Shaft Stop Mechanism for Constrained Rotational Range
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Solution Overview
Problem
There is a need for constraint mechanisms in tools like surgical instruments that do not occupy excessive space, provide reliable movement restriction of rotational ranges, and prevent unintentional activation, while maintaining accurate encoding of position.
Innovation Solution
The implementation of a stop mechanism that transitions between states to constrain rotational motion of a shaft within a predefined range, using a rotary device with a protrusion and notch system that interacts with the shaft to limit rotation, allowing for reliable constraint without a circumferentially surrounding structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stop mechanism is added to constrain rotational motion of the shaft, then the reliability of movement restriction is improved, but the device complexity increases
Solution Approach 1:
The stop mechanism is nested within the existing shaft structure. The stop mechanism includes a stop element that is positioned within the shaft, and the shaft itself serves as part of the constraint structure. This nesting approach allows the stop mechanism to be integrated into the existing tool architecture without adding excessive external components, thereby improving movement restriction reliability while minimizing the increase in overall device complexity.
2Reliability
If a stop mechanism is added to constrain rotational motion, then the reliability of movement restriction is improved, but the volume of the tool increases
Solution Approach 1:
The stop mechanism is designed to occupy minimal space by implementing constraint functionality at the local level where it is most effective. The stop element is positioned at a specific location on the shaft where it can effectively constrain rotational motion without requiring a circumferentially surrounding structure. This localized approach ensures that the tool's overall volume is not significantly increased while still achieving reliable movement restriction.
3Measurement precision
If the shaft is constrained to a predefined range of rotational motion, then the accuracy of position encoding is improved, but the ease of operation decreases
Solution Approach 1:
The stop mechanism is designed to dynamically transition between different constraint states. The stop element can engage with the shaft to constrain rotational motion within a predefined range, and can disengage to allow free rotation when not needed. This dynamic behavior enables the system to maintain accurate position encoding when constraint is required, while preserving operational flexibility when the full range of motion is needed, thus resolving the contradiction between measurement precision and ease of operation.
Data Source
AI summary
A tool includes a transmission mechanism, a shaft rotatable relative to the transmission mechanism, and a stop mechanism associated with the shaft, the stop mechanism being transitionable between a first state and a second state. In the first state, the shaft is free to rotate in a first direction and in a second direction opposite to the first direction. In the second state, the shaft is constrained from rotating in one of the first direction or the second direction by a defined first endpoint of a range of rotational motion of the shaft. Devices and methods relate to rotation stop mechanisms.