Tissue gripping and cutting assembly for surgical instrument

Claim 1

In a surgical instrument for use in surgical procedures involving tissue cutting, a sheathed blade assembly comprising an elongate sheath and a plurality of elongate surgical blades longitudinally received within said sheath for reciprocal guided movement therein, said blades comprises a cutting blade and a gripping blade, said gripping blade including a leading end with a working head having gripping means thereon for gripping engagement with tissue, said cutting blade including a leading end with a working head having cutting means thereon for the cutting of tissue engaged by said gripping means, said sheath having forward and rear end portions, said forward end portion terminating in an open forward blade-passing end, each said blade working head being completely retractable into said sheath, positioning means external of said sheath for reciprocation of said blades relative to said sheath and selective extension and retraction of the working head of each blade relative to the open forward end of the sheath for a selective exposure of the working heads of said blades beyond said forward end, means for selectively retaining said gripping blade with the working head thereof exposed beyond the forward end of the sheath independently of said cutting blade, said blades including following end portions extending rearward of said sheath, said blade following end portions, upon reciprocation of said blades, being selectively extensible forwardly into the sheath and retractable rearwardly from the sheath, said means for retaining said gripping blade with the working head thereof exposed being defined by a laterally enlargement of the following end portion of said gripping blade, said sheath having a generally constant internal transverse dimension along at least the rear end portion thereof, said lateral enlargement defining a transverse blade dimension greater than said internal transverse dimension of the rear end portion of the sheath whereby extension of the following end portion of the gripping blade into the sheath will effect a releasable frictional fixing of said gripping blade within said sheath, the lateral enlargement of the following end portion of the gripping blade being defined by a pair of rearwardly extending elongate sections, at least one of said sections diverging laterally outward from the other section and incorporating a degree of resilient flexiblity for a selective lateral flexing of said one section toward the other section upon extension of said sections into the sheath, means limiting the forward extension of the following end portion of the gripping blade in to the sheath, and blade control means engaged between said cutting blade and said gripping blade for a selective reciprocation of said gripping blade in response to reciprocation of said cutting blade, said positioning means external of said sheath for reciprocation of said blades being engaged solely with said cutting blade.