MACHINK DRAWING ANH ! 



I OMH - (-iron Pulln/ inth Curved Arm* <n,</ 



Key*. - Draw a complete side elevation and a < 

 of the pulley represented in tin. fc-' to a scale of 8 inches to a foot 

 In drawing the side el i the arms first draw tin- centrelines 



as shown; next draw three circles for each arm, one at each end 

 and one in the middle; the centres of these circles !><:,: M the 

 centre lin ot the arm. and their diameters equal to the widths <>f the 

 arm at the ends and at the middle respect i\ < 1 \. Arcs < >f Hides are 

 then drawn to touch these three circles. The centres and radii <>!' 



Pi':. 42. 



these arcs may be found by trial. The cone 1 < < -uring the 



to the shaft were described on p. L' I 



n 



for Ropes. Ropes made of hemp are now r 

 used t>>r transmit tii These ropes vary 



diameter from 1 inch to 2 inches, and are run at a speed of 

 iboot 4,000 leet per minute. Tin- j>u these ropes are 



made of cast iron, and have their rims grooved as shown in 

 fig. 43, which is a cross section of the rim of a pulley carry- 

 ing three ropes. The angle of the V is usually 45, and the rope 



