The opinion of the court was delivered by: LETTS
1. These suits were each brought under the provisions of Section 4915, R.S., 35 U.S.C.A. § 63, by Minnesota Mining & Manufacturing Company, plaintiff, as assignee of the patent application of John A. Brown and John Edmund Clarke, Ser. No. 171,990, filed in the United States Patent Office on October 30, 1937, and also as assignee of the patent application of the same John A. Brown and John Edmund Clarke, Ser. No. 345,538, filed July 13, 1940 (the latter application being based upon the disclosure of the earlier filed application of said John A. Brown and John Edmund Clarke), both applications being entitled Coated Granular Materials and Product Thereof, to have the Commissioner of Patents authorized to issue to plaintiff the claims set out in Paragraph 6 of the Complaint in Civil Action No. 6339 and the claims set out in Paragraph 7 of the Complaint in Civil Action No. 13,055.
2. At the trial, on motion of the plaintiff, all of the claims set out in Paragraph 6 of the Complaint in Civil Action No. 6339 were withdrawn except claim 31, which was retained; and all of the claims set out in Paragraph 7 of the Complaint in Civil Action No. 13,055 were retained, except claim 7, which was dropped. The claims retained are, therefore, claim 31 of the aforesaid Brown and Clarke application Ser. No. 171,990 and claims 1 to 6 inclusive, 8 to 10 inclusive, and 12 to 16 inclusive of the said Brown and Clarke application Ser. No. 345,538. The dropping of those claims which were dropped was to avoid duplication of claims, and this action is without prejudice to the claims retained.
3. The disclosures in the aforesaid two Brown and Clarke applications are, for the most part, substantially the same.
4. The Brown and Clarke applications in suit relate to improvements in abrasive articles, such as abrasive wheels and particularly coated abrasive articles or so-called "sandpaper", and in the improvement of the bonding characteristics of abrasive grains or grits employed in such abrasive articles.
6. The coating treatment of Brown and Clarke provides substantial improvements in the strength of bond which can be made with various adhesives. The improvements in strength of bond will vary somewhat with different adhesives or binders, and with different abrasive grits or particles, but increases in bonding strength over the teaching of Nicholson patent No. 1,910,444, and over the best prior art commercial practice, of more than 10 percent, and in many cases of the order of 20 percent and higher, are common with the Brown and Clarke invention.
7. The coated grains or grits of Brown and Clarke when used in combination with adhesives or binding agents such as glue in abrasive articles, e.g. in sandpaper, also substantially improves the ageing qualities of such abrasives and inhibits to substantial extent deterioration of the bond or adhesive.
8. Many efforts have been made prior to the Brown and Clarke invention to improve the bonding characteristics of abrasive grits, such efforts extending back for many years and being illustrated by the first four of the following patents:
Higgins et al. Patent No. 944,436 1909
Hartmann Patent No. 1,482,792 1924
Hartmann Patent No. 1,482,793 1924
Nicholson Patent No. 1,910,444 1933
Hutchins Patent No. 2,150,166 1939
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