Latour Corporation v. EB Latham Co.
| Decision Date | 11 January 1934 |
| Citation | 23 F. Supp. 869 |
| Parties | LATOUR CORPORATION v. E. B. LATHAM CO. |
| Court | U.S. District Court — Southern District of New York |
Pennie, Davis, Marvin & Edmonds, of New York City, and William H. Davis, of New York City, and William H. Taylor, of St. Albans, L. I., N. Y., for plaintiff.
Cooper, Kerr & Dunham, of New York City, and Drury W. Cooper, of New York City, Cornelius D. Ehret, of Philadelphia, Pa., and C. Blake Townsend and H. Frank Wiegand, both of New York City, for defendant.
The bill of complaint alleges the infringement of Claims 1, 11, 15 and 18 of Reissue Patent No. 16,461, and Claims 9 and 11 of Patent No. 1,614,136, granted to the plaintiff as assignee of Marius C. A. Latour.
The suit is defended by Atwater Kent Manufacturing Company which manufactured the defendant's accused Atwater-Kent Receiver Model No. 35.
The reissue patent relates to a radio broadcast receiver combining multi-stage radio frequency amplification, detection and audio frequency amplification, a common B battery supplying current to the plate circuits of the high frequency amplifier tubes, the detector tube and the low frequency amplifier tube or tubes, shunting capacities (condensers) arranged to divert the high frequency current from the low frequency amplifier and stabilizing resistances connected in parallel either on the primary or secondary coils of the high frequency transformers.
The condensers and resistances are introduced into the combination to increase the stability of the receiver, being made necessary by the fact that multi-stage radio frequency amplification has a tendency to self-generation of disturbing high frequency oscillations. The condenser diverts the high frequency current from directly entering the audio frequency amplifier. The resistances have the effect of consuming energy and damping the high frequency current in each stage of amplification, thereby making possible greater total amplification, without the production of disturbing oscillations, than could otherwise be obtained.
The claims of the reissue patent in suit read as follows:
Claim II, a method claim, reads as follows: "In a system consisting of a plurality of thermionic relays of the audion type arranged in cascade, the method of receiving radio signals and of obtaining a higher degree of amplification of such signals than is possible with amplification at frequencies of one order of magnitude only with a minimum of current sources for said relays and without the occurrence of disturbing noises, which comprises introducing reactions opposing the production of disturbing high frequency oscillations in the system, successively amplifying the signal current at high frequency to a higher degree than would be possible without the production of oscillations in the absence of said opposing reactions, detecting the amplified high frequency signal current, amplifying the detected signal current at low frequency, supplying space current to all of said relays from a common source, diverting high frequency current from the low frequency circuits, whereby the production of high frequency oscillations through the use of said common source is substantially prevented, and translating the amplified low frequency current into sound waves."
Claim 15, also a method claim, reads as follows: "In a system consisting of a plurality of thermionic relays of the audion type arranged in cascade, the method of receiving radio signals and of obtaining a higher degree of amplification of such signals than is possible with amplification at frequencies of one order of magnitude only, without the occurrence of disturbing noises, which comprises introducing damping to prevent disturbing high frequency oscillations in the system, successively amplifying the signal current at high frequency to a higher degree than would be possible without the production of oscillations in the absence of said damping, detecting the amplified high frequency signal current, amplifying the detected signal current at low frequency, preventing high frequency current from affecting the low frequency amplifying step and translating the amplified low frequency current into sound waves."
Claim 18 reads as follows: "A thermionic relay system for receiving radio signals wherein a higher degree of amplification of such signals is obtained than is possible with amplification at frequencies of one order of magnitude only, without the occurrence of disturbing noises, comprising a plurality of transformer-coupled thermionic relays of the audion type in cascade circuit arrangement, resistance damping means associated with certain of said transformers for introducing reactions opposing the production of disturbing high frequency oscillations in the system, means including a certain plurality of said circuits, transformers and relays for successively amplifying the signal current at high frequency to the highest degree possible without the production of disturbing oscillations which tend to be produced in spite of said means introducing opposing reactions, means including one of said relays with its circuits for detecting the amplified signal current, a thermionic relay for amplifying the detected signal current at low frequency, and means for translating the amplified low frequency signal current into sound waves."
The Atwater-Kent receiver model No. 35 combines all the elements claimed: multistage radio frequency amplification, detection, audio frequency amplification, damping resistances, a common B battery supplying current to the plate circuits of all the vacuum tube relays and a by-pass condenser arranged to keep the high frequency current out of the low frequency amplifying stages.
Latour's condenser 12 shunts only the terminals of the primary coil of the audio frequency transformer. The Atwater-Kent condenser C 10 shunts the plate and filament of the detector tube. It also shunts the B battery as well as the primary coil of the first audio transformer. It thus keeps the high frequency currents out of the primary coil of the audio transformer and also out of the B battery. Latour's condenser keeps the high frequency current from directly entering the audio frequency transformer but not out of the battery. Both shunt the primary windings of the transformer and prevent or reduce the disturbing oscillations which would result if the high frequency current were permitted to flow directly into the audio-frequency amplifier. The defendant's condenser by also keeping the high frequency current out of the battery is an improvement over Latour's condenser but does not avoid his claim.
The defendant contends that because Latour's condenser does not keep the high frequency current out of the battery the tendency to the production of disturbing oscillations will be increased, contrary to what Latour sought to accomplish by his condenser and contrary to what he claims. It appears that if Latour's B battery should run down disturbing oscillations would be produced, whereas in defendant's device the additional by-passing of the battery by the condenser eliminates this difficulty. However, under normal conditions of operation in both Latour's and defendant's condenser connection the tendency to produce disturbing oscillations is reduced by keeping the high frequency current from directly entering the low frequency amplifier. Condenser C 10 of the defendant's receiver corresponds to condenser C 12 in Latour's even though it does something more.
The defendant's stabilizing resistances are associated with the secondary coils of the radio frequency transformers. Latour's drawings show resistances associated with the primary coils of the radio frequency transformers. Latour's specification, however, states "a resistance 16 will be then connected in parallel either on the primary or secondary of the high frequency transformers in order to introduce the necessary damping."
The evidence establishes that defendant's resistances are in parallel with the secondary coils, though they have the fixed grid-filament capacities of the respective vacuum tubes in series with them.
Claims 11 and 18 specify damping means for "introducing reactions opposing the production of disturbing high frequency oscillations." The defendant contends that resistances 16 can never introduce reactions and that the claims are therefore void or not infringed. It is evident that the word "reactions" was used to describe the effect of the resistances. But this is at most a question of choice of language. It is evident that by reactions resistances were meant.
Claim 18 specifies means "for successively amplifying the signal current at high frequency to the highest degree possible without the production of disturbing oscillations." Defendant urges that neither Latour's nor its receiver does this.
In the specification of the patent it is stated: "The object of the present invention is to indicate a process enabling the number of successive amplifications that may be effected in practice to be increased for the purpose of reception in wireless telegraphy.", and "Then when the maximum number of high-frequency...
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