Sannolikt är det bultarna enligt file:///C:/Users/mail_000/Downloads/US8240041.pdf som avses. Avsnitt 1 efter figurerna: " The root of the rotor blade, including the finger joints, may be locked into engagement with the rotor blade disk by one or more locking pins. A single rotor blade disk may have
as many as several hundred locking pins." Alltså bultarna för infästning av rotorbladen i rotornavet.