| 摘要 |
<p>PURPOSE:To reduce the recovery cost of a plastic bottle and make its reuse easy by permitting the volume of the plastic bottle to be reduced when it is empty. CONSTITUTION:The body part of a plastic bottle has an expandable and contractible area consisting of a number of circumferential or spiral grooves and each groove consists of the two side parts of different lengths. Each groove has a long side part 1 and a short side part 2 interconnected in an adjoining manner and the length of the short side part comprises 30-95% of that of the long side part. The expandable and contractible area is not expanded largely by a weak force and, only when a strong compressive force is applied in the axial direction, the short side part enters the long side part to cause them to overlap and, only when a strong tensile force is applied, the overlapped part is pulled out to produce a large expansion and contraction.</p> |
