Patent Description:
In a manufacturing process for a continuous web, it is often needed to splice the terminal end of the web from an expiring roll and the leading end of the web from a new roll. According to a known method, the expiring web and the new web are threaded between a pair of rollers which are brought together so as to bring a portion of the expiring web into contact with a portion of the new web and then splicing them together by overlaying a suitable adhesive between them. In the case of an overlap splice, this adhesive can be provided by a double-sided adhesive tape previously applied manually by an operator to the leading end of the new web.

<CIT> concerns the field of packaging apparatuses, and in particular that of high-speed machines and systems for packaging products such as tissues, serviettes or other similar paper products with printed plastic film (polypropylene, polyethylene, PVC etc.). A feeding unit from reels of sheet-like material comprises two unrolling shafts of respective reels of material, for feeding in turn said material towards means for cutting and welding the tail of material of a running out reel and the head of a fresh, loaded reel. Such means comprise suction, cutting and welding devices movable so as to approach and move away from each other to press the material over a welding plane.

Manufacturing processes can use a variety of web splicing equipment with varying degrees of automation. Unique product specifications and requirements, however, can present challenges in reliably splicing different webs. One of these challenges relates to web registration for webs having a repeating visual pattern that are used for decorative and/or functional purposes. Products produced on converting lines sometimes contain patterns and/or images that are precisely located on the product itself or its packaging. There is a productivity and waste reduction benefit to splice these input webs such that the pattern/image on the web from the expiring roll aligns precisely to the pattern/image on the web of the new input roll. Two webs aligned and spliced in this manner is known as a registered splice. To maximize throughput and reduce costs, there is a significant technical benefit to automatically creating a registered splice with minimal or no disruption to the web manufacturing process.

The subject-matter of the present invention is defined by the features of the independent claims.

In a first aspect, an apparatus for splicing a patterned web is provided. The apparatus comprises: first and second unwind spindles engaging a new roll of the patterned web and expiring roll of the patterned web, respectively; a first web indexing mechanism capable of linearly translating the patterned web from the new roll along its travel direction; a first clamp surface that extends across the patterned web from the new roll; a second clamp surface that extends across the patterned web from the expiring roll; a cutting mechanism for severing the patterned web from the expiring roll; and a second web indexing mechanism capable of linearly translating the patterned web along its travel direction from the expiring roll. The first and second web indexing mechanisms are independently operable to align registration features of the patterned web on the new roll and the expiring roll with each other, whereby the first and second clamp surfaces can be brought together to create a registered splice of the patterned web between the new and expiring rolls. The apparatus of the present invention comprises additional features as defined in independent claim <NUM>.

In a second aspect, a process for splicing a patterned web is provided, comprising: using a first web indexing mechanism to position a first segment of the patterned web from a new roll between opposing first and second clamp surfaces at a first registered location; using a second web indexing mechanism to position a second segment of the patterned web from an expiring roll between the opposing first and second clamp surfaces at a second registered location; bringing the first and second clamp surfaces together to create a registered splice; and severing the patterned web from the expiring roll upstream from the registered splice using a cutting mechanism. The process of the present invention comprises the additional features as set out in independent claim <NUM>.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.

Provided is an apparatus that can provide a registered splice of two sections of a continuous web. Advantageously, this process can be carried out in an automatic or semiautomatic manner. Useful applications for the apparatus and process include the manufacturing or converting of any web-based products that can have a patterned outer surface. Such webs may be used in adhesive-backed tapes, patterned films, reflective sheeting, commercial laminates, and graphic wraps. Depending on the application, the pattern present on the web can be decorative, functional, or both.

It is desirable for equipment used to splice in new rolls of material while maintaining the pattern to minimize waste generated as a result of a splice. It is common for splices made using conventional methods to generate some number of rejected parts. If registration isn't maintained, however, the equipment could generate large numbers of rejected parts, depending on the sizes of the parts at issue. A second and, potentially greater impact is that if registration is not maintained in some processes, significant down time may result in the manufacturing process as a result of jamming induced in die modules located downstream from the splicer, or causing webs to tear out of the machine.

An exemplary apparatus for splicing a patterned web is shown in <FIG> and herein referred to by the numeral <NUM>. The apparatus <NUM> includes various subassemblies, including a splicing module <NUM>, web indexing mechanism <NUM>, and web accumulator <NUM>. Also illustrated in <FIG>, a continuous patterned web <NUM> travels through the aforementioned subassemblies in the same order as listed above.

The splicing module <NUM>, web indexing mechanism <NUM>, and web accumulator <NUM> cooperatively provide a configuration enabling the web <NUM> to be continuously dispensed from the apparatus <NUM> at a constant line speed before, during, and after splicing. Advantageously, this configuration eliminates the need for interruptions during a manufacturing or converting process and helps to maximize throughput, reducing waste and reducing production costs.

Within the apparatus, the splicing module <NUM> includes a first spindle from which the web <NUM> is unwound and spliced. The web indexing mechanism <NUM>, located downstream from the splicing module <NUM>, engages and pulls the web <NUM> from the splicing module <NUM> at a pre-determined rate. This rate is not particularly limited, and can be controlled by a computer such as a programmable logic controller (PLC) operatively coupled to the web indexing mechanism <NUM>.

The web indexing mechanism <NUM> can operate using any known way of engaging and moving a continuous web with minimal speed variations. In a preferred embodiment, the web indexing mechanism <NUM> is comprised of a pull nip. The pull nip is comprised of a pair of nip rollers that are pressed together to grip and draw the web <NUM> from the splicing module in a controlled manner. It is common for at least one of the nip rollers to be made from a low durometer material (e.g., rubber) so that the rollers maintain good contact with the web <NUM> and avoid slippage. Motors are generally engaged to the PLC to drive the nip rollers and advance the web <NUM> upon demand.

As further illustrated in <FIG>, the web indexing mechanism <NUM> also includes an upper registration sensor <NUM>. The upper registration sensor <NUM> is capable of detecting one or more registration features on the web <NUM>. This capability can be used, in turn, to assist the web indexing mechanism <NUM> in adjusting the position of the web <NUM> to a precise pre-determined position when creating a registered splice of the web <NUM>. Details of the upper registration sensor <NUM> and its operation will be described later.

The web accumulator <NUM> is located downstream from the web and allows for core changes and web splicing to occur while the manufacturing or converting process continues at a constant line speed. The web accumulators can have any known configuration. Festoon-style web accumulators, like the one shown in <FIG>, are most common, but others such as horizontal coil accumulators could also be possible.

<FIG> shows features of the splicing module <NUM> in more detail. As shown, the splicing module <NUM> includes a first unwind spindle <NUM> and a second unwind spindle <NUM>. A new roll <NUM> of web <NUM>' is mounted on the first unwind spindle <NUM> and an expiring roll <NUM> of web <NUM> is mounted on the second unwind spindle <NUM>. The web <NUM>' from the new roll <NUM>, which is to be spliced to the web <NUM>, is guided around lower idler roll <NUM>, upper idler roll <NUM>, and has a terminal segment secured to a first clamp surface <NUM>.

Here, for the sake of clarity, it is noted that the term "patterned web" can be used to refer either to patterned web from the new roll, patterned web from the expiring roll, or both. Where applicable, the numerals <NUM> and <NUM>' distinguish between these portions of the patterned web, which eventually become one and the same after they are spliced together.

The web <NUM> from the expiring roll <NUM> is guided around lower idler roll <NUM>, past upper idler roll <NUM>, past a second clamp surface <NUM>, additional idler rolls, and eventually feeds into the web indexing mechanism <NUM> (located above the splicing module <NUM> and not depicted in <FIG>). In this embodiment, the web <NUM> does not contact the second clamp surface <NUM>. Sliding contact between these bodies is permissible, however, so long as such contact does not interfere with conveyance of the web <NUM> through the splicing module <NUM>.

As further shown in <FIG>, the splicing module <NUM> is further assisted by a second web indexing mechanism. Optionally, this second indexing mechanism is provided by a holding nip <NUM> that includes an arm <NUM> extending upwardly from a pivot joint <NUM> and terminating in a pressure roll <NUM>. Upon demand, a PLC or other computer can cause the arm to rotate either clockwise or counterclockwise about the pivot joint <NUM> to nip the web <NUM>', <NUM> between the pressure roll <NUM> and the respective upper idler roll <NUM>, <NUM>.

The splicing module <NUM> further includes a pair of cutting mechanisms <NUM>, <NUM>' located downstream from the holding nip <NUM> and upstream from the first and second clamp surfaces <NUM>, <NUM>. The cutting mechanism <NUM>, <NUM>' is configured to sever respective web <NUM>, <NUM>' on demand and can be electronically controlled by a computer. In a simple embodiment, the cutting mechanism <NUM>, <NUM>' is comprised of a physical blade capable of slicing the web <NUM>, <NUM>' perpendicular to the direction of web travel (and perpendicular to the plane of the page in <FIG>). Although not depicted here, it is possible to use a single cutting mechanism capable of selectively cutting either web <NUM> or web <NUM>'. Cutting mechanisms based on other principles are also possible for certain applications, including those using lasers or high-pressure water jets.

Advantageously, the clamp surfaces <NUM>, <NUM>, holding nip <NUM>, and cutting mechanism <NUM>, <NUM>' are components of a registration carriage <NUM>. The registration carriage <NUM> is operatively coupled to a motor that allows these components, while having fixed positions relative to each other, to be collectively translated along the direction of web travel. Here, in the figures, the direction of translation is upwards or downwards. Translation of the registration carriage <NUM> occurs relative to the static components of the splicing module <NUM>, particularly the first and second unwind spindles <NUM>, <NUM> and lower idler rolls <NUM>, <NUM>. As shown in <FIG>, the registration carriage can move along a direction that makes a slight angle relative to the web travel direction; these directions need not be precisely parallel with each other.

Adjacent to the webs <NUM>, <NUM>' are lower registration sensors <NUM>, <NUM>, which are located downstream from the first and second unwind spindles <NUM>, <NUM> and upstream from the lower idler rolls <NUM>, <NUM>. This particular configuration is exemplary only, however, and it is to be understood that the lower registration sensors <NUM>, <NUM> could achieve their purpose when anchored to any of a number of locations upstream from the registration carriage <NUM>. Moreover, the upper registration sensor <NUM> can be located any position downstream from the registration carriage <NUM>. Both the upper registration sensor <NUM> and lower registration sensors <NUM>, <NUM> thus move independently from the registration carriage <NUM>.

<FIG> shows the splicing module <NUM> in the process of a splicing operation. The steps of this operation shall now be described below with reference to both <FIG> and <FIG>.

At the outset, the web <NUM>' is dispensed from the new roll <NUM> on the first unwind spindle <NUM> and threaded up to the first clamp surface <NUM>. The terminal segment of the web <NUM>' can be attached to the first clamp surface <NUM> using a single-sided adhesive tape <NUM> (also shown in <FIG>) whose adhesive-coated side faces towards the opposing second clamp surface <NUM>. The adhesive tape <NUM>, as shown in <FIG>, extends slightly beyond the terminal segment of the web <NUM>' such that a portion of the adhesive is directly adhered to the web <NUM>' while a remainder of the adhesive is left exposed. The adhesive tape <NUM> itself can be secured to the first clamp surface <NUM> pneumatically (e.g., by suction), using a temporary adhesive, clip, or any other reversible fastening mechanism. In an exemplary embodiment, this step is carried out manually by an operator, but this step could be automated if so desired.

With the terminal segment of the web <NUM>' affixed to the first clamp surface <NUM>, the holding nip <NUM> can then be shifted leftward, clamping the pressure roll <NUM> web to the upper idler roll <NUM>. This provides sufficient anchorage to assist the registration carriage <NUM> in pulling the terminal segment of the web <NUM>' upwards along with it, generally in the direction of web travel. The PLC will then instruct a servo motor coupled to the registration carriage <NUM> to translate it upwards in a linear motion, applying tension to the web <NUM>' while pulling additional material from the new roll <NUM>. In a preferred embodiment, the servo motor and lower registration sensor <NUM> communicate with each other through the PLC.

While the web <NUM>' is being pulled, the PLC can use the lower registration sensor <NUM> to locate a pre-determined registration feature on the web <NUM>' from the new roll <NUM>. The registration feature can be any distinctive marking on the web <NUM>' that provides information about the location of the web. Typically, the registration feature is a visual indicia such as a distinctive image, line, edge, pattern, or color. Registration features, in some cases, could be based on a topological feature such as a ridge, groove, or bump.

For detection of visual registration features, a given registration sensor can have any degree of sophistication. In some embodiments, the sensor is an optical sensor. The optical sensor can use any combination of components for lighting, lenses, vision processing, image sensing, and/or communications. The detection of a feature may be achieved using sensors based on a charged couple device (CCD) or a complementary metal oxide semiconductor (CMOS) that converts light into electrical signals. These signals can be processed into a digital image with sufficient detail to provide reliable registration to a particular location on the patterned web <NUM>' and be recognized by processing software. The precision of the location information obtained from the registration sensor can vary depending on the sensor used. In some embodiments, a repeatability of <NUM> milliseconds, <NUM> milliseconds, or even <NUM> milliseconds could be achieved, based on a line speed of <NUM> centimeters/second. At this line speed, a repeatability of <NUM> milliseconds corresponds to a spatial resolution of approximately <NUM> micrometers.

Once this registration feature is detected, the translation of the registration carriage <NUM> will immediately stop, fixing the web <NUM>' in a registered position and orientation relative to the frame of reference of the apparatus <NUM>.

When the expiring roll <NUM> is almost depleted, a signal is sent to the PLC indicating that a splicing operation should begin. The PLC then actuates a motor operatively coupled to the web indexing mechanism <NUM>, where both are in communication with an upper registration sensor <NUM> through the PLC. Assisted by the motor, web indexing mechanism <NUM> engages and pulls the web <NUM> from the expiring roll <NUM> through the splicing module <NUM> until it detects a pre-determined registration feature on the web <NUM> from the expiring roll <NUM>. Notably, the registration feature used for positioning the web <NUM> can be the same as, or different from, the registration feature detected by the lower registration sensor <NUM> in the earlier step above. Once this registration feature is detected, the PLC commands the web indexing mechanism <NUM> to stop the web <NUM>.

At this moment, the respective registration features of webs <NUM>, <NUM>' will be precisely aligned with each other between clamp surfaces <NUM>, <NUM>. Therefore, as described in this exemplary process, the holding nip <NUM>, as mounted the registration carriage <NUM>, and the web indexing mechanism <NUM> independently operate to align registration features of the patterned web <NUM>, <NUM>' on the new roll <NUM> and expiring roll <NUM> with each other.

During the time that the web <NUM> is stopped within the splicing module <NUM>, the web accumulator <NUM> allows the overall apparatus <NUM> to continue dispensing the web <NUM> at a constant and pre-determined rate. At this point two segments of web <NUM> from the new roll and expiring roll will be aligned with each other along the first and second clamp surfaces <NUM>, <NUM>. The PLC then causes the first and second clamp surfaces <NUM>, <NUM> to be brought together, creating the registered splice between webs <NUM>, <NUM>'. <FIG> shows the configuration of the splicing module <NUM> at this exact moment.

The cutting mechanism <NUM> is then activated to sever the web <NUM> from the expiring roll <NUM>. Once severed, the holding nip <NUM> and first and second clamp surfaces <NUM>, <NUM> will disengage and the new roll <NUM> will begin dispensing the patterned web <NUM>'.

From this moment, the new roll <NUM> of web <NUM>' will eventually become a new expiring roll and the previous expiring roll <NUM> can be discarded and replaced with a new roll. Advantageously, the symmetry of the splicing module <NUM> enables further splicing operations to occur in a continuous fashion, which the new and expiring rolls swapping positions after each splicing operation. In the subsequent splicing operation, designations of rolls <NUM>, <NUM> (and associated idler rolls <NUM>, <NUM>) are reversed. Further, the lower registration sensor <NUM> and cutting mechanism <NUM>' would be used in the subsequent splicing operation instead of the lower registration sensor <NUM> and cutting mechanism <NUM>.

It is preferable that at least some of the aforementioned sequence of steps be carried out in an automated manner. To this end, various steps may be directed with the assistance of a PLC or other computer. For example, a computer can be used to guide one or more of the operations described, including translating the registration carriage <NUM>, stopping the dispensing of the expiring roll <NUM>, the bringing of the first and second clamp surfaces <NUM>, <NUM> together, and the cutting of the web <NUM> downstream from the registered splice. In a preferred embodiment of the splicing process, a computer is used to carry out all of these steps in the order provided above.

A second embodiment is shown by apparatus <NUM> in <FIG>. The apparatus <NUM> is configured to provide a butt-splice of the patterned web, rather than an overlap splice. Like apparatus <NUM>, apparatus <NUM> includes various subassemblies, including the unwind spindles <NUM>, <NUM>, splicing module <NUM>, web indexing mechanism <NUM>, and web accumulator <NUM>. A left registration sensor <NUM> and right registration sensor <NUM> are positioned to locate registration features on a continuous patterned web, which is omitted from <FIG> and <FIG>. The continuous patterned web travels through the aforementioned subassemblies in the same order as listed above. Unlike in previously described apparatus <NUM>, there is no registration carriage-each of the aforementioned components are generally fixed in a single frame of reference.

<FIG> shows particular details of the splicing module <NUM>, including holding clamp surfaces <NUM>, <NUM>, first and second tail pull nips <NUM>, <NUM> and first and second cut drums <NUM>, <NUM>. The first and second cut drums <NUM>, <NUM> each has a respective cutting mechanism <NUM>', <NUM> on one side and a respective clamp surface <NUM>, <NUM> on the other side. Generally, operation of the apparatus <NUM> is similar in many respects to that of apparatus <NUM>, except the apparatus <NUM> does not use a web indexing mechanism based on a holding nip on a movable carriage. Instead, the first and second web indexing mechanisms are provided by the web indexing mechanism <NUM> and either of tail pull nips <NUM>, <NUM>, respectively, depending on whether the new roll is on the first or second unwind spindle <NUM>, <NUM>.

In an exemplary process, a new roll of patterned web is mounted on the first unwind spindle <NUM> and threaded up through the splicing module <NUM>. Tension is then applied by the tail pull nip <NUM>, which draws the web through the space between the first and second cut drums <NUM>, <NUM> and immediately stops when a pre-determined registration feature is detected by the left registration sensor <NUM>.

Once the expiring roll from the second unwind spindle <NUM> is near expiration, the machine will then use the web indexing mechanism <NUM> interfacing with registration sensor <NUM> to detect a pre-determined registration feature and lock the expiring portion of the web to a proper registered position. Reaching this position stops the web within the splicing module <NUM>, while the web accumulator <NUM> allows upstream converting or manufacturing equipment to continue running.

At this point, the portions of the web from the new and expiring rolls will be mutually aligned, allowing the holding clamp surfaces <NUM>, <NUM> to come together. The terminal ends of the web are then created by severing the new and expiring sections of the web and then immediately splicing them to each other with a strip of adhesive-backed tape. Both of these operations can be executed in quick succession using the first and second cut drums <NUM>, <NUM>, which instantly rotate <NUM>° to toggle between (<NUM>) a cutting orientation in which the cutting mechanism <NUM>, <NUM>' cuts the web and (<NUM>) a taping orientation where one of the opposing first and second clamp surfaces <NUM>, <NUM> applies a pre-mounted adhesive-backed tape across the cut. After separating the clamp surfaces <NUM>, <NUM>, the web accumulator <NUM> can be paused and the upstream manufacturing or converting process resumed. The expired roll can then be replaced with a new roll.

Claim 1:
An apparatus (<NUM>, <NUM>) for splicing a patterned web (<NUM>) comprising:
first and second unwind spindles engaging a new roll (<NUM>) of the patterned web (<NUM>) and expiring roll (<NUM>) of the patterned web (<NUM>), respectively;
a first web indexing mechanism capable of linearly translating the patterned web (<NUM>) from the new roll (<NUM>) along its travel direction;
a first clamp surface (<NUM>, <NUM>) that extends across the patterned web (<NUM>) from the new roll (<NUM>);
a second clamp surface (<NUM>, <NUM>) that extends across the patterned web (<NUM>) from the expiring roll (<NUM>);
a cutting mechanism (<NUM>, <NUM>) for severing the patterned web (<NUM>) from the expiring roll (<NUM>); and
a second web indexing mechanism capable of linearly translating the patterned web (<NUM>) along its travel direction from the expiring roll (<NUM>),
wherein the first and second web indexing mechanisms are independently operable to align registration features of the patterned web (<NUM>) on the new roll (<NUM>) and the expiring roll (<NUM>) with each other, whereby the first and second clamp surfaces (<NUM>, <NUM>) can be brought together to create a registered splice of the patterned web (<NUM>) between the new and expiring rolls,
the apparatus (<NUM>, <NUM>) being characterized in that it further comprises a registration carriage (<NUM>) capable of being translated along a travel direction of the patterned web (<NUM>), and in that the first and second clamp surfaces (<NUM>, <NUM>), the first web indexing mechanism, and the cutting mechanism (<NUM>, <NUM>) are coupled to the registration carriage (<NUM>) and the first and second unwind spindles and the second web indexing mechanism are not coupled to the registration carriage (<NUM>).