Flow wrapper with adjustable gate and related methods

Abstract

The invention relates to a flow wrapper with a transport mechanism, a former, and a sealing mechanism. The flow wrapper is characterized by an adjustable gate before the fin seal mechanism. The adjust

Description

Field of the invention The invention pertains to the field of flow wrappers. Background and prior art known to the Applicant(s) In the field of packaging, flow wrapping is a common method used to package a wide variety of products. This method involves the use of a continuous sheet of flexible packaging wrapping material that is wrapped around the product to form a package. The wrapping material is typically fed from a roll and formed into a tube around the product, with the edge regions of the wrapping material being sealed together to form a fin which is generally located below the resulting package and sometimes referred to as the bottom fin seal. This process is typically carried out by a flow wrapper, which includes a transport mechanism for carrying the items to be packaged, and a former for shaping the packaging material into a tube. One of the challenges in flow wrapping is the need to accommodate different sizes and shapes of products. This often requires relatively complex adjustments to the flow wrapper, which can be time-consuming and may result in downtime. Another challenge is the need to maintain a consistent tension on the packaging material as it is formed into a tube and sealed. If the tension is too high, it can cause the packaging material to tear or the seal to fail. On the other hand, if the tension is too low, it can result in a loose package. With this in mind generally, all the components of the flow wrapper are carefully adjusted prior to a particular packaging run. Therefore, there is a need for improvements in flow wrapping technology to address these and other challenges. In particular, there is a need to provide a more straightforward approach to varying the sizes of the resulting tube in order to provide a tighter or looser fit even during the operation of the flow wrapper. SUMMARY OF THE INVENTION In accordance with embodiments, a flow wrapper is provided that includes a transport mechanism, a former, and a sealing mechanism. The transport mechanism carries items in sequence for wrapping in a wrapping material. The former receives the wrapping material and shapes it into a tube whilst receiving items and wrap them for subsequent handling. The sealing mechanism seals the outside edge regions of the wrapping material together to form a sealed fin. The flow wrapper is characterized by an adjustable gate prior to the fin seal mechanism. The adjustable gate incorporates two or more spaced apart guiding members against which the outside edge regions of the wrapping film run. The space between the guiding members is adjustable. In accordance with other embodiments, a method of packaging items is provided. The method includes transporting items in sequence to a flow wrapper, providing wrapping material, forming a tube with the wrapping material, and sealing the wrapping material's outside edge regions together to form a fin. The method is characterized by presenting the outside edge regions to an adjustable gate prior to the sealing step and adjusting the spacing between guiding members of the adjustable gate while the outside edge regions of the wrapping film run against the guiding members. This allows the volume of the resulting tube and the length of the resulting fin to be adjusted. In a first broad independent aspect, the invention provides a flow wrapper comprising: a transport mechanism configured to carry items in sequence for wrapping in a wrapping material; a former for receiving the wrapping material and shaping the wrapping material into a tube; the tube being configured to receive items and thereby wrapping them for subsequent handling; the wrapping material having two oppositely disposed outside edge regions which are brought together by the former as the wrapping material is drawn through the former; a sealing mechanism is provided to seal the wrapping material's outside edge regions together to form a sealed fin; characterised in that the flow wrapper incorporates an adjustable gate prior to the fin seal mechanism; the adjustable gate incorporating two or more spaced apart guiding members against which the outside edge regions of the wrapping film run, when the flow wrapper is in use; the space between the guiding members being adjustable. This configuration is particularly advantageous for controlling the film or wrapping material flow in a preferred embodiment when the flow wrapper is a horizontal form fill and seal (so called HFFS) machine. In preferred embodiments, adjusting the gate width, changes the fin size of the finished pack. This inherently changes the amount of space within the pack. This allows the pack to have a greater or lower level of tightness. In other words, the flow wrapper according to this first broad aspect may incorporate a pack tightener module. In a subsidiary aspect, the adjustable gate is either pre-set for a particular spacing between the guiding members or is adjustable whilst the flow wrapper is operating. This provides for versatile adjustments of the volume of the produced packs. In a further subsidiary aspect, the space between the guiding members is adjustable by at least one adjustment mechanism. This configuration is particularly advantageous as it allows improved control of the packaging size and fit even during the operation of the flow wrapper. In a further subsidiary aspect, the adjustment mechanism is manually adjustable to increase and / or decrease the space between the guiding members. This provides a simple solution which marks a complete departure from the complexity of prior art mechanisms. In a further subsidiary aspect, the adjustment mechanism is driven to increase and / or decrease the space between the guiding members. This is particularly advantageous to, in certain embodiments, allow remote control of the adjustment. In a further subsidiary aspect, the driven adjustment mechanism is electrically powered and comprises one or more mechanical components to facilitate the incremental displacement of one or more guiding members; whereby the space between the guiding members may be incrementally adjusted. In a further subsidiary aspect, the guiding members are displaceable at the same time and by the same amount in order to retain their position relative to the centre longitudinal axis of the flow wrapper. In a further subsidiary aspect, the adjustable gate comprises a support structure and one or more of the guiding members are mounted thereon for displacement relative to the support structure. This configuration is particularly advantageous for precise adjustments of the sizes of the tube and consequently the resulting size of the packs. In a further subsidiary aspect, the or each movable guiding member is mounted onto the support structure via one or more guide rails in order to facilitate the linear lateral displacement of the or each guiding member relative to the longitudinal direction of the flow wrapper. This optional configuration provides even further versatility to previously described aspects. In a further subsidiary aspect, the adjustable gate is located in a fixed position between the exit from the former and the sealing mechanism. This provides an increase in reliability of operation and ease of access. In a further subsidiary aspect, the position of the adjustable gate is adjustable in the longitudinal direction of the flow of wrapping material through the flow wrapper. This optional configuration provides even further versatility to previous aspects. In a further subsidiary aspect, the guiding members of the adjustable gate are brought in closer proximity to one another to increase the volume of the packaging structure and reduce the size of the sealing fin. In a further subsidiary aspect, the spacing between guiding members is increased to reduce the volume of the packaging structure and increase the size of the sealing fin. In a further broad aspect, the invention provides a method of packaging items, comprising the steps of : transporting items in sequence to a flow wrapper; providing wrapping material; forming a tube with the wrapping material; the wrapping material having two oppositely disposed outside edge regions which are brought together by a former as the wrapping material is drawn through the former; sealing the wrapping material's outside edge regions together to form a fin; characterised in that the method comprises the further step of presenting the outside edge regions to an adjustable gate prior to the sealing step; and adjusting the spacing between guiding members of the adjustable gate whilst the outside edge regions of the wrapping film run against the guiding members, when the flow wrapper is in use; whereby the volume of the resulting tube and the length of the resulting fin may be adjusted. In a subsidiary aspect, the method comprises the step of adjusting the spacing between the guiding members whilst the flow wrapper is operating. In a further subsidiary aspect, the method comprises the further step of providing an adjustment mechanism and adjusting the space between the guiding members. In a further subsidiary aspect, the method comprises the further step of manually adjusting the adjustment mechanism to increase and / or decrease the space between the guiding members. In a further subsidiary aspect, the method further comprises the step of driving the adjustment mechanism to increase and / or decrease the space between the guiding members. In a further subsidiary aspect, the method comprises the step of electrically powering the adjustment mechanism and providing one or more mechanical components to facilitate the incremental displacement of one or more guiding members; and incrementally adjusting the space between the guiding members. In a further subsidiary aspect, the method further comprises the steps of displacing the guiding members at the same time and by the same amount in order to retain their position relative to the centre longitudinal axis of the flow wrapper. In a further subsidiary aspect, the method further comprises the step of providing a support structure for the adjustable gate and mounting one or more of the guiding members thereon and displacing one or more of the guiding members relative to the support structure. In a further subsidiary aspect, the method further comprises the step of displacing the or each movable guiding member relative to the support structure via one or more guide rails in order to facilitate the linear lateral displacement of the or each guiding member relative to the longitudinal direction of the flow wrapper. In a further subsidiary aspect, the method provides the step of locating the adjustable gate in a fixed position between the exit from the former and the sealing mechanism. In a further subsidiary aspect, the method further comprises the step of adjusting the position of the adjustable gate in the longitudinal direction of the flow of wrapping material through the flow wrapper. In a further subsidiary aspect, the method further comprises the step of bringing the guiding members in closer proximity to one another to increase the volume of the tube or packaging structure and reduce the size of the sealing fin; and / or further comprising the step of increasing the spacing between guiding members to reduce the volume of the tube or packaging structure and increase the size of the sealing fin. BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a perspective view of a flow wrapper in accordance with an embodiment of the invention. Figure 2 shows a side elevation of the adjustable gate in accordance with an embodiment of the invention. Figure 3 shows a further side elevation of the adjustable gate in an additional configuration and in accordance with a further embodiment of the invention. Figure 4 shows a further embodiment of an adjustable gate where the adjustment is driven by an electric motor. Figure 5 shows in perspective view a configuration of the wrapping material and interacts with the adjustable gate where the respective guiding members or plates are located in relatively close proximity to one another. Figure 6 also schematically shows the interaction of the edge regions and their interaction with the adjustable gate in a configuration where the guide members are relatively spaced apart. DETAILED DESCRIPTION OF THE FIGURES As schematically shown in figure 1, the flow wrapping process typically begins with the transportation of items such as item 2 which are brought in sequence to a flow wrapper generally referenced 1. This is accomplished by a conveyor belt system 3 or such transportation mechanism that moves items one after the other towards the flow wrapper. The conveyor belt system is typically powered by an electric motor, which ensures a smooth and consistent movement of items. Next, the wrapping material 4 is provided. This can be any suitable material such as plastic film, paper or aluminium foil. The wrapping material is stored in a roll 5 and is unrolled as needed. The unrolling of the wrapping material is controlled by a mechanical system (not shown) that ensures the right amount of material is provided. The provided wrapping material is then formed into a tube 6. This is done by a shaping mechanism, such as a former 7, which often shapes the wrapping material into a cylindrical form although other tubular geometries may also be produced such as tubes which are square or rectangular in cross-section. The former is designed to accommodate the specific dimensions of the items to be packaged. The two oppositely disposed outside edge regions of the wrapping material are then brought together. This is done by the former, which folds the wrapping material in such a way that the two outside edge regions are overlayed. The overlaying edge regions are then sealed together to form a fin which is often referred to as a bottom fin. The sealing is typically carried out by a sealing mechanism 8, such as a heat sealer, which applies heat and pressure to the edge regions causing them to fuse together. In accordance with an embodiment, prior to the outside edge regions of the wrapping material being sealed together, the edge regions are presented to a variable width gate 9. The variable width gate 9 is an adjustable guiding system that controls the tightness of the tube of the wrapping material as it is sealed. The gate is adjusted by an actuator, which changes the space between the guiding members of the gate. Gate 9 will be described in further detail in subsequent figures. The outside edge regions of the wrapping material run against the guiding members of the gate as the space between them is adjusted. This is done to ensure that the wrapping material is properly aligned and that the seal is formed correctly. The guiding members are designed to guide the wrapping material smoothly and accurately. The adjustable gate allows the volume of the resulting tube and the length of the resulting fin to be adjusted. Figure 2 shows in further detail the adjustable gate 9 which may be employed in a flow wrapper 1. The flow wrapper incorporates a support structure generally referenced 10 which may be a plate onto which guiding members 11 and 12 are mounted. The relative position of the guiding members is adjustable, they may be in the most spaced apart configuration in figure 2 whilst these may be brought into close proximity as shown in figure 3. In this embodiment, the guiding members are joined together by an axle 13 with respective threaded portions 14 and 15. The guiding members 11 and 12 comprise receivers 16 and 17 which have threaded tunnels or recessed portions for interacting with the respective threaded portions of the axle. At the distal extremity of the axle, an adjustment handle 18 is provided and has a number of recesses about its perimeter for ease of handling. An operator can thus rotate the handle and by so doing cause the guiding elements or plates 11 / 12 to displace in unison towards or away from one another to allow the adjustment of the gate width 20. Plates 11 and 12 are secured to the support structure 10 by one or more protrusions or fasteners (not shown in the figures) which engage in respective longitudinal recesses 21 and 22. The support structure has a U-shaped upper cut-out portion with a lower surface 23. Instead of recesses 21 and 22, guide rails 21 and 22 may be provided to facilitate the lateral displacement of the guiding members. In the view shown on the right side of the main view of the adjustable gate in figure 2,the gate is shown as mounted in a vertical direction. Optionally, in accordance with any of the embodiments described herein, the gate may be mounted at an angle. For example, the angled plane of the adjustable gate may be between 1 and 45 degrees relative to the vertical axis. Furthermore, whilst the handle may be located on a particular side of the flow wrapper, it may equally be located on the opposite side. Thus, the adjustable mechanism may be manually operated from either the righthand side or the lefthand side of the flow wrapper dependent upon the desired configurations. Furthermore, in an alternative embodiment, the mechanism may be powered and located inside the machine rather than being accessible from the lefthand or righthand side. As shown in figure 3, a minimum gate width 24 is shown where a gap remains. In preferred embodiments, the guiding members are configured to be adjusted laterally whilst at the same time being prevented from abutting one another thus providing a minimum gate width 36 as shown in figure 3. A number of apertures are provided in the support member for securely fastening the support member onto the flow wrapper dependent upon the desired location for the adjustable gate. In a further embodiment, as show in figure 4, the adjustable gate may be adjusted by powering the displacement of the axle 26. In this embodiment, an electrically powered motor 27 may displace the axle in increments. One or two gears 28 and 29 may be provided between the electric motor and the axle as appropriate. A belt (or chain) 30 may be included between pulleys (or gears) 28 and 29. A bearing block 31 supports the end of the shaft 28. Figures 5 and 6 schematically illustrate the interaction between the plates of the adjustable gate and the respective end regions 32 and 33 of the wrapping material. In figure 5, the space between plates 11 and 12 of the gate are relatively close in proximity which provides for a resulting smaller fin size and more space inside the pack. By contrast, by increasing the space between plates 11 and 12, as shown in figure 6, a larger fin size results together with a reduction of the space inside the pack. As can clearly be seen, the ends formed by end regions 34 and 35 are of a much larger size than the fin size achieved in the configuration of figure 5 where the edge of the regions 32 and 33 are of a smaller size. Furthermore, the resulting pack in figure 6 is much tighter than the pack obtained in the embodiment of figure 5. 29 08 25

Claims

1. A flow wrapper comprising:a transport mechanism configured to carry items in sequence for wrapping in a wrapping material;a former for receiving the wrapping material and shaping the wrapping material into a tube; the tube being configured to receive items and thereby wrapping them for subsequent handling; the wrapping material having two oppositely disposed outside edge regions which are brought together by the former as the wrapping material is drawn through the former;a sealing mechanism is provided to seal the wrapping material's outside edge regions together to form a sealed fin;characterised in that the flow wrapper incorporates an adjustable gate which is separate from the former and which is provided prior to the fin seal mechanism; the adjustable gate incorporating two spaced apart guiding plates, wherein the guiding plates are operatively coupled to an axle comprising two threaded portions, each of which engages a corresponding threaded tunnel in a guiding plate; whereby rotation of the axle causes the guiding plates to be displaced in unison towards or away from one another in a direction substantially perpendicular to the direction of flow and wherein the guiding plates are displaceable between a first position where a gap remains between them whilst in close proximity to one another and a second position when they are further spaced apart.

2. The flow wrapper of claim 1, wherein said axle is manually rotatable to increase and / or decrease the space between the guiding plates.

3. The flow wrapper of claim 1, further comprising a driven adjustment mechanism which is electrically powered.

4. The flow wrapper of any one of the preceding claims, wherein the adjustable gate comprises a support structure and one or more of the guiding plates are mounted thereon for displacement relative to the support structure.

5. The flow wrapper of claim 4, wherein the or each movable guiding plate is mounted onto the support structure via one or more guide rails in order to facilitate the linear lateral displacement of the or each guiding plate relative to the longitudinal direction of the flow wrapper.29 08 256. The flow wrapper of any one of the preceding claims, wherein the adjustable gate is located in a fixed position between the exit from the former and the sealing mechanism.

7. The flow wrapper of any one of claims 1 to 6, wherein the position of the adjustable gate is adjustable in the longitudinal direction of the flow of wrapping material through the flow wrapper.

8. A method of packaging items, comprising the steps of :transporting items in sequence to a flow wrapper; providingwrapping material;forming a tube with the wrapping material; the wrapping material having two oppositely disposed outside edge regions which are brought together by a former as the wrapping material is drawn through the former;sealing the wrapping material's outside edge regions together to form a fin;characterised in that the method comprises the further step of presenting the outside edge regions to an adjustable gate prior to the sealing step; the adjustable gate being separate from the former and incorporating two spaced apart guiding plates, wherein the guiding plates are operatively coupled to an axle comprising two threaded portions, each of which engages a corresponding threaded tunnel in a guiding plate; whereby rotation of the axle causes the guiding plates to be displaced in unison towards or away from one another in a direction substantially perpendicular to the direction of flow and wherein the guiding plates are displaceable between a first position where a gap remains between them whilst in close proximity to one another and a second position when they are further spaced apart; and adjusting the spacing between guiding plates of the adjustable gate whilst the outside edge regions of the wrapping material run against the guiding plates, when the flow wrapper is in use; whereby the volume of the resulting tube and the length of the resulting fin may be adjusted.

9. The method of claim 8, comprising the further step of manually rotating the axle to increase and / or decrease the space between the guiding plates.29 08 2510. The method of either claim 8 or claim 9, further comprising the step of driving the rotation of the axle to increase and / or decrease the space between the guiding plates.

11. The method of claim 10, further comprising the step of electrically driving the rotation of the axle.

12. The method of any one of claims 8 to 11, providing a support structure for the adjustable gate and mounting one or more of the guiding plates thereon and displacing one or more of the guiding plates relative to the support structure.

13. The method of claim 12, further comprising the step of displacing the or each movable guiding plates relative to the support structure via one or more guide rails in order to facilitate the linear lateral displacement of the or each guiding plate relative to the longitudinal direction of the flow wrapper.

14. The method of any one of claims 8 to 13, locating the adjustable gate in a fixed position between the exit from the former and the sealing mechanism.

15. The method of any one of claims 8 to 14, further comprising the step of adjusting the position of the adjustable gate in the longitudinal direction of the flow of wrapping material through the flow wrapper.

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