Self-locking nut with connected end segment - using shear neck which breaks when predetermined torque is reached

摘要

The self-locking unit is of the usual hexagonal form but has a deep and narrow circumferential groove (4) at approximately half-way along its thickness. This divides the nut into two segments (1, 2) connected by neck (3) of a predetermined torsional strength. The nut is tightened by applying a spanner to the outer end (2) which is sheared at the required torque. The outer end is still further tightened so that an additional tension is imposed on the bolt and at the same time the irregularities of the sheared surfaces lock the two parts together.