| 摘要 |
K 9 Pa 80/1 A trench supporting apparatus with steel plates for supporting the sides of the trench has upright support structures between the plates, the uprights having guides for taking up the edges of the plates. The guides have rollers with axes parallel to the planes of the plates for the purpose of decreasing friction between the plates and the support structures. The guides may be in the form of bars with spaces between them in which the rollers are placed, the diameters of the rollers being such that the rollers are proud of the bars of the guide. |
