Infrared Detection Module Nut-Based Assembly for Compact Housing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The reduction in size of infrared detection modules due to higher operating temperatures makes it difficult to access and tighten the fixing screws, complicating the assembly process.

Innovation Solution

An infrared detection module with a fixing device that uses a nut capable of being screwed onto both the detector and cold machine casings, along with an indexing pin and orifice for alignment, eliminating the need for screws and simplifying the assembly by requiring only a single screwing operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the detection module dimensions are reduced to enable compact binoculars, then the size of the infrared detection module decreases, but the accessibility of fixing screws for tightening becomes difficult

Engineering Contradiction:
Improvedetection module sizeVSAvoidscrew tightening accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent inverts the traditional screw-fastening approach by using a nut that is screwed onto the detector housing rather than screws being inserted into the housing. This inversion allows the fastening operation to be performed from the outside of the compact module, making it accessible even in reduced dimensions. The nut can be tightened using standard tools applied to the external threaded surface, solving the accessibility problem while maintaining compact size.

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

Solution Approach 2:

The patent introduces an intermediary indexing pin that fits into an indexing hole during the assembly process. This intermediary element serves as a alignment tool that guides the relative positioning of the detector housing and cold machine housing before the nut is tightened. The indexing pin acts as a mediator that ensures proper alignment without requiring complex alignment procedures in the compact space.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple fixing screws are used to ensure tight sealing under high pressure, then the sealing reliability improves, but the assembly complexity and number of fastening operations increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoidfastening device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple fastening functions into a single nut assembly. Instead of using multiple separate fixing screws distributed around the housing, the design consolidates the fastening function into one centrally located nut that can be screwed onto the detector housing. This single nut performs the function of multiple screws, reducing assembly complexity while maintaining sealing reliability through the concentrated fastening force applied to the sealing interface.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The nut assembly serves multiple functions simultaneously: it provides the primary fastening force to secure the detector housing to the cold machine housing, it applies uniform pressure to maintain the seal against high refrigerant pressure (20 bar), and it can be tightened using a single standard tool. This multi-functionality reduces the overall complexity of the fastening system while ensuring reliable sealing under high pressure conditions.

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

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

Facilitates the assembly of the detector casing on the cold machine casing in reduced dimensions, ensuring secure sealing and alignment while reducing the complexity of the assembly process.

Implementation Method 1

The cooling section 8 includes a refrigeration unit (not shown in this figure) that cools the infrared detector to a temperature typically around 80 Kelvin

Methodology Applied
Scientific EffectRefrigeration: Cryogenics

Implementation Method 2

These screws must be tightened to high torques (on the order of 2 Newton-meters) to ensure a tight seal on the refrigeration unit housing. This is because the refrigeration unit housing contains a refrigerant gas subjected to high pressure (typically 20 bar) during operation of the refrigeration unit

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3143373B1Infrared detection module and associated infrared viewing device
Publication Date: 2020.11.11 SAFRAN ELECTRONICS & DEFENSE (FR)
  • EP3143373B1 patent drawingFigure 1
  • EP3143373B1 patent drawingFigure 2
  • EP3143373B1 patent drawingFigure 3

AI summary

The invention relates to an infrared detection module (4) comprising: a detection portion (7) comprising an infrared detector (16) and a detector housing (11) suitable for containing the infrared detector; a cold-production portion (8) comprising a refrigerating machine (39) for cooling the detector (16) and a refrigerating-machine casing (12) suitable for containing the refrigerating machine (39); and an attachment device (56) for attaching the detector casing (11) to the refrigerating-machine casing (12), the attachment device (56) comprising a nut (57) suitable for being screwed onto the detector housing (11) and/or onto the refrigerating-machine casing (12) so as to rigidly connect the casings to one another.