The present embodiments relate to a lifting unit for a patient support. The lifting unit includes a base plate, a motor drive, a lifting drive driven by the motor drive and received in the base plate. The lifting drive is adapted to carry out a lifting movement and a movement in the opposite direction. A triggering element is activated when the pressure exerted by the lifting drive on the base plate falls below a defined minimum value. The movement of the lifting drive is stopped in response to the activation of the triggering element. If the patient support collides with an obstacle during lifting, the pressure exerted by the lifting drive on the base plate is reduced. The reduced pressure is detected by the triggering element and the movement of the patient support is stopped.