Medical Support Arm Link Layout for Better Load Balancing

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Solution Overview

Problem

Current medical device support systems with load balancing arms have suboptimal force transmission due to short links that attach to the proximal end of the counterbalancing spring, leading to inefficient balancing and increased spring travel.

Innovation Solution

A load balancing arm design where the link connects at its proximal end to an adjustment bearing element and at its distal end to the counterbalancing spring, allowing for a longer link and improved force transmission, reducing spring travel and enhancing balance throughout the pivotable range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the link is made shorter and attached to the proximal end of the spring, then the device complexity is reduced, but the force transmission efficiency deteriorates and spring travel increases

Engineering Contradiction:
Improvelink lengthVSAvoidforce transmission efficiency
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent inverts the conventional attachment arrangement by connecting the link to the distal end of the spring instead of the proximal end. This reversal of the attachment point allows the link to be longer while maintaining compact overall dimensions, thereby improving force transmission efficiency without significantly increasing device complexity

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent reconfigures the spatial arrangement of components by positioning the link-spring connection at the distal end, effectively utilizing the longitudinal dimension of the support arm. This dimensional reorganization enables longer link length for better force transmission while keeping the proximal end attachment points fixed

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the link is made shorter and attached to the proximal end of the spring, then the device complexity is reduced, but the spring travel increases

Engineering Contradiction:
Improvelink configurationVSAvoidspring travel
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

By inverting the attachment configuration and connecting the link to the distal end of the spring rather than the proximal end, the patent reduces the required spring travel distance. The longer link provides better mechanical leverage, allowing the spring to achieve the same balancing effect with less travel, thereby reducing the overall movement range required

Inventive Principle:
Principle #13The other way round (Inversion)

3Force

If the link is made longer by attaching to the distal end of the spring, then the force transmission improves, but the device complexity increases

Engineering Contradiction:
Improveforce transmissionVSAvoidlink attachment configuration
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent applies the inversion principle by reversing the conventional attachment arrangement. Instead of connecting the link to the proximal end of the spring, it connects to the distal end. This simple configuration reversal enables longer link length for improved force transmission without requiring complex additional components or mechanisms

Inventive Principle:
Principle #13The other way round (Inversion)

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 design achieves better force transmission and reduced spring travel, resulting in a more balanced load balancing arm, effectively counteracting the moments generated by medical device loads across the pivotable range.

Implementation Method 1

a spring extending within a cavity of the support arm and mounted to exert a biasing force between the main pivot axis and a distal end of the spring

Methodology Applied
Scientific EffectSpring biasing force: Spring

Implementation Method 2

at least one link having a proximal end pivotably mounted to the adjustable bearing element for pivotable movement about the adjustable pivot axis, and a distal end pivotably mounted to the distal end of the spring such that the biasing force exerted by the spring is transmitted through the link

Methodology Applied
Scientific EffectForce transmission through link: Lever

Data Source

PatentEP3917439B1Load balancing arm for medical device support system
Publication Date: 2022.10.12 AMERICAN STERILIZER CO
  • EP3917439B1 patent drawingFigure 1
  • EP3917439B1 patent drawingFigure 2~3
  • EP3917439B1 patent drawingFigure 4~5

AI summary

A load balancing arm for a medical device support system. The load balancing arm includes a proximal hub, an adjustable bearing element, a support arm, a spring and a link. A distal end of the support arm is configured to support a medical device load and a proximal end is pivotably mounted to a main bearing element for pivotable movement about a main pivot axis. The spring extends within a cavity of the support arm and is mounted to exert a biasing force between the main pivot axis and a distal end of the spring. The link has a proximal end pivotably mounted to the adjustable bearing element for pivotable movement about an adjustable pivot axis, and a distal end pivotably mounted to the distal end of the spring such that the biasing force exerted by the spring is transmitted through the link to the adjustable bearing element.