THE EMPLOYEE WAS HELPING TO INSTALL A DRIVE SHAFT ON A ROTARY DISCHARGE MACHINE. THE EMPLOYEE WAS LEANING OVER THE EDGE OF THE GEAR HOUSING TIGHTENING THE BOLTS ON THE DRIVE SHAFT. THE EMPLOYEE WAS RESTING HIS CHEST ON THE GEAR HOUSING. THE EMPLOYEE STATES THAT THIS CAUSED HIM TO HAVE A CHEST HERNIA IN THE INCISION AREA WHERE HE PREVIOUSLY HAD HEART SURGERY.