| 摘要 |
eam for the construction of greenhouses 11, 16 of a cross section 1, 2 with flattened formations at the edges 3, 5 and intermediately 4 in the form of the formations at the height 7, 8, 9.The connection holes 6 and 10 are opened onto the formations for the connection with the vertical supports 12, 13 and 14.The croos sections 1, 2 of the beams 11, 16 are made from a steel blade of a small thickness and hence low weight. The formations 17 reinforce the beams so that their resistance to bending is increased.The formation 15 facilitates the improved application of the membrane for covering the greenhouse, whereas the formations 17, 18 form a more rigid construction and a more rigid connection.The flexibility of the beams at the desired support points is achieved with the intermediate flatenned formations 4.The size of the beams as well as their material of construction may vary. |
