| 主权项 |
1. A biopsy device, comprising:
a first cannula having a first side wall defining a first lumen, said first cannula having a first proximal end and a first distal end, said first cannula having a first aperture extending through said first side wall to said first lumen proximal to said first distal end, said first cannula having a longitudinal axis; a second cannula having a second side wall defining a second lumen, said second cannula having a second proximal end and a second distal end, said second cannula having a second aperture extending through said second side wall to said second lumen proximal to said second distal end, said second cannula being disposed co-axially with said first cannula, at least one of said first aperture and said second aperture having a cutting edge; and a driver unit having a ratchet drive mechanism operatively coupled to said first cannula and said second cannula, said ratchet drive mechanism including:
a first gear fixedly attached to said first cannula;a second gear fixedly attached to said second cannula;a torsion spring located between said first gear and said second gear, said torsion spring having a first end portion and a second end portion, said first end portion being connected to said first gear and said second end portion being connected to said second gear, said ratchet drive mechanism being configured such that said torsion spring stores energy which when released drivably rotates one of said first gear and said second gear relative to the other of said first gear and said second gear,wherein said first cannula is an outer cannula having a needle tip located at said first distal end and second cannula is an inner cannula positioned in said first lumen of said outer cannula, said ratchet drive mechanism being configured to wind said torsion spring to store said energy during a cocking operation and configured to release said torsion spring during a firing operation to drivably rotate said first gear to rotate said outer cannula relative to said inner cannula;an outer cannula advance actuator configured to rotate said first gear in discrete rotational increments in a first rotational direction;an inner cannula advance actuator configured to rotate said second gear in discrete rotational increments in a second rotational direction opposite to said first rotational direction;an outer cannula slide actuator having a first cantilever pawl, said outer cannula slide actuator being configured to selectively engage said first gear, wherein when said first cantilever pawl is engaged with said first gear, said first gear and said outer cannula are prevented from rotation in said second rotational direction; andan inner cannula slide actuator having a second cantilever pawl, said inner cannula slide actuator being configured to selectively engage said second gear, wherein when said second cantilever pawl is engaged with said second gear, said second gear and said inner cannula are prevented from rotation in said first rotational direction. |
