| 摘要 |
1,016,649. Seaming non-metallic sheet material; punching apparatus. HUYCK CORPORATION. May 21, 1964 [May 24, 1963], No. 21127/64. Headings B4B, B5K and B5N. [Also in Division F4] In a method of producing a belt for the drying section of a paper-making or similar machine, a sheet of substantially incompressible fdlymeric material such as polyethylene terephthalate is perforated to provide a series of spaced perforations substantially entirely throughout, preferably with uninterrupted paths extending longitudinally of the belt, and joining the end portions of the sheet to form a belt movable in an endless path. A layer of compressible material, e.g. open-cell foam or a bat of fibrous material, may be laminated to the belt. Punching apparatus.-The perforations are formed, after sheets of the material have been sealed in side-by-side relationship, by a punching apparatus, Fig. 3 (not shown), comprising a series of cylindrical, downwardly-extending punches which are movable in directions perpendicular to the plane of the sheet or sheets. The lower surfaces of the punches are recessed to form sharp cutting edges and are at a temperature below the softening point of the material. The perforations are from 0À01 to 0À25 inch in diameter and the number of perforations from 10 to 6000 per square inch. Seaming.-The ends of the webs are joined by ultra-sonic welding apparatus 70, Fig. 7, including a sine wave voltage source 71 connected to a transducer 72 arranged to impart vibratory mechanical motion at a fixed ultrasonic frequency to a welding element or horn 72a. The ends of the belt 60 may be formed with a 45 degree bevel 78 and may be moved along a table 75 beneath the horn, or the belt may remain stationary and the welding apparatus may be moved relative thereto. In another embodiment the sheet is adhesively interconnected or is joined by lamination, e.g. by a polyester tape. In the embodiment of Figs. 8 and 9 (not shown), the ends of the belts are folded back upon themselves, held in place by stitching and the folds are notched to provide integrally formed loops which are interleaved and an elongated rod is inserted through the loops to form the endless belt construction. In the embodiment of Figs. 10 and 11 (not shown), the end portions of the web have transversely extending webs stitched thereto with clipper hooks sewn thereto to replace the loops of the prior embodiment. Laminating.-A drier belt is formed of a non-woven batt of natural or synthetic fibres which may be pre-formed, e.g. by needling, felting, chemical bonding which batt is laminated to a sheet of polyester film. The fibres forming the batt may be given a predetermined orientation by electrostatic deposition on the sheet, and the batt is secured as by a polyurethane resin adhesive to the sheet. In Fig. 5 (not shown), a layer of open cell plastic foam e.g. polyurethane resin, is laminated to a sheet of perforated polyester film by a suitable adhesive. |
