Patent ID: 8597204

Claim:
A biopsy device, comprising: a housing; a coring cannula coupled to the housing and having a longitudinal axis and a shaft centered on the axis; a stylet having a tip containing at least one blade, a central passage centered along the same axis as the shaft of the coring cannula, and a guide portion extending past the opening of the central passage; a motor assembly coupled to the coring cannula for controllably rotating the cannula; a variable speed circuit electrically coupled to the motor assembly; a forward/reverse switch electrically coupled to the variable speed circuit for controlling the direction of movement of the cannula; a speed control trigger electrically coupled to the variable speed circuit, the variable speed circuit for responsively controlling the speed and rotation of the cannula as a function of the forward/reverse switch and actuation of the speed control trigger; and, a needle assembly, the needle assembly including: a localization needle having first and second ends and an internal bore; a handle having first and second ends and an internal bore, the first end of the needle fixed to the second end of the handle, the internal bore of the needle and the internal bore of the handle forming an assembly bore therethrough; a guide element having a guide rod and a locking member, the guide element having first and second ends and being removably contained within the assembly bore and also being sized to the central passage of the stylet, the locking member being fixed to an end of the guide rod; and, a plunger, having a pushrod and an actuation element coupled to the pushrod, the plunger being movable from a first state to a second state, one end of the pushrod acting on the first end of the guide rod, forcing the locking member out of the needle as the pushrod is moved from the first state to the second state wherein the guide element is configured to, after being removed from the assembly bore, rest along the guide portion of the stylet, enter the central passage of the stylet; and wherein the central passage of the stylet is configured to receive the guide element along the longitudinal axis.