54 



MVHINK r>n.\ \\T\-; \\n r>: 



as tli ! tin- >t)ier ends at tin- same time as tin- 



pin. This cm determines tin- oeotret for the ATOI 



shown in the en<l % 



-Draw to a scale of 2 inrhcs t n f.- 

 ana 11. 1 rli '\ations of the loconiotr 

 fig. 48. The distance between the cent re lines >f the cvlin : 



/;,iiff.nft Crunks. Tin- form of cranked shaft shown in 

 fig. 48 is largely used for marine engines, but for the \. -i \ ; 



42-'-- 



I'lO. 4. 



ful engines now fitted in larire sliij.s tlii^ desi<rn of shaft is 



v unrolial)le, tho luilt-up crank shown in fig. 1 

 preferred, although it is much heavier than the other. It will 

 1* seen from the figure that the shaft, crank arms, and crank- 

 l>in an made separately. The arms are shrunk on to tho pin 

 and the shaft, and secured to tin- latt.-r 1-y sunk keys. Tl 

 heavy shafts and cranks are generally made of steel. 



EXERCISE 50. Keeping to the dimensions muiktd in i 

 draw the views there shown of a bnilt-nj> crank-shaft for a marine 

 engine. Scale | inch to a foot. 



