The present disclosure relates to a shaft tube joint structure of a drive shaft, including an extension tube, a shaft tube, a convex tube, a concave tube, an inner adhesive rubber ring and an outer adhesive rubber ring; the extension tube and the shaft tube are abutted to each other; the convex tube is sleeved in the extension tube and the shaft tube at the abutting position therebetween, an inner seam having a variable gap size distribution is formed in an axis direction; the concave tube is sleeved on the extension tube and the shaft tube at the abutting position therebetween, an outer seam having a variable gap size distribution is formed in the axis direction. The inner adhesive rubber ring and the outer adhesive rubber ring are fully used for simultaneously transmitting a power torque, thus improving the power torque bearing capability of the shaft tube joint structure.

A shaft tube joint structure of a drive shaft is disclosed. The structure includes an extension tube, a shaft tube, a convex tube, a concave tube, an inner adhesive rubber ring and an outer adhesive rubber ring; the extension tube and the shaft tube are abutted to each other; the convex tube is sleeved in the extension tube and the shaft tube at the abutting position therebetween, an inner seam having a variable gap size distribution is formed in an axis direction; the concave tube is sleeved on the extension tube and the shaft tube at the abutting position therebetween, an outer seam having a variable gap size distribution is formed in the axis direction. The inner adhesive rubber ring and the outer adhesive rubber ring are fully used for simultaneously transmitting a power torque, thus improving the power torque bearing capability of the shaft tube joint structure.

A circular sheet metal duct having a sealant applied across the longitudinal seam. The sealant will improve the efficiency and will reduce or eliminate air leakage from the longitudinal seam. The sealant is applied during the manufacturing processes so that an installer does not have to seal the duct work. The method of manufacturing the sealant is provided.

A circular sheet metal duct having a sealant applied across the longitudinal seam. The sealant will improve the efficiency and will reduce or eliminate air leakage from the longitudinal seam. The sealant is applied during the manufacturing processes so that an installer does not have to seal the duct work. The method of manufacturing the sealant is provided.

A manufactured sealed latched sheet metal circular HVAC fitting including a first subcomponent having a HVAC end and a first subcomponent coupling, a second subcomponent having a HVAC end and a second subcomponent coupling, sealant on the first subcomponent or the second subcomponent, and a sealed latched joint created by the connection of the second subcomponent coupling with the first subcomponent coupling, the sealed latched joint using the sealant on the first subcomponent or the second subcomponent as part of the sealed latch joint.