| 摘要 |
It comprises a horizontal rod (2) uniformly spaced along the length of which are made peripheral grooves (21) in which are fixed, by welding, gripping elements (22) consisting of metal wire twisted in the form of an M with rounded angles (23, 27, 28), the end of the branches (25, 26) of which are provided with folded metal plates (30, 31) welded to the inside of the said branches (25, 26), the ends of the said metal plates (30, 31) being cut out as a reentrant V (38) forming two lateral points (36, 37). <IMAGE> |
