The motor-pump joints or drag joints have the role of transmitting the motion generated by the electric motor to the pump, filling the space that is created inside the aluminum manifold or logic block. In this regard, it is obvious that there is no coupling when the pump is directly engaged on the motor flange. It is good to make sure during assembly that a minimum tolerance remains between the shafts of the motor, joint and pump and that the three elements are not compressed together. This would cause damage to the motor or pump in a short time (even a short time). The joints are always circular, of different lengths and with recesses or bumps depending on what they need to match.