EE WAS DRIVING A CONCRETE TRUCK PAST A PRODUCTION WINDOW WHEN AN AIR MOVER SUPPLY HOSE ATTACHED FROM THE BACK TO A RIB CAUGHT ON THE FRONT OF THE OPERATOR'S CAB. THE HOSE WAS STRETCHED UNTIL T HE AIR MOVER PULLED LOOSE FROM IT'S ATTACHMENT &STRUCK EE ON LEFT SIDE OF HIS HEAD ABOVE THE EAR. WITNESS STATED EE LOST CONCIOUSNESS BRIEFLY.