"AM" flexible metal joint
A technical report from NASA's Technical Reports Server, dated 1923, describing a flexible metal pipe joint, with its engineering drawings aimed at engineers and mechanical draftsmen. The single picture shows a cutaway section of a threaded coupling with lettered parts A to D, above three numbered diagrams of a short cylindrical joint with an AM badge bending along a tube, which a designer could use as a clean line-drawing reference for mechanical connectors.
