Method and apparatus for adjusting mutual position of constructional elements of a patient chair

The object of the invention is a method and an apparatus for adjusting mutual position of two structural elements of a patient chair, like the back rest and the head rest, articulated with each other, in which method the mutual position of the two structural elements connected with each other by articulation is adjusted by a drive device. With the help of the drive device it is possible to produce, for example, an essentially high rotational motion that can be converted to a linear motion with the help of a thread. The linear motion is converted to an essentially slow rotational motion with the help of a thread element functionally connected to an articulated shaft belonging to the position adjustment mechanism.