Philippine Agricultural Engineering Standard PAES 302:2000 PDF

PHILIPPPINE AGRICULTURAL ENGINEERING STANDARD PAES 302:2000 Engineering Materials – Flat Belts and Pulleys for Agricultural Machines – Specifications and Applications 1 Scope This Standard establishes specifications and provides technical information for the prop...

PHILIPPPINE AGRICULTURAL ENGINEERING STANDARD PAES 302:2000 Engineering Materials – Flat Belts and Pulleys for Agricultural Machines – Specifications and Applications 1 Scope This Standard establishes specifications and provides technical information for the proper application of flat belts and pulleys for drives in agricultural machinery. 2 Reference The following normative references contains provisions which, through reference in this text, constitute provisions of this Standard: PAES 304:2000, Engineering Materials – Keys and Keyways for Agricultural Machines – Specifications and Applications 3 Application Flat belts are commonly used where center distances between pulleys are fairly long. They are very flexible and can transmit power in quarter twist and crossed drives. 4 Definitions 4.1 flat belt belts used to transmit rotary motion and power between two shafts, which lie flat on the face of its corresponding pulley 4.2 flat belt pulley wheel having flat or crowned face used to transmit motion and power by means of flat belts 4.3 flat belt drive power transmission device used to transmit power and motion between two shafts consisting of flat belts which ride in flat pulleys 4.4 pulley diameter outside diameter of the pulley 4.5 belt length stretched-out length of the belt  PAES 302:2000 4.6 speed ratio ratio of the angular velocities of the pulleys making no allowance for slip and creep 4.7 belt speed the linear speed of the belt calculated by multiplying the rpm and the diameter of the driver pulley and to the value of pi 5 Flat belts 5.1 Nomenclature Dimensions of flat belts are designated by its width (W), and by its thickness (t). 5.2 Materials Flat belts for agricultural machinery are usually made of rubberized cord and fabric and reinforced nylon cords. Flat belts may be spliced to obtain the desired loop size or made as a continuous loop. They can be arranged in layers or in plies. 5.3 Rubberized fabric 5.3.1 Description Rubber belting is made from fabric or cord, impregnated and bound together by vulcanized rubber compounds. Advantages are high tensile strength, strength to hold metal fasteners satisfactorily and resistance to deterioration by moisture. Rubber belts are used in places exposed to the weather or the action of steams. 5.3.2 Specifications Table 1 specifies the power rating (in watts per millimeter of belt width) for rubber belts given the number of ply and the types of rubber used while Table 2 specifies the minimum recommended diameters for rubber belts. Minimum and maximum number of ply is specified in Table 3. C-23