Patent Application
20240383713
The preferred embodiments of the present invention relate to systems and methods for improved expansion of an expandable slit sheet material.
The preferred embodiments improve upon and overcome a number of issues in relation to existing background art.
Among other things, the preferred embodiments of the present invention substantially improve upon that shown in the present inventor's prior U.S. Pat. No. 5,688,578, entitled Slit Sheet Packing Material, which teaches the use of an expansion device that uses a pair of hook and loop rollers, using the hook portion of material such as sold under the trademark Velcro®. In this background patent, the pair of rollers are vertically aligned in the machine direction (i.e., the expansion direction of the expanded slit sheets) and spaced apart such that the rollers grab and pull through the expanded slit sheet by grabbing both sides of the expanding slit sheet. It has now been found by the present inventor that this method, particularly for a single slit sheet expansion, crushes the sheet as it is pulled through. This crushing reduces the overall effectiveness of the expanded slit sheet, such as, e.g., reducing its effectiveness as a cushioning material. It has now also been determined by the present inventor, through testing, that although the resultant crushing was not previously evident, it does occur and reduces the overall effectiveness of the expanded slit sheet as a cushioning material. The disclosure of U.S. Pat. No. 5,688,578 is incorporated herein by reference, as though recited in full.
The present invention is also a substantial improvement over the present inventor's prior U.S. Patent Publication No. 2017/0203866 that involves a pair of opposing hook rollers that expand a layered pair opposing slit sheets that together pass between the opposing hook rollers, wherein the opposing hook rollers are, similar to the above U.S. Pat. No. 5,688,578, vertically aligned at the same location in the machine direction (i.e., in the expansion direction of the expanded slit sheets).
The preferred embodiments provide substantial improvements over the above and/or other background art, and overcome a number of issues in relation to the above and/or other background art.
The preferred embodiments of the present invention overcome various shortcomings in the background art.
In accordance with some illustrative embodiments of the present invention, a novel expandable slit paper expansion device design is provided that, among other things, avoid complications of prior systems and eliminates the crushing effect of the rollers. Among other things, the preferred embodiments provide a unique structure that provides a novel “S” shape path of the expandable slit sheet paper, such that the expandable slit sheet paper is tortuously weaved between at least two expansion rollers without being compressed there-between, in a manner that the expandable slit sheet paper follows along surfaces of the expansion rollers without pinching or compression that occurs in the background art.
Among other things, the present invention provides a novel and advantageous configuration that, e.g., improves handling of expandable slit sheet paper and avoids damage, such as, e.g., crushing or the like.
According to some preferred embodiments of the invention, a system having an expander for expanding and feeding an expandable slit sheet material with reduced damage to the expandable slit sheet material is provided that includes: a) at least one first roller for feeding the expandable slit sheet material, the at least one first roller being adapted to rotate to move the expandable slit sheet material downstream at a first reduced rate; b) at least two expansion rollers located downstream from the at least one first roller which receive the expandable slit sheet material from the at least one first roller, the at least two expansion rollers being adapted to rotate to move the expandable slit sheet material further downstream at a second rate that is faster than the first reduced rate, such as to cause the expandable slit sheet material to expand due to the second rate being faster than the first reduced rate; c) the at least two expansion rollers including two adjacent expansion rollers arranged to adjacent one another, at least one of the two adjacent expansion rollers including a plurality of hooks distributed around a periphery thereof which are configured to engage slits of the expandable slit sheet material; d) the two adjacent expansion rollers being separated from one another by a distance greater than a thickness of the expandable slit sheet material in an expanded state, such that the two adjacent expansion rollers do not concurrently press against opposite sides of the expanded slit sheet material at a same longitudinal position of the expanded slit sheet material so that the two adjacent expansion rollers avoid damaging the expanded slit sheet material.
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that a portion of the path of the expanded slit sheet material passing around the two adjacent expansion rollers is S-shape, with the path curving in a first direction around a periphery of one of the two adjacent expansion rollers and then in a second direction that is away from the first direction around a periphery of the other of the two adjacent rollers.
According to some exemplary embodiments, the system is an envelope manufacturing system.
According to some exemplary embodiments, the system is configured to manufacture an envelope having the expanded slit sheet material in a peripheral wall of the envelope for protection of an item within the envelope.
According to some other preferred embodiments, a method of using the system of according to the above preferred embodiment(s) is performed that includes: manufacturing a plurality of envelopes each having expanded slit sheet material in a peripheral wall of the envelope for protection of items within the envelope.
According to some exemplary embodiments, the system is a wrapping system.
According to some exemplary embodiments, the system is configured to provide wrapping of an item within the expanded slit sheet material for protection of the item.
According to some other preferred embodiments, a method of using the system according to the above preferred embodiment(s) is performed that includes: wrapping an item with the expanded slit sheet material for protection of the item.
According to some exemplary embodiments, the system further includes a controller for controlling the rotation of the at least two expansion rollers.
According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 140% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 160% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 180% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 200% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 240% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 260% of the thickness. According to some exemplary embodiments, the two adjacent expansion rollers are separated from one another by a distance greater than the thickness of the expandable slit sheet material and up to 300% of the thickness.
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material contacting each of the two adjacent expansion rollers around respective arcs of at least 40 degrees around each of the adjacent expansion rollers. According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material contacting each of the two adjacent expansion rollers around respective arcs of at least 60 degrees around each of the adjacent expansion rollers. According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material contacting each of the two adjacent expansion rollers around respective arcs of at least 90 degrees around each of the adjacent expansion rollers. According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing the one of the two adjacent expansion rollers includes the expanded slit sheet material contacting the one of the two adjacent expansion rollers around an arc of between 180 degrees and 270 degrees. According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing the other of the two adjacent expansion rollers includes the expanded slit sheet material contacting the other of the two adjacent expansion rollers around an arc of between 180 degrees and 270 degrees.
According to another preferred embodiment, a system having an expander for expanding and feeding an expandable slit sheet material with reduced damage to the expandable slit sheet material is provided that includes: a) a feeder that feeds or allows feeding of the expandable slit sheet material downstream; b) at least two expansion rollers located downstream from the feeder which receive the expandable slit sheet material from the feeder, the at least two expansion rollers being adapted to rotate to move the expandable slit sheet material further downstream at a faster rate than a rate of the expandable slit sheet material proximate the feeder, such as to cause the expandable slit sheet material to expand due to the increased faster rate; c) the at least two expansion rollers including two expansion rollers arranged such as to be separated in a longitudinal feeding direction of the expandable slit sheet material, at least one of the two adjacent expansion rollers including a plurality of hooks distributed around a periphery thereof which are configured to engage slits of the expandable slit sheet material; d) the two adjacent expansion rollers being separated from one another in the longitudinal feeding direction of the expandable slit sheet material by a distance greater than a thickness of the expandable slit sheet material in a fully expanded state, such that the two adjacent expansion rollers do not concurrently press against opposite sides of the expanded slit sheet material at a same longitudinal position of the expanded slit sheet material so that the two adjacent expansion rollers avoid damaging the expanded slit sheet material.
According to some exemplary embodiments, the feeder includes a first feeding roll that is adapted to rotate at a reduced rate (in some other embodiments, the feeder can include a non-rotated bar around which the extendable paper passes in feeding downstream and/or another feeding mechanism that actively or passively directs or allows the expandable sheet to be fed downstream).
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that a portion of the path of the expanded slit sheet material passing around the two adjacent expansion rollers is S-shape, with the path curving in a first direction around a periphery of one of the two adjacent expansion rollers and then in a second direction that is away from the first direction around a periphery of the other of the two adjacent rollers.
According to some exemplary embodiments, the distance is greater than ½ inch.
According to some exemplary embodiments, the distance is greater than 4 inches.
According to some exemplary embodiments, the distance is greater than 6 inches.
According to some exemplary embodiments, the system is an envelope manufacturing system.
According to some exemplary embodiments, the system is configured to manufacture an envelope having the expanded slit sheet material in a peripheral wall of the envelope for protection of an item within the envelope.
According to some exemplary embodiments, the at least one of the two adjacent expansion rollers including a plurality of hooks distributed around a periphery thereof which are configured to engage slits of the expandable slit sheet material includes an upstream-most one of the two adjacent expansion rollers.
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material a most upstream one of the two adjacent expansion rollers around an arc of at least 40 degrees therearound.
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material contacting a most upstream one of the two adjacent expansion rollers around an arc of at least 60 degrees therearound.
According to some exemplary embodiments, the two adjacent expansion rollers are arranged such that the path of the expanded slit sheet material passing around each of the two adjacent expansion rollers includes the expanded slit sheet material a most upstream one of the two adjacent expansion rollers around an arc of at least 90 degrees therearound.
The above and/or other aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims.
The preferred embodiments of the present invention are shown, by way of example, in the accompanying drawings, in which:
While the present invention may be embodied in many different forms, the illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and that such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.
Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated otherwise.
In some of the preferred embodiments of the present invention, hooks of hook and loop fastening systems are employed. In the context of such preferred embodiments of the present invention, the term “hook” encompasses (i.e., includes) a hook portion of a hook and loop combination that encompasses the hook and loop system. In that regard, a hook is the portion that can grab the expanded slit sheet and the expanded sheet acts as the loop.
Hook-and-loop fasteners and hook-and-pile fasteners have been used with clothes and a wide variety of other items and applications. In some existing hook and loop fasteners, the fasteners include two thin plastic strips or sheets, one covered with tiny loops and the other with tiny flexible hooks. In use, when the two strips or sheets are pressed together, the flexible hooks engage with the tiny loops, adhering the two strips or sheets together. Then, the two strips or sheets can be separated by pulling apart the strips or sheets such as to disengage the hooks from the loops. Thus, hook-and-loop fasteners and hook-and-pile fasteners generally contain two components: typically, two lineal fabric strips which are attach together by hooking one strip to the opposing surfaces of the other strip. The first component featuring a multitude of tiny hooks distributed on a surface of, the second features smaller loops.
In some illustrative embodiments, hooks employed in some embodiments of the present invention can include features as described in any of the following patents and publications, the entire disclosures of which are all incorporated herein by reference:
For the purposes of the present invention, the term “S” shape means a double curve in the path of the expandable paper that forms a shape generally similar to the letter “S” or generally similar to a backwards letter “S” (e.g., 2). However, the terminology S shape does not suggest any particular degree of curvature or any particular similarity to a letter S. Notably, as long as at least a portion of the path of the expandable paper curves first in one direction and then in an opposite direction, it is within the scope of this terminology S shaped. The terms “S shape” and “S curve” and “S pattern” are employed herein as synonyms. In an S curve paper path, a line between the axis of a first hook roller to the axis of the second hook roller intersects with the path of the expandable paper in a region of the expandable paper between the first and second hook rollers at an acute angle. The region of the expandable paper between the first and second hook rollers is a region that extends from a first point where the expandable slit paper tangentially leaves the first hook roller to a second point where the expandable slit paper tangentially contacts the second hook roller. Furthermore, the terminology S shape or S curve, while meaning a double curve as discussed above, is not limited to and does not require just two curves; the system can include additional curves, as long as the double curve is included. For example, some embodiments can have three or more curves.
For the purposes of the present invention, the term “hook” encompasses any member that is capable of hooking, catching or grabbling slits within an expandable slit paper, and a “hook” encompasses, for example, a tine, prong and/or spike, that is arranged to extend from the hook roller and shaped to spear, hook, catch, and/or grab an edge of a slit. In the preferred embodiments, such tine, prong and/or spike, would include a narrow elongated base portion (e.g., a shaft portion) and a laterally extending distal portion (e.g., a curved tip, a bent tip, a barb, an enlarged head portion, etc.). In the preferred embodiments, the hooks of the hook rollers are configured to engage the slits of the expandable paper, and, in such an engaged state, to move the expanded or expanding slit paper by pulling the slit sheet paper as the hook roller rotates. In the preferred embodiments, such hooks, tines, prongs and/or spikes, having, e.g., barbed tips for engaging edges of expanding and expanded the expandable slit paper sheet to form, e.g., hexagonal cells that are formed in slit paper include flexible hooks, tines, prongs and/or spikes which are capable of flexibly engaging within the slits and flexibly disengaging with the slits in a similar manner to how common hook and loop fasteners have flexible hooks that are engageable and disengageable with corresponding loops.
As explained herein, in the preferred embodiments, systems and methods of the preferred embodiments of the present invention can be employed for expanding an expandable slit sheet similar to that shown in
In some preferred embodiments, expansion rollers (e.g., hook rollers) work in conjunction with feeding rollers (e.g., a pair of rubber type pinch rollers) that operate preferably at a slower speed (e.g., about a 67 percent slower speed) than the expansion rollers (e.g., hook rollers). This speed differential causes the slit sheet to expand. Although the speed differential of 67 percent is employed in some illustrative embodiments, it should be appreciated that the speed differential can vary based on the degree of expandability of the expandable slit sheet paper. Accordingly, other embodiments can have different differential is speeds based on circumstances. By way of example, in some embodiments the differential can include the pinch rollers operating, e.g., between about 25 to 100 percent slower than the speed of the hook rollers (i.e., expansion rollers). However, as long as the expansion rollers (e.g., hook rollers) operate at a higher rate than the feeding rollers (e.g., pinch rollers) leading thereto, such as to effect expansion of the expandable slit sheet material, the speed differential can be appropriate under the circumstances.
The expansion process is a self-feeding mechanism whereby the material exits the expansion rollers (e.g., hook rollers) expanded on a continuous basis. Among other things, the use of a larger distance between the expansion rollers (e.g., hook rollers) than the thickness of the slit sheet expanded eliminates crushing while expanding and feeding the slit material outward.
In some preferred embodiments of the present invention, a new technology is provided that creates a tension between the rollers by forcing the paper to travel around a first hook roller and then, a short distance away, around a second hook roller. In preferred embodiments, a sharp “S” shaped turn maintains enough tension on both sides of the expanded slit sheet so that the expanded slit sheet does not slip backward towards the feeding rollers (e.g., rubber pinch rollers) which would cause the sheet to revert to becoming partly or fully unstretched and thus unexpanded.
In some embodiments, the non-crushing expansion roller (e.g., hook roller) system can be used for a plurality of purposes. For example, a first advantageous use is with an automatic machine at a packing station similar to that found in the background art (see U.S. Pat. No. 5,688,578 incorporated herein by reference in its entirety). Another exemplary use is in the manufacture of envelopes, and, most desirably, envelopes as described in provisional applications Nos. 62/712,867 and 62/714,739, filed on Jul. 31, 2018 and Aug. 5, 2018, respectively, and incorporated herein by reference as if recited in full, as well as described in co-pending U.S. application Ser. No. 16/531,017 filed on Aug. 3, 2019, the entire disclosure of which is also incorporated herein by reference.
In the case of the use for wrapping at a packing station, if the expansion rollers (e.g., hook rollers) are too far apart as to not create a tight S turn that is sufficient enough to maintain tension, then the expanded slit sheet could fall back (i.e., slip) when the paper is not being used to wrap material. If the paper does fall back, then the loading hook loader 108, as shown in
In some exemplary embodiments, a thickness of the expanded sheet is about 3/16″; in these exemplary embodiments, a preferable distance between the rollers would be at or about 3/16″ to ¼″, or, in some other embodiments, up to about ½″. In some less preferred embodiments with an expanded sheet having a thickness of about 3/16″, the distance between the rollers can be greater, such as, e.g., up to about ⅔″, or, even up to about ¾″ or even more. Although some embodiments of expanded slit sheet has a thickness of about 3/16″ as noted above, it should be appreciated that other embodiments can have different thicknesses of the expanded slit sheet paper when in an expanded state. For example, in some examples, the thickness in the expanded state can be about 1/16″; or, in some examples, this thickness can be about 2/16″; or, in some examples, this thickness can be about 4/16″; or, in some examples, this thickness can be about 5/16″; or, in some examples, this thickness can be about 6/16″; or, in some examples, this thickness can be about 7/16″; or, in some embodiments, this thickness can be about 8/16″; or in some embodiments the thickness can be even greater. In such other embodiments, the distance between the rollers is preferably within a range proportional to the examples set forth above with respect to the 3/16″ thickness examples.
In some embodiments, the distance between the adjacent rollers is the same as or, alternatively, approximately the same as the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 20% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 40% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 60% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 80% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 100% greater than the thickness of the expanded slit sheet material (i.e., up to about twice as large). In some other embodiments, the distance between the adjacent rollers is up to about 120% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 140% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 160% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 180% greater than the thickness of the expanded slit sheet material. In some other embodiments, the distance between the adjacent rollers is up to about 200% greater than the thickness of the expanded slit sheet material (i.e., up to about three times as large). In some other embodiments, the distance between the adjacent rollers is even greater, such as, e.g., up to about 300% or more.
In the preferred embodiments, the shape of the S turn would be such that the expanded sheet leaving the first roll would be perpendicular or slightly less than perpendicular providing an acute angle towards the next roller. The purpose is two-fold. The more acute the angle, the more the paper has to involve the radius of the roller prior to exiting.
It should also be noted that for the purposes of the drawings the exact tolerances, such as dimensions and clearances, of the paper guides are not illustrated in the drawings. The guides, as shown in
In the case of a continuous pulling of the expanded sheet, as found when making envelopes, then the critical placement of the hooks is less critical and would be spaced further apart and perpendicular for the purposes of easier paper loading. The use of the paper guides may or may not be necessary or preferable if other equipment interferes with the easy access to the non-crushing hooks system. In the most preferable design, the tolerances could be made the same as what was just described for the equipment used at the packing station.
Nevertheless, the concept of maintaining friction between two hook rollers based on their proximity and the resultant changing paper directions that create the S turns is very advantageous and enables providing the best cushioning available from expanded slit sheet material, equivalent to the manual system created by the inventor described in U.S. patent application Ser. No. 15/820,514 incorporated herein by reference, as if recited in full. Manual pulling of the expanded sheet eliminates the need for pre-expansion and eliminates the hook rollers and, therefore, avoids any crushing, creating a non-crushed expanded slit material that maximizes the value of its cushioning properties.
Paper guides and an additional hook roller facilitate an easy loading method for guiding the paper through the pinch roller and through to the S curve hook automatically to the rollers. When the paper has been loaded properly and is stretching and feeding consistently, the third hook roller 108 of
In
Looking further to
With reference to
The contact region advantageously is greater than ¼ of the circumference (i.e., 90°), and preferably greater than ½ of the circumference (i.e., 180°), and, most preferably, up to about 250°, which produces contact of the paper with about 70% of the hook surface of the rollers.
Furthermore, contact of the slit sheet with the hooks of each roller is preferably advantageously in the range from 90° to less than 270°. More preferably, contact of the slit sheet with the hooks of each roller is in the range from 180° to 235° which produces contact of the paper in the range from about 50% to 65% of the hook surface of the rollers. As shown in in the embodiment of
In
For illustrative purposes,
As also depicted in
It should be appreciated that
Thus, while the preferred embodiments provide a structure that enables automated or machine controlled expansion of expandable slit sheet material, it should be appreciated that such automated or machine controlled expansion of expandable slit sheet material can employ a wide variety of drive mechanisms and mechanisms to control rotation and movement of rollers, etc., in accordance with the preferred embodiments of the invention.
Although some preferred embodiments employ two expansion rollers that form an S-curve as shown, e.g., in the embodiments of
For illustrative purposes,
In some of the more preferred embodiments, the expansion rollers preferably each include hooks distributed on their peripheries. For example, in the embodiments shown in
However, although the expansion rollers preferably each include hooks distributed on their peripheries, in some embodiments one or more of the expansion rollers can include hooks distributed around their peripheries (i.e., as long as at least one of the expansion rollers includes such hooks distributed on its periphery), while other(s) of the expansion rollers can omit such hooks. For example, in some illustrative embodiments, rather than employing such hooks, such other(s) of the expansion rollers can include a rubber, foam or other higher friction surface without employing such hooks.
However, in some of the more preferred embodiments, if any of the expansion rollers do not include hooks distributed on their peripheries, at least a first roller (i.e., a most upstream of the expansion rollers) would include such hooks. Notably, this can be particularly important in the context of a device in which the expanded sheet that is fed downstream from the expansion rollers is first cut, such as, e.g., with a die cutter. Among other things, this is helpful for ensuring that the expandable slit sheet material is expanded more evenly. In the event that such hooks are distributed on the second expansion roller downstream but not on the first expansion roller downstream, this could potentially lead to chaotic opening of the cells that can cause a rippling effect across the web of expanded slit sheet paper.
In embodiments in which a system or method of the present invention is employed for wrapping of a product (e.g., in which the expanded slit sheet material is fed downstream for wrapping of a product), in order to most appropriately expand the material preferably all of the expansion rollers include hooks distributed on their periphery. Among other things, in this context, it is important to avoid slippage of the expanded slit sheet material. In such embodiments, it is also helpful to include three expansion rollers (rather than two in many of the illustrated embodiments shown herein) to help further reduce potential for slippage. In addition, in this context, it is also helpful to minimize the distance between the expansion rollers to further minimize potential slippage. If there is slippage, then the slit sheet material slips backwards (i.e., upstream) away from the stage downstream of the expansion rollers (such as, e.g., a wrapping device or a packer {e.g., a human packer} that is situated downstream of the expansion rollers) and makes it difficult to wrap or pack the next item as, e.g., a packer reaches in for the material that has slipped backward.
On the other hand, in the case of an automated downstream system, such as, e.g., in the case of an automated envelope manufacturing system, the expanded slit sheet material leaving downstream from the expansion rollers can be handled in a manner that is not readily slipped. For example, in some embodiments, the expanded slit sheet material is fed downstream to a gluing device that continuously pulls the expanded material. Accordingly, in that context, there is a reduced risk of slippage. Accordingly, in the context of an automated downstream system, such as, e.g., in the context of an automated envelope manufacturing system, then some of the expansion rollers can omit hooks around their peripheries without significant risk of slippage issues described above.
In the context of manufacturing of an envelope, in some examples, a single expansion roller can include hooks distributed around the periphery in a manner to sufficiently apply a uniform stretch—i.e., because the expanded slit sheet paper is held by downstream equipment during the manufacturing of the envelope process. In some preferred embodiments, when manufacturing an envelope, the hook material on the expansion rollers helps maintain the width of the expanded slit material, which is helpful for downstream fabrication of the envelope in some embodiments. For example, in some embodiments, in a downstream step from the expansion rollers, the expanded slit sheet material is glued along the sides of the expanded slit sheet material, and the hooks help to ensure that the expanded slit sheet web is not varying in width an extent that could, thus, lead to incomplete gluing of the sides.
In some embodiments, the expandable slit sheet paper is initially in an unslit state. For example, the unslit paper can be fed initially to a first roller that is essentially a die cutter that cuts the slits into the paper. In some embodiments, the die cutter has foam wrapped around it, so that the slit paper is held firmly and evenly upon exiting the die cutter. After being fed from the die cutter, in the preferred embodiments, the first expansion roller is preferably wrapped or surrounded by a material having an distribution of hooks (e.g., which roller operates at a faster rate to stretch and expand the expandable slit sheet paper).
Accordingly, as discussed above, in many preferred embodiments of the invention, all of the expansion rollers (e.g., hook rollers), such as, e.g., all of the expansion rollers (e.g., hook rollers) shown in
In the illustrated embodiment, the paper sheet PS web is fed to a die cutting roller DCR that is configured to cut a slit pattern in the paper sheet PS, such that the paper sheet PS is formed into an expandable slit sheet ESS. Although not shown, in some illustrative embodiments, the die cutting roller can include another cooperative roller that together cut the paper sheet PS (such as, e.g., employing peripheral blades on one of the cooperative roller or the die cutting roller that cut slits as the paper sheet is conveyed past the die cutting roller. This structure can be similar to that of the background art for formation of slit patterns of expandable slit sheet material. In the preferred embodiment, as discussed above, the die cutting roller DCR rotates at a rate that conveys the paper sheet PS at a first reduced speed.
As shown in
As shown in
Notably, in the preferred embodiments, the degree of the arc of contact between the expandable slit sheet ESS and the hook roller HR is preferably an arc of at least 40 degrees. In some other embodiments, the arc of contact is at least 60 degrees. In some other embodiments, the arc of contact is at least 80 degrees. In some other embodiments, the arc of contact is at least 100 degrees. In some other embodiments, the arc of contact is at least 120 degrees. In some other embodiments, the arc of contact is at least 140 degrees. In some other embodiments, the arc of contact is at least 180 degrees, or even more in other embodiments (similar to that described above). However, in some preferred embodiments, the arc of contact is between about 60 to 120 degrees.
In the embodiment shown in
With reference to
While the invention has been described in terms of several preferred embodiments, it should be understood that there are many alterations, permutations, and equivalents that fall within the scope of this invention. It should also be noted that there are alternative ways of implementing both the process and apparatus of the present invention. For example, steps do not necessarily need to occur in the orders shown in the accompanying figures and may be rearranged as appropriate. It is therefore intended that the appended claim includes all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar references in the context of this disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as, preferred, preferably) provided herein, is intended merely to further illustrate the content of the disclosure and does not pose a limitation on the scope of the claims. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the present disclosure.
Multiple embodiments are described herein, including the best mode known to the inventors for practicing the claimed invention. Of these, variations of the disclosed embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing disclosure. The inventors expect skilled artisans to employ such variations as appropriate (e.g., altering or combining features or embodiments), and the inventors intend for the invention to be practiced otherwise than as specifically described herein.
Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
The use of individual numerical values is stated as approximations as though the values were preceded by the word “about”, “substantially”, or “approximately.” Similarly, the numerical values in the various ranges specified in this application, unless expressly indicated otherwise, are stated as approximations as though the minimum and maximum values within the stated ranges were both preceded by the word “about”, “substantially”, or “approximately.” In this manner, variations above and below the stated ranges can be used to achieve substantially the same results as values within the ranges. As used herein, the terms “about”, “substantially”, and “approximately” when referring to a numerical value shall have their plain and ordinary meanings to a person of ordinary skill in the art to which the disclosed subject matter is most closely related or the art relevant to the range or element at issue. The amount of broadening from the strict numerical boundary depends upon many factors. For example, some of the factors which may be considered include the criticality of the element and/or the effect a given amount of variation will have on the performance of the claimed subject matter, as well as other considerations known to those of skill in the art. As used herein, the use of differing amounts of significant digits for different numerical values is not meant to limit how the use of the words “about”, “substantially”, or “approximately” will serve to broaden a particular numerical value or range. Thus, as a general matter, “about”, “substantially”, or “approximately” broaden the numerical value. Also, the disclosure of ranges is intended as a continuous range including every value between the minimum and maximum values plus the broadening of the range afforded by the use of the term “about”, “substantially”, or “approximately”. Thus, recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. To the extent that determining a given amount of variation of some the factors such as the criticality of the slit patterns, paper width differential pre- and post-expansion, paper weights and type, as well as other considerations known to those of skill in the art to which the disclosed subject matter is most closely related or the art relevant to the range or element at issue will have on the performance of the claimed subject matter, is not considered to be within the ability of one of ordinary skill in the art, or is not explicitly stated in the claims, then the terms “about”, “substantially”, and “approximately” should be understood to mean the numerical value, plus or minus 15%.
It is to be understood that any ranges, ratios and ranges of ratios that can be formed by, or derived from, any of the data disclosed herein represent further embodiments of the present disclosure and are included as part of the disclosure as though they were explicitly set forth. This includes ranges that can be formed that do or do not include a finite upper and/or lower boundary. Accordingly, a person of ordinary skill in the art most closely related to a particular range, ratio or range of ratios will appreciate that such values are unambiguously derivable from the data presented herein.
This application is a continuation of U.S. application Ser. No. 16/749,875, filed on Jan. 22, 2020, which is non-provisional of U.S. Provisional Application No. 62/795,310 filed on Jan. 22, 2019, entitled Expansion System for Non-Crushing Slit Sheet, by David Paul Goodrich, the entire disclosures of which are incorporated herein by reference.
