Ανάλυση εξαρτημάτων και λειτουργιών γερανογέφυρας: Ένας λεπτομερής οδηγός για την κατανόηση των βασικών εξαρτημάτων

If you want to understand the parts of an overhead crane, this guide is for you. It explains the main components, accessories, and assemblies of a typical overhead crane. Whether you are an operator, maintenance worker, or new to the industry, this article will help you understand the function and importance of each part for daily use, maintenance, and troubleshooting.

Overhead Crane Frame

Κύρια δοκός

The main girder is the core load-bearing structure of an overhead crane. It is usually made of high-strength steel and designed to resist bending and torsion, ensuring stability under heavy loads. Its main function is to support the trolley and hook, and to provide a track for the trolley to move smoothly along the girder for precise load positioning.

End Girder

The end girder connects both ends of the main girder and supports the entire crane structure. It is typically located on both sides of the crane and allows the whole system to travel along the runway rails. End girders are equipped with drive units or travel wheels and are connected to the crane traveling mechanism, ensuring stable movement along the track. Their design focuses on strength and durability under high loads, playing a key role in the overall stability and maneuverability of the crane.

Cabin

ο cabin is where the operator controls the crane. It is usually suspended below the main girder or placed in a position with a clear view of the working area. The cabin is designed for good visibility and safety. It is equipped with a control console or cam controller for precise lifting and movement operations. To ensure operator comfort, the cabin often includes air conditioning, ventilation, and an ergonomic seat and layout to reduce fatigue and improve safety and efficiency. Access to the cabin is typically provided via vertical or inclined ladders connected to the walkway.

Overhead Crane Traveling Mechanism

Τροχοί

Crane wheels are key components of the traveling mechanism, typically mounted on the bottom of the end girders. They run along the rails and support the entire weight of the crane. There are two main types: drive wheels, which propel the crane along the rails, and idle wheels, which assist in smooth movement. These wheels are usually made of high-strength alloy steel for wear and impact resistance under heavy loads and frequent movement. Their design considers rail wear and includes precise machining and adjustment to ensure smooth operation, low noise, and long service life for both the wheels and the rails.

Μοτέρ

The traveling motor powers the horizontal movement of the crane bridge and trolley along the rails. It converts electrical energy into mechanical motion, ensuring accurate and smooth travel. Typically coupled with a gearbox, the motor’s high-speed rotation is reduced to a lower speed with higher torque, providing sufficient traction and stability during crane movement.

Περιστέλλων

The reducer is a key transmission component between the motor and wheels. It reduces the high-speed output of the motor to a low-speed, high-torque output suitable for stable crane operation. Through multiple gear stages, it ensures sufficient pulling force for the crane to move smoothly along the rails. Made of high-strength, wear-resistant materials, the reducer is designed for long service life under frequent starts, stops, and varying loads. A precise gear ratio ensures smooth starting, stopping, and positioning.

Φρένο

ο brake is a critical safety device that ensures the crane stops reliably on the rails. It is typically mounted on the motor’s output shaft and functions through mechanical or electromagnetic force. When braking is required, it quickly applies force to stop the crane accurately and prevent uncontrolled movement caused by inertia. Made with wear-resistant materials, the brake is designed for heavy-duty and frequent start-stop conditions, often featuring overheat protection and automatic adjustment to maintain effective braking over long-term use.

Coupling

The coupling connects the motor to the gearbox or the gearbox to the wheels. It transmits torque and accommodates slight misalignments between connected shafts. In crane applications, couplings also absorb shocks and vibrations during operation, protecting transmission components and ensuring smoother power delivery.

Overhead Crane Hoisting Mechanism (Hoists and Trolleys)

In overhead cranes, common hoisting devices include hoists and open winch trolleys. Γερανοί μονής δοκού usually use hoists, while διπλοί γερανοί δοκών can choose either electric hoists or open winch trolleys.

Overhead crane hoists paired with trolleys are mounted on the main girder of the crane and can be used for vertical lifting and horizontal movement of loads. Common hoist types include manual chain hoists, wire rope electric hoists, and electric chain hoists. Electric hoists are suitable for high-efficiency and frequent operations, providing greater lifting force and faster working efficiency; manual hoists are used for light loads or precise operations, with simple operation and low maintenance costs. Wire rope electric hoists have faster speed and smoother, quieter operation, dominating the market for lifting capacities of 10 tons and above. Compared with wire rope electric hoists, electric chain hoists have more durable chains, take up less space, and are more affordable, usually used for light applications under 5 tons.

Open winch trolleys are installed between two main girders and use a pulley system and wire rope to lift objects. They are equipped with efficient motors and reducers, providing strong traction and stable lifting speed. Compared to traditional hoist-type lifting devices, open winch trolleys can handle heavier loads and higher lifting requirements.

The main components of an overhead crane hoisting mechanism include:

στάχυα

Sheaves are critical components in the hoisting mechanism used to guide the wire rope. By changing the direction and load-bearing capacity of the wire rope, sheaves effectively share the lifting load and enhance the crane’s lifting capability. There are two types of sheaves: fixed sheaves, which change the direction of the wire rope movement, and movable sheaves, which move with the load, thereby reducing the required pulling force.

The outer edge of a sheave is designed with a groove to firmly hold the wire rope and prevent slippage or wear. Multiple sheaves arranged in a block can multiply the crane’s load capacity while reducing the motor power required. Sheave blocks are key components for achieving efficient lifting operations.

Γάντζοι

Crane hooks are used for attaching and carrying loads, typically made of high-strength alloy steel and equipped with safety latches to prevent accidental load release during operation. Hooks are usually designed as single or double hooks; single hooks are suitable for light to medium loads, while double hooks help distribute heavier loads more evenly, improving stability and safety. Additionally, hooks can rotate 360 degrees, facilitating load handling from different angles and enhancing operational flexibility. Besides hooks, overhead cranes can also use other lifting attachments such as grab buckets and electromagnetic lifters depending on the application.

Κινητήρες

The hoisting motor is the core component providing lifting power. It is typically designed for high torque and low speed with high precision, to meet the demands of lifting and lowering heavy loads. The motor must deliver strong starting torque to enable smooth startup under load and sufficient lifting force. Motors often feature variable frequency drives or speed control systems, allowing operators to precisely control lifting speed, improving positioning accuracy and operational flexibility.

Reducers

The reducer connects the motor and the drum, serving as a crucial transmission component. Its main function is to convert the high-speed rotation of the motor into low-speed, high-torque output suitable for lifting heavy loads, ensuring smooth and accurate load hoisting. Reducers typically use multi-stage gear transmission, progressively reducing speed while increasing torque to provide the necessary power during lifting operations.

Φρένα

Brakes in the hoisting mechanism control and hold the load during lifting or lowering, preventing uncontrolled load descent. They are usually installed on the motor or reducer output shaft. When lifting stops or in emergency situations, the brake quickly applies force to keep the load stable in position, ensuring operational safety.

Drums

ο τύμπανο σχοινιού γερανού is the component around which the wire rope is wound and unwound, controlling the vertical movement of the hook or other lifting attachments. The drum surface has grooves to keep the wire rope neatly aligned during winding, preventing slippage or overlap, which helps extend the wire rope’s service life and reduce wear.

Drums are connected to motors through reducers for precise lifting control. Their dimensions, groove depth, and pitch are optimized based on the wire rope specifications and crane design load. Drums also include rope guides to maintain orderly winding and prevent tangling. Proper design and maintenance of the drum are critical for smooth crane operation and safe lifting.

Wire Ropes

Wire ropes are essential components that bear and lift loads in the hoisting mechanism. They connect the hook, sheave block, and drum, enabling lifting and lowering by winding on the drum. Wire ropes vary in diameter, tensile strength, and corrosion resistance depending on the crane’s application—outdoor cranes may use corrosion-resistant ropes. Wear, broken strands, and deformation affect wire rope safety, so regular inspection and maintenance are necessary to ensure safe and reliable lifting operations.

Overhead Crane Electrical and Control Systems

The electrical control system is relatively complex and mainly consists of the following parts:

Busbar

The busbar is the main power supply method for overhead cranes. It is usually installed on one side of the crane runway and consists of a series of parallel conductive rails made of copper or aluminum. The busbar supplies power continuously to the bridge and trolley as they move, ensuring all electrical devices operate without interruption.

The busbar system includes rails, collectors, and insulating brackets. Collectors are installed on the bridge or trolley, sliding along the busbar to collect electricity and transmit it to the crane’s motors and control devices. Insulating brackets fix the busbar in place and isolate it from the structure to prevent leakage and ensure safety.

Precise alignment is required in busbar design and installation to avoid poor contact or jumping of the collectors, which could affect power stability.

Power Supply Cable

The power supply καλώδιο mainly provides stable electricity to the crane’s electric hoist or winch trolley, driving system, and control system. The cables are usually arranged on the crane’s framework or trolley, guided by sliding rails or cable carriers, allowing the cables to move freely with the bridge or trolley without being pulled or damaged during operation.

Control

Overhead cranes can use various control methods. The main types include operator cabin control, remote control, and pendant control:

• Operator Cabin Control: An independent cabin is installed on the crane, usually suspended under the main beam or near the trolley. The operator controls all crane functions (bridge travel, trolley travel, and hoisting) from inside via control consoles and cam controllers. The cabin provides a good view of the lifting area, allowing precise control. This method suits complex, high-load lifting tasks and ensures safety and accuracy.
• Remote Control: Uses wireless radio signals, allowing the operator to control the crane from the ground with a handheld remote. This method offers great flexibility and allows operation from a safe distance, ideal for limited visibility or hazardous environments. Functions typically include start, stop, speed up, slow down, and hoist up/down, enhancing safety and convenience.
• Pendant Control: A wired control method where the operator uses a control box (pendant) hanging near the crane or hoisting equipment. The pendant has multiple buttons for basic movements such as hoisting, lowering, forward, and backward. It suits short-distance moves and simple operations, offering ease of use and versatility. Pendant control allows the operator to closely observe the load and directly control the equipment, suitable for precise lifting tasks.

Overhead Crane Rail System

Ράγες

Rails are key components supporting the smooth movement of a bridge crane, usually installed on load-bearing beams on both sides of the building. Made of high-strength steel, rails offer good wear and impact resistance to bear the crane and its load. Common types include steel rails and I-beams, chosen based on load and environment. Precise alignment during installation ensures stable crane movement without deviation or vibration. Regular checks for parallelism, wear, and fastening are essential, with cleaning, lubrication, or replacement as needed to extend service life. Accurate rail installation and maintenance are vital for safe and efficient crane operation.

Δοκός διαδρόμου

The runway beam supports the crane rails and operation, typically mounted on building columns or independent supports. It must have sufficient strength and rigidity to bear the crane’s weight, load, and dynamic forces during movement. The beam provides a stable path, ensuring smooth crane travel. Usually made of high-strength steel or concrete, it is precisely aligned and fixed to maintain level and straight rails, preventing instability from bending or uneven settling. Proper design, installation, and maintenance of the runway beam are fundamental for safe and reliable crane operation.

Overhead Crane Safety Protection Devices

Safety protection devices on bridge cranes are crucial for ensuring safe equipment operation, protecting operators, and preventing damage. Common safety devices and their functions include:

• Emergency Power Off Switch: Quickly cuts off the crane’s main power and control circuits in emergencies, usually located in the distribution cabinet.
• Warning Bell: Provides work alerts through a foot switch.
• Overload Load Limiter: Installed on the lifting mechanism; alarms when the load reaches 90% of the rated capacity and automatically cuts power at 105% overload.
• Upper Limit Position Protection: A limit device on the lifting mechanism that automatically cuts power when the hook reaches its upper limit.
• Travel Limit Switch: Installed on both sides of the bridge and trolley travel mechanisms; cuts power when reaching travel limits and allows reverse movement.
• Lighting: Ensures safe operation in low-light environments (e.g., nighttime or indoors) by providing adequate visibility for operators and safety for the surrounding area.
• Buffer: A safety device installed at the end of the crane’s metal structure that absorbs collision energy to reduce impact.

We Are Overhead Crane Parts Suppliers

Ensuring every component of a bridge crane works stably and efficiently is essential, as each directly impacts performance and safety. As professional bridge crane manufacturers, we provide a wide range of high-quality crane parts. Whether ηλεκτρικά ανυψωτικά, winches, bridge girders, rails, or custom parts, we offer the best solutions tailored to your needs!

Η Σίντι

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