Broken Spark Plug Removal Kit Using Nested Porcelain Insertion

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Solution Overview

Problem

The removal of broken spark plugs from a cylinder head is challenging due to their difficult design, which often results in the spark plug tip breaking off and becoming lodged within the cylinder head, making extraction time-consuming and difficult, especially in Ford Motor Company vehicles as described in Technical Service Bulletin #TSB 06-15-2.

Innovation Solution

A tool kit comprising a first tool to push the porcelain insert into the tubular spark plug tip and a second tool to threadably connect with and extract the spark plug tip from the cylinder head, ensuring axial alignment and safe removal without damaging the threads or losing spark plug components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a threaded tool is used to remove the broken spark plug tip, then the tip can be extracted from the cylinder head, but the removal process becomes exceedingly time consuming and difficult to align

Engineering Contradiction:

Improveremoval speedVSAvoidalignment difficulty

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The porcelain insert is pushed into the hollow tubular metal tip, creating a nested configuration where the porcelain element is contained within the metal tip. This nested structure allows the entire assembly to be removed as a single unit, eliminating the need for threading operations and significantly reducing removal time and alignment difficulty.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The spark plug is divided into separable components: the threaded body that remains in the cylinder head and the tip portion containing the porcelain insert that can be removed. This segmentation allows the removable portion to be extracted without affecting the threaded bore, enabling quick replacement of spark plugs.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the porcelain insert remains outside the metal tip, then the tip can be accessed for removal, but the porcelain insert precludes appropriate retrieval of the spark plug tip

Engineering Contradiction:

Improvetip accessibilityVSAvoidremoval efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The porcelain insert is positioned inside the hollow tubular metal tip, creating a nested configuration. This allows the metal tip to encapsulate and protect the porcelain insert during removal, enabling the entire assembly to be extracted as one unit without the porcelain interfering with retrieval operations.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Ease of operation

If tapping threads are used to grip the spark plug tip, then the tip can be secured for removal, but the threads expand the tip and may cause damage

Engineering Contradiction:

Improvegrip securityVSAvoidtip integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The hollow tubular metal tip provides an inherent gripping surface through its outer circumference that engages with the cylinder head bore. This nested configuration eliminates the need for tapping threads into the tip, preventing expansion and potential damage to the fragile porcelain insert and metal tip structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS7814814B2Tool kit for removal of broken spark plugs

Publication Date: 2010.10.19 LISLE CORP

AI summary

A kit for removal of a broken spark plug from a cylinder head includes first and second tools. The first tool is designed to position a broken porcelain element into the spark plug tip so that the second tool may be utilized to engage the tip by threading into the tip and thereafter axially withdraw the plug tip from the cylinder head by rotation of the tool.