Patent ID: 8210783

Claim:
A threaded fastener comprising: a main body portion; a deformable lip portion extending from the main body portion, the lip portion having radially outer and radially inner surfaces, wherein at least part of both the outer and inner surfaces is inclined relative to a longitudinal axis of the fastener; and a recess formed in the main body portion adjacent the lip portion, the recess shaped to receive at least part of the deformable lip portion when a mating torque is applied to the fastener causing the deformable lip portion to deform; wherein at least part of the inner surface of the lip portion is disposed parallel to the longitudinal axis of the fastener, and wherein a fold line is defined at a junction between the part of the inner surface disposed parallel to the fastener longitudinal axis and a part of the inner surface disposed inclined to the fastener longitudinal axis; and wherein parts of the main body portion located radially outwardly of the lip portion, relative to a longitudinal axis of the fastener, define at least one ramp connected to the lip portions, the at least one ramp being inclined relative to the longitudinal axis.