Electric Linear Drive for Telescopic Crane Locking

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Solution Overview

Problem

Hydraulic systems for actuating locking bolts in telescopic crane booms require extensive space, weight, and assembly effort, and are susceptible to external influences like temperature and line length variations, necessitating additional electrical control lines for valve actuation, leading to increased costs and maintenance needs.

Innovation Solution

An electric linear drive with an integrated sensor system and mechanical self-locking capability, connected to a control unit via a cable, which uses existing electrical energy and eliminates the need for a separate hydraulic unit, allowing for compact and low-maintenance operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydraulic drive is used to actuate locking bolts, then the locking function can be achieved, but hydraulic lines and control valves are required which increase space, weight, assembly effort, and system complexity

Engineering Contradiction:
Improvelocking functionVSAvoidhydraulic system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the hydraulic drive system with an electric linear drive. The electric motor with integrated gear mechanism directly actuates the locking bolt through a cable connection, eliminating the need for hydraulic lines, pumps, and control valves. This substitution reduces system complexity while maintaining the locking function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the hydraulic system components (hydraulic lines, pump, control valves) from the telescopic boom structure. By eliminating these components and replacing them with a compact electric linear drive, the space and weight requirements are significantly reduced while the locking function remains intact.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If hydraulic lines are routed to the locking system, then the locking function can be controlled, but temperature and line length variations affect pressure build-up, reducing reliability

Engineering Contradiction:
Improvelocking controlVSAvoidtemperature and line length influence
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the hydraulic pressure-based control system with an electric linear drive that uses electrical energy to directly position the locking bolt. This eliminates the pressure build-up issues caused by temperature and line length variations, as the electric motor provides consistent force regardless of environmental conditions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electric linear drive with integrated sensor system automatically detects the position of the locking bolt and adjusts its operation accordingly. The system self-regulates to achieve precise positioning without requiring external pressure regulation mechanisms that are sensitive to environmental factors.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If valves are actuated to control locking, then locking control is achieved, but additional electrical lines must be laid, increasing assembly effort and cost

Engineering Contradiction:
Improvelocking controlVSAvoidassembly effort
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent removes the intermediate control valves from the system architecture. The electric linear drive is controlled directly through a single cable connection that carries both power and control signals, eliminating the need for additional electrical lines that would be required to actuate multiple valves in a hydraulic system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the power supply and control functions into a single cable connection for the electric linear drive. This integrated approach eliminates the need for separate control wiring that would be required for valve actuation in hydraulic systems, reducing assembly complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

4Force

If a hydraulic unit is used for the locking system, then sufficient force can be provided, but space and weight requirements increase

Engineering Contradiction:
Improvelocking forceVSAvoidlocking system weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent replaces the heavy hydraulic unit with a compact electric linear drive that uses a high-torque motor with integrated gear mechanism. This electric system provides sufficient locking force through direct mechanical advantage from the gear reduction, achieving the same force output with significantly reduced weight and volume.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electric linear drive uses a high-torque motor with gear mechanism to dynamically generate the required locking force only when needed, rather than requiring a continuously pressurized hydraulic system. This dynamic force generation allows for a much lighter overall system design while maintaining adequate locking capability.

Inventive Principle:
Principle #15Dynamics

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 provides a compact, low-maintenance locking system for telescopic sections of mobile cranes that is less affected by external influences, reducing space and weight requirements while maintaining reliable operation without the need for hydraulic lines.

Implementation Method 1

the sliding link being drivable with an electric linear drive

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 2

the electric linear drive is provided with mechanical self-locking, or that the electric linear drive is provided with a holding brake, and that the mechanical self-locking or holding brake can hold a respective position of the linear drive without applying electrical energy

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2871149B1Drive for a slide of a locking system of a telescopic system of a crane arm
Publication Date: 2017.06.21 TEREX GLOBAL GMBH
  • EP2871149B1 patent drawingFigure 1
  • EP2871149B1 patent drawingFigure 2
  • EP2871149B1 patent drawingFigure 3

AI summary

The invention relates to the drive of a sliding cam of a locking system of a telescopic system, comprising a telescopic cylinder (1) with an outer telescopic section (2, 3) and an inner telescopic section (6, 7), each of which is provided with a locking hole (5) into which a locking bolt (11) can be releasably inserted and withdrawn via a sliding cam (14) provided with a cam track (12) and a gripper (10), wherein the locking bolt (11) is designed to be movable by means of a driver (9) running in the cam track (12) such that the locking bolt (11) performs a linear movement and the extension sections (3, 6) can be connected to each other by inserting the locking bolt (11) into the bolt hole (5) and the sliding cam (14) can be driven by an electric linear drive (4).