Western Electric Co. v. Millheim Electric Tel. Co.

88 F. 505, 1898 U.S. App. LEXIS 2810
CourtU.S. Circuit Court for the District of Western Pennsylvania
DecidedJuly 18, 1898
StatusPublished
Cited by7 cases

This text of 88 F. 505 (Western Electric Co. v. Millheim Electric Tel. Co.) is published on Counsel Stack Legal Research, covering U.S. Circuit Court for the District of Western Pennsylvania primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Western Electric Co. v. Millheim Electric Tel. Co., 88 F. 505, 1898 U.S. App. LEXIS 2810 (circtwdpa 1898).

Opinion

BUFFINGTON, District Judge.

This is a bill filed by the Western Electric Company against the Millheim Electric Telephone Company et al. for alleged infringement of letters patent No. 449,106, issued March 31, 1891, to «John J. Oarty, for telephone circuit and apparatus, and now owned by complainant. The defenses are lack of novelty and patentability. These defenses failing, infringement is conceded. The apparatus in question was designed primarily for use on a multiple line. Prior to this patent it was customary to connect the call-bell magnets at the several stations in series in the main-line circuit together with a normally shunted call-sending generator, and at each station to provide, a switch, which, when at rest, maintained the continuity of the main circuit through .all the call-bell magnets, and kept the circuit of the local transmitter battery open. When, however, the switch was changed, — which was done when the receiver was taken from the hook for use, — it disconnected or short-circuited the bell magnet or generator from the line, and Introduced in place thereof the telephonic transmitting and receiving instruments, and closed the local battery circuit of the former. Though this switch change at the two communicating stations removed the bell magnets at such stations from the circuit, no such action took place at the other stations. Consequently, the voice current had to traverse all the other magnet helices in the line, and was much weakened, not only by the resistance of such magnets, but also by the counter electro motive forces or inductive resistances developed in each. These were so active and energetic as to hinder conversation; yet it was necessary that, all bell magnets should be connected with the circuit, otherwise the several stations cannot signal each other. It will be noted that in this system, which is called a “series circuit,” the component parts are so arranged that the current must pass through all its paria, one after another. It is so styled in contradistinction to a “multiple circuit,” which is one having two or [506]*506more of its parts so arranged that the current divides, portions of it passing through parallel paths afforded by the several parts. The two systems may be thus illustrated: When incandescent lights are connected in multiple circuit, the current passes to one terminal of each of the lamps which are connected to one side of a circuit, and then divides up, a portion passing through each lamp to the other side of the circuit, where all these portions are reunited. Where such lamps are connected in series, all the current must flow Into the terminal of the first lamp, and out at the other, and so on through (he successive lamps.

It also appeared impossible to obtain a perfect inductive balance in a metallic telephone circuit when the bell magnets and telephone were connected in series, and such inductive disturbances manifested themselves generally in annoyances, and sometimes were so intense as to prevent conversation. Now, it would seem that if, instead of the series circuit connection for both call magnets and telephones, a multiple circuit or bridging connection after the manner of the simplest form of incandescent lighting was substituted, these difficulties would be avoided; but the conditions were different, since in a telephone circuit each station is both a generating and a utilizing one at the same time. Therefore the generating currents are likely to be short-circuited by the nearest bridge connection, and thus fail to reach the more distant station which it is desired to signal. The additional fact that two diverse uses are to be made of the current at the same station, viz. signaling and transmission of sound, and that they are to be used interchangeably between all the stations, renders necessary the addition of other means and factors to simple mere parallel arrangements. To overcome these difficulties, the patentee suggested a simple and efficient remedy. He adopted the multiple circuit plan, and at each station placed a permanent bridge, in which he seated a bell magnet, with a high co-efficient of self-induction and of marked impedance. He also provided two other bridges, which were normally open, and closed only when the station was in use. The generator bridge circuit was adapted to be closed while a call was being sent. The third or telephone'bridge circuit was open when not in use, but closed in multiple arc with its own bell magnet, and, of course, with all others in the line, when in use. When the call generator is used at a station, it forms a second bridge or cross connection between the wires in parallel circuit with the permanently closed bridge circuit of its own bell and all other bells on the line. Now, the natural tendency of the ringing current would be to short-circuit through its home call-bell bridge, and possibly through the nearest other call-bell bridges. This, of course, is highly undesirable, as it is necessary that all of the call bells of the system should be operated by the call generator of each station. The tendency of the current to thus short-circuit is counteracted in Carty’s system by the high self-induction and impedance of the bell magnet which opposes the passage of the call current, and effects a more even distribution of it through the bell magnets of the system. By virtue of numerous windings of the wire in the bell magnets, the small portion of the call current passing exerts a marked magnify[507]*507ing effect on the cores, and thus secures a more spirited working of tlie call signal. The means employed in the device and the mode of operation are clearly stated by respondents’ witness, Mr. Miller, who says:

“I am acquainted with this patent. It shows and describes a method of attaching telephone instruments in multiple between the two sides of a line, whether this line be a metallic circuit or a grounded line. The call bells are each permanently bridged between the two sides of the line, and are made of high resistance and retardation. The generator at each instrument is in a separate bridge circuit, which is normally open, but closed when the generator Is operated. The telephonic apparatus proper, is in a third bridge circuit, which, like the generator circuit, is normally open. The telephone circuit of each instrument is automatically closed when the receiver is removed from its hook for use; and this operation also closes a local circuit containing the primary of the induction coil, the local battery, and the transmitter, in order that there shall not be an undue leakage of the voice currents through the permanently bridged call-bell circuits, the magnets of these call bells are wound to a high resistance (usually 1,000 ohms), and are also constructed in such maimer that they will ha.ve a high co-efficient of self-induction. When a generator at any one station is operated, it is connected across the two sides of the line in parallel with all of the call-hell magnets on the line. Part of the currents in this generator will therefore pass through each of the call-bell magnefs on the line, thus causing them all to operate if ihn amount of the current generated is sufficient to accomplish this result. The successful operation of this system depends on the fact that a. coil possessing a high co-efficient of self-induction will transmit with comparative ease alternating or pulsating currents of low frequency, while it will form a practical barrier to similar currents having a very high frequency.

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Bluebook (online)
88 F. 505, 1898 U.S. App. LEXIS 2810, Counsel Stack Legal Research, https://law.counselstack.com/opinion/western-electric-co-v-millheim-electric-tel-co-circtwdpa-1898.