315 F.2d 377
Donald J. BAUER, and The Cover Board, Inc., Plaintiffs-Appellants,v.YETTER MANUFACTURING COMPANY, Inc., Defendant-Appellee.
No. 13925.
United States Court of Appeals Seventh Circuit.
March 27, 1963.

Eugene R. Johnson, Peoria, Ill., Harry A. Toulmin, Jr., Milton D. Render, Dayton, Ohio, for appellants.
Timothy L. Tilton, Chicago, Ill., Dawson, Tilton, Fallon, Lungmus & Alexander, Chicago, Ill., of counsel, for appellee.
Before HASTINGS, Chief Judge, SCHNACKENBERG and SWYGERT, Circuit Judges.
SWYGERT, Circuit Judge.


1
Plaintiff, Donald J. Bauer, patentee and owner of letters patent numbers 2,733,647 and 2,829,580, and plaintiff, The Cover Board, Inc., an Ohio corporation, licensee of Bauer, brought separate suits against defendant, Yetter Manufacturing Co., Inc., an Illinois corporation, on each patent charging infringement thereof. The suits were consolidated for trial and were tried to the court without a jury. The court found no infringement of either patent and dismissed the complaints. The District Court's decision is reported in 205 F.Supp. 904. This appeal followed.


2
It is well settled law that questions of fact are for the trial judge to determine and his findings will not be disturbed unless clearly erroneous. Armour & Co. v. Wilson & Co., 274 F.2d 143, 151, 156 (7th Cir., 1960), separate opinion of Chief Judge Hastings. Particularly when the District Court's determinations are based in part on courtroom demonstrations will this court be reluctant to upset them. Graver Tank & Mfg. Co. v. Linde Air Products Co., 336 U.S. 271, 69 S.Ct. 535, 93 L.Ed. 672 (1949).


3
We have carefully examined the briefs and the record and have considered the arguments made by counsel and are unable to hold that the factual findings or legal conclusions of the trial judge are erroneous. The trial judge properly restricted the use of the doctrine of equivalents so as not to give patent monopoly to elements or features excluded by the doctrine of file wrapper estoppel. Jacwil Mfrs. v. Batesville Casket Co., 311 F.2d 38 (7th Cir., 1962); Union Carbide & Carbon Corp. v. Graver Tank & Mfg. Co., 196 F.2d 103 (7th Cir., 1952).


4
We are in complete agreement with the opinion of the trial judge and hereby adopt it as our own. The judgment is affirmed.

