Fig. 129.
(221.)
Fig. 130.
Fig. 131.
By this arrangement the force by which the piston is driven in its ascent and descent is communicated to the connecting rod, not, as usual, through the intervention of a piston-rod, but directly from the piston itself by the cross-pin I, and from thence to the crank C, which it drives without the intervention of beams, cross-heads, or any similar appendage.
The slide-valves regulating the admission and eduction of steam are represented at a; the rod of the air-pump is shown at d, being worked by a crank placed on the centre of the great crank shaft.[38]