SD-1.52-Efficiency of Screw Threads

Three screw thread forms are supplied (‘Vee’ x 2 and square) each with an integral turntable mounted on the top side. Wrapped around the periphery of the turntable is a cord which allows the turntable to be rotated when loaded. Each thread has a mating nut with a profiled groove in its side. This groove locates onto a pin within the wall bracket assembly and stops the nut from rotating when the turntable and screw thread are rotated.
Each nut and thread pairing are quickly and easily interchanged.
The cord is run over the pulley and terminates to a load hanger. This hanger is described as the ‘EFFORT’ hanger. Another hanger is attached to the underside of the shaft of the screw thread and is described as the ‘LOAD’ hanger.
Students vary the LOAD using the calibrated weights and obtain the respective EFFORT required to raise or lower the screw thread. From this the efficiencies can be obtained.