| 摘要 |
904,326. Seaming non-metallic sheet material. PNEUMATIC SCALE CORPORATION Ltd. March 18, 1960 [Nov. 16, 1959], No. 9696/60. Class 42 (1). [Also in Group XVII] Apparatus for closing and sealing the open end of a thermoplastic tube comprises means for engaging and flattening opposed walls of a tube, means for pressing the walls and heating them by conduction to soften and fuse the walls to form a seal and means for thereafter engaging and pressing the softened walls to set and shape the seal whilst it is cooling. As shown, filled tubes 10 are supported in pockets 12 on tray 14 positioned on platform 16 so that the ends of the tubes are between elongated gripping jaws 24, 26, which are supported on and movable with an elevating unit 28 operated by piston-rod 57. Operation of unit 28 withdraws the tubes 10 from pockets 12 and presents their upper ends to heat-sealing mechanism 25 whereupon the empty tray 14 is retracted and filled with another bank of tubes. The jaws 24, 26 are operated by a two-armed lever on rocking shaft 78 operated by air cylinder 90. The heatsealing mechanism 25 includes a pair of elongated, rigid heat-sealing and pressure-applying jaws 120, 122 on rocker arms 124, 126 mounted on shafts 130, 132 operated from air cylinder 140, each heat-sealing jaw being provided with electric heating elements 128. The heat and pressure can be regulated to suit different thermoplastic tube material. After sealing, the jaws 120, 122 are retracted and a pair of shaping jaws 160, 162, preferably at room temperature, are brought into engagement with the flattened tube while it is still in a softened or semisoftened state. Shaping jaws 160, 162 are carried on arms 164, 166 clamped on rocker shafts 168, 170 operated by air cylinder 172. The air cylinders are controlled for timing the operations thereof by a plurality of cam-operated valves. The fused area of the seal is defined by the shaped portions of the jaws 160, 162 and is at least equal in thickness to the thickness of the wall of the container. |
