So far hand-operated electric devices with high internal force have been produced with multi-level spur wheel or multi-level planetary gears. These gears are very elaborate. Eccentric gears are a new development for hand-operated electric devices as there are nibblers, plate shears, welding edge shears and so on.

There are two types with a parallel crank and Oldham coupler, with two types of construction each, with a hollow wheel or with a rotating hollow wheel. The gears are designed in a way that a very high reduction and a calm, low vibrating run is achieved. This is achieved by statically and dynamically affecting imbalance-counterweights!