Edison Electric Light Co. v. Electric Engineering & Supply Co.
| Decision Date | 14 February 1895 |
| Citation | 66 F. 309 |
| Parties | EDISON ELECTRIC LIGHT CO. v. ELECTRIC ENGINEERING & SUPPLY CO. |
| Court | U.S. Court of Appeals — Second Circuit |
R. N Dyer and C. E. Mitchell, for complainant.
Alfred Wilkinson, for defendant.
Before WALLACE, LACOME, and SHIPMAN, Circuit Judges.
The suit was brought on five patents, viz: No. 265,311, to Edison; No. 251,596, to Johnson; and Nos. 257,277, 293,552 and 298,658, to Bergman. All these patents relate to sockets for incandescent electric lamps. The patent to Edison, No 265,311, was held valid by the circuit court, and was also found to be infringed, but, because of the expiration of a Russian patent to Edison for the sam invention, no injunction was granted. No appeal from that part of the decree was taken. The patent to Johnson, No. 251,596, was held by the circuit court to be invalid as to the claim in controversy. The complainant appealed, but upon the argument in this court the decree of the circuit court as to that patent was sustained on the opinion below. The third patent to Bergman, No. 298,658, was withdrawn at the argument from the consideration of the circuit court, and from so much of the decree as dismissed the bill as to that patent no appeal was taken. The second patent to Bergman, 293,552, was held valid by the circuit court, which decreed an injunction and accounting thereon. The defendant appealed, but upon the argument in this court the decree of the circuit court as to that patent was sustained on the opinion below. The first patent to Bergman, 257,277, was held valid by the circuit court as to the second claim, the only one of which infringement is charged. The defendant has appealed, and the determination of that appeal is the only question remaining to be decided by this court.
This first Bergman patent is one for an improvement in the details of an incandescent lamp socket, devised to overcome a difficulty which was found to exist in the earlier combinations of lamp and sockets. The lamp, which comes separate from the socket, is a glass bulb, surrounding the illuminating filament. Through the insulating material which closes the mouth of this bulb, and constitutes its base, run the leading-in wires which carry the current to the filament. Each of these leading-in wires is connected with a piece of metal on the outside of the lamp base, these pieces of metal being separated from each other by insulating material. When the base of the bulb is inserted in the socket, these pieces of metal come into contact, respectively, with the two wires which bring the current from the source of supply. When both are thus in contact, the current flows through the filament. When one of them is cut off from contact, by a key or other circuit-breaking device, the current ceases to flow, and the light is extinguished. Prior to Bergman's contrivance the two pieces of metal which connected at the lamp base with the leading-in wires consisted of a screw-threaded band around the base near its lower end, and a broad flaring ring nearer to the bulb. The band engaged with screw-threaded metal in the socket, thus making electrical connection with one of the line wires. The flaring ring engaged with a like ring on the top of the socket, thus making connection with the other line wire. The insulating material of the base of the lamp, which formed a nonconducting body between the band and the flaring ring, was composed of plaster of paris. As the lamp base was screwed down into the socket so as to bring the two rings into proper contact, there was a constant tendency to pull the base apart between the screw-threaded band and the ring; and, as plaster of paris is a fragile material, it frequently happened that the insulating surface was cracked or disintegrated before the filament of the lamp was worn out. Bergman reversed the position of these metal contacts in both lamp and...
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