US2277348A - Lamp receptacle - Google Patents

Description

arch 24, 1942. w. E. PARISH 2,277,348 LAMP RECEPTACLE Filed Feb. 19, 1940 Patented Mar. 24, 1942 UNITED stares Grouse-Hinds Compan poration of. New York y, Syracuse, N. Y., a cor- Application February 19, 1940, Serial No. 319,708

3 Claims.

This invention relates to receptacles for the conventional electric lamp, or more particularly to the screw shell portion of such receptacles.

The invention has as an object a receptacle screw shell embodying a structure particularly economical to manufacture and which operates to yieldingly retain the base of the lamp in proper position in the screw shell under all conditions of vibration.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing in which like characters designate corresponding parts in all the views.

Figure 1 is a side elevational view of a lamp receptacle screw shell embodying my invention.

Figure 2 is a top plan view of the screw shell.

Figure 3 is a View taken on substantially line 3-3, Figure 1.

Figure 4 is an enlarged fragmentary view illustrating the action between the threaded base of the lamp and the screw shell.

The general object of the invention is the provision of means to prevent the lamp from becoming loosened or unscrewing out of the screw shell under conditions of excessive vibration. Heretofore, many constructions have been suggested to obtain this result. In receptacles of this type, Q

it is customary to arrange one or more spring members within the screw shell and which function to yieldingly press against the lamp base in order to retain it in the screw shell. This, and other structures to accomplish the result, adds materially to the cost of manufacturing the screw shell, and such structures are not entirely satisfactory.

The screw shell herein described is of cast metallic formation being formed with a radially extending flange I adjacent the open end of the shell, and with an inwardly extending arcuate flange II to which a disk I2 of insulating material is secured as by screws l3 extending through the disk and threading into apertures formed in the flange II. The particular screw shell illustrated is intended for use in fittings such as disclosed in Patent No. 2,174,773.

One side of the shell, adjacent the base thereof, is cut away to provide an aperture I4 of appreciable dimensions. The center contact I5 is secured to the under side of the disk I2 and extends over the peripheral edge thereof and inwardly to engage the center contact of the lamp base in the conventional manner.

The contact I5 is secured to the disk I2 as by screw I I, and the wire I8 is connected to the contact by being secured under a binding nut I9 threaded upon the screw. The opposite lead wire 20 is secured to the shell of the receptacle by screw ZI and nut 22.

The screw shell is formed with an internal thread 23 which is in form complemental to the thread on the base of the lamp, being however of a different pitch than the thread on the lamp base. Preferably the thread 23 is of lesser pitch than the thread on the lamp base. For example, the thread on the conventional medium lamp base is seven, while the pitch of the thread 23 is six and three-quarters. Accordingly, as the lamp base is threaded into the screw shell, the threads of the two members tend to bind because of the difference in pitch, and when the base is threaded into the screw shell a sufficient distance to effect proper contact between the central contact of the lamp and the contact l5, this binding effect is appreciable and I have found that the lamp will not loosen or unscrew out of the screw shell under any condition of vibration.

It will of course be understood that conventional electric lamps are manufactured and sold with five different sizes of bases known as Miniature having 14 pitch thread, Candelabra having 10 pitch thread, Intermediate having 9 pitch thread, Medium having 7 pitch thread, and Mogul having a 4 pitch thread. Accordingly, a screw shell comparable to any one of the conventional lamp bases will be formed with its thread of slightly different pitch than the pitch of the thread on the particular lamp base.

In order that there may be some resiliency in the screw shell to prevent excessive binding between the lamp base and the shell, particularly in connection with a heavy cast metallic screw shell, I form the screw shell with a plurality of slots extending inwardly from the open end of the shell toward the base thereof. There are four such slots shown in the accompanying drawing, the slots of each pair being arranged in alinement. The slots 25 are diametrically opposed, one of the slots being arranged centrally of the aperture I l. The second pair of slots 26 are arranged in opposite sides of the screw shell but spaced to one side of the center thereof, the arrangement being such that the slots 26 are arranged remote from the side portion of the screw shell in which the aperture 14 i formed. This specific arrangement is to effect substantially the same resiliency to each section of the shell, the

length of the sections varying because of the aperture l4.

What I claim is:

1. A metallic lamp receptacle screw shell formed with an internal thread to receive a threaded base of a conventional electric lamp, said internal thread being of different pitch than the thread on the lamp base, and said screw shell being non-yielding in axial direction and being formed with a plurality of radially yieldable sections.

2. A metallic lamp receptacle screw shell provided with an internal thread to receive the threaded base of a conventional electric lamp, said internal thread being of different pitch than the thread on the lamp base, said screw shell being non-yielding in axial direction and being formed with a plurality of slots extending from the open end of said shell toward the base thereof and forming radially yieldable sections.

3. A metallic lamp receptacle screw shell formed with an opening in one side adjacent the base thereof, diametrically opposed slots extending inwardly from the open end of said shell toward the base thereof, one of said slots extending into said opening, a second pair of opposed slots arranged in angular relationship to said first mentioned slots and remote from said aperture, said slots forming radially yieldable sections, said screw shell being provided with an internal thread to receive the threaded base of a conventional electric lamp, and said internal threads being of lesser pitch than the thread on the lamp base.

WILLARD E. PARISH.

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