Conical Spring Percussion Tool Vibration Control

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Solution Overview

Problem

Existing fluid-powered percussion tools face challenges with overload resistance and vibration-induced injuries due to inadequate design of the elastically resilient element and pressurized fluid connection, particularly in handling extreme loads and maintaining low vibration levels.

Innovation Solution

The introduction of a conical helical spring as the elastically resilient element and a flexible PVC plastic hose with polyester reinforcement for the pressurized fluid connection, which provides enhanced compression ability, radial stiffness, and reduced vibration, allowing for secure radial fixation and improved operational stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a straight helical spring is used as the elastically resilient element, then the spring can provide axial rigidity, but it cannot allow extreme compression due to closed-up spring turns

Engineering Contradiction:
Improveaxial rigidityVSAvoidcompression ability
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The patent applies a conical spring geometry instead of a straight cylindrical spring. The conical shape with varying diameter along the axis allows the spring to accommodate extreme compression while maintaining structural integrity. The larger base diameter provides stability and the tapered form allows gradual coil closure without binding

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spring parameters are optimized with a specific cone angle (15-45 degrees), wire diameter (5-20% of base diameter), and pitch ratio to balance axial rigidity with compression capability. The geometric parameters are carefully selected to ensure the spring can deflect up to 80% of its free length while maintaining sufficient stiffness

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a nonflexible connection for pressurised fluid is used, then the percussion tool can move in linear fashion, but the connection cannot handle extreme overloads

Engineering Contradiction:
Improvelinear movement stabilityVSAvoidoverload resistance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent employs a flexible hose with polyester reinforcement instead of a rigid pipe for pressurised fluid delivery. The hose maintains sufficient structural integrity to guide fluid flow while its flexibility allows it to accommodate the percussion tool's movement and absorb extreme overloads without breaking

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The fluid connection uses a composite structure combining flexible PVC plastic with polyester reinforcement layers. This composite construction provides both the flexibility needed for movement and the strength required to handle extreme pressure overloads

Inventive Principle:
Principle #40Composite materials

3Device complexity

If a rubber membrane is used as the elastically resilient element, then the connection can be integrated, but the element has unacceptable lifetime when exposed to extreme overloads

Engineering Contradiction:
Improveintegration simplicityVSAvoidlifetime under overload
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent extracts the pressurised fluid connection from the elastically resilient element, separating these two functions. The conical spring provides purely mechanical resilience while the flexible hose handles fluid delivery, allowing each component to be optimized for its specific function and both to withstand extreme overloads

Inventive Principle:
Principle #2Taking out (Extraction)

4Strength

If the spring turns are closed up during compression, then the spring can provide rigidity, but the possible compression is limited

Engineering Contradiction:
Improvespring rigidityVSAvoidcompression range
Core Design Contradiction:
StrengthVSDuration of action of moving object

Solution Approach 1:

The conical geometry with its tapered form prevents spring turns from closing up completely during compression. The varying diameter creates a progressive coil closure pattern that maintains gaps between adjacent turns even under extreme compression, enabling deflection up to 80% of free length while maintaining rigidity

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 significantly increases the tool's resistance to overloads and extends its lifespan while minimizing operator exposure to vibrations, ensuring effective operation with reduced risk of injury and improved performance in demolition tasks.

Implementation Method 1

an elastically resilient element with an integrated line for pressurised fluid arranged to load the percussion mechanism against a neutral position in the tool housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a flexible connection for pressurised fluid... arranged to load the percussion mechanism against a neutral position

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP2265417B1Fluid powered percussion tool
Publication Date: 2018.04.04 ATLAS COPCO AIRPOWER NV
  • EP2265417B1 patent drawingFigure 1
  • EP2265417B1 patent drawingFigure 2

AI summary

Fluid-powered percussion tool 1, comprising a housing 2 with a supply channel for pressurised fluid 3, a percussion mechanism 4, a swinging joint 5 arranged to carry the percussion mechanism 4 relative to the housing 2 at a point situated between the forward end A and the rear end B of the percussion mechanism 4, at least one elastically resilient element 6 arranged between the housing 2 and the percussion mechanism 4 at a distance from the swinging joint 5 and arranged to load the percussion mechanism 4 against a neutral position in the housing 2 and to absorb the vibrational movements of the percussion mechanism 4, and a flexible connection for pressurised fluid 7 for distribution of pressurised fluid from the supply channel for pressurised fluid 3 to the percussion mechanism 4. The elastically resilient element 6 comprises a conical spring 8. The flexible connection for pressurised fluid 7 comprises a hose 11.