Before using a low clearance manual hoist for lifting operations, it is necessary to conduct a comprehensive inspection of the equipment status, environmental adaptability, and operating standards. The following are specific inspection points and analysis:

1、 Equipment appearance and structural integrity inspection

Core component damage detection

Hook and sprocket: It is necessary to confirm that the hook has no cracks, bending or twisting deformation, the sprocket tooth surface is intact and not worn, the hook body opening change rate is ≤ 15%, and the sprocket tooth thickness wear amount is ≤ 10% of the original tooth thickness.

Chain and wire rope: Focus on checking whether the chain has broken joints, corrosion, or deformation. If the diameter wear exceeds 7% or cracks appear, it should be scrapped immediately; The wire rope needs to be tested for wire breakage rate (single strand wire breakage ≥ 10% is considered scrap).

Shell and bracket: Check for dents and rust on the gourd shell, no cracks in the welding seams of the bracket crossbeam, and the strength of the support points must meet a safety factor of 3.

Mechanical structure stability verification

Gear and rack: Measure the meshing clearance of the gear (standard value ≤ 0.3mm), the straightness error of the rack is ≤ 0.5mm/m, and if the wear exceeds 20%, it needs to be replaced.

Tightness of transmission chain: Use a torque wrench to test the torque of the sprocket fastening bolts (such as M16 bolts, which need to reach 180N · m), and the tightness of the transmission chain should be able to slide up and down by 10mm.

Abnormal noise and looseness investigation: Run for 3 minutes without load, monitor the temperature of the bearing seat (≤ 70 ℃), and confirm that there are no metal friction sounds or component shaking.

2、 Functional component performance testing

Reliability verification of braking system

Static braking test: Under rated load, the brake should stop the load within 1 second, and the settling amount after 5 minutes of static placement should be ≤ 5mm.

Dynamic braking test: Simulate a 1.25 times overload condition, with a braking distance of ≤ 200mm. When the thickness of the brake pad wears down to one-third of its original thickness, it must be replaced.

Brake cleanliness: Check the friction surface for oil stains and dust, and adjust the brake clearance to 0.3-0.5mm.

Confirmation of lifting chain status

Knot and deformation correction: When the chain is twisted, it is necessary to use a chain wrench to adjust it section by section to ensure that the verticality error of the chain link is ≤ 2 °.

Lubrication and cleanliness: The chain needs to be coated with lithium based grease to remove surface sediment and iron filings. If the rust area exceeds 10%, it needs to be replaced as a whole.

Tightness of the pin shaft: Check the anti loosening mark on the end pin shaft of the chain to ensure that there is no displacement, and the wear of the pin shaft diameter is ≤ 5% of the original size.

3、 Assessment of compatibility between operating environment and load

Match the clearance height with the travel distance

Space scanning: Use a laser rangefinder to measure the minimum clearance of the lifting path, ensuring that the height of the hoist body+load height+safety margin (≥ 0.3m) is less than the available space.

Travel verification: Select the chain travel based on the lifting height, leaving a 10% margin to cope with operational errors.

Load stability control

Center of gravity calibration: Use a level to detect the deviation of the load center of gravity, which should be ≤ 5% of the load length. If it exceeds this limit, a balance beam should be installed.

Strength verification of lifting points: The lifting ears and straps must meet a safety factor of 4 times, and the welds must pass 100% magnetic particle inspection.

4、 Confirmation of the effectiveness of safety protection devices

Overload protection device verification

Mechanical clutch: Test the automatic disengagement function at 110% rated load, and recalibrate after resetting.

Electronic load limiter: Use a weight group to calibrate the load sensor, with an error of ≤± 2%.

Limit and anti detachment device

Travel limit switch: Simulate triggering test to ensure power-off when the chain has 2 remaining turns.

Anti detachment device: Check the gap between the chain plate and the chain (≤ 3mm), and ensure that there is no deformation or cracking.

5、 Operator qualifications and emergency preparedness

Qualification verification

Operators must hold a Rigger Level 2 or higher special equipment operation certificate, and the certificate must be valid.

At least 8 hours of practical training should be conducted annually, with a pass rate of 100% in the assessment.

Emergency plan preparation

Fault handling process: Develop a "On site Handling Plan for Gourd Faults", specifying measures to deal with working conditions such as chain jamming and overload.

Rescue equipment configuration: The site is equipped with hydraulic lifting devices, safety rope interception nets, and spare hoists (of the same specifications).

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment