| 摘要 |
<p>The device enables an envelope to be opened without a paper knife or other instrument. It consists of a cutting element solidly fixed to the envelope e.g. by adhesive. This cutter can be of any resistant material which will cut the envelope e.g. wire, metal strip, or stiff textile. The weakened part of the envelope is obtained by perforation, grooving, or reducing the thickness of the material. All types of envelopes can carry the device.</p> |
