Asymmetric shaft seal

An integral seal system, comprising:

• a body that defines a central opening;
• an asymmetric seal extending into the central opening and including a diaphragm and an annular flange that extends between the body and the diaphragm, wherein the diaphragm has a cross-sectional thickness larger than a cross-sectional thickness of the annular flange;
• and
• a duckbill seal axially spaced and separated from the asymmetric seal and defining one or more parting lines that separate opposing seal flaps,
• wherein the diaphragm complements insertion and extraction drag forces generated by the duckbill seal against a surgical tool shaft extended therethrough such that total insertion and extraction drag forces generated by the integral seal system are equalized,
• wherein, when in a relaxed state, the diaphragm projects from the annular flange in a proximal direction away from the duckbill seal, and
• wherein the asymmetric seal and the duckbill seal are formed together as a single structure.

A method, comprising:

• penetrating an integral seal system with a surgical tool shaft, the integral seal system including:
• a body that defines a central opening;
• an asymmetric seal extending into the central opening and including a diaphragm and an annular flange that extends between the body and the diaphragm, wherein the diaphragm has a cross-sectional thickness larger than a cross-sectional thickness of the annular flange;
• and
• a duckbill seal axially spaced from the asymmetric seal and defining one or more parting lines that separate opposing seal flaps, wherein, when in a relaxed state, the diaphragm projects from the annular flange in a proximal direction away from the duckbill seal, and wherein the asymmetric seal and the duckbill seal are formed together as a single structure;
• generating a first insertion drag force as the diaphragm engages the surgical tool shaft;
• generating a second insertion drag force as the duckbill seal engages the surgical tool shaft;
• and
• extracting the surgical tool shaft from the central passageway and thereby generating a first extraction drag force with the diaphragm and a section extraction drag force with the duckbill seal,
• wherein the first insertion drag force complements the second insertion drag force and the first extraction drag force complements the second extraction drag force such that total insertion and extraction drag forces generated by the integral seal system are equalized.