Patent attributes
A trocar having a cutting shaft with a cutting surface at a distal end. The cutting shaft moves longitudinally with respect to an obturator such that in one position the cutting surface is in an exposed position suitable for application of a piercing force. Upon interruption of the piercing force to the cutting surface, the cutting surface moves longitudinally with respect to the obturator such that the cutting surface is in a retracted position within the obturator. The trocar may include a first spring urging the cutting surface to an exposed position and a second spring urging the cutting surface to a retracted position. The second spring has a slightly stronger biasing force than the first spring to bias the cutting surface to the retracted position.
