초록 ▼

A sheet-metal elbow is coupled by direct attachment to a flat sheet-metal air inlet panel of an air distribution boot or register box by roll-formed flange portions that are mated in interlocking, overlapping engagement with each other. The air inlet panel includes an outwardly flared coupling flang

A sheet-metal elbow is coupled by direct attachment to a flat sheet-metal air inlet panel of an air distribution boot or register box by roll-formed flange portions that are mated in interlocking, overlapping engagement with each other. The air inlet panel includes an outwardly flared coupling flange bordering an air inlet opening. The neck of the sheet-metal elbow includes a folded coupling flange that is dimensioned for interfitting, overlapping engagement with the outwardly flared elbow coupling flange. The coupling flanges are clasped together by a hydraulic ram that drives an expandable mandrel into a V-shaped die cavity. The tightly clasped, overlapping flange portions permit smooth, continuous rotation of the elbow through 360.degree. with respect to the register box for alignment with a branch conduit. The interlocked flanges also provide a strong mechanical union that is virtually leak-free under normal ventilation air flow conditions.

대표청구항 ▼

[ I claim:] [1.] In a ventilation air distribution system of the type including a main distribution duct and a branch conduit coupled to the main distribution duct for delivering pressurized ventilation air into an air distribution outlet box, the improvement comprising a sheet-metal elbow attached

[ I claim:] [1.] In a ventilation air distribution system of the type including a main distribution duct and a branch conduit coupled to the main distribution duct for delivering pressurized ventilation air into an air distribution outlet box, the improvement comprising a sheet-metal elbow attached to a sheet-metal air inlet panel portion of the air distribution box, the elbow including a tubular sidewall coupled for rotational movement on the air inlet panel portion by overlapping flange members formed on the inlet panel portion and elbow sidewall, respectively, the overlapping flange members forming a generally V-shaped union which projects outwardly from the bore of the tubular sidewall, and the inlet panel flange member being disposed radially inwardly of the elbow sidewall flange member.