General Electric Co. v. Minneapolis-Honeywell R. Co., 161.

• Decision Date: 17 March 1941
• Docket Number: No. 161.,161.
• Citation: 118 F.2d 278
• Parties: GENERAL ELECTRIC CO. v. MINNEAPOLIS-HONEYWELL REGULATOR CO.
• Court: U.S. Court of Appeals — Second Circuit

118 F.2d 278 (1941)

GENERAL ELECTRIC CO. v. MINNEAPOLIS-HONEYWELL REGULATOR CO.

No. 161.

Circuit Court of Appeals, Second Circuit.

March 17, 1941.

Harrison F. Lyman and William R. Woodward, both of Boston, Mass., and Alexander C. Neave, of New York City, for plaintiff.

Drury W. Cooper, of New York City, W. P. Bair and Will Freeman, both of Chicago, Ill., and George H. Fisher, of Minneapolis, Minn., for defendant-appellant.

Before SWAN, CHASE, and CLARK, Circuit Judges.

CHASE, Circuit Judge.

The plaintiff is the owner of United States Patent No. 1,583,496 which was granted May 4, 1926, on the application of William L. Shafer filed Feb. 23, 1924. The suit is the usual one in equity alleging that two thermostats made and sold by the defendant infringe claims 1, 2, 3, 5, 8, 9, 10 and 14-20, inclusive. Nothing turns upon the particular language of any claim and it is sufficient to state that they cover a heat-regulating system designed to control the rate of combustion in a furnace used to heat houses whether the fuel be solid, liquid or a gas and are primarily directed to the thermostat used in the system. For present purposes other parts of the heating system may be ignored. All the claims were held valid and infringed in the decree from which the defendant has appealed.

The problem Shafer solved was created by two conditions inherent in such a heating system regulated by a thermostat. When a furnace is operated for a time under forced draft or its equivalent it will continue to supply a comparatively large amount of heat after the temperature at which the thermostat has been set has been attained. This continuation of heat will cause that temperature to continue to go up and overheat the room or house. This is called in the record "overshooting". Perhaps a seemingly obvious way to correct overshooting would be to set the thermostat so as to leave only a short range of variation between the upper and lower temperatures but that is not feasible because the contact points of the thermostat must always be placed far enough apart so that the current at one will not affect the other to prevent the firm setting that will do away with what is called "hovering" that causes sparks.

The thermostat of the patent uses the well-known principle that a bimetallic strip made of metals having different co-efficients of expansion will warp when heated. Shafer perceived that that warping, which opened and closed the electrical circuit controlled by the thermostat, when brought about only by the temperature in the space to be heated took place too slowly to open the circuit and cut down the rate of combustion in the furnace before too much actual or potential heat could cause overshooting. His remedy for that, and it was a good one, was to increase the warping speed of the strip and thus get the effect of a closer setting of the contacts in the thermostat without, however, setting them closely enough to cause hovering. His way to make the bimetallic strip in the thermostat warp faster was to heat it faster by adding heat at a point near enough to it so that its action was affected both by the temperature of the space to be heated by the furnace and by the additional heat. And the method for so doing disclosed in his specifications was to install a small electric light near the bimetallic strip and connect it in the thermostat's circuit so that when the contacts closed to bring about an increased combustion rate in the furnace the electric light would go on and burn until the strip so influenced by its heat would warp to shut off the forced draft before the temperature in the space to be heated had actually been raised to the degree at which the thermostat had been set. The furnace, of course, would continue to supply heat until it cooled but as part or all of such heat would be needed to bring the room temperature up to the actual thermostatic setting there would be less overshooting and conceivably none. Shafer disclosed as an alternative source of added heat a resistance coil instead of an electric light and that is clearly an equivalent means.

After Shafer had made and installed such a device in his own home, he made another for a friend who used that in his home. Such use antedated Shafer's application for his patent by more than two years and a part of the defense is that these uses were public and make the patent invalid under Sec. 31 of Title 35 U.S.C.A. Such uses did make it incumbent upon the plaintiff to prove that they were experimental only for otherwise they would be within what the statute makes unpatentable. A. Schrader's Sons v. Wein Corp., Inc., 2 Cir., 9 F.2d 306. But whether the uses were public or experimental was a question of fact. There was adequate evidence to show that Shafer was actually experimenting with and changing his device up to a time within two years of the date when his application for a patent was filed. Consequently the trial court was justified in finding, as it did, that there was no public use by Shafer or others more than two years prior to his application. The experimental use would not invalidate the patent. Elizabeth v. American Nich. Pavement Co., 97 U.S. 126, 24 L.Ed. 1000.

Several patents were introduced to prove that the claims were invalid for anticipation. Of these No. 1,403,963 granted to Klingel Jan. 17, 1922 on his application filed...