| 摘要 |
Cable trunking for roadsides, protecting communications and/or power cables, comprises sections of enclosed duct laid end-to-end. Each section comprises an open-topped duct body (10,12,14,16) and a lid (22,24,26,32,34) which is assemblable with the body after the introduction of cables through the top opening of the body. The body comprises a floor (10) and upstanding sidewalls (12,14), upper portions (18,20) of the sidewalls being convergent towards the top opening. The lid comprises laterally-spaced reinforcing bars (32,34) secured beneath a top plate (22), the bars providing for the lid to plug the top opening between uppermost portions (28,30) of the convergent sidewalls. The reinforcing bars (32,34) are secured by a single line of weld permitting them to roll inwardly across the underside of the top plate in an energy-absorbing function should the duct body sidewalls be forced inwards against them. Side flanges (24,26) of the lid are arranged to overlie the uppermost portions of the sidewalls externally. The duct sections are of a shatterproof construction, the body and the lid both being of steel. <IMAGE> <IMAGE>
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