| 摘要 |
1277672 Seaming non-metallic sheet material HESSER MASCHINENFABRIK-AG 16 March 1970 [15 March 1969] 12452/70 Heading B5K [Also in Division H5] A tool for heat sealing thermoplastic films comprises a heater bar 1, preferably of aluminium, a low-voltage heating tape 2 for heating the bar 1, a heat-insulated holder 5 which surrounds the bar 1 and the tape 2, and prestressed resilient material 7 disposed in the holder 5 and evenly pressing the tape 2 against the surface 9 of the bar 1 opposite the working surface 8 and which has an electrical-insulating coating 10 thereon over the.whole length of the bar 1. The holder 5 comprises clamping plates 3 between which is disposed a fixing bar 4 attachable to a packaging machine. Preferably, the pressure strips 7 are made of silicone rubber, and the coating 10 is a thin strip of polyimide or polytetrafluoroethylene or an oxide layer. For higher working temperatures, asbestos, ceramic material or polytetrafluoroethylene may be inserted between the tape 2 and the strips 7. Insulating elements 6 of silicone rubber, polytetrafluoroethylene or asbestos are provided on both sides of the bar 1. The surface 8 may be covered with silicone rubber or polytetrafluoroethylene. Bolts 11 surrounded by heat-insulating bushings 12 hold the bar 1, the plates 3, the elements 6 and the bar 4 together. The temperature of the bar 1 can be precisely controlled by a feeler (15), Figs. 1 and 3 (both not shown). The heat-sealing tool may be used with an identical counter-tool or an unheated cheekplate. |
