Installation Tensioning Procedure

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3 Contents PARTICULARS Introduction PIX X treme HTD Belts Construction Features Designation Pitch range Length range Pulley Dimensions Length tolerances Width tolerances PIX X treme Classical Belts Construction Features Designation Pitch range Length range Pulley Dimensions Length tolerances Width tolerances Belt Drive Selection Procedure Drive design example Centre Distance tables Power Rating Tables Drive alignment Installation and Tensioning Allowance Idlers Installation Tensioning Procedure Tolerance on Pulley Dimensions Trouble shooting Storage of Synchronous Belts PAGE NO

SYNCHRONOUS BELTS INTRODUCTION Timing belt can best be described as that belt with integrally moulded teeth on its inside which makes positive engagement with axially grooved pulley.

Its unique feature enables it to use in positive drive resulting in precise movement of drive components.

4 SYNCHRONOUS BELTS INTRODUCTION Timing belt can best be described as that belt with integrally moulded teeth on its inside which makes positive engagement with axially grooved pulley. Timing belt is also known as synchronous belt or positive drive belt. Timing belt drive is not considered as a substitute or replacement to other modes of belt drives. Its unique feature enables it to use in positive drive resulting in precise movement of drive components. Synchronous belts are offered in two different teeth profile; one is classical timing belt and another is High Torque Drive (HTD) belts. The classical timing belt has trapezoidal teeth profile and HTD has curvilinear or spherical teeth profile. Due to difference in teeth profile as well as in their torque transmitting capability, these belts can not be interchanged. HTD timing belts are used in application where in high torque is to be transmitted from one shaft to another and classical timing belts for precise displacement with relatively light duty application. PIX X treme CLASSICAL SYNCHRONOUS BELTS Nylon Facing Polychloroprene Backing Fibre Glass Cords Polychloroprene Teeth Fig.1 Construction The belt backing and teeth are made up of strong polychloroprene rubber, it protects the cords from oil, grease, moisture etc. and also gives bonding to the cords. Fiber glass cords act as a tensile member and provides high tensile strength, excellent flex life and high resistance to elongation. The teeth are covered with wear resistant specially woven stretchable nylon fabric. Refer (Fig.1) FEATURES Tooth profile PIX X treme classical synchronous belts have trapezoidal teeth profile and they are available in XL, L & H sections. High efficiency by positive drive The teeth on the belt meshes with the grooves on the pulley and thereby transmits power from one to another end by positive engagement. Hence, there is no slippage between belt and the pulley. Free from Maintenance Unlike chain drives, there is no metal-to-metal contact in the synchronous belt drives and hence no need of lubrication. No high tension Since the working principle is not based on friction, there is no high tension required on the belt unlike normal v-belts. Also, the presence of special cord material protects the belt from any elongation during working and hence maintains the tension of the belt to the required value. Compact design PIX X treme classical synchronous belts allow use of small pulleys and shorter distance, these factors with higher power to weight ratio enables to use compact drive centre. Low noise level PIX X treme classical synchronous belt drives offer lower noise levels and are smooth in operation. 1

5 Wide range PIX X treme classical synchronous belts offer a wide range of speed and power transmission capacity. Standard Conforms to BS 45 DESIGNATION PIX X treme classical synchronous belts are designated by the following parameters Pitch Length Pitch Length is specified in 1/th of inch of the total length (circumference) as measured along the pitch line. The theoretical pitch line of a classical synchronous belt lies within the tensile member as shown in fig. 1.1 Tooth Pitch Tooth Pitch is the linear distance between two adjacent teeth along the pitch line as shown in fig. 2. Belt Width Belt Width is the cross-sectional width of the belt. This is specified in terms of 1/th of an inch. Example PIX X treme 650 L Pitch Length L Pitch mm Belt Width C B Pitch w Fig.3 CROSS SECTION DIMENSIONS Section XL L H Pitch (mm) Tooth height B (mm) Belt Thickness C (mm) Table1 Pitch (Circular pitch) Pitch Line Pitch Dia met er Outside Diameter Pulley Pitch Circle Fig.2 2

6 RANGE : Classical Belts PIX X treme XL Classical Belt Sizes PIX X treme L Classical Belt Sizes PIX X treme H Classical Belt Sizes Section Pitch Length No. of teeth Section Pitch Length No. of teeth Section Pitch Length No. of teeth 1 XL 1 XL 0 XL 0 XL 170 XL 0 XL 1 XL 0 XL 2 XL 2 XL 2 XL 0 XL 270 XL 0 XL 3 XL 4 XL 450 XL L 7 L 3 L 0 L 5 L 2 L 255 L 270 L 5 L 0 L 2 L 3 L 5 L 7 L 3 L 4 L 450 L 0 L 5 L 5 L 0 L H 2 H 255 H 270 H 0 H 0 H 0 H 3 H 0 H 370 H 375 H 3 H 0 H 4 H 4 H 450 H 465 H 0 H 4 H 5 H 5 H 5 H 570 H 0 H 6 H 6 H 700 H 5 H 750 H 770 H 0 H 8 H 8 H 850 H 0 H 0 H 1 H Note : More and More sizes are being added to both HTD & Classical Belts. Please check in for new additions at or contact us at info@pixtrans.com 3

7 PIX X treme HTD BELTS Polychloroprene Backing Construction The belt backing and teeth are made up of strong polychloroprene rubber. It protects the cords from oil, grease, moisture and also gives the bonding to the cords. Fibre Glass Cords Polychloroprene Teeth Nylon Facing High strength fibre glass cords provide resistance to belt elongation and stretch. Specially woven stretchable nylon fabric provides an excellent wear resistance. Fig.4 Improved tooth design ensures better stress distribution and reduces tooth jump. FEATURES High efficiency by positive drive The special construction of the synchronous belt gives the positive grip of teeth with the pulley grooves and hence there is no slippage and speed variation. Unlike V-belt drives there is no wedging action and the drive operates by the positive engagement between the belt teeth and pulley grooves. Free from Maintenance Unlike chain / gear drives there is no metal to metal contact in the Synchronous belt drive and hence no need for periodic lubrication. Also due to the presence of special cord material re-tensioning is not required. No High Tension Unlike V-belt drive, in Synchronous Belt there is no wedging action between belt and pulley hence Synchronous belt doesnot require high tension, less tension means less load on the shaft and bearings - longer life. Compact Design Synchronous belts being thinner and extremely flexible, hence it can operate efficiently even with smaller diameter timing pulleys. Low Noise Level As compared to chain or gear drives Synchronous belt drives offer lower noise levels and are smooth in operation. Higher Power HTD belts have higher power transmission capacity than Classical timing belts because of better stress distribution. Wide Range PIX X treme belts offers a wide range of speed and power transmission capacity. Designation PIX X treme HTD belts are designated by the following parameters Pitch Length Belt pitch length is the total circumferential length in mm measured along the pitch line. Tooth Pitch Belt tooth pitch is the linear distance in mm measured between the two adjacent teeth along the pitch line. Belt Width Belt width is the distance in mm as measured across the length of the belt between two sides edge of the belt. 4

Example : PIX X treme 0 8M 0-0 mm Pitch Length 8M - 8 mm tooth pitch - mm belt width PIX X treme HTD Belts are supplied in three different pitches Section 5M 8M M Pitch (mm) 5.

8 Example : PIX X treme 0 8M 0-0 mm Pitch Length 8M - 8 mm tooth pitch - mm belt width PIX X treme HTD Belts are supplied in three different pitches Section 5M 8M M Pitch (mm) Tooth Height B (mm) Belt Thickness C (mm) C B Pitch w Pitch (Circular pitch) Pitch Line Pitch Diameter Outside Diameter Pulley Pitch Circle 5

9 RANGE : HTD BELTS PIX X treme 5M HTD BELT SIZES PIX X treme 8M HTD BELT SIZES PIX X treme M HTD BELT SIZES Section Pitch Length No. of teeth Section Pitch Length No. of teeth Section Pitch Length No. of teeth 350 5M 0 5M 425 5M 450 5M 475 5M 500 5M 525 5M 535 5M 550 5M 5 5M 5 5M 0 5M 6 5M 635 5M 6 5M 665 5M 670 5M 700 5M 7 5M 750 5M 0 5M 835 5M 850 5M 8 5M 870 5M 8 5M 895 5M 0 5M 925 5M 935 5M 950 5M 9 5M 0 5M 50 5M 1 5M 5M 5M 70 5M 5M 00 5M 95 5M 70 5M 00 5M M 0 8M 5 8M 5 8M 5 8M 0 8M 6 8M 7 8M 7 8M 0 8M 8 8M 8 8M 9 8M 9 8M 968 8M 0 8M 8M 8M 11 8M 8M 8M 8M 8M 8M 8M 8M 8M 00 8M 17 8M 00 8M 14 8M 00 8M 8M 8M 8M 8M 00 8M 00 8M 00 8M 8M M 11 M 11 M M M M 1750 M 1778 M M 19 M 00 M M 23 M 50 M 25 M 00 M 30 M Note : More and More sizes are being added to both HTD & Classical Belts. Please check in for new additions at or contact us at info@pixtrans.com 6

10 BELT DRIVE SELECTION PROCEDURE Design Inputs : Following are the input data required to design the Synchronous belt drive Power to be transmitted Speed of the driver pulley Speed of the driven pulley Distance between centres of pulleys Operational hours per day The steps required to design the drives are as below - Step I SERVICE FACTOR For a better performance of Synchronous belt drive it is very important to choose appropriate service factor while designing the drive. Service factor depends on the type of application, working conditions and working hours. The basic service factor Ka can be found out using Table no. (B), on page no. 8 However if exact application cannot be matched in the table, find the service factor considering the similar functional machine in a column whose load characteristics are similar to the machine which is being used. If an idler is used in the drive, an additional value Ki, 0.2 is to be added in the service factor Ka. However, if the drive is speed increasing an additional value ksu to be added to the service factor Ka by referring the table no. (A), on page no. 7. Unusual shock loads, critical drive conditions and surrounding conditions demand the special attention to the drive and in such cases our Technical Services Department should be consulted for a proper drive solution. Please send your queries at info@pixtrans.com Table A : Speed up Ratio (Ksu) Speed up Ratio & above Additional value Step II CALCULATE DESIGN POWER Design Power = Required power x Service Factor Pd = Pr x (Ka + Ki + Ksu) Multiply the power required to be transmitted by the service factor considering all the three conditions, viz. Idler, speed up ratio and basic service factor 7

11 Table B : SERVICE FACTOR TABLE (Ka) Driving Unit AC motors : Normal torque, squirrel cage, synchronous and split phase DC motors : Shut wound, multiple cylinders internal Combustion engines. AC motors : High torque, high slip, repulsion-induction, single phase series wound and slip ring DC motors : Series compound & compound wound, single cylinder internal combustion engines, line shafts, clutches Driven Machine Intermittent service (3-8 hrs daily or seasonal) Normal Service (8- hours daily) Continuous Service (- hours daily) Intermittent service (3-8 hrs daily or seasonal) Normal Service (8- hours daily) Continuous Service (- hours daily) Sewing machines, display equipment, medical equipment, office machines, measuring devices Screens, conveyor belts, for light packaging, band saw, drums Agitators and mixers, paper machineries, drill press, lathes, circular saw, planers, printing machines, laundry machines Conveyor belts for heavy products (coal, sand etc.) Grinders, shapers, machine tools, line shafts, milling machines, centrifugal pumps, textile machineries (reels), centrifugal compressors Brick machineries, heavy conveyor belts, bucket elevators, fans and blowers, centrifugal & induced draft exhaust, generators, rubber calendars, mills, extruders, saw mill machineries, looms, spinning Hammer mills, conveyor : flight, screw paper pulp Brick and clay mills, fans blowers, propellers mine fans, +ve blowers Reciprocating compressors, ball mills, reciprocating pumps Step III LOCATE THE BELT SECTION To select the Belt section, refer belt section selection graph on page 9. Belt section can be selected by locating the point of cross section of RPM of smaller pulley and the calculated design power. If the point of intersection lie in the vicinity of the line between two adjacent pitches, then the section can be selected by considering the size and economical factors. 8

12 00 PIX X treme HTD BELT SECTION SELECTION CHART RPM of Faster Shaft 0 5M 8M M Design Power (Kws) 00 PIX X treme CLASSICAL BELT SECTION SELECTION CHART RPM of Faster Shaft 0 XL L H Design Power (Kws) 9

13 Step IV SELECTION OF DRIVER AND DRIVEN PULLEY AND BELT LENGTH Find out the speed ratio by dividing the RPM of the smaller pulley by the RPM of the larger pulley.to select the pulley combination and belt pitch length, first locate the calculated speed ratio in the first column of the centre distance tables given on pages from If there are more than one rows for a single value of speed ratio than the row can be selected by considering the centre distance and pulley combination required. Once the speed ratio is located, by moving along the same row centre distance nearest to the requirement can be selected and corresponding belt pitch length and no. of teeth are available on the top of the column with the required centre distance Step V POWER RATING To find the power rating of the selected belt section, refer the tables on page no The power rating of the belt section in consideration can be located by the point of intersection of the row headed by RPM of the smaller pulley and the column headed by the number of grooves on the smaller pulley,. The power rating tables for a particular section are given for different belt widths. If the power rating of the selected belt with a particular width is less than the calculated design power, then the belt with higher width may be considered to get the required power rating. The power ratings provided in the tables are based on minimum six teeth of belt in mesh. If the number of teeth in mesh is less then six than the power rating should be multiplied with the teeth in mesh factor as given in the following table. Teeth in mesh 6 or more Factor

14 DRIVE DESIGN EXAMPLE Drive Inputs : Power to be transmitted - 13 kws Driven Speed - 00 RPM Working hours - hrs/day Driver Speed - 0 RPM Centre - Centre distance - 0 mm Type of application : Printing Machines Step I : SERVICE FACTOR Selecting an appropriate service factor depending upon the application and working hours. From Table B, (page no. 8) for AC motor with printing m/c and hours a day working hours, the service factor is selected as, Ka = 1.4 As the drive is speed increasing with the speed ratio of added to the service factor. (Page 7) 00 0 = 2 an extra value Ksu = 0.2 is to be Step II : DESIGN POWER Design Power = Required Power X Service Factor = P r X (Ka + Ksu) = 13 X 1.6 =.8 kws Step III : LOCATE THE BELT SECTION Refer to page no. 9 to locate the belt section. Consider the speed of the smaller pulley i.e. 00 RPM and the design power to select the suitable belt section. For the design power of.8 kws and 00 RPM the belt section selected is 8M Hence the required belt section is 8M. Step IV : SELECTION OF DRIVER & DRIVEN PULLEYS AND BELT LENGTH With the help of speed ratio of the drive and the centre distance the combination of pulleys and belt length can be calculated. Refering to the page no. 85, the pulley combination and belt pitch length corresponding to the speed ratio 2 and centre distance of 0 mm, are as follows; Driver pulley Groove = grooves Driven pulley Groove = grooves Belt Pitch Length = 9 mm Lp Step V : BELT WIDTH & POWER RATING To decide the belt width, refer page no. 57, giving power rating table of 8M HTD belt with 85 mm belt width. For the combination of small pulley grooves and its speed the power rating of the belt is. kws. Since the design power is.8 kws, which is less than. kws, hence 85 mm belt width is sufficient to transmit the required power. Hence, Belt width = 85 mm 11

15 The power rating tables are based on six teeth in mesh. To calculate the power transmission capacity of a belt, No. Of teeth in mesh is required which is calculated as follows ; teeth in mesh = [ D - d ] Z I 6C Where, D - Pitch dia. of Larger pulley d - Pitch diametre of smaller pulley C - Centre Distance Z - No. Of grooves on smaller pulley I Hence, Teeth in mesh = [ ] x 6 X 0 =.91 teeth As the no. Of teeth in mesh are more than 6, the correction factor is 1 which indicates that the power rating of the belt with 85 mm belt width will remain unchanged. Summary Belt Section - 8M Belt Length - 9 mm Lp Belt width - 85 mm PIX Equivalent - 9 8M 85

16 13 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with 6.35 mm of Belt Width

17 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with 7.94 mm of Belt Width

18 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with 9.35 mm of Belt Width

19 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with.9 mm of Belt Width

20 17 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with.7 mm of Belt Width

21 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with.7 mm of Belt Width

22 19 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with mm of Belt Width

23 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with.1 mm of Belt Width

24 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with 25.4 mm of Belt Width

25 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with 31.8 mm of Belt Width

26 23 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme XL Classical belt with.1 mm of Belt Width

27 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme L Classical belt with 9.53 mm of Belt Width

28 25 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme L Classical belt with.7 mm of Belt Width

29 Speed of smaller pulley RPM No. of grooves on smaller pulley POWER RATINGS - KILOWATTS PIX X treme L Classical belt with.7mm of Belt Width

E2/20099 ED Design Manual. NEW PowerGrip GT3. Industrial Synchronous Belts PowerGrip GT3 PowerGrip HTD PowerGrip

E2/20099 ED Design Manual. NEW PowerGrip GT3. Industrial Synchronous Belts PowerGrip GT3 PowerGrip HTD PowerGrip E2/20099 ED 2005 NEW PowerGrip GT3 Design Manual Industrial Synchronous Belts PowerGrip GT3 PowerGrip HTD PowerGrip DRIVE DESIGN MANUAL FOR POWERGRIP GT3, POWERGRIP HTD & POWERGRIP SYNCHRONOUS BELTS CONTENTS