Frangible connectors with independently selectable bending and tension separation loads

摘要

Frangibly connected members and frangible connector inserts for frangibly connecting members, such as self-closing breakaway valve assemblies, provide independently selectable tension and bending separating loads. A frangible connector insert comprises a tension ring having a cylindrical surface closely receiving a moment arm ring having a mating cylindrical surface to establish an axial interface therebetween. Tension-mode frangible screws or pins are disposed across the axial interface, and are preferably evenly arrayed about the tension and moment arm rings. A bending ring is attached to the moment arm ring by bending-mode fragible screws or the like, also preferably evenly arrayed about the bending ring and moment arm ring. The tension and bending rings are attached to members to connect them when provided as a frangible connector insert, or are integral with the members. The tension-mode frangible means break upon application of a given tension load, but do not break upon application of a bending load. The bending-mode frangible screws break upon application of a given bending load, but not upon application of a tension load. Thus, the bending load and tension load at which the frangibly connected members separate are independently selectable. Self-closing breakaway valve assemblies of the type having rotatable valve members spring biased to close upon separation of their respective frangibly connected valve housings use the foregoing frangible connectors or frangible connector inserts.