This disclosure relates to rewinding machines that wind a web material around central cores to form logs of wound web material. Specifically, the disclosure is directed to an improved apparatus and method for winding and for controlling the logs during the introduction, winding, and discharge phases. In particular, a core end engagement assembly is provided for a rewinding machine. The core end engagement assembly is configured to engage an end of the core and transmit rotational movement to the core during winding of the web material about the core. The assembly may include a drive housing with a hollow interior. A chuck may project from a first end of the drive housing and may be configured to engage the end of the core. A first actuator may reciprocate the drive housing along a central axis of the core between an engagement and disengagement position of the chuck relative to the core. A second actuator may be mounted on the drive housing. The second actuator may be configured and adapted to move the chuck between hold and release positions. A flexible drive shaft operatively connects with and rotationally drives the chuck.
A rewinder is used to convert large parent rolls of web into smaller sized rolls of bathroom tissue, kitchen towel, hardwound towel, industrial products, nonwovens products, and the like. A rewinder line consists of one or more unwind stations, modules for finishing—such as embossing, printing, perforating—and a rewind station at the end for winding. Typically, the rewind station produces logs having a diameter of between 90 mm and 180 mm for bath tissue and kitchen towel and between 150 mm to 350 mm diameter for hardwound towel and industrial products. The width of the logs is usually 1.5 m to 5.4 m, depending on the parent roll width. Typically the logs are subsequently cut transversely to obtain small rolls having a width of between 90 mm and 115 mm for bath tissue and between 200 mm to 300 mm for kitchen towel and hardwound towel. In some cases the web from the parent roll is slit into ribbons and wound with the finished roll width at the rewind station, without the need for subsequent transverse cutting.
Two types of rewinding systems are commonly used: center winders and surface winders. The defining characteristic of center winders is that the web is wound on a core that is supported and rotationally driven by a mandrel within the core. The defining characteristic of surface winders is that the web is wound into a log that is supported and rotationally driven by machine elements at the log periphery. Most surface winders have tubular cores in the log. However, some operate with mandrels; and some use neither, instead producing solid rolls.
It has been known in the industry that center winders are effective at winding low firmness, high bulk logs, but have certain limitations. They cannot produce firm products at high speeds effectively because the only control is incoming web tension. Higher web tension will produce a firmer log, but higher web tension correlates with more frequent web blowouts due to bursting of perforations or tearing from defects along the edges of the web. Also, center winders cannot run high speeds at wide web widths due to the slender mandrel inside the log producing excessive log vibration at various natural frequency modes. Another limitation is the challenge in running high cycle rates due to the time in the cycle required to decelerate the log gradually, and the time in the cycle to remove the finished log from the mandrel.
It has been known in the industry that surface winders are effective at winding high firmness, low bulk logs, but have certain limitations. It is a challenge to produce low firmness, large diameter products at high speeds effectively because of the occurrence of excessive log vibration. The vibration can be severe enough to cause winding defects, such as wrinkles and eccentric cores; sheet defects, such as variation in the embossed pattern, damaged perforations, and tattered tail in the last web wrap; or operational problems, such as breakage of the web and failure to discharge a finished log.
Nonetheless, it is generally acknowledged in the industry that surface winders have more advantages overall. They have higher cycle rate potential because no time is required in the cycle for withdrawing full-length mandrels from the cores. They have greater width potential because the elements that support and drive the log can be as large in diameter as necessary, or utilize intermediate supports, to accommodate large widths, even for high converting speeds. They also have lower cost potential because they do not have complex mandrels inside the cores. They can wind high and moderate firmness products well. They can wind low firmness products too, though at lower speed to avoid onset of excessive log vibration.
In some cases the elements of the center winder and surface winder have been combined to partially offset the drawbacks of each. Rider rolls may be added to center winders, for instance, to assist in producing lower bulk, firmer logs. Chucks or plugs that engage and rotationally drive the ends of the cores may be added to surface winders, for instance, to assist in producing higher bulk, less firm logs. These are referred to as center-surface winders or rewinders, and sometimes as hybrid winders or rewinders.
Trends in the market for bathroom tissue and kitchen towel have been for larger diameter rolls that feel softer, due to lower wound firmness, and are produced with less material. The amount of material may be reduced by decreasing the product length, thus requiring higher cycle rates of the rewinder. It may also be reduced by decreasing the density of the substrate, such as by using structured web or specialized embossing, which tends to render the thickness of the web more fragile. A major challenge is that larger diameter logs composed of less material and wound with less firmness are more prone to excessive vibration at high, and sometimes even moderate, web speeds. Excessive vibration can cause winding defects, sheet defects, and operational problems, as described above. Having to reduce the winding speed to avoid excessive vibration reduces the production capacity of the converting line, which is not economical.
Therefore the market desires a rewinding system that can wind low firmness products at higher speeds without excessive log vibration. The need is most acute for a winding system that can wind low firmness products of large diameter at higher speeds without excessive log vibration.
The market further desires a rewinding system that is tolerant of variations in properties of the web material, so that the operator need not be extraordinarily vigilant, nor require specialized skills, to make compensatory adjustments during the course of production. This may be a system that is inherently tolerant, also known as robust. It may be a system that automatically makes its own compensatory adjustments. It may be a combination of both.
The disclosure that follows describes an improved apparatus and method for winding web material around central cores to form logs of wound web material, and for controlling the logs during the introduction, winding, and discharge phases. At least one belt is used in conjunction with a winding drum, which feeds the web, to form a winding nest. Between the drum and belt is a space through which the winding cores are inserted and through which the web material is fed. The belt is a continuous flexible member arranged as an endless loop, operably mounted so it can be moved with a velocity tangent to its surface.
In one aspect of the disclosure, the belt is made to move with surface velocity in a direction generally opposite that of the inserted core and feeding web. This surface velocity of the belt, acting with the generally opposite surface velocity of the winding drum, causes the log to turn in rotation to wind the web material.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum to control the advancement of a log through the space between the winding drum and the belt into the winding nest.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum to control the winding of a log in the winding nest.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum to control the discharge of a log from the winding nest.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum and the distance between the belt and the winding drum is varied cyclically to control the advancement of a log through the space between the winding drum and the belt into the winding nest.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum and the distance between the belt and the winding drum is varied cyclically to control the winding of a log in the winding nest.
In another aspect of the disclosure, the surface velocity of the belt is varied cyclically relative to the velocity of the winding drum and the distance between the belt and the winding drum is varied cyclically to control the discharge of a log from the winding nest.
In another aspect of the disclosure, the winding nest is provided with a rider roll, which is rotatably mounted, and is movable relative to the winding drum and the belt to allow an increase in diameter of each log in the winding nest.
In another aspect of the disclosure, the winding nest is provided with at least one rotationally driven core chuck that engages the end of the core inside the winding log to apply a torque to the core. In a further aspect of the disclosure, the winding nest is provided with two rotationally driven core chucks, one at each end of the core, that engage the ends of the core inside the winding log to apply a torque to the core.
In another aspect of the disclosure, the winding nest is provided with two rider rolls, which are each rotatably mounted, and are movable relative to the winding drum, the belt, and each other, to allow an increase in diameter of each log in the winding nest.
In another aspect of the disclosure, a stationary rolling surface is provided upstream from the belt, on the same side of the space between the winding drum and the belt as the belt, wherein the inserted core is driven in rotation by the winding drum along the stationary rolling surface and then into a space between the winding drum and the belt.
In another aspect of the disclosure, the belt is substantially under the winding log in the winding nest.
In another aspect of the disclosure, the core chuck or core chucks insert and engage the core ends after the log is in contact with the belt and the winding drum, and they disengage and withdraw before discharge of the log from the winding nest.
In another aspect of the disclosure, the winding log remains substantially in contact with the winding drum during a preponderance of the winding cycle, until it is nearly complete, when it separates from the winding drum at the start of log discharge from the winding nest.
In another aspect of the disclosure, the winding log remains substantially in contact with the belt during a preponderance of the winding cycle, from when it first contacts the belt, until it moves away from the belt during log discharge from the winding nest.
In another aspect of the disclosure, the winding log remains substantially in contact with a rider roll during a preponderance of the winding, from when it first contacts the rider roll, until it is nearly complete, when it separates from the rider roll during log discharge from the winding nest.
In another aspect of the disclosure, the winding log remains substantially in contact with the winding drum, the belt, and a rider roll during a preponderance of the winding.
In another aspect of the disclosure, the winding log remains substantially in contact with the winding drum, the belt, a rider roll, and a further rider roll during a preponderance of the winding.
In another aspect of the disclosure, the winding log is substantially in contact with the winding drum, the belt, and a rider roll during a portion of the winding cycle; then it is substantially in contact with the belt, the rider roll, and a further rider roll during a later portion of the wind cycle, the winding log having been moved out of contact with the winding drum.
Shown approximately vertical in the drawings is a pinch plate 56 that may be used to perform the web cut-off similar to the system shown in U.S. Pat. No. 6,056,229, the disclosure of which is incorporated by reference. While the drawings show the web W approaching the winding drum 50 generally vertically, the approach angle of the web to the winding drum 50 may be rightward or leftward of the generally vertical shown in the drawings. The pinch plate may be provided in a corresponding manner relative to the angle of approach of the web to the winding drum 50. Shown to the left and lower left of the winding drum are fingers 58 and a curved rolling surface 60 that may be used to guide a core 62 during web transfer and then guide the rolling log 64 to the winding region, similar to the system in U.S. Pat. No. 6,056,229. Other web severing mechanisms and/or web transferring mechanisms may be provided including systems disclosed in U.S. Pat. Nos. 5,538,199, 5,839,680, 5,979,818, 7,614,328, 5,150,848, 6,422,501, 6,945,491, 7,175,126, 7,175,127, 8,181,897, 9,586,779, EP 3148906, and other systems for severing the web on the winding drum with a movable blade or pinching pad and/or transferring the web vis-à-vis a longitudinal line or circumferential rings of glue or moisture, electro-static means, or a web tucking system. Although the description that follows describes a single belt, the description is not intended to be limiting in any sense and several parallel belts may be provided. Additionally, the term belt is not intended to be limiting, and may be viewed as a continuous flexible member arranged in an endless loop capable of being imparted with a velocity tangent to its surface, regardless of whatever material, materials, or construction techniques afford the function and properties described herein. Additionally, the term core or winding core is used to describe any center or inner structure about which the web material may be wound, including a tubular or solid mandrel, spindle, axle, shaft, cardboard core, nucleus of wound material, cores that are removed in operations subsequent to winding for making coreless products, for instance as shown in U.S. Pat. No. 9,284,147, etc. Further, the term “web” is intended to cover material in wide webs, narrow webs, single webs, and a plurality of webs (ribbons), whether slit or cut after unwinding, or derived from multiple unwinds.
When the core 62 is introduced by the inserter (not shown) for web transfer, it is guided into contact with the winding drum 50 by the transfer fingers 58, which are on the opposite side of the core inserting channel as the winding drum. When the core 62 contacts the winding drum 50, it very abruptly undergoes a step increase in its rotational velocity and is driven in rotation along the curved rolling surface 60 by the winding drum 50 toward the belt 52. The curved rolling surface 60 and winding drum 50 define the core inserting channel. The shape of the curved rolling surface 60 is generally concave with respect to the winding drum, and is spaced away from the winding drum at a distance slightly less than the diameter of the winding log, more preferably slightly less than the diameter of the core in the log, if the core is radially compliant and can radially flex as it rolls through the channel. Radial compression of the log, and more preferably also radial compression of the core, ensures positive rotation of the log as it is driven through the core inserting channel by the winding drum. As shown in
After the winding log 64 has been brought into contact with the belt 52 it must be advanced further through the space between the winding drum 50 and the belt 52 toward the winding nest N. This may be referred to as log introduction or log progression. It is understood that this is a critical phase in the winding cycle for control because the log is advancing very rapidly and increasing in diameter very rapidly. If properly controlled, the winding log 64 will decelerate both rotationally and translationally as it advances toward the winding nest N and remain in contact with both the winding drum and the belt during this transition. To bring the log 64 forward into the winding nest N, the belt 52 has a lower surface speed than the surface speed of the winding drum 50. The speed of the belt 52 may be varied through the product cycle according to a profile such that the log progresses into the winding nest N in a controlled fashion. Preferably the speed profile of the belt 52 is calculated as a function of the delivered web, log diameter, log position, or any combination thereof. The speed profile of the belt is calculated to advance the log 64 in a controlled fashion wherein contact of the log 64 is maintained with the winding drum 50 and the belt 52. During this introduction phase of the winding cycle the gap distance between the winding drum 50 and the belt 52 may be kept at a relatively constant dimension. In this case, the log advancement is controlled by the speed profile of the belt 52. Because the log first contacts the belt 52 slightly before the narrowest point in the space S between the winding drum 50 and the belt 52, and because the log is growing in diameter very rapidly at this time, the log may compress or deform radially as it passes forward through the narrowest point. This technique may be used to cause tight winding of the initial web wraps near the core through the elevated nip pressures. The level of tightness of winding at the start can be lowered by bringing the log into contact with the belt closer to and even at the narrowest point in the space S between the winding drum 50 and the belt 52. Depending upon the application, and especially applications at relatively higher speeds, where the incoming log has greater momentum, the belt surface speed may be operated faster so that the log does not skid through the nip, lose contact with the winding drum, and cease rotating. Thus, as the winding log is brought closer to the narrowest point in the space S between the winding drum 50 and the belt 52 for its initial contact, belt speed may be increased.
Thus, belt speed and belt position relative to the winding drum may be changed as necessary based upon the application speed, size of the product, and desired firmness of the resultant log. Having the belt at a relatively fixed position relative to the winding drum may be more effective for tighter winding, which may be desired for certain firm and high firmness products.
When winding less firm and low firmness products tighter winding at the start is not desirable. To accommodate operational flexibility in this regard, a second degree of freedom may be added to the belt 52 so that the distance between the belt 52 and winding drum 50 may be varied through the product cycle according to a profile that allows the log to progress into the winding nest N in a controlled fashion without being radially compressed or deformed by passing through a narrow nip point. Preferably, the position profile of the belt 52 is calculated as a function of the delivered web, log diameter, log position, or any combination thereof. The position profile of the belt may be calculated to advance the log 64 in a controlled fashion wherein contact of the log 64 is maintained with the winding drum 50 and the belt 52. In this case, the log can be brought into contact with the belt farther from the narrowest point in the space S between the winding drum 50 and the belt 52 with greater control and without a tendency toward tight winding. In this case, the log advancement is controlled by the speed profile of the belt 52 and the position profile of the belt 52, which in combination afford greater control and winding quality for less firm and low firmness products.
As the winding log 64 continues to advance into the winding nest N and increase in diameter the speed of the belt 52 may continue to be increased. The winding log 64 has its greatest translational advancement velocity when it first contacts the belt 52, because the space between the winding drum 50 and the belt 52 diverges only slightly, does not diverge, or even slightly converges. As the winding log 64 advances farther and farther into the winding nest N, the surfaces of the winding drum 50 and the belt 52 diverge ever more greatly, and the log increases in diameter at an ever slower rate due to its increasing circumference. Therefore the surface speed of the belt 52 is relatively slower at the beginning of each cycle and is increased during the winding cycle to correctly control the log. Then, near the end of the winding cycle, the speed of the belt is slowed to cause the nearly finished log or finished log to discharge from the winding nest N. The slowing of the belt 52 causes the completed log 64 to roll rightward in the drawings, out of the winding nest N, on to a discharge surface 68 for further processing. This rightward travel preferably commences slightly before the web is severed for transfer to the next core, but it may commence at the same time the web is severed, or after the web is severed. A further purpose of slowing the belt 52 near the end of the winding cycle is to have the belt sufficiently decelerated to the correct velocity for controlling the next log 64 when it arrives at the belt 52 for introduction and advancement into the winding nest N. The start of the deceleration may be timed to cause a correct discharge of the finished or nearly finished log. The magnitude of the deceleration may be chosen to cause a correct introduction of the next log. The magnitude of the deceleration may be chosen to cause a correct discharge of the finished or nearly finished log and to cause a correct introduction of the next log.
A control of the rewinder may establish a speed differential between the winding drum and the belt, which in turn controls the log progression through the nip between the winding drum and the belt. The surface speed of the belt may be at its lowest speed just before the arrival of the core/log so that the belt is increasing in speed when it is contacted by the core/log. The surface speed of the belt may be increased through the winding cycle as the growth of the log diameter and the geometry of the winding nest require a slower forward progression of the log. The surface speed of the belt may be relatively rapidly decreased near the end of the winding cycle, which in turn causes the log to start to advance more rapidly again for discharge. The control may store in memory a speed profile correlating belt speed over time, or belt speed versus wind cycle fraction, for the wind cycle. The belt speed profile may be executed as a position controlled motion. A speed profile may be executed as a position controlled motion by integrating a velocity profile. The belt speed profile may be preset (i.e., calculated and stored in a memory of the control of the rewinder) based on requested product parameters and then may be modified during the wind cycle, or between wind cycles, as needed. The belt speed profile may be preset for at least the intermediate phase of the winding cycle during which a preponderance of the log winding takes place. The belt speed profile may also be preset for the log introduction and/or log discharge phases. The belt speed profile may be calculated to account for log progression within the winding nest, increase of the log diameter during the winding, movement of the belt position, or any combination thereof. A calculated speed profile may be used that is based on the physics of the process to promote uniform winding, maximum diameter, and reduced vibration.
The rider roll 54 may be positioned in the winding nest N with a positioning mechanism 70 (
The discharge surface 68 may be provided downstream from the end of the belt 52. The discharge surface 68 may include a table that has a starting position just beyond the point where the belt starts to curve around the rotatable pulley 66. If multiple parallel belts are used, the table may include fingers that interdigitate with the spacings between parallel belts. The fingers may extend beyond the curved portions of the belts, so that the log 64 transitions more gradually from the surfaces of the belts to the fingers of the discharge table. The discharge table fingers may have coordinated motion with the belt positioning mechanism, so a constant relationship is maintained between the fingers and belts. The discharge table fingers may be positionable independent of the belts, for instance, to recede beneath the belts at a position farther upstream in the winding nest for smaller diameter products and farther downstream in the winding nest for larger diameter products. The fingers may be positioned in order to set a desired distance over which the logs roll on the belts as they discharge. A discharge gate, or other device known in the art, may be provided downstream of the winding nest to capture a finished wound log, and/or control the timing of the exit of the finished wound log from the rewinder.
Without being limited to any theory, it is believed that a winding nest comprising a winding drum and belt, for instance as shown in
The substantially flat, even possibly slightly convex, deformation of the log at its nip with the belt 52 may provide other advantages and may be enhanced by varying the characteristics or adjustments of the belts. The material on the surface of the belt may be compliant, and thus conform under the load of the log, increasing its contact area, and reducing the contact pressure and deformation on the log. The belt itself may be stretchable or elastic, and may extend under the load of the log, wrapping the log slightly, increasing its contact area, and thereby reducing the contact pressure and deformation on the log. The tension setting in the belt may also be varied to influence the contact pressure and deformation on the log. Additionally, the position of the belt under the winding log, where it bears a preponderance of the weight load of the log, may be advantageous over other configurations of winding nests or other possible positions of a winding belt with respect to the log.
In a surface rewinder winding nest, the log is supported at its periphery. In the case of a winding nest with just winding drums, the log weight load is supported by the drums, typically primarily a lower winding drum. In a winding nest with upper and lower winding drums, little can be done to cause a reduction of the pressure in the nip at the lower winding drum, because the weight of the log causes the pressure. However, given the shape of the belt 52 for reducing nip pressure, as described above, the same log weight may be supported with less nip pressure, as compared to a lower winding drum. Therefore, positioning the belt under the log, where it may support a preponderance of the weight of the log, may be especially beneficial for larger diameter, low firmness logs, which add weight load as they increase in size, and thus encounter rising nip forces through the wind cycle.
A belt could be utilized on any side of the winding log, but under the log is the most effective location partly because the weight load of the log is unavoidable. When winding low firmness logs in a 3-drum surface rewinder efforts can be made to reduce the nip pressures at the upper winding drum and the rider roll (though not as effectively as with a belt system, as is described in the next paragraphs of the disclosure), but little can be done about the weight of the log on the lower drum, and the nip there would typically have the greatest pressure, and its nip pressure would increase as the diameter of the log increases. So under the log is the most favorable position for the belt to alleviate a nip pressure. The arrangement may also be advantageous with processing of structured and/or textured webs (e.g., NTT, QRT, etc.), or specialized embossing in the web, during the wind cycle, because the lower contact pressure in the nip of the belt configuration compared to a configuration with a winding drum may tend to reduce thinning of the web material from crushing or compressing its structure or texture or its embossing. A reduced magnitude of radial deformation of the log in its nip with the belt, compared to a nip with a winding drum, may also induce less strain in the web wraps as they pass through the nip, which may help preserve the thickness of structured web and prevent elongation of the structured web. This in turn may reduce the potential for the structured web to reach a strain threshold beyond which a significant portion of the thickness of the structured web does not return to its nominal thickness when the tension load is removed or reduced.
As described above, without being limited to any theory, it is believed that reducing the nip pressure on a winding log may reduce interlayer slip within the log, and thereby facilitate winding low firmness and low firmness large diameter logs at higher speeds without excessive vibration, or with less vibration. Thus, it is believed that a benefit may be derived by reducing the pressure at all nips with the winding log, including at the winding drum and any rider rolls. A further advantage in using a belt beneath the winding log, and having it nearly or substantially horizontal, such as inclined from horizontal by less than 15° (more preferably by less than 11°, and more preferably by less than 7°) is that in this configuration it may allow for lower nip pressures between the log and the winding drum and the rider roll(s). It can be seen that the winding drum 50 bears substantially none of the weight of the log, so the surface speed of the belt 52 can be used to adjust the nip pressure independent of the log weight. Increasing the belt speed may increase the contact pressure at the nip between the log and the winding drum. Decreasing the belt speed may reduce, minimize, or even eliminate, the contact pressure at the nip between the log and the winding drum. It can be seen that if the inclination of the belt is zero degrees the rider roll also bears substantially none of the weight of the log, and if the inclination is a small angle, the rider roll may bear only a small fraction of the weight of the log. Decreasing the belt speed may increase the contact pressure at the nip between the log and the rider roll. Increasing the belt speed may reduce, minimize, or even eliminate, the contact pressure at the nip between the log and the rider roll. Optimizing the speed and position of the belt and the position of the rider roll may result in reduced, minimized, or even eliminated contact pressures at the nips between the winding drum and log and the rider roll(s) and log.
The belt 52 may be provided with a belt positioning mechanism (
Without being limited to any theory, it is believed that a winding nest comprising a winding drum and belt, for instance as shown in
The belt 52 may be of unitary construction, or consist of at least two portions: (i) a log contact side that engages the log, and (ii) a pulley contact side that engages a pulley that drives the belt. The log contact side of the belt may have a covering layer. The log contact side of the belt is preferably wear resistant and has a high traction and/or high grip characteristic. The log contact side of the belt may comprise a rubber or elastomer type of material with high grip characteristics. The log contact side of the belt may comprise a rough surface with high traction characteristics. The log contact side of the belt may be changed or modified to have more or less grip or traction. A covering layer of the belt may be softer or harder, thicker or thinner, more or less compliant, depending upon the application, to provide desired characteristics for the interaction of the belt and the winding log. Surface textures may be imposed or deployed on the log contact side of the belt by casting, imprinting, machining, laser engraving, implanting, etc. Protrusions or embossments may be utilized on the log contact side of the belt. A high traction and/or grip characteristic on the log contact side of the belt is preferable to afford control of the winding log at its nip with the belt in the introduction, winding, and discharge phases even with minimal or minimized or low contact pressure at the nip. The pulley contact side of the belt may have a high traction and/or high grip characteristic, to reduce or minimize or eliminate slipping of the belt on the drive pulley during its acceleration and deceleration phases of the cycle. The pulley contact side of the belt may have an array of teeth which engage grooves in the pulleys to reduce or minimize or eliminate slipping of the belt on the pulley during its acceleration and deceleration phases of the cycle. The belt may have internal cords, as is known in the art, to increase its resistance to changing in length, so it remains substantially at a constant length during operation, including during its acceleration and deceleration phases of the winding cycle.
The tension in the belt 52 may be adjusted higher or lower depending upon the application to provide desired winding dynamics and interaction of the belt and the winding log. In one embodiment, tension in the belt 52 may be modified during the winding cycle as part of a winding profile, or based on sensors or other feedback measurements, in order to increase or reduce nip pressure, increase or reduce web elongation, reduce the log vibration, or alter other system characteristics. The tension may be changed in the belt 52 by moving one of the two pulleys 66 shown relative to the other, or by using a movable third pulley or movable sliding shoe (not shown) that acts against a span of the belt (e.g., the lower span) to alter the tension in the belt.
As mentioned earlier, rather than a single belt, a plurality of parallel spaced apart belts may be provided. For instance, each belt in the plurality of belts may be about 100 mm wide or up to about 500 mm wide or wider with a spacing or gap of about 25 mm between the belts. The rolling surface 60 from the infeed fingers 58 to the belts may be a contiguous surface or may comprise discrete fingers with spacing between the fingers. The fingers 58 may terminate short of the belt surface, or may project past the belt surface and interdigitate with the gaps of the parallel and spaced apart belts. Each of the belts in the plurality of belts may be independently adjustable to accommodate any variation between the belts. A tensioner, movable third pulley, or sliding shoe may be used in connection with each belt to provide an adjustment to ensure proper tension. The plurality of belts may be driven with one pulley or each belt may have a dedicated pulley.
As shown in
The core end engagement assembly 80 may be provided with a core chuck 82 to engage with one end of the core 62. A second core end engagement assembly axially opposite of the core 62 may also be provided. The second core end engagement assembly may also include a second chuck 82 to engage with the axially opposite end of the core 62. The chuck 82 may engage an end face of the core or inner diameter surface of the core or both. The core 62 may be rotationally driven by the chuck 82 of one or both of the core end engagement assemblies 80. The chuck 82 preferably engages the core 62 after the web has been transferred to the core. The chuck preferably engages the core 62 after the log has transitioned from the rolling surface 60 onto the belt 52 and therefore has relatively reduced translational velocity, compared to when rolling along the rolling surface 60. The chuck 82 may engage the core 62 after the log has passed through the narrowest point in the space S between the winding drum 50 and belt 52. The chuck 82 may engage the core before the log contacts the rider roll 54, when the log contacts the rider roll, or after the log is in contact with the rider roll. The chuck may engage the core when the log is in contact with the winding drum 50, belt 52, and a rider roll 54.
Each chuck 82 may be positioned in the winding nest N with a positioning mechanism 84. The chuck positioning mechanism 84 may allow for compound motion, arcuate motion, linear reciprocating motion or any combination thereof. Preferably, the chuck positioning mechanism 84 may operate with compound motion so it can match the center of the winding log, as the log increases in diameter, and the log center traces a nonlinear path. The chuck 82 may disengage before log discharge, and may disengage before the web is severed for the next transfer. The chucks 82 may reciprocate parallel to the core central axis for engagement to and disengagement from the core 62. The core end engagement assembly 80 may include a pneumatic, hydraulic, electronic or mechanical actuator 86 that allows the chucks 82 to reciprocate substantially in alignment with the core central axis for insertion into and withdrawal from the hollow ends of the core 62. The core end engagement assembly 80 may also have a pneumatic, hydraulic, electronic or mechanical actuator 88 that enables the chuck 82 to expand radially outward to engage the inner diameter surface of the core 62. For instance, as shown in
Prior to engaging the core 62, the chucks 82 may rotate to a speed matching the rotational speed of the core. A motor (not shown) coupled to a flexible drive shaft 96 may rotationally drive the chuck 82. The flexible drive shaft 96 may be coupled to the control rod 90 adjacent the actuator 88 at an axial end of the drive housing 94. The chucks 82 may rotate freely at the speed of the rotating log. Accordingly, the chucks may be idling chucks. The chucks 82 may also, or in the alternative, tend to impart a slight braking action against the log during at least part of the wind cycle. The braking action may be provided via a mechanical or magnetic clutch-type mechanism and/or via the motor.
After engaging the core 62, the chucks 82 may move axially away from each other, thereby developing an axial tension force in the core. Applying an axial tension force to the core may reduce, minimize, or delay vibration of a winding log, particularly if winding a lower firmness log and/or operating at a higher winding speed. After engaging a tubular winding core, the inner diameter surface of the core may be pneumatically pressurized through one or both of the chucks 82. The internal pneumatic pressure may be used to develop an axial tension force in the core. The core chucks may be used to control the winding of the log by opposing vibration, instability, telescoping, or any other unplanned or erratic movements during the winding cycle. The core chucks may be used to control interlayer slip within the log. The core chucks may be used to oppose interlayer slip. Without being limited to any theory, it is believed that opposing forward-phasing interlayer slip can be advantageous when winding web material into loosely wound rolls and/or low firmness rolls. It is believed that the core chucks may oppose forward-phasing interlayer slip by applying torque to the core in the direction opposite to the direction of rotation of the log. The core chucks may be used to promote interlayer slip. Without being limited to any theory, it is believed that promoting forward-phasing interlayer slip can be advantageous when winding web material into tightly wound rolls and/or high firmness rolls. It is believed that the core chucks may promote forward-phasing interlayer slip by applying torque to the core in the same direction as the direction of rotation of the log.
Each core chuck 82 is preferably driven in rotation by the motor (not shown) which has position and/or velocity feedback. A control of the rewinder may establish a speed profile for the core chuck 82. This speed profile may be relative to the winding drum speed, web feeding speed, and/or speed of the winding belt. The rotational speed of the chucks 82 may be relatively faster early in the wind cycle, when the log diameter is relatively smaller, and relatively slower later in the wind cycle, when the log diameter is relatively larger. The rotational speed of the chucks may be decreased through the winding cycle as the growth of the log diameter requires a slower rotation of the log center. The control may store in memory a speed profile correlating chuck speed over time, or chuck speed versus wind cycle fraction, for the wind cycle. The chuck speed profile may be executed as a position controlled motion. A speed profile may be executed as a position controlled motion by integrating a velocity profile. The chuck speed profile may be preset (i.e., calculated and stored in a memory of the control of the rewinder) based on requested product parameters and then may be modified during the wind cycle, or between wind cycles, as needed. The chuck speed profile may be preset for at least the intermediate phase of the wind cycle during which a preponderance of the log winding takes place. The chuck speed profile may also be preset for the return phase, wherein the chucks travel from their position at the end of winding a finished log to their position for engagement to the core of a subsequent log. During this return motion phase the chucks may increase in speed from a slower speed near the end of the cycle to a faster speed nearer the beginning of the cycle. The chuck speed profile during the winding phase may be calculated to account for log progression within the winding nest, increase of the log diameter during the winding, movement of the belt position, or any combination thereof. Calculated speed profiles that are based on the physics of the process can promote uniform winding, maximum diameter, and reduced vibration by eliminating the erratic slipping that typically occurs with approximated profiles that are created manually by operators or technicians, or with motion equations not tied to the physics of the process. The chuck speed profile may substantially match the rotational speed that theory suggests the winding core should have for the case of zero interlayer slip. The chucks may be caused to rotate faster for at least part of the cycle, causing a log to wind tighter. The chucks may be caused to rotate slower for at least part of the cycle, causing a log to wind looser. Offsetting, scaling, stretching, and/or other manipulations of this profile may be used to produce a speed profile wherein the chucks rotate faster or slower for at least part of the cycle.
Each core chuck positioning mechanism 84 may position the core end engagement assembly 80 in the winding nest N by a motor, or motors, which have position feedback. A control of the rewinder may establish a position profile for the core chuck. This position profile may be relative to the winding drum, winding belt, and/or rider roll(s). The control may store in memory a position profile correlating chuck position over time, or chuck position versus wind cycle fraction, for the wind cycle. The chuck position profile may be executed as a position controlled motion. The chuck position profile may be preset (i.e., calculated and stored in a memory of the control of the rewinder) based on requested product parameters and then may be modified during the wind cycle, or between wind cycles, as needed. The chuck position profile may be preset for at least the intermediate phase of the wind cycle during which a preponderance of the log winding takes place. The chuck position profile may also be preset for the return phase, wherein the chucks travel from their position at the end of winding a finished log to their position for engagement to the core of a subsequent log. The chuck position profile during the winding phase may be calculated to account for log progression within the winding nest, increase of the log diameter during the winding, movement of the belt position, or any combination thereof. The chuck position profile may substantially match the positions that theory suggests the winding core should have for the case of a circular log. Offsetting, scaling, stretching, and/or other manipulations of this profile may be used to produce a chuck position profile that takes into account deformation of the log by the winding elements, such as at the belt due to the weight of the log and/or due to pressure from the rider roll(s); and/or to affect the nip pressures of the log against the winding elements; or to produce any desired chuck position profile that differs from the set profile associated with the application.
Though speeds, motions, and positions of the winding elements are disclosed as preferably being calculated based on the machine geometry and physics of the winding process, this does not preclude manual or automated adjustments based on observation and/or feedback signals. For example, the core chuck speed may be adjusted based on a measurement of the core or log rotational speed. For example, the core chuck position may be adjusted based on a measurement of the core or log position. Any winding parameters and any speed, motion, and position profiles including the belt speed, belt position, rider roll speed, rider roll position, core chuck speed, core chuck position, and the web tension may be adjusted, refined, shifted, offset, stretched, or manipulated by an operator based on visual observation, product measurements, substrate measurements, or process measurements, or by the rewinder control system, based on sensor feedback or operator input. The observations, measurements, feedback, and data may include, and are not limited to, caliper of the incoming web material, machine direction tensile modulus of the incoming web material, z-direction modulus of the incoming web material, tension and changes in tension of the incoming web material, the diameter and/or firmness of wound logs, vibration of logs during winding, caliper of web measured in finished logs, comparison of measured properties in the web before winding and after winding, and comparison of a measured web caliper value to a calculated web caliper value for a roll. The calculated average caliper for a wound roll product may be obtained with the following equation, where the area of the cross-section of a roll is divided by the length of the web material wound into the roll.
In this equation c is the average caliper for a wound product, D is the finished diameter at the periphery of the roll, d is the diameter at the start of the web windings, which is typically the outside diameter of a winding core, and L is the machine direction length of the web that is wound into the roll.
The rider roll 54A closer to the winding drum 50 may engage incoming log 64 first. As the log 64 increases in diameter during the winding cycle, the rider roll 54A may travel toward the top of the winding log 64, making space for the rider roll 54B to engage the log 64 at the side of the log (per the drawings). For very small diameter logs, the system may be configured to use only one of the rider rolls, where there may not be space available to have both rider rolls 54A,54B engaged during a majority of the winding cycle. As shown in
Very Small—Only one rider roll is used, so the rider roll 54A or 54B controls the log winding and the log discharge in conjunction with the belt.
Small—The rider roll 54A controls the log discharge in conjunction with the belt and the rider roll 54B moves away from the log, so it does not block the exit path of the log.
Medium—The rider roll 54B orbits higher on the log 64 while still remaining in contact. Then the rider roll 54A initiates log discharge in conjunction with the belt. As shown in
Large—During winding of a large diameter log the rider roll 54A may be moved to an upstream side of the winding log 64 and no longer be above the log so that the rider roll does not assist with the log discharge. The rider roll 54B may orbit to a preferred discharge position and control the log discharge in conjunction with the belt. An example of a large log is shown in
Alternatively, for certain log diameters it may be preferable to move the rider roll 54A away from the winding log 64 to make space for the rider roll 54B to orbit higher to a more preferred position for log discharge (see
In the winding nest configuration as shown in
By way of example, the motions of the belt 52 and the rider rolls 54A,54B may be controlled to cause a gap between the winding drum 50 and the log 64 having a target dimension of 2 mm. A feedback loop associated with the control system may be enabled to sense whether a gap was created at this interface and measure its size. Though a gap may briefly form between the log 64, and the winding drum 50, the log may wind less tightly due to the reduced or eliminated pressure at its interface with the winding drum, and thus have relatively increased diameter and thereby rapidly or immediately fill this gap and resume contact with the winding drum. The feedback loop would sense the gap has closed. The control system may then, optionally, modify the motion profiles again to another target gap dimension or larger target gap dimension, possibly resulting in an even larger diameter log. This is advantageous when trying to maximize wound log diameter. The feedback of log diameter may be used to control the gap. For example, motions may be controlled to maintain the condition of no gap, intermittent gap, or an approximate size of a gap, when the desired log diameter is achieved. Motions may also be controlled to create a gap, create an intermittent gap, or increase the size of a gap, when the log diameter is too small. Motions may be controlled to eliminate a gap, eliminate an intermittent gap, or reduce the size of a gap, when the desired log diameter is too large. Motions may be controlled to eliminate a gap, eliminate an intermittent gap, or reduce the size of a gap, based on the level of the log vibration. Depending upon the amount of gap, one or both rider rolls may be controlled to have greater or less surface speed or positioned to provide greater or reduced pressure on the log, and/or the belt may be controlled to have greater or less surface speed. Even with a no-gap condition during stable log winding, there may be minimal nip pressure between the winding drum and the log so the winding drum for the most part delivers the web and only slightly drives rotation of the log. The gap may also close at least intermittently with log vibration. In this condition, the close proximity of the winding drum 50 to the log 64 serves to offer a fourth region of contact for log containment. The gap feedback may be used to adjust upstream processes such as embossing or calendaring, or web speed.
The beginning part of the winding cycle may be like the beginning of the winding cycle for the winding nest configurations of
Another alternate embodiment is a winding nest comprising a winding drum 50 and a belt 52 as shown and described in connection with
Disposed between the lower draw rolls 112 and the rewinder apparatus 120 is a web severing and core insertion apparatus 122. U.S. Pat. No. 6,422,501 discloses a core feeding, gluing, and insertion apparatus, which may be incorporated herein. Each core 62 may have a longitudinal line of transfer glue applied as it enters the rewinder apparatus 120. The core 62 may enter on guides (not shown) which bring it onto the lifting fingers at their lower shown position. These lifting fingers may rise to their upper shown position to load a core to the core inserter, which may receive and hold the core with vacuum. The lifting fingers may descend to their intermediate shown position, which allows a space beneath for a subsequent core to arrive and a space above for the core on the inserter to pass by. When the core inserter rotates clockwise to its insertion and web pinching positions, the lifting fingers may also rotate clockwise to move from above the core in the guides to beneath the core in the guides, which is a way to facilitate operation at high core loading and cycle rates.
U.S. Pat. No. 6,056,229 and U.S. Pat. No. 6,422,501 disclose a web severing and transfer apparatus which may be incorporated herein. A stationary pinch plate 56 may be provided on the same side of the web as the winding drum, in close proximity to the web. As the perforation which is to be severed to complete a winding cycle, and start the next winding cycle, approaches the winding drum, the core inserter rotates clockwise so the pinch pads disposed on it may approach the stationary pinch plate and the winding core disposed on it may approach the infeed fingers 58. The core inserter motion may be timed and phased to pinch the web against the stationary plate when the perforation is just downstream of the core, so in very rapid succession an abrupt tension rise severs the perforation and the core is pressed against the web between it and the winding drum and starts to rotate. As the core rotates the longitudinal strip of transfer glue may cause the leading edge of the web to adhere to the core and thus start winding of the log 64.
The log may continue along the transfer fingers 58 and rolling surface 60 to the winding nest N as previously described. The transfer fingers 58 and rolling surface 60 are shown supported on a beam 124. This beam 124 may be movable with respect to the winding drum 50 to adjust and optimize the distance from the drum to the fingers 58 and rolling surface 60. This movement may be used to adjust the distance based on the core diameter and/or core stiffness. The movement may be accomplished by supporting the beam on linear slides (not shown). The transfer fingers 58 may have a pivot mount with their inclination adjustable with a four-bar linkage. Their inclination may be adjusted to optimize the guiding of the core to its contact with the winding drum for the web transfer. Alternatively the transfer fingers 58 and/or rolling surface 60 may be exchanged for different shape parts to accommodate different core diameters, different core diameter ranges, and/or optimization of the distance to the winding drum 50.
Making reference to
Also, making reference to
Referring to
The coupler of this four-bar linkage may connect at the axis of the upstream pulley 66A. A crank arm and 4-bar linkage may be disposed at each end of the belt system and at least one intermediate support. The crank arms on the pivot are controlled by a motor with position feedback to execute the motion profile of the belt position for the log introduction and winding.
Making reference to
The rotational drive for the core chuck may comprise timing belts operating on pulleys which are mounted adjacent to and coaxial with the linkage joints. The timing belt drive may extend in sequence back to a motor with its axis of rotation mounted coincident to the lower pivot or the upper pivot, or near one of these pivots. However, it is desirable that the rotational drive train for the core end engagement assembly 80 have a relatively low level of inertia. It can be appreciated that the core chucks must rotate at very high speed at the beginning of the winding cycle and when they engage the core. Speeds of 5,000-8,000 rev/min and greater may be contemplated. For example, the rotational speed of a log with 38 mm diameter and 800 m/min surface speed is approximately 6,700 rev/min. If the diameter of the log is smaller and/or its surface speed is greater, then its rotational speed is proportionately greater. The core chuck may be operated at greater rotational speed than the log before it engages the core in the log so that it may have matched velocity and matched rate of change in velocity (acceleration), and conceivably also matched rate of change in acceleration, so as to cause minimal disruption to the log and core when it engages the core, and to minimize wear of the core chuck that may occur due to relative velocity between the core chuck and the core. The rotational speed of a log with 130 mm diameter and 800 m/min surface speed is approximately 1,960 rev/min. The rotational speed of a log with 200 mm diameter and 800 m/min surface speed is approximately 1,270 rpm. It can be appreciated that the inertia of the system should preferably be kept low so the torque required to execute such speed increases in the brief time after the chucks disengage from the core of a finished log and before they engage the core of a subsequent log is not excessive. The time for execution of these speed changes depends on the properties of the product being wound and the settings and speed of the rewinding machine. For winding products at diameters of or about the ranges described earlier in this document at typical and high operating speeds, the speed changes are preferably executed in less than 2 seconds, more preferably in less than 1 second, more preferably in less than 500 ms, more preferably in less than 250 ms. In the alternative to a series of drive belts and pulleys for driving the core chucks, the core chucks may have a drive train comprising the flexible drive shaft 96, as shown in
During operation, the frame arm of the core chuck positioning system 84 may be moved to align the chuck body with the end of the core 62. The first linear actuator 86 may retract to slide the drive housing 94 axially to insert the chuck body into the core end. When the chuck is inside the core the second linear actuator 88 may extend to axially move control rod 90 to engage the core (leftward in the drawings). The support shaft 92 is axially restrained so the annular elastic pieces are compressed axially and expand radially to engage the inside surface of the core.
The flexible drive shaft 96 may undergo changes in its curvature to accommodate the axial and spatial movements of the assembly as the core chucks are inserted into cores, as the core chucks track with the centers of winding logs, as the core chucks are withdrawn from the cores, and as the core chucks travel to align with the center of a subsequent log. Changes to the curvature of the flexible drive shaft may accommodate the axial movement of the control rod 90 when the assembly is shifted axially to insert or remove the chuck from a core. The flexible drive shaft may also accommodate the axial movement of the control rod 90 when second linear actuator 88 shifts axially to expand or contract the chuck, and movement of the control rod 90 through space by the core chuck positioning motors. Thus the flexible drive shaft may accommodate three translational degrees of freedom in addition to the rotational degree of freedom utilized to drive the chuck 82. It can be appreciated that the mass of the system should preferably be kept low so the torque required to execute movement from the position where the chucks disengage from the core of a finished log to where they engage the core of a subsequent log is not excessive. The time for execution of this movement depends on the properties of the product being wound and the settings and speed of the rewinding machine. For winding products at diameters of or about the ranges described earlier in this document at typical and high operating speeds, the movement is preferably executed in less than 2 seconds, more preferably in less than 1 second, more preferably in less than 500 ms, more preferably in less than 250 ms. A flexible drive shaft is especially beneficial to driving the rotation of the core chucks as they move through space due to its relatively very low mass and its ability to flex rapidly during the rapid movements of the core chucks along their multiple degrees of freedom. The flexible drive shaft is especially beneficial in that it accommodates the axial movement of the chucks when they insert and withdraw from the core ends, so that a spline connection, which is prone to rapid wear, is not required in the drive train. The flexible drive shafts have further merits with respect to driving the core chucks in that they are simple, simple to install, take little space, and are less prone to obstruct the view of the winding nest from the side of the machine than alternatives.
An advantage of the core chucks shown in
The embodiments were chosen and described in order to best explain the principles of the disclosure and their practical application to thereby enable others skilled in the art to best utilize said principles in various embodiments and with various modifications as are suited to the particular use contemplated. As various other modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
PCT/US2018/062462 | Nov 2018 | US | national |
This application claims the benefit of PCT application serial no. PCT/US2018/062462, filed Nov. 26, 2018, the disclosure of which is incorporated by reference herein. This application is also a continuation in part of U.S. application Ser. No. 16/201,034 filed Nov. 27, 2018, the disclosure of which is incorporated by reference herein.
Number | Date | Country | |
---|---|---|---|
Parent | 16201034 | Nov 2018 | US |
Child | 16416515 | US |