| 摘要 |
<p>A package making machine of the vertical form, fill and seal type has a tube former for receiving flexible packaging material in thin flat strip form and for juxtaposing opposite side edges thereof in parallel vertically extending relationship to provide a depending tube open at the top. Side and end sealers respectively seal the vertical edge portions and provide vertically spaced horizontally extending end seals across the tube. A product dispenser associated with the former discharges measured quantities of product to the tube interior space through its open upper end, a bottom seal having first been provided across the tube by the end sealer. An improved tube advancing or feed means occupies a minimum space vertically beneath the former and provides for a short product drop. The feed means comprises a pair of vacuum feed rolls on spaced horizontal axes and in parallel relationship to peripherally engage opposite sides of the tube. Back-up members inside the tube provide for firm tube and roll engagement over a substantial portion of the roll peripheral surface and for efficient tube feeding operation. Alternatively, four vacuum feed rolls are provided in a rectangular configuration for four sided tube engagement. The vacuum rolls may have associated stationary distributors for sequentially providing a vacuum and venting the vacuum passageways and openings therein. Alternatively, vacuum boxes may be provided for hollow feed rolls with the rolls projecting partially through sealed openings to engage the tube.</p> |
