83 



Let Bi^=belt-pull ilue to total teiii^ions acting at an angle, 3, with the horiz- 

 ontal ; 



B'=belt-piill due to tensions in main belt acting at an angle, a. , with 

 the horizontal ; 



V^ ^linear velocity of main belt from fly-wheel : 



V=average linear velocity of cross belts ; 



VI . . . . 



r^^^ratio ot velocity ot main belt to average velocity of cross belts, 



then the horizontal puU^B^ coscc -1-Bi cos ,■> ( 11 ) 



and the vertical pull=Bi sin x -i-B^ sin ? (12) 



But B' =h= 1000 ^^-^ ' ( 13) 



r Vr 



therefore, the horizontal piill^Bj ( ~" + cos 3\ — .r; 



^ r — 



and the vertical pnll^B'( ^ " -j- sin 3 ) = (/: 



r — / • 



If a =0 and p=0, 



thenr=B, (A - 1 ) 

 r — ^ 



and 1/^=0. 



The most usual case, when the power is not taken ofl' eijually on either side, 



will be that in which main belt makes an angle with the horizontal, and the cross 



belts are themselves horizontal, that is: 



■ x=B, (^^li^-l) 

 r ^ 



B, . 



V =: — - Sin X 



r 



When the horizontal cross-belts are distributed equally on either side of the shaft 



the only load we need consider will be that due to the main belt, in which case 



X = Bj cos X , 



and 



r 



y ^ B , sin X . 



r 



If the machines be driven from below, the pull of tiie belts, instead of adding 

 to the load on the bearings, will cause this load to be decreased; but as this 

 method is not usual we shall not consider it here. 



