| 摘要 |
1420269 Marking buried pipes PLYMOUTH FRANCAISE 30 March 1973 [16 June 1972] 15325/73 Heading F2P [Also in Divisions H2 and D1] An article for marking the position of underground pipes or cables comprises at least two members 2, 3 which exhibit different breaking strengths and different elongations at rupture. In one embodiment, as shown, a twisted metal structure 2 coated with plastics also has two wires 3 incorporated in manufacture. In another embodiment, two longitudinal strips (5) (Fig. 2, not shown) are included in a welded plastics lattice (4). When the shovel of a mechanical excavator ruptures the article pieces of the article structure are elongated and extend through the trench wall to give a visible mark of the pipe or cable position. |
