Electric Cable Joint Co. v. Brooklyn Edison Co.

Citations: 292 U.S. 69; 54 S. Ct. 586; 78 L. Ed. 1131; 1934 U.S. LEXIS 698Docket: 611

Court: Supreme Court of the United States; April 2, 1934; Federal Supreme Court; Federal Appellate Court

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Certiorari was granted to review a Second Circuit Court of Appeals decree that invalidated the Torchio patent (No. 1,172,322) for an "improvement in protective devices for electric cable joints," citing a lack of invention. The District Court's decision conflicted with a prior Sixth Circuit ruling, which had upheld the patent's validity in a related case. The patent addresses issues of current leakage at high-tension electric cable joints, which consist of multiple copper conductors insulated and surrounded by a lead sheath. Leakage occurs due to imperfect insulation, often exacerbated by the deterioration of insulating materials from heat, dehydration, or damage during installation. The patent's key claim outlines a device meant to enhance insulation at cable joints, featuring a pervious insulating material, an impervious sleeve, and a receptacle for an insulating fluid that permeates the insulating body, effectively preventing current leakage.

On February 11, 1927, a disclaimer was filed by an assignee of the patent, excluding all improvements except for specific electric cables and an insulating liquid. Petitioner's expert testified that Torchio was not the first to identify oil as an insulating material, nor the first to create cables with conductors enclosed in oil-permeated insulation, joints, or larger sleeves hermetically sealed to metal sheaths. The only novel elements in Torchio's claim were a receptacle communicating with the sleeve's interior and the insulating oil. The main legal question is whether these additions constitute an inventive step. The earlier Sixth Circuit decision upheld claims 3 and 4, noting that Torchio’s substitution of a liquid insulating compound for a non-flowing one was inventive enough to constitute patentability, despite not addressing the reservoir's impact. However, both lower courts in the current case found that prior art disclosed the use of oil within sleeves and determined that the addition of the reservoir did not involve invention, as it was known before Torchio. The prior art included British patent Geipel, which indicated the use of oil and other materials as insulation in cable joints, and Lemp patent, which described oil used in electric transformers with insulating materials allowing for fluid intake.

In 1907, De Gelder documented Amsterdam's electric cable system, detailing high tension cables operating at 3,000 volts, which featured paper insulation soaked in a thin, oily, resin-like liquid. Cable joints were wrapped in linen tape saturated with oil and encased in a soldered lead sleeve. The insulation process involved pouring a hot insulating mass, similar to the impregnating oil, into the joint. De Gelder noted that British firms used a thinner resinous oil for their high-tension cables.

Since 1911, the Consolidated Gas Electric Light and Power Company in Baltimore has employed oil for insulating cables carrying 13,000 volts or more. These cables consist of three paper-wrapped conductors insulated with oil-soaked jute and encased in a lead sheath. To prevent oil drainage and insulation failure in vertical sections, cables were connected to enlarged containers (potheads) that replenished the jute insulation. Initially, paraffin was used in the potheads but was replaced by a fluid oil to prevent drying out and ensure effective insulation.

Vernier, in a 1911 article, analyzed the insulation of joints in high-tension cables up to 20,000 volts. He emphasized the hazards posed by voids in insulating materials that could lead to gas ionization and reduced dielectric strength. Vernier described a cable design similar to De Gelder’s, with oil-impregnated tape and an insulating compound filling the lead sleeve. He advocated for a viscous compound that remains fluid at ordinary temperatures to penetrate all crevices without forming air voids, a principle echoed in Pender's 1914 American Handbook of Electrical Engineers.

In 1914, Torchio reported on the Berlin cable system, describing its cables with 30,000 volts as having joints enclosed in lead sleeves, soldered with 'wiped joints,' and insulated with a semi-liquid compound. An associate’s report from August 1914 on the Boston underground cable system, carrying 13,000 to 25,000 volts, detailed cables with three conductors, wrapped in paper and sheathed in lead, and a joint box filled with an insulating compound of molasses-like viscosity. The prior art demonstrates that the insulating fluid referenced in Torchio's fourth claim was not novel and had been documented previously, with recognized advantages over non-fluid compounds. Therefore, the patentability of Torchio’s invention relies on the incorporation of additional elements from claim 4, specifically a receptacle containing the fluid that communicates with the sleeve. This combination is claimed to enhance joint insulation and compensate for insulating oil loss due to temperature-induced expansion and contraction of the cable, which leads to potential voids. The reservoir ensures an adequate supply of fluid oil to address these losses and maintain insulation integrity.

Breathing, defined as the expansion and contraction of cable materials due to temperature changes, is recognized as a natural phenomenon within common scientific knowledge, and was noted prior to Torchio's work. Historical publications, such as De Gelder's 1907 recommendations, highlighted the effects of heat on cables, including the potential for insulating fluid to flow out and water to be drawn in when cooling occurs. Observations from the Baltimore light and power system illustrated oil migration in cables and the overflow of oil reservoirs when heated. Vernier also documented the shrinkage of insulating compounds and the necessity for oil to fill joint sleeves, emphasizing that viscosity was crucial for effective insulation.

Torchio's patent claims the use of free-flowing oil in cable joints, a concept recognized in prior art for its adaptability to the temperature fluctuations of cables. While Torchio introduced an oil reservoir to the joint combination, the mere addition of this element does not constitute invention unless it results from innovative insights rather than standard practices. The patent illustrates different configurations for the oil reservoir, including one that increases interior oil space without a separate chamber, similar to Vernier's earlier sketches. Although Vernier did not label this design as a reservoir, its purpose aligns with the oil-holding function described in Torchio's claims.

The prior art indicated the potential for enlarging a receptacle or reservoir, exemplified by the potheads utilized by the Baltimore Power and Light Company for oil impregnation in cable insulation. Lemp presented a design with an additional holding space for oil insulation in transformers. However, increasing the oil space in an existing combination was deemed a task requiring no special skill or inventive step. The integration of a familiar device, such as a connecting oil cup or reservoir, to enhance the oil supply did not constitute invention, reflecting the ordinary skills of practitioners in the field. Precedents from several cases, including Concrete Appliances Co. v. Gomery and Saranac Automatic Machine Corporation v. Wirebounds Patents Co., supported the notion that neither the methods nor the outcomes were novel. Consequently, claim 4 was deemed invalid, and the previous decree was affirmed.