Torque Tube Hirth Coupling for Mistake-Proof Vane Alignment

The patent applies asymmetry by implementing a Hirth tooth coupling pattern where teeth are asymmetrically distributed around the coupling interface. This asymmetric tooth arrangement ensures that only one specific rotational position allows proper engagement between the torque tube and bell crank, eliminating the misalignment issues caused by symmetric flat alignment features. The asymmetric geometry provides inherent alignment guidance during assembly.

The Hirth tooth coupling implements self-service by providing inherent alignment verification through its meshing tooth geometry. The coupling design ensures that proper engagement of the teeth automatically indicates correct alignment, eliminating the need for separate alignment features that could provide false feedback. The system self-verifies its own correct assembly through the mechanical interlocking of the asymmetric tooth pattern.

The Hirth tooth coupling provides immediate feedback through its meshing tooth mechanism. When the torque tube is correctly aligned, the teeth engage smoothly and uniformly. When misaligned, the asymmetric tooth pattern prevents proper engagement, creating noticeable mechanical resistance or preventing assembly entirely. This immediate tactile and mechanical feedback allows operators to detect alignment issues during the assembly process itself, before damage occurs.

The Hirth tooth coupling implements preliminary action by establishing correct alignment through the meshing tooth geometry before any fastening or torquing operations are performed. The asymmetric tooth pattern pre-determines the correct rotational position, ensuring that when fasteners are subsequently installed and torqued, they are already in the correct position. This eliminates the scenario where fasteners shear through misaligned holes, as the alignment is predetermined by the tooth engagement.