Please strictly adhere to all scheduled maintenance, adjustment, and inspection tasks outlined in the operating manual. This includes all prescribed intervals and specific guidelines for component and equipment replacement. Such tasks must be executed exclusively by qualified and authorized specialist personnel with proven expertise in electric-hydraulic systems.
Pre-Work Preparation and Shutdown Protocol
Before initiating any maintenance or servicing activities, the responsible operations staff must be clearly informed and the work plan coordinated with them. A designated supervisor must be appointed to oversee the entire process and ensure compliance with safety standards.
During all phases of assembly, disassembly, commissioning, operation, maintenance, and repair, the shutdown procedures as defined in the operating instructions must be strictly followed.
Before commencing any maintenance or repair, the electric-hydraulic grab bucket must be completely de-energized and secured against any inadvertent or unauthorized restart. This is achieved by disconnecting the main power plug wherever feasible.
Only after the machine has been completely shut down and locked out may any protective covers or guards be removed.
Work Environment and Safety Precautions
All repair operations on the hydraulic and electrical systems of the electric-hydraulic grab must be carried out in a clean, dry, and dust-free environment to prevent contamination and ensure system integrity.
If the situation requires, the immediate work area must be cordoned off and clearly marked to restrict access and prevent hazards.
For work performed at elevation, only safety-compliant ladders and certified work platforms shall be used. Never use machine components (e.g., hoses, cylinders) as steps. Personnel must wear appropriate fall-arrest protection of the electric-hydraulic grab at all times.
As contact with hot surfaces and unintended oil discharge cannot be entirely ruled out, safety goggles and protective gloves are mandatory throughout all maintenance and repair procedures.
Lifting and Handling Procedures
When replacing spare parts or modules, ensure they are securely attached to lifting gear using suitable and technically flawless equipment with adequate load capacity. All loads must be carefully balanced to prevent shifting or falling.
Under no circumstances shall any person stand or work beneath suspended loads.
Hydraulic and Electrical System Care
Safety Procedures for Cleaning Electrical Equipment
All cleaning operations involving electrical components must be performed while the equipment is completely de-energized. Before commencing work, electrical plugs must be disconnected to ensure a total power cutoff. This requirement applies equally to non-contact cleaning methods (such as compressed air purging); no exceptions are permitted for any reason. The use of damp or conductive media during cleaning must be avoided to prevent equipment damage or personal injury caused by residual charges or accidental electrical conduction.
Management of Pressure Control and Safety Protection Devices
It is strictly prohibited to short-circuit, bypass, or disable pressure switches, pressure control valves, safety relief valves, or other sensing and monitoring devices in any manner. These components of the electric-hydraulic grab serve as critical safety barriers for the system; their functional integrity and preset parameters must not be altered arbitrarily. Any adjustment or recalibration of these safety devices requires prior written authorization from the manufacturer and must be carried out in strict accordance with the manufacturer's technical specifications and operational procedures.
Requirements for Safety Valve Replacement
When a safety relief valve is damaged or reaches the end of its service life, it may only be replaced with an original valve-or a manufacturer-approved equivalent-that matches the original in model, specifications, pressure rating, and performance parameters. The use of substitute models or uncertified imitation parts is prohibited to ensure the reliability and consistency of the system's overpressure protection function.
Inspection and Replacement of Lines, Cables, and Valves
If visible mechanical damage (such as cracks, indentations, or twisting), excessive wear, aging/cracking, fluid leakage, or insulation damage is detected in hydraulic hoses, rigid hydraulic lines, power cables, or valves, use must be discontinued immediately, and the components must be replaced. Furthermore, even in the absence of apparent defects, hydraulic hoses should be replaced at the intervals recommended in the operation manual (refer to the "Hydraulic Hose Assembly Inspection Procedure") to prevent sudden failure caused by material fatigue or internal aging.
Fastener Torque Management
When tightening threaded connections, the torque values specified in the operation manual must be strictly observed, and torque spot-checks should be performed periodically. During maintenance or repair, any bolts, nuts, or other fasteners that have been loosened must be securely retightened to the specified values during reassembly using calibrated torque tools, in accordance with current technical specifications or torque charts; tightening based on experience or "feel" is prohibited to prevent connection failure or component damage resulting from insufficient or excessive preload.
Cleaning Restrictions and Component Protection
Before cleaning the electric-hydraulic grab bucket with water, steam, high-pressure washing equipment, or chemical detergents, all openings through which moisture or cleaning agents could penetrate-such as electric motors, control cabinets, limit switches, bearings, gears, and chains-must be securely covered or sealed to prevent functional damage or safety hazards.
Post-Maintenance Inspection and Recommissioning
Regularly inspect all electrical cabling and hydraulic oil lines for signs of physical damage, abrasion, leaks, or deterioration.
Following the completion of any maintenance or repair work, prior to restarting the electro-hydraulic grab bucket, carry out a thorough verification that all safety equipment has been reinstalled correctly and is fully operational. Furthermore, perform a comprehensive functional test of the grab bucket, including verification of the correct working pressure and all control movements, to ensure safe and reliable operation.
