The bolster, being the main component connecting the tractor and semitrailer, is being improved in accordance with the trends of the world auto industry. Judging by the novelties in this field, the active introduction of electronics and automation has already significantly improved safety, simplified maintenance, and in addition, shortened the time required for connecting and disconnecting.
The functionality of the system can be raised to a higher level by installing the pneumatic cylinder of the drive-detachable coupling mechanism. The remote control is carried out from the cabin of the tractor, where the information display is installed. At the command of the driver, the pneumatic actuator automatically releases the coupling before disengaging.
The modern bolster includes a number of important components. This is, above all, a baseplate, a detachable coupling mechanism that senses traction and braking forces together with the attachment device, as well as the flexibility unit. Coupling pair is formed after the pin, attached to the semitrailer, enters the slot of the base plate and is fixed with locking parts hinged on the fingers.
For flexibility of the coupling, the SSA must have three degrees of freedom ensuring the turn of the semitrailer around the vertical axis of the kingpin, rocking in the longitudinal plane forwards and backwards (angle is not less than 11°), and also lateral inclination to the left and to the right (no more than 3°). Two of these conditions are met due to the presence of a transverse axis and “softness” at the fixing points of the base plate. At the same time, special saddle devices with an increased maximum angle of the transverse slope are also manufactured. The expansion of freedom is achieved due to the presence of an additional longitudinal axis. It turns out some kind of cardan joint, which provides other possibilities. Stabilizers are used in more complex designs.
Judging by the trends in the automotive components market, this direction will continue to develop. Similar developments will soon appear in the assortment of other well-known manufacturers.