Home Page T-10 SECTION 5    DIFFERENT BELT CONFIGURATIONS 5.1  Double Sided Twin Power Belt Drives Timing belts are also available in double sided designs, which offer an infinite number of new design possibilities on computer equipment, business machines, office equipment, textile machines and similar light-duty applications.  Belts with driving teeth on both sides make it possible to change the  direction  of  rotation  of  one  or  more  synchronized  pulleys  with  only  one  belt.    The  inside  and outside teeth are identical as to size and pitch and operate on standard pitch diameter pulleys. If the belts have nylon facing on both sides, then the same design parameters can be used for the  drives  on  both  sides  of  the  belt.    In  case  the  outside  teeth  do  not  have  nylon  facing,  the horsepower rating of the outside teeth is only 45% of the total load. For example:  assuming the drive pulley and   belt   are   capable   of   transmitting   1 horsepower, 0.55 hp can be transmitted from the  inside  teeth  of  the  pulley  (A),  and  0.45 hp can be transmitted by the outside teeth to pulley (B) for a total of 1 hp, the rated capacity of the driver pulley. 5.2  Long Length Timing Belt Stock These  belts  are  an  excellent  solution  for  drives that require belt lengths longer than those produced in conventional  endless  form.    Long  length  belting  has the  same  basic  construction  as  conventional  timing belts.    These  belts  are  usually  produced  by  spiral  cut of large diameter endless belts. These belts are creatively used in: •  reciprocating carriage drives •  rack and pinion drives •  large plotters An example of application is shown in Figure 13. A complete timing belt and a timing belt segment reduce vibration and chatter in this oscillating drive for a surface grinder. SECTION 6    BELT CONSTRUCTION The load-carrying elements of the belts are the tension members built into the belts (see Figure 14). These  tension  members  can  be made of: 1.    Spirally wound steel wire. 2.    Wound glass fibers. 3.    Polyester cords. 4.    Kevlar. Fig. 11    Double Sided Timing Belt Pulley B Outside Teeth .45 hp Pulley A Inside Teeth .55 hp Driver Output 1 hp 3–––––––––––––  Belt Direction Fig. 13    Example of Timing Belt Stock Use Fig. 14    Belt Construction Curvilinear Fig. 12    Timing Belt Stock