414
Molesworth’s pocket-book
Pulleys.
Convexity of pulleys to receive the stiap =
I to in. per foot of width in high speeds = | in
low speeds.
V = Velocity of driving pulley.
v = Velocity of driven ditto. .
D = Diameter of driving pulley.
d = Diameter of driven ditto.
VD
v~ d ’ .
In a train of pulleys the final velocity =
V X D X Dj<ü,j£' where D' D" are the dia-
d x dl x &c.
meters of the driving pulleys, and d a those oi
the driven.
Leather Belting.
W = Velocity of belt in feet per minute.
HP = Horse-power (actual) transmitted by belt.
S = Strain on belting in lbs.
X = Width of single belting (T3W thick) in inches.
8 = ,+ ^ W = -02S.
33000 HP
x ~ v •
■k - 1 • 1 when portion of driven pulley embraced
by belt = ‘ 40 circumference.
k = 'll when portion of driven pulley embraced
by bolt = '50 circumference.
k = -62 when portion of driven pulley embraced
by belt — ’60 circumference.
For double belting the width = W X 0’6.
Approximate rule for single belting, thick.
w 1100 HP
w = ~v“ •