Application of Petersen, Patent Appeal No. 6129.

• Citation: 223 F.2d 508
• Decision Date: 01 July 1955
• Docket Number: Patent Appeal No. 6129.
• Parties: Application of PETERSEN.
• Court: United States Court of Customs and Patent Appeals

223 F.2d 508 (1955)

Application of PETERSEN.

Patent Appeal No. 6129.

United States Court of Customs and Patent Appeals.

July 1, 1955.

Joshua R. H. Potts, Chicago, Ill. (Anthony J. Turchetti, Philadelphia, Pa., of counsel), for appellant.

E. L. Reynolds, Washington, D. C. (H. S. Miller, Washington, D. C., of counsel), for the Commissioner of Patents.

Before O'CONNELL, Acting Chief Judge, and JOHNSON, WORLEY, COLE, and JACKSON (retired), Judges.

COLE, Judge.

Claims 15, 16, and 18 of appellant's application for a patent are directed to a method of producing prestressed concrete structural units such as, for example, deck members for use in the construction of small bridges. The art is not new, it being well recognized that the prestressing of concrete structural units, creating stresses within the concrete itself, improves the structural characteristics of such units. By way of illustration, it is a known fact that a bridge deck member which has been subjected to prestressing during its fabrication is able to withstand a greater load than a comparable deck member which has not been prestressed.

The above numbered method claims of appellant's application allegedly define an inventive improvement over existing prestressing processes. The Primary Examiner of the United States Patent Office considered this contention, but rejected the claims as lacking in invention over a combination of prior art references. The Board of Appeals reviewed and affirmed the examiner's action, and appellant here seeks a reversal of the board's decision.

Claim 15 is representative of those on appeal. Its substance, and a sufficient explanation thereof, is contained in the following from appellant's brief on appeal:

"Prestressing has heretofore been accomplished by the use of stressing elements, such as steel rods or wires, which pass through the concrete structural unit and which are placed under tension with the ends thereof being anchored to the opposite faces of the unit externally thereof. It is evident that if the end anchorage of the wires or rods is at all impaired, the tension therein will be relieved and the beneficial effect of prestressing lost.

"The present appellant has accordingly conceived of an improved method for the manufacture of prestressed concrete structural units which overcomes any of the objections and disadvantages of present methods and which produces a greatly improved structural unit of this type. Specifically, his method consists of: (a) applying tensioning forces to the opposite ends of a multistranded helically twisted wire having helical groves therein, at the same time causing a reduction in the cross-sectional area thereof; (b) pouring concrete about said wire to cause the wire to become completely embedded in the concrete with the concrete entering said helical groves; (c) vibrating and vacuum drying the concrete to cause it to set and confine the wire with its reduced cross-sectional area; and (d) then relieving the tensioning forces from the ends of the wire.

"In this method, the multistranded helically twisted wires are susceptible to a greater reduction in cross-sectional area than ordinary reinforcing rods or wires, and provide surface irregularities in the nature of interstices, which features jointly contribute to achieving a highly efficient bond between the wires and the concrete, the concrete becoming embedded in these interstices and locked therein by the reduced wires attempting to revert to their original diametric proportions on release of the tension thereon. The step of vibration has been employed for insuring that the concrete will find its way into the most minute crevice in the multistranded reinforcing wire so as to achieve the desired bond therebetween, while the step of vacuum drying has been employed from the practical production standpoint of hastening the drying and setting of the concrete about the wires."

Appellant concedes that each of the foregoing steps of his method, taken individually, is old in the art. He relies for patentability on the combination of these old steps to contribute to the common end of producing a new, improved, and allegedly inventive prestressed concrete structural unit.

Since it may be admitted that the steps comprising appellant's method constitute a true combination, and it being well settled that a combination of old steps may be patentable if it produces, as a product of the combination, a new and useful result, the question for determination here amounts broadly to this: Is invention...