1. There shall be no deformation or weld seam de-welding. The rolling clearance between the inner and outer gantry shall be adjusted reasonably. It shall not be greater than 1.5mm. The rotation of the roller shall be flexible. The roller and shaft shall be free from cracks and defects. The amount of wheel groove wear must not exceed 10% of the original size.

2. Forklift two hoisting chains should be evenly tensioned, not to be distorted, and the ends are firmly connected. The pitch of the chain must not exceed 4% of the original length. Otherwise, the chain should be replaced. The sprocket rotation should be flexible.

3. The forks shall not be severely deformed and the welds shall be desoldered. There must be no cracks or welds on the surface of the fork. The root angle of the fork shall not be greater than 93° and the thickness shall not be less than 90% of the original size. The height difference between the left and right fork tips shall not exceed 3% of the length of the horizontal section of the fork. The positioning of the fork should be reliable. The bearing surface and the positioning surface of the fork should not have obvious defects. The clearance between the fork and the fork should not be too large and the movement should be smooth.

4. The connection between the lifting cylinder and the door frame should be firm. The hinge of the tilting cylinder and the door frame and the frame should be firm and flexible, and the matching clearance should not be too large. The cylinder should be well sealed, free of cracks and stable. Under the rated load, the self-sinking of the gantry is not more than 20mm and the inclination is not more than 0.5°. The lifting speed should not be less than half of the standard value at full load.

5. The overhead guard and the shelf must be complete and effective.