Abstract: Each fan-blade carries a bevel-pinion in mesh with two bevel ring-gears which are driven in rotation in opposite directions by means of two coaxial cylindrical tubular members. Carriages are mounted for axial motion within the space formed between the two tubular members; balls are fitted in helical grooves formed at opposite angles of slope in the internal and external cylindrical faces of the carriages and in corresponding helical grooves formed in the adjacent faces of the tubular members so as to form a ball-race. The moving member of at least one axial hydraulic jack constituting a motor is coupled to the carriages and the stationary member is coupled to the fan-shaft.

Abstract: An improved broaching machine comprises a device for accumulating at least part of the kinetic energy stored during the travel of the tool-carrier slide-block within the assembly constituted by the slide-block, the rotor of the electric motor and the transmission system as well as means for transferring the energy from the slide-block to the accumulation device and conversely.