| 摘要 |
<p>This shaping element is designed to form a sewer pipe receiving opening during pouring of concrete to mound a manhole. The shaping element also holds a gasket seal in position until the concrete has set. The shaping element is made of two axially separable parts each having a flange to form part of the sewer pipe receiving opening. The inner end of one flange has an Lshaped extension defining a radially-inwardly-extending step and an axially-extending end portion, the inner end of the other part extends short of the step and overlaps the axial extension whereby there is formed a gasket seal receiving peripheral channel of L-shaped cross-section. The two parts are completely closed at their outer ends and are assembled by means of noncircular telescopic tubes at their center to maintain the same in a predetermined relative orientation.</p> |
