The unit consists of two vertical elements (1) with horizontal stands (2) and two traverse support bars (6). Each of the vertical elements is formed at the bottom and at the top as an inner shaft with a rotating outer case (4) and has a stationary vertical bar (5) positioned between the rotatable or fixed stretches. The traverse bars are fixed to the upper and lower end of the stationary bars. Adjustable disc-shaped feet (7) are attached to the horizontal stands from below.
