Needing a Flat Belt style Pulley transmission system for my turbine I found this book titled – A treatise on belts and pulleys By John Howard Cromwell published 1885.
I was just wanting a general outline of the style and dimensions for a pulley and this book pretty much will answer any question I have. Like many book from the period it is very wordy – I think they were probably paid by how many words were in the book. This blog gives me a chance to winnow out the bits that I need.
Geeze. Trying to make sense of this is fun – in a .. hitting your finger with a hammer feels better when you stop – kinda way.
The rim of a pulley intended to carry a flat belt is generally rounded (Figs. 48 and 49), in order that the belt may remain in the centre of the pulley-fact, instead of working to one side, as is the case with flat-faced pulleys. The amount of this rounding (s) may be taken equal to the width of the belt.
B = Face Width
The thickness k of the edge of the rim, or the thickness at the ends of the face-width, may be easily calculated from the formula –
k = Rim Thickness
The thickness of the rim at the center is therefore the rounding + thickness at the rim.