Hand tool e.g. screw driver - has planetary reduction gearing between handle and blade augmenting hand torque

摘要

The reduction gear cage cheek plate 8 houses a jawed mandrel 16 for bit 26 location and some planets have elastic end floats assisting unjamming. A shaft stub projects from a handle to form a gear wheel 3 about which enmeshing planet gears 4 rotate, these latter being spindled to and meshing externally with a shallow cylinder cage 6, 7, 8: the outer end of which 8 receives blades 26 etc, and which is externally gripped by the free hand to provide an anti-coupling effect.