Manufacturing container or tube from paper; or other manufacturi – Container making – Pliable container
Reexamination Certificate
1997-07-02
2001-03-13
Scherbel, David A. (Department: 3723)
Manufacturing container or tube from paper; or other manufacturi
Container making
Pliable container
C053S451000, C053S551000
Reexamination Certificate
active
06200249
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus, generally referred to as a pull-down belt, for pulling a cylindrically formed bag-making material for a bag maker-packaging machine. More particularly, this invention relates to such a bag maker-packaging machine having an improved positioning mechanism for its pull-down belts.
A bag maker-packaging machine, for example, of a so-called vertical pillow type, is generally adapted to bend an elongated web of a thermoplastic flexible bag-making material (hereinafter referred to as “the film”) into a cylindrical form around a filling cylinder by means of a component known as the former, to simultaneously seal together its mutually overlapping side edge parts and to use a pair of pull-down belts to pull it further down to a transverse sealer for sealing the cylindrically formed film transversely to the direction of its motion. The filling cylinder is for the purpose of dropping articles therethrough to be packaged, and a plurality of formers with different sizes are usually made available for handling films with different widths and different ways of sealing. Most pull-down belts which have been used for this purpose are of the type which will forcefully compress the film between the belt and the filling cylinder while the film is being pulled downward. Pull-down belts of this type have the disadvantage that a roller or a slidable plate is required to be buried inside the filling cylinder, thereby narrowing the available passage for the articles dropped therethrough. With pull-down belts of this type, furthermore, it has been difficult to programmatically adjust the contact pressure.
The present inventor has disclosed, in Japanese Patent Publication Tokkai 5-4609, another type of pull-down belt adapted to pull down a film while causing it to be pulled toward the belt surface by creating a negative pressure condition. Pull-down belts of this type are able to overcome the problems of the kind described above, but they have different problems such as not being able to pull the film effectively if the gap between the belt and the film is either too large or too small because the suction force by the negative pressure may weaken, or cause a zigzag motion of the film if the gaps between the film and the pair of belts on opposite sides thereof are not equal.
SUMMARY OF THE INVENTION
It is an object of this invention to overcome all these problems of prior art pull-down belts, by providing a new apparatus capable of transporting a cylindrically formed film while pressing the film evenly and lightly such that the friction force generated thereby with the film will not be strong enough to pull it down.
It is another object of this invention to provide an improved bag maker-packaging machine capable of causing its pull-down belts to come into contact with the film every time in an optimum condition on the basis of the measured distance between specified reference positions for the belts and the surface of the film.
It is a further object of this invention to provide such an improved bag maker-packaging machine capable of causing its pull-down belts to come into contact with the film every time in an optimum condition by an effect of learning.
An apparatus embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising a pair of pull-down belts for pulling a cylindrically formed film along a filling cylinder, a pair of belt-supporting members adapted to move towards or away from each other depending on the size of the former, and elastic springs for providing each of the pull-down belts with a force which depends on the relative positions of the pull-down belts with respect to the corresponding belt-supporting members. An adjustment motor is adapted to move the pull-down belts initially to specified reference positions and therefrom towards the filling cylinder. The distance traveled by the pull-down belts from their reference positions towards the filling cylinder is monitored. The distance to be moved for each of different kinds of former is measured and stored in a memory device. Thus, whenever a particular former is selected and installed, the pull-down belts can be automatically moved to optimum positions for pulling the film down effectively by controlling the adjustment motor.
REFERENCES:
patent: 4660356 (1987-04-01), Simionato
patent: 5125217 (1992-06-01), Fukuda
patent: 5377474 (1995-01-01), Kovacs et al.
Coudert Brothers
Ishida Co. Ltd.
Ojini Anthony
Scherbel David A.
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