pp. 5-7) that the subject matter of claims 1, 2 and 8
is not met by Mannava since Mannava does not teach a band under a compressive
stress greater than the body through the entire cross section of the band. The
examiner responded to this argument (answer, p. 4) by asserting that the claims do not
recite the entire cross section of the band being under a compressive stress greater
than the body. In the examiner's view, the claims recite only that a compressive stress
greater than the body is in the band. The appellants strongly disagreed (reply brief, pp.
1-2) with the examiner's interpretation of the claimed subject matter. Specifically, the
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