Monthly Maintenance Guide for Scissor Lifts

Monthly Maintenance Guide for Scissor Lifts

I. Core Objectives and Prerequisites for Monthly Maintenance

Objective: Identify wear, leaks, and hidden hazards caused by frequent use within one month, ensure stable operation of the hydraulic, electrical, and braking systems, and ensure the responsiveness and reliability of safety devices to prevent further failures.

Prerequisites: Before maintenance, park the scissor lift truck on a flat, dry surface, turn off the power (electric models) or the engine (fuel models), apply the parking brake, lower the platform to its lowest position, and lock the guardrails.

II. Key Component and System Maintenance Procedures

1. Hydraulic System: Preventing Leaks and Maintaining Pressure

Comprehensive Fluid Inspection and Treatment:

1. Open the hydraulic oil reservoir cap and inspect the oil quality. If the oil is turbid, black (normal is pale yellow/transparent), or contains metal debris, completely replace the hydraulic oil with the same type (refer to the equipment manual for the model, such as ISO VG46) and replace the hydraulic oil filter. If the oil quality is normal, refill to the "MIN-MAX" mark. Before tightening the tank cap, clean any impurities from the seals to prevent leaks.

2. Inspect all hydraulic lines: Inspect each joint and weld along the length of the line. Wipe suspected leaks with a clean paper towel. If the paper towel is stained with oil, replace any worn seals (preferably original parts). Focus on inspecting the scissor cylinder piston rod. If scratches or rust are present, apply anti-rust oil and record the results. Report a repair request if the situation is severe.

Pressure and Function Test:

1. Connect a pressure gauge to the hydraulic pump test port, start the platform with no load, and measure the pressure (must comply with the manual's standards, such as 18-22 MPa). If the pressure is insufficient, adjust the pump pressure regulating valve. If abnormality persists, check for filter blockage or pump wear.

2. Raise the platform to its highest position with no load, hold for 1 minute, and observe the platform's sinking (normally ≤ 5 mm). If it sinks too quickly, check for leaks in the check valve or cylinder, and replace any faulty components promptly.

(II) Electrical System: Anti-Oxidation, Maintaining Continuity

Battery and Wiring Maintenance:

1. Electric Scissor Lifts: Remove the protective cover on the battery terminal. Sand the oxidation layer with sandpaper until the metallic luster is exposed. Apply a thin layer of anti-rust grease. Measure the battery voltage (12.4-12.7V at no load is normal. If the voltage is below 12V, charge for 8-10 hours. If the voltage is still low after two consecutive charges, replace the battery). Inspect the battery casing for bulges and leakage, and clean the battery compartment.

2. Fuel Scissor Lifts: Check the generator wiring for security and test the generated voltage (13.5-14.5V at idle). If the voltage is abnormal, check the generator belt tightness (a 10-15mm deflection when pressed is normal) or replace the generator.

Circuit and Control Inspection:

1. Check the lift handle, travel switch, and emergency stop button: Repeat 3-5 times to confirm they operate smoothly and without any sticking, and that the button indicator light is illuminated. Use a multimeter to check for continuity. If any contact is poor, check for loose wire connectors or damaged insulation, and repair or replace the wires immediately.

2.Test the safety circuit: Trigger the platform guardrail limit switch (gently push the guardrail) to ensure the equipment stops lifting immediately. Check the warning lights and turn signals. If dim or off, replace the bulbs or troubleshoot the circuit.

(III) Braking and Structure: Preventing Wear and Maintaining Stability

Brake System Maintenance:

1. Service Braking: Drive at a low speed (less than 5 km/h) on a flat surface. Gently apply the brake pedal and check the stopping distance (normally ≤ 3 meters). If braking is delayed or the vehicle veers, adjust the brake pad clearance (using the brake adjustment bolt to ensure even contact between the pad and disc). Check the brake fluid level (if it is below the "MIN" line on the reservoir, add DOT3/DOT4 brake fluid; mixing different types is prohibited).

2. Parking Brake: After applying the parking brake, attempt to push the vehicle (it must be immobile). If the parking brake is loose, adjust the parking brake cable tension (tighten the adjustment nut at the bottom of the parking brake to ensure it locks when the brake is applied 1/2 of the way).

Structure and Lubrication Maintenance:

1. Scissor Lift: Inspect the scissor lift arm welds for cracks (focusing on the pin joints). Repair minor cracks with anti-rust paint. Immediately remove the scissor lift from service and report any significant cracks. Apply lithium-based grease to the scissor lift pins, rollers, and hinges (apply only enough to cover the entire surface to avoid excessive contamination). Ensure there is no abnormal noise during lifting.

2.Platform and Tires: Inspect the platform floor for dents and damage, and for loose guardrails. If the floor is deformed, correct or replace it. Clean any stones or metal fragments from the tire (or track) tread. Check tire pressure (refer to the values ​​marked on the door. Solid tires should be inspected for surface wear and replaced if the tread depth is less than 2mm).

(IV) Safety Devices: Calibration and Testing

Level and Overload Protection Calibration:

1. Level Sensor: Park the machine on a level surface. After starting the machine, observe the spirit level. If the level indicates tilt (it should be in the center normally), adjust the sensor using the adjustment screws at the bottom to ensure that the platform automatically alarms and stops lifting if it tilts more than 3°.

2. Overload Protection: Place a heavy object (such as a sandbag) at 110% of the rated load on the platform and attempt to start the lift. The machine should fail to move and alarm. If the protection fails, adjust the overload sensor parameters or replace the sensor.

Emergency Device Testing: Emergency Descent: Disconnect the machine power supply (or turn off the engine), press the emergency descent button, and observe whether the platform descends slowly and smoothly (descent speed ≤ 0.5 m/min). If descent is slow or slow, check the emergency descent oil circuit for blockage and clean or replace the oil circuit components.

(V) Auxiliary Components: Repair Damage and Remove Impurities

Air Conditioning and Cooling: If equipped with air conditioning, test the cooling/heating performance after starting it. Clean the air conditioning filter (pat to remove dust; replace if excessively dirty). Inspect the radiator (fuel-powered models) or cooling fan (electric models), removing dust and debris from the surface to ensure proper heat dissipation and prevent overheating.

Fuel System (fuel-powered models): Check the fuel tank level and refill with the correct fuel grade (e.g., 92# gasoline). Clean impurities from the fuel filter. If the fuel filter has been used for more than three months, replace the fuel filter to prevent impurities from clogging the fuel injectors.

III. Maintenance Records and Follow-up Actions

Fill out the maintenance record form: Record the maintenance date, equipment number, maintenance items (e.g., hydraulic oil change, battery voltage, brake test results), note any abnormalities (e.g., "Slight crack in scissor arm weld, repainted"), sign and confirm, and file. Abnormal handling: If a major fault is found (such as internal leakage in the cylinder or structural cracks), immediately affix a "Do Not Use" sign and contact professional maintenance personnel. Do not disassemble the core components by yourself; minor hidden dangers (such as loose wires) must be repaired on the same day to avoid delays that may cause the fault to expand.