Machine for sandblasting

Claim 1

A MACHINE FOR SANDBLASTING INDICIA ON SURFACE OF AN OBJECT WHICH COMPRISES AN ENCLOSED CHAMBER, MEANS FOR SUPPORTING THE OBJECT IN THE CHAMBER, A HORIZONTAL MAIN TRACK ON A WALL OF THE CHAMBER, A MAIN CARRIAGE TRAVELING ON SAID MAIN TRACK, A FRAME BAR MOUNTED ON THE MAIN CARRIAGE AND EXTENDING INWARDLY AND OUTWARDLY OF THE WALL OF THE CHAMBER, THE FRAME BAR EXTENDING THROUGH A HORIZONTAL SLOT IN THE WALL ADJACENT THE MAIN TRACK, AN UPRIGHT INNER TRACK MOUNTED ON THE FRAME BAR INSIDE THE CHAMBER, A SECOND CARRIAGE TRAVELING ON THE UPRIGHT TRACK, A SANDBLAST NOZZLE CARRIED BY THE SECOND CARRIAGE FOR TRAVELING TRANSVERSELY OF THE SURFACE AND DIRECTING A SANDBLAST TOWARD SAID SURFACE, AN UPRIGHT OUTER ASSEMBLY MOUNTED ON THE FRAME BAR EXTERNALLY OF THE WALL, AN UPRIGHT OUTER TRACK, A COUNTERWEIGHT MEMBER MOUNTED FOR UP AND DOWN MOVEMENT ON THE UPRIGHT OUTER TRACK, MEANS CONNECTING THE SECOND CARRIAGE WITH THE COUNTERWEIGHT MEMBER FOR UP AND DOWN MOVEMENT IN UNISON IN OPPOSITE DIRECTIONS, MEANS FOR DRIVING THE MAIN CARRIAGE BACK AND FORTH BETWEEN PREDETERMINED LIMITS OF MOVEMENT, SWITCH MEANS ACTUATED BY THE MAIN CARRIAGE AT EACH END OF THE TRAVEL THEREOF, THE UPRIGHT ASSEMBLY COMPRISING MEANS FOR DRIVING THE COUNTERWEIGHT