Variable offset crankshaft

A tool having a motor and a drive mechanism, the tool comprising:

• a crankshaft including:
• a crankshaft base having opposing first and second end portions, wherein the first end portion is operably coupled to the drive mechanism;
• and
• a crank pin slider with a crank pin, wherein the crank pin slider is slidably coupled to the second end portion of the crankshaft base;
• and
• an output mechanism operably coupled to the crank pin.

A crankshaft for a tool with a drive mechanism and an output mechanism, the crankshaft comprising:

• a crankshaft base having opposing first and second end portions, wherein the first end portion includes gear teeth adapted to operably couple to the drive mechanism, and the second end portion includes a projection with a blind-hole and a first through-hole;
• a crank pin slider having a channel that slidably receives the projection, a crank pin that is adapted to operably couple to the output mechanism, and a second through-hole;
• a fastening member disposed in the first and second through-holes, wherein the second through-hole has an elongated shape that is adapted to allow the crank pin slider to move relative to the crankshaft base and the fastening member;
• and
• a bias member disposed in the blind-hole and adapted to apply a bias force to the crank pin slider and bias the crank pin slider to a first offset position, wherein inertial forces on the crank pin slider overcome the bias force as a rotational speed of the crankshaft base increases and cause the crank pin slider to move relative to the crankshaft base towards a second offset position.