Locking mechanism for a medical device

A medical device assembly, comprising:

• an elongate member;
• a handle assembly coupled to the elongate member, the handle assembly including a housing having a locking mechanism, the locking mechanism comprising:
• a flexible tubular member positioned in the housing, a portion of the elongate member extending through the flexible tubular member;
• an actuator pivotably attached to the housing about a pivot axis, the actuator being pivotable between a first position and a second position, wherein the actuator includes a cam portion with an eccentric surface having a variable distance from the pivot axis;
• and
• a push member positioned between the flexible tubular member and the actuator, wherein a first surface of the push member is configured to contact the eccentric surface of the cam portion, and a second surface of the push member is configured to contact the flexible tubular member;
• wherein the push member does not compress the flexible tubular member against the elongate member when the actuator is in the first position, and the push member deforms an outer surface of the flexible tubular member inward to compress the flexible tubular member against the elongate member when the actuator is in the second position.