| 摘要 |
340,393. Making tubes. MEYERKELLER ET CIE, AKT.-GES., O., 45, Kellerstrasse, Lucerne, Switzerland. Dec. 4, 1929, No. 37177. Convention date, Jan. 18. [Classes 83 (ii) and 83 (iv).] Corrugating.-A corrugated tube is formed from a plain tube by first pressing the corrugations from the inside by means of a ram of yielding material such as rubber or by a pressure fluid ram and subsequently transforming the intermediate cylindrical parts of the tube into the troughs of the corrugations by rolling. The tube 1 is held in a two part matrix 2 corrugated internally and the corrugations are pressed up by a rubber ram 3 actuated by a ram 4 with a projection 6 guided in a recess in the pressure abutment member 5. The matrix 2 has at least two corrugations, one of which takes a corrugation already formed in the tube to serve as spacing means for the next corrugation to be formed. The cylindrical portions between the partly formed corrugations are then shaped by rolls 7, 8, Fig. 5 and the corrugations closed in by rolls 7a, 8a, Fig. 6. |
