The crosshead converts the rotating motion of the connecting rod to a linear, reciprocating motion, which drives the piston as shown in Figure 11-10. The crosshead is provided with top and bottom guide shoes, which ride on lubricated bearing surfaces atached to he compressor frame. In addition, balance weights may be attached to the crosshead to reduce unbalanced forces and moments. The connecting rod connects the crankshaft to the crosshead. The piston rod connects the crosshead to the piston.
The crankshaft rotates about the frame axis, driving the connecting rod, crosshead, piston rod, and piston.