| 摘要 |
<p>A mailing envelope has a front (1), a back flap (4) joined at a bottom fold line (5) to the front, side flaps (6) inwardly folded and secured to the back flap, and a top flap (3). So that the envelope is suitable for use in a very wide range of mailing machines:- (a) the respective side edges (8) of the top flap (3) extend at 65 - 75 DEG to the top fold line for a perpendicular distance of at least 5 mm from the top fold line, (b) the side flaps (6) have top shoulders (10) which each extend away from the side fold line (7) at 10 - 20 DEG to the top fold line (2) for a perpendicular distance of at least 18 mm, (c) the throat depth is at least 20 mm for a distance of at least 35 mm on each side of the centre of the top fold line (2), and (d) said top shoulders (10) intersect the upper edge (11-13) of the back flap (4) at a perpendicular distance in the range 4 - 15 mm from the top fold (2), and at this intersection (14) (i) the upper edge (13) of the back flap is at +/- 10 DEG to the top fold line (2), and (ii) the radius of curvature of the upper edge (13) is not less than 20 mm. 4</p> |
