an embodiment the operator activates a spring loaded grip 19 that moves a hinged lever 18 that then lifts a toothed lever 15 which hereby is disengaged from a curved rack 17 the curved rack is part of the structural support of the patient immobilisation device and is located on a patient positioning table top 16 or similar equipment a gear 14 transmits the rotation generated by the displacement to the synchronizing axis 9 as follows as long as the operator holds the grip the inclination position can be changed once released hinged lever 18 forces toothed lever 15 back into its locking position onto the curved rack 17 the racks tooth geometry corresponds to a defined step in the inclination for example 1 degree per tooth position with the lock freed i e operator holding grip 19 the synchronization axis 9 cannot be removed because a locking element 22 inserted into a slot 23 of the synchronization axis prevents the axis 39 s sliding movement consequently when the lock is engaged i e grip 19 released the geometry of the locking element 22 clears the slot of the synchronization axis allowing the operator to slide the axis and at the same time it prevents to disengage the lock the.