US2785611A - Apparatus for heatsealing - Google Patents

Description

March 19, 1957 J. D. com-1 APPARATUS FOR HEATSEALING 7 Sheets-Sheet 1 Filed June 18, 1954 Flli March 19, 1957 J. o. CONTI APPARATUS FOR HEATSEALING 7 Sheets-Sheet 2 Filed June 18, 1954 March 19, 1957 J. D. CONTl APPARATUS FOR HEATSEALING 7 She'ets-Sheet 3 Filed June 18, 195 4 WA R March 19, 1957 J. D. coNTl APPARATUS FOR HEATSEALING 7 Sheets-Sheet 4 Filed June l8 1954 March 19, 1957 J. D. CONTl 2,785,611

APPARATUS FOR HEATSEALING Filed June 18, 1954 7 Sheets-Sheet 5 March 19, 1957 J. D. coN'n APPARATUS FOR HEATSEALING 7 Sheets-Sheet 6 Filed June 18, 1954 7 Sheets-Sheet 7 Filed June 18, 1954 own oOhN

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m: ZOPPODw mhdw on E 5 52 .mu 6 mn M241 United States APPARATUS FOR HEATSEALING John D. Conti, Elkins Park, Pa., assignor to American Viscose Corporation, Philadelphia, Pa., a corporation of Delaware Application June 18, 1954, Serial No. 437,769

1 Claims. c1. 93-36-8) This invention relates to packaging apparatus and, more particularly, to a machine for folding and sealing the flaps of cardboard cartons.

The present invention is a continuation-in-part of my copending application Serial No. 223,629, filed April 28, 1951, now abandoned. The apparatus is particularly adapted to the sealing of cartons not only of cardboard but of related materials such as fiberboard, chipboard,

Figures 8-12 are fragmentary details illustrating progressively the action of the ram assembly of Figure 7;

Figure 13 is a schematic view showing the various electrical and hydraulic actuating controls; and

Figure 14 is a timing diagram for the various moving parts.

Generally, the objects of the present invention are accomplished by first coating the material to be sealed with a suitable thermoplastic coating composition by any known conventional method. A heated metal plate,

tongue, or shoe is brought in contact with the coated surfaces to be sealed, thus heating the thermoplastic coating. Suitable pressure may then be applied to complete the sealing operation. While the present invention is applicable to the sealing of any type material made from Y a thermoplastic substance or having a thermoplastic coat:

reinforced laminated cardboards and the like, the flaps of which are ordinarily sealed with a thermoplastic adhesive material. Prior practice has generally employed a liquid adhesive for carton flap sealing. Such adhesive has ing on the surface thereof, for simplicity the invention will be illustrated and described as it is generally applicable to the sealing of shipping containers or cartons, such as those made from cardboard and the like.

The fiat carton blanks with only the sides sealed are individually fed to a sealing station where they are opened up or squared by means of a pivoting gate supplied with suction cups. While oppositely moving pressure heads or rams are directed towards one end of the squared carton,

' a pair of heated blades fold the inside flaps to their sealed the objection that it frequently does not set up fast enough to'enable satisfactory use with high speed carton forming or filling machines.

Various thermoplastic type materials are used as adhee sives and are usually employed as a coating on .the surfaces or areas to be sealed. Sealing is accomplished by theapplication of heat and pressure to the oppositesurface to which the thermoplastic coating is applied. For

thin-materials, such as sheets of regenerated cellulose employed in making bags, this procedure is satisfactory and sealing is accomplished quickly. However, in the case of cardboard, and the like, such as employed in formingcartons, a longer time is required for the heat to penetrate the cardboard, etc. and soften the thermoplastic coating on the other surface sufficiently to give a good strong seal. The time required for such heat penetration is excessive when dealing with high-speed automatic carton-forming or set-up machines. 1

It is a general object of the present invention to pro-- vi'de an apparatus for heat-sealing thick thermoplastic t coated materials quickly and efficiently so as to produce a strong seal in a minimum amount of time.

'It is another. object of the invention to provide an apparatus for heat sealing thermoplastic coated 'carton flaps in such a manner that the same maybe employedin or in conjunction with high-speed automatic cartonforming machines.

It is a further object of the invention to provide a new f apparatus for heat-sealing thermoplastic films or thermoplastic coated materials.

Further objects will be apparent from the specification and drawings. in which: t

Figure 1 is a side view of a carton-sealing machine constructed in accordance with the present invention partly-sectioned and with other parts broken away for clarity; a

Figure 2 is a top view of the structure of Figure 1;

Figure? is an end view of the structure of Figure l; 7. Figure 4 is anenlarged fragmentary detail of one of the heating flap folders;

Figure 5 is a' side view of the structure of FigureA, Figure 6 is anenlarged sectional detail as seen -at Figure 7 is a perspective showing the horizontal-ll ap"-- VI'VI of Figure 4; Y

folding ram assembly and pressure plate;

position againstone of the rams, whereupon the other ram foldsjthe outside flaps over the heated blades and presses theifiaps together sufiiciently. long to effect a heating of Before final sealing pressure is applied, the pressure on the outside ram is removed for a time s'ufiiciently long to permit withdrawal of the hot blades, whereupon the outside ram is re-actuated to comtheadhesive on the flaps.

press .the flaps against the inner ram and complete the seal.

sequentially without interruption, the unsealed cartons being conveyed along a path to the sealing position one after another. The apparatus, hereinafter described in detail, is capable of sealing cartons of varying sizes. In addition, the method and apparatus may be employed to seal cartons which have already been packed.

Referring now more particularly to the drawings, a pre ferred-form of the apparatus comprises a generally horizontal feed tablel assembly 20 comprising a stationary l hopper 21 in which flat carton blanks C are loaded. The feed table assembly is supported on a suitable framework including posts or columns 22, 22. Individual cartons are withdrawn from the bottom of the carton stack in hopper T 21 by means of a reciprocating plate 23 actuated back;- and forth across the table by means of a fluid cylinder 24, which is connected to a bracket 25 on plate 23 through a piston rod 26. "The folded carton blanks are advanced to a set-up station on table 30 as shown in Figures 1 and 2. This table is provided with one or more suction cups 31 and 32 to retain the bottom of the carton on table 30 in proper position while the carton is opened. Withthe flat carton blank in proper place on table 30,

plate 23 is retracted and a pivoting plate or gate 33 swings down to the position shown in Figure 1 on top of the fiat carton. Gate 33 is likewise provided with a pair of suction cups or elements 34 and 35 so that when it is pivoted upwardly in a counterclockwise: direction, "as

receiver when the vacuum is released in the cups 34 and Patented Mar. 19, 1957-- All of the above operations take place continuously and 35. The actuating mechanism for gate 33 comprises a crank 40 journaled in a bracket 41 mounted on the frame-. work assembly. The crank arm is connected to gate 33 by means of a clip 42 to control the movement of gate 33 around hinge 43. The opposite end of the crank 40 is actuated by means of a rack 44 and a pinion 45whichare in turn controllable through a fluid pressure cylinder 46. A releasable latch 47 is mounted on post 48 of the framework to insure proper registry of gate 33 when in the set-up position, since it is important that the carton be substantially square to permit proper actuation of the other apparatus. a

When the carton C has been opened or squared to the position shown in Figures 1 and 3, a fluid cylinder assembly 49 is automatically controllable to advance a pressure head 50 into the open end of the carton from the left as seen in Figure 3'. During this operation the carton body is securely held in place by means of the suction cups 31, 32 and 34, 35. Simultaneously, the pressure head 51 is advanced by cylinder 52 mounted on framework 53 to slightly open the vertical carton flaps 54 and 54. This action is shown clearly in- Figure 10. With the vertical flaps slightly sprung outwardly, it is then possible to fold or bend the horizontal inner flaps 56, 56 to their sealed positions without danger of interference from the edges of the side flaps. For this purpose, I use a pair of heated blade assemblies 57, 58 which are respectively mounted and controlled by blade housings 59 and 60. The upper housing 59 is pivotally supported on cross frame members 61 and'62, whereas the lower blade assembly is mounted in trunnions. 63, 63.

Referring now to Figures 4-6, animportant feature.

of the invention resides in the provision of the heated blades andtheir associated structure. The blade housings are alike so that a description of the upper housing such, for example, as shown in Figure 4 will suflice for both. The blade proper 70 is movable into and out. ofv the housing 59 to enable it to be'heated and also to provide for the flap turning function. The blade extends inside the housing in a generally bifurcated manner having guide arms 70a and 701) which are carried in rollers 71, 71. A piston rod 72 is secured to the blade 70 between. arms 70a and 70b, and the opposite end of the piston rod is actuated by a conventional fluidpressure cylinder 73. blade itself is capable of vertical reciprocal movement when actuated by cylinder 73. Piston rod-72 carries a roller75 which extends through: a slot/7.6 in the housing 59. This roller runs along a track 77 (Figures 1 and 3) whichiis suitably supported by brackets and cross. members 78 and 79 secured to posts 80 and 81.

Housing 59, as noted above, is pivoted. in cross members 61 and 62 by hearings or trunnions 85,, 85. A spring 8.6 biases the housing so that the roller 75- is. maintained in spring-loaded, contact with the track 77. Whentheblade 70 is extended, it will be noted that the downwardor upward travel, as the case may be, is substantially in a straight line for a short distance. This is to start the bending of the inner flaps; 56, 56of the'carton at a point. substantially spaced. from their bend line.,

However, as the blade continuesto advance, track 77 curves towards the blade housing so that the housing; pivots on bearings 85, 85 to turn the flap through an:

arc of substantially 90.

The housings- 59 and 60 are provided with side members 90, 91. in which the rollers 71 are journaled.. Four. heating elements 92, 92 are suspended from. the housing cover 93 as shown in Figures 4 and 6. Suitable insulation 94, 94 reduces heat. dissipation from. heaters.92,, 9 2:. Also, I provide a pair of spring-loaded scrapers 95",; 95- to.- remove any adhesive or other matter which might be, retained on the blade and thus-causesticking; Theconstruction of both the upper and: lowerblade. housings isidentical, and, therefore, duplicateadescription. is: believedto be unnecessary; The reference numerals for In this way, it will bev apparent that they the lower housing 60 are used for corresponding parts but .withprimed numbers. that the heated blade flap folders may be used horizontally as well as vertically as shown.

The back-up ram 50 is mounted on a shaft or piston rod which is actuated by fluid cylinder 49. The ram head or pressure plate-50 is substantially the same configuration as the hollow cross-sectional area of carton 'C, and thisassemblyis supported in framework 101 in alignment with the open end of the squared cartons C. As soon as the carton is squared, ram head 50 advances into the carton, until it has substantially reachedv a fully extended position in which the forward face of the ram is approximately in line with the bend linesin the opposite end of the carton. As. noted previously, the carton is maintained in accurate registration by means of the suction cups in the gate and the table.

The opposite pressure ram head 51 serves a dual purpose in that it not only controls. the flaps before they areheated .but it also applies final sealing pressure. Re ferring to Figures 7-12, ram head 51. comprises a pressureplate 102 having attached on its face a pair of arcuate spring. arms-103'and 104. The extremities of. these arms. are provided with small springs 105 and 106 hav-' ing' a plateacross the U-shaped portion of each spring. After the'carton is positioned at the set-up station and squared by means of gate 33, cylinder 52 is energized to advance the ram. head 51 and its associated Spring structure. Figure 8 illustratesthe position of theram head and structure just before making contact with the carton flaps. Figure 9 shows initial engagement betweenthe- flat springs 103 and 104 and the side' carton flaps 54, 54. Further forward movement of theram 51 opensthe carton flaps 54,, 54 slightly as shown. in Figures 9 andlO, thus insuring that the upper flaps 56, 56 clear the edgesv of the side flaps when folded inwardly. As

to advance and'in so doing the flaps 54, 54 slide off of or out of engagement with the springs; 105, 106.

Figure 11. shows oneof the sideflaps after it has become disengaged fromthespring105. Continuedadvancing of the head. 51. folds the side flaps. against the hot blade 70-and compresses both the inner .and outer flaps against the. blade through the cooperation of ram 50 until the adhesive on. the flaps is adequately heated. The pressure on head. 51' is then momentarily released so that bothblades-70 and. 70 can. be withdrawn from betweenthe flaps. Pressure is. then. reapplied. to .head 51 to press the flaps against each other andcomplete the pressure seal, whereupon both the rams. 50..and 51 are retracted to permit the carton to be removed from the set-up station by means of. gate 33'.

In Figures 8-12, I have illustrated only. one sideof the ram: head 51 comprising plate 102, springs 103,. and 105. It will be understood that the opposite side of the ramhead assembly operates in an identical manner so. that the description with regard to spring 105 applies equally to spring 106.

A more detailed description of the actuating and coordinating mechanism for the various sub-assemblies described above will be apparent from a reference to Figures"13- and 14in which the timing sequence is more clearly shown. The" hydraulic system shown in full lines? in Figure 13 comprises a pump 110 connected to'a fluid sup-- ply reservoir 111-. Both fluid cylinders 73 and 73"a're controlled by means of a solenoid-actuated valve assembly 112. Cylinder 52 is controlled by 11163118101 a similar solenoid actuated valve 113 as areflui-d: cylinders 24 and Also, it will be understood mam 46 by. means of valves 114 and 115 respectively. The gate. stop latch 47 is electrically controlled as will be more fully described hereinafter, and the stop latch 116 for ram head 51 is likewise electrically controlled. The table suction elements 31 and 32 are controlled through solenoid-actuated valve 117, and the gate suction elements 34' and 35 are similarly controlled through a solenoid valve 118. The main suction supply conduit 120 connects a source of low pressure air or fluid (not shown) to the various suction elements 31, 32, 34, 35 by means of conduits 121 and 122. The back-up ram actuating cylinder is controlled similarly to cylinders 24, 46 and 52 through a solenoid-actuated hydraulic valve 125.

The timing mechanism for operating all the various moving parts of the machine, either directly through electrical mechanism or indirectly through solenoid-actuated fluid valves, comprises a timing cylinder or drum 130 journaled at 131, 132 and driven at a slow constant speed by motor 133. Current from a power source 134 is carried through conductor and brush 135 to a common segment 136 on the drum 130. Segment 136 is connected to the various separate segments S, S on the periphery of the drum so that the individual circuits are completed when contact occurs between the segments S, S and brushes B, B which are in turn connected to the various solenoid windings described above. The construction of such solenoids and solenoid-actuated valves is well-known in the art and formsno part of the presentinvention. Also, it will be understood that I have chosen to describe and illustrate a timing mechanism capable of providing the desired sequential operation of the various elements of the machine. Any other means for accomplishing this result may, of course, be employed within the scope of the invention. Since the timing of the various elements is critical, however, a chart has been prepared to indicate how they are cooperatively arranged to accomplish the desired result. The abscissae in Figure 14 represent degrees of rotation of cylinder 130; and when adjusted to handle a complete carton in 15 seconds, the relative time at which each operation takes place can be determined directly from the scale at the top of the graph.

At the indicated starting position of cylinder 130 shown as zero degrees on the graph, the gate suction, controlled by valve 118, is operative to hold the carton on the gate preparatory to being discharged therefrom. At this point cylinder 24 is actuated by closing of the contacts associated with the solenoid in valve 114. This in turn moves one flat carton blank from the bottom of the stack in hopper 21 to the folding station on table 30. Meanwhile, the gate suction has been closed to permit the carton on the gate to fall onto chute 36. At about 40 the gate 33 is turned in a clockwise direction, as seen in Figure 1, by retraction of rack 44 within cylinder 46. This positions the gate on top of the folded carton blank which has just been delivered to table 30. At about 67 both the table suction and the gate suction are applied by energization of valves 117 and 118. With suction still applied, valve 115 is de-energized at 90 so that rack 44 is expelled from cylinder 46. However, the gate 33 remains in a vertical position since it is held by latch 47. It will be under' stood in this connection that the latch permits clockwise rotation of the gate but will not permit the gate to pass when turned in a counterclockwise direction until the latch is released. At about 123 ram heads 50 and 51 are both actuated. Ram 50 advances into the carton until it is approximately opposite the bend lines for the flaps at the opposite end. Ram head 51 continues to advance until it is held by latch 116. During this portion of its travel, it has served to spread the vertical outer carton flaps 54 and 54 as described previously. At about 150 C. cylinders 73 and 73' are energized to fold the inner flaps against ram head 50. When these have been sufiiciently folded, the latch 116 for ram head 51 is release-d at 180, thus permitting ram head 51 to continue its advance and press the flaps against the heated blades 70 and 70'. At

atabout 275. This advances ram head 51 against the folded carton flaps and squeezes them between the plate 102 and the ram head 50 to pressure seal the flaps. At

about 330 contact for both rani valves is opened so that they retract to their initial positions. Then the table suction is removed by opening of the circuit to table suction valve 117; and, simultaneously, latch 47 is released, thus permitting the gate with gate suction applied to pivot to the discharge position shown at 33!) in Figure 1. This completes the operating cycle of the apparatus.

One of the important features of the present invention is the bringing of a heated element into direct contact with the thermoplastic coating, heating the coating quickly and then withdrawing the heated element and then applying pressure to the material to effect the seal. The seals thus produced are uniform and strong and scaling is accomplished quickly without the necessity of having to heat the coating through the base material to which it is applied which is time consuming.

It is to be noted that the sealing shoes or tongues can be shaped to seal or heat any desired area leaving unsealed In addition, the thermoplastic coating may be: applied to any surfaces for use in easy opening or other purposes.

desired area; Packages or cartonssealed in-accordance with the present invention are immediately suitable for" handling since no glues or liquid adhesives are employed which require time for drying. It is this applcation that makes the present invention particularly advantageous for high-speed automatic set-up box or carton machinery since the seal is made almost instantaneously.

By means of the present invention, it is possible to seal several cartons per minute and, in addition, all messy glue pots, glue applicators, metal stitching machines, etc. are eliminated. The thermoplastic material or coating may be put on the carton flaps when the carton blanks are formed by the manufacturer.

When attempts were made to pull apart the seals made in accordance with the present invention, the cardboard tore rather than the seal or bond breaking loose. Seals were checked under 92% relative humidity conditions and found to be excellent in all respects. It will be apparent from the description of the present method and apparatus that the invention is easily adapted for sealing the open end of the carton after insertion, mechanical or otherwise, of the material to be packed therein. Numerous other advantages of the present invention will be apparent to those skilled in the art.

As many possible embodiments may be made of the mechanical features of the present invention and as the process may be varied in various aspects, all without departing from the spirit and scope of the invention, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. An apparatus for closing and sealing a carton end comprising means for guiding a carton having flaps extending endwise from its side walls into a heat-sealing station, means on opposite sides of the carton at the sealing station for folding the flaps inward into closing relationship, said folding means comprising a thin bladelike member reciprocable from an initial position adjacent the outer side of each of a pair of opposite flaps extending endwise from a side wall of a carton disposed in the sealing station to a position wherein one of its surfaces is in contact with the outermost surface of a folded inner flap, and second means for folding another pair of opposite outer flaps against the blade-like members, means for heating the members in their initial position, means for reciprocating the members away from said heating position, and means for pressing the pairs of folded flaps together after the members are returned to their initial position.

2; Apparatus in accordance with claim 1 in which the second folding means includes at least one reciprocable ram.

3. In box closing apparatus, the combination which comprises a box closing station, means for sup lying boxes having unfolded end flaps to said station, a pair of oppositely disposed heating tongues positioned in line with the station, means for advancing the tongues into the station to fold two inner opposite flaps of a box and to heat the outer sealing surface of said flaps, means for heating said tongues when in a retracted position, means for advancing and retracting the tongues in timed relation with the operation of said box supplying means, an outer flap folding element mounted to fold a pair of outer box flaps over thetinner flaps and the tongues, saidflap foldingelement being positioned to operate in a direction at right angles to the direction of movement of the tongues, means for operating said flap folding element in timed relation to the movement of the tongues, a plunger positioned to move into the box to back up the flap folding elements thereby pressing the inner and outer box flaps together, and means for actuating the plunger in timed relation to the flap folding elements from a retracted position to an advanced position on the inside of the folded box flaps,

4. Apparatus in accordance with claim 3 in which the tonguesv are retracted into a housing.

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5. Apparatus in accordance with claim 4 having at,

6. Apparatus in accordance with claim 5 in which the tongue is a relatively thin elongated flat blade.

7. In box closing apparatus, the combination which comprises a box closing station, means for supplying boxes having unfolded end flaps to' said station, a" pair of oppositely disposed thin flat heating tongues-positioned in line with the station, a housing for each of said tongues into which they are retracted, means for advancing the tongues into the station to fold two inner opposite flaps of a box and to heat the outer sealing surface of said flaps, heating means in the housing for said tongues, an outer flap folding elementmounted to" fold a pair of outer box flaps over the inner flaps and thetongues, said flap folding element being positioned to operate in a direction at right angles to the direction of movement ofthe tongues, and means for operating said flap folding element in timed relation to the movement of the tongues.

Evans et a1. Mart-29, 1927 Kirk Aug. 5, 1947

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