Guide Jacket Force Sensor for Continuous Media

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Solution Overview

Problem

Existing force sensors that measure tension and compression in linear media often require interrupting or altering the medium, which can lead to catastrophic failure and system disruption.

Innovation Solution

A force sensor with an instrumented flexure body that allows the medium to pass uninterrupted, using a high modulus of elasticity material with a longitudinal passage and stress-concentration area, instrumented with strain gages to measure forces without altering the medium's path, and attached at spaced points to enable both tension and compression measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor is installed as a mechanical link directly in the force-transmitting medium by interrupting the medium, then the sensor can measure forces directly, but the catastrophic failure of the sensor or its attachment interrupts operation of the entire system

Engineering Contradiction:
Improveforce measurement capabilityVSAvoidsystem operational continuity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The sensor is divided into separate components: a flexure body with a longitudinal passage that allows the medium to pass through uninterrupted, and attachment means at spaced points along the passage. This segmentation allows the sensor to measure forces without being a single-point failure source, as the medium can bypass the sensor if needed while measurement function remains intact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexure body acts as an intermediary element that transfers a portion of the elastic deformation from the medium to the strain gages. The medium passes through the flexure body without being interrupted, while the flexure body's elastic deformation, caused by attachment at spaced points, provides the measurement signal through strain gages, thus mediating between the medium and the measurement system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the medium is interrupted and the sensor is attached to rejoin the two resulting lengths, then force measurement is achieved, but the system complexity increases and installation becomes more difficult

Engineering Contradiction:
Improveforce measurement capabilityVSAvoidinstallation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flexure body serves multiple functions simultaneously: it provides a passage for the medium to pass through uninterrupted, acts as an elastic element that deforms under load, supports strain gages for measurement, and includes attachment means for securing to the medium at spaced points. This multi-functionality reduces overall system complexity compared to interrupting the medium and joining separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensor design nests the medium passage within the flexure body structure. The longitudinal passage is integrated into the flexure body, allowing the medium to pass through the interior of the sensor assembly without requiring external routing or interruption of the medium, thereby simplifying installation and reducing device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Speed

If the flexure body is made of high modulus of elasticity material, then the sensor can operate in dynamic fashion with improved response, but the device size may increase

Engineering Contradiction:
Improvedynamic response capabilityVSAvoidsensor size
Core Design Contradiction:
SpeedVSVolume of moving object

Solution Approach 1:

The patent utilizes changes in the physical parameters of the flexure body, specifically its elastic modulus and geometric dimensions, to optimize performance. By carefully selecting the modulus of elasticity and configuring the flexure body's geometry (including the longitudinal passage and attachment point locations), the sensor achieves rapid dynamic response while maintaining a compact size suitable for miniaturization in applications like surgical robotics.

Inventive Principle:
Principle #35Parameter changes

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

Enables accurate and continuous measurement of forces without interrupting the medium, providing reliable operation and miniaturization for applications like surgical robotics.

Implementation Method 1

a portion of the flexure body is elastically deformed when the medium stretches or compresses under load

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The flexure body is strategically configured as hereinafter described to provide a strain-concentration area between the ends that can deform in one or both of tension and compression modes. This area can be instrumented such as by bonded-in-place strain gages or similar devices to produce electrical outputs correlated to the force being transmitted through the medium.

Methodology Applied
Scientific EffectStrain gage measurement: Piezoresistive Effect

Data Source

PatentEP3903081B1Guide jacket force sensor
Publication Date: 2023.10.11 FUTEK ADVANCED SENSOR TECH
  • EP3903081B1 patent drawingFigure 1~2
  • EP3903081B1 patent drawingFigure 3~5
  • EP3903081B1 patent drawingFigure 6~7

AI summary

A load sensor is designed to be mounted on a continuous force-applying medium such as a cable so as to deform according to the force transmitted through the medium. The sensor includes a body having a longitudinal through-passage for the medium and is mechanically secured to the medium only at the opposite ends of the body. A lateral hole provides a strain concentration area with zones that are instrumented with strain gages. The sensor body can be enclosed to provide support for a wrap-around lead carrier.