Forming tool for lamp bases

Abstract

A method of manufacturing a flash-free lamp base (10), wherein the lamp base (10) comprises a shell (14), an eyelet (16) and a glass, electrically insulating part (18) therebetween and joining the shell (14) and the eyelet (16), the shell and the eyelet being electrically conductive, the shell (14) having a tubular portion (14a) with an open end (14b) and a partially closed end (14c) defining a volume (14d) therebetween, the partially closed end (14c) including a tapered area (14e) terminating in a reentrant section (14f) that extends into the volume (14d) and defines an inner annulus (14g). The method of making the base comprises the steps of positioning the shell (14) and the eyelet (16) at a workstation (19) in spaced, axial alignment with one another defining a gap therebetween; actuating a first forming tool (20) through the tubular portion (14a) and into engagement with the tapered area (14e) and the inner annulus (14g); dispensing a quantity of molten glass (32) into the gap; and actuating a second forming tool (22) within the first forming tool (20) to form the molten glass (32) into an electrically insulating part (18) between the shell (14) and the eyelet (16). The base so formed is free from extraneous glass flashing and thereby provides a base less likely to contaminate the lamp manufacturing process.

Dependencies are inferred from the claim text.