News & Insights
Company news, exhibitions and practical notes on running and maintaining material handlers.
Troubleshooting Weak Gripping Force in Log GrapplesLog grapples use hydraulic drives for clamping and handling and are commonly used in mountainous regions, forestry sites and similar environments. Many log grapples are converted from excavators to meet long-term professional needs; after conversion they handle cargo more adaptably, work considerably more efficiently and operate more safely.
A machine depends on several systems working together, and a problem in any one of them can reduce overall performance. For weak gripping force, the following troubleshooting steps are recommended.
1. Check the hydraulic oil and filters
Check that the hydraulic oil level meets specifications, that the filter element is not clogged and that the oil brand meets requirements. Correct any non-compliant items first.
2. Monitor oil temperature
Monitor the oil temperature during operation. If the oil overheats, inspect the hydraulic oil cooling system to find and eliminate the cause.
3. Measure working pressure
Measure the working pressure at the weak function and compare it with the standard values.
4. Avoid hasty part replacement
Once a faulty component has been identified, do not rush to replace it. Some parts may be undamaged and reusable after cleaning; others can be repaired. Consider carefully whether replacement will actually eliminate the root cause.
5. Clean the whole system
Metal debris may have accumulated throughout the system, including the hydraulic oil tank. If it is not cleaned out, it can cause repeated damage. Before replacing components, thoroughly clean the hydraulic system and oil tank, and replace both the hydraulic oil and the filter elements.
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Common Rust Prevention Methods for Dock Crane BearingsBearings are critical components in dock cranes and other construction machinery. Their condition directly affects operating efficiency, service life and even safety. Besides wear, corrosion is a major challenge, so preventing bearing rust requires consistent attention and the right rust prevention measures.
Surface cleaning: choose the cleaning method according to the nature of the surface and the conditions at hand.
Surface drying: after thorough cleaning, dry the surfaces with filtered, dry compressed air.
Immersion: small parts can be immersed in rust-preventive grease so that a protective layer adheres to the surface.
Brushing: when applying by brush, avoid excessive buildup and make sure coverage is complete, with no missed areas.
Spraying: suitable for solvent-diluted or thin-film rust-preventive oils, but requires thorough fire prevention and personal protection measures.
Whichever method is used, choose the most suitable approach for the specific situation. Once the conditions needed for rust to form are eliminated, rust prevention is no longer a challenge.
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How to Maintain and Service a Wheeled Log LoaderAfter taking delivery of a new log loader, read the operator's manual carefully before operating the machine and follow its instructions for use and handling. Pay particular attention to the following points.
Always give priority to air filter maintenance.
Use fuel that matches the machine's specifications.
Replace the hydraulic oil at 2,000 hours, followed by the transmission oil, swing gear oil, engine oil, hydraulic oil inlet and return filters, pilot filters, oil filters, diesel filters and oil-water separators. Apply grease daily, check oil levels regularly and check coolant levels as needed.
Keep lubricants clean and sufficient, replace them periodically, and use the grades specified in the manual.
Take care when adding coolant, and never run the engine with a low coolant level. If the coolant level is low, top it up promptly once the engine has cooled.
On a new grapple, the engine oil and all filter elements should normally be replaced within the first 50 hours; the gear oil and hydraulic oil can be replaced later. Service the diesel air filter and engine filters regularly, replace them as needed, and grease the machine daily.
Maintenance is divided into sections, such as the engine, the hydraulic system and the grab frame, each carried out according to the relevant manual or specification. It involves lubricating, cleaning and inspecting each component. Keep the grapple's oils clean and lubricate the rotating shafts. After 1,000 hours, replace the main transmission gear oil, engine oil, oil filter elements, diesel filter elements, oil-water separators, hydraulic oil inlet and return filter elements, and pilot filter elements.
Inspect and tighten all relevant bolts and nuts, especially connecting rod bolts, drive shaft bolts, flywheel lock nuts and wheel nuts.
Before adding oil, make sure it has settled and been filtered. The oil filling equipment must be clean and free of contaminants.
Before operating, inspect the hydraulic oil tank and the fuel tank and check for any basic maintenance needs.
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Electrical Safety Devices on Dock CranesOn lifting equipment such as dock cranes, the electrical system is a critical component, and its condition directly affects how the crane works. To ensure normal operation and personal safety, electrical safety devices are installed to prevent malfunctions and control accidents. The main devices are listed below.
Torque limiter: stops operation when the load exceeds the rated capacity.
Zero-position interlock: prevents equipment damage or personal injury caused by a motor starting by itself.
Limit interlock: limit switches on the travel or hoisting mechanisms cut the power and stop the motor.
Limit protection: prevents mechanical components from moving beyond their end positions.
Overspeed protection: prevents the load from falling when the motor speed exceeds the specified limit.
Main isolation switch: disconnects all power sources.
Protection box: allows the operator to quickly switch off the main power in an emergency.
To maximize safety, all of these electrical safety devices should be installed. Although they are only a small part of the systems on a dock crane or other large machine, their importance should not be underestimated. Keep them in good working condition and protect them from damage.
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Key Features of the Steel GrabberThe steel grabber uses an axial piston hydraulic pump with a constant-power control system, making full use of the motor's output while minimizing energy loss. Its remote-controlled electrical system makes the machine easier to operate and monitor and improves coordination with the grabber's movements, raising overall efficiency.
Reinforced working equipment developed for real site conditions, meeting the requirements of machinery plants.
Mechatronic control system.
Bionic design that mimics the movements of the human hand for intuitive operation.
Exterior design based on structural concepts widely used internationally.
A high degree of standardization makes spare parts easy to replace, and the modular design simplifies maintenance and servicing.
Applications
The wheeled steel grabber is a versatile material handling machine. Its main job is grabbing and loading materials such as scrap metal, scrap steel, finished steel bars, industrial waste, crushed stone, construction debris and municipal waste. It is widely used in scrap recycling plants, steel mills, metallurgical plants, ports and docks, and scrap steel processing centers.
Steel grabber vs. standard excavator
The main difference between a steel grabber and a standard excavator lies in the front working equipment and its purpose. A standard excavator usually has a shorter boom and arm with a bucket and is designed mainly for digging and loading; its structure also differs. The standard configuration of a steel grabber is a straight boom with a curved stick, and straight boom with straight stick or curved boom with curved stick versions can be built to customer requirements.
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Storage Guidelines for Wheeled Grapple MachinesBefore storage
Before storing the grapple machine, apply sufficient grease and keep it in a dry place. Grease any rusted areas as well, since humidity and temperature changes can cause rust and corrosion.
If the hoses stay connected, seal the hose openings with plugs. If they are disconnected, cap the openings to prevent hydraulic oil leaks or contamination.
Rest the grapple on wooden boards that are strong and large enough to support it. When disconnecting hydraulic hoses, check for oil leaks and dispose of waste oil according to regulations.
Long-term storage precautions
Clean and dry all components and store them in a well-ventilated place.
Clean at least once a month and lubricate moving parts.
Apply grease to cylinder rods and other areas prone to rust.
Daily inspection points
Check the body for damage or deformation.
Inspect pins and bushings for damage and decide when they need replacing.
Make sure bolts and nuts are properly tightened.
Routine inspection points
Rotating components wear and should be replaced promptly when they reach the end of their service life. Use genuine OEM parts for replacement.
Inspect the rotating shaft. It must turn freely through 360 degrees so the grapple can work precisely at any angle. Make sure it is adequately lubricated and its bolts are properly tightened.
Check bolt tightness. Check new bolts after 8 hours of operation to make sure they have not loosened, and replace damaged bolts immediately. Bolts should be replaced after about 1,500 hours of use or 12 months after installation.
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Log Grapple Operation in the Rainy Season: Common IssuesOperating in the rainy season
Before starting work, carefully assess the surroundings and check the site for soft ground or other hazards. A common method is to push a bamboo pole into the ground by hand: if it goes down easily at several points and meets no resistance within the first meter, the whole area is muddy. Log grapples often sink in such mud, making normal work impossible.
Before working in mountainous areas during the rainy season, inspect the work area for landslides, collapses or slope failures. Look for signs such as damaged slopes, improper foundation excavation, poorly disposed soil or slag, dense vegetation and muddy water running off the hillside.
If the machine starts to sink during operation, stop work immediately. Use the arm to find a firm support point and prevent further sinking, then withdraw the machine backward the same way, without moving in any other direction.
Stay alert when working in the rain. On night shifts, make sure all lights on the machine (front and rear lights, work lights, headlights and instrument lights) and the windshield wipers work properly.
After work, always park the machine on high ground away from residential areas. Avoid hazardous places such as slopes prone to collapse and riverbanks. Leave enough space for refueling, and make sure the machine can be started and moved out immediately.
Storage in the rainy season
If possible, store the machine in a dry indoor location and clean off all dirt thoroughly.
When parking outdoors, make sure the diesel tank cap and the hydraulic oil filter cover are securely closed to keep sediment out of the tanks.
Inspect the machine, repair worn parts and fit new components as needed.
Clean the main air filter element and all lubrication points. Retract all hydraulic cylinders; if that is not possible, grease the exposed cylinder rods. Then rest the tracks on long, flat protective blocks.
Once the battery is fully charged, remove it and store it in a dry place. If it is not removed, turn off the power switch or disconnect the negative battery cable.
Check the seal ring on the engine oil dipstick for wear, which could let sediment into the engine oil. Also check the fuel filler; when parking outdoors, cover it with a protective bag if necessary.
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Projects by country and model
Not sure which machine fits? Compare models in the selection guide or send your working conditions for a selection plan.Read more Get a selection plan
Tell us about your material, site and output. Our engineers will recommend a machine type, configuration and grab, then send a quotation.
- Share your working conditionsMaterial, throughput, site and power supply
- Receive a recommended configurationChassis, power, reach and grab matched to the job
- Get a quotationBased on the configuration agreed with you
WhatsApp · Mr. Xu Fuyuan+86 184 3829 6999
YONGGONGHenan Huanghai Heavy Equipment Manufacturing Co., Ltd. — rail-mounted, crawler, wheeled and stationary material handlers since 1992.
Get a selection plan
Tell us about your material, site and output. Our engineers will recommend a machine type, configuration and grab, then send a quotation.
Prefer to talk? WhatsApp +86 184 3829 6999 or henanyonggong@163.com