Mobile Crane Outriggers for Torque-Free Stability

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Solution Overview

Problem

Crawler-mounted cranes face difficulties in uniformly distributing forces during operation on outriggers, leading to torque issues and material inefficiencies, as well as challenges in attaching and spacing outriggers effectively.

Innovation Solution

A crane design featuring a rotary joint connecting the superstructure to the undercarriage, with four outriggers oriented at 90° angles to each other, reducing torque and stress, and allowing for easier attachment and reduced material usage, including telescoping and tipping edge outriggers for enhanced stability and load handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If outriggers are attached to crawlers with non-perpendicular orientation, then the support base is enlarged, but torque is created in the middle section and crawlers leading to difficult force transmission and material inefficiency

Engineering Contradiction:

Improvesupport baseVSAvoidtorque

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The outriggers are oriented asymmetrically relative to the crawler axis, with specific outriggers positioned at right angles to the crawler while others are angled, creating a configuration that eliminates torque in the middle section while maintaining an enlarged support base

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

Instead of attaching all outriggers at the same orientation to the crawlers, the invention inverts the conventional approach by attaching outriggers at different orientations, with some perpendicular to the crawler and others at angles, thereby reversing the torque problem into a torque-free configuration

Inventive Principle:

Principle #13The other way round (Inversion)

2Area of stationary object

If outriggers are attached with slanted orientation, then the support base is enlarged, but attachment complexity and space occupation increase

Engineering Contradiction:

Improvesupport baseVSAvoidattachment ease

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

Different outriggers are attached with different orientations according to their specific positions and functions - some perpendicular to the crawler for easy attachment, others at angles to optimize support base coverage, creating local optimization rather than uniform attachment

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8499945B2Crane, in particular mobile crane with a narrow track and enlarged supporting base

Publication Date: 2013.08.06 TADANO DEMAG GMBH

AI summary

A mobile crane includes an undercarriage with a middle section and two parallel crawler carriages; a superstructure on which a boom is mounted, the superstructure being connected to the undercarriage by a rotary joint; two longitudinal outriggers connected to the undercarriage and extending in the longitudinal direction between the crawler carriages; and two transverse outriggers connected to the undercarriage and extending outside the crawler carriages. One of the longitudinal outriggers has an end with a transverse beam supported by spaced apart outrigger cylinders which provide an extended tipping edge to further stabilize the crane.