Fixed Square Assembly with Reamed Holes for Angular Accuracy

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Solution Overview

Problem

Conventional methods for manufacturing fixed squares face challenges such as requiring accurate production equipment, difficulty in working with different materials, and potential loss of angular accuracy over time due to the triangular configuration of holes and pins.

Innovation Solution

The method involves providing pre-made holes in the blade and stock, enlarging them using a reamer, and attaching them with fastening elements like pins or rivets in a fixture to ensure precise alignment and strength, with the blade and stock being made of materials like stainless steel and anodised aluminium, respectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If three holes are drilled through the blade and stock using conventional drilling, then the blade and stock can be joined, but the manufacturing precision is difficult to achieve due to tight tolerances and different materials

Engineering Contradiction:
Improvehole alignment precisionVSAvoidmanufacturing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by providing pre-made holes in the blade and stock before assembly. These pre-formed holes eliminate the need for precise drilling during final assembly, allowing the components to be joined with simple alignment in the fixture without requiring high-precision drilling equipment or tight tolerances.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If drilling is performed on different materials (steel blade and plastic stock) with the same tool, then the manufacturing process is simplified, but the manufacturing precision deteriorates

Engineering Contradiction:
Improveprocess simplicityVSAvoidhole precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by pre-forming holes in each material separately using appropriate methods for each material type, then bringing the components together for assembly. This allows each material to be processed with its optimal method while maintaining overall process simplicity.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If three pins are inserted into drilled holes to join the blade and stock, then the components are attached, but the angular accuracy is lost over time due to wear and loosening

Engineering Contradiction:
Improveassembly simplicityVSAvoidangular accuracy retention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies merging by combining multiple attachment points (three or more attachment elements distributed across the blade-stock interface) into a unified attachment system. This distributed attachment approach prevents localized wear and loosening, maintaining angular accuracy over time while keeping the assembly process simple.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If the blade and stock are joined with small holes and pins, then the attachment is achieved, but the strength and durability of the square is insufficient

Engineering Contradiction:
Improveattachment accuracyVSAvoidjoint strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies composite materials by using a combination of attachment elements (such as pins, rivets, or screws) in conjunction with the pre-formed holes and fixture alignment system. This composite attachment approach provides both precision positioning and high strength, ensuring the square remains durable even when dropped from heights.

Inventive Principle:
Principle #40Composite materials

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 approach reduces shavings, ensures accurate attachment, and results in a strong square that maintains angular accuracy even when dropped, with the enlarged holes and fastening elements providing enhanced durability.

Implementation Method 1

enlarging the at least three first and second holes while the blade and the stock are held in the fixture

Methodology Applied
Scientific EffectMaterial removal through reaming: Abrasion

Implementation Method 2

The pins may be secured by means of interference fit

Methodology Applied
Scientific EffectInterference fit: Friction

Data Source

PatentEP4435373A1Method of manufacturing a fixed square
Publication Date: 2024.09.25 HULTAFORS GROUP AB
  • EP4435373A1 patent drawingFigure 1
  • EP4435373A1 patent drawingFigure 2~3
  • EP4435373A1 patent drawingFigure 4~5

AI summary

A method of manufacturing a fixed square (10), comprising: providing a blade (12) of the square, wherein the blade has at least three first holes (14a-c); providing a stock (16) of the square, wherein the stock has at least three second holes (18a-c) corresponding to the at least three first holes of the blade for attaching the blade and the stock to each other; holding the provided blade and stock in a fixture (17) in a right angle relationship where the at least three first holes of the blade align with the at least three second holes of the stock; enlarging the at least three first and second holes while the blade and the stock are held in the fixture; and attaching the blade and the stock to each other using fastening elements (20a-c) in the at least three enlarged first and second holes (14a'-c', 18a'-c') while the blade and the stock are held in the fixture. The present invention also relates to a fixed square.