Method of manufacturing a bulb for a cathode-ray tube, and bulb obtained by means of this method
AssigneeU.S. Philips Corporation
InventorsJohan J. H. Bogaard, Gerrit-Jan Korteling
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Abstract
An envelope for an oscilloscope tube is formed by simultaneously rotating and heating a glass tube and upsetting the heated tube, to form a cylindrical section having uniform thickness and varying diameter. The thus formed envelope portion is then pressed into a shape having a rectangular cross-section, without changing the circumference, in order to maintain the thickness of the envelope.
Claims5
A method for manufacturing a bulb having a cylindrical neck joined to a polygonal section, comprising heating a central portion of a glass tubing to its softening temperature while rotating said glass tubing about its axis at a rate such that the softened portion of the tubing radially expands, simultaneously upsetting said softening of said glass tubing by axially displacing the end portions of said glass tubing at a rate to maintain the wall thickness of said central portion substantially constant, then stopping the rotation of said glass tubing and reshaping the radially expanded portion thereof to have a polygonal cross-section without varying the circumferential dimension of said radially expanded portion, and then cooling said reshaped glass tubing.
Dependencies are inferred from the claim text.