Construction crane, hook is a very important part, cranes work rely on the hook for lifting weights, then lift to remove. So when crane maintenance and crane maintenance is essential, maintenance hook hook do first check, the following detailed hook method.
Crane hook mainly consists of pulleys, pulley wheel, anti-decoupling device, Leptospira, beams and bearings, bolt, nut, waveguide components, such as rope and plywood. In order to ensure the crane hook normally used, crane operators, maintenance staff as appropriate security checks on these parts, includes 3 items: first, check the technical documentation, the second is to check the appearance and surface cracks, three is to measure the amount of wear, opening, torsion, etc.
1, check the technical documentation
Before entry into service of new cranes, the operator should check the hook Assembly-related technical documents. Signs mark the rated load of the hook Assembly should be consistent with the actual lifting load, technical documentation and factory certificate should be complete.
2, Visual inspection
Crane operation personnel daily should hook Assembly of appearance for check, the parts of requirements following: pulley in pulley axis Shang turned should flexible, no obviously pine open; pulley of round margin should no damaged or crack, or should replaced; anti-decoupling device should opening and closing freely, its spring should intact, to prevent wire rope from hook body Shang sliding off; hook body in beam at of bearing Shang should turned flexible; round nut and the combination bolt cannot has loose.
3, check the hook surface crack
First clean the hook body with kerosene, and then check that the hook is used 20 times a magnifying glass crack, flaw free coloring if necessary. For very large-tonnage crane hook, should also use non destructive testing (magnetic flaw detector, ultrasonic) check hook inside and outside for crack. Such as leptospirosis and internal cracks on the surface should be replaced immediately.
4, measuring hook body geometry
At the time of periodic inspection of crane, hook should use a caliper or caliper measurement wear of surface wear. When wear reaches the size of the larger force section 10% should be replaced. Overhaul of crane, hook assemblies should be dismantling and measured the pulley shafts, beams, bearing wear and splint shaft hole. When wear reaches the size 5%, and should be replaced.
(2) the opening of the
Hook opening measurement method is as follows: as hook signs indicate the load on load test was carried out, progressively load incrementally increased to 1.25 times of the rated load, lifting time of not less than 10min. After uninstalling using calipers to measure the opening hook, the value is compared with the original opening, the opening of increase should not exceed 0.25%.
When you enable the new hook, available punches in Leptospira rush 1 on each side of the opening tag, measure the distance between the tag and record it as the original opening size. Hook opening distortion than the original opening of the 15%, should be replaced.
(3) the torsional deformation
Test hook torsion deformation measurement method are as follows: put a ruler on the side hooks of the side, observing ruler and hook-and-lateral clearance. If different hooks on either side of the gap, that hook of torsional deformation. If you want accurate measurement of torsional deformation of hook, you can remove it, on the platform with crossed feet detection. Leptospira torsional deformation exceeding 10 ° should be replaced.