Carton forming apparatus with servo control

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Patent issued

01/12/1993

Inventor(s):	Pike, Brian C. Harston, John C.
Assignee	Kliklok Corporation (Decatur, GA)
Application	No. 07/761,857 filed on 09/10/1991
Current US Class	53/55, 53/506, 53/563, 493/167
Field of search	53/55, 53/56, 53/57, 53/58, 53/506, 53/505, 53/77, 53/207, 53/462, 53/563, 493/167
International Classes:	B31B 174, B31B 346, B65B 5706
Examiners
Primary	Coan James F.
Attorney, agent or firm:	King & Schickli
US patent references	3260174, 3955482, 4722168, 4930290, 4955176, 5010712
Foreign patents	8905530 (03/10/1989, GB), 1262888 (03/31/1961, FR)

An apparatus for forming paperboard cartons from flat blanks is provided.The carton blanks are fed from a magazine to the face of a forming die, areciprocating plunger is provided to push the blank through the dieforming the carton, and an endless conveyor receives the carton afterbeing stripped from the bottom of the die. A servo drive means for theplunger, blank feeder and conveyor are each independently driven by aninfinitely variable speed electric motor. A programmable logic controlleroperates the servo drive means, whereby the plunger, feeder and conveyorcan be infinitely varied to fit the forming action desired. The servodrive means preferably takes the form of a variable speed, electronicservo motor including an encoder and a tachometer feedback. Product sensormeans detect product availability and carton sensor means detects cartonavailability with both sensor means also being controlled by theprogrammable logic controller.
BACKGROUND OF THE INVENTION
This invention relates to packaging machinery of the type in which apaperboard carton is first formed from a flat paperboard blank by aplunger reciprocating through a forming die, the formed carton with opentop being stripped from the retracting plunger and deposited on to aconveyor system at another position along which a product is deliveredinto the carton, which then receives a separate lid at a further positionor has integral flaps folded down and secured.
With the usual cyclical mechanical drive for the plunger in the prior artcarton formers, the timing for the blank feeder, and the conveyor systemand product delivery, is all set from the timing of the plunger. Also, themotion of the plunger is rigidly determined by the drive means. Even ifthe length of stroke of the plunger can be adjusted, it is unlikely tovary its speed curve, which is usually sinusoidal with a maximum speed ator near to its passage through the forming die. This prior art packagingmachinery is illustrated, for example, in applicant's U.S. Pat. No.3,260,174 issued Jul. 12, 1966. Except for refinements in a few of themechanical drive components, there have been no significant changes inthis basic drive and control system in the last 25 years.
OBJECTS OF THE INVENTION
One object of the invention is to provide improved drive means for theplunger allowing for a wide variety in the motion of the plunger, such asits stroke, speed curve, or interrelated timing, to be preset.
Another object is to provide improved blank feeder means also allowing forvariety in the motion and very accurate positioning of the blank over theforming die.
A further object is to provide programmable control means for the plungerdrive means and the blank feeder means whereby their interrelated timingcan be adjusted to maximize speed of operation.
Yet another object is to provide improved conveyor drive means also subjectto programmable control for precise timing of propelling flights on theconveyor with formed cartons deposited from the die.
A still further object is to provide product delivery means likewisesubject to programmable control, by means of a product/carton sensor notonly for precise timing of product into a carton, but also to withholdproduct in the event that a carton is missing from the sequence on theconveyor.
Likewise, an object of the invention is also to provide a product sensormeans associated with the conveyor so that a carton blank is not fed tothe die in the event that no product will be available to be deliveredinto the said carton.
Additional objects, advantages, and other novel features of the inventionwill be set forth in part in the description that follows and in part willbecome apparent to those skilled in the art upon examination of thefollowing or may be learned with the practice of the invention. Theobjects and advantages of the invention may be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, a carton former comprises aforming die having carton blank supporting surfaces adjacent an upperentry end, a magazine for flat carton blanks, feeder means for extractinga leading blank from the magazine and depositing it on the supportingsurfaces of the forming die, a plunger reciprocally through the formingdie to push the blank through the die to form a carton, stripping means ata lower exit end of the forming die, a servo drive means for effectingreciprocation of the plunger, and a controller (such as a programmablelogic controller) coupled with the servo drive means for determining atleast the stroke and speed of the plunger.
Thus, the controller can be used to program the servo drive means so thatit effects a rapid approach of the plunger to a carton blank on thesupporting surfaces of the forming die, effects a rapid slowing of theplunger before contact with the carton blank, speeds up again as entryinto the forming die proceeds, maybe effecting a temporary stop or "hold"of the formed carton in the forming die to set its folds, and effects avery fast return of the plunger (after stripping of the formed carton fromit below the forming die) to bring the plunger back far enough above theforming die for feeding of the next carton blank from the magazine to theforming die.
The plunger is conveniently carried by the lower end of a vertical shaftslidably but non-rotatably mounted in a pair of spaced guides, and theupper end of the shaft may be connected to a hydraulic or pneumatic pistonor a linear motor adapted as the servo drive means, or a recirculatingball or roller screw on a rotatable shaft may be driven by a programmablereversible motor or by a stepping motor. To save on height, the shaft mayhave secured to it, a lateral arm intermediate the spaced guides and thelateral arm is also secured to a chain or gear-belt trained aroundsprockets, one of which is driven by a standard servo motor with anencoder/tachometer feedback, and the sprocket driven by the servo motor ispreferably on an axis parallel to but horizontally offset from the lowerof a pair of sprockets between which extends a vertical run of the chainor gear-belt to which the lateral arm is secured.
The carton blank feeder means preferably comprises at least one suction cup(but preferably two or more suction cups) carried by an arm secured on ahorizontal shaft enabling the suction cup (or cups) to be swung betweenthe magazine and a position just above the supporting surfaces of theforming die, and a servo motor for oscillating the shaft, for example,through a chain or gear-belt and sprockets, the servo motor also beingcoupled with the controller, to enable the timing and extent of swing ofthe suction cup (or cups) to be optimized.
A programmable logic controller preferably has an operator controlinterface including a control and display panel enabling ready adjustmentof plunger stroke and speed, blank feeder swing and timing, and conveyoroperation to be effected and displayed.
The conveyor system may comprise one or more conveyor chains with flightsfor propelling the formed cartons in succession to product delivery meansof one or more production machines and carton closing means, and eachconveyor chain may be driven by a servo motor coupled to the controller,to enable the timing of the flights past the lower exit end of the foldingdies in coordination with the stripping of formed cartons from theplunger.
Alternatively, the conveyor system may comprise one or more flight-lessbelts, and each belt may be driven by a servo motor coupled to thecontroller. Programmable control may also be used with walking beamconveyors, and also with starwheels and "pick-and-place" mechanismsassociated with conveyors.
Product delivery means may be subject to programmable control by thecontroller, both to effect timing of product delivery with formed cartonspassing along the conveyor system, and also preferably to withhold productin the event that a carton is missing from the sequence on the conveyorsystem, in which case carton detector means is provided at an intermediateposition along the conveyor system and is coupled to the controller.
Likewise, detector means for product is preferably provided in advance ofthe product delivery means and coupled to the controller, to ensure that acarton blank is not fed to the forming die in the event that no productwill be available to be delivered into the said carton.
Still other objects of the present invention will become readily apparentto those skilled in this art from the following description wherein thereis shown and described a preferred embodiment of this invention, simply byway of illustration of one of the modes (and alternative embodiments) bestsuited to carry out the invention. As it will be realized, the inventionis capable of other different embodiments, and its several details arecapable of modifications in various, obvious aspects all without departingfrom the invention. Accordingly, the drawings and descriptions will beregarded as illustrative in nature and not as restrictive.

We claim:
1. An apparatus for forming cartons from flat paperboard blanks comprising:
a die for receiving the blank;
a reciprocating plunger to push said blank through said die to form saidcarton;
servo drive means including a variable speed electric motor for saidplunger; and
programmable control means for operating said servo drive means;
whereby the full operating motion of said plunger can be infinitely variedto fit the forming action desired.
2. The forming apparatus for cartons of claim 1 further comprising:
feeder means for feeding said blanks to the face of said die;
additional servo drive means including a variable speed electric motor forsaid feeder means; and
said programmable control means operating said additional servo drivemeans;
whereby the full operating motion of said feeder means can be infinitelyvaried to fit the forming action desired.
3. The forming apparatus for cartons of claim 1 further comprising:
conveyor means for receiving the cartons for additional processing;
additional servo drive means including a variable speed electric motor forsaid conveyor means; and
said programmable control means operating said additional servo drivemeans;
whereby the full operating motion of said conveyor means can be infinitelyvaried to fit the forming action desired.
4. The forming apparatus for cartons of claim 1 wherein said electric motorof the first mentioned servo drive means comprises a variable speed,electronic servo motor and said control means includes an electronicprogrammable logic controller.
5. The forming apparatus for cartons of claim 2 wherein said electric motorof the additional servo drive means for said feeder means comprises avariable speed, electronic servo motor and said control means includes anelectronic programmable logic controller.
6. The forming apparatus for cartons of claim 3 wherein said electric motorof the additional servo drive means for said conveyor means comprises avariable speed, electronic servo motor and said control means includes anelectronic programmable logic controller.
7. The forming apparatus for cartons to receive product from delivery meansof claim 1 wherein is further provided product sensor means for detectingproduct availability for said carton, said programmable control meansbeing operative to time the product into said carton.
8. The forming apparatus for cartons to receive product from delivery meansof claim 7 wherein is further provided carton sensor means for detectingthe availability of a formed carton on a conveyor means and forwithholding product when a carton is missing.
9. The forming apparatus for cartons to receive product from delivery meansof claim 1 wherein is further provided product sensor means for detectingproduct availability for said carton, said programmable control meansbeing operative to interrupt said blank feeding means when product isunavailable for delivery into said carton.
10. The forming apparatus for cartons of claim 1 further comprising:
an operator control interface for setting and displaying the controlparameters of said programmable control means.

BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of carton former in accordance with the invention, withassociated blank feeder means and conveyor, will now be described, by wayof example only, with reference to the accompanying diagrammatic drawings,in which:
FIG. 1 is a side elevation showing a carton blank having been extractedfrom the magazine and swung down into position over the forming die;
FIG. 2 corresponds to FIG. 1 but shows the plunger pushing the carton blankthrough the forming die;
FIG. 3 is a fragmentary part-sectional elevation taken from the lineIII--III in FIG. 2; and
FIG. 4 is a schematic diagram of the control circuit.
DETAILED DESCRIPTION OF THE INVENTION
In FIGS. 1 and 2, a forming die 10 has carton blank supporting surfaces 11adjacent an upper entry end 12, and carton stripping means 13 at a lowerexit end 14.
A plunger 15 is carried by the lower end of a vertical shaft 16 slidablybut non-rotatably mounted in a pair of spaced guides 17 for reciprocationthrough the forming die 10, a lateral arm 18 secured to the shaftintermediate the guides also being secured to a gear-belt 19 trainedaround sprockets 20, 21, 22, with the sprocket 20 horizontally offset fromthe sprocket 21 and driven by a standard electronic, infinitely variablespeed servo motor 23 with an encoder/tachometer feedback and which iscoupled to a programmable logic controller 24 (see also FIG. 4).
Referring to FIGS. 1-3, carton blank feeder means comprises a magazine 25for flat carton blanks, a pair of suction cups 26 carried by a frame 27 onan arm 28 secured on a horizontal shaft 29 enabling the suction cups to beswung from a position at the magazine (as shown in chain-dotted lines inFIG. 1 and in full line in FIG. 2) to a position (shown in full line inFIG. 1) just above the forming die 10, and a servo motor 30 foroscillating the shaft 29 through a gear-belt 31 and sprockets 32, 33; theservo motor 30 also being coupled to the programmable logic controller 24,for infinitely variable control to enable the timing and extent of swingof the suction cups 26 to be optimized.
The logic controller 24 can be programmed, as by input means including acontrol and display panel, preferably including a keyboard and CRT display(not shown), forming an operator control interface 34 provided for thecontroller, so that the servo motor 23 effects an infinitely variablemovement, such as a rapid approach of the plunger 15 to a carton blank 35on the supporting surfaces 11 of the forming die 10, then effects a rapidslowing of the plunger before contact with the carton blank, speeds upagain as entry into the forming die proceeds (as shown in FIG. 2), maybeeffecting a temporary stop or "hold" of formed carton 35X in the formingdie 10 to set its folds, and effects a very fast return of the plunger 15(after stripping of the formed carton from the plunger by the strippingmeans 13) to bring the plunger back far enough above the forming die forfeeding of the next carton blank from the magazine 25 to the forming die10.
Each formed carton 35X falls on to a conveyor 36 having propelling flights37 and driven by a servo motor 38 through a gear-belt 39 and sprockets 40,41, the servo motor 38 also being coupled to the programmable logiccontroller 24, to enable the infinitely variable timing of the flights 37past the lower exit end 14 of the forming die 10 to be coordinated withthe stripping of formed cartons 35X from the plunger 15.
The controller 24 preferably includes a microprocessor, such as an STDcompatible 16 bit base computer, Cubit Model 8600 with a servo motorcontroller card, such as a Tech 80, Model 4322 and amplifier, such as Imec400. The preferred compatible servo motor may be a Pacific Scientific RA6SENA-TD-ED-NV-02. As configured, the circuit is capable of controlling allfunctions and repeating all movements required for any desired plungermovement pattern and/or carton size that is entered into the memorythrough the keyboard of the control interface 34. By providing a centralcontroller 24 as described, there can be full coordination between allfunctions of blank feeding and plunger 15 operation; as well as, controlof the conveyor 36.
To provide a fuller description of the operation of the product/cartonsensing functions of the present invention, reference should now be madeto FIG. 4. The product delivery means 50, which may be fed by severalproduct processing machines (not shown) is controlled by logic controller24. The product sensor means 52, such as a photoelectric unit or aproximity unit (infra-red detector), detects product availability alongthe delivery means 50 in readiness for the next in-line carton 35X andtimes the product into said carton. In the event the next in-line carton35X is missing, a similar carton sensor means 54 feeds a signal to thecontroller 24 to withhold product being delivered by the delivery means50. When product is unavailable for delivery to a finished carton 53X, asdetermined by the sensor means 52, the blank feeding means is interrupted.According to these features, product is not only properly timed with thecartons 53X, but cartons are advantageously not formed and wasted whenproduct is unavailable for filling. If a carton 53X is formed, but removedfrom the conveyor 36 before reaching the product delivery means 50, theproduct is withheld to prevent spillage.
The outstanding results and advantages of the present combination inventionover the prior art cited should now be apparent. The carton formingapparatus, and related control circuit (see FIG. 4), extends thecapability of such forming operations by increased speed and better cartoncontrol, as well as higher efficiency. The servo motors 23, 30, 38 areprecisely controlled by signals generated from programmed data supplied tothe programmable index controller 24 indicative of the particularrequirements for carton forming. These controlled movements are furtherprecisely coordinated with the product delivery. The use of servo motorseliminates a substantial number of mechanical actuators and linkageproviding attractive manufacturing cost savings. Furthermore, efficiencyand reliability are enhanced since the servo motors are very energyefficient and rugged in design.
Utilization of the servo motor 23 for driving the plunger 15 is of specialsignificance to allow programmed control of the carton forming function.By specifying the interval speed, acceleration and position of theplunger, better timing and control of the blank and improved forming ofthe carton is attained. This precise movement pattern of the plunger helpsto insure exactly the correct speed/acceleration profile at each point inthe cycle. Controlling of all motors 23, 30, 38 by the same programmableindex controller 24 adds an additional significant step to reach theoptimum speed and efficiency of the overall carton forming and packagingoperation.
The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Obvious modifications or variations are possible in light ofthe above teachings. The embodiment was chosen and described to providethe best illustration of the principles of the invention and its practicalapplication to thereby enable one of ordinary skill in the art to utilizethe invention in various embodiments and with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the invention be defined by the claims appended hereto.