| 摘要 |
When manufacturing wooden poles, a number of sections 1 are glued together along abutting side surfaces 7, 8, so that a pipe-shaped pole 19 with a central cavity 23 is formed. The side surfaces 7, 8 which are covered with adhesive are pressed tightly against each other so that a pipe 19 is produced. Sealing lids 20, 21 or similar devices are mounted at each end of the pipe so that it is tight, after which air is pumped out of the cavity 23 through one or two of the above-mentioned lids so that a vacuum is created in space in relation to outside pressure which leads to an increase in pressure between the abutting side surfaces. The vacuum is maintained until the glued-together joints 31 have been attached. <IMAGE> |
