| 摘要 |
837,586. Seaming. UNION CARBIDE CORPORATION. April 2, 1958 [April 3, 1957], No. 10541/58. Class 42 (1). A method of sealing edges of a stack of three or more sheets of thermoplastic material to form a large sheet comprises folding the longitudinal edge 18 of one sheet 10 and seaming it to the edge of a sheet 12, placing the longitudinal edge of another sheet 14 adjacent to the edge of the sheet 12, folding one of the longitudinal edges of either the sheet 12 or 14 and forming a seam 19. Any number of sheets may thus be secured and, as shown in Fig. 3, the outer sheets 10, 11 may be joined by a seam 43 to form a tube. Fig. 1 shows a machine for joining four sheets 10, 12, 14, 16. The sheets 10, 14 pass over rollers E, G, respectively, which form a right-angle fold in the sheets. Roller F also folds the sheet 12 at the opposite side. Sheets 10, 14 pass through guides 22, 24 which complete the folds in the sheets 10, 14, a similar guide being provided on the opposite side for the sheet 12. The sheets then pass to solvent or adhesive spreaders 26, 28 and then to rollers 30, 32 for sealing. The rollers 30, 32 may be carried by shoes and spaced apart to co-operate with further rollers formed as electrodes for high-frequency heating. |
