| 摘要 |
1,123,824. Heating resistances for packaging machines. A. SCHMERMUND. 16 Feb., 1966 [13 March, 1965], No. 10746/65. Heading H5H. [Also in Division B8] In a packaging machine in which superposed or overlapped portions of wrapping material are glued or heat sealed together, the wrapping material is heat sealed or the glue dried by contact with a heated wall or wall portion of a guide passage. The wall or wall portion is made of electrically conductive material and heated by passing current through it, slots or perforations being provided in the wall or wall portion to increase its electrical resistance. As shown, a cigarette packaging machine includes a guide passage 5, Figs. 1 and 5 (latter not shown), through which packets (23) of cigarettes are pushed by a reciprocable member (22), a pusher (25) removing them laterally as they emerge. The passage 5 comprises four walls 1-4 of which the walls 2-4 are heated and each comprise a sheet of metal backed by a heat-resistant supporting carrier 6, with an electrically insulating layer 7 separating them, the layers being connected together by electrically insulated rivets 8, or glue. The carrier 6 may be made of metal or of an electrically insulating material, e.g. ceramics or heat resistant plastics, in the latter case the insulating layer 7 may be omitted. The metal sheets 2-4 are electrically connected by metal strips 11, 12 screwed to lugs 13 of the walls. Similar lugs 14 serve as terminals for the walls 2, 4. The fourth wall 1 is mounted on levers (24), Fig. 5 (not shown), so that it may be pressed against the packets. In one embodiment, the electrical resistance of the sheets 2-4 is increased by an arrangement of slots 19, 16, see also Fig. 2 (not shown), and perforations 21, the slots extending parallel to the sides of the sheets. In a modification of this, Fig. 6 (not shown), parallel slots (119), (116) are arranged at an angle to the sides of the sheets. In a second embodiment, Fig. 8 (not shown), the carrier (206) is provided with a zig-zag groove (226) into which a continuous strip (227) of electrically conducting material is cemented. The strip (227) thus forms a wall having slots (216), (219). In another embodiment, Fig. 10 (not shown), the carrier (306) is coated e.g. galvanically with a metallic coating (327), e.g. of chromium, parallel slots (316), (319) being provided in the coating, e.g. by etching. In another embodiment, Fig. 18 (not shown), a wall (502) is provided with perforations (532), the wall being a metal sheet or a coating. In another embodiment, Figs. 12-17 (not shown), a wall is provided by a strip (427) which is bent to form parallel runs connected at the ends of the runs by bending the strip as at (430), Fig. 17 (not shown). Parallel slot-like gaps (431) are thus formed between adjacent runs of the strip. |
