Patent ID: 8911310

Claim:
An arrowhead having expanding blades controlled by a gear mechanism, comprising: a penetrating tip including a sharpened leading end and a screw thread formed on an inner peripheral surface thereof; a main body adapted to allow a lower end of the penetrating tip to be inserted therein, the main body including a body portion having a hollow portion therein and openings on upper and lower end sides thereof, a plurality of expanding blade coupling pieces formed on an outer surface of the body portion, and a plurality of expanding blade receiving grooves respectively formed on a surface of each of the plurality of expanding blade coupling pieces; a plurality of expanding blades respectively hingedly and rotatably coupled to each of the expanding blade coupling pieces, the plurality of expanding blades each including a blade formed on one side end thereof and a pinion gear portion formed on a lower end thereof; a shaft including a body portion, a front-end threaded portion formed on an upper end of the body portion to be coupled to the screw thread of the penetrating tip, a rear-end threaded portion formed on a lower end of the body portion to be coupled to an arrow shaft, a rack gear portion provided on an outer peripheral surface of the body portion to be engaged with the pinion gear portion, and a stopper formed to protrude from the outer peripheral surface below the rack gear portion; and a spring mounted on the shaft; wherein a relative movement between the rack gear portion and the pinion gear portion causes a retraction or expansion of the expanding blades.