Cable-Driven Locking Mechanism for Medical Support Arms
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Solution Overview
Problem
Conventional adjustable-position limb and/or instrument support arms for medical tables have limited range of motion, suffer from slippage, and are costly, failing to accommodate diverse patient needs and maintain position under substantial loads effectively.
Innovation Solution
A support arm system comprising a series of tubular elements connected by joints with locking mechanisms that can be simultaneously unlocked using an actuator, allowing for wide-range motion and reconfiguration, while maintaining position through spring-loaded locking mechanisms that return to a locked state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locking mechanisms are used at each joint, then the support arm can maintain position under load, but the range of motion is limited and the device becomes complex
Solution Approach 1:
Multiple locking mechanisms are merged into a single cable-driven system. The cable runs through all joints and when pulled, simultaneously actuates all locking mechanisms to unlock them. This allows the support arm to achieve wide range of motion across multiple joints while maintaining reliable position holding when locked, resolving the contradiction between position maintenance reliability and range of motion adaptability
2Reliability
If multiple locking mechanisms are provided at each joint, then position stability is improved, but the device complexity and cost increase
Solution Approach 1:
Instead of providing separate locking mechanisms at each joint, the invention merges multiple locking functions into a single cable-driven locking system. The cable passes through all joints and a single actuation event simultaneously engages or disengages all locking mechanisms across the entire support arm structure, reducing complexity while maintaining position stability
Solution Approach 2:
The cable-driven locking mechanism serves multiple functions simultaneously: it locks and unlocks all joints, provides position stability for multiple tubular elements, and enables wide range of motion when unlocked. This multi-functional design reduces the overall number of components needed while maintaining reliable position maintenance
3Reliability
If conventional support arms are designed for load bearing, then they can maintain position, but they are costly and have limited adjustability
Solution Approach 1:
The support arm transitions from a static, fixed-position design to a dynamic, multi-position adjustable design. Multiple tubular elements connected by joints with locking mechanisms allow the arm to be dynamically repositioned to various angles and configurations while maintaining load-bearing capability and position stability when locked
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
The system provides a wide range of motion, reliable position maintenance, and cost-effectiveness, enabling precise positioning of limbs and instruments during medical procedures with over 1.1×10^11 possible configurations.
Implementation Method 1
maintaining position through spring-loaded locking mechanisms that return to a locked state
Data Source
AI summary
An adjustable-position support arm comprising a plurality of tubular elements connected to one another in series of joints; a locking mechanism disposed at each joint so that a first portion of the locking mechanism is secured to a first tubular element of that joint and a second portion of the locking mechanism is secured to the second tubular element of that same joint wherein the locking mechanism is configured in a locked condition to prevent rotation of the first tubular element relative to the second tubular element selectively unlocked condition so that the first tubular element is rotatable relative to the second tubular element; and an actuator for actuating all of the locking mechanisms from their locked condition to their unlocked condition.