Chapter XII: Plotting Mechanical Motions

To find how much motion an eccentric will give to its rod 223

To find how much a given amount of motion of a long arm will move the
short arm of a lever 224

Example of the end of a lever acting directly on a shoe; a short arm
having a roller acting upon a larger roller 225

A link introduced in the place of the roller to find the amount of motion
of the rod; a lever actuating a plunger in a vertical line, to find
how much a given amount of motion of the long arm will actuate the
plunger 226

Two levers upon their axles or shafts, the arms connected by a link and
one arm connected to a rod 227

A lever arm and cam in one piece on a shaft, a shoe sliding on the line,
and held against the cam face by the rod, to find the position of the
face of the shoe against the cam 228

To find the amount of motion imparted in a straight line to a rod,
attached to an eccentric strap 229

Examples in drawing the cut off cams employed instead of eccentrics on
river steamboats in the Western and Southern States. Different views
of a pair of cams 232

The object of using a cam instead of an eccentric 234

Method of drawing or marking out a full stroke cam 237

Illustration of the lines embracing cut off cams of varying limits of
cut-off 240

Part played by the stroke of the engine in determining the conformation
of cut-off cams; manner of finding essential points of drawings of
cutoff cams 241

A cam designed to cut off the steam at five-eighths of the piston
stroke 244

Three-fourths and seven-eighths cams 246

Necessary imperfections in the operations of cut-off cams 247

Drawing representing the motion which a crank imparts to a connecting
rod 249

Plotting out the motion of a shaper link quick return 250

Plotting out the Whitworth quick return motion employed in machines 253

Finding the curves for moulding cutters 257

CHAPTER XIII.

EXAMPLES IN LINE-SHADING AND DRAWING FOR LINE-SHADED ENGRAVINGS.

Arrangement of idle pulleys to guide bolts from one pulley to another;
representation of a cutting tool for a planing machine 264

Drawings for photo-engraving 267

Drawing for an engraver in wood; drawings for engravings by the wax
process 268

Engraving made by the wax process from a print from a wood engraving;
engravings of a boiler drilling machine 269