FIELD OF THE INVENTION
The present disclosure relates generally to the art of machines that process rolls of bags. More specifically, it relates to a bander.
BACKGROUND OF THE INVENTION
Rolls of bags (such as tall kitchen bags) made from film are common in the industry. Bags may be made using various machines such as a rotary overlap machine (see U.S. Pat. No. 5,377,929, Gietman et al., hereby incorporated by reference, and U.S. Pat. No. 8,029,428, Selle et al, hereby incorporated by reference). Some machines include a winder, and other machines are used with separate winders. High speed winders are described in U.S. Pat. No. 7,578,779 and US 2009-0019817 A1, both Selle, et al., and hereby incorporated by reference. The speed of some bag making machines and winders can be 600 feet per minute, which makes about 240 bags per minute, for 30 inch tall kitchen bags.
After being wound into a roll bags are packaged. Rolls in boxes are preferred in some markets, but in other markets less packaging is preferred. Providing a paper or plastic band around the roll to hold the roll in place uses little packaging, reducing waste and cost of materials. Also, it provides a location (the band) for the manufacturer to advertise. Paper bands typically have glue, which is wetted and then wrapped around the roll. A quick setting glue dries quickly, allowing the roll to moved and made ready for shipping.
However, wetting and placing the band on a roll can be difficult, and it is difficult to do so at speeds commensurate with the speeds bags are produced. Rolls of bags can be produced in 1.5 seconds (or 40/minute). The banding has been performed by hand. This can be slow, costly and unreliable. Automatic banders have also been used, but are limited in speed to 10 rolls per minute. Thus, the bander is often the speed limiting step for the bag machine and winder.
Accordingly, and automated bander that can effectively band rolls of bags at the speed the bags are produced is desired.
SUMMARY OF THE PRESENT INVENTION
According to a first aspect of the disclosure a machine applies bands to rolls of bags. The machine includes two or more banding stations and a roll diverter. A roll path includes a source of the rolls of bags, followed by the roll diverter, followed by the banding stations. Each banding station includes a cradle that receives a roll, and includes a band applicator. The band applicator receives bands and applies the band to the roll in the cradle. The roll diverter receives the rolls of bags from the source, and selectively directs each rolls of bags into one of the banding stations such that any particular roll is diverted into only one of the stations, and such that some of the rolls are diverted into each banding station.
According to a second aspect of the disclosure a method for banding rolls of bags includes receiving a plurality of rolls of bags, and directing some of them into a first of a plurality of banding stations. Additional rolls of bags are directed into additional banding stations. The directing is done sequentially such that each banding station receives one of the plurality of roll of bags before any given banding stations receives a second. In each banding station a roll of bags is cradled, and a band applied thereto.
The winding includes a bag machine and/or winder in various embodiments.
There are two, three, or more banding stations in various embodiments.
Each band applicator includes a liquid applicator that extends in the cross direction and applies liquid to only part of the band in the cross direction, and does not apply liquid the rest of the band in the cross direction in another alternative.
Each band applicator includes a vacuum conveyor that conveys the bands in one embodiment.
Each banding station includes at least one mandrel disposed to hold the roll in one alternative.
The banding stations includes a source of air that directs the first band in another alternative.
The band applicators includes flexible fingers that guide the bands in one alternative.
The source provides the plurality of rolls of bags at a first given rate, and banding stations operate at a second given rate, and the ratio of the first given rate to the second given rate is less than the number of banding stations in one embodiment.
The machine includes two winding stations in one alternative.
The two winding stations each wind in a different direction, and the rolls are directed to a banding station based at least partially on which direction the roll was wound in another alternative.
Other principal features and advantages of will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is schematic of a machine described herein;
FIG. 2 is schematic of a bander described herein;
FIG. 3 is schematic of a banding station described herein;
FIGS. 4A-4F illustrates one process of applying a band to a roll;
FIG. 5 is schematic of a bander described herein;
FIGS. 6A-6E illustrates a second process of applying a band to a roll;
FIG. 7 is schematic of a bander including a diverter described herein;
FIGS. 8A-8E are schematics of a liquid applicator described herein;
FIG. 9 is schematic of a suction cup described herein; and
FIG. 10 is schematic of a mandrel described herein
Before explaining at least one embodiment in detail it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Like reference numerals are used to indicate like components.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
While the present disclosure will be illustrated with reference to particular banders used with particular bag machines and winders, it should be understood at the outset that the bander, bag machine and winder can also be implemented with other designs, and the bander can be implemented without the bag machine or winder.
Generally, the bander described herein in includes multiple banding stations. That allows each bander to operate at a lower speed than the over all production rate of the bander. If there are four banding stations, the speed of the bander will be four times the speed of one station, for example. This allows the bander to keep pace with the upstream source of rolls, even if the source is a high speed bag machine and winder, such as a 600 fpm bag machine and a winder with two 300 fpm winding stations.
Each banding station is preferably identical (except for roll winding orientation) and includes a cradle for holding the roll, and a band applicator for applying the band. The banding station preferably includes at least one mandrel that holds the roll, and the applicator preferably includes flexible fingers that wrap the band about the roll. The band is preferably conveyed using vacuum conveyors that helps wrap the band about the roll and preferably include a source of air directed to the band that forces the band into the cradle before the roll enters the cradle. The band preferably includes glue that is activated when wetted. A liquid applicator applies water to the band to activate the glue. The liquid is preferably applied intermittently in the cross direction (relative to the movement of the band), so that the dry portions help provide stability for conveying the band.
FIG. 1 is a schematic of a machine 100 that includes a bag machine 101, a winder 102, and a bander 103. Bag machine 101 forms bags from a film, and is preferably a rotary bag machine such as that shown in U.S. Pat. No. 5,377,929. The formed bags are provided to winder 102 that is preferably like those described in U.S. Pat. Nos. 8,029,428 7,578,779. The preferred embodiment provides that winder 102 includes two winding stations 104 and 105. Alternatives provide for 1 or more than two winding stations. Winder 102 is preferably consistent with prior art winders, and can operate as fast as bag machine 101. Bag machine 101 preferably operates at up to 600 fpm, and produce about 240 side seal bags/minute. Forty rolls of bags can be made in one minute in the preferred embodiment.
After the rolls 108 are formed they are received by bander 103. Bander 103 includes a conveyor 110, and a plurality of banding stations 112-114, each preferably 6-24 inches apart. There are eight banding stations shown, although this embodiment includes using only four banding stations. Either stations 112 are used (and provided), or stations 114 are used (and provided), depending on the direction each roll is wound. The number of stations shown is merely exemplary. Alternatives provide more or fewer banding stations. The formed rolls 108 are provided to conveyor 110. Alternatives provide that a source of rolls other than a winder and/or a bag machine are used. For example, the rolls could be wound on one machine, and the banded on another, and the rolls can be made at a nearby or distant location.
As rolls 108 move along conveyor 110 they are selectively directed to one of the banding stations. A roll diverter (shown in FIG. 7) diverts roll 108 off of conveyor 110 at the appropriate location to direct roll 108 to a selected banding station. In one embodiment roll 108 is pushed so that it rolls off conveyor 110. If rolls are wound such that they would unroll when pushed to the left, then banding stations 112a-112d are used. If the rolls are wound such that they would unroll when pushed to the right, then banding stations 114a-114d are used. The preferred embodiment provides for the machine to have only one set 112 or 114 of banding stations. Generally, if rolls 108 enter conveyor 110 from one side the should be rolled back to that side. However, if a carousel is sued by winder 102, then rolls 108 should generally be rolled off to the opposite side they came from because the carousel flips the rolls.
Diverting rolls in the selected direction reduces the likelihood that the roll will roll unwind as its being diverted into a banding station. Also, the diverter would preferably divert rolls using a pattern such as 112a, 112c, 112d, 112b (and repeat) to make sure that each banding station 112-114 has sufficient time to complete the banding operation. The diverter includes mandrels to hold the rolls, and/or paddles or ramps to direct the rolls in various embodiments. One embodiment provides that rolls of bags can be produced in 1.5 seconds (or 40/minute), and that banding stations 122-114 can each operate at up to 10 rolls per minute. Thus, the ratio of the winding speed (40/minute) to banding station speed (10/minute) is 4. By providing 4 banding stations the bander can keep pace with the winder (because the bander has four stations at 10/minute and can collectively band 40/minute). Generally, it is desirable to have at least as many banding stations as the ratio of winder to banding station speed, so that the bander can keep pace with the source of rolls.
FIG. 2 shows an embodiment of bander 103 used when winder 102 includes winding stations that wind rolls in opposite directions. Rolls 108 are directed to one of winding stations 112a-112b or 114a-114b based on the winding direction (so that as roll 108 rolls off of conveyor 110, the roll does not unroll). Thus, as winding stations 104 and 105 alternately provide a completed roll 108 to conveyor 110, the diverter would alternately divert rolls to 112 and then 114. Also, the diverter would preferably divert rolls using a pattern such as 112a, 114b, 112b, 114a (and repeat) to make sure that each banding station 112-114 has sufficient time to complete the banding operation. Bad rolls are rejected off the end of conveyor 110 and are not banded.
Banding stations 112-114 and winding stations 104-105 are vertically stacked, and/ or horizontally separated in various embodiments.
FIG. 3 is a schematic of one banding station 112-114. Banding stations 112-114 include a cradle 401 that holds a band 402 (and will hold a roll 108), fingers 404 and liquid applicators 405. Fingers 404 are preferably articulated flexible fingers such as Festo FinGripper® or SoftGripper®. Fingers 404 are used to guide the ends of band 402 over roll 108 when roll 108 is in the cradle. After a roll has been banded, a new band 402 is conveyed (as described below) into cradle 401. Band 402 is conveyed from the right, past liquid applicators 405. Liquid applicators 405 extend in the cross direction (relative to the movement of band 402) and apply liquid intermittently in the cross direction so that enough glue on band 402 is activated to allow band 402 to secure to itself when wrapped about roll 108. Preferably, enough of band 402 remains dry that it is not too wet and floppy to convey to cradle 401 and to wrap about roll 108. After band 402 is conveyed into cradle 401, roll 108 (not shown in FIG. 3) is directed or diverted into cradle 401 over band 402. The ends of band 402 are wrapped about roll 108, and secured to itself. Alternatives provide that the liquid applied activate glues on band 402, or be glue itself.
FIG. 4 shows one banding procedure. FIG. 4A corresponds to FIG. 3, but for clarity cradle 401 is omitted. Band 402 is conveyed by vacuum conveyors 407 (suction cups, e.g.). An air source 409 blows air at band 402 so that band 402 conforms to cradle 401. FIG. 4B shows roll 108 placed over band 402. FIG. 4C shows fingers 404 moving the leading end of band 402 about roll 108. Suction cup 407 has positioned the tail end of band 108. FIG. 4D shows fingers 404 moving the trailing end of band 402 over the leading end of band 402. Suction cup 407 holds the tail end of band 108. FIG. 4E shows fingers 404 that had been moving the leading end of band 402 withdrawn, and FIG. 4F shows fingers 404 completing the wrapping of band 402 about roll 108.
Vacuum conveyors 407 of FIGS. 4 and 6 preferably are applied to the paper band in a dry stripe (but this is not required). Three vacuum cups and 4 articulating fingers are used in the preferred embodiment to fold over, wrap, and hold one end of the sticky band against the roll of bags until it stays in place by itself due to the adhesive drying sufficiently. The process is repeated for the other end of the paper band to create a finished banded roll of plastic trash bags.
FIG. 5 shows an embodiment of bander 103 that has vertically stacked banding stations. Two rolls of banding paper 501 and 502 provide the bands to each station, and each station includes a cradle 401, such as that shown in FIG. 3 and operated as shown in FIG. 4 Ramps 503A-503D have a roll 108 diverted thereto, and allow roll 108 to roll into cradle 401. In practice only one ramp 503A-503D will receive a roll 108 at a given time. After banding has been completed, ramps 503A-503D can be lowered to the dashed position, and banded roll 108 can be dropped into a bin below the ramps. Rolls 108 are provided to the ramps in the sequence of 503A, 503C, 503B, 503D, to avoid problems with nip timing.
FIG. 6 shows one banding procedure for another embodiment. FIG. 6A shows vacuum conveyors 407, and liquid applicators 405. Band 402 is shown conveyed by vacuum conveyors 407 in FIG. 6B, and air source 409 blows air at band 402 so that band 402 conforms to cradle 401. FIG. 6C shows roll 108 placed over band 402, having reached cradle 401 via ramp 503. FIG. 6D shows roll 108 being unwound so that the tail end of roll 108 maybe straightened (for better banding). The roll is then wound straight and tight and in FIG. 6E the band is wound about roll 108 and about itself. A mandrel such as that described below with reference to FIG. 10 is preferably used for unwinding and rewinding the roll.
FIG. 7 shows another embodiment of bander 103 that includes four banding stations 701A-701D. The design of each banding station 701A-701D is preferably a design shown in FIG. 4 or 6, but can be a different design. A roll diverter 705 is shown that diverts rolls 108 to the desired and selected banding station. Diverter 705 receives rolls from winding stations 104 and 105. Diverter 705 is shown in four positions, each corresponding to diverting roll 108 to one banding station. When diverter is in position 705A, roll 108 is diverted to banding station 701A. When diverter is in position 705B, roll 108 is diverted to banding station 701B. When diverter is in position 705C, roll 108 is diverted to banding station 701C. When diverter is in position 705D, roll 108 is diverted to banding station 701D. Other diverters may be used, and for a horizontal conveyor diverter 705 may be a simple design that pushes roll 108.
Liquid applicators 405 (FIGS. 3, 4, 6) are shown in more detail in FIG. 8, and preferably apply water in stripes (so that a cross direction profile alternates between wet areas 803 and dry areas 805. The striped pattern to give the paper band extra strength and robustness which is helpful in the downstream banding operations. Applicators 405 spray water onto band 402. The band typically has a low cost water activated adhesive, similar to a postage stamp of old. The water can be sprayed in any direction desired and can be sprayed in multiple spots (thus creating stripes of sticky areas) as the paper band travels past. A fine mist in a 0.25″-1.0″ pattern is preferred. One preferred spraying system uses a pressurized water tank such as available from Spraying Systems Company in Wheaton Ill. A 0.25″-2.0″ space of no water between wet stripes is desirable. This pattern improves the process by: increasing the paper tear strength, increasing paper bridge strength as it is pushed over unsupported gaps, reducing paper curl due to water/glue activation; maintains a flatter paper shape when wet, creating a wider operating window for the amount of water applied because excess water is absorbed later in the process at the dry stripes, allowing a dry area for guide fingers to be used without sticking to adhesive, reducing wrinkling which improves the aesthetics of the advertising label/band, and improving the end users ability to pick off the paper band so they can use the bags. After the water mist is sprayed on it is then wiped with a wiper or brush 801 to force the water into micro droplets and adhere better to the surface texture of the adhesive. A wiper can be created by many means such as: horse hair bristle brush with tapered cut tip; plastic sheet; rubber sheet; metal sheet; or by blowing air to act as a wiper. Adding heat to the water can improve the water wiping characteristics. Adding a chemical agent to the water can improve the water wiping characteristics.
Alternatives are shown in FIGS. 8B-8E. FIG. 8B shows applicators 405 implemented with brushes attached to a water source 810 (or other source of liquid). The amount of liquid applied is preferably metered, such as by using flow limiter FIG. 8C shows rollers implementing applicators 405. The gap between rollers 405 determines the width of the dry areas and can be adjusted as desired. FIG. 8D shows applicators 405 implemented with sponges and FIG. 8E shows rollers 405 receiving water from an adjustable source 820 (having High, Medium and Low settings).
FIG. 9 is one embodiment of suction cup or suction conveyor 407. It can be a suction cup from Piab, F20 Silicone, G⅛″ male, with mesh filter. Multiple conveyors 407 are preferably used to convey band 402.
FIG. 10 shows a chuck or mandrel 1001 used to hold roll of bags 108 while banding or to divert roll 108 to the banding position. The mandrel can be used in conjuction with or instead of the cradle and/or diverter described above. The preferred shape for mandrel 1001 for a roll from a one inch diameter winding spindle is approximately 0.25″ radius to 0.5″ radius semi-circle. That radius can be extended outward on the tip of a cylindrical shape so the resulting protrusion is 0.5″to 1.0″ long. An alternative includes adding a cone shape or taper. The mandrel should hold rolls tight and concentrically without damaging or crushing the roll of bags, preferably to grips the film to assist with re-winding the roll extra tight before banding begins. The preferred material is a 40-80 durometer rubber-like material. Other embodiments use silicone, nitrile, etc. The preferred embodiment includes a secondary shape on which the mandrel is mounted, including a shoulder for the roll to butt up against. The shoulder size preferably allows a sufficient grip on the roll without getting in the way of the band application. The shoulder diameter is preferably is about 1.25″ for winding small count rolls that are 1.50″ in diameter. For larger count rolls the shoulder diameter is preferably 0.25″ smaller than the roll. To prevent loose film from getting captured between the mandrel and the roll end it the shoulder starts tapering away from the roll end for large diameter rolls.
The tail straightening shown in FIG. 6D can be performed using two of the mandrels to grab the roll from each end after the roll is dropped into the semi-circle like cradle or cavity. Once the roll is securely held by extending the mandrels the cradle can be opened or backed away from the roll. An air curtain (preferable an ARTX brand venturi style) located 0.06″-0.75″ from the roll surface is used to blow the outer bag tail in a desired direction. The roll is turned and unwound 1-3 revolutions via the mandrels. This allows any disturbed or wrinkled or telescoped tails to straighten out in the air stream. The mandrels then re-wind the tail straight and true. Applying slight tension (⅛-1 pound of drag force) on the tail improves the final re-wind so it is as tight as possible. Having a tight wind also improves the ability to band tightly. The semi-circular cradle can apply the desired drag force.
Numerous modifications may be made to the present disclosure which still fall within the intended scope hereof. Thus, it should be apparent that there has been provided a method and apparatus for banding rolls of bags that fully satisfies the objectives and advantages set forth above. Although the disclosure has been described specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
Patent Application
20170267384
