Rubber tyred gantry cranes (RTG cranes) have become an essential lifting solution across a wide range of industries, including shipping container terminals, precast concrete yards, steel processing plants, and construction material storage sites. Their mobility, flexibility, and adaptability make them a preferred choice for operations that require efficient and flexible material handling without fixed rail infrastructure.

A critical component that defines the performance, safety, and versatility of RTG cranes is the lifting mechanism. The lifting mechanism is responsible for raising, lowering, and accurately positioning loads of various sizes and weights. This article explores the different types of lifting mechanisms used in rubber tyred gantry cranes, how they work, their advantages, and how to choose the right type based on application needs.

The lifting mechanism in an RTG crane generally consists of the hoisting winch, wire rope or chain system, motor drive, and load-handling device (such as a hook, spreader beam, or specialized attachment). It forms the core system that enables the crane to lift and lower loads safely and effectively.

Depending on the application and design, lifting mechanisms in RTG cranes can be categorized based on:

Drive type (Electric or Hydraulic)

Load handling device (Hook, Spreader, Beam)

Hoist configuration (Single or Twin hoist)

Control system (Manual, Semi-automatic, Automatic)

Let’s dive deeper into each of these classifications.

Electric Lifting Mechanism

How it works:

Electric lifting mechanisms use an electric motor to drive the hoist. The motor powers a drum around which wire rope is wound. As the drum rotates, the rope lifts or lowers the load attached to it.

Features:

Powered by diesel generators or electric power cables (in electric RTG cranes)

Common in container handling and light to medium-duty lifting

Paired with Variable Frequency Drives (VFDs) for precise control

Suitable for automatic and semi-automatic operation modes

Advantages:

Energy-efficient: Especially when connected to a grid or hybrid power system

Low noise: Compared to hydraulic systems

Precision control: Smooth acceleration and deceleration

Applications:

Container yards

Indoor/outdoor warehouses

Precast concrete manufacturing

Hydraulic Lifting Mechanism

How it works:

Hydraulic lifting mechanisms use pressurized hydraulic fluid to drive pistons or hydraulic motors that in turn power the hoist system. These systems are usually powered by a diesel engine with a hydraulic pump.

Features:

More robust for heavy-duty lifting

Preferred where high torque is needed at low speeds

Simpler in structure for some specific lifting configurations

Advantages:

High lifting power in compact form

Stable performance in rugged environments

Better overload tolerance

Applications:

Steel and heavy machinery yards

Off-road or uneven terrain operations

Shipyards

Hoisting Winch System

Winch-Based Hoisting:

Most RTG mobile gantry cranes use a winch-based system where a large drum winds or unwinds steel wire rope. This system can be single-drum or twin-drum based on the load requirement and redundancy.

Key Elements:

Hoisting motor (electric or hydraulic)

Gearbox for torque control

Wire rope drum

Limit switches for top and bottom positions

Benefits:

High load capacity

Long lifting height capability

Precise control with VFD integration

Chain Hoist Mechanism (Less Common in RTGs)

While rare, some smaller rubber tyred gantry cranes for light loads may utilize chain hoists instead of wire rope systems. These are typically used in compact environments or for lifting small components.

Advantages:

Lower cost

Simple maintenance

Compact size

Limitations:

Limited lifting height

Lower lifting speed and capacity

Load Handling Devices

The lifting mechanism is only as effective as the load handling device it is connected to. RTG cranes can be fitted with various attachments depending on the lifting application:

a) Hook

The most versatile and widely used attachment

Suitable for general lifting tasks like steel coils, construction materials, machinery

b) Spreader Beam

Used in container handling operations

Adjustable spreaders for 20ft, 40ft, and 45ft containers

Locking twistlocks ensure secure container lifting

c) Custom Lifting Beams and Slings

Designed for precast concrete segments, large pipes, or non-standard loads

Often used with dual hoisting mechanisms for load balance

Single vs. Twin Hoisting Mechanisms

RTG cranes can be equipped with one or two hoisting mechanisms depending on lifting needs.

Single Hoist

Suitable for symmetrical loads

Simpler control system

Lower cost

Twin Hoist (Synchronous Lifting)

Ideal for long or asymmetrical loads

Both hoists can lift simultaneously or independently

Used in beam lifting, bridge construction, and heavy industrial applications

Anti-Sway Control in Lifting Mechanisms

One of the modern innovations in RTG crane lifting mechanisms is the integration of anti-sway technology. This feature reduces load swing during lifting and movement, significantly improving safety and positioning accuracy.

Methods:

Active anti-sway via sensors and control algorithms

Passive anti-sway using dampers or pendulum-restricting systems

The lifting mechanism is a fundamental aspect of rubber tyred gantry cranes that determines their lifting performance, adaptability, and safety. Whether it’s a high-torque hydraulic hoist for heavy-duty construction or a precision electric winch system for container handling, the right choice of lifting mechanism can maximize operational efficiency and reduce risk.

With advancements in smart control systems, anti-sway technology, and eco-friendly power options, modern RTG cranes are becoming more intelligent, energy-efficient, and application-specific than ever before. Understanding the types of lifting mechanisms available and their respective benefits allows users to make informed decisions that align with their operational goals and budget.