PALMER: THE DESIGNING OF CONE PULLEYS. Ffa 
Fig. 10 shows two views of the assembly drawing of a foot lathe, 
the cones of which were designed just as explained. The fastest 
and slowest speeds were determined, and then the intermediate 
ones found as above. 
With these values for n,, n,, n,, n,, and having determined in- 
dependently what N should be the values of the radii were found 
by the means just explained inthe preceding. It will be seen from 
the cut that it was necessary to proportion the cones in such a way 
that the belt would just miss the bed of the lathe. Several trials 
were made for the first pair of radu, just as under (a), in order to 
get the first pair of steps so that the belt would not conflict with 
the bed of the machine. Then the others came from the diagram 
readily, and the belt was found to just mill the bed when on any 
of the pairs of steps, the large driving wheel having been kept as 
small as possible. 
CASE II—Cones Alike. 
SPEEDS IN CEOMETRIC SERIES. 
When the cones are to be alike, 
R,=r, 
ee 
ie =) 
es (SECa Tae Ere) 
and S ots Sige 
in dN ay Peers ate 
ry i 4 ny, 
Gaeta aban Nl 
ee NG Rane mee 
eyo at Big N 
eNO ne 
Be Ma N 
ie NES Rae is 
From which Oe ——N 3 
eit 
N is then the mean proportional between n, and n,, the extreme 
4? 
speeds required for the driven pulley. If the pulleys are to have 
an odd number of steps the n at the middle pair would equal N. 
So now if the slowest and fastest speeds of the driven cone are 
