Endoscope with sheath retaining device

An endoscope assembly for performing an endoscopic procedure, comprising:

• a sheath having a distal end portion movable between a radially expanded position and a contracted position, the distal end portion of the sheath being biased toward the contracted position, the sheath having a working channel extending therethrough;
• and
• an endoscope having a handle, an insertion tube extending away from the handle and terminating at a distal end portion, and a sheath retaining member connected to the distal end portion of the insertion tube, the distal end portion of the insertion tube having a non-circular cross-sectional area and having an outer surface defined by first and second surface portions, the first surface portion being semi-cylindrical, the sheath retaining member having a pair of spaced-apart retaining tabs extending away from the distal end portion of the insertion tube and defining a working channel receiving area therebetween and adjacent the second surface portion, the retaining tabs being sized so the distal end portion of the sheath is stretched over the retaining tabs when the distal end portion of the insertion tube is adjacent the distal end portion of the sheath and when the distal end portion of the sheath is in the contracted position, the retaining tabs having engaging surfaces that engage the sheath when the sheath is in the contracted position and that prevent the distal end portion of the sheath of the insertion tube from moving relative to the distal end portion of the insertion tube.

A method of securing a sheath having a working channel extending therethrough on an insertion tube of an endoscope, the sheath being sized to receive the insertion tube therein, the insertion tube having a distal end portion with a pair of spaced-apart protruding sheath retaining tabs thereon, the sheath retaining tabs defining a working channel receiving area therebetween, comprising the steps of:

• radially expanding the sheath to an expanded position;
• inserting the insertion tube into the sheath when in the expanded position and positioning a portion of the working channel in the working channel receiving area and positioning the distal end portion of the insertion tube adjacent a distal end portion of the sheath;
• moving the sheath from the expanded position to a contracted position after the distal end portion of the insertion tube is adjacent to the distal end portion of the sheath;
• and
• stretching a portion of the sheath over the sheath retaining tabs with the portion of the sheath tightly engaging the sheath retaining tabs, the sheath retaining tabs retaining the distal end portion of the sheath adjacent the distal end portion of the insertion tube and preventing axial movement of the distal end portion of the sheath relative to the distal end portion of the insertion tube.