Welded Conveyor Pulleys (English Edition) [Kindle-editie] beoordelingen het boek quotes

One of the tasks assigned to engineers is the design of structures which can be produced at the lowest possible cost and will satisfactorily meet all requirements as regards operating conditions. Consequently, the designer should fully investigate the problems he is to treat from a theoretical point of view using all the knowledge offered by engineering science, and in this manner aim at eliminating as many uncertainties as possible.In every branch of engineering there is sufficient scope for such investigations, and this thesis endeavors to make a contribution toward clarifying the principles of the design of one of the items which make up a belt conveyor. Installations of this type play an important part in the mechanical handling of a wide variety of materials, and one of the elements used are pulleys which serve to drive and support the belt.Apart from those very rare cases where unusual conditions may demand the use of certain special materials, pulleys made of cast iron or mild steel are ‘commonly’ employed. The latter type in the form of welded steel pulleys has some distinct advantages over cast iron pulleys such as:small weight,lower cost of material,greater reliability,no patterns necessary.To these points in favor may be added the lower cost of machining particularly when pulley shaft, discs and shell are welded together to form one unit. However, since the manufacture of welded steel pulleys inevitably involves far more labor for marking, cutting, rolling, assembling and welding, the advantage gained by the reduction of machining costs is partly or wholly lost owing to the expense incurred in the boilermaker’s shop.The purpose of this thesis is to analyze the stresses produced in the shell of steel pulleys and to derive formulae for calculating these stresses which will assist designers in determining an economical thickness of the shell.