Articulation Cam Profile for Lower-Torque Endoscopic Deflection
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Solution Overview
Problem
Conventional endoscopic systems experience increased user tension and decreased responsiveness due to the design of articulation mechanisms, leading to hand fatigue and reduced articulation responsiveness as the articulation mechanism is rotated.
Innovation Solution
A medical device with a cam mechanism that includes sections with varying radii of curvature for the actuation wire path, allowing for controlled deflection of the shaft with reduced torque and improved responsiveness by alternating the path of the actuation wire based on rotation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional articulation mechanism with a cam is used to control shaft deflection, then the shaft can be deflected to access target sites, but the tension felt by the user increases as the articulation mechanism is rotated, causing hand fatigue
Solution Approach 1:
The cam profile is designed with varying radial distances - a first section with a first radial distance and a second section with a second radial distance that is less than the first radial distance. This parameter change in the cam geometry allows the actuation wire to wrap around different sections during rotation, reducing the leverage and thereby reducing the tension felt by the user on the actuation mechanism.
2Shape
If the articulation mechanism is rotated to achieve maximum bend, then the shaft deflection angle increases, but the responsiveness of the articulation joint decreases
Solution Approach 1:
The cam profile incorporates sections with different radial distances that correspond to different phases of articulation. The first section with greater radial distance provides mechanical advantage for initiating deflection, while the second section with lesser radial distance maintains responsiveness during larger deflection angles. This parameter variation in the cam geometry optimizes the transmission of user input to shaft deflection across the full range of motion.
Data Source
AI summary
A medical device includes a handle including an actuating device, a shaft extending from the handle and having a longitudinal axis, a cam rotatably connected to the handle, wherein the cam includes a first section and a second section, and wherein a distance between a radially outer surface of the first section and a center of the cam is different from a distance between a radially outer surface of the second section and the center of the cam; and an actuation wire extending from the cam to a distal end of the shaft. Rotation of the actuating device rotates the cam, causing the actuating wire to wrap around the first section and the second section to deflect the distal end of the shaft.