Blaw-Knox Company v. ID LAIN COMPANY, 11591.

• Decision Date: 27 February 1956
• Docket Number: No. 11591.,11591.
• Citation: 108 USPQ 356,230 F.2d 373
• Parties: BLAW-KNOX COMPANY, Plaintiff-Appellant, v. I. D. LAIN COMPANY (Inc.), Defendant-Appellee.
• Court: U.S. Court of Appeals — Seventh Circuit

108 USPQ 356, 230 F.2d 373 (1956)

BLAW-KNOX COMPANY, Plaintiff-Appellant, v. I. D. LAIN COMPANY (Inc.), Defendant-Appellee.

No. 11591.

United States Court of Appeals Seventh Circuit.

February 27, 1956.

Walter J. Blenko, Pittsburgh, Pa., Paul W. Gordon, Springfield, Ill., William H. Parmelee, Pittsburgh, Pa., William Henry Venable, Pittsburgh, Pa., of counsel, for appellant.

Otis A. Earl, Kalamazoo, Mich., Arthur M. Fitzgerald, Springfield, Ill., Austin A. Webb, Kalamazoo, Mich., of counsel, for appellee.

Before DUFFY, Chief Judge, and LINDLEY and SWAIM, Circuit Judges.

LINDLEY, Circuit Judge.

Plaintiff appeals from a judgment declaring invalid all claims of its patent to Bushnell, its assignor, number 2,361,377, applied for September 23, 1941, allowed October 31, 1944, on which it had brought suit against defendant for infringement. The Court found, further, that if the patent were valid, it would be infringed by the device used by defendant. There is no attack upon the latter finding, but plaintiff, on appeal, questions the judgment of invalidity.

The patent pertains to a mechanism for paving concrete highways and other roadways and to the methods employed in operating it. Claim 2, typical and representative of all claims covering the apparatus, is as follows: "In a concrete paving machine comprising (1) a car movable along the area to be paved, (2) a strike-off blade on the car (a) extending transversely thereof and lying in a vertical plane (3) means for adjustably mounting the blade in fixed relation on the car, (a) said blade having a narrow bottom working edge, which, through its engagement with the paving material leaves a surface which is fissured and porous, (4) and an element on the car in spaced relation to the scraper and substantially parallel therewith and which is behind the scraper relative to the operating direction of the car (a) for vibrating the paving material and by such vibration close the fissures and the portions from the bottom toward the top, (b) said element also having a smooth surface to wipe over the paving material and seal the surface thereof."

Claim 8, typical and representative of the method claims, reads: "The method of paving which comprises (1) dragging a strike-off having a narrow edge over a surface on which paving material has been spread (a) to remove excess paving material (b) and to produce a fissured and porous surface on the paving material (2) and thereafter subjecting the fissured and porous area of the paving material to a vibrating and smoothing action (a) at a distance back of the strike-off (b) greater than the depth of the paving material but sufficiently close to the strike-off so that the crevices will be closed and sealed before there has been any substantial evaporation of water or setting of the concrete."

When the demand for labor-saving devices for extensive paving of concrete highways arose, various delvers in the art of road-building machinery were not slow to offer suggestions. Thus, many devices were publicized. The conventional contrivance generally adopted consisted of a power driven machine which progresses on the highway as the concrete is dumped in front of it. This machine usually included, first, near its front, a spreader, which leveled or spread out relatively evenly the raw concrete placed on the foundation of the highway in front of the power driven machine. Closely following the spreader was an element known variously as the scraper or cut-off, which further leveled and evened the concrete. Scrapers were of various forms, varying from so-called snub-nosed cut-offs to relatively thin pieces of metal, that of the patentee being described as comparatively narrow. The scraper, following the spreader, left a rather rough surface on the concrete. In practice the paving apparatus was followed by a finishing machine which put in final shape the slab of concrete constituting the highway. There is no controversy between the parties that the combinations mentioned were conventional and old.

However, as the art developed, road builders and engineers drawing specifications for roads soon learned that a thin watery concrete, though it flowed more easily and was, therefore, more readily adaptable to the levelling off process, would not result in as strong a roadway as would use of a heavier concrete, that is, one containing less water, which did not flow so freely. Consequently, the industry found it essential that the heavier concrete be employed in order to meet engineering specifications for highways designed to resist constant wear from the traffic to which they were subjected. Though they recognized this essential principle, builders encountered difficulty in meeting specifications calling for the heavier concrete, for the reason that the latter material does not flow as freely, as we have said, and does not pack so perfectly, as does the lighter, more watery mixture. Consequently, it was found that air cells in the concrete tended to honeycomb the mixture after it was placed in the road, contributing to the early disintegration of the roadway when in use.

To correct this was a vital necessity, the seriousness of which seems to have been universally recognized. Various delvers in the art offered their respective ideas. Among...