The oil pressure in the main cylinder is transferred to the small dynamometer cylinder. The dynamometer piston is kept rotating at a slow speed to ensure dynamic friction condition. The piston exerts a force proportionate to the pressure on the hanger connected to one arm of the pendulum, through an auto range selecting lever system. This force deflects the pendulum. The range selection can be effected by simply turning a knob, provided outside of the panel. An effective damping arrangement is provided to ensure slow return of the pendulum after sudden fracture of the test specimen.
The pendulum lever pushes the rack which slides over two pulleys. The rack movement is proportionate to the load. A pinion in engagement with the rack rotates and moves the pointer fixed to its shaft. The pointer moves over a large dial indicating the load. A window-type dial is provided for easy and clear change of the load range.
A continuous roll type load elongation recorder is provided for plotting a load-elongation graph. Load is plotted by the horizontal movement of the rack. Elongation is plotted on the vertical axis and is equal to the movement of the main piston. Elongation ratio of 1:2 & 1:5 can be obtained.
All measuring ranges of the machine are calibrated within an accuracy of ±1% from 20% to 100% of each range as per IS: 1828 and BS: 1610.