As a lightweight and small lifting equipment in the industrial field that relies on compressed air drive, pneumatic hoists face multiple challenges in terms of efficiency and safety during frequent use. Based on industry practice and fault cases, the operational faults can be classified into four categories: power system, mechanical transmission, operation control, and environmental adaptation. The following analysis will focus on the fault mechanism, diagnostic methods, and improvement strategies.

1、 Power system failure: core issues of air source and motor

Stall and insufficient power

Unstable gas source is the primary cause, manifested as pressure fluctuations, excessive impurities, or incorrect gas types (such as the risk of explosion caused by the use of flammable gases such as oxygen and hydrogen). In a case of a certain automobile manufacturing plant, due to excessive oil content in compressed air, oil stains adhered to the blades of the pneumatic motor, resulting in a 30% decrease in rotational speed. Improvement requires configuring a three-level filtration system (with an accuracy of 5 μ m) and regularly testing the quality of the gas source.

Internal faults in motors are also common, such as single acting blade jamming and bearing wear leading to transmission failure. The Tiktok maintenance video shows that the back pressure of a certain equipment increases due to the blockage of the silencer, the motor blade is stuck in dry grinding, and the speed is recovered after cleaning. It is recommended to check the oil level of the oil injector every 500 hours, use ISO VG32 pneumatic tool oil, and replace the motor blades every 2000 hours.

Brake system failure

Brake pad wear or air leakage can cause braking delay. In a logistics warehouse case, the thickness of the brake disc was reduced to 1.5mm (original factory standard 3mm), causing a heavy object sliding accident. Improvement requires quarterly measurement of brake pad thickness, soap water coating method for air path sealing testing, and a leakage rate of ≤ 0.1MPa/min.

2、 Mechanical transmission failure: Loss of rotating and reciprocating components

Rotating part stuck

The planetary gear system and bearings are high-frequency fault points. Due to damage to the gear shaft end of a certain steel plant equipment, the transmission ratio deviation was 15%, causing chain teeth to jump. Improvement requires the use of SKF or NSK high-precision bearings, with gear mesh clearance controlled at 0.1-0.3mm, and molybdenum disulfide grease added every 1000 hours.

The reciprocating mechanism is powerless

The wear of piston rings and cylinder blocks leads to a decrease in compression efficiency. In a shipyard case, the cylinder inner diameter exceeded the tolerance by 0.5mm, resulting in a 20% decrease in output force. Improvement requires the use of chrome plated cylinder blocks, with piston ring opening clearance controlled at 0.2-0.4mm, and O-ring replacement every 800 hours.

3、 Operation control failure: reliability of handle and switch

Control handle malfunction

Trigger spring fatigue or steel ball air valve jamming causes command delay. A certain electronic factory equipment caused misoperation due to poor contact of the handle micro switch. Improvement requires the use of Omron or Schneider high life switches, with contact life ≥ 1 million times, and replacement of handle grease every six months.

Drift of the gas regulating valve gear

The wear of the positioning steel ball resulted in the gear not being fixed. In a case of a certain automobile production line, the series movement of the reversing valve caused the chain to run in reverse. Improvement requires the use of Hawley or Rexroth proportional valves, with a gear repeatability accuracy of ≤ 0.5%, and air pressure calibration every 1500 hours.

4、 Environmental adaptation failure: usage conditions and maintenance specifications

**Gas type error

The use of non air media such as nitrogen and liquefied petroleum gas can cause explosions. In a certain chemical plant case, the accidental connection of acetylene gas caused the motor to explode. Improvement requires installing gas recognition sensors at the air inlet and setting color markings (blue for air and red for combustible gas).

Overloading and operational violations

Overloading protection failure or rope entanglement can cause structural damage. In a certain wind farm case, overloading by 20% resulted in chain breakage. Improvement requires configuring force limiters (set value ≤ 110% of rated load) and training operators on the "three no's principle": no diagonal pulling, no overloading, and no unmanned operation.

5、 Improvement suggestion: Systematic maintenance strategy

Preventive maintenance system

Establish a "five fixed" system: fixed point (gas source processing unit), fixed quality (ISO VG32 oil), fixed quantity (oil injector scale), regular (minor repairs every 200 hours), and fixed personnel (full-time maintenance personnel). After the implementation of a nuclear power plant, the equipment failure rate decreased by 65%.

Digital monitoring technology

Deploy vibration sensors (collection frequency ≥ 10kHz) and air pressure transmitters (accuracy ± 0.5%), and analyze motor speed, brake pressure, and other parameters in real time through PLC. In a case study of a certain automobile factory, the system provided a 3-day advance warning for bearing failures to avoid unplanned shutdowns.

Optimization of spare parts management

Using the ABC classification method: Class A (motor blades, brake pads) inventory ≥ 3 sets, Class B (O-rings, gears) ≥ 2 sets, and Class C (bolts, gaskets) purchased on demand. A logistics company has increased spare parts turnover by 40% through this method.

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