US3438175A - Automatic packaging apparatus - Google Patents

Description

April 5, 1969 J. A. HAMILTON ETAL 3,438,175

AUTOMAT IO PACKAGING APPARATUS Filed Feb. 1 1965 7 Sheet I off-2 LlNE qr MOVEMENT Ant/LOWE .Faro l'l: tgseph Leitner A ril 15, 1969 J. A. HAMILTON ETAL AUTOMATIC PACKAGING APPARATUS Sheet Filed Feb. 1, 1965 United States Patent O 3,438,175 AUTOMATIC PACKAGING APPARATUS Joel A. Hamilton, Clifton, Anthony E. Faro, Jr., Wayne,

and Joseph Leitner, Paterson, N.J., assignors to Mahafly & Harder Engineering Company, Totowa, NJ.

Filed Feb. 1, 1965, Ser. No. 429,458 Int. Cl. B6511 67/00 US. Cl. 53-112 11 Claims ABSTRACT OF THE DISCLOSURE An automatic packaging machine of the type including a plurality of separate trays individually mounted on conveyor chains for movement around a closed loop past a number of packaging stations, the trays being arranged to receive plastic film stretched into the tray cavities to form package cups, rigid paperboard tops being sealed over such cups to make complete containers which are evacuated through an opening in a flange of the cup; and wherein means are provided to pre-heat the tops in the region thereof adjacent the evacuation opening so that the board can quickly be sealed to the flange at that region after evacuation; and wherein the trays also are provided with clamps operable to grip the packaging material below the surface of the tray, thereby to permit the rigid tops to lay flat across the trays; these clamps further being pivotally mounted to produce a lateral outward displacement when actuated, thereby to simplify insertion of the packaging material.

This invention relates to automatic packaging apparatus. More particularly, this invention relates to such apparatus for making packages wherein one side of the package comprises a relatively stiff or semi-rigid board member, e.g. a flat laminated member formed of paperboard combined with one or more layers or coatings of plastic or lacquer.

As shown in US. Patents 3,061,984 and 3,125,838, packaging apparatus has been provided comprising an endless train of receptacles travelling past a series of packaging stations arranged to produce in the receptacles packages made from two continuous sheets of flexible plastic film. One of these sheets is vacuum formed down into the cavities of the receptacles to make cup-shaped package sections which are loaded with the products. The other sheet then is placed across the open mouth of the formed package section and is heat-sealed thereto around the marginal edges of the receptacles so as to make airtight containers. Copending application Ser. No. 213,705, filed by Mahaify et al. on July 31, 1962, now Patent No. 3,180,066, and copending application Ser. No. 368,926, filed by Mahaify et al. on May 20, 1964, now Patent No. 3,343,332, show still further developments in packaging apparatus of that general class.

The design of similar automatic packaging apparatus for making packages which include semi-rigid boards, i.e. so-called board-backed packages, has presented a number of difficult problems. One of the most important of these problems results from the fact that the board can not readily be heat-sealed to the flexible plastic film by conventional arrangements wherein the heat is applied through the backing member. In such arrangements, the relatively large heat capacity of the board prevented sufficient heat transfer to produce an effective seal within the time limits imposed by the operating speed of the machine. The problem could not be solved simply by applying the heat from the film side of the package, due to other complexities.

Apparatus as disclosed in the above patents includes both a preliminary seal station and a final seal station. In the first of these stations, the two facingplastic 3,438,175 Patented Apr. 15, 1969 "ice sheets of the package are partially sealed together around their outer peripheries while leaving an unsealed area at the evacuation opening previously made by slitting the vacuum-formed plastic film. At the final seal station the package first is evacuated through the slit, and then the two sheets are sealed together around the opening to complete the package. These operations are carried out by a single packaging head which extends over both stations and moves vertically into and out of operating position.

The preliminary seal operation does not present any significant heat transfer problem when making a package having a backing board, because the entire cycle time (normally about one second for each packaging operation) is available for completing the heat seal through the board, and this oridinarily is quite sufficient. However, in the final seal station, about of the cycle time is required for evacuation of the package, leaving only about 0.1 second to seal the backing board and the film together around the evacuation opening. As a practical matter, this latter time is too short to provide sufiicient heat through the backing board to complete the final seal, utilizing conventional techniques.

In accordance with the present invention, this problem has been solved by preheating the final seal region of the backing board while maintaining that part of the board out of contact with the thin plastic film to which it ultimately is to be sealed. In the specific embodiment disclosed herein, the heated sealing bars at the preliminary seal station extend over the region of the evacuation opening, but are relieved in a gradual arch-shaped configuration so that the bars in this region do not come down in contact with the backing board when it is lying flat against the plastic film. When the packaging head is in operating position, air under pressure is admitted through the evacuation opening, and serves to force the backing board up, in a somewhat bowed configuration, against the arched sealing bars. Thus the board is heated in the region of the evacuation port during the preliminary sealing operation, but is held out of sealing contact with the fiat film secured to the receptacle therebeneath.

When the preliminary sealing operation is completed, the receptacle is shifted to the adjacent final seal station. There the package is evacuated in the usual way and the heated final seal bar is brought down against the backing board to press it firmly into engagement with the plastic film around the evacuation opening. The heat already stored in this section of the board from the preliminary seal operation, added to the heat and pressure from the final seal bar, is sufiicient to complete the final sealing of the board around the evacuation opening in the very limited time available for this operation.

Accordingly, it is an object of this invention to provide packaging apparatus and methods superior to those available heretofore. A more specific object is to provide apparatus and methods especially suited for making boardbacked packages. Other objects, aspects and advantages of the invention will in part be pointed out in, and in part apparent from, the following description considered together with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a portion of a packaging machine embodying the present invention;

FIGURE 2 is a section taken along line 22 of FIG- URE 1, showing both the preliminary and final seal stations;

FIGURE 3 is a section taken along line 3-3 of FIG- 2, showing the backing board pressed up against the arched heating bars in the preliminary seal station; and

FIGURE 4 is a detail of the recessed film clamp.

The apparatus shown in FIGURE 1 is a portion of a complete vacuum packaging machine of the general type shown in the above copending application Ser. No. 368,- 926. This machine comprises a large number of packaging dies in the form of trays 10, only two of which are shown. These trays are connected together in an endless loop and are driven with an intermittent indexing motion past a series of packaging stations. Each tray contains the usual two side-by-side package-forming cavities.

At one of the packaging stations preceding those shown in FIGURE 1, a thin film of plastic packaging material 12 is vacuum-formed down into the cavities of the trays to form cup-shaped package sections which are loaded with the products to be packaged. Thereafter, a semirigid backing board 14 is placed on top of each tray, over the open mouth of the package section, and the tray is advanced to the preliminary seal station generally indicated in FIGURE 1 at 16.

Extending over this preliminary seal station 16 and the adjacent final seal station 18 is a packaging head 20. This head is shown in its tilted-back position simply to provide a better view of its construction. During normal operation of the machine, head 20 will be in a horizontal position, as shown in FIGURES 2 and 3, and is arranged tomove vertically a small distance in synchronism with the motion of the trays 10, to provide clearance for the advance of the trays between each cycle of operations.

The preliminary seal section of head 20 comprises an electrically heated bar element generally indicated at 22. The peripheral portion 24 of this element is aligned with the outer edges of the trays 10 and, as in prior machines, is planar so that it can seat down against the fiat board 14 to establish a marginal seal of the board to the plastic film 12. Heating element 22 additionally includes an arched portion 26 (see also FIGURE 2) bridged between the opposite planar portions 24 and overlying the tray partition 10a (FIGURE 3) dividing the two side-by-side tray cavities.

When the tray 10 reaches the preliminary seal station 16, and the head 20 has been moved down into operating position, air under pressure (3 psi.) is admitted into the interior of the package. The air is applied through the evacuation opening 28 and the tray chamber 30 containing the web-lifter 32, the latter being provided as disclosed in the above US. patents to aid in the evacuation of the package when the tray reaches the final seal station.

The compressed air in the package presses the board 14 up against the gradually-relieved arched heater element 26 which in turn applies substantial heat to the contacted section of the board while the peripheral heater element 24 seals the outer edges of the board to the corresponding regions of the film. During this operation, the film remains secured in position on the tray, and thus the heat transferred to the board by arched heater element 26 does not efiect any sealing of the film and board in that region. Plates 34 are provided to limit the upward movement of the board resulting from the compressed arr.

After the preliminary seal is complete, the head 20 is shifted up a small distance and the tray containing the partially sealed package is advanced to the final seal station 18. There the head 20 again comes down, and the web-lifter 32 is shifted up (by known means not shown) so as to arch the board 14 above the evacuation opening 28 and make possible a relatively rapid evacuation of the package. After evacuation (about 0.9 second), the weblifter drops down and the final seal bar 36 (FIGURE 1) is pressed down onto the board in the region around the evacuation opening. This heat and pressure, added to the heat already stored in the board by the heater element 26, is sufficient to complete the seal within the very short time (about 0.1 second) remaining in the machine cycle. Thus two fully sealed, side-by-side packages are formed in the two tray cavities, and the machine thereafter advances the tray to conduct other necessary operations, i.e. to remove the packages, fold under the ends of the board 14 along the outboard score notches, and separate the packages along the center score notches.

While the package is being evacuated in the final seal station, the packaging head chamber 38 (FIGURE 2) above the board 14 also is evacuated, to tend to equalize the pressures on opposite sides of the board. It is difficult to keep this chamber pressure exactly equal to the internal package presssure, and at times the chamber pressure will decrease more rapidly than desired. When this occurs, there is some danger that the board would be forced up, tending to tear the previously-formed preliminary seals, or to press the board against the chamber roof with suificient force to cause undesirable deformities. To avoid these results, vacuum is introduced into chamber 38 through a port 40 which is centrally located in a position where the board can engage the open mouth of the port if the board is pressed up too far. In that event, the board closes the port and, with a self-valving action, reduces the rate of evacuation of the chamber so as to restore pressure equilibrium with respect to the interior of the package.

As shown particularly in FIGURE 3, each tray 10 is provided with recessed clamps 42 which hold the formed plastic film 12 in place. This recessed arrangement is especially advantageous because it permits the semi-rigid boards 14 to lie fiat across the entire tray, without interference from the protruding clamp mechanisms commonly used in prior machines. In addition, these clamps 42 are arranged so that they open with a swinging movement, pivoting about the outboard end 42a when moved up by the springloaded actuator 44 at the preceding filmclamping station, illustrated at FIGURE 4. C-shaped member 46 at that station holds down the end 42a, and also serves to guide the film 12 in under the raised clamp.

Thus it will be apparent that the free end 42b of the clamp moves up a distance approximately twice that of the actuator 44, so as to provide a larger opening to receive the film 12 than in previous arrangements. In addition, this free end moves laterally away from the tray cavities, providing substantial clearance for inserting the film. This avoids the need for complicated devices for feeding the film 12 in under the clamp, such as mechanical tuckers. It also makes the machine more readily usable with preformed cups typically made of heavy plastic and thus difficult to bend into place under conventional clamps.

The planar heater elements 24 include rearwardly extending cars 48 which overlap the packaging station immediately preceding the preliminary seal station 16. These ears serve to tack-seal the board 14 to the plastic film 12 in that preceding station for the purpose of maintaining the board in registry with the rest of the package while the tray is being advanced into the preliminary seal station.

At the station just preceding the above-described tackseal station, the boards 14 are placed on the trays 10 from a magazine holding a vertical stack of the boards in horizontal disposition above the packaging machine and aligned with the trays passing beneath.The bottom board is held by two supports, one at the front and one at the rear. Both supports extend at right angles to the direction of tray movement, i.e. along the long sides of the boards. The rear support consists of a bar having a rectangular cross-section the long dimension of which normally is tilted towards the rear of the machine at an angle of about 30 or 40 degrees with respect to vertical, this sloping disposition providing an angular flat surface on which the bottom board of the stack rests.

This rear support bar is rotatably mounted about a longitudinal axis extending along its lower edge, i.e. below the bottom board. When a board is to be taken from the stack, the bar is rotated forwardly so that the sloping surface thereof engages the rear edges of the bottom four or five boards, tending to bend the boards somewhat to effect a slight separation. At the same time, a picker, comprising a pair of rubber vacuum cups, is rotated up about a transverse axis into contact with the bottom board and suction is applied so as to grip that board. The rotation is carried sufliciently far towards the forward end of the machine that the bottom board is bowed slightly downwardly away from the next adjacent board, tending to pull the bottom board away from the rear support bar, now nearly in upright position. The picker then rotates in reverse direction, i.e. clockwise as seen from the side shown in FIGURE 2, pulling the bottom board from the stack, and swinging that card down 90 degrees to a vertical position below the magazine and half-way between the tack-seal station and the board-loading station. From that position, the board is swung downwardly another 90 degrees by a second vacuum-cup picker which deposits the board exactly in registry on the tray at the boardloading station. As the tray is advanced from that station, the loaded board is held in registry with the tray by roller means pressing down on the top of the board until the tray reaches the tack-seal station previously described. The roller pressure need not be very great because there normally is a reasonably high friction between the board and the film due to the nature of the plastic coating material used.

After the packages have been evacuated and completed under head 20, they are advanced to a position where the trays are vertically disposed at the front end of the endless chain of trays. There another vacuum-cup picker removes the packages and swings them 90 degrees into horizontal position, but with the boards 14 on the bottom. These packages are placed on a flighted conveyor which carries them horizontally past a pair of stationary deflectors disposed at the edges of the conveyor and arranged to engage and bend the side tabs of the boards (along the score notches) up to a vertical position. Thereupon, a pair of corresponding side flippers, each consisting of a member normally in upright position, are rotated inwardly towards the package from respective sides of the conveyor to engage the now vertical board tabs and bend them a further 90 degrees to a horizontal position. The packages then are advanced still further to a position where the folded-over side tabs are heat sealed to the main part of the board. Finally, the two side-by-side packages are slit apart for shipment to the customer.

Although a specific preferred embodiment of the invention has been set forth in detail, it is desired to emphasize that this is not intended to be exhaustive or necessarily limitative; on the contrary, the showing herein is for the purpose of illustrating the invention and thus enable others skilled in the art to adapt the invention in such ways as meet the requirements of particular applications, it being understood that various modifications may be made Without departing from the scope of the invention as limited by the prior art.

What is claimed is:

1. Packaging apparatus of the type comprising a plurality of elements mounted in an endles loop for simultaneous movement around a closed path, said elements being arranged to carry around said closed path corresponding cup-shaped package sections on which various packaging operations are performed at selected stations along that path; said package sections being adapted to receive over the openings thereof tops of packaging material having a relatively high heat capacity and cooperable with said package sections to define complete containers; means at a second station to evacuate each container through an opening in said package section; final seal means operable after said evacuation operation to heat seal a limited portion of the top to the package section in the immediate region of the evacuation opening so as to block off the evacuation opening; and preliminary heating means operable before said final seal means to apply to and store in said top portion a sub stantial amount of heat while maintaining said top portion out of contact with said package section, thereby to permit said final sealing operation to be effected in a relatively short time period.

2. Apparatus as claimed in claim 1, wherein said preliminary heating means comprises a relieved heating element normally out of contact with said top when the latter is in flat condition, and means for pressing said top up against said heat element during a preliminary sealing operation, said top comprising a semi-rigid board memher.

3. Apparatus as claimed in claim 2, wherein said pressing means consists of air under pressure admitted into the container through the evacuation opening.

4. Apparatus as claimed in claim 1, wherein said final seal means and said preliminary heat means are carried by a single packaging head movable into and out of operating position and extending over two adjacent stations along said closed path, said preliminary heating means being at one of said stations and said final seal means being at the other.

5. Packaging apparatus of the type comprising a plurality of receiving elements mounted in an endless loop for simultaneous movement around a closed path, said elements being arranged to carry around said closed path corresponding cup-shaped package sections on which various packaging operations are performed at selected stations along that path; said package sections being adapted to receive over the openings thereof tops of packaging material to define complete containers; a packaging head at another of said stations adapted to seat against each container, said packaging head defining a closed chamber above the top of the container; means to evacuate each container through an opening beneath said top while the container is beneath said packaging head; the roof of said chamber being provided with a port to evacuate said chamber to tend to make the pressure thereof equal to the internal container pressure, said port comprising a tubular conduit means protruding down away from the chamber roof a short distance towards said top to define an open at least substantially planar mouth positioned centrally above said top to receive and be engaged by said top to close off the port if the chamber pressure drops so rapidly that the top tends to be forced up into a position where it can be damaged, the closing of said conduit means producing a self-valving action serving automatically to decrease the rate of chamber evacuation so as to equalize the pressures between said chamber and the interior of the container.

6. Packaging apparatus of the type having a plurality of trays mounted for simultaneous movement around a closed path, said trays comprising wall means including front and rear walls with side walls extending therebetween; said walls defining cavities adapted to receive package sections having flanges around the mouths thereof, said walls presenting at the tops thereof flange sealing surfaces forming a continuous planar surface extending around the tray cavities immediately adjacent thereto; said trays being provided with recesses outboard of the side wall sealing surfaces; each recess being formed, at a position closely adjacent the corresponding side wall flange sealing surface, with a flange receiving surface located just below the level of the tray sealing surface; at least one clamp member in each of said recesses and including a portion extending inwardly to a position directly over said flange receiving surface; actuator means for moving said clamp members away from the corresponding flange receiving surface to permit packaging material to be inserted therebetween; and means to urge each clamp member towards its flange receiving surface to engage and grip any packaging material inserted therebetween; said clamp members being located at least substantially entirely below said planar sealing surface, whereby a rigid package part can be placed on the tray to lay fiat against the package section flanges over said sealing surfaces.

7. Apparatus as claimed in claim 6, wherein said flange receiving surface slopes at an angle downwardly away from said flange sealing surface, said clamp member portion being disposed at an angle with respect to said flange receiving surface to provide an effective localized grip in engaging the packaging material.

8. Apparatus as claimed in claim 6, wherein said clamp member is mounted on said tray for pivotal movement about a point outboard of said flange receiving surface and in a plane transverse to the direction of tray movement.

9. Apparatus as claimed in claim 8, wherein said pivot point is no higher than said clamp member portion, whereby to ensure a continuous lateral movement of said clamp member portion outboard of the tray as the clamp member pivots up away from said flange receiving surface, said actuator means being engaged with said clamp member at a location between said clamp member portion and said pivot point.

10. Packaging apparatus of the type having a plurality of elements mounted for simultaneous movement around a closed path to carry cup-shaped package sections having side flanges, said elements comprising first and second sets of laterally-spaced means each including a receiving member and a cooperating clamp member, said first and second sets being disposed to be positioned on opposite sides of said package sections adjacent said side flanges respectively; each clamp member having an end portion which extends tranversely towards the package cup and which is located above a part of the corresponding receiving member to permit gripping any packaging material inserted therebetween; means mounting said clamp members for pivotal movement with respect to said receiving members at a pivot point outboard of said end portion; actuator means arranged to rotate said clamp member about said pivot point in a plane transverse to said direction of movement so as to separate said end portion and said receiving member part and permit packaging material to be inserted therebetween; and means urging said end portion towards engagement with said receiving member part to grip any packaging material inserted therebetween and thereby permit the package sections to be clamped at their side flanges, said pivot point being so located with respect to said receiving member that the end portions of said clamp members move laterally away from said package sections when the clamp member is rotated out of engagement with its corresponding receiving member part, thus providing increased lateral space for insertion of the packaging material.

11. Packaging apparatus of the type having a plurality of trays mounted for simultaneous movement around a closed path, said trays comprising wall means including front and rear walls with said walls extending therebetween; said walls defining cavities adapted to receive cup-shaped package sections having flanges around the mouths thereof, said walls presenting at the tops thereof flange sealing surfaces forming a continuous planar surface extending around the tray cavities immediately adjacent thereto; a packaging head adjacent said path at one operating position therealong and reciprocable towards and away from said trays, said packaging head including a peripheral element adapted to seat down against the sealing surfaces of a tray at said operating position to produce a hermetic seal of the package section in that tray; said trays being provided with recesses outboard of the side wall sealing surfaces; said recesses being formed to extend part Way beneath said peripheral element of said packaging head when the latter is engaged with the tray; each recess being formed at a position closely adjacent the corresponding side wall flange sealing surface with a flange receiving surface which is vertically located just below the level of the sealing surface and "directly beneath said peripheral element; at least one clamp member in each of said recesses and including an end portion extending inwardly to a position directly over said flange receiving surface; means for moving said clamp members upwardly away from said flange receiving surface When said packaging head is disengaged, to permit packaging material to be inserted between the clamp member and the corresponding receiving surface; and means to urge each clamp member towards its flange receiving surface to engage and grip any packaging material inserted there-between; said clamp member end portions being vertically located at a level below said planar sealing surfaces, whereby to avoid interference with said peripheral element when said packaging head is engaged with said tray.

References Cited UNITED STATES PATENTS 3,061,984 11/1962 'Mahairy 53-112 X 3,283,469 11/1966 McBrady et al. 53-112 X TRAVIS S. MCGEHEE, Primary Examiner.

Images