A packaging material forming apparatus

Abstract

A packaging material (dunnage) forming apparatus 10 for use with slitted paper, has a pair of feed rollers 60 driven to pull the paper a paper expander that opposes paper movement to create tension, t

Description

The present invention relates generally to a packaging material forming apparatus and a method of forming packaging material and finds particular, although not exclusive, utility in producing paper dunnage for use in filling voids inside packages. It is known to provide loose material, known as dunnage, for use as a cushioning / packing material around items placed in boxes to protect the items during transit. Such dunnage may be made of paper. In particular, paper dunnage may be formed from a feedstock of paper with a plurality of pre-formed transverse slits. The transverse slits are arranged in such a way that tension applied to the paper in a longitudinal direction (perpendicular to the slits) results in contraction of the paper in the transverse direction and expansion of the paper in the longitudinal direction and in a third dimension perpendicular to both the longitudinal direction and the transverse direction, thereby resulting in an overall increase in the volume occupied by the paper (referred to herein as “expanding” the paper). Due to the relatively thin strips of paper between the slits, excessive tension in the longitudinal direction will cause the paper to tear. In order to produce dunnage from this type of paper, it is desirable to be able to expand paper in an efficient way without tearing the paper. Known methods of expanding paper involve passing the paper through multiple sets of rollers, driven at different speeds such that tension is created in the paper between a first set of rollers driven at a slower speed and a second set of rollers driven at a higher speed. If the speed of the second set of rollers is too great, relative to the speed of the first set of rollers, the paper may tear. Equally, if the paper catches or snags on the first set of rollers, it may tear. Accordingly, there is a need for an apparatus that is capable of expanding paper having a plurality of transverse slits pre-formed therein with a reduced risk of tearing it. In a first aspect, the present invention provides a packaging material forming X J X X X CO CO CO apparatus for use with a feedstock of paper, the paper having a plurality of transverse slits pre-formed therein, the transverse slits arranged such that tension applied to the paper in a longitudinal direction causes contraction of the paper in a transverse direction and expansion of the paper in the longitudinal direction, and expansion in a third dimension perpendicular to both the longitudinal direction and the transverse direction, the apparatus comprising at least one pair of feed rollers driven to move the paper through the apparatus in a longitudinal direction, and a paper expander arranged such that the paper is pulled through it by the at least one pair of feed rollers, the paper expander configured to oppose the movement of the paper therethrough and thereby create tension in the paper, wherein the paper expander comprises a surface and an array of filaments arranged such that the filaments press against the surface, with the paper, in use, therebetween. The paper is typically provided on a roll with a continuous length which is substantially longer than the paper’s width. As used herein, the term “longitudinal direction” refers to a dimension oriented parallel to the paper’s continuous length, and “transverse direction” refers to a dimension oriented perpendicular to the longitudinal direction and parallel to the paper’s width. A transverse slit is a slit that extends transversely across the paper (i.e. having a longest dimension in the transverse direction). In this way, tension is created in the paper between the paper expander and the feed rollers as a result of the frictional forces exerted thereon by the surface and the filaments as it passes therebetween. In other words, the paper expander holds back the paper such that the speed at which it passes through the paper expander is reduced relative to that at which it is pulled through the feed rollers. This tension causes the slits in the paper to open up and the paper to stretch in the longitudinal direction. As it stretches in the longitudinal direction, it contracts in the transverse direction and its thickness increases, resulting in an overall volumetric expansion. However, the risk of the paper snagging and tearing as it passes between the surface and the filaments is minimised as flexing of the filaments may allow for the gap between the filaments and the surface to increase slightly and release any paper caught therebetween. Moreover, the frictional forces may not be dependent on the speed of the paper passing between the filaments and the surface and so variations in the speed at which paper is fed through the apparatus may be less likely to result in the paper being torn. The expanded paper may be dispensed from the apparatus as a continuous length of expanded paper or in discrete lengths, ready to be used straight away as dunnage. In the following discussion, the terms “upstream” and “downstream” may be used to refer to the movement of the paper through the apparatus. “Upstream” may be in a direction of paper travel, towards the roll of paper (feedstock). “Downstream” may be in a direction of paper travel, towards the dispensing point. It is to be understood that a filament may be a long, thin element. For example, a filament may be a bristle of a brush. The filaments may be resiliently deformable. That is, they may bend or flex under the influence of an applied force and return to their original shapes when the force is removed, such that their longitudinal axes are the same before the force is applied and after the force has been removed. The filaments may be made from a plastics material, such as nylon or polyester, metal wire, a natural fibre, such as animal hair or bamboo, and / or any other suitable material. The filaments may be parallel to one another. That is, their longitudinal axes may be parallel. Here, parallel may mean approximately parallel. The filaments may be fixed relative to the surface, at any point along their lengths, including one end. For instance, they may be attached to a rail immediately adjacent the curved surface. Portions of the filaments, distal from the point at which they are fixed, may be arranged to press against the curved surface. For example, the ends distal from their fixing points may press against die surface, wherein the ends are downstream of their fixing points relative to the movement of paper through the apparatus. In this way, the distal ends of the filaments may engage with the slits in the paper and help to open them up. The array of filaments may be a substantially linear array. The longitudinal axes of the filaments may be approximately parallel to the longitudinal direction of the paper, in use. In this way, there is a reduced risk that an end of a filament may get caught in one of the slits in the paper and cause snagging or tearing of the paper. The filaments may be formed rectilinear along their longitudinal lengths, but after being fixed to the apparatus may be urged into contact with die surface thus bending them, so that they are slightly curved. Where the longitudinal axis of a filament is curved, the longitudinal axis being approximately parallel to the longitudinal direction of die paper may mean that the longitudinal axis is approximately parallel to the longitudinal direction of the paper in a part of the filament where it presses against the paper. The surface may be curved. In particular, the surface may be a cylindrical surface and, more particularly, may be defined by the set of lines parallel to the transverse direction that pass through a curve in the plane perpendicular to the transverse direction. That is, the surface may have no curvature in the transverse direction. The surface may comprise sheet metal. In this way, the paper may at least partially “wrap around” the surface, thereby increasing the contact area, and the frictional force, between the paper and the surface. Other types of curved surface are contemplated, such as a convex spherical surface. The packaging material forming apparatus may further comprise a cutting mechanism located downstream of the feed rollers, the cutting mechanism configured to cut paper, expanded by the paper expander, in use, into discrete lengths. In this way, the apparatus may produce dunnage that is ready to use without needing to be cut. The cutting mechanism may comprise a pair of blades, such as a pair of reciprocating blades, a pair of rotary blades or a fixed blade and reciprocating blade. Alternatively, the cutting mechanism may comprise a further set of rollers, downstream of the feed rollers, wherein the feed rollers are driven to rotate in a stop-start manner while the further set of rollers are driven to rotate at a constant speed, such that the paper is tom between the two sets of rollers each time the feed rollers stop rotating. However, any appropriate mechanism for cutting paper as known in the art may be used. The packaging material forming apparatus may further comprise a feedstock support stand configured to rotatably support a roll of paper thereon. In this way, paper may be fed through the apparatus from a roll supported on the feedstock support stand, which may be fixed relative to the paper expander so that the angle at which the paper enters the paper expander may be kept constant. The feedstock support stand may additionally comprise one or more guide rollers to aid in achieving this purpose. Rotatably supporting a roll of paper may mean supporting the roll of paper so that it is free to rotate about its central axis, but so that the central axis is fixed. The feedstock support stand may rotatably support the roll of paper in such a way that its central axis is aligned with the transverse direction. The feedstock support stand may further comprise an adjustable friction brake arranged to act on the roll and at least partially oppose the rotation thereof. In this way, tension may be increased in the paper between the roll and the paper expander, and uncontrolled rotation of the roll may be prevented (for example, if the feed rollers suddenly stop). It is to be understood that the apparatus may comprise a frame or support structure configured to support the feed rollers, paper expander and, where present, the cutting mechanism and / or the feedstock support stand in fixed positions relative to one another. Here, the fixed positions may be permanently fixed or may be adjustable / reconfigurable by a user. Furthermore, it is to be understood that the apparatus may comprise other components in addition to those mentioned above. For example, the apparatus may additionally comprise a power supply, a drive system for driving the rollers, cutting mechanism etc., a user interface or control panel and / or a receptacle in which to collect and / or store the dunnage produced by the apparatus. In a second aspect, the invention provides a method of forming packaging material comprising the steps of: providing the packaging forming apparatus according to the first aspect; providing a supply of paper of the type having a plurality of transverse slits pre-formed therein, the transverse slits arranged such that tension applied to the paper in a longitudinal direction causes contraction of the paper in a transverse direction and expansion of the paper in the longitudinal direction and in a third dimension perpendicular to both the longitudinal direction and the transverse direction; passing a free end of the paper through the paper expander and between the at least one pair of feed rollers; and operating the apparatus so that the paper is moved therethrough by the at least one pair of feed rollers and expanded as a result of tension applied in the longitudinal direction by the paper expander. The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings. Figure 1 is a schematic side view of part of a packaging material forming apparatus; Figure 2a is a plan view of expandable paper; and Figure 2b is a plan view of the paper of Fig 2a in an expanded form. The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein. Likewise, method steps described or claimed in a particular sequence may be understood to operate in a different sequence. Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein. It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. Similarly, it is to be noticed that the term “connected”, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression “a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Connected” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. For instance, wireless connectivity is contemplated. Reference throughout tins specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any one embodiment or aspect of the invention may be combined in any suitable manner with any other particular feature, structure or characteristic of another embodiment or aspect of the invention, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects. Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value. The use of the term “at least one” may mean only one in certain circumstances. The use of the term “any” may mean “all” and / or “each” in certain circumstances. The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching, the invention being limited only by the terms of the appended claims. Figure 1 is a side view of part of a packaging material forming apparatus 10. The apparatus 10 comprises a feedstock support stand 30; a paper expander comprising a curved surface 40 and an array of filaments 50; and a housing 80 containing a set of feed rollers 60 and a cutting mechanism 70. A feedstock of paper of the type having a plurality of pre-formed transverse slits, as described in more detail with reference to Figures 2a and 2b, is provided on a roll 20, supported on the feedstock support stand 30. The paper moves through the apparatus 10 from the roll 20, through the paper expander and into the housing 80, where it passes through the feed rollers 60 before being cut into discrete lengths by the cutting device 70 and subsequently dispensed. The movement of the paper through the apparatus 10 is driven by the feed rollers 60 and is in the direction indicated by the arrows 90 (the “downstream direction”). The feedstock support stand 30, the paper expander and the housing 80 may be arranged in or on a support structure, excluded from the Figure for the sake of clarity. The feedstock support stand 30 supports the roll of paper 20 such that it can rotate about its central axis, as indicated by the arrow “A”. Only an outline of the feedstock support stand 30 is shown in this Figure so as to avoid obscuring detail behind it. The feedstock support stand 30 comprises a guide roller 35 to guide the paper as it is pulled off die roll 20. The paper 22 leaving the roll 20 is shown as flat and unexpanded. However, it is to be appreciated that a certain amount of expansion may occur at this point due to tension caused by frictional forces opposing the rotation of the roll 20. After leaving the roll 20, the unexpanded / partially expanded paper 22 passes through the paper expander where it is fed between the surface 40 and the filaments 50. The surface 40 is formed from a curved sheet of material (i.e. having no curvature in the direction into / out of the page) so that the paper conforms to and at least partially wraps around the surface 40, thereby maximising contact area between the paper and the surface 40. The filaments 50 are fixed at their respective proximal ends 52 to a paper expander frame 45, which is attached to the surface 40 towards the upstream end thereof. The filaments 50 are formed straight and are resiliently flexible. As shown, they have been bent by the surface 40 so that parts of the filaments 50, including their respective distal ends 54 press against the surface 40. That is, the distal ends 54 are biased towards the surface 40. Consequently, the paper passing between the surface 40 and the filaments 50 is pinched therebetween. The resulting friction opposes the movement of the paper and creates tension in the paper between this “pinch point” and the feed rollers 60. Consequently, the paper downstream of the filaments 50 is expanded and increases in thickness, as shown in the area indicated by arrow 24. In order to reduce the risk of die paper being tom as it passes between the surface 40 and the filaments 50, the filaments 50 are oriented with their distal ends 54 downstream of their fixed (proximal) ends 52 and such that the part of the filaments 50 that press against the paper are approximately parallel to the direction in which the paper is moving. In other words, in the side view of Figure 1, the filaments 50 are approximately tangent to the curve of the surface 40 towards their distal ends 54. After leaving the paper expander and passing through the feed rollers 60, die expanded paper 24 passes through a cutting device 70, which cuts the expanded paper into discrete lengths 26, ready for use as dunnage. The cutting device 70 is depicted as a pair of blades but, as mentioned above, any appropriate cutting mechanism may be used. The protective housing 80 encloses the feed rollers 60 and cutting device 70 to prevent the risk of injury to a user. As with the feedstock support stand 30, only an outline of the housing 80 is shown so as to avoid obscuring details. It is to be understood that the different components of the apparatus 10 are not necessarily drawn to scale and the precise relative positions of the components may differ from those shown. For example, the distance between the feedstock support stand 30 and the filaments 50 may be much greater than distance between the filaments 50 and the feed rollers 60. Figure 2a shows a small portion of the paper 120 used as feedstock in the apparatus depicted in Figure 1. It is to be understood that the paper portion 120 depicted in this Figure is taken from a continuous length of paper with a longitudinal direction (i.e. the direction along its continuous length) oriented vertically, and a transverse (width-wise) direction oriented horizontally, as indicated by the arrows. The paper 120 has a plurality of slits pre-formed therein; the slits are all aligned with the transverse direction. The slits are arranged in rows such that the slits in any given row lie in a single straight line parallel to the transverse direction. The slits in a first row are shifted transversely relative to the slits in the adjacent row(s) so that the slits in the first row overlap the gaps between the slits in the adjacent row(s). The slits in one row are indicated by the reference numeral 125. The paper portion 120 has a length 1 in the longitudinal direction and a width w in the transverse direction, as indicated. Figure 2b shows the paper 220 after it has been expanded. The expansion of paper is the result of tension applied in the longitudinal direction. As shown in Figure 2b, the slits 125 have been opened up to form approximately hexagonal holes 225. The expanded paper portion 220 has a length 1’ that is greater than the length 1 of the unexpanded paper portion 120, and a width w’ that is smaller than the width w of the unexpanded paper portion 120. That is, the expanded paper 220 has stretched in the longitudinal direction and contracted in the transverse direction. It should be understood that, in order for the slits to open up and form the holes 225, the expanded paper 220 has also expanded / stretched in the direction perpendicular to both its length and width (i.e. in / out of the page). That is, its thickness has increased. As a result of this increase in length and thickness, the expanded paper 220 occupies a greater volume than the unexpanded paper 120. The relatively large volume occupied by paper expanded in this way makes it suitable for use as dunnage.

Claims

1. A packaging material forming apparatus for use with a feedstock of paper, the paperhaving a plurality of transverse slits pre-formed therein, the transverse slits arranged such that tension applied to the paper in a longitudinal direction causes contraction of the paper in a transverse direction and expansion of the paper in the longitudinal direction, and expansion in a third dimension perpendicular to both the longitudinal direction and the transverse direction, the apparatus comprising at least one pair of feed rollers driven to move the paper through the apparatus in a longitudinal direction, and a paper expander arranged such that the paper is pulled through it by the at least one pair of feed rollers, the paper expander configured to oppose the movement of the paper therethrough and thereby create tension in the longitudinal direction of the paper, wherein the paper expander comprises a surface and an array of filaments arranged such that the filaments press against the surface, with the paper, in use, therebetween.

2. The packaging material forming apparatus, according to claim 1, wherein the filaments are parallel to one another.

3. The packaging material forming apparatus, according to either one of claim 1 and claim 2, wherein the filaments have proximal and distal ends and the distal ends of the filaments press against the surface.

4. The packaging material forming apparatus, according to any one of the preceding claims, wherein the longitudinal axes of the filaments are approximately parallel to the longitudinal direction of the paper, in use.

5. The packaging material forming apparatus according to any one of the preceding claims, wherein the surface is curved.

6. The packaging material forming apparatus according to any one of the preceding claims, further comprising a cutting mechanism located downstream of the feed rollers, the cutting mechanism configured to cut paper, expanded by the paper expander, in use, into discrete lengths.

7. The packaging material forming apparatus according to any one of the precedingclaims, further comprising a feedstock support stand configured to rotatably support a roll of paper thereon.

8. A method of forming packaging material comprising the steps of: providing the packaging forming apparatus according to any one of the preceding claims; providing a supply of paper of the type having a plurality of transverse slits preformed therein, the transverse slits arranged such that tension applied to the paper in a longitudinal direction causes contraction of the paper in a transverse direction and expansion of the paper in the longitudinal direction, and expansion in a third dimension perpendicular to both the longitudinal direction and the transverse direction; passing a free end of the paper through the paper expander and between the at least one pair of feed rollers; and operating the apparatus so that the paper is moved therethrough by the at least one pair of feed rollers and expanded as a result of tension applied in the longitudinal direction by the paper expander.13

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