| 摘要 |
<p>995,980. Tube-making machines. KONINKLIJKE NEDERLANDSCHE HEIDEMAATSCHAPPIJ. Oct. 8, 1963 [Oct. 8, 1962], No. 39629/63. Heading F2P. [Also in Division B3] A tube suitable for drainage and irrigation is made in apparatus which comprises a plate 3 in which is an oval hole 4, a mandrel 5 in a sleeve 6, and co-operating rollers 7, 8 with peripheral teeth 10 on the roller 7 which enter circumferential grooves 9 on the roller 8. As a strip 1 of flexible synthetic material is drawn through the apparatus it is bent to a tube with overlapping edges, by its passage through the plate 3 and sleeve 6, and the overlapping material is punched into projections 11 by the rollers 7, 8. These projections have open sides forming openings along the length of the tube for drainage or irrigation water. The roller 8 is pivoted for rotation at the end of a lever 12, on which pressure is put by a spring 14, adjustable by a screw 15 through the intermediary of a lever 16. The passage area in the wall of the tube for water may be increased by perforating the tube wall.</p> |
