Oval tube section reduction process - uses deformation on principal axis while maintaining wall thickness

摘要

An oval hollow section is deformed over a terminal length, the longer cross sectional dimensions being reduced whilst the shorter dimension remains constant, and the cross-sectional area also remaining effectively constant. The process may be applied to the longerons(12) of a ladder, providing hand grips over an upper terminal length without impairing the structural properties of the member. The walls of the section are forced in, the direction of the deformative forces coinciding with the principal cross sectional axis.