Package making – With cover-adjunct application or formation – Adjunct comprising provision to allow access to contents,...
Reexamination Certificate
2001-11-01
2004-03-30
Gerrity, Stephen F. (Department: 3721)
Package making
With cover-adjunct application or formation
Adjunct comprising provision to allow access to contents,...
C053S139200, C053S550000
Reexamination Certificate
active
06711875
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a form-fill-seal machine, particularly a form-fill-seal machine wherein a web of bag material, such as foil, before transforming it into a tubular shape, is provided with so-called zipper strips, one for each bag to be made/filled. Said zipper strips generally consist of two strip members situated opposite each other and provided with male and female parts that can be brought into detachable engagement with each other, are taken from a stock and are applied transverse to the web, either with or without a limited pre-weld or pre-adhesion. In the action of transverse sealing the bags, the zipper strip is also permanently welded to the bag walls.
BRIEF DESCRIPTION OF THE INVENTION
From U.S. Pat. No. 4,617,683 it is known to apply a zipper strip provided with adjacent male and female parts, over the full width of a web of bag material, by engaging a leading area with a vacuum head and moving the head transverse over the upper side of the web to the other edge. Subsequently the zipper strip is welded to the web by means of a thermal seal rod extending from above and an anvil. Alternatively the zipper strip may be provided with a heat activated glue.
From U.S. Pat. No. 4,878,987 it is known to supply the cooperating male and female parts of the zipper strip from both sides, transverse to the web, by means of pusher rolls. The male and female strips are then each pushed from their side towards the center, guided by transverse ducts, and then welded to the web.
From the international patent application WO 98/03328 it is known to place a zipper strip transverse to the web of bag material by means of a vacuum band positioned above the web and weld the strip to the bag material.
Applying the zipper strips requires a high control of the orientation and the exact location of the strips, as imperfections in it may hinder the further process and may result in malfunctioning.
OBJECT OF THE INVENTION
It is an object of the invention to provide a form-fill-seal machine of the type mentioned in the preamble with which a very high degree of control can be achieved in placing the zipper strips.
It is a further object of the invention to provide a form-fill-seal machine of the type mentioned in the preamble, with which a high processing speed can be realized of high accuracy.
SUMMARY OF THE INVENTION
From one aspect the invention to that end provides a form-fill-seal machine comprising means for moving a web of packaging material through the machine according to a process path and means for transforming the web into filled bags, furthermore comprising a zipper strip applicator device having means for supplying a zipper strip for each bag transverse to the process path, which supply means comprise a first and a second conveyor, which in the supply direction of the zipper strip are placed one behind the other and are both provided with means for retaining or engaging the zipper strip during supply, a cutting means such as a blade being placed between the first and the second conveyor for cutting the zipper strip and the first and the second conveyor being provided with their own first and second drive means.
The division into two conveyors makes it possible to divide functions as well, and namely a supply function for the first conveyor and a positioning function for the second conveyor, the zipper strip each time being held over his length by the first and/or second conveyor.
Preferably the machine is provided with control means for the first and second drive means and the blade, the control means being adjusted to consecutively operate the first drive means to transfer a predetermined length of zipper strip to the second conveyor, to subsequently operate the blade and then operate the second conveyor for positioning the cut-off zipper strip portion transverse to the web.
Preferably the control means are adjusted to let both conveyors move at the same speed during the supply of the length of zipper strip.
It is preferred here that the retaining means of the first and the second conveyors as well are controlled by the control means, preferably for continuously activating them. They may be designed as vacuum band means—known per se—. In view of efficiency of the suction and creating as few as possible process disrupting air flows, it is advantageous when the machine is provided with means for adjusting the active length of the vacuum means for the second conveyor. Preferably the control means are then provided with means for comparing an entered zipper strip length and the position in transverse direction to the web and the adjusted length of the vacuum means, and of means for releasing the drive of the machine based on the outcome of said comparison. When the length of the vacuum means does not correspond to the one necessary for the process in question the machine will not be released.
The means for adjusting the active length of the vacuum means preferably comprise a tube to be connected to a vacuum source, which tube in its circumference is provided with series of apertures of different length extending in tube direction, and which is rotatable in an adjustable manner to let a selected series of apertures form the connection between the apertures in the vacuum band and the tube.
It is further preferred that at least the second conveyor is placed below the web. This improves the stability of the zipper strip.
The controllability of the zipper strip is further improved when the machine is furthermore provided with means for guiding the zipper strip on the first and/or second conveyor, which guiding means are preferably formed by a rigid guiding strip, which is positioned to extend between the male and female parts of the zipper strip. In this way the zipper strip is guided in sideward direction, so that it is prevented that it would want to run off from the conveyors as a result of its natural inclination to warp in the main plane.
Preferably the guiding strip is interrupted, and it is particularly formed by a series of teeth, so that frictional forces, that may counteract a smooth supply of the zipper strip, are limited to a minimum. The guidance is improved when the teeth have inclined side edges and/or rounded tips.
As a result of the interrupted guidance, in particular the teeth, the negative effects of the undulation in the zipper strip, which undulation is the result of the rolled-up position in which the zipper strip material is supplied, is further reduced, because of reduction of the friction and the guidance in the vertical plane. As a result the grip of the retaining means, particularly the vacuum means is improved.
Preferably the guiding strip is positioned to—considered in process path-engage the upstream side of the zipper strip, between the strip members having the male and female parts.
In a further development the zipper strip applicator device is also provided with an anvil strip for use in the pre-sealing of the zipper strip to the web, which anvil strip then is preferably situated at the—considered in process path—downstream side of the second conveyor. The applicator device here also provides a counter force during the pre-sealing.
In a further development the zipper strip applicator device is supported on an auxiliary frame, which itself is supported in a main frame of the machine, the auxiliary frame with respect to the main frame being moveable between a retracted operative position and an extended adjustment position. The initial insertion of the zipper strip can then take place in an easily accessible manner. It is preferred here that a calibration is provided on the second conveyor, extending along the retaining means, preferably starting at the location of the blade.
When the machine is further provided with control means that have been provided with means for noticing the operative position of the auxiliary frame and with means for releasing the drive of the machine based on that observation, it is ensured that only in case of a correct position of the auxiliary frame and thus of the applicator device the machine can start
Daal Peter Hubertus
Hendriks Peter Joseph
Tax Wilhelmus Catharina Gerardus Maria
Van Rens Joseph Johan Maria
Aquarius B.V.
Desai Hemant M
Gerrity Stephen F.
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