Overhead crane components and functions

In the bustling world of manufacturing, armazéns, canteiros de obras, and ports, overhead cranes stand as indispensable workhorses. These heavy-duty machines streamline material handling, lift massive loads, and enhance operational efficiency. But have you ever wondered what makes these cranes so reliable and versatile? The answer lies in their well-designed components, each playing a unique and critical role. Neste blog, we’ll break down the key ponte rolante components and their essential functions, helping you gain a deeper understanding of how these industrial giants operate.

Overhead Crane Parts

Viga da ponte (Main Beam)

The bridge girder, often referred to as the main beam, is the backbone of an overhead crane. It’s the horizontal structure that spans the width of the workspace (Por exemplo, between two crane runways) and bears the weight of the load, carrinho, and other components.

Functions:

• 1. Primary load-bearing component: Distributes the weight of the lifted load evenly across the crane’s runways, evitando danos estruturais.
• 2. Provides a stable track for the trolley to move horizontally (along the length of the bridge).
• 3. Ensures structural integrity during operation, even under heavy or dynamic loads.

Bridge girders are typically made of high-strength steel to withstand extreme loads. Common designs include single-girder (for lighter loads) and double-girder (for heavier, more demanding applications) configurations.

Caminhões finais (End Carriages)

End trucks are mounted at both ends of the bridge girder. They house the overhead crane wheels, axles, and drive mechanisms that enable the entire crane to move along the runway rails installed on the building’s walls or columns.

Functions:

• 1. Supports the bridge girder and transfers its load to the runway rails.
• 2. Enables longitudinal movement (viajando) of the crane along the runway, allowing coverage of the entire length of the workspace.
• 3. Contains braking systems to ensure precise stopping and prevent unintended movement, enhancing safety.

The design of end trucks varies based on the crane’s capacity and speed requirements. Some end trucks use motorized drives for automated movement, while others may be manually operated for lighter-duty cranes.

Carrinho

The trolley is a movable unit that travels along the top or bottom of the bridge girder. It carries the hoisting mechanism (the part that lifts the load) and allows for lateral movement (side-to-side) of the load within the crane’s coverage area.

Functions:

• 1. Supports and moves the hoisting mechanism horizontally across the bridge girder.
• 2. Enables precise positioning of the load, which is crucial for tasks like loading/unloading trucks, placing materials on assembly lines, or stacking goods in warehouses.
• 3. May be equipped with its own drive system (motorized trolley) for smooth and controlled movement, or manually pushed for smaller cranes.

Trolleys are classified into different types, such as top-running (travels on top of the bridge girder) and under-running (travels beneath the bridge girder), depending on the crane’s design and application.

Mecanismo de elevação

O mecanismo de elevação é o coração da ponte rolante, responsible for lifting and lowering the load. It consists of several sub-components, including a motor, caixa de velocidades, tambor de cabo de aço de guindaste, cabo de aço ou corrente, ganchos, e freios.

Functions:

• 1. Lifts and lowers the load using wire ropes or chains wound around a drum. The motor drives the gearbox, which rotates the drum to raise or lower the load.
• 2. Controls the speed of lifting/lowering to ensure smooth operation and prevent load swing.
• 3. Uses brakes (mechanical or electromagnetic) to hold the load in place when it’s not being lifted or lowered, preventing accidental drops and ensuring safety.

The capacity of the hoisting mechanism determines the maximum load the crane can lift. Por exemplo, a crane with a 10-ton hoisting mechanism can safely lift loads up to 10 toneladas.

Gancho de guindaste

O gancho de guindaste is the component that directly attaches to the load. It’s suspended from the hoisting mechanism via wire ropes or chains and comes in various designs to accommodate different types of loads.

Functions:

• 1. Provides a secure attachment point for the load, using latches or safety catches to prevent the load from slipping off during lifting.
• 2. Distributes the load’s weight evenly to the hoisting ropes/chains, ensuring stable lifting.
• 3. May be customized for specific applications (Por exemplo, hook blocks for multiple-part rope systems, or specialized hooks for lifting containers or coils).

Crane hooks are made of high-strength alloy steel to withstand heavy loads and are regularly inspected for wear, rachaduras, or deformation to ensure safety.

Operator Cab (or Control Pendant/Radio Remote)

The operator cab is the control center of the overhead crane, where the operator sits to manipulate the crane’s movements. For smaller cranes or those used in tight spaces, control pendants (handheld push-button controls) or radio remote controls are often used instead.

Functions:

• 1. Allows the operator to control all crane movements: lifting/lowering the load, moving the trolley, and traveling the crane along the runway.
• 2. Provides the operator with a clear view of the load and the surrounding workspace, ensuring safe and precise operation.
• 3. May be equipped with safety features such as emergency stop buttons, load indicators, and alarms to alert the operator of potential hazards.

Radio remote controls offer added flexibility, allowing the operator to stand in the optimal position to monitor the load without being confined to the cab.

Sistema Elétrico

The electrical system powers and controls all the crane’s components, including the hoisting motor, trolley motor, travel motors, freios, e sistemas de controle. It consists of a power supply, motores, inverters, controllers, cabos, e dispositivos de segurança.

Functions:

• 1. Supplies electrical power to the motors, enabling the crane’s movements.
• 2. Controls the speed and direction of the motors, ensuring smooth and precise operation.
• 3. Incorporates safety devices (Por exemplo, overload protectors, interruptores de limite) to prevent electrical faults and overloads, which could damage the crane or cause accidents.

Modern overhead cranes often use variable frequency drives (Inversores de frequência) in their electrical systems to optimize energy efficiency and improve control over movement speed.

Trilhos de pista

While not always considered part of the crane itself, runway rails are essential for the crane’s operation. They are installed along the length of the workspace (usually on the building’s columns or support structures) and provide a track for the crane’s end trucks to travel on.

Functions:

• 1. Guides the crane’s movement along the length of the workspace, ensuring stable and straight travel.
• 2. Supports the weight of the entire crane and the lifted load, transferring it to the building’s structural supports.

Runway rails must be properly aligned and leveled to prevent excessive wear on the crane’s wheels and ensure safe operation.

Conclusão: The Synergy of Components

An overhead crane’s performance relies on the seamless collaboration of all its components. From the bridge girder (the backbone) to the hoisting mechanism (the heart) and the operator cab (the brain), each part plays a vital role in ensuring safe, eficiente, and reliable material handling. Understanding these components and their functions is not only useful for crane operators and maintenance teams but also for business owners looking to invest in or optimize their material handling equipment.

Whether you’re operating a small single-girder crane in a workshop or a large double-girder crane in a port, proper maintenance of each component is key to extending the crane’s lifespan and ensuring workplace safety. Inspeções regulares, lubrificação, and repairs will keep your overhead crane running smoothly for years to come.

Have questions about overhead crane components or need advice on choosing the right crane for your application? Feel free to leave a comment below!