Chapter 11

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