| 摘要 |
<p>A tubular blank (1) of filter paper containing measured and separate quantities of tea, or a similar infusionable substance, is pleated and folded so as to obtain a bag (5) with two envelopes (6) by a method that comprises the steps of advancing blanks (1) singly and in succession along a feed direction (2) tangential to an indexing wheel (3) with radial grippers (4), taking up each blank in a position above three bearing elements (7, 8, 9) ordered along the feed direction, forming a pleat (12) in an intermediate portion (10c) of the blank, then pinching the two ends (10a, 10b) of the blank by means of movable pressure elements (16) interacting with two of the bearing elements (7, 9) so as to prevent the escape of the contents from the envelopes (6) while at the same time drawing the tubular blank (1) toward the wheel (3) to bring the two envelopes (6) together and give the filter bag (5) its final shape.</p> |
