摘要 |
A building system has interlocking frame members which interengage to form a rectilinear frame. To prevent the interengaged frame members from disengaging, a lock element is associated with a joint between frame members. This lock element is a rotary lock with a trilobal locking surface. Additional locking capability can be provided by a lock ring or collar which surrounds a joint between two frame members and prevents unintentional disengagement. |