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Schriber-Schroth Co. v. Cleveland Trust Co., 305 U.S. 47 (1938)

Schriber-Schroth Co. v. Cleveland Trust Co.

No. 3

Argued October 18, 19, 1938

Decided November 7, 1938*

305 U.S. 47


1. Where it is improbable, notwithstanding the doubtful validity of a patent, that conflict of decision respecting its validity will arise in different circuits, because of the concentration in one circuit of the industry in which the patented devices are used, there is reason for granting certiorari to review a decision in that circuit sustaining it. P. 305 U. S. 50.

2. A patent does not extend beyond the invention described and explained as the statute requires; it cannot be enlarged by claims in the patent not supported by the description. P. 305 U. S. 57.

3. The application for a patent cannot be broadened by amendment so as to embrace an invention not described in the application as filed, at least when adverse rights have intervened. Powers-Kennedy Co. v. Concrete Co., 282 U. S. 175; Permutit Co. v. Graver Corporation, 284 U. S. 52. Id.

4. Amendments to Patent No. 1,815,733, to Gulick, for a combination in the structure of pistons of internal combustion engines for automobiles, designed to prevent undue thermal expansion of the pistons when in operation, were unlawfully added. P. 305 U. S. 51.

5. In this combination, the head and skirt of the piston, separated by an air space, are connected and held in proper relation to each other by two webs which extend longitudinally within the skirt and which, pierced at right angles for wrist-pin bearings, support the piston pin bosses. The skirt is longitudinally split in order to minimize the effects of thermal expansion. The Circuit Court of Appeals regarded lateral flexibility of the webs as an essential element of the invention. The original application, however, contained no reference in terms to laterally flexible webs or to the function of the webs in securing flexibility of the skirt, but described the webs as "extremely rigid," and stated that an object of the invention was "to rigidly support the piston pin bosses from

Page 305 U. S. 48

the piston walls," and that the arrangement provided "a particularly strong support for the bosses." The webs, as shown by the drawings, conformed to these specifications, and neither drawings nor specifications gave dimensions showing thickness or other proportions of the webs which might suggest a flexible structure.


(1) That, after a similar piston with the element of flexible webs had come into commercial use and another had been described in an application for patent, the patentee could not add that element to his application by amendment. P. 305 U. S. 55.

(2) Amendments to that end could not be supported as being but clarifications of the application as filed. P. 305 U. S. 57.

The contention that lateral flexibility was implied in the original description as an inherent property of the metal composing the web, and was disclosed by the drawings, is rejected.

Inherent flexibility of the web in cooperation with the slit skirt cannot be depended upon to produce the desired effect in rendering the skirt yieldable in response to cylinder wall pressure. That depends upon design of the web, with correct proportioning of the different parts as to location and thickness to produce lateral flexibility. Inherent rigidity, made more effective by design of the webs, would correspondingly curtail the desired effect.

6. Decisions of the Court of Appeals for the District of Columbia and the Court of Customs and Patent Appeals sustaining the Gulick amendments are accorded weight, but are not controlling in this Court when the validity of the amendments is involved in an infringement case. P. 305 U. S. 59.

7. As flexible webs are neither described in the specifications nor mentioned in the claims of the patent for a like combination to Maynard, No. 1,655,968, they can be imported into them only by reference to the drawings or by inference from the inherent flexibility of the structure, which, as in the case of Gulick, are insufficient to accomplish the result. P. 305 U. S. 60.

92 F.2d 330 reversed.

Certiorari, 304 U.S. 587, to review the reversal of a decree holding certain patent claims invalid in suits for infringement. Other patents, held invalid by the District Court but not passed upon by the court below, were not involved in this review.

Page 305 U. S. 49

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