Patent Application
20080054780
The single FIGURE is an elevational, cross-sectional view of a lamp base according to an aspect of the invention.
For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings.
Referring now to the drawing with greater particularity, there is shown in the FIGURE a lamp base 10, for example, for a tungsten-halogen lamp. The base 10 comprises three electrically conductive parts or elements and a glass insulator. Specifically, the lamp base 10 comprises a first metallic outer part 12, a glass inner part 14, an electrically conducting eyelet 18, and an upper electrically conductive part 20, all symmetrically arrayed about a longitudinal axis 16. The glass insulator 14 bonds all of the electrically conductive parts, 12, 18 and 20.
The metallic outer part 12 is preferably threaded for insertion into a socket and has a major, internal diameter D1. The glass inner part 14 has a primary, external diameter that is equal to the major internal diameter D1; i.e., the external diameter of the glass inner part 14 is contiguous with the internal diameter of the metallic outer part 12. Further, the internal glass part 14 has an opening 14a therein and the opening 14a has a secondary diameter D2. In an aspect of the invention, D2/D1 is greater than 0.5 and less than 0.6 and, in the preferred embodiment of the invention, the ratio D2/D1 is 0.58.
In prior art lamp bases it was usual for the ration D2/D1 to be 0.47, resulting in a much greater amount of glass being utilized and leaving no room for a printed circuit board.
In part to maintain sufficient strength for the base 10, the draft angle for the opening 14a was decreased from 3° to 2°. The metallic outer part 12, which is usually referred to as the shell, is made from aluminum or brass having a thickness of 0.010″ (0.254 mm) and is quite fragile until assembled with its glass interface.
Thus there is provided a base for a lamp, which base is rugged and capable of accepting a printed circuit to increase the efficiency of a lamp.
While there have been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention as defined by the appended claims.
