Rotating Cylinder Guard Layout for Demolition Tool Arms

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Solution Overview

Problem

Existing cylinder guards for construction machines, such as those used in demolition work, suffer from increased parts and mounting operations, leading to higher costs and potential interference with building structures due to fragments biting into sliding portions during demolition.

Innovation Solution

A single-piece cylinder guard that rotates in synchronization with the working tool cylinder, interposed between the tool and cylinder, protecting the cylinder by being fixed to a link and covering its lower surface, thus preventing fragments from hitting it during demolition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cylinder guard with tube-side guard and rod-side guard connected by sliding mechanism is used, then the working tool cylinder is covered throughout the entire stroke, but fragments bite into the sliding portion causing rough slide motion and increased parts complexity

Engineering Contradiction:

Improveprotection of working tool cylinderVSAvoidnumber of parts and mounting operations

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the tube-side guard and rod-side guard into a single integrated cylinder guard structure. The guard is formed as one piece with a body portion covering the tube side and a cap portion covering the rod side, eliminating the sliding connection between separate guards. This merging reduces the number of parts and mounting operations while maintaining comprehensive protection of the working tool cylinder throughout its stroke.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cylinder guard is segmented into functional portions (body portion and cap portion) that are integrally formed. The body portion covers the tube side of the cylinder and the cap portion covers the rod side, with an opening provided for the rod to pass through. This segmentation allows the guard to protect the cylinder throughout its entire stroke while avoiding the need for sliding mechanisms between separate guards.

Inventive Principle:

Principle #1Segmentation

2Length of moving object

If working tool cylinder is disposed on upper surface side of arm, then maximum ground height is achieved, but cylinder interferes with ceilings and reinforcing bars during demolition

Engineering Contradiction:

Improveground height of working toolVSAvoidinterference with building structures

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional arrangement by disposing the working tool cylinder on the lower surface side of the arm instead of the upper surface side. This inversion allows the working tool to achieve maximum ground height for demolition work while the cylinder remains positioned below the arm, preventing interference with ceilings and reinforcing bars of buildings being demolished.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12534869B2Construction machine

Publication Date: 2026.01.27 HITACHI CONSTRUCTION MACHINERY CO LTD

AI summary

A working mechanism (8) includes a lower boom (9), an upper boom (10), a middle arm (11), an arm (12), a working tool (13), a working tool cylinder (22), and a link (16). The working tool cylinder (22) is disposed on a lower surface (12B) side of the arm (12), and a cylinder guard (23) is fixed on a first link (17) of the link (16). The cylinder guard (23) is rotationally displaced in synchronization with an expanding or contracting operation of the working tool cylinder (22) and is interposed between the working tool (13) and the working tool cylinder (22) to protect the working tool cylinder (22).