140
=
CN2
Therefore CE = 15·2962 inches, and subtracting this from PE, which is 16 inches (12 + 4 = 16), we get 16 − 15·2962 = 0·7038 as the distance CP, which is the distance moved by the connecting pin for the 30 degrees movement of the crank.
The complete formula is as follows:—
PE − [√(ED2 − DN2) + √(DC2 − DN2)] = CP, or distance moved by the connecting pin for the given number of degrees through which the crank moves, ND being obtained from a table of sines.
To find the distance moved by the connecting pin while the crank moves through 5 degrees—say, from 30 degrees to 25 degrees in beating up.
To solve this it will only be necessary to subtract the length of CE when the crank is forming an angle of 30 degrees from the length of CE when the crank forms an angle of 25 degrees. In the previous example we found that for 30 degrees, CE = 15·2962 inches, and therefore proceeding in the same manner for 25 degrees, we get from table of sines, sin 25° = 0·4226, and 0·4226 of 4 inches 1·69; therefore ND =1·69 inches, and
42 − 1·692
=