The reasons for the inability to lift manually operated cranes (such as hand cranked hoists and chain hoists) involve multiple dimensions such as mechanical failures, operational errors, inadequate maintenance, and environmental factors, and need to be investigated one by one based on specific phenomena. The following is a systematic analysis and solution:

1、 Mechanical faults

Chain system issues

Chain jamming/breakage: The chain is stuck due to wear, corrosion, deformation, or overload; Forged defects in chain links and uneven wear of sprocket teeth may also cause chain jamming. For example, if the wear of the chain of a chain hoist exceeds 10% or if there are broken wires or knots, it needs to be replaced immediately.

Poor lubrication: The lack of lubrication in chains, gears, and bearings leads to increased friction and increased operational resistance. Special lubricating grease should be applied regularly to avoid the use of corrosive lubricants.

Brake and brake system malfunction

Brake failure: Insufficient braking force caused by excessive wear of brake pads, oil pollution, or spring fatigue; Damage to the pawl/ratchet may cause the brake to fail to release or lock. For example, if the brake pads of a hand-operated hoist do not separate, it will result in "only lifting without lowering".

Limit device malfunction: The pull rod of the flameout limit device is stuck, the contact is burned, or there is a circuit fault, which may cause the rising circuit to be unable to be powered on. It is necessary to check the activity and contact status of the limit device.

Damage to transmission components

Gear/bearing wear: Gear tooth breakage, tooth surface wear exceeding 30% of the original thickness, or bearing damage can lead to transmission failure; Bending of the shaft and damage to the keyway can also affect power transmission.

Hook/pulley issues: Cracks in the hook, excessive opening, or uneven wear of the pulley groove may cause heavy objects to detach or wire ropes to jump.

2、 Operation and usage issues

Overloading use: Exceeding the rated load of the equipment (such as lifting 11 tons of heavy objects with a 10 ton hoist) will exacerbate wear and tear, resulting in lifting difficulties or jamming. Strict adherence to load limits is required to avoid diagonal and impact loads.

Improper operation

Direction error: The direction of the handle of the hand-operated hoist does not match the lifting direction, or the operating force of the chain hoist is insufficient, which may result in the inability to lift.

Installation issues: Unstable device fixation, angular deviation, or adhesion of heavy objects to other objects can increase lifting resistance.

environmental factors

Temperature/humidity: Low temperatures cause lubricating oil to solidify, while humid environments lead to rusting; Dust and debris entering the interior of the equipment may block moving parts.

Corrosion and aging: Long term outdoor use leads to corrosion of metal components and aging and failure of rubber parts.

3、 Maintenance and troubleshooting suggestions

routine inspection

Pre operation inspection: Before each use, check the status of the chain, hook, brake, and limiter to confirm that there are no cracks, deformations, or abnormal wear.

Functional testing: Verify the lifting/lowering function during no-load operation, test the braking force and limit device sensitivity.

regular maintenance

Lubrication and maintenance: Regularly lubricate moving parts such as chains, gears, bearings, etc. according to the manufacturer's requirements, and avoid using inferior lubricants.

Component replacement: Chains, gears, and brake pads with excessive wear should be replaced in a timely manner; If the wear of the hook exceeds 10% or cracks appear, it should be scrapped immediately.

Cleaning and rust prevention: Clean the dust and debris inside the equipment, and perform rust prevention treatment on metal parts.

Troubleshooting process

First, check the external visible components (such as chains and hooks), and then gradually inspect the internal transmission system.

Power off/lockout: Cut off the power source before troubleshooting and perform the lockout/tagout (LOTO) procedure to ensure safety.

Professional intervention: Complex faults (such as electrical and hydraulic systems) need to be handled by qualified professionals to avoid blind disassembly.

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