Folding and packaging machine

Abstract

Abstract An automatic machine and method of operation for erecting a flat blank to form a completely folded container. The machine has a blank feed mechanism that stores flat blanks and transfers individual blanks using pressure-aided means to an infeed opening in the machine. A pressure-assisted receiver vertically movable within the machine ascends to engage the blank present at the in-feed opening and then draws the blank, including any articles to be packaged loaded during a pause at the infeed opening, downwardly into the machine past a series of folding members to partially erect the blank into a tray-like container. The container is now advanced in a horizontal direction along guide means and past another arrangement of folding members to further fold the blank to form a semi-erected container. An elevator positioned to receive the processed blank from the guide means raises the semi-erected container into a compression chamber to complete final folding operations. Discharge means eject the completed container through an output opening in the machine. To form a sealed container, pressure-supplied glue applicators are positioned at an acute angle adjacent the guide means so as to apply glue to all blank surfaces requiring glue during the horizontal traversal of the partially-erected container along the guide means. During a first activity, pressure is supplied to the applicators so that glue at a first volume per unit length is applied to the side flaps. During a second activity, the pressure is increased so that the volume of glue per unit length applied to the front panel is substantially the same as the first volume. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates, generally, to automatic packaging machines and, more particularly, to the types that sequentially fold a paperboard blank about a quantity of articles and subsequently glue the erected blank to form a sealed container that encloses the articles. 2. Description of the Prior Art U.S. Pat. No. 3,531,914 issued to M. G. Franklin on Oct. 6, 1970 and U.S. Pat. No. 3,665,675 issued to R. H. Johnson on May 30, 1972 are both representative of prior art packaging machines that commence operation with a flat, one-piece paperboard blank. To elucidate some shortcomings of these prior art packaging machines, an overview description of both structure and operation of the conventional machines is now provided. A typical cycle of operation of a prior art packaging machine begins with the machine operator manually positioning the flat paperboard blank over a machine input opening which is aligned with a vertically movable in-feed mechanism. The articles to be encased are then manually loaded on the section of the blank which ultimately forms the bottom of the sealed container. The automatic portion of the cycle is now activated and downward movement of the vertically movable mechanism draws both the blank and the articles into the machine. If the total weight of the articles does not suffice to hold the blank in-place during drawdown, additional holding force is provided by vacuum acting through suction devices formed as part of the movable mechanism. During descent, the blank engages a plurality of folding members and when the mechanism reaches its lowest position, front and back panels as well as two side flaps, all part of the blank, are perpendicular to the bottom panel of the blank and entrap minor flaps of the blank, thereby forming a tray containing the articles. The semi-erected container with articles is now removed from the vertical mechanism and moved along the first leg of a horizontal, generally L-shaped path, during which movement glue is applied to the outer surfaces of the two side flaps. The glue is applied to one side flap from a glue application station comprising at least one glue positioned along the path of lateral movement of the side flap. Also, a similarly designed and arranged glue station simultaneously applies glue to the other side flap. As movement along this leg continues, a cover panel, interconnected with the blank, is folded into a horizontal position and two top flaps, both associated with the cover panel, are folded downwardly to contact the glue on the side flaps. The partially folded container is now reoriented by directing the blank along the second leg of the L-shaped path, whereupon glue from a separate applicator station, distinct from the previous glue applicator stations, is applied to the outer surface of the front panel. Continued movement of the container along the second leg causes the sealing flap, secured to the cover panel, to be folded downwardly to contact the adhesive on the front panel. Also, during traverse of the second leg, the previously glued sides of the container engage abutments that firmly hold the sides in-place so the glue may properly set. The completely sealed container is now either directly ejected from the machine through a discharge port if the glue is fully set, or is transferred to a compression chamber for glue curing. In the latter case, after a prescribed time interval, the container is then ejected from the chamber through the discharge port. In the aforementioned overview description, one evident shortcoming of a typical prior art packaging machine is the inordinate number of manual tasks that must be completed by the machine operator before activation of the automatic phase of the operation. Besides placing the articles on the blank, the operator has the additional responsibility of correctly positioning the blank at the in-feed port. Thus, because of the exertions effected by one-at-a-time feeding of the blanks, the accuracy of the blank placement and, indeed, the speed of the overall packaging operation, is dependent upon the manual dexterity and stamina of the machine attendant. A fast, accurate blank feed step would benefit both packaging quality and production efficiency. Other shortcomings of a conventional machine can be explained by focusing on the L-shaped path design. In this L-shaped arrangement, two distinct orientations involving two separate movements of the blank are employed to apply glue to the three surfaces requiring adhesive, namely, the two side flaps and the front panel. Therefore, this design necessitates a minimum of three glue application stations, including two oppositely directed stations arranged on the first leg of the path to spread glue separately but synchronously on each side flap, and a third station on the second leg that applies glue to the front panel. Also, this design usually means that each leg of the path has similar or even duplicate members, such as rails to guide the blank and mechanisms to move the blank along the rails. The shortcomings that arise with the prior art packaging machines of the type described may be observed by comparison of the L-shaped design with the inventive subject matter of this instant application. It is to be demonstrated hereinafter that a sealed container can be formed in a machine using only one glue-applying movement of the blank and wherein no blank reorientations are necessary and glue is applied to all three of the surfaces requiring glue from only two glue applicator stations. Hence, in view of the subject matter of this application, additional shortcomings of the prior art designs include reduced reliability, increased maintenance, higher cost and large floor space requirements, all of which are primarily due to duplication of both structure and operations. SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an efficient, reliable and versatile automatic packaging machine and method of operation that minimize manual interactions and offer structural improvement and production benefits to encourage and induce widespread use. Another object of this invention is to provide an automatic packaging machine and method of operation which utilize a pressure-aided automatic blank feed mechanism to yield accurate, effortless and speedy blank access and placement. It is a further object of this invention to provide an automatic packaging machine and method of operation requiring only one basic movement of the blank to accomplish all required glue application operations without reorientation of the blank during this movement. Yet another object of this invention is to provide an automatic packaging machine of substantially reduced size yet is easily adjustable so as to accommodate various container sizes to increase machine versatility and cost effectiveness. These and other objects are realized in accordance with the present invention of an improved packaging machine and method of operation which subject the blank to fewer distinct movements and orientations to effect gluing and which minimize manual interactions. The device in accordance with the present invention generally comprises the following five interrelated and mutually dependent means traversed seriatim: (a) a pressure-aided blank feed mechanism that stores numerous blanks and, automatically during each machine cycle, removes a single blank from storage and accurately positions the blank over the machine in-feed opening; (b) a pressure-assisted vertical erection mechanism that, firstly, operates in conjunction with the blank feed mechanism to receive and then retain the blank appearing at the in-feed opening and, secondly, draws the blank, along with the previously manually or automatically loaded articles to be packaged, downwardly into the machine in order to partially erect the container about the articles; (c) a glue application mechanism, including symmetrically located, angularly positioned, pressure-supplied glue applicators, that receives and then laterally moves the semi-erected container past the applicators and initiates final folding operations. During the lateral movement, a first gluing activity causes adhesive to be applied to the side flaps by the glue applicators supplied with a first pressure and, as lateral movement continues, a second gluing activity causes adhesive to be applied to the front panel by the glue applicators, supplied with a second pressure at least as great as the first pressure; (d) a compression mechanism that receives and then houses the nearly completed container to await curing of the glue; and (e) a discharge mechanism for subsequent and suitable ejection of the sealed container from the machine. More specific descriptions of the five interdependent means of the preferred embodiment are now provided. In the preferred embodiment, it is helpful to visualize the machine divided into two separately identifiable ensembles, namely: (i) a rectangularly-shaped base housing and (ii) the blank feed mechanism. The base housing contains the erection mechanism, glue application mechanism, compression mechanism and discharge mechanism. Furthermore, the erection, glue application and compression mechanisms cause movements of the blank to take place in a single plane along a vertically oriented U-shaped path. The base housing has an in-feed opening on its top, near the front, and an output opening on its back wall. The blank feed mechanism is mounted on the top of the base housing, near the back, and has members constructed and arranged to cooperate with the mechanisms interior to the base housing. In the preferred embodiment, the blank feed mechanism includes a storage magazine, a platen and a pivot arm mechanism. A quantity of blanks is stacked up-right in the magazine, which is inclined to produce gravity-assisted advancement of the stack as individual blanks are removed for use. Alternatively, a spring loaded mechanism may augment the advancement of the stack. Once each packaging cycle, the platen, which is provided with vacuum devices, accurately accesses the front blank of the stack, grasps this blank with the vacuum devices, removes the blank in a manner to mitigate interblank suction, and delivers this blank to the in-feed opening in the base housing. The platen is mounted on the pivot arm mechanism, which translates mechanically generated up-and-down motion to rotational movement of the platen. The arc of rotation of the platen relative to the arm mechanism is precisely controlled by an interposed sprocket mechanism. As the platen transports the blank to the in-feed opening, a component of the vertical erection mechanism called a former ascends to the top of the opening to receive the blank. The former is provided with vacuum receptors. When the blank is properly positioned over the opening, the vacuum supplied to the platen is released, and then a pulse of air is delivered to the platen causing a snappy release of the blank. Concurrent with this air pulse, vacuum builds-up on the receptors. which then graps the underside of the blank. Therefore, because of the synchronized operation of both the blank feed mechanism and the vertical erection mechanism, accurately registered blanks in the magazine are transported and precisely positioned on the former. In one mode operation, the former remains at its elevated position for a prescribed time interval so that the articles to be packaged may be loaded, either manually or automatically, onto that part of the blank that eventually forms the bottom of the container. Thereafter, under control of the vertical erection mechanism, the blank and articles are drawn downwardly into the machine past a series of folding fingers and plows located on side walls of an erection chamber. The fingers are positioned to cause the minor flaps to fold so that they are entrapped by front and back panels as well as two side flaps folded by the plows. The downward motion forms the blank into a tray containing the articles and orients the top portion of the blank in a vertical sense. In another mode of operation, the former draws the blak partially into the erection chamber before pausing for the prescribed interval. During partial drawdown, the folding fingers and plows erect the blank in tray-like fashion so that during the pause, loose articles may be loaded into the semierected container. Thereafter the vertical erection mechanism draws the tray with articles to the lower position as described in the foregoing paragraph. In either mode of operation, at the bottom of the lowering stroke, vacuum to the receptors is released, and then a puff of air is delivered to the former causing a speedy release of the blank. Simultaneous with the puff of air, vacuum is redirected to the blank feed vacuum devices, which are ready to grasp the next blank in the stack to be processed. In the base housing, the container is now transferred to the glue application mechanism wherein it is pushed horizontally along guide means having peripherally-located folders and plows, which force the top of the blank downwardly and binds two top flaps so that they entrap the minor flaps. As the semierected container proceeds along the guide means, two strategically placed, fixed glue guns supply adhesive to the outer surfaces of the side flaps as well as the front panel. This is accomplished by arranging one glue gun on each side of the horizontal path and aiming each gun at an acute angle relative to the direction of motion of the container. Initially, both guns are provided with sufficient pressure to simultaneously apply a stream of adhesive to each side flap as it moves uniformly past the glue gun. Then, as the corners of the container approach, both guns are momentarily deactivated and, during deactivation, the pressure supplied to the guns is increased. Once the corners pass the immobilized guns, they are again activated to allow each gun to project a stream of adhesive across one-half of the front panel. Thus, with this glue application arrangement, each gun applies approximately the same volume of glue per unit length on the full side flap adjacent to it and half of the front panel. At the end of the glue application stage, lateral movement ceases, and the nearly completed container is transferred to the compression mechanism to await curing. The transfer is accomplished via an elevator that lifts the continer into a compression chamber vertically aligned with the elevator. Upward movement of the container allows fixed forming plows, located at the entrance to the compression chamber, to fold a sealing flap and two top flaps into contact with the glue on the body of the container. compression force is generated by adjustable chamber walls. Latches are interposed in the chamber so that as the elevator descends, the container is retained in the compression chamber. Containers constructed during subsequent machine cycles enter the compression chamber under the last container placed in compression. As the elevator raises a newly formed container, the top container in the queue enters the discharge mechanism, wherein this top container is transferred to an inclined gravity-operated conveyor and trundled to the discharge port in the back wall. Depending on the size of the container, one or more containers may be held in compression. A particular feature of the automatic packaging machine constructed in accordance with the present invention results from the angular orientation of the two symmetrical arranged glue applicator stations that apply adhesive to the three surfaces during one lateral displacement of the blank. During the first stage of gluing, adhesive from one gun projects onto the side flap, which remains equidistant from the glue source while the flap passes the source. Of particular significance, however, is that during glue application to the front panel, the distance between the front panel surface and the glue source increases while lateral movement continues. Increased pressure supplied to the guns during front panel gluing insures that the amount of glue per unit length applied to the front panel is approximately the same as the amount of glue per unit length applied to the side flaps. This is in contrast to prior art packaging machines that rely solely upon an equal surface-to-source distance and a fixed pressure supplied to the guns. This reliance dictates the necessity of two glue application movements and orientations of the blank. These and other objects, features and advantages will be apparent hereinafter from a detailed disclosure of the invention relative to the attached drawings.

Inventors

• 👤 Lawrence J. Talarico

Bibliographic Details