Automatic Appliance Co. v. McNiece Motor Co.

20 F.2d 578, 1927 U.S. App. LEXIS 2592
CourtCourt of Appeals for the Eighth Circuit
DecidedJune 9, 1927
DocketNo. 7623
StatusPublished
Cited by9 cases

This text of 20 F.2d 578 (Automatic Appliance Co. v. McNiece Motor Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Eighth Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Automatic Appliance Co. v. McNiece Motor Co., 20 F.2d 578, 1927 U.S. App. LEXIS 2592 (8th Cir. 1927).

Opinion

BOOTH, Circuit Judge.

This is a suit for alleged infringement by appellee (hereafter called defendant) of patent No. 1,-345,870, granted to Robert Nash and George Henry Alexander on July 6, 1920. In the trial court decree went for defendant, on the ground of noninfringement. Validity of plaintiff’s patent was not adjudicated.

The complaint is in conventional form, alleging ownership of the patent, infringement thereof by the defendant, and praying for an injunction and an accounting. The answer denies infringement, and sets up invalidity of the patent by reason of certain prior patents alleged to be anticipations, also by reason of lack of patentable novelty in view of the pri- or art.

Plaintiff’s Patent and Its Scope.

The patent is for a “fluid pressure measuring instrument,” and the specifications state that the parties have invented certain new and useful improvements relating thereto. Such instruments are old in the art. They find wide application at the present time in indicating the depth or quantity of gasoline in the tank of an automobile, and the devices of both plaintiff and defendant are used for that purpose — the indicator of the device being placed on the dash of the automobile.

The specifications of the patent in suit recite:

“In its rudimentary form such apparatus when employed, for example, for indicating the level of fluid in a tank, consists of a vessel (herein termed a displacement chamber) containing entrapped air or other gas, said vessel being in communication at its lower end with the lower end of the tank, and at its upper end with one end of a U-tube containing the indicating liquid. When the air in the tank is under pressure, the other end of the U-tube is connected to the air space in the tank, otherwise it is open to the atmosphere.”

Figure 1 of the drawings is here reproduced :

Fig. I, Patent in 5u>t with Descriptive Letteíuhú,

[580]*580The underlying .principle of such devices in general is that the pressure exerted by a body of liquid upon a body of air entrapped in a bell-or displacement chamber varies in direct proportion to the depth to which the bell is immersed in the liquid. A' change of the depth will be reflected in a change of pressure. Referring to the figure, it is apparent that when the tank a is filled with gasoline, some of it will pass through the pipe c into the displacement chamber b; and rising therein, will entrap a volume of air. The pressure of the gasoline in the tank being communicated to the entrapped air will be further communicated through the pipe g to the liquid in the U-tube or gauge, depressing the liquid in the left leg, and causing it to rise in the right.

The gauge being so constructed as to indicate the difference in the levels of the gasoline in the itank and the gasoline in the displacement chamber, it' is apparent that the real depth in the gasoline tank can be ascertained correctly from time to time by this method, only if the level in the displacement chamber remains constant. The level of the gasoline in the displacement chamber is called the “datum level,” and, unless this datum level is constant, the reading on the gauge will necessarily be incorrect. The constancy of this datum level depends upon the uniformity of the volume of entrapped air in the displacement chamber. The object of the invention of the patent in suit, is to enable a practically constant datum level to be maintained, and to be conveniently restored, when occasion requires, in a simple and convenient manner. The action of plaintiff’s device is thus described in the specifications:

“To compensate for absorption or leakage of air from the displacement chamber air can be blown in through the pipe e periodically and restore the original datum level. Or air can be blown into the chamber through a cock i. Excess air then escapes through the pipe e. The latter thus serves both in determining and in restoring the datum level. It is also to be noted that the inner open end of the pipe e is'flush with the normal datum level of the chamber b so that in case the level falls below normal it will be automatically returned to or constantly maintained normal by liquid flowing into the chamber from the tank a while, if the datum level rises above normal, air may be blown into the pipe e to restore the original datum level.”

The patent has but one claim. It reads as follows:

“In fluid pressure measuring instruments, the combination comprising a closed displacement chamber in communication with a body of fluid and containing a quantity of entrapped air, the height of the air space above the fluid datum level in the chamber being small relatively to the diameter of the chamber, a fluid gauge communicating at the end with the air space in the displacement chamber, and a pipe in communication with the fluid in said chamber,, said pipe serving to determine the datum level and also as a passage for air to .or from the chamber for restoring such level when required, substantially as described.”

The elements of the claim are:

(1) A closed displacement chamber (b) in communication with a body of fluid (a) and containing a quantity of entrapped air, the height of the air space above the fluid datum level in the chamber being small relatively to the diameter of the chamber;

(2) A fluid gauge (h) communicating at one end with the air space in the displacement chamber; and

(3) A pipe (e) in communication with the fluid in said chamber, said pipe serving to determine the datum level and also as a passage for air to or from the chamber for re-restoring such level when required, substantially as described.

This claim being a combination claim, and no one of the elements thereof being claimed as an invention, all of such elements are conclusively presumed either to be old in the art or not patentable. Richards v. Chase Elevator Co., 159 U. S. 477, 486, 16 S. Ct. 53, 40 L. Ed. 225; Hay v. Heath Cycle Co. (C. C. A.) 71 F. 411, 413; Campbell v. Conde Implement Co. (C. C.) 74 F. 745; Johnson Automobile Lock Co. v. Noser, etc., Co., 9 F. (2d) 265 (C. C. A. 8). It follows as a matter of law that the contention of plaintiff that the vent pipe e in his patent is not found in the prior art, and is a patentable addition to the combination, cannot be sustained'; nor is it true as a matter of fact that the vent tube or its equivalent is not f ound in the prior art. Such tube is found in the Murphy patent, 867,994; the equivalent is found in the Ereneh patent to Remy, 453,970, which has a three-way cock; the tube is also found in the Payne patent (British), 14,811, and in Parks, 1,131,412 — although in these various patents the arrangement of the tube and the functions which it performs are not the same as in plaintiff’s patent. Plaintiff’s contribution, if any, to the prior art, was in the particular arrangement of the old elements and in the proportionate size thereof; for example, the first element has the displacement chamber so constructed that “the height of the air space above the fluid datum level in the [581]*581chamber [is] small relatively to the diameter of the chamber,” and in the third element the vent pipe e

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Bluebook (online)
20 F.2d 578, 1927 U.S. App. LEXIS 2592, Counsel Stack Legal Research, https://law.counselstack.com/opinion/automatic-appliance-co-v-mcniece-motor-co-ca8-1927.