Elastomeric Valve Damping for Pneumatic Hammer Recoil Control

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Solution Overview

Problem

Existing percussive hammer devices, such as pneumatic percussion drills and rock breakers, suffer from inefficiencies due to elastic recoil of sliding spool valves, leading to poor pressure regulation and potential damage from misalignments and mis-positionings, which result in control and performance issues.

Innovation Solution

The use of energy damping materials or valve assemblies with internal damping to reduce the reflected velocity of the valve, dissipating compression stress waves and minimizing elastic recoil, thereby improving valve positioning control and reducing impact forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If standard valve materials (steel or high strength plastic) are used, then the valve is stiff and durable, but elastic recoil occurs during impact causing poor positioning control

Engineering Contradiction:

Improvevalve durabilityVSAvoidvalve positioning control

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent changes the material parameters of the valve from stiff standard materials (steel or high strength plastic) to elastomeric materials with specific durometer ranges (40-90 Shore A). This parameter change allows the valve to deform elastically during impact, absorbing recoil energy and maintaining positioning control while still providing durable service life.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material construction by combining elastomeric material with reinforcing structures or coatings. The valve body uses elastomeric material for shock absorption, while maintaining structural integrity through composite design, thus achieving both durability and positioning precision.

Inventive Principle:

Principle #40Composite materials

2Productivity

If the valve moves rapidly during reciprocation, then the device operates efficiently, but elastic recoil causes the valve to unintentionally cover or expose incorrect ports

Engineering Contradiction:

Improvedevice operating efficiencyVSAvoidport regulation accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the mechanical parameters of the valve by using elastomeric material with specific durometer ratings. This allows the valve to maintain rapid movement for efficiency while the material's elastic properties absorb recoil, preventing unintended port coverage and ensuring reliable port regulation throughout the reciprocation cycle.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful elastic recoil effect into a beneficial damping mechanism. The elastomeric material allows controlled elastic deformation during impact, transforming the harmful recoil that causes mispositioning into a beneficial energy absorption mechanism that maintains positioning accuracy while allowing rapid operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Speed

If the valve impacts position-limiting surfaces with high velocity, then the reciprocation cycle is maintained, but the impact causes elastic recoil and potential damage

Engineering Contradiction:

Improvevalve reciprocation speedVSAvoidimpact damage risk

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters of the valve from stiff materials to elastomeric materials with specific durometer ranges. This allows the valve to maintain high reciprocation speed while the elastomeric material absorbs impact energy through elastic deformation, significantly reducing the harmful impact forces and recoil that would otherwise cause damage or mispositioning.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements beforehand cushioning by using elastomeric material that is pre-configured to absorb impact energy. The material's inherent elastic properties provide built-in cushioning before impact occurs, preventing the harmful effects of high-velocity impacts while maintaining the reciprocation cycle integrity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 reduces elastic recoil, enhancing the efficiency and power of percussive drilling operations by improving valve control and reducing the risk of premature fatigue and breakage, leading to more precise and durable drilling performance.

Implementation Method 1

using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact

Methodology Applied

Scientific EffectEnergy damping: Damping

Implementation Method 2

using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact

Methodology Applied

Scientific EffectInternal damping: Damping

Data Source

PatentUS8176995B1Reduced-impact sliding pressure control valve for pneumatic hammer drill

Publication Date: 2012.05.15 NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA LLC

AI summary

A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.