Patent Description:
Typically, the pliable side walls of the folded board trays are pre-scored along their upper margin at the "flange fold" to enable the upper margin to be folded into a horizontal, outward position thereby forming the top flange.

However, often when the board trays/cartons are supplied by the manufacturer, the side walls are essentially vertical. As a consequence, when a film heat sealing head, having a flat contact surface, presses against the top edge of the tray/carton, if the side wall is vertical or close to vertical, an outwardly directed seal flange may not be correctly formed. Instead, the side wall, being pliable, may be crushed or may fold inwardly. As a consequence, a proper seal is not achieved between the film and the tray/carton. To help ensure that a proper sealing flange is formed, the flanges may have to be pre-broken by hand, or some other method used, which is time consuming as well as expensive.

The present application disclosure seeks to address the foregoing issue by providing a tool integrated into the heat sealing apparatus to "break" or otherwise fold the flanges outwardly so that an acceptable sealing flange can be created. As such, a top film can be heat sealed to the container, without causing damage to the container flange and also so that the container need not be pre-broken prior to applying the top film.

<CIT> discloses apparatus for producing a sealed container. A tray having a closed circumferential flange at its upper side is placed in a die and a plastic sheet placed over the flange. A stamp is then pressed against the plastic sheet and the flange, to compress the two together between a multitude of closed-circumferential parallel protruding ribs on the stamp and a counter press surface on the die, such that a multitude of closed parallel seals between the plastic sheet and the flange is obtained.

<CIT> discloses a method of forming a carton blank into a carton. Firstly, the blank is bent along fold lines to form an open-ended tube with a rectangular cross-section.

Tabs at a bottom end of the tube are then folded inwardly and an end to the tube folded over the tabs in an overlapping arrangement. The document does not disclose how this folding is achieved. Subsequently a mandrel is placed on the inside or outside of the tube and against the overlapping portion of the end closure before an ultrasonic horn is placed against the overlapping members to seal them together. The top end of the tube is closed after the tube is filled with liquid, following a different process. Continuous, connected, tabs at the top end of the tube are subjected to a limbering process where creasing pins are used to collapse two adjacent corners between the tabs inwards. Subsequently the tabs are folded inwardly and downwardly into the carton, although the document does not disclose how this is achieved. After this the filled container is placed into an anvil with a beveled upper edge surrounding the container, a closure is folded over the open end of the container and a die with a corresponding shape to the anvil is placed over the closure. This enables the edges of the closure to be sealed to the outside face of the tabs, and the inner face of the tabs to be sealed against the end perimeter portion of the side panel of the container. This forms an external sealing strip to the container.

<CIT> discloses a container structure with a body of conical shape formed from a sheet material. The free edge of the material defining an opening to the container is turned outwardly to form a rim by urging a die having a frustro-conical shape surrounded by a flat annular surface into contact with the free edge.

In accordance with one embodiment of the present disclosure, an apparatus is provided for assisting in forming seal flanges along the top portion of the pliable side walls of a carton. The system includes a plurality of camming surfaces positioned to engage the top portion of the side walls of the carton an actuator to move the camming surfaces against the top portion of the side walls of the carton in an outward direction relative to the interior of the carton to force the top portion outwardly relative to the interior of the carton.

The carton has a bottom and the actuator moves the camming surfaces towards the bottom of the carton to bear against the top portion of the side walls of the carton.

In the apparatus the camming surfaces are contoured to extend upwardly and outwardly relative to the upper edge portions of the carton side walls thereby to force the upper edge portions outwardly as the camming surfaces are moved toward the bottom of the carton.

In the apparatus the camming surfaces are part of a linear cam.

In the apparatus the actuator is powered by a sealing assembly functioning to seal the carton.

In the apparatus the sealing assembly comprises a seal profile for sealing a film to the formed seal flanges of the carton.

In the apparatus further comprising a holder for receiving the carton therein, the holder comprising a perimeter extending along the upper portion of the carton.

In the apparatus the holder perimeter extends along the exterior of the upper portion of the carton side walls.

In the apparatus the perimeter surrounds an upper portion of the carton side walls.

In the apparatus the perimeter comprises a ledge extending around the exterior of the upper portions of the side wall.

In the apparatus the ledge comprises a horizontal abutment surface for abutting against the formed seal flanges.

In the apparatus the holder comprises a base for supporting the bottom of the carton during the operation of the camming surfaces.

In accordance with another embodiment of the present disclosure, a tray sealer is provided. The tray sealer includes a bottom tool assembly for receiving trays to be sealed, the trays having upwardly extending, pliable side walls. The tray sealer also includes a top tool assembly, comprising a camming structure for forcing the top margins of the tray side walls outwardly relative to the trays to initiate the formation of a sealing flange, the camming structure having a plurality of camming surfaces. The tray sealer further includes an actuator for moving the camming structure relative to the base tool assembly to press the camming surfaces against the top margins of the tray side walls to force the top margins of the side walls outwardly relative to the side walls.

In the tray sealer the camming structure comprises a plurality of camming surfaces contoured to press in unison against the top margins of the tray side walls as the camming structure is actuated by the actuator.

In the tray sealer the camming surfaces project outwardly relative to the tray in the direction along the tray side walls from the bottom of the tray to the top of the tray.

In the tray sealer the camming structure comprises a camming plate and wherein the camming surfaces projecting from the camming plate.

In the tray sealer the camming plate is in the form of a perimeter structure having an open central portion to provide clearance for portions of the top tool assembly.

In the tray sealer the camming surfaces project from the perimeter structure.

In the tray sealer the camming surfaces are disposed at the distal ends of wedge elements that project from the camming plate.

In the tray sealer the actuator causes the camming plate to move the camming structure toward the bottom tray assembly as the camming surfaces engage against the tray side walls.

In the tray sealer the actuator acts on at least one of the base tool assembly and the top tool assembly to move the bottom tool assembly and top tool assembly towards and away from each other resulting in engagement or disengagement of the camming structure with the tray side walls.

In the tray sealer the top tool assembly comprising a seal profile to engage the outwardly turned top margins of the tray side walls to form sealing flanges extending outwardly to form the side walls.

In the tray sealer the seal profile pressing the outwardly turned top margins of the tray side walls against the base tool assembly to form the sealing flanges.

In the tray sealer the seal profile pressing a sealing film against the tray for sealing the tray.

In the tray sealer the seal profile comprising a sealing surface to seal a film to the formed sealing flange of the tray.

In the tray sealer the top tool assembly further comprising a linkage assembly for sequencing the operation of the camming structure relative to the operation of the seal profile.

In the tray sealer the top tool assembly further comprising a film cutter cutting the file to correspond to the shape of the tray flange after the sealing film is sealed to the tray flange.

In another embodiment of the present disclosure, a method is provided for sealing a container having an open top defined by pliable, upwardly extending side walls. The method includes:.

The method also includes prior to pressing the camming surface against the side walls of the container, placing the container into a holder to secure the container in stationary position.

In the method, in placing the container in a holder, an abutment extends along and outwardly of the container to provide an abutment surface against which the top margin of the container side walls are pressed to form the sealing flange.

In the method, a plurality of camming surfaces are used to press against the top portion of the side walls to form the top margins of the side walls into an outwardly disposed position.

In the method, the camming surfaces are spaced apart from each other along the container side walls.

In the method, the camming surfaces are moved in unison.

In the method, the camming surface projects form a camming structure.

In the method, the camming structure is actuated to move in a linear direction as the camming surfaces press against the top portions of the container side walls.

The description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.

The present application may include references to "directions," such as "forward," "rearward," "front," "back," "ahead," "behind," "upward," "downward," "above," "below," "top," "bottom," "right hand," "left hand," "in," "out," "extended," "advanced," "retracted," "proximal," and "distal. " These references and other similar references in the present application are only to assist in helping describe and understand the present disclosure and are not intended to limit the present invention to these directions or specific references.

The present application may include modifiers such as the words "generally," "approximately," "about", or "substantially. " These terms are meant to serve as modifiers to indicate that the "dimension," "shape," "temperature," "time," or other physical parameter in question need not be exact, but may vary as long as the function that is required to be performed can be carried out. For example, in the phrase "generally circular in shape," the shape need not be exactly circular as long as the required function of the structure in question can be carried out.

In the following description, various embodiments of the present disclosure are described. In the following description and in the accompanying drawings, the corresponding systems assemblies, apparatus and units may be identified by the same part number, but with an alpha suffix. The descriptions of the parts/components of such systems assemblies, apparatus, and units that are the same or similar are not repeated so as to avoid redundancy in the present application.

In the present application and claims, references to "tray," "carton," and "container," are used interchangeably and are meant to include all manner board, folded board or paper containers.

The sealing apparatus <NUM> of the present disclosure includes in basic form a top tool assembly <NUM>, see <FIG>, that cooperates with a bottom tool assembly <NUM>, see <FIG> and <FIG>, to apply a plastic sealing film <NUM> to the open top of a carton or tray <NUM>, or similar type of container.

The pliable side walls <NUM> of the carton/tray <NUM> to be sealed may close to vertical, as shown in <FIG>. The sealing apparatus <NUM> of the present disclosure is capable of forming horizontal, outwardly directed sealing flanges <NUM> along the upper edge of the side walls <NUM>. To this end, the carton/tray <NUM> is placed within the receiving bottom tool assembly <NUM>. Thereafter, the top tool assembly <NUM> and bottom tool assembly <NUM> are pressed together to form the sealing flanges <NUM> and also to seal the top of the carton/tray <NUM> with the sealing film <NUM>.

Referring specifically to <FIG> and <FIG>, the bottom tool assembly is constructed with a receiving structure <NUM>, is spaced above a base <NUM> by a plurality of columns <NUM> projecting from the base at the corner portions of the receiving structure. The receiving structure <NUM> includes a central opening <NUM> having a shape corresponding to the shape of the upper portion of the carton/tray <NUM> so that the carton is received within the opening and the upper outer margins of the carton bear against the upper edges of the opening <NUM> when the carton rests on a central ejection pad <NUM>, see <FIG>.

The ejection pad <NUM> is supported by retractable and extendable columns <NUM> which are capable of retracting downwardly when the flanges <NUM> are formed in the carton <NUM>, as described below. After flanges have been formed, columns <NUM> are capable of pushing the carton upwardly relative to the receiving structure <NUM> for removal of the formed carton from the bottom tool assembly <NUM>.

The column structure <NUM> can be spring loaded, and/or pneumatically or otherwise actuated to place the carton <NUM> at the correct height relative to the bottom tool receiving structure <NUM> and to reduce in height during the forming of the carton flanges <NUM> and thereafter increase in height to eject the formed carton from the tool receiving structure <NUM>.

The receiving structure <NUM> includes an inner rim <NUM> and an outer rim <NUM> that are spaced apart from each other by a clearance channel <NUM>, the purpose of which is described below. The inner rim <NUM> forms a perimeter around the upper portion of the exterior of the carton sidewalls. The top of the inner rim <NUM> forms a ledge that extends around the carton side walls. This ledge functions as an abutment surface against which the top flanges <NUM> are formed by the apparatus <NUM>.

A rubber or otherwise elastic insert <NUM> is engaged within a "T" channel formed in the top of outer rim <NUM>. A corresponding rubber or other elastic insert <NUM> is disposed within a "T" shaped channel formed in the top portion of the inner rim <NUM>. As shown in <FIG>, when the carton <NUM> to be formed is placed in the bottom tool assembly <NUM> and supported by ejection pad <NUM>, the upper margins of the side walls of the carton extend upwardly beyond the elevation of the top of inner rim <NUM> and the insert <NUM> disposed therein.

Referring initially to <FIG>, the top tool assembly <NUM> includes a planar film clamping plate <NUM> located at the base of the tool assembly. One purpose of the film clamping plate is to hold the film <NUM> against the bottom tool assembly <NUM> while the film is sealed to the carton flanges <NUM> and then while the film is cut to the shape defined by flanges. To this end, the film clamping plate <NUM> is designed to set against the bottom tool assembly <NUM> so that a ridge <NUM> that projects downwardly from the underside of the clamping plate aligns with a resilient insert <NUM> positioned into the upper surface of the receiving structure <NUM> thereby to securely hold the sealing film in place.

The sealing film is threaded or otherwise guided in place beneath the film clamping plate <NUM> by a pair of elongated infeed guide rollers <NUM> and <NUM> that are mounted in spaced parallel relationship to the adjacent edge of the clamping plate <NUM> by formed brackets <NUM>. The brackets <NUM> include a top flange portion that is secured to the top surface of the margin of the clamping plate by appropriate hardware members. The sealing film is threaded to pass in the gap existing between the two guide rollers <NUM> and <NUM>.

An outfeed guide assembly is mounted on the opposite side of the clamping plate <NUM>, being composed of a generally flat guide blade <NUM> abutting the adjacent edge of the clamping plate and an elongated circular guide roller <NUM> spaced outwardly of the guide blade <NUM>. As in the case of the infeed guide rollers <NUM> and <NUM>, the outfeed guide blade <NUM> and roller <NUM> are mounted to the film clamping plate <NUM> by formed brackets <NUM>. The brackets <NUM> include a top flange portion that overlaps the top marginal portion of the clamping plate. The brackets <NUM> likewise are secured to the film clamping plate <NUM> by hardware members extending downwardly through openings formed in the brackets <NUM> to engage within threaded openings formed in the clamping plate <NUM>.

The guide blade <NUM> includes a wider central portion <NUM> that tapers to narrower end portions towards the opposite ends of the guide blade. The wider portion <NUM> is receivable within an opening formed in the roller of sealing film after being cut to sever the portion of the film sealed to the container. This helps keep the film centered on the rollers <NUM>, <NUM> and <NUM>. Of course, the guide rollers <NUM>, <NUM> and <NUM> and the guide blades <NUM> can be mounted to the film clamping plate <NUM> by means other than brackets <NUM> and <NUM>.

As shown in <FIG>, the top tool assembly <NUM> also includes a formed seal profile <NUM> consisting of a central portion <NUM> and an outer flange portion <NUM> extending around the central portion <NUM>. The flange portion <NUM> coincides in size with the inner rim <NUM> of the receiving structure <NUM> of the bottom tool assembly, described above.

In one form of the present disclosure, the seal profile <NUM> is formed from metallic material so as to efficiently transfer heat to the portion of the sealing film <NUM> coinciding with the area of the flange portion <NUM>.

Heat is applied to the seal profile <NUM> by a heating element plate <NUM> positioned against the upper surface of the central portion <NUM> of the seal profile. A heating element clamping plate <NUM> is used to clamp the heating element plate <NUM> between the clamping plate and the central portion <NUM> of the seal profile <NUM>.

Electrical energy is routed to the heating element plate <NUM> by a cord assembly <NUM> that extends downwardly from an overhead electrical source.

Referring to <FIG>, a camming structure <NUM> in the form of a camming plate <NUM> having an open perimeter portion is positioned just outwardly of the heating element plate <NUM> and the heating element clamping plate <NUM> so as to closely encircle these components. The camming structure <NUM>, as described below, is supported for vertical movement relative the bottom tool assembly <NUM>, and in particular the receiving structure <NUM>.

The camming structure <NUM> includes a plurality of wedge elements <NUM> that depend downwardly from the corners of the camming plate <NUM> to interact with the upper edge portions of carton <NUM>. The wedge elements <NUM> slide through vertical slots <NUM> formed in the outer margins of the seal profile, so as to be in proper position relative to the carton <NUM>.

The bottom ends of the wedge elements <NUM> taper inwardly in the downward direction (outwardly in the upward direction) so as to define angular or curved camming or forming surfaces <NUM>. As the camming structure <NUM> is lowered relative to carton <NUM>, the camming or forming surfaces <NUM> engage against the upper edges of the side walls <NUM> of the carton <NUM> and cause such upper edges to turn or fold outwardly relative to the carton. The camming surfaces are part of a linear cam structure in the sense that wedge elements <NUM> are moved in a linear direction to cause the camming surfaces <NUM> to operate against the upper edges of the carton side walls <NUM>, which upper edges function as cam followers and deform outwardly under the linear movement of the wedge elements.

The downward travel of the camming structure <NUM> stops once the flanges <NUM> at the upper margins of the carton <NUM> are sufficiently turned outwardly so that such partially formed flanges are then contacted and further formed by the flange portions <NUM> of the seal profile <NUM>. The flange portions <NUM> presses the carton flanges <NUM> downwardly against the top surface of the inner rim <NUM> of the receiving structure <NUM> to complete the forming of the flanges <NUM> and also to provide a surface for film <NUM> to seal against.

It will be appreciated that during the above-described downward travel of the camming structure <NUM>, sealing film <NUM> is already in place over the top of the carton <NUM>. However, the camming surfaces <NUM> do not puncture through the sealing film <NUM> since the wedge elements <NUM> stop their downward travel once the partially formed flanges are turned outward sufficiently that the flange portions <NUM> of the seal profile contact with the flange <NUM>.

Although wedge elements <NUM> are illustrated in the drawings as located at or near the corners of camming plate structure <NUM>, the wedge elements can be positioned at other locations with respect to the camming plate structure. Also, the number of wedge elements can be increased or decreased from that shown in the figures, for example, depending on whether the top margins of all of the sides of the container need to be formed into flanges. Also, the placement and number of the wedge elements may depend on the shape of the carton. The carton shown in the figures is square or rectangular in shape, but the carton can be formed in other shapes, such as circular, triangular, pentagonal, hexagonal, elliptical, oval, etc..

As noted above, the bottom camming surfaces <NUM> of the wedge elements <NUM> are tapered so as to cause the container wall upper edge portions to fold or turn outwardly as the camming structure is lowered relative to the carton <NUM>. The camming surfaces of the wedge elements <NUM> can be in the form of a straight line or bevel, but can also be in other shapes, such as, for example, curved in an upwardly concave manner.

Next, referring to <FIG> and <FIG>, the camming structure <NUM> is interconnected to the film clamping plate <NUM> by a shorter connecting rod <NUM> extending upwardly from the camming structure <NUM> and a longer connecting rod <NUM> extending upwardly from the film clamping plate <NUM>. Both of the connecting rods <NUM> and <NUM> pass through vertical clearance bores <NUM> and <NUM> formed in an overhead top pressure plate <NUM>. The upper ends of the connecting rods <NUM> and <NUM> are interconnected by a lateral linkage plate <NUM> that is nominally disposed within a shallow depression formed in the upper surface of the top pressure plate <NUM>.

As described below, the top pressure plate <NUM> overlies the structure of the top tool assembly and can be connected to an overhead vertical actuating system (not shown) by four tool mounting pillars <NUM> that are affixed to the pressure plate <NUM> by hardware members extending downwardly from the pillars to engage within threaded openings formed in the pressure plate <NUM>. It is to be understood that rather than constructing apparatus <NUM> so that the top tool assembly <NUM> is powered or otherwise actuated to move towards and away from the bottom tool assembly <NUM>, the sealing apparatus <NUM> can be designed and operated so that the bottom tool assembly <NUM> moves up and down relative to the top tool assembly <NUM>, which remains stationary. Of course, if desired, both the top tool assembly and the bottom tool assembly can be constructed to move towards and away from each other, individually or simultaneously.

The pressure plate <NUM> is interconnected to film clamping plate <NUM> by a plurality of clamping screws <NUM> extending downwardly from at least each corner of the pressure plate <NUM> to engage with threaded openings formed in alignment in the film clamping plate <NUM>. Compression springs <NUM> are engaged over the exterior of the clamping screws <NUM> to nominally maintain the pressure plate <NUM> at an elevation above the clamping plate <NUM>. However, when the pressure plate <NUM> is moved further in the downward direction by a downward force imposed on the mounting pillars <NUM>, the pressure plate <NUM> slides relative to the clamping screws <NUM> causing the springs <NUM> to depress. As described before, when the downward movement of the pressure plate <NUM> reaches a certain level, the pressure plate then also moves relative to the connecting rods <NUM> and <NUM>.

The lowering of the pressure plate <NUM> also causes the downward movement of the camming structure <NUM>. In this regard, when the pressure plate <NUM> is lowered, the pressure plate pushes against compression springs <NUM>, which in turn push downwardly against the film clamping plate <NUM>. In turn, the film clamping plate <NUM> pulls downwardly on connecting rod <NUM> as well as on connecting rod <NUM> which is attached to connecting rod <NUM> via overhead linkage plate <NUM>. Since the camming structure <NUM> is attached to the lower end of the connecting rod <NUM>, the camming structure is also pushed in a downward direction. However, once the bottom of the film clamping plate <NUM> presses against the top of the bottom tool receiving structure <NUM>, the downward travel of the film clamping plate <NUM> stops, which also stops the downward travel of the camming structure <NUM>. However, the downward travel of the seal profile, and associated heating plate <NUM> and clamping plate <NUM>, can continue with the further downward travel of the overhead pressure plate, as described following.

The downward movement of the pressure plate <NUM> also causes the downward movement of the seal profile <NUM> as well as the heating plate <NUM> and clamping plate <NUM> located above the seal profile. Compression springs <NUM> are positioned between the top of the heating element clamping plate <NUM> and the underside of the top pressure plate <NUM>. Thus, as pressure plate <NUM> lowers, a downward force is also applied to the seal profile <NUM>. Subsequently, when the pressure plate <NUM> is raised upwardly to a retracted position, the compression springs <NUM> cause a separation between the pressure plate and the heating element clamping plate <NUM>. This separation is limited by hardware members in the form of cap screws <NUM> that extend downwardly through clearance holes <NUM> formed in the pressure plate <NUM> to engage with threaded holes formed in the clamping plate <NUM>.

Next, referring to <FIG>, the top tool assembly <NUM> also includes a blade carrier <NUM> which is in the form of a perimeter structure that is sized to surround the camming structure <NUM>. The blade carrier <NUM> is attached to the underside of the top pressure plate <NUM> by hardware members extending between the top pressure plate <NUM> and the blade carrier <NUM>. A thin rectangularly-shaped blade <NUM> is affixed to the inside vertical surfaces of the blade carrier <NUM> to extend downwardly from a shoulder <NUM>, to extend below the lower surface of the blade carrier. The blade is sized and positioned to closely fit between the central opening <NUM> of the clamping plate <NUM> and the exterior of the seal profile <NUM>. Since the blade carrier <NUM> is affixed to the top pressure plate <NUM>, as the top pressure plate raises and lowers, the blade <NUM> also raises and lowers to the same extent as the pressure plate.

The purpose of the blade <NUM> is to cut the sealing film <NUM> after the sealing film has been fused to the container flanges <NUM> from the heat and pressure applied by the sealing profile <NUM>. To this end, the blade <NUM> is formed with a sharp bottom edge <NUM>. A narrow upwardly open channel <NUM>, described above, is provided between the outer rim <NUM> and an inner rim <NUM> of the receiving structure <NUM> for receiving the bottom edge <NUM> of the blade <NUM>.

Next, describing the operation of the sealing apparatus <NUM>, referring especially to <FIG> and <FIG>, with the carton/tray <NUM> placed in the bottom tool assembly <NUM>, the upper edge of the carton extends above the upper surface of the receiving structure <NUM>. At this point, the bottom of the carton rests on the ejection pad <NUM>.

From the starting position of <FIG>, the top pressure plate <NUM> is driven downwardly by the mounting pillars <NUM> thereby compressing the springs <NUM> acting between the pressure plate <NUM> and the clamping plate <NUM>. Simultaneously, the camming structure <NUM> is lowered so that eventually the camming edges <NUM> at the bottom of the wedge elements <NUM> bear against the upper edge of the carton side walls <NUM>, see <FIG>. The cutting blade <NUM> is also simultaneously being lowered due to the lowering of the blade carrier <NUM> with the top pressure plate <NUM>.

As the top pressure plate <NUM> continues to lower, the wedge elements <NUM> also continue to lower thereby forcing the upper edges of the carton side walls to turn further outwardly. The downward travel of the camming structure <NUM> stops when the bottom of clamping plate <NUM> bears against the top of the outer rim <NUM> of the bottom tool receiving structure <NUM>, see <FIG>. At this point, the camming surfaces <NUM> of wedge elements <NUM> are disposed above the elevation of the carton flange <NUM> when fully formed.

As the top pressure plate <NUM> continues to lower, the carton flange <NUM> is further formed into a horizontal orientation by the flange portions <NUM> of the seal profile <NUM>, see <FIG> and <FIG>. When the seal profile flange portions <NUM> bear against the inner rim <NUM> of the receiving structure <NUM>, the downward travel of the seal profile <NUM> stops. However, the top pressure plate <NUM> does continue to move downwardly until the blade <NUM> cuts through the sealing film <NUM>. As this occurs, the blade lowers into the channel <NUM> located between the inner rim <NUM> and the outer rim <NUM>, see <FIG>. Simultaneously, springs <NUM> compress to enable the top pressure plate <NUM> to continue to lower relative the seal profile <NUM> towards the bottom tool assembly <NUM>.

It will be noted that when the top pressure plate <NUM> is in this fully downward position, the top pressure plate has lowered relative to the height of the connecting rods <NUM> and <NUM> since the downward travel (toward the bottom tool assembly <NUM>) of the clamping plate <NUM> and camming structure <NUM> had since ceased.

During the contact between the flange portions <NUM> of the seal profile <NUM> and the inner rim <NUM>, the heat from the seal profile creates a seal between the film <NUM> and the formed container flanges <NUM>. Once the seal has been formed and the sealing film <NUM> is cut by blade <NUM>, the downward load on the mounting pillars <NUM> is removed, which enables the compression springs <NUM> to expand or extend thereby separating the distance between the underside of the top pressure plate <NUM> and the heating element clamping plate <NUM> until the top of cap screws <NUM> bottoms against the counter bore formed in the top of pressure plate <NUM> thereby raising the seal profile <NUM> and associated heating plate <NUM> and clamping plate <NUM> upwardly.

Simultaneously with the expansion of springs <NUM>, the compression spring <NUM> expand to increase the distance between the top pressure plate <NUM> and the film clamping plate <NUM>. Once a sufficient separation has been achieved between the top pressure plate <NUM> and the film clamping plate <NUM>, the top pressure plate pushes upwardly against the lateral linkage plate <NUM> between the connecting rods <NUM> and <NUM> thereby retracting the camming structure <NUM> in the upward direction.

The upward movement of the top tool assembly results in a corresponding upward movement of the blade carrier <NUM>, and eventually the retraction of the cutting blade <NUM> to the fully retracted position shown in <FIG>.

Once the top tool assembly <NUM> has been sufficiently retracted upwardly, the sealing film <NUM> is advanced so as to place a new section of the film beneath the film clamping plate <NUM> thereby to be ready for the next cycle of the sealing apparatus <NUM>.

While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the scope of the invention as defined by the appended claims. For example, as briefly noted above, rather than operating the sealing apparatus <NUM> to lower and raise the top tool assembly <NUM>, instead the bottom tool assembly <NUM> can be raised and lowered relative to the top tool assembly. Further, both the top and bottom tool assemblies can be constructed to move towards and away from each other. If the sealing apparatus <NUM> is constructed so that the bottom tool assembly <NUM> moves relative to the top tool assembly <NUM>, the sequence of operation of the top tool assembly <NUM> as described above can remain the same.

Also, a singular top tool assembly <NUM> and bottom tool assembly <NUM> are illustrated. However, it will be understood that sealing machinery can be constructed with multiple top tool assemblies and bottom tool assemblies as singular tool sets so as to seal a plurality of cartons <NUM> at the same time. The singular tool sets can be actuated with a single top and/or bottom actuator.

Further, cartons may be provided wherein in two side walls (typically opposing), the top marginal portions may already be flared outwardly so as not to require further action by the camming structure. Rather, the camming structure can be adapted to focus on the other two opposed side walls in which the upper portions extend substantially vertically upward. As such, the positions of the wedge elements <NUM> can be modified to adapt to the particular carton side walls, which require their upper rim portions to be forced in the outward direction by the wedge elements <NUM>. For a carton with four sidewalls, the camming structure can operate on from one to four of the sidewalls. For cartons with a different number of sidewalls, the camming structure can operate on from <NUM> to all of the sidewall of the carton.

Claim 1:
An apparatus (<NUM>) for assisting in forming seal flanges (<NUM>) along the top portion of the pliable side walls (<NUM>) of a carton (<NUM>), comprising:
(a) a plurality of camming surfaces (<NUM>) positioned to engage the top portion of the side walls (<NUM>) of the carton (<NUM>);
(b) an actuator to move the camming surfaces (<NUM>); and
characterized in that the apparatus further comprises:
(c) a seal profile (<NUM>) having an outer flange portion (<NUM>), wherein, in use, the actuator is arranged to move the camming surfaces (<NUM>) against the top portion of the side walls of the carton in an outward direction relative to the interior of the carton to force the top portion outwardly relative to the interior of the carton to partially form flanges (<NUM>) whereupon the movement of the camming surfaces against the top portion of the side walls is stopped and the partially formed flanges are contacted and further formed by the flange portion (<NUM>) of the seal profile (<NUM>).