Profiled Wood Patch for Groove Repair

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Solution Overview

Problem

Existing methods for repairing wood panels with defects, such as knotholes and cracks, using wood patches are inefficient due to issues like unsuitable patch shapes, low bond strength, and high production costs, as well as the risk of damaging the patch's edges during insertion.

Innovation Solution

A wood patch design with a slightly wider central area and narrower ends, allowing easy insertion into a rectangular groove without resistance, and featuring small indentations and bulges that prevent edge contact, ensuring secure adhesion and automatic centering within the groove.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cylindrical drill is used to create a conical depression for wood patches, then the patch insertion is simplified, but the patches become circular in shape which is visually unappealing and unsuitable for cracks

Engineering Contradiction:
Improvepatch insertion processVSAvoidpatch shape
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The wood patch is divided into multiple segments (typically three rectangular pieces) that are joined together to form an elongated patch suitable for filling cracks and linear defects, rather than using a single circular patch

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of shaping the patch to fit a pre-formed conical hole, the invention creates a rectangular groove and inserts a rectangular patch that fits within it, inverting the traditional approach of using cylindrical drills and circular patches

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

2Adaptability or versatility

If a V-shaped groove is created and multiple wood pieces are hammered in, then elongated defects can be filled, but the patches are not form-fitting and bond strength is low

Engineering Contradiction:
Improveability to fill elongated defectsVSAvoidbond strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The rectangular groove is pre-formed with precise dimensions before patch insertion, ensuring that the patch will fit snugly and provide maximum bond strength upon insertion

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Adhesive is applied to the groove surfaces to create a strong bonding interface between the patch and the wood, replacing the mechanical hammering method with a chemical bonding approach

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Ease of manufacture

If wood patches are inserted into grooves with rectangular openings, then the patches can be easily manufactured, but the edges of the patch are at risk of breaking during insertion

Engineering Contradiction:
Improvepatch manufacturingVSAvoidedge integrity during insertion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Rounding fillets are created at the corners of the rectangular groove to eliminate sharp edges, providing a cushioning effect that prevents patch corner breakage during insertion while maintaining easy manufacturability

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If the groove walls are made parallel to each other, then the groove is easy to manufacture, but the patch cannot be securely retained without additional fixation devices

Engineering Contradiction:
Improvegroove manufacturingVSAvoidretention strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The groove design combines parallel walls for easy manufacturing with rounded corner fillets that provide mechanical interlocking and adhesive bonding surfaces, creating a composite geometric structure that achieves both manufacturability and retention strength

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2374586B1Wood patch with profiled bottom surface and wooden plate with groove and process for manufacturing a wood patch
Publication Date: 2015.07.29 LEHMANN ANDREAS
  • EP2374586B1 patent drawingFigure 1
  • EP2374586B1 patent drawingFigure 2

AI summary

The wooden plate (P) has a groove that is provided with a rectangle opening (N1) and two opposite walls (N2), which are provided flat and parallel to each other. Two connected front walls (N3) are provided with cylindrical segments. Two front surfaces (F3) are provided as wood patch (F) of the cylindrical segments. The radius of the front surfaces is same as the radius of the front walls of the groove. Front width of the front surfaces is smaller than groove width (N5). Independent claims are also included for the following: (1) a milling tool for manufacturing a wood patch; (2) a method for manufacturing wood patches; and (3) a method for patching a defect in a wooden plate.