Fastener System Preventing Gravity Dropout in Radial Assemblies

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Solution Overview

Problem

In large radial assemblies, existing fasteners dispersed evenly around a 360-degree circumferential area are prone to falling out due to gravity, posing a challenge in complex machine environments.

Innovation Solution

A fastener system featuring a bushing with internal threads and a reduced diameter shank bolt, where the bushing is held in place by a snap ring, preventing the bolt from falling out through axial contact of the components' threads, allowing for rotational alignment of a mating flange while maintaining secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If fasteners are dispersed evenly around a 360-degree circumferential area in large radial assemblies, then the fasteners can provide uniform structural support, but gravity causes the fasteners to fall out into complex areas of the machine

Engineering Contradiction:
Improvestructural support stabilityVSAvoidfastener retention
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The fastener system is divided into separate functional components: a bolt with reduced diameter shank, a bushing with internal threads, and a snap ring. This segmentation allows each component to perform its specific function - the reduced shank enables full threading, the bushing provides the threaded interface, and the snap ring prevents gravitational dropout, collectively solving both structural support and retention requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bushing acts as an intermediary component between the bolt and the housing. It receives the reduced diameter shank of the bolt, provides the threaded interface for secure engagement, and is retained by the snap ring in the housing. This intermediary structure enables the bolt to be fully threaded while preventing the fastener assembly from falling out due to gravity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the bolt has a reduced diameter shank to allow full threading through the bushing, then the bolt can be fully threaded through the internal threads of the bushing, but the bolt and bushing must be precisely aligned during assembly

Engineering Contradiction:
Improvethreading capabilityVSAvoidalignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The bushing is pre-installed into the housing and secured with the snap ring before the bolt is inserted. This preliminary action establishes a fixed reference position for the bushing, ensuring that when the bolt is subsequently inserted and threaded, the alignment is already predetermined by the bushing's position in the housing, thereby reducing the actual alignment precision required during the final assembly step

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2336580B1Fastener system
Publication Date: 2016.08.24 UNITED TECH CORP
  • EP2336580B1 patent drawingFigure 1~2
  • EP2336580B1 patent drawingFigure 3

AI summary

A fastener system (60) is disclosed that when assembled prevents the assembly from accidently falling out of a housing (30). The fastener system (60) includes a reduced shank bolt (22), a bushing (10) with internal threads (12) and a snap ring relief (16), a snap ring (40), and a housing (30) modified to receive the bushing (10) and the snap ring (40). A flange (50) to which the housing (30) is attached may have a flange relief (51) to seat the snap ring (40) when the bushing (10) is fully engaged with the flange (50).