Masking apparatus and method

Claim 1

AS A STEP IN THE MANUFACTURE OF AN ELECTRIC LAMP HAVING AN ENVELOPE WITH A CONSTRICTED NECK PORTION, THE METHOD OF MASKING A SELECTED INTERIOR PART OF SAID ENVELOPE GREATER IN AREA THAN THE CROSS-SECTIONAL AREA OF SAID NECK PORTION BUT SMALLER THAN THE MAJOR LATERAL DIMENSION OF SAID ENVELOPE WHICH METHOD COMPRISES; PROVIDING A RESILUENT MAGNETICALLY-RESPONSIVE SHIELD OF SUBSTANTIALLY THE SAME CONFIGURATION AS THE SAID SELECTED INTERIOR PART OF SAID ENVELOPE TO BE MASKED; CONTORTING SAID SHIELD TO TEMPORARILY REDUCE ITS LATERAL DIMENSION TO ONE SMALLER THAN THE INNER DIMENSION OF SAID NECK PORTION; INSERTING SAID SHIELD WHILE SO CONTORTED THROUGH SAID NECK PORTION AND INTO THE ENVELOPE PROPER; RELEASING SAID SHIELD; PLACING SAID ENVELOPE AND THE FREELY-CONTAINED SHIELD IN A MAGNETIC FIELD OF SUCH CONFIGURATION AND INTENSITY THAT SAID SHIELD IN RESPONSE TO SUCH FIELD IS ATTRACTED TOWARD AND THEN PRESSED INTO MASKING ENGAGEMENT WITH THE SAID SELECTED INTERIOR PART OF SAID ENVELOPE TO BE PROTECTED. AND THEN, ARTER THE EXPOSED INTERIOR SURFACE OF SAID ENVELOPE HAS BEEN PROCESSED, CONTORTING AND WITHDRAWING SAID SHIELD FROM SAID ENVELOPE THROUGH SAID NECK PORTION.