Typographic Practice

Page 431

The escapements

414

while the lower one rises so as to hold the second matrix, which assumes the position previously occupied by the one released.

Thus it is that the alternate rising and falling two escapement pawls permits the matrices

of the

one at a time. It is evident that the escapements could be operated directly by rods connected with the finger-keys, but this direct conto escape

nection

is objectionable because of the labor required on the part of the operator, and the danger that the keys may not be fully depressed. Moreover,

essential that the escapements should act individually with moderate speed to the end that the

it is

matrices may be properly engaged and disengaged by the pawls. For these reasons, and to secure easy and uniform action of the parts, the mechanism shown in Figures 9 and 10 is introduced between the finger-keys and escapements. The vertical rods (7,

which actuate the escapements, are guided in main frame and each urged downward by a

the

spring

c.

Each rod C terminates

directly over one

end of a rising and falling yoke-bar a pivot

c3

at the opposite end. c2 is slotted vertically to admit

c2 ,

turning on

Each of the yokes an eccentric c4 turn-

ing on a pivot therein. A constantly rotating rubber-covered roll c 5 is extended across the entire key-

board beneath the cams, which stand normally as shown in Figure 9, 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 c6 and a ,


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