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How to Choose a Grab Crane for Your Business

DATE: Jun 4th, 2023

1. Grab Crane General introduction

Grab crane (in other words: grabbing crane or bucket crane) is one of lifting equipment with grab spreader, widely used in port, yard, station freight, mines, power plant, refuse recycling, wood-fired co-generation power stations and steel production factory etc. Kingda grab crane mainly used for bulk material and recycling’s handling and shipment, for example:round log, mineral, coal, sand and gravel, clay, stone, grain, furnace slag, steel scrap, cement, renewable resource, gypsum, iron ore and so on.
Kingda grab crane is a automatic load handling device, its loading and unloading are controlled by driver or PLC intelligent system, no need personal assistance, avoiding heavy labor, handling efficiency is greatly improving finally. Grab crane generally is divided into overhead grab crane, gantry grab crane and folding-jib grab crane, in this article, we will talk about overhead grab crane and gantry grab crane only.

2. Grab Crane Characteristics

2.1 Improving production efficiency

For example: before the application of grab crane, loading and unloading mineral fines in yard, 12-16 worker will be needed in cabin, one worker-one spade, two workers as a team, one team fitted with a big net sling, one spade-one spade mineral fines is thrown into net sling, one net sling’s maximum capacity is 4t mineral. Under this condition, in one cabin, Maximum working capacity is 200t mineral fines in 8 hours. Now, under the assistance of big grab ship unloader, working capacity can up to more than 2000t, working efficiency is boosted greatly.

 2.2 Improving production safety

For example: before the application of grab crane, loading and unloading round log in yard, 4-6 worker in cabin. First, small wire rope cross in round log’s gap again and again, forming a wanted dimension, hanging wire rope’s two ends on the hook, lifting 1m-2m, let one ends of round log up; then, the worker need to take a φ16-28mm wire rope, there is a hook tied in the end of this rope, the rope and hook will be throw out from log’s up end and log’s gap;
Third, on the other end, one worker should catch the rope and hook, otherwise, it will drop in the log hill, the same work need to repeat again. In the process, ground log will roll maybe, crushing worker’s foot and hands, or wore rope cut off in the air because of over loading log, dozen or many dozen logs drop from the air, worked will be died or hurt. While, after the ground log grab crane’s invention, personal injury accident is reduced greatly.

3. Grab Crane Classification

Grab crane can be divided by crane type, crab type and driving type.

3.1 By crane type

Kingda grab crane can be divided into overhead grab crane and gantry grab crane. It also can be divided into single girder grab crane and double girders crane.
This kind of grab crane transport for bulk materials such as coal minerals, grain, clay, iron ore, sand or gypsum to pointed position.

3.1.1 Overhead grab crane

Kingda overhead grab crane mainly dedicated on bulk material, graininess material, steel scrap and waste.
Overhead crab crane is equipped with cabin room to control the crane, and there are open and closed two types control room; while, for some special working environment, cabin room will be not suitable, replaced by remote operation station room or wireless radio controller, for example: refuse recycling and blast furnaces granulating pit. All traveling mechanism employ wound-rotor crane motor or inverter motor (will follow end user’s requirements), speed controlled by resistor or frequency inverter. Grab crane’s working class can be: A6, A7, A8, working ambient temperature 20℃~+40℃,this grab crane canot be used in explosion proof condition and insulation requirement workshop.

1. grab’s open-close direction: paralleled to main girder or vertical to main girder;
2. crane’s rated lifting capacity includes grab’s weight;
3. when there is rain cover, crane’s top extreme dimension should be H+h;
4. when crane be used in outdoor, crane total weight and max. Wheel pressure should increase 5%;
5. crane’s power supply type;JGHX, DMHX and cable festoon;
6. for trolley, there standard trolley and weighting device trolley;
7. depending on material’s nature, grab be customized for sugarcane, garbage, log, steel scrap.

* Double girder overhead grab crane technical data sheet

                 Technical Parameter                  
                 Lifting capacity                                 t                               5                               10                               16                               20               
                 span                                 m                               31.5                               31.5                               31.5                               31.5               
                 working class                                 A6               
                  Lifting height                                 m                               20                               18                               22                               26               
                 speed                                   lifting                                      m/min     40.1     40.7     41.8     48.6  
    Cross travel        44.6 45.6 43.2 43.2
  long travel    86.4 89 87.3 87.3
  weight     trolley   Kg 5200 8200 14800 19300
  total weight   indoor 41300 50400 67900 75600
out door 42100 51200 69000 76800
  Max wheel pressure   indoor kn 144 196 263 312
out door 148 201 268 316
  Grab     Model   113 110 106 102 130 148 144
  Type   light medium heavy super heavy super heavy  heavy super heavy
  Volume(M3)   2.5 1.5 1 0.75 2.5 4 3
  Density t/m3   1-1.7 1.7-2.5 2.5-3.3 2.5-3.3
  Dead weight(kg)   2632 2615 2568 2546 8305 10123 9927
  Recommended rail      43kg/m QU70
Power source 380-600V 50HZ 3 Phase


3.1.2 Gantry grab crane

Kingda gantry grab crane mainly used in outdoor yard, to transport iron ore, coal and wood etc.
Material  specific gravityt/m³ Material  specific gravityt/m³
anthracite 0.7~1.0 pyriteblock 2~2.6
bituminous coal 0.8 manganese ore 1.7~1.9
lignite 0.6~0.8 magnesiablock 2.2~2.5
peat 0.29~0.5 powery magnesia 2.1~2.2
peat(wet) 0.55~0.65 copper mine 1.7~2.1
coke 0.36~0.63 copper concentrate 1.3~1.8
charcial 0.2~0.4 lead concentrate 1.9~2.4
anthracite dust 0.84~0.89 zinc concentrate 1.3~1.7
bituminous coal fines 0.4~0.7 lead-zinc  concentrate 1.3~2.4
plumbago 0.45 ore sintering caking 1.7~2.0
magnetite 2.5~3.5 bump sintering caking 1.4~1.6
hematite 2.0~2.8 lead singtering caking 1.8~2.2
limonite 1.2~2.1  lead-zinc sintering caking 1.6~2.0
zinc dust 0.7~1.5 big limestone block 1.6~2.0
pyrite cinder 1.7~1.8 mediu limestone block 1.2~1.5
lead-zinc briquette 1.3~1.8 small limestone block 1.2~1.5
pyrite pellet 1.2~1.4 quicklime  1.7~1.8
open-hearth slag(coarse) 1.6~1.85 rubble 1.32~2.0
blast furnace slag 0.6~1.0 dolomite(block) 1.2~2.0
lead-zinc liquid disintegrating slag 1.5~1.6 small piece dolomite 1.8~1.9
dry coal ash 0.64~0.72 gravel 1.5~1.9
coal ash 0.7 gravel(small block) 0.7~1.5
coarse sand(dry) 1.4~1.9 gravel(wet) 1.7
coarse sand(wet) 1.4~1.65 cement 0.9~1.7
fine sand(wet) 1.8~2.1 hydrated lime(power) 0.5
moulding sand 0.8~1.3 hydrated lime 2

3.1.3 single girder grab crane and double girder grab crane

Mainly for overhead crane, depending on the different main girder number. One main girder, we call single girder overhead grab crane; Two main girders, we call it double girder overhead grab crane.

3.2 By grab’s type

3.2.1 Clam-shell grab crane

Kingda crane clam-shell grab crane mainly used in port, yard, station goods yard, for kinds of bulk material: mineral ,sand, stone, clay, slag, cement...., also can be used for earth-rock excavation, railways construction, railway lay-down etc.

3.2.2 Multi-jaw grab or orange Peel grab  

Kingda multi-jaw grab or orange Peel grab suitable for steel scrap grab in steel plant and steel scrap sorting; refuse treatment; bulk wastes sorting, loading and unloading and transportation in construction site; automobiles disassembly, smelting and recycling. Grabs cutting teeth can be replaced in rated time, its material is high strength wear resistance steel, service life is extended. Petal shell can be changed by different working environment: all closed petal shell, semi-closed petal shell, broadside petal shell and short side petal shell. Wood fetch grab crane is mainly used for fetching different size of log, timber, piping, round barrel and so on, can fetch in single piece, or in many pieces, used under the assistance of gantry crane or tower crane. Straw bunch and transport needs a special customized material handling equipment in wood-fired co-generation power stations, for unloading, stacking, storing, feeding work. Straw handling grab crane features heavy working duty, suitable for humid working environment, heavy-dirty, continuous operation.

3.3 By grab’s driving mode

By grabs driving mode, there are hydraulic multi-jaw grab crane, mechanical grab crane and motor driven grab

3.3.1 hydraulic multi-jaw grab      

hydraulic multi-jaw grab itself has open-close mechanism, usually it use hydraulic ram to drive, organized by multiple jaws, mainly used in refuse recycling, wood-fired co-generation power stations and steel production factory etc., for waste handling, slag handling, steel scrap handling, straw handling....
No. Volume
Mode Material density t/m3 Pulley  wire rope Dia  φmm pulley Diam  φmm Dead weight  t crane lifting capacity t Close height A mm Open height B mm Close length C mm Open length D mm Witdth 
E mm
1 3 light ≤1 3 φ16 φ400 2.75 5 2922 3403 2200 3020 1820
2 2.5 light ≤1 3 φ16 φ400 2.73 5 2975 3514 2200 3120 1600
3 2 Mid 1~2 5 φ16 φ400 2.71 5 3084 3547 2150 2985 1520
4 2 Mid 1~2 5 φ16 φ400 2.73 5 3137 3658 2150 2985 1520
5 1.5 Mid 1~2 5 φ16 φ400 2.50  5 2984 3429 1950 2750 1360
6 1.5 Mid 1~2 5 φ16 φ400 2.57 5 3037 3540 1950 2860 1360
7 1 heavy 2~2.5 6 φ16 φ400 2.45 5 2855 3270 1850 2535 1150
8 1 heavy 2~2.5 6 φ16 φ400 2.5 5 2908 3381 1850 2635 1150
9 0.75 big heavy 2.5~3.3 6 φ16 φ400 2.3 5 2760 3144 1650 2340 1054
10 0.75 big heavy 2.5~3.3 6 φ16 φ400 2.32 5 2813 3255 1650 2460 1054
11 5 light ≤1 3 φ20 φ500 4.26 10 3795 4430 2820 3800 2050
12 4 light ≤1 3 φ20 φ500 4.24 10 3595 4153 2445 3431 2210
13 3 Mid 1~2 5 φ20 φ500 4.38 10 3595 4153 2445 3431 1810
14 3 Mid 1~2 5 φ20 φ500 4.42 10 3695 4332 2445 3431 1810
15 2 Mid 1~2 5 φ20 φ500 4.25 10 3640 4127 2200 3251 1550
16 2 Mid 1~2 5 φ20 φ500 4.29 10 3694 4268 2200 3251 1550
17 2 heavy 2~2.5 6 φ20 φ500 3.95 10 3640 4127 2200 3251 1550
18 2 heavy 2~2.5 6 φ20 φ500 4 10 3694 4268 2200 3251 1550
19 1.5 big heavy 2.5~3.3 6 φ20 φ500 3.78 10 3357 3814 2020 2969 1470
20 1.5 big heavy 2.5~3.3 6 φ20 φ500 3.82 10 3409 3955 2020 2969 1470
21 1 big heavy 2.5~3.3 6 φ20 φ500 3.46 10 3052 3445 1676 2280 1464
22 1 big heavy 2.5~3.3 6 φ20 φ500 3.5 10 3141 3578 1676 2280 1464
23 8 light ≤1 3 φ24 φ600 7.96 16 4545 5292 3205 4387 2370

3.3.2 Mechanical grab crane

Kingda mechanical grab itself has no open-close mechanism, usually driven by external force rope or interconnecting linkage, following operation features, grab can be divided into single rope grab and double rope grab, and double rope grab is the most popular mode in industrial application.

For double rope grab, there are supporting rope and open-close rope, they are wound on supporting drum and open-close drum separately. Double rope grab is a reliable, easy operation , high-efficiency and wide application lifting attachment. If the grab uses twice double ropes, it will be four ropes grab, with the same operation process as double rope.

Kingda single rope grab will use one rope for supporting and open-close together. Through a special lock catch, wire rope can carry out its supporting and open-close work in order. Single rope grab’s winding mechanism is simple one, but with low-productivity and seldom used in big hand heavy loading and unloading work.

3.3.3 Motor driven grab crane

Kingda motor driven grab mostly used for single rope and single girder grab crane, grab’s supporting rope is one piece wire rope, open-close mechanism is fulfilled by a motor. This structure is a simple mechanism, only can be used in small work amount, equipped with a electric hoist.

3.4 By control mode 

  • 1. cable pendant
  • 2.  radio remote control grab crane
  • 3.  semi-automated control grab crane
  • 4.  Fully automated control grab crane
  • 5.  cabin control grab crane
  • 6.  remote operation station (ROS) grab crane

3.4  By grabs manufacturing material

There are stainless grab crane, alloy steel grab crane.
Stainless grab crane specially use in food industries, for example: wine factory.


4. Grab Crane Operation Instructions

4.1 Driver Responsibilities 

  •   1.The basic requirements for operation: stability, accuracy, speed, safety, and rationality.
  •    2. Familiar with crane’s main parameters, purpose, components, operating methods, and maintenance requirements.
  •    3. Strictly comply with the basic operation, safety technology, and maintenance requirements of the "Crane Driver's Manual"                       
  •    4. The crane must issue a driving warning signal before start.
  •    5. The driver must closely cooperate with the hooker and keep pace. Moving and lifting heavy objects should only follow the signal sent by the hook operator, but whoever sends the "stop" signal, crane should stop immediately.
  •    6. The controller should be started step by step. Before the mechanism completely stops running, it is prohibited to directly turn the controller from forward to reverse for reverse braking. In case of emergency, the controller can be set to the reverse gear for braking.
  •   7. Proficient in using fire extinguishers.

4.2 Crane operation instructions

  •      1. Crane operators should operate the crane;
  •      2. When the crane is working, no one is allowed to stay on the crane;
  •      3. When the crane is running with a heavy object, it should be at least 0.5 meters above the highest obstacle on the heavy object running line;
  •      4. It is prohibited to throw objects directly from the crane;
  •      5. It is strictly prohibited to place flammable items on the crane. Tools and spare parts must be placed in specialized boxes, and it is prohibited to casually place them on large or small vehicles, to prevent them from falling off;
  •      6. It is strictly prohibited to lift heavy objects over people's heads;
  •      7. During operation, if any abnormalities are found in the crane, it must be immediately stopped for inspection, and the fault must be eliminated before operation;
  •      8. When the lifting brake of the crane suddenly fails, the driver should remain calm and take appropriate measures based on the specific situation. If the surrounding environment does not allow the lifted object to be directly dropped, it can be lifted repeatedly and the crane or trolley can be started to select a suitable location to drop the lifted object, without allowing it to fall freely;
  •      9. When lifting the grab, the speed of the lifting rope and the open-close rope should be equal, to ensure that the force on the steel wire rope is uniform;
  •     10. It is not allowed to use a grab to grab a whole piece of object;
  •     11. Before each shift, check the fastening of the rope at the suspension of the grab and the condition of the guide wheel of the grab opening and closing rope.

4.3 End of driver's job responsibilities

   ► 1. After the grab crane’s work is completed, place the grab on the ground and do not hang it in the air;
   ►  2. Cut off the main power switch in the protection box;
   ►  3. Inspect each mechanism and lubrication according to regulations;
   ►  4. All problems and solutions found during the operation and inspection, should be recorded in the handover manual. Only after handing over all the question to next driver, can the crane be left;

4.4 Operation notes

  1. ► 1)  Before power transmission, check that all controllers are stopped at zero and that the switch positions are correct. The circuit breakers of each mechanism on the control cabinet are closed, and the railing door is closed;
  2. ► 2)  Press the power button to power on, observe if there are any abnormalities in the electrical components, and confirm that there are no errors before operating each mechanism;
  3. ► 3)  The lifting and long travel-cross travel mechanism use controller to control the motion, same as general crane;
  4. ► 4)  The brakes of the lifting mechanism should be inspected every shift, and the brakes of the operating mechanism should be inspected every 2-3 days. If problems are found, they should be adjusted and repaired in a timely manner;

4.5 Grab operation

  1. ► 1)  Grab opening operation: Lower the lifting and open-close mechanism simultaneously to the appropriate position, stop lifting mechanism to lower, open-close lower continuously, the grab open gradually. Finish grab operation;
  2. ► 2)  Grab closing operation: open-close drum starts to lifting motion, grab’s top pulley with no move, the bottom pulley start moving up, the open-close motion been finished when grab tooth cross together. During open-close process, lifting drum make some lifting motion, ensure that the lifting steel wire rope does not sag;
  3. ► 3)  Grab’s up and down operation: no matter the grab under open or close, the lifting movement can be operated at any time. The lifting drum and open-close drum should operate at the same time.
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