The apparatus consists of a jib restrained by two chain ties making a triangulated three dimensional structure.
A load is hung from the jib end, and the geometry returned to its unloaded state using a knurled collar before taking the spring balance readings
The bottom of the jib is pivoted to the wall mounted plate and the tie attachment locations can be varied independently at their wall ends.
The jib and both ties are fitted with spring balances so that the internal forces can be measured.
