Top using crank arm refraction

The present invention relates to a saw using a refractory motion of a crank arm， wherein the saw using a refractory motion of a crank arm is linked to a crank arm that revolves around the solar axis， and a multi-crank that is reciprocally rotated by being linked to a crank arm As the position of the multi-crank pin is freely corrected by the refracting motion according to the mutual reverse rotation of the arm， the linear reciprocating force required for cutting and transferring the straight rod is accurately transmitted， and especially the crank arm is 180° without being affected by the rotational angle of the sun axis The multi-crank arm is aligned in a straight line at each point of the isometric rotation， and the cutting stroke distance of the straight rod is extended， and the solar shaft rotational force is increased and decreased freely， so that the cutting torque can be easily adjusted by adjusting the cutting torque. It consists of a main configuration including a crank arm 20， a planetary gear 30， a multi-crank arm 40， and a straight rod portion 50.