Abstract: A method is disclosed for bending panels which are provided with reinforcing stiffening ribs. The bending is caused by upsetting or elongating the ribs. Apparatus for carrying out the method also is disclosed and includes means which engage the ribs at points spaced a predetermined distance from the panel skin. The invention is particularly applicable to the shaping of aircraft fuselage skin sections.

Abstract: This invention relates to an improvement in a hand drill with a pneumatically-hydraulically controlled advance and including a housing, a drilling drive unit adapted to be powered by compressed air and being displaceably guided in said housing by a piston and cylinder, and further including hydraulic lines, and control valves, the improvement comprising a rotatable support sleeve means secured to said housing and adapted to rest on the surface of a workpiece and surround a drill bit, said piston being a double-faced hollow advance piston means mounted in said cylinder so as to divide said cylinder into two chambers, one chamber together with one face of the advance piston means being adapted to be acted on by the compressed air, and the other chamber being adapted to be filled with hydraulic fluid and pressure-loaded by the other face of the advance piston means, said latter chamber communicating through hydraulic line means and a throttling back-pressure valve means with a cylinder means having a compensatin