GB2323582A - Preparing wrapped item for heat shrinking - Google Patents

Abstract

To prepare a wrapped product-bearing tray for heat shrinking of the wrapping as it is conveyed towards the heating zone, the trailing end of the wrapping is gathered and tucked beneath the tray. This prevents distortion of the trailing end when the leading end of the wrapping enters the heating zone first. Gathering and tucking is effected by powered rollers 11, or powered sliding means, located beneath the tray. The rollers 11 may have raised circumferential rings about their peripheries to engage and gather the wrapping. The rollers may be driven to effect the gathering when the tray is temporarily halted by stop means 7 when the leading end of the tray is detected by a sensor 8.

Description

IMPROVEMENTS IN AND RELATING TO PACKAGING PROCESSES Field of the Invention This invention relates to improvements in and relating to packaging processes, in particular but not exclusively: food packaging processes; improvements in apparatus relating to packaging processes and improvements in methods of packaging items; and to improved methods of packaging bulky food items within standard trays and to packaged products resulting from such an improved method.

Background Art Known to the Applicant C V P Systems Plc and other companies in this field for example The OSSID (Registered Trade Mark) Corporation promote and sell flow-wrapping machines. These machines wrap various products for example consumable products located within trays of variable lengths. width and height.

Typically, the consumable product flow wrapping machines are adapted to "shrink-wrap" packaged food stuffs and comprise a standard conveyor feeder, a positive packaging system and an oven or "heat-tunnel" to shrink wrap the packaged foodstuff. The reader is directed towards UK patent application numbers 96 09066.7 and 96 09914.8 which elaborate in some more detail. the types of machinery that is currently available in the market place to either shrink-wrap and/or package foodstuffs.

Such machines used in the presentation of fresh or frozen foodstuffs, in particular, meat products, place the tray with the foodstuff in it within an open bag of clear plastics material which is typically "bead" or "fin" sealed to form a "bagged" product and shrunk-wrapped to produce an aesthetically pleasing finished packaged product, the top surface of which comprises a plastics material stretched tight around the peripheral edge of the tray like the skin of a drum, the seams of any seals appearing no where near the top surface of the finished packaged product (infra).

Alternatively, instead of using bags of clear plastics material, sheet plastics material can be used which is initially wrapped around the packaged product to form a tube around the product and the tube is then "bead" or "fin" sealed along its longitudinal axis using heat and pressure and the plastics "tube" is then cut at either end of the tray, these cuts being in a substantially orthogonal direction to the seal. These substantially orthogonal cut edges are usually cut and sealed simultaneously again, to produce a "bagged" product prior to being shrunkwrapped to produce the aesthetically pleasing finished packaged product.

Both of these methods are perfectly acceptable for trays where the contents of the tray reside below the plane swept out by the upper peripheral edge of the tray in its normal attitude of operation. This is because the substantially orthogonal seals in such "bagged" products reside very close to the leading and rearward edges of the tray respectively and hence when the tray enters the "heat-tunnel", even though the leading edge of the plastics material begins to shrink first, there is a minimal "creep" or "drag" of the rearward seal over the top surface of the tray ensuring that the seams of the rearward seal appears nowhere near the top surface of the finished shrunk-wrapped product.

Problems arise however when one wants to package for example, whole chickens or otherwise bulky materials in these standard trays. Such materials otherwise by-pass the plane swept out by the upper peripheral edge of the tray when the material sits within it. Irrespective of whether the eventual "bagged" product is formed from "bead" or "fin" sealing a bag of clear plastics material or cutting and sealing a "bead" or "fin" sealed "tube" the orthogonal seals of the plastics material bag will be a lot further away from the leading and rearward edges of the tray. In such a situation, as the leading edge of the tray enters the heat tunnel, to effect shrink-wrapping, the initial shrinking of the leading edge portion of the shrink-wrappable plastics material tends to drag the rearward portion of the plastics material bag and with it, the rearward orthogonal seal across the top face of the tray so that when the tray is completely shrunkwrapped, the rearward orthogonal seal appears on the top face of the finished product which is aesthetically unappealing to the buying consumer.

The invention seeks to overcome this problem and whilst it is embodied in several independent aspects, it will be apparent from this broad background review and the following specific description, that these aspects are so linked as to form part of the same inventive concept.

Summarv of the Invention According to a first aspect of the present invention, there is provided apparatus adapted to prepare product laden trays, sealed by shrink-wrappable plastics material for entry into a so-called "heat-tunnel" to effect shrink-wrapping; the apparatus comprising: a conveyor to move the sealed and laden but not yet shrink-wrapped trays through the apparatus and material-gathering means having a powered sliding and/or rollering action, and which in use - and with the tray located above the gathering means - gathers that portion of the plastics material that extends rearwardly of the tray (with respect to the direction of travel of the tray through the apparatus) and positively tucks this portion of the plastics material under the tray before the tray enters the shrink-wrapper.

Preferably, the apparatus further comprises stop means to temporarily halt the progress of the tray at a predetermined point along the conveyor to allow the action of the gathering means to function at substantially the same location of each respective tray as it passes.

More preferably still, the operative plane of the plastics material gathering means is raised relative to the rest of the conveyor system.

Preferably, the plastics material gathering means comprise rollers and the rollers are faced about their respective peripheries with diametrically raised portions, for example, "O"-rings.

Preferably, the apparatus includes within its scope apparatus substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.

Preferably, the invention also includes within its scope a flow wrapping apparatus for use in packaging, sealing and shrink-wrapping products incorporating the apparatus as specified above.

According to a second aspect of the present invention, there is provided a method of preparing product-laden trays sealed by shrink-wrappable plastics material, for entry into a so-called "heat-tunnel" to effect shrink-wrapping; the method comprising the steps of first moving the sealed and laden but not yet shrink-wrapped trays via a conveyor into a position in which each tray is successively located above a material-gathering means having a powered sliding and/or rollering action and then operating the gathering means to gather that portion of the plastics material that extends rearwardly of the tray (with respect to the direction of travel of the tray through the apparatus) to positively tuck the said portion under the tray before the tray enters the shrink-wrapper.

Preferably, the method further incorporates the step of stopping the progress of the tray at a predetermined point on the apparatus prior to gathering the plastics material and tucking it under the tray. Preferably, the invention includes within its scope, a method substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.

According to a third aspect of the present invention, there is provided a product that results from the method as specified above.

Brief Description of the Drawings Figure 1 illustrates a side view of a sealed product prior to entry into a shrinkwrapper - heat tunnel.

Figure 2 illustrates one embodiment of the present invention.

Description of the Preferred Embodiments Throughout this specification, the definition of the term "stop means" is intended to encompass literal stop members which are physical barriers to prevent the continuation of travel of an object by virtue of that object abutting the stop member and the term stop means is also intended to cover for example an electronic shut-down of for example a conveyor to effect the halt of objects on that conveyor without physically stopping them by placing a stop member in their path.

Figure illustrates a "bagged" product generally referenced 1. The "bagged" product comprises a bulky material 6 that sits within a tray 3. The product laden tray 3 being "bagged" by a clear shrink-wrappable plastics material 2.

The seals 4 of the shrink-wrappable material 2 being clearly illustrated.

The bulky nature of the product 6 has meant that the seals 4 have had to been made at a distance "X" from the leading and rearward lips of the tray 3 respectively. For non bulky products, this distance "X" would be a lot less.

The product illustrated in Figure 1 is ready for entry into a so-called "heattunnel" which will effect shrink-wrapping of the plastics material 2. However.

if the "bagged" product generally referenced 1 were to enter the "heat-tunnel", via the leading lip 5, the front portion of the plastics material 2 would begin shrinking more rapidly than the rearward section. This would drag the rearward seam up and over the rearward lip of the tray shortening the rearward distance The apparatus illustrated in Figure 2 attempts to alleviate this problem. As can be seen in Figure 2, the apparatus is adapted to prepare product laden trays that have been "bagged" for shrink-wrapping without this drag or creep phenomenon. The apparatus comprises a conveyor 9 to move the sealed and laden but not yet shrink-wrapped trays generally referenced 1 (see Figure 1) through the apparatus together with material-gathering means, in this particular case, a number of rollers 10 some of which are faced about their respective peripheries with diametrically raised portions that in this particular embodiment comprise "O"-rings. The apparatus further comprises a stop means 7 to temporarily halt the progress of the tray at a predetermined point along the conveyor 9 to allow the action of the gathering means to function at substantially the same location of each respective product laden tray 1 as it passes.

The plastics material gathering means 11 as a result of the "O"-rings is raised relative to the rest of the conveyor system 9 which essentially comprises a number of motorised rollers 10. As the "bagged" product 1 enters the conveyor 9, a product sensor 8 "looking for" "bagged" products 1, once one has been detected, automatically transmits a signal to the stop member 7 which is vertically raised in between a gap between consecutive rollers 10. The leading lip 5 of the "bagged" product 1 abuts the stop member 7 and the motion of the "bagged" product 1 is temporarily halted. The location of the rollers 11 with the diametrically raised portions and the location of the stop member 7 ensure that the front portion of the underside of the "bagged" product 1 is no longer in contiguous relationship with the roller(s) 10 directly beneath it. The electrically driven rollers on the conveyor 9 all continue to rotate in a clockwise manner yet it is only the rollers 11 that are in contact with the underside of the "bagged" product 1. These rollers 11, gather that portion of the plastics material 2 denoted by the distance "X" and positively tucks this portion of the plastics material to under the tray 3 before the stop member 7 is lowered allowing the "bagged" product 1 to then continue along the conveyor before the product enters the "heat-tunnel".

The apparatus illustrated in Figure 2 is so sized and shaped as to allow it to be "slotted-in" or otherwise form part of a flow-wrapping apparatus for use in packaging, sealing and shrink-wrapping "bagged" products 1.

Of course this embodiment is non limiting and alternative embodiments that are not illustrated will now be described.

For example, the rollers 11 could be replaced by some form of sliding mechanism instead of a rollering mechanism as illustrated in Figure 2. Such sliding action would achieve the same effect of positively tucking the rearward portion of the plastics material 2 defined by the distance "X" under the tray 3.

In alternative embodiments not illustrated, the apparatus could further include a "spiked" roller 11 which will also achieve the same aim. The stop member 7 need not necessarily be a physical stop member and the product laden trays 1 could also be brought to a halt temporarily by simply switching off the motorised rollers and allowing at least one roller 11 to function independently of the pothers to achieve the same tucking action before the rest of the rollers engage and allow the product laden tray 1 to continue along through the apparatus.

Although the apparatus just described is believed, by the inventor to be both new and inventive, the method of preparing product-laden trays for sealing by shrink-wrapping apparatus is also believed to be new. The method steps for such a process using the apparatus illustrated in Figure 2, comprised the steps of first stopping the progress of the tray at a predetermined point on the apparatus via the use of the stop member 7 and then operating the gathering means, in this case, the rollers 11 to gather that portion of the plastics material that extends rearwardly of the tray (with respect to the direction of travel of the tray through the apparatus) to positively tuck the said portion under the tray before the stop member is removed to allow the tray to continue along the apparatus. In alternative embodiments, the stop member need not necessarily be present and could be replaced by a single roller 11 that rotates far more rapidly than any of the other rollers achieving the same effect so the overall process need not necessarily incorporate a temporary halt in the progress of the tray along the conveyor.

Where this specification has described the use of "O"-rings, a preferred embodiment of the preferred invention employs the use of ten such "O"-rings that are of 2mm section, there being ten rollers employed in the apparatus in total.

Claims (10)

Claims

1. Apparatus adapted to prepare product laden trays, sealed by shrink wrappable plastics material for entry into a so-called "heat-tunnel" to effect shrink-wrapping; the apparatus comprising: a conveyor to move the sealed and laden but not yet shrink-wrapped trays through the apparatus and material-gathering means having a powered sliding and/or rollering action, and which in use - and with the tray located above the gathering means - gathers that portion of the plastics material that extends rearwardly of the tray (with respect to the direction of travel of the tray through the apparatus) and positively tucks this portion of the plastics material under the tray before the tray enters the shrink-wrapper.

2. Apparatus as claimed in Claim 1, characterised in that the apparatus further comprises stop means to temporarily halt the progress of the tray at a predetermined point along the conveyor to allow the action of the gathering means to function at substantially the same location of each respective tray as it passes.

3. Apparatus as claimed in Claim 1 or Claim 2, characterised in that the operative plane of the plastics material gathering means is raised relative to the rest of the conveyor system.

4. Apparatus as claimed in any of the preceding Claims, characterised in that the plastics material gathering means comprise rollers and the rollers are faced about their respective peripheries with diametrically raised portions, for example, "O"-rings.

5. Apparatus substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.

6. A flow wrapping apparatus for use in packaging, sealing and shrink wrapping products incorporating the apparatus as claimed in any of the preceding Claims.

7. A method of preparing product-laden trays sealed by shrink-wrappable plastics material, for entry into a so-called "heat-tunnel" to effect shrink wrapping; the method comprising the steps of first moving the sealed and laden but not yet shrink-wrapped trays via a conveyor into a position in which each tray is successively located about a material-gathering means having a powered sliding and/or rollering action and then operating the gathering means to gather that portion of the plastics material that extends rearwardly of the tray (with respect to the direction of travel of the tray through the apparatus) to positively tuck the said portion under the tray before the tray enters the shrink-wrapper.

8. A method of preparing product-laden trays as claimed in Claim 7 characterised in that the method further incorporates the step of stopping the progress of the tray at a predetermined point on the apparatus prior to gathering the plastics material and tucking it under the tray.

9. A method substantially as herein described with reference to and as illustrated by any appropriate selection or combination of Figures 1 and 2 of the accompanying drawings.

10. A product that results from the method as claimed in Claims 8 and 9.