Adjustable Moment Counterweight for Angle of Attack Sensor

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Solution Overview

Problem

Existing angle of attack sensors with rotatable vanes face challenges in maintaining balance against gravitational forces, leading to erroneous measurements, especially at lower air speeds, and are susceptible to unbalancing due to vibration or impact.

Innovation Solution

An adjustable moment counterweight assembly that allows for fine adjustment and secure locking of the counterweight moment, extending the moment adjustability range two to three times more than current systems, and is manufactured from corrosion-resistant materials to prevent unbalancing and failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed counterweight assembly is used to balance the vane, then gravitational balance is achieved, but the system becomes susceptible to unbalancing due to vibration or impact and cannot be adjusted for different operational conditions

Engineering Contradiction:
Improveresistance to unbalancingVSAvoidadjustability range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The counterweight assembly transitions from a fixed configuration to a dynamic, adjustable system. The counterweight can be repositioned along the counterweight arm to different locations, allowing the moment of inertia to be adjusted for different gravitational balance requirements. This dynamic adjustability enables the system to adapt to various operational conditions while maintaining reliability through secure locking mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The counterweight assembly is divided into separable components: a counterweight, a counterweight arm, and a mounting structure. This segmentation allows the counterweight to be independently positioned and locked at different locations along the arm, providing both adjustability and secure fixation. The modular design enables fine adjustment of the center of gravity while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a simple counterweight design is used, then manufacturing is easier, but the moment adjustability range is limited and cannot extend two to three times beyond current systems

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmoment adjustability range
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The counterweight position is adjusted along the longitudinal axis of the counterweight arm, adding a dimensional aspect to the adjustment mechanism. By moving the counterweight to different distances from the rotation axis, the system achieves a moment adjustability range two to three times greater than conventional fixed designs, while maintaining manufacturing simplicity through a linear adjustment path.

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

Solution Approach 2:

The counterweight assembly serves multiple functions: it provides gravitational balance, allows for moment adjustment across an extended range, and maintains structural simplicity. The same basic components (counterweight, arm, mounting structure) enable both fixed and adjustable configurations, making the system universally applicable to different balance requirements without increasing manufacturing complexity.

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

3Adaptability or versatility

If adjustment mechanisms are added to the counterweight, then moment adjustability is improved, but the system becomes more susceptible to loosening under vibration and impact

Engineering Contradiction:
Improvemoment adjustabilityVSAvoidresistance to loosening
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking mechanism is designed to preemptively counteract the effects of vibration and impact. Once the counterweight is positioned at the desired location, the locking feature secures it in place before any loosening can occur. This prior cushioning approach prevents the adjustment mechanism from loosening under operational vibrations and impacts, maintaining both adjustability and reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

A locking mechanism acts as an intermediary between the adjustable counterweight position and the structural integrity requirement. This intermediary component (locking feature) transfers the adjusted position into a secure, fixed state that can withstand vibration and impact, thereby mediating between the need for adjustability and the need for reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If standard materials are used for the counterweight assembly, then manufacturing cost is lower, but corrosion can cause unbalancing and failure over time

Engineering Contradiction:
Improvemanufacturing costVSAvoidresistance to corrosion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The counterweight assembly utilizes corrosion-resistant materials for all components, including the counterweight, counterweight arm, and mounting structure. This material selection ensures that the assembly maintains its balance and structural integrity over time by preventing corrosion, which could otherwise cause unbalancing and failure. The use of uniform corrosion-resistant materials throughout the assembly eliminates differential corrosion between dissimilar materials.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3753852B1Adjustable moment counterweight with multiple locking methods
Publication Date: 2023.05.17 ROSEMOUNT AEROSPACE INC
  • EP3753852B1 patent drawingFigure 1
  • EP3753852B1 patent drawingFigure 2
  • EP3753852B1 patent drawingFigure 3A~3B

AI summary

An adjustable moment counterweight assembly (16) for an angle of attack sensor (10) includes a fixed counterweight (42) configured to fixedly attach to a shaft (14) of the angle of attach sensor, the shaft (14) being rotatable about an axis; an adjustable counterweight (46) configured to move in a radial direction relative to the fixed counterweight (42) via rotation of a threaded member (58); and a first fastener (51) in operable communication with the fixed counterweight (42) and the adjustable counterweight (44, 46) such that the first fastener (51) can fixedly attach the adjustable counterweight (44, 46) to the fixed counterweight (42).