We will now take up a study of the detached lever escapement as relates to pallet action, with the point specially in view of constructing an escapement which cannot "set" in the pocket, or, in other words, an escapement which will start after winding (if run down) without shaking or any force other than that supplied by the train as impelled by the mainspring. In the drawing at Fig. 90 we propose to utilize eleven degrees of escape-wheel action, against ten and a half, as laid down by Grossmann. Of this eleven degrees we propose to divide the impulse arc of the escape wheel in six and five degrees, six to be derived from the impulse face of the club tooth and five from the impulse plane of the pallet.
The pallet action we divide into five and four, with one degree of lock. Five degrees of pallet action is derived from the impulse face of the tooth and four from the impulse face of the pallet. The reader will please bear in mind that we do not give these proportions as imperative, because we propose to give the fullest evidence into the reader's hands and enable him to judge for himself, as we do not believe in laying down imperious laws that the reader must accept on our assertion as being correct. Our idea is rather to furnish the proper facts and put him in a situation to know for himself.
The reader is urged to make the drawings for himself on a large scale, say, an escape wheel 10" pitch diameter. Such drawings will enable him to realize small errors which have been tolerated too much in drawings of this kind. The drawings, as they appear in the cut, are one-fourth the size recommended, and many of the lines fail to show points we desire to call attention to. As for instance, the pallet center at _B_ is tangential to the pitch circle _a_ from the point of tooth contact at _f_. To establish this point we draw the radial lines _A c_ and _A d_ from the escape-wheel center _A_, as shown, by laying off thirty degrees on each side of the intersection of the vertical line _i_ (passing through the centers _A B_) with the arc _a_, and then laying off two and a half degrees on _a_ and establishing the point _f_, and through _f_ from the center _A_ draw the radial line _A f'_. Through the point _f_ we draw the tangent line _b' b b''_, and at the intersection of the line _b_ with _i_ we establish the center of our pallet staff at _B_. At two and a half degrees from the point _c_ we lay off two and a half degrees to the right of said point and establish the point _n_, and draw the radial line _A n n'_, which establishes the extent of the arc of angular motion of the escape wheel utilized by the pallet arm.