| 摘要 |
A method and apparatus for making a tubular sleeve of thermo-plastic material wherein a strip of sheet stock 15 is fed to a rotatable turret 11 having a plurality of drivable rotatable mandrels 12 thereon. The strip is severed by a knife 19 into individual rectangular blanks, each having a leading edge and a trailing edge, and each blank is formed into a cylindrical shaped sleeve wrapped around a mandrel 12 with the trailing edge overlapping the exterior of the leading edge of the blank, hot gas being applied by a blower F to both surfaces of the trailing edge. The mandrels are moved past a sealing station S and a plurality of seal bars 21 are rotated so they move successively in an arcuate path generally tangentially to the path of the blank to bring the sealing surface of each bar into engagement with the overlapped edges and apply radial pressure thereto to fuse the edges together and form a seam. Each bar 21 has an arcuate concave contacting surface and is formed with radially extending portions 31 a, 31 b, Fig. 5, of stepped configuration to apply a greater pressure to one part of the seam than the other. A solvent spray may be fed through the blower F or separately. <IMAGE> |
