Standard Envelope Sealer Mfg. Co. v. Graywood Mfg. Co.

ANDERSON, Circuit Judge.

After a fairly long trial, this patent infringement case has come down to a pretty narrow main issue: Are claims 10 and 11 invalid by reason of prior public use made or caused by the plaintiff itself? A minor issue as to infringement of claim 3 is also presented.

Claims 10 and 11 cover, broadly, an envelope sealer without any pressor plate, roller, or other mechanical device to press the flap against the body of the envelope after it is moistened. In lieu of such pressure, applied by various forms of mechanical devices in practically all the prior art, the plaintiff’s…