Sweeper mechanism for heat exchanger

Claim 1

IN A HEAT EXCHANGER HAVING A BURNER MOTOR AND A HOUSING HAVING A SLOT APERTURE IN ITS TOP WALL AND DISPOSED IN A FLUE PIPE AND HAVING A PLURALITY OF PARALLEL HEAT EXCHANGER TUBES DISPOSED IN THE FLUE GASES, A MOVABLE APERTURED SWEEPER PLATE ENGAGING SAID TUBES IN THE APERTURES THEREOF AND DISPOSED TRANSVERSELY TO SAID TUBES, A ROTATABLE RE-ENTRANT SPIRAL SHAFT ENGAGING SAID PLATE AND ELECTRICAL MOTOR MEANS FOR ROTATING SAID SHAFT, THE SAFETY IMPROVEMENT FOR TURNING OFF BURNER MOTOR POWER IN THE EVENT OF MECHANICAL FAILURE COMPRISING TAB MEANS SECURED TO SAID SWEEPER PLATE AND SLIP CLUTCH ELECTRICAL CLOCK MEANS SECURED TO THE OUTSIDE TOP WALL OF SAID HOUSING ADJACENT SAID SLOT APERTURE THEREIN AND DISPOSED OVER SAID TAB MEANS, SAID CLOCK MEANS HAVING AN ELECTRICALLY OPERATED ROTATABLE SHAFT, A FIRST DISC MEANS FIXEDLY SECURED TO SAID SHAFT AND HAVING A RIM TAB DISPOSED IN SAID HOUSING SLOT APERTURE, A SECOND DISC MEANS FREELY MOUNTED ON SAID SHAFT AND HAVING A RIM TAB DISPOSED IN SAID SLOT APERTURE, ARRESTING MEANS DISPOSED ON SAID SECOND DISC FOR ENGAGING SAID FIRST DISC, SPRING MEANS ENGAGING SAID FIRST AND SAID SECOND DISC MEANS URGING CONTINUOUS ENGAGEMENT OF SAID ARRESTING MEANS, A RIM DUAL NOTCHED WHEEL MOUNTED ON SAID SHAFT AND ELECTRICAL CONTACT MEANS ENGAGING SELECTIVELY SAID NOTCHES TO CUT OFF POWER SUPPLY IN THE EVENT OF SWEEPER PLATE FAILTURE OR ELECTRICAL CLOCK FAILTURE.