Joint Finishing Tool Plate Locking Mechanism

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Solution Overview

Problem

Existing joint smoothers lack a secure and versatile mechanism for positioning and retracting a cutting edge, limiting their effectiveness in refining joints filled with joint compound.

Innovation Solution

A joint smoother with a pocket in the head that secures a plate with a latching projection, allowing the plate to be easily pulled out and featuring multiple cutting edges for different angles and positions, enhancing the tool's usability and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plate with cutting edge is inserted into the pocket for reworking joints, then the tool can effectively smooth and rework joints filled with joint compound, but the plate may become loose or dislodged during use

Engineering Contradiction:
Improvesecure positioning of plateVSAvoideasy removal of plate
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The bridge is designed to be elastically deformable, allowing it to dynamically adapt between a locked state (when pressed against the upper broad side of the plate) and an unlocked state (when deflected to allow plate removal). This dynamic mechanism enables both secure positioning during use and easy removal when needed, resolving the contradiction between reliability and ease of operation.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a single cutting edge is provided on the plate, then the tool structure remains simple, but the tool lacks versatility for different joint configurations and angles

Engineering Contradiction:
Improvemultiple cutting edges for different anglesVSAvoidplate structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The plate is designed with multiple cutting edges (first, second, and third cutting edges) that can be selectively positioned at the pocket opening depending on the joint configuration required. This multi-functional design allows a single plate to handle various joint angles and positions, providing versatility without requiring multiple separate tools, thus resolving the contradiction between adaptability and device complexity.

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

3Reliability

If the bridge is made rigid to provide strong locking force, then the plate is securely held, but the bridge cannot elastically move away when plate removal is needed

Engineering Contradiction:
Improvelocking force strengthVSAvoidelastic deformability for plate removal
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The bridge is designed with specific material and geometric parameters that allow it to exhibit elastic deformability under controlled conditions. The bridge can maintain sufficient rigidity to provide strong locking force during normal operation, yet remains elastically deformable when force is applied to remove the plate. This parameter optimization resolves the contradiction between reliability (locking force strength) and adaptability (elastic deformability for plate removal).

Inventive Principle:
Principle #35Parameter changes

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

The solution provides a secure and versatile mechanism for positioning and retracting cutting edges, improving the tool's ability to smooth and rework joints filled with joint compound, offering enhanced functionality and user convenience.

Implementation Method 1

a bridge (12) arranged in the pocket (4) and designed to press against a lower broad side (28) of the plate (20) in order to exert a locking force on the plate (20)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

They are associated with a section of the elastic plate protruding from the pocket, allowing this section to deform elastically

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4209644B1Tool for finishing joints filled with a joint compound
Publication Date: 2024.06.26 WOLFCRAFT GMBH
  • EP4209644B1 patent drawingFigure 1
  • EP4209644B1 patent drawingFigure 2~3
  • EP4209644B1 patent drawingFigure 4~5

AI summary

The invention relates to a tool for finishing joints filled with a joint compound, comprising an elongated handle (1) and a head (2) attached to the handle (1). The head (2) has a pocket (4) which, on the side of the head (2) facing away from the handle (1), has an opening (5) in which a plate (20) made of an elastic material is inserted, the plate having a first cutting edge (22, 23) at its end projecting from the opening. According to the invention, a bottom wall (9) of the pocket (4) has a locking opening (10) into which a locking projection (21) of an upper broad side (27) of the plate (20) engages. A lower broad side 28 of the plate (20) can rest on an elastic rib (12) opposite the locking opening (10).