TECHNICAL HANDBOOK

INDEX Introduction to truly endless belts Product range Technical calculation Calculation example Belt selection tables Belt installation Positioning and transmission precision Antistatic polyurethane timing belts Measuring lengths MEGAFLEX feasibility table Special execution photos Special execution feasibility Cover properties MEGAFLEX megadynegroup.com

INTRODUCTION TO TRULY ENDLESS BELT Megadyne commenced manufacturing transmission belts in 1957 and extruding polyurethane endless belts in 1990. MEGAFLEX belts are manufactured in thermoplastic polyurethane, which gives superior wear and abrasion resistance. Various grades of steel cords offer good running characteristics even with high tractive load. Great production flexibility grant to designers the possibility to match any technical requirement and solution. By selecting different components and materials, MEGAFLEX belts can be manufactured to meet every customer requirement. Megadyne has...

PRODUCT RANGE Thanks to their features, MEGAFLEX belts can be successfully used in a wide range of application such as: • • • • • • • • DOUBLE SIDED High Power Transmissions Ceramic industry Marble & Stone industry Glass Industry Painting Mixer machines Heavy Transport systems Wood industry Food industry

CLASSIFICATIONS CLASSIFICATIONS MEGAFLEX timing belts are manufactured in thermoplastic polyurethane, with single helicoidal steel cords. This type of belts, developed by our Research & Development, offer good running characteristics and high-traction loads. They are especially suited for power transmissions and conveying with high loads and speeds. The addition of a nylon coating on the teeth during production enhances the running properties for specific applications and reduces the noise thanks to a lower frictional coefficient. On the back of the belt an extra thickness of special coating...

CLASSIFICATIONS MECHANICAL AND CHEMICAL CHARACTERISTICS BODY MEGAFLEX belts are manufactured with white thermoplastic Polyurethane 92 ShA as standard. Special compounds (different hardness, special properties) are available on request. Special compound and cords have to be tested and homologated on the application. Megadyne is not responsible for the wrong functioning of special product. Here under some PU characteristics: WATER No problem in normal or sea clean water, at room temperature. Over 60 ºC there is a fast decrement of breaking strength. ACIDS In acid diluted proportions, at room temperature,...

CLASSIFICATIONS MECHANICAL AND CHEMICAL CHARACTERISTICS CORDS STANDARD CORD MEGAFLEX is manufactured with helicoidal zinked steel cords as standard. KEVLAR ® Kevlar ® tension cords are suggested in: • Non-magnetic, for use in drives with metal detectors • Food industry • Applications in damp environments must be avoided Kevlar ® cord belts have a lower dimensional stability compared to steel-cord belts. Length and tolerance may change. HP High Performance cords have 25% more strength capacity than standard cords. They are recommended for high-repeatability applications. HF High Flexibility cords...

CLASSIFICATIONS COATING MEGAFLEX can be manufactured with special coating on the teeth or on the back. Please check on pages 50 and 51. Other covers on request. IDENTIFICATION CODE Using the information in the table below, it is possible to identify the correct belt for every application. The code is composed of letters and numbers like in the following example: 1 MFX SPECIAL MANUFACTURES This number indicates the requested belt width. The value is in mm for a belt with pitch in mm, and in inches for a belt with pitch in inches. This code is composed by letters and indicates the profile. This...

TECHNICAL CALCULATION SYMBOL UNIT SYMBOL UNIT belt width belt length peripheral force centre distance transmittable force per tooth per unit pitch diameter of pulley i drive torque total conveyed mass drive power belt speed force exerted by mass (m) safety factor number of teeth on the pulley i number of teeth in mesh on the drive pulley coefficient of friction between belt and guide number of teeth on the small pulley belt pitch number of teeth on the largest pulley Breaking Strength Max traction load is the maximum acceptable traction on cords. Breaking-strength is the necessary load to break...

TECHNICAL CALCULATION CALCULATION OF THE PERIPHERAL FORCE ON THE TIMING BELT For horizontal & conveying drives Knowing mass (Note: values of μ can be found in table 3 on page 12) Knowing drive torque Knowing drive power DETERMINATION OF THE BELT WIDTH The belt width b should be calculated using the following formula Cs safety factor from page 13 table number 4 from above calculation number of teeth in mesh on driver pulley (nearest lower integer number) (if calculated Zm > 12 for an open-end application use Zm = 12) transmittable force per tooth per unit width (see table on belt data pages) PRE-TENSIONING...

CALCULATION EXAMPLE CHOICE OF BELT PITCH, LENGTH AND PULLEY According to the belt pitch selection, table n.1 on page 11, considering the value of P and RPM, we select RPP5. Then we consider the nearest pulley diameter to the requested value and the corresponding n. of teeth (see technical information on page 29). Therefore z 1 = 30 teeth (d 1 = 47,75 mm) and z 2 = z 1 • 2 = 60 (d 2 = 95,49 mm). Belt length is L = 2c+1,57 (d 1 + d 2) + [(d 2 - d 1)² / 4c] = 2 • 900 + 1,57 • (47,75 + 95,49) + (95,49-47,75)² / (4 • 900) = 2025,5 mm. Because of this, the actual center distance will be: CALCULATION...

BELT SELECTION TABLES BELT PITCH SELECTION TABLE 1 100 BELT WIDTH SELECTION TABLE 2 100

BELT SELECTION TABLES TABLE 3 - FRICTION COEFFICIENT BETWEEN BELT AND GUIDE Volvent friction on dry surface Polyurethane / smooth steel Polyurethane / rough steel Polyurethane / abrasive steel Polyurethane NFT / smooth steel Polyurethane NFT / rough steel Polyurethane NFT / abrasive steel Polyurethane / nylon Polyurethane / aluminium Roller / polyurethane belt The choice of the SAFETY FACTOR C s, depends on the operating condition. The following table shows the value to be used: TABLE 4 - SAFETY FACTOR Driven Machine Computers, printers Teleprinters, photocopiers Motion-picture projectors and...