Avionics Cam Retainer Assembly for High-Preload Unit Retention

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Solution Overview

Problem

Existing cam retainer assemblies for securing removable electronic units in avionics equipment mounting trays are often expensive, large, heavy, and cumbersome, lacking efficient and cost-effective solutions for secure retention.

Innovation Solution

A cam retainer assembly with a swing arm and latch mechanism, featuring a cam surface that pivots between a released and retained state, providing high clamping force without obstructing unit removal, and utilizing a catch device for secure engagement with the electronic unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If swing bolts are used to retain electronic units in the tray, then high clamping forces are achieved, but the device becomes expensive, large, heavy, and awkward for packaging

Engineering Contradiction:
Improveclamping forceVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The retainer assembly is divided into separate functional components: a cam mechanism for generating clamping force, a swing arm for positioning, and a latch for retention. This segmentation allows each component to be optimized independently and simplifies the overall structure compared to traditional swing bolts

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the traditional swing bolt mechanical system with a cam-based retention system. The cam mechanism converts rotational motion into linear clamping force, eliminating the need for threaded fasteners and complex adjustment mechanisms while maintaining high clamping forces

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional retaining devices are used, then secure retention is achieved, but the devices are large and heavy

Engineering Contradiction:
Improveretention securityVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the geometric parameters of the cam mechanism to optimize the force multiplication ratio. By adjusting the cam profile and leverage arms, high clamping forces are achieved with minimal actuator force, reducing the size and weight of required components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The retainer assembly utilizes composite construction with lightweight materials such as aluminum alloys or engineered plastics for non-critical components, maintaining structural integrity while reducing overall weight compared to traditional all-metal swing bolt assemblies

Inventive Principle:
Principle #40Composite materials

3Reliability

If cam retainer assemblies are used, then secure retention is achieved, but assembly and removal require tools and are cumbersome

Engineering Contradiction:
Improveretention securityVSAvoidease of installation and removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The cam mechanism is designed to be manually operated without tools. The operator can directly actuate the cam through a accessible interface, and the self-latching feature automatically secures the electronic unit once the cam is rotated into the locked position, eliminating the need for separate tool operations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The swing arm provides dynamic positioning capability, allowing the cam mechanism to swing into and out of the engagement position with the electronic unit. This dynamic motion enables tool-free installation and removal while maintaining secure retention when engaged

Inventive Principle:
Principle #15Dynamics

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 secure, high-preload retention of electronic units with reduced assembly costs and tool-free installation/removal, ensuring reliable and efficient operation.

Implementation Method 1

the cam surface is not in contact with the removable electronic unit when in the released state, and the cam surface is in contact with the removable electronic unit when in the retained state

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

a swing arm including a first end segment pivotally connected to the avionics equipment mounting tray at a first pivot axis, and an opposite second end segment pivotally connected to the base portion at a second pivot axis

Methodology Applied
Scientific EffectPivoting: Hinge

Data Source

PatentEP3490350B1Avionics cam retainer assembly
Publication Date: 2023.10.11 HAMILTON SUNDSTRAND CORP
  • EP3490350B1 patent drawingFigure 1
  • EP3490350B1 patent drawingFigure 2~4

AI summary

A retainer assembly (22) is adapted to secure a removable electronic unit (24) within an avionics equipment mounting tray (26). The retainer assembly includes a latch (48) having a base portion (60) and a handle portion (66). The base portion is pivotally coupled to one of the removable electronic unit and the avionics equipment mounting tray. The handle portion projects outward from the base portion. The base portion includes a cam surface (68) adapted to releasably contact the other of the removable electronic unit and the avionics equipment mounting tray.