Joint Finishing Tool With Rounded Projection for Corner Smoothing

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Solution Overview

Problem

Existing tools for smoothing joint compounds in hard-to-reach places, such as corners between perpendicular components, often result in unsatisfactory visual outcomes and complex handling, with material removal and contamination issues.

Innovation Solution

A tool with a rounded projection on one end face and a central cutting edge, allowing for flexible and gentle processing of joints in corners and hard-to-reach areas, featuring a multi-dimensional curvature to prevent damage to previously smoothed joints and a design that facilitates easy handling and material containment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional plate-shaped tool with straight or curved end faces is used to smooth joints in hard-to-reach places, then the tool can access corner areas, but it damages previously smoothed joints and produces unsatisfactory visual results

Engineering Contradiction:
Improveaccess to hard-to-reach placesVSAvoidvisual quality of joint smoothing
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention replaces traditional straight or singly-curved end faces with a projection featuring multi-dimensional curvature (rounded in multiple directions). This spherical/ellipsoidal geometry allows the tool to conform to complex corner geometries while distributing contact pressure evenly, preventing damage to previously smoothed joints and achieving superior visual results in hard-to-reach areas.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If additional end faces are created by capping right-angled corners to enable dam-like joint fillings, then the tool can process perpendicular components, but the handling becomes complex and tool geometry leads to material contamination

Engineering Contradiction:
Improvecapability to process perpendicular componentsVSAvoidtool handling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The projection with multi-dimensional curvature serves multiple functions simultaneously: it can create dam-like joint fillings between perpendicular components, smooth joints in corner areas, and process various joint geometries. This single multi-functional projection replaces the need for multiple specialized end faces, simplifying tool handling while maintaining versatility.

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

3Ease of operation

If the tool has sharp or non-rounded edges to reach joint surfaces between perpendicular components, then the tool can access tight spaces, but joint compound removal occurs and visual appearance deteriorates

Engineering Contradiction:
Improveaccess to joint surfaces between perpendicular componentsVSAvoidjoint compound removal
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The projection features rounded ends with multi-dimensional curvature instead of sharp edges. This rounded geometry allows the tool to gently engage with joint surfaces in tight spaces between perpendicular components, distributing contact pressure to prevent joint compound removal while maintaining access to difficult-to-reach areas, thereby preserving visual appearance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4375453B1Tool for finishing and smoothing joints
Publication Date: 2025.08.06 FUGEN FRANZ GMBH
  • EP4375453B1 patent drawingFigure 1
  • EP4375453B1 patent drawingFigure 2
  • EP4375453B1 patent drawingFigure 3~5

AI summary

The present invention discloses a tool (10) for reworking and smoothing joints filled with a jointing compound, comprising a substantially plate-shaped body (12) with at least three end faces (1, 2, 3) preferably extending perpendicular to the plane of the plate and/or each bounded by two lateral edges (6), of which a first end face (1) has a flat profile and a second end face (2) has a convex profile. It is provided that a projection (20) is arranged on a third of the three end faces (1, 2, 3), which projects from the third end face (3) and has a rounded end section (22).