The present invention relates generally to container-forming systems and methods. In especially preferred embodiments, the present invention relates to gas-fired burner systems and methods which serve to seal seams of paperboard containers during manufacture.
It is often necessary to apply localized heat in a very precise manner to heat portions of articles during the manufacture thereof. For example, some containers are made from paperboard having a polymeric coating therein (i.e., so-called polycoated paperboard). During manufacture of containers from such polycoated paperboard, therefore, it is necessary for localized regions thereof to be heated rapidly and accurately in order to form high quality, leak-proof seams. Heating of the paperboard serves to soften the polymeric coating thereon to such an extent that when cooled the overlapped regions of the paperboard will be bonded one to another in a leak-proof manner.
Various techniques are known generally in the art for the purpose of localized heating of polycoated paperboard during the manufacture of containers therefrom. For example, according to one prior art technique, compressed air is heated either electrically or by means of a gas-fired heater. The heated air is then routed to the localized regions of the polycoated paperboard by means of suitable ducting. (See in this regard, U.S. Pat. No. 6,022,213, the entire content of which is incorporated hereinto expressly by reference.)
More recently, in U.S. Pat. No. 6,139,481 to Norwood et al (the entire content of which is incorporated hereinto expressly by reference), there is disclosed a gas-fired heater which serves to heat localized regions of polycoated paperboard directly. Direct localized heating of the polycoated board has a significant cost advantage over the indirect heating (e.g., using heated compressed air) techniques of the prior art. However, as larger containers are attempted to be manufactured, there exists a real nontrivial problem to ensure that the entire bottom wall seam is adequately heated and thus sealed sufficiently to prevent leakage.
It would therefore be highly desirable if gas-fired heaters could be provided for the direct localized heating of relatively large-sized polycoated paperboard containers during manufacture. It is therefore towards fulfilling such a need that the present invention is directed.
Broadly, the present invention is embodied in systems and methods for making a paperboard container wherein lateral side and the arcuate bottom edge regions of a paperboard sidewall blank may be heated simultaneously. In especially preferred embodiments, a sidewall blank heater assembly is provided having upper and lower sidewall blank heaters for simultaneously heating upper and lower edge strips of the sidewall blank adjacent lateral edges thereof, and a bottom sidewall seam heater for heating a generally curved strip adjacent an arcuate bottom edge of the sidewall blank simultaneously with the upper and lower edge strips. The sidewall blank is thereafter curved about a forming mandrel at a container-forming station so as to overlap the heated upper and lower edge strips of the sidewall blank to form a longitudinal container side seam, while the bottom edge of the sidewall blank is brought into contact with a paperboard bottom wall blank to form an annular container bottom seam. A bottom seam heater assembly is most preferably provided for circumferentially heating the container bottom seam simultaneously while the sidewall blank is curved about the forming mandrel at the container-forming station. In such a manner, high quality, leak proof seams of the paperboard container ensue.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.
Reference will hereinafter be made to the accompanying drawings, wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;
Accompanying
As is well known, the sidewall blanks SB are punched from a sheet of paperboard PB being fed from a paperboard feedstock roll (not shown). The sidewall blanks SB are thus sequentially grabbed by transfer fingers 20 associated with the sidewall feed turret subsystem SS2. The feed turret subsystem SS2 thus rotates in the direction of arrow A1 so as to present each of the sidewall blanks SB sequentially to the container-forming station CS3 which, in the state of the system 10 depicted in
The sidewall feed turret subsystem SS2 presents the sidewall blanks SB to upper and lower side seam heater assemblies 30, 50, respectively, and a bottom sidewall seam heater assembly 70. The side seam heater assemblies 20, 30 serve to heat localized upper and lower strip regions of the polymeric coating on the sidewall blanks SB adjacent their respective lateral edges, respectively. Thus, when subsequently indexed to the container forming station CS3 (occupied by mandrel M1 in the state of the system 10 depicted in FIG. 1), these heated upper and lower strip regions will be juxtaposed one on top of the other so that when the polymeric coating cools, a high quality leak-proof side seam CS on the resulting container C discharged from the container discharge station CS6.
The bottom seam heater assembly 70 supplies heat along a generally arcuate region adjacent the curved bottom edge of the side wall blank SB. Heating of such arcuate region adjacent the curved bottom edge of the side wall blank will thus facilitate the joining of the bottom wall blank (not shown) to the side wall blank SB at the container forming station CS3. In addition, the bottom wall seam associated with the bottom wall blank is heated simultaneously with the sidewall formation at container forming station CS3 by means of the bottom wall seam heater assembly 90.
As is conventional, a bottom wall blank (not shown) is punched via bottom wall blank former BBF from a sheet of bottom wall paperboard feedstock PBB fed from a roll thereof (not shown) and positioned at the end of mandrel M5 which, in the state of the system 10 depicted in
The upper side seam heater 30 is shown in an enlarged manner in accompanying
In a similar manner, the lower side seam heater 50 is provided so as to heat a strip of polymeric coating on a lower surface of the sidewall blank SB facing the apertured tubular heater bar 52 thereof. Thus, as shown in the accompanying FIGURES, the surfaces of the sidewall blank facing each of the upper and lower side seam heaters 30, 50 will ultimately become the inner and outer surfaces of the container C. The heater bar 52 of the lower side seam heater 50 is thus supported in close proximity to the left side seam of the sidewall blank SB by means of support post 54, and support arms 56, 58. A flame sensor 60 is provided and is electrically interconnected to the gas manifold assembly GMA so as to terminate supply of combustible gas to the heater bar in the event that no flame is detected.
One end of the heater bar 72 associated with the bottom sidewall seam heater 70 is nested within a recess 32-1 of the heater bar 32 associated with the upper side seam heater 30 (see FIG. 3). As shown in
Collectively, therefore the heaters 30, 50 and 70 serve to heat simultaneously regions of the sidewall blank prior to formation of the container C so that when formed, high quality leak proof seams are provided. Following such simultaneous heating of the sidewall blank SB by means of the heaters 30, 50 and 70, the sidewall feed turret subsystem SS2 will then be indexed so as to present the heated sidewall blank SB to the container forming station CS3. As briefly described above in reference to
The bottom wall seam heater assembly 90 includes a generally hollow heater disc 92 having flame apertures formed in its circumferential side wall. The heater disc 92 is supported at the forward end of a supply conduit 94 which is connected operatively to the gas supply manifold assembly GSA which serves to supply a combustible gas to the interior of the disc 92. An igniter 96 is provided to ignite the gas within the disc 92 so that flames from such combustion extend radially outwardly of the disc 92 through its sidewall apertures.
The gas supply conduit 94 is supported and carried by an L-shaped bracket 100 attached to the forward end of an actuator rod 102 assocaited with air-operated cylinder 104 housed within the body 106 of the heater assembly 90. The bracket 100 is also attached to the forward ends of guide rods 108-1, 108-2 which are mounted for reciprocal sliding movements through the body 106. The rear ends of the rods 108-1, 108-2 are connected rigidly to a bridge plate 110 which carries a support post 112 for the compression spring 114. As shown in
The bracket 100, and hence the heater disc 92, is therefore capable of being reciprocally moved between retracted and advanced positions as shown in solid and phantom lines, respectively in FIG. 10. Thus, the heater disc 92 is adapted to being reciprocally moved a distance (arrow A3 in
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
3111063 | Herman | Nov 1963 | A |
3249024 | Shiu | May 1966 | A |
3364825 | Baumgartner | Jan 1968 | A |
3439590 | Crafton et al. | Apr 1969 | A |
3475243 | Scalora | Oct 1969 | A |
3648573 | LeFebvre et al. | Mar 1972 | A |
3713952 | Schafer et al | Jan 1973 | A |
3977306 | Flynn | Aug 1976 | A |
4074619 | Feliks | Feb 1978 | A |
4147494 | Ando et al. | Apr 1979 | A |
4405299 | Serber | Sep 1983 | A |
4409045 | Busse | Oct 1983 | A |
4490130 | Konzal et al. | Dec 1984 | A |
5195885 | Medina | Mar 1993 | A |
5655899 | Hura et al. | Aug 1997 | A |
5992489 | Busse | Nov 1999 | A |
6022213 | Harthun | Feb 2000 | A |
6139481 | Norwood et al. | Oct 2000 | A |
Number | Date | Country |
---|---|---|
3-247914 | Nov 1991 | JP |
Number | Date | Country | |
---|---|---|---|
20040224829 A1 | Nov 2004 | US |