| 摘要 |
<p>The apparatus (1) has a bell-shaped head (2) defining a cavity (20) operatively connected to a depression source, and having an opening (22) bounded by a peripheral edge (21) tangential to a planar active surface, where the apparatus is intended to move in a direction. The peripheral edge is rectangular, where a ratio of the length and the width of the peripheral edge is between 1.5 and 4.5. A pressure unit is placed into the opening perpendicular to the direction of displacement of the apparatus.</p> |
