Illumination – Light source and modifier – Adjustable or repositionable light source or light source...
Reexamination Certificate
2000-02-11
2001-07-10
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Adjustable or repositionable light source or light source...
C439S375000, C439S654000, C200S051100
Reexamination Certificate
active
06257740
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a lamp for use in light strings and more particularly to a light bulb base used in conjunction with a socket that will continue to conduct electricity and keep the remainder of the string of lights lit even when one or more individual light bulbs are missing from the socket.
BACKGROUND OF THE INVENTION
Light strings having lights connected electrically in a series are well known especially around the holidays when such light strings are used for decorative purposes. Generally, the lights in the string are electrically in series rather than in parallel. One particular drawback to these types of light strings is that when a light bulb is removed from the socket, the entire series is rendered inoperable. Each light bulb within its respective socket completes the electrical circuit so when a light bulb is removed or the filament burns out within the light bulb, a gap is created in the circuit and electricity is unable to continue to flow through the circuit. When a “good” light bulb is inserted into the socket, it completes the circuit, thus allowing electricity to flow uninterrupted.
One solution that allows the circuit to continue to function without a light bulb being in the socket is found in U.S. Pat. No. 5,453,664, issued to Harris and entitled “Light String With Improved Shunt System”. The Harris patent is directed to a bulb shunt system that is configured to shunt the electric current passing through the light bulbs if a filament breaks or is removed from the socket.
The Harris system has a first shunt located inside the glass envelope of the light and a second shunt is located either in the lamp holder or in the socket. The combined resistance of the shunts is greater than the resistance of the light bulb therefore allowing the string to remain lit.
While the Harris device allows for the electrical current to continue if a light bulb is damaged and remains within the socket or if the light bulb is completely removed from the string of lights, it requires special light bulbs designed to include the first of the two shunts. This system also requires a second shunt system to be made within the socket, therefore creating an extra shunt to be present in every socket/light bulb combination. That is, only one shunt is utilized at a time and an extra or excess shunt is present in every lamp. Moreover, when a bulb is remove, such as when it has been burned out, without turning out the light, the shunt welds and thereby prevents the replacement bulb from lighting. Finally, as each socket's shunt welds, the voltage across the remaining lamps increases, thereby reducing the life of these bulbs, and causing a cascading of bulb breakdowns.
While the above stated devices are a fair representation of the current prior art, there remains room for improvement as defined by the currently claimed invention.
SUMMARY OF THE INVENTION
The lamp of this invention allows for the electrical current in a system to continue to flow when the light bulb base has been removed completely from the socket. This is accomplished by having a light bulb with filaments, mounted within a light bulb base. Two wires are connected to the filaments in the bulb and extend from the interior of the light bulb out through the bottom of the base. On the exterior of the base, the wires are bent outwardly and upwardly around the base. The bulb with its base is inserted into a light socket. Wires from a source of electricity enter the socket and make contact with two spring terminals, one on either side of the socket. These two spring terminals within the socket are biased toward one another. Therefore, unless separated, they would touch and would short the circuit by conducting electricity from one of the spring terminals to the other, thus continuing to conduct electricity without a load. The base of the light, however is modified to force the spring terminals apart when the light base is inserted into the socket. When the spring terminals are separated, electricity can flow through the light bulb, enabling it to light.
The present invention has numerous features and advantages associated therewith.
The lamp herein described has an advantage of keeping the remainder of lights within a string of lights lit when a light bulb is missing from one or more light bulb sockets. This is accomplished by continuing to conduct electricity through the light bulb socket even when a light bulb base is not present within the socket.
One unique feature of the light bulb socket is the two spring terminals that spring into electrical contact with one another when a light bulb base is not present in the socket. Due to the physical meeting of the two spring terminals, the opportunity for arcing is reduced. The electrical current flows from one spring terminal to the other and is never given the opportunity to arc.
The present light bulb base is easy to manufacture and use, thus making it economical.
The description of the present invention discloses, in conjunction with the drawings which illustrate by way of example, the principles and objects of the invention.
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patent: 4720272 (1988-01-01), Durand
patent: 5453664 (1995-09-01), Harris
patent: 5456620 (1995-10-01), Kaminski
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patent: 5860731 (1999-01-01), Martinez
patent: 5860830 (1999-01-01), Wu
Mann Michael A.
Nexsen Pruet Jacobs & Pollard LLC
O'Shea Sandra
Sawhney Hargobind S.
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