US Patent 9272347 Drive mechanism for a reciprocating tool

In one embodiment, a reciprocating tool includes an elongated spindle configured to reciprocate along its lengthwise axis, a wobble drive mechanism operably connected to the elongated spindle, an elongated rocker assembly having an upper end portion operably connected to the spindle, a lower end portion, and a pivot located between the upper and lower end portions, and a counterweight operably connected to the lower end portion, such that as the elongated spindle reciprocates along its lengthwise axis, the counterweight is driven by the elongated rocker assembly to reciprocate along the axis.