Type: Four-Rope Double-Petal Grab
Applicable equipment: Crane
The four-rope double-jaw grab is a mechanical grabbing device controlled by wire ropes. It is mainly used for bulk cargo (such as coal, ore, grain, sand and gravel, etc.) loading and unloading operations in ports, docks, mines, power plants and other places.

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Description

Features

Applications

About Weihua

Description：

1. Product Overview
The four-rope double-jaw grab is a mechanical grabbing device controlled by wire ropes. It is mainly used for bulk cargo (such as coal, ore, grain, sand and gravel, etc.) loading and unloading operations in ports, docks, mines, power plants and other places. It is characterized by a sturdy structure, strong grabbing force and flexible operation. It is suitable for use with cranes or ship unloaders.
2. Structural features
Double-jaw design: It consists of two symmetrical jaws connected by hinges. When closed, it forms a closed space to effectively prevent material leakage.
Four-rope system: The opening and closing and lifting of the grab are coordinated by two support ropes (opening and closing ropes) and two closing ropes (lifting ropes). The power comes from a crane or winch.
High-strength material: The jaws are made of wear-resistant steel plates (such as Hardox or Q345B), and the cutting edge can be equipped with wear-resistant alloy blocks to extend the service life.
Balance beam structure: Optimizes force distribution, ensures smooth opening and closing of the grab, and reduces wire rope wear.
3. Working principle
Open state: the support rope is fixed, the closing rope is relaxed, and the jaws open by self-weight or external thrust.
Grabbing materials: the grab bucket falls to the material pile, the closing rope is tightened, driving the jaws to close and grab the materials.
Lifting and transportation: After the grab bucket is closed, it is lifted to the unloading point synchronously by the support rope and the closing rope.
Unloading: the closing rope is relaxed, the jaws open, and the materials are unloaded by gravity.

Features：

The four-rope double-jaw grab is an efficient and reliable bulk cargo loading and unloading tool, widely used in ports, mines, power plants and other places. Its core performance features are as follows:
1. Efficient grabbing capacity
Large capacity design: optimize jaw curve, improve filling rate, large single grab volume, and improve loading and unloading efficiency.
Quick opening and closing: four-rope coordinated control (two opening and closing ropes + two support ropes), sensitive movement, shortening the operation cycle.
Adapt to a variety of materials: can grab bulk cargoes of different densities such as coal, ore, sand and gravel, grain (by adjusting the shape and material of the jaws).
2. High strength and wear resistance
High-quality materials: The jaws are made of high-strength wear-resistant steel (such as Hardox, NM400), and the key parts (cutting edge, hinge shaft) can be welded with wear-resistant alloys or equipped with wear-resistant liners.
Impact-resistant structure: reinforced rib plate design, withstands high-load impact, suitable for hard materials such as ore.
Long life: key components such as pulleys and bearings are sealed and lubricated to reduce wear and long maintenance cycle.
3. Stable and reliable operating performance
Four-rope balance system: double support rope + double closed rope design, uniform force, avoid wire rope wear or structural deformation caused by eccentric load.
Anti-sway design: The center of gravity of the grab is optimized, reducing swing during lifting and improving positioning accuracy.
Sealed and leak-proof: The jaws are tightly closed to reduce material leakage (especially suitable for grain and powdery materials).
4. Safety and easy maintenance
Redundant protection: The double-rope system provides double insurance, and the grab can still be kept stable when a single rope breaks accidentally.
Modular design: The jaws, pulleys and other components can be quickly disassembled and replaced to reduce downtime.
Low failure rate: Simplified transmission structure, reduced hydraulic or electrical components (compared with hydraulic grabs), suitable for harsh environments.
5. Wide adaptability
A variety of capacities are available: ranging from 5m³ to 50m³ to meet the needs of different lifting equipment.
Customized options:
Dust-proof type (grain grab): Add sealing strips to reduce dust.
Anti-corrosion type (saline-alkali environment): galvanized or stainless steel.
Heavy duty (ore grab): reinforced hinges and cutting edges.
6. Energy saving and environmental protection
Pure mechanical drive: no hydraulic system required, no risk of oil leakage, lower maintenance cost.
Low noise: Compared with hydraulic grab, it has lower operating noise and is suitable for cities or areas with high environmental protection requirements.

Applications：

1. Port and wharf loading and unloading
Applicable materials
Coal: Loading and unloading of coal for power plants and steel mills.
Iron ore/bauxite: Ship loading and unloading or yard transfer of bulk ore.
Fertilizer/grain: Loading and unloading of bulk fertilizers, soybeans, corn and other agricultural products.
Sand/cement: Loading and unloading and transfer of building materials.
Application advantages
Efficient operation: Cooperate with portal cranes and bridge grab ship unloaders to achieve fast loading and unloading and increase port throughput.
Adaptable ship types: Can match bulk carriers of different tonnages, grab materials at the edge of the cabin, and reduce the workload of cabin cleaning.
Anti-leakage: Double flaps are tightly closed to reduce material spillage and reduce environmental pollution.
2. Raw material processing in power plants and steel mills
Applicable materials
Coal: Coal storage and transportation in thermal power plants.
Limestone/gypsum: Grabbing of raw materials for desulfurization and cement production.
Mineral powder/coke: Loading and unloading of raw materials for steel smelting.
Scrap steel/slag: waste recycling and transportation.
Application advantages
High temperature resistance: special material grab can withstand high temperature slag for a short time (customization required).
Impact resistance: high-strength structure is suitable for hard materials such as ore and scrap steel.
Continuous operation: with grab bridge crane, realize the automation of stacking and reclaiming.
3. Mines and gravel yards
Applicable materials
Ore/crushed stone: loading operation in open-pit mines or stone yards.
River sand/sea sand: excavation and transportation of construction sand.
Tailings/waste: cleaning and recycling of mine waste.
Application advantages
Strong wear resistance: thickened cutting edge and wear-resistant lining to extend service life.
Large capacity design: increase single grab amount and reduce energy consumption.
Adapt to harsh environment: dustproof and corrosion-resistant design, suitable for humid or dusty conditions.
4. Grain and agricultural product storage
Applicable materials
Wheat/corn/soybean: bulk grain loading and unloading in grain depots and grain and oil processing plants.
Feed/starch: transit and storage of agricultural and sideline products.
Application advantages
Dustproof seal: add rubber sealing strips to reduce grain crushing and dust.
Lightweight design: reduce deadweight and increase payload (suitable for low-density materials).
Sanitary and safety: stainless steel material is optional, meeting food-grade operation requirements.
5. Construction and infrastructure projects
Applicable scenarios
Sand/cement loading and unloading: raw material supply for concrete mixing stations.
Earthwork/slag transfer: foundation pit excavation, river dredging and other projects.
Garbage/waste disposal: construction waste sorting and loading.
Application advantages
Flexible adaptation: can match a variety of lifting equipment such as truck cranes and crawler cranes.
Quick changeover: modular design, easy to replace jaws to adapt to different materials.
6. Other special applications
Salt industry: Grabbing of sea salt and mineral salt (anti-corrosion treatment is required).
Chemical industry: Bulk chemical raw materials such as plastic particles and sulfur (anti-static design is optional).
Garbage power plant: Grabbing of domestic waste and biomass fuel (corrosion resistance enhancement).

Application of four-rope double-flap grab

About Weihua：

Weihua Heavy Machinery Co., Ltd. was founded in 1988. It is a large-scale equipment manufacturing enterprise mainly engaged in the development of bridge and gantry cranes, port machinery, electric hoists, reducers, bulk material conveying equipment, crane parts and other products.
Weihua has won more than 500 honorary titles such as "National Technology Innovation Demonstration Enterprise", "National Torch Program Key High-tech Enterprise", "National Certified Enterprise Technology Center", "National Quality Benchmark", "National Green Factory", and "National Industrial Design Center".
Weihua has 10 series and more than 200 categories of crane production and manufacturing qualifications. The leading products are widely used in machinery, metallurgy, mining, electricity, railways, ports, petroleum, chemical and other industries, serving national key projects such as West-East Gas Transmission, South-to-North Water Diversion, Olympic Projects, Hangzhou Bay Cross-sea Bridge, and thousands of large enterprises such as China Coal, China Shenhua, Sinopec, China Petroleum, Baowu Steel, etc., and are exported to more than 170 countries and regions such as Thailand, Malaysia, and Australia.

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