Curvature control mechanism in endoscopes

摘要

A curvature control mechanism in an endoscope is disclosed. The endoscope is of the type which has a manipulator unit to which a flexible tubular member is connected and whose front end region constitutes a bendable portion. A knob member is rotatably mounted on the manipulator unit and control wires extend from the manipulator unit through the flexible member to the bendable portion so the latter can be bent by the wires in a selectively controlled manner through rotation of the knob. The curvature control mechanism includes a double cylinder type drum device including two drums fixedly mounted on a rotary shaft coupled to the knob. A pair of elongate resilient strips are wound around respective drums in mutually opposite directions and one end of each of the resilient strips is coupled to a respective control wire such that rotation of the drums in one direction causes a take-up of one of the elongate strips on its respective drum and a tension-relief in the other of the resilient strips in the form of a diametric expansion thereof, such expansion preventing an excessive slackness in the control wire to which that resilient strip is coupled while maintaining at least some tension in that control wire.