CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of United States Provisional Patent Application No. 61/105559 filed October 15, 2008, the contents of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to a box or case sealer for closing the open ends of cardboard boxes or cartons. The case sealer has a frame with a conveyor for moving filled boxes into a pair of spaced-apart lateral drive belts that function to convey the box through a region comprising a hot melt dispensing system that applies adhesive to the bottom and top flaps in order to allow the flaps to be sealed shut.

BACKGROUND OF THE INVENTION

[0003] In the packaging industry, many products are packed in cardboard boxes or cartons for shipping. One end of the box, namely the bottom, is typically sealed shut with hot melt adhesive or with tape before the box is filled. Alternatively, the bottom of the box may be closed, but not seated shut before the box is filled. After the box is filled, the end and side flaps of the open top end of the box are folded inwardly and downwardly. The box then is typically sealed by applying glue to the inside of the mating surfaces of the folded flaps prior to them being folded shut, or by applying tape to the outside of the flaps after they have been folded shut. If the bottom prior to filling was closed but not sealed, then typically both the bottom and top are sealed with tape following filling.

[0004] There exists in the market place a solution for automatic taping the top and bottom of cases shut after they are filled. One solution is where the sealer is fed by a conveyor from several operator filling stations. Another solution is where the filling station is incorporated into the sealer and as such there is one operator per sealer.

[0005] There also exists in the market place solutions for sealing cases with a hot melt adhesive. Most of these apply the hot melt on the bottom of the case when it is being automatically erected and prior to filling contents, and then on the top of the case after it has been filled. These solutions require two machines (the automatic erector and the top sealer) which are neither compact nor low cost. [0006] There is a need for a compact solution for sealing filled cases with a hot melt adhesive similar to what is currently being accomplished through the use of tape. The current invention addresses this need.

SUMMARY OF THE INVENTION

[0007] The invention provides the art with a compact top and bottom hot melt case sealer with integral hot melt applicator which can meet the needs of single operator or multiple operator feeds. In the practice of the invention, the major flaps on the bottom of a filled case are reopened in order to apply hot melt adhesive, and then sealed.

[0008] One embodiment of the invention is directed to a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the inside surface of each major flap and re-closed, after which the bottom of the box becomes adhesively sealed shut. In another embodiment, the hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the outer surface of each minor flap and re-closed, after which the bottom of the box becomes adhesively sealed shut.

[0009] Another embodiment of the invention is directed to a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the inside surface of each major flap and re-closed, after which both the bottom and top of the box become adhesively sealed shut. In another embodiment, the hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the outer surface of each minor flap and re-closed, after which both the bottom and the top of the box becomes adhesively sealed shut. In a further embodiment, the hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the outer surface of each minor flap and/or inner surface of each major flap and re- closed, after which both the bottom and the top of the box becomes adhesively sealed shut. [00010] The case sealer comprises a frame with a conveyor for moving filled boxes into an area comprising a pair of spaced-apart lateral drive belts and hot melt nozzles. The drive belt moves the box through a region in which a hot melt dispensing system substantially simultaneously applies hot melt adhesive to both the top and bottom flaps to seal both the bottom and top flaps shut. In one embodiment the adhesive is substantially simultaneously applied to the top of the case on the outside surface of the minor flaps and to the bottom of the case on the outer surface of the minor flaps. In another embodiment the adhesive is substantially simultaneously applied to the top of the case on the inner surface of the major flaps and to the bottom of the case on the inside surface of the major flaps. In a further embodiment the adhesive is substantially simultaneously applied to the top of the case on the outside surface of the minor flaps and to the bottom of the case on the inside surface of the major flaps. Yet in a further embodiment the adhesive is substantially simultaneously applied to the top of the case on the inner surface of the major flaps and to the bottom of the case on the outside surface of the minor flaps. [00011] Yet in a further embodiment, an integral part of the case sealer is a hot melt dispensing system. The integrated hot melt dispensing system comprises hot melt adhesive, a melt tank having an interior cavity adapted to receive the adhesive and, optionally, an automatic feed device integrally connected to the melt tank. In one embodiment, the system comprises heating elements that are controlled or programmed to reach a maximum operating temperature of 250 ⁰ F. [00012] In one embodiment, integrated hot melt dispensing system comprises an automatic dispensing unit for maintaining a supply of hot melt adhesive in its solid form, a supply connector which supplies the solid adhesive from the automatic dispending unit to the interior cavity of the melt tank, a melt tank which comprises heating elements, a transfer hose connected from the melt tank to the nozzle, at least one nozzle mounting port including a dispensing orifice which is opened and closed by a valve, and at least one nozzle for dispensing molten hot melt adhesive from the dispensing orifice. [00013] In one embodiment, the case sealer is a random case sealer, wherein the apparatus adjusts automatically to accommodate the size of the box, in particular, the spaced apart laterally positioned pair of drive belts adjust to suit the size of the box and the hot melt dispensing equipment's placement of adhesive onto the flaps.

[00014] Another embodiment of the invention is directed to a packaging method using the case sealer of the invention. The method of the invention comprises constructing the box, closing but not sealing shut the bottom of the box, filling the box with material to be packaged, moving the filled boxes into an area of a box sealer comprising a pair of spaced-apart lateral drive belts and hot melt nozzles. Moving the box via the drive belt through a region in which a hot melt dispensing system applies adhesive to the bottom and top flaps, and then closing the flaps whereby the bottom and top ends of the box become sealed. In the practice of the invention, hot melt is substantially simultaneously applied to the top and bottom flaps. In one embodiment the adhesive is substantially simultaneously applied to the top of the case on the outside surface of the minor flaps and to the bottom of the case on the outer surface of the minor flaps. In another embodiment the adhesive is substantially simultaneously applied to the top of the case on the inner surface of the major flaps and to the bottom of the case on the inside surface of the major flaps. In a further embodiment the adhesive is substantially simultaneously applied to the top and/or the bottom of the case on the outside surface of the minor flaps and to the top and/or the bottom of the case on the inside surface of the major flaps. Yet in a further embodiment, the adhesive may be applied independently on the inner surface of the major flap and the outer surface of the minor flap for the top and the bottom of the case.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[00015] Figure 1 is a side view of one embodiment of the case sealer of the invention. [00016] Figure 2 is on overhead view of the bottom half of the case sealer shown in Figure 1 [00017] Figure 3 shows a filled box as it receives hot melt adhesive as it is moved through the adhesive application section of the case sealer.

DETAILED DESCRIPTION OF THE INVENTION

[00018] The invention provides the art with an alternative method of sealing a box wherein both the top and bottom flaps of a filled box are sealed shut with a hot melt adhesive. In accordance with the practice of the invention, the box is erected, filled, and then both the bottom and top is sealed shut using a hot melt adhesive.

[00019] The case sealer of the invention comprises a frame having a longitudinal axis that includes an entrance conveyor for moving boxes entering the case sealer along the axis, a pair of longitudinal spaced-apart, lateral belt drives is located to receive boxes from the entrance conveyor and to move them into and out of a hot melt dispensing region and onto a sealing platform.

[00020] A box or case is first erected in such a manner that the bottom flaps are closed but not sealed and the top flaps remain open. The box is filled, and then sealed using the case or box sealer of the invention. The case sealer of the invention may be semi-automatic, in that the inner flaps of the top of the box are manually folded closed prior to being conveyed into the case sealer. Alternatively, the case sealer may be automatic, wherein the case sealer comprises a "flap kicker" that folds the inner top flaps into the closed position as it is being conveyed into the region where adhesive is applied to the flaps. [00021] The case sealer of the invention comprises three distinct regions: entrance conveyor, adhesive application region and sealing platform. Entrance Conveyor

[00022] The entrance conveyor comprises a plurality of interdigitating rollers positioned at a downward angle. The downward angle will generally range from about 5 degrees to about 10 degrees from horizontal level, typically about 6 degrees. The entrance conveyor allows the major outer bottom flaps to partially drop open while the inner flaps remain in a substantially closed position, thereby retaining the contents within the confines of the box. Adhesive application region

[00023] The box then enters the adhesive application region comprising a floor that is open in the center, the center being flanked by a pair of peripherally located angled floor regions and a pair of laterally positioned drive belts that pushes or otherwise moves the box through the hot melt application region. The areas of angled floor (also referred to herein as the bottom major flap guide bars) allow the major flaps of the folded box to drop further in order to receive hot melt adhesive. The angle from each bottom major flap guide bar to horizontal will generally range from about 1 degrees to about 45 degrees, typically about 5-20 degrees, more typically about 10-15 degrees. As the box enters the adhesive application region, and the bottom major flaps fall further, additional support to retain the inner minor flaps in the closed position is provided by a plow.

[00024] The plow, which may comprise a pair of applicator nozzles, is adapted and positioned to provide temporary support to the minor bottom flaps and/or contents of the box once the major flaps drop to receive adhesive. A plurality of hot melt dispensing nozzles, located both above and below the adhesive application region, is present to apply adhesive to bottom and top flaps as the box is moved through the adhesive application region. During transport of the box through the adhesive application region, a pair of nozzles applies hot melt adhesive to the outside surface of each of the closed minor flaps of the top of the box while a second pair of nozzles applies hot melt adhesive to the outside surface of the closed minor flaps of the bottom of the box. The pair of nozzles can be positioned to apply the hot melt adhesive to the inner surface of each of the open major flaps of the top of the box and the bottom of the box. The nozzles can also be positioned to apply the hot melt adhesive to the outside surface of each of the closed minor flaps of the top of the box while the second pair of nozzles applies hot melt adhesive to the inner surface of the open major flaps of the bottom of the box. The nozzles can further be positioned to apply the hot melt adhesive to the inner surface of each of the open major flaps of the top of the box while the second pair of nozzles applies hot melt adhesive to the outer surface of the closed minor flaps of the bottom of the box. The pair of nozzles can also be independently positioned so that each nozzle dispenses the hot melt adhesive to either the inner surface of the open major flaps or the outer surface of the closed minor flaps. Sealing Platform

[00025] Following application of adhesive, the box is conveyed to a region comprising a plurality of flat rollers. As the box leaves the adhesive application region the bottom flaps are closed as the box is moved onto the rollers, and the top flaps are closed and, preferably, compressed to seal both the top and bottom of the box.

[00026] The case sealer of the invention includes an integrated system for processing and dispensing a hot melt adhesive. The system is particularly useful when adapted to process and dispense adhesives formulated for application at low temperatures, i.e., temperatures of 29O ⁰ F or less, more typically temperatures of 16O ⁰ F to 260 ⁰ F, even more typically 170 ⁰ F to 200 ⁰ F . While the invention is not to be limited to the use of low application temperature hot melt adhesives, such adhesives can be transported, processed and dispensed for use in a safer, more economical way.

[00027] The integrated hot melt adhesive dispensing system is positioned and adapted to dispense hot melt adhesive to the end flaps of the boxes. Use of a low temperature hot melt means that the end user would not suffer from problems traditionally associated with the use of conventional (high temperature application) hot melt and non integral hot melt applicators. Such problems include, e.g., hot melt charring which blocks applicator nozzles and causes downtime, hot melt charring which requires tank flushing, high temperature hot melt which can cause safety issues, high temperature hot melt which can cause accelerated wear on the applicator, and multipurpose applicators which are not designed specifically for this application and which therefore are too complex to operate and maintain. [00028] The integrated hot melt adhesive dispensing system comprises a hot melt adhesive product, a melt tank preferably with an integrated level control and, optionally, a high efficiency automatic dispensing unit.

[00029] The adhesive product used in the system of the invention is not particularly limited. Virtually any low application temperature hot melt adhesive may be used in the practice of the invention. Base polymers suitable for use in formulating low application hot melt adhesives include amorphous polyolefins, ethylene-containing polymers and rubbery block copolymers, as well as blends thereof. Hot melt adhesive compositions based on ethylene/vinyl acetate copolymer, isotactic or atactic polypropylene, styrene-butadiene, styrene-isoprene, or styrene-ethylene-butylene A-B-A or A-B-A-B block copolymers or mixtures thereof may be used. Blends of any of the above base materials, such as blends of ethylene n- butyl acrylate and ethylene vinyl acetate and ethylene vinyl acetate and atactic polypropylene may also be used to prepare hot melt adhesive compositions. In all cases, the adhesives may be formulated with tackifying resins, oils plasticizers, waxes and/or other conventional additives including stabilizers, antioxidants, pigments and the like.

[00030] When the adhesive dispensing system is in operation, the hot melt adhesive, in solid form, is continuously fed, conveyed or dispensed from a solid material staging area or depot, also referred to herein as an automatic dispensing unit or automatic feed tank, drum or bin, via a supply passage or conduit such as a tube, hose or the like, to the melt tank.

[00031] In one embodiment, conveyance into the melt tank is controlled by an automatic feed tank or automatic dispensing unit that is integrally connected to the melt tank. The automatic dispensing unit automatically fills the melt tank in response to a level detector present in the melt tank. [00032] In the melt tank, heating elements heat the adhesive contained therein to a predetermined set temperature. Use of a low application temperature hot melt adhesive and temperature controls of the invention enable the positioning of the dispensing unit closer to the melt tank.

[00033] In one embodiment, an integrated control panel is used to control the adhesive level and to control the temperature. When using a low application hot melt adhesive, the control will be set to prevent temperatures higher than 290 ⁰ F. In one embodiment, the control will be set to prevent the temperature for going above about 250 ⁰ F. In another embodiment, the control will be set to prevent the temperature for going above about 200 ⁰ F.

[00034] An audible alarm will preferable be present to indicate when the solid hot melt dispensing unit is empty, when the melt tank is empty and when the temperature is outside of the desired or predetermined limit.

[00035] The system will also comprise a hot melt dispensing port, a pump, and a transport hose for transporting molten adhesive to the application nozzles. When using a low application temperature hot melt adhesive, the molten hot melt can be transported up to 10m, more typically up to 4m, from the melt tank to the application nozzles.

[00036] In one embodiment, the system comprises a hot melt adhesive, an automatic dispensing unit, a supply connector and a melt tank, where the solid hot melt adhesive is automatically fed by way of an automatic dispensing unit (automatic feed) into a heated melt tank, where the adhesive melts and is maintained at a predetermined temperature. Melted adhesive is maintained at a predetermined level by level detectors present in the melt tank. Molten adhesive is then pumped from the melt tank through a mounting port, bore or outlet which includes a dispensing orifice which is opened and closed by a valve stem, through transfer hose to a nozzle for dispensing molten hot melt adhesive onto the surface of a box. [00037] The shapes of the unit and/or parts making up the automatic dispensing unit and melt tank are not particularly limiting. The automatic dispensing unit and/or melt tank may comprise a single wall (e.g., is cylindrical in shape), or a plurality of walls (e.g., is square, rectangular, or the like). [00038] The automatic dispensing unit is integrally linked to the melt tank and these system components may be manufactured of the same or different material. Solid adhesive, in the form of pellets or other such conventional form, is introduced into the dispensing unit via an adhesive inlet valve, e.g., by blowing or other conventional means. Means for removing air accompanying the introduction of the solid adhesive into the automatic dispensing unit may be used. If desired, baffles or other such means may be present in the automatic dispensing unit which function to direct solid adhesive toward the melt tank and/or deflect heat. [00039] The melt tank comprises heating means, and may include a grid heated via either cartridge or band heater. A plurality of heat elements may be employed throughout the tank to optimize melt down and molten feed rates. The heaters may be positioned in such a way to provide heat to both the adhesive in the hot melt tank as well as the pump mechanism. Alternatively separate sets of heating elements may be used to provide heat to the adhesive in the hot melt tank and to adhesive in the pump mechanism. Heating elements will be thermostatically controlled and will comprise circuitry for providing electrical power.

[00040] The melt tank is connected to a dispensing unit through a one way check valve which allows material into the molten chamber of the pump (on the piston's return stroke) while restricting reverse flow when under pressure from the pump (e.g., due to forward pumping stroke of piston). Dispensing may also be accomplished via a gear pump, for example.

[00041] The invention provides a case sealer that comprises a closed system for automatically processing and dispensing hot melt adhesive at multiple sites, wherein the adhesive level in the melt tank will be maintained at a predetermined level adhesive level using an automatic feed device and level sensor. The closed system prevents contamination and helps to keep work areas safe and clean. Moreover, when using a low application temperature adhesive the life of consumable parts such as nozzles, filters and modules is prolonged and wear observed in hoses, pneumatic assembly, vibrator, feeder pneumatic assembly as well as control card, power card, thermostat, RTD, level sensor control board decreases.

[00042] One embodiment of the invention is directed to a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the inside surface of each major flap and re-closed, after which the bottom of the box becomes adhesively sealed shut. Another embodiment of the invention is directed to a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive to the outside surface of each minor flap and re-closed, after which the bottom of the box becomes adhesively sealed shut. In a further embodiment, a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive substantially simultaneously to the top and bottom flap to the outside surface of each inner flap and re-closed, after which the bottom of the box becomes adhesively sealed shut. Yet in a further embodiment, a hot melt case sealer wherein previously closed but unsealed major bottom flaps of a filled case are re-opened in order to apply a hot melt adhesive substantially simultaneously to the top and bottom flap to the inside a surface of each major flap and/or the outside a surface of each minor flap and re-closed, after which the bottom of the box becomes adhesively sealed shut.

[00043] The nozzles may be positioned to allow the hot melt adhesive to be applied at either the minor and/or the minor flaps for both the top and the bottom of the box. Moreover, the nozzles may be independently positioned to dispense hot melt adhesive on different or the same flaps of the top and the bottom of the box.

[00044] Various patterns and amounts of the hot melt adhesive may be dispensed from the nozzle.

The patterns may be controlled by dispensing the hot melt adhesive in a desired pattern by moving the nozzles and/or moving the box in the adhesive application region on the conveyor belt. The amount of hot melt adhesive dispensed is controlled by the length of time the nozzles dispense the adhesive in each position and/or by varying the pump pressure. The specific pattern design and the amount of adhesive emitted can be mechanically and/or electronically controlled.

[00045] The invention will hereinafter be described by reference to the accompanying drawing

Figures.

[00046] Figure 1 represents a side view of one embodiment of a case sealer of the invention. Figure

2 is an overhead view of a case sealer, particularly the bottom portion of the case sealer, of the invention.

Figure 3 shows a filled box as it receives hot melt adhesive as it is moved through the adhesive application region.

[00047] Referring to Figure 1 , the case sealer comprises a frame having a longitudinal axis that includes an entrance conveyor (1), an adhesive application region (2) and a sealing platform (3). The case sealer may be stationary or may be supported on casters (4) to allow the case sealer to be easily moved to desired location.

[00048] The entrance conveyor (1 ) moves boxes along the longitudinal axis and into the adhesive application region (2). The entrance conveyer (1) comprises a series of interdigitating rollers shown in more detail in Figure 2 (5 and 6). A center rail and a pair of longitudinal spaced-apart, lateral belt drives (7) is located to receive boxes from the entrance conveyor (1) and move them into and out of a hot melt dispensing region (2). The case sealer comprises a "flap kicker" (20a) that folds the inner minor top flaps into the closed position (20b) as it is being conveyed into the region where the hot melt adhesive is applied to either or both the minor or major flaps. The hot melt adhesive is emitted from the nozzles (16) attached to top minor flap guard (19). One top nozzle (16) is shown. After the adhesive has been applied, the box is moved to the sealing platform (3). A compressor (11) is used to shut and seal the box. [00049] Referring to Figures 1 and 2, an integral part of the case sealer is a hot melt dispensing system. The integrated hot melt dispensing system comprises an automatic dispensing unit (24) for maintaining a supply of hot melt adhesive in its solid form, a supply connector (25) which supplies the solid adhesive from the automatic dispensing unit to a melt tank (22), where the solid adhesive is melted into a molten state. A transfer hose (21) transfers the molten hot melt adhesive from the melt tank to the application nozzles (14, 15, and 16) where the adhesive is dispensed onto a box. [00050] Referring to Figures 2 and 3,, the adhesive dispensing region (2) comprises a floor that is open in the center (8), the center being flanked by a pair of peripherally located angled floor regions, also referred to as the bottom major flap guide bars (9). The bottom nozzles (14, 15) dispense hot melt adhesive onto the bottom flaps of the box. Following application of adhesive, the box (10) moves to the sealing platform (3) where the exterior side of the bottom minor flaps contact adhesive applied to the interior portion of the bottom major flaps and the top flaps are folded and compressed using a compressor (11) whereby the box is sealed shut. The sealing platform (3) receives the box and this may be made of a movable belt or a static platform.

[00051] Figure 3 shows the box as it receives hot melt adhesive as the box moves through the adhesive application section of the case sealer. Referring to Figure 3, the areas of angled floor (major flap guide bars) (9) allows the major flaps (12) of the folded box (10) to drop in order to receive hot melt adhesive (13) on the other minor flap. A plurality of hot melt dispensing nozzles (14, 15, 16, 17), located both above and below the box in the adhesive application region are present to apply adhesive to the flaps of the case as it moves through the adhesive application region. During transport of the box through the adhesive application region, a pair of top nozzles (16, 17), attached to the top minor flap guard (19), apply hot melt adhesive to the each of the closed minor flaps (181), open major flaps (18J), one closed minor flap and one open major flap or to both closed minor flaps and open major flaps of the top of the box. Also a second pair of nozzles, bottom nozzles (14, 15) attached to the center rail (26), apply hot melt adhesive to the inside surface of each of the closed minor flaps (121), open major flaps (12J), one closed minor flap and one open major flap or to both closed minor flaps and open major flaps of the bottom of the box (12). In one embodiment, a center rail (26) comprising a pair of nozzles, is adapted and positioned to provide temporary support to the minor bottom flaps and/or contents of the box once the major flaps drop to receive adhesive. A flap kicker may be present which will be spaced above and the lateral conveyors. The flap kicker is adapted to engage and hold box flaps shut and is adapted to mount an adhesive nozzle centrally thereon for sealing the box flaps shut.

[00052] Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only, and the invention is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled.