Splayed Cable Guide Grooves for Low-Friction Instrument Cable Routing
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Solution Overview
Problem
Existing medical instruments for minimally invasive surgery face challenges with complex and costly cable routing systems that increase friction, assembly time, and part count, necessitating a more efficient mechanism for routing tension members between the backend and wrist mechanisms.
Innovation Solution
A cable guide system with splayed guide grooves and bend portions allows for reduced friction and easier assembly, featuring a housing coupled to a medical instrument shaft with first and second guide grooves that are nonparallel, enabling the cables to slide smoothly through the shaft opening and reducing the likelihood of entanglement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pulleys and shafts are used to route control cables, then friction associated with cable movement is reduced, but cost, complexity, and assembly time increase
Solution Approach 1:
The patent removes the pulley component from the cable routing system entirely. Instead of using pulleys to guide the cables, the invention uses a simplified cable guide structure with grooves that directly route the cables from the backend mechanism to the wrist mechanism, eliminating the need for intermediate pulley components while maintaining low friction through proper groove geometry
Solution Approach 2:
The patent combines the cable guide function directly into the housing structure. The housing incorporates integrated cable guides with grooves that perform the same function as separate pulley assemblies, merging multiple components into a single integrated structure that reduces part count and assembly complexity while maintaining the friction-reducing cable routing function
2Loss of energy
If pulleys and shafts are used to route control cables, then friction associated with cable movement is reduced, but assembly time increases
Solution Approach 1:
By removing the pulley component and using direct groove-based cable guides integrated into the housing, the number of assembly steps is significantly reduced. The cables can be directly routed through the grooves without requiring pulley installation, alignment, and securing operations, thereby reducing assembly time while maintaining the friction-reducing benefit
Solution Approach 2:
The integration of cable guides into the housing structure eliminates the need for separate pulley assembly and installation steps. The grooves are formed as part of the housing manufacturing process, allowing cables to be routed directly during final assembly without requiring additional assembly operations for intermediate cable guidance components, thus reducing overall assembly time
3Ease of operation
If traditional cable routing mechanisms are used, then cable movement is guided, but part count increases
Solution Approach 1:
The patent merges the cable guide function directly into the housing structure, eliminating the need for separate pulley components. The housing incorporates integrated cable guides with grooves that perform the same function as separate pulley assemblies, reducing part count while maintaining effective cable routing and guidance throughout the instrument
Solution Approach 2:
The housing structure serves multiple functions: it provides structural support for the instrument, contains the cable routing system through integrated grooves, and guides cable movement from the backend to the wrist mechanism. This multi-functionality eliminates the need for dedicated separate components for each function, thereby reducing the overall part count while maintaining effective cable guidance
Data Source
AI summary
An apparatus includes a housing, a cable guide, a first cable, and a second cable. The housing is coupled to a shaft of a medical instrument. The cable guide is coupled to the housing, and defines a shaft opening into a passageway defined by the shaft. A first guide groove and a second guide groove are defined by the cable guide, with each of the first guide groove and the second guide groove being splayed outward from the shaft opening. The first cable is routed within the first guide groove and through the shaft opening, and is configured to slide within the first guide groove. The second cable is routed within the second guide groove and through the shaft opening, and is configured to slide within the second guide groove.