Flexible Piston Rod Shield for Hydraulic Cylinder Impact Protection

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Solution Overview

Problem

Piston rods of hydraulic excavator backhoe bucket cylinders are prone to damage due to their exposed position, leading to costly downtime and maintenance, and existing protection methods like metal channel boxes are either ineffective or require frequent replacement and can cause further damage.

Innovation Solution

A non-metallic flexible piston rod shield made of materials like high-density polyethylene (HDPE) or polyvinyl chloride (PVC), which deforms upon impact and returns to its original shape, providing protection for the piston rod and sliding through a guide fixed to the barrel cap, with a barrel shield allowing hydraulic hose space and a shock absorber insert for additional support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal channel boxes are used to protect piston rods, then protection against damage is improved, but the protection system itself becomes prone to damage requiring continual maintenance and replacement

Engineering Contradiction:

Improveprotection effectivenessVSAvoidmaintenance frequency

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent applies a flexible plastic shield instead of rigid metal channel boxes. The shield is made from flexible plastic material that can deform under impact forces and return to its original shape, providing continuous protection without requiring maintenance or replacement. This resolves the contradiction by maintaining reliable protection while eliminating the maintenance issues associated with metal channels.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the material parameter from rigid metal to flexible plastic. This parameter change allows the protection system to absorb impacts through elastic deformation rather than rigid resistance, preventing damage to both the piston rod and the protection system itself, thereby reducing maintenance requirements while maintaining protection effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If metal channel boxes are used to protect piston rods, then protection is provided, but the channels may themselves damage the piston rod if sufficiently deformed

Engineering Contradiction:

Improveprotection effectivenessVSAvoidrod damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The flexible plastic shield can deform under impact without transferring damaging forces to the piston rod. Unlike rigid metal channels that may deform and scratch or damage the rod surface, the flexible material absorbs impact energy through elastic deformation, maintaining rod surface integrity while providing continuous protection.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent converts the harmful rigid impact resistance of metal channels into beneficial elastic energy absorption. The flexible plastic material transforms impact energy into temporary deformation, then releases it as the material returns to its original shape, protecting both the rod and the shield from damage.

Inventive Principle:

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

3Strength

If a rigid protection system is used, then structural strength is improved, but the system cannot deform to absorb impact energy from falling rocks

Engineering Contradiction:

Improvestructural strengthVSAvoidimpact damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the mechanical property parameter from rigid to flexible. The flexible plastic shield maintains sufficient structural strength to protect the piston rod while being able to deform under impact loads from falling rocks. This resolves the contradiction by providing both strength and impact absorption capability through material selection.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The flexible plastic shield acts as a beforehand cushioning element that deforms to absorb impact energy before it can reach the piston rod. The material's inherent elasticity provides built-in shock absorption, protecting the rod from damage without requiring additional cushioning mechanisms.

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 flexible piston rod shield effectively protects the piston rod from damage, including impacts from large objects like rocks, and maintains functionality with repeated blows, reducing maintenance costs and downtime by withstanding deformation without compromising the smooth surface of the piston rod.

Implementation Method 1

the non-metallic flexible piston rod shield is able to deform and protect the smooth surface of the piston rod even if coming into contact with the piston rod. The flexible piston rod shield thereafter returns to shape to withstand repeated blows.

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4048917B1A hydraulic cylinder piston rod protection system

Publication Date: 2024.09.25 CHROMEGUARD PTY LTD

Figure 1A~1B
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AI summary

A protection system for a hydraulic cylinder piston having a barrel and a piston rod reciprocating therein, the protection system comprising a piston rod shield which is fixed with respect to the piston rod in use to move with respect to the barrel to cover the piston rod when the piston rod is exposed from the barrel and wherein the piston rod shield comprises a non-metallic flexible material which substantially returns to shape after deformation.