Various systems are presently in use to assist in securing the mating edges of a pair of ducts together to form a joint between the pair of ducts. One such application is in commercial aircraft construction where an AS1895 clamp and AS1895 (Aerospace Standard) clamp ring are used to join a pair of ducts that are being used to provide fluid pressure to a pneumatic subsystem of the aircraft. In such an application, failure of the AS1895 clamp or the AS1895 clamp ring would allow the joined edges of a pair of ducts to separate to a significant degree, resulting in a core cavity pressure spike. Another detriment in such an event is that surrounding structure is exposed to high temperature pneumatic air. Aircraft designers must compensate for this rare event by adding material to the various portions of the aircraft (typically cowling or fairing structures) that are closely adjacent the joined areas of duct work being used to supply pressurized air to an aircraft subsystem. As a result, aircraft designers address the rare event of joint failure of a pneumatic duct by increasing the material thickness of the aircraft component (e.g., fairing, cowling, etc.) to a sufficient degree such that damage to the aircraft component will not result if a joint failure of the pressurized duct occurs. As will be appreciated, the use of materials having additional thicknesses can add appreciably to the cost and overall weight of a commercial aircraft.
Accordingly, there exists a need for a coupling apparatus that can be used to couple the ends of a pair of ducts of a pressurized duct assembly, and which assists in maintaining the joined ends of the duct in close proximity to one another in the rare event of a failure of a primary clamp assembly being used to hold the ends of the two ducts in joined relation. Such an apparatus and method would ideally be integratable with an existing AS1895 clamp and AS 1895 clamp ring in a manner that does not materially complicate the overall joint construction nor complicate the assembly of the overall duct. Still further, such an apparatus and method would ideally permit a controlled degree of separation of the ends of the two ducts being joined in the rare event of a failure of the primary clamp joining the ducts, to thus allow external sensors to be used to detect that the joint has failed. Such a controlled degree of separation, however, would limit resulting peak core cavity pressure and ensure that the previously joined ends of the duct do not come into contact with any other panels or components of the aircraft.
USPTO Backgrounds
USPTO Backgrounds