18 as shown in fig9 the positioning of these nuts 23 also makes it possible to incline the plate 20 by a more or less large angle u03b2 with respect to the vertical axis zz u2032 of the pole 1 it will thus be understood that thanks to this device which is particularly simple to implement the user has the possibility of adjusting the arm 3 in a certain angular amplitude both vertically and horizontally with respect to a reference position such a form of embodiment is particularly advantageous in the case of the device being constituted by a plurality of roofing elements 9 for example two roofing elements as shown in fig1 and 2 or four roofing elements as shown in fig6 and 7 the possible relative positionings of the roofing elements with respect to their reference position are shown in broken lines in fig6 the roofing elements 9 may be constituted by a light frame for example a tubular frame 13 covered with a stretched canvas 14 or on the contrary be constituted by a rigid cover made of a moulded plastics material according to the invention the periphery of the roofing elements is provided with a gutter 25 which is intended to collect the run off water and conduct it towards an evacuation as.