Projectile Gas-Tight Conduit Using Metallic Base Body Ground

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Solution Overview

Problem

Existing projectiles with timed fuzes face challenges in creating a simple, gas-tight electrical feedthrough for signal and ground lines, particularly under high pressure and temperature conditions, where complex components are required to prevent gas penetration and withstand high accelerations during firing.

Innovation Solution

A gas-tight bushing is achieved using an insulated outer body with a metallic, conductive inner conductor, where the metallic base body forms the ground line and the signal line is routed through a bore within this body, coated with an electrically insulating material, and connection contacts are secured with an insulating adhesive to ensure reliable insulation and gas-tight signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex gas-tight bushings and independent feedthrough components are used, then gas-tightness and reliability are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvegas-tightnessVSAvoidbushing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the gas-tight bushing function and electrical feedthrough function into a single integrated cable assembly. The cable includes insulated conductors that pass through a gas-tight seal structure, eliminating the need for separate bushing components and independent feedthrough assemblies. This integration maintains gas-tightness while reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cable assembly serves multiple functions simultaneously: it provides electrical signal transmission, ground connection, and gas-tight sealing. The insulated conductors within the cable fulfill both electrical and sealing roles, making the cable a multi-functional component that replaces several separate parts.

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

2Reliability

If complex gas-tight bushings are used to prevent gas penetration, then gas-tightness is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvegas-tightnessVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The gas-tight sealing function and electrical connection function are merged into a single cable assembly that can be installed as one unit. This eliminates the need for separate assembly steps for bushings and feedthroughs, significantly simplifying the manufacturing and assembly process while maintaining gas-tight integrity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If separate gas-tight feedthrough components are used, then gas-tightness is ensured, but productivity and assembly efficiency decrease

Engineering Contradiction:
Improvegas-tightnessVSAvoidassembly efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The cable assembly integrates gas-tight sealing and electrical feedthrough functions into a single pre-assembled unit. This allows the entire assembly to be installed in one operation rather than requiring separate installation of multiple components, significantly improving assembly efficiency and productivity while ensuring gas-tightness.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If the base body is coated with insulating material before signal line insertion, then electrical insulation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectrical insulationVSAvoidmanufacturing steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating coating is applied to the base body in advance, before the signal line is inserted into the bore. This preliminary action ensures that the insulation layer is already in place to prevent electrical contact between the signal line and the conductive base body, simplifying the overall manufacturing process by eliminating the need for post-assembly insulation measures.

Inventive Principle:
Principle #10Preliminary action

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

This design provides a robust, easy-to-assemble, and EMC-resistant electrical connection that simplifies the loading of a propellant charge igniter, ensuring reliable contact and resistance to gas pressure, while maintaining ballistic-proof integrity.

Implementation Method 1

a non-conductive coating on all sides, i.e. also inside all bores to be insulated and over all threads

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

The threaded areas of the connection contacts are also wetted with an electrically insulating liquid adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2141444B1Electrical, gas tight conduit in a projectile
Publication Date: 2014.08.06 RHEINMETALL WAFFE MUNITION GMBH
  • EP2141444B1 patent drawingFigure 1
  • EP2141444B1 patent drawingFigure 2~3
  • EP2141444B1 patent drawingFigure 4

AI summary

A direct connection or contact between, for example, a propellant igniter (10) and a base body (6), such as a projectile tail, is proposed. To ensure that the signal line (16) and the ground line (22) can be routed through the base body or tail section (6) in a manner that is resistant to firing, the invention further proposes using the metallic base body (6) itself as the ground line (22) and routing only the signal line (16) insulated within the base body (6) through a corresponding bore (15) in the base body (6). The signal line (16) is insulated from the ground line (22) by a coating of an electrically insulating material (19) applied to the base body (6) before the signal line (16) is inserted into the bore (15).The two ends (23, 24) of the signal line (16) are provided with connection contacts (9, 12) which are preferably at least partially screwable into the base body (6) and are insulated from the base body (6). For contacting the ground line (22) formed by the base body (6) itself, the front (13) and the back (14) of the base body (6) are provided with uncoated blind holes (20, 21).