Elastomeric Skimming Tool Recessed Handle Design
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Solution Overview
Problem
Conventional plaster 'ruling off' levelling tools, such as the 'Darby', are rigid and inflexible, making them unsuitable for smoothing and levelling wet finish coat plaster, and elastomeric blades held in metal handles can kink or buckle due to differential expansion under ambient conditions.
Innovation Solution
A skimming tool with an elastomeric, elongate, rectangular, flat, flexible web and a substantially rigid handle that allows sliding movement along a recessed channel, preventing perpendicular movement and accommodating differential expansion, combined with an ergonomic design and ridged surface for improved plaster engagement and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomeric blade is held rigidly in a metal handle, then the blade is securely positioned, but the blade tends to kink or buckle due to differential expansion under ambient conditions
Solution Approach 1:
The handle is formed with a recess that receives and holds the elastomeric blade in a slack fit, allowing the blade to flex and expand without rigid constraints. This flexible accommodation prevents kinking and buckling while maintaining secure positioning during use.
Solution Approach 2:
The recess in the handle is designed with specific dimensional parameters that allow for thermal expansion of the elastomeric blade. The slack fit provides clearance for expansion while maintaining functional engagement, resolving the contradiction between secure positioning and shape stability.
2Stability of the object's composition
If a rigid Darby tool is used for ruling off backing plaster, then the tool provides structural stability, but it is inflexible and unsuitable for smoothing wet finish coat plaster
Solution Approach 1:
The tool is segmented into two distinct functional parts: a rigid handle for structural stability and user grip, and a flexible elastomeric blade for adapting to surface contours. This segmentation allows each part to optimize its properties without compromising the other.
Solution Approach 2:
The tool combines two different material types - a rigid handle material (such as metal or hard plastic) and a flexible elastomeric blade material. This composite construction provides both structural stability and flexibility, enabling the tool to perform multiple functions from ruling off to smoothing various plaster types.
3Adaptability or versatility
If the web is made flexible for smoothing finish coat plaster, then the tool can adapt to surface contours, but the web may move or detach from the handle
Solution Approach 1:
The recess in the handle is designed to accommodate the flexible web through a slack fit that allows movement and expansion while preventing detachment. The geometry of the recess creates frictional engagement and physical barriers that secure the web during normal use.
Solution Approach 2:
The recess acts as an intermediary structure between the handle and the web, providing a transition zone that allows the web to flex and expand while maintaining secure connection. The recess geometry mediates between the conflicting requirements of flexibility and connection reliability.
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 tool provides effective smoothing and levelling of wet finish coat plaster with enhanced flexibility and durability, preventing kinking and buckling, while allowing for comfortable grip and efficient plaster handling, resulting in a flatter finish and reduced mess.
Implementation Method 1
expansion of the web and the handle may vary differently under ambient conditions
Implementation Method 2
ridged surface for improved plaster engagement and distribution
Data Source
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AI summary
A skimming tool 1 for smoothing and levelling wet plaster applied to a surface comprising: an elongate generally rectangular, flat, flexible, elastomeric web 2 and an elongate, substantially rigid handle 3 connected to and extending along substantially the length of one long edge of the web, wherein the handle is adapted to be gripped by the user