For the newly designed and manufactured grab device, its external dimensions and parts must be checked against the design drawings, and check whether the lubrication holes are unblocked, whether the grease is filled as required, and for the rotating parts (such as pulleys, guide rollers, etc.) , manpower should be applied to observe whether it is flexible to rotate, whether the metal spatter on the surface of the weld of metal structural parts (usually using gas shielded welding), the weld bead, oxide scale, and welding slag are removed, whether there are cracks or pores, and whether the quality of the cut surface of the plate is excellent.

When the grab is closed, the edge of the adjacent jaw should be tightly fitted, observe and check whether it is misaligned, whether the various surfaces that are not lubricated are sandblasted, surface is cleaned to Sa2.5 level, and the paint is up to standard (the primer is thick abt 40 microns, the topcoat is 70 microns thick, 120 microns). The weight of the grab is marked by weighing.

Then, the grab device is tested for no-load operation, that is, the lifting rope is suspended by the lifting support rope to raise and lower the closing rope, and it is observed whether the opening and closing action of the grab is normal, and whether there is noise at the hinge shaft. Check if there’s difference between the maximum opening value and the design value, and check whether the driving, transmission and braking devices in the self-powered grab are reliable. Then, the grab device is subjected to a grab material test. The pile of the scheduled loading and unloading material can be set, so that the grab bucket is lowered to the pile at a height of 1 m above the material, the lifting support rope is relaxed, the material is lifted and closed, and the material is lifted or lowered to open and discharge. Usually more than 3 times of pick and place, weighing each time the material is handled, the average is calculated to check the error with the design requirements.