Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – With bending – folding – winding – or wrapping means
Reissue Patent
1996-12-04
2001-02-06
Engel, James (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
With bending, folding, winding, or wrapping means
C156S446000, C156S578000, C118S416000
Reissue Patent
active
RE037039
ABSTRACT:
The invention refers to an apparatus for glueing the tail or outer end of a web material wound to form a roll or log. It includes means for unwinding the tail of the web of the material from a log; means for applying glue to the log; means for re-winding the tail on to the log and glueing it thereto; and means for transferring said log.
BACKGROUND OF THE INVENTION
A winding apparatus of this general type is described in U.S. Pat. No. 4,475,974. That apparatus comprises chain means which support pairs of bearing rollers. The logs to be glued are disposed on these bearing rollers. Each roll or log is transported by means of a conveyor member through a first station in which the tail or outer end of the web is unwound from the log and laid down onto a flat surface. At a second station a nozzle, moving parallel to the axis of the log, applies glue to the end of the unwound material. At a third station, the log is rotated between the two bearing rollers so as to wrap the outer end and back onto the log and thus glue it to the outer surface of the log. Located downstream of these stations are log-pressing and closing rollers and a discharge surface. This apparatus makes it possible to attain high outputs per hour in that, at each instant, three logs are processed at the same time in the three stations for the unwinding, glueing and closing of the log, respectively. However, this type of glue applicator has a rather complex and costly structure.
It is an object of the invention to provide an apparatus of the above-mentioned type which makes it possible to reach high outputs per hour with an extremely simple construction and with a limited number of movable parts.
DESCRIPTION OF THE INVENTION
In the apparatus of the present invention, the means for applying the glue includes a dispenser device having means forming an upwardly oriented slit from which the glue is delivered by overflowing. The log transferring means discharges said log, with the tail unwound therefrom, causing it to roll over the slit while said tail is unwrapped from the log. Said slit may be of any shape. Moreover, a plurality of adjacent slits may also be provided.
In a particularly advantageous embodiment, the slit extends in a direction substantially parallel to the log axis at least for a portion of the length of the log.
With such arrangement when the log is discharged, it rolls across a guide surface and, during rolling, it passes over the slit from which the glue is continuously (or discontinuously) supplied, so that, at a predetermined location of the log surface, a strip of glue having a pattern the same as the dispensing slit is applied thereon. As the log continues to roll, the tail is automatically rewound over the log and pressed against the log where the glue has been applied. The glueing occurs therefore extremely swiftly and without the need for dispensing nozzles moving longitudinally along the log, as in prior machines. In fact, by the simple rolling of the log over the slit, the glue is applied along the entire length of the log. Gravity, which causes the rolling of the log, causes the subsequent re-wrapping of the tail.
To transfer the log from the tail-unwinding station to the glue-application station, a flexible conveyor may be provided, which includes a bearing means on which the log is supported. The bearing means may be made to oscillate to discharge the log at a predetermined position onto an inclined table which has an opening aligned with the slit of the glue dispenser device. In practice, the conveyor member may be a pair of parallel chains between which one or more cradles are disposed, pendulum-like, and pivoted to the said conveyor.
Along the path of the conveyor, a guide means is also provided to cause the cradle to oscillate about the axis on which the latter is pivoted to the conveyor, thereby causing the discharge of the log when the cradle passes a pre-determined point along the same guide means. In this way, no separate pusher is necessary to discharge the log from the conveyor because it is the motion of the conveyor which causes the oscillation of the cradle and thus the discharge of the log.
In a particularly advantageous embodiment, the glue-dispensing device may comprise a container, especially a tubular container, extending transversely to the movement of the log within the apparatus, said container being provided with means defining the glue-dispensing slit and further connected to means for the supply of the glue. Disposed under the tubular container is a tank for collecting the glue which overflows from the said slit. A conduit is provided in the bottom of the tank for recovering the excess glue.
Advantageously, said container may be connected to a glue reservoir in which the glue level is maintained above the height of the dispensing slit. In this way, a continuous flow of glue from the reservoir to the container, and from the latter to the dispensing slit, is obtained. The glue flow rate is determined by the difference in height between the glue surface within the reservoir and the dispenser slit by the pressure loss along the glue path, by the glue viscosity, and by the slit dimensions.
This type of supply has the advantage of not requiring a controlled dispensing means, such as a pump and a nozzle and, moreover, it allows a continuous and easily adjustable flow of glue from the reservoir to the slit, while the excess of glue overflowing from the slit, which is not picked up by the logs rolling over the same slit, is collected in the underlying tank from which it can be easily recovered and made to flow back into the upper reservoir. This avoids the drawbacks exhibited by the nozzle-type dispensing means which, when the apparatus is stopped even for short periods, are clogged up by the drying of the glue, thus making it difficult to re-start the apparatus. With a continuous flow of glue, as obtained through the dispenser of the present invention, there is no undesirable drying of glue during short pauses of the apparatus, since the supply is not interrupted and the glue remains in circulation.
In a distinctively advantageous embodiment of the invention, the means for unwinding the tail of the log consist of a pair of cylinders rotating about fixed axes and combined with a suction box having a surface on which the unwound tail is made to rest. Contrary to the apparatus of known type, therefore, only one unwinding station is provided in this case which station remains in a fixed position with respect to the machine frame while the log, with the tail already unwound, is picked up from the said station by the above-described conveyor.
The invention also refers to a method for glueing the tail of a log formed of web material onto the log itself, wherein: the glue is applied on an area of the web material which is still wound up on the log (and not on the unwound tail), by making said log roll with its tail being unwound, over the glue-dispensing slit.
The invention further refers to a glue dispenser, mostly for use in an apparatus for glueing the tail of logs or rolls of web material, comprising a tubular container provided with means defining a slit from which the glue is dispensed, and means for feeding the glue to said tubular container. A storage tank may be provided below the container to collect the glue overflowing from said slit. Advantageously the storage tank may be connected to a glue reservoir into which the glue collected by said tank is re-admitted to let it into the tubular container afterwards. Said reservoir may be located at such a height that the difference between the level of glue inside the reservoir and the height of the dispenser slit will allow the glue to flow through the latter.
DETAILED DESCRIPTION
The invention will be better understood by following the description and the attached drawing, which shows a feasible, not limiting, embodiment of the same invention. In the drawing:
FIG. 1
shows an ensemble side view of the apparatus according to the invention.
FIG. 2
is an enlarged detail of the tail unwinding region.
FIG. 3
shows an enlarged sid
Breiner & Breiner
Engel James
Fabio Perini S.p.A.
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