Shanghai ENJUE Machinery Equipment Co., Ltd is one of the most experienced manufacturers and suppliers of single-rope grabs in China. If you're going to buy custom single-rope grabs made in China, welcome to get more information from our factory. For price consultation, contact us.
1. Clarify Your Working Profile - Four Core Questions to Ask Yourself
Before browsing any product specifications, please answer the following four questions. The answers will serve as the benchmark for all subsequent judgments.
What is the material to be handled?
For example: iron ore being unloaded at a port, scrap steel in a factory, rubble at a construction site, slag from an incineration plant, or grains in a granary?
What is the main task to be performed?
Loading: moving material from a stockpile to a conveyor belt or wagon → focuses on closing force and fill factor.
Sorting: picking out specific shapes/weights from mixed materials → requires a wide opening and precise control.
Dismantling/Grabbing: crushed concrete, scrap steel, etc. → requires jaws with strong impact and bending resistance.
Type of supporting equipment
The single rope grapple must seamlessly integrate with the crane body. Please confirm whether you are using:
Gantry crane (RMG)
Overhead crane
Portal crane
Or other specialized rail-mounted crane
Material Bulk Density & Grab Volume
Once the material density (t/m³) is known, the standard volume of the grab should meet the following:
Net weight per grab = Volume × Material Density × Grab Filling Factor (usually 0.8~0.95)
At the same time, this net weight must not exceed the crane's rated lifting capacity at that working radius.
Tip: If you already know how many cubic meters the grab requires, please provide that as well. The volume and density together determine the load per operation.
Crane Tonnage (Rated Lifting Capacity)
Please indicate the permissible load of the crane under grab operation conditions. Note: Grab self-weight + Net material weight ≤ Crane permissible load.
It is generally recommended that the single rope grabs self-weight accounts for 30%~50% of the rated load, with the remainder used for material.
2. Material Specific Gravity and Grab Strength Grades - Four-Stage Precise Division for reference
According to the bulk density and block characteristics of the materials being grabbed, industry standards divide grabs into four series: light, medium, heavy, and extra heavy. The table below provides the recommended grade and structural characteristics for typical materials:
| Intensity Level | Applicable Material Examples | Bulk density range (t/m³) (t/m³) | Structural Design Features |
|---|---|---|---|
| Light weight | Coke, furnace slag, grains, potatoes, lime, cement, clay, crushed stone, crushed bricks | 0.5 ~ 1.2 | The jaw plate is made of low-alloy steel, and the closing mechanism is lightweight, suitable for high-speed continuous loading and unloading. |
| Medium weight | Peat, large lump anthracite, compacted coal, clay, limestone, gravel, salt, wet sand bricks | 1.2 ~ 2.0 | The jaw plate and hinge point are reinforced, and the thickness of the wear plate is increased, making it suitable for medium wear. |
| Heavy weight | Limestone, heavy clay, medium-fine ore, hard rock, iron ore, lead concentrate powder | 2.0 ~ 2.6 | The key hinge points use cast steel components, and the jaw plate edges can be replaced with wear-resistant liners, significantly improving structural rigidity. |
| Super heavy weight | Large chunks of ore, manganese ore, sedimentary lump lead ore powder | 2.6 ~ 3.3 | Fully cast or high-strength welded box structure, with additional anti-collision ribs, suitable for extremely high impact and abrasion. |
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