| 摘要 |
<p>A method of forming a sector for a nacelle lip skin from a sheet metal blank comprising the steps of: providing an arcuate or annular punch (7) or mandrel having an inner surface, an outer surface and a leading edge, said punch (7) substantially corresponding in shape to an inner surface of at least a sector of the nacelle lip skin, placing the blank (13) against the outer surface of the punch (7) and clamping a trailing edge of the blank (13) in a clamping means (11,12) to hold the blank (13) against the outer surface of the punch (7), said clamping means (11,12) gripping said trailing edge of the blank without slippage; gripping a leading edge of the blank (13), opposite said trailing edge, in a gripping means (8,9), at a location axially spaced from said punch (7) adjacent and in front of the leading edge of the punch (7), said gripping means (8,9) gripping said blank (13) with sufficient force to permit the blank (13) to flow therethrough in a controlled manner without tearing or wrinkling; displacing the gripping means (8,9) in a first direction, substantially radially with respect to the punch (7), towards the central axis of the punch (7) while drawing the blank through the gripping means (8,9); displacing the gripping means (8,9) in a second direction, substantially axially with respect to the punch (7), towards and past the leading edge of the punch (7), to draw the blank (13) over the leading edge of the punch (7) while drawing the blank (13) through the gripping means (8,9).</p> |
