In their arrangement the two pieces represent, as
to distance and curvature, the counterpart of Fig. 168. At the moment of
impact their extreme ends recoil or spring back from the shock of the
escape teeth, but the resiliency of the metal is calculated to be strong
enough to return them immediately to the contact studs _e e_.
As a termination to this chapter, we shall mention the use made at the
present day of the recoil lever escapement in repeating watches. We give
a diagram of this construction in Fig. 170. The lever here is intended
to restrain and regulate the motion of the small striking work. It is
pivoted at _V_ and is capable of a very rapid oscillatory motion, the
arc of which may, however, be fixed by the stud or stop _D_, which
limits the swing of the fly _C_. This fly is of one piece with the lever
and, together with the stud _D_, determines the angular motion of the
lever. If the angle be large that means the path of the fly be long,
then the striking train will move slowly; but if the teeth of the escape
wheel _R_ can just pass by without causing the lever to describe a
supplementary or extended arc, the striking work will run off rapidly.
Pages:
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319