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Maintenance and Repair of Remote Control Clamshell Grab

2015-05-11 16:31
1.1 Maintenance
1.1.1 Lubricate every twist joints, every 8 working hours. The lubrication oil is Great 0# or other similar oil.
1.1.2 Lubrication (see drawing VII) 
Lubricating A: add oil every 8 working hours
When grab stop working, add oil to the part A and steel rope one time every one month.
When grab stop working, add oil to the piston rod which exposed in the air one time every one week.
Clear out dust and rubbish while lubricating.
1.1.3 When finding any part of the grab getting rusty, please paint them after removing the rusty.
 Paints:  (1st coat) high-build epoxy Zinc primer
         (2nd coat) intermediate alloprene
  (3rd coat) top coat-modified acroleic acid alloprene.
1.1.4 Change hydraulic-oil
It is advisable to change hydraulic-oil after first 500 working hours; then change the oil every 1000 working hours. Keep closing the oil box when change the hydraulic-oil. First, put container on the middle of under roof beam, open the cover on the bottom and bolt of oil trunk, then get the hydraulic oil inside the oil trunk out. Add oil into oil trunk through the top mouth of Breather filter. The hydraulic-oil is transfused by oil pumps and small impurities should be filtrated through an oil filter with a precision of 5~10μm for fear that those impurities lock the valve core of single directional valve, which will make the grab can not work. After adding oil, open the un-loading grab, loose the dipstick, move the moving board at least 10 cycles, in order to draw out the air inside hydraulic cylinder and pipes. After drawing the air out, check the oil level, the oil height should approach the first gap. If the oil is lower than this level, please add oil. At this time, the piston rod should retract into hydraulic cylinder completely. The following photo shows the dipstick:
 1.1.5 Check the installation of hydraulic system bolt on parts
After using grab each time, users should clean-up materials and dust on the grab in time. Check the installation of hydraulic system bolt on parts. If finding blots loose, to fasten them, so to avoid oil spills and other failures.
1.2 Daily examine and repair
1.2.1 Rope Guide Rollers
—   Every guide rod should turn easily, repair them if jammed. If the guide rod is over-abrasion, change it.
1.2.2 Hydraulic cylinder
—   Check 6×2 bolts and nuts for fixing the hydraulic cylinder which must be firm. Check the big nuts of piston rod which must be firm. Check the airproof of hydraulic cylinders which are not leak seriously.
1.2.3 Hinge
—   Every hinges’ oil-orbit must be opened up. If the oil passages are impeded, clean and oil them. If the dimension of internal wear is more than 20% of the original or the bearing, the bush are broken, it must be changed.  
1.2.4 Bush
—   It must be changed if the diameter is big than 20% of the original after wearing. 
7.2.5 Steel rope
—   It must be checked, oiled in time, and replace it over the condemning limit.
1.2.6 Hydraulic-oil
—   The hydraulic-oil used in the hydraulic system should be the anti-friction type. And now the grab adopts the No.46 anti-friction hydraulic-oil made in China, it is similar with the ISO HM-N46.
—   During transfusing oil into oil trunk in hydraulic system, the hydraulic-oil is transfused by oil pumps and small impurities should be filtrated through an oil filter with a precision of 5~10μm for fear that those impurities lock the valve core of single directional valve, which will make the grab can not work. In oil transfusing, the moving board should be set in the lowest place, that is to say, the piston-rod fully retracts in cylinder.
1.3 Shackle
—   When finding any conditions below, scrap the shackle.
a. Cracks in any part of the shackle;
b. Deformation is beyond 5%;
c. Pin of shackle being unable to turn around;
d. The abrasion in any section of the main parts of the shackle and its pin is beyond 5%.
—   The shackle can't be engaged in re-heating or welding,and can't be reused after repairing.
1.4 Hydraulic valve block
— Grab hydraulic block is installed in the middle of the under roof-beam. The main control valve of hydraulic system parts are installed in the valve, the normal work of the various control valves to ensure that the grab can be opened or closed and normally work.
—   When opening grab has made a great impact, through adjusting the throttle valve(1801009), in clockwise direction, reducing the throttle path and slow down the speed of grab opening; the degree of throttle valve opening can not be too small, generally 50% opening degree. In addition, checks whether the electromagnetic valve B plug a power, under normal circumstances the valve should be in a power state.
—   When connecting the power, can not open the grab. The first check the two sets of electromagnetic valve A / B should be installed on block is power; Second, check the handle location of valve, whether the location of valve is the greatest. The others, using the emergency hand-pull mechanism to open the grab, such as the foregoing method of operation 5.6.
—   When the grab can not be closed, the first, check whether the electromagnetic valve A is in non-power state; Secondly, check the oil level, whether it meets the requirements, by observing the level of oil, usually requiring hydraulic oil surface should be above the medium of the oil level gauge. In addition, check whether one-way valve within the hydraulic cylinder is working properly. Method I: removing one of the high-pressure hoses, the hose is connected between the valve block and the oil trunk upper part, and stop leak of hose, then pulling slip board, then press remote “open” button on the remote controller, if the grab open slowly, that means hydraulic cylinder has problem. If not, that means this hydraulic cylinder has no problem, and reset the hose to its former place. Use the same method to deal with the other hydraulic cylinder by removing the other high pressure hose. If both of the hydraulic cylinders have no problem, that means the hydraulic valve blocks have problems, please check them. Method II: Lifting the slip board, make ears close to cylinder out walls, if the noise like: sisi can be heard, that means the inside of one-way valve has problem. If not, that means the cylinders have no problem.
--- To see Hydraulic System Part List of 28T Remote Control Grab.
--- The drawing of Hydraulic valve block sees drawing IX.
2. Other Notices
2.1 The hanger on the board of the top roof beam can be lifted up perpendicularly only when the grab repairing, and can't be used for lifting up the grab.
2.2 When operation or shutdown, the balance frame shouldn't hit hydraulic cylinder of grab, especially, can’t hit piston rod of hydraulic cylinder.
2.3 When disassembling the hydraulic cylinder, please protect the electromagnetism valve and the piston rod.
2.4 When shutdown, overspread the water-proof cover and tighten it.
2.5 The lifting capacity of the big shackle on balance frame is 32t, and the shackle can't be used in other ways.
2.6 When grab is closing, if the grab can’t open after pressing the remote emitter, it is maybe something wrong with the electric-control system in moving board. At this time, it is advisable to open the hydraulic system cover and switch on the electromagnetism valve by hand. And when the grab is pulled up, the grab will be open. Please repair the remote system and the electric system before reusing the grab.
2.7 Grab oil cylinder piston rod by bearing force damage does not belong to product quality guarantee freely range.
2.8 Connectors, plug, cable, hull, from external damage does not belong to product quality guarantee freely range.