US Patent 10415940 Over center expanding arrowhead

Improvements in an expanding arrowhead where the initial launching thrust of launching an arrow keeps the blades retracted within the head of the arrow. The blades remain retracted because the center of mass of the blades is on the opposite side of the rotational pivoting axis of the blades. When the blades contact a target a wing tip on the blades pull the blades open. There are two or three blades that can be retained within the head of the arrow. The blades are loosely retained in a retracted orientation for transportation. The retention is sufficient to overcome the forces or gravity yet release with slight force on then ends of the blades. When the arrow is pulled through the wound track the blades fold back into the head or body.