US2736874A

US2736874A - Electric lamp

Info

Publication number: US2736874A
Application number: US263458A
Authority: US
Inventors: Conrad E Bechard; Waldemar P Schoenoff
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1951-12-26
Filing date: 1951-12-26
Publication date: 1956-02-28
Anticipated expiration: 1973-02-28

Description

Feb. 28. 1956 c. E. BECHARD ET AL ,7

ELECTRIC LAMP Filed Dec. 26, 1951 Inventors Conrad Ebechord Waldemar P. Schoenoff ywc WM Their Attorney United States Patent ELECTRIC LAIVIP Conrad E. Bechard, Mayfield Heights, and Waldemar P.

Schoenoif, Euclid, Ohio, assignors to General Electric Company, a corporation of New York; patent dedicated to the Public insofar as it relates to lamps and lamp parts to the extent stated in document recorded in the U. S. Patent Ofiice, January 4, 1954, Liber U-238,

page 394 f Application December 26, 1951, Serial No. 263,458

1 Claim. 01. 339-146) This invention relates generally to electric lamps and their manufacture and more particularly to the operation commonly known as basing, wherein a metal base is fastened to the neck of the bulb, the lead-in wires are connected to the appropriate parts of the base, and the projecting portions of lead-in wires are removed.

In the commercial production of incandescent lamps, basing is generally made with a finishing machine which comprises a turret or reel having a number of holders mounted on its periphery and in which the bulbs are supported with their bases properly seated on them. Means are provided for intermittently rotating the reel in order to index the bulbs into successive work stations where the various operations are performed automatically for completing the manufacture. The common practice is for the operator to apply the base to the bulb neck and to thread the lead wires, one through the eyelet hole in the end contact of the base, and the other along the side of the bulb neck, previous to inserting the lamp into a holder of the finishing machine. In general, the prior art manufacturing operations included heating the base by suitable means such as gas flames in order to set the basing cement, cutting oif the projecting portions of the lead wires, and connecting the lead wires to the base shell and to the eyelet. The lead-in wires were generally connected by soldering.

More recently it has been proposed to eliminate the solder connection of the side lead-in wire and to substitute in its stead a mechanical connection. It will be appreciated that a solder connection requires theme of a readily soldered metal such as brass for the shell of the base, and that a mechanical connection has the decided advantage of permitting the substitution of less expensive materials such as aluminum. he invention is more particularly concerned with the basing of lamps wherein the side lead-in Wire of the lamp is wedged between the seal shoulder or neck of the bulb and the shell of its base in order to effect a mechanical contact. With such lamps, it is highly desirable that the side lead'in wire be cut off very short. A projecting length of relatively stifi wire is unsightly and also hazardous from the point of view of scratching of the hands in handling. Moreover, the public has become accustomed to incandescent lamps having a soldered side connection, and now tends to regard a lamp having a short length of lead wire projecting from the edge of the base and not soldered, as defective. That tendency is not present when the lead-in wire is cut off right at the edge of the base so that no part thereof appears on casual inspection.

Accordingly, an object of the invention is to provide a new and improved electric lamp of pleasing appearance and having its side lead-in Wire cut off so short that no part thereof is visible upon casual inspection of the lamp.

-In accordance with the invention, the side lead-in wire is first wedged between the seal of the bulb and the shell of the base so that any subsequent pulling on the protruding portion of the wire will not exert excessive tension on the lead-in wire where it is hermetically sealed into the bulb. Thereafter the protruding portion of the wire is' sheared ofi against the edge of the base shell by pulling the wire back in a manner to effect a sharp bend in it at the edge of the shell. Where the lead-in wire is too heavy to be sheared by the shell, a blade may be positioned against the edge of the shell in order to reinforce it during the shearing operation.

For further objects and advantages and for a better understanding of the invention reference may be made to the following description and to the accompanying drawings forming a part of this application and wherein:

Figs. 1 to 3 illustrate diagrammatically successive steps in the cutting 01f of the side lead-in wire and Fig. 3 shows a fragment of a lamp embodying our invention.

The invention will be described with reference to an ordinary screw base such as is widely used for household incandescent lamps. It will be understood however that the invention is equally applicable to difierent sizes and types of bases; for instance the invention may be used with bayonet type bases where the side lead-in wire is connected to the straight-walled cylindrical shell of the base.

Referring to the drawing, the successive steps in the basing of a lamp and the shearing off of the side lead-in wire in accordance with our invention have been diagrammatically illustrated. In Fig. l, a base 1 has been placed over the neck 2 of an electric lamp bulb whereof a fragment 3 has been illustrated. The base comprises a threaded metal shell 4, a metal end contact 5, and an insulating body or web 6 holding the metal parts together. The top lead wire 7 of the bulb is threaded through the eyelet hole 8 in the end contact, and the side lead wire 9 is curved around the neck portion 2 of the bulb and the projecting portion 9' is pulled out at right angles to it below the edge of the base shell. The seal shoulder 10 of the bulb is preferably blown or molded to a size substantially the inside diameter of the skirt of the base shell, so that the side lead wire is wedged between the neck and the base shell at 11.

In Fig. 2, the projecting portion of the side lead-in wire has been gripped between a pair of

jaws

12, 13 which pull the wire upward along the side of the base. The wire is thus bent around sharply below the edge of the shell so that it is stretched and weakened at the point 14 due to the reversal of its direction as between its portions inside and outside the shell. By reason of the fact that the wire is wedged between the base shell and the neck of the bulb, very little stress is transmitted past the point 11 and the possibility of rupturing the seal of the inner portion of the lead into the glass of the bulb is obviated. Moreover by reason of the direction in which the pull is exerted on the wire, the edge of the base shell acts as a knife which effectively shears oil the wire without requiring the application of excessive force upon it. The final step in the shearing operation is illustrated in Fig. 3 wherein the lead wire is broken off at the point 14 and the portion 9' is carried away by the aws.

As illustrated in Fig. 3, our invention provides an electric lamp of pleasing appearance and wherein the side lead-in wire is sheared off at the very edge of the base shell with a sharp bend partly around said edge just preceding the end of the wire and with the end of the wire lying against said edge. Thus no part of the side lead-in wire is observable upon casual inspection of the lamp, and the connection of that wire to the shell of the base is entirely internal and results from the fact that the wire is wedged between the seal shoulder of the bulb and the skirt of the base shell. The need for rolling 3 back the projecting portion of the lead Wire against the edge of the shell or for brushing it into the crack between the edge of the base and the neck of the bulb is completely eliminated.

In the case of the larger sizes of incandescent lamps, the side lead-in wire, which is generally fuse wire, may be too heavy to allow for shearing against the edge of the base without support. In such case, the edge of the base shell may be reinforced for the shearing operation by positioning a sharp blade next to it in a manner to take up some of the shearing stress as indicated by the blade 15 shown in dot-dash lines in Fig. 1.

What We claim as new and desire to secure by Letters Patent of the United States is:

An electric lamp comprising a vitreous bulb having a neck portion and a lead-in wire emerging therefrom, a base comprising a generally cylindrical metal shell fastened to said neck portion, a seal shoulder in said neck portion having a diameter closely conforming to the inside diameter of the skirt of said shell to achieve a close fit therewith, said lead-in wire extending between said shoulder and said shell and being wedged between said shell and said shoulder, said lead-in wire being terminated at the point of emergence thereof from under the edge of said shell with a sharp bend partly around said edge just preceding the end of the wire and with the end of the wire lying against said edge, and with no portion of said wire projecting visibly beyond said edge.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,317 Blake et a1. Jan. 5, 1937 2,069,386 Palucki Feb. 2, 1937 2,077,199 Asmussen Apr. 13, 1937 2,342,041 De Bold Feb. 15, 1944 2,359,483 Kuebler Oct. 3, 1944 2,390,139 Vasselli Dec. 4, 1945 2,403,137 Strickland July 2, 1946