Apparatus for coating glass bulbs

Claim 1

APPARATUS FOR ELECTROSTATICALLY COATING THE INTERIOR SURFACE OF AN ENVELOPE HAVING A BULBOUS PORTION, A NARROWER NECK PORTION, AND AN OPEN END, SAID APPARATUS COMPRISING A ROTATABLE HEAD FOR SUPPORTING SAID BULB LOOSELY AT ITS OPEN END TO ALLOW PASSAGE OF AIR INTO SAID BULBOUS PORTION THROUGH THE OPENING IN SAID NARROWER NECK PORTION, A SPRING ELECTRODE IN POSITION TO CONTACT SAID BULBOUS PORTION, A SOURCE OF HIGH VOLTAGE, A FIRST ELECTRODE CONNECTED TO ONE TERMINAL OF SAID SOURCE AND ELECTRICALLY CONTACTING SAID BULB, A SLEEVE PROJECTING FROM SAID HEAD INTO SAID BULB, A SMOKE TUBE RECIPROCABLE WITHIN SAID SLEEVE FOR INTRODUCING COATING MATERIAL IN THE FORM OF SMOKE INTO SAID BULB, AN ELECTRODE CARRIED BY SAID SMOKE TUBE AND CONNECTED TO THE OTHER TERMINAL OF SAID HIGH VOLTAGE SOURCE, SAID SMOKE TUBE AND ELECTRODE BEING DISPOSED AND RECIPROCABLE WITHIN SAID SLEEVE, A VACUUM CHAMBER IN COMMUNICATION WITH THE PASSAGE BETWEEN SAID SMOKE PIPE AND THE INNER WALL OF SAID SLEEVE, AND MEANS SPACING THE INNER WALL OF SAID BULB FROM THE OUTER WALL OF SAID SLEEVE IN THE NECK PORTION OF SAID BULB AND SUBSTANTIALLY ABOVE THE OPEN END OF THE BULB TO PERMIT THE FLOW OF AIR ALONG SAID INNER WALL OF SAID BULB TO DETERMINE AND LIMIT THE AREA OF DEPOSITION OF SAID COATING MATERIAL ON SAID INNER WALL.