US2859572A - Packaging - Google Patents

Description

PACKAGING Filed July 5, 1956 FIG. 2

nite 2,859,572 Patented Nov. 11, 1958 2,859,572 PACKAGING Leslie John Moncriefi, London, England, assignor to British Celanese Limited, a British company This invention relates to packaging and provides a simple and inexpensive method and apparatus for sealing objects, such as small open topped boxes containing vegeztable products, in transparent wrapping film.

An excellent method of packaging some vegetable products, e. g. mushrooms, cherries, tomatoes, strawberries, raspberries, is to charge the product into an open boxshaped container e. g. of cardboard, and to provide an outer cover for the box (enclosing the open top) of transparent wrapping film of plasticised cellulose acetate (such as is sold under the registered trademarks Clarifoil and "Cellastine) sealed in position. The product packaged in this way is clearly visible through the layer of transparent film, and this film while protecting the product from contamination is sutficiently porous to allow gaseous interchange between the space containing the product and the outer atmosphere. Thus the condensation of moisture within that space and the undue accumulation therein of gases evolved by the product are avoided and the product does not quickly lose its freshness.

The provision of the outer cover of transparent wrapping film may be effected in two stages. In the first stage a sheet of the film of length somewhat longer than the perimeter of the cross-section of the box (to provide an overlap for making a cemented seam) and somewhat wider than the length of the box, to provide flaps for end-sealing, may be wrapped round the box to envelop it in a tube of rectangular cross-section, having a cemented seam along the bottom of the box, and projecting beyond each end of the box. In the second stage the projecting ends of the tube may be folded to form flaps which are pressed against the ends of the box and sealed in position. These operations if done entirely by hand are laborious and slow. Machines are available for applying the transparent outer cover mechanically, but these machines are very costly and complex and there are many small growers whose output is far from justifying the cost of such a machine The primary object of the present invention is to provide a simple and inexpensive apparatus which will decrease the labour and increase the speed at which, the wrapping and sealing can be effected.

Of the two stages referred to above the second presents little difiiculty once the first has been achieved, i. e. once the box has been enclosed in a tubular covering of the wrapping film closing the open top of the box extending some distance beyond each edge of the box, and cemented along the bottom of the box. The particular object of the present invention is to provide a simple mechanical means of effecting this first stage. An apparatus for this purpose will now be described, with reference to the accompanying diagrammatic drawing, which is in part sectional elevation and in which Figure 1 shows the apparatus at the beginning of the operation and Figure 2 at the end thereof.

On a suitable base plate there is mounted a fixed table 11 for supporting the box 12 with its open top upwards. Behind this is a spool carrier for carrying a spool 13 of the film 14. Between this and the table is a guide for guiding the film 14 from the spool to the upper surface of the box resting on the table. A

fixed, preferably serrated, knife 16 extends across and immediately above the path of the film from the spool to the box so as to contact the upper surface of the film. Forward of the fixed table is a movable table 17, of the same height as the fixed table and guided by side rails 18 engaging the sides of the table so as to be capable of running towards or away from the fixed table, both tables being wider than the width of the film and the rear edge 19 of the movable table and the forward edge of the fixed table being parallel with the axis of the spool. Forward of the movable table is a stop (not shown) to limit forward movement of said table and extending across the top of the movable table is a stop 20 for limiting forward movement of the box when the latter is slid along that table. The stop is adjustable to accommodate boxes of various widths. Extending parallel with and below the rear edge of the movable table is clamped a trough 21 accommodating a wick 22 which projects backwards as far as the rear edge of said table. This trough is to hold a solvent or adhesive for the film. The trough with its wick is adjustable as to height to deal withboxes of various dimensions. Projecting forwards from the forward end of the fixed table is a horizontal tongue 23, having a horizontal V-groove 24, the mouth of the groove being several times as wide as the thickness of the wick. This tongue, like the wick, is adjustable as to height to deal with packages of various cross-sectional dimensions. In operation it is adjusted so that when the movable table is moved backwards the wick enters the V-groove. An adjustable stop extending across the fixed table may be provided to locate the box in the appropriate position thereon.

The apparatus is' operating as follows:

The box containing the productis placed on the fixed table-with its sides parallel with the forward edge of the tongue. Preferably an adjustable finger 25 is provided forward of the fixed table to indicate the position to which the forward edge of the film must be drawn to provide the desired length'between this edge and the knife, and the position of the box on the fixed table is such that the middle line of the box coincides with the middle line of this length. The appropriate length of film is then drawn from the spool and cut perpendicular to its length by means of the knife. With the film covering the open top of the box and. hanging down to the same extent on both sides thereof, the box is moved horizontally by hand from the fixed table on to the movable table and slid along that table until it comes up against the stop thereon. Duringthis sliding movement the rear edge of the movable table tucks the forward part 26 of the film length 27 hanging down from the box under the bottom of the box, so forming half of the tube which is to envelope the box and leaving the rearward part 28 of the length of film hanging down into contact with the wick. The movable table is now moved towards the fixed table until the wick presses this rearward end of the film length into the V-groove of the tongue projecting from the fixed table. The box is now slid in a rearward direction along the fixed table. This draws the rearward end of the film length out of the V-groove and in so doing smears its outer surface with thesolvent supplied by the wick. Further rearward movement of the box causes the top of the fixed table to fold the solvent wetted length of film under the layer of film' that has already been folded under the bottom of the box, and seals the two layers of film together to form a seam 29 running along the bottom of the box from end to end. This completes the operation of forming the envelope and it now remains only to seal to ends of the tube of rectangularcross-section in which the box is enclosed. 7 Means for doing this will be referred to below.

As will be appreciated from the specific description given above, apparatus according to the invention for providing the box with the tubular envelope comprises the following integers in combination:

(1) A fixed table for supporting the box.

(2) Fixed means for rotatably mounting, a spool; of Wrapping film.

(3) Means for rapidly cutting the film between the box and the spool to obtain a predetermined length (sufficient to form the envelope) in a position such that when released after cutting it covers the open end of the box resting transversely on the table and hangs down to about the same extent on either side of the box.

(4) A movable table ofthe same height as the fixed table guided to be capable of movement towards and away from the fixed table.

(5) A wick or the equivalent extending'parallel with and below the rear edge of the movable table, and projecting backwards as far as the rear edge of said table at such a height as to engage therear overhang of the film length on the box.

(6) A fixed tongue projecting forwards from the fixed table and extending across said table parallel to the forward edge thereof at such a height that when the movable table is moved backwards the wick or the like enters a V-groove in the leading edge of the tongue and traps the rear overhang of the film length on the box in said groove.

' Although for applying the solvent or cement a wick co-operating as described with a V-grooved tongue is the preferred arrangement, alternatives are possible. The wick might for instance by replaced by a furnishing roll dipping in a trough of solvent or cement and cooperating with an arcuate fixed surface. The essential feature is that the rear overhang of the film length is gripped between a solvent applying member contacting the forward surface of said overhang and a fixed surface contacting the rear surface of said overhang so that when the box is moved further back along the fixed table the forward surface of the overhang is wiped over the solvent applying member before the overhang is tucked under the box, beneath the layer of film already folded under the box, and cemented to said layer.

The operation of providing the envelope involves the following sequence of steps:

(1) Drawing a predetermined length of film from a spool over the top of the box, cutting it and releasing it so that it covers the top of the box and hangs down and beyond each side to about the same extent, the total overhang beyond the sides of the box being greater than the width of the box but less than twice said width, the film being sufficiently wider than the length of the box to project at each end enough to form end flaps for closing the package. 7

(2) Moving the box forwards on to and along a temporarily stationary horizontal surface and causing the forward overhang of the film length by said movement to be tucked under the box.

(3) Moving the box backwards with said surface and towards the end of said movement causing the rear overhang of the film length. to be nipped between a horizontal rearwardly projecting solvent applying member that moves with said surface engaging the forward surface of said rear overhang and a' fixed forwardly-project ing surface.

(4) Moving the box further backwardsalong a fixed horizontal surface so as to draw said rear overhang out. of contact with the solvent applying member, fold it under the layer of film that has already beenfolded under the box and cement the two together.

The completion of the package can be effected by folding the ends of each tubular projection to form a system of flaps covering eachend of the box and sealing said flaps in position. Preferably, this is done by forming from each of the projecting ends of the tube a pair of horizontal flaps and a pair of vertical flaps, and at each end of the object folding one pair of said flaps back against said end, then-folding the other pair back on top of the first pair and sealing them in position.

For completing the package a folding box of the following construction may be employed:

The. box is without ends or top. It has two vertical side walls the same distance apart as the length of the package. to be made and raised slightly above the base (supported in this position by brackets allowing clearance for the ends-of the tube). From the side walls two fingers project forwards. In front of these are mounted two similar rearwardly projecting fingers that can be moved back into contact with the forward projecting fingers. Through each side wall is cut a rearward and upwardly inclined slot followed by a rearward and downwardly inclined slot. The lower edges of these slots are bevelled and in the neighbourhood of each slot a wick is provided for applying solvent or cement to the film surfaces to be cemented. In operation the partly formed package (a box containing the produce to be packed and provided with a tubular envelope of film by the method described above) is placed transversely in contact with and in front of the forwardly projecting fingers. The rearwardly projecting fingers are then moved backwards so that they engage the forward surfaces of the projecting ends of the tube enveloping the produce box, forming from each of these surfaces a flap which is pressed against the respective end of the box. The box is then moved backwards past the forward projecting fingers which operate in the same way on the rear surfaces of the project ing ends forming a second pair of flaps which are pressed down onto the first pair. This leaves two horizontal flaps projecting at each end of the produce box. The produce box is pushed backwards between the side walls of the folding box with one pair of horizontal flaps beneath and one pair above the side walls of the folding box. During this movement the lower flaps ride up the upwardly directed'slots and owing to the bevel are first pressed against the outer surfaces of the folding box side walls where they receive the necessary dosage of solvent or cement and each is then pressed by the inner surface of that part of the side wall between the two slots against side flaps of the package and cemented to them. The upper flaps in the same way ride down the downwardly inclined slots, are turned out and pressed against the outer surface of the side walls of the folding box, where they are dosed with solvent or cement.

In employing a folding box of the kind referred to above to seal the ends of the package in conjunction with the apparatus specifically described for providing the produce box with the tubular envelope, the folding box is preferably mounted on the fixed table behind the position to be occupied on that table by the produce box, the rearwardly projecting fingers of the folding box being slidably mounted if desired on sides of the movable table, and normally held in a forward inoperative position by springs. With this arrangement, once the tube has been formed about the produce box the rear projecting fingers are moved backwards to effect the first stage in the end-sealing, i. e. the formation of the first pair of side flaps, and the package is then moved backwards through the folding box and removed at the end of that box with the ends sealed.

The following example illustrates the process of the invention:

Example The apparatus for forming the envelope about the pro duce box was as specifically described above. The rearward projecting fingers of the folding box were slideably mounted on the movable table as described and the folding box proper was mounted at the rear end of the fixed table.

The apparatus was employed to pack mushrooms in an open topped cardboard carton of length 7%. ins., width 4 ins. and depth 2 ins. The fixed and movable tables, wick and fixed knife were all 14 ins. wide. The wick and the centre of the V-groove in the tongue were fixed at 1 /2 ins. below the table tops. The adjustable stop was fixed 4 ins. forward of the rear edge of the movable table. The wick was level with this edge. The spool holder was provided with a spool of plasticised cellulose acetate wrapping film of thickness 1 mil and width 13 ins. sold under the registered trademark Cellastine. The index finger was set at a distance of 12 /2 ins. in front of the knife, i. e. to allow for an overlap at the seam of /2 in.

The box containing the mushrooms was placed on the fixed table in such a position as to be midway between the knife and the index finger, the sides of the box being parallel with the forward edge of the table. The trough for the solvent was charged with ethylene glycol monomethyl ether and the wick thoroughly impregnated with this solvent (acetone could also be used but its volatility makes it less convenient). With the movable table in its forward position the film length drawn off was cut out by drawing it across the knife, and with this film length covering the open top of the box and hanging down on either side, the box was moved horizontally on to the movable table and slid along that table until stopped by the adjustable stop. The movable table was then run back along its rails until the wick forced the rearward overhang of the film length into the V groove of the tongue. Next the partly formed package was slid backwards along the top of the fixed table to complete the formation of the tubular envelope. The rear projecting fingers of the folding box were then moved backwards after which the package was moved backwards through the folding box where the second pair of side flaps were formed and the top and bottom flaps were formed and cemented to the other flaps. The package was removed from the rear end of the folding box.

The operation was then repeated on a fresh box of mushrooms. An untrained operator carried out the process at the rate of eight packages per minute.

The invention has been described with particular reference to providing open topped boxes with a transparent covering of plasticised cellulose acetate wrapping film. It will be appreciated, however, that the method and apparatus can be applied with suitable modifications to the wrapping of packages of other shapes, especially other shapes in the form of prisms having pairs of parallel sides; that the box or other container wrapped need not be open topped (although an open topped container gives the advantage that the product is visible) and that the method and apparatus of the invention are not limited to the use of plasticised cellulose acetate as the wrapping material, although this material has been found most suitable for the purpose envisaged. With Wrapping material that cannot be cemented by the application of a solvent alone, a cement may be used instead of the solvent. The gauge of the wrapping film may, for example, range from 0.8 to 5 mils. The film is preferably transparent and colourless but it may be translucent or opaque and coloured. It may of course be printed upon and/ or ornamented in various Ways.

Having described my invention, what I desire to secure by Letters Patent is:

1. Process for enclosing a box-shaped object in a tubular covering of wrapping film as a step in packaging said object, which comprises drawing a predetermined length of film from a spool over the top of said object, cutting off said length and releasing both ends thereof so that it covers the top of the object and hangs down beyond each side to about the same extent, moving the object forward on to and along a temporarily stationary horizontal surface and causing the forward overhang of the film length by said movement to be tucked under the object, moving said surface, while it carries the object, backwards and towards the end of said movement causing the rear overhang of the film length to be nipped between a horizontal rearwardly projecting solvent-applying member that moves with said surface, engaging the forward surface of said rear overhang, and a fixed forwardly projecting surface, and then moving the package further backwards along a fixed horizontal surface so as to draw said rear overhang out of contact with the solvent-applying member, fold it under the layer of film that has already been folded under the object and cement the two film layers together, the total overhang of wrapping film beyond the sides of the object being greater than the width of the object but less than twice said width, and the film being sufliciently wider than the length of the object to project at each end enough to form end flaps for closing the package.

2. Process according to claim 1, wherein the package is a small open topped box containing fruit or other perishable foodstuff.

3. Process according to claim 2, wherein the wrapping material comprises a film of plasticised cellulose acetate of thickness 0.8-5 mils.

4. Process for packaging a box-shaped object, which comprises forming a tubular envelope about said object as claimed in claim 1 and completing the package by folding the ends of each tubular projection to form a system of flaps covering each end of the box and sealing said flaps in position.

5. Process according to claim 1, wherein the package is completed by forming from each of the projecting ends of the tube a pair of horizontal flaps and a pair of vertical flaps, and at each end of the object folding one pair of said flaps back against said end, then folding the other pair back on top of the first pair and sealing them in position.

6. Apparatus for enclosing a box-shaped object in a tubular covering of wrapping film by the method claimed in claim 1, which comprises a fixed table for supporting the object, fixed means for rotatably mounting a spool of said film, means for rapidly cutting the film between the object and the spool to obtain a predetermined length, a movable table of the same height as the fixed table and guided to be capable of movement towards and away from the fixed table, both tables being wider than the width of the film and the forward edge of the fixed table and the rear edge of the movable table being parallel with the axis of the spool, a stop to limit forward movement of the movable table, an adjustable stop extending across the top of the movable table for limiting forward movement of the partly formed package when the latter is slid along said table, a solvent-applying member fixed to the movable table and extending parallel with and below its rear edge, said member projecting at such a height as to engage the rear overhang of the film length on the partly formed package, a fixed tongue projecting forwards from the fixed table and extending across said table parallel to the forward edge thereof at such a height that when the movable table is moved backwards,

the said solvent-applying member enters a depression in the leading edge of said tongue and traps the rear overhang of the film length on the partly formed package in said depression.

7. Apparatus according to claim 6,'wherein said solvent-applying member comprises a trough clamped to the rear end of the movable table, said trough accommodating a wick which projects backwards as far as the rear edge of said table, said wick co-operating with a V-groove in the leading edge of said tongue.

References Cited in the file of this patent UNITED STATES PATENTS

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