| 摘要 |
<p>Two rectangular ventilation ducts are connected by a flanged joint which has four angle members (26) made of bent strip, permanently attached to each side of each duct. These are locked together by inserting a stack of L shaped plates (41) into each corner at the joint, and a bolt is inserted through a larger hole (44) in the corner of each plate, holding them together. Each vertical face (29, 32) of each angle member has a row of embossed circular depressions (74, 76 etc.) along it, and each arm of the L shaped plates has a row of holes (52) along it, into which the depressions locate, the holes and depressions having the same pitch.</p> |
