mechanism shown in Figs. 5 and 6 is introduced between the finger-keys
and escapements. The vertical rods _C_, which actuate the escapements,
are guided in the main frame, and each is urged downward by a spring
_c_. Each rod _C_ terminates directly over one end of a rising and
falling yoke-bar _c2_, turning on a pivot _c3_ at the opposite
end. Each of the yokes _c2_ is slotted vertically to admit an
eccentric _c4_ turning on a pivot therein. A constantly rotating
rubber-covered roll _c5_ is extended across the entire keyboard
beneath the cams, which stand normally as shown in Fig. 5, out of
contact with the roll. When the parts are in this position, the cam-yoke
is sustained at its free end by the yoke-trigger _c8_, and a
cross-bar in the cam engages a vertical pin _c7_ on the frame,
whereby the cam is prevented from falling on to the roller, as it has a
tendency to do. Each of the yoke-triggers _c6_ is connected with a
vertical bar _c8_, which is in turn connected to the rear end of a
finger-key lever _D_. The parts stand normally at rest in the position
shown in Fig. 5, the roll _c5_ turning freely under the cam without
effect upon it.

When the finger-key is depressed, it raises the bar _c8_, which in
turn trips the yoke-trigger _c6_ from under the cam-yoke _c2_,
permitting the latter to fall, thereby lowering the cam _c4_ into
peripheral engagement with the rubber roll, at the same time disengaging
the cam from the stop-pin _c7_. The roll, engaging frictionally with
the cam, causes the latter to turn on its centre in the direction
indicated by the arrow in Fig. 6.

Owing to the eccentric shape of the cam, its rotation while resting on
the roller causes it to lift the yoke _c2_ above its original
position, so that it acts upon the escapement rod _C_, lifting it and