e., 5" + 21/2" (in the large drawing), as these
circles intersect, as shown at _d_. Arithmetically considered, the
problem is quite difficult, but graphically, simple enough. After we
have swept the circle _A_ with a radius of 5", we draw the radial line
_a f_, said line extending beyond the circle _A_.
LOCATING THE CENTER OF THE BALANCE STAFF.
Somewhere on this line is located the center of the balance staff, and
it is the problem in hand to locate or establish this center. Now, it is
known the circles which define the peripheries of the escape wheel and
the impulse roller intersect at _e e^2_. We can establish on our
circle _A_ where these intersections take place by laying off twelve
degrees, one-half of the impulse arc on each side of the line of centers
_a f_ on this circle and establishing the points _e e^2_. These points
_e e^2_ being located at the intersection of the circles _A_ and _B_,
must be at the respective distances of 5" and 21/2" distance from the
center of the circles _A B_; consequently, if we set our dividers at
21/2" and place one leg at _e_ and sweep the short arc _g^2_, and
repeat this process when one leg of the dividers is set at _e^2_, the
intersection of the short arcs _g_ and _g^2_ will locate the center of
our balance staff.
Pages:
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271