98 F. 105 | U.S. Circuit Court for the District of Eastern New York | 1899
Tlie question is wb.etb.er the defendant infringes the first and fourth claims of letters patent issued to Elihu Thomson in 1883. The patent is for a combination, which carries the concession that each part is old (The Corn-Planter Patent, 23 Wall. 181, 224, 23 L. Ed. 161); and such is the fact. The parts are a switch, a magnet, an electric circuit, and the specifically avowed purpose of the patent is to prevent damage when the circuit is broken. The occasion for such preservation arises from the fact that when an electric circuit is broken, and the conductors are left proximate to each other, an arc forms, and passes from one conductor to the other: and, if the electrical current be sufficient, the ends of the conductors will be burned, and thereby deteriorated. Hence economy requires the earliest elimination of the arc; and in fact it may be dispersed so quickly by a magnet as to seem to have been nonexistent, the constant and obvious condition being that the magnet shall be of suitable power, and placed in proximity to the conductors. Since 1889 the magnet has been used to a large extent to disperse or to prevent the injurious arcs that otherwise form in breaking the circuits in the operation of trolley cars. In no other industry does the magnet appear to be used for the destruction or the prevention of the arc. Hence its present chief industrial use arose some six years after the issue of the letters, and, what is not important, its existing value in connection with trolley cars was not conceived by the inventor. While the patented combination did not go into any substantial use until some six years after the letters were issued, its use in connection with trolleys is, and since 1889 has become, extensive and valuable. The inventor, Prof. Thomson, applied the combination to a structure of his own, which structure was in other respects valuable, and the subject of patents. The structure lias obtained a wide sale and use, as have other structures involving the art in question. Undoubtedly the use of the magnet in the manner and for the purpose stated has been an important factor in producing such sales, but it is considered that the development of the structures admitting of its use has made its value available. The defendant does not use the complainant’s structure in the controllers connected with its cars, but does use the magnet to avoid the destructive influences of the arc. A precise survey of the complainant’s claims and contentions, and an adequate examination of the state of the art previous to Thomson’s alleged invention, are necessary. Claims 1 and 4 are as follows:
“(1) The combination, with an electric switch or commutator, of a magnet placed in proximity to the switch-contacts, or to surfaces between which a spark or flash is liable to occur, substantially as and for the purpose set forth.”
“(4) The combination, with the contact points or surfaces in an electric switch or commutator, of suitable means for producing a magnetic field in proximity thereto, which field shall act by its attractive or repulsive influence to diffuse or displace any electric arc or current that may pass or tend to pass at the instant of break or commutation.”
The complainant’s interpretation of these claims deserves attention. The learned counsel for the complainant states that the invention — •
“Is the combination of means for producing a magnetic field -with the contact-points of an electric switch for the purpose of accomplishing new results,*107 namely. vf il', preserving the switch structure. and particularly the contact points, from being burnt or injured’; (2) making a switch for use Aviüi considerable potentials a more compact, structure; (S) making a switch capable of safely operating with higher potentials than had been previously possible.”
Again it is slated that the invention—
“Consists of the combination, in an electric circuit of considerable potential, of a magnet, with and in proximity to the contact-surfaces of a switch, ‘substantially as and for the purpose set forth,’ to wit, to protect such contact-surfaces, to keep them clean, to prolong their life, and to enable them to be used with a higher potential current than would otherwise be possible.”
Again it is said;
“What he [Thomson] discovered, and what previous to his discovery no one liad known, ivas that an electric current of sufficient potential to generate a dangerous and damaging arc between the contact-points of a switcli could, by the combination with and action of a magnetic held at those contacts, be deprived of its damaging properties, and could be ‘moved on’ so> quickly that injurious results would not follow. Ilis now structure was a switch combined with a magnetic field, in and by which this conception and discovery was utilized, with the result that such combined switch and magnet was not only more durable, and capable of use with currents of higher potential than any previously known switch, but was more compact, and required less separation of the contact-surfaces than any switch previously invented.”
The accuracy of these contentions may be tested by turning to the letters patent, and gathering the expressed conception of the inventor. The specification states that the patentee has—
“Invented certain now and useful improvements in electric commutators or switches.” and that the “invention relates to switch or commutator devices for breaking, changing, or shifting electric circuits, and more particularly to switches or commutators designed for use in connection with electric-lighting systems, although it is not confined to devices used in such connection, but is intended to include electric switches or commutators generally when used in combination with circuits designed to carry currents of considerable electromotive force, or of sufficient electro-motive force to cause a tendency to the formation of electric; arcs across the switch-contacts on breaking circuit, or when used in connection with any other apparatus sued) that there is a tendency to the formation of arcs or sparks at the switch or commutator surfaces. The object of my invention is to increase the durability of electric switches or commutators, and to prevent damage thereto from the causes mentioned. More specifically, my invention is designed to prevent damage to the commutator brushes and segments by the formation of ares or sparks at the commutators of dynamo-electric machines, and likewise to lessen the tendency to short-circuiting of the armature-coils by the residuary spark of rupture. To these ends, my invention consists in combining with the contact surfaces or points for an electric switch or commutator suitable means for producing a magnetic field in proximity to the contact-surfaces, — -such, for instance, as a magnet whose, poles are placed near to the said contact surfaces or points, so as to break, displace, or disperse any electric spark or arc that may form or tend to form at such contacts; said magnet acting for this purpose by virtue of the tendency of an arc or heated conductor to move out of or into a magnetic field, according to its direction. My invention consists, also, in the combination, with the commutator for a dynamo-electric machine, of a magnet or magnets, or their equivalent, a conductor conveying an elec crie current, placed in suitable proximity to said commutator at points immediately following those at which a commutator-segment leaves a commutator-brush, so as to prevent, by the diffusing or displacing action of the magnetic field thus brought to bear, any electric; arc or flash or spark at the instant of rupture of circuit between the brush and segment. * ⅜ ⅜ The magnet may be either a premanent or electro magnet. In the latter case it may be charged from any source. If used in connection with a dynamo-machine, it might'he charged by the current, or a*108 portion of the current, generated by the machine. Any desired form or construction of electro-magnet may be employed, and said magnet may be applied in any desired way, provided it be suitably arranged to bring the attractive or repulsive action of a magnetic field to bear upon any spark, arc, or electric current that may pass or tend to pass at the time of breaking or commutation, so as to diffuse or displace the same. I have herein shown a magnet for producing or bringing a magnetic field to bear; but other means for producing or bringing to bear the desired magnetic influence may be employed, — such, for instance, as a conductor forming the path of an electric current. ⅜ ⅜ * It is plain that my invention is not limited to any particular form or construction of commutator of switch.”
It will' be observed that tbe inventor’s object was to increase tbe durability of tbe conductors by preventing injury thereto. Tbe other advantages suggested by complainant’s counsel, to wit, compactness of structure, tbe safe employment of higher potentials, and other benefits, arise from tbe fact that immunity from such injury is secured, although not detailed in the letters.
The combination of claims 1 and 4 consists of a magnet or magnetic field, placed in such proximity to the contact points of an electric switch as to diffuse or displace any electric arc, spark, or flash which may pass or tend to pass at the instant of disconnecting the circuit. The vital conception is the adjustment of the magnet to the electric switch, so as to produce the desired result. Does the combination involve invention, in view of the prior state of the art? Much argument has been devoted to the meaning of the words “electric switch or commtítator.” Complainant’s counsel states that “a switch is a structure having two or more stationary terminals, and a bridging connection, which is' opened and closed at will by an operator.” At one place complainant’s expert Bentley states:
“A switch, in general, is an apparatus far controlling an electric circuit by separating or bringing into contact two electric conductors connected, respectively, to the source of electricity, whenever it is desired to manipulate the circuit, to open or to close it, or to direct it into new channels.”
At a later period in the trial the same witness stated:
“In my opening deposition, I described the switch known to the art as comprising two stationary terminals connected to the opposite branches of a circuit, and a removable bridging piece inserted between said terminals to complete the continuity of the circuit, or withdrawn therefrom to interrupt the circuit.”
It is evident that this definition is much more limited than the first. Mr. Bentley seems to contend that all known organized apparatus used for switching is within this definition. From this he appears to claim that the bridging piece is a component part of all known electrical switches. Defendant’s expert, Dr. Kennelly, defines a switch to be “any means for effecting the opening and closure of an electric circuit at will.” Prof. Wright, complainant’s expert, states that a switch “is a device for opening and closing a single circuit in some regular and systematic manner.” From the definitions of Kennelly and Wright, it would appear that the bridging piece is not necessarily a part of the switch. The letters state that the “invention is not limited to any particular form or construction of commutator or switch,” but claims 1 and 4 seem to involve the use of some portion
The conclusion is therefore reached that, if the extinction of such arcs by means of magnetism was known before the patent in suit, nothing has been added to any art by applying the knowledge to a circuit broken by a switch; the precise reason being that the switch is not exposed to or rescued from danger by reason of its being a part of a switch, but because it is a segment of an electric conductor. Therefore no economical advantage results to the switch as such, but to the conductors as such; and this was the exact event in the prior art. But the argument has proceeded upon the assumption that the prior art involved full knowledge that the magnet would extinguish an' arc of the kind under consideration, where the current was of considerable potential. It may be considered what the complainant* concedes to the prior art. Its counsel states that none of the scientists “had discovered that the burning effects upon the switch surfaces in a circuit of considerable potential could be prevented by the action of a magnet upon the arc. No one had pointed out that a destructive arc would be moved on so quickly as not to be destructive.” The complainant’s counsel further states that “some of the prior publications describe, an always ruptured circuit, over which, when current flows, it flows only by maintaining an arc, and in connection with which it was shown that either by magnetizing a part of the. circuit itself (experiments of De La Rive and of Rijke), or by bringing the magnet to the point of interruption, an arc could be deflected or extinguished." The arc was maintained, and was then deflected. *' * ■ ⅜ The most that can be said of the prior art was that it taught that an arc could, by means of a magnet, be deflected or ultimately-extinguished, and the extinguishment somewhat accelerated, as compared with conditions where no magnet was used.” The complainant would seem to differentiate the prior art from the patent in this: that the patentee showed that a magnet would not only extinguish the arc formed by a current of considerable power, but would do it so quickly as to render it harmless. If the prior art showed that a magnet would extinguish an arc, it would seem to follow that it was known that its extinguishment would stop its burning. The nature of the arc is to burn. The necessary result of the application of the magnet is to stop the burning. This nature and result existed as much before the patent as thereafter. If it -were
“A mere carrying forward or new or more extended application of tlio original thought, a change only in form, proportions, or degree, the substitution of equivalents, doing substantially the same thing in the same way by substantially the same means, with better results, is not such invention as will sustain the patent.”
The fact is that the patentee does not necessarily describe, but in practice be uses, a magnet stronger, and capable of instant extinction of the arc. This indicates increased capacity for usefulness, but nothing of invention. Ansonia Brass & Copper Co. v. Electrical Supply Co., 144 U. S. 11, 12 Sup. Ct. 601, 36 L. Ed. 327; Light Co. v. Westinghouse (C. C.) 55 Fed. 490; Id., 11 C. C. A. 342, 63 Fed. 588; Machine Co. v. Keith, 101 U. S. 479, 25 L. Ed. 939; Roberts v. Ryer, 91 U. S. 150. 23 L. Ed. 267.
Under the concession of the complainant, illustrated by the quotations from the brief above given, it is unnecessary to review the prior art. The influence of the magnet, to the extent stated, was, and for many years had been, a part of scientific knowledge. The patentee applied it to what he called an electric switch or commutator, which for the purposes of this decision has been regarded as a stated means of opening or closing an electric circuit with a segment of the conductor incorporated in the switch. Long afterwards the operation of trolley cars required the quick extinguishment of electric arcs, on a scale not before contemplated. Thereafter Prof. Thomson devised a structure which involved the use of a magnet to extinguish electric arcs. He had formerly embodied this old art in a patent, and in consequence at the later period sought to monopolize it, without any