Retention Tester is apparatus for dynamic test of retention system and retention test.
The retention system of helmets is subjected to a specified dynamic loading to determine its dynamic displacement, residual displacement, and damage to the retention system in order to assess the suitability of the helmet. It is further subjected to a dynamic loading at a tangential line on the rear part of the shell. After the test the inclination of helmet on the head-form is checked for suitability of its retention system.
The JUSTY Apparatus for Dynamic Test of Retention System and Retention Test of helmets consists of a rigid fabricated steel frame fitted with arrangements to carry out either of the two tests.
The arrangement for dynamic test of retention system consists of a stand to hold the helmet by its shell from a hook connected to a screw to raise or lower it. The helmet is mounted over a head-form with initial loading device cum guiding system. A mass of specified weight is allowed to fall on the anvil of the loading device from a specified height. The mass is lifted with the help of a handle and chain arrangement and is held by a catch at the specified height. For dropping the mass, the catch is released and mass drops guided on a rod. The displacement of retention system is measured on a vertical scale.