A broadhead arrowhead having fully retractable blades wherein a plunger of the tip of the arrowhead causes the blades to shear a shear pin and deploy when the arrowhead strikes a target. In an alternative embodiment, the blades are retained in the arrowhead by a friction fit that is overcome to deploy the blades when the arrowhead strikes a target.
1. An arrowhead comprising: (a) a cylindrical ferrule; (b) a tip; (c) a first blade; (d) a second blade; (e) a hinge pin; and (f) a shear pin, the ferrule having a longitudinal axis, the ferrule having a passageway thereinto along the longitudinal axis of the ferrule, the tip having a shank dimensioned to pass into the passageway, the ferrule having a first elongated aperture into said passageway on one side of the ferrule into which the first blade is positioned within the ferrule, the ferrule having a second elongated aperture into said passageway on the other side of the ferrule into which the second blade is positioned within the ferrule, the first blade having a first aperture near one end and a second aperture near the other end, the second blade having a first aperture near one end and a second aperture near the other end, the hinge pin positioned through the first aperture of the first and second blades, the hinge pin positioned near the shank of the tip, the ferrule having a bore therethrough transverse to the longitudinal axis of the ferrule, the shear pin positioned through said bore and through the second apertures of the first and second blades so that when the arrowhead strikes a game animal the shank of the tip pushes the hinge pin and blades to move in a direction along the longitudinal axis of the ferrule away from the tip to shear the shear pin so that the blades swing out from the ferrule on the hinge pin.
2. The arrowhead of claim 1 , wherein the tip terminates at the point of a pyramid with the edges of the faces of the pyramid being notched.
3. The arrowhead of claim 2 , wherein the notches are cylindrical in shape and transverse to the longitudinal axis of the ferrule.
4. The arrowhead of claim 2 , wherein the pyramid has three faces and wherein the notches are cylindrical in shape and transverse to the longitudinal axis of the ferrule.
5. The arrowhead of claim 4 , wherein the shear pin is made of an elastomer.
6. The arrowhead of claim 1 , wherein the shear pin is made of an elastomer.
7. A kit of parts packaged for retail sale, comprising: (a) the arrowhead of claim 6 ; and (b) a plurality of shear pins each being colored coded to correspond to the durometer value of the shear pin.
8. The kit of parts of claim 7 , wherein the tip of the arrowhead terminates at the point of a pyramid with the edges of the faces of the pyramid being notched.
9. The kit of parts of claim 7 , wherein the pyramid has three faces and wherein the notches are cylindrical in shape and transverse to the longitudinal axis of the ferrule.