Instrument for tissue sampling

A tissue sampling instrument for use with a two-part needle assembly having an outer, first needle cannula within which an inner second needle stylet is axially translated, said instrument comprising:

• a) a first carriage structure affixed to and for carrying and displacing said inner stylet through said outer cannula;
• b) second carriage structure affixed to and for carrying and displacing said outer cannula relative to said inner stylet;
• and
• c) drive means for separately and sequentially engaging and displacing said first carriage structure followed by engaging and displacing said second carriage structure in order to produce sequential motions of the stylet and cannula and capture of a tissue sample therebetween, wherein said drive means comprises a single spring member for propelling said displacements of both said first and second carriage structures.

A tissue sampling instrument for use with a two-part needle assembly having an outer, first needle cannula within which an inner second needle stylet is axially translated, said instrument comprising:

• a) a first carriage structure affixed to and for carrying and displacing said inner stylet through said outer cannula;
• b) second carriage structure affixed to and for carrying and displacing said outer cannula relative to said inner stylet;
• and
• c) drive means for separately and sequentially engaging and displacing said first carriage structure followed by engaging and displacing said second carriage structure in order to produce sequential motions of the stylet and cannula and capture of a tissue sample therebetween, wherein said drive means comprises:
• a single spring member;
• a drive assembly movable between a first and second position propelled by said spring member, and including a trailer member adapted when said drive assembly is in said first position to engage said first, stylet carriage structure such that the motion of said drive assembly from said first position toward said second position advances said first stylet carriage structure;
• cam means for disengaging said trailer member from said first stylet carriage structure at an intermediate point in said movement of said drive assembly thereby terminating the advance movement of said first stylet carriage structure;
• and means on said drive assembly for engaging said second cannula carriage structure at an intermediate point in said movement of said drive assembly toward said second position, and for propelling said advancing movement of said second cannula carriage structure after said termination of the advancing movement of said first, stylet carriage structure to cause said tissue sample capture between said stylet and cannula.

A tissue sampling instrument for use with a two-part needle assembly having an outer, first needle cannula within which an inner second needle stylet is axially translated, said instrument comprising:

• a) a first carriage structure affixed to and for carrying and displacing said inner stylet through said outer cannula;
• b) second carriage structure affixed to and for carrying and displacing said outer cannula relative to said inner stylet;
• and
• c) drive means for separately and sequentially engaging and displacing said first carriage structure followed by engaging and displacing said second carriage structure in order to produce sequential motions of the stylet and cannula and capture of a tissue sample therebetween, further comprising counting and disabling means for registering the number of successive tissue sampling operations of said instrument and for disabling said instrument after a selected number of said operations have been completed.