It has become the backbone of domestic transportation today, but many car owners in China focus their attention on the tractor and overlook the trailer when using the vehicle.

In fact, for the operation of vehicles, trailers and tractors are equally important. So how should a semi-trailer be operated correctly, and what precautions should be taken when using a trailer? After reading this article, I believe you will have a closer understanding of the use of semi-trailers.

Safe operation of semi-trailers

1. Connection between tractor and semi-trailer

1.1. The towing height and size of the towing pin, front turning radius, clearance radius, etc. of the semi-trailer must match the towing vehicle, and inspection should be conducted before connection.

Figure 2-1

1.2. Carefully inspect the working surface of the tractor saddle, the traction pin of the semi-trailer, and the traction skateboard for sand, dust, or other foreign objects, as well as for sufficient lubricating grease.

1.3. Connection between the tractor saddle and the traction pin: see Figure 2-1-2

Figure 2-1-2

Adjust the support legs to match the height of the semi-trailer traction skateboard with the traction saddle. Generally, the center position of the upper plane of the semi-trailer traction skateboard is 10-30mm lower than the traction saddle of the tractor (see Figure 2-1-2). Otherwise, sometimes it not only fails to connect, but also damages the traction seat, traction pin, and related parts.

Operate the locking mechanism of the traction seat (different traction seats, see the tractor user manual for details) to open the locking block and make it in a free state.

When the towing vehicle is reversing, the centerline of the towing vehicle and the semi-trailer should strive to be consistent, and the deviation of the centerline of the two vehicles is limited to less than 40 mm. The angle between the two centerlines is ≤ 5 ° at full load and ≤ 7 ° at no load (see Figure 2-1-3).

Figure 2-1-3

Check whether the locking block of the traction seat has locked the traction pin and whether it is securely locked.

Move the tractor forward slightly and check if the connection is good.

1.4 Air circuit connection

Connect the two air pipe joints (commonly known as handshake) on the tractor to the two air pipe joints on the semi-trailer. At this point, the air supply pipeline of the tractor is connected to the air supply pipeline of the semi-trailer, and the control pipeline of the tractor is connected to the control pipeline of the semi-trailer (note the color of the joint: red is the air supply pipeline, blue is the control pipeline).

After the B air joints are connected to each other, the separation switch of the semi-trailer air circuit connection on the tractor should be turned on to put it in a ventilated state. Otherwise, air cannot be supplied to the semi-trailer braking system, and the braking system cannot work.

Start the engine, observe the pressure gauge in the cab, and increase the pressure in the air reservoirs of the tractor and semi-trailer to the specified pressure (usually 650-750kPa).

Check for air leaks in the air circuit and check if the braking system is working properly.

1.5. Circuit Connection

Insert the cable connection plug of the tractor into the cable connection socket at the front end of the box semi-trailer.

Check if all electrodes are properly connected, confirm if all car lights are working properly, and if necessary, replace the wiring of the electrodes.

2. Cargo carrying of box type vehicles or box type semi-trailers

2.1. In order to ensure the safety of vehicles and personnel during loading, unloading, and transportation of goods, it is strictly prohibited for the goods in the carriage to be loaded or unloaded improperly.

2.2 When loading and unloading goods,