| 摘要 |
<p>The safety net for preventing workmen falling from roofs is secured to the edge of the roof at a point which is below its centre of gravity. It is made of arcuate elements, one end of which is joined to a support attached to the roofing framework. The elements are interconnected either by a rigid safety frame or by a safety net. It can have a hinged section to increase its effective height.</p> |
