Force Transmission Mechanisms for Offset Drive Articulation
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Solution Overview
Problem
Existing force transmission mechanisms in instruments face challenges due to limited space, high friction environments, and the need for compact, robust, and reliable systems that can adapt to existing instrument shaft and manipulator designs, particularly in applications where input drive members are laterally offset from the instrument shaft.
Innovation Solution
The implementation of a steerable instrument with a shaft featuring an articulable segment and a force transmission mechanism that includes rotatable drive components with axes offset from the shaft's longitudinal axis, coupled via a rotatable coupler mechanism to push-pull actuation elements, allowing for translation of these elements to articulate the segment, and a rotatable coupler mechanism that rotates about the shaft to cause translation of the actuation elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force transmission mechanism uses traditional components (capstans, gears, linkages) to convert rotational input forces to translational forces, then the mechanism can transmit force to articulate moveable components, but the mechanism occupies excessive space and becomes complex in high-friction environments
Solution Approach 1:
The patent extracts and eliminates traditional force transmission components (capstans, gears, linkages) from the system. Instead of using these separate components to convert rotational motion to translational motion, the invention integrates the force transmission function directly into the actuation elements themselves, which are pulled through a friction fit engagement with the shaft to directly articulate the moveable component.
Solution Approach 2:
The actuation elements serve multiple functions: they transmit force from the input drive member, convert rotational motion to translational motion, and directly articulate the moveable component. This multi-functionality eliminates the need for separate specialized components, reducing overall system complexity while maintaining reliability.
2Volume of moving object
If the force transmission mechanism is compacted to fit limited space constraints, then the instrument becomes more adaptable to existing shaft designs, but the mechanism operates in a high-friction environment that reduces durability
Solution Approach 1:
The actuation elements are nested within the shaft structure, passing through it in a pulled configuration. This nesting approach allows the force transmission mechanism to be compact and integrated within the existing shaft design while maintaining sufficient clearance to avoid excessive friction. The actuation elements are routed through the shaft rather than requiring separate external transmission components.
3Adaptability or versatility
If input drive members are positioned laterally offset from the instrument shaft to adapt to existing designs, then the mechanism can integrate with existing manipulator systems, but traditional force transmission components require complex linkages to bridge the offset
Solution Approach 1:
The actuation elements serve as intermediaries that directly connect the laterally offset input drive member to the moveable component. Instead of using complex linkages to bridge the offset, the actuation elements are pulled through the shaft structure, providing a direct force transmission path that simplifies the mechanism while maintaining adaptability to existing shaft and manipulator designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient force transmission in a compact space, providing robust and reliable articulation of instrument components, even in high-friction environments, while adapting to existing designs and facilitating simultaneous, opposing movements of actuation elements.
Implementation Method 1
a rotatable coupler mechanism coupling one of the one or more rotatable drive components to the one or more push-pull actuation elements, the rotatable coupler mechanism configured to rotate about the longitudinal axis of the shaft in response to rotation of the one of the one or more rotatable drive components to cause translation of the one or more push-pull actuation elements
Data Source
AI summary
A steerable instrument includes a shaft comprising an articulable segment; a force transmission mechanism at the proximal end portion of the shaft, the force transmission mechanism comprising one or more rotatable drive components having axes of rotation spaced from the longitudinal axis of the shaft, the one or more rotatable drive components configured to be rotatably driven by respective drive input torques; one or more push-pull actuation elements configured to translate to transmit compressive forces to the articulable segment; and a rotatable coupler mechanism coupling one of the one or more rotatable drive components to the one or more push-pull actuation elements, the rotatable coupler mechanism configured to rotate about the longitudinal axis of the shaft in response to rotation of the one of the one or more rotatable drive components to cause translation of the one or more push-pull actuation elements.