Dayton Engineering Laboratories Co. v. Kent

264 F. 103, 1920 U.S. App. LEXIS 1241
Court of Appeals for the Third Circuit·Decided March 18, 1920·No. No. 2509·Published

Opinion

HAIGHT, Circuit Judge.

In the court below the Dayton Engineering Laboratories Company, owner of patent No. 1,223,180, granted to Charles F. Kettering, on April 17, 1917, for an ignition system, charged A. Atwater Kent, the appellee, with infringement of claims 4. 5, 7, and 8 thereof. On final hearing, after an opinion reported in [104] 260 Fed. 187, the bill was dismissed. Thereupon the plaintiff took this appeal.

In vi.ew of the full discussion in the opinion of the learned judge of the court below of the intended uses, construction, and mode of operation of the apparatus of the patent and that which it is claimed infringes it, we deem it unnecessary to describe either with any particularity. Broadly stated, the invention of the patent resides in the use, in the main circuit of an ignition system, of a thermal resistance which will readily permit the normal flow of electrical current through the circuit, but upon an abnormal flow will reduce and cut down the current. As a result, it is claimed, the patented device will perform two separate and distinct functions, viz.: (1) The reduction of current to prevent the depletion of a storage battery when the engine is not running, or, as it is expressed in the case, is on or at “a dwell”; (2) the regulation of the flow of current for high and low speeds, respectively, or, in other words, the furnishing of a variable current for variable speeds: Each of these functions are so different, so far as 'the applicability of the facts of this case is concerned, that they should be considered separately. We accordingly do so, and in the order in which they are before stated.

[1] 1. One of the main defects in certain of the ignition systems of the prior art was that when the engine was not running — when it was on or at a dwell — and the current was, through carelessness or otherwise, not cut off, the current would continue to flow through the circuit and deplete the storage battery, thus wasting and materially reducing the limited supply of current stored therein. Accordingly, the main purpose which Kettering sought to accomplish, and the particular advantage claimed for his invention, is that it will reduce the flow of current during dwells, as expressed in the specifications, to “substantially a negligible quantity.”

[2] While, of course, it cannot be stated with mathematical exactitude what a “negligible quantity” is, there is no real difficulty in ascertaining, for the purposes of this case, what is meant by that expression, when the object of the patent is considered in connection with the statement in the specifications of the defects in the prior art. As to the ignition systems of the prior art, the patentee says that, when the circuit remains closed, they permit—

“a continuous flow of current to pass therethrough and a consequent partial or complete depletion of tile source of electrical energy.”

He then states that the object of his invention is to provide a means to—

“readily permit the normal flow of current therethrough, but which, upon an abnormal or continuous flow of current from the electrical source, will act to reduce and cut down the amount of current flowing through the circuit, to substantially a negligible quantity, and thus conserve the supply of current, even though the main circuit is closed, * * * for. an extended length of time.”

Again:

“If this flow [a continuous flow] of current is permitted to exist, as is generally the case, in ignition systems now in use, the supply of current con-[105] tainpfl in the battery or accumulator 20, would be materially reduced within a short time.”

It is therefore clear that a “negligible quantity” is something materially less than that which will result in a complete or a material partial depletion of the battery within a comparatively short time. While no claim, in terms, so limits the function of the patented, apparatus, yet such a limitation must be clearly read into the claims, unless we are to disregard the patentee’s own statement of what differentiates 'his apparatus from those of the prior art. The thermal resistance in the main or primary circuit of the defendant’s alleged infringing apparatus is used only in connection with an ignition system having a generator operated by the engine, and its purpose is not to reduce the current in the sense of the patent, but merely to prevent the overheating of its primary induction coil. Indeed, for engines which do not have such a generator, the defendant furnishes, or at least recommends the use of, another device which is so constructed that, when the engine is on a dwell, there can be no flow of current whatever.

[3] Of course, as a thermal resistance was a well-known device of the art, the defendant has a right to use it for any other purpose than that of the patent, provided that he does not also in effect accomplish the same result or perform the same function as that claimed for the patented apparatus; especially since the extent of the resistance which it will effect, and the consequent reduction of the current which it will produce, is dependent upon the length and size of the wire used in the resistance coil. It is therefore manifest that unless the alleged infringing apparatus reduces the current, on dwells, to “substantially a negligible quantity,” as that expression is above construed, it does not infringe. As found by the court below, the evidence shows that, when it was used during a test made on plaintiff’s behalf, a given supply of current lasted for 39 hours and IS minutes, and that, when the same apparatus was used without the thermal resistance, the same supply of current lasted 31 hours and 25 minutes. Likewise, the evidence on behalf of the defendant is that the final or stable current upon a dwell when the alleged infringing device is used is from 60 to 64 per cent, of its value at the inception of the dwell, and this notwithstanding that one-quarter of such reduction is effected by the rise in temperaturue and consequent resistance in the primary induction coil. The evidence, therefore, does not demonstrate, we think, that the alleged infringing apparatus reduces the flow of current on dwells to “substantially a negligible quantity,” as hereinbefore defined. It accordingly follows that no infringement of the patent has been shown, so far as its function in respect to dwells is concerned.

Free access — add to your briefcase to read the full text and ask questions with AI

Dayton Engineering Laboratories Co. v. Kent, 264 F. 103, 1920 U.S. App. LEXIS 1241 (3d Cir. 1920).

264 F. 103 (Dayton Engineering Laboratories Co. v. Kent) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.

Related

Dayton Engineering Laboratories Co. v. Kent
260 F. 187 (E.D. Pennsylvania, 1919)