Patent Publication Number: US-6658825-B1

Title: Apparatus for packaging fibers, and article produced by same

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to fiber packaging, and more particularly, to compacting and packaging fibers into a bag for mixing into concrete. 
     BRIEF DESCRIPTION OF THE PRIOR ART 
     Synthetic fibers of all types are commonly cut into short and/or random lengths for use as secondary reinforcement in concrete or cement based structures. The fibers are typically packaged in paper bags that can be placed directly into a concrete ready mix truck, a central batch plant, or another mixer for distribution throughout concrete or the like. The combined mixing action of the mixer blades and concrete materials such as cement, sand, water, and/or aggregate contributes to a physical deterioration of the bag. As the bag breaks down the fibers are then distributed by the mixing action into the concrete. 
     Fiber-reinforced concrete made with these bagged fibers sometimes has problems attributable to inadequate or non-uniform mixing and dispersion of the fibers in the concrete. The bags are typically made of a heavyweight paper such as 30 lb. paper to produce a strong and thick package to hold the fibers contained therein. 
     Such bulky bags are slow to break down in the mixer because they merely flop around in the mixer until they get wet enough to break down. This prolonged mixing operation wastes time and energy. When the bags have become sufficiently saturated to break down, most of the mixing cycle is completed, thus leaving the fibers undistributed and clumpy. The end result can be a concrete structure with fibers that are not uniformly distributed in all directions, thereby producing a secondary reinforcement system that is ineffective for shrinkage crack control in the concrete. 
     Several techniques have been and/or are currently being employed for packaging fibers into bags, none of which adequately solves the above-described problems. The simplest technique is a manual bagging operation where individuals place the fibers in plastic bags, weigh the contents, make adjustments to the fiber content until a desired weight is achieved, and heat seal the bag. The plastic bags have to be torn open manually before the contents are placed into the truck or central mixer for dispersion. 
     An improvement to this manual operation has been developed that utilizes form, fill and seal equipment. This equipment allows for a paper bag to be formed, pre-weighed fibers placed inside the bag, and the bag sealed, all in one continuous operation. This is an automatic system and improves accuracy and productivity. However, even with this improved system, relatively large, thick, and heavy bags are required to hold the volume of fibers typically desired. 
     Additionally, several techniques are known to have been attempted for packaging fibers into lighter weight bags, none of which has been successful or practical in addressing the above-described problems. Difficulties arise in attempting to package the fibers in a lightweight paper bag that breaks down more quickly in the mixer, while also providing a compact package as is desired for efficient storage and transport, easy handling, automatic batching, and easy distribution into the concrete. 
     Attempted solutions are known to have included modified bulk handling equipment with blowers, bag dispensers, and other bagging concepts such as multiple bags that are linked together like sausages. These attempts have been unsuccessful or the final product too expensive to be practical in the industry. The major problem with such bulk dispensing equipment is that the synthetic fibers are very difficult to handle. The fibers have a natural tendency to bridge, thus blocking the feed mechanism, clogging up the system, and shutting down the equipment. Furthermore, attempting to compact fibers into lighter weight bags has proved difficult because the lightweight bags tend to burst during the packaging process. 
     An example of known bulk handling equipment is provided by U.S. Pat. No. 5,074,101 to Rewitzer, which discloses a process and apparatus for packaging and pressing loose fibers comprising a fill shaft with distributing and clearing means such as a pivotal trunk, flap, or paddle and screw conveyors. The fill shaft is connected to a rectangular press container having box bag lined therewithin for holding the loose fibers which are then compressed by a press ram. Another known bulk handling system is provided by U.S. Pat. No. 5,623,811 to Hirschek et al., which discloses a process and device for packaging and supplying fiber material comprising a container for fiber material, a hopper and fill device connected to the container, and a press ram for compacting the fiber therein. Neither Rewitzer nor Hirschek et al. provide for compacting fibers into a lightweight bag to overcome the aforementioned problems. 
     There is also known the device of U.S. Pat. No. 4,004,398 to Larsson et al., which discloses equipment for packaging pulverized material such a coffee in a flexible film container made of foil or plastic. The equipment comprises a firm container around which the film is formed into the flexible container. A table supports the containers and is raised and lowered. A piston moves up and down in the firm container for compacting the material. Larsson et al. does not provide a device suitable for bulk packaging of fibers in lightweight paper bags. 
     Accordingly, what is needed but not found in the prior art is an apparatus and method for packaging fibers in a bag in which the fibers are handled without clumping and clogging the handling equipment and the fibers are compacted into the bag without bursting the bag, and the bagged fiber article produced thereby in which the bag is capable of breaking down quickly and easily in the mixer to produce a uniform distribution of the fibers in the concrete. 
     SUMMARY OF THE INVENTION 
     Generally described, the present invention provides an apparatus for packaging fibers in a bag, comprising at least one base plate and at least one fill tube having a lower section, a middle section, and an upper section. The lower section of the fill tube has a bottom spaced apart from the base plate so that the bag may be placed between the bottom of the lower section and the base plate. 
     At least one bag liner tube is slidably coupled to the lower section so that the bag liner tube may slide between an up position and a down position. The up position provides the bag liner spaced apart from the base plate so that the bag may be placed between the bag liner and the base plate. The down position provides the bag liner generally adjacent to the base plate. 
     At least one ram slides within the fill tube between an up position within the upper section and a down position within the middle and lower sections. At least one feed tube is attached to the middle section, and at least one distribution bin is attached to the feed tube. At least one rotating pin assembly may be provided in the distribution bin, and an electric control may be provided for the rotating pin assembly wherein loose fibers may be advanced through the distribution bin at a uniform rate. 
     The bag is positioned over the bag liner tube so that the bag liner tube absorbs the sidewall forces and the base plate absorbs the bottom wall forces resulting from compacting the fibers therein. The bag itself is therefore not subjected to these temporary maximum forces so that the fibers can be compacted therein without the bag bursting. 
     The method of the present invention generally comprises the acts of mounting a bag over a bag liner tube that is in an up position relative to a lower section of a fill tube, sliding the bag liner tube to a down position such that the bag liner tube is adjacent a base plate, advancing a predetermined volume of loose fibers into a middle section and a lower section of the fill tube while a ram is in an up position within an upper section of the fill tube, sliding a ram to a down position in the bag liner tube and bag wherein the loose fibers are compacted into the bag liner tube and bag, sliding the bag liner tube to the up position relative to the lower section of the fill tube, sliding the ram to the up position within the upper section of a fill tube removing the bag from the bag inner tube, and sealing the compacted fibers in the bag. 
     The act of advancing the loose fibers may comprise rotating pins in a distribution bin attached to a feed tube attached to the middle section of the fill tube. The acts may be repeated as desired for mass production of bags of compacted fibers. The present invention also provides an article produced by the above-described method, comprising a bag of compacted fibers. 
    
    
     The objects, features, and advantages of the present invention are further discussed and/or apparent in the following detailed description of the invention, in conjunction with the accompanying drawings and the appended claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features and advantages of the invention will be apparent from the attached drawings, in which like reference characters designate the same or similar parts throughout the figures, and in which: 
     FIG. 1 is a perspective view of one embodiment of the apparatus of the present invention; 
     FIG. 2 is an elevation view of one embodiment of the apparatus of the present invention; 
     FIG. 3 is a detail view of a portion of FIG. 2; 
     FIG. 4 is a detail view of a portion of FIG. 2; 
     FIG. 5 is a detail view of a portion of FIG. 2; 
     FIG. 6 is a detail view of a portion of FIG. 2; 
     FIG. 7 is an elevation view of the embodiment of FIG. 1 with the bag mounted onto the bag liner tube; 
     FIG. 8 is an elevation view of the embodiment of FIG. 1 with bag and bag liner tube in the down position; 
     FIG. 9 is an elevation view of the embodiment of FIG. 1 with fibers advanced into the fill tube; 
     FIG. 10 is an elevation view of the embodiment of FIG. 1 with ram compacting the fibers; 
     FIG. 11 is an elevation view of the embodiment of FIG. 1 with the bag liner tube being raised; 
     FIG. 12 is an elevation view of the embodiment of FIG. 1 with the ram being raised after compacting the fibers; and 
     FIG. 13 is a perspective view of one embodiment of the article produced by the method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 and 2, there is illustrated one of many embodiments of the apparatus, referred to generally as  10 , of the present invention for packaging fibers  12  in a bag  14 . The apparatus  10  may be used for packaging fibers  12  such as threads, strands, strips, wires, particle matter, interstitial materials, composites, or other fibrous materials made of polypropylene, nylon, polyethylene, polyester, carbon, composites, or other synthetic or organic materials. The bag  14  used with the apparatus  10  may be made of a thin, lightweight material such as 20 lb. weight paper or the like. The material of the bag  14  is selected to be sufficiently strong to contain therein the fibers  12  in a compacted state during shipping and handling, yet sufficiently thin and lightweight to burst and deteriorate quickly when agitated by a mixer blade. The material of the bag  14  does not, however, need to be sufficiently strong to withstand the maximum forces temporarily exerted on the bag  14  during compacting and packaging of the fibers  12  therein with the typical packaging equipment described hereinabove. It should be noted that the apparatus  10  may be provided with a plurality of the below-described elements, however, the apparatus  10  and elements thereof are generally described herein in the singular for simplicity of explanation. For example, two apparatus  10  may be provided in a station operated by one person, so the operator can remove and seal the bag from one apparatus  10  while another apparatus  10  is in the midst of the weighing, feeding, and filling processes. 
     The apparatus  10  has at least one base plate  16  which may be provided by a floor or by a plate raised off the floor such as mounted on a frame  17 , and made of metal, wood, plastic, a composite, or another material, or by another base plate structure known to those skilled in the art. A frame  18  is provided spaced apart from the base plate  16 , and may be made of metal, wood, plastic, a composite, or another material. The frame  18  and base plate may be provided as separate components attached or unattached to each other, or may be integrally formed as a single structure. 
     At least one fill tube  20  is provided having a lower section  22 , a middle section  24 , and an upper section  26 . The fill tube  20  may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. The fill tube  20  may be generally vertical to allow the fibers  12  to flow downward under the force of gravity or may be generally horizontal where a blower or the like is used. The fill tube  20  may have a cross sectional shape that is generally circular, rectangular, polygonal, or another regular or irregular shape. 
     The lower section  22  of the feed tube  20  has a length such that a bottom  28  thereof is spaced apart from the base plate  18  and spaced apart from the frame  18 . At least one bag liner tube  30  is slidably coupled to the lower section  22 . The bag liner tube  30  is preferably disposed over, but may alternatively be disposed within, the feed tube lower section  22 , and may or may not be in direct contact with the feed tube  20 . The bag liner tube  30  may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. The bag liner tube  30  may have a cross sectional shape that is generally circular, rectangular, polygonal, or other regular or irregular shape. The bag liner tube  30  has a cross sectional area that is substantially the same as or slightly less than a cross sectional area of the bag  14  to allow the bag liner tube  30  to be received by the bag  14 . Where the bag liner tube  30  is disposed over the feed tube  20 , the cross sectional area of the bag liner tube  30  is substantially the same as or slightly larger than the cross sectional area of the lower section  22  of the fill tube  20  to allow the bag liner tube  30  to slide on the lower section  22 . Also, the bag liner tube  30  has a length that is the substantially the same as or greater than the length of the bag  14 . 
     The bag liner tube  30  slides between an up position and a down position relative to the feed tube lower section  22 . The up position provides a bottom  32  of the bag liner tube  30  spaced apart from the base plate  16  and the down position provides the bag liner tube bottom  32  generally adjacent to the base plate  16 . The spacing of the frame  18  from the base plate  16 , and the spacing of the fill tube lower section bottom  28  from the frame  18  and from the base plate  16 , are selected so that when the bag liner tube  30  is in the up position the bag  14  may be disposed generally between the bag liner tube bottom  32  and the base plate  16 , and when the bag liner tube  30  is in the down position the bag liner tube bottom  32  is generally adjacent to the base plate  16 . 
     The bag  14  is positioned over the bag liner tube  30  so that the bag liner tube  30  absorbs the sidewall forces and the base plate  16  absorbs the bottom wall forces resulting from compacting the fibers  12  therein. The bag  14  itself is therefore not subjected to these temporary maximum forces so that the fibers  12  can be compacted therein without the bag  14  bursting. 
     When the bag liner tube  30  is in the down position, a portion  34  of the bag liner tube  30  extends from the fill tube lower section bottom  28  approximately to the base plate  16 . The middle section  24  of the fill tube  20  has a length such that the combined length of the lower section  22 , the middle section  24 , and the extended portion  34  of the bag liner tube  30  when the bag liner tube  30  is in the down position may hold therein a predetermined volume of loose fibers  12 . The length, cross sectional area, and volume capacity of the bag  14  are selected to hold a predetermined volume of compacted fibers  12 . For a given length of the bag  14  (based on the desired volume of compacted fibers  12 ), a desired density/compactness of the packaged fibers  12  (based on the strength properties of the material of the bag  14 ), and a the readily measurable density/compactness of the loose fibers  12 , a compaction ratio may be determined. The compaction ratio of the loose to compacted fibers  12  is a factor in determining the volume of loose fibers  12  to be compacted per bag  14  and the length of the middle section  24 , the lower section  22 , and the bag liner tube extended-portion  34 . For example, for a compaction ratio of 10:1, the combined length of the middle section  24 , the lower section  22 , and the bag liner tube extended portion  34  is ten times the length of the bag  14 . The compacting is thus able to be accomplished in a single compacting step instead of multiple steps of filling and compacting fibers  12  into the bag  14 . It should be noted that the fill tube  20  and/or the bag liner tube  30  may be provided with movable sidewalls whereby the fibers  12  may also be compacted from the sides. 
     Referring to FIG. 3, the sliding of the bag liner tube  30  on the fill tube lower section  22  between the up and down positions may be accomplished by incorporating a control system having at least one and preferably two hydraulic or pneumatic cylinders  31  operatively coupled to the bag liner tube  30 , for example, by at least one and preferably two brackets  33  extending from exterior walls of the bag liner tube  30 , or by another control system known to those skilled in the art. Also, the bag  14  is preferably attached to the bag liner tube  30  by a snug friction fit with the bag  14  circumference or perimeter slightly greater than that of the bag liner tube  30 , or may alternatively be attached by providing tabs or a flange extending from the top of the bag liner tube  30  over which the bag  14  may be folded or otherwise attached. 
     At least one ram  36  is slidably disposed within the fill tube  20  such that the ram  36  may slide between an up position within the upper section  26  and a down position within the middle and lower sections  22  and  24 . The ram  36  may be provided by an elongated member, a flat plate, a platen, or another compacting structure known to those skilled in the art, and may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. 
     Referring to FIG. 4, the sliding of the ram  36  within the fill tube  20  between the up and down positions may be accomplished by incorporating a control system having at least one hydraulic or pneumatic cylinder  37  operatively coupled to the ram  36 , or by another control system known to those skilled in the art. For example, at least one bracket assembly  39  may interconnect the ram  36  and the cylinder  37  and extend through at least one slot  41  defined in the fill tube  20 . Alternatively, the cylinder  37  may be provided within the fill tube upper section  26  above and directly coupled to the ram  36 , although this arrangement provides an increased height of the apparatus  10  and may be less suitable in some applications. The cylinder  37  may be provided by, for example, a rod-less air cylinder such as Part No. 50-2021/25X2085 made by the Origa Corporation of Elmhurst, Ill., or by other cylinders known in the art. 
     At least one feed tube  38  is attached to the middle section  24  of the fill tube  20  for feeding fibers  12  thereto. The feed tube  38  may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. The feed tube  38  may be arranged at an acute angle with respect to the fill tube upper section  26  to allow the fibers  12  to flow therethrough into the fill tube  20  under the force of gravity or the feed tube  38  may be generally horizontal where a blower or the like is used. The feed tube  38  may have a cross sectional shape that is generally circular, rectangular, polygonal, or another regular or irregular shape. 
     Referring to FIGS. 5 and 6, at least one distribution bin  40  may be attached to the feed tube  38  for advancing the loose fibers  12  into the fill tube middle section  24 . The distribution bin  40  may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. The distribution bin  40  may have at least one rotating pin assembly  42  disposed therein and at least one electric control  43  that controls the rotating pin assembly  42  to advance the loose fibers  12  therethrough at a uniform rate without clogging. Preferably, each bin  40  has two pin assemblies  42  each comprising rows of staggered pins  45  extending from a rotatable shaft  47 , the shafts  47  preferably rotating in opposite directions  49  and  50  and operatively coupled to at least one variable speed drive such as the Dayton Right Angle Gearmotor, Model IL4843B made by Dayton Electric Mfg. Co. of Niles, Ill., or another drive known in the art. It should be understood that other means for advancing the fibers  12  through the distribution bin  40  may be suitably employed, for example, oppositely rotating and interposed stars, a vibrating screen, or other mechanisms known to those skilled in the art. 
     At least one hopper  44  is attached to the distribution bin  42 , the hopper  44  having an interior space capable of housing the predetermined volume of loose fibers  12 . 
     The hopper  44  may be made of metal, plastic, wood, ceramic, a composite, or another material known to those skilled in the art. 
     At least one weight hopper  53  may be positioned above the hopper  44  for weighing and holding a predetermined volume of loose fibers  12  selected for corresponding to a predetermined volume of compacted fibers  12  capable of containment in a particular sized bag  14 . The weight hopper has control system for selectively releasing the predetermined volume of fiber  12  into the hopper  44 . The control system may be provided by at least one pivotal door  55  operatively coupled to at least one hydraulic or pneumatic cylinder  51  with the door  55  operable by actuation of a foot pedal, lever, pushbutton, or the like, or by another control system known to those skilled in the art. At least one conveyor belt assembly  46  or the like of a type known in the art may be provided generally adjacent to the weight hopper  53  for delivering the loose fibers thereto. Load cells  57  may be associated with the hopper  53  as is known in the art, and the load cells.  57  and the conveyor assembly  46  may be controlled by controllers such as the Model No. WI-130 Weight Indicator and Control System provided by Weigh-Tronix, Inc. of Fairmont, Minn., or by another controller known in the art. 
     The present invention also comprises a method for packaging the fibers  12  in the bag  14 . It should be noted that the method elements may be undertaken in a sequence that varies from the order described herein. The method elements will now be described in detail, with reference to FIGS. 7-12. 
     Referring to FIG. 7, with the ram  36  in the up position within the fill tube upper section  26 , and with the bag liner tube  30  is in the up position relative to the lower section  22  of the fill tube  20 , the bag  14  is mounted over the bag liner tube  20 . Referring to FIG. 8, the bag liner tube  30  is slid  48  to the down position relative to the fill tube lower section  22  such that the fill tube lower section bottom  32  is generally adjacent the base plate  16 . 
     Referring to FIG. 9, the predetermined volume of loose fibers  12  is advanced from the distribution bin  40  through the feed tube  38  into the middle section  24  of the fill tube  20  by rotation  49 ,  50  of the pins  42  within the distribution bin  40 . The fibers  12  may be conveyed into the distribution bin  40  through the hopper  44  and the weight hopper  53  by the conveyor belt  46 . Referring to FIG. 10, the ram  36  is slid to the down position within the bag liner tube  30  and bag  14 , wherein the loose fibers  12  are compacted into the bag liner tube  30  and bag  14 . 
     Referring to FIG. 11, the bag liner tube  30  is slid  54  to the up position relative to the lower section  22  of the fill tube  20 . Referring to FIG. 12, the ram  36  is slid  56  to the up position of FIG. 1, and the bag  14  of compacted fibers  12  is removed from the bag liner  30  and sealed. These acts may be repeated as desired for mass production of bags of compacted fibers. The sealed bag  14  of compacted fibers  12  is added to a concrete matrix in a mixing chamber and agitated by a mixing blade or the like until the bag  14  bursts and the fibers  12  are forced from the bag  14 , allowed to return to a loose uncompacted state, and distributed into the concrete matrix. 
     Referring now to FIG. 13, the present invention also provides an article  58  produced by the method described hereinabove. The article  58  comprises the bag  14  with fiber  12  filled and compacted therein by the method and apparatus  10  described hereinabove. The article  58  may be mixed into a concrete matrix as described herein for reinforcement thereof, or may be mixed into other materials as is known to those skilled in the art. 
     While the invention has been described in connection with certain preferred embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the true spirit and scope of the invention as defined by the appended claims. All patents, applications and publications referred to herein are hereby incorporated by reference in their entirety.