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Excavator’s Grab

2015-03-05 18:13
1. Summarize
5T hydraulic grab is designed with rotation function to be used in excavator for grabbing steel scrap, ore and etc, at working site such as port, stock yard, building site and so on.
1.1 Performance index
1.2 Operation rules
① Grab used for steel scrap.
② Check SWL and actual loading of rotator, notice the overload is prohibited.
③ Check the speed and direction of grab, as well as the operation of control handle.
④ The loading shall be lifted up from ground or materials before rotator starts work, that’s to say, rotator can’t be used while grab touching ground or materials.
⑤ Operator shall watch the load while lifting, to prevent grab from freely rotating because of wind or own instability due to no braking torque on rotator while without pressure, so Inverse operation on rotator is necessary on occasion.
⑥ To prevent hose touching from any barrier.  Damaged hose or hose coupler might cause dropping and continues rotating of the load.
⑦ For better closing, moderate up lifting is required while grab closing.
⑧ Excavator can not lie on rotator with self weight during working or pausing.
1.3 Operation condition
The grab is used in excavator outdoors. The working temperature of hydraulic system shall be::-25℃~+50℃。
The grab can not be used under water.
2.Operation Instruction
2.1 Operation
① Please in strict accordance with control standards after installed excavator on operation of opening and rotating of grab.
② Please cautiously comply with the Safety Criterion during grab’s operation.
2.2 Use
2.2.1 Initial Use
——Fasten lifting frame to excavator by pin roll, make sure joints of bolts and pin rolls safety.
——Check the safety of installation parts on rotator and lifting frame and beam.
——Prevent rotator from transverse load.
——Check any breakage or loosen on pipe fitting and hose of hydraulic cylinder and rotator.
——The grab’s SWL can not exceed the rotator’s SWL rang, while the axial working load shall be no more than7500kg.
——Hydraulic oil temperature range: -25℃~+50℃. To ensure the normal viscosity number.
——Working pressure of rotator is suggested to adjust to 200bar, while of  hydraulic cylinder is suggested to adjust to 250bar.
——There are four oil ports, by jointing with four reserved oil ports on excavator through four hoses, two of them are used to control horizontal rotating, the other twos are used to control the opening and closing of hydraulic cylinder. Check the safety of pipe fittings of each joint.
——Hydraulic oil shall be drove cycling in pipe for a while before the grab starts to work,  letting impurities be recycled by filter and make sure the cleanness of hydraulic oil.
2.2.2 Daily use
——Check the installation safety of lifting frame and pin roll of excavator.
——Check if any looseness of bolts on rotator.
——Check if any breakage or looseness on connect fitting and hoses of hydraulic cylinder and rotator.
——Before starts rotator run, grab shall be lifted away from ground or materials.
——Under water using of grab is prohibited.
——Operator shall watch the load while lifting, to prevent grab  from freely rotating because of wind or own instability. Inverse operation on rotator is necessary on occasion.
——Excavator can not lie on rotator with self weight during working or pausing.
2.3 Storage
① When grab is not used, the scoops shall be open while piston rod contracted to cylinder.
② Separate lifting frame from excavator, disassemble pipe fittings and hoses jointed to excavator, seal the oil port with plug screws.
③ Prevent rotator from press.
④ Grab shall be lie up vertically on flat ground, to avoid the environment of humidity and wide temperature range.
2.4 Transportation
When transportation, scoops shall be open while piston rod shall be contracted to cylinder. Grab shall be lie up virtually on flat foundation, fixed tightly by rope on four ends, to avoid break or topple.
3. Maintenance
3.1 Maintenance
① Regular lubrication to fixed pin roll of end cover on rotator is required.
② Regular Albany grease or similar grease to lubrication points on grab is required.
3.2 Daily inspection
① Check the safety and if any wear of deformation on end cover, pin rolls, cylinders and each jointed pin rod of scoops per week.
② Check the safety of each fastener on grab.
③ Regularly check if any breakage or oil leak on hoses and couplings of hydraulic cylinder or rotator.
④ Regularly check the two way oil pressure of hydraulic system on excavator.
3.3 Repair
3.3.1 Summarize
The following points shall be paid attention,
While the grab is opening, separates grab from hoses connected to excavator, and then disassemble the pin rolls on lifting frame, after that take down grab from excavator.
3.3.2 Disassemble
a) Scoops
Lay down the grab in open mode, support the down frame on foundation to keep pin rolls without press, and disassemble as following steps,
——Remove pin rolls of hydraulic cylinder on scoops.
——Remove central pin rolls on scoops.
b)  Hydraulic cylinder
Lay down the grab in open mode, vertically fasten lifting hydraulic cylinder, and loosen clamp nuts on piston rod fixed block(on scoops) and hinges ear of hydraulic cylinder(on beam), remove hoses, and then take down hydraulic cylinder.
c) Rotator
Firstly, remove the pin rolls and fastening bolts from jointed top part of rotator and lifting frame, ant then loosen bolts and nuts from jointed bottom part of rotator and beam, and the rotator could be taken down.
3.3.3 Repair
① Replacement of pin rolls and bearing bush
Disassemble scoops according to 4.3.1, replace the wear bearing bush from scoops with new one.
①  Replacement of pin rolls of scoops
The connecting surface shall be check while replacing the bearing bush, if heavy wear, pin rolls shall be replaced, too.
②  Replacement of hydraulic sealing
Screw out spigot nut of cylinder, and drew out piston rod, and then screw out spigot nut from piston rod, replace the sealing.
③  Rotator
If any instability or occasionally pause on rotator, please contact SHYP instead of disassembling it by yourself.
3.3.4 Assembling
Assemble the grab in reserve order that it was disassembled, pay attention to avoid breakage on wrapped components during assembling.
The working status shall be in accordance with the designed technical parameters after assembled.
The repair of important parts, please contact with after-sales of SHYP.