In order to ensure safe and efficient operation during the use of lever chain cranes, the following protection and inspection methods need to be adopted:

1、 Security protection measures

Overload protection device

Function: To prevent overloading operations of cranes, avoid major accidents such as main beam breakage, arm folding, or complete machine overturning.

Type: Electrical overload limiter (composed of load sensor and secondary instrument panel), which automatically cuts off the lifting force and stops operation when the lifting weight exceeds the rated value.

Maintenance: Regularly check sensor sensitivity to ensure accurate secondary dashboard display and avoid misoperation or failure.

Hook lifting height limit device

Function: When the hook rises to the design limit position, it automatically cuts off the power supply to prevent the hook from lifting or falling to the ground.

Requirement: Adequate safety clearance height should be reserved above the limiter (such as exceeding the obstacle by more than half a meter) to ensure safe braking travel.

Maintenance: Test the flexibility of the limiter action, check whether the contacts are worn, and ensure that there is no jamming phenomenon.

braking device

Function: During the lifting or lowering process, ensure that the heavy object stays stable and prevents slipping.

Type: Mechanical brake (such as pawl ratchet), hydraulic brake, etc.

maintain:

Check if the brake oil level is appropriate and if there is any oil leakage.

Test the fit between the brake pads and brake wheels to ensure even wear and no cracks.

Adjust the brake clearance to avoid excessive braking failure caused by excessive clearance or excessive wear caused by insufficient clearance.

Travel limit device

Function: To prevent collisions between large vehicles, small vehicles, or lifting mechanisms when they reach the end of the track.

Type: Combination of travel switch and safety ruler impact block.

Maintenance: Check whether the travel switch contacts are sensitive, whether the safety ruler is firm, and ensure that the power can be cut off in a timely manner in case of misoperation.

Anti stripping device

Function: To prevent the steel wire rope from falling off the pulley or drum, and to avoid equipment damage or personal injury.

Maintenance: Check if the anti groove device of the pulley is intact, if the wire rope is wound neatly, and if there are no grooves, knots, or twists.

Electrical protection device

Function: To prevent electrical faults from causing safety accidents.

Types: Short circuit protection, voltage loss protection, zero position protection, overcurrent protection, etc.

Maintenance: Regularly check the insulation performance of cables, clean dust from electrical equipment, and ensure reliable operation of all protective devices.

2、 Testing method

routine inspection

content

Check if key components such as hooks, wire ropes, brakes, controllers, and limiters are intact.

Test whether safety devices (such as overload limiters and limit switches) are sensitive and reliable.

Observe whether the crane runs smoothly and whether there are any abnormal sounds or vibrations.

Frequency: Conducted before each shift, jointly completed by operators and handover personnel.

weekly inspection

content

Check the contact and corrosion of the contactor and controller contacts.

Test the wear level of the brake friction pads.

Check whether the connecting bolts are tightened, whether they are loose or missing.

Frequency: once a week, jointly completed by operators and maintenance personnel.

monthly inspection

content

Check the lubrication condition of each part and add or replace lubricating oil in a timely manner.

Test the performance of electrical control components to ensure no aging or damage.

Check if the protective devices (such as buffers and windproof devices) are intact.

Frequency: Once a month, completed by professional maintenance personnel.

annual inspection

content

Comprehensively inspect the performance of the crane, including metal structure, transmission mechanism, electrical system, etc.

Check the aging condition of electrical components and cables, and replace vulnerable parts.

Conduct stability tests to verify the crane's ability to resist overturning moments.

Frequency: Conducted once a year by a professional inspection agency.

Special inspection

No load test: Run each mechanism under no-load conditions to check if the performance is normal.

Rated load test: Verify the load-bearing capacity of the crane through a rated load test.

Dynamic load test: Conduct a dynamic load test at 1.1 times the rated load to verify the performance of each mechanism and brake.

Stability test: conducted in the most unfavorable position or state within the specified working area to test the ability of the crane to resist overturning moment.

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