1. The semi-trailer's towing height, towing pin size, front slewing radius, clearance radius, etc. must match those of the towing vehicle and should be checked before connection.
Picture 2-1-1
2. Carefully check whether there is sand, dust or other foreign matter on the working surface of the saddle of the tractor and the towing pin and towing slide of the semi-trailer, and whether there is enough lubricating grease.
3. Connection between tractor saddle and traction pin: See Figure 2-1-2
Picture 2-1-2
(1) Adjust the support legs so that the semi-trailer traction slide plate is in accordance with the traction saddle height. Generally, the semi-trailer traction slide plate is 10 to 30 mm lower than the center position of the upper plane of the traction saddle of the tractor (see Figure 2-1-2). Otherwise, not only will the connection fail, but the traction seat, traction pin and related parts will also be damaged.
(2) Operate the traction seat locking mechanism (the traction seat is different, see the tractor manual for details) to open the locking block and make it free.
(3) When the tractor is reversing, the center lines of the tractor and the semi-trailer should be kept consistent, and the center line deviation of the two vehicles should be limited to less than 40 mm. The angle between the two center lines is ≤5° when fully loaded and ≤7° when unloaded (see Figure 2-1-3 below)
Picture 2-1-3
(4) Check whether the locking block of the traction seat has locked the traction pin and whether it is locked securely.
(5) Move the tractor forward slightly to check whether the connection is in good condition.
4. Air connection
(1) Connect the two air pipe joints (commonly known as handshakes) on the tractor to the two air pipe joints on the semi-trailer. At this time, the air supply line of the tractor is connected to the air supply line of the semi-trailer, and the control line of the tractor is connected to the control line of the semi-trailer (note the color of the joints: red is the air supply line, blue is the control line).
(2) After the air joints are connected to each other, turn on the semi-trailer air connection disconnector on the tractor to put it in a ventilated state, otherwise it cannot supply air to the semi-trailer brake system and the brake system cannot work.
(3) Start the engine, observe the air pressure gauge in the cab, and increase the pressure in the tractor and semi-trailer air tanks to the specified pressure (generally 650-750kPa).
(4) Check whether there is any leakage in the air line and check whether the brake system is working properly.
5. Circuit connection
(1) Insert the cable connection plug of the tractor into the cable connection socket at the front end of the van semi-trailer.
(2) Check whether each electrode is well connected and whether each headlight is working properly. If necessary, replace the electrode wiring.