Cleveland Trust Co. v. Osher & Reiss, Inc.

• Decision Date: 26 February 1940
• Docket Number: No. 194.,194.
• Citation: 109 F.2d 917
• Parties: CLEVELAND TRUST CO. v. OSHER & REISS, Inc.
• Court: U.S. Court of Appeals — Second Circuit

109 F.2d 917 (1940)

CLEVELAND TRUST CO. v. OSHER & REISS, Inc.

No. 194.

Circuit Court of Appeals, Second Circuit.

February 26, 1940.

George L. Wilkinson and Langdon Moore, both of Chicago, Ill., and Hyland R. Johns, of New York City, for appellant.

Drury W. Cooper and Thomas J. Byrne, both of New York City, and W. P. Bair and Will Freeman, both of Chicago, Ill. (W. P. Bair, of Chicago, Ill., of counsel), for appellee.

Before L. HAND, CHASE, and CLARK, Circuit Judges.

L. HAND, Circuit Judge.

All the patents in suit are for improvements to oil-burning furnaces for heating buildings, and they all follow the same general pattern. An electric motor in the service circuit drives a pump which feeds the fuel — oil — by a pipe into the furnace. At some point, usually at the outlet of the pipe, the oil is mixed with air and discharged into the furnace in a spray. In the earlier systems a pilot light set this on fire, but in the fully developed art an electric spark was substituted. When the control room gets too cold, a thermostat closes the motor circuit and starts the motor; but, since at times the mixture does not catch fire, or goes out after it has, the pump still keeps working, for the control room remains cold, or becomes so, and the room thermostat does not open the motor circuit. To fill the furnace with the unburnt mixture is dangerous, for it is explosive and may cause serious accidents. All three of the patents in suit were for improvements upon such a system; they were designed to stop the motor when the mixture did not catch, or when it went out. More properly they were for improvements upon what the art had already done to bring about that result. We need describe only one earlier patent, which issued to Sherman & Sheppard on January 20, 1925, upon an application filed on July 8th, 1918, and which was co-pending with Scott's reissue patent, the application for the original of which was filed on April 30, 1921.

This patent disclosed an oil furnace, the motor circuit for which contained two switches: one in the "relay, J", and the "safety switch, K". The room thermostat was in a circuit in parallel with the motor circuit, which led through a magnet in the "relay, J". When the control room was cold, the thermostat closed its circuit, and the magnet moved the switch in the relay which closed the motor circuit. The pump would thereafter supply the furnace with the mixture, whether the pilot light was firing the mixture or not; and to prevent this the patentees introduced a third circuit, also in parallel with the motor circuit, which operated the "safety switch, K". In this were a second, or furnace, thermostat, "controlled by the temperature in the fire-box", (lines 63-65, page 3), and the "switch, R", open when the motor was not working. One contact of the "switch, R" was fastened to the expansible end of the "tank, Q", which a pipe connected with the blower. When the motor began to work, it pumped air into the tank, which as the pressure increased slowly expanded until it closed the "switch, R". This closed the third circuit and actuated a magnet in it, which opened the "switch, K" in the motor circuit. In this way the third circuit would always open the motor circuit, and the pump would work only intermittently. To prevent this the furnace thermostat was rigged to close when the furnace was cold, and to open when it was hot; and the "tank, Q" was designed not to close the "switch, R", before the thermostat opened. If, however, the mixture did not catch, or went out the pressure in the "tank, Q" would close the "switch, R"; and as the furnace thermostat remained closed, the "safety switch, K" broke the motor circuit.

This was an entirely operable system and was actually used, but it had two defects, or at least two disadvantages: (1) both thermostat circuits were in parallel with the service circuit, which is always at relatively high voltage; and (2) the "safety switch, K" was normally closed, and had to open to break the motor circuit. The first was bad because high voltages wear out contacts; the second is said to be dangerous because at times a switch will not open for mechanical reasons. Scott's reïssue patent remedied the first defect; his second patent, the second. The reïssue patent, itself an improvement over an earlier patent of Scott (No. 1,320,936, applied for May 9, 1919 and issued Nov. 4, 1919) disclosed the following system. When the room thermostat was open — i. e., when the control room was hot — if the "safety switch" was closed, the service current idled through the primary of a transformer set in a shunt. When the room thermostat closed, it closed a circuit passing through the secondary of this transformer, which we will call the "first thermostat circuit", and the current energized a magnet that swung a pivoted armature. In its new position this armature completed a circuit from the service wire through the motor and started it, broke the "first thermostat circuit" and completed another circuit (the "second thermostat circuit") which also passed through the secondary of the transformer. (The "second thermostat circuit" actuated the spark circuit by means of a second transformer, and so fired the furnace.) In its course it passed through a switch, one contact of which was fixed to the end of a "Bourdon tube", fed by the fuel pipe. (A "Bourdon tube" is a curved receptacle which straightens out as it fills). As soon as the motor began to work, the tube began to fill, quite as Sherman & Sheppard's pump filled the "tank, Q" with air. Its movement broke the "second thermostat circuit", but, as the tube carried one contact with it, when it had fully straightened out, it could, and did, connect the contact with another contact, and so completed a third circuit, in which were a magnet, the secondary of the original transformer, and a thermostat in the furnace. This thermostat was open when the furnace was hot, but closed when it was cold. Thus, if the mixture did not light or went out, the third circuit closed after the Bourdon tube had straightened, and actuated the magnet, which thereupon opened a switch in the motor circuit. The system was then dead until the switch was manually set again. The operation of this system presupposed that the Bourdon tube would not fully open to make contact in the third circuit until the furnace thermostat had opened its contact in that circuit.

The plaintiff urges two points of novelty in this disclosure over Sherman & Sheppard; first, that the furnace thermostat is "mounted in the combustion flue, 2", (page 2, line 34), while the thermostat in Sherman & Sheppard is on the outside of the furnace; and second, that the subsidiary circuits all derive their current from the secondary of the transformer, and are therefore at low voltage. Except for these features all the claims in suit except 21 read upon Sherman & Sheppard, and the differences in claim 21 are not patentable. The argument is that the "thermostat, P," of Sherman & Sheppard was not "directly responsive to and regulated by combustion conditions". The Eighth Circuit held the contrary in Electrol, Inc. v. Merrell & Co., 39 F.2d 873, 877, and there can be no question that it was right. We have already seen that this thermostat was "controlled by the temperature of the fire-box", not by the pilot light as the plaintiff would have us believe. In figure one it was shown as set on the outside of the furnace on the other side of the burner, D, from the pilot light. The burner mixed the air and oil and sprayed it directly into the furnace; the pilot light set it on fire just as it emerged from the tip of the burner; and it is unbelievable that, so situated it should have been expected to heat the thermostat, even if the words of the specification had not been to the contrary. Against this the plaintiff cites several passages which spoke of the thermostat as depending upon the pilot light. That was quite natural and is readily understandable, for, if the pilot light went out, the "temperature of the fire-box" would certainly fall; just as it would normally rise if it were lighted. Probably the patentees did not think of the possibility that the light, though burning, might not fire the mixture; they were right in not doing so, for it was too remote a probability; but, whatever they thought, what they said provided against just that eventuality, and nobody can follow their instructions who does not make the thermostat depend upon the temperature of the furnace. Besides, surely if it was in the wrong place, experience would cure the defect.

As to the second point, considering the short time between the filing dates of the two applications and the absence of any intervening unsuccessful efforts, we should have great doubt that it was invention merely to make the subsidiary circuits carry a low voltage; if trouble had developed from the use of the service current, the remedy would readily have suggested itself. However, we need not speculate, for the...