Conductive pins for an illumination lamp

A conductive pin (4) for an illumination lamp is made of CuNi-alloy including by weight, 10-30% Ni and 70-90% Cu.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a current lead-in conductor for an 
illumination lamp with a glass base, which conductor is made of nickel 
(Ni)-containing alloy, and to an illumination lamp containing such a 
conductor. 
2. Description of the Prior Art 
Illumination lamps include incandescent lamps, gas discharge lamps, flash 
lamps and the like. An illumination lamp has a hollow glass body and a 
substantially massive or solid glass base connected with the hollow glass 
body. The current lead-in conductor is partially fused into the glass base 
and partially projects outwardly from the base. The current lead-in 
conductor is a heavy solid body made of an appropriate alloy. The known 
current lead-in conductors for the illumination lamps are made of an alloy 
consisting of 98% Ni by weight and 2% Mn by weight. Nickel is a rather 
expensive metal and, of course, it is desirable to be able to make the 
current lead-in conductors of a cheaper material. However, the current 
lead-in conductors should meet certain requirements which the desired 
cheap materials (substitute metals) should satisfy. These requirements 
are: 
The use of a substitute metal should not make the production of the current 
lead-in conductors more difficult. 
The substitute metal should, during fusing-in of the conductor into the 
glass base, withstand the fusing temperatures of about 1,200.degree. C. 
The substitute metal should have a good electrical conductance to insure 
current supply into the interior of the illumination lamp. 
The substitute metal should have a good heat conductance to be able to 
carry away heat from the lamp interior. 
The substitute metal should be able to withstand operational temperatures 
of 150-200.degree. C. which prevail at the outwardly projecting portion of 
the current lead-in conductor. 
The substitute metal should have a very good corrosion resistance in the 
presence of oxygen and heat. 
Accordingly, an object of the present invention is to provide a relatively 
cheap metallic material for making the current lead-in conductors which 
would meet all of the above-listed requirements. 
SUMMARY OF THE INVENTION 
This and other objects of the present invention is achieved by using for 
making the current lead-in conductors a Ni-containing alloy comprising 
10-30% Ni by weight and 70-90% Cu by weight. 
Because of the high content of copper the alloy, which is used for 
producing the current lead-in conductors, is rather cheap, e.g., 20% 
cheaper than alloy including 98% of nickel or pure nickel. Extensive 
experiments have shown that the current lead-in conductor made of 
CuNi-alloy having high content of copper is still capable of meeting all 
of the production, fusing and operational temperatures, and corrosion 
resistance requirements as well as the requirements with regard to 
electrical and heat conductance. While the current lead-in conductor 
according to the present invention, because of properties of the alloy it 
is made of, has somewhat lower values of the electrical and heat 
conductance than the conventional current lead-in conductors made of 
NiMn-alloy, both the electrical conductance and the heat conductance of 
the CuNi-alloy of which the current lead-in conductors according to the 
present invention are made, are still very much acceptable. 
The CuNi-alloy is per se known and is available on the market. The alloy of 
which the current lead-in conductors according to the present invention is 
made can contain other metals, e.g., up to 10% by weight, e.g., Fe and/or 
Mn. The best characteristics of the current lead-in conductor according to 
the present invention are achieved when the CuNi-alloy of which the 
conductor is made, contains maximum 20% Ni by weight. 
Generally, the current lead-in conductor according to the present invention 
is made of a drawn wire and has a diameter up to 4 mm and a length up to 
400 mm. The known current lead-in conductors also have these dimensions. 
As a rule, the current lead-in conductor according to the present invention 
is welded, at an end thereof extending in the glass base to a lead-in 
wire. 
The current lead-in conductor and the a lead-in wire form together a 
current lead-in, which itself is finished product. The lead-in wire is 
made e.g., of molybdenum, tungsten or a FeNi-wire having a copper packet 
(DUMET.TM.). 
The current lead-in conductor according to the present invention is 
relatively easy welded to the lead-in wire. The lead-in wire is partially 
fused-into the lamp glass base and projects into the interior of the lamp.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
An illumination lamp according to the present invention, which is shown in 
the drawing has a hollow glass body 1 which smoothly passes into a massive 
glass base 2. Two current lead-ins 3 are cast-into the glass base 2. Each 
lead-in 3 consists of a current conductive pin 4 and a lead-in wire 5 the 
cross-section of which is smaller than that of the conductive pin 4. The 
adjacent ends of the conductive pin 4 and the lead-in wire 5 abut each 
other and are connected with each other by a weld 6. Both sealed pins 
project into the glass body 1, with their free ends carrying a filament 7 
made of tungsten. 
The conductive pin 4 itself is formed of a copper-nickel alloy having 
10-30% of nickel by weight and 70-90% of copper by weight. The conductive 
pin 4 are formed of sections of drawn wire and have a diameter up to 4 mm, 
and a length up to 400 mm. 
Though the present invention was shown and described with reference to the 
preferred embodiment, various modifications thereof will be apparent to 
those skilled in the art and, therefore, it is not intended that the 
invention be limited to the disclosed embodiments or details thereof, and 
departure can be made therefrom within the spirit and scope of the 
appended claims.