Insertion Lever Mechanism That Restricts Shaft Rotation
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Solution Overview
Problem
Conventional insertion instruments with joystick-type bending operation levers suffer from operational degradation due to rotation about a shaft, leading to a complex structure and increased number of components.
Innovation Solution
A bending operation mechanism that supports the bending operation lever through two orthogonal rotation shafts, incorporating a rotor with a concave surface and a restriction member to restrict rotation while allowing inclination in all directions, using a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a joystick-type bending operation lever is used to enable bending in all directions, then the bending operation capability is improved, but the structure becomes complex and the number of components increases
Solution Approach 1:
The bending operation mechanism is segmented into two independent functional components: a ball joint mechanism that enables multi-directional inclination (up, down, left, right) and a separate rotation restriction mechanism that prevents unwanted rotation about the shaft. This segmentation allows each component to perform its specific function with a simple structure, avoiding the need for a complex integrated mechanism.
Solution Approach 2:
A rotation restriction mechanism acts as an intermediary element between the ball joint and the bending operation lever. This intermediary component selectively restricts rotation about the shaft while permitting inclination movements, thereby enabling accurate bending operations without requiring a complex multi-constraint mechanism.
2Adaptability or versatility
If a ball joint is used to allow tilting in all directions, then the bending operation flexibility is improved, but rotation about the shaft cannot be restricted
Solution Approach 1:
The mechanism dynamically controls the degrees of freedom of the bending operation lever. The ball joint provides dynamic freedom for inclination in all directions, while the rotation restriction mechanism dynamically constrains rotation about the shaft. This dynamic control allows the system to adapt its constraints based on the required operation, maintaining both flexibility and accuracy.
3Device complexity
If two rotation shafts are used to support the lever, then the structure becomes simpler, but rotation about the shaft cannot be restricted
Solution Approach 1:
The rotation restriction mechanism introduces asymmetric constraints to the otherwise symmetric ball joint structure. While the ball joint allows symmetric inclination movements in all directions, the rotation restriction mechanism applies an asymmetric constraint that specifically prevents rotation about the shaft while permitting other movements. This asymmetric design enables operational accuracy without significantly increasing structural complexity.
Data Source
AI summary
An insertion instrument comprises an insertion portion including a bending portion provided at a distal end side of the insertion portion, a first wire provided in the insertion portion, and an operation portion provided at a proximal end side of the insertion portion. The operation portion includes a bending operation unit. The bending operation unit includes a lever having a central shaft defining a central axis, a rotor coupled to the lever, a wire attachment surface to which the first wire is attached. An inner surface of the operation portion includes a receiver body and a restriction body. The receiver body supports the rotor for rotation about the central axis and for movement of the lever from a neutral position to an inclined position, where, in the inclined position, the central shaft is inclined relative to the central shaft in the neutral position. Movement of the lever from the neutral position to the inclined position pulls the first wire to bend the bending portion. The restriction surface restricts a portion of the rotation of the rotor about the central axis.