shaft 25 1 and thus the common single drive motor 32 would be obtained the belts can have various marketable profiles and could be made either as endless belts or belt portions connected to each other at their ends the blowers can be also arranged differently for example on the horizontal holding bar which would be rotationally supported at one of its ends about the vertical axis whereby the shafts of the blowers would extend parallel to the axis of rotation of the holding bar fig4 to 6 illustrate the embodiments with differently arranged or formed drive motors in the embodiment of fig4 the drive motor 32 39 is secured to the radial arm 20 of the holding bar 19 and also is rotated with the holding bar 19 the lower belt pulley 26 1 is coupled directly with the output shaft of the electric motor 32 39 whereas the drive of the radial arm 20 is carried out via transmission or gearing 33 39 and a bevel gearing 36 which is supported on shaft 38 supported in a bearing box 37 and connected to the radial arm 20 contact tracks are provided on the bearing box 37 rotating brushes 39 transfer current from contact tracks on bearing box 37 for the electric motor 32 39 in the embodiment of fig5 blowers 24 are driven by a common motor 40 which is secured to the radial arm 20 and which drives the lower belt pulley 26 1 a separate.