Interliner method and apparatus
10322899 ยท 2019-06-18
Assignee
Inventors
Cpc classification
B65H23/08
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
An improved method and apparatus for the interleaf winding of materials, especially adhesive, sticky, or tacky materials, which method involves maintaining a tension in the liner material at the point where it is mated with the material being wound.
Claims
1. A method of slitting a continuous prepreg sheet stock material and winding the resulting plurality of slit tape tows said method comprising 1) passing the prepreg sheet stock material through a slitter thereby slitting the prepreg material into a plurality of prepreg slit tape tows, 2) directing each tow of slit tape to a winding station, and 3) winding each slit tape tow with a liner material in an interleaf winding process whereby the continuous tow of a stock material is mated with a continuous tow of the liner material maintained at a constant tension at a mating point, before or concurrent with the winding of the mated materials on a spool, spindle, bobbin, reel or core element, the interleaf winding process employing an apparatus positioned intermediate a supply of the liner material and the mating point and comprising a) a tensioning device or means comprising (i) at least one stationary element, (ii) at least one non-stationary element, said at least one stationary element and said at least one non-stationary element defining a path for the liner material through the tensioning device or means and to the mating point, (iii) a dancer element or reciprocating armature device having a fixed end relative to the stationary element and a reciprocating end which comprises or upon which is seated the non-stationary element such that the non-stationary element is capable of moving in a reciprocating fashion along a path that, at one extreme, corresponds to the longest path for the liner through the tensioning device or means to the mating point and, at a second extreme, corresponds to the shortest path for the liner through the tensioning device or means to the mating point, and (iv) a biasing means acting, directly or indirectly, upon the dancer element or reciprocating armature which biasing means biases the non-stationary element towards the first extreme position corresponding to the longest liner supply path, b) a detector or sensor element or means for detecting at least one of 1) movement of the dancer element or reciprocating armature and, hence, movement of the non-stationary element along the aforementioned path, 2) changes in the tension of the liner material and/or 3) differences in the rate at which the liner material is being fed or drawn from the liner supply and the rate at which it is being taken up in the winding process, and c) a response element or means for, directly or indirectly, effecting a change or adjustment, at least on a temporary basis, in the rate at which the liner material is fed or drawn from the liner supply to the tensioning device or means, said apparatus adapted and aligned to maintain a constant tension in the liner material at the point where the liner material and the stock material being wound are mated.
2. The method of claim 1 wherein the detector or sensor element or means detects (1) movement of the dancer element or reciprocating armature and, hence, movement of the non-stationary element along the aforementioned path.
3. The method of claim 1 wherein the detector or sensor element or means detects (2) changes in the tension of the liner material between the liner supply and tensioning device or means.
4. The method of claim 1 wherein the detector or sensor element or means detects (3) differences in the rate at which the liner material is being fed or drawn from the liner supply and the rate at which it is being taken up in the winding process.
5. The method of claim 1 wherein each of the detector or sensor elements or means and each of the response element or means are independently a mechanical device or element or an electronic device or system.
6. The method of claim 5 wherein at least one of the detector or sensor elements or means is an electro-mechanical device or element.
7. The method of claim 1 wherein the response element includes or is associated with a motor associated with the liner supply which, directly or indirectly, affects a change in the rate at which the liner material is fed or drawn from the liner supply.
8. The method of claim 7 wherein the detector or sensor element or means is a trigger type means whereby the duration and/or extent of the change or adjustment in the rate at which the liner material is fed or drawn from the liner supply is preset.
9. The method of claim 7 wherein the detector or sensor element or means is an on-off type element or means whereby the change or adjustment in the rate at which the liner material is fed or drawn from the liner supply initiates when turned on and terminates when turned off.
10. The method of claim 7 wherein the on-off element or means comprises two sensors that are activated by the movement of the dancer element or reciprocating means, one that detects when the dancer element or reciprocating means is positioned to correspond to the shortest liner path length thereby prompting an increase the rate at which the line material is fed or drawn from the liner supply and the second that detects when the dancer element or reciprocating means is positioned to correspond to the longest liner path length thereby ceasing the increased rate at which the line material is fed or drawn from the liner supply.
11. The method of claim 1 wherein the biasing means is a helical spring or a coil spring.
12. The method of claim 1 wherein the biasing means is a counter weight or a pneumatic or hydraulic biasing device.
13. The method of claim 1 wherein the biasing means acts directly upon the dancer element or reciprocating armature device.
14. The method of claim 1 wherein the tensioning device comprises at least two stationary elements and a single non-stationary element wherein the non-stationary element is situated between two stationary elements along the pathway of the liner material through the tensioning device or means.
15. The method of claim 1 wherein at least one stationary element is situated before the non-stationary element along the path of the liner through the tensioning device or means.
16. The method of claim 1 wherein at least one stationary element is situated between the non-stationary element and the mating point along the path of the liner through the tensioning device or means.
17. The method of claim 1 wherein the non-stationary and stationary elements are rollers.
18. The method of claim 1 wherein the fixed end of the dancer element or reciprocating armature is attached to an axel or a rotating or pivoting hub.
19. The method of claim 18 further comprising a biasing arm which is also attached to the axel or hub and the biasing means acts upon or is associated with the biasing arm.
20. The method of claim 1 further comprising a roller element which serves as the mating point.
21. The method of claim 20 wherein the mating point roller element is a double grooved roller.
22. An improved method of slitting a continuous prepreg sheet stock material and winding a resulting plurality of slit tape tows with a liner material in an interleaf winding process wherein the improvement comprises mating each continuous slit tape tow with a continuous tow of the liner material which is maintained at a constant tension at the point at which the two are mated; wherein the tension in the liner material is maintained constant at the point at which the slit tape tow and liner material are mated, the mating point, by use of a tensioning and control apparatus located intermediate a supply of the liner material and the mating point comprising a) a tensioning device or means comprising (i) at least one stationary element, (ii) at least one non-stationary element, said at least one stationary element and said at least one non-stationary element defining a path for the liner material through the tensioning device or means and to the mating point, (iii) a dancer element or reciprocating armature device having a fixed end relative to the stationary element and a reciprocating end which comprises or upon which is seated the non-stationary element such that the non-stationary element is capable of moving in a reciprocating fashion along a path that, at one extreme, corresponds to the longest path for the liner through the tensioning device or means to the mating point and, at a second extreme, corresponds to the shortest path for the liner through the tensioning device or means to the mating point, and (iv) a biasing means acting, directly or indirectly, upon the dancer element or reciprocating armature which biasing means biases the non-stationary element towards the first extreme position corresponding to the longest liner supply path, b) a detector or sensor element or means for detecting at least one of 1) movement of the dancer element or reciprocating armature and, hence, movement of the non-stationary element along the aforementioned path, 2) changes in the tension of the liner material and/or 3) differences in the rate at which the liner material is being fed or drawn from a the liner supply and the rate at which it is being taken up in the winding process, and c) a response element or means for, directly or indirectly, effecting a change or adjustment, at least on a temporary basis, in the rate at which the liner material is fed or drawn from the liner supply to the tensioning device or means.
23. The improved method of claim 22 wherein the tensioning device comprises at least two stationary elements and a single non-stationary element wherein the non-stationary element is between two stationary elements along the pathway of the liner material.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings which form a part of the specification are to be read in conjunction herewith. Like reference numerals are employed to indicate like parts in the various views.
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DETAILED DESCRIPTION
(23) As used herein and in the appended claims, the following terms shall have the meanings as set forth below: A flowable material refers to a solid, semi-solid, gel-like or putty-like material which is subject to creep, flow or movement at temperatures likely to be experience by the material during application/use, handling, storage and/or transport (excluding temperatures intentionally inflicted to induce cure or flow) and/or under conditions of pressure encountered during application, handling, winding, storage and/or transport (again excluding pressure intentionally applied to induce cure or flow). Typically, a flowable material is one that will creep, flow or move, most often without a visually apparent physical change, at temperatures below about 120 F., more typically below 100 F. and/or will show creep, flow or movement under its own weight in commercial stock windings thereof. The term interleaf winding refers to that process by which a tow of a continuous length of a stock material, especially a thermoset or prepreg stock material, is mated with a continuous length of a liner or interliner material and wound about a spool, hub, spindle or the like whereby the stock material is isolated or separated from the previously wound stock material in the winding by the liner material. A cut through the winding perpendicular to the rotational axis of the winding will reveal two spirals, one of the stock material and one of the liner material, each layer of one sandwiched between successive layers of the other. Also, as used herein the terms liner and interliner are used synonymously. The phrases substantially constant, if not constant, tension and constant tension refers to the existence of a sufficient tautness or positive tension in the liner material at the mating point so as to prevent a side-to-side or transaxial sway and/or a twisting in the liner material. Though preferred, it does not mean that the level of tension itself is maintained constant. While it may be desirable to maintain a constant or substantially constant level of tension in the liner tow at or immediately preceding the mating point, such is not critical so long as the necessary tautness or positive tension is maintained at that point. In this regard, it will be appreciated that the level of tension in the liner tow is, in part, a function of the liner tensioning apparatus according to the present teaching, as discussed below. Maintaining tautness in the liner material minimizes, if not prevents, the creation of any unevenness, slack, or irregularities in the winding and/or any misalignment of the liner with the stock material. Generally speaking, the tension in the liner should not exceed a predetermined level, which may be established by and/or is largely a function of a biasing means associated with the liner tensioning apparatus, as discussed below, as well as the physical properties of the liner material.
(24) The present teachings are directed to an improved method and apparatus for the interleaf winding of materials wherein the improvement comprises integrating a liner tensioning apparatus into the pathway of the liner material prior to the point at which the liner and material being wound are mated (the mating point) which liner tensioning apparatus is adapted to maintain a tautness or positive tension in the liner material at and/or immediately preceding the mating point. Specifically, the tensioning apparatus is adapted to detect a) changes in the tension of the liner material as it is being mated with the material being wound and/or b) differences in the rate at which the interleaf material is being fed or drawn from the liner supply and the rate at which it is being taken up in the winding process and when the detected change or difference exceeds certain predetermined or preset limits, the tensioning apparatus, directly or indirectly, causes or initiates a process by which an adjustment, preferably a temporary acceleration, in the rate at which the liner material is drawn from the liner material supply and/or fed to the mating point is effected.
(25) While the apparatus and methods of the present teachings are applicable to any winding process in which a liner is necessary or desirable, it is especially applicable to those winding processes where the material to be wound is a flowable material and/or manifests adhesive, sticky or tacky properties and is in the form of sheets, strips, ropes, and the like. In particular, the present apparatus and processes are especially suited for the winding of prepreg materials, i.e., thermoset resin or thermoplastic impregnated fiber materials, including woven and non-woven fibrous materials. Most especially the present teachings are applicable to the process of slitting and winding of prepreg materials comprising a continuous master sheet, including master rolls (also known as parent rolls), of unidirectional fibers, typically carbon fibers, impregnated with curable resins, including, but not limited to epoxies, cyanate esters, bismaleimides, phenolics, polyimides, and the like: the slit product conventionally known as slit tape.
(26) In order to provide a better understanding and perspective of the present teachings, attention is drawn to
(27) As shown in
(28) The converting center generally comprises two operations, a splicing operation and a slitting operation, preferably in this order. While, as noted below, the splicing operation is optional, it is especially important for the production of slit tape. In the process as shown, as the prepreg material 21 is unwound from the master roll 5 it first encounters a splicer 6. The splicer is employed to allow one to splice the terminal end of one master roll to the beginning end of another as the first is expired: thereby enabling continuous operation as well as the production of spools of slit tape of predetermined length, regardless of the length of the master rolls. The splicer typically comprises heating and compression elements (not shown) to facilitate the splicing. The splicing station may, and preferably does, also incorporate cutting means, e.g., a knife, cool laser, micro-knife, etc., in order to provide a clean cut to the tail end and/or leading end of each master roll, to excise a master roll for replacement with a new master roll of the same or a different material to be slit, or to insert a roll of a filler material, e.g., liner material, a polymer film or a non-woven polymer fiber sheet, to complete the slitting and winding operation on the material being slit and wound while concurrently priming the apparatus for subsequent use. In the latter instance, this is typically done when one is preparing the apparatus for shut down. By priming the apparatus, one does not need to manually feed the new material through the whole of the apparatus when the system is to be restarted with a new material since the pathways are already primed with the filler material. Rather, all that is necessary is to splice the new roll of material to be slit to the filler material and allow the system to run: the primer material will lead and pull the new material through the system and to the winders.
(29) When not conducting a splicing operation, the splicing station is merely a pass-through station with the structure of the splicing station doing nothing more than, perhaps, helping with the proper alignment of the sheet material as it enters the slitting station 7. Specifically, those elements of the splicing station associated with the splicing operation or process itself are typically withdrawn or pulled back from the pathway of the prepreg sheet material and are only advanced to be in contact with the prepreg sheet material when a splice is to be made. Splicing techniques and their associated elements and apparatus are well known and commercially available from multiple sources and, therefore, further details and explanation thereof is not necessary.
(30) The second operation encountered by the prepreg material in the converting center is the slitting operation. This is accomplished by a slitter 7 which slits the prepreg material into a predetermined number of tows of slit tape 22. Slitting may be accomplished by any of the known methods appropriate for the material being slit, e.g., precision, high strength blades, cool lasers, micro-knives, diamond knives, and the like. In the case of prepreg materials, it is preferred that the cutting be accomplished through a knife or blade system. Such systems are well known and commercially available and, therefore, further details and explanation thereof is not necessary.
(31) Intermediate the converting center 2 and the winding center 3 are a plurality of alignment elements including rollers, guide posts, guide elements, positioning elements, tension controllers, aligners and the like, all of which are in the public domain and employed in conventional winding systems. These alignment elements are responsible for directing each tow of slit tape from the slitting station to its proper winding station and, ultimately, its intended spool or spindle element and, preferably, while maintaining a constant tension on the slit tape throughout this pathway. Not all systems will employ all of these elements. For example, systems configured to wind wide slit tape, i.e., those wound in a pancake coil, generally 3 or more in width, will require fewer of these elements than a system, as depicted in
(32) Conversely, in the case of narrow slit tape, as shown in
(33) The key center of the slitting and winding system 1 as relates to the present improvement is the winding center 3. The winding center has two key functions, winding the slit tape 22 on the spool 26 and interleafing a liner material 24 between each winding of the slit tape 22. This process is accomplished at a plurality of spooling stations 10 each of which is typically mounted on or supported by a vertical wall or support structure (not shown). Each spooling station generally comprises an axel on which is mounted a spool, spindle, or bobbin and about which the slit tape is wound, which axel is directly or indirectly attached to or engaged with a drive motor for rotating the axel about its axis.
(34) At each spooling station the slit tape is brought or guided to the spool by a plurality of rollers wherein positioning rollers 16 introduce and feed the slit tape to the mating point, alignment rollers 18 mate and align the slit tape with the liner, and placement roller 20 positions and places the mated slit tape and liner on the spool. Concurrently, a liner apparatus 13 feeds a liner material 24 from a liner material supply 12 to and aligns the liner material with the slit tape 22 for mating. In accordance with the present teachings, the liner apparatus further comprises a liner tensioning apparatus 14. The specific liner tensioning apparatus shown in
(35) As noted above, the key and central element of the improved process and apparatus of the present teachings is the liner tensioning system. In essence, any number of well-known and commercially available devices may be combined and adapted and the combination integrated into an existing interleaf winding system to perform the function of detecting changes in the tension of the liner material and/or detecting differences in the feed and take-up rate of the liner material and, in response to the detection of certain predetermined parameters, directly or indirectly, altering the rate at which the liner is fed or drawn from the source thereof, at least on a temporary basis, to maintain a tautness or constant tension in the liner material at or immediately prior to the point at which it is mated with the material being wound, generally the slit tape. In its simplest of iterations, the liner tensioning system comprises a detector means, a response means, and a tensioning means.
(36) The detector means is adapted to detect changes in the tension of the liner material at or before the mating point and/or to detect differences in the rate of uptake of the liner by the winding spool as compared to the rate at which the same is fed from or drawn from the liner supply. Preferably, the detector means will comprise or have associated therewith preset parameters, limits, or triggers which, upon being met, causes, directly or indirectly, the activation, initiation, signaling, or instructing of the response means, as described below, to accelerate, at least on a temporary basis, the rate at which the liner material is fed or drawn from the liner supply. Most preferably the detector means and the response means are interconnected so that the acceleration in the feed or draw rate of the liner material is stopped once a second preset parameter or trigger is detected by the detector means or the parameter or trigger which initiates the response means to begin with no longer exists, i.e. is rectified by the accelerated feed of the liner material. The detector means generally comprises one or more switches, sensors and the like depending upon the specific interleaf winding system into which it is integrated and the specific design and elements of the tensioning apparatus as a whole.
(37) Suitable sensors include transducers and loaded cell tension detectors, single and triple roller tension transducers, strain gauge sensors, etc. which detect tension in the tow of liner material. Alternatively, the sensor may be integrated into the unwinding unit, e.g., the axel on which a spool of the liner material is loaded, which sensor is configured to detect higher draw rate or pull of the liner material. Such a sensor could also be integrated into the spool winding motor or axel to detect an increase in resistance to the winding process; however, this configuration is less desirable as the cause for the increased resistance could also be an issue with the supply of material being wound.
(38) Electronic and mechanical switches, especially electronic eyes, electrodes or electrical contacts, are also suitable for the present application. In these embodiments the tensioning apparatus has one or more stationary and one or more, preferably only one, non-stationary elements. These elements may be in the form of rollers, guides, pins, etc. (anything that will allow the liner to pass over or through it without snagging and, preferably, while maintaining its alignment). The stationary elements comprise or contain at least one element of the switch and define the limit, or, if there are two, the limits of movement of the non-stationary element. Specifically, one stationary element, the primary stationary element, is positioned to correspond to the maximum liner tension/shortest length of liner between the liner supply and the mating point allowed, the advanced position. A second stationary element, the secondary stationary element, if present, is positioned to correspond to the minimum liner tension/maximum length of liner between the liner supply and the mating point allowed, the retracted position. The retracted position is generally that position which coincides with the system at rest, i.e., in a non-operating mode. Alternatively, the retracted position may, and most typically will, coincide with the system in that operational mode when the length of liner material between the liner supply and mating point is at its maximum in-operation length, which may also be the rest mode. The non-stationary element is associated with the tension in and/or length of the liner material and is biased towards the retracted position and may or may not comprise a part of the switch or sensor. When the tension is low or the length of liner material between the liner supply and the mating point is at or near the maximum length, the non-stationary element is positioned at or near the secondary stationary element or the retracted position if no secondary stationary element is present. Conversely, when the liner tension is high or the length of liner material short, the non-stationary element is positioned at or near the advanced position. Generally speaking, however, the tendency and trend is for the non-stationary element to gradually move towards the advanced position owing to the difficulty in matching the rate of liner feed to the take-up rate from the winding process.
(39) During processing, when the non-stationary element moves past or contacts the primary stationary element, it triggers the response means to induce or effect an acceleration in the rate at which the liner is fed from or drawn from the liner supply. This acceleration may be for or of a predetermined duration or its duration may be determined by the first or, if present, the second stationary element. In the former, the response means may be pre-programmed to accelerate the release of liner material for a set period of time or until a set length of material has been released. In the latter, if the trigger is an electric eye or an electrode or electric contact, the acceleration in the rate of feed or draw of the liner material may only proceed as long as the interference with the electric eye or the electric contact exists. Owing to the biasing of the non-stationary element to the retracted position, as additional liner material is released or fed, the non-stationary element will move back towards the retracted position, breaking contact with the electrode or electric contact or removing itself from the vision of the electric eye, thereby terminating the acceleration in the liner release rate. Alternatively, if a secondary stationary element is present, the acceleration of the release of liner material may continue until the non-stationary element passes or contacts the secondary stationary element. This latter configuration effectively provides separate on and off switches whereas in each of the previous embodiments the primary stationary element comprises a single on/off switch.
(40) In yet another embodiment, the stationary elements may contain elements of an electro-mechanical switch, e.g., a toggle or sliding switch, which are moved from one position to another when the non-stationary element passes or contacts that switch. In this regard, when only a primary stationary element is present, the switch is physically moved or manipulated from an off position to an on position, but is biased towards the off position. In this configuration, when contact is made and the switch moved to the on position and liner released, the bias of the non-stationary element moves the non-stationary element back away from the switch and the bias of the switch element of the stationary element returns the same to the off position. Alternatively, the mechanical switch may comprise a slide switch one portion of which is positioned as the primary stationary element and another positioned as the secondary stationary element. When the non-stationary element moves past the primary stationary element, it slides the switch to an on position, concurrently moving the switch element of the secondary stationary element. When liner is released, the non-stationary element moves back to the retracted position, contacting and moving the switch element of the secondary stationary element back to the off position.
(41) Finally, it is also contemplated that the switch may be a fully mechanical switch whereby the movement of the non-stationary element moves a lever or like device which in turn causes the acceleration in the liner release. This lever would be biased towards the non-active position so as to stop the acceleration in the liner release once the non-stationary element moves back, away from the lever.
(42) The second critical element of the interliner tensioning apparatus is the response means. The response means is a device capable of and/or adapted to bring about an acceleration in the release (i.e., feed or draw) of the liner material from the liner supply. The specific device depends, in part, upon the nature of the liner material supply. For example, when the liner supply is a loose bale of the liner material, most typically a loose pack of the liner material in a bag, box or barrel, the liner is typically drawn from the supply by a plurality of pinch rollers, one of which is motorized or connected to a motor to cause its rotation. The pinch between the motorized roller and the second roller pulls the liner from the liner supply. To ensure proper alignment and avoid snags, the pinch roller apparatus typically has a loop element or eye bolt like element or other similar device having a small pass-through, e.g., a slit, through which the liner passes as it is drawn into the pinch roller. When the trigger or detector elements described above are activated, the pinch rollers will accelerate the rate of rotation to spew out additional length of liner material.
(43) Preferably, the liner material is wound about a spool or spindle, either as a pancake coil or a transverse winding, which spool or spindle is mounted on an axel which is connected, directly or indirectly, to a motor. The motor may be active or passive. In the former, the motor assists in the unwinding of the liner material and is accelerated, increasing the rate of rotation of the axel, when activated or initiated by the detector means. In the latter, the axel is generally in a freely rotating state whereby the liner material is drawn from the liner supply by the pull of the liner material as it is being wound on the winding element. To avoid the unintended expulsion of excess liner material should the winding process suddenly stop, the axel may and preferably does have or is adapted to have a minor drag or resistance to its free rotation. The amount of drag or resistance is minimal so as to be readily overcome by the pull associated with the normal uptake of the liner material as the liner and slit tape is wound. In the passive system, when activated or initiated by the detector means, the motor, preferably a servo motor, engages the axel and accelerates its rotation. The duration of the acceleration may be predetermined or preset to run for a specified period of time or until a specified amount of liner material has been expelled. Alternatively, the duration may be responsive to the stimulus or instructions of the detector means, all as discussed in greater detail above.
(44) In yet another embodiment, the spool or spindle of the liner material may be mounted on an axel whose rotation is restricted, requiring a certain pull tension in the liner to unwind the liner material. This is a passive liner dispenser in that the draw of the liner from the supply is purely line tension in the liner material arising from the winding process. The restriction in the axel rotation is most typically imposed by the presence of a braking element or like element which acts directly or indirectly upon the rotation of the axel. Specifically, the drag or resistance is either imposed directly on the liner axel or directly upon spool or spindle of liner material, which indirectly limits the rotation of the axel upon which it is mounted. In this instance, when the detector means is activated or initiated, the restriction on the axel rotation is removed or lessened, i.e., the extent of braking is lessened or removed altogether, whereby the tension in the tensioning means, as noted below, adds pull to the already tensioned liner material, accelerating its draw from the spool. The brake is reapplied once the stimulus for the removal or lessening thereof is removed.
(45) The last and equally critical element of the liner tensioning apparatus is the tensioning means. The tensioning means is any device that is adapted to or capable of taking up the additional liner material expelled in response to the acceleration in the feed rate or draw rate of the liner material while concurrently maintaining a tautness or positive tension in the liner material at or immediately before the mating point in the winding process. The tensioning means is positioned in the liner pathway intermediate the liner supply and the mating point, most preferably in close proximity to the winding means, and is biased, typically by way of a helical spring, coil spring, counter-weight, or a pneumatic or hydraulic device, to increase the tension in the liner material. Though many devices may be employed, as those skilled in the art will readily appreciate, typically the tensioning means employs a dancer element or armature which reciprocates from a position corresponding to a long length of liner material between the liner supply and the mating point to a position corresponding to a short or shorter length of liner material between the liner supply and the mating point. It is to be appreciated that the tensioning means, or a portion thereof, is associated with or comprises or forms a part of the detector means: particularly the non-stationary element of the detector means.
(46) Preferably the tensioning means comprises two stationary guide elements and one non-stationary guide element intermediate the other two with the non-stationary element most preferably mounted on a dancer arm or reciprocating armature. As noted above, the non-stationary guide element is preferably associated with the non-stationary element of the detector means. On the other hand, the stationary guide elements are most typically distinct from the stationary elements of the detector means. Furthermore, it is to be appreciated that the second of the stationary guide elements may serve as the mating point of the liner material and slit tape.
(47) In operation, the non-stationary guide element reciprocates from a position in close proximity to one or both stationary guide elements (corresponding to the shortest liner path from the first to the second stationary elementthe advanced position as noted above) to a position removed from the stationary guide elements (corresponding to a lengthy or longer liner path from the first to the second stationary elementthe retracted position). The non-stationary guide element or the armature on which it is mounted is biased to the latter position, ensuring a tautness or positive tension in the liner material between the non-stationary element of the tensioning means and the mating point. The movement of the non-stationary guide element and/or the arm or armature on which it is mounted effects of forms a part of the detector, directly or indirectly triggering or leading to the activation of the response means. Suitable guide elements are any device that is capable of positioning and aligning the liner material along a set path. Typically the guide elements are rollers over which the liner passes or an eye bolt like element or other shaped element, such as those having a J, U, or O shaped portion through which the liner passes, or any combination of the foregoing; most preferably rollers.
(48) The liner tensioning system may be incorporated into any apparatus or system used to wind tapes or strips of materials wherein the successive windings are or must be isolated from the prior winding. This is especially applicable to the winding of such tapes and strips made of or comprising a flowable material or an adhesive, tacky or sticky material, most especially prepreg materials. They may be integrated into the manufacturing process thereof or they may be integrated into converting systems and apparatus which convert master rolls of the sheet material into tapes or strips of the material, most especially slit tape. The incorporation and employment of the liner tensioning system and apparatus improves yields in terms of both quality and quantity, allowing for faster winding processes with less or minimal defects or out-of-specification product.
(49) Having described the new liner tensioning system and its operation in general terms above, attention is now directed to the figures which depict various specific embodiments and iterations of the liner tensioning system and its integration into an interleaf winding system, particularly a prepreg slitting and winding system. Though not shown in all the figures, it is to be appreciated that the winding or spooling stations as well as the liner tensioning system and assemblies described and presented in the figures are mounted on a support structure or wall.
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(51) The spooling station also comprises a plurality of roller and alignment elements including positioning rollers 16, alignment rollers 18 and placement roller 20 for introducing and feeding the slit tape 22 to the mating point at the first of the two alignment rollers 18, passing the mated slit tape and liner through the second alignment roller and to the placement roller and, finally, onto the spool 26. The spool in this particular figure is a pancake spool having side walls 34 for help in maintaining the pancake form and alignment of the subsequent windings, one directly overlaying the other. The spool 26 is mounted on a spool axel 32 which is driven or rotated by a motor, not shown. In this embodiment, the rotation of the axel, and hence the spool, during the winding process is counter-clockwise thereby enabling an inversion of the mated slit tape and liner as it is placed on the spool, i.e., the liner overlays the slit tape as the two approach the spool yet the liner lies under the slit tape as the two are wound on the spool.
(52) Typically the positioning and alignment rollers are standard rollers 50 having a single groove 51 about the roller core 52, all as shown in
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(55) The
(56) The liner supply assembly 92 comprises a spool 96 of liner material 97 mounted on an axel 94 whose rotation is enabled or supplemented by a motor 98 on the opposite side of the superstructure 61.
(57) The winding spool assembly 74 comprises a spindle type spool element 76 on which the slit tape/liner material is wound. The spool is mounted on a spool axel 75 whose rotation is controlled by motor 78.
(58) Transverse winding of the slit tape/liner combination is accomplished by means of a carriage assembly 67 and a motorized worm shaft/axel assembly 100 on which the carriage rides. Operation of the worm is controlled by motor 102 which is connected, directly or indirectly, e.g., by one or more gear elements, to the worm element (not shown) of the motorized worm shaft/axel assembly. The worm element has a continuous crisscrossing helical groove in its circumferential surface which engages a non-rotating slide element associated with the carriage assembly whereby as the worm is rotated in response to the action of motor 102, the slide element moves along the groove, carrying with it the carriage assembly.
(59) The carriage assembly itself is comprised of structural elements and non-structural elements, the latter comprising the liner tensioning assembly 84 and the slit tape alignment, positioning and placement guides, rollers, and the like, all of which are mounted on the structural elements. The specific embodiment shown in
(60) The liner tensioning support 82 and the positioning arm 63 are each adjoined to a carriage body 62 which is associated with, most preferably directly connected to, the aforementioned slide element which rides on the worm of the motorized worm shaft/axel assembly 100 and is responsible for the reciprocating movement of the carriage assembly as a whole. Although each of these structural elements are shown as individual elements in the figures, it is to be appreciated that any two or all three of these support or structural elements could just as easily be formed as a single structural piece.
(61) As noted, the carriage assembly as a whole is moveably mounted on the worm shaft/axel assembly 100. While the critical connection between the two is the slide element, it is to be appreciated that there is preferably a secondary connection which prevents the one from disengaging the other, especially during operation, and so that the full force or weight of the carriage assembly is not borne by the slider and worm element. Though not shown, those skilled in the art will appreciate that there are preferably one or more bores through the carriage body 62, the axis of which is parallel to the longitudinal axis of the worm element, and through which extend a similar number of rail elements associated with the worm shaft/axel assembly. These rails bear all or at least the brunt of the weight of the carriage assembly yet allow the carriage assembly to smoothly travel and reciprocate along the length of the rails.
(62) A second support, guide bar 104, is also employed to maintain the proper orientation of the positioning arm 63. This support may be stationary or non-stationary and is positioned near the fore end of the positioning arm, in close proximity to the spool so as to counteract the pulling force of the spool assembly as the slit tape is being wound. If the guide bar is stationary, it is positioned so that the positioning arm, most notably the placement roller 72 on the positioning arm, is removed from the spool even when the fully wound. Alternatively, the guide bar may be adapted to move as the winding on the spool grows so as to maintain a constant distance between the placement roller and the spool. This latter configuration minimizes any opportunity for the slit tape 99 and liner 97 to disengage from each other, to shift relative to one another, or to twist. Here, the guide bar is associated with a motorized conveyor means or lift which raises the guide bar, and hence the fore end of the positioning arm, as more and more slit tape is wound and then returns to its starting position when exchanging out the full spool with a new or empty spool. With this configuration, the positioning arm 63 is a separate element and is adapted to pivot, preferably about axel 64.
(63) As noted, the positioning arm has mounted thereon a plurality of roller elements including slit tape positioning rollers 64 and 68, liner positioning roller 69, slit tape/liner alignment rollers 70, and placement roller 72. Slit tape positioning rollers 64 and 68 and liner positioning roller 69 align and position the slit tape and liner, respectively, for proper mating at the mating point, i.e., at the first of the two alignment rollers 70. Alignment rollers 70 align, i.e., center, the slit tape on the liner material (though it is to be appreciated that the two are inverted with the liner on top of the slit tape in the roller). Most preferably, and as depicted in these figures, the alignment rollers are double grooved rollers as discussed above. The combined tow of slit tape and liner is then passed to placement roller 72 which positions the winding on the spool 76.
(64) New to this configuration of a winding system and the critical feature of the present teachings is the liner tensioning apparatus 84. The liner tensioning apparatus shown in
(65) Operation of a liner tensioning apparatus similar to that shown in
(66)
(67)
(68)
(69) Finally,
(70) As noted above, the tensioning armature is biased away from the stationary rollers in an effort to maximize or increase the liner pathway through the liner tensioning apparatus. Many different means and configuration of components can be used to create this bias as well as detect changes in the position of the tensioning armature, vis--vis the stationary rollers. Several devices and iterations are shown in
(71)
(72)
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(74)
(75) As noted previously, during the winding process the rate at which the liner is released from the liner supply is typically slower than the rate of its consumption. This, in turn, results in a shortening of the liner path through the liner tensioning assembly and movement of the tensioning armature close to the secondary rollers (
(76) Up to this point, it is to be noted that the discussion has focused on the sensor or detector being associated with or integrated into the biasing means or positioned to be effected by the movement of the tensioning armature. In those embodiments, activation or acceleration of the liner supply motor is responsive to the sensor whereby the duration of the acceleration of the liner supply motor is predetermined, i.e., once triggered it expels liner material for a given time or length of material or is a function of the duration of the stimulus triggering or setting off the sensor, i.e., acceleration stops once the tensioning armature loses contact with or moves out of sight of the sensor, the tension in the spring or the pressure in the cylinder is lessened, etc. Alternatively, it is to be appreciated that the liner tensioning system may employ a plurality of sensors or detectors, one of which triggers or initiates the rate acceleration of the liner supply motor and the other of which terminates the rate acceleration.
(77)
(78)
(79) As noted above, the slitting and winding system as shown in
(80) While the method and apparatus of the present specification have been described with respect to specific embodiments and figures, it should be appreciated that the present teachings are not limited thereto and other embodiments utilizing the concepts expressed herein are intended and contemplated without departing from the scope of the present teaching. Thus true scope of the present teachings is defined by the claimed elements and any and all modifications, variations, or equivalents that fall within the spirit and scope of the underlying principles set forth herein.