Name: QZ Grab Bucket Overhead Crane (QZ型抓斗桥式起重机)
Brand: Weihua
Availability: InStock

Product Overview

A QZ Grab Overhead Crane is a double girder overhead crane fitted with a grab bucket for bulk material handling. It is commonly used for coal, ore, limestone, scrap, sand, clinker, and other loose materials in steel plants, ports, power stations, cement plants, and waste treatment facilities.

The crane uses a four-rope grab bucket to pick up, transport, and discharge bulk materials. Grab bucket type, lifting capacity, span, lifting height, working duty, and control method are selected according to the material characteristics and site conditions. Different configurations are available for indoor, outdoor, and automated handling systems.

Tipos

Peças

Especificações

QZ Grab Overhead Cranes are divided into single girder and double girder types. Single girder cranes are commonly used for light-duty bulk material handling with smaller grab capacities. Double girder cranes are used for larger grab buckets, higher lifting capacities, and continuous operation in steel plants, mines, power stations, and other heavy industrial facilities. Grab bucket type, span, lifting height, and control method are selected according to the material and operating conditions.

Single Girder Grab Overhead Crane

The main girder is a single box-type or I-beam structure. The structure is relatively simple and the manufacturing cost is lower. It is used in applications with lower lifting capacity, shorter span, and limited space requirements, such as small warehouses or workshops.

Rated Capacity: 1–20 t
Span: 3–30 m
Lifting Height: 6–24 m
Duty Class: A3

Double-girder Grab Bridge Crane

This is the most common standard QZ-type crane. It uses two parallel main girders with a rigid structure and high stiffness. It handles larger load capacities and spans, with stable operation. It is widely used in heavy industry sectors such as ports, power plants, steel mills, and cement plants for bulk material loading and unloading.

Rated Capacity: 20–320 t
Span: ≤31.5 m (customizable)
Lifting Height: 6–30 m+
Duty Class: A6–A8

Peças

The QZ Grab Overhead Crane consists of the bridge frame, trolley, grab bucket, traveling mechanism, hoisting and opening-closing mechanism, electrical system, and safety and auxiliary devices.

- Bridge Frame: Main steel structure of the crane, usually double girder box type (single girder also available). Carries the full load and moves along the workshop runway, defining span and capacity.

- Trolley: Moves along the bridge girder. Integrates hoisting and traveling units and drives the grab bucket lifting, opening, and closing.

- Grab Bucket: Handles bulk materials such as coal, ore, and grain. Types include rope grab and electric grab, selected based on material conditions.

- Traveling Mechanism: Includes crane traveling and trolley traveling. The crane runs along the runway; the trolley runs along the girder.

- Hoisting and Opening-Closing Mechanism: Two independent hoist systems. One controls lifting, the other controls the grab opening and closing.

- Electrical System: Includes motors, control system, and power supply units. Provides power and control for all movements.

- Safety and Auxiliary Devices include limit switches, emergency stop, alarms, and operator cabin or ground control station.

QZ Grab Overhead Crane: each part works together for bulk material handling in ports, steel plants, power plants, and similar industrial sites.

To learn more about the functions of safety devices, read the article: “Overhead Crane Safety Devices: Types, Functions, and Working Principles”

Especificações

QZ Grab Overhead Crane is used for bulk material loading and unloading. Parameter configuration is directly related to actual working conditions. Lifting capacity, span, lifting height, speed, and grab bucket volume are selected based on material type, bulk density, and on-site operation method. Different application scenarios use different configurations.

Parâmetro	Value
Rated Capacity	3–30 t (typical 5–20 t)
Span	7.5–40 m (typical 10.5–31.5 m)
Altura de elevação	6–40 m (typical 18–28 m)
Classe de Dever	A5–A8 (mainly A6–A7)
Hoisting Speed	39.2–48.6 m/min
Trolley Speed	43.2–45.9 m/min
Crane Travel Speed	86.5–113.6 m/min
Grab Volume	0.75–10 m³
Fonte de Alimentação	3-phase, 380V, 50Hz
Modo de Operação	Pendant / Cabin / Wireless Remote
Ambiente de Trabalho	Interior / Exterior
Temperature Range	-25°C to +45°C

The specifications of the QZ-type grab bridge crane are configured based on on-site conditions, including technical parameters such as lifting capacity, span, lifting height, duty cycle, travel speed, and grab volume. WEIHUA can provide customized solutions tailored to different material types and operating frequencies.

Grab Types

The type of grab bucket is selected based on the physical properties of the material being handled, such as particle size, density, and shape, which directly affect grabbing performance.

Double-jaw grab bucket

The most common type, used for general bulk materials such as coal, sand, and grain.

Multi-jaw grab bucket

More cutting edges and better penetration into material piles. Suitable for irregular materials such as large ore, scrap steel, and iron chips, as well as sticky materials like sludge.

Toothed grab bucket

Equipped with teeth on the bucket edge for handling larger block materials (typically above 200 mm), such as large ore and limestone

Scissor grab bucket

Works on a scissor mechanism, with increasing closing force during operation and a wide opening range. Suitable for yard cleanup and ship hold cleaning, but less effective for initial grabbing of large lumps.

Different grab buckets are designed for different bulk materials and operating conditions. The table below compares their structure, suitable materials, working characteristics, and applications.

Item de comparação	Double Rope Grab	Multi-Tine Grab	Teeth Grab	Clamshell Grab
Estrutura	Two bucket shells connected by four wire ropes and a pulley system.	Multiple curved tines (typically 4–8) are mounted around a central hub.	Two bucket shells with reinforced cutting teeth on the bucket edge.	Two bucket shells with straight or curved edges, hinged at the top.
Opening / Closing Method	Opens when lowered and closes when lifted by the wire ropes.	Tines open when lowered and close toward the center when lifted.	Teeth penetrate the material during closing and grip the load.	Opens when lowered and closes when lifted to scoop material.
Typical Use	General bulk material handling.	Handling irregular, loose, or mixed bulk materials.	Digging and handling hard or compacted bulk materials.	High-capacity grabbing and dredging operations.
Suitable Materials	Coal, sand, gravel, grain, ore powder, and other loose bulk materials.	Scrap steel, municipal waste, sludge, clay, soft ore, and mixed materials.	Rock, limestone, cement clinker, hard ore, and oversized materials.	Large lump materials, dredged sediment, ore, and bulk cargo.
Recommended Material Size	Best for particle sizes below 100 mm.	Suitable for mixed particle sizes and irregular materials.	Best for particle sizes above 200 mm or compacted materials.	Suitable for medium to large lump materials and dredging work.
Principais características	Simple structure and stable operation.	Multiple tines provide a strong gripping force from different directions.	Reinforced teeth improve penetration into hard materials.	Large bucket capacity with efficient scooping performance.
Vantagens	Low maintenance, reliable operation, high efficiency for loose materials.	Excellent gripping performance for irregular materials.	Strong digging capability and high wear resistance.	Large payload per cycle with good sealing performance.
Limitations	Not suitable for large blocks or compacted materials.	Lower filling efficiency when handling fine powders.	Higher self-weight and increased tooth wear.	Requires a larger opening space and is less suitable for fine materials.
Typical Duty Class	A3–A6	A4–A6	A5–A8	A4–A8
Aplicações típicas	Power plants, cement plants, mines, warehouses, and material yards.	Steel plants, scrap yards, waste treatment plants, ports, and recycling facilities.	Mines, quarries, cement plants, and steel mills.	Dredging projects, ports, shipyards, and bulk cargo terminals.

The grab bucket directly affects material handling efficiency, filling rate, and service life. Different grab designs are suitable for different bulk materials, particle sizes, and working conditions.

For more information about grab bucket types, selection guidelines, and application differences, read our Caçamba para grua.

Princípio de funcionamento

A QZ Grab Overhead Crane handles bulk materials with a grab bucket suspended from the trolley. During operation, the crane travels along the runway while the trolley moves across the bridge to the loading position. The grab bucket descends into the material pile, closes to collect the material, and is lifted to the required height. The crane then carries the load to the unloading point, where the grab opens to discharge the material before returning for the next operation.

Position – Move the crane and trolley above the material pile.
Lower – Lower the grab bucket into the material.
Grab – Close the grab bucket and collect the material.
Lift – Raise the loaded grab to the travelling height.
Travel – Move the crane to the unloading location.
Unload – Open the grab bucket and release the material.
Return – Move the empty grab back to the loading area.

Vantagens

High handling efficiency — Grab cycle time is typically 30–60 seconds, suitable for continuous loading and unloading.

Strong load capacity — Rated capacity ranges from 3t to 30t, adaptable to different bulk material volumes.

Wide material application — Works with coal, ore, sand, grain, scrap steel, and similar loose materials.

Stable structure design — Double girder frame supports spans up to 40m with reduced deformation under load.

Flexible grab options — Mechanical, hydraulic, and multi-jaw grabs available for different material conditions.

Industrial duty performance — Duty class A5–A8 supports long-hour and high-frequency operation environments.

Aplicação

Ports and terminals

coal, iron ore, clinker, grain, bulk cargo

Steel industry

scrap steel, iron ore, coke, sinter

Power plants

coal, biomass fuel, and ash handling

Cement plants

limestone, clinker, gypsum, coal powder

Mining industry

ore, stone, tailings

Waste treatment plants

municipal waste, sludge, recyclable bulk materials

QZ Grab Overhead Cranes are built for handling bulk materials such as coal, ore, sand, limestone, clinker, grain, scrap, and industrial waste. They are widely used in steel plants, mines, power stations, cement plants, and material storage yards for continuous loading, unloading, and stacking operations.

Safety Systems

Overload protection device: Cuts power and stops operation when the load exceeds the safe limit after the alarm stage.
Limit switches (travel & lifting): Restrict end positions of crane travel, trolley movement, and hoisting to prevent overrun.
Emergency stop system: Immediately shuts down all movements in case of abnormal or dangerous operation.
Buffer and end stop blocks: Absorb impact energy at rail ends to reduce collision damage and derailment risk.
Voltage and overcurrent protection: Prevents operation under unstable power supply or electrical overload conditions.
Motor thermal protection: Stops motor operation when the temperature exceeds the safe operating range.
Conductor rail protection cover: Prevents accidental contact between wire rope or equipment and live power rails.
Anti-collision system (optional): Detects nearby cranes and reduces speed or stops when a safe distance is not maintained.
Sound and light alarm system: Provides visual and audible warnings during operation or fault conditions.
Operation monitoring system (optional): Records load, working status, and fault data for operational control and maintenance reference.

Custom QZ Grab Overhead Crane

QZ Grab Overhead Crane is configured based on site conditions, material type, and working requirements. Design and selection are adjusted according to actual operational needs.

Lifting capacity: 3t–30t or higher for special applications
Span: 7.5m–40m based on workshop or yard layout
Lifting height: 6m–40m depending on storage or pit depth
Grab type: rope grab, hydraulic grab, multi-jaw grab, scissor grab
Grab volume: matched to material density and handling capacity
Duty class: A5–A8 for different working frequency levels
Control mode: pendant control, cabin control, wireless remote control
Power supply: customized voltage and frequency for regional standards
Working environment: indoor, outdoor, high temperature or corrosive conditions (optional protection design)
Additional functions: anti-sway system, anti-collision system, real-time monitoring system

WEIHUA provides customized design and configuration according to project requirements and application conditions. We will configure a suitable double-hook overhead crane for your project.

QZ Grab Overhead Crane Manufacturer and Supplier

WEIHUA supplies QZ grab overhead cranes with full production capability, covering structural design, fabrication, assembly, testing, and delivery. Solutions are configured according to project requirements, including lifting capacity, span, grab type, and working duty class. Each unit is produced under industrial standards for long-term operation in demanding environments. For technical consultation, customization, or quotation, please contact us for detailed support. eeds. For technical support or project inquiries, Contate-nos for a tailored solution.

FAQ

What is a QZ Grab Overhead Crane used for?

It is used for loading, unloading, and transferring bulk materials such as coal, ore, sand, grain, and scrap steel.

What industries use grab overhead cranes?

Common applications include ports, steel mills, power plants, cement plants, mining sites, and waste handling facilities.

What grab types are available?

Options include rope grab, hydraulic grab, multi-jaw grab, and scissor grab, selected based on material type.

What is the typical lifting capacity?

Standard range is 3–30 tons, with customized models available for higher requirements.

Can the crane be customized?

Yes. Span, lifting height, grab volume, control mode, and duty class can all be designed according to site conditions.

What is the duty class of this crane?

It is typically designed for A5–A8 working duty, suitable for frequent and heavy operation.

What control methods are available?

Pendant control, cabin control, and wireless remote control are available depending on application needs.

Que sistemas de segurança estão incluídos?

Overload protection, limit switches, emergency stop, and optional anti-collision and monitoring systems are available.

Serviço Pós-Venda

Fundada em 1988, a Weihua evoluiu para uma líder global no campo da manufatura inteligente na China. Somos especializados em I&D e produção de gruas inteligentes, ao mesmo tempo que oferecemos soluções AGV. As nossas equipas profissionais de engenharia, entrega e pós-venda fornecem suporte técnico multifacetado, soluções personalizadas, orientação de instalação no local e serviços globais de resposta rápida para garantir que cada projeto opere de forma segura e eficiente.

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Manutenção de stocks de longa duração de componentes críticos para garantir entregas rápidas e manutenção sustentada.

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Serviço Pós-Venda Abrangente

Fornecendo suporte profissional de ponta a ponta, desde a instalação e comissionamento até atualizações e resolução de problemas.

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Por favor, especifique o seu requisito referindo-se aos seguintes aspetos:

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