EM-231 | Three Wire Suspension Apparatus

A free standing backboard provides supports for three tensile suspenders that meet at a ring carrying a Load hanger. The tensile suspenders or spring balances show the tensile force reading in each of the suspenders which are at about 30 and 45 degrees to the central vertical one. The lengths of each suspender can be adjusted by a threaded rod attached to the spring balance. This can be adjusted via a thumb screw which is located at the end of the adjustable rod. A set of calibrated weights is supplied to apply loading to the hanger which pulls down on the load ring which is connected to each of the spring balances.

Learning Objectives

• To investigate the possibility of redundancy in the vertical tie.
• To compare the sum of the vertical components of the forces in the three wires with the vertical load they support.
• To verify that the horizontal components of the forces in the two oblique rods are equal.