| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a concrete block for a common wire duct whereby a connection part of a protective pipe inserting a wire can be stored in the concrete block similarly to the protective pipe. SOLUTION: In this concrete block 1, 3, a plate concrete block 1 formed with a groove 2 of semicircular section in one surface and a concrete block 3 formed with a groove 2 of semicircular section in both surfaces are layered, a protective pipe inserting hole of circular section is formed, in this protective pipe inserting hole, a protective pipe 5 is inserted, which must insert an electric wire. Here, partly in the groove 2, a radially spread part 8, 9 is provided, which is formed with a circular hole storing a connection pipe 10 of the protective pipe 5.</p> |
