| 摘要 |
812,783. Applying transparent patches to windowed envelopes. WINKLER, R., and DUNNEBIER, K. Jan. 28, 1957 [April 28, 1956], No. 2931/57. Class 73 A web 1 of transparent patch material is fed by a feed roller 4 via a reversing roller 3 to a cutting device 5, 7 which cuts the web only partially, e.g. by perforations, and the web then passes between pull-and-brake rollers 10, 11 which tension the web and advances it between a suction roller 12 and a co-operating pressure roller 13. The suction roller 12 rotates faster than the travelling speed of the web imposed by the rollers 10, 11 and consequently tears its leading perforated section off the web while the next section still remains clamped between the rollers 10, 11. The detached patch then passes between roller 12 and a suction roller 14 together with an envelope blank 16 for application to its window. Since the patch is not detached until immediately prior to its application to the envelope, tension in the web is maintained. |
