Hydraulic Rear Dump Semi Trailer Operation Precautions

Most of the users of flat rear dump semi trailers are converted from ordinary warehouse trailer users. Most of the drivers lack experience in lifting and unloading rear dump vehicles. A great security risk. The following editor will share with you the rear dump semi trailer lifting system and operation precautions.

Composition of rear dump semi trailer hydraulic system

The rear dump semi trailer is mainly composed of a tractor and a semi-trailer. The main vehicle (tractor) is connected with the semi-trailer through a saddle to form a semi-trailer train.

Rear dump semi trailer hydraulic lift system mainly consists of power take-off (gearbox), hydraulic pump, lift valve, air control valve, limit valve, hydraulic cylinder, hydraulic oil tank, high (low) pressure oil pipe, etc.

Rear dump semi trailer hydraulic system principle

The hydraulic lifting principle of the rear dump semi trailer is as follows: the power take-off device of the main vehicle gearbox is operated to drive the hydraulic pump to work. The hydraulic pump sucks the hydraulic oil in the hydraulic oil tank through the low-pressure oil inlet pipe and generates high-pressure oil for output. The high-pressure oil output by the gear pump The high-pressure oil pipe enters the lift valve, and the lift valve delivers high-pressure oil to the oil cylinder or discharges it into the hydraulic oil tank under the control of the air control valve to realize the lifting, stopping and lowering functions of the hydraulic oil cylinder.

Maintenance specification of rear dump semi trailer hydraulic lifting system

1. The new car should be lifted slowly during the running-in period. In principle, the engine speed should be controlled at about 1000 rpm, and it should not exceed 1500 rpm after the running-in period;
2. Due to impurities such as iron filings inside the hydraulic system during the running-in period of the new car, the hydraulic oil should be replaced and the hydraulic oil tank should be cleaned when the new car is lifted about 300 times;
3. The high-pressure oil pipe must be replaced every two years. During the daily maintenance process, if the hose is found to have oil leakage, damage, partial swelling or cracking, it should be replaced in time;
4. Check the hydraulic oil every week for discoloration and deterioration. If there is discoloration and deterioration, it should be replaced in time. The hydraulic oil should be changed according to the region and season. Generally, it is more appropriate to change the oil in April and October. When it is found that the oil is insufficient, it should be replenished in time. The specific area and recommended oil are shown in the figure below;
5. The upper and lower brackets of the oil cylinder need to be injected with grease (butter) in time. It is recommended to inject grease once every 120 times or 15 days when the oil cylinder is lifted, and re-inject grease once before returning to use after long-term use;
6. Check the oil return filter element and air filter element inside the hydraulic oil tank every half a month for clogging and cleaning, and replace the oil return filter element and air filter element of the hydraulic oil tank every six months;

Rear dump semi trailer lifting operation and precautions

Vehicle lifting operation sequence:

1. Open the car tarpaulin or lid
2. Open the rear door lock
3. Depress the clutch with the transmission in neutral and wait 5 seconds
4. combined power take-off
5. Shift to low gear (less than 4th gear)
6. Put the air control valve handle in the up position
7. Release the clutch and the vehicle starts to lift, you can properly step on the engine accelerator but it must be controlled within 1500 rpm
8. When the oil cylinder reaches the maximum stroke or the limit valve works, the handle of the air control valve is in the neutral stop position.

Vehicle lowering operation sequence:

1. Depress the clutch and wait 5 seconds
2. Disengage the power take-off
3. disengage transmission gear
4. release the clutch
5. Slowly turn the air control valve handle from the neutral stop position to the lowering position (the air control valve of the hydraulic lifting system of the Universiade dump truck is a proportional control valve, which can control the lowering speed of the oil cylinder. The closer the handle is to the lowering position, the faster the lowering speed of the oil cylinder will be. quick)
6. Wait for 30 seconds after the car body is completely lowered, and put the handle of the air control valve in the middle stop position.

Rear dump semi trailer lifting operation precautions

• The rear dump semi trailer hydraulic cylinder is a special cylinder for lifting, and it is strictly forbidden to use the cylinder as a stable support for the car body;
• Under the lifting state, the oil cylinder should not be exposed to the air for more than 2 hours (not more than 30 minutes in humid air), otherwise the cylinder barrel will be oxidized and rusted;
• It is strictly forbidden to disassemble and adjust the relief valve on the lift valve, otherwise the hydraulic system will lose its safety protection function and cause an accident;
• When the vehicle is loaded with goods, ensure that the front, rear and left and right are loaded evenly. If the goods are loaded too far forward, the hydraulic system will be overloaded. If the goods are loaded too far behind, the vehicle will turn over when unloading.
• When unloading the vehicle, it is necessary to ensure that the unloading ground where the vehicle is located is solid and flat, the vehicle is kept level and the main vehicle and the trailer are in a straight line;
• During the lifting operation, the operator cannot leave the operating position, and no one is allowed to stand or walk near the working area;
• During the lifting operation, the operator must pay attention to the influence of the lateral wind, because the force of the long side wind on the surface of the dump truck body will cause the vehicle to roll over;
• The cargo loaded on the vehicle should not be higher than the rear door (unless it can be guaranteed that it will not block the rear door) and the rear door locking device must be opened before lifting and unloading, otherwise the cargo will be crowded at the rear of the vehicle during unloading and the vehicle will overturn;
• When unloading at a temperature below 0 degrees, be sure to pay attention to whether the cargo is frozen, otherwise the vehicle will roll over due to left-right imbalance when unloading;
• Do not move the vehicle while the carriage is lifted, and do not use sudden braking to unload sticky goods, otherwise it will cause the vehicle to roll over or damage the oil cylinder;
• If the lifting angle of the car body reaches about 25 degrees (the car body has been lifted halfway), but the cargo in the car body has not been unloaded, please stop lifting and check the cause of sticking;
• If you have a premonition that rollover may occur during lifting, please stop lifting and lower the car body slowly;
• After the car body has completely fallen and waited for about 30 seconds, be sure to put the handle of the air control valve in the middle stop position. Do not start the vehicle in the lowered position, so as to avoid the hydraulic oil in the hydraulic cylinder from flowing back into the hydraulic oil tank, causing cavitation of the cylinder and fuel injection problems in the fuel tank. ;
• When the vehicle needs to be lifted for repair or maintenance, etc., please ensure that the vehicle is safely supported. Working under a box that is not safely supported will be life-threatening.

Summary:

The above is the composition of rear dump semi trailer hydraulic lifting system and precautions for lifting operation shared with you this time. Everyone must follow the regular operating procedures during daily maintenance and operation. If you have any questions or help, please call the panda rear dump semi trailer manufacturer for consultation.