A design for a hammer crusher (fig. 2.9) essentially allows a decrease of the elevated pressure of air in the crusher discharging unit . the a-zone beneath the screen is communicated through the hollow ribs and openings in the body side walls with the b-zone around.Breakout systems. center rock offers a specially designed breakout system for quick bit changes and easy hammer maintenance or repair, on or off site. the hydro-jaw breakout machines use a heavy-duty chainlink jaw design to quickly breakout or make-up bits, dth hammer joints, and other api tool connections to keep your operation running.