| 摘要 |
The vacuum cleaner dust bag is made of filter paper with a cardboard reinforcement plate (3) provided for the surface associated with the air intake pipe of the cleaner and is provided in the peripheral area of the opening with a seal which is formed by a foil (13) of plastics of low elasticity and high ductility which covers the plate (3). This seal can be readily manufactured since it can be applied to the prefabricated reinforcement plates on normal lining machines after which the opening in the foil is merely punched out. A continuous production of the plates is possible by punching out the openings in an endless moving web of cardboard and then applying a layer of glue. Openings are similarly punched out of a continuous endless web of foil following which the foil web and cardboard web are placed together and glued with matching openings whereupon the reinforcement plates are stamped out. |
