There are no previously filed copending nonprovisional applications or international applications designating the United States of America from which priority is claimed for this application or other related applications to be cross-referenced in this application.
None of the work leading to the present invention was performed under federally sponsored research and development.
This invention relates to an improved apparatus for the high-speed feeding of fiber materials from balls, doffs, cakes or other windings into one or more machines for further processing, and particularly for the high-speed feeding of continuous fibers of glass or synthetic materials.
A common practice during the production of fiber products is to collect and wind strands of filaments onto a carrier to produce a fiber bundle that may be referred to as a ball, winding, package, cake or doff. These fiber bundles are then used to store, transport and supply fiber linearly into processes such as roving, rewinding, braiding, twisting, weaving, plying, knitting, chopping, pultrusion, filament winding, prepregging, wire coating or cabling for the production of products such as chopped strand mat, yarn wound onto bobbins, multi-end rovings or fabrics or other materials. Typically, a number of these fiber bundles are arranged in a creel or other assembly with individual fibers then being drawn from the separate bundles and passed either singly or in combination into one or more subsequent processes.
In many instances, it is helpful to adjust the tension of the fiber as it exits the feed tube to within a desired range, both to control the tension entering any subsequent processing and to provide a generally uniform tension for a plurality of fibers exiting various feed tubes. Winding operations in particular benefit from the use of a tensioning device between the feed tube and the winder to maintain an even tension in the fiber. Although a variety of tensioner designs are available, a spring tensioner capable of applying a uniform tension as the fiber passes at high speed and does not damage the strand even at high tension levels is preferred. Depending on the application, however, other types of tensioners, including post and disc, breaker bars/alligator clips, electromagnetic breaking/tensioning devices and ball-in-tube tensioners, could also be used in conjunction with the basic feed assembly to perform the desired tensioning.
As will be appreciated, the rate at which the final product may be produced is limited, at least in part, by the rate at which the fiber can be drawn from the creel and supplied to the desired manufacturing operation in a safe and sustainable manner. Prior art techniques that have been employed to control and guide the fiber as it is withdrawn from the creel include ring-shaped guides, eyelets and rollers manufactured from various ceramic and metallic materials. Guides fashioned from metals, such as steel, that are subject to corrosion are frequently coated with a layer of polished nickel or chrome to reduce or prevent corrosion of the guide surface and reduce the damage to the fiber as it is drawn through or across the guide. For instance, U.S. Pat. No. 5,273,614 to Grimshaw et al. discloses a particular construction for redirect rollers for guiding spaced tows. U.S. Pat. No. 4,944,077 to Bollen provides a method of reducing the air friction of yarns drawn from a bobbin at high speed in which a region of accelerated air surrounds the yarn. U.S. Pat. No. 6,182,475 to Lee provides yet another yarn guiding device for feeding yarn from a creel to a knitting needle utilizing a yarn guiding assembly constructed from a combination of zirconium oxide and yttrium oxide. Other work has been directed to modifying the creel itself. For example U.S. Pat. No. 5,639,036 to Flamm provides a textile machine in which the creel is pivotably supported on a pivot shaft with the motion of the shaft and the creel being controlled with an electric motor and a transmission belt unit.
It has been the inventors' experience, however, that those systems that include open frame assemblies remain susceptible to wrapping and binding of the fiber as the fiber feed speed increases. When the terminal operation is capable of accepting and using fiber at higher rates, the reduced fiber feed speed directly limits the productivity of the entire operation. Similarly, downtime resulting from fiber breaks and risk to operators presented by flailing ends of broken fibers further compromise efficiency and safety of the operation. The present invention was developed in order to address these limitations and safety issues and thereby allow improved high-speed operation of fiber feed operations.
The present invention relates to an improved high-speed fiber assembly that includes one or more dampening bars, an intake assembly, and feed tubes for transferring one or more fibers from an intermediate winding into an assembly for additional processing which may include operations such as roving, rewinding, braiding, twisting, weaving, plying, knitting, chopping, pultrusion, filament winding, prepregging, wire coating, cabling, tensioning or beaming. The configuration of the claimed assembly allows the fiber to be consumed at draw speeds in excess of 1500 meters/minute while reducing the tendency of the fiber to wrap around feed assembly components. By maintaining and controlling a generally free flow of the fiber, the present invention allows increased run speed, reduced downtime resulting from fiber breaks and improved operator safety. The present invention is suitable for use with a wide number of fibers including polymer fibers such as aramids, polyesters, nylons, polycarbonates (PC), polyethylenes (PE), polypropylenes (PP), polybutylene terephalate (PBT), polyethylene terephalate (PET) and polyphenylenebenzobisoxazole, carbon and metal fibers including steel and copper, various types of glass fibers such as E, ECR, S, C and D type glass fibers, and natural fibers such as jute, hemp, cotton and flax.
The present invention comprises an improved high-speed fiber assembly that includes a dampening assembly comprising one or more dampening bars, an intake assembly, and feed tubes for transferring one or more fibers from an initial winding into an assembly for conducting additional processing such as roving, rewinding, braiding, twisting, weaving, plying, knitting, chopping, pultrusion, filament winding, prepregging, wire coating, cabling, tensioning or beaming.
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After passing over dampening bar 5, the fiber 2 is drawn into an intake housing 7 which provides a large opening 8 defined by a peripheral edge 9 into a cavity that contains and guides the fiber 2 until it exits the intake housing 7 through a small rear opening 11 and enters the feed tube 12. The fiber continues through the feed tube 12 to the feed tube exit 13 where it is fed into another assembly 14 for additional processing such as a tensioner 15 coupled with winder 16. Although a tensioner and winder are illustrated here for the purposes of discussion, the type of additional processing is not generally limited in scope and may include one or more operations such as roving, rewinding, braiding, twisting, weaving, plying, knitting, chopping, pultrusion, filament winding, prepregging, wire coating or cabling, tensioning or beaming or other processes requiring or benefiting from a linear high-speed fiber feed.
The intake housing 7 preferably provides a solid, smooth and durable surface that does not tend to damage or fuzz the fiber and does not suffer undue damage as the fiber is drawn across it at high speeds. Materials such as polished stainless steel, copper and brass have been found to be acceptable for constructing the dampening bars, intake housing and feed tubes for use with glass fibers. Other materials including metals such as chromed or nickeled steel, alloys, composite materials, ceramics, Teflon® or other high molecular weight polymers could also be used singly or in combination in constructing these elements. The key consideration in the selection of an appropriate material is that they wear smoothly and consistently without producing sharp or rough areas that could tend to damage the fiber as it is drawn across the worn surface. For this reason, black iron, uncoated steel and ceramics having a high iron content are generally not preferred for use in combination with glass fibers.
As will be appreciated, the selection of the materials and the sizing of the elements will be selected with regard to the type and size of the fiber being fed through the assembly and the rate at which the fiber will be fed to provide fiber/surface contact conditions that do not result in damage to the fiber or the surface.
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In addition to the indicated spacings, sizings such as the diameter of the upper dampening bar 26, the diameter of the lower dampening bar 28, the diameter and depth of the intake housing, the dimensions of the fiber, and the diameter of the feed tube also require consideration in the construction of a fiber feed assembly for a particular application. As will be appreciated, other embodiments such as illustrated in
When more than one dampening bar is used, it is preferred that the spacing 27 between at least the first two dampening bars contacted by the fiber be maintained at some low multiple of the maximum fiber dimension, typically less than 5, to assist in knocking down and removing loops that may be drawn from the fiber package before the fiber enters the intake housing. Similarly, it is preferred that that distance 25 between the upper dampening bar 5 and the intake housing 7 also be maintained at some low multiple of the maximum fiber diameter, typically less than 15, to provide good control of the fiber entering the intake housing.
With respect to the spacing 29 between the lower dampening bar 3 and the fiber source 1, however, it is preferred that this distance be considerably larger, typically at least 50 times and preferably at least about 100 times the spacing between the dampening bars so that variations in the point on the fiber source 1 from which the fiber is being drawn have a reduced impact on the angle of the fiber as it contacts the first dampening bar. Similarly with respect to the sizing of the intake housing 7, it is preferred that the wider opening 8 be at least about 50 larger, and preferably at least about 100 times larger, than the largest fiber dimension. With respect to the sizing of the feed tube 12, it is preferred that its diameter be at least about 5 times larger, and preferably at least about 10 times larger, than the largest fiber dimension. As indicated in the Example below, a fiber feed assembly with component spacings and sizings within the more preferred range performed very well at high feed rates.
In general, the use of thicker fibers, fibers with higher levels of twist, stiffer fibers, and/or higher feed rates will require an increase in the minimum fiber source to lower dampening bar separation distance (DSDB) in order for the feed assembly to perform in a satisfactory manner. Conversely, when feeding thinner fibers, fibers with lower levels of twist or no twist, more flexible fibers, softer fibers and/or using slower feed rates the DSDB can be reduced while maintaining satisfactory performance. In evaluating the sufficiency of the DSDB and the effect of the dampening bars, no loops or surges of fiber should make it through the intake housing and into the feed tube. If such conditions are observed, corrective action can encompass additional dampening in the dampening bar assembly, increased DSDB or a combination of the these adjustments. Generally, increased DSDB is preferred in situations where minimizing the potential for damaging the fiber is the goal. If space constraints make increasing the DSDB difficult and/or if some damage to the fiber can be tolerated, increasing the degree of contact between the fiber and the dampening bars can be used to improve the linearity of the fiber feed.
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In addition to the generally hemispherical housings illustrated in
The original fiber feed apparatus was configured to draw a series of 600-1470 tex (grams/kilometer) glass fibers (generally oval with approximate dimensions of 0.26 mm×2.18 mm) from a collection of windings arranged on a pallet and pass the fibers through a series of open ring guides and into a feed tube inlet of a feed tube constructed from ¾ inch (1.9 cm) copper tubing. A spring tensioning device was positioned adjacent the outlet of the feed tube to apply a uniform tension to the fiber exiting the feed tube before passing the fiber to a winding operation. With the prior art open ring design, operation of the fiber feed apparatus at feed rates above 200 meters/min tended to result in the fiber wrapping around a portion of the guide ring or its supporting members and breaking or halting the operation.
The original fiber feed apparatus was modified so that the identical glass fiber was drawn from an identical arrangement of windings again arranged on a pallet. According to the invention, however, the glass fiber first passed along a serpentine path through a two-bar dampening bar assembly of 1½ inch (38.1 mm) diameter copper pipes spaced approximately ¼ inch (6.3 mm) apart. The lower dampening bar was positioned at least about 24 inches (61 cm) above the pallet and the upper dampening bar was generally centered approximately ¼ inch (6.3 mm) below a hemispherical stainless steel funnel with a radius of approximately 7½ inches (19 cm) and a smooth interior surface. The stainless steel funnel included a small rear exit through which the fiber was fed into a feed tube constructed from ¾ inch (1.9 cm) copper tubing. With the fiber feed assembly modified in accord with the present invention, it was possible to feed the identical glass fiber from identical packages into the identical spring tensioning device and winding operation at rates in excess of 1500 meters/min without fiber wrapping or binding. This more than sevenfold increase in the sustainable fiber feed rate produced a dramatic productivity improvement over the prior art fiber feed apparatus while simultaneously increasing operator safety.
The description and illustrations of the present invention provided above are merely exemplary in nature and it is anticipated that those of ordinary skill in the art will appreciate that many variations of the specific apparatus described are possible without departing from the spirit and scope of the invention.
Number | Name | Date | Kind |
---|---|---|---|
1956631 | Snyder | May 1934 | A |
2048511 | Newton | Jul 1936 | A |
2581142 | Rea | Jan 1952 | A |
2686018 | Courntney | Aug 1954 | A |
3282304 | Coleman | Nov 1966 | A |
3568949 | Riha et al. | Mar 1971 | A |
4186896 | Brandenberger et al. | Feb 1980 | A |
4471917 | Whisnant | Sep 1984 | A |
4944077 | Bollen | Jul 1990 | A |
5273614 | Grimshaw et al. | Dec 1993 | A |
5639036 | Flamm | Jun 1997 | A |
6045023 | Michard | Apr 2000 | A |
6182475 | Lee | Feb 2001 | B1 |
6511011 | Zeller et al. | Jan 2003 | B2 |
Number | Date | Country | |
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20040011843 A1 | Jan 2004 | US |