| 摘要 |
<p>Air duct comprises a tubular member, having a first end portion and second end portion, a female ring, affixed to first end portion, a male ring, affixed to second end portion, and having a portion which extends beyond the second end portion and an inner portion which is within the second end portion. The extended portion has an outside diameter less than the internal diameter of the female ring and is inserted into a female ring of another of the ducts, and has one or more projections of greater diameter than the internal diameter of the female ring for engaging a female ring of another duct to prevent its withdrawal from the female ring.</p> |
