Cut Protection Layer With Elastic Stretching And Slip Surface

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Solution Overview

Problem

Existing cut protection solutions for manually operated saws, such as hand saws, are either cumbersome or insufficient in absorbing kinetic energy, leading to inadequate protection against cut injuries during work.

Innovation Solution

A cut protection system featuring an outer layer of elastically stretchable material over a smooth, slippery surface layer, where the elastic material absorbs kinetic energy by stretching and providing a restoring force to slow down the saw, allowing the saw to glide over the smooth surface, thereby reducing the thickness of additional protective layers required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple layers of thick ballistic nylon material are used for cut protection, then protection reliability is improved, but device complexity and bulkiness increase

Engineering Contradiction:
Improveprotection reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines a smooth slippery surface layer (first protective layer) with an elastically stretchable material layer (second protective layer) to create a composite structure that provides cut protection through multiple mechanisms: the smooth layer prevents saw teeth penetration while the elastic layer absorbs kinetic energy. This composite approach achieves reliable protection without requiring multiple thick layers of the same material, thereby reducing overall structural complexity and bulkiness.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If several layers of elastic material are arranged between cover layers, then kinetic energy absorption is improved, but the protective layer becomes thicker and more cumbersome

Engineering Contradiction:
Improvekinetic energy absorptionVSAvoidprotective layer thickness
Core Design Contradiction:
Loss of energyVSLength of stationary object

Solution Approach 1:

The protective system is segmented into two distinct functional layers: the first protective layer with smooth slippery surface that prevents penetration and facilitates sliding, and the second protective layer with elastically stretchable material that absorbs kinetic energy. This segmentation allows each layer to be optimized for its specific function, achieving effective energy absorption with reduced overall thickness compared to using multiple layers of the same elastic material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the protective system have different local properties: the first protective layer provides a smooth non-penetrable surface for preventing saw engagement, while the second protective layer provides elastic stretchability for energy absorption. This local differentiation of material properties allows the system to achieve comprehensive protection with minimal thickness by placing the right material property in the right location.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the elastic material is fixed in all areas to the smooth layer, then structural stability is improved, but the ability to absorb kinetic energy through relative movement is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidkinetic energy absorption capability
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent creates a dynamic protective system where the second protective layer (elastically stretchable material) can move relative to the first protective layer (smooth layer) during saw engagement. This relative movement is essential for the elastic layer to stretch and absorb kinetic energy. The structure maintains stability through its layered configuration while allowing necessary dynamic movement for energy absorption, achieving both stability and energy absorption capability.

Inventive Principle:
Principle #15Dynamics

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 system effectively slows down the saw by absorbing kinetic energy, providing simple and effective protection against cut injuries while maintaining flexibility and minimal hindrance to the user, allowing for efficient operation with reduced layer thickness.

Implementation Method 1

the elastically stretchable material of the second, outer protective layer slows down the movement of the hand saw. The teeth of the handsaw catch on the elastic material and are slowed down by the energy required to stretch the elastic material. The elastically stretchable material is stretched like a spring and thus exerts a kind of restoring force on the saw, which also slows the saw down.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2989915B1Cut protection
Publication Date: 2017.08.23 ANDREAS STIHL AG & CO KG
  • EP2989915B1 patent drawingFigure 1~3
  • EP2989915B1 patent drawingFigure 4~8

AI summary

A cut protection layer (1, 41, 61) has several protective layers (21, 22, 23, 51, 52, 71), wherein a first protective layer (21, 51, 71) has a smooth, slippery surface (26, 46) on at least one side (24). A second, outer protective layer (22) rests on the smooth, slippery surface (26, 46). The second protective layer (22) consists of an elastically stretchable material (27) and is displaceable relative to the first protective layer (21, 51, 71), at least in sections.